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(const 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, bool *dir_ignore); 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 const 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 const char *ld_bind_now; /* Environment variable for immediate binding */ 211 static const 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 const char *ld_library_path;/* Environment variable for search path */ 215 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 216 static const char *ld_preload; /* Environment variable for libraries to 217 load first */ 218 static const 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 const char *ld_utrace; /* Use utrace() to log events. */ 223 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 224 static Obj_Entry *obj_main; /* The main program shared object */ 225 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 226 static unsigned int obj_count; /* Number of objects in obj_list */ 227 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 228 229 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 * const n; 371 const 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 const char * 402 ld_get_env_var(int idx) 403 { 404 return (ld_env_vars[idx].val); 405 } 406 407 static const 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; 497 const char *argv0, *binpath, *library_path_rpath; 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, dir_ignore, 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, 593 &argv0, &dir_ignore); 594 explicit_fd = (fd != -1); 595 binpath = NULL; 596 if (!explicit_fd) 597 fd = open_binary_fd(argv0, search_in_path, &binpath); 598 if (fstat(fd, &st) == -1) { 599 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 600 explicit_fd ? "user-provided descriptor" : argv0, 601 rtld_strerror(errno)); 602 rtld_die(); 603 } 604 605 /* 606 * Rough emulation of the permission checks done by 607 * execve(2), only Unix DACs are checked, ACLs are 608 * ignored. Preserve the semantic of disabling owner 609 * to execute if owner x bit is cleared, even if 610 * others x bit is enabled. 611 * mmap(2) does not allow to mmap with PROT_EXEC if 612 * binary' file comes from noexec mount. We cannot 613 * set a text reference on the binary. 614 */ 615 dir_enable = false; 616 if (st.st_uid == geteuid()) { 617 if ((st.st_mode & S_IXUSR) != 0) 618 dir_enable = true; 619 } else if (st.st_gid == getegid()) { 620 if ((st.st_mode & S_IXGRP) != 0) 621 dir_enable = true; 622 } else if ((st.st_mode & S_IXOTH) != 0) { 623 dir_enable = true; 624 } 625 if (!dir_enable && !dir_ignore) { 626 _rtld_error("No execute permission for binary %s", 627 argv0); 628 rtld_die(); 629 } 630 631 /* 632 * For direct exec mode, argv[0] is the interpreter 633 * name, we must remove it and shift arguments left 634 * before invoking binary main. Since stack layout 635 * places environment pointers and aux vectors right 636 * after the terminating NULL, we must shift 637 * environment and aux as well. 638 */ 639 main_argc = argc - rtld_argc; 640 for (i = 0; i <= main_argc; i++) 641 argv[i] = argv[i + rtld_argc]; 642 *argcp -= rtld_argc; 643 environ = env = envp = argv + main_argc + 1; 644 dbg("move env from %p to %p", envp + rtld_argc, envp); 645 do { 646 *envp = *(envp + rtld_argc); 647 } while (*envp++ != NULL); 648 aux = auxp = (Elf_Auxinfo *)envp; 649 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 650 dbg("move aux from %p to %p", auxpf, aux); 651 /* XXXKIB insert place for AT_EXECPATH if not present */ 652 for (;; auxp++, auxpf++) { 653 *auxp = *auxpf; 654 if (auxp->a_type == AT_NULL) 655 break; 656 } 657 /* Since the auxiliary vector has moved, redigest it. */ 658 for (i = 0; i < AT_COUNT; i++) 659 aux_info[i] = NULL; 660 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 661 if (auxp->a_type < AT_COUNT) 662 aux_info[auxp->a_type] = auxp; 663 } 664 665 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 666 if (binpath == NULL) { 667 aux_info[AT_EXECPATH] = NULL; 668 } else { 669 if (aux_info[AT_EXECPATH] == NULL) { 670 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 671 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 672 } 673 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 674 binpath); 675 } 676 } else { 677 _rtld_error("No binary"); 678 rtld_die(); 679 } 680 } 681 } 682 683 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 684 685 /* 686 * If the process is tainted, then we un-set the dangerous environment 687 * variables. The process will be marked as tainted until setuid(2) 688 * is called. If any child process calls setuid(2) we do not want any 689 * future processes to honor the potentially un-safe variables. 690 */ 691 if (!trust) { 692 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 693 lvd = &ld_env_vars[i]; 694 if (lvd->unsecure) 695 lvd->val = NULL; 696 } 697 } 698 699 ld_debug = ld_get_env_var(LD_DEBUG); 700 if (ld_bind_now == NULL) 701 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 702 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 703 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 704 libmap_override = ld_get_env_var(LD_LIBMAP); 705 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 706 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 707 ld_preload = ld_get_env_var(LD_PRELOAD); 708 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 709 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 710 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 711 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 712 if (library_path_rpath != NULL) { 713 if (library_path_rpath[0] == 'y' || 714 library_path_rpath[0] == 'Y' || 715 library_path_rpath[0] == '1') 716 ld_library_path_rpath = true; 717 else 718 ld_library_path_rpath = false; 719 } 720 dangerous_ld_env = libmap_disable || libmap_override != NULL || 721 ld_library_path != NULL || ld_preload != NULL || 722 ld_elf_hints_path != NULL || ld_loadfltr || ld_dynamic_weak; 723 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 724 ld_utrace = ld_get_env_var(LD_UTRACE); 725 726 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 727 ld_elf_hints_path = ld_elf_hints_default; 728 729 if (ld_debug != NULL && *ld_debug != '\0') 730 debug = 1; 731 dbg("%s is initialized, base address = %p", __progname, 732 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 733 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 734 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 735 736 dbg("initializing thread locks"); 737 lockdflt_init(); 738 739 /* 740 * Load the main program, or process its program header if it is 741 * already loaded. 742 */ 743 if (fd != -1) { /* Load the main program. */ 744 dbg("loading main program"); 745 obj_main = map_object(fd, argv0, NULL); 746 close(fd); 747 if (obj_main == NULL) 748 rtld_die(); 749 max_stack_flags = obj_main->stack_flags; 750 } else { /* Main program already loaded. */ 751 dbg("processing main program's program header"); 752 assert(aux_info[AT_PHDR] != NULL); 753 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 754 assert(aux_info[AT_PHNUM] != NULL); 755 phnum = aux_info[AT_PHNUM]->a_un.a_val; 756 assert(aux_info[AT_PHENT] != NULL); 757 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 758 assert(aux_info[AT_ENTRY] != NULL); 759 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 760 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 761 rtld_die(); 762 } 763 764 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 765 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 766 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 767 if (kexecpath[0] == '/') 768 obj_main->path = kexecpath; 769 else if (getcwd(buf, sizeof(buf)) == NULL || 770 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 771 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 772 obj_main->path = xstrdup(argv0); 773 else 774 obj_main->path = xstrdup(buf); 775 } else { 776 dbg("No AT_EXECPATH or direct exec"); 777 obj_main->path = xstrdup(argv0); 778 } 779 dbg("obj_main path %s", obj_main->path); 780 obj_main->mainprog = true; 781 782 if (aux_info[AT_STACKPROT] != NULL && 783 aux_info[AT_STACKPROT]->a_un.a_val != 0) 784 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 785 786 #ifndef COMPAT_32BIT 787 /* 788 * Get the actual dynamic linker pathname from the executable if 789 * possible. (It should always be possible.) That ensures that 790 * gdb will find the right dynamic linker even if a non-standard 791 * one is being used. 792 */ 793 if (obj_main->interp != NULL && 794 strcmp(obj_main->interp, obj_rtld.path) != 0) { 795 free(obj_rtld.path); 796 obj_rtld.path = xstrdup(obj_main->interp); 797 __progname = obj_rtld.path; 798 } 799 #endif 800 801 if (!digest_dynamic(obj_main, 0)) 802 rtld_die(); 803 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 804 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 805 obj_main->dynsymcount); 806 807 linkmap_add(obj_main); 808 linkmap_add(&obj_rtld); 809 810 /* Link the main program into the list of objects. */ 811 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 812 obj_count++; 813 obj_loads++; 814 815 /* Initialize a fake symbol for resolving undefined weak references. */ 816 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 817 sym_zero.st_shndx = SHN_UNDEF; 818 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 819 820 if (!libmap_disable) 821 libmap_disable = (bool)lm_init(libmap_override); 822 823 dbg("loading LD_PRELOAD_FDS libraries"); 824 if (load_preload_objects(ld_preload_fds, true) == -1) 825 rtld_die(); 826 827 dbg("loading LD_PRELOAD libraries"); 828 if (load_preload_objects(ld_preload, false) == -1) 829 rtld_die(); 830 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 831 832 dbg("loading needed objects"); 833 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 834 0) == -1) 835 rtld_die(); 836 837 /* Make a list of all objects loaded at startup. */ 838 last_interposer = obj_main; 839 TAILQ_FOREACH(obj, &obj_list, next) { 840 if (obj->marker) 841 continue; 842 if (obj->z_interpose && obj != obj_main) { 843 objlist_put_after(&list_main, last_interposer, obj); 844 last_interposer = obj; 845 } else { 846 objlist_push_tail(&list_main, obj); 847 } 848 obj->refcount++; 849 } 850 851 dbg("checking for required versions"); 852 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 853 rtld_die(); 854 855 if (ld_tracing) { /* We're done */ 856 trace_loaded_objects(obj_main); 857 exit(0); 858 } 859 860 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 861 dump_relocations(obj_main); 862 exit (0); 863 } 864 865 /* 866 * Processing tls relocations requires having the tls offsets 867 * initialized. Prepare offsets before starting initial 868 * relocation processing. 869 */ 870 dbg("initializing initial thread local storage offsets"); 871 STAILQ_FOREACH(entry, &list_main, link) { 872 /* 873 * Allocate all the initial objects out of the static TLS 874 * block even if they didn't ask for it. 875 */ 876 allocate_tls_offset(entry->obj); 877 } 878 879 if (relocate_objects(obj_main, 880 ld_bind_now != NULL && *ld_bind_now != '\0', 881 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 882 rtld_die(); 883 884 dbg("doing copy relocations"); 885 if (do_copy_relocations(obj_main) == -1) 886 rtld_die(); 887 888 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 889 dump_relocations(obj_main); 890 exit (0); 891 } 892 893 ifunc_init(aux); 894 895 /* 896 * Setup TLS for main thread. This must be done after the 897 * relocations are processed, since tls initialization section 898 * might be the subject for relocations. 899 */ 900 dbg("initializing initial thread local storage"); 901 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 902 903 dbg("initializing key program variables"); 904 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 905 set_program_var("environ", env); 906 set_program_var("__elf_aux_vector", aux); 907 908 /* Make a list of init functions to call. */ 909 objlist_init(&initlist); 910 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 911 preload_tail, &initlist); 912 913 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 914 915 map_stacks_exec(NULL); 916 917 if (!obj_main->crt_no_init) { 918 /* 919 * Make sure we don't call the main program's init and fini 920 * functions for binaries linked with old crt1 which calls 921 * _init itself. 922 */ 923 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 924 obj_main->preinit_array = obj_main->init_array = 925 obj_main->fini_array = (Elf_Addr)NULL; 926 } 927 928 if (direct_exec) { 929 /* Set osrel for direct-execed binary */ 930 mib[0] = CTL_KERN; 931 mib[1] = KERN_PROC; 932 mib[2] = KERN_PROC_OSREL; 933 mib[3] = getpid(); 934 osrel = obj_main->osrel; 935 sz = sizeof(old_osrel); 936 dbg("setting osrel to %d", osrel); 937 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 938 } 939 940 wlock_acquire(rtld_bind_lock, &lockstate); 941 942 dbg("resolving ifuncs"); 943 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 944 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 945 rtld_die(); 946 947 rtld_exit_ptr = rtld_exit; 948 if (obj_main->crt_no_init) 949 preinit_main(); 950 objlist_call_init(&initlist, &lockstate); 951 _r_debug_postinit(&obj_main->linkmap); 952 objlist_clear(&initlist); 953 dbg("loading filtees"); 954 TAILQ_FOREACH(obj, &obj_list, next) { 955 if (obj->marker) 956 continue; 957 if (ld_loadfltr || obj->z_loadfltr) 958 load_filtees(obj, 0, &lockstate); 959 } 960 961 dbg("enforcing main obj relro"); 962 if (obj_enforce_relro(obj_main) == -1) 963 rtld_die(); 964 965 lock_release(rtld_bind_lock, &lockstate); 966 967 dbg("transferring control to program entry point = %p", obj_main->entry); 968 969 /* Return the exit procedure and the program entry point. */ 970 *exit_proc = rtld_exit_ptr; 971 *objp = obj_main; 972 return (func_ptr_type) obj_main->entry; 973 } 974 975 void * 976 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 977 { 978 void *ptr; 979 Elf_Addr target; 980 981 ptr = (void *)make_function_pointer(def, obj); 982 target = call_ifunc_resolver(ptr); 983 return ((void *)target); 984 } 985 986 /* 987 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 988 * Changes to this function should be applied there as well. 989 */ 990 Elf_Addr 991 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 992 { 993 const Elf_Rel *rel; 994 const Elf_Sym *def; 995 const Obj_Entry *defobj; 996 Elf_Addr *where; 997 Elf_Addr target; 998 RtldLockState lockstate; 999 1000 rlock_acquire(rtld_bind_lock, &lockstate); 1001 if (sigsetjmp(lockstate.env, 0) != 0) 1002 lock_upgrade(rtld_bind_lock, &lockstate); 1003 if (obj->pltrel) 1004 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1005 else 1006 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1007 1008 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1009 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1010 NULL, &lockstate); 1011 if (def == NULL) 1012 rtld_die(); 1013 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1014 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1015 else 1016 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1017 1018 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1019 defobj->strtab + def->st_name, 1020 obj->path == NULL ? NULL : basename(obj->path), 1021 (void *)target, 1022 defobj->path == NULL ? NULL : basename(defobj->path)); 1023 1024 /* 1025 * Write the new contents for the jmpslot. Note that depending on 1026 * architecture, the value which we need to return back to the 1027 * lazy binding trampoline may or may not be the target 1028 * address. The value returned from reloc_jmpslot() is the value 1029 * that the trampoline needs. 1030 */ 1031 target = reloc_jmpslot(where, target, defobj, obj, rel); 1032 lock_release(rtld_bind_lock, &lockstate); 1033 return target; 1034 } 1035 1036 /* 1037 * Error reporting function. Use it like printf. If formats the message 1038 * into a buffer, and sets things up so that the next call to dlerror() 1039 * will return the message. 1040 */ 1041 void 1042 _rtld_error(const char *fmt, ...) 1043 { 1044 va_list ap; 1045 1046 va_start(ap, fmt); 1047 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1048 fmt, ap); 1049 va_end(ap); 1050 *lockinfo.dlerror_seen() = 0; 1051 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1052 } 1053 1054 /* 1055 * Return a dynamically-allocated copy of the current error message, if any. 1056 */ 1057 static struct dlerror_save * 1058 errmsg_save(void) 1059 { 1060 struct dlerror_save *res; 1061 1062 res = xmalloc(sizeof(*res)); 1063 res->seen = *lockinfo.dlerror_seen(); 1064 if (res->seen == 0) 1065 res->msg = xstrdup(lockinfo.dlerror_loc()); 1066 return (res); 1067 } 1068 1069 /* 1070 * Restore the current error message from a copy which was previously saved 1071 * by errmsg_save(). The copy is freed. 1072 */ 1073 static void 1074 errmsg_restore(struct dlerror_save *saved_msg) 1075 { 1076 if (saved_msg == NULL || saved_msg->seen == 1) { 1077 *lockinfo.dlerror_seen() = 1; 1078 } else { 1079 *lockinfo.dlerror_seen() = 0; 1080 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1081 lockinfo.dlerror_loc_sz); 1082 free(saved_msg->msg); 1083 } 1084 free(saved_msg); 1085 } 1086 1087 static const char * 1088 basename(const char *name) 1089 { 1090 const char *p = strrchr(name, '/'); 1091 return p != NULL ? p + 1 : name; 1092 } 1093 1094 static struct utsname uts; 1095 1096 static char * 1097 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1098 const char *subst, bool may_free) 1099 { 1100 char *p, *p1, *res, *resp; 1101 int subst_len, kw_len, subst_count, old_len, new_len; 1102 1103 kw_len = strlen(kw); 1104 1105 /* 1106 * First, count the number of the keyword occurrences, to 1107 * preallocate the final string. 1108 */ 1109 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1110 p1 = strstr(p, kw); 1111 if (p1 == NULL) 1112 break; 1113 } 1114 1115 /* 1116 * If the keyword is not found, just return. 1117 * 1118 * Return non-substituted string if resolution failed. We 1119 * cannot do anything more reasonable, the failure mode of the 1120 * caller is unresolved library anyway. 1121 */ 1122 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1123 return (may_free ? real : xstrdup(real)); 1124 if (obj != NULL) 1125 subst = obj->origin_path; 1126 1127 /* 1128 * There is indeed something to substitute. Calculate the 1129 * length of the resulting string, and allocate it. 1130 */ 1131 subst_len = strlen(subst); 1132 old_len = strlen(real); 1133 new_len = old_len + (subst_len - kw_len) * subst_count; 1134 res = xmalloc(new_len + 1); 1135 1136 /* 1137 * Now, execute the substitution loop. 1138 */ 1139 for (p = real, resp = res, *resp = '\0';;) { 1140 p1 = strstr(p, kw); 1141 if (p1 != NULL) { 1142 /* Copy the prefix before keyword. */ 1143 memcpy(resp, p, p1 - p); 1144 resp += p1 - p; 1145 /* Keyword replacement. */ 1146 memcpy(resp, subst, subst_len); 1147 resp += subst_len; 1148 *resp = '\0'; 1149 p = p1 + kw_len; 1150 } else 1151 break; 1152 } 1153 1154 /* Copy to the end of string and finish. */ 1155 strcat(resp, p); 1156 if (may_free) 1157 free(real); 1158 return (res); 1159 } 1160 1161 static char * 1162 origin_subst(Obj_Entry *obj, const char *real) 1163 { 1164 char *res1, *res2, *res3, *res4; 1165 1166 if (obj == NULL || !trust) 1167 return (xstrdup(real)); 1168 if (uts.sysname[0] == '\0') { 1169 if (uname(&uts) != 0) { 1170 _rtld_error("utsname failed: %d", errno); 1171 return (NULL); 1172 } 1173 } 1174 /* __DECONST is safe here since without may_free real is unchanged */ 1175 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1176 false); 1177 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1178 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1179 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1180 return (res4); 1181 } 1182 1183 void 1184 rtld_die(void) 1185 { 1186 const char *msg = dlerror(); 1187 1188 if (msg == NULL) 1189 msg = "Fatal error"; 1190 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1191 rtld_fdputstr(STDERR_FILENO, msg); 1192 rtld_fdputchar(STDERR_FILENO, '\n'); 1193 _exit(1); 1194 } 1195 1196 /* 1197 * Process a shared object's DYNAMIC section, and save the important 1198 * information in its Obj_Entry structure. 