1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 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 <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 struct dlerror_save { 85 int seen; 86 char *msg; 87 }; 88 89 /* 90 * Function declarations. 91 */ 92 static const char *basename(const char *); 93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 94 const Elf_Dyn **, const Elf_Dyn **); 95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 96 const Elf_Dyn *); 97 static bool digest_dynamic(Obj_Entry *, int); 98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 99 static void distribute_static_tls(Objlist *, RtldLockState *); 100 static Obj_Entry *dlcheck(void *); 101 static int dlclose_locked(void *, RtldLockState *); 102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 103 int lo_flags, int mode, RtldLockState *lockstate); 104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 106 static bool donelist_check(DoneList *, const Obj_Entry *); 107 static void errmsg_restore(struct dlerror_save *); 108 static struct dlerror_save *errmsg_save(void); 109 static void *fill_search_info(const char *, size_t, void *); 110 static char *find_library(const char *, const Obj_Entry *, int *); 111 static const char *gethints(bool); 112 static void hold_object(Obj_Entry *); 113 static void unhold_object(Obj_Entry *); 114 static void init_dag(Obj_Entry *); 115 static void init_marker(Obj_Entry *); 116 static void init_pagesizes(Elf_Auxinfo **aux_info); 117 static void init_rtld(caddr_t, Elf_Auxinfo **); 118 static void initlist_add_neededs(Needed_Entry *, Objlist *); 119 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 120 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 121 static void linkmap_add(Obj_Entry *); 122 static void linkmap_delete(Obj_Entry *); 123 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 124 static void unload_filtees(Obj_Entry *, RtldLockState *); 125 static int load_needed_objects(Obj_Entry *, int); 126 static int load_preload_objects(char *, bool); 127 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 128 static void map_stacks_exec(RtldLockState *); 129 static int obj_disable_relro(Obj_Entry *); 130 static int obj_enforce_relro(Obj_Entry *); 131 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 132 static void objlist_call_init(Objlist *, RtldLockState *); 133 static void objlist_clear(Objlist *); 134 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 135 static void objlist_init(Objlist *); 136 static void objlist_push_head(Objlist *, Obj_Entry *); 137 static void objlist_push_tail(Objlist *, Obj_Entry *); 138 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 139 static void objlist_remove(Objlist *, Obj_Entry *); 140 static int open_binary_fd(const char *argv0, bool search_in_path, 141 const char **binpath_res); 142 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 143 const char **argv0); 144 static int parse_integer(const char *); 145 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 146 static void print_usage(const char *argv0); 147 static void release_object(Obj_Entry *); 148 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 149 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 150 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 151 int flags, RtldLockState *lockstate); 152 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 153 RtldLockState *); 154 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 155 static int rtld_dirname(const char *, char *); 156 static int rtld_dirname_abs(const char *, char *); 157 static void *rtld_dlopen(const char *name, int fd, int mode); 158 static void rtld_exit(void); 159 static void rtld_nop_exit(void); 160 static char *search_library_path(const char *, const char *, const char *, 161 int *); 162 static char *search_library_pathfds(const char *, const char *, int *); 163 static const void **get_program_var_addr(const char *, RtldLockState *); 164 static void set_program_var(const char *, const void *); 165 static int symlook_default(SymLook *, const Obj_Entry *refobj); 166 static int symlook_global(SymLook *, DoneList *); 167 static void symlook_init_from_req(SymLook *, const SymLook *); 168 static int symlook_list(SymLook *, const Objlist *, DoneList *); 169 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 170 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 171 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 172 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 173 static void trace_loaded_objects(Obj_Entry *); 174 static void unlink_object(Obj_Entry *); 175 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 176 static void unref_dag(Obj_Entry *); 177 static void ref_dag(Obj_Entry *); 178 static char *origin_subst_one(Obj_Entry *, char *, const char *, 179 const char *, bool); 180 static char *origin_subst(Obj_Entry *, const char *); 181 static bool obj_resolve_origin(Obj_Entry *obj); 182 static void preinit_main(void); 183 static int rtld_verify_versions(const Objlist *); 184 static int rtld_verify_object_versions(Obj_Entry *); 185 static void object_add_name(Obj_Entry *, const char *); 186 static int object_match_name(const Obj_Entry *, const char *); 187 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 188 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 189 struct dl_phdr_info *phdr_info); 190 static uint32_t gnu_hash(const char *); 191 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 192 const unsigned long); 193 194 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 195 void _r_debug_postinit(struct link_map *) __noinline __exported; 196 197 int __sys_openat(int, const char *, int, ...); 198 199 /* 200 * Data declarations. 201 */ 202 struct r_debug r_debug __exported; /* for GDB; */ 203 static bool libmap_disable; /* Disable libmap */ 204 static bool ld_loadfltr; /* Immediate filters processing */ 205 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 206 static bool trust; /* False for setuid and setgid programs */ 207 static bool dangerous_ld_env; /* True if environment variables have been 208 used to affect the libraries loaded */ 209 bool ld_bind_not; /* Disable PLT update */ 210 static char *ld_bind_now; /* Environment variable for immediate binding */ 211 static char *ld_debug; /* Environment variable for debugging */ 212 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 213 weak definition */ 214 static char *ld_library_path; /* Environment variable for search path */ 215 static char *ld_library_dirs; /* Environment variable for library descriptors */ 216 static char *ld_preload; /* Environment variable for libraries to 217 load first */ 218 static char *ld_preload_fds; /* Environment variable for libraries represented by 219 descriptors */ 220 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 221 static const char *ld_tracing; /* Called from ldd to print libs */ 222 static 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) */ 228 229 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 230 STAILQ_HEAD_INITIALIZER(list_global); 231 static Objlist list_main = /* Objects loaded at program startup */ 232 STAILQ_HEAD_INITIALIZER(list_main); 233 static Objlist list_fini = /* Objects needing fini() calls */ 234 STAILQ_HEAD_INITIALIZER(list_fini); 235 236 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 237 238 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 239 240 extern Elf_Dyn _DYNAMIC; 241 #pragma weak _DYNAMIC 242 243 int dlclose(void *) __exported; 244 char *dlerror(void) __exported; 245 void *dlopen(const char *, int) __exported; 246 void *fdlopen(int, int) __exported; 247 void *dlsym(void *, const char *) __exported; 248 dlfunc_t dlfunc(void *, const char *) __exported; 249 void *dlvsym(void *, const char *, const char *) __exported; 250 int dladdr(const void *, Dl_info *) __exported; 251 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 252 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 253 int dlinfo(void *, int , void *) __exported; 254 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 255 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 256 int _rtld_get_stack_prot(void) __exported; 257 int _rtld_is_dlopened(void *) __exported; 258 void _rtld_error(const char *, ...) __exported; 259 260 /* Only here to fix -Wmissing-prototypes warnings */ 261 int __getosreldate(void); 262 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 263 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 264 265 266 int npagesizes; 267 static int osreldate; 268 size_t *pagesizes; 269 270 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 271 static int max_stack_flags; 272 273 /* 274 * Global declarations normally provided by crt1. The dynamic linker is 275 * not built with crt1, so we have to provide them ourselves. 276 */ 277 char *__progname; 278 char **environ; 279 280 /* 281 * Used to pass argc, argv to init functions. 282 */ 283 int main_argc; 284 char **main_argv; 285 286 /* 287 * Globals to control TLS allocation. 288 */ 289 size_t tls_last_offset; /* Static TLS offset of last module */ 290 size_t tls_last_size; /* Static TLS size of last module */ 291 size_t tls_static_space; /* Static TLS space allocated */ 292 static size_t tls_static_max_align; 293 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 294 int tls_max_index = 1; /* Largest module index allocated */ 295 296 static bool ld_library_path_rpath = false; 297 bool ld_fast_sigblock = false; 298 299 /* 300 * Globals for path names, and such 301 */ 302 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 303 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 304 const char *ld_path_rtld = _PATH_RTLD; 305 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 306 const char *ld_env_prefix = LD_; 307 308 static void (*rtld_exit_ptr)(void); 309 310 /* 311 * Fill in a DoneList with an allocation large enough to hold all of 312 * the currently-loaded objects. Keep this as a macro since it calls 313 * alloca and we want that to occur within the scope of the caller. 314 */ 315 #define donelist_init(dlp) \ 316 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 317 assert((dlp)->objs != NULL), \ 318 (dlp)->num_alloc = obj_count, \ 319 (dlp)->num_used = 0) 320 321 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 322 if (ld_utrace != NULL) \ 323 ld_utrace_log(e, h, mb, ms, r, n); \ 324 } while (0) 325 326 static void 327 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 328 int refcnt, const char *name) 329 { 330 struct utrace_rtld ut; 331 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 332 333 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 334 ut.event = event; 335 ut.handle = handle; 336 ut.mapbase = mapbase; 337 ut.mapsize = mapsize; 338 ut.refcnt = refcnt; 339 bzero(ut.name, sizeof(ut.name)); 340 if (name) 341 strlcpy(ut.name, name, sizeof(ut.name)); 342 utrace(&ut, sizeof(ut)); 343 } 344 345 enum { 346 LD_BIND_NOW = 0, 347 LD_PRELOAD, 348 LD_LIBMAP, 349 LD_LIBRARY_PATH, 350 LD_LIBRARY_PATH_FDS, 351 LD_LIBMAP_DISABLE, 352 LD_BIND_NOT, 353 LD_DEBUG, 354 LD_ELF_HINTS_PATH, 355 LD_LOADFLTR, 356 LD_LIBRARY_PATH_RPATH, 357 LD_PRELOAD_FDS, 358 LD_DYNAMIC_WEAK, 359 LD_TRACE_LOADED_OBJECTS, 360 LD_UTRACE, 361 LD_DUMP_REL_PRE, 362 LD_DUMP_REL_POST, 363 LD_TRACE_LOADED_OBJECTS_PROGNAME, 364 LD_TRACE_LOADED_OBJECTS_FMT1, 365 LD_TRACE_LOADED_OBJECTS_FMT2, 366 LD_TRACE_LOADED_OBJECTS_ALL, 367 }; 368 369 struct ld_env_var_desc { 370 const char *n; 371 char *val; 372 const bool unsecure; 373 }; 374 #define LD_ENV_DESC(var, unsec) \ 375 [LD_##var] = { .n = #var, .unsecure = unsec } 376 377 static struct ld_env_var_desc ld_env_vars[] = { 378 LD_ENV_DESC(BIND_NOW, false), 379 LD_ENV_DESC(PRELOAD, true), 380 LD_ENV_DESC(LIBMAP, true), 381 LD_ENV_DESC(LIBRARY_PATH, true), 382 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 383 LD_ENV_DESC(LIBMAP_DISABLE, true), 384 LD_ENV_DESC(BIND_NOT, true), 385 LD_ENV_DESC(DEBUG, true), 386 LD_ENV_DESC(ELF_HINTS_PATH, true), 387 LD_ENV_DESC(LOADFLTR, true), 388 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 389 LD_ENV_DESC(PRELOAD_FDS, true), 390 LD_ENV_DESC(DYNAMIC_WEAK, true), 391 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 392 LD_ENV_DESC(UTRACE, false), 393 LD_ENV_DESC(DUMP_REL_PRE, false), 394 LD_ENV_DESC(DUMP_REL_POST, false), 395 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 396 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 397 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 399 }; 400 401 static char * 402 ld_get_env_var(int idx) 403 { 404 return (ld_env_vars[idx].val); 405 } 406 407 static char * 408 rtld_get_env_val(char **env, const char *name, size_t name_len) 409 { 410 char **m, *n, *v; 411 412 for (m = env; *m != NULL; m++) { 413 n = *m; 414 v = strchr(n, '='); 415 if (v == NULL) { 416 /* corrupt environment? */ 417 continue; 418 } 419 if (v - n == (ptrdiff_t)name_len && 420 strncmp(name, n, name_len) == 0) 421 return (v + 1); 422 } 423 return (NULL); 424 } 425 426 static void 427 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 428 { 429 struct ld_env_var_desc *lvd; 430 size_t prefix_len, nlen; 431 char **m, *n, *v; 432 int i; 433 434 prefix_len = strlen(env_prefix); 435 for (m = env; *m != NULL; m++) { 436 n = *m; 437 if (strncmp(env_prefix, n, prefix_len) != 0) { 438 /* Not a rtld environment variable. */ 439 continue; 440 } 441 n += prefix_len; 442 v = strchr(n, '='); 443 if (v == NULL) { 444 /* corrupt environment? */ 445 continue; 446 } 447 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 448 lvd = &ld_env_vars[i]; 449 if (lvd->val != NULL) { 450 /* Saw higher-priority variable name already. */ 451 continue; 452 } 453 nlen = strlen(lvd->n); 454 if (v - n == (ptrdiff_t)nlen && 455 strncmp(lvd->n, n, nlen) == 0) { 456 lvd->val = v + 1; 457 break; 458 } 459 } 460 } 461 } 462 463 static void 464 rtld_init_env_vars(char **env) 465 { 466 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 467 } 468 469 /* 470 * Main entry point for dynamic linking. The first argument is the 471 * stack pointer. The stack is expected to be laid out as described 472 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 473 * Specifically, the stack pointer points to a word containing 474 * ARGC. Following that in the stack is a null-terminated sequence 475 * of pointers to argument strings. Then comes a null-terminated 476 * sequence of pointers to environment strings. Finally, there is a 477 * sequence of "auxiliary vector" entries. 478 * 479 * The second argument points to a place to store the dynamic linker's 480 * exit procedure pointer and the third to a place to store the main 481 * program's object. 482 * 483 * The return value is the main program's entry point. 484 */ 485 func_ptr_type 486 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 487 { 488 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 489 Objlist_Entry *entry; 490 Obj_Entry *last_interposer, *obj, *preload_tail; 491 const Elf_Phdr *phdr; 492 Objlist initlist; 493 RtldLockState lockstate; 494 struct stat st; 495 Elf_Addr *argcp; 496 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 497 const char *argv0, *binpath; 498 struct ld_env_var_desc *lvd; 499 caddr_t imgentry; 500 char buf[MAXPATHLEN]; 501 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 502 size_t sz; 503 #ifdef __powerpc__ 504 int old_auxv_format = 1; 505 #endif 506 bool dir_enable, direct_exec, explicit_fd, search_in_path; 507 508 /* 509 * On entry, the dynamic linker itself has not been relocated yet. 510 * Be very careful not to reference any global data until after 511 * init_rtld has returned. It is OK to reference file-scope statics 512 * and string constants, and to call static and global functions. 513 */ 514 515 /* Find the auxiliary vector on the stack. */ 516 argcp = sp; 517 argc = *sp++; 518 argv = (char **) sp; 519 sp += argc + 1; /* Skip over arguments and NULL terminator */ 520 env = (char **) sp; 521 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 522 ; 523 aux = (Elf_Auxinfo *) sp; 524 525 /* Digest the auxiliary vector. */ 526 for (i = 0; i < AT_COUNT; i++) 527 aux_info[i] = NULL; 528 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 529 if (auxp->a_type < AT_COUNT) 530 aux_info[auxp->a_type] = auxp; 531 #ifdef __powerpc__ 532 if (auxp->a_type == 23) /* AT_STACKPROT */ 533 old_auxv_format = 0; 534 #endif 535 } 536 537 #ifdef __powerpc__ 538 if (old_auxv_format) { 539 /* Remap from old-style auxv numbers. */ 540 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 541 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 542 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 543 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 544 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 545 aux_info[13] = NULL; /* AT_GID */ 546 547 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 548 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 549 aux_info[16] = aux_info[14]; /* AT_CANARY */ 550 aux_info[14] = NULL; /* AT_EGID */ 551 } 552 #endif 553 554 /* Initialize and relocate ourselves. */ 555 assert(aux_info[AT_BASE] != NULL); 556 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 557 558 dlerror_dflt_init(); 559 560 __progname = obj_rtld.path; 561 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 562 environ = env; 563 main_argc = argc; 564 main_argv = argv; 565 566 if (aux_info[AT_BSDFLAGS] != NULL && 567 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 568 ld_fast_sigblock = true; 569 570 trust = !issetugid(); 571 direct_exec = false; 572 573 md_abi_variant_hook(aux_info); 574 rtld_init_env_vars(env); 575 576 fd = -1; 577 if (aux_info[AT_EXECFD] != NULL) { 578 fd = aux_info[AT_EXECFD]->a_un.a_val; 579 } else { 580 assert(aux_info[AT_PHDR] != NULL); 581 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 582 if (phdr == obj_rtld.phdr) { 583 if (!trust) { 584 _rtld_error("Tainted process refusing to run binary %s", 585 argv0); 586 rtld_die(); 587 } 588 direct_exec = true; 589 590 dbg("opening main program in direct exec mode"); 591 if (argc >= 2) { 592 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 593 explicit_fd = (fd != -1); 594 binpath = NULL; 595 if (!explicit_fd) 596 fd = open_binary_fd(argv0, search_in_path, &binpath); 597 if (fstat(fd, &st) == -1) { 598 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 599 explicit_fd ? "user-provided descriptor" : argv0, 600 rtld_strerror(errno)); 601 rtld_die(); 602 } 603 604 /* 605 * Rough emulation of the permission checks done by 606 * execve(2), only Unix DACs are checked, ACLs are 607 * ignored. Preserve the semantic of disabling owner 608 * to execute if owner x bit is cleared, even if 609 * others x bit is enabled. 610 * mmap(2) does not allow to mmap with PROT_EXEC if 611 * binary' file comes from noexec mount. We cannot 612 * set a text reference on the binary. 613 */ 614 dir_enable = false; 615 if (st.st_uid == geteuid()) { 616 if ((st.st_mode & S_IXUSR) != 0) 617 dir_enable = true; 618 } else if (st.st_gid == getegid()) { 619 if ((st.st_mode & S_IXGRP) != 0) 620 dir_enable = true; 621 } else if ((st.st_mode & S_IXOTH) != 0) { 622 dir_enable = true; 623 } 624 if (!dir_enable) { 625 _rtld_error("No execute permission for binary %s", 626 argv0); 627 rtld_die(); 628 } 629 630 /* 631 * For direct exec mode, argv[0] is the interpreter 632 * name, we must remove it and shift arguments left 633 * before invoking binary main. Since stack layout 634 * places environment pointers and aux vectors right 635 * after the terminating NULL, we must shift 636 * environment and aux as well. 637 */ 638 main_argc = argc - rtld_argc; 639 for (i = 0; i <= main_argc; i++) 640 argv[i] = argv[i + rtld_argc]; 641 *argcp -= rtld_argc; 642 environ = env = envp = argv + main_argc + 1; 643 dbg("move env from %p to %p", envp + rtld_argc, envp); 644 do { 645 *envp = *(envp + rtld_argc); 646 } while (*envp++ != NULL); 647 aux = auxp = (Elf_Auxinfo *)envp; 648 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 649 dbg("move aux from %p to %p", auxpf, aux); 650 /* XXXKIB insert place for AT_EXECPATH if not present */ 651 for (;; auxp++, auxpf++) { 652 *auxp = *auxpf; 653 if (auxp->a_type == AT_NULL) 654 break; 655 } 656 /* Since the auxiliary vector has moved, redigest it. */ 657 for (i = 0; i < AT_COUNT; i++) 658 aux_info[i] = NULL; 659 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 660 if (auxp->a_type < AT_COUNT) 661 aux_info[auxp->a_type] = auxp; 662 } 663 664 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 665 if (binpath == NULL) { 666 aux_info[AT_EXECPATH] = NULL; 667 } else { 668 if (aux_info[AT_EXECPATH] == NULL) { 669 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 670 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 671 } 672 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 673 binpath); 674 } 675 } else { 676 _rtld_error("No binary"); 677 rtld_die(); 678 } 679 } 680 } 681 682 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 683 684 /* 685 * If the process is tainted, then we un-set the dangerous environment 686 * variables. The process will be marked as tainted until setuid(2) 687 * is called. If any child process calls setuid(2) we do not want any 688 * future processes to honor the potentially un-safe variables. 