1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 #include <sys/param.h> 43 #include <sys/mount.h> 44 #include <sys/mman.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/uio.h> 48 #include <sys/utsname.h> 49 #include <sys/ktrace.h> 50 51 #include <dlfcn.h> 52 #include <err.h> 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <stdarg.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 #include "debug.h" 62 #include "rtld.h" 63 #include "libmap.h" 64 #include "rtld_paths.h" 65 #include "rtld_tls.h" 66 #include "rtld_printf.h" 67 #include "rtld_malloc.h" 68 #include "rtld_utrace.h" 69 #include "notes.h" 70 #include "rtld_libc.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(void); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 77 /* Variables that cannot be static: */ 78 extern struct r_debug r_debug; /* For GDB */ 79 extern int _thread_autoinit_dummy_decl; 80 extern void (*__cleanup)(void); 81 82 struct dlerror_save { 83 int seen; 84 char *msg; 85 }; 86 87 /* 88 * Function declarations. 89 */ 90 static const char *basename(const char *); 91 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 92 const Elf_Dyn **, const Elf_Dyn **); 93 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 94 const Elf_Dyn *); 95 static bool digest_dynamic(Obj_Entry *, int); 96 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 97 static void distribute_static_tls(Objlist *, RtldLockState *); 98 static Obj_Entry *dlcheck(void *); 99 static int dlclose_locked(void *, RtldLockState *); 100 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 101 int lo_flags, int mode, RtldLockState *lockstate); 102 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 103 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 104 static bool donelist_check(DoneList *, const Obj_Entry *); 105 static void dump_auxv(Elf_Auxinfo **aux_info); 106 static void errmsg_restore(struct dlerror_save *); 107 static struct dlerror_save *errmsg_save(void); 108 static void *fill_search_info(const char *, size_t, void *); 109 static char *find_library(const char *, const Obj_Entry *, int *); 110 static const char *gethints(bool); 111 static void hold_object(Obj_Entry *); 112 static void unhold_object(Obj_Entry *); 113 static void init_dag(Obj_Entry *); 114 static void init_marker(Obj_Entry *); 115 static void init_pagesizes(Elf_Auxinfo **aux_info); 116 static void init_rtld(caddr_t, Elf_Auxinfo **); 117 static void initlist_add_neededs(Needed_Entry *, Objlist *); 118 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 119 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 120 static void linkmap_add(Obj_Entry *); 121 static void linkmap_delete(Obj_Entry *); 122 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 123 static void unload_filtees(Obj_Entry *, RtldLockState *); 124 static int load_needed_objects(Obj_Entry *, int); 125 static int load_preload_objects(const char *, bool); 126 static int load_kpreload(const void *addr); 127 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 128 static void map_stacks_exec(RtldLockState *); 129 static int obj_disable_relro(Obj_Entry *); 130 static int obj_enforce_relro(Obj_Entry *); 131 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 132 static void objlist_call_init(Objlist *, RtldLockState *); 133 static void objlist_clear(Objlist *); 134 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 135 static void objlist_init(Objlist *); 136 static void objlist_push_head(Objlist *, Obj_Entry *); 137 static void objlist_push_tail(Objlist *, Obj_Entry *); 138 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 139 static void objlist_remove(Objlist *, Obj_Entry *); 140 static int open_binary_fd(const char *argv0, bool search_in_path, 141 const char **binpath_res); 142 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 143 const char **argv0, bool *dir_ignore); 144 static int parse_integer(const char *); 145 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 146 static void print_usage(const char *argv0); 147 static void release_object(Obj_Entry *); 148 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 149 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 150 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 151 int flags, RtldLockState *lockstate); 152 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 153 RtldLockState *); 154 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 155 static int rtld_dirname(const char *, char *); 156 static int rtld_dirname_abs(const char *, char *); 157 static void *rtld_dlopen(const char *name, int fd, int mode); 158 static void rtld_exit(void); 159 static void rtld_nop_exit(void); 160 static char *search_library_path(const char *, const char *, const char *, 161 int *); 162 static char *search_library_pathfds(const char *, const char *, int *); 163 static const void **get_program_var_addr(const char *, RtldLockState *); 164 static void set_program_var(const char *, const void *); 165 static int symlook_default(SymLook *, const Obj_Entry *refobj); 166 static int symlook_global(SymLook *, DoneList *); 167 static void symlook_init_from_req(SymLook *, const SymLook *); 168 static int symlook_list(SymLook *, const Objlist *, DoneList *); 169 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 170 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 171 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 172 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 173 static void trace_loaded_objects(Obj_Entry *, bool); 174 static void unlink_object(Obj_Entry *); 175 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 176 static void unref_dag(Obj_Entry *); 177 static void ref_dag(Obj_Entry *); 178 static char *origin_subst_one(Obj_Entry *, char *, const char *, 179 const char *, bool); 180 static char *origin_subst(Obj_Entry *, const char *); 181 static bool obj_resolve_origin(Obj_Entry *obj); 182 static void preinit_main(void); 183 static int rtld_verify_versions(const Objlist *); 184 static int rtld_verify_object_versions(Obj_Entry *); 185 static void object_add_name(Obj_Entry *, const char *); 186 static int object_match_name(const Obj_Entry *, const char *); 187 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 188 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 189 struct dl_phdr_info *phdr_info); 190 static uint32_t gnu_hash(const char *); 191 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 192 const unsigned long); 193 194 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 195 void _r_debug_postinit(struct link_map *) __noinline __exported; 196 197 int __sys_openat(int, const char *, int, ...); 198 199 /* 200 * Data declarations. 201 */ 202 struct r_debug r_debug __exported; /* for GDB; */ 203 static bool libmap_disable; /* Disable libmap */ 204 static bool ld_loadfltr; /* Immediate filters processing */ 205 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 206 static bool trust; /* False for setuid and setgid programs */ 207 static bool dangerous_ld_env; /* True if environment variables have been 208 used to affect the libraries loaded */ 209 bool ld_bind_not; /* Disable PLT update */ 210 static const char *ld_bind_now; /* Environment variable for immediate binding */ 211 static const char *ld_debug; /* Environment variable for debugging */ 212 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 213 weak definition */ 214 static const char *ld_library_path;/* Environment variable for search path */ 215 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 216 static const char *ld_preload; /* Environment variable for libraries to 217 load first */ 218 static const char *ld_preload_fds;/* Environment variable for libraries represented by 219 descriptors */ 220 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 221 static const char *ld_tracing; /* Called from ldd to print libs */ 222 static const char *ld_utrace; /* Use utrace() to log events. */ 223 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 224 static Obj_Entry *obj_main; /* The main program shared object */ 225 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 226 static unsigned int obj_count; /* Number of objects in obj_list */ 227 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 228 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */ 229 RTLD_STATIC_TLS_EXTRA; 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 int npagesizes; 268 static int osreldate; 269 size_t *pagesizes; 270 size_t page_size; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 struct ld_env_var_desc { 348 const char * const n; 349 const char *val; 350 const bool unsecure; 351 }; 352 #define LD_ENV_DESC(var, unsec) \ 353 [LD_##var] = { .n = #var, .unsecure = unsec } 354 355 static struct ld_env_var_desc ld_env_vars[] = { 356 LD_ENV_DESC(BIND_NOW, false), 357 LD_ENV_DESC(PRELOAD, true), 358 LD_ENV_DESC(LIBMAP, true), 359 LD_ENV_DESC(LIBRARY_PATH, true), 360 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 361 LD_ENV_DESC(LIBMAP_DISABLE, true), 362 LD_ENV_DESC(BIND_NOT, true), 363 LD_ENV_DESC(DEBUG, true), 364 LD_ENV_DESC(ELF_HINTS_PATH, true), 365 LD_ENV_DESC(LOADFLTR, true), 366 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 367 LD_ENV_DESC(PRELOAD_FDS, true), 368 LD_ENV_DESC(DYNAMIC_WEAK, true), 369 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 370 LD_ENV_DESC(UTRACE, false), 371 LD_ENV_DESC(DUMP_REL_PRE, false), 372 LD_ENV_DESC(DUMP_REL_POST, false), 373 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 374 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 375 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 376 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 377 LD_ENV_DESC(SHOW_AUXV, false), 378 LD_ENV_DESC(STATIC_TLS_EXTRA, false), 379 LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false), 380 }; 381 382 const char * 383 ld_get_env_var(int idx) 384 { 385 return (ld_env_vars[idx].val); 386 } 387 388 static const char * 389 rtld_get_env_val(char **env, const char *name, size_t name_len) 390 { 391 char **m, *n, *v; 392 393 for (m = env; *m != NULL; m++) { 394 n = *m; 395 v = strchr(n, '='); 396 if (v == NULL) { 397 /* corrupt environment? */ 398 continue; 399 } 400 if (v - n == (ptrdiff_t)name_len && 401 strncmp(name, n, name_len) == 0) 402 return (v + 1); 403 } 404 return (NULL); 405 } 406 407 static void 408 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 409 { 410 struct ld_env_var_desc *lvd; 411 size_t prefix_len, nlen; 412 char **m, *n, *v; 413 int i; 414 415 prefix_len = strlen(env_prefix); 416 for (m = env; *m != NULL; m++) { 417 n = *m; 418 if (strncmp(env_prefix, n, prefix_len) != 0) { 419 /* Not a rtld environment variable. */ 420 continue; 421 } 422 n += prefix_len; 423 v = strchr(n, '='); 424 if (v == NULL) { 425 /* corrupt environment? */ 426 continue; 427 } 428 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 429 lvd = &ld_env_vars[i]; 430 if (lvd->val != NULL) { 431 /* Saw higher-priority variable name already. */ 432 continue; 433 } 434 nlen = strlen(lvd->n); 435 if (v - n == (ptrdiff_t)nlen && 436 strncmp(lvd->n, n, nlen) == 0) { 437 lvd->val = v + 1; 438 break; 439 } 440 } 441 } 442 } 443 444 static void 445 rtld_init_env_vars(char **env) 446 { 447 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 448 } 449 450 static void 451 set_ld_elf_hints_path(void) 452 { 453 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 454 ld_elf_hints_path = ld_elf_hints_default; 455 } 456 457 uintptr_t 458 rtld_round_page(uintptr_t x) 459 { 460 return (roundup2(x, page_size)); 461 } 462 463 uintptr_t 464 rtld_trunc_page(uintptr_t x) 465 { 466 return (rounddown2(x, page_size)); 467 } 468 469 /* 470 * Main entry point for dynamic linking. The first argument is the 471 * stack pointer. The stack is expected to be laid out as described 472 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 473 * Specifically, the stack pointer points to a word containing 474 * ARGC. Following that in the stack is a null-terminated sequence 475 * of pointers to argument strings. Then comes a null-terminated 476 * sequence of pointers to environment strings. Finally, there is a 477 * sequence of "auxiliary vector" entries. 