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