1199 */ 1200 static void 1201 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1202 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1203 { 1204 const Elf_Dyn *dynp; 1205 Needed_Entry **needed_tail = &obj->needed; 1206 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1207 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1208 const Elf_Hashelt *hashtab; 1209 const Elf32_Word *hashval; 1210 Elf32_Word bkt, nmaskwords; 1211 int bloom_size32; 1212 int plttype = DT_REL; 1213 1214 *dyn_rpath = NULL; 1215 *dyn_soname = NULL; 1216 *dyn_runpath = NULL; 1217 1218 obj->bind_now = false; 1219 dynp = obj->dynamic; 1220 if (dynp == NULL) 1221 return; 1222 for (; dynp->d_tag != DT_NULL; dynp++) { 1223 switch (dynp->d_tag) { 1224 1225 case DT_REL: 1226 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1227 break; 1228 1229 case DT_RELSZ: 1230 obj->relsize = dynp->d_un.d_val; 1231 break; 1232 1233 case DT_RELENT: 1234 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1235 break; 1236 1237 case DT_JMPREL: 1238 obj->pltrel = (const Elf_Rel *) 1239 (obj->relocbase + dynp->d_un.d_ptr); 1240 break; 1241 1242 case DT_PLTRELSZ: 1243 obj->pltrelsize = dynp->d_un.d_val; 1244 break; 1245 1246 case DT_RELA: 1247 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1248 break; 1249 1250 case DT_RELASZ: 1251 obj->relasize = dynp->d_un.d_val; 1252 break; 1253 1254 case DT_RELAENT: 1255 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1256 break; 1257 1258 case DT_PLTREL: 1259 plttype = dynp->d_un.d_val; 1260 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1261 break; 1262 1263 case DT_SYMTAB: 1264 obj->symtab = (const Elf_Sym *) 1265 (obj->relocbase + dynp->d_un.d_ptr); 1266 break; 1267 1268 case DT_SYMENT: 1269 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1270 break; 1271 1272 case DT_STRTAB: 1273 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1274 break; 1275 1276 case DT_STRSZ: 1277 obj->strsize = dynp->d_un.d_val; 1278 break; 1279 1280 case DT_VERNEED: 1281 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1282 dynp->d_un.d_val); 1283 break; 1284 1285 case DT_VERNEEDNUM: 1286 obj->verneednum = dynp->d_un.d_val; 1287 break; 1288 1289 case DT_VERDEF: 1290 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1291 dynp->d_un.d_val); 1292 break; 1293 1294 case DT_VERDEFNUM: 1295 obj->verdefnum = dynp->d_un.d_val; 1296 break; 1297 1298 case DT_VERSYM: 1299 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1300 dynp->d_un.d_val); 1301 break; 1302 1303 case DT_HASH: 1304 { 1305 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1306 dynp->d_un.d_ptr); 1307 obj->nbuckets = hashtab[0]; 1308 obj->nchains = hashtab[1]; 1309 obj->buckets = hashtab + 2; 1310 obj->chains = obj->buckets + obj->nbuckets; 1311 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1312 obj->buckets != NULL; 1313 } 1314 break; 1315 1316 case DT_GNU_HASH: 1317 { 1318 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1319 dynp->d_un.d_ptr); 1320 obj->nbuckets_gnu = hashtab[0]; 1321 obj->symndx_gnu = hashtab[1]; 1322 nmaskwords = hashtab[2]; 1323 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1324 obj->maskwords_bm_gnu = nmaskwords - 1; 1325 obj->shift2_gnu = hashtab[3]; 1326 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1327 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1328 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1329 obj->symndx_gnu; 1330 /* Number of bitmask words is required to be power of 2 */ 1331 obj->valid_hash_gnu = powerof2(nmaskwords) && 1332 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1333 } 1334 break; 1335 1336 case DT_NEEDED: 1337 if (!obj->rtld) { 1338 Needed_Entry *nep = NEW(Needed_Entry); 1339 nep->name = dynp->d_un.d_val; 1340 nep->obj = NULL; 1341 nep->next = NULL; 1342 1343 *needed_tail = nep; 1344 needed_tail = &nep->next; 1345 } 1346 break; 1347 1348 case DT_FILTER: 1349 if (!obj->rtld) { 1350 Needed_Entry *nep = NEW(Needed_Entry); 1351 nep->name = dynp->d_un.d_val; 1352 nep->obj = NULL; 1353 nep->next = NULL; 1354 1355 *needed_filtees_tail = nep; 1356 needed_filtees_tail = &nep->next; 1357 1358 if (obj->linkmap.l_refname == NULL) 1359 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1360 } 1361 break; 1362 1363 case DT_AUXILIARY: 1364 if (!obj->rtld) { 1365 Needed_Entry *nep = NEW(Needed_Entry); 1366 nep->name = dynp->d_un.d_val; 1367 nep->obj = NULL; 1368 nep->next = NULL; 1369 1370 *needed_aux_filtees_tail = nep; 1371 needed_aux_filtees_tail = &nep->next; 1372 } 1373 break; 1374 1375 case DT_PLTGOT: 1376 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1377 break; 1378 1379 case DT_TEXTREL: 1380 obj->textrel = true; 1381 break; 1382 1383 case DT_SYMBOLIC: 1384 obj->symbolic = true; 1385 break; 1386 1387 case DT_RPATH: 1388 /* 1389 * We have to wait until later to process this, because we 1390 * might not have gotten the address of the string table yet. 1391 */ 1392 *dyn_rpath = dynp; 1393 break; 1394 1395 case DT_SONAME: 1396 *dyn_soname = dynp; 1397 break; 1398 1399 case DT_RUNPATH: 1400 *dyn_runpath = dynp; 1401 break; 1402 1403 case DT_INIT: 1404 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1405 break; 1406 1407 case DT_PREINIT_ARRAY: 1408 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1409 break; 1410 1411 case DT_PREINIT_ARRAYSZ: 1412 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1413 break; 1414 1415 case DT_INIT_ARRAY: 1416 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1417 break; 1418 1419 case DT_INIT_ARRAYSZ: 1420 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1421 break; 1422 1423 case DT_FINI: 1424 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1425 break; 1426 1427 case DT_FINI_ARRAY: 1428 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1429 break; 1430 1431 case DT_FINI_ARRAYSZ: 1432 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1433 break; 1434 1435 /* 1436 * Don't process DT_DEBUG on MIPS as the dynamic section 1437 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1438 */ 1439 1440 #ifndef __mips__ 1441 case DT_DEBUG: 1442 if (!early) 1443 dbg("Filling in DT_DEBUG entry"); 1444 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1445 break; 1446 #endif 1447 1448 case DT_FLAGS: 1449 if (dynp->d_un.d_val & DF_ORIGIN) 1450 obj->z_origin = true; 1451 if (dynp->d_un.d_val & DF_SYMBOLIC) 1452 obj->symbolic = true; 1453 if (dynp->d_un.d_val & DF_TEXTREL) 1454 obj->textrel = true; 1455 if (dynp->d_un.d_val & DF_BIND_NOW) 1456 obj->bind_now = true; 1457 if (dynp->d_un.d_val & DF_STATIC_TLS) 1458 obj->static_tls = true; 1459 break; 1460 #ifdef __mips__ 1461 case DT_MIPS_LOCAL_GOTNO: 1462 obj->local_gotno = dynp->d_un.d_val; 1463 break; 1464 1465 case DT_MIPS_SYMTABNO: 1466 obj->symtabno = dynp->d_un.d_val; 1467 break; 1468 1469 case DT_MIPS_GOTSYM: 1470 obj->gotsym = dynp->d_un.d_val; 1471 break; 1472 1473 case DT_MIPS_RLD_MAP: 1474 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1475 break; 1476 1477 case DT_MIPS_RLD_MAP_REL: 1478 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1479 // section relative to the address of the tag itself. 1480 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1481 (Elf_Addr) &r_debug; 1482 break; 1483 1484 case DT_MIPS_PLTGOT: 1485 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1486 dynp->d_un.d_ptr); 1487 break; 1488 1489 #endif 1490 1491 #ifdef __powerpc__ 1492 #ifdef __powerpc64__ 1493 case DT_PPC64_GLINK: 1494 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1495 break; 1496 #else 1497 case DT_PPC_GOT: 1498 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1499 break; 1500 #endif 1501 #endif 1502 1503 case DT_FLAGS_1: 1504 if (dynp->d_un.d_val & DF_1_NOOPEN) 1505 obj->z_noopen = true; 1506 if (dynp->d_un.d_val & DF_1_ORIGIN) 1507 obj->z_origin = true; 1508 if (dynp->d_un.d_val & DF_1_GLOBAL) 1509 obj->z_global = true; 1510 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1511 obj->bind_now = true; 1512 if (dynp->d_un.d_val & DF_1_NODELETE) 1513 obj->z_nodelete = true; 1514 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1515 obj->z_loadfltr = true; 1516 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1517 obj->z_interpose = true; 1518 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1519 obj->z_nodeflib = true; 1520 if (dynp->d_un.d_val & DF_1_PIE) 1521 obj->z_pie = true; 1522 break; 1523 1524 default: 1525 if (!early) { 1526 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1527 (long)dynp->d_tag); 1528 } 1529 break; 1530 } 1531 } 1532 1533 obj->traced = false; 1534 1535 if (plttype == DT_RELA) { 1536 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1537 obj->pltrel = NULL; 1538 obj->pltrelasize = obj->pltrelsize; 1539 obj->pltrelsize = 0; 1540 } 1541 1542 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1543 if (obj->valid_hash_sysv) 1544 obj->dynsymcount = obj->nchains; 1545 else if (obj->valid_hash_gnu) { 1546 obj->dynsymcount = 0; 1547 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1548 if (obj->buckets_gnu[bkt] == 0) 1549 continue; 1550 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1551 do 1552 obj->dynsymcount++; 1553 while ((*hashval++ & 1u) == 0); 1554 } 1555 obj->dynsymcount += obj->symndx_gnu; 1556 } 1557 1558 if (obj->linkmap.l_refname != NULL) 1559 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1560 linkmap.l_refname; 1561 } 1562 1563 static bool 1564 obj_resolve_origin(Obj_Entry *obj) 1565 { 1566 1567 if (obj->origin_path != NULL) 1568 return (true); 1569 obj->origin_path = xmalloc(PATH_MAX); 1570 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1571 } 1572 1573 static bool 1574 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1575 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1576 { 1577 1578 if (obj->z_origin && !obj_resolve_origin(obj)) 1579 return (false); 1580 1581 if (dyn_runpath != NULL) { 1582 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1583 obj->runpath = origin_subst(obj, obj->runpath); 1584 } else if (dyn_rpath != NULL) { 1585 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1586 obj->rpath = origin_subst(obj, obj->rpath); 1587 } 1588 if (dyn_soname != NULL) 1589 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1590 return (true); 1591 } 1592 1593 static bool 1594 digest_dynamic(Obj_Entry *obj, int early) 1595 { 1596 const Elf_Dyn *dyn_rpath; 1597 const Elf_Dyn *dyn_soname; 1598 const Elf_Dyn *dyn_runpath; 1599 1600 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1601 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1602 } 1603 1604 /* 1605 * Process a shared object's program header. This is used only for the 1606 * main program, when the kernel has already loaded the main program 1607 * into memory before calling the dynamic linker. It creates and 1608 * returns an Obj_Entry structure. 1609 */ 1610 static Obj_Entry * 1611 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1612 { 1613 Obj_Entry *obj; 1614 const Elf_Phdr *phlimit = phdr + phnum; 1615 const Elf_Phdr *ph; 1616 Elf_Addr note_start, note_end; 1617 int nsegs = 0; 1618 1619 obj = obj_new(); 1620 for (ph = phdr; ph < phlimit; ph++) { 1621 if (ph->p_type != PT_PHDR) 1622 continue; 1623 1624 obj->phdr = phdr; 1625 obj->phsize = ph->p_memsz; 1626 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1627 break; 1628 } 1629 1630 obj->stack_flags = PF_X | PF_R | PF_W; 1631 1632 for (ph = phdr; ph < phlimit; ph++) { 1633 switch (ph->p_type) { 1634 1635 case PT_INTERP: 1636 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1637 break; 1638 1639 case PT_LOAD: 1640 if (nsegs == 0) { /* First load segment */ 1641 obj->vaddrbase = trunc_page(ph->p_vaddr); 1642 obj->mapbase = obj->vaddrbase + obj->relocbase; 1643 } else { /* Last load segment */ 1644 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1645 obj->vaddrbase; 1646 } 1647 nsegs++; 1648 break; 1649 1650 case PT_DYNAMIC: 1651 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1652 break; 1653 1654 case PT_TLS: 1655 obj->tlsindex = 1; 1656 obj->tlssize = ph->p_memsz; 1657 obj->tlsalign = ph->p_align; 1658 obj->tlsinitsize = ph->p_filesz; 1659 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1660 obj->tlspoffset = ph->p_offset; 1661 break; 1662 1663 case PT_GNU_STACK: 1664 obj->stack_flags = ph->p_flags; 1665 break; 1666 1667 case PT_GNU_RELRO: 1668 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1669 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1670 trunc_page(ph->p_vaddr); 1671 break; 1672 1673 case PT_NOTE: 1674 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1675 note_end = note_start + ph->p_filesz; 1676 digest_notes(obj, note_start, note_end); 1677 break; 1678 } 1679 } 1680 if (nsegs < 1) { 1681 _rtld_error("%s: too few PT_LOAD segments", path); 1682 return NULL; 1683 } 1684 1685 obj->entry = entry; 1686 return obj; 1687 } 1688 1689 void 1690 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1691 { 1692 const Elf_Note *note; 1693 const char *note_name; 1694 uintptr_t p; 1695 1696 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1697 note = (const Elf_Note *)((const char *)(note + 1) + 1698 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1699 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1700 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1701 note->n_descsz != sizeof(int32_t)) 1702 continue; 1703 if (note->n_type != NT_FREEBSD_ABI_TAG && 1704 note->n_type != NT_FREEBSD_FEATURE_CTL && 1705 note->n_type != NT_FREEBSD_NOINIT_TAG) 1706 continue; 1707 note_name = (const char *)(note + 1); 1708 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1709 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1710 continue; 1711 switch (note->n_type) { 1712 case NT_FREEBSD_ABI_TAG: 1713 /* FreeBSD osrel note */ 1714 p = (uintptr_t)(note + 1); 1715 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1716 obj->osrel = *(const int32_t *)(p); 1717 dbg("note osrel %d", obj->osrel); 1718 break; 1719 case NT_FREEBSD_FEATURE_CTL: 1720 /* FreeBSD ABI feature control note */ 1721 p = (uintptr_t)(note + 1); 1722 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1723 obj->fctl0 = *(const uint32_t *)(p); 1724 dbg("note fctl0 %#x", obj->fctl0); 1725 break; 1726 case NT_FREEBSD_NOINIT_TAG: 1727 /* FreeBSD 'crt does not call init' note */ 1728 obj->crt_no_init = true; 1729 dbg("note crt_no_init"); 1730 break; 1731 } 1732 } 1733 } 1734 1735 static Obj_Entry * 1736 dlcheck(void *handle) 1737 { 1738 Obj_Entry *obj; 1739 1740 TAILQ_FOREACH(obj, &obj_list, next) { 1741 if (obj == (Obj_Entry *) handle) 1742 break; 1743 } 1744 1745 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1746 _rtld_error("Invalid shared object handle %p", handle); 1747 return NULL; 1748 } 1749 return obj; 1750 } 1751 1752 /* 1753 * If the given object is already in the donelist, return true. Otherwise 1754 * add the object to the list and return false. 1755 */ 1756 static bool 1757 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1758 { 1759 unsigned int i; 1760 1761 for (i = 0; i < dlp->num_used; i++) 1762 if (dlp->objs[i] == obj) 1763 return true; 1764 /* 1765 * Our donelist allocation should always be sufficient. But if 1766 * our threads locking isn't working properly, more shared objects 1767 * could have been loaded since we allocated the list. That should 1768 * never happen, but we'll handle it properly just in case it does. 1769 */ 1770 if (dlp->num_used < dlp->num_alloc) 1771 dlp->objs[dlp->num_used++] = obj; 1772 return false; 1773 } 1774 1775 /* 1776 * Hash function for symbol table lookup. Don't even think about changing 1777 * this. It is specified by the System V ABI. 1778 */ 1779 unsigned long 1780 elf_hash(const char *name) 1781 { 1782 const unsigned char *p = (const unsigned char *) name; 1783 unsigned long h = 0; 1784 unsigned long g; 1785 1786 while (*p != '\0') { 1787 h = (h << 4) + *p++; 1788 if ((g = h & 0xf0000000) != 0) 1789 h ^= g >> 24; 1790 h &= ~g; 1791 } 1792 return h; 1793 } 1794 1795 /* 1796 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1797 * unsigned in case it's implemented with a wider type. 1798 */ 1799 static uint32_t 1800 gnu_hash(const char *s) 1801 { 1802 uint32_t h; 1803 unsigned char c; 1804 1805 h = 5381; 1806 for (c = *s; c != '\0'; c = *++s) 1807 h = h * 33 + c; 1808 return (h & 0xffffffff); 1809 } 1810 1811 1812 /* 1813 * Find the library with the given name, and return its full pathname. 1814 * The returned string is dynamically allocated. Generates an error 1815 * message and returns NULL if the library cannot be found. 1816 * 1817 * If the second argument is non-NULL, then it refers to an already- 1818 * loaded shared object, whose library search path will be searched. 1819 * 1820 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1821 * descriptor (which is close-on-exec) will be passed out via the third 1822 * argument. 1823 * 1824 * The search order is: 1825 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1826 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1827 * LD_LIBRARY_PATH 1828 * DT_RUNPATH in the referencing file 1829 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1830 * from list) 1831 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1832 * 1833 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1834 */ 1835 static char * 1836 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1837 { 1838 char *pathname, *refobj_path; 1839 const char *name; 1840 bool nodeflib, objgiven; 1841 1842 objgiven = refobj != NULL; 1843 1844 if (libmap_disable || !objgiven || 1845 (name = lm_find(refobj->path, xname)) == NULL) 1846 name = xname; 1847 1848 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1849 if (name[0] != '/' && !trust) { 1850 _rtld_error("Absolute pathname required " 1851 "for shared object \"%s\"", name); 1852 return (NULL); 1853 } 1854 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1855 __DECONST(char *, name))); 1856 } 1857 1858 dbg(" Searching for \"%s\"", name); 1859 refobj_path = objgiven ? refobj->path : NULL; 1860 1861 /* 1862 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1863 * back to pre-conforming behaviour if user requested so with 1864 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1865 * nodeflib. 