1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
9 * All rights reserved.
10 *
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 /*
36 * Dynamic linker for ELF.
37 *
38 * John Polstra <jdp@polstra.com>.
39 */
40
41 #include <sys/param.h>
42 #include <sys/ktrace.h>
43 #include <sys/mman.h>
44 #include <sys/mount.h>
45 #include <sys/stat.h>
46 #include <sys/sysctl.h>
47 #include <sys/uio.h>
48 #include <sys/utsname.h>
49
50 #include <dlfcn.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "debug.h"
61 #include "libmap.h"
62 #include "notes.h"
63 #include "rtld.h"
64 #include "rtld_libc.h"
65 #include "rtld_malloc.h"
66 #include "rtld_paths.h"
67 #include "rtld_printf.h"
68 #include "rtld_tls.h"
69 #include "rtld_utrace.h"
70
71 /* Types. */
72 typedef void (*func_ptr_type)(void);
73 typedef void *(*path_enum_proc)(const char *path, size_t len, void *arg);
74
75 /* Variables that cannot be static: */
76 extern struct r_debug r_debug; /* For GDB */
77 extern int _thread_autoinit_dummy_decl;
78 extern void (*__cleanup)(void);
79
80 struct dlerror_save {
81 int seen;
82 char *msg;
83 };
84
85 struct tcb_list_entry {
86 TAILQ_ENTRY(tcb_list_entry) next;
87 };
88
89 /*
90 * Function declarations.
91 */
92 static bool allocate_tls_offset_common(size_t *offp, size_t tlssize,
93 size_t tlsalign, size_t tlspoffset);
94 static const char *basename(const char *);
95 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
96 const Elf_Dyn **, const Elf_Dyn **);
97 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
98 const Elf_Dyn *);
99 static bool digest_dynamic(Obj_Entry *, int);
100 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
101 static void distribute_static_tls(Objlist *);
102 static Obj_Entry *dlcheck(void *);
103 static int dlclose_locked(void *, RtldLockState *);
104 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
105 int lo_flags, int mode, RtldLockState *lockstate);
106 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
107 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
108 static bool donelist_check(DoneList *, const Obj_Entry *);
109 static void dump_auxv(Elf_Auxinfo **aux_info);
110 static void errmsg_restore(struct dlerror_save *);
111 static struct dlerror_save *errmsg_save(void);
112 static void *fill_search_info(const char *, size_t, void *);
113 static char *find_library(const char *, const Obj_Entry *, int *);
114 static const char *gethints(bool);
115 static void hold_object(Obj_Entry *);
116 static void unhold_object(Obj_Entry *);
117 static void init_dag(Obj_Entry *);
118 static void init_marker(Obj_Entry *);
119 static void init_pagesizes(Elf_Auxinfo **aux_info);
120 static void init_rtld(caddr_t, Elf_Auxinfo **);
121 static void initlist_add_neededs(Needed_Entry *, Objlist *, Objlist *);
122 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *,
123 Objlist *);
124 static void initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail,
125 Objlist *list);
126 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
127 static void linkmap_add(Obj_Entry *);
128 static void linkmap_delete(Obj_Entry *);
129 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
130 static void unload_filtees(Obj_Entry *, RtldLockState *);
131 static int load_needed_objects(Obj_Entry *, int);
132 static int load_preload_objects(const char *, bool);
133 static int load_kpreload(const void *addr);
134 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
135 static void map_stacks_exec(RtldLockState *);
136 static int obj_disable_relro(Obj_Entry *);
137 static int obj_enforce_relro(Obj_Entry *);
138 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
139 static void objlist_call_init(Objlist *, RtldLockState *);
140 static void objlist_clear(Objlist *);
141 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
142 static void objlist_init(Objlist *);
143 static void objlist_push_head(Objlist *, Obj_Entry *);
144 static void objlist_push_tail(Objlist *, Obj_Entry *);
145 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
146 static void objlist_remove(Objlist *, Obj_Entry *);
147 static int open_binary_fd(const char *argv0, bool search_in_path,
148 const char **binpath_res);
149 static int parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
150 const char **argv0, bool *dir_ignore);
151 static int parse_integer(const char *);
152 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
153 static void print_usage(const char *argv0);
154 static void release_object(Obj_Entry *);
155 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
156 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
157 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
158 int flags, RtldLockState *lockstate);
159 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
160 RtldLockState *);
161 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
162 static int rtld_dirname(const char *, char *);
163 static int rtld_dirname_abs(const char *, char *);
164 static void *rtld_dlopen(const char *name, int fd, int mode);
165 static void rtld_exit(void);
166 static void rtld_nop_exit(void);
167 static char *search_library_path(const char *, const char *, const char *,
168 int *);
169 static char *search_library_pathfds(const char *, const char *, int *);
170 static const void **get_program_var_addr(const char *, RtldLockState *);
171 static void set_program_var(const char *, const void *);
172 static int symlook_default(SymLook *, const Obj_Entry *refobj);
173 static int symlook_global(SymLook *, DoneList *);
174 static void symlook_init_from_req(SymLook *, const SymLook *);
175 static int symlook_list(SymLook *, const Objlist *, DoneList *);
176 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
177 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
178 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
179 static void *tls_get_addr_slow(struct tcb *, int, size_t, bool) __noinline;
180 static void trace_loaded_objects(Obj_Entry *, bool);
181 static int try_fds_open(const char *name, const char *path);
182 static void unlink_object(Obj_Entry *);
183 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
184 static void unref_dag(Obj_Entry *);
185 static void ref_dag(Obj_Entry *);
186 static char *origin_subst_one(Obj_Entry *, char *, const char *, const char *,
187 bool);
188 static char *origin_subst(Obj_Entry *, const char *);
189 static bool obj_resolve_origin(Obj_Entry *obj);
190 static void preinit_main(RtldLockState *lockstate);
191 static void rtld_recalc_bind_not(const char *);
192 static void rtld_recalc_dangerous_ld_env(void);
193 static void rtld_recalc_debug(const char *);
194 static void rtld_recalc_path_rpath(const char *);
195 static int rtld_verify_versions(const Objlist *);
196 static int rtld_verify_object_versions(Obj_Entry *);
197 static void object_add_name(Obj_Entry *, const char *);
198 static int object_match_name(const Obj_Entry *, const char *);
199 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
200 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
201 struct dl_phdr_info *phdr_info);
202 static uint32_t gnu_hash(const char *);
203 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
204 const unsigned long);
205
206 struct ld_env_var_desc;
207 static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd);
208 static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd);
209 static void rtld_set_var_debug(struct ld_env_var_desc *lvd);
210 static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd);
211 static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd);
212 static void rtld_set_var_library_path(struct ld_env_var_desc *lvd);
213 static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd);
214 static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd);
215 static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd);
216
217 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
218 void _r_debug_postinit(struct link_map *) __noinline __exported;
219
220 int __sys_openat(int, const char *, int, ...);
221
222 /*
223 * Data declarations.
224 */
225 struct r_debug r_debug __exported; /* for GDB; */
226 static bool libmap_disable; /* Disable libmap */
227 static bool ld_loadfltr; /* Immediate filters processing */
228 static const char *libmap_override; /* Maps to use in addition to libmap.conf */
229 static bool trust; /* False for setuid and setgid programs */
230 static bool dangerous_ld_env; /* True if environment variables have been
231 used to affect the libraries loaded */
232 bool ld_bind_not; /* Disable PLT update */
233 static const char *ld_bind_now; /* Environment variable for immediate binding */
234 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides
235 weak definition */
236 static const char *ld_library_path; /* Environment variable for search path */
237 static const char
238 *ld_library_dirs; /* Environment variable for library descriptors */
239 static const char *ld_preload; /* Environment variable for libraries to
240 load first */
241 static const char *ld_preload_fds; /* Environment variable for libraries
242 represented by descriptors */
243 static const char
244 *ld_elf_hints_path; /* Environment variable for alternative hints path */
245 static const char *ld_tracing; /* Called from ldd to print libs */
246 static const char *ld_utrace; /* Use utrace() to log events. */
247 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
248 static Obj_Entry *obj_main; /* The main program shared object */
249 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
250 static unsigned int obj_count; /* Number of objects in obj_list */
251 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
252 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */
253 RTLD_STATIC_TLS_EXTRA;
254
255 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
256 STAILQ_HEAD_INITIALIZER(list_global);
257 static Objlist list_main = /* Objects loaded at program startup */
258 STAILQ_HEAD_INITIALIZER(list_main);
259 static Objlist list_fini = /* Objects needing fini() calls */
260 STAILQ_HEAD_INITIALIZER(list_fini);
261
262 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
263
264 #define GDB_STATE(s, m) \
265 r_debug.r_state = s; \
266 r_debug_state(&r_debug, m);
267
268 extern Elf_Dyn _DYNAMIC;
269 #pragma weak _DYNAMIC
270
271 int dlclose(void *) __exported;
272 char *dlerror(void) __exported;
273 void *dlopen(const char *, int) __exported;
274 void *fdlopen(int, int) __exported;
275 void *dlsym(void *, const char *) __exported;
276 dlfunc_t dlfunc(void *, const char *) __exported;
277 void *dlvsym(void *, const char *, const char *) __exported;
278 int dladdr(const void *, Dl_info *) __exported;
279 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
280 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
281 int dlinfo(void *, int, void *) __exported;
282 int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback, void *) __exported;
283 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
284 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
285 int _rtld_get_stack_prot(void) __exported;
286 int _rtld_is_dlopened(void *) __exported;
287 void _rtld_error(const char *, ...) __exported;
288 const char *rtld_get_var(const char *name) __exported;
289 int rtld_set_var(const char *name, const char *val) __exported;
290
291 /* Only here to fix -Wmissing-prototypes warnings */
292 int __getosreldate(void);
293 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
294 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
295
296 int npagesizes;
297 static int osreldate;
298 size_t *pagesizes;
299 size_t page_size;
300
301 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
302 static int max_stack_flags;
303
304 /*
305 * Global declarations normally provided by crt1. The dynamic linker is
306 * not built with crt1, so we have to provide them ourselves.
307 */
308 char *__progname;
309 char **environ;
310
311 /*
312 * Used to pass argc, argv to init functions.
313 */
314 int main_argc;
315 char **main_argv;
316
317 /*
318 * Globals to control TLS allocation.
319 */
320 size_t tls_last_offset; /* Static TLS offset of last module */
321 size_t tls_last_size; /* Static TLS size of last module */
322 size_t tls_static_space; /* Static TLS space allocated */
323 static size_t tls_static_max_align;
324 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
325 int tls_max_index = 1; /* Largest module index allocated */
326
327 static TAILQ_HEAD(, tcb_list_entry) tcb_list =
328 TAILQ_HEAD_INITIALIZER(tcb_list);
329 static size_t tcb_list_entry_offset;
330
331 static bool ld_library_path_rpath = false;
332 bool ld_fast_sigblock = false;
333
334 /*
335 * Globals for path names, and such
336 */
337 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
338 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
339 const char *ld_path_rtld = _PATH_RTLD;
340 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
341 const char *ld_env_prefix = LD_;
342
343 static void (*rtld_exit_ptr)(void);
344
345 #define LD_UTRACE(e, h, mb, ms, r, n) \
346 do { \
347 if (ld_utrace != NULL) \
348 ld_utrace_log(e, h, mb, ms, r, n); \
349 } while (0)
350
351 static void
ld_utrace_log(int event,void * handle,void * mapbase,size_t mapsize,int refcnt,const char * name)352 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
353 int refcnt, const char *name)
354 {
355 struct utrace_rtld ut;
356 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] __nonstring =
357 RTLD_UTRACE_SIG;
358
359 memset(&ut, 0, sizeof(ut)); /* clear holes */
360 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
361 ut.event = event;
362 ut.handle = handle;
363 ut.mapbase = mapbase;
364 ut.mapsize = mapsize;
365 ut.refcnt = refcnt;
366 if (name != NULL)
367 strlcpy(ut.name, name, sizeof(ut.name));
368 utrace(&ut, sizeof(ut));
369 }
370
371 struct ld_env_var_desc {
372 const char *const n;
373 const char *val;
374 const bool unsecure : 1;
375 const bool can_update : 1;
376 bool owned : 1;
377 void (*const on_update)(struct ld_env_var_desc *);
378 };
379 #define LD_ENV_DESC(var, unsec, ...) \
380 [LD_##var] = { .n = #var, .unsecure = unsec, __VA_ARGS__ }
381
382 static struct ld_env_var_desc ld_env_vars[] = {
383 LD_ENV_DESC(BIND_NOW, false, .can_update = true,
384 .on_update = rtld_set_var_bind_now),
385 LD_ENV_DESC(PRELOAD, true),
386 LD_ENV_DESC(LIBMAP, true),
387 LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true,
388 .on_update = rtld_set_var_library_path),
389 LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true,
390 .on_update = rtld_set_var_library_path_fds),
391 LD_ENV_DESC(LIBMAP_DISABLE, true, .can_update = true,
392 .on_update = rtld_set_var_libmap_disable),
393 LD_ENV_DESC(BIND_NOT, true, .can_update = true,
394 .on_update = rtld_set_var_bind_not),
395 LD_ENV_DESC(DEBUG, true, .can_update = true,
396 .on_update = rtld_set_var_debug),
397 LD_ENV_DESC(ELF_HINTS_PATH, true),
398 LD_ENV_DESC(LOADFLTR, true, .can_update = true,
399 .on_update = rtld_set_var_loadfltr),
400 LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true,
401 .on_update = rtld_set_var_library_path_rpath),
402 LD_ENV_DESC(PRELOAD_FDS, true),
403 LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true,
404 .on_update = rtld_set_var_dynamic_weak),
405 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false),
406 LD_ENV_DESC(UTRACE, false, .can_update = true),
407 LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true),
408 LD_ENV_DESC(DUMP_REL_POST, false, .can_update = true),
409 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false),
410 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false),
411 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false),
412 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false),
413 LD_ENV_DESC(SHOW_AUXV, true),
414 LD_ENV_DESC(STATIC_TLS_EXTRA, false),
415 LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false),
416 };
417
418 const char *
ld_get_env_var(int idx)419 ld_get_env_var(int idx)
420 {
421 return (ld_env_vars[idx].val);
422 }
423
424 static const char *
rtld_get_env_val(char ** env,const char * name,size_t name_len)425 rtld_get_env_val(char **env, const char *name, size_t name_len)
426 {
427 char **m, *n, *v;
428
429 for (m = env; *m != NULL; m++) {
430 n = *m;
431 v = strchr(n, '=');
432 if (v == NULL) {
433 /* corrupt environment? */
434 continue;
435 }
436 if (v - n == (ptrdiff_t)name_len &&
437 strncmp(name, n, name_len) == 0)
438 return (v + 1);
439 }
440 return (NULL);
441 }
442
443 static void
rtld_init_env_vars_for_prefix(char ** env,const char * env_prefix)444 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix)
445 {
446 struct ld_env_var_desc *lvd;
447 size_t prefix_len, nlen;
448 char **m, *n, *v;
449 int i;
450
451 prefix_len = strlen(env_prefix);
452 for (m = env; *m != NULL; m++) {
453 n = *m;
454 if (strncmp(env_prefix, n, prefix_len) != 0) {
455 /* Not a rtld environment variable. */
456 continue;
457 }
458 n += prefix_len;
459 v = strchr(n, '=');
460 if (v == NULL) {
461 /* corrupt environment? */
462 continue;
463 }
464 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
465 lvd = &ld_env_vars[i];
466 if (lvd->val != NULL) {
467 /* Saw higher-priority variable name already. */
468 continue;
469 }
470 nlen = strlen(lvd->n);
471 if (v - n == (ptrdiff_t)nlen &&
472 strncmp(lvd->n, n, nlen) == 0) {
473 lvd->val = v + 1;
474 break;
475 }
476 }
477 }
478 }
479
480 static void
rtld_init_env_vars(char ** env)481 rtld_init_env_vars(char **env)
482 {
483 rtld_init_env_vars_for_prefix(env, ld_env_prefix);
484 }
485
486 static void
set_ld_elf_hints_path(void)487 set_ld_elf_hints_path(void)
488 {
489 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0)
490 ld_elf_hints_path = ld_elf_hints_default;
491 }
492
493 uintptr_t
rtld_round_page(uintptr_t x)494 rtld_round_page(uintptr_t x)
495 {
496 return (roundup2(x, page_size));
497 }
498
499 uintptr_t
rtld_trunc_page(uintptr_t x)500 rtld_trunc_page(uintptr_t x)
501 {
502 return (rounddown2(x, page_size));
503 }
504
505 /*
506 * Main entry point for dynamic linking. The first argument is the
507 * stack pointer. The stack is expected to be laid out as described
508 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
509 * Specifically, the stack pointer points to a word containing
510 * ARGC. Following that in the stack is a null-terminated sequence
511 * of pointers to argument strings. Then comes a null-terminated
512 * sequence of pointers to environment strings. Finally, there is a
513 * sequence of "auxiliary vector" entries.
514 *
515 * The second argument points to a place to store the dynamic linker's
516 * exit procedure pointer and the third to a place to store the main
517 * program's object.
518 *
519 * The return value is the main program's entry point.
520 */
521 func_ptr_type
_rtld(Elf_Addr * sp,func_ptr_type * exit_proc,Obj_Entry ** objp)522 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
523 {
524 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT], auxtmp;
525 Objlist_Entry *entry;
526 Obj_Entry *last_interposer, *obj, *preload_tail;
527 const Elf_Phdr *phdr;
528 Objlist initlist;
529 RtldLockState lockstate;
530 struct stat st;
531 Elf_Addr *argcp;
532 char **argv, **env, **envp, *kexecpath;
533 const char *argv0, *binpath, *static_tls_extra;
534 struct ld_env_var_desc *lvd;
535 caddr_t imgentry;
536 char buf[MAXPATHLEN];
537 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
538 size_t sz;
539 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path;
540
541 /*
542 * On entry, the dynamic linker itself has not been relocated yet.
543 * Be very careful not to reference any global data until after
544 * init_rtld has returned. It is OK to reference file-scope statics
545 * and string constants, and to call static and global functions.
546 */
547
548 /* Find the auxiliary vector on the stack. */
549 argcp = sp;
550 argc = *sp++;
551 argv = (char **)sp;
552 sp += argc + 1; /* Skip over arguments and NULL terminator */
553 env = (char **)sp;
554 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
555 ;
556 aux = (Elf_Auxinfo *)sp;
557
558 /* Digest the auxiliary vector. */
559 for (i = 0; i < AT_COUNT; i++)
560 aux_info[i] = NULL;
561 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
562 if (auxp->a_type < AT_COUNT)
563 aux_info[auxp->a_type] = auxp;
564 }
565 arch_fix_auxv(aux, aux_info);
566
567 /* Initialize and relocate ourselves. */
568 assert(aux_info[AT_BASE] != NULL);
569 init_rtld((caddr_t)aux_info[AT_BASE]->a_un.a_ptr, aux_info);
570
571 dlerror_dflt_init();
572
573 __progname = obj_rtld.path;
574 argv0 = argv[0] != NULL ? argv[0] : "(null)";
575 environ = env;
576 main_argc = argc;
577 main_argv = argv;
578
579 if (aux_info[AT_BSDFLAGS] != NULL &&
580 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
581 ld_fast_sigblock = true;
582
583 trust = !issetugid();
584 direct_exec = false;
585
586 md_abi_variant_hook(aux_info);
587 rtld_init_env_vars(env);
588
589 fd = -1;
590 if (aux_info[AT_EXECFD] != NULL) {
591 fd = aux_info[AT_EXECFD]->a_un.a_val;
592 } else {
593 assert(aux_info[AT_PHDR] != NULL);
594 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
595 if (phdr == obj_rtld.phdr) {
596 if (!trust) {
597 _rtld_error(
598 "Tainted process refusing to run binary %s",
599 argv0);
600 rtld_die();
601 }
602 direct_exec = true;
603
604 dbg("opening main program in direct exec mode");
605 if (argc >= 2) {
606 rtld_argc = parse_args(argv, argc,
607 &search_in_path, &fd, &argv0, &dir_ignore);
608 explicit_fd = (fd != -1);
609 binpath = NULL;
610 if (!explicit_fd)
611 fd = open_binary_fd(argv0,
612 search_in_path, &binpath);
613 if (fstat(fd, &st) == -1) {
614 _rtld_error(
615 "Failed to fstat FD %d (%s): %s",
616 fd,
617 explicit_fd ?
618 "user-provided descriptor" :
619 argv0,
620 rtld_strerror(errno));
621 rtld_die();
622 }
623
624 /*
625 * Rough emulation of the permission checks done
626 * by execve(2), only Unix DACs are checked,
627 * ACLs are ignored. Preserve the semantic of
628 * disabling owner to execute if owner x bit is
629 * cleared, even if others x bit is enabled.
630 * mmap(2) does not allow to mmap with PROT_EXEC
631 * if binary' file comes from noexec mount. We
632 * cannot set a text reference on the binary.
633 */
634 dir_enable = false;
635 if (st.st_uid == geteuid()) {
636 if ((st.st_mode & S_IXUSR) != 0)
637 dir_enable = true;
638 } else if (st.st_gid == getegid()) {
639 if ((st.st_mode & S_IXGRP) != 0)
640 dir_enable = true;
641 } else if ((st.st_mode & S_IXOTH) != 0) {
642 dir_enable = true;
643 }
644 if (!dir_enable && !dir_ignore) {
645 _rtld_error(
646 "No execute permission for binary %s",
647 argv0);
648 rtld_die();
649 }
650
651 /*
652 * For direct exec mode, argv[0] is the
653 * interpreter name, we must remove it and shift
654 * arguments left before invoking binary main.
655 * Since stack layout places environment
656 * pointers and aux vectors right after the
657 * terminating NULL, we must shift environment
658 * and aux as well.
659 */
660 main_argc = argc - rtld_argc;
661 for (i = 0; i <= main_argc; i++)
662 argv[i] = argv[i + rtld_argc];
663 *argcp -= rtld_argc;
664 environ = env = envp = argv + main_argc + 1;
665 dbg("move env from %p to %p", envp + rtld_argc,
666 envp);
667 do {
668 *envp = *(envp + rtld_argc);
669 } while (*envp++ != NULL);
670 aux = auxp = (Elf_Auxinfo *)envp;
671 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
672 dbg("move aux from %p to %p", auxpf, aux);
673 /*
674 * XXXKIB insert place for AT_EXECPATH if not
675 * present
676 */
677 for (;; auxp++, auxpf++) {
678 /*
679 * NB: Use a temporary since *auxpf and
680 * *auxp overlap if rtld_argc is 1
681 */
682 auxtmp = *auxpf;
683 *auxp = auxtmp;
684 if (auxp->a_type == AT_NULL)
685 break;
686 }
687 /*
688 * Since the auxiliary vector has moved,
689 * redigest it.
690 */
691 for (i = 0; i < AT_COUNT; i++)
692 aux_info[i] = NULL;
693 for (auxp = aux; auxp->a_type != AT_NULL;
694 auxp++) {
695 if (auxp->a_type < AT_COUNT)
696 aux_info[auxp->a_type] = auxp;
697 }
698
699 /*
700 * Point AT_EXECPATH auxv and aux_info to the
701 * binary path.
702 */
703 if (binpath == NULL) {
704 aux_info[AT_EXECPATH] = NULL;
705 } else {
706 if (aux_info[AT_EXECPATH] == NULL) {
707 aux_info[AT_EXECPATH] = xmalloc(
708 sizeof(Elf_Auxinfo));
709 aux_info[AT_EXECPATH]->a_type =
710 AT_EXECPATH;
711 }
712 aux_info[AT_EXECPATH]->a_un.a_ptr =
713 __DECONST(void *, binpath);
714 }
715 } else {
716 _rtld_error("No binary");
717 rtld_die();
718 }
719 }
720 }
721
722 ld_bind_now = ld_get_env_var(LD_BIND_NOW);
723
724 /*
725 * If the process is tainted, then we un-set the dangerous environment
726 * variables. The process will be marked as tainted until setuid(2)
727 * is called. If any child process calls setuid(2) we do not want any
728 * future processes to honor the potentially un-safe variables.
729 */
730 if (!trust) {
731 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
732 lvd = &ld_env_vars[i];
733 if (lvd->unsecure)
734 lvd->val = NULL;
735 }
736 }
737
738 rtld_recalc_debug(ld_get_env_var(LD_DEBUG));
739 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
740 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL;
741 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL;
742 libmap_override = ld_get_env_var(LD_LIBMAP);
743 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH);
744 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS);
745 ld_preload = ld_get_env_var(LD_PRELOAD);
746 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS);
747 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH);
748 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL;
749 rtld_recalc_path_rpath(ld_get_env_var(LD_LIBRARY_PATH_RPATH));
750 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA);
751 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') {
752 sz = parse_integer(static_tls_extra);
753 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX)
754 ld_static_tls_extra = sz;
755 }
756 rtld_recalc_dangerous_ld_env();
757 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS);
758 ld_utrace = ld_get_env_var(LD_UTRACE);
759
760 set_ld_elf_hints_path();
761 dbg("%s is initialized, base address = %p", __progname,
762 (caddr_t)aux_info[AT_BASE]->a_un.a_ptr);
763 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
764 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
765
766 dbg("initializing thread locks");
767 lockdflt_init();
768
769 /*
770 * Load the main program, or process its program header if it is
771 * already loaded.
772 */
773 if (fd != -1) { /* Load the main program. */
774 dbg("loading main program");
775 obj_main = map_object(fd, argv0, NULL, true);
776 close(fd);
777 if (obj_main == NULL)
778 rtld_die();
779 max_stack_flags = obj_main->stack_flags;
780 } else { /* Main program already loaded. */
781 dbg("processing main program's program header");
782 assert(aux_info[AT_PHDR] != NULL);
783 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
784 assert(aux_info[AT_PHNUM] != NULL);
785 phnum = aux_info[AT_PHNUM]->a_un.a_val;
786 assert(aux_info[AT_PHENT] != NULL);
787 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
788 assert(aux_info[AT_ENTRY] != NULL);
789 imgentry = (caddr_t)aux_info[AT_ENTRY]->a_un.a_ptr;
790 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) ==
791 NULL)
792 rtld_die();
793 }
794
795 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
796 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
797 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
798 if (kexecpath[0] == '/')
799 obj_main->path = kexecpath;
800 else if (getcwd(buf, sizeof(buf)) == NULL ||
801 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
802 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
803 obj_main->path = xstrdup(argv0);
804 else
805 obj_main->path = xstrdup(buf);
806 } else {
807 dbg("No AT_EXECPATH or direct exec");
808 obj_main->path = xstrdup(argv0);
809 }
810 dbg("obj_main path %s", obj_main->path);
811 obj_main->mainprog = true;
812
813 if (aux_info[AT_STACKPROT] != NULL &&
814 aux_info[AT_STACKPROT]->a_un.a_val != 0)
815 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
816
817 #ifndef COMPAT_libcompat
818 /*
819 * Get the actual dynamic linker pathname from the executable if
820 * possible. (It should always be possible.) That ensures that
821 * gdb will find the right dynamic linker even if a non-standard
822 * one is being used.