689 */ 690 if (!trust) { 691 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 692 lvd = &ld_env_vars[i]; 693 if (lvd->unsecure) 694 lvd->val = NULL; 695 } 696 } 697 698 ld_debug = ld_get_env_var(LD_DEBUG); 699 if (ld_bind_now == NULL) 700 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 701 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 702 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 703 libmap_override = ld_get_env_var(LD_LIBMAP); 704 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 705 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 706 ld_preload = ld_get_env_var(LD_PRELOAD); 707 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 708 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 709 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 710 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 711 if (library_path_rpath != NULL) { 712 if (library_path_rpath[0] == 'y' || 713 library_path_rpath[0] == 'Y' || 714 library_path_rpath[0] == '1') 715 ld_library_path_rpath = true; 716 else 717 ld_library_path_rpath = false; 718 } 719 dangerous_ld_env = libmap_disable || libmap_override != NULL || 720 ld_library_path != NULL || ld_preload != NULL || 721 ld_elf_hints_path != NULL || ld_loadfltr || ld_dynamic_weak; 722 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 723 ld_utrace = ld_get_env_var(LD_UTRACE); 724 725 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 726 ld_elf_hints_path = ld_elf_hints_default; 727 728 if (ld_debug != NULL && *ld_debug != '\0') 729 debug = 1; 730 dbg("%s is initialized, base address = %p", __progname, 731 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 732 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 733 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 734 735 dbg("initializing thread locks"); 736 lockdflt_init(); 737 738 /* 739 * Load the main program, or process its program header if it is 740 * already loaded. 741 */ 742 if (fd != -1) { /* Load the main program. */ 743 dbg("loading main program"); 744 obj_main = map_object(fd, argv0, NULL); 745 close(fd); 746 if (obj_main == NULL) 747 rtld_die(); 748 max_stack_flags = obj_main->stack_flags; 749 } else { /* Main program already loaded. */ 750 dbg("processing main program's program header"); 751 assert(aux_info[AT_PHDR] != NULL); 752 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 753 assert(aux_info[AT_PHNUM] != NULL); 754 phnum = aux_info[AT_PHNUM]->a_un.a_val; 755 assert(aux_info[AT_PHENT] != NULL); 756 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 757 assert(aux_info[AT_ENTRY] != NULL); 758 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 759 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 760 rtld_die(); 761 } 762 763 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 764 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 765 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 766 if (kexecpath[0] == '/') 767 obj_main->path = kexecpath; 768 else if (getcwd(buf, sizeof(buf)) == NULL || 769 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 770 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 771 obj_main->path = xstrdup(argv0); 772 else 773 obj_main->path = xstrdup(buf); 774 } else { 775 dbg("No AT_EXECPATH or direct exec"); 776 obj_main->path = xstrdup(argv0); 777 } 778 dbg("obj_main path %s", obj_main->path); 779 obj_main->mainprog = true; 780 781 if (aux_info[AT_STACKPROT] != NULL && 782 aux_info[AT_STACKPROT]->a_un.a_val != 0) 783 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 784 785 #ifndef COMPAT_32BIT 786 /* 787 * Get the actual dynamic linker pathname from the executable if 788 * possible. (It should always be possible.) That ensures that 789 * gdb will find the right dynamic linker even if a non-standard 790 * one is being used. 791 */ 792 if (obj_main->interp != NULL && 793 strcmp(obj_main->interp, obj_rtld.path) != 0) { 794 free(obj_rtld.path); 795 obj_rtld.path = xstrdup(obj_main->interp); 796 __progname = obj_rtld.path; 797 } 798 #endif 799 800 if (!digest_dynamic(obj_main, 0)) 801 rtld_die(); 802 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 803 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 804 obj_main->dynsymcount); 805 806 linkmap_add(obj_main); 807 linkmap_add(&obj_rtld); 808 809 /* Link the main program into the list of objects. */ 810 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 811 obj_count++; 812 obj_loads++; 813 814 /* Initialize a fake symbol for resolving undefined weak references. */ 815 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 816 sym_zero.st_shndx = SHN_UNDEF; 817 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 818 819 if (!libmap_disable) 820 libmap_disable = (bool)lm_init(libmap_override); 821 822 dbg("loading LD_PRELOAD_FDS libraries"); 823 if (load_preload_objects(ld_preload_fds, true) == -1) 824 rtld_die(); 825 826 dbg("loading LD_PRELOAD libraries"); 827 if (load_preload_objects(ld_preload, false) == -1) 828 rtld_die(); 829 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 830 831 dbg("loading needed objects"); 832 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 833 0) == -1) 834 rtld_die(); 835 836 /* Make a list of all objects loaded at startup. */ 837 last_interposer = obj_main; 838 TAILQ_FOREACH(obj, &obj_list, next) { 839 if (obj->marker) 840 continue; 841 if (obj->z_interpose && obj != obj_main) { 842 objlist_put_after(&list_main, last_interposer, obj); 843 last_interposer = obj; 844 } else { 845 objlist_push_tail(&list_main, obj); 846 } 847 obj->refcount++; 848 } 849 850 dbg("checking for required versions"); 851 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 852 rtld_die(); 853 854 if (ld_tracing) { /* We're done */ 855 trace_loaded_objects(obj_main); 856 exit(0); 857 } 858 859 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 860 dump_relocations(obj_main); 861 exit (0); 862 } 863 864 /* 865 * Processing tls relocations requires having the tls offsets 866 * initialized. Prepare offsets before starting initial 867 * relocation processing. 868 */ 869 dbg("initializing initial thread local storage offsets"); 870 STAILQ_FOREACH(entry, &list_main, link) { 871 /* 872 * Allocate all the initial objects out of the static TLS 873 * block even if they didn't ask for it. 874 */ 875 allocate_tls_offset(entry->obj); 876 } 877 878 if (relocate_objects(obj_main, 879 ld_bind_now != NULL && *ld_bind_now != '\0', 880 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 881 rtld_die(); 882 883 dbg("doing copy relocations"); 884 if (do_copy_relocations(obj_main) == -1) 885 rtld_die(); 886 887 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 888 dump_relocations(obj_main); 889 exit (0); 890 } 891 892 ifunc_init(aux); 893 894 /* 895 * Setup TLS for main thread. This must be done after the 896 * relocations are processed, since tls initialization section 897 * might be the subject for relocations. 898 */ 899 dbg("initializing initial thread local storage"); 900 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 901 902 dbg("initializing key program variables"); 903 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 904 set_program_var("environ", env); 905 set_program_var("__elf_aux_vector", aux); 906 907 /* Make a list of init functions to call. */ 908 objlist_init(&initlist); 909 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 910 preload_tail, &initlist); 911 912 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 913 914 map_stacks_exec(NULL); 915 916 if (!obj_main->crt_no_init) { 917 /* 918 * Make sure we don't call the main program's init and fini 919 * functions for binaries linked with old crt1 which calls 920 * _init itself. 921 */ 922 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 923 obj_main->preinit_array = obj_main->init_array = 924 obj_main->fini_array = (Elf_Addr)NULL; 925 } 926 927 if (direct_exec) { 928 /* Set osrel for direct-execed binary */ 929 mib[0] = CTL_KERN; 930 mib[1] = KERN_PROC; 931 mib[2] = KERN_PROC_OSREL; 932 mib[3] = getpid(); 933 osrel = obj_main->osrel; 934 sz = sizeof(old_osrel); 935 dbg("setting osrel to %d", osrel); 936 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 937 } 938 939 wlock_acquire(rtld_bind_lock, &lockstate); 940 941 dbg("resolving ifuncs"); 942 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 943 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 944 rtld_die(); 945 946 rtld_exit_ptr = rtld_exit; 947 if (obj_main->crt_no_init) 948 preinit_main(); 949 objlist_call_init(&initlist, &lockstate); 950 _r_debug_postinit(&obj_main->linkmap); 951 objlist_clear(&initlist); 952 dbg("loading filtees"); 953 TAILQ_FOREACH(obj, &obj_list, next) { 954 if (obj->marker) 955 continue; 956 if (ld_loadfltr || obj->z_loadfltr) 957 load_filtees(obj, 0, &lockstate); 958 } 959 960 dbg("enforcing main obj relro"); 961 if (obj_enforce_relro(obj_main) == -1) 962 rtld_die(); 963 964 lock_release(rtld_bind_lock, &lockstate); 965 966 dbg("transferring control to program entry point = %p", obj_main->entry); 967 968 /* Return the exit procedure and the program entry point. */ 969 *exit_proc = rtld_exit_ptr; 970 *objp = obj_main; 971 return (func_ptr_type) obj_main->entry; 972 } 973 974 void * 975 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 976 { 977 void *ptr; 978 Elf_Addr target; 979 980 ptr = (void *)make_function_pointer(def, obj); 981 target = call_ifunc_resolver(ptr); 982 return ((void *)target); 983 } 984 985 /* 986 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 987 * Changes to this function should be applied there as well. 988 */ 989 Elf_Addr 990 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 991 { 992 const Elf_Rel *rel; 993 const Elf_Sym *def; 994 const Obj_Entry *defobj; 995 Elf_Addr *where; 996 Elf_Addr target; 997 RtldLockState lockstate; 998 999 rlock_acquire(rtld_bind_lock, &lockstate); 1000 if (sigsetjmp(lockstate.env, 0) != 0) 1001 lock_upgrade(rtld_bind_lock, &lockstate); 1002 if (obj->pltrel) 1003 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1004 else 1005 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1006 1007 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1008 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1009 NULL, &lockstate); 1010 if (def == NULL) 1011 rtld_die(); 1012 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1013 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1014 else 1015 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1016 1017 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1018 defobj->strtab + def->st_name, 1019 obj->path == NULL ? NULL : basename(obj->path), 1020 (void *)target, 1021 defobj->path == NULL ? NULL : basename(defobj->path)); 1022 1023 /* 1024 * Write the new contents for the jmpslot. Note that depending on 1025 * architecture, the value which we need to return back to the 1026 * lazy binding trampoline may or may not be the target 1027 * address. The value returned from reloc_jmpslot() is the value 1028 * that the trampoline needs. 1029 */ 1030 target = reloc_jmpslot(where, target, defobj, obj, rel); 1031 lock_release(rtld_bind_lock, &lockstate); 1032 return target; 1033 } 1034 1035 /* 1036 * Error reporting function. Use it like printf. If formats the message 1037 * into a buffer, and sets things up so that the next call to dlerror() 1038 * will return the message. 1039 */ 1040 void 1041 _rtld_error(const char *fmt, ...) 1042 { 1043 va_list ap; 1044 1045 va_start(ap, fmt); 1046 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1047 fmt, ap); 1048 va_end(ap); 1049 *lockinfo.dlerror_seen() = 0; 1050 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1051 } 1052 1053 /* 1054 * Return a dynamically-allocated copy of the current error message, if any. 1055 */ 1056 static struct dlerror_save * 1057 errmsg_save(void) 1058 { 1059 struct dlerror_save *res; 1060 1061 res = xmalloc(sizeof(*res)); 1062 res->seen = *lockinfo.dlerror_seen(); 1063 if (res->seen == 0) 1064 res->msg = xstrdup(lockinfo.dlerror_loc()); 1065 return (res); 1066 } 1067 1068 /* 1069 * Restore the current error message from a copy which was previously saved 1070 * by errmsg_save(). The copy is freed. 1071 */ 1072 static void 1073 errmsg_restore(struct dlerror_save *saved_msg) 1074 { 1075 if (saved_msg == NULL || saved_msg->seen == 1) { 1076 *lockinfo.dlerror_seen() = 1; 1077 } else { 1078 *lockinfo.dlerror_seen() = 0; 1079 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1080 lockinfo.dlerror_loc_sz); 1081 free(saved_msg->msg); 1082 } 1083 free(saved_msg); 1084 } 1085 1086 static const char * 1087 basename(const char *name) 1088 { 1089 const char *p = strrchr(name, '/'); 1090 return p != NULL ? p + 1 : name; 1091 } 1092 1093 static struct utsname uts; 1094 1095 static char * 1096 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1097 const char *subst, bool may_free) 1098 { 1099 char *p, *p1, *res, *resp; 1100 int subst_len, kw_len, subst_count, old_len, new_len; 1101 1102 kw_len = strlen(kw); 1103 1104 /* 1105 * First, count the number of the keyword occurrences, to 1106 * preallocate the final string. 1107 */ 1108 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1109 p1 = strstr(p, kw); 1110 if (p1 == NULL) 1111 break; 1112 } 1113 1114 /* 1115 * If the keyword is not found, just return. 1116 * 1117 * Return non-substituted string if resolution failed. We 1118 * cannot do anything more reasonable, the failure mode of the 1119 * caller is unresolved library anyway. 1120 */ 1121 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1122 return (may_free ? real : xstrdup(real)); 1123 if (obj != NULL) 1124 subst = obj->origin_path; 1125 1126 /* 1127 * There is indeed something to substitute. Calculate the 1128 * length of the resulting string, and allocate it. 1129 */ 1130 subst_len = strlen(subst); 1131 old_len = strlen(real); 1132 new_len = old_len + (subst_len - kw_len) * subst_count; 1133 res = xmalloc(new_len + 1); 1134 1135 /* 1136 * Now, execute the substitution loop. 1137 */ 1138 for (p = real, resp = res, *resp = '\0';;) { 1139 p1 = strstr(p, kw); 1140 if (p1 != NULL) { 1141 /* Copy the prefix before keyword. */ 1142 memcpy(resp, p, p1 - p); 1143 resp += p1 - p; 1144 /* Keyword replacement. */ 1145 memcpy(resp, subst, subst_len); 1146 resp += subst_len; 1147 *resp = '\0'; 1148 p = p1 + kw_len; 1149 } else 1150 break; 1151 } 1152 1153 /* Copy to the end of string and finish. */ 1154 strcat(resp, p); 1155 if (may_free) 1156 free(real); 1157 return (res); 1158 } 1159 1160 static char * 1161 origin_subst(Obj_Entry *obj, const char *real) 1162 { 1163 char *res1, *res2, *res3, *res4; 1164 1165 if (obj == NULL || !trust) 1166 return (xstrdup(real)); 1167 if (uts.sysname[0] == '\0') { 1168 if (uname(&uts) != 0) { 1169 _rtld_error("utsname failed: %d", errno); 1170 return (NULL); 1171 } 1172 } 1173 /* __DECONST is safe here since without may_free real is unchanged */ 1174 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1175 false); 1176 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1177 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1178 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1179 return (res4); 1180 } 1181 1182 void 1183 rtld_die(void) 1184 { 1185 const char *msg = dlerror(); 1186 1187 if (msg == NULL) 1188 msg = "Fatal error"; 1189 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1190 rtld_fdputstr(STDERR_FILENO, msg); 1191 rtld_fdputchar(STDERR_FILENO, '\n'); 1192 _exit(1); 1193 } 1194 1195 /* 1196 * Process a shared object's DYNAMIC section, and save the important 1197 * information in its Obj_Entry structure. 1198 */ 1199 static void 1200 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1201 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1202 { 1203 const Elf_Dyn *dynp; 1204 Needed_Entry **needed_tail = &obj->needed; 1205 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1206 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1207 const Elf_Hashelt *hashtab; 1208 const Elf32_Word *hashval; 1209 Elf32_Word bkt, nmaskwords; 1210 int bloom_size32; 1211 int plttype = DT_REL; 1212 1213 *dyn_rpath = NULL; 1214 *dyn_soname = NULL; 1215 *dyn_runpath = NULL; 1216 1217 obj->bind_now = false; 1218 dynp = obj->dynamic; 1219 if (dynp == NULL) 1220 return; 1221 for (; dynp->d_tag != DT_NULL; dynp++) { 1222 switch (dynp->d_tag) { 1223 1224 case DT_REL: 1225 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1226 break; 1227 1228 case DT_RELSZ: 1229 obj->relsize = dynp->d_un.d_val; 1230 break; 1231 1232 case DT_RELENT: 1233 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1234 break; 1235 1236 case DT_JMPREL: 1237 obj->pltrel = (const Elf_Rel *) 1238 (obj->relocbase + dynp->d_un.d_ptr); 1239 break; 1240 1241 case DT_PLTRELSZ: 1242 obj->pltrelsize = dynp->d_un.d_val; 1243 break; 1244 1245 case DT_RELA: 1246 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1247 break; 1248 1249 case DT_RELASZ: 1250 obj->relasize = dynp->d_un.d_val; 1251 break; 1252 1253 case DT_RELAENT: 1254 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1255 break; 1256 1257 case DT_PLTREL: 1258 plttype = dynp->d_un.d_val; 1259 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1260 break; 1261 1262 case DT_SYMTAB: 1263 obj->symtab = (const Elf_Sym *) 1264 (obj->relocbase + dynp->d_un.d_ptr); 1265 break; 1266 1267 case DT_SYMENT: 1268 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1269 break; 1270 1271 case DT_STRTAB: 1272 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1273 break; 1274 1275 case DT_STRSZ: 1276 obj->strsize = dynp->d_un.d_val; 1277 break; 1278 1279 case DT_VERNEED: 1280 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1281 dynp->d_un.d_val); 1282 break; 1283 1284 case DT_VERNEEDNUM: 1285 obj->verneednum = dynp->d_un.d_val; 1286 break; 1287 1288 case DT_VERDEF: 1289 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1290 dynp->d_un.d_val); 1291 break; 1292 1293 case DT_VERDEFNUM: 1294 obj->verdefnum = dynp->d_un.d_val; 1295 break; 1296 1297 case DT_VERSYM: 1298 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1299 dynp->d_un.d_val); 1300 break; 1301 1302 case DT_HASH: 1303 { 1304 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1305 dynp->d_un.d_ptr); 1306 obj->nbuckets = hashtab[0]; 1307 obj->nchains = hashtab[1]; 1308 obj->buckets = hashtab + 2; 1309 obj->chains = obj->buckets + obj->nbuckets; 1310 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1311 obj->buckets != NULL; 1312 } 1313 break; 1314 1315 case DT_GNU_HASH: 1316 { 1317 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1318 dynp->d_un.d_ptr); 1319 obj->nbuckets_gnu = hashtab[0]; 1320 obj->symndx_gnu = hashtab[1]; 1321 nmaskwords = hashtab[2]; 1322 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1323 obj->maskwords_bm_gnu = nmaskwords - 1; 1324 obj->shift2_gnu = hashtab[3]; 1325 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1326 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1327 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1328 obj->symndx_gnu; 1329 /* Number of bitmask words is required to be power of 2 */ 1330 obj->valid_hash_gnu = powerof2(nmaskwords) && 1331 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1332 } 1333 break; 1334 1335 case DT_NEEDED: 1336 if (!obj->rtld) { 1337 Needed_Entry *nep = NEW(Needed_Entry); 1338 nep->name = dynp->d_un.d_val; 1339 nep->obj = NULL; 1340 nep->next = NULL; 1341 1342 *needed_tail = nep; 1343 needed_tail = &nep->next; 1344 } 1345 break; 1346 1347 case DT_FILTER: 1348 if (!obj->rtld) { 1349 Needed_Entry *nep = NEW(Needed_Entry); 1350 nep->name = dynp->d_un.d_val; 1351 nep->obj = NULL; 1352 nep->next = NULL; 1353 1354 *needed_filtees_tail = nep; 1355 needed_filtees_tail = &nep->next; 1356 1357 if (obj->linkmap.l_refname == NULL) 1358 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1359 } 1360 break; 1361 1362 case DT_AUXILIARY: 1363 if (!obj->rtld) { 1364 Needed_Entry *nep = NEW(Needed_Entry); 1365 nep->name = dynp->d_un.d_val; 1366 nep->obj = NULL; 1367 nep->next = NULL; 1368 1369 *needed_aux_filtees_tail = nep; 1370 needed_aux_filtees_tail = &nep->next; 1371 } 1372 break; 1373 1374 case DT_PLTGOT: 1375 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1376 break; 1377 1378 case DT_TEXTREL: 1379 obj->textrel = true; 1380 break; 1381 1382 case DT_SYMBOLIC: 1383 obj->symbolic = true; 1384 break; 1385 1386 case DT_RPATH: 1387 /* 1388 * We have to wait until later to process this, because we 1389 * might not have gotten the address of the string table yet. 1390 */ 1391 *dyn_rpath = dynp; 1392 break; 1393 1394 case DT_SONAME: 1395 *dyn_soname = dynp; 1396 break; 1397 1398 case DT_RUNPATH: 1399 *dyn_runpath = dynp; 1400 break; 1401 1402 case DT_INIT: 1403 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1404 break; 1405 1406 case DT_PREINIT_ARRAY: 1407 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1408 break; 1409 1410 case DT_PREINIT_ARRAYSZ: 1411 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1412 break; 1413 1414 case DT_INIT_ARRAY: 1415 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1416 break; 1417 1418 case DT_INIT_ARRAYSZ: 1419 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1420 break; 1421 1422 case DT_FINI: 1423 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1424 break; 1425 1426 case DT_FINI_ARRAY: 1427 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1428 break; 1429 1430 case DT_FINI_ARRAYSZ: 1431 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1432 break; 1433 1434 /* 1435 * Don't process DT_DEBUG on MIPS as the dynamic section 1436 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1437 */ 1438 1439 #ifndef __mips__ 1440 case DT_DEBUG: 1441 if (!early) 1442 dbg("Filling in DT_DEBUG entry"); 1443 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1444 break; 1445 #endif 1446 1447 case DT_FLAGS: 1448 if (dynp->d_un.d_val & DF_ORIGIN) 1449 obj->z_origin = true; 1450 if (dynp->d_un.d_val & DF_SYMBOLIC) 1451 obj->symbolic = true; 1452 if (dynp->d_un.d_val & DF_TEXTREL) 1453 obj->textrel = true; 1454 if (dynp->d_un.d_val & DF_BIND_NOW) 1455 obj->bind_now = true; 1456 if (dynp->d_un.d_val & DF_STATIC_TLS) 1457 obj->static_tls = true; 1458 break; 1459 #ifdef __mips__ 1460 case DT_MIPS_LOCAL_GOTNO: 1461 obj->local_gotno = dynp->d_un.d_val; 1462 break; 1463 1464 case DT_MIPS_SYMTABNO: 1465 obj->symtabno = dynp->d_un.d_val; 1466 break; 1467 1468 case DT_MIPS_GOTSYM: 1469 obj->gotsym = dynp->d_un.d_val; 1470 break; 1471 1472 case DT_MIPS_RLD_MAP: 1473 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1474 break; 1475 1476 case DT_MIPS_RLD_MAP_REL: 1477 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1478 // section relative to the address of the tag itself. 