478 * 479 * The second argument points to a place to store the dynamic linker's 480 * exit procedure pointer and the third to a place to store the main 481 * program's object. 482 * 483 * The return value is the main program's entry point. 484 */ 485 func_ptr_type 486 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 487 { 488 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 489 Objlist_Entry *entry; 490 Obj_Entry *last_interposer, *obj, *preload_tail; 491 const Elf_Phdr *phdr; 492 Objlist initlist; 493 RtldLockState lockstate; 494 struct stat st; 495 Elf_Addr *argcp; 496 char **argv, **env, **envp, *kexecpath; 497 const char *argv0, *binpath, *library_path_rpath, *static_tls_extra; 498 struct ld_env_var_desc *lvd; 499 caddr_t imgentry; 500 char buf[MAXPATHLEN]; 501 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 502 size_t sz; 503 #ifdef __powerpc__ 504 int old_auxv_format = 1; 505 #endif 506 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 507 508 /* 509 * On entry, the dynamic linker itself has not been relocated yet. 510 * Be very careful not to reference any global data until after 511 * init_rtld has returned. It is OK to reference file-scope statics 512 * and string constants, and to call static and global functions. 513 */ 514 515 /* Find the auxiliary vector on the stack. */ 516 argcp = sp; 517 argc = *sp++; 518 argv = (char **) sp; 519 sp += argc + 1; /* Skip over arguments and NULL terminator */ 520 env = (char **) sp; 521 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 522 ; 523 aux = (Elf_Auxinfo *) sp; 524 525 /* Digest the auxiliary vector. */ 526 for (i = 0; i < AT_COUNT; i++) 527 aux_info[i] = NULL; 528 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 529 if (auxp->a_type < AT_COUNT) 530 aux_info[auxp->a_type] = auxp; 531 #ifdef __powerpc__ 532 if (auxp->a_type == 23) /* AT_STACKPROT */ 533 old_auxv_format = 0; 534 #endif 535 } 536 537 #ifdef __powerpc__ 538 if (old_auxv_format) { 539 /* Remap from old-style auxv numbers. */ 540 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 541 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 542 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 543 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 544 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 545 aux_info[13] = NULL; /* AT_GID */ 546 547 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 548 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 549 aux_info[16] = aux_info[14]; /* AT_CANARY */ 550 aux_info[14] = NULL; /* AT_EGID */ 551 } 552 #endif 553 554 /* Initialize and relocate ourselves. */ 555 assert(aux_info[AT_BASE] != NULL); 556 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 557 558 dlerror_dflt_init(); 559 560 __progname = obj_rtld.path; 561 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 562 environ = env; 563 main_argc = argc; 564 main_argv = argv; 565 566 if (aux_info[AT_BSDFLAGS] != NULL && 567 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 568 ld_fast_sigblock = true; 569 570 trust = !issetugid(); 571 direct_exec = false; 572 573 md_abi_variant_hook(aux_info); 574 rtld_init_env_vars(env); 575 576 fd = -1; 577 if (aux_info[AT_EXECFD] != NULL) { 578 fd = aux_info[AT_EXECFD]->a_un.a_val; 579 } else { 580 assert(aux_info[AT_PHDR] != NULL); 581 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 582 if (phdr == obj_rtld.phdr) { 583 if (!trust) { 584 _rtld_error("Tainted process refusing to run binary %s", 585 argv0); 586 rtld_die(); 587 } 588 direct_exec = true; 589 590 dbg("opening main program in direct exec mode"); 591 if (argc >= 2) { 592 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 593 &argv0, &dir_ignore); 594 explicit_fd = (fd != -1); 595 binpath = NULL; 596 if (!explicit_fd) 597 fd = open_binary_fd(argv0, search_in_path, &binpath); 598 if (fstat(fd, &st) == -1) { 599 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 600 explicit_fd ? "user-provided descriptor" : argv0, 601 rtld_strerror(errno)); 602 rtld_die(); 603 } 604 605 /* 606 * Rough emulation of the permission checks done by 607 * execve(2), only Unix DACs are checked, ACLs are 608 * ignored. Preserve the semantic of disabling owner 609 * to execute if owner x bit is cleared, even if 610 * others x bit is enabled. 611 * mmap(2) does not allow to mmap with PROT_EXEC if 612 * binary' file comes from noexec mount. We cannot 613 * set a text reference on the binary. 