823 */
824 if (obj_main->interp != NULL &&
825 strcmp(obj_main->interp, obj_rtld.path) != 0) {
826 free(obj_rtld.path);
827 obj_rtld.path = xstrdup(obj_main->interp);
828 __progname = obj_rtld.path;
829 }
830 #endif
831
832 if (!digest_dynamic(obj_main, 0))
833 rtld_die();
834 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
835 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
836 obj_main->dynsymcount);
837
838 linkmap_add(obj_main);
839 linkmap_add(&obj_rtld);
840 LD_UTRACE(UTRACE_LOAD_OBJECT, obj_main, obj_main->mapbase,
841 obj_main->mapsize, 0, obj_main->path);
842 LD_UTRACE(UTRACE_LOAD_OBJECT, &obj_rtld, obj_rtld.mapbase,
843 obj_rtld.mapsize, 0, obj_rtld.path);
844
845 /* Link the main program into the list of objects. */
846 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
847 obj_count++;
848 obj_loads++;
849
850 /* Initialize a fake symbol for resolving undefined weak references. */
851 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
852 sym_zero.st_shndx = SHN_UNDEF;
853 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
854
855 if (!libmap_disable)
856 libmap_disable = (bool)lm_init(libmap_override);
857
858 if (aux_info[AT_KPRELOAD] != NULL &&
859 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) {
860 dbg("loading kernel vdso");
861 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1)
862 rtld_die();
863 }
864
865 dbg("loading LD_PRELOAD_FDS libraries");
866 if (load_preload_objects(ld_preload_fds, true) == -1)
867 rtld_die();
868
869 dbg("loading LD_PRELOAD libraries");
870 if (load_preload_objects(ld_preload, false) == -1)
871 rtld_die();
872 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
873
874 dbg("loading needed objects");
875 if (load_needed_objects(obj_main,
876 ld_tracing != NULL ? RTLD_LO_TRACE : 0) == -1)
877 rtld_die();
878
879 /* Make a list of all objects loaded at startup. */
880 last_interposer = obj_main;
881 TAILQ_FOREACH(obj, &obj_list, next) {
882 if (obj->marker)
883 continue;
884 if (obj->z_interpose && obj != obj_main) {
885 objlist_put_after(&list_main, last_interposer, obj);
886 last_interposer = obj;
887 } else {
888 objlist_push_tail(&list_main, obj);
889 }
890 obj->refcount++;
891 }
892
893 dbg("checking for required versions");
894 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
895 rtld_die();
896
897 if (ld_get_env_var(LD_SHOW_AUXV) != NULL)
898 dump_auxv(aux_info);
899
900 if (ld_tracing) { /* We're done */
901 trace_loaded_objects(obj_main, true);
902 exit(0);
903 }
904
905 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) {
906 dump_relocations(obj_main);
907 exit(0);
908 }
909
910 /*
911 * Processing tls relocations requires having the tls offsets
912 * initialized. Prepare offsets before starting initial
913 * relocation processing.
914 */
915 dbg("initializing initial thread local storage offsets");
916 STAILQ_FOREACH(entry, &list_main, link) {
917 /*
918 * Allocate all the initial objects out of the static TLS
919 * block even if they didn't ask for it.
920 */
921 allocate_tls_offset(entry->obj);
922 }
923
924 if (!allocate_tls_offset_common(&tcb_list_entry_offset,
925 sizeof(struct tcb_list_entry), _Alignof(struct tcb_list_entry),
926 0)) {
927 /*
928 * This should be impossible as the static block size is not
929 * yet fixed, but catch and diagnose it failing if that ever
930 * changes or somehow turns out to be false.
931 */
932 _rtld_error("Could not allocate offset for tcb_list_entry");
933 rtld_die();
934 }
935 dbg("tcb_list_entry_offset %zu", tcb_list_entry_offset);
936
937 if (relocate_objects(obj_main,
938 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld,
939 SYMLOOK_EARLY, NULL) == -1)
940 rtld_die();
941
942 dbg("doing copy relocations");
943 if (do_copy_relocations(obj_main) == -1)
944 rtld_die();
945
946 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) {
947 dump_relocations(obj_main);
948 exit(0);
949 }
950
951 ifunc_init(aux_info);
952
953 /*
954 * Setup TLS for main thread. This must be done after the
955 * relocations are processed, since tls initialization section
956 * might be the subject for relocations.
957 */
958 dbg("initializing initial thread local storage");
959 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
960
961 dbg("initializing key program variables");
962 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
963 set_program_var("environ", env);
964 set_program_var("__elf_aux_vector", aux);
965
966 /* Make a list of init functions to call. */
967 objlist_init(&initlist);
968 initlist_for_loaded_obj(globallist_curr(TAILQ_FIRST(&obj_list)),
969 preload_tail, &initlist);
970
971 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
972
973 map_stacks_exec(NULL);
974
975 if (!obj_main->crt_no_init) {
976 /*
977 * Make sure we don't call the main program's init and fini
978 * functions for binaries linked with old crt1 which calls
979 * _init itself.
980 */
981 obj_main->init = obj_main->fini = 0;
982 obj_main->preinit_array = obj_main->init_array =
983 obj_main->fini_array = NULL;
984 }
985
986 if (direct_exec) {
987 /* Set osrel for direct-execed binary */
988 mib[0] = CTL_KERN;
989 mib[1] = KERN_PROC;
990 mib[2] = KERN_PROC_OSREL;
991 mib[3] = getpid();
992 osrel = obj_main->osrel;
993 sz = sizeof(old_osrel);
994 dbg("setting osrel to %d", osrel);
995 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
996 }
997
998 wlock_acquire(rtld_bind_lock, &lockstate);
999
1000 dbg("resolving ifuncs");
1001 if (initlist_objects_ifunc(&initlist,
1002 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
1003 &lockstate) == -1)
1004 rtld_die();
1005
1006 rtld_exit_ptr = rtld_exit;
1007 if (obj_main->crt_no_init)
1008 preinit_main(&lockstate);
1009 objlist_call_init(&initlist, &lockstate);
1010 _r_debug_postinit(&obj_main->linkmap);
1011 objlist_clear(&initlist);
1012 dbg("loading filtees");
1013 TAILQ_FOREACH(obj, &obj_list, next) {
1014 if (obj->marker)
1015 continue;
1016 if (ld_loadfltr || obj->z_loadfltr)
1017 load_filtees(obj, 0, &lockstate);
1018 }
1019
1020 dbg("enforcing main obj relro");
1021 if (obj_enforce_relro(obj_main) == -1)
1022 rtld_die();
1023
1024 lock_release(rtld_bind_lock, &lockstate);
1025
1026 dbg("transferring control to program entry point = %p",
1027 obj_main->entry);
1028
1029 /* Return the exit procedure and the program entry point. */
1030 *exit_proc = rtld_exit_ptr;
1031 *objp = obj_main;
1032 return ((func_ptr_type)obj_main->entry);
1033 }
1034
1035 /*
1036 * Fill in a DoneList with an allocation large enough to hold all of
1037 * the currently-loaded Keep this as a macro since it calls
1038 * alloca and we want that to occur within the scope of the caller.
1039 */
1040 #define DLP_ALLOCA_LIMIT 100 /* 800 bytes on LP64 */
1041 #define donelist_init(_DLP, _REQ) do { \
1042 DoneList *_dlp = _DLP; \
1043 SymLook *_r = _REQ; \
1044 _dlp->num_alloc = obj_count, \
1045 _dlp->req = NULL; \
1046 if (_dlp->num_alloc > DLP_ALLOCA_LIMIT) { \
1047 _dlp->objs = xcalloc(_dlp->num_alloc, sizeof(_dlp->objs[0])); \
1048 if (_r != NULL && _r->donelist_mem == NULL) { \
1049 _r->donelist_mem = _dlp->objs; \
1050 _dlp->req = _r; \
1051 } \
1052 } else { \
1053 _dlp->objs = alloca(_dlp->num_alloc * sizeof(_dlp->objs[0])); \
1054 } \
1055 _dlp->num_used = 0; \
1056 } while (0)
1057
1058 static void
donelist_free(DoneList * dlp)1059 donelist_free(DoneList *dlp)
1060 {
1061 if (dlp->num_alloc > DLP_ALLOCA_LIMIT)
1062 free(dlp->objs);
1063 if (dlp->req != NULL)
1064 dlp->req->donelist_mem = NULL;
1065 }
1066
1067 void *
rtld_resolve_ifunc(const Obj_Entry * obj,const Elf_Sym * def)1068 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
1069 {
1070 void *ptr;
1071 Elf_Addr target;
1072
1073 ptr = (void *)make_function_pointer(def, obj);
1074 target = call_ifunc_resolver(ptr);
1075 return ((void *)target);
1076 }
1077
1078 Elf_Addr
_rtld_bind(Obj_Entry * obj,Elf_Size reloff)1079 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
1080 {
1081 const Elf_Rel *rel;
1082 const Elf_Sym *def;
1083 const Obj_Entry *defobj;
1084 Elf_Addr *where;
1085 Elf_Addr target;
1086 RtldLockState lockstate;
1087
1088 relock:
1089 rlock_acquire(rtld_bind_lock, &lockstate);
1090 if (sigsetjmp(lockstate.env, 0) != 0)
1091 lock_upgrade(rtld_bind_lock, &lockstate);
1092 if (obj->pltrel)
1093 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
1094 else
1095 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
1096
1097 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
1098 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
1099 NULL, &lockstate);
1100 if (def == NULL)
1101 rtld_die();
1102 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
1103 if (lockstate_wlocked(&lockstate)) {
1104 lock_release(rtld_bind_lock, &lockstate);
1105 goto relock;
1106 }
1107 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
1108 } else {
1109 target = (Elf_Addr)(defobj->relocbase + def->st_value);
1110 }
1111
1112 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", defobj->strtab + def->st_name,
1113 obj->path == NULL ? NULL : basename(obj->path), (void *)target,
1114 defobj->path == NULL ? NULL : basename(defobj->path));
1115
1116 /*
1117 * Write the new contents for the jmpslot. Note that depending on
1118 * architecture, the value which we need to return back to the
1119 * lazy binding trampoline may or may not be the target
1120 * address. The value returned from reloc_jmpslot() is the value
1121 * that the trampoline needs.
1122 */
1123 target = reloc_jmpslot(where, target, defobj, obj, rel);
1124 lock_release(rtld_bind_lock, &lockstate);
1125 return (target);
1126 }
1127
1128 /*
1129 * Error reporting function. Use it like printf. If formats the message
1130 * into a buffer, and sets things up so that the next call to dlerror()
1131 * will return the message.
1132 */
1133 void
_rtld_error(const char * fmt,...)1134 _rtld_error(const char *fmt, ...)
1135 {
1136 va_list ap;
1137
1138 va_start(ap, fmt);
1139 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, fmt,
1140 ap);
1141 va_end(ap);
1142 *lockinfo.dlerror_seen() = 0;
1143 dbg("rtld_error: %s", lockinfo.dlerror_loc());
1144 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
1145 }
1146
1147 /*
1148 * Return a dynamically-allocated copy of the current error message, if any.
1149 */
1150 static struct dlerror_save *
errmsg_save(void)1151 errmsg_save(void)
1152 {
1153 struct dlerror_save *res;
1154
1155 res = xmalloc(sizeof(*res));
1156 res->seen = *lockinfo.dlerror_seen();
1157 if (res->seen == 0)
1158 res->msg = xstrdup(lockinfo.dlerror_loc());
1159 return (res);
1160 }
1161
1162 /*
1163 * Restore the current error message from a copy which was previously saved
1164 * by errmsg_save(). The copy is freed.
1165 */
1166 static void
errmsg_restore(struct dlerror_save * saved_msg)1167 errmsg_restore(struct dlerror_save *saved_msg)
1168 {
1169 if (saved_msg == NULL || saved_msg->seen == 1) {
1170 *lockinfo.dlerror_seen() = 1;
1171 } else {
1172 *lockinfo.dlerror_seen() = 0;
1173 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
1174 lockinfo.dlerror_loc_sz);
1175 free(saved_msg->msg);
1176 }
1177 free(saved_msg);
1178 }
1179
1180 static const char *
basename(const char * name)1181 basename(const char *name)
1182 {
1183 const char *p;
1184
1185 p = strrchr(name, '/');
1186 return (p != NULL ? p + 1 : name);
1187 }
1188
1189 static struct utsname uts;
1190
1191 static char *
origin_subst_one(Obj_Entry * obj,char * real,const char * kw,const char * subst,bool may_free)1192 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, const char *subst,
1193 bool may_free)
1194 {
1195 char *p, *p1, *res, *resp;
1196 int subst_len, kw_len, subst_count, old_len, new_len;
1197
1198 kw_len = strlen(kw);
1199
1200 /*
1201 * First, count the number of the keyword occurrences, to
1202 * preallocate the final string.
1203 */
1204 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1205 p1 = strstr(p, kw);
1206 if (p1 == NULL)
1207 break;
1208 }
1209
1210 /*
1211 * If the keyword is not found, just return.
1212 *
1213 * Return non-substituted string if resolution failed. We
1214 * cannot do anything more reasonable, the failure mode of the
1215 * caller is unresolved library anyway.
1216 */
1217 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1218 return (may_free ? real : xstrdup(real));
1219 if (obj != NULL)
1220 subst = obj->origin_path;
1221
1222 /*
1223 * There is indeed something to substitute. Calculate the
1224 * length of the resulting string, and allocate it.
1225 */
1226 subst_len = strlen(subst);
1227 old_len = strlen(real);
1228 new_len = old_len + (subst_len - kw_len) * subst_count;
1229 res = xmalloc(new_len + 1);
1230
1231 /*
1232 * Now, execute the substitution loop.
1233 */
1234 for (p = real, resp = res, *resp = '\0';;) {
1235 p1 = strstr(p, kw);
1236 if (p1 != NULL) {
1237 /* Copy the prefix before keyword. */
1238 memcpy(resp, p, p1 - p);
1239 resp += p1 - p;
1240 /* Keyword replacement. */
1241 memcpy(resp, subst, subst_len);
1242 resp += subst_len;
1243 *resp = '\0';
1244 p = p1 + kw_len;
1245 } else
1246 break;
1247 }
1248
1249 /* Copy to the end of string and finish. */
1250 strcat(resp, p);
1251 if (may_free)
1252 free(real);
1253 return (res);
1254 }
1255
1256 static const struct {
1257 const char *kw;
1258 bool pass_obj;
1259 const char *subst;
1260 } tokens[] = {
1261 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL },
1262 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL },
1263 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname },
1264 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname },
1265 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release },
1266 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release },
1267 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine },
1268 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine },
1269 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB },
1270 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB },
1271 };
1272
1273 static char *
origin_subst(Obj_Entry * obj,const char * real)1274 origin_subst(Obj_Entry *obj, const char *real)
1275 {
1276 char *res;
1277 int i;
1278
1279 if (obj == NULL || !trust)
1280 return (xstrdup(real));
1281 if (uts.sysname[0] == '\0') {
1282 if (uname(&uts) != 0) {
1283 _rtld_error("utsname failed: %d", errno);
1284 return (NULL);
1285 }
1286 }
1287
1288 /* __DECONST is safe here since without may_free real is unchanged */
1289 res = __DECONST(char *, real);
1290 for (i = 0; i < (int)nitems(tokens); i++) {
1291 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, res,
1292 tokens[i].kw, tokens[i].subst, i != 0);
1293 }
1294 return (res);
1295 }
1296
1297 void
rtld_die(void)1298 rtld_die(void)
1299 {
1300 const char *msg = dlerror();
1301
1302 if (msg == NULL)
1303 msg = "Fatal error";
1304 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1305 rtld_fdputstr(STDERR_FILENO, msg);
1306 rtld_fdputchar(STDERR_FILENO, '\n');
1307 _exit(1);
1308 }
1309
1310 /*
1311 * Process a shared object's DYNAMIC section, and save the important
1312 * information in its Obj_Entry structure.
1313 */
1314 static void
digest_dynamic1(Obj_Entry * obj,int early,const Elf_Dyn ** dyn_rpath,const Elf_Dyn ** dyn_soname,const Elf_Dyn ** dyn_runpath)1315 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1316 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1317 {
1318 const Elf_Dyn *dynp;
1319 Needed_Entry **needed_tail = &obj->needed;
1320 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1321 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1322 const Elf_Hashelt *hashtab;
1323 const Elf32_Word *hashval;
1324 Elf32_Word bkt, nmaskwords;
1325 int bloom_size32;
1326 int plttype = DT_REL;
1327
1328 *dyn_rpath = NULL;
1329 *dyn_soname = NULL;
1330 *dyn_runpath = NULL;
1331
1332 obj->bind_now = false;
1333 dynp = obj->dynamic;
1334 if (dynp == NULL)
1335 return;
1336 for (; dynp->d_tag != DT_NULL; dynp++) {
1337 switch (dynp->d_tag) {
1338 case DT_REL:
1339 obj->rel = (const Elf_Rel *)(obj->relocbase +
1340 dynp->d_un.d_ptr);
1341 break;
1342
1343 case DT_RELSZ:
1344 obj->relsize = dynp->d_un.d_val;
1345 break;
1346
1347 case DT_RELENT:
1348 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1349 break;
1350
1351 case DT_JMPREL:
1352 obj->pltrel = (const Elf_Rel *)(obj->relocbase +
1353 dynp->d_un.d_ptr);
1354 break;
1355
1356 case DT_PLTRELSZ:
1357 obj->pltrelsize = dynp->d_un.d_val;
1358 break;
1359
1360 case DT_RELA:
1361 obj->rela = (const Elf_Rela *)(obj->relocbase +
1362 dynp->d_un.d_ptr);
1363 break;
1364
1365 case DT_RELASZ:
1366 obj->relasize = dynp->d_un.d_val;
1367 break;
1368
1369 case DT_RELAENT:
1370 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1371 break;
1372
1373 case DT_RELR:
1374 obj->relr = (const Elf_Relr *)(obj->relocbase +
1375 dynp->d_un.d_ptr);
1376 break;
1377
1378 case DT_RELRSZ:
1379 obj->relrsize = dynp->d_un.d_val;
1380 break;
1381
1382 case DT_RELRENT:
1383 assert(dynp->d_un.d_val == sizeof(Elf_Relr));
1384 break;
1385
1386 case DT_PLTREL:
1387 plttype = dynp->d_un.d_val;
1388 assert(
1389 dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1390 break;
1391
1392 case DT_SYMTAB:
1393 obj->symtab = (const Elf_Sym *)(obj->relocbase +
1394 dynp->d_un.d_ptr);
1395 break;
1396
1397 case DT_SYMENT:
1398 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1399 break;
1400
1401 case DT_STRTAB:
1402 obj->strtab = (const char *)(obj->relocbase +
1403 dynp->d_un.d_ptr);
1404 break;
1405
1406 case DT_STRSZ:
1407 obj->strsize = dynp->d_un.d_val;
1408 break;
1409
1410 case DT_VERNEED:
1411 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1412 dynp->d_un.d_val);
1413 break;
1414
1415 case DT_VERNEEDNUM:
1416 obj->verneednum = dynp->d_un.d_val;
1417 break;
1418
1419 case DT_VERDEF:
1420 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1421 dynp->d_un.d_val);
1422 break;
1423
1424 case DT_VERDEFNUM:
1425 obj->verdefnum = dynp->d_un.d_val;
1426 break;
1427
1428 case DT_VERSYM:
1429 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1430 dynp->d_un.d_val);
1431 break;
1432
1433 case DT_HASH: {
1434 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1435 dynp->d_un.d_ptr);
1436 obj->nbuckets = hashtab[0];
1437 obj->nchains = hashtab[1];
1438 obj->buckets = hashtab + 2;
1439 obj->chains = obj->buckets + obj->nbuckets;
1440 obj->valid_hash_sysv = obj->nbuckets > 0 &&
1441 obj->nchains > 0 && obj->buckets != NULL;
1442 } break;
1443
1444 case DT_GNU_HASH: {
1445 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1446 dynp->d_un.d_ptr);
1447 obj->nbuckets_gnu = hashtab[0];
1448 obj->symndx_gnu = hashtab[1];
1449 nmaskwords = hashtab[2];
1450 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1451 obj->maskwords_bm_gnu = nmaskwords - 1;
1452 obj->shift2_gnu = hashtab[3];
1453 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1454 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1455 obj->chain_zero_gnu = obj->buckets_gnu +
1456 obj->nbuckets_gnu - obj->symndx_gnu;
1457 /* Number of bitmask words is required to be power of 2
1458 */
1459 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1460 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1461 } break;
1462
1463 case DT_NEEDED:
1464 if (!obj->rtld) {
1465 Needed_Entry *nep = NEW(Needed_Entry);
1466 nep->name = dynp->d_un.d_val;
1467 nep->obj = NULL;
1468 nep->next = NULL;
1469
1470 *needed_tail = nep;
1471 needed_tail = &nep->next;
1472 }
1473 break;
1474
1475 case DT_FILTER:
1476 if (!obj->rtld) {
1477 Needed_Entry *nep = NEW(Needed_Entry);
1478 nep->name = dynp->d_un.d_val;
1479 nep->obj = NULL;
1480 nep->next = NULL;
1481
1482 *needed_filtees_tail = nep;
1483 needed_filtees_tail = &nep->next;
1484
1485 if (obj->linkmap.l_refname == NULL)
1486 obj->linkmap.l_refname =
1487 (char *)dynp->d_un.d_val;
1488 }
1489 break;
1490
1491 case DT_AUXILIARY:
1492 if (!obj->rtld) {
1493 Needed_Entry *nep = NEW(Needed_Entry);
1494 nep->name = dynp->d_un.d_val;
1495 nep->obj = NULL;
1496 nep->next = NULL;
1497
1498 *needed_aux_filtees_tail = nep;
1499 needed_aux_filtees_tail = &nep->next;
1500 }
1501 break;
1502
1503 case DT_PLTGOT:
1504 obj->pltgot = (Elf_Addr *)(obj->relocbase +
1505 dynp->d_un.d_ptr);
1506 break;
1507
1508 case DT_TEXTREL:
1509 obj->textrel = true;
1510 break;
1511
1512 case DT_SYMBOLIC:
1513 obj->symbolic = true;
1514 break;
1515
1516 case DT_RPATH:
1517 /*
1518 * We have to wait until later to process this, because
1519 * we might not have gotten the address of the string
1520 * table yet.
1521 */
1522 *dyn_rpath = dynp;
1523 break;
1524
1525 case DT_SONAME:
1526 *dyn_soname = dynp;
1527 break;
1528
1529 case DT_RUNPATH:
1530 *dyn_runpath = dynp;
1531 break;
1532
1533 case DT_INIT:
1534 obj->init = (uintptr_t)(obj->relocbase +
1535 dynp->d_un.d_ptr);
1536 break;
1537
1538 case DT_PREINIT_ARRAY:
1539 obj->preinit_array = (uintptr_t *)(obj->relocbase +
1540 dynp->d_un.d_ptr);
1541 break;
1542
1543 case DT_PREINIT_ARRAYSZ:
1544 obj->preinit_array_num = dynp->d_un.d_val /
1545 sizeof(uintptr_t);
1546 break;
1547
1548 case DT_INIT_ARRAY:
1549 obj->init_array = (uintptr_t *)(obj->relocbase +
1550 dynp->d_un.d_ptr);
1551 break;
1552
1553 case DT_INIT_ARRAYSZ:
1554 obj->init_array_num = dynp->d_un.d_val /
1555 sizeof(uintptr_t);
1556 break;
1557
1558 case DT_FINI:
1559 obj->fini = (uintptr_t)(obj->relocbase +
1560 dynp->d_un.d_ptr);
1561 break;
1562
1563 case DT_FINI_ARRAY:
1564 obj->fini_array = (uintptr_t *)(obj->relocbase +
1565 dynp->d_un.d_ptr);
1566 break;
1567
1568 case DT_FINI_ARRAYSZ:
1569 obj->fini_array_num = dynp->d_un.d_val /
1570 sizeof(uintptr_t);
1571 break;
1572
1573 case DT_DEBUG:
1574 if (!early)
1575 dbg("Filling in DT_DEBUG entry");
1576 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr =
1577 (Elf_Addr)&r_debug;
1578 break;
1579
1580 case DT_FLAGS:
1581 if (dynp->d_un.d_val & DF_ORIGIN)
1582 obj->z_origin = true;
1583 if (dynp->d_un.d_val & DF_SYMBOLIC)
1584 obj->symbolic = true;
1585 if (dynp->d_un.d_val & DF_TEXTREL)
1586 obj->textrel = true;
1587 if (dynp->d_un.d_val & DF_BIND_NOW)
1588 obj->bind_now = true;
1589 if (dynp->d_un.d_val & DF_STATIC_TLS)
1590 obj->static_tls = true;
1591 break;
1592
1593 case DT_FLAGS_1:
1594 if (dynp->d_un.d_val & DF_1_NOOPEN)
1595 obj->z_noopen = true;
1596 if (dynp->d_un.d_val & DF_1_ORIGIN)
1597 obj->z_origin = true;
1598 if (dynp->d_un.d_val & DF_1_GLOBAL)
1599 obj->z_global = true;
1600 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1601 obj->bind_now = true;
1602 if (dynp->d_un.d_val & DF_1_NODELETE)
1603 obj->z_nodelete = true;
1604 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1605 obj->z_loadfltr = true;
1606 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1607 obj->z_interpose = true;
1608 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1609 obj->z_nodeflib = true;
1610 if (dynp->d_un.d_val & DF_1_PIE)
1611 obj->z_pie = true;
1612 if (dynp->d_un.d_val & DF_1_INITFIRST)
1613 obj->z_initfirst = true;
1614 break;
1615
1616 default:
1617 if (arch_digest_dynamic(obj, dynp))
1618 break;
1619
1620 if (!early) {
1621 dbg("Ignoring d_tag %ld = %#lx",
1622 (long)dynp->d_tag, (long)dynp->d_tag);
1623 }
1624 break;
1625 }
1626 }
1627
1628 obj->traced = false;
1629
1630 if (plttype == DT_RELA) {
1631 obj->pltrela = (const Elf_Rela *)obj->pltrel;
1632 obj->pltrel = NULL;
1633 obj->pltrelasize = obj->pltrelsize;
1634 obj->pltrelsize = 0;
1635 }
1636
1637 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1638 if (obj->valid_hash_sysv)
1639 obj->dynsymcount = obj->nchains;
1640 else if (obj->valid_hash_gnu) {
1641 obj->dynsymcount = 0;
1642 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1643 if (obj->buckets_gnu[bkt] == 0)
1644 continue;
1645 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1646 do
1647 obj->dynsymcount++;
1648 while ((*hashval++ & 1u) == 0);
1649 }
1650 obj->dynsymcount += obj->symndx_gnu;
1651 }
1652
1653 if (obj->linkmap.l_refname != NULL)
1654 obj->linkmap.l_refname = obj->strtab +
1655 (unsigned long)obj->linkmap.l_refname;
1656 }
1657
1658 static bool
obj_resolve_origin(Obj_Entry * obj)1659 obj_resolve_origin(Obj_Entry *obj)
1660 {
1661 if (obj->origin_path != NULL)
1662 return (true);
1663 obj->origin_path = xmalloc(PATH_MAX);
1664 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1665 }
1666
1667 static bool
digest_dynamic2(Obj_Entry * obj,const Elf_Dyn * dyn_rpath,const Elf_Dyn * dyn_soname,const Elf_Dyn * dyn_runpath)1668 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1669 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1670 {
1671 if (obj->z_origin && !obj_resolve_origin(obj))
1672 return (false);
1673
1674 if (dyn_runpath != NULL) {
1675 obj->runpath = (const char *)obj->strtab +
1676 dyn_runpath->d_un.d_val;
1677 obj->runpath = origin_subst(obj, obj->runpath);
1678 } else if (dyn_rpath != NULL) {
1679 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1680 obj->rpath = origin_subst(obj, obj->rpath);
1681 }
1682 if (dyn_soname != NULL)
1683 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1684 return (true);
1685 }
1686
1687 static bool
digest_dynamic(Obj_Entry * obj,int early)1688 digest_dynamic(Obj_Entry *obj, int early)
1689 {
1690 const Elf_Dyn *dyn_rpath;
1691 const Elf_Dyn *dyn_soname;
1692 const Elf_Dyn *dyn_runpath;
1693
1694 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1695 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1696 }
1697
1698 /*
1699 * Process a shared object's program header. This is used only for the
1700 * main program, when the kernel has already loaded the main program
1701 * into memory before calling the dynamic linker. It creates and
1702 * returns an Obj_Entry structure.