1866 */ 1867 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1868 pathname = search_library_path(name, ld_library_path, 1869 refobj_path, fdp); 1870 if (pathname != NULL) 1871 return (pathname); 1872 if (refobj != NULL) { 1873 pathname = search_library_path(name, refobj->rpath, 1874 refobj_path, fdp); 1875 if (pathname != NULL) 1876 return (pathname); 1877 } 1878 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1879 if (pathname != NULL) 1880 return (pathname); 1881 pathname = search_library_path(name, gethints(false), 1882 refobj_path, fdp); 1883 if (pathname != NULL) 1884 return (pathname); 1885 pathname = search_library_path(name, ld_standard_library_path, 1886 refobj_path, fdp); 1887 if (pathname != NULL) 1888 return (pathname); 1889 } else { 1890 nodeflib = objgiven ? refobj->z_nodeflib : false; 1891 if (objgiven) { 1892 pathname = search_library_path(name, refobj->rpath, 1893 refobj->path, fdp); 1894 if (pathname != NULL) 1895 return (pathname); 1896 } 1897 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1898 pathname = search_library_path(name, obj_main->rpath, 1899 refobj_path, fdp); 1900 if (pathname != NULL) 1901 return (pathname); 1902 } 1903 pathname = search_library_path(name, ld_library_path, 1904 refobj_path, fdp); 1905 if (pathname != NULL) 1906 return (pathname); 1907 if (objgiven) { 1908 pathname = search_library_path(name, refobj->runpath, 1909 refobj_path, fdp); 1910 if (pathname != NULL) 1911 return (pathname); 1912 } 1913 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1914 if (pathname != NULL) 1915 return (pathname); 1916 pathname = search_library_path(name, gethints(nodeflib), 1917 refobj_path, fdp); 1918 if (pathname != NULL) 1919 return (pathname); 1920 if (objgiven && !nodeflib) { 1921 pathname = search_library_path(name, 1922 ld_standard_library_path, refobj_path, fdp); 1923 if (pathname != NULL) 1924 return (pathname); 1925 } 1926 } 1927 1928 if (objgiven && refobj->path != NULL) { 1929 _rtld_error("Shared object \"%s\" not found, " 1930 "required by \"%s\"", name, basename(refobj->path)); 1931 } else { 1932 _rtld_error("Shared object \"%s\" not found", name); 1933 } 1934 return (NULL); 1935 } 1936 1937 /* 1938 * Given a symbol number in a referencing object, find the corresponding 1939 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1940 * no definition was found. Returns a pointer to the Obj_Entry of the 1941 * defining object via the reference parameter DEFOBJ_OUT. 1942 */ 1943 const Elf_Sym * 1944 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1945 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1946 RtldLockState *lockstate) 1947 { 1948 const Elf_Sym *ref; 1949 const Elf_Sym *def; 1950 const Obj_Entry *defobj; 1951 const Ver_Entry *ve; 1952 SymLook req; 1953 const char *name; 1954 int res; 1955 1956 /* 1957 * If we have already found this symbol, get the information from 1958 * the cache. 1959 */ 1960 if (symnum >= refobj->dynsymcount) 1961 return NULL; /* Bad object */ 1962 if (cache != NULL && cache[symnum].sym != NULL) { 1963 *defobj_out = cache[symnum].obj; 1964 return cache[symnum].sym; 1965 } 1966 1967 ref = refobj->symtab + symnum; 1968 name = refobj->strtab + ref->st_name; 1969 def = NULL; 1970 defobj = NULL; 1971 ve = NULL; 1972 1973 /* 1974 * We don't have to do a full scale lookup if the symbol is local. 1975 * We know it will bind to the instance in this load module; to 1976 * which we already have a pointer (ie ref). By not doing a lookup, 1977 * we not only improve performance, but it also avoids unresolvable 1978 * symbols when local symbols are not in the hash table. This has 1979 * been seen with the ia64 toolchain. 1980 */ 1981 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1982 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1983 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1984 symnum); 1985 } 1986 symlook_init(&req, name); 1987 req.flags = flags; 1988 ve = req.ventry = fetch_ventry(refobj, symnum); 1989 req.lockstate = lockstate; 1990 res = symlook_default(&req, refobj); 1991 if (res == 0) { 1992 def = req.sym_out; 1993 defobj = req.defobj_out; 1994 } 1995 } else { 1996 def = ref; 1997 defobj = refobj; 1998 } 1999 2000 /* 2001 * If we found no definition and the reference is weak, treat the 2002 * symbol as having the value zero. 2003 */ 2004 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2005 def = &sym_zero; 2006 defobj = obj_main; 2007 } 2008 2009 if (def != NULL) { 2010 *defobj_out = defobj; 2011 /* Record the information in the cache to avoid subsequent lookups. */ 2012 if (cache != NULL) { 2013 cache[symnum].sym = def; 2014 cache[symnum].obj = defobj; 2015 } 2016 } else { 2017 if (refobj != &obj_rtld) 2018 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2019 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2020 } 2021 return def; 2022 } 2023 2024 /* 2025 * Return the search path from the ldconfig hints file, reading it if 2026 * necessary. If nostdlib is true, then the default search paths are 2027 * not added to result. 2028 * 2029 * Returns NULL if there are problems with the hints file, 2030 * or if the search path there is empty. 2031 */ 2032 static const char * 2033 gethints(bool nostdlib) 2034 { 2035 static char *filtered_path; 2036 static const char *hints; 2037 static struct elfhints_hdr hdr; 2038 struct fill_search_info_args sargs, hargs; 2039 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2040 struct dl_serpath *SLPpath, *hintpath; 2041 char *p; 2042 struct stat hint_stat; 2043 unsigned int SLPndx, hintndx, fndx, fcount; 2044 int fd; 2045 size_t flen; 2046 uint32_t dl; 2047 bool skip; 2048 2049 /* First call, read the hints file */ 2050 if (hints == NULL) { 2051 /* Keep from trying again in case the hints file is bad. */ 2052 hints = ""; 2053 2054 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2055 return (NULL); 2056 2057 /* 2058 * Check of hdr.dirlistlen value against type limit 2059 * intends to pacify static analyzers. Further 2060 * paranoia leads to checks that dirlist is fully 2061 * contained in the file range. 2062 */ 2063 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2064 hdr.magic != ELFHINTS_MAGIC || 2065 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2066 fstat(fd, &hint_stat) == -1) { 2067 cleanup1: 2068 close(fd); 2069 hdr.dirlistlen = 0; 2070 return (NULL); 2071 } 2072 dl = hdr.strtab; 2073 if (dl + hdr.dirlist < dl) 2074 goto cleanup1; 2075 dl += hdr.dirlist; 2076 if (dl + hdr.dirlistlen < dl) 2077 goto cleanup1; 2078 dl += hdr.dirlistlen; 2079 if (dl > hint_stat.st_size) 2080 goto cleanup1; 2081 p = xmalloc(hdr.dirlistlen + 1); 2082 if (pread(fd, p, hdr.dirlistlen + 1, 2083 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2084 p[hdr.dirlistlen] != '\0') { 2085 free(p); 2086 goto cleanup1; 2087 } 2088 hints = p; 2089 close(fd); 2090 } 2091 2092 /* 2093 * If caller agreed to receive list which includes the default 2094 * paths, we are done. Otherwise, if we still did not 2095 * calculated filtered result, do it now. 2096 */ 2097 if (!nostdlib) 2098 return (hints[0] != '\0' ? hints : NULL); 2099 if (filtered_path != NULL) 2100 goto filt_ret; 2101 2102 /* 2103 * Obtain the list of all configured search paths, and the 2104 * list of the default paths. 2105 * 2106 * First estimate the size of the results. 2107 */ 2108 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2109 smeta.dls_cnt = 0; 2110 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2111 hmeta.dls_cnt = 0; 2112 2113 sargs.request = RTLD_DI_SERINFOSIZE; 2114 sargs.serinfo = &smeta; 2115 hargs.request = RTLD_DI_SERINFOSIZE; 2116 hargs.serinfo = &hmeta; 2117 2118 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2119 &sargs); 2120 path_enumerate(hints, fill_search_info, NULL, &hargs); 2121 2122 SLPinfo = xmalloc(smeta.dls_size); 2123 hintinfo = xmalloc(hmeta.dls_size); 2124 2125 /* 2126 * Next fetch both sets of paths. 2127 */ 2128 sargs.request = RTLD_DI_SERINFO; 2129 sargs.serinfo = SLPinfo; 2130 sargs.serpath = &SLPinfo->dls_serpath[0]; 2131 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2132 2133 hargs.request = RTLD_DI_SERINFO; 2134 hargs.serinfo = hintinfo; 2135 hargs.serpath = &hintinfo->dls_serpath[0]; 2136 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2137 2138 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2139 &sargs); 2140 path_enumerate(hints, fill_search_info, NULL, &hargs); 2141 2142 /* 2143 * Now calculate the difference between two sets, by excluding 2144 * standard paths from the full set. 2145 */ 2146 fndx = 0; 2147 fcount = 0; 2148 filtered_path = xmalloc(hdr.dirlistlen + 1); 2149 hintpath = &hintinfo->dls_serpath[0]; 2150 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2151 skip = false; 2152 SLPpath = &SLPinfo->dls_serpath[0]; 2153 /* 2154 * Check each standard path against current. 2155 */ 2156 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2157 /* matched, skip the path */ 2158 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2159 skip = true; 2160 break; 2161 } 2162 } 2163 if (skip) 2164 continue; 2165 /* 2166 * Not matched against any standard path, add the path 2167 * to result. Separate consequtive paths with ':'. 2168 */ 2169 if (fcount > 0) { 2170 filtered_path[fndx] = ':'; 2171 fndx++; 2172 } 2173 fcount++; 2174 flen = strlen(hintpath->dls_name); 2175 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2176 fndx += flen; 2177 } 2178 filtered_path[fndx] = '\0'; 2179 2180 free(SLPinfo); 2181 free(hintinfo); 2182 2183 filt_ret: 2184 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2185 } 2186 2187 static void 2188 init_dag(Obj_Entry *root) 2189 { 2190 const Needed_Entry *needed; 2191 const Objlist_Entry *elm; 2192 DoneList donelist; 2193 2194 if (root->dag_inited) 2195 return; 2196 donelist_init(&donelist); 2197 2198 /* Root object belongs to own DAG. */ 2199 objlist_push_tail(&root->dldags, root); 2200 objlist_push_tail(&root->dagmembers, root); 2201 donelist_check(&donelist, root); 2202 2203 /* 2204 * Add dependencies of root object to DAG in breadth order 2205 * by exploiting the fact that each new object get added 2206 * to the tail of the dagmembers list. 2207 */ 2208 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2209 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2210 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2211 continue; 2212 objlist_push_tail(&needed->obj->dldags, root); 2213 objlist_push_tail(&root->dagmembers, needed->obj); 2214 } 2215 } 2216 root->dag_inited = true; 2217 } 2218 2219 static void 2220 init_marker(Obj_Entry *marker) 2221 { 2222 2223 bzero(marker, sizeof(*marker)); 2224 marker->marker = true; 2225 } 2226 2227 Obj_Entry * 2228 globallist_curr(const Obj_Entry *obj) 2229 { 2230 2231 for (;;) { 2232 if (obj == NULL) 2233 return (NULL); 2234 if (!obj->marker) 2235 return (__DECONST(Obj_Entry *, obj)); 2236 obj = TAILQ_PREV(obj, obj_entry_q, next); 2237 } 2238 } 2239 2240 Obj_Entry * 2241 globallist_next(const Obj_Entry *obj) 2242 { 2243 2244 for (;;) { 2245 obj = TAILQ_NEXT(obj, next); 2246 if (obj == NULL) 2247 return (NULL); 2248 if (!obj->marker) 2249 return (__DECONST(Obj_Entry *, obj)); 2250 } 2251 } 2252 2253 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2254 static void 2255 hold_object(Obj_Entry *obj) 2256 { 2257 2258 obj->holdcount++; 2259 } 2260 2261 static void 2262 unhold_object(Obj_Entry *obj) 2263 { 2264 2265 assert(obj->holdcount > 0); 2266 if (--obj->holdcount == 0 && obj->unholdfree) 2267 release_object(obj); 2268 } 2269 2270 static void 2271 process_z(Obj_Entry *root) 2272 { 2273 const Objlist_Entry *elm; 2274 Obj_Entry *obj; 2275 2276 /* 2277 * Walk over object DAG and process every dependent object 2278 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2279 * to grow their own DAG. 2280 * 2281 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2282 * symlook_global() to work. 2283 * 2284 * For DF_1_NODELETE, the DAG should have its reference upped. 2285 */ 2286 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2287 obj = elm->obj; 2288 if (obj == NULL) 2289 continue; 2290 if (obj->z_nodelete && !obj->ref_nodel) { 2291 dbg("obj %s -z nodelete", obj->path); 2292 init_dag(obj); 2293 ref_dag(obj); 2294 obj->ref_nodel = true; 2295 } 2296 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2297 dbg("obj %s -z global", obj->path); 2298 objlist_push_tail(&list_global, obj); 2299 init_dag(obj); 2300 } 2301 } 2302 } 2303 2304 static void 2305 parse_rtld_phdr(Obj_Entry *obj) 2306 { 2307 const Elf_Phdr *ph; 2308 Elf_Addr note_start, note_end; 2309 2310 obj->stack_flags = PF_X | PF_R | PF_W; 2311 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2312 obj->phsize; ph++) { 2313 switch (ph->p_type) { 2314 case PT_GNU_STACK: 2315 obj->stack_flags = ph->p_flags; 2316 break; 2317 case PT_GNU_RELRO: 2318 obj->relro_page = obj->relocbase + 2319 trunc_page(ph->p_vaddr); 2320 obj->relro_size = round_page(ph->p_memsz); 2321 break; 2322 case PT_NOTE: 2323 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2324 note_end = note_start + ph->p_filesz; 2325 digest_notes(obj, note_start, note_end); 2326 break; 2327 } 2328 } 2329 } 2330 2331 /* 2332 * Initialize the dynamic linker. The argument is the address at which 2333 * the dynamic linker has been mapped into memory. The primary task of 2334 * this function is to relocate the dynamic linker. 2335 */ 2336 static void 2337 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2338 { 2339 Obj_Entry objtmp; /* Temporary rtld object */ 2340 const Elf_Ehdr *ehdr; 2341 const Elf_Dyn *dyn_rpath; 2342 const Elf_Dyn *dyn_soname; 2343 const Elf_Dyn *dyn_runpath; 2344 2345 #ifdef RTLD_INIT_PAGESIZES_EARLY 2346 /* The page size is required by the dynamic memory allocator. */ 2347 init_pagesizes(aux_info); 2348 #endif 2349 2350 /* 2351 * Conjure up an Obj_Entry structure for the dynamic linker. 2352 * 2353 * The "path" member can't be initialized yet because string constants 2354 * cannot yet be accessed. Below we will set it correctly. 2355 */ 2356 memset(&objtmp, 0, sizeof(objtmp)); 2357 objtmp.path = NULL; 2358 objtmp.rtld = true; 2359 objtmp.mapbase = mapbase; 2360 #ifdef PIC 2361 objtmp.relocbase = mapbase; 2362 #endif 2363 2364 objtmp.dynamic = rtld_dynamic(&objtmp); 2365 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2366 assert(objtmp.needed == NULL); 2367 #if !defined(__mips__) 2368 /* MIPS has a bogus DT_TEXTREL. */ 2369 assert(!objtmp.textrel); 2370 #endif 2371 /* 2372 * Temporarily put the dynamic linker entry into the object list, so 2373 * that symbols can be found. 2374 */ 2375 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2376 2377 ehdr = (Elf_Ehdr *)mapbase; 2378 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2379 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2380 2381 /* Initialize the object list. */ 2382 TAILQ_INIT(&obj_list); 2383 2384 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2385 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2386 2387 #ifndef RTLD_INIT_PAGESIZES_EARLY 2388 /* The page size is required by the dynamic memory allocator. */ 2389 init_pagesizes(aux_info); 2390 #endif 2391 2392 if (aux_info[AT_OSRELDATE] != NULL) 2393 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2394 2395 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2396 2397 /* Replace the path with a dynamically allocated copy. */ 2398 obj_rtld.path = xstrdup(ld_path_rtld); 2399 2400 parse_rtld_phdr(&obj_rtld); 2401 if (obj_enforce_relro(&obj_rtld) == -1) 2402 rtld_die(); 2403 2404 r_debug.r_version = R_DEBUG_VERSION; 2405 r_debug.r_brk = r_debug_state; 2406 r_debug.r_state = RT_CONSISTENT; 2407 r_debug.r_ldbase = obj_rtld.relocbase; 2408 } 2409 2410 /* 2411 * Retrieve the array of supported page sizes. The kernel provides the page 2412 * sizes in increasing order. 2413 */ 2414 static void 2415 init_pagesizes(Elf_Auxinfo **aux_info) 2416 { 2417 static size_t psa[MAXPAGESIZES]; 2418 int mib[2]; 2419 size_t len, size; 2420 2421 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2422 NULL) { 2423 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2424 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2425 } else { 2426 len = 2; 2427 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2428 size = sizeof(psa); 2429 else { 2430 /* As a fallback, retrieve the base page size. */ 2431 size = sizeof(psa[0]); 2432 if (aux_info[AT_PAGESZ] != NULL) { 2433 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2434 goto psa_filled; 2435 } else { 2436 mib[0] = CTL_HW; 2437 mib[1] = HW_PAGESIZE; 2438 len = 2; 2439 } 2440 } 2441 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2442 _rtld_error("sysctl for hw.pagesize(s) failed"); 2443 rtld_die(); 2444 } 2445 psa_filled: 2446 pagesizes = psa; 2447 } 2448 npagesizes = size / sizeof(pagesizes[0]); 2449 /* Discard any invalid entries at the end of the array. */ 2450 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2451 npagesizes--; 2452 } 2453 2454 /* 2455 * Add the init functions from a needed object list (and its recursive 2456 * needed objects) to "list". This is not used directly; it is a helper 2457 * function for initlist_add_objects(). The write lock must be held 2458 * when this function is called. 2459 */ 2460 static void 2461 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2462 { 2463 /* Recursively process the successor needed objects. */ 2464 if (needed->next != NULL) 2465 initlist_add_neededs(needed->next, list); 2466 2467 /* Process the current needed object. */ 2468 if (needed->obj != NULL) 2469 initlist_add_objects(needed->obj, needed->obj, list); 2470 } 2471 2472 /* 2473 * Scan all of the DAGs rooted in the range of objects from "obj" to 2474 * "tail" and add their init functions to "list". This recurses over 2475 * the DAGs and ensure the proper init ordering such that each object's 2476 * needed libraries are initialized before the object itself. At the 2477 * same time, this function adds the objects to the global finalization 2478 * list "list_fini" in the opposite order. The write lock must be 2479 * held when this function is called. 2480 */ 2481 static void 2482 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2483 { 2484 Obj_Entry *nobj; 2485 2486 if (obj->init_scanned || obj->init_done) 2487 return; 2488 obj->init_scanned = true; 2489 2490 /* Recursively process the successor objects. */ 2491 nobj = globallist_next(obj); 2492 if (nobj != NULL && obj != tail) 2493 initlist_add_objects(nobj, tail, list); 2494 2495 /* Recursively process the needed objects. */ 2496 if (obj->needed != NULL) 2497 initlist_add_neededs(obj->needed, list); 2498 if (obj->needed_filtees != NULL) 2499 initlist_add_neededs(obj->needed_filtees, list); 2500 if (obj->needed_aux_filtees != NULL) 2501 initlist_add_neededs(obj->needed_aux_filtees, list); 2502 2503 /* Add the object to the init list. */ 2504 objlist_push_tail(list, obj); 2505 2506 /* Add the object to the global fini list in the reverse order. */ 2507 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2508 && !obj->on_fini_list) { 2509 objlist_push_head(&list_fini, obj); 2510 obj->on_fini_list = true; 2511 } 2512 } 2513 2514 #ifndef FPTR_TARGET 2515 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2516 #endif 2517 2518 static void 2519 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2520 { 2521 Needed_Entry *needed, *needed1; 2522 2523 for (needed = n; needed != NULL; needed = needed->next) { 2524 if (needed->obj != NULL) { 2525 dlclose_locked(needed->obj, lockstate); 2526 needed->obj = NULL; 2527 } 2528 } 2529 for (needed = n; needed != NULL; needed = needed1) { 2530 needed1 = needed->next; 2531 free(needed); 2532 } 2533 } 2534 2535 static void 2536 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2537 { 2538 2539 free_needed_filtees(obj->needed_filtees, lockstate); 2540 obj->needed_filtees = NULL; 2541 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2542 obj->needed_aux_filtees = NULL; 2543 obj->filtees_loaded = false; 2544 } 2545 2546 static void 2547 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2548 RtldLockState *lockstate) 2549 { 2550 2551 for (; needed != NULL; needed = needed->next) { 2552 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2553 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2554 RTLD_LOCAL, lockstate); 2555 } 2556 } 2557 2558 static void 2559 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2560 { 2561 2562 lock_restart_for_upgrade(lockstate); 2563 if (!obj->filtees_loaded) { 2564 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2565 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2566 obj->filtees_loaded = true; 2567 } 2568 } 2569 2570 static int 2571 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2572 { 2573 Obj_Entry *obj1; 2574 2575 for (; needed != NULL; needed = needed->next) { 2576 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2577 flags & ~RTLD_LO_NOLOAD); 2578 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2579 return (-1); 2580 } 2581 return (0); 2582 } 2583 2584 /* 2585 * Given a shared object, traverse its list of needed objects, and load 2586 * each of them. Returns 0 on success. Generates an error message and 2587 * returns -1 on failure. 