614 */ 615 dir_enable = false; 616 if (st.st_uid == geteuid()) { 617 if ((st.st_mode & S_IXUSR) != 0) 618 dir_enable = true; 619 } else if (st.st_gid == getegid()) { 620 if ((st.st_mode & S_IXGRP) != 0) 621 dir_enable = true; 622 } else if ((st.st_mode & S_IXOTH) != 0) { 623 dir_enable = true; 624 } 625 if (!dir_enable && !dir_ignore) { 626 _rtld_error("No execute permission for binary %s", 627 argv0); 628 rtld_die(); 629 } 630 631 /* 632 * For direct exec mode, argv[0] is the interpreter 633 * name, we must remove it and shift arguments left 634 * before invoking binary main. Since stack layout 635 * places environment pointers and aux vectors right 636 * after the terminating NULL, we must shift 637 * environment and aux as well. 638 */ 639 main_argc = argc - rtld_argc; 640 for (i = 0; i <= main_argc; i++) 641 argv[i] = argv[i + rtld_argc]; 642 *argcp -= rtld_argc; 643 environ = env = envp = argv + main_argc + 1; 644 dbg("move env from %p to %p", envp + rtld_argc, envp); 645 do { 646 *envp = *(envp + rtld_argc); 647 } while (*envp++ != NULL); 648 aux = auxp = (Elf_Auxinfo *)envp; 649 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 650 dbg("move aux from %p to %p", auxpf, aux); 651 /* XXXKIB insert place for AT_EXECPATH if not present */ 652 for (;; auxp++, auxpf++) { 653 *auxp = *auxpf; 654 if (auxp->a_type == AT_NULL) 655 break; 656 } 657 /* Since the auxiliary vector has moved, redigest it. */ 658 for (i = 0; i < AT_COUNT; i++) 659 aux_info[i] = NULL; 660 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 661 if (auxp->a_type < AT_COUNT) 662 aux_info[auxp->a_type] = auxp; 663 } 664 665 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 666 if (binpath == NULL) { 667 aux_info[AT_EXECPATH] = NULL; 668 } else { 669 if (aux_info[AT_EXECPATH] == NULL) { 670 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 671 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 672 } 673 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 674 binpath); 675 } 676 } else { 677 _rtld_error("No binary"); 678 rtld_die(); 679 } 680 } 681 } 682 683 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 684 685 /* 686 * If the process is tainted, then we un-set the dangerous environment 687 * variables. The process will be marked as tainted until setuid(2) 688 * is called. If any child process calls setuid(2) we do not want any 689 * future processes to honor the potentially un-safe variables. 690 */ 691 if (!trust) { 692 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 693 lvd = &ld_env_vars[i]; 694 if (lvd->unsecure) 695 lvd->val = NULL; 696 } 697 } 698 699 ld_debug = ld_get_env_var(LD_DEBUG); 700 if (ld_bind_now == NULL) 701 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 702 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 703 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 704 libmap_override = ld_get_env_var(LD_LIBMAP); 705 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 706 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 707 ld_preload = ld_get_env_var(LD_PRELOAD); 708 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 709 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 710 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 711 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 712 if (library_path_rpath != NULL) { 713 if (library_path_rpath[0] == 'y' || 714 library_path_rpath[0] == 'Y' || 715 library_path_rpath[0] == '1') 716 ld_library_path_rpath = true; 717 else 718 ld_library_path_rpath = false; 719 } 720 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); 721 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { 722 sz = parse_integer(static_tls_extra); 723 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) 724 ld_static_tls_extra = sz; 725 } 726 dangerous_ld_env = libmap_disable || libmap_override != NULL || 727 ld_library_path != NULL || ld_preload != NULL || 728 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || 729 static_tls_extra != NULL; 730 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 731 ld_utrace = ld_get_env_var(LD_UTRACE); 732 733 set_ld_elf_hints_path(); 734 if (ld_debug != NULL && *ld_debug != '\0') 735 debug = 1; 736 dbg("%s is initialized, base address = %p", __progname, 737 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 738 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 739 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 740 741 dbg("initializing thread locks"); 742 lockdflt_init(); 743 744 /* 745 * Load the main program, or process its program header if it is 746 * already loaded. 747 */ 748 if (fd != -1) { /* Load the main program. */ 749 dbg("loading main program"); 750 obj_main = map_object(fd, argv0, NULL); 751 close(fd); 752 if (obj_main == NULL) 753 rtld_die(); 754 max_stack_flags = obj_main->stack_flags; 755 } else { /* Main program already loaded. */ 756 dbg("processing main program's program header"); 757 assert(aux_info[AT_PHDR] != NULL); 758 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 759 assert(aux_info[AT_PHNUM] != NULL); 760 phnum = aux_info[AT_PHNUM]->a_un.a_val; 761 assert(aux_info[AT_PHENT] != NULL); 762 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 763 assert(aux_info[AT_ENTRY] != NULL); 764 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 765 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 766 rtld_die(); 767 } 768 769 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 770 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 771 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 772 if (kexecpath[0] == '/') 773 obj_main->path = kexecpath; 774 else if (getcwd(buf, sizeof(buf)) == NULL || 775 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 776 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 777 obj_main->path = xstrdup(argv0); 778 else 779 obj_main->path = xstrdup(buf); 780 } else { 781 dbg("No AT_EXECPATH or direct exec"); 782 obj_main->path = xstrdup(argv0); 783 } 784 dbg("obj_main path %s", obj_main->path); 785 obj_main->mainprog = true; 786 787 if (aux_info[AT_STACKPROT] != NULL && 788 aux_info[AT_STACKPROT]->a_un.a_val != 0) 789 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 790 791 #ifndef COMPAT_libcompat 792 /* 793 * Get the actual dynamic