1703 */
1704 static Obj_Entry *
digest_phdr(const Elf_Phdr * phdr,int phnum,caddr_t entry,const char * path)1705 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1706 {
1707 Obj_Entry *obj;
1708 const Elf_Phdr *phlimit = phdr + phnum;
1709 const Elf_Phdr *ph;
1710 Elf_Addr note_start, note_end;
1711 int nsegs = 0;
1712
1713 obj = obj_new();
1714 for (ph = phdr; ph < phlimit; ph++) {
1715 if (ph->p_type != PT_PHDR)
1716 continue;
1717
1718 obj->phdr = phdr;
1719 obj->phnum = ph->p_memsz / sizeof(*ph);
1720 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1721 break;
1722 }
1723
1724 obj->stack_flags = PF_X | PF_R | PF_W;
1725
1726 for (ph = phdr; ph < phlimit; ph++) {
1727 switch (ph->p_type) {
1728 case PT_INTERP:
1729 obj->interp = (const char *)(ph->p_vaddr +
1730 obj->relocbase);
1731 break;
1732
1733 case PT_LOAD:
1734 if (nsegs == 0) { /* First load segment */
1735 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
1736 obj->mapbase = obj->vaddrbase + obj->relocbase;
1737 } else { /* Last load segment */
1738 obj->mapsize = rtld_round_page(
1739 ph->p_vaddr + ph->p_memsz) -
1740 obj->vaddrbase;
1741 }
1742 nsegs++;
1743 break;
1744
1745 case PT_DYNAMIC:
1746 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr +
1747 obj->relocbase);
1748 break;
1749
1750 case PT_TLS:
1751 if (ph->p_memsz < ph->p_filesz) {
1752 _rtld_error("%s: invalid PT_TLS segment",
1753 path);
1754 return (NULL);
1755 }
1756
1757 obj->tlsindex = 1;
1758 obj->tlssize = ph->p_memsz;
1759 obj->tlsalign = ph->p_align;
1760 obj->tlsinitsize = ph->p_filesz;
1761 obj->tlsinit = (void *)(ph->p_vaddr + obj->relocbase);
1762 obj->tlspoffset = ph->p_offset;
1763 break;
1764
1765 case PT_GNU_STACK:
1766 obj->stack_flags = ph->p_flags;
1767 break;
1768
1769 case PT_NOTE:
1770 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1771 note_end = note_start + ph->p_filesz;
1772 digest_notes(obj, note_start, note_end);
1773 break;
1774 }
1775 }
1776 if (nsegs < 1) {
1777 _rtld_error("%s: too few PT_LOAD segments", path);
1778 return (NULL);
1779 }
1780
1781 obj->entry = entry;
1782 return (obj);
1783 }
1784
1785 void
digest_notes(Obj_Entry * obj,Elf_Addr note_start,Elf_Addr note_end)1786 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1787 {
1788 const Elf_Note *note, *next_note;
1789 const char *note_name;
1790 uintptr_t p;
1791
1792 for (note = (const Elf_Note *)note_start;; note = next_note) {
1793 if ((Elf_Addr)note + sizeof(Elf_Note) > note_end)
1794 break;
1795 next_note = (const Elf_Note *)((const char *)(note + 1) +
1796 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1797 roundup2(note->n_descsz, sizeof(Elf32_Addr)));
1798 if ((Elf_Addr)next_note > note_end)
1799 break;
1800
1801 if (arch_digest_note(obj, note))
1802 continue;
1803
1804 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1805 note->n_descsz != sizeof(int32_t))
1806 continue;
1807 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1808 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1809 note->n_type != NT_FREEBSD_NOINIT_TAG)
1810 continue;
1811 note_name = (const char *)(note + 1);
1812 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1813 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1814 continue;
1815 switch (note->n_type) {
1816 case NT_FREEBSD_ABI_TAG:
1817 /* FreeBSD osrel note */
1818 p = (uintptr_t)(note + 1);
1819 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1820 obj->osrel = *(const int32_t *)(p);
1821 dbg("note osrel %d", obj->osrel);
1822 break;
1823 case NT_FREEBSD_FEATURE_CTL:
1824 /* FreeBSD ABI feature control note */
1825 p = (uintptr_t)(note + 1);
1826 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1827 obj->fctl0 = *(const uint32_t *)(p);
1828 dbg("note fctl0 %#x", obj->fctl0);
1829 break;
1830 case NT_FREEBSD_NOINIT_TAG:
1831 /* FreeBSD 'crt does not call init' note */
1832 obj->crt_no_init = true;
1833 dbg("note crt_no_init");
1834 break;
1835 }
1836 }
1837 }
1838
1839 static Obj_Entry *
dlcheck(void * handle)1840 dlcheck(void *handle)
1841 {
1842 Obj_Entry *obj;
1843
1844 TAILQ_FOREACH(obj, &obj_list, next) {
1845 if (obj == (Obj_Entry *)handle)
1846 break;
1847 }
1848
1849 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1850 _rtld_error("Invalid shared object handle %p", handle);
1851 return (NULL);
1852 }
1853 return (obj);
1854 }
1855
1856 /*
1857 * If the given object is already in the donelist, return true. Otherwise
1858 * add the object to the list and return false.
1859 */
1860 static bool
donelist_check(DoneList * dlp,const Obj_Entry * obj)1861 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1862 {
1863 unsigned int i;
1864
1865 for (i = 0; i < dlp->num_used; i++)
1866 if (dlp->objs[i] == obj)
1867 return (true);
1868 /*
1869 * Our donelist allocation should always be sufficient. But if
1870 * our threads locking isn't working properly, more shared objects
1871 * could have been loaded since we allocated the list. That should
1872 * never happen, but we'll handle it properly just in case it does.
1873 */
1874 if (dlp->num_used < dlp->num_alloc)
1875 dlp->objs[dlp->num_used++] = obj;
1876 return (false);
1877 }
1878
1879 /*
1880 * SysV hash function for symbol table lookup. It is a slightly optimized
1881 * version of the hash specified by the System V ABI.
1882 */
1883 Elf32_Word
elf_hash(const char * name)1884 elf_hash(const char *name)
1885 {
1886 const unsigned char *p = (const unsigned char *)name;
1887 Elf32_Word h = 0;
1888
1889 while (*p != '\0') {
1890 h = (h << 4) + *p++;
1891 h ^= (h >> 24) & 0xf0;
1892 }
1893 return (h & 0x0fffffff);
1894 }
1895
1896 /*
1897 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1898 * unsigned in case it's implemented with a wider type.
1899 */
1900 static uint32_t
gnu_hash(const char * s)1901 gnu_hash(const char *s)
1902 {
1903 uint32_t h;
1904 unsigned char c;
1905
1906 h = 5381;
1907 for (c = *s; c != '\0'; c = *++s)
1908 h = h * 33 + c;
1909 return (h & 0xffffffff);
1910 }
1911
1912 /*
1913 * Find the library with the given name, and return its full pathname.
1914 * The returned string is dynamically allocated. Generates an error
1915 * message and returns NULL if the library cannot be found.
1916 *
1917 * If the second argument is non-NULL, then it refers to an already-
1918 * loaded shared object, whose library search path will be searched.
1919 *
1920 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1921 * descriptor (which is close-on-exec) will be passed out via the third
1922 * argument.
1923 *
1924 * The search order is:
1925 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1926 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1927 * LD_LIBRARY_PATH
1928 * DT_RUNPATH in the referencing file
1929 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1930 * from list)
1931 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1932 *
1933 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1934 */
1935 static char *
find_library(const char * xname,const Obj_Entry * refobj,int * fdp)1936 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1937 {
1938 char *pathname, *refobj_path;
1939 const char *name;
1940 bool nodeflib, objgiven;
1941
1942 objgiven = refobj != NULL;
1943
1944 if (libmap_disable || !objgiven ||
1945 (name = lm_find(refobj->path, xname)) == NULL)
1946 name = xname;
1947
1948 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1949 if (name[0] != '/' && !trust) {
1950 _rtld_error(
1951 "Absolute pathname required for shared object \"%s\"",
1952 name);
1953 return (NULL);
1954 }
1955 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1956 __DECONST(char *, name)));
1957 }
1958
1959 dbg(" Searching for \"%s\"", name);
1960 refobj_path = objgiven ? refobj->path : NULL;
1961
1962 /*
1963 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1964 * back to pre-conforming behaviour if user requested so with
1965 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1966 * nodeflib.
1967 */
1968 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1969 pathname = search_library_path(name, ld_library_path,
1970 refobj_path, fdp);
1971 if (pathname != NULL)
1972 return (pathname);
1973 if (refobj != NULL) {
1974 pathname = search_library_path(name, refobj->rpath,
1975 refobj_path, fdp);
1976 if (pathname != NULL)
1977 return (pathname);
1978 }
1979 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1980 if (pathname != NULL)
1981 return (pathname);
1982 pathname = search_library_path(name, gethints(false),
1983 refobj_path, fdp);
1984 if (pathname != NULL)
1985 return (pathname);
1986 pathname = search_library_path(name, ld_standard_library_path,
1987 refobj_path, fdp);
1988 if (pathname != NULL)
1989 return (pathname);
1990 } else {
1991 nodeflib = objgiven ? refobj->z_nodeflib : false;
1992 if (objgiven) {
1993 pathname = search_library_path(name, refobj->rpath,
1994 refobj->path, fdp);
1995 if (pathname != NULL)
1996 return (pathname);
1997 }
1998 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1999 pathname = search_library_path(name, obj_main->rpath,
2000 refobj_path, fdp);
2001 if (pathname != NULL)
2002 return (pathname);
2003 }
2004 pathname = search_library_path(name, ld_library_path,
2005 refobj_path, fdp);
2006 if (pathname != NULL)
2007 return (pathname);
2008 if (objgiven) {
2009 pathname = search_library_path(name, refobj->runpath,
2010 refobj_path, fdp);
2011 if (pathname != NULL)
2012 return (pathname);
2013 }
2014 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
2015 if (pathname != NULL)
2016 return (pathname);
2017 pathname = search_library_path(name, gethints(nodeflib),
2018 refobj_path, fdp);
2019 if (pathname != NULL)
2020 return (pathname);
2021 if (objgiven && !nodeflib) {
2022 pathname = search_library_path(name,
2023 ld_standard_library_path, refobj_path, fdp);
2024 if (pathname != NULL)
2025 return (pathname);
2026 }
2027 }
2028
2029 if (objgiven && refobj->path != NULL) {
2030 _rtld_error(
2031 "Shared object \"%s\" not found, required by \"%s\"",
2032 name, basename(refobj->path));
2033 } else {
2034 _rtld_error("Shared object \"%s\" not found", name);
2035 }
2036 return (NULL);
2037 }
2038
2039 /*
2040 * Given a symbol number in a referencing object, find the corresponding
2041 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2042 * no definition was found. Returns a pointer to the Obj_Entry of the
2043 * defining object via the reference parameter DEFOBJ_OUT.
2044 */
2045 const Elf_Sym *
find_symdef(unsigned long symnum,const Obj_Entry * refobj,const Obj_Entry ** defobj_out,int flags,SymCache * cache,RtldLockState * lockstate)2046 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
2047 const Obj_Entry **defobj_out, int flags, SymCache *cache,
2048 RtldLockState *lockstate)
2049 {
2050 const Elf_Sym *ref;
2051 const Elf_Sym *def;
2052 const Obj_Entry *defobj;
2053 const Ver_Entry *ve;
2054 SymLook req;
2055 const char *name;
2056 int res;
2057
2058 /*
2059 * If we have already found this symbol, get the information from
2060 * the cache.
2061 */
2062 if (symnum >= refobj->dynsymcount)
2063 return (NULL); /* Bad object */
2064 if (cache != NULL && cache[symnum].sym != NULL) {
2065 *defobj_out = cache[symnum].obj;
2066 return (cache[symnum].sym);
2067 }
2068
2069 ref = refobj->symtab + symnum;
2070 name = refobj->strtab + ref->st_name;
2071 def = NULL;
2072 defobj = NULL;
2073 ve = NULL;
2074
2075 /*
2076 * We don't have to do a full scale lookup if the symbol is local.
2077 * We know it will bind to the instance in this load module; to
2078 * which we already have a pointer (ie ref). By not doing a lookup,
2079 * we not only improve performance, but it also avoids unresolvable
2080 * symbols when local symbols are not in the hash table. This has
2081 * been seen with the ia64 toolchain.
2082 */
2083 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2084 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2085 _rtld_error("%s: Bogus symbol table entry %lu",
2086 refobj->path, symnum);
2087 }
2088 symlook_init(&req, name);
2089 req.flags = flags;
2090 ve = req.ventry = fetch_ventry(refobj, symnum);
2091 req.lockstate = lockstate;
2092 res = symlook_default(&req, refobj);
2093 if (res == 0) {
2094 def = req.sym_out;
2095 defobj = req.defobj_out;
2096 }
2097 } else {
2098 def = ref;
2099 defobj = refobj;
2100 }
2101
2102 /*
2103 * If we found no definition and the reference is weak, treat the
2104 * symbol as having the value zero.
2105 */
2106 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2107 def = &sym_zero;
2108 defobj = obj_main;
2109 }
2110
2111 if (def != NULL) {
2112 *defobj_out = defobj;
2113 /*
2114 * Record the information in the cache to avoid subsequent
2115 * lookups.
2116 */
2117 if (cache != NULL) {
2118 cache[symnum].sym = def;
2119 cache[symnum].obj = defobj;
2120 }
2121 } else {
2122 if (refobj != &obj_rtld)
2123 _rtld_error("%s: Undefined symbol \"%s%s%s\"",
2124 refobj->path, name, ve != NULL ? "@" : "",
2125 ve != NULL ? ve->name : "");
2126 }
2127 return (def);
2128 }
2129
2130 /* Convert between native byte order and forced little resp. big endian. */
2131 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n))
2132
2133 /*
2134 * Return the search path from the ldconfig hints file, reading it if
2135 * necessary. If nostdlib is true, then the default search paths are
2136 * not added to result.
2137 *
2138 * Returns NULL if there are problems with the hints file,
2139 * or if the search path there is empty.
2140 */
2141 static const char *
gethints(bool nostdlib)2142 gethints(bool nostdlib)
2143 {
2144 static char *filtered_path;
2145 static const char *hints;
2146 static struct elfhints_hdr hdr;
2147 struct fill_search_info_args sargs, hargs;
2148 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2149 struct dl_serpath *SLPpath, *hintpath;
2150 char *p;
2151 struct stat hint_stat;
2152 unsigned int SLPndx, hintndx, fndx, fcount;
2153 int fd;
2154 size_t flen;
2155 uint32_t dl;
2156 uint32_t magic; /* Magic number */
2157 uint32_t version; /* File version (1) */
2158 uint32_t strtab; /* Offset of string table in file */
2159 uint32_t dirlist; /* Offset of directory list in string table */
2160 uint32_t dirlistlen; /* strlen(dirlist) */
2161 bool is_le; /* Does the hints file use little endian */
2162 bool skip;
2163
2164 /* First call, read the hints file */
2165 if (hints == NULL) {
2166 /* Keep from trying again in case the hints file is bad. */
2167 hints = "";
2168
2169 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) ==
2170 -1) {
2171 dbg("failed to open hints file \"%s\"",
2172 ld_elf_hints_path);
2173 return (NULL);
2174 }
2175
2176 /*
2177 * Check of hdr.dirlistlen value against type limit
2178 * intends to pacify static analyzers. Further
2179 * paranoia leads to checks that dirlist is fully
2180 * contained in the file range.
2181 */
2182 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) {
2183 dbg("failed to read %lu bytes from hints file \"%s\"",
2184 (u_long)sizeof hdr, ld_elf_hints_path);
2185 cleanup1:
2186 close(fd);
2187 hdr.dirlistlen = 0;
2188 return (NULL);
2189 }
2190 dbg("host byte-order: %s-endian",
2191 le32toh(1) == 1 ? "little" : "big");
2192 dbg("hints file byte-order: %s-endian",
2193 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big");
2194 is_le = /*htole32(1) == 1 || */ hdr.magic ==
2195 htole32(ELFHINTS_MAGIC);
2196 magic = COND_SWAP(hdr.magic);
2197 version = COND_SWAP(hdr.version);
2198 strtab = COND_SWAP(hdr.strtab);
2199 dirlist = COND_SWAP(hdr.dirlist);
2200 dirlistlen = COND_SWAP(hdr.dirlistlen);
2201 if (magic != ELFHINTS_MAGIC) {
2202 dbg("invalid magic number %#08x (expected: %#08x)",
2203 magic, ELFHINTS_MAGIC);
2204 goto cleanup1;
2205 }
2206 if (version != 1) {
2207 dbg("hints file version %d (expected: 1)", version);
2208 goto cleanup1;
2209 }
2210 if (dirlistlen > UINT_MAX / 2) {
2211 dbg("directory list is to long: %d > %d", dirlistlen,
2212 UINT_MAX / 2);
2213 goto cleanup1;
2214 }
2215 if (fstat(fd, &hint_stat) == -1) {
2216 dbg("failed to find length of hints file \"%s\"",
2217 ld_elf_hints_path);
2218 goto cleanup1;
2219 }
2220 dl = strtab;
2221 if (dl + dirlist < dl) {
2222 dbg("invalid string table position %d", dl);
2223 goto cleanup1;
2224 }
2225 dl += dirlist;
2226 if (dl + dirlistlen < dl) {
2227 dbg("invalid directory list offset %d", dirlist);
2228 goto cleanup1;
2229 }
2230 dl += dirlistlen;
2231 if (dl > hint_stat.st_size) {
2232 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)",
2233 ld_elf_hints_path, dl,
2234 (uintmax_t)hint_stat.st_size);
2235 goto cleanup1;
2236 }
2237 p = xmalloc(dirlistlen + 1);
2238 if (pread(fd, p, dirlistlen + 1, strtab + dirlist) !=
2239 (ssize_t)dirlistlen + 1 || p[dirlistlen] != '\0') {
2240 free(p);
2241 dbg(
2242 "failed to read %d bytes starting at %d from hints file \"%s\"",
2243 dirlistlen + 1, strtab + dirlist,
2244 ld_elf_hints_path);
2245 goto cleanup1;
2246 }
2247 hints = p;
2248 close(fd);
2249 }
2250
2251 /*
2252 * If caller agreed to receive list which includes the default
2253 * paths, we are done. Otherwise, if we still did not
2254 * calculated filtered result, do it now.
2255 */
2256 if (!nostdlib)
2257 return (hints[0] != '\0' ? hints : NULL);
2258 if (filtered_path != NULL)
2259 goto filt_ret;
2260
2261 /*
2262 * Obtain the list of all configured search paths, and the
2263 * list of the default paths.
2264 *
2265 * First estimate the size of the results.
2266 */
2267 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2268 smeta.dls_cnt = 0;
2269 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2270 hmeta.dls_cnt = 0;
2271
2272 sargs.request = RTLD_DI_SERINFOSIZE;
2273 sargs.serinfo = &smeta;
2274 hargs.request = RTLD_DI_SERINFOSIZE;
2275 hargs.serinfo = &hmeta;
2276
2277 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2278 &sargs);
2279 path_enumerate(hints, fill_search_info, NULL, &hargs);
2280
2281 SLPinfo = xmalloc(smeta.dls_size);
2282 hintinfo = xmalloc(hmeta.dls_size);
2283
2284 /*
2285 * Next fetch both sets of paths.
2286 */
2287 sargs.request = RTLD_DI_SERINFO;
2288 sargs.serinfo = SLPinfo;
2289 sargs.serpath = &SLPinfo->dls_serpath[0];
2290 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2291
2292 hargs.request = RTLD_DI_SERINFO;
2293 hargs.serinfo = hintinfo;
2294 hargs.serpath = &hintinfo->dls_serpath[0];
2295 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2296
2297 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2298 &sargs);
2299 path_enumerate(hints, fill_search_info, NULL, &hargs);
2300
2301 /*
2302 * Now calculate the difference between two sets, by excluding
2303 * standard paths from the full set.
2304 */
2305 fndx = 0;
2306 fcount = 0;
2307 filtered_path = xmalloc(dirlistlen + 1);
2308 hintpath = &hintinfo->dls_serpath[0];
2309 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2310 skip = false;
2311 SLPpath = &SLPinfo->dls_serpath[0];
2312 /*
2313 * Check each standard path against current.
2314 */
2315 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2316 /* matched, skip the path */
2317 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2318 skip = true;
2319 break;
2320 }
2321 }
2322 if (skip)
2323 continue;
2324 /*
2325 * Not matched against any standard path, add the path
2326 * to result. Separate consequtive paths with ':'.
2327 */
2328 if (fcount > 0) {
2329 filtered_path[fndx] = ':';
2330 fndx++;
2331 }
2332 fcount++;
2333 flen = strlen(hintpath->dls_name);
2334 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2335 fndx += flen;
2336 }
2337 filtered_path[fndx] = '\0';
2338
2339 free(SLPinfo);
2340 free(hintinfo);
2341
2342 filt_ret:
2343 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2344 }
2345
2346 static void
init_dag(Obj_Entry * root)2347 init_dag(Obj_Entry *root)
2348 {
2349 const Needed_Entry *needed;
2350 const Objlist_Entry *elm;
2351 DoneList donelist;
2352
2353 if (root->dag_inited)
2354 return;
2355 donelist_init(&donelist, NULL);
2356
2357 /* Root object belongs to own DAG. */
2358 objlist_push_tail(&root->dldags, root);
2359 objlist_push_tail(&root->dagmembers, root);
2360 donelist_check(&donelist, root);
2361
2362 /*
2363 * Add dependencies of root object to DAG in breadth order
2364 * by exploiting the fact that each new object get added
2365 * to the tail of the dagmembers list.
2366 */
2367 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2368 for (needed = elm->obj->needed; needed != NULL;
2369 needed = needed->next) {
2370 if (needed->obj == NULL ||
2371 donelist_check(&donelist, needed->obj))
2372 continue;
2373 objlist_push_tail(&needed->obj->dldags, root);
2374 objlist_push_tail(&root->dagmembers, needed->obj);
2375 }
2376 }
2377 root->dag_inited = true;
2378 donelist_free(&donelist);
2379 }
2380
2381 static void
init_marker(Obj_Entry * marker)2382 init_marker(Obj_Entry *marker)
2383 {
2384 bzero(marker, sizeof(*marker));
2385 marker->marker = true;
2386 }
2387
2388 Obj_Entry *
globallist_curr(const Obj_Entry * obj)2389 globallist_curr(const Obj_Entry *obj)
2390 {
2391 for (;;) {
2392 if (obj == NULL)
2393 return (NULL);
2394 if (!obj->marker)
2395 return (__DECONST(Obj_Entry *, obj));
2396 obj = TAILQ_PREV(obj, obj_entry_q, next);
2397 }
2398 }
2399
2400 Obj_Entry *
globallist_next(const Obj_Entry * obj)2401 globallist_next(const Obj_Entry *obj)
2402 {
2403 for (;;) {
2404 obj = TAILQ_NEXT(obj, next);
2405 if (obj == NULL)
2406 return (NULL);
2407 if (!obj->marker)
2408 return (__DECONST(Obj_Entry *, obj));
2409 }
2410 }
2411
2412 /* Prevent the object from being unmapped while the bind lock is dropped. */
2413 static void
hold_object(Obj_Entry * obj)2414 hold_object(Obj_Entry *obj)
2415 {
2416 obj->holdcount++;
2417 }
2418
2419 static void
unhold_object(Obj_Entry * obj)2420 unhold_object(Obj_Entry *obj)
2421 {
2422 assert(obj->holdcount > 0);
2423 if (--obj->holdcount == 0 && obj->unholdfree)
2424 release_object(obj);
2425 }
2426
2427 static void
process_z(Obj_Entry * root)2428 process_z(Obj_Entry *root)
2429 {
2430 const Objlist_Entry *elm;
2431 Obj_Entry *obj;
2432
2433 /*
2434 * Walk over object DAG and process every dependent object
2435 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2436 * to grow their own DAG.
2437 *
2438 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2439 * symlook_global() to work.
2440 *
2441 * For DF_1_NODELETE, the DAG should have its reference upped.
2442 */
2443 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2444 obj = elm->obj;
2445 if (obj == NULL)
2446 continue;
2447 if (obj->z_nodelete && !obj->ref_nodel) {
2448 dbg("obj %s -z nodelete", obj->path);
2449 init_dag(obj);
2450 ref_dag(obj);
2451 obj->ref_nodel = true;
2452 }
2453 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2454 dbg("obj %s -z global", obj->path);
2455 objlist_push_tail(&list_global, obj);
2456 init_dag(obj);
2457 }
2458 }
2459 }
2460
2461 static void
parse_rtld_phdr(Obj_Entry * obj)2462 parse_rtld_phdr(Obj_Entry *obj)
2463 {
2464 const Elf_Phdr *ph;
2465 Elf_Addr note_start, note_end;
2466 bool first_seg;
2467
2468 first_seg = true;
2469 obj->stack_flags = PF_X | PF_R | PF_W;
2470 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
2471 switch (ph->p_type) {
2472 case PT_LOAD:
2473 if (first_seg) {
2474 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
2475 first_seg = false;
2476 }
2477 obj->mapsize = rtld_round_page(ph->p_vaddr +
2478 ph->p_memsz) - obj->vaddrbase;
2479 break;
2480 case PT_GNU_STACK:
2481 obj->stack_flags = ph->p_flags;
2482 break;
2483 case PT_NOTE:
2484 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2485 note_end = note_start + ph->p_filesz;
2486 digest_notes(obj, note_start, note_end);
2487 break;
2488 }
2489 }
2490 }
2491
2492 /*
2493 * Initialize the dynamic linker. The argument is the address at which
2494 * the dynamic linker has been mapped into memory. The primary task of
2495 * this function is to relocate the dynamic linker.
2496 */
2497 static void
init_rtld(caddr_t mapbase,Elf_Auxinfo ** aux_info)2498 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2499 {
2500 Obj_Entry objtmp; /* Temporary rtld object */
2501 const Elf_Ehdr *ehdr;
2502 const Elf_Dyn *dyn_rpath;
2503 const Elf_Dyn *dyn_soname;
2504 const Elf_Dyn *dyn_runpath;
2505
2506 /*
2507 * Conjure up an Obj_Entry structure for the dynamic linker.
2508 *
2509 * The "path" member can't be initialized yet because string constants
2510 * cannot yet be accessed. Below we will set it correctly.
2511 */
2512 memset(&objtmp, 0, sizeof(objtmp));
2513 objtmp.path = NULL;
2514 objtmp.rtld = true;
2515 objtmp.mapbase = mapbase;
2516 objtmp.relocbase = mapbase;
2517
2518 objtmp.dynamic = rtld_dynamic(&objtmp);
2519 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2520 assert(objtmp.needed == NULL);
2521 assert(!objtmp.textrel);
2522 /*
2523 * Temporarily put the dynamic linker entry into the object list, so
2524 * that symbols can be found.
2525 */
2526 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2527
2528 ehdr = (Elf_Ehdr *)mapbase;
2529 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2530 objtmp.phnum = ehdr->e_phnum;
2531
2532 /* Initialize the object list. */
2533 TAILQ_INIT(&obj_list);
2534
2535 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2536 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2537
2538 /* The page size is required by the dynamic memory allocator. */
2539 init_pagesizes(aux_info);
2540
2541 if (aux_info[AT_OSRELDATE] != NULL)
2542 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2543
2544 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2545
2546 /* Replace the path with a dynamically allocated copy. */
2547 obj_rtld.path = xstrdup(ld_path_rtld);
2548
2549 parse_rtld_phdr(&obj_rtld);
2550 if (obj_enforce_relro(&obj_rtld) == -1)
2551 rtld_die();
2552
2553 r_debug.r_version = R_DEBUG_VERSION;
2554 r_debug.r_brk = r_debug_state;
2555 r_debug.r_state = RT_CONSISTENT;
2556 r_debug.r_ldbase = obj_rtld.relocbase;
2557 }
2558
2559 /*
2560 * Retrieve the array of supported page sizes. The kernel provides the page
2561 * sizes in increasing order.
2562 */
2563 static void
init_pagesizes(Elf_Auxinfo ** aux_info)2564 init_pagesizes(Elf_Auxinfo **aux_info)
2565 {
2566 static size_t psa[MAXPAGESIZES];
2567 int mib[2];
2568 size_t len, size;
2569
2570 if (aux_info[AT_PAGESIZES] != NULL &&
2571 aux_info[AT_PAGESIZESLEN] != NULL) {
2572 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2573 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2574 } else {
2575 len = 2;
2576 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2577 size = sizeof(psa);
2578 else {
2579 /* As a fallback, retrieve the base page size. */
2580 size = sizeof(psa[0]);
2581 if (aux_info[AT_PAGESZ] != NULL) {
2582 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2583 goto psa_filled;
2584 } else {
2585 mib[0] = CTL_HW;
2586 mib[1] = HW_PAGESIZE;
2587 len = 2;
2588 }
2589 }
2590 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2591 _rtld_error("sysctl for hw.pagesize(s) failed");
2592 rtld_die();
2593 }
2594 psa_filled:
2595 pagesizes = psa;
2596 }
2597 npagesizes = size / sizeof(pagesizes[0]);
2598 /* Discard any invalid entries at the end of the array. */
2599 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2600 npagesizes--;
2601
2602 page_size = pagesizes[0];
2603 }
2604
2605 /*
2606 * Add the init functions from a needed object list (and its recursive
2607 * needed objects) to "list". This is not used directly; it is a helper
2608 * function for initlist_add_objects(). The write lock must be held
2609 * when this function is called.