1479 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1480 (Elf_Addr) &r_debug; 1481 break; 1482 1483 case DT_MIPS_PLTGOT: 1484 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1485 dynp->d_un.d_ptr); 1486 break; 1487 1488 #endif 1489 1490 #ifdef __powerpc__ 1491 #ifdef __powerpc64__ 1492 case DT_PPC64_GLINK: 1493 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1494 break; 1495 #else 1496 case DT_PPC_GOT: 1497 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1498 break; 1499 #endif 1500 #endif 1501 1502 case DT_FLAGS_1: 1503 if (dynp->d_un.d_val & DF_1_NOOPEN) 1504 obj->z_noopen = true; 1505 if (dynp->d_un.d_val & DF_1_ORIGIN) 1506 obj->z_origin = true; 1507 if (dynp->d_un.d_val & DF_1_GLOBAL) 1508 obj->z_global = true; 1509 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1510 obj->bind_now = true; 1511 if (dynp->d_un.d_val & DF_1_NODELETE) 1512 obj->z_nodelete = true; 1513 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1514 obj->z_loadfltr = true; 1515 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1516 obj->z_interpose = true; 1517 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1518 obj->z_nodeflib = true; 1519 if (dynp->d_un.d_val & DF_1_PIE) 1520 obj->z_pie = true; 1521 break; 1522 1523 default: 1524 if (!early) { 1525 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1526 (long)dynp->d_tag); 1527 } 1528 break; 1529 } 1530 } 1531 1532 obj->traced = false; 1533 1534 if (plttype == DT_RELA) { 1535 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1536 obj->pltrel = NULL; 1537 obj->pltrelasize = obj->pltrelsize; 1538 obj->pltrelsize = 0; 1539 } 1540 1541 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1542 if (obj->valid_hash_sysv) 1543 obj->dynsymcount = obj->nchains; 1544 else if (obj->valid_hash_gnu) { 1545 obj->dynsymcount = 0; 1546 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1547 if (obj->buckets_gnu[bkt] == 0) 1548 continue; 1549 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1550 do 1551 obj->dynsymcount++; 1552 while ((*hashval++ & 1u) == 0); 1553 } 1554 obj->dynsymcount += obj->symndx_gnu; 1555 } 1556 1557 if (obj->linkmap.l_refname != NULL) 1558 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1559 linkmap.l_refname; 1560 } 1561 1562 static bool 1563 obj_resolve_origin(Obj_Entry *obj) 1564 { 1565 1566 if (obj->origin_path != NULL) 1567 return (true); 1568 obj->origin_path = xmalloc(PATH_MAX); 1569 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1570 } 1571 1572 static bool 1573 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1574 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1575 { 1576 1577 if (obj->z_origin && !obj_resolve_origin(obj)) 1578 return (false); 1579 1580 if (dyn_runpath != NULL) { 1581 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1582 obj->runpath = origin_subst(obj, obj->runpath); 1583 } else if (dyn_rpath != NULL) { 1584 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1585 obj->rpath = origin_subst(obj, obj->rpath); 1586 } 1587 if (dyn_soname != NULL) 1588 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1589 return (true); 1590 } 1591 1592 static bool 1593 digest_dynamic(Obj_Entry *obj, int early) 1594 { 1595 const Elf_Dyn *dyn_rpath; 1596 const Elf_Dyn *dyn_soname; 1597 const Elf_Dyn *dyn_runpath; 1598 1599 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1600 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1601 } 1602 1603 /* 1604 * Process a shared object's program header. This is used only for the 1605 * main program, when the kernel has already loaded the main program 1606 * into memory before calling the dynamic linker. It creates and 1607 * returns an Obj_Entry structure. 1608 */ 1609 static Obj_Entry * 1610 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1611 { 1612 Obj_Entry *obj; 1613 const Elf_Phdr *phlimit = phdr + phnum; 1614 const Elf_Phdr *ph; 1615 Elf_Addr note_start, note_end; 1616 int nsegs = 0; 1617 1618 obj = obj_new(); 1619 for (ph = phdr; ph < phlimit; ph++) { 1620 if (ph->p_type != PT_PHDR) 1621 continue; 1622 1623 obj->phdr = phdr; 1624 obj->phsize = ph->p_memsz; 1625 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1626 break; 1627 } 1628 1629 obj->stack_flags = PF_X | PF_R | PF_W; 1630 1631 for (ph = phdr; ph < phlimit; ph++) { 1632 switch (ph->p_type) { 1633 1634 case PT_INTERP: 1635 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1636 break; 1637 1638 case PT_LOAD: 1639 if (nsegs == 0) { /* First load segment */ 1640 obj->vaddrbase = trunc_page(ph->p_vaddr); 1641 obj->mapbase = obj->vaddrbase + obj->relocbase; 1642 } else { /* Last load segment */ 1643 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1644 obj->vaddrbase; 1645 } 1646 nsegs++; 1647 break; 1648 1649 case PT_DYNAMIC: 1650 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1651 break; 1652 1653 case PT_TLS: 1654 obj->tlsindex = 1; 1655 obj->tlssize = ph->p_memsz; 1656 obj->tlsalign = ph->p_align; 1657 obj->tlsinitsize = ph->p_filesz; 1658 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1659 obj->tlspoffset = ph->p_offset; 1660 break; 1661 1662 case PT_GNU_STACK: 1663 obj->stack_flags = ph->p_flags; 1664 break; 1665 1666 case PT_GNU_RELRO: 1667 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1668 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1669 trunc_page(ph->p_vaddr); 1670 break; 1671 1672 case PT_NOTE: 1673 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1674 note_end = note_start + ph->p_filesz; 1675 digest_notes(obj, note_start, note_end); 1676 break; 1677 } 1678 } 1679 if (nsegs < 1) { 1680 _rtld_error("%s: too few PT_LOAD segments", path); 1681 return NULL; 1682 } 1683 1684 obj->entry = entry; 1685 return obj; 1686 } 1687 1688 void 1689 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1690 { 1691 const Elf_Note *note; 1692 const char *note_name; 1693 uintptr_t p; 1694 1695 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1696 note = (const Elf_Note *)((const char *)(note + 1) + 1697 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1698 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1699 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1700 note->n_descsz != sizeof(int32_t)) 1701 continue; 1702 if (note->n_type != NT_FREEBSD_ABI_TAG && 1703 note->n_type != NT_FREEBSD_FEATURE_CTL && 1704 note->n_type != NT_FREEBSD_NOINIT_TAG) 1705 continue; 1706 note_name = (const char *)(note + 1); 1707 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1708 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1709 continue; 1710 switch (note->n_type) { 1711 case NT_FREEBSD_ABI_TAG: 1712 /* FreeBSD osrel note */ 1713 p = (uintptr_t)(note + 1); 1714 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1715 obj->osrel = *(const int32_t *)(p); 1716 dbg("note osrel %d", obj->osrel); 1717 break; 1718 case NT_FREEBSD_FEATURE_CTL: 1719 /* FreeBSD ABI feature control note */ 1720 p = (uintptr_t)(note + 1); 1721 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1722 obj->fctl0 = *(const uint32_t *)(p); 1723 dbg("note fctl0 %#x", obj->fctl0); 1724 break; 1725 case NT_FREEBSD_NOINIT_TAG: 1726 /* FreeBSD 'crt does not call init' note */ 1727 obj->crt_no_init = true; 1728 dbg("note crt_no_init"); 1729 break; 1730 } 1731 } 1732 } 1733 1734 static Obj_Entry * 1735 dlcheck(void *handle) 1736 { 1737 Obj_Entry *obj; 1738 1739 TAILQ_FOREACH(obj, &obj_list, next) { 1740 if (obj == (Obj_Entry *) handle) 1741 break; 1742 } 1743 1744 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1745 _rtld_error("Invalid shared object handle %p", handle); 1746 return NULL; 1747 } 1748 return obj; 1749 } 1750 1751 /* 1752 * If the given object is already in the donelist, return true. Otherwise 1753 * add the object to the list and return false. 1754 */ 1755 static bool 1756 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1757 { 1758 unsigned int i; 1759 1760 for (i = 0; i < dlp->num_used; i++) 1761 if (dlp->objs[i] == obj) 1762 return true; 1763 /* 1764 * Our donelist allocation should always be sufficient. But if 1765 * our threads locking isn't working properly, more shared objects 1766 * could have been loaded since we allocated the list. That should 1767 * never happen, but we'll handle it properly just in case it does. 1768 */ 1769 if (dlp->num_used < dlp->num_alloc) 1770 dlp->objs[dlp->num_used++] = obj; 1771 return false; 1772 } 1773 1774 /* 1775 * Hash function for symbol table lookup. Don't even think about changing 1776 * this. It is specified by the System V ABI. 1777 */ 1778 unsigned long 1779 elf_hash(const char *name) 1780 { 1781 const unsigned char *p = (const unsigned char *) name; 1782 unsigned long h = 0; 1783 unsigned long g; 1784 1785 while (*p != '\0') { 1786 h = (h << 4) + *p++; 1787 if ((g = h & 0xf0000000) != 0) 1788 h ^= g >> 24; 1789 h &= ~g; 1790 } 1791 return h; 1792 } 1793 1794 /* 1795 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1796 * unsigned in case it's implemented with a wider type. 1797 */ 1798 static uint32_t 1799 gnu_hash(const char *s) 1800 { 1801 uint32_t h; 1802 unsigned char c; 1803 1804 h = 5381; 1805 for (c = *s; c != '\0'; c = *++s) 1806 h = h * 33 + c; 1807 return (h & 0xffffffff); 1808 } 1809 1810 1811 /* 1812 * Find the library with the given name, and return its full pathname. 1813 * The returned string is dynamically allocated. Generates an error 1814 * message and returns NULL if the library cannot be found. 1815 * 1816 * If the second argument is non-NULL, then it refers to an already- 1817 * loaded shared object, whose library search path will be searched. 1818 * 1819 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1820 * descriptor (which is close-on-exec) will be passed out via the third 1821 * argument. 1822 * 1823 * The search order is: 1824 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1825 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1826 * LD_LIBRARY_PATH 1827 * DT_RUNPATH in the referencing file 1828 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1829 * from list) 1830 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1831 * 1832 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1833 */ 1834 static char * 1835 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1836 { 1837 char *pathname, *refobj_path; 1838 const char *name; 1839 bool nodeflib, objgiven; 1840 1841 objgiven = refobj != NULL; 1842 1843 if (libmap_disable || !objgiven || 1844 (name = lm_find(refobj->path, xname)) == NULL) 1845 name = xname; 1846 1847 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1848 if (name[0] != '/' && !trust) { 1849 _rtld_error("Absolute pathname required " 1850 "for shared object \"%s\"", name); 1851 return (NULL); 1852 } 1853 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1854 __DECONST(char *, name))); 1855 } 1856 1857 dbg(" Searching for \"%s\"", name); 1858 refobj_path = objgiven ? refobj->path : NULL; 1859 1860 /* 1861 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1862 * back to pre-conforming behaviour if user requested so with 1863 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1864 * nodeflib. 1865 */ 1866 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1867 pathname = search_library_path(name, ld_library_path, 1868 refobj_path, fdp); 1869 if (pathname != NULL) 1870 return (pathname); 1871 if (refobj != NULL) { 1872 pathname = search_library_path(name, refobj->rpath, 1873 refobj_path, fdp); 1874 if (pathname != NULL) 1875 return (pathname); 1876 } 1877 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1878 if (pathname != NULL) 1879 return (pathname); 1880 pathname = search_library_path(name, gethints(false), 1881 refobj_path, fdp); 1882 if (pathname != NULL) 1883 return (pathname); 1884 pathname = search_library_path(name, ld_standard_library_path, 1885 refobj_path, fdp); 1886 if (pathname != NULL) 1887 return (pathname); 1888 } else { 1889 nodeflib = objgiven ? refobj->z_nodeflib : false; 1890 if (objgiven) { 1891 pathname = search_library_path(name, refobj->rpath, 1892 refobj->path, fdp); 1893 if (pathname != NULL) 1894 return (pathname); 1895 } 1896 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1897 pathname = search_library_path(name, obj_main->rpath, 1898 refobj_path, fdp); 1899 if (pathname != NULL) 1900 return (pathname); 1901 } 1902 pathname = search_library_path(name, ld_library_path, 1903 refobj_path, fdp); 1904 if (pathname != NULL) 1905 return (pathname); 1906 if (objgiven) { 1907 pathname = search_library_path(name, refobj->runpath, 1908 refobj_path, fdp); 1909 if (pathname != NULL) 1910 return (pathname); 1911 } 1912 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1913 if (pathname != NULL) 1914 return (pathname); 1915 pathname = search_library_path(name, gethints(nodeflib), 1916 refobj_path, fdp); 1917 if (pathname != NULL) 1918 return (pathname); 1919 if (objgiven && !nodeflib) { 1920 pathname = search_library_path(name, 1921 ld_standard_library_path, refobj_path, fdp); 1922 if (pathname != NULL) 1923 return (pathname); 1924 } 1925 } 1926 1927 if (objgiven && refobj->path != NULL) { 1928 _rtld_error("Shared object \"%s\" not found, " 1929 "required by \"%s\"", name, basename(refobj->path)); 1930 } else { 1931 _rtld_error("Shared object \"%s\" not found", name); 1932 } 1933 return (NULL); 1934 } 1935 1936 /* 1937 * Given a symbol number in a referencing object, find the corresponding 1938 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1939 * no definition was found. Returns a pointer to the Obj_Entry of the 1940 * defining object via the reference parameter DEFOBJ_OUT. 1941 */ 1942 const Elf_Sym * 1943 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1944 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1945 RtldLockState *lockstate) 1946 { 1947 const Elf_Sym *ref; 1948 const Elf_Sym *def; 1949 const Obj_Entry *defobj; 1950 const Ver_Entry *ve; 1951 SymLook req; 1952 const char *name; 1953 int res; 1954 1955 /* 1956 * If we have already found this symbol, get the information from 1957 * the cache. 1958 */ 1959 if (symnum >= refobj->dynsymcount) 1960 return NULL; /* Bad object */ 1961 if (cache != NULL && cache[symnum].sym != NULL) { 1962 *defobj_out = cache[symnum].obj; 1963 return cache[symnum].sym; 1964 } 1965 1966 ref = refobj->symtab + symnum; 1967 name = refobj->strtab + ref->st_name; 1968 def = NULL; 1969 defobj = NULL; 1970 ve = NULL; 1971 1972 /* 1973 * We don't have to do a full scale lookup if the symbol is local. 1974 * We know it will bind to the instance in this load module; to 1975 * which we already have a pointer (ie ref). By not doing a lookup, 1976 * we not only improve performance, but it also avoids unresolvable 1977 * symbols when local symbols are not in the hash table. This has 1978 * been seen with the ia64 toolchain. 1979 */ 1980 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1981 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1982 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1983 symnum); 1984 } 1985 symlook_init(&req, name); 1986 req.flags = flags; 1987 ve = req.ventry = fetch_ventry(refobj, symnum); 1988 req.lockstate = lockstate; 1989 res = symlook_default(&req, refobj); 1990 if (res == 0) { 1991 def = req.sym_out; 1992 defobj = req.defobj_out; 1993 } 1994 } else { 1995 def = ref; 1996 defobj = refobj; 1997 } 1998 1999 /* 2000 * If we found no definition and the reference is weak, treat the 2001 * symbol as having the value zero. 2002 */ 2003 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2004 def = &sym_zero; 2005 defobj = obj_main; 2006 } 2007 2008 if (def != NULL) { 2009 *defobj_out = defobj; 2010 /* Record the information in the cache to avoid subsequent lookups. */ 2011 if (cache != NULL) { 2012 cache[symnum].sym = def; 2013 cache[symnum].obj = defobj; 2014 } 2015 } else { 2016 if (refobj != &obj_rtld) 2017 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2018 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2019 } 2020 return def; 2021 } 2022 2023 /* 2024 * Return the search path from the ldconfig hints file, reading it if 2025 * necessary. If nostdlib is true, then the default search paths are 2026 * not added to result. 2027 * 2028 * Returns NULL if there are problems with the hints file, 2029 * or if the search path there is empty. 2030 */ 2031 static const char * 2032 gethints(bool nostdlib) 2033 { 2034 static char *filtered_path; 2035 static const char *hints; 2036 static struct elfhints_hdr hdr; 2037 struct fill_search_info_args sargs, hargs; 2038 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2039 struct dl_serpath *SLPpath, *hintpath; 2040 char *p; 2041 struct stat hint_stat; 2042 unsigned int SLPndx, hintndx, fndx, fcount; 2043 int fd; 2044 size_t flen; 2045 uint32_t dl; 2046 bool skip; 2047 2048 /* First call, read the hints file */ 2049 if (hints == NULL) { 2050 /* Keep from trying again in case the hints file is bad. */ 2051 hints = ""; 2052 2053 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2054 return (NULL); 2055 2056 /* 2057 * Check of hdr.dirlistlen value against type limit 2058 * intends to pacify static analyzers. Further 2059 * paranoia leads to checks that dirlist is fully 2060 * contained in the file range. 2061 */ 2062 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2063 hdr.magic != ELFHINTS_MAGIC || 2064 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2065 fstat(fd, &hint_stat) == -1) { 2066 cleanup1: 2067 close(fd); 2068 hdr.dirlistlen = 0; 2069 return (NULL); 2070 } 2071 dl = hdr.strtab; 2072 if (dl + hdr.dirlist < dl) 2073 goto cleanup1; 2074 dl += hdr.dirlist; 2075 if (dl + hdr.dirlistlen < dl) 2076 goto cleanup1; 2077 dl += hdr.dirlistlen; 2078 if (dl > hint_stat.st_size) 2079 goto cleanup1; 2080 p = xmalloc(hdr.dirlistlen + 1); 2081 if (pread(fd, p, hdr.dirlistlen + 1, 2082 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2083 p[hdr.dirlistlen] != '\0') { 2084 free(p); 2085 goto cleanup1; 2086 } 2087 hints = p; 2088 close(fd); 2089 } 2090 2091 /* 2092 * If caller agreed to receive list which includes the default 2093 * paths, we are done. Otherwise, if we still did not 2094 * calculated filtered result, do it now. 2095 */ 2096 if (!nostdlib) 2097 return (hints[0] != '\0' ? hints : NULL); 2098 if (filtered_path != NULL) 2099 goto filt_ret; 2100 2101 /* 2102 * Obtain the list of all configured search paths, and the 2103 * list of the default paths. 2104 * 2105 * First estimate the size of the results. 2106 */ 2107 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2108 smeta.dls_cnt = 0; 2109 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2110 hmeta.dls_cnt = 0; 2111 2112 sargs.request = RTLD_DI_SERINFOSIZE; 2113 sargs.serinfo = &smeta; 2114 hargs.request = RTLD_DI_SERINFOSIZE; 2115 hargs.serinfo = &hmeta; 2116 2117 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2118 &sargs); 2119 path_enumerate(hints, fill_search_info, NULL, &hargs); 2120 2121 SLPinfo = xmalloc(smeta.dls_size); 2122 hintinfo = xmalloc(hmeta.dls_size); 2123 2124 /* 2125 * Next fetch both sets of paths. 2126 */ 2127 sargs.request = RTLD_DI_SERINFO; 2128 sargs.serinfo = SLPinfo; 2129 sargs.serpath = &SLPinfo->dls_serpath[0]; 2130 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2131 2132 hargs.request = RTLD_DI_SERINFO; 2133 hargs.serinfo = hintinfo; 2134 hargs.serpath = &hintinfo->dls_serpath[0]; 2135 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2136 2137 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2138 &sargs); 2139 path_enumerate(hints, fill_search_info, NULL, &hargs); 2140 2141 /* 2142 * Now calculate the difference between two sets, by excluding 2143 * standard paths from the full set. 2144 */ 2145 fndx = 0; 2146 fcount = 0; 2147 filtered_path = xmalloc(hdr.dirlistlen + 1); 2148 hintpath = &hintinfo->dls_serpath[0]; 2149 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2150 skip = false; 2151 SLPpath = &SLPinfo->dls_serpath[0]; 2152 /* 2153 * Check each standard path against current. 2154 */ 2155 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2156 /* matched, skip the path */ 2157 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2158 skip = true; 2159 break; 2160 } 2161 } 2162 if (skip) 2163 continue; 2164 /* 2165 * Not matched against any standard path, add the path 2166 * to result. Separate consequtive paths with ':'. 