linker pathname from the executable if 794 * possible. (It should always be possible.) That ensures that 795 * gdb will find the right dynamic linker even if a non-standard 796 * one is being used. 797 */ 798 if (obj_main->interp != NULL && 799 strcmp(obj_main->interp, obj_rtld.path) != 0) { 800 free(obj_rtld.path); 801 obj_rtld.path = xstrdup(obj_main->interp); 802 __progname = obj_rtld.path; 803 } 804 #endif 805 806 if (!digest_dynamic(obj_main, 0)) 807 rtld_die(); 808 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 809 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 810 obj_main->dynsymcount); 811 812 linkmap_add(obj_main); 813 linkmap_add(&obj_rtld); 814 815 /* Link the main program into the list of objects. */ 816 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 817 obj_count++; 818 obj_loads++; 819 820 /* Initialize a fake symbol for resolving undefined weak references. */ 821 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 822 sym_zero.st_shndx = SHN_UNDEF; 823 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 824 825 if (!libmap_disable) 826 libmap_disable = (bool)lm_init(libmap_override); 827 828 if (aux_info[AT_KPRELOAD] != NULL && 829 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 830 dbg("loading kernel vdso"); 831 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 832 rtld_die(); 833 } 834 835 dbg("loading LD_PRELOAD_FDS libraries"); 836 if (load_preload_objects(ld_preload_fds, true) == -1) 837 rtld_die(); 838 839 dbg("loading LD_PRELOAD libraries"); 840 if (load_preload_objects(ld_preload, false) == -1) 841 rtld_die(); 842 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 843 844 dbg("loading needed objects"); 845 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 846 0) == -1) 847 rtld_die(); 848 849 /* Make a list of all objects loaded at startup. */ 850 last_interposer = obj_main; 851 TAILQ_FOREACH(obj, &obj_list, next) { 852 if (obj->marker) 853 continue; 854 if (obj->z_interpose && obj != obj_main) { 855 objlist_put_after(&list_main, last_interposer, obj); 856 last_interposer = obj; 857 } else { 858 objlist_push_tail(&list_main, obj); 859 } 860 obj->refcount++; 861 } 862 863 dbg("checking for required versions"); 864 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 865 rtld_die(); 866 867 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 868 dump_auxv(aux_info); 869 870 if (ld_tracing) { /* We're done */ 871 trace_loaded_objects(obj_main, true); 872 exit(0); 873 } 874 875 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 876 dump_relocations(obj_main); 877 exit (0); 878 } 879 880 /* 881 * Processing tls relocations requires having the tls offsets 882 * initialized. Prepare offsets before starting initial 883 * relocation processing. 884 */ 885 dbg("initializing initial thread local storage offsets"); 886 STAILQ_FOREACH(entry, &list_main, link) { 887 /* 888 * Allocate all the initial objects out of the static TLS 889 * block even if they didn't ask for it. 890 */ 891 allocate_tls_offset(entry->obj); 892 } 893 894 if (relocate_objects(obj_main, 895 ld_bind_now != NULL && *ld_bind_now != '\0', 896 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 897 rtld_die(); 898 899 dbg("doing copy relocations"); 900 if (do_copy_relocations(obj_main) == -1) 901 rtld_die(); 902 903 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 904 dump_relocations(obj_main); 905 exit (0); 906 } 907 908 ifunc_init(aux); 909 910 /* 911 * Setup TLS for main thread. This must be done after the 912 * relocations are processed, since tls initialization section 913 * might be the subject for relocations. 914 */ 915 dbg("initializing initial thread local storage"); 916 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 917 918 dbg("initializing key program variables"); 919 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 920 set_program_var("environ", env); 921 set_program_var("__elf_aux_vector", aux); 922 923 /* Make a list of init functions to call. */ 924 objlist_init(&initlist); 925 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 926 preload_tail, &initlist); 927 928 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 929 930 map_stacks_exec(NULL); 931 932 if (!obj_main->crt_no_init) { 933 /* 934 * Make sure we don't call the main program's init and fini 935 * functions for binaries linked with old crt1 which calls 936 * _init itself. 937 */ 938 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 939 obj_main->preinit_array = obj_main->init_array = 940 obj_main->fini_array = (Elf_Addr)NULL; 941 } 942 943 if (direct_exec) { 944 /* Set osrel for direct-execed binary */ 945 mib[0] = CTL_KERN; 946 mib[1] = KERN_PROC; 947 mib[2] = KERN_PROC_OSREL; 948 mib[3] = getpid(); 949 osrel = obj_main->osrel; 950 sz = sizeof(old_osrel); 951 dbg("setting osrel to %d", osrel); 952 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 953 } 954 955 wlock_acquire(rtld_bind_lock, &lockstate); 956 957 dbg("resolving ifuncs"); 958 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 959 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 960 rtld_die(); 961 962 rtld_exit_ptr = rtld_exit; 963 if (obj_main->crt_no_init) 964 preinit_main(); 965 objlist_call_init(&initlist, &lockstate); 966 _r_debug_postinit(&obj_main->linkmap); 967 objlist_clear(&initlist); 968 dbg("loading filtees"); 969 TAILQ_FOREACH(obj, &obj_list, next) { 970 if (obj->marker) 971 continue; 972 if (ld_loadfltr || obj->z_loadfltr) 973 load_filtees(obj, 0, &lockstate); 974 } 975 976 dbg("enforcing main obj relro"); 977 if (obj_enforce_relro(obj_main) == -1) 978 rtld_die(); 979 980 lock_release(rtld_bind_lock, &lockstate); 981 982 dbg("transferring control to program entry point = %p", obj_main->entry); 