2610 */
2611 static void
initlist_add_neededs(Needed_Entry * needed,Objlist * list,Objlist * iflist)2612 initlist_add_neededs(Needed_Entry *needed, Objlist *list, Objlist *iflist)
2613 {
2614 /* Recursively process the successor needed objects. */
2615 if (needed->next != NULL)
2616 initlist_add_neededs(needed->next, list, iflist);
2617
2618 /* Process the current needed object. */
2619 if (needed->obj != NULL)
2620 initlist_add_objects(needed->obj, needed->obj, list, iflist);
2621 }
2622
2623 /*
2624 * Scan all of the DAGs rooted in the range of objects from "obj" to
2625 * "tail" and add their init functions to "list". This recurses over
2626 * the DAGs and ensure the proper init ordering such that each object's
2627 * needed libraries are initialized before the object itself. At the
2628 * same time, this function adds the objects to the global finalization
2629 * list "list_fini" in the opposite order. The write lock must be
2630 * held when this function is called.
2631 */
2632 static void
initlist_for_loaded_obj(Obj_Entry * obj,Obj_Entry * tail,Objlist * list)2633 initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2634 {
2635 Objlist iflist; /* initfirst objs and their needed */
2636 Objlist_Entry *tmp;
2637
2638 objlist_init(&iflist);
2639 initlist_add_objects(obj, tail, list, &iflist);
2640
2641 STAILQ_FOREACH(tmp, &iflist, link) {
2642 Obj_Entry *tobj = tmp->obj;
2643
2644 if ((tobj->fini != 0 || tobj->fini_array != NULL) &&
2645 !tobj->on_fini_list) {
2646 objlist_push_tail(&list_fini, tobj);
2647 tobj->on_fini_list = true;
2648 }
2649 }
2650
2651 /*
2652 * This might result in the same object appearing more
2653 * than once on the init list. objlist_call_init()
2654 * uses obj->init_scanned to avoid dup calls.
2655 */
2656 STAILQ_REVERSE(&iflist, Struct_Objlist_Entry, link);
2657 STAILQ_FOREACH(tmp, &iflist, link)
2658 objlist_push_head(list, tmp->obj);
2659
2660 objlist_clear(&iflist);
2661 }
2662
2663 static void
initlist_add_objects(Obj_Entry * obj,Obj_Entry * tail,Objlist * list,Objlist * iflist)2664 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list,
2665 Objlist *iflist)
2666 {
2667 Obj_Entry *nobj;
2668
2669 if (obj->init_done)
2670 return;
2671
2672 if (obj->z_initfirst || list == NULL) {
2673 /*
2674 * Ignore obj->init_scanned. The object might indeed
2675 * already be on the init list, but due to being
2676 * needed by an initfirst object, we must put it at
2677 * the head of the init list. obj->init_done protects
2678 * against double-initialization.
2679 */
2680 if (obj->needed != NULL)
2681 initlist_add_neededs(obj->needed, NULL, iflist);
2682 if (obj->needed_filtees != NULL)
2683 initlist_add_neededs(obj->needed_filtees, NULL,
2684 iflist);
2685 if (obj->needed_aux_filtees != NULL)
2686 initlist_add_neededs(obj->needed_aux_filtees,
2687 NULL, iflist);
2688 objlist_push_tail(iflist, obj);
2689
2690 /* Recursively process the successor objects. */
2691 nobj = globallist_next(obj);
2692 if (nobj != NULL && obj != tail)
2693 initlist_add_objects(nobj, tail, list, iflist);
2694 } else {
2695 if (obj->init_scanned)
2696 return;
2697 obj->init_scanned = true;
2698
2699 /* Recursively process the successor objects. */
2700 nobj = globallist_next(obj);
2701 if (nobj != NULL && obj != tail)
2702 initlist_add_objects(nobj, tail, list, iflist);
2703
2704 /* Recursively process the needed objects. */
2705 if (obj->needed != NULL)
2706 initlist_add_neededs(obj->needed, list, iflist);
2707 if (obj->needed_filtees != NULL)
2708 initlist_add_neededs(obj->needed_filtees, list,
2709 iflist);
2710 if (obj->needed_aux_filtees != NULL)
2711 initlist_add_neededs(obj->needed_aux_filtees, list,
2712 iflist);
2713
2714 /* Add the object to the init list. */
2715 objlist_push_tail(list, obj);
2716
2717 /*
2718 * Add the object to the global fini list in the
2719 * reverse order.
2720 */
2721 if ((obj->fini != 0 || obj->fini_array != NULL) &&
2722 !obj->on_fini_list) {
2723 objlist_push_head(&list_fini, obj);
2724 obj->on_fini_list = true;
2725 }
2726 }
2727 }
2728
2729 static void
free_needed_filtees(Needed_Entry * n,RtldLockState * lockstate)2730 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2731 {
2732 Needed_Entry *needed, *needed1;
2733
2734 for (needed = n; needed != NULL; needed = needed->next) {
2735 if (needed->obj != NULL) {
2736 dlclose_locked(needed->obj, lockstate);
2737 needed->obj = NULL;
2738 }
2739 }
2740 for (needed = n; needed != NULL; needed = needed1) {
2741 needed1 = needed->next;
2742 free(needed);
2743 }
2744 }
2745
2746 static void
unload_filtees(Obj_Entry * obj,RtldLockState * lockstate)2747 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2748 {
2749 free_needed_filtees(obj->needed_filtees, lockstate);
2750 obj->needed_filtees = NULL;
2751 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2752 obj->needed_aux_filtees = NULL;
2753 obj->filtees_loaded = false;
2754 }
2755
2756 static void
load_filtee1(Obj_Entry * obj,Needed_Entry * needed,int flags,RtldLockState * lockstate)2757 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2758 RtldLockState *lockstate)
2759 {
2760 for (; needed != NULL; needed = needed->next) {
2761 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2762 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW :
2763 RTLD_LAZY) | RTLD_LOCAL, lockstate);
2764 }
2765 }
2766
2767 static void
load_filtees(Obj_Entry * obj,int flags,RtldLockState * lockstate)2768 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2769 {
2770 if (obj->filtees_loaded || obj->filtees_loading)
2771 return;
2772 lock_restart_for_upgrade(lockstate);
2773 obj->filtees_loading = true;
2774 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2775 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2776 obj->filtees_loaded = true;
2777 obj->filtees_loading = false;
2778 }
2779
2780 static int
process_needed(Obj_Entry * obj,Needed_Entry * needed,int flags)2781 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2782 {
2783 Obj_Entry *obj1;
2784
2785 for (; needed != NULL; needed = needed->next) {
2786 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1,
2787 obj, flags & ~RTLD_LO_NOLOAD);
2788 if (obj1 == NULL && !ld_tracing &&
2789 (flags & RTLD_LO_FILTEES) == 0)
2790 return (-1);
2791 }
2792 return (0);
2793 }
2794
2795 /*
2796 * Given a shared object, traverse its list of needed objects, and load
2797 * each of them. Returns 0 on success. Generates an error message and
2798 * returns -1 on failure.
2799 */
2800 static int
load_needed_objects(Obj_Entry * first,int flags)2801 load_needed_objects(Obj_Entry *first, int flags)
2802 {
2803 Obj_Entry *obj;
2804
2805 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2806 if (obj->marker)
2807 continue;
2808 if (process_needed(obj, obj->needed, flags) == -1)
2809 return (-1);
2810 }
2811 return (0);
2812 }
2813
2814 static int
load_preload_objects(const char * penv,bool isfd)2815 load_preload_objects(const char *penv, bool isfd)
2816 {
2817 Obj_Entry *obj;
2818 const char *name;
2819 size_t len;
2820 char savech, *p, *psave;
2821 int fd;
2822 static const char delim[] = " \t:;";
2823
2824 if (penv == NULL)
2825 return (0);
2826
2827 p = psave = xstrdup(penv);
2828 p += strspn(p, delim);
2829 while (*p != '\0') {
2830 len = strcspn(p, delim);
2831
2832 savech = p[len];
2833 p[len] = '\0';
2834 if (isfd) {
2835 name = NULL;
2836 fd = parse_integer(p);
2837 if (fd == -1) {
2838 free(psave);
2839 return (-1);
2840 }
2841 } else {
2842 name = p;
2843 fd = -1;
2844 }
2845
2846 obj = load_object(name, fd, NULL, 0);
2847 if (obj == NULL) {
2848 free(psave);
2849 return (-1); /* XXX - cleanup */
2850 }
2851 obj->z_interpose = true;
2852 p[len] = savech;
2853 p += len;
2854 p += strspn(p, delim);
2855 }
2856 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2857
2858 free(psave);
2859 return (0);
2860 }
2861
2862 static const char *
printable_path(const char * path)2863 printable_path(const char *path)
2864 {
2865 return (path == NULL ? "<unknown>" : path);
2866 }
2867
2868 /*
2869 * Load a shared object into memory, if it is not already loaded. The
2870 * object may be specified by name or by user-supplied file descriptor
2871 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2872 * duplicate is.
2873 *
2874 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2875 * on failure.
2876 */
2877 static Obj_Entry *
load_object(const char * name,int fd_u,const Obj_Entry * refobj,int flags)2878 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2879 {
2880 Obj_Entry *obj;
2881 int fd;
2882 struct stat sb;
2883 char *path;
2884
2885 fd = -1;
2886 if (name != NULL) {
2887 TAILQ_FOREACH(obj, &obj_list, next) {
2888 if (obj->marker || obj->doomed)
2889 continue;
2890 if (object_match_name(obj, name))
2891 return (obj);
2892 }
2893
2894 path = find_library(name, refobj, &fd);
2895 if (path == NULL)
2896 return (NULL);
2897 } else
2898 path = NULL;
2899
2900 if (fd >= 0) {
2901 /*
2902 * search_library_pathfds() opens a fresh file descriptor for
2903 * the library, so there is no need to dup().
2904 */
2905 } else if (fd_u == -1) {
2906 /*
2907 * If we didn't find a match by pathname, or the name is not
2908 * supplied, open the file and check again by device and inode.
2909 * This avoids false mismatches caused by multiple links or ".."
2910 * in pathnames.
2911 *
2912 * To avoid a race, we open the file and use fstat() rather than
2913 * using stat().
2914 */
2915 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2916 fd = try_fds_open(path, ld_library_dirs);
2917 if (fd == -1) {
2918 _rtld_error("Cannot open \"%s\"", path);
2919 free(path);
2920 return (NULL);
2921 }
2922 }
2923 } else {
2924 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2925 if (fd == -1) {
2926 _rtld_error("Cannot dup fd");
2927 free(path);
2928 return (NULL);
2929 }
2930 }
2931 if (fstat(fd, &sb) == -1) {
2932 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2933 close(fd);
2934 free(path);
2935 return (NULL);
2936 }
2937 TAILQ_FOREACH(obj, &obj_list, next) {
2938 if (obj->marker || obj->doomed)
2939 continue;
2940 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2941 break;
2942 }
2943 if (obj != NULL) {
2944 if (name != NULL)
2945 object_add_name(obj, name);
2946 free(path);
2947 close(fd);
2948 return (obj);
2949 }
2950 if (flags & RTLD_LO_NOLOAD) {
2951 free(path);
2952 close(fd);
2953 return (NULL);
2954 }
2955
2956 /* First use of this object, so we must map it in */
2957 obj = do_load_object(fd, name, path, &sb, flags);
2958 if (obj == NULL)
2959 free(path);
2960 close(fd);
2961
2962 return (obj);
2963 }
2964
2965 static Obj_Entry *
do_load_object(int fd,const char * name,char * path,struct stat * sbp,int flags)2966 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2967 int flags)
2968 {
2969 Obj_Entry *obj;
2970 struct statfs fs;
2971
2972 /*
2973 * First, make sure that environment variables haven't been
2974 * used to circumvent the noexec flag on a filesystem.
2975 * We ignore fstatfs(2) failures, since fd might reference
2976 * not a file, e.g. shmfd.
2977 */
2978 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2979 (fs.f_flags & MNT_NOEXEC) != 0) {
2980 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2981 return (NULL);
2982 }
2983
2984 dbg("loading \"%s\"", printable_path(path));
2985 obj = map_object(fd, printable_path(path), sbp, false);
2986 if (obj == NULL)
2987 return (NULL);
2988
2989 /*
2990 * If DT_SONAME is present in the object, digest_dynamic2 already
2991 * added it to the object names.
2992 */
2993 if (name != NULL)
2994 object_add_name(obj, name);
2995 obj->path = path;
2996 if (!digest_dynamic(obj, 0))
2997 goto errp;
2998 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2999 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
3000 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
3001 dbg("refusing to load PIE executable \"%s\"", obj->path);
3002 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
3003 goto errp;
3004 }
3005 if (obj->z_noopen &&
3006 (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == RTLD_LO_DLOPEN) {
3007 dbg("refusing to load non-loadable \"%s\"", obj->path);
3008 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
3009 goto errp;
3010 }
3011
3012 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
3013 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3014 obj_count++;
3015 obj_loads++;
3016 linkmap_add(obj); /* for GDB & dlinfo() */
3017 max_stack_flags |= obj->stack_flags;
3018
3019 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1,
3020 obj->path);
3021 if (obj->textrel)
3022 dbg(" WARNING: %s has impure text", obj->path);
3023 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3024 obj->path);
3025
3026 return (obj);
3027
3028 errp:
3029 munmap(obj->mapbase, obj->mapsize);
3030 obj->path = NULL; /* obj->path is owned and freed by caller */
3031 obj_free(obj);
3032 return (NULL);
3033 }
3034
3035 static int
load_kpreload(const void * addr)3036 load_kpreload(const void *addr)
3037 {
3038 Obj_Entry *obj;
3039 const Elf_Ehdr *ehdr;
3040 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
3041 static const char kname[] = "[vdso]";
3042
3043 ehdr = addr;
3044 if (!check_elf_headers(ehdr, "kpreload"))
3045 return (-1);
3046 obj = obj_new();
3047 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
3048 obj->phdr = phdr;
3049 obj->phnum = ehdr->e_phnum;
3050 phlimit = phdr + ehdr->e_phnum;
3051 seg0 = segn = NULL;
3052
3053 for (; phdr < phlimit; phdr++) {
3054 switch (phdr->p_type) {
3055 case PT_DYNAMIC:
3056 phdyn = phdr;
3057 break;
3058 case PT_GNU_STACK:
3059 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
3060 obj->stack_flags = phdr->p_flags;
3061 break;
3062 case PT_LOAD:
3063 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
3064 seg0 = phdr;
3065 if (segn == NULL ||
3066 segn->p_vaddr + segn->p_memsz <
3067 phdr->p_vaddr + phdr->p_memsz)
3068 segn = phdr;
3069 break;
3070 }
3071 }
3072
3073 obj->mapbase = __DECONST(caddr_t, addr);
3074 obj->mapsize = segn->p_vaddr + segn->p_memsz;
3075 obj->vaddrbase = 0;
3076 obj->relocbase = obj->mapbase;
3077
3078 object_add_name(obj, kname);
3079 obj->path = xstrdup(kname);
3080 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
3081
3082 if (!digest_dynamic(obj, 0)) {
3083 obj_free(obj);
3084 return (-1);
3085 }
3086
3087 /*
3088 * We assume that kernel-preloaded object does not need
3089 * relocation. It is currently written into read-only page,
3090 * handling relocations would mean we need to allocate at
3091 * least one additional page per AS.
3092 */
3093 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
3094 obj->path, obj->mapbase, obj->phdr, seg0,
3095 obj->relocbase + seg0->p_vaddr, obj->dynamic);
3096
3097 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3098 obj_count++;
3099 obj_loads++;
3100 linkmap_add(obj); /* for GDB & dlinfo() */
3101 max_stack_flags |= obj->stack_flags;
3102
3103 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3104 obj->path);
3105 return (0);
3106 }
3107
3108 Obj_Entry *
obj_from_addr(const void * addr)3109 obj_from_addr(const void *addr)
3110 {
3111 Obj_Entry *obj;
3112
3113 TAILQ_FOREACH(obj, &obj_list, next) {
3114 if (obj->marker)
3115 continue;
3116 if (addr < (void *)obj->mapbase)
3117 continue;
3118 if (addr < (void *)(obj->mapbase + obj->mapsize))
3119 return obj;
3120 }
3121 return (NULL);
3122 }
3123
3124 static void
preinit_main(RtldLockState * lockstate)3125 preinit_main(RtldLockState *lockstate)
3126 {
3127 uintptr_t *preinit_addr;
3128 int index;
3129
3130 preinit_addr = obj_main->preinit_array;
3131 if (preinit_addr == NULL)
3132 return;
3133
3134 lock_release(rtld_bind_lock, lockstate);
3135 for (index = 0; index < obj_main->preinit_array_num; index++) {
3136 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
3137 dbg("calling preinit function for %s at %p",
3138 obj_main->path, (void *)preinit_addr[index]);
3139 LD_UTRACE(UTRACE_INIT_CALL, obj_main,
3140 (void *)preinit_addr[index], 0, 0, obj_main->path);
3141 call_init_pointer(obj_main, preinit_addr[index]);
3142 }
3143 }
3144 wlock_acquire(rtld_bind_lock, lockstate);
3145 }
3146
3147 /*
3148 * Call the finalization functions for each of the objects in "list"
3149 * belonging to the DAG of "root" and referenced once. If NULL "root"
3150 * is specified, every finalization function will be called regardless
3151 * of the reference count and the list elements won't be freed. All of
3152 * the objects are expected to have non-NULL fini functions.
3153 */
3154 static void
objlist_call_fini(Objlist * list,Obj_Entry * root,RtldLockState * lockstate)3155 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
3156 {
3157 Objlist_Entry *elm;
3158 struct dlerror_save *saved_msg;
3159 uintptr_t *fini_addr;
3160 int index;
3161
3162 assert(root == NULL || root->refcount == 1);
3163
3164 if (root != NULL)
3165 root->doomed = true;
3166
3167 /*
3168 * Preserve the current error message since a fini function might
3169 * call into the dynamic linker and overwrite it.
3170 */
3171 saved_msg = errmsg_save();
3172 do {
3173 STAILQ_FOREACH(elm, list, link) {
3174 if (root != NULL &&
3175 (elm->obj->refcount != 1 ||
3176 objlist_find(&root->dagmembers, elm->obj) ==
3177 NULL))
3178 continue;
3179 /* Remove object from fini list to prevent recursive
3180 * invocation. */
3181 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3182 /* Ensure that new references cannot be acquired. */
3183 elm->obj->doomed = true;
3184
3185 hold_object(elm->obj);
3186 lock_release(rtld_bind_lock, lockstate);
3187 /*
3188 * It is legal to have both DT_FINI and DT_FINI_ARRAY
3189 * defined. When this happens, DT_FINI_ARRAY is
3190 * processed first.
3191 */
3192 fini_addr = elm->obj->fini_array;
3193 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
3194 for (index = elm->obj->fini_array_num - 1;
3195 index >= 0; index--) {
3196 if (fini_addr[index] != 0 &&
3197 fini_addr[index] != 1 &&
3198 fini_addr[index] != (Elf_Addr)-1) {
3199 dbg("calling fini function for %s at %p",
3200 elm->obj->path,
3201 (void *)fini_addr[index]);
3202 LD_UTRACE(UTRACE_FINI_CALL,
3203 elm->obj,
3204 (void *)fini_addr[index], 0,
3205 0, elm->obj->path);
3206 call_initfini_pointer(elm->obj,
3207 fini_addr[index]);
3208 }
3209 }
3210 }
3211 if (elm->obj->fini != 0) {
3212 dbg("calling fini function for %s at %p",
3213 elm->obj->path, (void *)elm->obj->fini);
3214 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
3215 (void *)elm->obj->fini, 0, 0,
3216 elm->obj->path);
3217 call_initfini_pointer(elm->obj, elm->obj->fini);
3218 }
3219 wlock_acquire(rtld_bind_lock, lockstate);
3220 unhold_object(elm->obj);
3221 /* No need to free anything if process is going down. */
3222 if (root != NULL)
3223 free(elm);
3224 /*
3225 * We must restart the list traversal after every fini
3226 * call because a dlclose() call from the fini function
3227 * or from another thread might have modified the
3228 * reference counts.
3229 */
3230 break;
3231 }
3232 } while (elm != NULL);
3233 errmsg_restore(saved_msg);
3234 }
3235
3236 /*
3237 * Call the initialization functions for each of the objects in
3238 * "list". All of the objects are expected to have non-NULL init
3239 * functions.
3240 */
3241 static void
objlist_call_init(Objlist * list,RtldLockState * lockstate)3242 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3243 {
3244 Objlist_Entry *elm;
3245 Obj_Entry *obj;
3246 struct dlerror_save *saved_msg;
3247 uintptr_t *init_addr;
3248 void (*reg)(void (*)(void));
3249 int index;
3250
3251 /*
3252 * Clean init_scanned flag so that objects can be rechecked and
3253 * possibly initialized earlier if any of vectors called below
3254 * cause the change by using dlopen.
3255 */
3256 TAILQ_FOREACH(obj, &obj_list, next) {
3257 if (obj->marker)
3258 continue;
3259 obj->init_scanned = false;
3260 }
3261
3262 /*
3263 * Preserve the current error message since an init function might
3264 * call into the dynamic linker and overwrite it.
3265 */
3266 saved_msg = errmsg_save();
3267 STAILQ_FOREACH(elm, list, link) {
3268 if (elm->obj->init_done) /* Initialized early. */
3269 continue;
3270 /*
3271 * Race: other thread might try to use this object before
3272 * current one completes the initialization. Not much can be
3273 * done here without better locking.
3274 */
3275 elm->obj->init_done = true;
3276 hold_object(elm->obj);
3277 reg = NULL;
3278 if (elm->obj == obj_main && obj_main->crt_no_init) {
3279 reg = (void (*)(void (*)(void)))
3280 get_program_var_addr("__libc_atexit", lockstate);
3281 }
3282 lock_release(rtld_bind_lock, lockstate);
3283 if (reg != NULL) {
3284 reg(rtld_exit);
3285 rtld_exit_ptr = rtld_nop_exit;
3286 }
3287
3288 /*
3289 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3290 * When this happens, DT_INIT is processed first.
3291 */
3292 if (elm->obj->init != 0) {
3293 dbg("calling init function for %s at %p",
3294 elm->obj->path, (void *)elm->obj->init);
3295 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3296 (void *)elm->obj->init, 0, 0, elm->obj->path);
3297 call_init_pointer(elm->obj, elm->obj->init);
3298 }
3299 init_addr = elm->obj->init_array;
3300 if (init_addr != NULL) {
3301 for (index = 0; index < elm->obj->init_array_num;
3302 index++) {
3303 if (init_addr[index] != 0 &&
3304 init_addr[index] != 1 &&
3305 init_addr[index] != (Elf_Addr)-1) {
3306 dbg("calling init function for %s at %p",
3307 elm->obj->path,
3308 (void *)init_addr[index]);
3309 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3310 (void *)init_addr[index], 0, 0,
3311 elm->obj->path);
3312 call_init_pointer(elm->obj,
3313 init_addr[index]);
3314 }
3315 }
3316 }
3317 wlock_acquire(rtld_bind_lock, lockstate);
3318 unhold_object(elm->obj);
3319 }
3320 errmsg_restore(saved_msg);
3321 }
3322
3323 static void
objlist_clear(Objlist * list)3324 objlist_clear(Objlist *list)
3325 {
3326 Objlist_Entry *elm;
3327
3328 while (!STAILQ_EMPTY(list)) {
3329 elm = STAILQ_FIRST(list);
3330 STAILQ_REMOVE_HEAD(list, link);
3331 free(elm);
3332 }
3333 }
3334
3335 static Objlist_Entry *
objlist_find(Objlist * list,const Obj_Entry * obj)3336 objlist_find(Objlist *list, const Obj_Entry *obj)
3337 {
3338 Objlist_Entry *elm;
3339
3340 STAILQ_FOREACH(elm, list, link)
3341 if (elm->obj == obj)
3342 return elm;
3343 return (NULL);
3344 }
3345
3346 static void
objlist_init(Objlist * list)3347 objlist_init(Objlist *list)
3348 {
3349 STAILQ_INIT(list);
3350 }
3351
3352 static void
objlist_push_head(Objlist * list,Obj_Entry * obj)3353 objlist_push_head(Objlist *list, Obj_Entry *obj)
3354 {
3355 Objlist_Entry *elm;
3356
3357 elm = NEW(Objlist_Entry);
3358 elm->obj = obj;
3359 STAILQ_INSERT_HEAD(list, elm, link);
3360 }
3361
3362 static void
objlist_push_tail(Objlist * list,Obj_Entry * obj)3363 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3364 {
3365 Objlist_Entry *elm;
3366
3367 elm = NEW(Objlist_Entry);
3368 elm->obj = obj;
3369 STAILQ_INSERT_TAIL(list, elm, link);
3370 }
3371
3372 static void
objlist_put_after(Objlist * list,Obj_Entry * listobj,Obj_Entry * obj)3373 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3374 {
3375 Objlist_Entry *elm, *listelm;
3376
3377 STAILQ_FOREACH(listelm, list, link) {
3378 if (listelm->obj == listobj)
3379 break;
3380 }
3381 elm = NEW(Objlist_Entry);
3382 elm->obj = obj;
3383 if (listelm != NULL)
3384 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3385 else
3386 STAILQ_INSERT_TAIL(list, elm, link);
3387 }
3388
3389 static void
objlist_remove(Objlist * list,Obj_Entry * obj)3390 objlist_remove(Objlist *list, Obj_Entry *obj)
3391 {
3392 Objlist_Entry *elm;
3393
3394 if ((elm = objlist_find(list, obj)) != NULL) {
3395 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3396 free(elm);
3397 }
3398 }
3399
3400 /*
3401 * Relocate dag rooted in the specified object.
3402 * Returns 0 on success, or -1 on failure.
3403 */
3404
3405 static int
relocate_object_dag(Obj_Entry * root,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3406 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3407 int flags, RtldLockState *lockstate)
3408 {
3409 Objlist_Entry *elm;
3410 int error;
3411
3412 error = 0;
3413 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3414 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3415 lockstate);
3416 if (error == -1)
3417 break;
3418 }
3419 return (error);
3420 }
3421
3422 /*
3423 * Prepare for, or clean after, relocating an object marked with
3424 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3425 * segments are remapped read-write. After relocations are done, the
3426 * segment's permissions are returned back to the modes specified in
3427 * the phdrs. If any relocation happened, or always for wired
3428 * program, COW is triggered.
3429 */
3430 static int
reloc_textrel_prot(Obj_Entry * obj,bool before)3431 reloc_textrel_prot(Obj_Entry *obj, bool before)
3432 {
3433 const Elf_Phdr *ph;
3434 void *base;
3435 size_t sz;
3436 int prot;
3437
3438 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
3439 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3440 continue;
3441 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3442 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3443 rtld_trunc_page(ph->p_vaddr);
3444 prot = before ? (PROT_READ | PROT_WRITE) :
3445 convert_prot(ph->p_flags);
3446 if (mprotect(base, sz, prot) == -1) {
3447 _rtld_error("%s: Cannot write-%sable text segment: %s",
3448 obj->path, before ? "en" : "dis",
3449 rtld_strerror(errno));
3450 return (-1);
3451 }
3452 }
3453 return (0);
3454 }
3455
3456 /* Process RELR relative relocations. */
3457 static void
reloc_relr(Obj_Entry * obj)3458 reloc_relr(Obj_Entry *obj)
3459 {
3460 const Elf_Relr *relr, *relrlim;
3461 Elf_Addr *where;
3462
3463 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3464 for (relr = obj->relr; relr < relrlim; relr++) {
3465 Elf_Relr entry = *relr;
3466
3467 if ((entry & 1) == 0) {
3468 where = (Elf_Addr *)(obj->relocbase + entry);
3469 *where++ += (Elf_Addr)obj->relocbase;
3470 } else {
3471 for (long i = 0; (entry >>= 1) != 0; i++)
3472 if ((entry & 1) != 0)
3473 where[i] += (Elf_Addr)obj->relocbase;
3474 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3475 }
3476 }
3477 }
3478
3479 /*
3480 * Relocate single object.