2167 */ 2168 if (fcount > 0) { 2169 filtered_path[fndx] = ':'; 2170 fndx++; 2171 } 2172 fcount++; 2173 flen = strlen(hintpath->dls_name); 2174 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2175 fndx += flen; 2176 } 2177 filtered_path[fndx] = '\0'; 2178 2179 free(SLPinfo); 2180 free(hintinfo); 2181 2182 filt_ret: 2183 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2184 } 2185 2186 static void 2187 init_dag(Obj_Entry *root) 2188 { 2189 const Needed_Entry *needed; 2190 const Objlist_Entry *elm; 2191 DoneList donelist; 2192 2193 if (root->dag_inited) 2194 return; 2195 donelist_init(&donelist); 2196 2197 /* Root object belongs to own DAG. */ 2198 objlist_push_tail(&root->dldags, root); 2199 objlist_push_tail(&root->dagmembers, root); 2200 donelist_check(&donelist, root); 2201 2202 /* 2203 * Add dependencies of root object to DAG in breadth order 2204 * by exploiting the fact that each new object get added 2205 * to the tail of the dagmembers list. 2206 */ 2207 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2208 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2209 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2210 continue; 2211 objlist_push_tail(&needed->obj->dldags, root); 2212 objlist_push_tail(&root->dagmembers, needed->obj); 2213 } 2214 } 2215 root->dag_inited = true; 2216 } 2217 2218 static void 2219 init_marker(Obj_Entry *marker) 2220 { 2221 2222 bzero(marker, sizeof(*marker)); 2223 marker->marker = true; 2224 } 2225 2226 Obj_Entry * 2227 globallist_curr(const Obj_Entry *obj) 2228 { 2229 2230 for (;;) { 2231 if (obj == NULL) 2232 return (NULL); 2233 if (!obj->marker) 2234 return (__DECONST(Obj_Entry *, obj)); 2235 obj = TAILQ_PREV(obj, obj_entry_q, next); 2236 } 2237 } 2238 2239 Obj_Entry * 2240 globallist_next(const Obj_Entry *obj) 2241 { 2242 2243 for (;;) { 2244 obj = TAILQ_NEXT(obj, next); 2245 if (obj == NULL) 2246 return (NULL); 2247 if (!obj->marker) 2248 return (__DECONST(Obj_Entry *, obj)); 2249 } 2250 } 2251 2252 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2253 static void 2254 hold_object(Obj_Entry *obj) 2255 { 2256 2257 obj->holdcount++; 2258 } 2259 2260 static void 2261 unhold_object(Obj_Entry *obj) 2262 { 2263 2264 assert(obj->holdcount > 0); 2265 if (--obj->holdcount == 0 && obj->unholdfree) 2266 release_object(obj); 2267 } 2268 2269 static void 2270 process_z(Obj_Entry *root) 2271 { 2272 const Objlist_Entry *elm; 2273 Obj_Entry *obj; 2274 2275 /* 2276 * Walk over object DAG and process every dependent object 2277 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2278 * to grow their own DAG. 2279 * 2280 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2281 * symlook_global() to work. 2282 * 2283 * For DF_1_NODELETE, the DAG should have its reference upped. 2284 */ 2285 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2286 obj = elm->obj; 2287 if (obj == NULL) 2288 continue; 2289 if (obj->z_nodelete && !obj->ref_nodel) { 2290 dbg("obj %s -z nodelete", obj->path); 2291 init_dag(obj); 2292 ref_dag(obj); 2293 obj->ref_nodel = true; 2294 } 2295 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2296 dbg("obj %s -z global", obj->path); 2297 objlist_push_tail(&list_global, obj); 2298 init_dag(obj); 2299 } 2300 } 2301 } 2302 2303 static void 2304 parse_rtld_phdr(Obj_Entry *obj) 2305 { 2306 const Elf_Phdr *ph; 2307 Elf_Addr note_start, note_end; 2308 2309 obj->stack_flags = PF_X | PF_R | PF_W; 2310 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2311 obj->phsize; ph++) { 2312 switch (ph->p_type) { 2313 case PT_GNU_STACK: 2314 obj->stack_flags = ph->p_flags; 2315 break; 2316 case PT_GNU_RELRO: 2317 obj->relro_page = obj->relocbase + 2318 trunc_page(ph->p_vaddr); 2319 obj->relro_size = round_page(ph->p_memsz); 2320 break; 2321 case PT_NOTE: 2322 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2323 note_end = note_start + ph->p_filesz; 2324 digest_notes(obj, note_start, note_end); 2325 break; 2326 } 2327 } 2328 } 2329 2330 /* 2331 * Initialize the dynamic linker. The argument is the address at which 2332 * the dynamic linker has been mapped into memory. The primary task of 2333 * this function is to relocate the dynamic linker. 2334 */ 2335 static void 2336 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2337 { 2338 Obj_Entry objtmp; /* Temporary rtld object */ 2339 const Elf_Ehdr *ehdr; 2340 const Elf_Dyn *dyn_rpath; 2341 const Elf_Dyn *dyn_soname; 2342 const Elf_Dyn *dyn_runpath; 2343 2344 #ifdef RTLD_INIT_PAGESIZES_EARLY 2345 /* The page size is required by the dynamic memory allocator. */ 2346 init_pagesizes(aux_info); 2347 #endif 2348 2349 /* 2350 * Conjure up an Obj_Entry structure for the dynamic linker. 2351 * 2352 * The "path" member can't be initialized yet because string constants 2353 * cannot yet be accessed. Below we will set it correctly. 2354 */ 2355 memset(&objtmp, 0, sizeof(objtmp)); 2356 objtmp.path = NULL; 2357 objtmp.rtld = true; 2358 objtmp.mapbase = mapbase; 2359 #ifdef PIC 2360 objtmp.relocbase = mapbase; 2361 #endif 2362 2363 objtmp.dynamic = rtld_dynamic(&objtmp); 2364 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2365 assert(objtmp.needed == NULL); 2366 #if !defined(__mips__) 2367 /* MIPS has a bogus DT_TEXTREL. */ 2368 assert(!objtmp.textrel); 2369 #endif 2370 /* 2371 * Temporarily put the dynamic linker entry into the object list, so 2372 * that symbols can be found. 2373 */ 2374 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2375 2376 ehdr = (Elf_Ehdr *)mapbase; 2377 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2378 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2379 2380 /* Initialize the object list. */ 2381 TAILQ_INIT(&obj_list); 2382 2383 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2384 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2385 2386 #ifndef RTLD_INIT_PAGESIZES_EARLY 2387 /* The page size is required by the dynamic memory allocator. */ 2388 init_pagesizes(aux_info); 2389 #endif 2390 2391 if (aux_info[AT_OSRELDATE] != NULL) 2392 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2393 2394 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2395 2396 /* Replace the path with a dynamically allocated copy. */ 2397 obj_rtld.path = xstrdup(ld_path_rtld); 2398 2399 parse_rtld_phdr(&obj_rtld); 2400 if (obj_enforce_relro(&obj_rtld) == -1) 2401 rtld_die(); 2402 2403 r_debug.r_version = R_DEBUG_VERSION; 2404 r_debug.r_brk = r_debug_state; 2405 r_debug.r_state = RT_CONSISTENT; 2406 r_debug.r_ldbase = obj_rtld.relocbase; 2407 } 2408 2409 /* 2410 * Retrieve the array of supported page sizes. The kernel provides the page 2411 * sizes in increasing order. 2412 */ 2413 static void 2414 init_pagesizes(Elf_Auxinfo **aux_info) 2415 { 2416 static size_t psa[MAXPAGESIZES]; 2417 int mib[2]; 2418 size_t len, size; 2419 2420 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2421 NULL) { 2422 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2423 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2424 } else { 2425 len = 2; 2426 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2427 size = sizeof(psa); 2428 else { 2429 /* As a fallback, retrieve the base page size. */ 2430 size = sizeof(psa[0]); 2431 if (aux_info[AT_PAGESZ] != NULL) { 2432 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2433 goto psa_filled; 2434 } else { 2435 mib[0] = CTL_HW; 2436 mib[1] = HW_PAGESIZE; 2437 len = 2; 2438 } 2439 } 2440 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2441 _rtld_error("sysctl for hw.pagesize(s) failed"); 2442 rtld_die(); 2443 } 2444 psa_filled: 2445 pagesizes = psa; 2446 } 2447 npagesizes = size / sizeof(pagesizes[0]); 2448 /* Discard any invalid entries at the end of the array. */ 2449 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2450 npagesizes--; 2451 } 2452 2453 /* 2454 * Add the init functions from a needed object list (and its recursive 2455 * needed objects) to "list". This is not used directly; it is a helper 2456 * function for initlist_add_objects(). The write lock must be held 2457 * when this function is called. 2458 */ 2459 static void 2460 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2461 { 2462 /* Recursively process the successor needed objects. */ 2463 if (needed->next != NULL) 2464 initlist_add_neededs(needed->next, list); 2465 2466 /* Process the current needed object. */ 2467 if (needed->obj != NULL) 2468 initlist_add_objects(needed->obj, needed->obj, list); 2469 } 2470 2471 /* 2472 * Scan all of the DAGs rooted in the range of objects from "obj" to 2473 * "tail" and add their init functions to "list". This recurses over 2474 * the DAGs and ensure the proper init ordering such that each object's 2475 * needed libraries are initialized before the object itself. At the 2476 * same time, this function adds the objects to the global finalization 2477 * list "list_fini" in the opposite order. The write lock must be 2478 * held when this function is called. 2479 */ 2480 static void 2481 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2482 { 2483 Obj_Entry *nobj; 2484 2485 if (obj->init_scanned || obj->init_done) 2486 return; 2487 obj->init_scanned = true; 2488 2489 /* Recursively process the successor objects. */ 2490 nobj = globallist_next(obj); 2491 if (nobj != NULL && obj != tail) 2492 initlist_add_objects(nobj, tail, list); 2493 2494 /* Recursively process the needed objects. */ 2495 if (obj->needed != NULL) 2496 initlist_add_neededs(obj->needed, list); 2497 if (obj->needed_filtees != NULL) 2498 initlist_add_neededs(obj->needed_filtees, list); 2499 if (obj->needed_aux_filtees != NULL) 2500 initlist_add_neededs(obj->needed_aux_filtees, list); 2501 2502 /* Add the object to the init list. */ 2503 objlist_push_tail(list, obj); 2504 2505 /* Add the object to the global fini list in the reverse order. */ 2506 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2507 && !obj->on_fini_list) { 2508 objlist_push_head(&list_fini, obj); 2509 obj->on_fini_list = true; 2510 } 2511 } 2512 2513 #ifndef FPTR_TARGET 2514 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2515 #endif 2516 2517 static void 2518 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2519 { 2520 Needed_Entry *needed, *needed1; 2521 2522 for (needed = n; needed != NULL; needed = needed->next) { 2523 if (needed->obj != NULL) { 2524 dlclose_locked(needed->obj, lockstate); 2525 needed->obj = NULL; 2526 } 2527 } 2528 for (needed = n; needed != NULL; needed = needed1) { 2529 needed1 = needed->next; 2530 free(needed); 2531 } 2532 } 2533 2534 static void 2535 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2536 { 2537 2538 free_needed_filtees(obj->needed_filtees, lockstate); 2539 obj->needed_filtees = NULL; 2540 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2541 obj->needed_aux_filtees = NULL; 2542 obj->filtees_loaded = false; 2543 } 2544 2545 static void 2546 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2547 RtldLockState *lockstate) 2548 { 2549 2550 for (; needed != NULL; needed = needed->next) { 2551 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2552 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2553 RTLD_LOCAL, lockstate); 2554 } 2555 } 2556 2557 static void 2558 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2559 { 2560 2561 lock_restart_for_upgrade(lockstate); 2562 if (!obj->filtees_loaded) { 2563 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2564 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2565 obj->filtees_loaded = true; 2566 } 2567 } 2568 2569 static int 2570 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2571 { 2572 Obj_Entry *obj1; 2573 2574 for (; needed != NULL; needed = needed->next) { 2575 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2576 flags & ~RTLD_LO_NOLOAD); 2577 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2578 return (-1); 2579 } 2580 return (0); 2581 } 2582 2583 /* 2584 * Given a shared object, traverse its list of needed objects, and load 2585 * each of them. Returns 0 on success. Generates an error message and 2586 * returns -1 on failure. 2587 */ 2588 static int 2589 load_needed_objects(Obj_Entry *first, int flags) 2590 { 2591 Obj_Entry *obj; 2592 2593 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2594 if (obj->marker) 2595 continue; 2596 if (process_needed(obj, obj->needed, flags) == -1) 2597 return (-1); 2598 } 2599 return (0); 2600 } 2601 2602 static int 2603 load_preload_objects(char *p, bool isfd) 2604 { 2605 Obj_Entry *obj; 2606 static const char delim[] = " \t:;"; 2607 2608 if (p == NULL) 2609 return (0); 2610 2611 p += strspn(p, delim); 2612 while (*p != '\0') { 2613 const char *name; 2614 size_t len = strcspn(p, delim); 2615 char savech; 2616 int fd; 2617 2618 savech = p[len]; 2619 p[len] = '\0'; 2620 if (isfd) { 2621 name = NULL; 2622 fd = parse_integer(p); 2623 if (fd == -1) 2624 return (-1); 2625 } else { 2626 name = p; 2627 fd = -1; 2628 } 2629 2630 obj = load_object(name, fd, NULL, 0); 2631 if (obj == NULL) 2632 return (-1); /* XXX - cleanup */ 2633 obj->z_interpose = true; 2634 p[len] = savech; 2635 p += len; 2636 p += strspn(p, delim); 2637 } 2638 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2639 2640 return (0); 2641 } 2642 2643 static const char * 2644 printable_path(const char *path) 2645 { 2646 2647 return (path == NULL ? "<unknown>" : path); 2648 } 2649 2650 /* 2651 * Load a shared object into memory, if it is not already loaded. The 2652 * object may be specified by name or by user-supplied file descriptor 2653 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2654 * duplicate is. 2655 * 2656 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2657 * on failure. 2658 */ 2659 static Obj_Entry * 2660 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2661 { 2662 Obj_Entry *obj; 2663 int fd; 2664 struct stat sb; 2665 char *path; 2666 2667 fd = -1; 2668 if (name != NULL) { 2669 TAILQ_FOREACH(obj, &obj_list, next) { 2670 if (obj->marker || obj->doomed) 2671 continue; 2672 if (object_match_name(obj, name)) 2673 return (obj); 2674 } 2675 2676 path = find_library(name, refobj, &fd); 2677 if (path == NULL) 2678 return (NULL); 2679 } else 2680 path = NULL; 2681 2682 if (fd >= 0) { 2683 /* 2684 * search_library_pathfds() opens a fresh file descriptor for the 2685 * library, so there is no need to dup(). 2686 */ 2687 } else if (fd_u == -1) { 2688 /* 2689 * If we didn't find a match by pathname, or the name is not 2690 * supplied, open the file and check again by device and inode. 2691 * This avoids false mismatches caused by multiple links or ".." 2692 * in pathnames. 2693 * 2694 * To avoid a race, we open the file and use fstat() rather than 2695 * using stat(). 2696 */ 2697 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2698 _rtld_error("Cannot open \"%s\"", path); 2699 free(path); 2700 return (NULL); 2701 } 2702 } else { 2703 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2704 if (fd == -1) { 2705 _rtld_error("Cannot dup fd"); 2706 free(path); 2707 return (NULL); 2708 } 2709 } 2710 if (fstat(fd, &sb) == -1) { 2711 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2712 close(fd); 2713 free(path); 2714 return NULL; 2715 } 2716 TAILQ_FOREACH(obj, &obj_list, next) { 2717 if (obj->marker || obj->doomed) 2718 continue; 2719 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2720 break; 2721 } 2722 if (obj != NULL && name != NULL) { 2723 object_add_name(obj, name); 2724 free(path); 2725 close(fd); 2726 return obj; 2727 } 2728 if (flags & RTLD_LO_NOLOAD) { 2729 free(path); 2730 close(fd); 2731 return (NULL); 2732 } 2733 2734 /* First use of this object, so we must map it in */ 2735 obj = do_load_object(fd, name, path, &sb, flags); 2736 if (obj == NULL) 2737 free(path); 2738 close(fd); 2739 2740 return obj; 2741 } 2742 2743 static Obj_Entry * 2744 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2745 int flags) 2746 { 2747 Obj_Entry *obj; 2748 struct statfs fs; 2749 2750 /* 2751 * but first, make sure that environment variables haven't been 2752 * used to circumvent the noexec flag on a filesystem. 2753 */ 2754 if (dangerous_ld_env) { 2755 if (fstatfs(fd, &fs) != 0) { 2756 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2757 return NULL; 2758 } 2759 if (fs.f_flags & MNT_NOEXEC) { 2760 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2761 return NULL; 2762 } 2763 } 2764 dbg("loading \"%s\"", printable_path(path)); 2765 obj = map_object(fd, printable_path(path), sbp); 2766 if (obj == NULL) 2767 return NULL; 2768 2769 /* 2770 * If DT_SONAME is present in the object, digest_dynamic2 already 2771 * added it to the object names. 2772 */ 2773 if (name != NULL) 2774 object_add_name(obj, name); 2775 obj->path = path; 2776 if (!digest_dynamic(obj, 0)) 2777 goto errp; 2778 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2779 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2780 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2781 dbg("refusing to load PIE executable \"%s\"", obj->path); 2782 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2783 goto errp; 2784 } 2785 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2786 RTLD_LO_DLOPEN) { 2787 dbg("refusing to load non-loadable \"%s\"", obj->path); 2788 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2789 goto errp; 2790 } 2791 2792 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2793 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2794 obj_count++; 2795 obj_loads++; 2796 linkmap_add(obj); /* for GDB & dlinfo() */ 2797 max_stack_flags |= obj->stack_flags; 2798 2799 dbg(" %p .. %p: %s", obj->mapbase, 2800 obj->mapbase + obj->mapsize - 1, obj->path); 2801 if (obj->textrel) 2802 dbg(" WARNING: %s has impure text", obj->path); 2803 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2804 obj->path); 2805 2806 return (obj); 2807 2808 errp: 2809 munmap(obj->mapbase, obj->mapsize); 2810 obj_free(obj); 2811 return (NULL); 2812 } 2813 2814 Obj_Entry * 2815 obj_from_addr(const void *addr) 2816 { 2817 Obj_Entry *obj; 2818 2819 TAILQ_FOREACH(obj, &obj_list, next) { 2820 if (obj->marker) 2821 continue; 2822 if (addr < (void *) obj->mapbase) 2823 continue; 2824 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2825 return obj; 2826 } 2827 return NULL; 2828 } 2829 2830 static void 2831 preinit_main(void) 2832 { 2833 Elf_Addr *preinit_addr; 2834 int index; 2835 2836 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2837 if (preinit_addr == NULL) 2838 return; 2839 2840 for (index = 0; index < obj_main->preinit_array_num; index++) { 2841 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2842 dbg("calling preinit function for %s at %p", obj_main->path, 2843 (void *)preinit_addr[index]); 2844 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2845 0, 0, obj_main->path); 2846 call_init_pointer(obj_main, preinit_addr[index]); 2847 } 2848 } 2849 } 2850 2851 /* 2852 * Call the finalization functions for each of the objects in "list" 2853 * belonging to the DAG of "root" and referenced once. If NULL "root" 2854 * is specified, every finalization function will be called regardless 2855 * of the reference count and the list elements won't be freed. All of 2856 * the objects are expected to have non-NULL fini functions. 2857 */ 2858 static void 2859 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2860 { 2861 Objlist_Entry *elm; 2862 struct dlerror_save *saved_msg; 2863 Elf_Addr *fini_addr; 2864 int index; 2865 2866 assert(root == NULL || root->refcount == 1); 2867 2868 if (root != NULL) 2869 root->doomed = true; 2870 2871 /* 2872 * Preserve the current error message since a fini function might 2873 * call into the dynamic linker and overwrite it. 2874 */ 2875 saved_msg = errmsg_save(); 2876 do { 2877 STAILQ_FOREACH(elm, list, link) { 2878 if (root != NULL && (elm->obj->refcount != 1 || 2879 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2880 continue; 2881 /* Remove object from fini list to prevent recursive invocation. */ 2882 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2883 /* Ensure that new references cannot be acquired. */ 2884 elm->obj->doomed = true; 2885 2886 hold_object(elm->obj); 2887 lock_release(rtld_bind_lock, lockstate); 2888 /* 2889 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2890 * When this happens, DT_FINI_ARRAY is processed first. 2891 */ 2892 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2893 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2894 for (index = elm->obj->fini_array_num - 1; index >= 0; 2895 index--) { 2896 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2897 dbg("calling fini function for %s at %p", 2898 elm->obj->path, (void *)fini_addr[index]); 2899 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2900 (void *)fini_addr[index], 0, 0, elm->obj->path); 2901 call_initfini_pointer(elm->obj, fini_addr[index]); 2902 } 2903 } 2904 } 2905 if (elm->obj->fini != (Elf_Addr)NULL) { 2906 dbg("calling fini function for %s at %p", elm->obj->path, 2907 (void *)elm->obj->fini); 2908 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2909 0, 0, elm->obj->path); 2910 call_initfini_pointer(elm->obj, elm->obj->fini); 2911 } 2912 wlock_acquire(rtld_bind_lock, lockstate); 2913 unhold_object(elm->obj); 2914 /* No need to free anything if process is going down. */ 2915 if (root != NULL) 2916 free(elm); 2917 /* 2918 * We must restart the list traversal after every fini call 2919 * because a dlclose() call from the fini function or from 2920 * another thread might have modified the reference counts. 2921 */ 2922 break; 2923 } 2924 } while (elm != NULL); 2925 errmsg_restore(saved_msg); 2926 } 2927 2928 /* 2929 * Call the initialization functions for each of the objects in 2930 * "list". All of the objects are expected to have non-NULL init 2931 * functions. 