983 984 /* Return the exit procedure and the program entry point. */ 985 *exit_proc = rtld_exit_ptr; 986 *objp = obj_main; 987 return ((func_ptr_type)obj_main->entry); 988 } 989 990 void * 991 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 992 { 993 void *ptr; 994 Elf_Addr target; 995 996 ptr = (void *)make_function_pointer(def, obj); 997 target = call_ifunc_resolver(ptr); 998 return ((void *)target); 999 } 1000 1001 Elf_Addr 1002 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1003 { 1004 const Elf_Rel *rel; 1005 const Elf_Sym *def; 1006 const Obj_Entry *defobj; 1007 Elf_Addr *where; 1008 Elf_Addr target; 1009 RtldLockState lockstate; 1010 1011 rlock_acquire(rtld_bind_lock, &lockstate); 1012 if (sigsetjmp(lockstate.env, 0) != 0) 1013 lock_upgrade(rtld_bind_lock, &lockstate); 1014 if (obj->pltrel) 1015 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1016 else 1017 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1018 1019 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1020 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1021 NULL, &lockstate); 1022 if (def == NULL) 1023 rtld_die(); 1024 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1025 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1026 else 1027 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1028 1029 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1030 defobj->strtab + def->st_name, 1031 obj->path == NULL ? NULL : basename(obj->path), 1032 (void *)target, 1033 defobj->path == NULL ? NULL : basename(defobj->path)); 1034 1035 /* 1036 * Write the new contents for the jmpslot. Note that depending on 1037 * architecture, the value which we need to return back to the 1038 * lazy binding trampoline may or may not be the target 1039 * address. The value returned from reloc_jmpslot() is the value 1040 * that the trampoline needs. 1041 */ 1042 target = reloc_jmpslot(where, target, defobj, obj, rel); 1043 lock_release(rtld_bind_lock, &lockstate); 1044 return (target); 1045 } 1046 1047 /* 1048 * Error reporting function. Use it like printf. If formats the message 1049 * into a buffer, and sets things up so that the next call to dlerror() 1050 * will return the message. 1051 */ 1052 void 1053 _rtld_error(const char *fmt, ...) 1054 { 1055 va_list ap; 1056 1057 va_start(ap, fmt); 1058 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1059 fmt, ap); 1060 va_end(ap); 1061 *lockinfo.dlerror_seen() = 0; 1062 dbg("rtld_error: %s", lockinfo.dlerror_loc()); 1063 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1064 } 1065 1066 /* 1067 * Return a dynamically-allocated copy of the current error message, if any. 1068 */ 1069 static struct dlerror_save * 1070 errmsg_save(void) 1071 { 1072 struct dlerror_save *res; 1073 1074 res = xmalloc(sizeof(*res)); 1075 res->seen = *lockinfo.dlerror_seen(); 1076 if (res->seen == 0) 1077 res->msg = xstrdup(lockinfo.dlerror_loc()); 1078 return (res); 1079 } 1080 1081 /* 1082 * Restore the current error message from a copy which was previously saved 1083 * by errmsg_save(). The copy is freed. 1084 */ 1085 static void 1086 errmsg_restore(struct dlerror_save *saved_msg) 1087 { 1088 if (saved_msg == NULL || saved_msg->seen == 1) { 1089 *lockinfo.dlerror_seen() = 1; 1090 } else { 1091 *lockinfo.dlerror_seen() = 0; 1092 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1093 lockinfo.dlerror_loc_sz); 1094 free(saved_msg->msg); 1095 } 1096 free(saved_msg); 1097 } 1098 1099 static const char * 1100 basename(const char *name) 1101 { 1102 const char *p; 1103 1104 p = strrchr(name, '/'); 1105 return (p != NULL ? p + 1 : name); 1106 } 1107 1108 static struct utsname uts; 1109 1110 static char * 1111 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1112 const char *subst, bool may_free) 1113 { 1114 char *p, *p1, *res, *resp; 1115 int subst_len, kw_len, subst_count, old_len, new_len; 1116 1117 kw_len = strlen(kw); 1118 1119 /* 1120 * First, count the number of the keyword occurrences, to 1121 * preallocate the final string. 1122 */ 1123 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1124 p1 = strstr(p, kw); 1125 if (p1 == NULL) 1126 break; 1127 } 1128 1129 /* 1130 * If the keyword is not found, just return. 1131 * 1132 * Return non-substituted string if resolution failed. We 1133 * cannot do anything more reasonable, the failure mode of the 1134 * caller is unresolved library anyway. 1135 */ 1136 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1137 return (may_free ? real : xstrdup(real)); 1138 if (obj != NULL) 1139 subst = obj->origin_path; 1140 1141 /* 1142 * There is indeed something to substitute. Calculate the 1143 * length of the resulting string, and allocate it. 1144 */ 1145 subst_len = strlen(subst); 1146 old_len = strlen(real); 1147 new_len = old_len + (subst_len - kw_len) * subst_count; 1148 res = xmalloc(new_len + 1); 1149 1150 /* 1151 * Now, execute the substitution loop. 1152 */ 1153 for (p = real, resp = res, *resp = '\0';;) { 1154 p1 = strstr(p, kw); 1155 if (p1 != NULL) { 1156 /* Copy the prefix before keyword. */ 1157 memcpy(resp, p, p1 - p); 1158 resp += p1 - p; 1159 /* Keyword replacement. */ 1160 memcpy(resp, subst, subst_len); 1161 resp += subst_len; 1162 *resp = '\0'; 1163 p = p1 + kw_len; 1164 } else 1165 break; 1166 } 1167 1168 /* Copy to the end of string and finish. */ 1169 strcat(resp, p); 1170 if (may_free) 1171 free(real); 1172 return (res); 1173 } 1174 1175 static const struct { 1176 const char *kw; 1177 bool pass_obj; 1178 const char *subst; 1179 } tokens[] = { 1180 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1181 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1182 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1183 