3481 * Returns 0 on success, or -1 on failure.
3482 */
3483 static int
relocate_object(Obj_Entry * obj,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3484 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags,
3485 RtldLockState *lockstate)
3486 {
3487 if (obj->relocated)
3488 return (0);
3489 obj->relocated = true;
3490 if (obj != rtldobj)
3491 dbg("relocating \"%s\"", obj->path);
3492
3493 if (obj->symtab == NULL || obj->strtab == NULL ||
3494 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3495 dbg("object %s has no run-time symbol table", obj->path);
3496
3497 /* There are relocations to the write-protected text segment. */
3498 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3499 return (-1);
3500
3501 /* Process the non-PLT non-IFUNC relocations. */
3502 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3503 return (-1);
3504 reloc_relr(obj);
3505
3506 /* Re-protected the text segment. */
3507 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3508 return (-1);
3509
3510 /* Set the special PLT or GOT entries. */
3511 init_pltgot(obj);
3512
3513 /* Process the PLT relocations. */
3514 if (reloc_plt(obj, flags, lockstate) == -1)
3515 return (-1);
3516 /* Relocate the jump slots if we are doing immediate binding. */
3517 if ((obj->bind_now || bind_now) &&
3518 reloc_jmpslots(obj, flags, lockstate) == -1)
3519 return (-1);
3520
3521 if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1)
3522 return (-1);
3523
3524 /*
3525 * Set up the magic number and version in the Obj_Entry. These
3526 * were checked in the crt1.o from the original ElfKit, so we
3527 * set them for backward compatibility.
3528 */
3529 obj->magic = RTLD_MAGIC;
3530 obj->version = RTLD_VERSION;
3531
3532 return (0);
3533 }
3534
3535 /*
3536 * Relocate newly-loaded shared objects. The argument is a pointer to
3537 * the Obj_Entry for the first such object. All objects from the first
3538 * to the end of the list of objects are relocated. Returns 0 on success,
3539 * or -1 on failure.
3540 */
3541 static int
relocate_objects(Obj_Entry * first,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3542 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, int flags,
3543 RtldLockState *lockstate)
3544 {
3545 Obj_Entry *obj;
3546 int error;
3547
3548 for (error = 0, obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3549 if (obj->marker)
3550 continue;
3551 error = relocate_object(obj, bind_now, rtldobj, flags,
3552 lockstate);
3553 if (error == -1)
3554 break;
3555 }
3556 return (error);
3557 }
3558
3559 /*
3560 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3561 * referencing STT_GNU_IFUNC symbols is postponed till the other
3562 * relocations are done. The indirect functions specified as
3563 * ifunc are allowed to call other symbols, so we need to have
3564 * objects relocated before asking for resolution from indirects.
3565 *
3566 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3567 * instead of the usual lazy handling of PLT slots. It is
3568 * consistent with how GNU does it.
3569 */
3570 static int
resolve_object_ifunc(Obj_Entry * obj,bool bind_now,int flags,RtldLockState * lockstate)3571 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3572 RtldLockState *lockstate)
3573 {
3574 if (obj->ifuncs_resolved)
3575 return (0);
3576 obj->ifuncs_resolved = true;
3577 if (!obj->irelative && !obj->irelative_nonplt &&
3578 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3579 !obj->non_plt_gnu_ifunc)
3580 return (0);
3581 if (obj_disable_relro(obj) == -1 ||
3582 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3583 (obj->irelative_nonplt &&
3584 reloc_iresolve_nonplt(obj, lockstate) == -1) ||
3585 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3586 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3587 (obj->non_plt_gnu_ifunc &&
3588 reloc_non_plt(obj, &obj_rtld, flags | SYMLOOK_IFUNC,
3589 lockstate) == -1) ||
3590 obj_enforce_relro(obj) == -1)
3591 return (-1);
3592 return (0);
3593 }
3594
3595 static int
initlist_objects_ifunc(Objlist * list,bool bind_now,int flags,RtldLockState * lockstate)3596 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3597 RtldLockState *lockstate)
3598 {
3599 Objlist_Entry *elm;
3600 Obj_Entry *obj;
3601
3602 STAILQ_FOREACH(elm, list, link) {
3603 obj = elm->obj;
3604 if (obj->marker)
3605 continue;
3606 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
3607 return (-1);
3608 }
3609 return (0);
3610 }
3611
3612 /*
3613 * Cleanup procedure. It will be called (by the atexit mechanism) just
3614 * before the process exits.
3615 */
3616 static void
rtld_exit(void)3617 rtld_exit(void)
3618 {
3619 RtldLockState lockstate;
3620
3621 wlock_acquire(rtld_bind_lock, &lockstate);
3622 dbg("rtld_exit()");
3623 objlist_call_fini(&list_fini, NULL, &lockstate);
3624 /* No need to remove the items from the list, since we are exiting. */
3625 if (!libmap_disable)
3626 lm_fini();
3627 lock_release(rtld_bind_lock, &lockstate);
3628 }
3629
3630 static void
rtld_nop_exit(void)3631 rtld_nop_exit(void)
3632 {
3633 }
3634
3635 /*
3636 * Parse string of the format '#number/name", where number must be a
3637 * decimal number of the opened file descriptor listed in
3638 * LD_LIBRARY_PATH_FDS. If successful, tries to open dso name under
3639 * dirfd number and returns resulting fd.
3640 * On any error, returns -1.
3641 */
3642 static int
try_fds_open(const char * name,const char * path)3643 try_fds_open(const char *name, const char *path)
3644 {
3645 const char *n;
3646 char *envcopy, *fdstr, *last_token, *ncopy;
3647 size_t len;
3648 int fd, dirfd, dirfd_path;
3649
3650 if (!trust || name[0] != '#' || path == NULL)
3651 return (-1);
3652
3653 name++;
3654 n = strchr(name, '/');
3655 if (n == NULL)
3656 return (-1);
3657 len = n - name;
3658 ncopy = xmalloc(len + 1);
3659 memcpy(ncopy, name, len);
3660 ncopy[len] = '\0';
3661 dirfd = parse_integer(ncopy);
3662 free(ncopy);
3663 if (dirfd == -1)
3664 return (-1);
3665
3666 envcopy = xstrdup(path);
3667 dirfd_path = -1;
3668 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3669 fdstr = strtok_r(NULL, ":", &last_token)) {
3670 dirfd_path = parse_integer(fdstr);
3671 if (dirfd_path == dirfd)
3672 break;
3673 }
3674 free(envcopy);
3675 if (dirfd_path != dirfd)
3676 return (-1);
3677
3678 fd = __sys_openat(dirfd, n + 1, O_RDONLY | O_CLOEXEC | O_VERIFY);
3679 return (fd);
3680 }
3681
3682 /*
3683 * Iterate over a search path, translate each element, and invoke the
3684 * callback on the result.
3685 */
3686 static void *
path_enumerate(const char * path,path_enum_proc callback,const char * refobj_path,void * arg)3687 path_enumerate(const char *path, path_enum_proc callback,
3688 const char *refobj_path, void *arg)
3689 {
3690 const char *trans;
3691 if (path == NULL)
3692 return (NULL);
3693
3694 path += strspn(path, ":;");
3695 while (*path != '\0') {
3696 size_t len;
3697 char *res;
3698
3699 len = strcspn(path, ":;");
3700 trans = lm_findn(refobj_path, path, len);
3701 if (trans)
3702 res = callback(trans, strlen(trans), arg);
3703 else
3704 res = callback(path, len, arg);
3705
3706 if (res != NULL)
3707 return (res);
3708
3709 path += len;
3710 path += strspn(path, ":;");
3711 }
3712
3713 return (NULL);
3714 }
3715
3716 struct try_library_args {
3717 const char *name;
3718 size_t namelen;
3719 char *buffer;
3720 size_t buflen;
3721 int fd;
3722 };
3723
3724 static void *
try_library_path(const char * dir,size_t dirlen,void * param)3725 try_library_path(const char *dir, size_t dirlen, void *param)
3726 {
3727 struct try_library_args *arg;
3728 int fd;
3729
3730 arg = param;
3731 if (*dir == '/' || trust) {
3732 char *pathname;
3733
3734 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3735 return (NULL);
3736
3737 pathname = arg->buffer;
3738 strncpy(pathname, dir, dirlen);
3739 pathname[dirlen] = '/';
3740 strcpy(pathname + dirlen + 1, arg->name);
3741
3742 dbg(" Trying \"%s\"", pathname);
3743 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3744 if (fd >= 0) {
3745 dbg(" Opened \"%s\", fd %d", pathname, fd);
3746 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3747 strcpy(pathname, arg->buffer);
3748 arg->fd = fd;
3749 return (pathname);
3750 } else {
3751 dbg(" Failed to open \"%s\": %s", pathname,
3752 rtld_strerror(errno));
3753 }
3754 }
3755 return (NULL);
3756 }
3757
3758 static char *
search_library_path(const char * name,const char * path,const char * refobj_path,int * fdp)3759 search_library_path(const char *name, const char *path, const char *refobj_path,
3760 int *fdp)
3761 {
3762 char *p;
3763 struct try_library_args arg;
3764
3765 if (path == NULL)
3766 return (NULL);
3767
3768 arg.name = name;
3769 arg.namelen = strlen(name);
3770 arg.buffer = xmalloc(PATH_MAX);
3771 arg.buflen = PATH_MAX;
3772 arg.fd = -1;
3773
3774 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3775 *fdp = arg.fd;
3776
3777 free(arg.buffer);
3778
3779 return (p);
3780 }
3781
3782 /*
3783 * Finds the library with the given name using the directory descriptors
3784 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3785 *
3786 * Returns a freshly-opened close-on-exec file descriptor for the library,
3787 * or -1 if the library cannot be found.
3788 */
3789 static char *
search_library_pathfds(const char * name,const char * path,int * fdp)3790 search_library_pathfds(const char *name, const char *path, int *fdp)
3791 {
3792 char *envcopy, *fdstr, *found, *last_token;
3793 size_t len;
3794 int dirfd, fd;
3795
3796 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3797
3798 /* Don't load from user-specified libdirs into setuid binaries. */
3799 if (!trust)
3800 return (NULL);
3801
3802 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3803 if (path == NULL)
3804 return (NULL);
3805
3806 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3807 if (name[0] == '/') {
3808 dbg("Absolute path (%s) passed to %s", name, __func__);
3809 return (NULL);
3810 }
3811
3812 /*
3813 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3814 * copy of the path, as strtok_r rewrites separator tokens
3815 * with '\0'.
3816 */
3817 found = NULL;
3818 envcopy = xstrdup(path);
3819 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3820 fdstr = strtok_r(NULL, ":", &last_token)) {
3821 dirfd = parse_integer(fdstr);
3822 if (dirfd < 0) {
3823 _rtld_error("failed to parse directory FD: '%s'",
3824 fdstr);
3825 break;
3826 }
3827 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3828 if (fd >= 0) {
3829 *fdp = fd;
3830 len = strlen(fdstr) + strlen(name) + 3;
3831 found = xmalloc(len);
3832 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) <
3833 0) {
3834 _rtld_error("error generating '%d/%s'", dirfd,
3835 name);
3836 rtld_die();
3837 }
3838 dbg("open('%s') => %d", found, fd);
3839 break;
3840 }
3841 }
3842 free(envcopy);
3843
3844 return (found);
3845 }
3846
3847 int
dlclose(void * handle)3848 dlclose(void *handle)
3849 {
3850 RtldLockState lockstate;
3851 int error;
3852
3853 wlock_acquire(rtld_bind_lock, &lockstate);
3854 error = dlclose_locked(handle, &lockstate);
3855 lock_release(rtld_bind_lock, &lockstate);
3856 return (error);
3857 }
3858
3859 static int
dlclose_locked(void * handle,RtldLockState * lockstate)3860 dlclose_locked(void *handle, RtldLockState *lockstate)
3861 {
3862 Obj_Entry *root;
3863
3864 root = dlcheck(handle);
3865 if (root == NULL)
3866 return (-1);
3867 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3868 root->path);
3869
3870 /* Unreference the object and its dependencies. */
3871 root->dl_refcount--;
3872
3873 if (root->refcount == 1) {
3874 /*
3875 * The object will be no longer referenced, so we must unload
3876 * it. First, call the fini functions.
3877 */
3878 objlist_call_fini(&list_fini, root, lockstate);
3879
3880 unref_dag(root);
3881
3882 /* Finish cleaning up the newly-unreferenced objects. */
3883 GDB_STATE(RT_DELETE, &root->linkmap);
3884 unload_object(root, lockstate);
3885 GDB_STATE(RT_CONSISTENT, NULL);
3886 } else
3887 unref_dag(root);
3888
3889 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3890 return (0);
3891 }
3892
3893 char *
dlerror(void)3894 dlerror(void)
3895 {
3896 if (*(lockinfo.dlerror_seen()) != 0)
3897 return (NULL);
3898 *lockinfo.dlerror_seen() = 1;
3899 return (lockinfo.dlerror_loc());
3900 }
3901
3902 /*
3903 * This function is deprecated and has no effect.
3904 */
3905 void
dllockinit(void * context,void * (* _lock_create)(void * context)__unused,void (* _rlock_acquire)(void * lock)__unused,void (* _wlock_acquire)(void * lock)__unused,void (* _lock_release)(void * lock)__unused,void (* _lock_destroy)(void * lock)__unused,void (* context_destroy)(void * context))3906 dllockinit(void *context, void *(*_lock_create)(void *context)__unused,
3907 void (*_rlock_acquire)(void *lock) __unused,
3908 void (*_wlock_acquire)(void *lock) __unused,
3909 void (*_lock_release)(void *lock) __unused,
3910 void (*_lock_destroy)(void *lock) __unused,
3911 void (*context_destroy)(void *context))
3912 {
3913 static void *cur_context;
3914 static void (*cur_context_destroy)(void *);
3915
3916 /* Just destroy the context from the previous call, if necessary. */
3917 if (cur_context_destroy != NULL)
3918 cur_context_destroy(cur_context);
3919 cur_context = context;
3920 cur_context_destroy = context_destroy;
3921 }
3922
3923 void *
dlopen(const char * name,int mode)3924 dlopen(const char *name, int mode)
3925 {
3926 return (rtld_dlopen(name, -1, mode));
3927 }
3928
3929 void *
fdlopen(int fd,int mode)3930 fdlopen(int fd, int mode)
3931 {
3932 return (rtld_dlopen(NULL, fd, mode));
3933 }
3934
3935 static void *
rtld_dlopen(const char * name,int fd,int mode)3936 rtld_dlopen(const char *name, int fd, int mode)
3937 {
3938 RtldLockState lockstate;
3939 int lo_flags;
3940
3941 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3942 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3943 if (ld_tracing != NULL) {
3944 rlock_acquire(rtld_bind_lock, &lockstate);
3945 if (sigsetjmp(lockstate.env, 0) != 0)
3946 lock_upgrade(rtld_bind_lock, &lockstate);
3947 environ = __DECONST(char **,
3948 *get_program_var_addr("environ", &lockstate));
3949 lock_release(rtld_bind_lock, &lockstate);
3950 }
3951 lo_flags = RTLD_LO_DLOPEN;
3952 if (mode & RTLD_NODELETE)
3953 lo_flags |= RTLD_LO_NODELETE;
3954 if (mode & RTLD_NOLOAD)
3955 lo_flags |= RTLD_LO_NOLOAD;
3956 if (mode & RTLD_DEEPBIND)
3957 lo_flags |= RTLD_LO_DEEPBIND;
3958 if (ld_tracing != NULL)
3959 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3960
3961 return (dlopen_object(name, fd, obj_main, lo_flags,
3962 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3963 }
3964
3965 static void
dlopen_cleanup(Obj_Entry * obj,RtldLockState * lockstate)3966 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3967 {
3968 obj->dl_refcount--;
3969 unref_dag(obj);
3970 if (obj->refcount == 0)
3971 unload_object(obj, lockstate);
3972 }
3973
3974 static Obj_Entry *
dlopen_object(const char * name,int fd,Obj_Entry * refobj,int lo_flags,int mode,RtldLockState * lockstate)3975 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3976 int mode, RtldLockState *lockstate)
3977 {
3978 Obj_Entry *obj;
3979 Objlist initlist;
3980 RtldLockState mlockstate;
3981 int result;
3982
3983 dbg(
3984 "dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3985 name != NULL ? name : "<null>", fd,
3986 refobj == NULL ? "<null>" : refobj->path, lo_flags, mode);
3987 objlist_init(&initlist);
3988
3989 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3990 wlock_acquire(rtld_bind_lock, &mlockstate);
3991 lockstate = &mlockstate;
3992 }
3993 GDB_STATE(RT_ADD, NULL);
3994
3995 obj = NULL;
3996 if (name == NULL && fd == -1) {
3997 obj = obj_main;
3998 obj->refcount++;
3999 } else {
4000 obj = load_object(name, fd, refobj, lo_flags);
4001 }
4002
4003 if (obj != NULL) {
4004 obj->dl_refcount++;
4005 if ((mode & RTLD_GLOBAL) != 0 &&
4006 objlist_find(&list_global, obj) == NULL)
4007 objlist_push_tail(&list_global, obj);
4008
4009 if (!obj->init_done) {
4010 /* We loaded something new and have to init something.
4011 */
4012 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
4013 obj->deepbind = true;
4014 result = 0;
4015 if ((lo_flags & (RTLD_LO_EARLY |
4016 RTLD_LO_IGNSTLS)) == 0 &&
4017 obj->static_tls && !allocate_tls_offset(obj)) {
4018 _rtld_error(
4019 "%s: No space available for static Thread Local Storage",
4020 obj->path);
4021 result = -1;
4022 }
4023 if (result != -1)
4024 result = load_needed_objects(obj,
4025 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY |
4026 RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
4027 init_dag(obj);
4028 ref_dag(obj);
4029 if (result != -1)
4030 result = rtld_verify_versions(&obj->dagmembers);
4031 if (result != -1 && ld_tracing)
4032 goto trace;
4033 if (result == -1 || relocate_object_dag(obj,
4034 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
4035 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4036 lockstate) == -1) {
4037 dlopen_cleanup(obj, lockstate);
4038 obj = NULL;
4039 } else if ((lo_flags & RTLD_LO_EARLY) != 0) {
4040 /*
4041 * Do not call the init functions for early
4042 * loaded filtees. The image is still not
4043 * initialized enough for them to work.
4044 *
4045 * Our object is found by the global object list
4046 * and will be ordered among all init calls done
4047 * right before transferring control to main.
4048 */
4049 } else {
4050 /* Make list of init functions to call. */
4051 initlist_for_loaded_obj(obj, obj, &initlist);
4052 }
4053 /*
4054 * Process all no_delete or global objects here, given
4055 * them own DAGs to prevent their dependencies from
4056 * being unloaded. This has to be done after we have
4057 * loaded all of the dependencies, so that we do not
4058 * miss any.
4059 */
4060 if (obj != NULL)
4061 process_z(obj);
4062 } else {
4063 /*
4064 * Bump the reference counts for objects on this DAG. If
4065 * this is the first dlopen() call for the object that
4066 * was already loaded as a dependency, initialize the
4067 * dag starting at it.
4068 */
4069 init_dag(obj);
4070 ref_dag(obj);
4071
4072 if ((lo_flags & RTLD_LO_TRACE) != 0)
4073 goto trace;
4074 }
4075 if (obj != NULL &&
4076 ((lo_flags & RTLD_LO_NODELETE) != 0 || obj->z_nodelete) &&
4077 !obj->ref_nodel) {
4078 dbg("obj %s nodelete", obj->path);
4079 ref_dag(obj);
4080 obj->z_nodelete = obj->ref_nodel = true;
4081 }
4082 }
4083
4084 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
4085 name);
4086 GDB_STATE(RT_CONSISTENT, obj ? &obj->linkmap : NULL);
4087
4088 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4089 map_stacks_exec(lockstate);
4090 if (obj != NULL)
4091 distribute_static_tls(&initlist);
4092 }
4093
4094 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) ==
4095 RTLD_NOW, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4096 lockstate) == -1) {
4097 objlist_clear(&initlist);
4098 dlopen_cleanup(obj, lockstate);
4099 if (lockstate == &mlockstate)
4100 lock_release(rtld_bind_lock, lockstate);
4101 return (NULL);
4102 }
4103
4104 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4105 /* Call the init functions. */
4106 objlist_call_init(&initlist, lockstate);
4107 }
4108 objlist_clear(&initlist);
4109 if (lockstate == &mlockstate)
4110 lock_release(rtld_bind_lock, lockstate);
4111 return (obj);
4112 trace:
4113 trace_loaded_objects(obj, false);
4114 if (lockstate == &mlockstate)
4115 lock_release(rtld_bind_lock, lockstate);
4116 exit(0);
4117 }
4118
4119 static void *
do_dlsym(void * handle,const char * name,void * retaddr,const Ver_Entry * ve,int flags)4120 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
4121 int flags)
4122 {
4123 DoneList donelist;
4124 const Obj_Entry *obj, *defobj;
4125 const Elf_Sym *def;
4126 SymLook req;
4127 RtldLockState lockstate;
4128 tls_index ti;
4129 void *sym;
4130 int res;
4131
4132 def = NULL;
4133 defobj = NULL;
4134 symlook_init(&req, name);
4135 req.ventry = ve;
4136 req.flags = flags | SYMLOOK_IN_PLT;
4137 req.lockstate = &lockstate;
4138
4139 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
4140 rlock_acquire(rtld_bind_lock, &lockstate);
4141 if (sigsetjmp(lockstate.env, 0) != 0) {
4142 lock_upgrade(rtld_bind_lock, &lockstate);
4143 free(req.donelist_mem);
4144 req.donelist_mem = NULL;
4145 }
4146 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT ||
4147 handle == RTLD_SELF) {
4148 if ((obj = obj_from_addr(retaddr)) == NULL) {
4149 _rtld_error("Cannot determine caller's shared object");
4150 lock_release(rtld_bind_lock, &lockstate);
4151 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4152 return (NULL);
4153 }
4154 if (handle == NULL) { /* Just the caller's shared object. */
4155 res = symlook_obj(&req, obj);
4156 if (res == 0) {
4157 def = req.sym_out;
4158 defobj = req.defobj_out;
4159 }
4160 } else if (handle == RTLD_NEXT || /* Objects after caller's */
4161 handle == RTLD_SELF) { /* ... caller included */
4162 if (handle == RTLD_NEXT)
4163 obj = globallist_next(obj);
4164 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4165 if (obj->marker)
4166 continue;
4167 res = symlook_obj(&req, obj);
4168 if (res == 0) {
4169 if (def == NULL ||
4170 (ld_dynamic_weak &&
4171 ELF_ST_BIND(
4172 req.sym_out->st_info) !=
4173 STB_WEAK)) {
4174 def = req.sym_out;
4175 defobj = req.defobj_out;
4176 if (!ld_dynamic_weak ||
4177 ELF_ST_BIND(def->st_info) !=
4178 STB_WEAK)
4179 break;
4180 }
4181 }
4182 }
4183 /*
4184 * Search the dynamic linker itself, and possibly
4185 * resolve the symbol from there. This is how the
4186 * application links to dynamic linker services such as
4187 * dlopen. Note that we ignore ld_dynamic_weak == false
4188 * case, always overriding weak symbols by rtld
4189 * definitions.
4190 */
4191 if (def == NULL ||
4192 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4193 res = symlook_obj(&req, &obj_rtld);
4194 if (res == 0) {
4195 def = req.sym_out;
4196 defobj = req.defobj_out;
4197 }
4198 }
4199 } else {
4200 assert(handle == RTLD_DEFAULT);
4201 res = symlook_default(&req, obj);
4202 if (res == 0) {
4203 defobj = req.defobj_out;
4204 def = req.sym_out;
4205 }
4206 }
4207 } else {
4208 if ((obj = dlcheck(handle)) == NULL) {
4209 lock_release(rtld_bind_lock, &lockstate);
4210 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4211 return (NULL);
4212 }
4213
4214 donelist_init(&donelist, &req);
4215 if (obj->mainprog) {
4216 /* Handle obtained by dlopen(NULL, ...) implies global
4217 * scope. */
4218 res = symlook_global(&req, &donelist);
4219 if (res == 0) {
4220 def = req.sym_out;
4221 defobj = req.defobj_out;
4222 }
4223 /*
4224 * Search the dynamic linker itself, and possibly
4225 * resolve the symbol from there. This is how the
4226 * application links to dynamic linker services such as
4227 * dlopen.
4228 */
4229 if (def == NULL ||
4230 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4231 res = symlook_obj(&req, &obj_rtld);
4232 if (res == 0) {
4233 def = req.sym_out;
4234 defobj = req.defobj_out;
4235 }
4236 }
4237 } else {
4238 /* Search the whole DAG rooted at the given object. */
4239 res = symlook_list(&req, &obj->dagmembers, &donelist);
4240 if (res == 0) {
4241 def = req.sym_out;
4242 defobj = req.defobj_out;
4243 }
4244 }
4245 donelist_free(&donelist);
4246 }
4247
4248 if (def != NULL) {
4249 lock_release(rtld_bind_lock, &lockstate);
4250
4251 /*
4252 * The value required by the caller is derived from the value
4253 * of the symbol. this is simply the relocated value of the
4254 * symbol.
4255 */
4256 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
4257 sym = make_function_pointer(def, defobj);
4258 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
4259 sym = rtld_resolve_ifunc(defobj, def);
4260 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
4261 ti.ti_module = defobj->tlsindex;
4262 ti.ti_offset = def->st_value - TLS_DTV_OFFSET;
4263 sym = __tls_get_addr(&ti);
4264 } else
4265 sym = defobj->relocbase + def->st_value;
4266 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
4267 return (sym);
4268 }
4269
4270 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
4271 ve != NULL ? ve->name : "");
4272 lock_release(rtld_bind_lock, &lockstate);
4273 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4274 return (NULL);
4275 }
4276
4277 void *
dlsym(void * handle,const char * name)4278 dlsym(void *handle, const char *name)
4279 {
4280 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4281 SYMLOOK_DLSYM));
4282 }
4283
4284 dlfunc_t
dlfunc(void * handle,const char * name)4285 dlfunc(void *handle, const char *name)
4286 {
4287 union {
4288 void *d;
4289 dlfunc_t f;
4290 } rv;
4291
4292 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4293 SYMLOOK_DLSYM);
4294 return (rv.f);
4295 }
4296
4297 void *
dlvsym(void * handle,const char * name,const char * version)4298 dlvsym(void *handle, const char *name, const char *version)
4299 {
4300 Ver_Entry ventry;
4301
4302 ventry.name = version;
4303 ventry.file = NULL;
4304 ventry.hash = elf_hash(version);
4305 ventry.flags = 0;
4306 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4307 SYMLOOK_DLSYM));
4308 }
4309
4310 int
_rtld_addr_phdr(const void * addr,struct dl_phdr_info * phdr_info)4311 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4312 {
4313 const Obj_Entry *obj;
4314 RtldLockState lockstate;
4315
4316 rlock_acquire(rtld_bind_lock, &lockstate);
4317 obj = obj_from_addr(addr);
4318 if (obj == NULL) {
4319 _rtld_error("No shared object contains address");
4320 lock_release(rtld_bind_lock, &lockstate);
4321 return (0);
4322 }
4323 rtld_fill_dl_phdr_info(obj, phdr_info);
4324 lock_release(rtld_bind_lock, &lockstate);
4325 return (1);
4326 }
4327
4328 int
dladdr(const void * addr,Dl_info * info)4329 dladdr(const void *addr, Dl_info *info)
4330 {
4331 const Obj_Entry *obj;
4332 const Elf_Sym *def;
4333 void *symbol_addr;
4334 unsigned long symoffset;
4335 RtldLockState lockstate;
4336
4337 rlock_acquire(rtld_bind_lock, &lockstate);
4338 obj = obj_from_addr(addr);
4339 if (obj == NULL) {
4340 _rtld_error("No shared object contains address");
4341 lock_release(rtld_bind_lock, &lockstate);
4342 return (0);
4343 }
4344 info->dli_fname = obj->path;
4345 info->dli_fbase = obj->mapbase;
4346 info->dli_saddr = (void *)0;
4347 info->dli_sname = NULL;
4348
4349 /*
4350 * Walk the symbol list looking for the symbol whose address is
4351 * closest to the address sent in.
