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