2932 */ 2933 static void 2934 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2935 { 2936 Objlist_Entry *elm; 2937 Obj_Entry *obj; 2938 struct dlerror_save *saved_msg; 2939 Elf_Addr *init_addr; 2940 void (*reg)(void (*)(void)); 2941 int index; 2942 2943 /* 2944 * Clean init_scanned flag so that objects can be rechecked and 2945 * possibly initialized earlier if any of vectors called below 2946 * cause the change by using dlopen. 2947 */ 2948 TAILQ_FOREACH(obj, &obj_list, next) { 2949 if (obj->marker) 2950 continue; 2951 obj->init_scanned = false; 2952 } 2953 2954 /* 2955 * Preserve the current error message since an init function might 2956 * call into the dynamic linker and overwrite it. 2957 */ 2958 saved_msg = errmsg_save(); 2959 STAILQ_FOREACH(elm, list, link) { 2960 if (elm->obj->init_done) /* Initialized early. */ 2961 continue; 2962 /* 2963 * Race: other thread might try to use this object before current 2964 * one completes the initialization. Not much can be done here 2965 * without better locking. 2966 */ 2967 elm->obj->init_done = true; 2968 hold_object(elm->obj); 2969 reg = NULL; 2970 if (elm->obj == obj_main && obj_main->crt_no_init) { 2971 reg = (void (*)(void (*)(void)))get_program_var_addr( 2972 "__libc_atexit", lockstate); 2973 } 2974 lock_release(rtld_bind_lock, lockstate); 2975 if (reg != NULL) { 2976 reg(rtld_exit); 2977 rtld_exit_ptr = rtld_nop_exit; 2978 } 2979 2980 /* 2981 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2982 * When this happens, DT_INIT is processed first. 2983 */ 2984 if (elm->obj->init != (Elf_Addr)NULL) { 2985 dbg("calling init function for %s at %p", elm->obj->path, 2986 (void *)elm->obj->init); 2987 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2988 0, 0, elm->obj->path); 2989 call_init_pointer(elm->obj, elm->obj->init); 2990 } 2991 init_addr = (Elf_Addr *)elm->obj->init_array; 2992 if (init_addr != NULL) { 2993 for (index = 0; index < elm->obj->init_array_num; index++) { 2994 if (init_addr[index] != 0 && init_addr[index] != 1) { 2995 dbg("calling init function for %s at %p", elm->obj->path, 2996 (void *)init_addr[index]); 2997 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2998 (void *)init_addr[index], 0, 0, elm->obj->path); 2999 call_init_pointer(elm->obj, init_addr[index]); 3000 } 3001 } 3002 } 3003 wlock_acquire(rtld_bind_lock, lockstate); 3004 unhold_object(elm->obj); 3005 } 3006 errmsg_restore(saved_msg); 3007 } 3008 3009 static void 3010 objlist_clear(Objlist *list) 3011 { 3012 Objlist_Entry *elm; 3013 3014 while (!STAILQ_EMPTY(list)) { 3015 elm = STAILQ_FIRST(list); 3016 STAILQ_REMOVE_HEAD(list, link); 3017 free(elm); 3018 } 3019 } 3020 3021 static Objlist_Entry * 3022 objlist_find(Objlist *list, const Obj_Entry *obj) 3023 { 3024 Objlist_Entry *elm; 3025 3026 STAILQ_FOREACH(elm, list, link) 3027 if (elm->obj == obj) 3028 return elm; 3029 return NULL; 3030 } 3031 3032 static void 3033 objlist_init(Objlist *list) 3034 { 3035 STAILQ_INIT(list); 3036 } 3037 3038 static void 3039 objlist_push_head(Objlist *list, Obj_Entry *obj) 3040 { 3041 Objlist_Entry *elm; 3042 3043 elm = NEW(Objlist_Entry); 3044 elm->obj = obj; 3045 STAILQ_INSERT_HEAD(list, elm, link); 3046 } 3047 3048 static void 3049 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3050 { 3051 Objlist_Entry *elm; 3052 3053 elm = NEW(Objlist_Entry); 3054 elm->obj = obj; 3055 STAILQ_INSERT_TAIL(list, elm, link); 3056 } 3057 3058 static void 3059 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3060 { 3061 Objlist_Entry *elm, *listelm; 3062 3063 STAILQ_FOREACH(listelm, list, link) { 3064 if (listelm->obj == listobj) 3065 break; 3066 } 3067 elm = NEW(Objlist_Entry); 3068 elm->obj = obj; 3069 if (listelm != NULL) 3070 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3071 else 3072 STAILQ_INSERT_TAIL(list, elm, link); 3073 } 3074 3075 static void 3076 objlist_remove(Objlist *list, Obj_Entry *obj) 3077 { 3078 Objlist_Entry *elm; 3079 3080 if ((elm = objlist_find(list, obj)) != NULL) { 3081 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3082 free(elm); 3083 } 3084 } 3085 3086 /* 3087 * Relocate dag rooted in the specified object. 3088 * Returns 0 on success, or -1 on failure. 3089 */ 3090 3091 static int 3092 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3093 int flags, RtldLockState *lockstate) 3094 { 3095 Objlist_Entry *elm; 3096 int error; 3097 3098 error = 0; 3099 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3100 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3101 lockstate); 3102 if (error == -1) 3103 break; 3104 } 3105 return (error); 3106 } 3107 3108 /* 3109 * Prepare for, or clean after, relocating an object marked with 3110 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3111 * segments are remapped read-write. After relocations are done, the 3112 * segment's permissions are returned back to the modes specified in 3113 * the phdrs. If any relocation happened, or always for wired 3114 * program, COW is triggered. 3115 */ 3116 static int 3117 reloc_textrel_prot(Obj_Entry *obj, bool before) 3118 { 3119 const Elf_Phdr *ph; 3120 void *base; 3121 size_t l, sz; 3122 int prot; 3123 3124 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3125 l--, ph++) { 3126 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3127 continue; 3128 base = obj->relocbase + trunc_page(ph->p_vaddr); 3129 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3130 trunc_page(ph->p_vaddr); 3131 prot = before ? (PROT_READ | PROT_WRITE) : 3132 convert_prot(ph->p_flags); 3133 if (mprotect(base, sz, prot) == -1) { 3134 _rtld_error("%s: Cannot write-%sable text segment: %s", 3135 obj->path, before ? "en" : "dis", 3136 rtld_strerror(errno)); 3137 return (-1); 3138 } 3139 } 3140 return (0); 3141 } 3142 3143 /* 3144 * Relocate single object. 3145 * Returns 0 on success, or -1 on failure. 3146 */ 3147 static int 3148 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3149 int flags, RtldLockState *lockstate) 3150 { 3151 3152 if (obj->relocated) 3153 return (0); 3154 obj->relocated = true; 3155 if (obj != rtldobj) 3156 dbg("relocating \"%s\"", obj->path); 3157 3158 if (obj->symtab == NULL || obj->strtab == NULL || 3159 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3160 dbg("object %s has no run-time symbol table", obj->path); 3161 3162 /* There are relocations to the write-protected text segment. */ 3163 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3164 return (-1); 3165 3166 /* Process the non-PLT non-IFUNC relocations. */ 3167 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3168 return (-1); 3169 3170 /* Re-protected the text segment. */ 3171 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3172 return (-1); 3173 3174 /* Set the special PLT or GOT entries. */ 3175 init_pltgot(obj); 3176 3177 /* Process the PLT relocations. */ 3178 if (reloc_plt(obj, flags, lockstate) == -1) 3179 return (-1); 3180 /* Relocate the jump slots if we are doing immediate binding. */ 3181 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3182 lockstate) == -1) 3183 return (-1); 3184 3185 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3186 return (-1); 3187 3188 /* 3189 * Set up the magic number and version in the Obj_Entry. These 3190 * were checked in the crt1.o from the original ElfKit, so we 3191 * set them for backward compatibility. 3192 */ 3193 obj->magic = RTLD_MAGIC; 3194 obj->version = RTLD_VERSION; 3195 3196 return (0); 3197 } 3198 3199 /* 3200 * Relocate newly-loaded shared objects. The argument is a pointer to 3201 * the Obj_Entry for the first such object. All objects from the first 3202 * to the end of the list of objects are relocated. Returns 0 on success, 3203 * or -1 on failure. 3204 */ 3205 static int 3206 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3207 int flags, RtldLockState *lockstate) 3208 { 3209 Obj_Entry *obj; 3210 int error; 3211 3212 for (error = 0, obj = first; obj != NULL; 3213 obj = TAILQ_NEXT(obj, next)) { 3214 if (obj->marker) 3215 continue; 3216 error = relocate_object(obj, bind_now, rtldobj, flags, 3217 lockstate); 3218 if (error == -1) 3219 break; 3220 } 3221 return (error); 3222 } 3223 3224 /* 3225 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3226 * referencing STT_GNU_IFUNC symbols is postponed till the other 3227 * relocations are done. The indirect functions specified as 3228 * ifunc are allowed to call other symbols, so we need to have 3229 * objects relocated before asking for resolution from indirects. 3230 * 3231 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3232 * instead of the usual lazy handling of PLT slots. It is 3233 * consistent with how GNU does it. 3234 */ 3235 static int 3236 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3237 RtldLockState *lockstate) 3238 { 3239 3240 if (obj->ifuncs_resolved) 3241 return (0); 3242 obj->ifuncs_resolved = true; 3243 if (!obj->irelative && !obj->irelative_nonplt && 3244 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3245 !obj->non_plt_gnu_ifunc) 3246 return (0); 3247 if (obj_disable_relro(obj) == -1 || 3248 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3249 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3250 lockstate) == -1) || 3251 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3252 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3253 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3254 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3255 obj_enforce_relro(obj) == -1) 3256 return (-1); 3257 return (0); 3258 } 3259 3260 static int 3261 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3262 RtldLockState *lockstate) 3263 { 3264 Objlist_Entry *elm; 3265 Obj_Entry *obj; 3266 3267 STAILQ_FOREACH(elm, list, link) { 3268 obj = elm->obj; 3269 if (obj->marker) 3270 continue; 3271 if (resolve_object_ifunc(obj, bind_now, flags, 3272 lockstate) == -1) 3273 return (-1); 3274 } 3275 return (0); 3276 } 3277 3278 /* 3279 * Cleanup procedure. It will be called (by the atexit mechanism) just 3280 * before the process exits. 3281 */ 3282 static void 3283 rtld_exit(void) 3284 { 3285 RtldLockState lockstate; 3286 3287 wlock_acquire(rtld_bind_lock, &lockstate); 3288 dbg("rtld_exit()"); 3289 objlist_call_fini(&list_fini, NULL, &lockstate); 3290 /* No need to remove the items from the list, since we are exiting. */ 3291 if (!libmap_disable) 3292 lm_fini(); 3293 lock_release(rtld_bind_lock, &lockstate); 3294 } 3295 3296 static void 3297 rtld_nop_exit(void) 3298 { 3299 } 3300 3301 /* 3302 * Iterate over a search path, translate each element, and invoke the 3303 * callback on the result. 3304 */ 3305 static void * 3306 path_enumerate(const char *path, path_enum_proc callback, 3307 const char *refobj_path, void *arg) 3308 { 3309 const char *trans; 3310 if (path == NULL) 3311 return (NULL); 3312 3313 path += strspn(path, ":;"); 3314 while (*path != '\0') { 3315 size_t len; 3316 char *res; 3317 3318 len = strcspn(path, ":;"); 3319 trans = lm_findn(refobj_path, path, len); 3320 if (trans) 3321 res = callback(trans, strlen(trans), arg); 3322 else 3323 res = callback(path, len, arg); 3324 3325 if (res != NULL) 3326 return (res); 3327 3328 path += len; 3329 path += strspn(path, ":;"); 3330 } 3331 3332 return (NULL); 3333 } 3334 3335 struct try_library_args { 3336 const char *name; 3337 size_t namelen; 3338 char *buffer; 3339 size_t buflen; 3340 int fd; 3341 }; 3342 3343 static void * 3344 try_library_path(const char *dir, size_t dirlen, void *param) 3345 { 3346 struct try_library_args *arg; 3347 int fd; 3348 3349 arg = param; 3350 if (*dir == '/' || trust) { 3351 char *pathname; 3352 3353 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3354 return (NULL); 3355 3356 pathname = arg->buffer; 3357 strncpy(pathname, dir, dirlen); 3358 pathname[dirlen] = '/'; 3359 strcpy(pathname + dirlen + 1, arg->name); 3360 3361 dbg(" Trying \"%s\"", pathname); 3362 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3363 if (fd >= 0) { 3364 dbg(" Opened \"%s\", fd %d", pathname, fd); 3365 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3366 strcpy(pathname, arg->buffer); 3367 arg->fd = fd; 3368 return (pathname); 3369 } else { 3370 dbg(" Failed to open \"%s\": %s", 3371 pathname, rtld_strerror(errno)); 3372 } 3373 } 3374 return (NULL); 3375 } 3376 3377 static char * 3378 search_library_path(const char *name, const char *path, 3379 const char *refobj_path, int *fdp) 3380 { 3381 char *p; 3382 struct try_library_args arg; 3383 3384 if (path == NULL) 3385 return NULL; 3386 3387 arg.name = name; 3388 arg.namelen = strlen(name); 3389 arg.buffer = xmalloc(PATH_MAX); 3390 arg.buflen = PATH_MAX; 3391 arg.fd = -1; 3392 3393 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3394 *fdp = arg.fd; 3395 3396 free(arg.buffer); 3397 3398 return (p); 3399 } 3400 3401 3402 /* 3403 * Finds the library with the given name using the directory descriptors 3404 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3405 * 3406 * Returns a freshly-opened close-on-exec file descriptor for the library, 3407 * or -1 if the library cannot be found. 3408 */ 3409 static char * 3410 search_library_pathfds(const char *name, const char *path, int *fdp) 3411 { 3412 char *envcopy, *fdstr, *found, *last_token; 3413 size_t len; 3414 int dirfd, fd; 3415 3416 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3417 3418 /* Don't load from user-specified libdirs into setuid binaries. */ 3419 if (!trust) 3420 return (NULL); 3421 3422 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3423 if (path == NULL) 3424 return (NULL); 3425 3426 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3427 if (name[0] == '/') { 3428 dbg("Absolute path (%s) passed to %s", name, __func__); 3429 return (NULL); 3430 } 3431 3432 /* 3433 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3434 * copy of the path, as strtok_r rewrites separator tokens 3435 * with '\0'. 3436 */ 3437 found = NULL; 3438 envcopy = xstrdup(path); 3439 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3440 fdstr = strtok_r(NULL, ":", &last_token)) { 3441 dirfd = parse_integer(fdstr); 3442 if (dirfd < 0) { 3443 _rtld_error("failed to parse directory FD: '%s'", 3444 fdstr); 3445 break; 3446 } 3447 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3448 if (fd >= 0) { 3449 *fdp = fd; 3450 len = strlen(fdstr) + strlen(name) + 3; 3451 found = xmalloc(len); 3452 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3453 _rtld_error("error generating '%d/%s'", 3454 dirfd, name); 3455 rtld_die(); 3456 } 3457 dbg("open('%s') => %d", found, fd); 3458 break; 3459 } 3460 } 3461 free(envcopy); 3462 3463 return (found); 3464 } 3465 3466 3467 int 3468 dlclose(void *handle) 3469 { 3470 RtldLockState lockstate; 3471 int error; 3472 3473 wlock_acquire(rtld_bind_lock, &lockstate); 3474 error = dlclose_locked(handle, &lockstate); 3475 lock_release(rtld_bind_lock, &lockstate); 3476 return (error); 3477 } 3478 3479 static int 3480 dlclose_locked(void *handle, RtldLockState *lockstate) 3481 { 3482 Obj_Entry *root; 3483 3484 root = dlcheck(handle); 3485 if (root == NULL) 3486 return -1; 3487 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3488 root->path); 3489 3490 /* Unreference the object and its dependencies. */ 3491 root->dl_refcount--; 3492 3493 if (root->refcount == 1) { 3494 /* 3495 * The object will be no longer referenced, so we must unload it. 3496 * First, call the fini functions. 3497 */ 3498 objlist_call_fini(&list_fini, root, lockstate); 3499 3500 unref_dag(root); 3501 3502 /* Finish cleaning up the newly-unreferenced objects. */ 3503 GDB_STATE(RT_DELETE,&root->linkmap); 3504 unload_object(root, lockstate); 3505 GDB_STATE(RT_CONSISTENT,NULL); 3506 } else 3507 unref_dag(root); 3508 3509 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3510 return 0; 3511 } 3512 3513 char * 3514 dlerror(void) 3515 { 3516 if (*(lockinfo.dlerror_seen()) != 0) 3517 return (NULL); 3518 *lockinfo.dlerror_seen() = 1; 3519 return (lockinfo.dlerror_loc()); 3520 } 3521 3522 /* 3523 * This function is deprecated and has no effect. 3524 */ 3525 void 3526 dllockinit(void *context, 3527 void *(*_lock_create)(void *context) __unused, 3528 void (*_rlock_acquire)(void *lock) __unused, 3529 void (*_wlock_acquire)(void *lock) __unused, 3530 void (*_lock_release)(void *lock) __unused, 3531 void (*_lock_destroy)(void *lock) __unused, 3532 void (*context_destroy)(void *context)) 3533 { 3534 static void *cur_context; 3535 static void (*cur_context_destroy)(void *); 3536 3537 /* Just destroy the context from the previous call, if necessary. */ 3538 if (cur_context_destroy != NULL) 3539 cur_context_destroy(cur_context); 3540 cur_context = context; 3541 cur_context_destroy = context_destroy; 3542 } 3543 3544 void * 3545 dlopen(const char *name, int mode) 3546 { 3547 3548 return (rtld_dlopen(name, -1, mode)); 3549 } 3550 3551 void * 3552 fdlopen(int fd, int mode) 3553 { 3554 3555 return (rtld_dlopen(NULL, fd, mode)); 3556 } 3557 3558 static void * 3559 rtld_dlopen(const char *name, int fd, int mode) 3560 { 3561 RtldLockState lockstate; 3562 int lo_flags; 3563 3564 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3565 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3566 if (ld_tracing != NULL) { 3567 rlock_acquire(rtld_bind_lock, &lockstate); 3568 if (sigsetjmp(lockstate.env, 0) != 0) 3569 lock_upgrade(rtld_bind_lock, &lockstate); 3570 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3571 lock_release(rtld_bind_lock, &lockstate); 3572 } 3573 lo_flags = RTLD_LO_DLOPEN; 3574 if (mode & RTLD_NODELETE) 3575 lo_flags |= RTLD_LO_NODELETE; 3576 if (mode & RTLD_NOLOAD) 3577 lo_flags |= RTLD_LO_NOLOAD; 3578 if (mode & RTLD_DEEPBIND) 3579 lo_flags |= RTLD_LO_DEEPBIND; 3580 if (ld_tracing != NULL) 3581 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3582 3583 return (dlopen_object(name, fd, obj_main, lo_flags, 3584 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3585 } 3586 3587 static void 3588 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3589 { 3590 3591 obj->dl_refcount--; 3592 unref_dag(obj); 3593 if (obj->refcount == 0) 3594 unload_object(obj, lockstate); 3595 } 3596 3597 static Obj_Entry * 3598 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3599 int mode, RtldLockState *lockstate) 3600 { 3601 Obj_Entry *old_obj_tail; 3602 Obj_Entry *obj; 3603 Objlist initlist; 3604 RtldLockState mlockstate; 3605 int result; 3606 3607 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3608 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3609 refobj->path, lo_flags, mode); 3610 objlist_init(&initlist); 3611 3612 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3613 wlock_acquire(rtld_bind_lock, &mlockstate); 3614 lockstate = &mlockstate; 3615 } 3616 GDB_STATE(RT_ADD,NULL); 3617 3618 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3619 obj = NULL; 3620 if (name == NULL && fd == -1) { 3621 obj = obj_main; 3622 obj->refcount++; 3623 } else { 3624 obj = load_object(name, fd, refobj, lo_flags); 3625 } 3626 3627 if (obj) { 3628 obj->dl_refcount++; 3629 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3630 objlist_push_tail(&list_global, obj); 3631 if (globallist_next(old_obj_tail) != NULL) { 3632 /* We loaded something new. */ 3633 assert(globallist_next(old_obj_tail) == obj); 3634 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3635 obj->symbolic = true; 3636 result = 0; 3637 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3638 obj->static_tls && !allocate_tls_offset(obj)) { 3639 _rtld_error("%s: No space available " 3640 "for static Thread Local Storage", obj->path); 3641 result = -1; 3642 } 3643 if (result != -1) 3644 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3645 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3646 init_dag(obj); 3647 ref_dag(obj); 3648 if (result != -1) 3649 result = rtld_verify_versions(&obj->dagmembers); 3650 if (result != -1 && ld_tracing) 3651 goto trace; 3652 if (result == -1 || relocate_object_dag(obj, 3653 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3654 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3655 lockstate) == -1) { 3656 dlopen_cleanup(obj, lockstate); 3657 obj = NULL; 3658 } else if (lo_flags & RTLD_LO_EARLY) { 3659 /* 3660 * Do not call the init functions for early loaded 3661 * filtees. The image is still not initialized enough 3662 * for them to work. 3663 * 3664 * Our object is found by the global object list and 3665 * will be ordered among all init calls done right 3666 * before transferring control to main. 3667 */ 3668 } else { 3669 /* Make list of init functions to call. */ 3670 initlist_add_objects(obj, obj, &initlist); 3671 } 3672 /* 3673 * Process all no_delete or global objects here, given 3674 * them own DAGs to prevent their dependencies from being 3675 * unloaded. This has to be done after we have loaded all 3676 * of the dependencies, so that we do not miss any. 3677 */ 3678 if (obj != NULL) 3679 process_z(obj); 3680 } else { 3681 /* 3682 * Bump the reference counts for objects on this DAG. If 3683 * this is the first dlopen() call for the object that was 3684 * already loaded as a dependency, initialize the dag 3685 * starting at it. 3686 */ 3687 init_dag(obj); 3688 ref_dag(obj); 3689 3690 if ((lo_flags & RTLD_LO_TRACE) != 0) 3691 goto trace; 3692 } 3693 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3694 obj->z_nodelete) && !obj->ref_nodel) { 3695 dbg("obj %s nodelete", obj->path); 3696 ref_dag(obj); 3697 obj->z_nodelete = obj->ref_nodel = true; 3698 } 3699 } 3700 3701 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3702 name); 3703 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3704 3705 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3706 map_stacks_exec(lockstate); 3707 if (obj != NULL) 3708 distribute_static_tls(&initlist, lockstate); 3709 } 3710 3711 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3712 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3713 lockstate) == -1) { 3714 objlist_clear(&initlist); 3715 dlopen_cleanup(obj, lockstate); 3716 if (lockstate == &mlockstate) 3717 lock_release(rtld_bind_lock, lockstate); 3718 return (NULL); 3719 } 3720 3721 if (!