4352 */
4353 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4354 def = obj->symtab + symoffset;
4355
4356 /*
4357 * For skip the symbol if st_shndx is either SHN_UNDEF or
4358 * SHN_COMMON.
4359 */
4360 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4361 continue;
4362
4363 /*
4364 * If the symbol is greater than the specified address, or if it
4365 * is further away from addr than the current nearest symbol,
4366 * then reject it.
4367 */
4368 symbol_addr = obj->relocbase + def->st_value;
4369 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4370 continue;
4371
4372 /* Update our idea of the nearest symbol. */
4373 info->dli_sname = obj->strtab + def->st_name;
4374 info->dli_saddr = symbol_addr;
4375
4376 /* Exact match? */
4377 if (info->dli_saddr == addr)
4378 break;
4379 }
4380 lock_release(rtld_bind_lock, &lockstate);
4381 return (1);
4382 }
4383
4384 int
dlinfo(void * handle,int request,void * p)4385 dlinfo(void *handle, int request, void *p)
4386 {
4387 const Obj_Entry *obj;
4388 RtldLockState lockstate;
4389 int error;
4390
4391 rlock_acquire(rtld_bind_lock, &lockstate);
4392
4393 if (handle == NULL || handle == RTLD_SELF) {
4394 void *retaddr;
4395
4396 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4397 if ((obj = obj_from_addr(retaddr)) == NULL)
4398 _rtld_error("Cannot determine caller's shared object");
4399 } else
4400 obj = dlcheck(handle);
4401
4402 if (obj == NULL) {
4403 lock_release(rtld_bind_lock, &lockstate);
4404 return (-1);
4405 }
4406
4407 error = 0;
4408 switch (request) {
4409 case RTLD_DI_LINKMAP:
4410 *((struct link_map const **)p) = &obj->linkmap;
4411 break;
4412 case RTLD_DI_ORIGIN:
4413 error = rtld_dirname(obj->path, p);
4414 break;
4415
4416 case RTLD_DI_SERINFOSIZE:
4417 case RTLD_DI_SERINFO:
4418 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4419 break;
4420
4421 default:
4422 _rtld_error("Invalid request %d passed to dlinfo()", request);
4423 error = -1;
4424 }
4425
4426 lock_release(rtld_bind_lock, &lockstate);
4427
4428 return (error);
4429 }
4430
4431 static void
rtld_fill_dl_phdr_info(const Obj_Entry * obj,struct dl_phdr_info * phdr_info)4432 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4433 {
4434 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4435 phdr_info->dlpi_name = obj->path;
4436 phdr_info->dlpi_phdr = obj->phdr;
4437 phdr_info->dlpi_phnum = obj->phnum;
4438 phdr_info->dlpi_tls_modid = obj->tlsindex;
4439 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(_tcb_get(),
4440 obj->tlsindex, 0, true);
4441 phdr_info->dlpi_adds = obj_loads;
4442 phdr_info->dlpi_subs = obj_loads - obj_count;
4443 }
4444
4445 /*
4446 * It's completely UB to actually use this, so extreme caution is advised. It's
4447 * probably not what you want.
4448 */
4449 int
_dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback,void * param)4450 _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param)
4451 {
4452 struct dl_phdr_info phdr_info;
4453 Obj_Entry *obj;
4454 int error;
4455
4456 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;
4457 obj = globallist_next(obj)) {
4458 rtld_fill_dl_phdr_info(obj, &phdr_info);
4459 error = callback(&phdr_info, sizeof(phdr_info), param);
4460 if (error != 0)
4461 return (error);
4462 }
4463
4464 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4465 return (callback(&phdr_info, sizeof(phdr_info), param));
4466 }
4467
4468 int
dl_iterate_phdr(__dl_iterate_hdr_callback callback,void * param)4469 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4470 {
4471 struct dl_phdr_info phdr_info;
4472 Obj_Entry *obj, marker;
4473 RtldLockState bind_lockstate, phdr_lockstate;
4474 int error;
4475
4476 init_marker(&marker);
4477 error = 0;
4478
4479 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4480 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4481 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4482 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4483 rtld_fill_dl_phdr_info(obj, &phdr_info);
4484 hold_object(obj);
4485 lock_release(rtld_bind_lock, &bind_lockstate);
4486
4487 error = callback(&phdr_info, sizeof phdr_info, param);
4488
4489 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4490 unhold_object(obj);
4491 obj = globallist_next(&marker);
4492 TAILQ_REMOVE(&obj_list, &marker, next);
4493 if (error != 0) {
4494 lock_release(rtld_bind_lock, &bind_lockstate);
4495 lock_release(rtld_phdr_lock, &phdr_lockstate);
4496 return (error);
4497 }
4498 }
4499
4500 if (error == 0) {
4501 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4502 lock_release(rtld_bind_lock, &bind_lockstate);
4503 error = callback(&phdr_info, sizeof(phdr_info), param);
4504 }
4505 lock_release(rtld_phdr_lock, &phdr_lockstate);
4506 return (error);
4507 }
4508
4509 static void *
fill_search_info(const char * dir,size_t dirlen,void * param)4510 fill_search_info(const char *dir, size_t dirlen, void *param)
4511 {
4512 struct fill_search_info_args *arg;
4513
4514 arg = param;
4515
4516 if (arg->request == RTLD_DI_SERINFOSIZE) {
4517 arg->serinfo->dls_cnt++;
4518 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen +
4519 1;
4520 } else {
4521 struct dl_serpath *s_entry;
4522
4523 s_entry = arg->serpath;
4524 s_entry->dls_name = arg->strspace;
4525 s_entry->dls_flags = arg->flags;
4526
4527 strncpy(arg->strspace, dir, dirlen);
4528 arg->strspace[dirlen] = '\0';
4529
4530 arg->strspace += dirlen + 1;
4531 arg->serpath++;
4532 }
4533
4534 return (NULL);
4535 }
4536
4537 static int
do_search_info(const Obj_Entry * obj,int request,struct dl_serinfo * info)4538 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4539 {
4540 struct dl_serinfo _info;
4541 struct fill_search_info_args args;
4542
4543 args.request = RTLD_DI_SERINFOSIZE;
4544 args.serinfo = &_info;
4545
4546 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4547 _info.dls_cnt = 0;
4548
4549 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4550 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4551 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4552 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4553 &args);
4554 if (!obj->z_nodeflib)
4555 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4556 &args);
4557
4558 if (request == RTLD_DI_SERINFOSIZE) {
4559 info->dls_size = _info.dls_size;
4560 info->dls_cnt = _info.dls_cnt;
4561 return (0);
4562 }
4563
4564 if (info->dls_cnt != _info.dls_cnt ||
4565 info->dls_size != _info.dls_size) {
4566 _rtld_error(
4567 "Uninitialized Dl_serinfo struct passed to dlinfo()");
4568 return (-1);
4569 }
4570
4571 args.request = RTLD_DI_SERINFO;
4572 args.serinfo = info;
4573 args.serpath = &info->dls_serpath[0];
4574 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4575
4576 args.flags = LA_SER_RUNPATH;
4577 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4578 return (-1);
4579
4580 args.flags = LA_SER_LIBPATH;
4581 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) !=
4582 NULL)
4583 return (-1);
4584
4585 args.flags = LA_SER_RUNPATH;
4586 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4587 return (-1);
4588
4589 args.flags = LA_SER_CONFIG;
4590 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4591 &args) != NULL)
4592 return (-1);
4593
4594 args.flags = LA_SER_DEFAULT;
4595 if (!obj->z_nodeflib &&
4596 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4597 &args) != NULL)
4598 return (-1);
4599 return (0);
4600 }
4601
4602 static int
rtld_dirname(const char * path,char * bname)4603 rtld_dirname(const char *path, char *bname)
4604 {
4605 const char *endp;
4606
4607 /* Empty or NULL string gets treated as "." */
4608 if (path == NULL || *path == '\0') {
4609 bname[0] = '.';
4610 bname[1] = '\0';
4611 return (0);
4612 }
4613
4614 /* Strip trailing slashes */
4615 endp = path + strlen(path) - 1;
4616 while (endp > path && *endp == '/')
4617 endp--;
4618
4619 /* Find the start of the dir */
4620 while (endp > path && *endp != '/')
4621 endp--;
4622
4623 /* Either the dir is "/" or there are no slashes */
4624 if (endp == path) {
4625 bname[0] = *endp == '/' ? '/' : '.';
4626 bname[1] = '\0';
4627 return (0);
4628 } else {
4629 do {
4630 endp--;
4631 } while (endp > path && *endp == '/');
4632 }
4633
4634 if (endp - path + 2 > PATH_MAX) {
4635 _rtld_error("Filename is too long: %s", path);
4636 return (-1);
4637 }
4638
4639 strncpy(bname, path, endp - path + 1);
4640 bname[endp - path + 1] = '\0';
4641 return (0);
4642 }
4643
4644 static int
rtld_dirname_abs(const char * path,char * base)4645 rtld_dirname_abs(const char *path, char *base)
4646 {
4647 char *last;
4648
4649 if (realpath(path, base) == NULL) {
4650 _rtld_error("realpath \"%s\" failed (%s)", path,
4651 rtld_strerror(errno));
4652 return (-1);
4653 }
4654 dbg("%s -> %s", path, base);
4655 last = strrchr(base, '/');
4656 if (last == NULL) {
4657 _rtld_error("non-abs result from realpath \"%s\"", path);
4658 return (-1);
4659 }
4660 if (last != base)
4661 *last = '\0';
4662 return (0);
4663 }
4664
4665 static void
linkmap_add(Obj_Entry * obj)4666 linkmap_add(Obj_Entry *obj)
4667 {
4668 struct link_map *l, *prev;
4669
4670 l = &obj->linkmap;
4671 l->l_name = obj->path;
4672 l->l_base = obj->mapbase;
4673 l->l_ld = obj->dynamic;
4674 l->l_addr = obj->relocbase;
4675
4676 if (r_debug.r_map == NULL) {
4677 r_debug.r_map = l;
4678 return;
4679 }
4680
4681 /*
4682 * Scan to the end of the list, but not past the entry for the
4683 * dynamic linker, which we want to keep at the very end.
4684 */
4685 for (prev = r_debug.r_map;
4686 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4687 prev = prev->l_next)
4688 ;
4689
4690 /* Link in the new entry. */
4691 l->l_prev = prev;
4692 l->l_next = prev->l_next;
4693 if (l->l_next != NULL)
4694 l->l_next->l_prev = l;
4695 prev->l_next = l;
4696 }
4697
4698 static void
linkmap_delete(Obj_Entry * obj)4699 linkmap_delete(Obj_Entry *obj)
4700 {
4701 struct link_map *l;
4702
4703 l = &obj->linkmap;
4704 if (l->l_prev == NULL) {
4705 if ((r_debug.r_map = l->l_next) != NULL)
4706 l->l_next->l_prev = NULL;
4707 return;
4708 }
4709
4710 if ((l->l_prev->l_next = l->l_next) != NULL)
4711 l->l_next->l_prev = l->l_prev;
4712 }
4713
4714 /*
4715 * Function for the debugger to set a breakpoint on to gain control.
4716 *
4717 * The two parameters allow the debugger to easily find and determine
4718 * what the runtime loader is doing and to whom it is doing it.
4719 *
4720 * When the loadhook trap is hit (r_debug_state, set at program
4721 * initialization), the arguments can be found on the stack:
4722 *
4723 * +8 struct link_map *m
4724 * +4 struct r_debug *rd
4725 * +0 RetAddr
4726 */
4727 void
r_debug_state(struct r_debug * rd __unused,struct link_map * m __unused)4728 r_debug_state(struct r_debug *rd __unused, struct link_map *m __unused)
4729 {
4730 /*
4731 * The following is a hack to force the compiler to emit calls to
4732 * this function, even when optimizing. If the function is empty,
4733 * the compiler is not obliged to emit any code for calls to it,
4734 * even when marked __noinline. However, gdb depends on those
4735 * calls being made.
4736 */
4737 __compiler_membar();
4738 }
4739
4740 /*
4741 * A function called after init routines have completed. This can be used to
4742 * break before a program's entry routine is called, and can be used when
4743 * main is not available in the symbol table.
4744 */
4745 void
_r_debug_postinit(struct link_map * m __unused)4746 _r_debug_postinit(struct link_map *m __unused)
4747 {
4748 /* See r_debug_state(). */
4749 __compiler_membar();
4750 }
4751
4752 static void
release_object(Obj_Entry * obj)4753 release_object(Obj_Entry *obj)
4754 {
4755 if (obj->holdcount > 0) {
4756 obj->unholdfree = true;
4757 return;
4758 }
4759 munmap(obj->mapbase, obj->mapsize);
4760 linkmap_delete(obj);
4761 obj_free(obj);
4762 }
4763
4764 /*
4765 * Get address of the pointer variable in the main program.
4766 * Prefer non-weak symbol over the weak one.
4767 */
4768 static const void **
get_program_var_addr(const char * name,RtldLockState * lockstate)4769 get_program_var_addr(const char *name, RtldLockState *lockstate)
4770 {
4771 SymLook req;
4772 DoneList donelist;
4773 const void **res;
4774
4775 symlook_init(&req, name);
4776 req.lockstate = lockstate;
4777 donelist_init(&donelist, NULL);
4778 if (symlook_global(&req, &donelist) != 0)
4779 return (NULL);
4780 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4781 res = (const void **)make_function_pointer(req.sym_out,
4782 req.defobj_out);
4783 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4784 res = (const void **)rtld_resolve_ifunc(req.defobj_out,
4785 req.sym_out);
4786 else
4787 res = (const void **)(req.defobj_out->relocbase +
4788 req.sym_out->st_value);
4789 donelist_free(&donelist);
4790 return (res);
4791 }
4792
4793 /*
4794 * Set a pointer variable in the main program to the given value. This
4795 * is used to set key variables such as "environ" before any of the
4796 * init functions are called.
4797 */
4798 static void
set_program_var(const char * name,const void * value)4799 set_program_var(const char *name, const void *value)
4800 {
4801 const void **addr;
4802
4803 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4804 dbg("\"%s\": *%p <-- %p", name, addr, value);
4805 *addr = value;
4806 }
4807 }
4808
4809 /*
4810 * Search the global objects, including dependencies and main object,
4811 * for the given symbol.
4812 */
4813 static int
symlook_global(SymLook * req,DoneList * donelist)4814 symlook_global(SymLook *req, DoneList *donelist)
4815 {
4816 SymLook req1;
4817 const Objlist_Entry *elm;
4818 int res;
4819
4820 symlook_init_from_req(&req1, req);
4821
4822 /* Search all objects loaded at program start up. */
4823 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4824 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4825 res = symlook_list(&req1, &list_main, donelist);
4826 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4827 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4828 req->sym_out = req1.sym_out;
4829 req->defobj_out = req1.defobj_out;
4830 assert(req->defobj_out != NULL);
4831 }
4832 }
4833
4834 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4835 STAILQ_FOREACH(elm, &list_global, link) {
4836 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4837 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4838 break;
4839 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4840 if (res == 0 && (req->defobj_out == NULL ||
4841 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4842 req->sym_out = req1.sym_out;
4843 req->defobj_out = req1.defobj_out;
4844 assert(req->defobj_out != NULL);
4845 }
4846 }
4847
4848 return (req->sym_out != NULL ? 0 : ESRCH);
4849 }
4850
4851 /*
4852 * Given a symbol name in a referencing object, find the corresponding
4853 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4854 * no definition was found. Returns a pointer to the Obj_Entry of the
4855 * defining object via the reference parameter DEFOBJ_OUT.
4856 */
4857 static int
symlook_default(SymLook * req,const Obj_Entry * refobj)4858 symlook_default(SymLook *req, const Obj_Entry *refobj)
4859 {
4860 DoneList donelist;
4861 const Objlist_Entry *elm;
4862 SymLook req1;
4863 int res;
4864
4865 donelist_init(&donelist, req);
4866 symlook_init_from_req(&req1, req);
4867
4868 /*
4869 * Look first in the referencing object if linked symbolically,
4870 * and similarly handle protected symbols.
4871 */
4872 res = symlook_obj(&req1, refobj);
4873 if (res == 0 && (refobj->symbolic ||
4874 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED ||
4875 refobj->deepbind)) {
4876 req->sym_out = req1.sym_out;
4877 req->defobj_out = req1.defobj_out;
4878 assert(req->defobj_out != NULL);
4879 }
4880 if (refobj->symbolic || req->defobj_out != NULL || refobj->deepbind)
4881 donelist_check(&donelist, refobj);
4882
4883 if (!refobj->deepbind)
4884 symlook_global(req, &donelist);
4885
4886 /* Search all dlopened DAGs containing the referencing object. */
4887 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4888 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4889 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4890 break;
4891 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4892 if (res == 0 && (req->sym_out == NULL ||
4893 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4894 req->sym_out = req1.sym_out;
4895 req->defobj_out = req1.defobj_out;
4896 assert(req->defobj_out != NULL);
4897 }
4898 }
4899
4900 if (refobj->deepbind)
4901 symlook_global(req, &donelist);
4902
4903 /*
4904 * Search the dynamic linker itself, and possibly resolve the
4905 * symbol from there. This is how the application links to
4906 * dynamic linker services such as dlopen.
4907 */
4908 if (req->sym_out == NULL ||
4909 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4910 res = symlook_obj(&req1, &obj_rtld);
4911 if (res == 0) {
4912 req->sym_out = req1.sym_out;
4913 req->defobj_out = req1.defobj_out;
4914 assert(req->defobj_out != NULL);
4915 }
4916 }
4917
4918 donelist_free(&donelist);
4919 return (req->sym_out != NULL ? 0 : ESRCH);
4920 }
4921
4922 static int
symlook_list(SymLook * req,const Objlist * objlist,DoneList * dlp)4923 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4924 {
4925 const Elf_Sym *def;
4926 const Obj_Entry *defobj;
4927 const Objlist_Entry *elm;
4928 SymLook req1;
4929 int res;
4930
4931 def = NULL;
4932 defobj = NULL;
4933 STAILQ_FOREACH(elm, objlist, link) {
4934 if (donelist_check(dlp, elm->obj))
4935 continue;
4936 symlook_init_from_req(&req1, req);
4937 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4938 if (def == NULL || (ld_dynamic_weak &&
4939 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4940 def = req1.sym_out;
4941 defobj = req1.defobj_out;
4942 if (!ld_dynamic_weak ||
4943 ELF_ST_BIND(def->st_info) != STB_WEAK)
4944 break;
4945 }
4946 }
4947 }
4948 if (def != NULL) {
4949 req->sym_out = def;
4950 req->defobj_out = defobj;
4951 return (0);
4952 }
4953 return (ESRCH);
4954 }
4955
4956 /*
4957 * Search the chain of DAGS cointed to by the given Needed_Entry
4958 * for a symbol of the given name. Each DAG is scanned completely
4959 * before advancing to the next one. Returns a pointer to the symbol,
4960 * or NULL if no definition was found.
4961 */
4962 static int
symlook_needed(SymLook * req,const Needed_Entry * needed,DoneList * dlp)4963 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4964 {
4965 const Elf_Sym *def;
4966 const Needed_Entry *n;
4967 const Obj_Entry *defobj;
4968 SymLook req1;
4969 int res;
4970
4971 def = NULL;
4972 defobj = NULL;
4973 symlook_init_from_req(&req1, req);
4974 for (n = needed; n != NULL; n = n->next) {
4975 if (n->obj == NULL || (res = symlook_list(&req1,
4976 &n->obj->dagmembers, dlp)) != 0)
4977 continue;
4978 if (def == NULL || (ld_dynamic_weak &&
4979 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4980 def = req1.sym_out;
4981 defobj = req1.defobj_out;
4982 if (!ld_dynamic_weak ||
4983 ELF_ST_BIND(def->st_info) != STB_WEAK)
4984 break;
4985 }
4986 }
4987 if (def != NULL) {
4988 req->sym_out = def;
4989 req->defobj_out = defobj;
4990 return (0);
4991 }
4992 return (ESRCH);
4993 }
4994
4995 static int
symlook_obj_load_filtees(SymLook * req,SymLook * req1,const Obj_Entry * obj,Needed_Entry * needed)4996 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj,
4997 Needed_Entry *needed)
4998 {
4999 DoneList donelist;
5000 int flags, res;
5001
5002 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0;
5003 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
5004 donelist_init(&donelist, NULL);
5005 symlook_init_from_req(req1, req);
5006 res = symlook_needed(req1, needed, &donelist);
5007 donelist_free(&donelist);
5008 return (res);
5009 }
5010
5011 /*
5012 * Search the symbol table of a single shared object for a symbol of
5013 * the given name and version, if requested. Returns a pointer to the
5014 * symbol, or NULL if no definition was found. If the object is
5015 * filter, return filtered symbol from filtee.
5016 *
5017 * The symbol's hash value is passed in for efficiency reasons; that
5018 * eliminates many recomputations of the hash value.
5019 */
5020 int
symlook_obj(SymLook * req,const Obj_Entry * obj)5021 symlook_obj(SymLook *req, const Obj_Entry *obj)
5022 {
5023 SymLook req1;
5024 int res, mres;
5025
5026 /*
5027 * If there is at least one valid hash at this point, we prefer to
5028 * use the faster GNU version if available.
5029 */
5030 if (obj->valid_hash_gnu)
5031 mres = symlook_obj1_gnu(req, obj);
5032 else if (obj->valid_hash_sysv)
5033 mres = symlook_obj1_sysv(req, obj);
5034 else
5035 return (EINVAL);
5036
5037 if (mres == 0) {
5038 if (obj->needed_filtees != NULL) {
5039 res = symlook_obj_load_filtees(req, &req1, obj,
5040 obj->needed_filtees);
5041 if (res == 0) {
5042 req->sym_out = req1.sym_out;
5043 req->defobj_out = req1.defobj_out;
5044 }
5045 return (res);
5046 }
5047 if (obj->needed_aux_filtees != NULL) {
5048 res = symlook_obj_load_filtees(req, &req1, obj,
5049 obj->needed_aux_filtees);
5050 if (res == 0) {
5051 req->sym_out = req1.sym_out;
5052 req->defobj_out = req1.defobj_out;
5053 return (res);
5054 }
5055 }
5056 }
5057 return (mres);
5058 }
5059
5060 /* Symbol match routine common to both hash functions */
5061 static bool
matched_symbol(SymLook * req,const Obj_Entry * obj,Sym_Match_Result * result,const unsigned long symnum)5062 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
5063 const unsigned long symnum)
5064 {
5065 Elf_Versym verndx;
5066 const Elf_Sym *symp;
5067 const char *strp;
5068
5069 symp = obj->symtab + symnum;
5070 strp = obj->strtab + symp->st_name;
5071
5072 switch (ELF_ST_TYPE(symp->st_info)) {
5073 case STT_FUNC:
5074 case STT_NOTYPE:
5075 case STT_OBJECT:
5076 case STT_COMMON:
5077 case STT_GNU_IFUNC:
5078 if (symp->st_value == 0)
5079 return (false);
5080 /* fallthrough */
5081 case STT_TLS:
5082 if (symp->st_shndx != SHN_UNDEF)
5083 break;
5084 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
5085 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
5086 break;
5087 /* fallthrough */
5088 default:
5089 return (false);
5090 }
5091 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
5092 return (false);
5093
5094 if (req->ventry == NULL) {
5095 if (obj->versyms != NULL) {
5096 verndx = VER_NDX(obj->versyms[symnum]);
5097 if (verndx > obj->vernum) {
5098 _rtld_error(
5099 "%s: symbol %s references wrong version %d",
5100 obj->path, obj->strtab + symnum, verndx);
5101 return (false);
5102 }
5103 /*
5104 * If we are not called from dlsym (i.e. this
5105 * is a normal relocation from unversioned
5106 * binary), accept the symbol immediately if
5107 * it happens to have first version after this
5108 * shared object became versioned. Otherwise,
5109 * if symbol is versioned and not hidden,
5110 * remember it. If it is the only symbol with
5111 * this name exported by the shared object, it
5112 * will be returned as a match by the calling
5113 * function. If symbol is global (verndx < 2)
5114 * accept it unconditionally.
5115 */
5116 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
5117 verndx == VER_NDX_GIVEN) {
5118 result->sym_out = symp;
5119 return (true);
5120 } else if (verndx >= VER_NDX_GIVEN) {
5121 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) ==
5122 0) {
5123 if (result->vsymp == NULL)
5124 result->vsymp = symp;
5125 result->vcount++;
5126 }
5127 return (false);
5128 }
5129 }
5130 result->sym_out = symp;
5131 return (true);
5132 }
5133 if (obj->versyms == NULL) {
5134 if (object_match_name(obj, req->ventry->name)) {
5135 _rtld_error(
5136 "%s: object %s should provide version %s for symbol %s",
5137 obj_rtld.path, obj->path, req->ventry->name,
5138 obj->strtab + symnum);
5139 return (false);
5140 }
5141 } else {
5142 verndx = VER_NDX(obj->versyms[symnum]);
5143 if (verndx > obj->vernum) {
5144 _rtld_error("%s: symbol %s references wrong version %d",
5145 obj->path, obj->strtab + symnum, verndx);
5146 return (false);
5147 }
5148 if (obj->vertab[verndx].hash != req->ventry->hash ||
5149 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
5150 /*
5151 * Version does not match. Look if this is a
5152 * global symbol and if it is not hidden. If
5153 * global symbol (verndx < 2) is available,
5154 * use it. Do not return symbol if we are
5155 * called by dlvsym, because dlvsym looks for
5156 * a specific version and default one is not
5157 * what dlvsym wants.
5158 */
5159 if ((req->flags & SYMLOOK_DLSYM) ||
5160 (verndx >= VER_NDX_GIVEN) ||
5161 (obj->versyms[symnum] & VER_NDX_HIDDEN))
5162 return (false);
5163 }
5164 }
5165 result->sym_out = symp;
5166 return (true);
5167 }
5168
5169 /*
5170 * Search for symbol using SysV hash function.
5171 * obj->buckets is known not to be NULL at this point; the test for this was
5172 * performed with the obj->valid_hash_sysv assignment.
