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