(lo_flags & RTLD_LO_EARLY)) { 3722 /* Call the init functions. */ 3723 objlist_call_init(&initlist, lockstate); 3724 } 3725 objlist_clear(&initlist); 3726 if (lockstate == &mlockstate) 3727 lock_release(rtld_bind_lock, lockstate); 3728 return obj; 3729 trace: 3730 trace_loaded_objects(obj); 3731 if (lockstate == &mlockstate) 3732 lock_release(rtld_bind_lock, lockstate); 3733 exit(0); 3734 } 3735 3736 static void * 3737 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3738 int flags) 3739 { 3740 DoneList donelist; 3741 const Obj_Entry *obj, *defobj; 3742 const Elf_Sym *def; 3743 SymLook req; 3744 RtldLockState lockstate; 3745 tls_index ti; 3746 void *sym; 3747 int res; 3748 3749 def = NULL; 3750 defobj = NULL; 3751 symlook_init(&req, name); 3752 req.ventry = ve; 3753 req.flags = flags | SYMLOOK_IN_PLT; 3754 req.lockstate = &lockstate; 3755 3756 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3757 rlock_acquire(rtld_bind_lock, &lockstate); 3758 if (sigsetjmp(lockstate.env, 0) != 0) 3759 lock_upgrade(rtld_bind_lock, &lockstate); 3760 if (handle == NULL || handle == RTLD_NEXT || 3761 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3762 3763 if ((obj = obj_from_addr(retaddr)) == NULL) { 3764 _rtld_error("Cannot determine caller's shared object"); 3765 lock_release(rtld_bind_lock, &lockstate); 3766 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3767 return NULL; 3768 } 3769 if (handle == NULL) { /* Just the caller's shared object. */ 3770 res = symlook_obj(&req, obj); 3771 if (res == 0) { 3772 def = req.sym_out; 3773 defobj = req.defobj_out; 3774 } 3775 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3776 handle == RTLD_SELF) { /* ... caller included */ 3777 if (handle == RTLD_NEXT) 3778 obj = globallist_next(obj); 3779 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3780 if (obj->marker) 3781 continue; 3782 res = symlook_obj(&req, obj); 3783 if (res == 0) { 3784 if (def == NULL || (ld_dynamic_weak && 3785 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3786 def = req.sym_out; 3787 defobj = req.defobj_out; 3788 if (!ld_dynamic_weak || 3789 ELF_ST_BIND(def->st_info) != STB_WEAK) 3790 break; 3791 } 3792 } 3793 } 3794 /* 3795 * Search the dynamic linker itself, and possibly resolve the 3796 * symbol from there. This is how the application links to 3797 * dynamic linker services such as dlopen. 3798 * Note that we ignore ld_dynamic_weak == false case, 3799 * always overriding weak symbols by rtld definitions. 3800 */ 3801 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3802 res = symlook_obj(&req, &obj_rtld); 3803 if (res == 0) { 3804 def = req.sym_out; 3805 defobj = req.defobj_out; 3806 } 3807 } 3808 } else { 3809 assert(handle == RTLD_DEFAULT); 3810 res = symlook_default(&req, obj); 3811 if (res == 0) { 3812 defobj = req.defobj_out; 3813 def = req.sym_out; 3814 } 3815 } 3816 } else { 3817 if ((obj = dlcheck(handle)) == NULL) { 3818 lock_release(rtld_bind_lock, &lockstate); 3819 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3820 return NULL; 3821 } 3822 3823 donelist_init(&donelist); 3824 if (obj->mainprog) { 3825 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3826 res = symlook_global(&req, &donelist); 3827 if (res == 0) { 3828 def = req.sym_out; 3829 defobj = req.defobj_out; 3830 } 3831 /* 3832 * Search the dynamic linker itself, and possibly resolve the 3833 * symbol from there. This is how the application links to 3834 * dynamic linker services such as dlopen. 3835 */ 3836 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3837 res = symlook_obj(&req, &obj_rtld); 3838 if (res == 0) { 3839 def = req.sym_out; 3840 defobj = req.defobj_out; 3841 } 3842 } 3843 } 3844 else { 3845 /* Search the whole DAG rooted at the given object. */ 3846 res = symlook_list(&req, &obj->dagmembers, &donelist); 3847 if (res == 0) { 3848 def = req.sym_out; 3849 defobj = req.defobj_out; 3850 } 3851 } 3852 } 3853 3854 if (def != NULL) { 3855 lock_release(rtld_bind_lock, &lockstate); 3856 3857 /* 3858 * The value required by the caller is derived from the value 3859 * of the symbol. this is simply the relocated value of the 3860 * symbol. 3861 */ 3862 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3863 sym = make_function_pointer(def, defobj); 3864 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3865 sym = rtld_resolve_ifunc(defobj, def); 3866 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3867 ti.ti_module = defobj->tlsindex; 3868 ti.ti_offset = def->st_value; 3869 sym = __tls_get_addr(&ti); 3870 } else 3871 sym = defobj->relocbase + def->st_value; 3872 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3873 return (sym); 3874 } 3875 3876 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3877 ve != NULL ? ve->name : ""); 3878 lock_release(rtld_bind_lock, &lockstate); 3879 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3880 return NULL; 3881 } 3882 3883 void * 3884 dlsym(void *handle, const char *name) 3885 { 3886 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3887 SYMLOOK_DLSYM); 3888 } 3889 3890 dlfunc_t 3891 dlfunc(void *handle, const char *name) 3892 { 3893 union { 3894 void *d; 3895 dlfunc_t f; 3896 } rv; 3897 3898 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3899 SYMLOOK_DLSYM); 3900 return (rv.f); 3901 } 3902 3903 void * 3904 dlvsym(void *handle, const char *name, const char *version) 3905 { 3906 Ver_Entry ventry; 3907 3908 ventry.name = version; 3909 ventry.file = NULL; 3910 ventry.hash = elf_hash(version); 3911 ventry.flags= 0; 3912 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3913 SYMLOOK_DLSYM); 3914 } 3915 3916 int 3917 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3918 { 3919 const Obj_Entry *obj; 3920 RtldLockState lockstate; 3921 3922 rlock_acquire(rtld_bind_lock, &lockstate); 3923 obj = obj_from_addr(addr); 3924 if (obj == NULL) { 3925 _rtld_error("No shared object contains address"); 3926 lock_release(rtld_bind_lock, &lockstate); 3927 return (0); 3928 } 3929 rtld_fill_dl_phdr_info(obj, phdr_info); 3930 lock_release(rtld_bind_lock, &lockstate); 3931 return (1); 3932 } 3933 3934 int 3935 dladdr(const void *addr, Dl_info *info) 3936 { 3937 const Obj_Entry *obj; 3938 const Elf_Sym *def; 3939 void *symbol_addr; 3940 unsigned long symoffset; 3941 RtldLockState lockstate; 3942 3943 rlock_acquire(rtld_bind_lock, &lockstate); 3944 obj = obj_from_addr(addr); 3945 if (obj == NULL) { 3946 _rtld_error("No shared object contains address"); 3947 lock_release(rtld_bind_lock, &lockstate); 3948 return 0; 3949 } 3950 info->dli_fname = obj->path; 3951 info->dli_fbase = obj->mapbase; 3952 info->dli_saddr = (void *)0; 3953 info->dli_sname = NULL; 3954 3955 /* 3956 * Walk the symbol list looking for the symbol whose address is 3957 * closest to the address sent in. 3958 */ 3959 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3960 def = obj->symtab + symoffset; 3961 3962 /* 3963 * For skip the symbol if st_shndx is either SHN_UNDEF or 3964 * SHN_COMMON. 3965 */ 3966 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3967 continue; 3968 3969 /* 3970 * If the symbol is greater than the specified address, or if it 3971 * is further away from addr than the current nearest symbol, 3972 * then reject it. 3973 */ 3974 symbol_addr = obj->relocbase + def->st_value; 3975 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3976 continue; 3977 3978 /* Update our idea of the nearest symbol. */ 3979 info->dli_sname = obj->strtab + def->st_name; 3980 info->dli_saddr = symbol_addr; 3981 3982 /* Exact match? */ 3983 if (info->dli_saddr == addr) 3984 break; 3985 } 3986 lock_release(rtld_bind_lock, &lockstate); 3987 return 1; 3988 } 3989 3990 int 3991 dlinfo(void *handle, int request, void *p) 3992 { 3993 const Obj_Entry *obj; 3994 RtldLockState lockstate; 3995 int error; 3996 3997 rlock_acquire(rtld_bind_lock, &lockstate); 3998 3999 if (handle == NULL || handle == RTLD_SELF) { 4000 void *retaddr; 4001 4002 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4003 if ((obj = obj_from_addr(retaddr)) == NULL) 4004 _rtld_error("Cannot determine caller's shared object"); 4005 } else 4006 obj = dlcheck(handle); 4007 4008 if (obj == NULL) { 4009 lock_release(rtld_bind_lock, &lockstate); 4010 return (-1); 4011 } 4012 4013 error = 0; 4014 switch (request) { 4015 case RTLD_DI_LINKMAP: 4016 *((struct link_map const **)p) = &obj->linkmap; 4017 break; 4018 case RTLD_DI_ORIGIN: 4019 error = rtld_dirname(obj->path, p); 4020 break; 4021 4022 case RTLD_DI_SERINFOSIZE: 4023 case RTLD_DI_SERINFO: 4024 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4025 break; 4026 4027 default: 4028 _rtld_error("Invalid request %d passed to dlinfo()", request); 4029 error = -1; 4030 } 4031 4032 lock_release(rtld_bind_lock, &lockstate); 4033 4034 return (error); 4035 } 4036 4037 static void 4038 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4039 { 4040 Elf_Addr **dtvp; 4041 4042 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4043 phdr_info->dlpi_name = obj->path; 4044 phdr_info->dlpi_phdr = obj->phdr; 4045 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4046 phdr_info->dlpi_tls_modid = obj->tlsindex; 4047 dtvp = _get_tp(); 4048 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4049 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4050 phdr_info->dlpi_adds = obj_loads; 4051 phdr_info->dlpi_subs = obj_loads - obj_count; 4052 } 4053 4054 int 4055 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4056 { 4057 struct dl_phdr_info phdr_info; 4058 Obj_Entry *obj, marker; 4059 RtldLockState bind_lockstate, phdr_lockstate; 4060 int error; 4061 4062 init_marker(&marker); 4063 error = 0; 4064 4065 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4066 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4067 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4068 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4069 rtld_fill_dl_phdr_info(obj, &phdr_info); 4070 hold_object(obj); 4071 lock_release(rtld_bind_lock, &bind_lockstate); 4072 4073 error = callback(&phdr_info, sizeof phdr_info, param); 4074 4075 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4076 unhold_object(obj); 4077 obj = globallist_next(&marker); 4078 TAILQ_REMOVE(&obj_list, &marker, next); 4079 if (error != 0) { 4080 lock_release(rtld_bind_lock, &bind_lockstate); 4081 lock_release(rtld_phdr_lock, &phdr_lockstate); 4082 return (error); 4083 } 4084 } 4085 4086 if (error == 0) { 4087 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4088 lock_release(rtld_bind_lock, &bind_lockstate); 4089 error = callback(&phdr_info, sizeof(phdr_info), param); 4090 } 4091 lock_release(rtld_phdr_lock, &phdr_lockstate); 4092 return (error); 4093 } 4094 4095 static void * 4096 fill_search_info(const char *dir, size_t dirlen, void *param) 4097 { 4098 struct fill_search_info_args *arg; 4099 4100 arg = param; 4101 4102 if (arg->request == RTLD_DI_SERINFOSIZE) { 4103 arg->serinfo->dls_cnt ++; 4104 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4105 } else { 4106 struct dl_serpath *s_entry; 4107 4108 s_entry = arg->serpath; 4109 s_entry->dls_name = arg->strspace; 4110 s_entry->dls_flags = arg->flags; 4111 4112 strncpy(arg->strspace, dir, dirlen); 4113 arg->strspace[dirlen] = '\0'; 4114 4115 arg->strspace += dirlen + 1; 4116 arg->serpath++; 4117 } 4118 4119 return (NULL); 4120 } 4121 4122 static int 4123 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4124 { 4125 struct dl_serinfo _info; 4126 struct fill_search_info_args args; 4127 4128 args.request = RTLD_DI_SERINFOSIZE; 4129 args.serinfo = &_info; 4130 4131 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4132 _info.dls_cnt = 0; 4133 4134 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4135 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4136 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4137 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4138 if (!obj->z_nodeflib) 4139 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4140 4141 4142 if (request == RTLD_DI_SERINFOSIZE) { 4143 info->dls_size = _info.dls_size; 4144 info->dls_cnt = _info.dls_cnt; 4145 return (0); 4146 } 4147 4148 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4149 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4150 return (-1); 4151 } 4152 4153 args.request = RTLD_DI_SERINFO; 4154 args.serinfo = info; 4155 args.serpath = &info->dls_serpath[0]; 4156 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4157 4158 args.flags = LA_SER_RUNPATH; 4159 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4160 return (-1); 4161 4162 args.flags = LA_SER_LIBPATH; 4163 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4164 return (-1); 4165 4166 args.flags = LA_SER_RUNPATH; 4167 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4168 return (-1); 4169 4170 args.flags = LA_SER_CONFIG; 4171 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4172 != NULL) 4173 return (-1); 4174 4175 args.flags = LA_SER_DEFAULT; 4176 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4177 fill_search_info, NULL, &args) != NULL) 4178 return (-1); 4179 return (0); 4180 } 4181 4182 static int 4183 rtld_dirname(const char *path, char *bname) 4184 { 4185 const char *endp; 4186 4187 /* Empty or NULL string gets treated as "." */ 4188 if (path == NULL || *path == '\0') { 4189 bname[0] = '.'; 4190 bname[1] = '\0'; 4191 return (0); 4192 } 4193 4194 /* Strip trailing slashes */ 4195 endp = path + strlen(path) - 1; 4196 while (endp > path && *endp == '/') 4197 endp--; 4198 4199 /* Find the start of the dir */ 4200 while (endp > path && *endp != '/') 4201 endp--; 4202 4203 /* Either the dir is "/" or there are no slashes */ 4204 if (endp == path) { 4205 bname[0] = *endp == '/' ? '/' : '.'; 4206 bname[1] = '\0'; 4207 return (0); 4208 } else { 4209 do { 4210 endp--; 4211 } while (endp > path && *endp == '/'); 4212 } 4213 4214 if (endp - path + 2 > PATH_MAX) 4215 { 4216 _rtld_error("Filename is too long: %s", path); 4217 return(-1); 4218 } 4219 4220 strncpy(bname, path, endp - path + 1); 4221 bname[endp - path + 1] = '\0'; 4222 return (0); 4223 } 4224 4225 static int 4226 rtld_dirname_abs(const char *path, char *base) 4227 { 4228 char *last; 4229 4230 if (realpath(path, base) == NULL) { 4231 _rtld_error("realpath \"%s\" failed (%s)", path, 4232 rtld_strerror(errno)); 4233 return (-1); 4234 } 4235 dbg("%s -> %s", path, base); 4236 last = strrchr(base, '/'); 4237 if (last == NULL) { 4238 _rtld_error("non-abs result from realpath \"%s\"", path); 4239 return (-1); 4240 } 4241 if (last != base) 4242 *last = '\0'; 4243 return (0); 4244 } 4245 4246 static void 4247 linkmap_add(Obj_Entry *obj) 4248 { 4249 struct link_map *l, *prev; 4250 4251 l = &obj->linkmap; 4252 l->l_name = obj->path; 4253 l->l_base = obj->mapbase; 4254 l->l_ld = obj->dynamic; 4255 l->l_addr = obj->relocbase; 4256 4257 if (r_debug.r_map == NULL) { 4258 r_debug.r_map = l; 4259 return; 4260 } 4261 4262 /* 4263 * Scan to the end of the list, but not past the entry for the 4264 * dynamic linker, which we want to keep at the very end. 4265 */ 4266 for (prev = r_debug.r_map; 4267 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4268 prev = prev->l_next) 4269 ; 4270 4271 /* Link in the new entry. */ 4272 l->l_prev = prev; 4273 l->l_next = prev->l_next; 4274 if (l->l_next != NULL) 4275 l->l_next->l_prev = l; 4276 prev->l_next = l; 4277 } 4278 4279 static void 4280 linkmap_delete(Obj_Entry *obj) 4281 { 4282 struct link_map *l; 4283 4284 l = &obj->linkmap; 4285 if (l->l_prev == NULL) { 4286 if ((r_debug.r_map = l->l_next) != NULL) 4287 l->l_next->l_prev = NULL; 4288 return; 4289 } 4290 4291 if ((l->l_prev->l_next = l->l_next) != NULL) 4292 l->l_next->l_prev = l->l_prev; 4293 } 4294 4295 /* 4296 * Function for the debugger to set a breakpoint on to gain control. 4297 * 4298 * The two parameters allow the debugger to easily find and determine 4299 * what the runtime loader is doing and to whom it is doing it. 4300 * 4301 * When the loadhook trap is hit (r_debug_state, set at program 4302 * initialization), the arguments can be found on the stack: 4303 * 4304 * +8 struct link_map *m 4305 * +4 struct r_debug *rd 4306 * +0 RetAddr 4307 */ 4308 void 4309 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4310 { 4311 /* 4312 * The following is a hack to force the compiler to emit calls to 4313 * this function, even when optimizing. If the function is empty, 4314 * the compiler is not obliged to emit any code for calls to it, 4315 * even when marked __noinline. However, gdb depends on those 4316 * calls being made. 4317 */ 4318 __compiler_membar(); 4319 } 4320 4321 /* 4322 * A function called after init routines have completed. This can be used to 4323 * break before a program's entry routine is called, and can be used when 4324 * main is not available in the symbol table. 4325 */ 4326 void 4327 _r_debug_postinit(struct link_map *m __unused) 4328 { 4329 4330 /* See r_debug_state(). */ 4331 __compiler_membar(); 4332 } 4333 4334 static void 4335 release_object(Obj_Entry *obj) 4336 { 4337 4338 if (obj->holdcount > 0) { 4339 obj->unholdfree = true; 4340 return; 4341 } 4342 munmap(obj->mapbase, obj->mapsize); 4343 linkmap_delete(obj); 4344 obj_free(obj); 4345 } 4346 4347 /* 4348 * Get address of the pointer variable in the main program. 4349 * Prefer non-weak symbol over the weak one. 4350 */ 4351 static const void ** 4352 get_program_var_addr(const char *name, RtldLockState *lockstate) 4353 { 4354 SymLook req; 4355 DoneList donelist; 4356 4357 symlook_init(&req, name); 4358 req.lockstate = lockstate; 4359 donelist_init(&donelist); 4360 if (symlook_global(&req, &donelist) != 0) 4361 return (NULL); 4362 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4363 return ((const void **)make_function_pointer(req.sym_out, 4364 req.defobj_out)); 4365 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4366 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4367 else 4368 return ((const void **)(req.defobj_out->relocbase + 4369 req.sym_out->st_value)); 4370 } 4371 4372 /* 4373 * Set a pointer variable in the main program to the given value. This 4374 * is used to set key variables such as "environ" before any of the 4375 * init functions are called. 4376 */ 4377 static void 4378 set_program_var(const char *name, const void *value) 4379 { 4380 const void **addr; 4381 4382 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4383 dbg("\"%s\": *%p <-- %p", name, addr, value); 4384 *addr = value; 4385 } 4386 } 4387 4388 /* 4389 * Search the global objects, including dependencies and main object, 4390 * for the given symbol. 4391 */ 4392 static int 4393 symlook_global(SymLook *req, DoneList *donelist) 4394 { 4395 SymLook req1; 4396 const Objlist_Entry *elm; 4397 int res; 4398 4399 symlook_init_from_req(&req1, req); 4400 4401 /* Search all objects loaded at program start up. */ 4402 if (req->defobj_out == NULL || (ld_dynamic_weak && 4403 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4404 res = symlook_list(&req1, &list_main, donelist); 4405 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4406 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4407 req->sym_out = req1.sym_out; 4408 req->defobj_out = req1.defobj_out; 4409 assert(req->defobj_out != NULL); 4410 } 4411 } 4412 4413 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4414 STAILQ_FOREACH(elm, &list_global, link) { 4415 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4416 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4417 break; 4418 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4419 if (res == 0 && (req->defobj_out == NULL || 4420 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4421 req->sym_out = req1.sym_out; 4422 req->defobj_out = req1.defobj_out; 4423 assert(req->defobj_out != NULL); 4424 } 4425 } 4426 4427 return (req->sym_out != NULL ? 0 : ESRCH); 4428 } 4429 4430 /* 4431 * Given a symbol name in a referencing object, find the corresponding 4432 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4433 * no definition was found. Returns a pointer to the Obj_Entry of the 4434 * defining object via the reference parameter DEFOBJ_OUT. 4435 */ 4436 static int 4437 symlook_default(SymLook *req, const Obj_Entry *refobj) 4438 { 4439 DoneList donelist; 4440 const Objlist_Entry *elm; 4441 SymLook req1; 4442 int res; 4443 4444 donelist_init(&donelist); 4445 symlook_init_from_req(&req1, req); 4446 4447 /* 4448 * Look first in the referencing object if linked symbolically, 4449 * and similarly handle protected symbols. 4450 */ 4451 res = symlook_obj(&req1, refobj); 4452 if (res == 0 && (refobj->symbolic || 4453 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4454 req->sym_out = req1.sym_out; 4455 req->defobj_out = req1.defobj_out; 4456 assert(req->defobj_out != NULL); 4457 } 4458 if (refobj->symbolic || req->defobj_out != NULL) 4459 donelist_check(&donelist, refobj); 4460 4461 symlook_global(req, &donelist); 4462 4463 /* Search all dlopened DAGs containing the referencing object. */ 4464 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4465 if (req->sym_out != NULL && (!ld_dynamic_weak || 4466 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4467 break; 4468 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4469 if (res == 0 && (req->sym_out == NULL || 4470 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4471 req->sym_out = req1.sym_out; 4472 req->defobj_out = req1.defobj_out; 4473 assert(req->defobj_out != NULL); 4474 } 4475 } 4476 4477 /* 4478 * Search the dynamic linker itself, and possibly resolve the 4479 * symbol from there. This is how the application links to 4480 * dynamic linker services such as dlopen. 