5173 */
5174 static int
symlook_obj1_sysv(SymLook * req,const Obj_Entry * obj)5175 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
5176 {
5177 unsigned long symnum;
5178 Sym_Match_Result matchres;
5179
5180 matchres.sym_out = NULL;
5181 matchres.vsymp = NULL;
5182 matchres.vcount = 0;
5183
5184 for (symnum = obj->buckets[req->hash % obj->nbuckets];
5185 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
5186 if (symnum >= obj->nchains)
5187 return (ESRCH); /* Bad object */
5188
5189 if (matched_symbol(req, obj, &matchres, symnum)) {
5190 req->sym_out = matchres.sym_out;
5191 req->defobj_out = obj;
5192 return (0);
5193 }
5194 }
5195 if (matchres.vcount == 1) {
5196 req->sym_out = matchres.vsymp;
5197 req->defobj_out = obj;
5198 return (0);
5199 }
5200 return (ESRCH);
5201 }
5202
5203 /* Search for symbol using GNU hash function */
5204 static int
symlook_obj1_gnu(SymLook * req,const Obj_Entry * obj)5205 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
5206 {
5207 Elf_Addr bloom_word;
5208 const Elf32_Word *hashval;
5209 Elf32_Word bucket;
5210 Sym_Match_Result matchres;
5211 unsigned int h1, h2;
5212 unsigned long symnum;
5213
5214 matchres.sym_out = NULL;
5215 matchres.vsymp = NULL;
5216 matchres.vcount = 0;
5217
5218 /* Pick right bitmask word from Bloom filter array */
5219 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
5220 obj->maskwords_bm_gnu];
5221
5222 /* Calculate modulus word size of gnu hash and its derivative */
5223 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
5224 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
5225
5226 /* Filter out the "definitely not in set" queries */
5227 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
5228 return (ESRCH);
5229
5230 /* Locate hash chain and corresponding value element*/
5231 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
5232 if (bucket == 0)
5233 return (ESRCH);
5234 hashval = &obj->chain_zero_gnu[bucket];
5235 do {
5236 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
5237 symnum = hashval - obj->chain_zero_gnu;
5238 if (matched_symbol(req, obj, &matchres, symnum)) {
5239 req->sym_out = matchres.sym_out;
5240 req->defobj_out = obj;
5241 return (0);
5242 }
5243 }
5244 } while ((*hashval++ & 1) == 0);
5245 if (matchres.vcount == 1) {
5246 req->sym_out = matchres.vsymp;
5247 req->defobj_out = obj;
5248 return (0);
5249 }
5250 return (ESRCH);
5251 }
5252
5253 static void
trace_calc_fmts(const char ** main_local,const char ** fmt1,const char ** fmt2)5254 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
5255 {
5256 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
5257 if (*main_local == NULL)
5258 *main_local = "";
5259
5260 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
5261 if (*fmt1 == NULL)
5262 *fmt1 = "\t%o => %p (%x)\n";
5263
5264 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
5265 if (*fmt2 == NULL)
5266 *fmt2 = "\t%o (%x)\n";
5267 }
5268
5269 static void
trace_print_obj(Obj_Entry * obj,const char * name,const char * path,const char * main_local,const char * fmt1,const char * fmt2)5270 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
5271 const char *main_local, const char *fmt1, const char *fmt2)
5272 {
5273 const char *fmt;
5274 int c;
5275
5276 if (fmt1 == NULL)
5277 fmt = fmt2;
5278 else
5279 /* XXX bogus */
5280 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
5281
5282 while ((c = *fmt++) != '\0') {
5283 switch (c) {
5284 default:
5285 rtld_putchar(c);
5286 continue;
5287 case '\\':
5288 switch (c = *fmt) {
5289 case '\0':
5290 continue;
5291 case 'n':
5292 rtld_putchar('\n');
5293 break;
5294 case 't':
5295 rtld_putchar('\t');
5296 break;
5297 }
5298 break;
5299 case '%':
5300 switch (c = *fmt) {
5301 case '\0':
5302 continue;
5303 case '%':
5304 default:
5305 rtld_putchar(c);
5306 break;
5307 case 'A':
5308 rtld_putstr(main_local);
5309 break;
5310 case 'a':
5311 rtld_putstr(obj_main->path);
5312 break;
5313 case 'o':
5314 rtld_putstr(name);
5315 break;
5316 case 'p':
5317 rtld_putstr(path);
5318 break;
5319 case 'x':
5320 rtld_printf("%p",
5321 obj != NULL ? obj->mapbase : NULL);
5322 break;
5323 }
5324 break;
5325 }
5326 ++fmt;
5327 }
5328 }
5329
5330 static void
trace_loaded_objects(Obj_Entry * obj,bool show_preload)5331 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5332 {
5333 const char *fmt1, *fmt2, *main_local;
5334 const char *name, *path;
5335 bool first_spurious, list_containers;
5336
5337 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5338 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5339
5340 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5341 Needed_Entry *needed;
5342
5343 if (obj->marker)
5344 continue;
5345 if (list_containers && obj->needed != NULL)
5346 rtld_printf("%s:\n", obj->path);
5347 for (needed = obj->needed; needed; needed = needed->next) {
5348 if (needed->obj != NULL) {
5349 if (needed->obj->traced && !list_containers)
5350 continue;
5351 needed->obj->traced = true;
5352 path = needed->obj->path;
5353 } else
5354 path = "not found";
5355
5356 name = obj->strtab + needed->name;
5357 trace_print_obj(needed->obj, name, path, main_local,
5358 fmt1, fmt2);
5359 }
5360 }
5361
5362 if (show_preload) {
5363 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5364 fmt2 = "\t%p (%x)\n";
5365 first_spurious = true;
5366
5367 TAILQ_FOREACH(obj, &obj_list, next) {
5368 if (obj->marker || obj == obj_main || obj->traced)
5369 continue;
5370
5371 if (list_containers && first_spurious) {
5372 rtld_printf("[preloaded]\n");
5373 first_spurious = false;
5374 }
5375
5376 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5377 name = fname == NULL ? "<unknown>" : fname->name;
5378 trace_print_obj(obj, name, obj->path, main_local, NULL,
5379 fmt2);
5380 }
5381 }
5382 }
5383
5384 /*
5385 * Unload a dlopened object and its dependencies from memory and from
5386 * our data structures. It is assumed that the DAG rooted in the
5387 * object has already been unreferenced, and that the object has a
5388 * reference count of 0.
5389 */
5390 static void
unload_object(Obj_Entry * root,RtldLockState * lockstate)5391 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5392 {
5393 Obj_Entry marker, *obj, *next;
5394
5395 assert(root->refcount == 0);
5396
5397 /*
5398 * Pass over the DAG removing unreferenced objects from
5399 * appropriate lists.
5400 */
5401 unlink_object(root);
5402
5403 /* Unmap all objects that are no longer referenced. */
5404 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5405 next = TAILQ_NEXT(obj, next);
5406 if (obj->marker || obj->refcount != 0)
5407 continue;
5408 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize,
5409 0, obj->path);
5410 dbg("unloading \"%s\"", obj->path);
5411 /*
5412 * Unlink the object now to prevent new references from
5413 * being acquired while the bind lock is dropped in
5414 * recursive dlclose() invocations.
5415 */
5416 TAILQ_REMOVE(&obj_list, obj, next);
5417 obj_count--;
5418
5419 if (obj->filtees_loaded) {
5420 if (next != NULL) {
5421 init_marker(&marker);
5422 TAILQ_INSERT_BEFORE(next, &marker, next);
5423 unload_filtees(obj, lockstate);
5424 next = TAILQ_NEXT(&marker, next);
5425 TAILQ_REMOVE(&obj_list, &marker, next);
5426 } else
5427 unload_filtees(obj, lockstate);
5428 }
5429 release_object(obj);
5430 }
5431 }
5432
5433 static void
unlink_object(Obj_Entry * root)5434 unlink_object(Obj_Entry *root)
5435 {
5436 Objlist_Entry *elm;
5437
5438 if (root->refcount == 0) {
5439 /* Remove the object from the RTLD_GLOBAL list. */
5440 objlist_remove(&list_global, root);
5441
5442 /* Remove the object from all objects' DAG lists. */
5443 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5444 objlist_remove(&elm->obj->dldags, root);
5445 if (elm->obj != root)
5446 unlink_object(elm->obj);
5447 }
5448 }
5449 }
5450
5451 static void
ref_dag(Obj_Entry * root)5452 ref_dag(Obj_Entry *root)
5453 {
5454 Objlist_Entry *elm;
5455
5456 assert(root->dag_inited);
5457 STAILQ_FOREACH(elm, &root->dagmembers, link)
5458 elm->obj->refcount++;
5459 }
5460
5461 static void
unref_dag(Obj_Entry * root)5462 unref_dag(Obj_Entry *root)
5463 {
5464 Objlist_Entry *elm;
5465
5466 assert(root->dag_inited);
5467 STAILQ_FOREACH(elm, &root->dagmembers, link)
5468 elm->obj->refcount--;
5469 }
5470
5471 /*
5472 * Common code for MD __tls_get_addr().
5473 *
5474 * The tcb->tcb_dtv data structure is thread-local. The reason that
5475 * the function needs to take the rtld_bind_lock exclusive (as opposed
5476 * to only shared, to safely access obj_list in allocate_module_tls())
5477 * is to protect the rtld_malloc data.
5478 */
5479 static void *
tls_get_addr_slow(struct tcb * tcb,int index,size_t offset,bool locked)5480 tls_get_addr_slow(struct tcb *tcb, int index, size_t offset, bool locked)
5481 {
5482 struct dtv *newdtv, *dtv;
5483 RtldLockState lockstate;
5484 int to_copy;
5485
5486 dtv = tcb->tcb_dtv;
5487 /* Check dtv generation in case new modules have arrived */
5488 if (dtv->dtv_gen != tls_dtv_generation) {
5489 if (!locked)
5490 wlock_acquire(rtld_bind_lock, &lockstate);
5491 newdtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5492 sizeof(struct dtv_slot));
5493 to_copy = dtv->dtv_size;
5494 if (to_copy > tls_max_index)
5495 to_copy = tls_max_index;
5496 memcpy(newdtv->dtv_slots, dtv->dtv_slots, to_copy *
5497 sizeof(struct dtv_slot));
5498 newdtv->dtv_gen = tls_dtv_generation;
5499 newdtv->dtv_size = tls_max_index;
5500 free(dtv);
5501 if (!locked)
5502 lock_release(rtld_bind_lock, &lockstate);
5503 dtv = tcb->tcb_dtv = newdtv;
5504 }
5505
5506 /* Dynamically allocate module TLS if necessary */
5507 if (dtv->dtv_slots[index - 1].dtvs_tls == 0) {
5508 /* Signal safe, wlock will block out signals. */
5509 if (!locked)
5510 wlock_acquire(rtld_bind_lock, &lockstate);
5511 if (!dtv->dtv_slots[index - 1].dtvs_tls)
5512 dtv->dtv_slots[index - 1].dtvs_tls =
5513 allocate_module_tls(tcb, index);
5514 if (!locked)
5515 lock_release(rtld_bind_lock, &lockstate);
5516 }
5517 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5518 }
5519
5520 void *
tls_get_addr_common(struct tcb * tcb,int index,size_t offset)5521 tls_get_addr_common(struct tcb *tcb, int index, size_t offset)
5522 {
5523 struct dtv *dtv;
5524
5525 dtv = tcb->tcb_dtv;
5526 /* Check dtv generation in case new modules have arrived */
5527 if (__predict_true(dtv->dtv_gen == tls_dtv_generation &&
5528 dtv->dtv_slots[index - 1].dtvs_tls != 0))
5529 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5530 return (tls_get_addr_slow(tcb, index, offset, false));
5531 }
5532
5533 static struct tcb *
tcb_from_tcb_list_entry(struct tcb_list_entry * tcbelm)5534 tcb_from_tcb_list_entry(struct tcb_list_entry *tcbelm)
5535 {
5536 #ifdef TLS_VARIANT_I
5537 return ((struct tcb *)((char *)tcbelm - tcb_list_entry_offset));
5538 #else
5539 return ((struct tcb *)((char *)tcbelm + tcb_list_entry_offset));
5540 #endif
5541 }
5542
5543 static struct tcb_list_entry *
tcb_list_entry_from_tcb(struct tcb * tcb)5544 tcb_list_entry_from_tcb(struct tcb *tcb)
5545 {
5546 #ifdef TLS_VARIANT_I
5547 return ((struct tcb_list_entry *)((char *)tcb + tcb_list_entry_offset));
5548 #else
5549 return ((struct tcb_list_entry *)((char *)tcb - tcb_list_entry_offset));
5550 #endif
5551 }
5552
5553 static void
tcb_list_insert(struct tcb * tcb)5554 tcb_list_insert(struct tcb *tcb)
5555 {
5556 struct tcb_list_entry *tcbelm;
5557
5558 tcbelm = tcb_list_entry_from_tcb(tcb);
5559 TAILQ_INSERT_TAIL(&tcb_list, tcbelm, next);
5560 }
5561
5562 static void
tcb_list_remove(struct tcb * tcb)5563 tcb_list_remove(struct tcb *tcb)
5564 {
5565 struct tcb_list_entry *tcbelm;
5566
5567 tcbelm = tcb_list_entry_from_tcb(tcb);
5568 TAILQ_REMOVE(&tcb_list, tcbelm, next);
5569 }
5570
5571 #ifdef TLS_VARIANT_I
5572
5573 /*
5574 * Return pointer to allocated TLS block
5575 */
5576 static void *
get_tls_block_ptr(void * tcb,size_t tcbsize)5577 get_tls_block_ptr(void *tcb, size_t tcbsize)
5578 {
5579 size_t extra_size, post_size, pre_size, tls_block_size;
5580 size_t tls_init_align;
5581
5582 tls_init_align = MAX(obj_main->tlsalign, 1);
5583
5584 /* Compute fragments sizes. */
5585 extra_size = tcbsize - TLS_TCB_SIZE;
5586 post_size = calculate_tls_post_size(tls_init_align);
5587 tls_block_size = tcbsize + post_size;
5588 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5589
5590 return ((char *)tcb - pre_size - extra_size);
5591 }
5592
5593 /*
5594 * Allocate Static TLS using the Variant I method.
5595 *
5596 * For details on the layout, see lib/libc/gen/tls.c.
5597 *
5598 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5599 * it is based on tls_last_offset, and TLS offsets here are really TCB
5600 * offsets, whereas libc's tls_static_space is just the executable's static
5601 * TLS segment.
5602 *
5603 * NB: This differs from NetBSD's ld.elf_so, where TLS offsets are relative to
5604 * the end of the TCB.
5605 */
5606 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5607 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5608 {
5609 Obj_Entry *obj;
5610 char *tls_block;
5611 struct dtv *dtv;
5612 struct tcb *tcb;
5613 char *addr;
5614 size_t i;
5615 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5616 size_t tls_init_align, tls_init_offset, tls_bss_offset;
5617
5618 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5619 return (oldtcb);
5620
5621 assert(tcbsize >= TLS_TCB_SIZE);
5622 maxalign = MAX(tcbalign, tls_static_max_align);
5623 tls_init_align = MAX(obj_main->tlsalign, 1);
5624
5625 /* Compute fragments sizes. */
5626 extra_size = tcbsize - TLS_TCB_SIZE;
5627 post_size = calculate_tls_post_size(tls_init_align);
5628 tls_block_size = tcbsize + post_size;
5629 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5630 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE -
5631 post_size;
5632
5633 /* Allocate whole TLS block */
5634 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0);
5635 tcb = (struct tcb *)(tls_block + pre_size + extra_size);
5636
5637 if (oldtcb != NULL) {
5638 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5639 tls_static_space);
5640 free(get_tls_block_ptr(oldtcb, tcbsize));
5641
5642 /* Adjust the DTV. */
5643 dtv = tcb->tcb_dtv;
5644 for (i = 0; i < dtv->dtv_size; i++) {
5645 if ((uintptr_t)dtv->dtv_slots[i].dtvs_tls >=
5646 (uintptr_t)oldtcb &&
5647 (uintptr_t)dtv->dtv_slots[i].dtvs_tls <
5648 (uintptr_t)oldtcb + tls_static_space) {
5649 dtv->dtv_slots[i].dtvs_tls = (char *)tcb +
5650 (dtv->dtv_slots[i].dtvs_tls -
5651 (char *)oldtcb);
5652 }
5653 }
5654 } else {
5655 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5656 sizeof(struct dtv_slot));
5657 tcb->tcb_dtv = dtv;
5658 dtv->dtv_gen = tls_dtv_generation;
5659 dtv->dtv_size = tls_max_index;
5660
5661 for (obj = globallist_curr(objs); obj != NULL;
5662 obj = globallist_next(obj)) {
5663 if (obj->tlsoffset == 0)
5664 continue;
5665 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5666 addr = (char *)tcb + obj->tlsoffset;
5667 if (tls_init_offset > 0)
5668 memset(addr, 0, tls_init_offset);
5669 if (obj->tlsinitsize > 0) {
5670 memcpy(addr + tls_init_offset, obj->tlsinit,
5671 obj->tlsinitsize);
5672 }
5673 if (obj->tlssize > obj->tlsinitsize) {
5674 tls_bss_offset = tls_init_offset +
5675 obj->tlsinitsize;
5676 memset(addr + tls_bss_offset, 0,
5677 obj->tlssize - tls_bss_offset);
5678 }
5679 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5680 }
5681 }
5682
5683 tcb_list_insert(tcb);
5684 return (tcb);
5685 }
5686
5687 void
free_tls(void * tcb,size_t tcbsize,size_t tcbalign __unused)5688 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5689 {
5690 struct dtv *dtv;
5691 uintptr_t tlsstart, tlsend;
5692 size_t post_size;
5693 size_t i, tls_init_align __unused;
5694
5695 tcb_list_remove(tcb);
5696
5697 assert(tcbsize >= TLS_TCB_SIZE);
5698 tls_init_align = MAX(obj_main->tlsalign, 1);
5699
5700 /* Compute fragments sizes. */
5701 post_size = calculate_tls_post_size(tls_init_align);
5702
5703 tlsstart = (uintptr_t)tcb + TLS_TCB_SIZE + post_size;
5704 tlsend = (uintptr_t)tcb + tls_static_space;
5705
5706 dtv = ((struct tcb *)tcb)->tcb_dtv;
5707 for (i = 0; i < dtv->dtv_size; i++) {
5708 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5709 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5710 (uintptr_t)dtv->dtv_slots[i].dtvs_tls >= tlsend)) {
5711 free(dtv->dtv_slots[i].dtvs_tls);
5712 }
5713 }
5714 free(dtv);
5715 free(get_tls_block_ptr(tcb, tcbsize));
5716 }
5717
5718 #endif /* TLS_VARIANT_I */
5719
5720 #ifdef TLS_VARIANT_II
5721
5722 /*
5723 * Allocate Static TLS using the Variant II method.
5724 */
5725 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5726 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5727 {
5728 Obj_Entry *obj;
5729 size_t size, ralign;
5730 char *tls_block;
5731 struct dtv *dtv, *olddtv;
5732 struct tcb *tcb;
5733 char *addr;
5734 size_t i;
5735
5736 ralign = tcbalign;
5737 if (tls_static_max_align > ralign)
5738 ralign = tls_static_max_align;
5739 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5740
5741 assert(tcbsize >= 2 * sizeof(uintptr_t));
5742 tls_block = xmalloc_aligned(size, ralign, 0 /* XXX */);
5743 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5744 sizeof(struct dtv_slot));
5745
5746 tcb = (struct tcb *)(tls_block + roundup(tls_static_space, ralign));
5747 tcb->tcb_self = tcb;
5748 tcb->tcb_dtv = dtv;
5749
5750 dtv->dtv_gen = tls_dtv_generation;
5751 dtv->dtv_size = tls_max_index;
5752
5753 if (oldtcb != NULL) {
5754 /*
5755 * Copy the static TLS block over whole.
5756 */
5757 memcpy((char *)tcb - tls_static_space,
5758 (const char *)oldtcb - tls_static_space,
5759 tls_static_space);
5760
5761 /*
5762 * If any dynamic TLS blocks have been created tls_get_addr(),
5763 * move them over.
5764 */
5765 olddtv = ((struct tcb *)oldtcb)->tcb_dtv;
5766 for (i = 0; i < olddtv->dtv_size; i++) {
5767 if ((uintptr_t)olddtv->dtv_slots[i].dtvs_tls <
5768 (uintptr_t)oldtcb - size ||
5769 (uintptr_t)olddtv->dtv_slots[i].dtvs_tls >
5770 (uintptr_t)oldtcb) {
5771 dtv->dtv_slots[i].dtvs_tls =
5772 olddtv->dtv_slots[i].dtvs_tls;
5773 olddtv->dtv_slots[i].dtvs_tls = NULL;
5774 }
5775 }
5776
5777 /*
5778 * We assume that this block was the one we created with
5779 * allocate_initial_tls().
5780 */
5781 free_tls(oldtcb, 2 * sizeof(uintptr_t), sizeof(uintptr_t));
5782 } else {
5783 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5784 if (obj->marker || obj->tlsoffset == 0)
5785 continue;
5786 addr = (char *)tcb - obj->tlsoffset;
5787 memset(addr + obj->tlsinitsize, 0, obj->tlssize -
5788 obj->tlsinitsize);
5789 if (obj->tlsinit) {
5790 memcpy(addr, obj->tlsinit, obj->tlsinitsize);
5791 obj->static_tls_copied = true;
5792 }
5793 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5794 }
5795 }
5796
5797 tcb_list_insert(tcb);
5798 return (tcb);
5799 }
5800
5801 void
free_tls(void * tcb,size_t tcbsize __unused,size_t tcbalign)5802 free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
5803 {
5804 struct dtv *dtv;
5805 size_t size, ralign;
5806 size_t i;
5807 uintptr_t tlsstart, tlsend;
5808
5809 tcb_list_remove(tcb);
5810
5811 /*
5812 * Figure out the size of the initial TLS block so that we can
5813 * find stuff which ___tls_get_addr() allocated dynamically.
5814 */
5815 ralign = tcbalign;
5816 if (tls_static_max_align > ralign)
5817 ralign = tls_static_max_align;
5818 size = roundup(tls_static_space, ralign);
5819
5820 dtv = ((struct tcb *)tcb)->tcb_dtv;
5821 tlsend = (uintptr_t)tcb;
5822 tlsstart = tlsend - size;
5823 for (i = 0; i < dtv->dtv_size; i++) {
5824 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5825 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5826 (uintptr_t)dtv->dtv_slots[i].dtvs_tls > tlsend)) {
5827 free(dtv->dtv_slots[i].dtvs_tls);
5828 }
5829 }
5830
5831 free((void *)tlsstart);
5832 free(dtv);
5833 }
5834
5835 #endif /* TLS_VARIANT_II */
5836
5837 /*
5838 * Allocate TLS block for module with given index.
5839 */
5840 void *
allocate_module_tls(struct tcb * tcb,int index)5841 allocate_module_tls(struct tcb *tcb, int index)
5842 {
5843 Obj_Entry *obj;
5844 char *p;
5845
5846 TAILQ_FOREACH(obj, &obj_list, next) {
5847 if (obj->marker)
5848 continue;
5849 if (obj->tlsindex == index)
5850 break;
5851 }
5852 if (obj == NULL) {
5853 _rtld_error("Can't find module with TLS index %d", index);
5854 rtld_die();
5855 }
5856
5857 if (obj->tls_static) {
5858 #ifdef TLS_VARIANT_I
5859 p = (char *)tcb + obj->tlsoffset;
5860 #else
5861 p = (char *)tcb - obj->tlsoffset;
5862 #endif
5863 return (p);
5864 }
5865
5866 obj->tls_dynamic = true;
5867
5868 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5869 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5870 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5871 return (p);
5872 }
5873
5874 static bool
allocate_tls_offset_common(size_t * offp,size_t tlssize,size_t tlsalign,size_t tlspoffset __unused)5875 allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign,
5876 size_t tlspoffset __unused)
5877 {
5878 size_t off;
5879
5880 if (tls_last_offset == 0)
5881 off = calculate_first_tls_offset(tlssize, tlsalign,
5882 tlspoffset);
5883 else
5884 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5885 tlssize, tlsalign, tlspoffset);
5886
5887 *offp = off;
5888 #ifdef TLS_VARIANT_I
5889 off += tlssize;
5890 #endif
5891
5892 /*
5893 * If we have already fixed the size of the static TLS block, we
5894 * must stay within that size. When allocating the static TLS, we
5895 * leave a small amount of space spare to be used for dynamically
5896 * loading modules which use static TLS.
5897 */
5898 if (tls_static_space != 0) {
5899 if (off > tls_static_space)
5900 return (false);
5901 } else if (tlsalign > tls_static_max_align) {
5902 tls_static_max_align = tlsalign;
5903 }
5904
5905 tls_last_offset = off;
5906 tls_last_size = tlssize;
5907
5908 return (true);
5909 }
5910
5911 bool
allocate_tls_offset(Obj_Entry * obj)5912 allocate_tls_offset(Obj_Entry *obj)
5913 {
5914 if (obj->tls_dynamic)
5915 return (false);
5916
5917 if (obj->tls_static)
5918 return (true);
5919
5920 if (obj->tlssize == 0) {
5921 obj->tls_static = true;
5922 return (true);
5923 }
5924
5925 if (!allocate_tls_offset_common(&obj->tlsoffset, obj->tlssize,
5926 obj->tlsalign, obj->tlspoffset))
5927 return (false);
5928
5929 obj->tls_static = true;
5930
5931 return (true);
5932 }
5933
5934 void
free_tls_offset(Obj_Entry * obj)5935 free_tls_offset(Obj_Entry *obj)
5936 {
5937 /*
5938 * If we were the last thing to allocate out of the static TLS
5939 * block, we give our space back to the 'allocator'. This is a
5940 * simplistic workaround to allow libGL.so.1 to be loaded and
5941 * unloaded multiple times.
5942 */
5943 size_t off = obj->tlsoffset;
5944
5945 #ifdef TLS_VARIANT_I
5946 off += obj->tlssize;
5947 #endif
5948 if (off == tls_last_offset) {
5949 tls_last_offset -= obj->tlssize;
5950 tls_last_size = 0;
5951 }
5952 }
5953
5954 void *
_rtld_allocate_tls(void * oldtcb,size_t tcbsize,size_t tcbalign)5955 _rtld_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign)
5956 {
5957 void *ret;
5958 RtldLockState lockstate;
5959
5960 wlock_acquire(rtld_bind_lock, &lockstate);
5961 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtcb,
5962 tcbsize, tcbalign);
5963 lock_release(rtld_bind_lock, &lockstate);
5964 return (ret);
5965 }
5966
5967 void
_rtld_free_tls(void * tcb,size_t tcbsize,size_t tcbalign)5968 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5969 {
5970 RtldLockState lockstate;
5971
5972 wlock_acquire(rtld_bind_lock, &lockstate);
5973 free_tls(tcb, tcbsize, tcbalign);
5974 lock_release(rtld_bind_lock, &lockstate);
5975 }
5976
5977 static void
object_add_name(Obj_Entry * obj,const char * name)5978 object_add_name(Obj_Entry *obj, const char *name)
5979 {
5980 Name_Entry *entry;
5981 size_t len;
5982
5983 len = strlen(name);
5984 entry = malloc(sizeof(Name_Entry) + len);
5985
5986 if (entry != NULL) {
5987 strcpy(entry->name, name);
5988 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5989 }
5990 }
5991
5992 static int
object_match_name(const Obj_Entry * obj,const char * name)5993 object_match_name(const Obj_Entry *obj, const char *name)
5994 {
5995 Name_Entry *entry;
5996
5997 STAILQ_FOREACH(entry, &obj->names, link) {
5998 if (strcmp(name, entry->name) == 0)
5999 return (1);
6000 }
6001 return (0);
6002 }
6003
6004 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)6005 locate_dependency(const Obj_Entry *obj, const char *name)
6006 {
6007 const Objlist_Entry *entry;
6008 const Needed_Entry *needed;
6009
6010 STAILQ_FOREACH(entry, &list_main, link) {
6011 if (object_match_name(entry->obj, name))
6012 return (entry->obj);
6013 }
6014
6015 for (needed = obj->needed; needed != NULL; needed = needed->next) {
6016 if (strcmp(obj->strtab + needed->name, name) == 0 ||
6017 (needed->obj != NULL && object_match_name(needed->obj,
6018 name))) {
6019 /*
6020 * If there is DT_NEEDED for the name we are looking
6021 * for, we are all set. Note that object might not be
6022 * found if dependency was not loaded yet, so the
6023 * function can return NULL here. This is expected and
6024 * handled properly by the caller.
6025 */
6026 return (needed->obj);
6027 }
6028 }
6029 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
6030 obj->path, name);
6031 rtld_die();
6032 }
6033
6034 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)6035 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
6036 const Elf_Vernaux *vna)
6037 {
6038 const Elf_Verdef *vd;
6039 const char *vername;
6040
6041 vername = refobj->strtab + vna->vna_name;
6042 vd = depobj->verdef;
6043 if (vd == NULL) {
6044 _rtld_error("%s: version %s required by %s not defined",
6045 depobj->path, vername, refobj->path);
6046 return (-1);
6047 }
6048 for (;;) {
6049 if (vd->vd_version != VER_DEF_CURRENT) {
6050 _rtld_error(
6051 "%s: Unsupported version %d of Elf_Verdef entry",
6052 depobj->path, vd->vd_version);
6053 return (-1);
6054 }
6055 if (vna->vna_hash == vd->vd_hash) {
6056 const Elf_Verdaux *aux =
6057 (const Elf_Verdaux *)((const char *)vd +
6058 vd->vd_aux);
6059 if (strcmp(vername, depobj->strtab + aux->vda_name) ==
6060 0)
6061 return (0);
6062 }
6063 if (vd->vd_next == 0)
6064 break;
6065 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6066 }
6067 if (vna->vna_flags & VER_FLG_WEAK)
6068 return (0);
6069 _rtld_error("%s: version %s required by %s not found", depobj->path,
6070 vername, refobj->path);
6071 return (-1);
6072 }
6073
6074 static int
rtld_verify_object_versions(Obj_Entry * obj)6075 rtld_verify_object_versions(Obj_Entry *obj)
6076 {
6077 const Elf_Verneed *vn;
6078 const Elf_Verdef *vd;
6079 const Elf_Verdaux *vda;
6080 const Elf_Vernaux *vna;
6081 const Obj_Entry *depobj;
6082 int maxvernum, vernum;
6083
6084 if (obj->ver_checked)
6085 return (0);
6086 obj->ver_checked = true;
6087
6088 maxvernum = 0;
6089 /*
6090 * Walk over defined and required version records and figure out
6091 * max index used by any of them. Do very basic sanity checking
6092 * while there.