2588 */ 2589 static int 2590 load_needed_objects(Obj_Entry *first, int flags) 2591 { 2592 Obj_Entry *obj; 2593 2594 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2595 if (obj->marker) 2596 continue; 2597 if (process_needed(obj, obj->needed, flags) == -1) 2598 return (-1); 2599 } 2600 return (0); 2601 } 2602 2603 static int 2604 load_preload_objects(const char *penv, bool isfd) 2605 { 2606 Obj_Entry *obj; 2607 const char *name; 2608 size_t len; 2609 char savech, *p, *psave; 2610 int fd; 2611 static const char delim[] = " \t:;"; 2612 2613 if (penv == NULL) 2614 return (0); 2615 2616 p = psave = xstrdup(penv); 2617 p += strspn(p, delim); 2618 while (*p != '\0') { 2619 len = strcspn(p, delim); 2620 2621 savech = p[len]; 2622 p[len] = '\0'; 2623 if (isfd) { 2624 name = NULL; 2625 fd = parse_integer(p); 2626 if (fd == -1) { 2627 free(psave); 2628 return (-1); 2629 } 2630 } else { 2631 name = p; 2632 fd = -1; 2633 } 2634 2635 obj = load_object(name, fd, NULL, 0); 2636 if (obj == NULL) { 2637 free(psave); 2638 return (-1); /* XXX - cleanup */ 2639 } 2640 obj->z_interpose = true; 2641 p[len] = savech; 2642 p += len; 2643 p += strspn(p, delim); 2644 } 2645 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2646 2647 free(psave); 2648 return (0); 2649 } 2650 2651 static const char * 2652 printable_path(const char *path) 2653 { 2654 2655 return (path == NULL ? "<unknown>" : path); 2656 } 2657 2658 /* 2659 * Load a shared object into memory, if it is not already loaded. The 2660 * object may be specified by name or by user-supplied file descriptor 2661 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2662 * duplicate is. 2663 * 2664 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2665 * on failure. 2666 */ 2667 static Obj_Entry * 2668 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2669 { 2670 Obj_Entry *obj; 2671 int fd; 2672 struct stat sb; 2673 char *path; 2674 2675 fd = -1; 2676 if (name != NULL) { 2677 TAILQ_FOREACH(obj, &obj_list, next) { 2678 if (obj->marker || obj->doomed) 2679 continue; 2680 if (object_match_name(obj, name)) 2681 return (obj); 2682 } 2683 2684 path = find_library(name, refobj, &fd); 2685 if (path == NULL) 2686 return (NULL); 2687 } else 2688 path = NULL; 2689 2690 if (fd >= 0) { 2691 /* 2692 * search_library_pathfds() opens a fresh file descriptor for the 2693 * library, so there is no need to dup(). 2694 */ 2695 } else if (fd_u == -1) { 2696 /* 2697 * If we didn't find a match by pathname, or the name is not 2698 * supplied, open the file and check again by device and inode. 2699 * This avoids false mismatches caused by multiple links or ".." 2700 * in pathnames. 2701 * 2702 * To avoid a race, we open the file and use fstat() rather than 2703 * using stat(). 2704 */ 2705 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2706 _rtld_error("Cannot open \"%s\"", path); 2707 free(path); 2708 return (NULL); 2709 } 2710 } else { 2711 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2712 if (fd == -1) { 2713 _rtld_error("Cannot dup fd"); 2714 free(path); 2715 return (NULL); 2716 } 2717 } 2718 if (fstat(fd, &sb) == -1) { 2719 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2720 close(fd); 2721 free(path); 2722 return NULL; 2723 } 2724 TAILQ_FOREACH(obj, &obj_list, next) { 2725 if (obj->marker || obj->doomed) 2726 continue; 2727 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2728 break; 2729 } 2730 if (obj != NULL && name != NULL) { 2731 object_add_name(obj, name); 2732 free(path); 2733 close(fd); 2734 return obj; 2735 } 2736 if (flags & RTLD_LO_NOLOAD) { 2737 free(path); 2738 close(fd); 2739 return (NULL); 2740 } 2741 2742 /* First use of this object, so we must map it in */ 2743 obj = do_load_object(fd, name, path, &sb, flags); 2744 if (obj == NULL) 2745 free(path); 2746 close(fd); 2747 2748 return obj; 2749 } 2750 2751 static Obj_Entry * 2752 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2753 int flags) 2754 { 2755 Obj_Entry *obj; 2756 struct statfs fs; 2757 2758 /* 2759 * but first, make sure that environment variables haven't been 2760 * used to circumvent the noexec flag on a filesystem. 2761 */ 2762 if (dangerous_ld_env) { 2763 if (fstatfs(fd, &fs) != 0) { 2764 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2765 return NULL; 2766 } 2767 if (fs.f_flags & MNT_NOEXEC) { 2768 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2769 return NULL; 2770 } 2771 } 2772 dbg("loading \"%s\"", printable_path(path)); 2773 obj = map_object(fd, printable_path(path), sbp); 2774 if (obj == NULL) 2775 return NULL; 2776 2777 /* 2778 * If DT_SONAME is present in the object, digest_dynamic2 already 2779 * added it to the object names. 2780 */ 2781 if (name != NULL) 2782 object_add_name(obj, name); 2783 obj->path = path; 2784 if (!digest_dynamic(obj, 0)) 2785 goto errp; 2786 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2787 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2788 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2789 dbg("refusing to load PIE executable \"%s\"", obj->path); 2790 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2791 goto errp; 2792 } 2793 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2794 RTLD_LO_DLOPEN) { 2795 dbg("refusing to load non-loadable \"%s\"", obj->path); 2796 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2797 goto errp; 2798 } 2799 2800 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2801 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2802 obj_count++; 2803 obj_loads++; 2804 linkmap_add(obj); /* for GDB & dlinfo() */ 2805 max_stack_flags |= obj->stack_flags; 2806 2807 dbg(" %p .. %p: %s", obj->mapbase, 2808 obj->mapbase + obj->mapsize - 1, obj->path); 2809 if (obj->textrel) 2810 dbg(" WARNING: %s has impure text", obj->path); 2811 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2812 obj->path); 2813 2814 return (obj); 2815 2816 errp: 2817 munmap(obj->mapbase, obj->mapsize); 2818 obj_free(obj); 2819 return (NULL); 2820 } 2821 2822 Obj_Entry * 2823 obj_from_addr(const void *addr) 2824 { 2825 Obj_Entry *obj; 2826 2827 TAILQ_FOREACH(obj, &obj_list, next) { 2828 if (obj->marker) 2829 continue; 2830 if (addr < (void *) obj->mapbase) 2831 continue; 2832 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2833 return obj; 2834 } 2835 return NULL; 2836 } 2837 2838 static void 2839 preinit_main(void) 2840 { 2841 Elf_Addr *preinit_addr; 2842 int index; 2843 2844 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2845 if (preinit_addr == NULL) 2846 return; 2847 2848 for (index = 0; index < obj_main->preinit_array_num; index++) { 2849 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2850 dbg("calling preinit function for %s at %p", obj_main->path, 2851 (void *)preinit_addr[index]); 2852 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2853 0, 0, obj_main->path); 2854 call_init_pointer(obj_main, preinit_addr[index]); 2855 } 2856 } 2857 } 2858 2859 /* 2860 * Call the finalization functions for each of the objects in "list" 2861 * belonging to the DAG of "root" and referenced once. If NULL "root" 2862 * is specified, every finalization function will be called regardless 2863 * of the reference count and the list elements won't be freed. All of 2864 * the objects are expected to have non-NULL fini functions. 2865 */ 2866 static void 2867 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2868 { 2869 Objlist_Entry *elm; 2870 struct dlerror_save *saved_msg; 2871 Elf_Addr *fini_addr; 2872 int index; 2873 2874 assert(root == NULL || root->refcount == 1); 2875 2876 if (root != NULL) 2877 root->doomed = true; 2878 2879 /* 2880 * Preserve the current error message since a fini function might 2881 * call into the dynamic linker and overwrite it. 2882 */ 2883 saved_msg = errmsg_save(); 2884 do { 2885 STAILQ_FOREACH(elm, list, link) { 2886 if (root != NULL && (elm->obj->refcount != 1 || 2887 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2888 continue; 2889 /* Remove object from fini list to prevent recursive invocation. */ 2890 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2891 /* Ensure that new references cannot be acquired. */ 2892 elm->obj->doomed = true; 2893 2894 hold_object(elm->obj); 2895 lock_release(rtld_bind_lock, lockstate); 2896 /* 2897 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2898 * When this happens, DT_FINI_ARRAY is processed first. 2899 */ 2900 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2901 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2902 for (index = elm->obj->fini_array_num - 1; index >= 0; 2903 index--) { 2904 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2905 dbg("calling fini function for %s at %p", 2906 elm->obj->path, (void *)fini_addr[index]); 2907 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2908 (void *)fini_addr[index], 0, 0, elm->obj->path); 2909 call_initfini_pointer(elm->obj, fini_addr[index]); 2910 } 2911 } 2912 } 2913 if (elm->obj->fini != (Elf_Addr)NULL) { 2914 dbg("calling fini function for %s at %p", elm->obj->path, 2915 (void *)elm->obj->fini); 2916 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2917 0, 0, elm->obj->path); 2918 call_initfini_pointer(elm->obj, elm->obj->fini); 2919 } 2920 wlock_acquire(rtld_bind_lock, lockstate); 2921 unhold_object(elm->obj); 2922 /* No need to free anything if process is going down. */ 2923 if (root != NULL) 2924 free(elm); 2925 /* 2926 * We must restart the list traversal after every fini call 2927 * because a dlclose() call from the fini function or from 2928 * another thread might have modified the reference counts. 2929 */ 2930 break; 2931 } 2932 } while (elm != NULL); 2933 errmsg_restore(saved_msg); 2934 } 2935 2936 /* 2937 * Call the initialization functions for each of the objects in 2938 * "list". All of the objects are expected to have non-NULL init 2939 * functions. 2940 */ 2941 static void 2942 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2943 { 2944 Objlist_Entry *elm; 2945 Obj_Entry *obj; 2946 struct dlerror_save *saved_msg; 2947 Elf_Addr *init_addr; 2948 void (*reg)(void (*)(void)); 2949 int index; 2950 2951 /* 2952 * Clean init_scanned flag so that objects can be rechecked and 2953 * possibly initialized earlier if any of vectors called below 2954 * cause the change by using dlopen. 2955 */ 2956 TAILQ_FOREACH(obj, &obj_list, next) { 2957 if (obj->marker) 2958 continue; 2959 obj->init_scanned = false; 2960 } 2961 2962 /* 2963 * Preserve the current error message since an init function might 2964 * call into the dynamic linker and overwrite it. 2965 */ 2966 saved_msg = errmsg_save(); 2967 STAILQ_FOREACH(elm, list, link) { 2968 if (elm->obj->init_done) /* Initialized early. */ 2969 continue; 2970 /* 2971 * Race: other thread might try to use this object before current 2972 * one completes the initialization. Not much can be done here 2973 * without better locking. 2974 */ 2975 elm->obj->init_done = true; 2976 hold_object(elm->obj); 2977 reg = NULL; 2978 if (elm->obj == obj_main && obj_main->crt_no_init) { 2979 reg = (void (*)(void (*)(void)))get_program_var_addr( 2980 "__libc_atexit", lockstate); 2981 } 2982 lock_release(rtld_bind_lock, lockstate); 2983 if (reg != NULL) { 2984 reg(rtld_exit); 2985 rtld_exit_ptr = rtld_nop_exit; 2986 } 2987 2988 /* 2989 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2990 * When this happens, DT_INIT is processed first. 2991 */ 2992 if (elm->obj->init != (Elf_Addr)NULL) { 2993 dbg("calling init function for %s at %p", elm->obj->path, 2994 (void *)elm->obj->init); 2995 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2996 0, 0, elm->obj->path); 2997 call_init_pointer(elm->obj, elm->obj->init); 2998 } 2999 init_addr = (Elf_Addr *)elm->obj->init_array; 3000 if (init_addr != NULL) { 3001 for (index = 0; index < elm->obj->init_array_num; index++) { 3002 if (init_addr[index] != 0 && init_addr[index] != 1) { 3003 dbg("calling init function for %s at %p", elm->obj->path, 3004 (void *)init_addr[index]); 3005 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3006 (void *)init_addr[index], 0, 0, elm->obj->path); 3007 call_init_pointer(elm->obj, init_addr[index]); 3008 } 3009 } 3010 } 3011 wlock_acquire(rtld_bind_lock, lockstate); 3012 unhold_object(elm->obj); 3013 } 3014 errmsg_restore(saved_msg); 3015 } 3016 3017 static void 3018 objlist_clear(Objlist *list) 3019 { 3020 Objlist_Entry *elm; 3021 3022 while (!STAILQ_EMPTY(list)) { 3023 elm = STAILQ_FIRST(list); 3024 STAILQ_REMOVE_HEAD(list, link); 3025 free(elm); 3026 } 3027 } 3028 3029 static Objlist_Entry * 3030 objlist_find(Objlist *list, const Obj_Entry *obj) 3031 { 3032 Objlist_Entry *elm; 3033 3034 STAILQ_FOREACH(elm, list, link) 3035 if (elm->obj == obj) 3036 return elm; 3037 return NULL; 3038 } 3039 3040 static void 3041 objlist_init(Objlist *list) 3042 { 3043 STAILQ_INIT(list); 3044 } 3045 3046 static void 3047 objlist_push_head(Objlist *list, Obj_Entry *obj) 3048 { 3049 Objlist_Entry *elm; 3050 3051 elm = NEW(Objlist_Entry); 3052 elm->obj = obj; 3053 STAILQ_INSERT_HEAD(list, elm, link); 3054 } 3055 3056 static void 3057 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3058 { 3059 Objlist_Entry *elm; 3060 3061 elm = NEW(Objlist_Entry); 3062 elm->obj = obj; 3063 STAILQ_INSERT_TAIL(list, elm, link); 3064 } 3065 3066 static void 3067 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3068 { 3069 Objlist_Entry *elm, *listelm; 3070 3071 STAILQ_FOREACH(listelm, list, link) { 3072 if (listelm->obj == listobj) 3073 break; 3074 } 3075 elm = NEW(Objlist_Entry); 3076 elm->obj = obj; 3077 if (listelm != NULL) 3078 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3079 else 3080 STAILQ_INSERT_TAIL(list, elm, link); 3081 } 3082 3083 static void 3084 objlist_remove(Objlist *list, Obj_Entry *obj) 3085 { 3086 Objlist_Entry *elm; 3087 3088 if ((elm = objlist_find(list, obj)) != NULL) { 3089 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3090 free(elm); 3091 } 3092 } 3093 3094 /* 3095 * Relocate dag rooted in the specified object. 3096 * Returns 0 on success, or -1 on failure. 3097 */ 3098 3099 static int 3100 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3101 int flags, RtldLockState *lockstate) 3102 { 3103 Objlist_Entry *elm; 3104 int error; 3105 3106 error = 0; 3107 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3108 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3109 lockstate); 3110 if (error == -1) 3111 break; 3112 } 3113 return (error); 3114 } 3115 3116 /* 3117 * Prepare for, or clean after, relocating an object marked with 3118 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3119 * segments are remapped read-write. After relocations are done, the 3120 * segment's permissions are returned back to the modes specified in 3121 * the phdrs. If any relocation happened, or always for wired 3122 * program, COW is triggered. 3123 */ 3124 static int 3125 reloc_textrel_prot(Obj_Entry *obj, bool before) 3126 { 3127 const Elf_Phdr *ph; 3128 void *base; 3129 size_t l, sz; 3130 int prot; 3131 3132 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3133 l--, ph++) { 3134 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3135 continue; 3136 base = obj->relocbase + trunc_page(ph->p_vaddr); 3137 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3138 trunc_page(ph->p_vaddr); 3139 prot = before ? (PROT_READ | PROT_WRITE) : 3140 convert_prot(ph->p_flags); 3141 if (mprotect(base, sz, prot) == -1) { 3142 _rtld_error("%s: Cannot write-%sable text segment: %s", 3143 obj->path, before ? "en" : "dis", 3144 rtld_strerror(errno)); 3145 return (-1); 3146 } 3147 } 3148 return (0); 3149 } 3150 3151 /* 3152 * Relocate single object. 3153 * Returns 0 on success, or -1 on failure. 3154 */ 3155 static int 3156 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3157 int flags, RtldLockState *lockstate) 3158 { 3159 3160 if (obj->relocated) 3161 return (0); 3162 obj->relocated = true; 3163 if (obj != rtldobj) 3164 dbg("relocating \"%s\"", obj->path); 3165 3166 if (obj->symtab == NULL || obj->strtab == NULL || 3167 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3168 dbg("object %s has no run-time symbol table", obj->path); 3169 3170 /* There are relocations to the write-protected text segment. */ 3171 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3172 return (-1); 3173 3174 /* Process the non-PLT non-IFUNC relocations. */ 3175 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3176 return (-1); 3177 3178 /* Re-protected the text segment. */ 3179 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3180 return (-1); 3181 3182 /* Set the special PLT or GOT entries. */ 3183 init_pltgot(obj); 3184 3185 /* Process the PLT relocations. */ 3186 if (reloc_plt(obj, flags, lockstate) == -1) 3187 return (-1); 3188 /* Relocate the jump slots if we are doing immediate binding. */ 3189 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3190 lockstate) == -1) 3191 return (-1); 3192 3193 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3194 return (-1); 3195 3196 /* 3197 * Set up the magic number and version in the Obj_Entry. These 3198 * were checked in the crt1.o from the original ElfKit, so we 3199 * set them for backward compatibility. 3200 */ 3201 obj->magic = RTLD_MAGIC; 3202 obj->version = RTLD_VERSION; 3203 3204 return (0); 3205 } 3206 3207 /* 3208 * Relocate newly-loaded shared objects. The argument is a pointer to 3209 * the Obj_Entry for the first such object. All objects from the first 3210 * to the end of the list of objects are relocated. Returns 0 on success, 3211 * or -1 on failure. 3212 */ 3213 static int 3214 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3215 int flags, RtldLockState *lockstate) 3216 { 3217 Obj_Entry *obj; 3218 int error; 3219 3220 for (error = 0, obj = first; obj != NULL; 3221 obj = TAILQ_NEXT(obj, next)) { 3222 if (obj->marker) 3223 continue; 3224 error = relocate_object(obj, bind_now, rtldobj, flags, 3225 lockstate); 3226 if (error == -1) 3227 break; 3228 } 3229 return (error); 3230 } 3231 3232 /* 3233 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3234 * referencing STT_GNU_IFUNC symbols is postponed till the other 3235 * relocations are done. The indirect functions specified as 3236 * ifunc are allowed to call other symbols, so we need to have 3237 * objects relocated before asking for resolution from indirects. 