4481 */ 4482 if (req->sym_out == NULL || 4483 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4484 res = symlook_obj(&req1, &obj_rtld); 4485 if (res == 0) { 4486 req->sym_out = req1.sym_out; 4487 req->defobj_out = req1.defobj_out; 4488 assert(req->defobj_out != NULL); 4489 } 4490 } 4491 4492 return (req->sym_out != NULL ? 0 : ESRCH); 4493 } 4494 4495 static int 4496 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4497 { 4498 const Elf_Sym *def; 4499 const Obj_Entry *defobj; 4500 const Objlist_Entry *elm; 4501 SymLook req1; 4502 int res; 4503 4504 def = NULL; 4505 defobj = NULL; 4506 STAILQ_FOREACH(elm, objlist, link) { 4507 if (donelist_check(dlp, elm->obj)) 4508 continue; 4509 symlook_init_from_req(&req1, req); 4510 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4511 if (def == NULL || (ld_dynamic_weak && 4512 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4513 def = req1.sym_out; 4514 defobj = req1.defobj_out; 4515 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4516 break; 4517 } 4518 } 4519 } 4520 if (def != NULL) { 4521 req->sym_out = def; 4522 req->defobj_out = defobj; 4523 return (0); 4524 } 4525 return (ESRCH); 4526 } 4527 4528 /* 4529 * Search the chain of DAGS cointed to by the given Needed_Entry 4530 * for a symbol of the given name. Each DAG is scanned completely 4531 * before advancing to the next one. Returns a pointer to the symbol, 4532 * or NULL if no definition was found. 4533 */ 4534 static int 4535 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4536 { 4537 const Elf_Sym *def; 4538 const Needed_Entry *n; 4539 const Obj_Entry *defobj; 4540 SymLook req1; 4541 int res; 4542 4543 def = NULL; 4544 defobj = NULL; 4545 symlook_init_from_req(&req1, req); 4546 for (n = needed; n != NULL; n = n->next) { 4547 if (n->obj == NULL || 4548 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4549 continue; 4550 if (def == NULL || (ld_dynamic_weak && 4551 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4552 def = req1.sym_out; 4553 defobj = req1.defobj_out; 4554 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4555 break; 4556 } 4557 } 4558 if (def != NULL) { 4559 req->sym_out = def; 4560 req->defobj_out = defobj; 4561 return (0); 4562 } 4563 return (ESRCH); 4564 } 4565 4566 /* 4567 * Search the symbol table of a single shared object for a symbol of 4568 * the given name and version, if requested. Returns a pointer to the 4569 * symbol, or NULL if no definition was found. If the object is 4570 * filter, return filtered symbol from filtee. 4571 * 4572 * The symbol's hash value is passed in for efficiency reasons; that 4573 * eliminates many recomputations of the hash value. 4574 */ 4575 int 4576 symlook_obj(SymLook *req, const Obj_Entry *obj) 4577 { 4578 DoneList donelist; 4579 SymLook req1; 4580 int flags, res, mres; 4581 4582 /* 4583 * If there is at least one valid hash at this point, we prefer to 4584 * use the faster GNU version if available. 4585 */ 4586 if (obj->valid_hash_gnu) 4587 mres = symlook_obj1_gnu(req, obj); 4588 else if (obj->valid_hash_sysv) 4589 mres = symlook_obj1_sysv(req, obj); 4590 else 4591 return (EINVAL); 4592 4593 if (mres == 0) { 4594 if (obj->needed_filtees != NULL) { 4595 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4596 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4597 donelist_init(&donelist); 4598 symlook_init_from_req(&req1, req); 4599 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4600 if (res == 0) { 4601 req->sym_out = req1.sym_out; 4602 req->defobj_out = req1.defobj_out; 4603 } 4604 return (res); 4605 } 4606 if (obj->needed_aux_filtees != NULL) { 4607 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4608 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4609 donelist_init(&donelist); 4610 symlook_init_from_req(&req1, req); 4611 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4612 if (res == 0) { 4613 req->sym_out = req1.sym_out; 4614 req->defobj_out = req1.defobj_out; 4615 return (res); 4616 } 4617 } 4618 } 4619 return (mres); 4620 } 4621 4622 /* Symbol match routine common to both hash functions */ 4623 static bool 4624 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4625 const unsigned long symnum) 4626 { 4627 Elf_Versym verndx; 4628 const Elf_Sym *symp; 4629 const char *strp; 4630 4631 symp = obj->symtab + symnum; 4632 strp = obj->strtab + symp->st_name; 4633 4634 switch (ELF_ST_TYPE(symp->st_info)) { 4635 case STT_FUNC: 4636 case STT_NOTYPE: 4637 case STT_OBJECT: 4638 case STT_COMMON: 4639 case STT_GNU_IFUNC: 4640 if (symp->st_value == 0) 4641 return (false); 4642 /* fallthrough */ 4643 case STT_TLS: 4644 if (symp->st_shndx != SHN_UNDEF) 4645 break; 4646 #ifndef __mips__ 4647 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4648 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4649 break; 4650 #endif 4651 /* fallthrough */ 4652 default: 4653 return (false); 4654 } 4655 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4656 return (false); 4657 4658 if (req->ventry == NULL) { 4659 if (obj->versyms != NULL) { 4660 verndx = VER_NDX(obj->versyms[symnum]); 4661 if (verndx > obj->vernum) { 4662 _rtld_error( 4663 "%s: symbol %s references wrong version %d", 4664 obj->path, obj->strtab + symnum, verndx); 4665 return (false); 4666 } 4667 /* 4668 * If we are not called from dlsym (i.e. this 4669 * is a normal relocation from unversioned 4670 * binary), accept the symbol immediately if 4671 * it happens to have first version after this 4672 * shared object became versioned. Otherwise, 4673 * if symbol is versioned and not hidden, 4674 * remember it. If it is the only symbol with 4675 * this name exported by the shared object, it 4676 * will be returned as a match by the calling 4677 * function. If symbol is global (verndx < 2) 4678 * accept it unconditionally. 4679 */ 4680 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4681 verndx == VER_NDX_GIVEN) { 4682 result->sym_out = symp; 4683 return (true); 4684 } 4685 else if (verndx >= VER_NDX_GIVEN) { 4686 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4687 == 0) { 4688 if (result->vsymp == NULL) 4689 result->vsymp = symp; 4690 result->vcount++; 4691 } 4692 return (false); 4693 } 4694 } 4695 result->sym_out = symp; 4696 return (true); 4697 } 4698 if (obj->versyms == NULL) { 4699 if (object_match_name(obj, req->ventry->name)) { 4700 _rtld_error("%s: object %s should provide version %s " 4701 "for symbol %s", obj_rtld.path, obj->path, 4702 req->ventry->name, obj->strtab + symnum); 4703 return (false); 4704 } 4705 } else { 4706 verndx = VER_NDX(obj->versyms[symnum]); 4707 if (verndx > obj->vernum) { 4708 _rtld_error("%s: symbol %s references wrong version %d", 4709 obj->path, obj->strtab + symnum, verndx); 4710 return (false); 4711 } 4712 if (obj->vertab[verndx].hash != req->ventry->hash || 4713 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4714 /* 4715 * Version does not match. Look if this is a 4716 * global symbol and if it is not hidden. If 4717 * global symbol (verndx < 2) is available, 4718 * use it. Do not return symbol if we are 4719 * called by dlvsym, because dlvsym looks for 4720 * a specific version and default one is not 4721 * what dlvsym wants. 4722 */ 4723 if ((req->flags & SYMLOOK_DLSYM) || 4724 (verndx >= VER_NDX_GIVEN) || 4725 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4726 return (false); 4727 } 4728 } 4729 result->sym_out = symp; 4730 return (true); 4731 } 4732 4733 /* 4734 * Search for symbol using SysV hash function. 4735 * obj->buckets is known not to be NULL at this point; the test for this was 4736 * performed with the obj->valid_hash_sysv assignment. 4737 */ 4738 static int 4739 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4740 { 4741 unsigned long symnum; 4742 Sym_Match_Result matchres; 4743 4744 matchres.sym_out = NULL; 4745 matchres.vsymp = NULL; 4746 matchres.vcount = 0; 4747 4748 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4749 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4750 if (symnum >= obj->nchains) 4751 return (ESRCH); /* Bad object */ 4752 4753 if (matched_symbol(req, obj, &matchres, symnum)) { 4754 req->sym_out = matchres.sym_out; 4755 req->defobj_out = obj; 4756 return (0); 4757 } 4758 } 4759 if (matchres.vcount == 1) { 4760 req->sym_out = matchres.vsymp; 4761 req->defobj_out = obj; 4762 return (0); 4763 } 4764 return (ESRCH); 4765 } 4766 4767 /* Search for symbol using GNU hash function */ 4768 static int 4769 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4770 { 4771 Elf_Addr bloom_word; 4772 const Elf32_Word *hashval; 4773 Elf32_Word bucket; 4774 Sym_Match_Result matchres; 4775 unsigned int h1, h2; 4776 unsigned long symnum; 4777 4778 matchres.sym_out = NULL; 4779 matchres.vsymp = NULL; 4780 matchres.vcount = 0; 4781 4782 /* Pick right bitmask word from Bloom filter array */ 4783 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4784 obj->maskwords_bm_gnu]; 4785 4786 /* Calculate modulus word size of gnu hash and its derivative */ 4787 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4788 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4789 4790 /* Filter out the "definitely not in set" queries */ 4791 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4792 return (ESRCH); 4793 4794 /* Locate hash chain and corresponding value element*/ 4795 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4796 if (bucket == 0) 4797 return (ESRCH); 4798 hashval = &obj->chain_zero_gnu[bucket]; 4799 do { 4800 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4801 symnum = hashval - obj->chain_zero_gnu; 4802 if (matched_symbol(req, obj, &matchres, symnum)) { 4803 req->sym_out = matchres.sym_out; 4804 req->defobj_out = obj; 4805 return (0); 4806 } 4807 } 4808 } while ((*hashval++ & 1) == 0); 4809 if (matchres.vcount == 1) { 4810 req->sym_out = matchres.vsymp; 4811 req->defobj_out = obj; 4812 return (0); 4813 } 4814 return (ESRCH); 4815 } 4816 4817 static void 4818 trace_loaded_objects(Obj_Entry *obj) 4819 { 4820 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4821 int c; 4822 4823 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4824 NULL) 4825 main_local = ""; 4826 4827 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4828 fmt1 = "\t%o => %p (%x)\n"; 4829 4830 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4831 fmt2 = "\t%o (%x)\n"; 4832 4833 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4834 4835 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4836 Needed_Entry *needed; 4837 const char *name, *path; 4838 bool is_lib; 4839 4840 if (obj->marker) 4841 continue; 4842 if (list_containers && obj->needed != NULL) 4843 rtld_printf("%s:\n", obj->path); 4844 for (needed = obj->needed; needed; needed = needed->next) { 4845 if (needed->obj != NULL) { 4846 if (needed->obj->traced && !list_containers) 4847 continue; 4848 needed->obj->traced = true; 4849 path = needed->obj->path; 4850 } else 4851 path = "not found"; 4852 4853 name = obj->strtab + needed->name; 4854 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4855 4856 fmt = is_lib ? fmt1 : fmt2; 4857 while ((c = *fmt++) != '\0') { 4858 switch (c) { 4859 default: 4860 rtld_putchar(c); 4861 continue; 4862 case '\\': 4863 switch (c = *fmt) { 4864 case '\0': 4865 continue; 4866 case 'n': 4867 rtld_putchar('\n'); 4868 break; 4869 case 't': 4870 rtld_putchar('\t'); 4871 break; 4872 } 4873 break; 4874 case '%': 4875 switch (c = *fmt) { 4876 case '\0': 4877 continue; 4878 case '%': 4879 default: 4880 rtld_putchar(c); 4881 break; 4882 case 'A': 4883 rtld_putstr(main_local); 4884 break; 4885 case 'a': 4886 rtld_putstr(obj_main->path); 4887 break; 4888 case 'o': 4889 rtld_putstr(name); 4890 break; 4891 #if 0 4892 case 'm': 4893 rtld_printf("%d", sodp->sod_major); 4894 break; 4895 case 'n': 4896 rtld_printf("%d", sodp->sod_minor); 4897 break; 4898 #endif 4899 case 'p': 4900 rtld_putstr(path); 4901 break; 4902 case 'x': 4903 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4904 0); 4905 break; 4906 } 4907 break; 4908 } 4909 ++fmt; 4910 } 4911 } 4912 } 4913 } 4914 4915 /* 4916 * Unload a dlopened object and its dependencies from memory and from 4917 * our data structures. It is assumed that the DAG rooted in the 4918 * object has already been unreferenced, and that the object has a 4919 * reference count of 0. 4920 */ 4921 static void 4922 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4923 { 4924 Obj_Entry marker, *obj, *next; 4925 4926 assert(root->refcount == 0); 4927 4928 /* 4929 * Pass over the DAG removing unreferenced objects from 4930 * appropriate lists. 4931 */ 4932 unlink_object(root); 4933 4934 /* Unmap all objects that are no longer referenced. */ 4935 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4936 next = TAILQ_NEXT(obj, next); 4937 if (obj->marker || obj->refcount != 0) 4938 continue; 4939 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4940 obj->mapsize, 0, obj->path); 4941 dbg("unloading \"%s\"", obj->path); 4942 /* 4943 * Unlink the object now to prevent new references from 4944 * being acquired while the bind lock is dropped in 4945 * recursive dlclose() invocations. 4946 */ 4947 TAILQ_REMOVE(&obj_list, obj, next); 4948 obj_count--; 4949 4950 if (obj->filtees_loaded) { 4951 if (next != NULL) { 4952 init_marker(&marker); 4953 TAILQ_INSERT_BEFORE(next, &marker, next); 4954 unload_filtees(obj, lockstate); 4955 next = TAILQ_NEXT(&marker, next); 4956 TAILQ_REMOVE(&obj_list, &marker, next); 4957 } else 4958 unload_filtees(obj, lockstate); 4959 } 4960 release_object(obj); 4961 } 4962 } 4963 4964 static void 4965 unlink_object(Obj_Entry *root) 4966 { 4967 Objlist_Entry *elm; 4968 4969 if (root->refcount == 0) { 4970 /* Remove the object from the RTLD_GLOBAL list. */ 4971 objlist_remove(&list_global, root); 4972 4973 /* Remove the object from all objects' DAG lists. */ 4974 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4975 objlist_remove(&elm->obj->dldags, root); 4976 if (elm->obj != root) 4977 unlink_object(elm->obj); 4978 } 4979 } 4980 } 4981 4982 static void 4983 ref_dag(Obj_Entry *root) 4984 { 4985 Objlist_Entry *elm; 4986 4987 assert(root->dag_inited); 4988 STAILQ_FOREACH(elm, &root->dagmembers, link) 4989 elm->obj->refcount++; 4990 } 4991 4992 static void 4993 unref_dag(Obj_Entry *root) 4994 { 4995 Objlist_Entry *elm; 4996 4997 assert(root->dag_inited); 4998 STAILQ_FOREACH(elm, &root->dagmembers, link) 4999 elm->obj->refcount--; 5000 } 5001 5002 /* 5003 * Common code for MD __tls_get_addr(). 5004 */ 5005 static void * 5006 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5007 { 5008 Elf_Addr *newdtv, *dtv; 5009 RtldLockState lockstate; 5010 int to_copy; 5011 5012 dtv = *dtvp; 5013 /* Check dtv generation in case new modules have arrived */ 5014 if (dtv[0] != tls_dtv_generation) { 5015 if (!locked) 5016 wlock_acquire(rtld_bind_lock, &lockstate); 5017 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5018 to_copy = dtv[1]; 5019 if (to_copy > tls_max_index) 5020 to_copy = tls_max_index; 5021 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5022 newdtv[0] = tls_dtv_generation; 5023 newdtv[1] = tls_max_index; 5024 free(dtv); 5025 if (!locked) 5026 lock_release(rtld_bind_lock, &lockstate); 5027 dtv = *dtvp = newdtv; 5028 } 5029 5030 /* Dynamically allocate module TLS if necessary */ 5031 if (dtv[index + 1] == 0) { 5032 /* Signal safe, wlock will block out signals. */ 5033 if (!locked) 5034 wlock_acquire(rtld_bind_lock, &lockstate); 5035 if (!dtv[index + 1]) 5036 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5037 if (!locked) 5038 lock_release(rtld_bind_lock, &lockstate); 5039 } 5040 return ((void *)(dtv[index + 1] + offset)); 5041 } 5042 5043 void * 5044 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 5045 { 5046 Elf_Addr *dtv; 5047 5048 dtv = *dtvp; 5049 /* Check dtv generation in case new modules have arrived */ 5050 if (__predict_true(dtv[0] == tls_dtv_generation && 5051 dtv[index + 1] != 0)) 5052 return ((void *)(dtv[index + 1] + offset)); 5053 return (tls_get_addr_slow(dtvp, index, offset, false)); 5054 } 5055 5056 #ifdef TLS_VARIANT_I 5057 5058 /* 5059 * Return pointer to allocated TLS block 5060 */ 5061 static void * 5062 get_tls_block_ptr(void *tcb, size_t tcbsize) 5063 { 5064 size_t extra_size, post_size, pre_size, tls_block_size; 5065 size_t tls_init_align; 5066 5067 tls_init_align = MAX(obj_main->tlsalign, 1); 5068 5069 /* Compute fragments sizes. */ 5070 extra_size = tcbsize - TLS_TCB_SIZE; 5071 post_size = calculate_tls_post_size(tls_init_align); 5072 tls_block_size = tcbsize + post_size; 5073 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5074 5075 return ((char *)tcb - pre_size - extra_size); 5076 } 5077 5078 /* 5079 * Allocate Static TLS using the Variant I method. 5080 * 5081 * For details on the layout, see lib/libc/gen/tls.c. 5082 * 5083 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5084 * it is based on tls_last_offset, and TLS offsets here are really TCB 5085 * offsets, whereas libc's tls_static_space is just the executable's static 5086 * TLS segment. 5087 */ 5088 void * 5089 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5090 { 5091 Obj_Entry *obj; 5092 char *tls_block; 5093 Elf_Addr *dtv, **tcb; 5094 Elf_Addr addr; 5095 Elf_Addr i; 5096 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5097 size_t tls_init_align, tls_init_offset; 5098 5099 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5100 return (oldtcb); 5101 5102 assert(tcbsize >= TLS_TCB_SIZE); 5103 maxalign = MAX(tcbalign, tls_static_max_align); 5104 tls_init_align = MAX(obj_main->tlsalign, 1); 5105 5106 /* Compute fragmets sizes. */ 5107 extra_size = tcbsize - TLS_TCB_SIZE; 5108 post_size = calculate_tls_post_size(tls_init_align); 5109 tls_block_size = tcbsize + post_size; 5110 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5111 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5112 5113 /* Allocate whole TLS block */ 5114 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5115 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5116 5117 if (oldtcb != NULL) { 5118 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5119 tls_static_space); 5120 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5121 5122 /* Adjust the DTV. */ 5123 dtv = tcb[0]; 5124 for (i = 0; i < dtv[1]; i++) { 5125 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5126 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5127 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5128 } 5129 } 5130 } else { 5131 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5132 tcb[0] = dtv; 5133 dtv[0] = tls_dtv_generation; 5134 dtv[1] = tls_max_index; 5135 5136 for (obj = globallist_curr(objs); obj != NULL; 5137 obj = globallist_next(obj)) { 5138 if (obj->tlsoffset == 0) 5139 continue; 5140 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5141 addr = (Elf_Addr)tcb + obj->tlsoffset; 5142 if (tls_init_offset > 0) 5143 memset((void *)addr, 0, tls_init_offset); 5144 if (obj->tlsinitsize > 0) { 5145 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5146 obj->tlsinitsize); 5147 } 5148 if (obj->tlssize > obj->tlsinitsize) { 5149 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5150 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5151 } 5152 dtv[obj->tlsindex + 1] = addr; 5153 } 5154 } 5155 5156 return (tcb); 5157 } 5158 5159 void 5160 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5161 { 5162 Elf_Addr *dtv; 5163 Elf_Addr tlsstart, tlsend; 5164 size_t post_size; 5165 size_t dtvsize, i, tls_init_align; 5166 5167 assert(tcbsize >= TLS_TCB_SIZE); 5168 tls_init_align = MAX(obj_main->tlsalign, 1); 5169 5170 /* Compute fragments sizes. */ 5171 post_size = calculate_tls_post_size(tls_init_align); 5172 5173 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5174 tlsend = (Elf_Addr)tcb + tls_static_space; 5175 5176 dtv = *(Elf_Addr **)tcb; 5177 dtvsize = dtv[1]; 5178 for (i = 0; i < dtvsize; i++) { 5179 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5180 free((void*)dtv[i+2]); 5181 } 5182 } 5183 free(dtv); 5184 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5185 } 5186 5187 #endif /* TLS_VARIANT_I */ 5188 5189 #ifdef TLS_VARIANT_II 5190 5191 /* 5192 * Allocate Static TLS using the Variant II method. 5193 */ 5194 void * 5195 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5196 { 5197 Obj_Entry *obj; 5198 size_t size, ralign; 5199 char *tls; 5200 Elf_Addr *dtv, *olddtv; 5201 Elf_Addr segbase, oldsegbase, addr; 5202 size_t i; 5203 5204 ralign = tcbalign; 5205 if (tls_static_max_align > ralign) 5206 ralign = tls_static_max_align; 5207 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5208 5209 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5210 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5211 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5212 5213 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5214 ((Elf_Addr*)segbase)[0] = segbase; 5215 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5216 5217 dtv[0] = tls_dtv_generation; 5218 dtv[1] = tls_max_index; 5219 5220 if (oldtls) { 5221 /* 5222 * Copy the static TLS block over whole. 