6093 */
6094 vn = obj->verneed;
6095 while (vn != NULL) {
6096 if (vn->vn_version != VER_NEED_CURRENT) {
6097 _rtld_error(
6098 "%s: Unsupported version %d of Elf_Verneed entry",
6099 obj->path, vn->vn_version);
6100 return (-1);
6101 }
6102 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6103 for (;;) {
6104 vernum = VER_NEED_IDX(vna->vna_other);
6105 if (vernum > maxvernum)
6106 maxvernum = vernum;
6107 if (vna->vna_next == 0)
6108 break;
6109 vna = (const Elf_Vernaux *)((const char *)vna +
6110 vna->vna_next);
6111 }
6112 if (vn->vn_next == 0)
6113 break;
6114 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6115 }
6116
6117 vd = obj->verdef;
6118 while (vd != NULL) {
6119 if (vd->vd_version != VER_DEF_CURRENT) {
6120 _rtld_error(
6121 "%s: Unsupported version %d of Elf_Verdef entry",
6122 obj->path, vd->vd_version);
6123 return (-1);
6124 }
6125 vernum = VER_DEF_IDX(vd->vd_ndx);
6126 if (vernum > maxvernum)
6127 maxvernum = vernum;
6128 if (vd->vd_next == 0)
6129 break;
6130 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6131 }
6132
6133 if (maxvernum == 0)
6134 return (0);
6135
6136 /*
6137 * Store version information in array indexable by version index.
6138 * Verify that object version requirements are satisfied along the
6139 * way.
6140 */
6141 obj->vernum = maxvernum + 1;
6142 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
6143
6144 vd = obj->verdef;
6145 while (vd != NULL) {
6146 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
6147 vernum = VER_DEF_IDX(vd->vd_ndx);
6148 assert(vernum <= maxvernum);
6149 vda = (const Elf_Verdaux *)((const char *)vd +
6150 vd->vd_aux);
6151 obj->vertab[vernum].hash = vd->vd_hash;
6152 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
6153 obj->vertab[vernum].file = NULL;
6154 obj->vertab[vernum].flags = 0;
6155 }
6156 if (vd->vd_next == 0)
6157 break;
6158 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6159 }
6160
6161 vn = obj->verneed;
6162 while (vn != NULL) {
6163 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
6164 if (depobj == NULL)
6165 return (-1);
6166 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6167 for (;;) {
6168 if (check_object_provided_version(obj, depobj, vna))
6169 return (-1);
6170 vernum = VER_NEED_IDX(vna->vna_other);
6171 assert(vernum <= maxvernum);
6172 obj->vertab[vernum].hash = vna->vna_hash;
6173 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
6174 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
6175 obj->vertab[vernum].flags = (vna->vna_other &
6176 VER_NEED_HIDDEN) != 0 ? VER_INFO_HIDDEN : 0;
6177 if (vna->vna_next == 0)
6178 break;
6179 vna = (const Elf_Vernaux *)((const char *)vna +
6180 vna->vna_next);
6181 }
6182 if (vn->vn_next == 0)
6183 break;
6184 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6185 }
6186 return (0);
6187 }
6188
6189 static int
rtld_verify_versions(const Objlist * objlist)6190 rtld_verify_versions(const Objlist *objlist)
6191 {
6192 Objlist_Entry *entry;
6193 int rc;
6194
6195 rc = 0;
6196 STAILQ_FOREACH(entry, objlist, link) {
6197 /*
6198 * Skip dummy objects or objects that have their version
6199 * requirements already checked.
6200 */
6201 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
6202 continue;
6203 if (rtld_verify_object_versions(entry->obj) == -1) {
6204 rc = -1;
6205 if (ld_tracing == NULL)
6206 break;
6207 }
6208 }
6209 if (rc == 0 || ld_tracing != NULL)
6210 rc = rtld_verify_object_versions(&obj_rtld);
6211 return (rc);
6212 }
6213
6214 const Ver_Entry *
fetch_ventry(const Obj_Entry * obj,unsigned long symnum)6215 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
6216 {
6217 Elf_Versym vernum;
6218
6219 if (obj->vertab) {
6220 vernum = VER_NDX(obj->versyms[symnum]);
6221 if (vernum >= obj->vernum) {
6222 _rtld_error("%s: symbol %s has wrong verneed value %d",
6223 obj->path, obj->strtab + symnum, vernum);
6224 } else if (obj->vertab[vernum].hash != 0) {
6225 return (&obj->vertab[vernum]);
6226 }
6227 }
6228 return (NULL);
6229 }
6230
6231 int
_rtld_get_stack_prot(void)6232 _rtld_get_stack_prot(void)
6233 {
6234 return (stack_prot);
6235 }
6236
6237 int
_rtld_is_dlopened(void * arg)6238 _rtld_is_dlopened(void *arg)
6239 {
6240 Obj_Entry *obj;
6241 RtldLockState lockstate;
6242 int res;
6243
6244 rlock_acquire(rtld_bind_lock, &lockstate);
6245 obj = dlcheck(arg);
6246 if (obj == NULL)
6247 obj = obj_from_addr(arg);
6248 if (obj == NULL) {
6249 _rtld_error("No shared object contains address");
6250 lock_release(rtld_bind_lock, &lockstate);
6251 return (-1);
6252 }
6253 res = obj->dlopened ? 1 : 0;
6254 lock_release(rtld_bind_lock, &lockstate);
6255 return (res);
6256 }
6257
6258 static int
obj_remap_relro(Obj_Entry * obj,int prot)6259 obj_remap_relro(Obj_Entry *obj, int prot)
6260 {
6261 const Elf_Phdr *ph;
6262 caddr_t relro_page;
6263 size_t relro_size;
6264
6265 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
6266 if (ph->p_type != PT_GNU_RELRO)
6267 continue;
6268 relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
6269 relro_size = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
6270 rtld_trunc_page(ph->p_vaddr);
6271 if (mprotect(relro_page, relro_size, prot) == -1) {
6272 _rtld_error(
6273 "%s: Cannot set relro protection to %#x: %s",
6274 obj->path, prot, rtld_strerror(errno));
6275 return (-1);
6276 }
6277 break;
6278 }
6279 return (0);
6280 }
6281
6282 static int
obj_disable_relro(Obj_Entry * obj)6283 obj_disable_relro(Obj_Entry *obj)
6284 {
6285 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
6286 }
6287
6288 static int
obj_enforce_relro(Obj_Entry * obj)6289 obj_enforce_relro(Obj_Entry *obj)
6290 {
6291 return (obj_remap_relro(obj, PROT_READ));
6292 }
6293
6294 static void
map_stacks_exec(RtldLockState * lockstate)6295 map_stacks_exec(RtldLockState *lockstate)
6296 {
6297 void (*thr_map_stacks_exec)(void);
6298
6299 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
6300 return;
6301 thr_map_stacks_exec = (void (*)(void))(
6302 uintptr_t)get_program_var_addr("__pthread_map_stacks_exec",
6303 lockstate);
6304 if (thr_map_stacks_exec != NULL) {
6305 stack_prot |= PROT_EXEC;
6306 thr_map_stacks_exec();
6307 }
6308 }
6309
6310 static void
distribute_static_tls(Objlist * list)6311 distribute_static_tls(Objlist *list)
6312 {
6313 struct tcb_list_entry *tcbelm;
6314 Objlist_Entry *objelm;
6315 struct tcb *tcb;
6316 Obj_Entry *obj;
6317 char *tlsbase;
6318
6319 STAILQ_FOREACH(objelm, list, link) {
6320 obj = objelm->obj;
6321 if (obj->marker || !obj->tls_static || obj->static_tls_copied)
6322 continue;
6323 TAILQ_FOREACH(tcbelm, &tcb_list, next) {
6324 tcb = tcb_from_tcb_list_entry(tcbelm);
6325 #ifdef TLS_VARIANT_I
6326 tlsbase = (char *)tcb + obj->tlsoffset;
6327 #else
6328 tlsbase = (char *)tcb - obj->tlsoffset;
6329 #endif
6330 memcpy(tlsbase, obj->tlsinit, obj->tlsinitsize);
6331 memset(tlsbase + obj->tlsinitsize, 0,
6332 obj->tlssize - obj->tlsinitsize);
6333 }
6334 obj->static_tls_copied = true;
6335 }
6336 }
6337
6338 void
symlook_init(SymLook * dst,const char * name)6339 symlook_init(SymLook *dst, const char *name)
6340 {
6341 bzero(dst, sizeof(*dst));
6342 dst->name = name;
6343 dst->hash = elf_hash(name);
6344 dst->hash_gnu = gnu_hash(name);
6345 }
6346
6347 static void
symlook_init_from_req(SymLook * dst,const SymLook * src)6348 symlook_init_from_req(SymLook *dst, const SymLook *src)
6349 {
6350 dst->name = src->name;
6351 dst->hash = src->hash;
6352 dst->hash_gnu = src->hash_gnu;
6353 dst->ventry = src->ventry;
6354 dst->flags = src->flags;
6355 dst->defobj_out = NULL;
6356 dst->sym_out = NULL;
6357 dst->lockstate = src->lockstate;
6358 dst->donelist_mem = NULL;
6359 }
6360
6361 static int
open_binary_fd(const char * argv0,bool search_in_path,const char ** binpath_res)6362 open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res)
6363 {
6364 char *binpath, *pathenv, *pe, *res1;
6365 const char *res;
6366 int fd;
6367
6368 binpath = NULL;
6369 res = NULL;
6370 if (search_in_path && strchr(argv0, '/') == NULL) {
6371 binpath = xmalloc(PATH_MAX);
6372 pathenv = getenv("PATH");
6373 if (pathenv == NULL) {
6374 _rtld_error("-p and no PATH environment variable");
6375 rtld_die();
6376 }
6377 pathenv = strdup(pathenv);
6378 if (pathenv == NULL) {
6379 _rtld_error("Cannot allocate memory");
6380 rtld_die();
6381 }
6382 fd = -1;
6383 errno = ENOENT;
6384 while ((pe = strsep(&pathenv, ":")) != NULL) {
6385 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
6386 continue;
6387 if (binpath[0] != '\0' &&
6388 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
6389 continue;
6390 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
6391 continue;
6392 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
6393 if (fd != -1 || errno != ENOENT) {
6394 res = binpath;
6395 break;
6396 }
6397 }
6398 free(pathenv);
6399 } else {
6400 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
6401 res = argv0;
6402 }
6403
6404 if (fd == -1) {
6405 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
6406 rtld_die();
6407 }
6408 if (res != NULL && res[0] != '/') {
6409 res1 = xmalloc(PATH_MAX);
6410 if (realpath(res, res1) != NULL) {
6411 if (res != argv0)
6412 free(__DECONST(char *, res));
6413 res = res1;
6414 } else {
6415 free(res1);
6416 }
6417 }
6418 *binpath_res = res;
6419 return (fd);
6420 }
6421
6422 /*
6423 * Parse a set of command-line arguments.
6424 */
6425 static int
parse_args(char * argv[],int argc,bool * use_pathp,int * fdp,const char ** argv0,bool * dir_ignore)6426 parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
6427 const char **argv0, bool *dir_ignore)
6428 {
6429 const char *arg;
6430 char machine[64];
6431 size_t sz;
6432 int arglen, fd, i, j, mib[2];
6433 char opt;
6434 bool seen_b, seen_f;
6435
6436 dbg("Parsing command-line arguments");
6437 *use_pathp = false;
6438 *fdp = -1;
6439 *dir_ignore = false;
6440 seen_b = seen_f = false;
6441
6442 for (i = 1; i < argc; i++) {
6443 arg = argv[i];
6444 dbg("argv[%d]: '%s'", i, arg);
6445
6446 /*
6447 * rtld arguments end with an explicit "--" or with the first
6448 * non-prefixed argument.
6449 */
6450 if (strcmp(arg, "--") == 0) {
6451 i++;
6452 break;
6453 }
6454 if (arg[0] != '-')
6455 break;
6456
6457 /*
6458 * All other arguments are single-character options that can
6459 * be combined, so we need to search through `arg` for them.
6460 */
6461 arglen = strlen(arg);
6462 for (j = 1; j < arglen; j++) {
6463 opt = arg[j];
6464 if (opt == 'h') {
6465 print_usage(argv[0]);
6466 _exit(0);
6467 } else if (opt == 'b') {
6468 if (seen_f) {
6469 _rtld_error("Both -b and -f specified");
6470 rtld_die();
6471 }
6472 if (j != arglen - 1) {
6473 _rtld_error("Invalid options: %s", arg);
6474 rtld_die();
6475 }
6476 i++;
6477 *argv0 = argv[i];
6478 seen_b = true;
6479 break;
6480 } else if (opt == 'd') {
6481 *dir_ignore = true;
6482 } else if (opt == 'f') {
6483 if (seen_b) {
6484 _rtld_error("Both -b and -f specified");
6485 rtld_die();
6486 }
6487
6488 /*
6489 * -f XX can be used to specify a
6490 * descriptor for the binary named at
6491 * the command line (i.e., the later
6492 * argument will specify the process
6493 * name but the descriptor is what
6494 * will actually be executed).
6495 *
6496 * -f must be the last option in the
6497 * group, e.g., -abcf <fd>.
6498 */
6499 if (j != arglen - 1) {
6500 _rtld_error("Invalid options: %s", arg);
6501 rtld_die();
6502 }
6503 i++;
6504 fd = parse_integer(argv[i]);
6505 if (fd == -1) {
6506 _rtld_error(
6507 "Invalid file descriptor: '%s'",
6508 argv[i]);
6509 rtld_die();
6510 }
6511 *fdp = fd;
6512 seen_f = true;
6513 break;
6514 } else if (opt == 'o') {
6515 struct ld_env_var_desc *l;
6516 char *n, *v;
6517 u_int ll;
6518
6519 if (j != arglen - 1) {
6520 _rtld_error("Invalid options: %s", arg);
6521 rtld_die();
6522 }
6523 i++;
6524 n = argv[i];
6525 v = strchr(n, '=');
6526 if (v == NULL) {
6527 _rtld_error("No '=' in -o parameter");
6528 rtld_die();
6529 }
6530 for (ll = 0; ll < nitems(ld_env_vars); ll++) {
6531 l = &ld_env_vars[ll];
6532 if (v - n == (ptrdiff_t)strlen(l->n) &&
6533 strncmp(n, l->n, v - n) == 0) {
6534 l->val = v + 1;
6535 break;
6536 }
6537 }
6538 if (ll == nitems(ld_env_vars)) {
6539 _rtld_error("Unknown LD_ option %s", n);
6540 rtld_die();
6541 }
6542 } else if (opt == 'p') {
6543 *use_pathp = true;
6544 } else if (opt == 'u') {
6545 u_int ll;
6546
6547 for (ll = 0; ll < nitems(ld_env_vars); ll++)
6548 ld_env_vars[ll].val = NULL;
6549 } else if (opt == 'v') {
6550 machine[0] = '\0';
6551 mib[0] = CTL_HW;
6552 mib[1] = HW_MACHINE;
6553 sz = sizeof(machine);
6554 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6555 ld_elf_hints_path = ld_get_env_var(
6556 LD_ELF_HINTS_PATH);
6557 set_ld_elf_hints_path();
6558 rtld_printf(
6559 "FreeBSD ld-elf.so.1 %s\n"
6560 "FreeBSD_version %d\n"
6561 "Default lib path %s\n"
6562 "Hints lib path %s\n"
6563 "Env prefix %s\n"
6564 "Default hint file %s\n"
6565 "Hint file %s\n"
6566 "libmap file %s\n"
6567 "Optional static TLS size %zd bytes\n",
6568 machine, __FreeBSD_version,
6569 ld_standard_library_path, gethints(false),
6570 ld_env_prefix, ld_elf_hints_default,
6571 ld_elf_hints_path, ld_path_libmap_conf,
6572 ld_static_tls_extra);
6573 _exit(0);
6574 } else {
6575 _rtld_error("Invalid argument: '%s'", arg);
6576 print_usage(argv[0]);
6577 rtld_die();
6578 }
6579 }
6580 }
6581
6582 if (!seen_b)
6583 *argv0 = argv[i];
6584 return (i);
6585 }
6586
6587 /*
6588 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6589 */
6590 static int
parse_integer(const char * str)6591 parse_integer(const char *str)
6592 {
6593 int radix;
6594 const char *orig;
6595 int n, val;
6596 char c;
6597
6598 if (str[0] == '0') {
6599 if (str[1] == 'x') {
6600 str += 2;
6601 radix = 16;
6602 } else if (str[1] == 'b') {
6603 str += 2;
6604 radix = 2;
6605 } else {
6606 str += 1;
6607 radix = 8;
6608 }
6609 } else {
6610 radix = 10;
6611 }
6612 orig = str;
6613 n = 0;
6614 for (c = *str; c != '\0'; c = *++str) {
6615 if (c >= '0' && c <= '9')
6616 val = c - '0';
6617 else if (c >= 'a' && c <= 'f')
6618 val = c - 'a' + 10;
6619 else if (c >= 'A' && c <= 'F')
6620 val = c - 'A' + 10;
6621 else
6622 return (-1);
6623 if (val >= radix)
6624 return (-1);
6625
6626 if (n > INT_MAX / radix)
6627 return (-1);
6628 n *= radix;
6629 if (n > INT_MAX - val)
6630 return (-1);
6631 n += val;
6632 }
6633
6634 /*
6635 * Make sure we actually parsed something.
6636 * Allow for lone '0'.
6637 */
6638 if (str == orig && radix != 8)
6639 return (-1);
6640 return (n);
6641 }
6642
6643 static void
print_usage(const char * argv0)6644 print_usage(const char *argv0)
6645 {
6646 rtld_printf(
6647 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6648 "\n"
6649 "Options:\n"
6650 " -h Display this help message\n"
6651 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6652 " -d Ignore lack of exec permissions for the binary\n"
6653 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6654 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n"
6655 " -p Search in PATH for named binary\n"
6656 " -u Ignore LD_ environment variables\n"
6657 " -v Display identification information\n"
6658 " -- End of RTLD options\n"
6659 " <binary> Name of process to execute\n"
6660 " <args> Arguments to the executed process\n",
6661 argv0);
6662 }
6663
6664 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6665 static const struct auxfmt {
6666 const char *name;
6667 const char *fmt;
6668 } auxfmts[] = {
6669 AUXFMT(AT_NULL, NULL),
6670 AUXFMT(AT_IGNORE, NULL),
6671 AUXFMT(AT_EXECFD, "%ld"),
6672 AUXFMT(AT_PHDR, "%p"),
6673 AUXFMT(AT_PHENT, "%lu"),
6674 AUXFMT(AT_PHNUM, "%lu"),
6675 AUXFMT(AT_PAGESZ, "%lu"),
6676 AUXFMT(AT_BASE, "%#lx"),
6677 AUXFMT(AT_FLAGS, "%#lx"),
6678 AUXFMT(AT_ENTRY, "%p"),
6679 AUXFMT(AT_NOTELF, NULL),
6680 AUXFMT(AT_UID, "%ld"),
6681 AUXFMT(AT_EUID, "%ld"),
6682 AUXFMT(AT_GID, "%ld"),
6683 AUXFMT(AT_EGID, "%ld"),
6684 AUXFMT(AT_EXECPATH, "%s"),
6685 AUXFMT(AT_CANARY, "%p"),
6686 AUXFMT(AT_CANARYLEN, "%lu"),
6687 AUXFMT(AT_OSRELDATE, "%lu"),
6688 AUXFMT(AT_NCPUS, "%lu"),
6689 AUXFMT(AT_PAGESIZES, "%p"),
6690 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6691 AUXFMT(AT_TIMEKEEP, "%p"),
6692 AUXFMT(AT_STACKPROT, "%#lx"),
6693 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6694 AUXFMT(AT_HWCAP, "%#lx"),
6695 AUXFMT(AT_HWCAP2, "%#lx"),
6696 AUXFMT(AT_BSDFLAGS, "%#lx"),
6697 AUXFMT(AT_ARGC, "%lu"),
6698 AUXFMT(AT_ARGV, "%p"),
6699 AUXFMT(AT_ENVC, "%p"),
6700 AUXFMT(AT_ENVV, "%p"),
6701 AUXFMT(AT_PS_STRINGS, "%p"),
6702 AUXFMT(AT_FXRNG, "%p"),
6703 AUXFMT(AT_KPRELOAD, "%p"),
6704 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6705 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6706 /* AT_CHERI_STATS */
6707 AUXFMT(AT_HWCAP3, "%#lx"),
6708 AUXFMT(AT_HWCAP4, "%#lx"),
6709
6710 };
6711
6712 static bool
is_ptr_fmt(const char * fmt)6713 is_ptr_fmt(const char *fmt)
6714 {
6715 char last;
6716
6717 last = fmt[strlen(fmt) - 1];
6718 return (last == 'p' || last == 's');
6719 }
6720
6721 static void
dump_auxv(Elf_Auxinfo ** aux_info)6722 dump_auxv(Elf_Auxinfo **aux_info)
6723 {
6724 Elf_Auxinfo *auxp;
6725 const struct auxfmt *fmt;
6726 int i;
6727
6728 for (i = 0; i < AT_COUNT; i++) {
6729 auxp = aux_info[i];
6730 if (auxp == NULL)
6731 continue;
6732 fmt = &auxfmts[i];
6733 if (fmt->fmt == NULL)
6734 continue;
6735 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6736 if (is_ptr_fmt(fmt->fmt)) {
6737 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6738 auxp->a_un.a_ptr);
6739 } else {
6740 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6741 auxp->a_un.a_val);
6742 }
6743 rtld_fdprintf(STDOUT_FILENO, "\n");
6744 }
6745 }
6746
6747 const char *
rtld_get_var(const char * name)6748 rtld_get_var(const char *name)
6749 {
6750 const struct ld_env_var_desc *lvd;
6751 u_int i;
6752
6753 for (i = 0; i < nitems(ld_env_vars); i++) {
6754 lvd = &ld_env_vars[i];
6755 if (strcmp(lvd->n, name) == 0)
6756 return (lvd->val);
6757 }
6758 return (NULL);
6759 }
6760
6761 static void
rtld_recalc_dangerous_ld_env(void)6762 rtld_recalc_dangerous_ld_env(void)
6763 {
6764 /*
6765 * Never reset dangerous_ld_env back to false if rtld was ever
6766 * contaminated with it set to true.
6767 */
6768 dangerous_ld_env |= libmap_disable || libmap_override != NULL ||
6769 ld_library_path != NULL || ld_preload != NULL ||
6770 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak ||
6771 ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL;
6772 }
6773
6774 static void
rtld_recalc_debug(const char * ld_debug)6775 rtld_recalc_debug(const char *ld_debug)
6776 {
6777 if (ld_debug != NULL && *ld_debug != '\0')
6778 debug = 1;
6779 }
6780
6781 static void
rtld_set_var_debug(struct ld_env_var_desc * lvd)6782 rtld_set_var_debug(struct ld_env_var_desc *lvd)
6783 {
6784 rtld_recalc_debug(lvd->val);
6785 }
6786
6787 static void
rtld_set_var_library_path(struct ld_env_var_desc * lvd)6788 rtld_set_var_library_path(struct ld_env_var_desc *lvd)
6789 {
6790 ld_library_path = lvd->val;
6791 }
6792
6793 static void
rtld_set_var_library_path_fds(struct ld_env_var_desc * lvd)6794 rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd)
6795 {
6796 ld_library_dirs = lvd->val;
6797 }
6798
6799 static void
rtld_recalc_path_rpath(const char * library_path_rpath)6800 rtld_recalc_path_rpath(const char *library_path_rpath)
6801 {
6802 if (library_path_rpath != NULL) {
6803 if (library_path_rpath[0] == 'y' ||
6804 library_path_rpath[0] == 'Y' ||
6805 library_path_rpath[0] == '1')
6806 ld_library_path_rpath = true;
6807 else
6808 ld_library_path_rpath = false;
6809 } else {
6810 ld_library_path_rpath = false;
6811 }
6812 }
6813
6814 static void
rtld_set_var_library_path_rpath(struct ld_env_var_desc * lvd)6815 rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd)
6816 {
6817 rtld_recalc_path_rpath(lvd->val);
6818 }
6819
6820 static void
rtld_recalc_bind_not(const char * bind_not_val)6821 rtld_recalc_bind_not(const char *bind_not_val)
6822 {
6823 if (ld_bind_now == NULL)
6824 ld_bind_not = bind_not_val != NULL;
6825 }
6826
6827 static void
rtld_set_var_bind_now(struct ld_env_var_desc * lvd)6828 rtld_set_var_bind_now(struct ld_env_var_desc *lvd)
6829 {
6830 ld_bind_now = lvd->val;
6831 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
6832 }
6833
6834 static void
rtld_set_var_bind_not(struct ld_env_var_desc * lvd)6835 rtld_set_var_bind_not(struct ld_env_var_desc *lvd)
6836 {
6837 rtld_recalc_bind_not(lvd->val);
6838 }
6839
6840 static void
rtld_set_var_dynamic_weak(struct ld_env_var_desc * lvd)6841 rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd)
6842 {
6843 ld_dynamic_weak = lvd->val == NULL;
6844 }
6845
6846 static void
rtld_set_var_loadfltr(struct ld_env_var_desc * lvd)6847 rtld_set_var_loadfltr(struct ld_env_var_desc *lvd)
6848 {
6849 ld_loadfltr = lvd->val != NULL;
6850 }
6851
6852 static void
rtld_set_var_libmap_disable(struct ld_env_var_desc * lvd)6853 rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd)
6854 {
6855 libmap_disable = lvd->val != NULL;
6856 }
6857
6858 int
rtld_set_var(const char * name,const char * val)6859 rtld_set_var(const char *name, const char *val)
6860 {
6861 RtldLockState lockstate;
6862 struct ld_env_var_desc *lvd;
6863 u_int i;
6864 int error;
6865
6866 error = ENOENT;
6867 wlock_acquire(rtld_bind_lock, &lockstate);
6868 for (i = 0; i < nitems(ld_env_vars); i++) {
6869 lvd = &ld_env_vars[i];
6870 if (strcmp(lvd->n, name) != 0)
6871 continue;
6872 if (!lvd->can_update || (lvd->unsecure && !trust)) {
6873 error = EPERM;
6874 break;
6875 }
6876 if (lvd->owned)
6877 free(__DECONST(char *, lvd->val));
6878 if (val != NULL)
6879 lvd->val = xstrdup(val);
6880 else
6881 lvd->val = NULL;
6882 lvd->owned = true;
6883 if (lvd->on_update != NULL)
6884 lvd->on_update(lvd);
6885 error = 0;
6886 break;
6887 }
6888 if (error == 0)
6889 rtld_recalc_dangerous_ld_env();
6890 lock_release(rtld_bind_lock, &lockstate);
6891 return (error);
6892 }
6893
6894 /*
6895 * Overrides for libc_pic-provided functions.
6896 */
6897
6898 int
__getosreldate(void)6899 __getosreldate(void)
6900 {
6901 size_t len;
6902 int oid[2];
6903 int error, osrel;
6904
6905 if (osreldate != 0)
6906 return (osreldate);
6907
6908 oid[0] = CTL_KERN;
6909 oid[1] = KERN_OSRELDATE;
6910 osrel = 0;
6911 len = sizeof(osrel);
6912 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6913 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6914 osreldate = osrel;
6915 return (osreldate);
6916 }
6917 const char *
rtld_strerror(int errnum)6918 rtld_strerror(int errnum)
6919 {
6920 if (errnum < 0 || errnum >= sys_nerr)
6921 return ("Unknown error");
6922 return (sys_errlist[errnum]);
6923 }
6924
6925 char *
getenv(const char * name)6926 getenv(const char *name)
6927 {
6928 return (__DECONST(char *, rtld_get_env_val(environ, name,
6929 strlen(name))));
6930 }
6931
6932 extern int _rtld_version__FreeBSD_version __exported;
6933 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6934
6935 extern char _rtld_version_laddr_offset __exported;
6936 char _rtld_version_laddr_offset;
6937
6938 extern char _rtld_version_dlpi_tls_data __exported;
6939 char _rtld_version_dlpi_tls_data;
6940