3238 * 3239 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3240 * instead of the usual lazy handling of PLT slots. It is 3241 * consistent with how GNU does it. 3242 */ 3243 static int 3244 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3245 RtldLockState *lockstate) 3246 { 3247 3248 if (obj->ifuncs_resolved) 3249 return (0); 3250 obj->ifuncs_resolved = true; 3251 if (!obj->irelative && !obj->irelative_nonplt && 3252 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3253 !obj->non_plt_gnu_ifunc) 3254 return (0); 3255 if (obj_disable_relro(obj) == -1 || 3256 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3257 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3258 lockstate) == -1) || 3259 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3260 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3261 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3262 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3263 obj_enforce_relro(obj) == -1) 3264 return (-1); 3265 return (0); 3266 } 3267 3268 static int 3269 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3270 RtldLockState *lockstate) 3271 { 3272 Objlist_Entry *elm; 3273 Obj_Entry *obj; 3274 3275 STAILQ_FOREACH(elm, list, link) { 3276 obj = elm->obj; 3277 if (obj->marker) 3278 continue; 3279 if (resolve_object_ifunc(obj, bind_now, flags, 3280 lockstate) == -1) 3281 return (-1); 3282 } 3283 return (0); 3284 } 3285 3286 /* 3287 * Cleanup procedure. It will be called (by the atexit mechanism) just 3288 * before the process exits. 3289 */ 3290 static void 3291 rtld_exit(void) 3292 { 3293 RtldLockState lockstate; 3294 3295 wlock_acquire(rtld_bind_lock, &lockstate); 3296 dbg("rtld_exit()"); 3297 objlist_call_fini(&list_fini, NULL, &lockstate); 3298 /* No need to remove the items from the list, since we are exiting. */ 3299 if (!libmap_disable) 3300 lm_fini(); 3301 lock_release(rtld_bind_lock, &lockstate); 3302 } 3303 3304 static void 3305 rtld_nop_exit(void) 3306 { 3307 } 3308 3309 /* 3310 * Iterate over a search path, translate each element, and invoke the 3311 * callback on the result. 3312 */ 3313 static void * 3314 path_enumerate(const char *path, path_enum_proc callback, 3315 const char *refobj_path, void *arg) 3316 { 3317 const char *trans; 3318 if (path == NULL) 3319 return (NULL); 3320 3321 path += strspn(path, ":;"); 3322 while (*path != '\0') { 3323 size_t len; 3324 char *res; 3325 3326 len = strcspn(path, ":;"); 3327 trans = lm_findn(refobj_path, path, len); 3328 if (trans) 3329 res = callback(trans, strlen(trans), arg); 3330 else 3331 res = callback(path, len, arg); 3332 3333 if (res != NULL) 3334 return (res); 3335 3336 path += len; 3337 path += strspn(path, ":;"); 3338 } 3339 3340 return (NULL); 3341 } 3342 3343 struct try_library_args { 3344 const char *name; 3345 size_t namelen; 3346 char *buffer; 3347 size_t buflen; 3348 int fd; 3349 }; 3350 3351 static void * 3352 try_library_path(const char *dir, size_t dirlen, void *param) 3353 { 3354 struct try_library_args *arg; 3355 int fd; 3356 3357 arg = param; 3358 if (*dir == '/' || trust) { 3359 char *pathname; 3360 3361 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3362 return (NULL); 3363 3364 pathname = arg->buffer; 3365 strncpy(pathname, dir, dirlen); 3366 pathname[dirlen] = '/'; 3367 strcpy(pathname + dirlen + 1, arg->name); 3368 3369 dbg(" Trying \"%s\"", pathname); 3370 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3371 if (fd >= 0) { 3372 dbg(" Opened \"%s\", fd %d", pathname, fd); 3373 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3374 strcpy(pathname, arg->buffer); 3375 arg->fd = fd; 3376 return (pathname); 3377 } else { 3378 dbg(" Failed to open \"%s\": %s", 3379 pathname, rtld_strerror(errno)); 3380 } 3381 } 3382 return (NULL); 3383 } 3384 3385 static char * 3386 search_library_path(const char *name, const char *path, 3387 const char *refobj_path, int *fdp) 3388 { 3389 char *p; 3390 struct try_library_args arg; 3391 3392 if (path == NULL) 3393 return NULL; 3394 3395 arg.name = name; 3396 arg.namelen = strlen(name); 3397 arg.buffer = xmalloc(PATH_MAX); 3398 arg.buflen = PATH_MAX; 3399 arg.fd = -1; 3400 3401 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3402 *fdp = arg.fd; 3403 3404 free(arg.buffer); 3405 3406 return (p); 3407 } 3408 3409 3410 /* 3411 * Finds the library with the given name using the directory descriptors 3412 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3413 * 3414 * Returns a freshly-opened close-on-exec file descriptor for the library, 3415 * or -1 if the library cannot be found. 3416 */ 3417 static char * 3418 search_library_pathfds(const char *name, const char *path, int *fdp) 3419 { 3420 char *envcopy, *fdstr, *found, *last_token; 3421 size_t len; 3422 int dirfd, fd; 3423 3424 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3425 3426 /* Don't load from user-specified libdirs into setuid binaries. */ 3427 if (!trust) 3428 return (NULL); 3429 3430 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3431 if (path == NULL) 3432 return (NULL); 3433 3434 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3435 if (name[0] == '/') { 3436 dbg("Absolute path (%s) passed to %s", name, __func__); 3437 return (NULL); 3438 } 3439 3440 /* 3441 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3442 * copy of the path, as strtok_r rewrites separator tokens 3443 * with '\0'. 3444 */ 3445 found = NULL; 3446 envcopy = xstrdup(path); 3447 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3448 fdstr = strtok_r(NULL, ":", &last_token)) { 3449 dirfd = parse_integer(fdstr); 3450 if (dirfd < 0) { 3451 _rtld_error("failed to parse directory FD: '%s'", 3452 fdstr); 3453 break; 3454 } 3455 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3456 if (fd >= 0) { 3457 *fdp = fd; 3458 len = strlen(fdstr) + strlen(name) + 3; 3459 found = xmalloc(len); 3460 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3461 _rtld_error("error generating '%d/%s'", 3462 dirfd, name); 3463 rtld_die(); 3464 } 3465 dbg("open('%s') => %d", found, fd); 3466 break; 3467 } 3468 } 3469 free(envcopy); 3470 3471 return (found); 3472 } 3473 3474 3475 int 3476 dlclose(void *handle) 3477 { 3478 RtldLockState lockstate; 3479 int error; 3480 3481 wlock_acquire(rtld_bind_lock, &lockstate); 3482 error = dlclose_locked(handle, &lockstate); 3483 lock_release(rtld_bind_lock, &lockstate); 3484 return (error); 3485 } 3486 3487 static int 3488 dlclose_locked(void *handle, RtldLockState *lockstate) 3489 { 3490 Obj_Entry *root; 3491 3492 root = dlcheck(handle); 3493 if (root == NULL) 3494 return -1; 3495 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3496 root->path); 3497 3498 /* Unreference the object and its dependencies. */ 3499 root->dl_refcount--; 3500 3501 if (root->refcount == 1) { 3502 /* 3503 * The object will be no longer referenced, so we must unload it. 3504 * First, call the fini functions. 3505 */ 3506 objlist_call_fini(&list_fini, root, lockstate); 3507 3508 unref_dag(root); 3509 3510 /* Finish cleaning up the newly-unreferenced objects. */ 3511 GDB_STATE(RT_DELETE,&root->linkmap); 3512 unload_object(root, lockstate); 3513 GDB_STATE(RT_CONSISTENT,NULL); 3514 } else 3515 unref_dag(root); 3516 3517 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3518 return 0; 3519 } 3520 3521 char * 3522 dlerror(void) 3523 { 3524 if (*(lockinfo.dlerror_seen()) != 0) 3525 return (NULL); 3526 *lockinfo.dlerror_seen() = 1; 3527 return (lockinfo.dlerror_loc()); 3528 } 3529 3530 /* 3531 * This function is deprecated and has no effect. 3532 */ 3533 void 3534 dllockinit(void *context, 3535 void *(*_lock_create)(void *context) __unused, 3536 void (*_rlock_acquire)(void *lock) __unused, 3537 void (*_wlock_acquire)(void *lock) __unused, 3538 void (*_lock_release)(void *lock) __unused, 3539 void (*_lock_destroy)(void *lock) __unused, 3540 void (*context_destroy)(void *context)) 3541 { 3542 static void *cur_context; 3543 static void (*cur_context_destroy)(void *); 3544 3545 /* Just destroy the context from the previous call, if necessary. */ 3546 if (cur_context_destroy != NULL) 3547 cur_context_destroy(cur_context); 3548 cur_context = context; 3549 cur_context_destroy = context_destroy; 3550 } 3551 3552 void * 3553 dlopen(const char *name, int mode) 3554 { 3555 3556 return (rtld_dlopen(name, -1, mode)); 3557 } 3558 3559 void * 3560 fdlopen(int fd, int mode) 3561 { 3562 3563 return (rtld_dlopen(NULL, fd, mode)); 3564 } 3565 3566 static void * 3567 rtld_dlopen(const char *name, int fd, int mode) 3568 { 3569 RtldLockState lockstate; 3570 int lo_flags; 3571 3572 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3573 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3574 if (ld_tracing != NULL) { 3575 rlock_acquire(rtld_bind_lock, &lockstate); 3576 if (sigsetjmp(lockstate.env, 0) != 0) 3577 lock_upgrade(rtld_bind_lock, &lockstate); 3578 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3579 lock_release(rtld_bind_lock, &lockstate); 3580 } 3581 lo_flags = RTLD_LO_DLOPEN; 3582 if (mode & RTLD_NODELETE) 3583 lo_flags |= RTLD_LO_NODELETE; 3584 if (mode & RTLD_NOLOAD) 3585 lo_flags |= RTLD_LO_NOLOAD; 3586 if (mode & RTLD_DEEPBIND) 3587 lo_flags |= RTLD_LO_DEEPBIND; 3588 if (ld_tracing != NULL) 3589 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3590 3591 return (dlopen_object(name, fd, obj_main, lo_flags, 3592 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3593 } 3594 3595 static void 3596 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3597 { 3598 3599 obj->dl_refcount--; 3600 unref_dag(obj); 3601 if (obj->refcount == 0) 3602 unload_object(obj, lockstate); 3603 } 3604 3605 static Obj_Entry * 3606 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3607 int mode, RtldLockState *lockstate) 3608 { 3609 Obj_Entry *old_obj_tail; 3610 Obj_Entry *obj; 3611 Objlist initlist; 3612 RtldLockState mlockstate; 3613 int result; 3614 3615 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3616 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3617 refobj->path, lo_flags, mode); 3618 objlist_init(&initlist); 3619 3620 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3621 wlock_acquire(rtld_bind_lock, &mlockstate); 3622 lockstate = &mlockstate; 3623 } 3624 GDB_STATE(RT_ADD,NULL); 3625 3626 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3627 obj = NULL; 3628 if (name == NULL && fd == -1) { 3629 obj = obj_main; 3630 obj->refcount++; 3631 } else { 3632 obj = load_object(name, fd, refobj, lo_flags); 3633 } 3634 3635 if (obj) { 3636 obj->dl_refcount++; 3637 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3638 objlist_push_tail(&list_global, obj); 3639 if (globallist_next(old_obj_tail) != NULL) { 3640 /* We loaded something new. */ 3641 assert(globallist_next(old_obj_tail) == obj); 3642 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3643 obj->symbolic = true; 3644 result = 0; 3645 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3646 obj->static_tls && !allocate_tls_offset(obj)) { 3647 _rtld_error("%s: No space available " 3648 "for static Thread Local Storage", obj->path); 3649 result = -1; 3650 } 3651 if (result != -1) 3652 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3653 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3654 init_dag(obj); 3655 ref_dag(obj); 3656 if (result != -1) 3657 result = rtld_verify_versions(&obj->dagmembers); 3658 if (result != -1 && ld_tracing) 3659 goto trace; 3660 if (result == -1 || relocate_object_dag(obj, 3661 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3662 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3663 lockstate) == -1) { 3664 dlopen_cleanup(obj, lockstate); 3665 obj = NULL; 3666 } else if (lo_flags & RTLD_LO_EARLY) { 3667 /* 3668 * Do not call the init functions for early loaded 3669 * filtees. The image is still not initialized enough 3670 * for them to work. 3671 * 3672 * Our object is found by the global object list and 3673 * will be ordered among all init calls done right 3674 * before transferring control to main. 3675 */ 3676 } else { 3677 /* Make list of init functions to call. */ 3678 initlist_add_objects(obj, obj, &initlist); 3679 } 3680 /* 3681 * Process all no_delete or global objects here, given 3682 * them own DAGs to prevent their dependencies from being 3683 * unloaded. This has to be done after we have loaded all 3684 * of the dependencies, so that we do not miss any. 3685 */ 3686 if (obj != NULL) 3687 process_z(obj); 3688 } else { 3689 /* 3690 * Bump the reference counts for objects on this DAG. If 3691 * this is the first dlopen() call for the object that was 3692 * already loaded as a dependency, initialize the dag 3693 * starting at it. 3694 */ 3695 init_dag(obj); 3696 ref_dag(obj); 3697 3698 if ((lo_flags & RTLD_LO_TRACE) != 0) 3699 goto trace; 3700 } 3701 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3702 obj->z_nodelete) && !obj->ref_nodel) { 3703 dbg("obj %s nodelete", obj->path); 3704 ref_dag(obj); 3705 obj->z_nodelete = obj->ref_nodel = true; 3706 } 3707 } 3708 3709 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3710 name); 3711 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3712 3713 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3714 map_stacks_exec(lockstate); 3715 if (obj != NULL) 3716 distribute_static_tls(&initlist, lockstate); 3717 } 3718 3719 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3720 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3721 lockstate) == -1) { 3722 objlist_clear(&initlist); 3723 dlopen_cleanup(obj, lockstate); 3724 if (lockstate == &mlockstate) 3725 lock_release(rtld_bind_lock, lockstate); 3726 return (NULL); 3727 } 3728 3729 if (!(lo_flags & RTLD_LO_EARLY)) { 3730 /* Call the init functions. */ 3731 objlist_call_init(&initlist, lockstate); 3732 } 3733 objlist_clear(&initlist); 3734 if (lockstate == &mlockstate) 3735 lock_release(rtld_bind_lock, lockstate); 3736 return obj; 3737 trace: 3738 trace_loaded_objects(obj); 3739 if (lockstate == &mlockstate) 3740 lock_release(rtld_bind_lock, lockstate); 3741 exit(0); 3742 } 3743 3744 static void * 3745 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3746 int flags) 3747 { 3748 DoneList donelist; 3749 const Obj_Entry *obj, *defobj; 3750 const Elf_Sym *def; 3751 SymLook req; 3752 RtldLockState lockstate; 3753 tls_index ti; 3754 void *sym; 3755 int res; 3756 3757 def = NULL; 3758 defobj = NULL; 3759 symlook_init(&req, name); 3760 req.ventry = ve; 3761 req.flags = flags | SYMLOOK_IN_PLT; 3762 req.lockstate = &lockstate; 3763 3764 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3765 rlock_acquire(rtld_bind_lock, &lockstate); 3766 if (sigsetjmp(lockstate.env, 0) != 0) 3767 lock_upgrade(rtld_bind_lock, &lockstate); 3768 if (handle == NULL || handle == RTLD_NEXT || 3769 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3770 3771 if ((obj = obj_from_addr(retaddr)) == NULL) { 3772 _rtld_error("Cannot determine caller's shared object"); 3773 lock_release(rtld_bind_lock, &lockstate); 3774 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3775 return NULL; 3776 } 3777 if (handle == NULL) { /* Just the caller's shared object. */ 3778 res = symlook_obj(&req, obj); 3779 if (res == 0) { 3780 def = req.sym_out; 3781 defobj = req.defobj_out; 3782 } 3783 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3784 handle == RTLD_SELF) { /* ... caller included */ 3785 if (handle == RTLD_NEXT) 3786 obj = globallist_next(obj); 3787 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3788 if (obj->marker) 3789 continue; 3790 res = symlook_obj(&req, obj); 3791 if (res == 0) { 3792 if (def == NULL || (ld_dynamic_weak && 3793 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3794 def = req.sym_out; 3795 defobj = req.defobj_out; 3796 if (!ld_dynamic_weak || 3797 ELF_ST_BIND(def->st_info) != STB_WEAK) 3798 break; 3799 } 3800 } 3801 } 3802 /* 3803 * Search the dynamic linker itself, and possibly resolve the 3804 * symbol from there. This is how the application links to 3805 * dynamic linker services such as dlopen. 3806 * Note that we ignore ld_dynamic_weak == false case, 3807 * always overriding weak symbols by rtld definitions. 3808 */ 3809 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3810 res = symlook_obj(&req, &obj_rtld); 3811 if (res == 0) { 3812 def = req.sym_out; 3813 defobj = req.defobj_out; 3814 } 3815 } 3816 } else { 3817 assert(handle == RTLD_DEFAULT); 3818 res = symlook_default(&req, obj); 3819 if (res == 0) { 3820 defobj = req.defobj_out; 3821 def = req.sym_out; 3822 } 3823 } 3824 } else { 3825 if ((obj = dlcheck(handle)) == NULL) { 3826 lock_release(rtld_bind_lock, &lockstate); 3827 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3828 return NULL; 3829 } 3830 3831 donelist_init(&donelist); 3832 if (obj->mainprog) { 3833 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3834 res = symlook_global(&req, &donelist); 3835 if (res == 0) { 3836 def = req.sym_out; 3837 defobj = req.defobj_out; 3838 } 3839 /* 3840 * Search the dynamic linker itself, and possibly resolve the 3841 * symbol from there. This is how the application links to 3842 * dynamic linker services such as dlopen. 3843 */ 3844 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3845 res = symlook_obj(&req, &obj_rtld); 3846 if (res == 0) { 3847 def = req.sym_out; 3848 defobj = req.defobj_out; 3849 } 3850 } 3851 } 3852 else { 3853 /* Search the whole DAG rooted at the given object. */ 3854 res = symlook_list(&req, &obj->dagmembers, &donelist); 3855 if (res == 0) { 3856 def = req.sym_out; 3857 defobj = req.defobj_out; 3858 } 3859 } 3860 } 3861 3862 if (def != NULL) { 3863 lock_release(rtld_bind_lock, &lockstate); 3864 3865 /* 3866 * The value required by the caller is derived from the value 3867 * of the symbol. this is simply the relocated value of the 3868 * symbol. 3869 */ 3870 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3871 sym = make_function_pointer(def, defobj); 3872 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3873 sym = rtld_resolve_ifunc(defobj, def); 3874 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3875 ti.ti_module = defobj->tlsindex; 3876 ti.ti_offset = def->st_value; 3877 sym = __tls_get_addr(&ti); 3878 } else 3879 sym = defobj->relocbase + def->st_value; 3880 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3881 return (sym); 3882 } 3883 3884 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3885 ve != NULL ? ve->name : ""); 3886 lock_release(rtld_bind_lock, &lockstate); 3887 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3888 return NULL; 3889 } 3890 3891 void * 3892 dlsym(void *handle, const char *name) 3893 { 3894 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3895 SYMLOOK_DLSYM); 3896 } 3897 3898 dlfunc_t 3899 dlfunc(void *handle, const char *name) 3900 { 3901 union { 3902 void *d; 3903 dlfunc_t f; 3904 } rv; 3905 3906 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3907 SYMLOOK_DLSYM); 3908 return (rv.f); 3909 } 3910 3911 void * 3912 dlvsym(void *handle, const char *name, const char *version) 3913 { 3914 Ver_Entry ventry; 3915 3916 ventry.name = version; 3917 ventry.file = NULL; 3918 ventry.hash = elf_hash(version); 3919 ventry.flags= 0; 3920 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3921 SYMLOOK_DLSYM); 3922 } 3923 3924 int 3925 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3926 { 3927 const Obj_Entry *obj; 3928 RtldLockState lockstate; 3929 3930 rlock_acquire(rtld_bind_lock, &lockstate); 3931 obj = obj_from_addr(addr); 3932 if (obj == NULL) { 3933 _rtld_error("No shared object contains address"); 3934 lock_release(rtld_bind_lock, &lockstate); 3935 return (0); 3936 } 3937 rtld_fill_dl_phdr_info(obj, phdr_info); 3938 lock_release(rtld_bind_lock, &lockstate); 3939 return (1); 3940 } 3941 3942 int 3943 dladdr(const void *addr, Dl_info *info) 3944 { 3945 const Obj_Entry *obj; 3946 const Elf_Sym *def; 3947 void *symbol_addr; 3948 unsigned long symoffset; 3949 RtldLockState lockstate; 3950 3951 rlock_acquire(rtld_bind_lock, &lockstate); 3952 obj = obj_from_addr(addr); 3953 if (obj == NULL) { 3954 _rtld_error("No shared object contains address"); 3955 lock_release(rtld_bind_lock, &lockstate); 3956 return 0; 3957 } 3958 info->dli_fname = obj->path; 3959 info->dli_fbase = obj->mapbase; 3960 info->dli_saddr = (void *)0; 3961 info->dli_sname = NULL; 3962 3963 /* 3964 * Walk the symbol list looking for the symbol whose address is 3965 * closest to the address sent in. 3966 */ 3967 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3968 def = obj->symtab + symoffset; 3969 3970 /* 3971 * For skip the symbol if st_shndx is either SHN_UNDEF or 3972 * SHN_COMMON. 