5223 */ 5224 oldsegbase = (Elf_Addr) oldtls; 5225 memcpy((void *)(segbase - tls_static_space), 5226 (const void *)(oldsegbase - tls_static_space), 5227 tls_static_space); 5228 5229 /* 5230 * If any dynamic TLS blocks have been created tls_get_addr(), 5231 * move them over. 5232 */ 5233 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5234 for (i = 0; i < olddtv[1]; i++) { 5235 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5236 dtv[i+2] = olddtv[i+2]; 5237 olddtv[i+2] = 0; 5238 } 5239 } 5240 5241 /* 5242 * We assume that this block was the one we created with 5243 * allocate_initial_tls(). 5244 */ 5245 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5246 } else { 5247 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5248 if (obj->marker || obj->tlsoffset == 0) 5249 continue; 5250 addr = segbase - obj->tlsoffset; 5251 memset((void*)(addr + obj->tlsinitsize), 5252 0, obj->tlssize - obj->tlsinitsize); 5253 if (obj->tlsinit) { 5254 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5255 obj->static_tls_copied = true; 5256 } 5257 dtv[obj->tlsindex + 1] = addr; 5258 } 5259 } 5260 5261 return (void*) segbase; 5262 } 5263 5264 void 5265 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5266 { 5267 Elf_Addr* dtv; 5268 size_t size, ralign; 5269 int dtvsize, i; 5270 Elf_Addr tlsstart, tlsend; 5271 5272 /* 5273 * Figure out the size of the initial TLS block so that we can 5274 * find stuff which ___tls_get_addr() allocated dynamically. 5275 */ 5276 ralign = tcbalign; 5277 if (tls_static_max_align > ralign) 5278 ralign = tls_static_max_align; 5279 size = roundup(tls_static_space, ralign); 5280 5281 dtv = ((Elf_Addr**)tls)[1]; 5282 dtvsize = dtv[1]; 5283 tlsend = (Elf_Addr) tls; 5284 tlsstart = tlsend - size; 5285 for (i = 0; i < dtvsize; i++) { 5286 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5287 free_aligned((void *)dtv[i + 2]); 5288 } 5289 } 5290 5291 free_aligned((void *)tlsstart); 5292 free((void*) dtv); 5293 } 5294 5295 #endif /* TLS_VARIANT_II */ 5296 5297 /* 5298 * Allocate TLS block for module with given index. 5299 */ 5300 void * 5301 allocate_module_tls(int index) 5302 { 5303 Obj_Entry *obj; 5304 char *p; 5305 5306 TAILQ_FOREACH(obj, &obj_list, next) { 5307 if (obj->marker) 5308 continue; 5309 if (obj->tlsindex == index) 5310 break; 5311 } 5312 if (obj == NULL) { 5313 _rtld_error("Can't find module with TLS index %d", index); 5314 rtld_die(); 5315 } 5316 5317 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5318 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5319 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5320 return (p); 5321 } 5322 5323 bool 5324 allocate_tls_offset(Obj_Entry *obj) 5325 { 5326 size_t off; 5327 5328 if (obj->tls_done) 5329 return true; 5330 5331 if (obj->tlssize == 0) { 5332 obj->tls_done = true; 5333 return true; 5334 } 5335 5336 if (tls_last_offset == 0) 5337 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5338 obj->tlspoffset); 5339 else 5340 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5341 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5342 5343 obj->tlsoffset = off; 5344 #ifdef TLS_VARIANT_I 5345 off += obj->tlssize; 5346 #endif 5347 5348 /* 5349 * If we have already fixed the size of the static TLS block, we 5350 * must stay within that size. When allocating the static TLS, we 5351 * leave a small amount of space spare to be used for dynamically 5352 * loading modules which use static TLS. 5353 */ 5354 if (tls_static_space != 0) { 5355 if (off > tls_static_space) 5356 return false; 5357 } else if (obj->tlsalign > tls_static_max_align) { 5358 tls_static_max_align = obj->tlsalign; 5359 } 5360 5361 tls_last_offset = off; 5362 tls_last_size = obj->tlssize; 5363 obj->tls_done = true; 5364 5365 return true; 5366 } 5367 5368 void 5369 free_tls_offset(Obj_Entry *obj) 5370 { 5371 5372 /* 5373 * If we were the last thing to allocate out of the static TLS 5374 * block, we give our space back to the 'allocator'. This is a 5375 * simplistic workaround to allow libGL.so.1 to be loaded and 5376 * unloaded multiple times. 5377 */ 5378 size_t off = obj->tlsoffset; 5379 #ifdef TLS_VARIANT_I 5380 off += obj->tlssize; 5381 #endif 5382 if (off == tls_last_offset) { 5383 tls_last_offset -= obj->tlssize; 5384 tls_last_size = 0; 5385 } 5386 } 5387 5388 void * 5389 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5390 { 5391 void *ret; 5392 RtldLockState lockstate; 5393 5394 wlock_acquire(rtld_bind_lock, &lockstate); 5395 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5396 tcbsize, tcbalign); 5397 lock_release(rtld_bind_lock, &lockstate); 5398 return (ret); 5399 } 5400 5401 void 5402 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5403 { 5404 RtldLockState lockstate; 5405 5406 wlock_acquire(rtld_bind_lock, &lockstate); 5407 free_tls(tcb, tcbsize, tcbalign); 5408 lock_release(rtld_bind_lock, &lockstate); 5409 } 5410 5411 static void 5412 object_add_name(Obj_Entry *obj, const char *name) 5413 { 5414 Name_Entry *entry; 5415 size_t len; 5416 5417 len = strlen(name); 5418 entry = malloc(sizeof(Name_Entry) + len); 5419 5420 if (entry != NULL) { 5421 strcpy(entry->name, name); 5422 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5423 } 5424 } 5425 5426 static int 5427 object_match_name(const Obj_Entry *obj, const char *name) 5428 { 5429 Name_Entry *entry; 5430 5431 STAILQ_FOREACH(entry, &obj->names, link) { 5432 if (strcmp(name, entry->name) == 0) 5433 return (1); 5434 } 5435 return (0); 5436 } 5437 5438 static Obj_Entry * 5439 locate_dependency(const Obj_Entry *obj, const char *name) 5440 { 5441 const Objlist_Entry *entry; 5442 const Needed_Entry *needed; 5443 5444 STAILQ_FOREACH(entry, &list_main, link) { 5445 if (object_match_name(entry->obj, name)) 5446 return entry->obj; 5447 } 5448 5449 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5450 if (strcmp(obj->strtab + needed->name, name) == 0 || 5451 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5452 /* 5453 * If there is DT_NEEDED for the name we are looking for, 5454 * we are all set. Note that object might not be found if 5455 * dependency was not loaded yet, so the function can 5456 * return NULL here. This is expected and handled 5457 * properly by the caller. 5458 */ 5459 return (needed->obj); 5460 } 5461 } 5462 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5463 obj->path, name); 5464 rtld_die(); 5465 } 5466 5467 static int 5468 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5469 const Elf_Vernaux *vna) 5470 { 5471 const Elf_Verdef *vd; 5472 const char *vername; 5473 5474 vername = refobj->strtab + vna->vna_name; 5475 vd = depobj->verdef; 5476 if (vd == NULL) { 5477 _rtld_error("%s: version %s required by %s not defined", 5478 depobj->path, vername, refobj->path); 5479 return (-1); 5480 } 5481 for (;;) { 5482 if (vd->vd_version != VER_DEF_CURRENT) { 5483 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5484 depobj->path, vd->vd_version); 5485 return (-1); 5486 } 5487 if (vna->vna_hash == vd->vd_hash) { 5488 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5489 ((const char *)vd + vd->vd_aux); 5490 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5491 return (0); 5492 } 5493 if (vd->vd_next == 0) 5494 break; 5495 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5496 } 5497 if (vna->vna_flags & VER_FLG_WEAK) 5498 return (0); 5499 _rtld_error("%s: version %s required by %s not found", 5500 depobj->path, vername, refobj->path); 5501 return (-1); 5502 } 5503 5504 static int 5505 rtld_verify_object_versions(Obj_Entry *obj) 5506 { 5507 const Elf_Verneed *vn; 5508 const Elf_Verdef *vd; 5509 const Elf_Verdaux *vda; 5510 const Elf_Vernaux *vna; 5511 const Obj_Entry *depobj; 5512 int maxvernum, vernum; 5513 5514 if (obj->ver_checked) 5515 return (0); 5516 obj->ver_checked = true; 5517 5518 maxvernum = 0; 5519 /* 5520 * Walk over defined and required version records and figure out 5521 * max index used by any of them. Do very basic sanity checking 5522 * while there. 5523 */ 5524 vn = obj->verneed; 5525 while (vn != NULL) { 5526 if (vn->vn_version != VER_NEED_CURRENT) { 5527 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5528 obj->path, vn->vn_version); 5529 return (-1); 5530 } 5531 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5532 for (;;) { 5533 vernum = VER_NEED_IDX(vna->vna_other); 5534 if (vernum > maxvernum) 5535 maxvernum = vernum; 5536 if (vna->vna_next == 0) 5537 break; 5538 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5539 } 5540 if (vn->vn_next == 0) 5541 break; 5542 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5543 } 5544 5545 vd = obj->verdef; 5546 while (vd != NULL) { 5547 if (vd->vd_version != VER_DEF_CURRENT) { 5548 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5549 obj->path, vd->vd_version); 5550 return (-1); 5551 } 5552 vernum = VER_DEF_IDX(vd->vd_ndx); 5553 if (vernum > maxvernum) 5554 maxvernum = vernum; 5555 if (vd->vd_next == 0) 5556 break; 5557 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5558 } 5559 5560 if (maxvernum == 0) 5561 return (0); 5562 5563 /* 5564 * Store version information in array indexable by version index. 5565 * Verify that object version requirements are satisfied along the 5566 * way. 5567 */ 5568 obj->vernum = maxvernum + 1; 5569 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5570 5571 vd = obj->verdef; 5572 while (vd != NULL) { 5573 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5574 vernum = VER_DEF_IDX(vd->vd_ndx); 5575 assert(vernum <= maxvernum); 5576 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5577 obj->vertab[vernum].hash = vd->vd_hash; 5578 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5579 obj->vertab[vernum].file = NULL; 5580 obj->vertab[vernum].flags = 0; 5581 } 5582 if (vd->vd_next == 0) 5583 break; 5584 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5585 } 5586 5587 vn = obj->verneed; 5588 while (vn != NULL) { 5589 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5590 if (depobj == NULL) 5591 return (-1); 5592 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5593 for (;;) { 5594 if (check_object_provided_version(obj, depobj, vna)) 5595 return (-1); 5596 vernum = VER_NEED_IDX(vna->vna_other); 5597 assert(vernum <= maxvernum); 5598 obj->vertab[vernum].hash = vna->vna_hash; 5599 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5600 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5601 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5602 VER_INFO_HIDDEN : 0; 5603 if (vna->vna_next == 0) 5604 break; 5605 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5606 } 5607 if (vn->vn_next == 0) 5608 break; 5609 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5610 } 5611 return 0; 5612 } 5613 5614 static int 5615 rtld_verify_versions(const Objlist *objlist) 5616 { 5617 Objlist_Entry *entry; 5618 int rc; 5619 5620 rc = 0; 5621 STAILQ_FOREACH(entry, objlist, link) { 5622 /* 5623 * Skip dummy objects or objects that have their version requirements 5624 * already checked. 5625 */ 5626 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5627 continue; 5628 if (rtld_verify_object_versions(entry->obj) == -1) { 5629 rc = -1; 5630 if (ld_tracing == NULL) 5631 break; 5632 } 5633 } 5634 if (rc == 0 || ld_tracing != NULL) 5635 rc = rtld_verify_object_versions(&obj_rtld); 5636 return rc; 5637 } 5638 5639 const Ver_Entry * 5640 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5641 { 5642 Elf_Versym vernum; 5643 5644 if (obj->vertab) { 5645 vernum = VER_NDX(obj->versyms[symnum]); 5646 if (vernum >= obj->vernum) { 5647 _rtld_error("%s: symbol %s has wrong verneed value %d", 5648 obj->path, obj->strtab + symnum, vernum); 5649 } else if (obj->vertab[vernum].hash != 0) { 5650 return &obj->vertab[vernum]; 5651 } 5652 } 5653 return NULL; 5654 } 5655 5656 int 5657 _rtld_get_stack_prot(void) 5658 { 5659 5660 return (stack_prot); 5661 } 5662 5663 int 5664 _rtld_is_dlopened(void *arg) 5665 { 5666 Obj_Entry *obj; 5667 RtldLockState lockstate; 5668 int res; 5669 5670 rlock_acquire(rtld_bind_lock, &lockstate); 5671 obj = dlcheck(arg); 5672 if (obj == NULL) 5673 obj = obj_from_addr(arg); 5674 if (obj == NULL) { 5675 _rtld_error("No shared object contains address"); 5676 lock_release(rtld_bind_lock, &lockstate); 5677 return (-1); 5678 } 5679 res = obj->dlopened ? 1 : 0; 5680 lock_release(rtld_bind_lock, &lockstate); 5681 return (res); 5682 } 5683 5684 static int 5685 obj_remap_relro(Obj_Entry *obj, int prot) 5686 { 5687 5688 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5689 prot) == -1) { 5690 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5691 obj->path, prot, rtld_strerror(errno)); 5692 return (-1); 5693 } 5694 return (0); 5695 } 5696 5697 static int 5698 obj_disable_relro(Obj_Entry *obj) 5699 { 5700 5701 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5702 } 5703 5704 static int 5705 obj_enforce_relro(Obj_Entry *obj) 5706 { 5707 5708 return (obj_remap_relro(obj, PROT_READ)); 5709 } 5710 5711 static void 5712 map_stacks_exec(RtldLockState *lockstate) 5713 { 5714 void (*thr_map_stacks_exec)(void); 5715 5716 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5717 return; 5718 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5719 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5720 if (thr_map_stacks_exec != NULL) { 5721 stack_prot |= PROT_EXEC; 5722 thr_map_stacks_exec(); 5723 } 5724 } 5725 5726 static void 5727 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5728 { 5729 Objlist_Entry *elm; 5730 Obj_Entry *obj; 5731 void (*distrib)(size_t, void *, size_t, size_t); 5732 5733 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5734 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5735 if (distrib == NULL) 5736 return; 5737 STAILQ_FOREACH(elm, list, link) { 5738 obj = elm->obj; 5739 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5740 continue; 5741 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5742 obj->tlssize); 5743 obj->static_tls_copied = true; 5744 } 5745 } 5746 5747 void 5748 symlook_init(SymLook *dst, const char *name) 5749 { 5750 5751 bzero(dst, sizeof(*dst)); 5752 dst->name = name; 5753 dst->hash = elf_hash(name); 5754 dst->hash_gnu = gnu_hash(name); 5755 } 5756 5757 static void 5758 symlook_init_from_req(SymLook *dst, const SymLook *src) 5759 { 5760 5761 dst->name = src->name; 5762 dst->hash = src->hash; 5763 dst->hash_gnu = src->hash_gnu; 5764 dst->ventry = src->ventry; 5765 dst->flags = src->flags; 5766 dst->defobj_out = NULL; 5767 dst->sym_out = NULL; 5768 dst->lockstate = src->lockstate; 5769 } 5770 5771 static int 5772 open_binary_fd(const char *argv0, bool search_in_path, 5773 const char **binpath_res) 5774 { 5775 char *binpath, *pathenv, *pe, *res1; 5776 const char *res; 5777 int fd; 5778 5779 binpath = NULL; 5780 res = NULL; 5781 if (search_in_path && strchr(argv0, '/') == NULL) { 5782 binpath = xmalloc(PATH_MAX); 5783 pathenv = getenv("PATH"); 5784 if (pathenv == NULL) { 5785 _rtld_error("-p and no PATH environment variable"); 5786 rtld_die(); 5787 } 5788 pathenv = strdup(pathenv); 5789 if (pathenv == NULL) { 5790 _rtld_error("Cannot allocate memory"); 5791 rtld_die(); 5792 } 5793 fd = -1; 5794 errno = ENOENT; 5795 while ((pe = strsep(&pathenv, ":")) != NULL) { 5796 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5797 continue; 5798 if (binpath[0] != '\0' && 5799 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5800 continue; 5801 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5802 continue; 5803 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5804 if (fd != -1 || errno != ENOENT) { 5805 res = binpath; 5806 break; 5807 } 5808 } 5809 free(pathenv); 5810 } else { 5811 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5812 res = argv0; 5813 } 5814 5815 if (fd == -1) { 5816 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5817 rtld_die(); 5818 } 5819 if (res != NULL && res[0] != '/') { 5820 res1 = xmalloc(PATH_MAX); 5821 if (realpath(res, res1) != NULL) { 5822 if (res != argv0) 5823 free(__DECONST(char *, res)); 5824 res = res1; 5825 } else { 5826 free(res1); 5827 } 5828 } 5829 *binpath_res = res; 5830 return (fd); 5831 } 5832 5833 /* 5834 * Parse a set of command-line arguments. 5835 */ 5836 static int 5837 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5838 const char **argv0) 5839 { 5840 const char *arg; 5841 char machine[64]; 5842 size_t sz; 5843 int arglen, fd, i, j, mib[2]; 5844 char opt; 5845 bool seen_b, seen_f; 5846 5847 dbg("Parsing command-line arguments"); 5848 *use_pathp = false; 5849 *fdp = -1; 5850 seen_b = seen_f = false; 5851 5852 for (i = 1; i < argc; i++ ) { 5853 arg = argv[i]; 5854 dbg("argv[%d]: '%s'", i, arg); 5855 5856 /* 5857 * rtld arguments end with an explicit "--" or with the first 5858 * non-prefixed argument. 5859 */ 5860 if (strcmp(arg, "--") == 0) { 5861 i++; 5862 break; 5863 } 5864 if (arg[0] != '-') 5865 break; 5866 5867 /* 5868 * All other arguments are single-character options that can 5869 * be combined, so we need to search through `arg` for them. 5870 */ 5871 arglen = strlen(arg); 5872 for (j = 1; j < arglen; j++) { 5873 opt = arg[j]; 5874 if (opt == 'h') { 5875 print_usage(argv[0]); 5876 _exit(0); 5877 } else if (opt == 'b') { 5878 if (seen_f) { 5879 _rtld_error("Both -b and -f specified"); 5880 rtld_die(); 5881 } 5882 i++; 5883 *argv0 = argv[i]; 5884 seen_b = true; 5885 break; 5886 } else if (opt == 'f') { 5887 if (seen_b) { 5888 _rtld_error("Both -b and -f specified"); 5889 rtld_die(); 5890 } 5891 5892 /* 5893 * -f XX can be used to specify a 5894 * descriptor for the binary named at 5895 * the command line (i.e., the later 5896 * argument will specify the process 5897 * name but the descriptor is what 5898 * will actually be executed). 5899 * 5900 * -f must be the last option in, e.g., -abcf. 5901 */ 5902 if (j != arglen - 1) { 5903 _rtld_error("Invalid options: %s", arg); 5904 rtld_die(); 5905 } 5906 i++; 5907 fd = parse_integer(argv[i]); 5908 if (fd == -1) { 5909 _rtld_error( 5910 "Invalid file descriptor: '%s'", 5911 argv[i]); 5912 rtld_die(); 5913 } 5914 *fdp = fd; 5915 seen_f = true; 5916 break; 5917 } else if (opt == 'p') { 5918 *use_pathp = true; 5919 } else if (opt == 'u') { 5920 trust = false; 5921 } else if (opt == 'v') { 5922 machine[0] = '\0'; 5923 mib[0] = CTL_HW; 5924 mib[1] = HW_MACHINE; 5925 sz = sizeof(machine); 5926 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5927 rtld_printf( 5928 "FreeBSD ld-elf.so.1 %s\n" 5929 "FreeBSD_version %d\n" 5930 "Default lib path %s\n" 5931 "Env prefix %s\n" 5932 "Hint file %s\n" 5933 "libmap file %s\n", 5934 machine, 5935 __FreeBSD_version, ld_standard_library_path, 5936 ld_env_prefix, ld_elf_hints_default, 5937 ld_path_libmap_conf); 5938 _exit(0); 5939 } else { 5940 _rtld_error("Invalid argument: '%s'", arg); 5941 print_usage(argv[0]); 5942 rtld_die(); 5943 } 5944 } 5945 } 5946 5947 if (!seen_b) 5948 *argv0 = argv[i]; 5949 return (i); 5950 } 5951 5952 /* 5953 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5954 */ 5955 static int 5956 parse_integer(const char *str) 5957 { 5958 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5959 const char *orig; 5960 int n; 5961 char c; 5962 5963 orig = str; 5964 n = 0; 5965 for (c = *str; c != '\0'; c = *++str) { 5966 if (c < '0' || c > '9') 5967 return (-1); 5968 5969 n *= RADIX; 5970 n += c - '0'; 5971 } 5972 5973 /* Make sure we actually parsed something. */ 5974 if (str == orig) 5975 return (-1); 5976 return (n); 5977 } 5978 5979 static void 5980 print_usage(const char *argv0) 5981 { 5982 5983 rtld_printf( 5984 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5985 "\n" 5986 "Options:\n" 5987 " -h Display this help message\n" 5988 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5989 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5990 " -p Search in PATH for named binary\n" 5991 " -u Ignore LD_ environment variables\n" 5992 " -v Display identification information\n" 5993 " -- End of RTLD options\n" 5994 " <binary> Name of process to execute\n" 5995 " <args> Arguments to the executed process\n", argv0); 5996 } 5997 5998 /* 5999 * Overrides for libc_pic-provided functions. 6000 */ 6001 6002 int 6003 __getosreldate(void) 6004 { 6005 size_t len; 6006 int oid[2]; 6007 int error, osrel; 6008 6009 if (osreldate != 0) 6010 return (osreldate); 6011 6012 oid[0] = CTL_KERN; 6013 oid[1] = KERN_OSRELDATE; 6014 osrel = 0; 6015 len = sizeof(osrel); 6016 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6017 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6018 osreldate = osrel; 6019 return (osreldate); 6020 } 6021 const char * 6022 rtld_strerror(int errnum) 6023 { 6024 6025 if (errnum < 0 || errnum >= sys_nerr) 6026 return ("Unknown error"); 6027 return (sys_errlist[errnum]); 6028 } 6029 6030 /* malloc */ 6031 void * 6032 malloc(size_t nbytes) 6033 { 6034 6035 return (__crt_malloc(nbytes)); 6036 } 6037 6038 void * 6039 calloc(size_t num, size_t size) 6040 { 6041 6042 return (__crt_calloc(num, size)); 6043 } 6044 6045 void 6046 free(void *cp) 6047 { 6048 6049 __crt_free(cp); 6050 } 6051 6052 void * 6053 realloc(void *cp, size_t nbytes) 6054 { 6055 6056 return (__crt_realloc(cp, nbytes)); 6057 } 6058 6059 extern int _rtld_version__FreeBSD_version __exported; 6060 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6061 6062 extern char _rtld_version_laddr_offset __exported; 6063 char _rtld_version_laddr_offset; 6064 6065 extern char _rtld_version_dlpi_tls_data __exported; 6066 char _rtld_version_dlpi_tls_data; 6067