3973 */ 3974 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3975 continue; 3976 3977 /* 3978 * If the symbol is greater than the specified address, or if it 3979 * is further away from addr than the current nearest symbol, 3980 * then reject it. 3981 */ 3982 symbol_addr = obj->relocbase + def->st_value; 3983 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3984 continue; 3985 3986 /* Update our idea of the nearest symbol. */ 3987 info->dli_sname = obj->strtab + def->st_name; 3988 info->dli_saddr = symbol_addr; 3989 3990 /* Exact match? */ 3991 if (info->dli_saddr == addr) 3992 break; 3993 } 3994 lock_release(rtld_bind_lock, &lockstate); 3995 return 1; 3996 } 3997 3998 int 3999 dlinfo(void *handle, int request, void *p) 4000 { 4001 const Obj_Entry *obj; 4002 RtldLockState lockstate; 4003 int error; 4004 4005 rlock_acquire(rtld_bind_lock, &lockstate); 4006 4007 if (handle == NULL || handle == RTLD_SELF) { 4008 void *retaddr; 4009 4010 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4011 if ((obj = obj_from_addr(retaddr)) == NULL) 4012 _rtld_error("Cannot determine caller's shared object"); 4013 } else 4014 obj = dlcheck(handle); 4015 4016 if (obj == NULL) { 4017 lock_release(rtld_bind_lock, &lockstate); 4018 return (-1); 4019 } 4020 4021 error = 0; 4022 switch (request) { 4023 case RTLD_DI_LINKMAP: 4024 *((struct link_map const **)p) = &obj->linkmap; 4025 break; 4026 case RTLD_DI_ORIGIN: 4027 error = rtld_dirname(obj->path, p); 4028 break; 4029 4030 case RTLD_DI_SERINFOSIZE: 4031 case RTLD_DI_SERINFO: 4032 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4033 break; 4034 4035 default: 4036 _rtld_error("Invalid request %d passed to dlinfo()", request); 4037 error = -1; 4038 } 4039 4040 lock_release(rtld_bind_lock, &lockstate); 4041 4042 return (error); 4043 } 4044 4045 static void 4046 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4047 { 4048 Elf_Addr **dtvp; 4049 4050 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4051 phdr_info->dlpi_name = obj->path; 4052 phdr_info->dlpi_phdr = obj->phdr; 4053 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4054 phdr_info->dlpi_tls_modid = obj->tlsindex; 4055 dtvp = _get_tp(); 4056 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4057 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4058 phdr_info->dlpi_adds = obj_loads; 4059 phdr_info->dlpi_subs = obj_loads - obj_count; 4060 } 4061 4062 int 4063 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4064 { 4065 struct dl_phdr_info phdr_info; 4066 Obj_Entry *obj, marker; 4067 RtldLockState bind_lockstate, phdr_lockstate; 4068 int error; 4069 4070 init_marker(&marker); 4071 error = 0; 4072 4073 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4074 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4075 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4076 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4077 rtld_fill_dl_phdr_info(obj, &phdr_info); 4078 hold_object(obj); 4079 lock_release(rtld_bind_lock, &bind_lockstate); 4080 4081 error = callback(&phdr_info, sizeof phdr_info, param); 4082 4083 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4084 unhold_object(obj); 4085 obj = globallist_next(&marker); 4086 TAILQ_REMOVE(&obj_list, &marker, next); 4087 if (error != 0) { 4088 lock_release(rtld_bind_lock, &bind_lockstate); 4089 lock_release(rtld_phdr_lock, &phdr_lockstate); 4090 return (error); 4091 } 4092 } 4093 4094 if (error == 0) { 4095 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4096 lock_release(rtld_bind_lock, &bind_lockstate); 4097 error = callback(&phdr_info, sizeof(phdr_info), param); 4098 } 4099 lock_release(rtld_phdr_lock, &phdr_lockstate); 4100 return (error); 4101 } 4102 4103 static void * 4104 fill_search_info(const char *dir, size_t dirlen, void *param) 4105 { 4106 struct fill_search_info_args *arg; 4107 4108 arg = param; 4109 4110 if (arg->request == RTLD_DI_SERINFOSIZE) { 4111 arg->serinfo->dls_cnt ++; 4112 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4113 } else { 4114 struct dl_serpath *s_entry; 4115 4116 s_entry = arg->serpath; 4117 s_entry->dls_name = arg->strspace; 4118 s_entry->dls_flags = arg->flags; 4119 4120 strncpy(arg->strspace, dir, dirlen); 4121 arg->strspace[dirlen] = '\0'; 4122 4123 arg->strspace += dirlen + 1; 4124 arg->serpath++; 4125 } 4126 4127 return (NULL); 4128 } 4129 4130 static int 4131 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4132 { 4133 struct dl_serinfo _info; 4134 struct fill_search_info_args args; 4135 4136 args.request = RTLD_DI_SERINFOSIZE; 4137 args.serinfo = &_info; 4138 4139 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4140 _info.dls_cnt = 0; 4141 4142 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4143 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4144 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4145 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4146 if (!obj->z_nodeflib) 4147 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4148 4149 4150 if (request == RTLD_DI_SERINFOSIZE) { 4151 info->dls_size = _info.dls_size; 4152 info->dls_cnt = _info.dls_cnt; 4153 return (0); 4154 } 4155 4156 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4157 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4158 return (-1); 4159 } 4160 4161 args.request = RTLD_DI_SERINFO; 4162 args.serinfo = info; 4163 args.serpath = &info->dls_serpath[0]; 4164 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4165 4166 args.flags = LA_SER_RUNPATH; 4167 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4168 return (-1); 4169 4170 args.flags = LA_SER_LIBPATH; 4171 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4172 return (-1); 4173 4174 args.flags = LA_SER_RUNPATH; 4175 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4176 return (-1); 4177 4178 args.flags = LA_SER_CONFIG; 4179 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4180 != NULL) 4181 return (-1); 4182 4183 args.flags = LA_SER_DEFAULT; 4184 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4185 fill_search_info, NULL, &args) != NULL) 4186 return (-1); 4187 return (0); 4188 } 4189 4190 static int 4191 rtld_dirname(const char *path, char *bname) 4192 { 4193 const char *endp; 4194 4195 /* Empty or NULL string gets treated as "." */ 4196 if (path == NULL || *path == '\0') { 4197 bname[0] = '.'; 4198 bname[1] = '\0'; 4199 return (0); 4200 } 4201 4202 /* Strip trailing slashes */ 4203 endp = path + strlen(path) - 1; 4204 while (endp > path && *endp == '/') 4205 endp--; 4206 4207 /* Find the start of the dir */ 4208 while (endp > path && *endp != '/') 4209 endp--; 4210 4211 /* Either the dir is "/" or there are no slashes */ 4212 if (endp == path) { 4213 bname[0] = *endp == '/' ? '/' : '.'; 4214 bname[1] = '\0'; 4215 return (0); 4216 } else { 4217 do { 4218 endp--; 4219 } while (endp > path && *endp == '/'); 4220 } 4221 4222 if (endp - path + 2 > PATH_MAX) 4223 { 4224 _rtld_error("Filename is too long: %s", path); 4225 return(-1); 4226 } 4227 4228 strncpy(bname, path, endp - path + 1); 4229 bname[endp - path + 1] = '\0'; 4230 return (0); 4231 } 4232 4233 static int 4234 rtld_dirname_abs(const char *path, char *base) 4235 { 4236 char *last; 4237 4238 if (realpath(path, base) == NULL) { 4239 _rtld_error("realpath \"%s\" failed (%s)", path, 4240 rtld_strerror(errno)); 4241 return (-1); 4242 } 4243 dbg("%s -> %s", path, base); 4244 last = strrchr(base, '/'); 4245 if (last == NULL) { 4246 _rtld_error("non-abs result from realpath \"%s\"", path); 4247 return (-1); 4248 } 4249 if (last != base) 4250 *last = '\0'; 4251 return (0); 4252 } 4253 4254 static void 4255 linkmap_add(Obj_Entry *obj) 4256 { 4257 struct link_map *l, *prev; 4258 4259 l = &obj->linkmap; 4260 l->l_name = obj->path; 4261 l->l_base = obj->mapbase; 4262 l->l_ld = obj->dynamic; 4263 l->l_addr = obj->relocbase; 4264 4265 if (r_debug.r_map == NULL) { 4266 r_debug.r_map = l; 4267 return; 4268 } 4269 4270 /* 4271 * Scan to the end of the list, but not past the entry for the 4272 * dynamic linker, which we want to keep at the very end. 4273 */ 4274 for (prev = r_debug.r_map; 4275 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4276 prev = prev->l_next) 4277 ; 4278 4279 /* Link in the new entry. */ 4280 l->l_prev = prev; 4281 l->l_next = prev->l_next; 4282 if (l->l_next != NULL) 4283 l->l_next->l_prev = l; 4284 prev->l_next = l; 4285 } 4286 4287 static void 4288 linkmap_delete(Obj_Entry *obj) 4289 { 4290 struct link_map *l; 4291 4292 l = &obj->linkmap; 4293 if (l->l_prev == NULL) { 4294 if ((r_debug.r_map = l->l_next) != NULL) 4295 l->l_next->l_prev = NULL; 4296 return; 4297 } 4298 4299 if ((l->l_prev->l_next = l->l_next) != NULL) 4300 l->l_next->l_prev = l->l_prev; 4301 } 4302 4303 /* 4304 * Function for the debugger to set a breakpoint on to gain control. 4305 * 4306 * The two parameters allow the debugger to easily find and determine 4307 * what the runtime loader is doing and to whom it is doing it. 4308 * 4309 * When the loadhook trap is hit (r_debug_state, set at program 4310 * initialization), the arguments can be found on the stack: 4311 * 4312 * +8 struct link_map *m 4313 * +4 struct r_debug *rd 4314 * +0 RetAddr 4315 */ 4316 void 4317 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4318 { 4319 /* 4320 * The following is a hack to force the compiler to emit calls to 4321 * this function, even when optimizing. If the function is empty, 4322 * the compiler is not obliged to emit any code for calls to it, 4323 * even when marked __noinline. However, gdb depends on those 4324 * calls being made. 4325 */ 4326 __compiler_membar(); 4327 } 4328 4329 /* 4330 * A function called after init routines have completed. This can be used to 4331 * break before a program's entry routine is called, and can be used when 4332 * main is not available in the symbol table. 4333 */ 4334 void 4335 _r_debug_postinit(struct link_map *m __unused) 4336 { 4337 4338 /* See r_debug_state(). */ 4339 __compiler_membar(); 4340 } 4341 4342 static void 4343 release_object(Obj_Entry *obj) 4344 { 4345 4346 if (obj->holdcount > 0) { 4347 obj->unholdfree = true; 4348 return; 4349 } 4350 munmap(obj->mapbase, obj->mapsize); 4351 linkmap_delete(obj); 4352 obj_free(obj); 4353 } 4354 4355 /* 4356 * Get address of the pointer variable in the main program. 4357 * Prefer non-weak symbol over the weak one. 4358 */ 4359 static const void ** 4360 get_program_var_addr(const char *name, RtldLockState *lockstate) 4361 { 4362 SymLook req; 4363 DoneList donelist; 4364 4365 symlook_init(&req, name); 4366 req.lockstate = lockstate; 4367 donelist_init(&donelist); 4368 if (symlook_global(&req, &donelist) != 0) 4369 return (NULL); 4370 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4371 return ((const void **)make_function_pointer(req.sym_out, 4372 req.defobj_out)); 4373 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4374 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4375 else 4376 return ((const void **)(req.defobj_out->relocbase + 4377 req.sym_out->st_value)); 4378 } 4379 4380 /* 4381 * Set a pointer variable in the main program to the given value. This 4382 * is used to set key variables such as "environ" before any of the 4383 * init functions are called. 4384 */ 4385 static void 4386 set_program_var(const char *name, const void *value) 4387 { 4388 const void **addr; 4389 4390 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4391 dbg("\"%s\": *%p <-- %p", name, addr, value); 4392 *addr = value; 4393 } 4394 } 4395 4396 /* 4397 * Search the global objects, including dependencies and main object, 4398 * for the given symbol. 4399 */ 4400 static int 4401 symlook_global(SymLook *req, DoneList *donelist) 4402 { 4403 SymLook req1; 4404 const Objlist_Entry *elm; 4405 int res; 4406 4407 symlook_init_from_req(&req1, req); 4408 4409 /* Search all objects loaded at program start up. */ 4410 if (req->defobj_out == NULL || (ld_dynamic_weak && 4411 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4412 res = symlook_list(&req1, &list_main, donelist); 4413 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4414 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4415 req->sym_out = req1.sym_out; 4416 req->defobj_out = req1.defobj_out; 4417 assert(req->defobj_out != NULL); 4418 } 4419 } 4420 4421 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4422 STAILQ_FOREACH(elm, &list_global, link) { 4423 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4424 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4425 break; 4426 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4427 if (res == 0 && (req->defobj_out == NULL || 4428 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4429 req->sym_out = req1.sym_out; 4430 req->defobj_out = req1.defobj_out; 4431 assert(req->defobj_out != NULL); 4432 } 4433 } 4434 4435 return (req->sym_out != NULL ? 0 : ESRCH); 4436 } 4437 4438 /* 4439 * Given a symbol name in a referencing object, find the corresponding 4440 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4441 * no definition was found. Returns a pointer to the Obj_Entry of the 4442 * defining object via the reference parameter DEFOBJ_OUT. 4443 */ 4444 static int 4445 symlook_default(SymLook *req, const Obj_Entry *refobj) 4446 { 4447 DoneList donelist; 4448 const Objlist_Entry *elm; 4449 SymLook req1; 4450 int res; 4451 4452 donelist_init(&donelist); 4453 symlook_init_from_req(&req1, req); 4454 4455 /* 4456 * Look first in the referencing object if linked symbolically, 4457 * and similarly handle protected symbols. 4458 */ 4459 res = symlook_obj(&req1, refobj); 4460 if (res == 0 && (refobj->symbolic || 4461 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4462 req->sym_out = req1.sym_out; 4463 req->defobj_out = req1.defobj_out; 4464 assert(req->defobj_out != NULL); 4465 } 4466 if (refobj->symbolic || req->defobj_out != NULL) 4467 donelist_check(&donelist, refobj); 4468 4469 symlook_global(req, &donelist); 4470 4471 /* Search all dlopened DAGs containing the referencing object. */ 4472 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4473 if (req->sym_out != NULL && (!ld_dynamic_weak || 4474 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4475 break; 4476 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4477 if (res == 0 && (req->sym_out == NULL || 4478 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4479 req->sym_out = req1.sym_out; 4480 req->defobj_out = req1.defobj_out; 4481 assert(req->defobj_out != NULL); 4482 } 4483 } 4484 4485 /* 4486 * Search the dynamic linker itself, and possibly resolve the 4487 * symbol from there. This is how the application links to 4488 * dynamic linker services such as dlopen. 4489 */ 4490 if (req->sym_out == NULL || 4491 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4492 res = symlook_obj(&req1, &obj_rtld); 4493 if (res == 0) { 4494 req->sym_out = req1.sym_out; 4495 req->defobj_out = req1.defobj_out; 4496 assert(req->defobj_out != NULL); 4497 } 4498 } 4499 4500 return (req->sym_out != NULL ? 0 : ESRCH); 4501 } 4502 4503 static int 4504 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4505 { 4506 const Elf_Sym *def; 4507 const Obj_Entry *defobj; 4508 const Objlist_Entry *elm; 4509 SymLook req1; 4510 int res; 4511 4512 def = NULL; 4513 defobj = NULL; 4514 STAILQ_FOREACH(elm, objlist, link) { 4515 if (donelist_check(dlp, elm->obj)) 4516 continue; 4517 symlook_init_from_req(&req1, req); 4518 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4519 if (def == NULL || (ld_dynamic_weak && 4520 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4521 def = req1.sym_out; 4522 defobj = req1.defobj_out; 4523 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4524 break; 4525 } 4526 } 4527 } 4528 if (def != NULL) { 4529 req->sym_out = def; 4530 req->defobj_out = defobj; 4531 return (0); 4532 } 4533 return (ESRCH); 4534 } 4535 4536 /* 4537 * Search the chain of DAGS cointed to by the given Needed_Entry 4538 * for a symbol of the given name. Each DAG is scanned completely 4539 * before advancing to the next one. Returns a pointer to the symbol, 4540 * or NULL if no definition was found. 4541 */ 4542 static int 4543 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4544 { 4545 const Elf_Sym *def; 4546 const Needed_Entry *n; 4547 const Obj_Entry *defobj; 4548 SymLook req1; 4549 int res; 4550 4551 def = NULL; 4552 defobj = NULL; 4553 symlook_init_from_req(&req1, req); 4554 for (n = needed; n != NULL; n = n->next) { 4555 if (n->obj == NULL || 4556 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4557 continue; 4558 if (def == NULL || (ld_dynamic_weak && 4559 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4560 def = req1.sym_out; 4561 defobj = req1.defobj_out; 4562 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4563 break; 4564 } 4565 } 4566 if (def != NULL) { 4567 req->sym_out = def; 4568 req->defobj_out = defobj; 4569 return (0); 4570 } 4571 return (ESRCH); 4572 } 4573 4574 /* 4575 * Search the symbol table of a single shared object for a symbol of 4576 * the given name and version, if requested. Returns a pointer to the 4577 * symbol, or NULL if no definition was found. If the object is 4578 * filter, return filtered symbol from filtee. 4579 * 4580 * The symbol's hash value is passed in for efficiency reasons; that 4581 * eliminates many recomputations of the hash value. 4582 */ 4583 int 4584 symlook_obj(SymLook *req, const Obj_Entry *obj) 4585 { 4586 DoneList donelist; 4587 SymLook req1; 4588 int flags, res, mres; 4589 4590 /* 4591 * If there is at least one valid hash at this point, we prefer to 4592 * use the faster GNU version if available. 4593 */ 4594 if (obj->valid_hash_gnu) 4595 mres = symlook_obj1_gnu(req, obj); 4596 else if (obj->valid_hash_sysv) 4597 mres = symlook_obj1_sysv(req, obj); 4598 else 4599 return (EINVAL); 4600 4601 if (mres == 0) { 4602 if (obj->needed_filtees != NULL) { 4603 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4604 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4605 donelist_init(&donelist); 4606 symlook_init_from_req(&req1, req); 4607 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4608 if (res == 0) { 4609 req->sym_out = req1.sym_out; 4610 req->defobj_out = req1.defobj_out; 4611 } 4612 return (res); 4613 } 4614 if (obj->needed_aux_filtees != NULL) { 4615 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4616 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4617 donelist_init(&donelist); 4618 symlook_init_from_req(&req1, req); 4619 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4620 if (res == 0) { 4621 req->sym_out = req1.sym_out; 4622 req->defobj_out = req1.defobj_out; 4623 return (res); 4624 } 4625 } 4626 } 4627 return (mres); 4628 } 4629 4630 /* Symbol match routine common to both hash functions */ 4631 static bool 4632 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4633 const unsigned long symnum) 4634 { 4635 Elf_Versym verndx; 4636 const Elf_Sym *symp; 4637 const char *strp; 4638 4639 symp = obj->symtab + symnum; 4640 strp = obj->strtab + symp->st_name; 4641 4642 switch (ELF_ST_TYPE(symp->st_info)) { 4643 case STT_FUNC: 4644 case STT_NOTYPE: 4645 case STT_OBJECT: 4646 case STT_COMMON: 4647 case STT_GNU_IFUNC: 4648 if (symp->st_value == 0) 4649 return (false); 4650 /* fallthrough */ 4651 case STT_TLS: 4652 if (symp->st_shndx != SHN_UNDEF) 4653 break; 4654 #ifndef __mips__ 4655 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4656 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4657 break; 4658 #endif 4659 /* fallthrough */ 4660 default: 4661 return (false); 4662 } 4663 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4664 return (false); 4665 4666 if (req->ventry == NULL) { 4667 if (obj->versyms != NULL) { 4668 verndx = VER_NDX(obj->versyms[symnum]); 4669 if (verndx > obj->vernum) { 4670 _rtld_error( 4671 "%s: symbol %s references wrong version %d", 4672 obj->path, obj->strtab + symnum, verndx); 4673 return (false); 4674 } 4675 /* 4676 * If we are not called from dlsym (i.e. this 4677 * is a normal relocation from unversioned 4678 * binary), accept the symbol immediately if 4679 * it happens to have first version after this 4680 * shared object became versioned. Otherwise, 4681 * if symbol is versioned and not hidden, 4682 * remember it. If it is the only symbol with 4683 * this name exported by the shared object, it 4684 * will be returned as a match by the calling 4685 * function. If symbol is global (verndx < 2) 4686 * accept it unconditionally. 4687 */ 4688 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4689 verndx == VER_NDX_GIVEN) { 4690 result->sym_out = symp; 4691 return (true); 4692 } 4693 else if (verndx >= VER_NDX_GIVEN) { 4694 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4695 == 0) { 4696 if (result->vsymp == NULL) 4697 result->vsymp = symp; 4698 result->vcount++; 4699 } 4700 return (false); 4701 } 4702 } 4703 result->sym_out = symp; 4704 return (true); 4705 } 4706 if (obj->versyms == NULL) { 4707 if (object_match_name(obj, req->ventry->name)) { 4708 _rtld_error("%s: object %s should provide version %s " 4709 "for symbol %s", obj_rtld.path, obj->path, 4710 req->ventry->name, obj->strtab + symnum); 4711 return (false); 4712 } 4713 } else { 4714 verndx = VER_NDX(obj->versyms[symnum]); 4715 if (verndx > obj->vernum) { 4716 _rtld_error("%s: symbol %s references wrong version %d", 4717 obj->path, obj->strtab + symnum, verndx); 4718 return (false); 4719 } 4720 if (obj->vertab[verndx].hash != req->ventry->hash || 4721 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4722 /* 4723 * Version does not match. Look if this is a 4724 * global symbol and if it is not hidden. If 4725 * global symbol (verndx < 2) is available, 4726 * use it. Do not return symbol if we are 4727 * called by dlvsym, because dlvsym looks for 4728 * a specific version and default one is not 4729 * what dlvsym wants. 4730 */ 4731 if ((req->flags & SYMLOOK_DLSYM) || 4732 (verndx >= VER_NDX_GIVEN) || 4733 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4734 return (false); 4735 } 4736 } 4737 result->sym_out = symp; 4738 return (true); 4739 } 4740 4741 /* 4742 * Search for symbol using SysV hash function. 4743 * obj->buckets is known not to be NULL at this point; the test for this was 4744 * performed with the obj->valid_hash_sysv assignment. 4745 */ 4746 static int 4747 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4748 { 4749 unsigned long symnum; 4750 Sym_Match_Result matchres; 4751 4752 matchres.sym_out = NULL; 4753 matchres.vsymp = NULL; 4754 matchres.vcount = 0; 4755 4756 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4757 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4758 if (symnum >= obj->nchains) 4759 return (ESRCH); /* Bad object */ 4760 4761 if (matched_symbol(req, obj, &matchres, symnum)) { 4762 req->sym_out = matchres.sym_out; 4763 req->defobj_out = obj; 4764 return (0); 4765 } 4766 } 4767 if (matchres.vcount == 1) { 4768 req->sym_out = matchres.vsymp; 4769 req->defobj_out = obj; 4770 return (0); 4771 } 4772 return (ESRCH); 4773 } 4774 4775 /* Search for symbol using GNU hash function */ 4776 static int 4777 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4778 { 4779 Elf_Addr bloom_word; 4780 const Elf32_Word *hashval; 4781 Elf32_Word bucket; 4782 Sym_Match_Result matchres; 4783 unsigned int h1, h2; 4784 unsigned long symnum; 4785 4786 matchres.sym_out = NULL; 4787 matchres.vsymp = NULL; 4788 matchres.vcount = 0; 4789 4790 /* Pick right bitmask word from Bloom filter array */ 4791 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4792 obj->maskwords_bm_gnu]; 4793 4794 /* Calculate modulus word size of gnu hash and its derivative */ 4795 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4796 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4797 4798 /* Filter out the "definitely not in set" queries */ 4799 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4800 return (ESRCH); 4801 4802 /* Locate hash chain and corresponding value element*/ 4803 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4804 if (bucket == 0) 4805 return (ESRCH); 4806 hashval = &obj->chain_zero_gnu[bucket]; 4807 do { 4808 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4809 symnum = hashval - obj->chain_zero_gnu; 4810 if (matched_symbol(req, obj, &matchres, symnum)) { 4811 req->sym_out = matchres.sym_out; 4812 req->defobj_out = obj; 4813 return (0); 4814 } 4815 } 4816 } while ((*hashval++ & 1) == 0); 4817 if (matchres.vcount == 1) { 4818 req->sym_out = matchres.vsymp; 4819 req->defobj_out = obj; 4820 return (0); 4821 } 4822 return (ESRCH); 4823 } 4824 4825 static void 4826 trace_loaded_objects(Obj_Entry *obj) 4827 { 4828 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4829 int c; 4830 4831 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4832 NULL) 4833 main_local = ""; 4834 4835 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4836 fmt1 = "\t%o => %p (%x)\n"; 4837 4838 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4839 fmt2 = "\t%o (%x)\n"; 4840 4841 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4842 4843 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4844 Needed_Entry *needed; 4845 const char *name, *path; 4846 bool is_lib; 4847 4848 if (obj->marker) 4849 continue; 4850 if (list_containers && obj->needed != NULL) 4851 rtld_printf("%s:\n", obj->path); 4852 for (needed = obj->needed; needed; needed = needed->next) { 4853 if (needed->obj != NULL) { 4854 if (needed->obj->traced && !list_containers) 4855 continue; 4856 needed->obj->traced = true; 4857 path = needed->obj->path; 4858 } else 4859 path = "not found"; 4860 4861 name = obj->strtab + needed->name; 4862 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4863 4864 fmt = is_lib ? fmt1 : fmt2; 4865 while ((c = *fmt++) != '\0') { 4866 switch (c) { 4867 default: 4868 rtld_putchar(c); 4869 continue; 4870 case '\\': 4871 switch (c = *fmt) { 4872 case '\0': 4873 continue; 4874 case 'n': 4875 rtld_putchar('\n'); 4876 break; 4877 case 't': 4878 rtld_putchar('\t'); 4879 break; 4880 } 4881 break; 4882 case '%': 4883 switch (c = *fmt) { 4884 case '\0': 4885 continue; 4886 case '%': 4887 default: 4888 rtld_putchar(c); 4889 break; 4890 case 'A': 4891 rtld_putstr(main_local); 4892 break; 4893 case 'a': 4894 rtld_putstr(obj_main->path); 4895 break; 4896 case 'o': 4897 rtld_putstr(name); 4898 break; 4899 #if 0 4900 case 'm': 4901 rtld_printf("%d", sodp->sod_major); 4902 break; 4903 case 'n': 4904 rtld_printf("%d", sodp->sod_minor); 4905 break; 4906 #endif 4907 case 'p': 4908 rtld_putstr(path); 4909 break; 4910 case 'x': 4911 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4912 0); 4913 break; 4914 } 4915 break; 4916 } 4917 ++fmt; 4918 } 4919 } 4920 } 4921 } 4922 4923 /* 4924 * Unload a dlopened object and its dependencies from memory and from 4925 * our data structures. It is assumed that the DAG rooted in the 4926 * object has already been unreferenced, and that the object has a 4927 * reference count of 0. 4928 */ 4929 static void 4930 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4931 { 4932 Obj_Entry marker, *obj, *next; 4933 4934 assert(root->refcount == 0); 4935 4936 /* 4937 * Pass over the DAG removing unreferenced objects from 4938 * appropriate lists. 4939 */ 4940 unlink_object(root); 4941 4942 /* Unmap all objects that are no longer referenced. */ 4943 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4944 next = TAILQ_NEXT(obj, next); 4945 if (obj->marker || obj->refcount != 0) 4946 continue; 4947 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4948 obj->mapsize, 0, obj->path); 4949 dbg("unloading \"%s\"", obj->path); 4950 /* 4951 * Unlink the object now to prevent new references from 4952 * being acquired while the bind lock is dropped in 4953 * recursive dlclose() invocations. 4954 */ 4955 TAILQ_REMOVE(&obj_list, obj, next); 4956 obj_count--; 4957 4958 if (obj->filtees_loaded) { 4959 if (next != NULL) { 4960 init_marker(&marker); 4961 TAILQ_INSERT_BEFORE(next, &marker, next); 4962 unload_filtees(obj, lockstate); 4963 next = TAILQ_NEXT(&marker, next); 4964 TAILQ_REMOVE(&obj_list, &marker, next); 4965 } else 4966 unload_filtees(obj, lockstate); 4967 } 4968 release_object(obj); 4969 } 4970 } 4971 4972 static void 4973 unlink_object(Obj_Entry *root) 4974 { 4975 Objlist_Entry *elm; 4976 4977 if (root->refcount == 0) { 4978 /* Remove the object from the RTLD_GLOBAL list. */ 4979 objlist_remove(&list_global, root); 4980 4981 /* Remove the object from all objects' DAG lists. */ 4982 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4983 objlist_remove(&elm->obj->dldags, root); 4984 if (elm->obj != root) 4985 unlink_object(elm->obj); 4986 } 4987 } 4988 } 4989 4990 static void 4991 ref_dag(Obj_Entry *root) 4992 { 4993 Objlist_Entry *elm; 4994 4995 assert(root->dag_inited); 4996 STAILQ_FOREACH(elm, &root->dagmembers, link) 4997 elm->obj->refcount++; 4998 } 4999 5000 static void 5001 unref_dag(Obj_Entry *root) 5002 { 5003 Objlist_Entry *elm; 5004 5005 assert(root->dag_inited); 5006 STAILQ_FOREACH(elm, &root->dagmembers, link) 5007 elm->obj->refcount--; 5008 } 5009 5010 /* 5011 * Common code for MD __tls_get_addr(). 5012 */ 5013 static void * 5014 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5015 { 5016 Elf_Addr *newdtv, *dtv; 5017 RtldLockState lockstate; 5018 int to_copy; 5019 5020 dtv = *dtvp; 5021 /* Check dtv generation in case new modules have arrived */ 5022 if (dtv[0] != tls_dtv_generation) { 5023 if (!locked) 5024 wlock_acquire(rtld_bind_lock, &lockstate); 5025 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5026 to_copy = dtv[1]; 5027 if (to_copy > tls_max_index) 5028 to_copy = tls_max_index; 5029 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5030 newdtv[0] = tls_dtv_generation; 5031 newdtv[1] = tls_max_index; 5032 free(dtv); 5033 if (!locked) 5034 lock_release(rtld_bind_lock, &lockstate); 5035 dtv = *dtvp = newdtv; 5036 } 5037 5038 /* Dynamically allocate module TLS if necessary */ 5039 if (dtv[index + 1] == 0) { 5040 /* Signal safe, wlock will block out signals. */ 5041 if (!locked) 5042 wlock_acquire(rtld_bind_lock, &lockstate); 5043 if (!dtv[index + 1]) 5044 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5045 if (!locked) 5046 lock_release(rtld_bind_lock, &lockstate); 5047 } 5048 return ((void *)(dtv[index + 1] + offset)); 5049 } 5050 5051 void * 5052 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 5053 { 5054 Elf_Addr *dtv; 5055 5056 dtv = *dtvp; 5057 /* Check dtv generation in case new modules have arrived */ 5058 if (__predict_true(dtv[0] == tls_dtv_generation && 5059 dtv[index + 1] != 0)) 5060 return ((void *)(dtv[index + 1] + offset)); 5061 return (tls_get_addr_slow(dtvp, index, offset, false)); 5062 } 5063 5064 #ifdef TLS_VARIANT_I 5065 5066 /* 5067 * Return pointer to allocated TLS block 5068 */ 5069 static void * 5070 get_tls_block_ptr(void *tcb, size_t tcbsize) 5071 { 5072 size_t extra_size, post_size, pre_size, tls_block_size; 5073 size_t tls_init_align; 5074 5075 tls_init_align = MAX(obj_main->tlsalign, 1); 5076 5077 /* Compute fragments sizes. */ 5078 extra_size = tcbsize - TLS_TCB_SIZE; 5079 post_size = calculate_tls_post_size(tls_init_align); 5080 tls_block_size = tcbsize + post_size; 5081 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5082 5083 return ((char *)tcb - pre_size - extra_size); 5084 } 5085 5086 /* 5087 * Allocate Static TLS using the Variant I method. 5088 * 5089 * For details on the layout, see lib/libc/gen/tls.c. 5090 * 5091 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5092 * it is based on tls_last_offset, and TLS offsets here are really TCB 5093 * offsets, whereas libc's tls_static_space is just the executable's static 5094 * TLS segment. 5095 */ 5096 void * 5097 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5098 { 5099 Obj_Entry *obj; 5100 char *tls_block; 5101 Elf_Addr *dtv, **tcb; 5102 Elf_Addr addr; 5103 Elf_Addr i; 5104 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5105 size_t tls_init_align, tls_init_offset; 5106 5107 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5108 return (oldtcb); 5109 5110 assert(tcbsize >= TLS_TCB_SIZE); 5111 maxalign = MAX(tcbalign, tls_static_max_align); 5112 tls_init_align = MAX(obj_main->tlsalign, 1); 5113 5114 /* Compute fragmets sizes. */ 5115 extra_size = tcbsize - TLS_TCB_SIZE; 5116 post_size = calculate_tls_post_size(tls_init_align); 5117 tls_block_size = tcbsize + post_size; 5118 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5119 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5120 5121 /* Allocate whole TLS block */ 5122 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5123 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5124 5125 if (oldtcb != NULL) { 5126 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5127 tls_static_space); 5128 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5129 5130 /* Adjust the DTV. */ 5131 dtv = tcb[0]; 5132 for (i = 0; i < dtv[1]; i++) { 5133 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5134 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5135 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5136 } 5137 } 5138 } else { 5139 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5140 tcb[0] = dtv; 5141 dtv[0] = tls_dtv_generation; 5142 dtv[1] = tls_max_index; 5143 5144 for (obj = globallist_curr(objs); obj != NULL; 5145 obj = globallist_next(obj)) { 5146 if (obj->tlsoffset == 0) 5147 continue; 5148 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5149 addr = (Elf_Addr)tcb + obj->tlsoffset; 5150 if (tls_init_offset > 0) 5151 memset((void *)addr, 0, tls_init_offset); 5152 if (obj->tlsinitsize > 0) { 5153 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5154 obj->tlsinitsize); 5155 } 5156 if (obj->tlssize > obj->tlsinitsize) { 5157 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5158 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5159 } 5160 dtv[obj->tlsindex + 1] = addr; 5161 } 5162 } 5163 5164 return (tcb); 5165 } 5166 5167 void 5168 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5169 { 5170 Elf_Addr *dtv; 5171 Elf_Addr tlsstart, tlsend; 5172 size_t post_size; 5173 size_t dtvsize, i, tls_init_align; 5174 5175 assert(tcbsize >= TLS_TCB_SIZE); 5176 tls_init_align = MAX(obj_main->tlsalign, 1); 5177 5178 /* Compute fragments sizes. */ 5179 post_size = calculate_tls_post_size(tls_init_align); 5180 5181 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5182 tlsend = (Elf_Addr)tcb + tls_static_space; 5183 5184 dtv = *(Elf_Addr **)tcb; 5185 dtvsize = dtv[1]; 5186 for (i = 0; i < dtvsize; i++) { 5187 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5188 free((void*)dtv[i+2]); 5189 } 5190 } 5191 free(dtv); 5192 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5193 } 5194 5195 #endif /* TLS_VARIANT_I */ 5196 5197 #ifdef TLS_VARIANT_II 5198 5199 /* 5200 * Allocate Static TLS using the Variant II method. 5201 */ 5202 void * 5203 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5204 { 5205 Obj_Entry *obj; 5206 size_t size, ralign; 5207 char *tls; 5208 Elf_Addr *dtv, *olddtv; 5209 Elf_Addr segbase, oldsegbase, addr; 5210 size_t i; 5211 5212 ralign = tcbalign; 5213 if (tls_static_max_align > ralign) 5214 ralign = tls_static_max_align; 5215 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5216 5217 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5218 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5219 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5220 5221 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5222 ((Elf_Addr*)segbase)[0] = segbase; 5223 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5224 5225 dtv[0] = tls_dtv_generation; 5226 dtv[1] = tls_max_index; 5227 5228 if (oldtls) { 5229 /* 5230 * Copy the static TLS block over whole. 5231 */ 5232 oldsegbase = (Elf_Addr) oldtls; 5233 memcpy((void *)(segbase - tls_static_space), 5234 (const void *)(oldsegbase - tls_static_space), 5235 tls_static_space); 5236 5237 /* 5238 * If any dynamic TLS blocks have been created tls_get_addr(), 5239 * move them over. 5240 */ 5241 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5242 for (i = 0; i < olddtv[1]; i++) { 5243 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5244 dtv[i+2] = olddtv[i+2]; 5245 olddtv[i+2] = 0; 5246 } 5247 } 5248 5249 /* 5250 * We assume that this block was the one we created with 5251 * allocate_initial_tls(). 5252 */ 5253 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5254 } else { 5255 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5256 if (obj->marker || obj->tlsoffset == 0) 5257 continue; 5258 addr = segbase - obj->tlsoffset; 5259 memset((void*)(addr + obj->tlsinitsize), 5260 0, obj->tlssize - obj->tlsinitsize); 5261 if (obj->tlsinit) { 5262 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5263 obj->static_tls_copied = true; 5264 } 5265 dtv[obj->tlsindex + 1] = addr; 5266 } 5267 } 5268 5269 return (void*) segbase; 5270 } 5271 5272 void 5273 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5274 { 5275 Elf_Addr* dtv; 5276 size_t size, ralign; 5277 int dtvsize, i; 5278 Elf_Addr tlsstart, tlsend; 5279 5280 /* 5281 * Figure out the size of the initial TLS block so that we can 5282 * find stuff which ___tls_get_addr() allocated dynamically. 5283 */ 5284 ralign = tcbalign; 5285 if (tls_static_max_align > ralign) 5286 ralign = tls_static_max_align; 5287 size = roundup(tls_static_space, ralign); 5288 5289 dtv = ((Elf_Addr**)tls)[1]; 5290 dtvsize = dtv[1]; 5291 tlsend = (Elf_Addr) tls; 5292 tlsstart = tlsend - size; 5293 for (i = 0; i < dtvsize; i++) { 5294 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5295 free_aligned((void *)dtv[i + 2]); 5296 } 5297 } 5298 5299 free_aligned((void *)tlsstart); 5300 free((void*) dtv); 5301 } 5302 5303 #endif /* TLS_VARIANT_II */ 5304 5305 /* 5306 * Allocate TLS block for module with given index. 5307 */ 5308 void * 5309 allocate_module_tls(int index) 5310 { 5311 Obj_Entry *obj; 5312 char *p; 5313 5314 TAILQ_FOREACH(obj, &obj_list, next) { 5315 if (obj->marker) 5316 continue; 5317 if (obj->tlsindex == index) 5318 break; 5319 } 5320 if (obj == NULL) { 5321 _rtld_error("Can't find module with TLS index %d", index); 5322 rtld_die(); 5323 } 5324 5325 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5326 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5327 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5328 return (p); 5329 } 5330 5331 bool 5332 allocate_tls_offset(Obj_Entry *obj) 5333 { 5334 size_t off; 5335 5336 if (obj->tls_done) 5337 return true; 5338 5339 if (obj->tlssize == 0) { 5340 obj->tls_done = true; 5341 return true; 5342 } 5343 5344 if (tls_last_offset == 0) 5345 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5346 obj->tlspoffset); 5347 else 5348 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5349 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5350 5351 obj->tlsoffset = off; 5352 #ifdef TLS_VARIANT_I 5353 off += obj->tlssize; 5354 #endif 5355 5356 /* 5357 * If we have already fixed the size of the static TLS block, we 5358 * must stay within that size. When allocating the static TLS, we 5359 * leave a small amount of space spare to be used for dynamically 5360 * loading modules which use static TLS. 5361 */ 5362 if (tls_static_space != 0) { 5363 if (off > tls_static_space) 5364 return false; 5365 } else if (obj->tlsalign > tls_static_max_align) { 5366 tls_static_max_align = obj->tlsalign; 5367 } 5368 5369 tls_last_offset = off; 5370 tls_last_size = obj->tlssize; 5371 obj->tls_done = true; 5372 5373 return true; 5374 } 5375 5376 void 5377 free_tls_offset(Obj_Entry *obj) 5378 { 5379 5380 /* 5381 * If we were the last thing to allocate out of the static TLS 5382 * block, we give our space back to the 'allocator'. This is a 5383 * simplistic workaround to allow libGL.so.1 to be loaded and 5384 * unloaded multiple times. 5385 */ 5386 size_t off = obj->tlsoffset; 5387 #ifdef TLS_VARIANT_I 5388 off += obj->tlssize; 5389 #endif 5390 if (off == tls_last_offset) { 5391 tls_last_offset -= obj->tlssize; 5392 tls_last_size = 0; 5393 } 5394 } 5395 5396 void * 5397 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5398 { 5399 void *ret; 5400 RtldLockState lockstate; 5401 5402 wlock_acquire(rtld_bind_lock, &lockstate); 5403 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5404 tcbsize, tcbalign); 5405 lock_release(rtld_bind_lock, &lockstate); 5406 return (ret); 5407 } 5408 5409 void 5410 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5411 { 5412 RtldLockState lockstate; 5413 5414 wlock_acquire(rtld_bind_lock, &lockstate); 5415 free_tls(tcb, tcbsize, tcbalign); 5416 lock_release(rtld_bind_lock, &lockstate); 5417 } 5418 5419 static void 5420 object_add_name(Obj_Entry *obj, const char *name) 5421 { 5422 Name_Entry *entry; 5423 size_t len; 5424 5425 len = strlen(name); 5426 entry = malloc(sizeof(Name_Entry) + len); 5427 5428 if (entry != NULL) { 5429 strcpy(entry->name, name); 5430 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5431 } 5432 } 5433 5434 static int 5435 object_match_name(const Obj_Entry *obj, const char *name) 5436 { 5437 Name_Entry *entry; 5438 5439 STAILQ_FOREACH(entry, &obj->names, link) { 5440 if (strcmp(name, entry->name) == 0) 5441 return (1); 5442 } 5443 return (0); 5444 } 5445 5446 static Obj_Entry * 5447 locate_dependency(const Obj_Entry *obj, const char *name) 5448 { 5449 const Objlist_Entry *entry; 5450 const Needed_Entry *needed; 5451 5452 STAILQ_FOREACH(entry, &list_main, link) { 5453 if (object_match_name(entry->obj, name)) 5454 return entry->obj; 5455 } 5456 5457 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5458 if (strcmp(obj->strtab + needed->name, name) == 0 || 5459 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5460 /* 5461 * If there is DT_NEEDED for the name we are looking for, 5462 * we are all set. Note that object might not be found if 5463 * dependency was not loaded yet, so the function can 5464 * return NULL here. This is expected and handled 5465 * properly by the caller. 5466 */ 5467 return (needed->obj); 5468 } 5469 } 5470 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5471 obj->path, name); 5472 rtld_die(); 5473 } 5474 5475 static int 5476 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5477 const Elf_Vernaux *vna) 5478 { 5479 const Elf_Verdef *vd; 5480 const char *vername; 5481 5482 vername = refobj->strtab + vna->vna_name; 5483 vd = depobj->verdef; 5484 if (vd == NULL) { 5485 _rtld_error("%s: version %s required by %s not defined", 5486 depobj->path, vername, refobj->path); 5487 return (-1); 5488 } 5489 for (;;) { 5490 if (vd->vd_version != VER_DEF_CURRENT) { 5491 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5492 depobj->path, vd->vd_version); 5493 return (-1); 5494 } 5495 if (vna->vna_hash == vd->vd_hash) { 5496 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5497 ((const char *)vd + vd->vd_aux); 5498 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5499 return (0); 5500 } 5501 if (vd->vd_next == 0) 5502 break; 5503 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5504 } 5505 if (vna->vna_flags & VER_FLG_WEAK) 5506 return (0); 5507 _rtld_error("%s: version %s required by %s not found", 5508 depobj->path, vername, refobj->path); 5509 return (-1); 5510 } 5511 5512 static int 5513 rtld_verify_object_versions(Obj_Entry *obj) 5514 { 5515 const Elf_Verneed *vn; 5516 const Elf_Verdef *vd; 5517 const Elf_Verdaux *vda; 5518 const Elf_Vernaux *vna; 5519 const Obj_Entry *depobj; 5520 int maxvernum, vernum; 5521 5522 if (obj->ver_checked) 5523 return (0); 5524 obj->ver_checked = true; 5525 5526 maxvernum = 0; 5527 /* 5528 * Walk over defined and required version records and figure out 5529 * max index used by any of them. Do very basic sanity checking 5530 * while there. 5531 */ 5532 vn = obj->verneed; 5533 while (vn != NULL) { 5534 if (vn->vn_version != VER_NEED_CURRENT) { 5535 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5536 obj->path, vn->vn_version); 5537 return (-1); 5538 } 5539 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5540 for (;;) { 5541 vernum = VER_NEED_IDX(vna->vna_other); 5542 if (vernum > maxvernum) 5543 maxvernum = vernum; 5544 if (vna->vna_next == 0) 5545 break; 5546 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5547 } 5548 if (vn->vn_next == 0) 5549 break; 5550 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5551 } 5552 5553 vd = obj->verdef; 5554 while (vd != NULL) { 5555 if (vd->vd_version != VER_DEF_CURRENT) { 5556 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5557 obj->path, vd->vd_version); 5558 return (-1); 5559 } 5560 vernum = VER_DEF_IDX(vd->vd_ndx); 5561 if (vernum > maxvernum) 5562 maxvernum = vernum; 5563 if (vd->vd_next == 0) 5564 break; 5565 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5566 } 5567 5568 if (maxvernum == 0) 5569 return (0); 5570 5571 /* 5572 * Store version information in array indexable by version index. 5573 * Verify that object version requirements are satisfied along the 5574 * way. 5575 */ 5576 obj->vernum = maxvernum + 1; 5577 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5578 5579 vd = obj->verdef; 5580 while (vd != NULL) { 5581 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5582 vernum = VER_DEF_IDX(vd->vd_ndx); 5583 assert(vernum <= maxvernum); 5584 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5585 obj->vertab[vernum].hash = vd->vd_hash; 5586 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5587 obj->vertab[vernum].file = NULL; 5588 obj->vertab[vernum].flags = 0; 5589 } 5590 if (vd->vd_next == 0) 5591 break; 5592 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5593 } 5594 5595 vn = obj->verneed; 5596 while (vn != NULL) { 5597 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5598 if (depobj == NULL) 5599 return (-1); 5600 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5601 for (;;) { 5602 if (check_object_provided_version(obj, depobj, vna)) 5603 return (-1); 5604 vernum = VER_NEED_IDX(vna->vna_other); 5605 assert(vernum <= maxvernum); 5606 obj->vertab[vernum].hash = vna->vna_hash; 5607 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5608 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5609 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5610 VER_INFO_HIDDEN : 0; 5611 if (vna->vna_next == 0) 5612 break; 5613 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5614 } 5615 if (vn->vn_next == 0) 5616 break; 5617 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5618 } 5619 return 0; 5620 } 5621 5622 static int 5623 rtld_verify_versions(const Objlist *objlist) 5624 { 5625 Objlist_Entry *entry; 5626 int rc; 5627 5628 rc = 0; 5629 STAILQ_FOREACH(entry, objlist, link) { 5630 /* 5631 * Skip dummy objects or objects that have their version requirements 5632 * already checked. 5633 */ 5634 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5635 continue; 5636 if (rtld_verify_object_versions(entry->obj) == -1) { 5637 rc = -1; 5638 if (ld_tracing == NULL) 5639 break; 5640 } 5641 } 5642 if (rc == 0 || ld_tracing != NULL) 5643 rc = rtld_verify_object_versions(&obj_rtld); 5644 return rc; 5645 } 5646 5647 const Ver_Entry * 5648 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5649 { 5650 Elf_Versym vernum; 5651 5652 if (obj->vertab) { 5653 vernum = VER_NDX(obj->versyms[symnum]); 5654 if (vernum >= obj->vernum) { 5655 _rtld_error("%s: symbol %s has wrong verneed value %d", 5656 obj->path, obj->strtab + symnum, vernum); 5657 } else if (obj->vertab[vernum].hash != 0) { 5658 return &obj->vertab[vernum]; 5659 } 5660 } 5661 return NULL; 5662 } 5663 5664 int 5665 _rtld_get_stack_prot(void) 5666 { 5667 5668 return (stack_prot); 5669 } 5670 5671 int 5672 _rtld_is_dlopened(void *arg) 5673 { 5674 Obj_Entry *obj; 5675 RtldLockState lockstate; 5676 int res; 5677 5678 rlock_acquire(rtld_bind_lock, &lockstate); 5679 obj = dlcheck(arg); 5680 if (obj == NULL) 5681 obj = obj_from_addr(arg); 5682 if (obj == NULL) { 5683 _rtld_error("No shared object contains address"); 5684 lock_release(rtld_bind_lock, &lockstate); 5685 return (-1); 5686 } 5687 res = obj->dlopened ? 1 : 0; 5688 lock_release(rtld_bind_lock, &lockstate); 5689 return (res); 5690 } 5691 5692 static int 5693 obj_remap_relro(Obj_Entry *obj, int prot) 5694 { 5695 5696 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5697 prot) == -1) { 5698 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5699 obj->path, prot, rtld_strerror(errno)); 5700 return (-1); 5701 } 5702 return (0); 5703 } 5704 5705 static int 5706 obj_disable_relro(Obj_Entry *obj) 5707 { 5708 5709 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5710 } 5711 5712 static int 5713 obj_enforce_relro(Obj_Entry *obj) 5714 { 5715 5716 return (obj_remap_relro(obj, PROT_READ)); 5717 } 5718 5719 static void 5720 map_stacks_exec(RtldLockState *lockstate) 5721 { 5722 void (*thr_map_stacks_exec)(void); 5723 5724 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5725 return; 5726 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5727 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5728 if (thr_map_stacks_exec != NULL) { 5729 stack_prot |= PROT_EXEC; 5730 thr_map_stacks_exec(); 5731 } 5732 } 5733 5734 static void 5735 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5736 { 5737 Objlist_Entry *elm; 5738 Obj_Entry *obj; 5739 void (*distrib)(size_t, void *, size_t, size_t); 5740 5741 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5742 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5743 if (distrib == NULL) 5744 return; 5745 STAILQ_FOREACH(elm, list, link) { 5746 obj = elm->obj; 5747 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5748 continue; 5749 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5750 obj->tlssize); 5751 obj->static_tls_copied = true; 5752 } 5753 } 5754 5755 void 5756 symlook_init(SymLook *dst, const char *name) 5757 { 5758 5759 bzero(dst, sizeof(*dst)); 5760 dst->name = name; 5761 dst->hash = elf_hash(name); 5762 dst->hash_gnu = gnu_hash(name); 5763 } 5764 5765 static void 5766 symlook_init_from_req(SymLook *dst, const SymLook *src) 5767 { 5768 5769 dst->name = src->name; 5770 dst->hash = src->hash; 5771 dst->hash_gnu = src->hash_gnu; 5772 dst->ventry = src->ventry; 5773 dst->flags = src->flags; 5774 dst->defobj_out = NULL; 5775 dst->sym_out = NULL; 5776 dst->lockstate = src->lockstate; 5777 } 5778 5779 static int 5780 open_binary_fd(const char *argv0, bool search_in_path, 5781 const char **binpath_res) 5782 { 5783 char *binpath, *pathenv, *pe, *res1; 5784 const char *res; 5785 int fd; 5786 5787 binpath = NULL; 5788 res = NULL; 5789 if (search_in_path && strchr(argv0, '/') == NULL) { 5790 binpath = xmalloc(PATH_MAX); 5791 pathenv = getenv("PATH"); 5792 if (pathenv == NULL) { 5793 _rtld_error("-p and no PATH environment variable"); 5794 rtld_die(); 5795 } 5796 pathenv = strdup(pathenv); 5797 if (pathenv == NULL) { 5798 _rtld_error("Cannot allocate memory"); 5799 rtld_die(); 5800 } 5801 fd = -1; 5802 errno = ENOENT; 5803 while ((pe = strsep(&pathenv, ":")) != NULL) { 5804 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5805 continue; 5806 if (binpath[0] != '\0' && 5807 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5808 continue; 5809 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5810 continue; 5811 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5812 if (fd != -1 || errno != ENOENT) { 5813 res = binpath; 5814 break; 5815 } 5816 } 5817 free(pathenv); 5818 } else { 5819 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5820 res = argv0; 5821 } 5822 5823 if (fd == -1) { 5824 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5825 rtld_die(); 5826 } 5827 if (res != NULL && res[0] != '/') { 5828 res1 = xmalloc(PATH_MAX); 5829 if (realpath(res, res1) != NULL) { 5830 if (res != argv0) 5831 free(__DECONST(char *, res)); 5832 res = res1; 5833 } else { 5834 free(res1); 5835 } 5836 } 5837 *binpath_res = res; 5838 return (fd); 5839 } 5840 5841 /* 5842 * Parse a set of command-line arguments. 5843 */ 5844 static int 5845 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5846 const char **argv0, bool *dir_ignore) 5847 { 5848 const char *arg; 5849 char machine[64]; 5850 size_t sz; 5851 int arglen, fd, i, j, mib[2]; 5852 char opt; 5853 bool seen_b, seen_f; 5854 5855 dbg("Parsing command-line arguments"); 5856 *use_pathp = false; 5857 *fdp = -1; 5858 *dir_ignore = false; 5859 seen_b = seen_f = false; 5860 5861 for (i = 1; i < argc; i++ ) { 5862 arg = argv[i]; 5863 dbg("argv[%d]: '%s'", i, arg); 5864 5865 /* 5866 * rtld arguments end with an explicit "--" or with the first 5867 * non-prefixed argument. 5868 */ 5869 if (strcmp(arg, "--") == 0) { 5870 i++; 5871 break; 5872 } 5873 if (arg[0] != '-') 5874 break; 5875 5876 /* 5877 * All other arguments are single-character options that can 5878 * be combined, so we need to search through `arg` for them. 5879 */ 5880 arglen = strlen(arg); 5881 for (j = 1; j < arglen; j++) { 5882 opt = arg[j]; 5883 if (opt == 'h') { 5884 print_usage(argv[0]); 5885 _exit(0); 5886 } else if (opt == 'b') { 5887 if (seen_f) { 5888 _rtld_error("Both -b and -f specified"); 5889 rtld_die(); 5890 } 5891 i++; 5892 *argv0 = argv[i]; 5893 seen_b = true; 5894 break; 5895 } else if (opt == 'd') { 5896 *dir_ignore = true; 5897 break; 5898 } else if (opt == 'f') { 5899 if (seen_b) { 5900 _rtld_error("Both -b and -f specified"); 5901 rtld_die(); 5902 } 5903 5904 /* 5905 * -f XX can be used to specify a 5906 * descriptor for the binary named at 5907 * the command line (i.e., the later 5908 * argument will specify the process 5909 * name but the descriptor is what 5910 * will actually be executed). 5911 * 5912 * -f must be the last option in, e.g., -abcf. 5913 */ 5914 if (j != arglen - 1) { 5915 _rtld_error("Invalid options: %s", arg); 5916 rtld_die(); 5917 } 5918 i++; 5919 fd = parse_integer(argv[i]); 5920 if (fd == -1) { 5921 _rtld_error( 5922 "Invalid file descriptor: '%s'", 5923 argv[i]); 5924 rtld_die(); 5925 } 5926 *fdp = fd; 5927 seen_f = true; 5928 break; 5929 } else if (opt == 'p') { 5930 *use_pathp = true; 5931 } else if (opt == 'u') { 5932 trust = false; 5933 } else if (opt == 'v') { 5934 machine[0] = '\0'; 5935 mib[0] = CTL_HW; 5936 mib[1] = HW_MACHINE; 5937 sz = sizeof(machine); 5938 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5939 rtld_printf( 5940 "FreeBSD ld-elf.so.1 %s\n" 5941 "FreeBSD_version %d\n" 5942 "Default lib path %s\n" 5943 "Env prefix %s\n" 5944 "Hint file %s\n" 5945 "libmap file %s\n", 5946 machine, 5947 __FreeBSD_version, ld_standard_library_path, 5948 ld_env_prefix, ld_elf_hints_default, 5949 ld_path_libmap_conf); 5950 _exit(0); 5951 } else { 5952 _rtld_error("Invalid argument: '%s'", arg); 5953 print_usage(argv[0]); 5954 rtld_die(); 5955 } 5956 } 5957 } 5958 5959 if (!seen_b) 5960 *argv0 = argv[i]; 5961 return (i); 5962 } 5963 5964 /* 5965 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5966 */ 5967 static int 5968 parse_integer(const char *str) 5969 { 5970 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5971 const char *orig; 5972 int n; 5973 char c; 5974 5975 orig = str; 5976 n = 0; 5977 for (c = *str; c != '\0'; c = *++str) { 5978 if (c < '0' || c > '9') 5979 return (-1); 5980 5981 n *= RADIX; 5982 n += c - '0'; 5983 } 5984 5985 /* Make sure we actually parsed something. */ 5986 if (str == orig) 5987 return (-1); 5988 return (n); 5989 } 5990 5991 static void 5992 print_usage(const char *argv0) 5993 { 5994 5995 rtld_printf( 5996 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5997 "\n" 5998 "Options:\n" 5999 " -h Display this help message\n" 6000 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6001 " -d Ignore lack of exec permissions for the binary\n" 6002 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6003 " -p Search in PATH for named binary\n" 6004 " -u Ignore LD_ environment variables\n" 6005 " -v Display identification information\n" 6006 " -- End of RTLD options\n" 6007 " <binary> Name of process to execute\n" 6008 " <args> Arguments to the executed process\n", argv0); 6009 } 6010 6011 /* 6012 * Overrides for libc_pic-provided functions. 6013 */ 6014 6015 int 6016 __getosreldate(void) 6017 { 6018 size_t len; 6019 int oid[2]; 6020 int error, osrel; 6021 6022 if (osreldate != 0) 6023 return (osreldate); 6024 6025 oid[0] = CTL_KERN; 6026 oid[1] = KERN_OSRELDATE; 6027 osrel = 0; 6028 len = sizeof(osrel); 6029 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6030 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6031 osreldate = osrel; 6032 return (osreldate); 6033 } 6034 const char * 6035 rtld_strerror(int errnum) 6036 { 6037 6038 if (errnum < 0 || errnum >= sys_nerr) 6039 return ("Unknown error"); 6040 return (sys_errlist[errnum]); 6041 } 6042 6043 char * 6044 getenv(const char *name) 6045 { 6046 return (__DECONST(char *, rtld_get_env_val(environ, name, 6047 strlen(name)))); 6048 } 6049 6050 /* malloc */ 6051 void * 6052 malloc(size_t nbytes) 6053 { 6054 6055 return (__crt_malloc(nbytes)); 6056 } 6057 6058 void * 6059 calloc(size_t num, size_t size) 6060 { 6061 6062 return (__crt_calloc(num, size)); 6063 } 6064 6065 void 6066 free(void *cp) 6067 { 6068 6069 __crt_free(cp); 6070 } 6071 6072 void * 6073 realloc(void *cp, size_t nbytes) 6074 { 6075 6076 return (__crt_realloc(cp, nbytes)); 6077 } 6078 6079 extern int _rtld_version__FreeBSD_version __exported; 6080 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6081 6082 extern char _rtld_version_laddr_offset __exported; 6083 char _rtld_version_laddr_offset; 6084 6085 extern char _rtld_version_dlpi_tls_data __exported; 6086 char _rtld_version_dlpi_tls_data; 6087