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1184 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1185 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1186 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1187 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1188 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, 1189 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, 1190 }; 1191 1192 static char * 1193 origin_subst(Obj_Entry *obj, const char *real) 1194 { 1195 char *res; 1196 int i; 1197 1198 if (obj == NULL || !trust) 1199 return (xstrdup(real)); 1200 if (uts.sysname[0] == '\0') { 1201 if (uname(&uts) != 0) { 1202 _rtld_error("utsname failed: %d", errno); 1203 return (NULL); 1204 } 1205 } 1206 1207 /* __DECONST is safe here since without may_free real is unchanged */ 1208 res = __DECONST(char *, real); 1209 for (i = 0; i < (int)nitems(tokens); i++) { 1210 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1211 res, tokens[i].kw, tokens[i].subst, i != 0); 1212 } 1213 return (res); 1214 } 1215 1216 void 1217 rtld_die(void) 1218 { 1219 const char *msg = dlerror(); 1220 1221 if (msg == NULL) 1222 msg = "Fatal error"; 1223 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1224 rtld_fdputstr(STDERR_FILENO, msg); 1225 rtld_fdputchar(STDERR_FILENO, '\n'); 1226 _exit(1); 1227 } 1228 1229 /* 1230 * Process a shared object's DYNAMIC section, and save the important 1231 * information in its Obj_Entry structure. 1232 */ 1233 static void 1234 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1235 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1236 { 1237 const Elf_Dyn *dynp; 1238 Needed_Entry **needed_tail = &obj->needed; 1239 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1240 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1241 const Elf_Hashelt *hashtab; 1242 const Elf32_Word *hashval; 1243 Elf32_Word bkt, nmaskwords; 1244 int bloom_size32; 1245 int plttype = DT_REL; 1246 1247 *dyn_rpath = NULL; 1248 *dyn_soname = NULL; 1249 *dyn_runpath = NULL; 1250 1251 obj->bind_now = false; 1252 dynp = obj->dynamic; 1253 if (dynp == NULL) 1254 return; 1255 for (; dynp->d_tag != DT_NULL; dynp++) { 1256 switch (dynp->d_tag) { 1257 1258 case DT_REL: 1259 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1260 break; 1261 1262 case DT_RELSZ: 1263 obj->relsize = dynp->d_un.d_val; 1264 break; 1265 1266 case DT_RELENT: 1267 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1268 break; 1269 1270 case DT_JMPREL: 1271 obj->pltrel = (const Elf_Rel *) 1272 (obj->relocbase + dynp->d_un.d_ptr); 1273 break; 1274 1275 case DT_PLTRELSZ: 1276 obj->pltrelsize = dynp->d_un.d_val; 1277 break; 1278 1279 case DT_RELA: 1280 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1281 break; 1282 1283 case DT_RELASZ: 1284 obj->relasize = dynp->d_un.d_val; 1285 break; 1286 1287 case DT_RELAENT: 1288 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1289 break; 1290 1291 case DT_RELR: 1292 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1293 break; 1294 1295 case DT_RELRSZ: 1296 obj->relrsize = dynp->d_un.d_val; 1297 break; 1298 1299 case DT_RELRENT: 1300 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1301 break; 1302 1303 case DT_PLTREL: 1304 plttype = dynp->d_un.d_val; 1305 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1306 break; 1307 1308 case DT_SYMTAB: 1309 obj->symtab = (const Elf_Sym *) 1310 (obj->relocbase + dynp->d_un.d_ptr); 1311 break; 1312 1313 case DT_SYMENT: 1314 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1315 break; 1316 1317 case DT_STRTAB: 1318 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1319 break; 1320 1321 case DT_STRSZ: 1322 obj->strsize = dynp->d_un.d_val; 1323 break; 1324 1325 case DT_VERNEED: 1326 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1327 dynp->d_un.d_val); 1328 break; 1329 1330 case DT_VERNEEDNUM: 1331 obj->verneednum = dynp->d_un.d_val; 1332 break; 1333 1334 case DT_VERDEF: 1335 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1336 dynp->d_un.d_val); 1337 break; 1338 1339 case DT_VERDEFNUM: 1340 obj->verdefnum = dynp->d_un.d_val; 1341 break; 1342 1343 case DT_VERSYM: 1344 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1345 dynp->d_un.d_val); 1346 break; 1347 1348 case DT_HASH: 1349 { 1350 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1351 dynp->d_un.d_ptr); 1352 obj->nbuckets = hashtab[0]; 1353 obj->nchains = hashtab[1]; 1354 obj->buckets = hashtab + 2; 1355 obj->chains = obj->buckets + obj->nbuckets; 1356 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1357 obj->buckets != NULL; 1358 } 1359 break; 1360 1361 case DT_GNU_HASH: 1362 { 1363 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1364 dynp->d_un.d_ptr); 1365 obj->nbuckets_gnu = hashtab[0]; 1366 obj->symndx_gnu = hashtab[1]; 1367 nmaskwords = hashtab[2]; 1368 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1369 obj->maskwords_bm_gnu = nmaskwords - 1; 1370 obj->shift2_gnu = hashtab[3]; 1371 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1372 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1373 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1374 obj->symndx_gnu; 1375 /* Number of bitmask words is required to be power of 2 */ 1376 obj->valid_hash_gnu = powerof2(nmaskwords) && 1377 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1378 } 1379 break; 1380 1381 case DT_NEEDED: 1382 if (!obj->rtld) { 1383 Needed_Entry *nep = NEW(Needed_Entry); 1384 nep->name = dynp->d_un.d_val; 1385 nep->obj = NULL; 1386 nep->next = NULL; 1387 1388 *needed_tail = nep; 1389 needed_tail = &nep->next; 1390 } 1391 break; 1392 1393 case DT_FILTER: 1394 if (!obj->rtld) { 1395 Needed_Entry *nep = NEW(Needed_Entry); 1396 nep->name = dynp->d_un.d_val; 1397 nep->obj = NULL; 1398 nep->next = NULL; 1399 1400 *needed_filtees_tail = nep; 1401 needed_filtees_tail = &nep->next; 1402 1403 if (obj->linkmap.l_refname == NULL) 1404 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1405 } 1406 break; 1407 1408 case DT_AUXILIARY: 1409 if (!obj->rtld) { 1410 Needed_Entry *nep = NEW(Needed_Entry); 1411 nep->name = dynp->d_un.d_val; 1412 nep->obj = NULL; 1413 nep->next = NULL; 1414 1415 *needed_aux_filtees_tail = nep; 1416 needed_aux_filtees_tail = &nep->next; 1417 } 1418 break; 1419 1420 case DT_PLTGOT: 1421 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1422 break; 1423 1424 case DT_TEXTREL: 1425 obj->textrel = true; 1426 break; 1427 1428 case DT_SYMBOLIC: 1429 obj->symbolic = true; 1430 break; 1431 1432 case DT_RPATH: 1433 /* 1434 * We have to wait until later to process this, because we 1435 * might not have gotten the address of the string table yet. 1436 */ 1437 *dyn_rpath = dynp; 1438 break; 1439 1440 case DT_SONAME: 1441 *dyn_soname = dynp; 1442 break; 1443 1444 case DT_RUNPATH: 1445 *dyn_runpath = dynp; 1446 break; 1447 1448 case DT_INIT: 1449 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1450 break; 1451 1452 case DT_PREINIT_ARRAY: 1453 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1454 break; 1455 1456 case DT_PREINIT_ARRAYSZ: 1457 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1458 break; 1459 1460 case DT_INIT_ARRAY: 1461 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1462 break; 1463 1464 case DT_INIT_ARRAYSZ: 1465 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1466 break; 1467 1468 case DT_FINI: 1469 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1470 break; 1471 1472 case DT_FINI_ARRAY: 1473 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1474 break; 1475 1476 case DT_FINI_ARRAYSZ: 1477 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1478 break; 1479 1480 case DT_DEBUG: 1481 if (!early) 1482 dbg("Filling in DT_DEBUG entry"); 1483 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1484 break; 1485 1486 case DT_FLAGS: 1487 if (dynp->d_un.d_val & DF_ORIGIN) 1488 obj->z_origin = true; 1489 if (dynp->d_un.d_val & DF_SYMBOLIC) 1490 obj->symbolic = true; 1491 if (dynp->d_un.d_val & DF_TEXTREL) 1492 obj->textrel = true; 1493 if (dynp->d_un.d_val & DF_BIND_NOW) 1494 obj->bind_now = true; 1495 if (dynp->d_un.d_val & DF_STATIC_TLS) 1496 obj->static_tls = true; 1497 break; 1498 1499 #ifdef __powerpc__ 1500 #ifdef __powerpc64__ 1501 case DT_PPC64_GLINK: 1502 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1503 break; 1504 #else 1505 case DT_PPC_GOT: 1506 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1507 break; 1508 #endif 1509 #endif 1510 1511 case DT_FLAGS_1: 1512 if (dynp->d_un.d_val & DF_1_NOOPEN) 1513 obj->z_noopen = true; 1514 if (dynp->d_un.d_val & DF_1_ORIGIN) 1515 obj->z_origin = true; 1516 if (dynp->d_un.d_val & DF_1_GLOBAL) 1517 obj->z_global = true; 1518 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1519 obj->bind_now = true; 1520 if (dynp->d_un.d_val & DF_1_NODELETE) 1521 obj->z_nodelete = true; 1522 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1523 obj->z_loadfltr = true; 1524 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1525 obj->z_interpose = true; 1526 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1527 obj->z_nodeflib = true; 1528 if (dynp->d_un.d_val & DF_1_PIE) 1529 obj->z_pie = true; 1530 break; 1531 1532 default: 1533 if (!early) { 1534 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1535 (long)dynp->d_tag); 1536 } 1537 break; 1538 } 1539 } 1540 1541 obj->traced = false; 1542 1543 if (plttype == DT_RELA) { 1544 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1545 obj->pltrel = NULL; 1546 obj->pltrelasize = obj->pltrelsize; 1547 obj->pltrelsize = 0; 1548 } 1549 1550 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1551 if (obj->valid_hash_sysv) 1552 obj->dynsymcount = obj->nchains; 1553 else if (obj->valid_hash_gnu) { 1554 obj->dynsymcount = 0; 1555 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1556 if (obj->buckets_gnu[bkt] == 0) 1557 continue; 1558 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1559 do 1560 obj->dynsymcount++; 1561 while ((*hashval++ & 1u) == 0); 1562 } 1563 obj->dynsymcount += obj->symndx_gnu; 1564 } 1565 1566 if (obj->linkmap.l_refname != NULL) 1567 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1568 linkmap.l_refname; 1569 } 1570 1571 static bool 1572 obj_resolve_origin(Obj_Entry *obj) 1573 { 1574 1575 if (obj->origin_path != NULL) 1576 return (true); 1577 obj->origin_path = xmalloc(PATH_MAX); 1578 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1579 } 1580 1581 static bool 1582 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1583 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1584 { 1585 1586 if (obj->z_origin && !obj_resolve_origin(obj)) 1587 return (false); 1588 1589 if (dyn_runpath != NULL) { 1590 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1591 obj->runpath = origin_subst(obj, obj->runpath); 1592 } else if (dyn_rpath != NULL) { 1593 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1594 obj->rpath = origin_subst(obj, obj->rpath); 1595 } 1596 if (dyn_soname != NULL) 1597 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1598 return (true); 1599 } 1600 1601 static bool 1602 digest_dynamic(Obj_Entry *obj, int early) 1603 { 1604 const Elf_Dyn *dyn_rpath; 1605 const Elf_Dyn *dyn_soname; 1606 const Elf_Dyn *dyn_runpath; 1607 1608 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1609 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1610 } 1611 1612 /* 1613 * Process a shared object's program header. This is used only for the 1614 * main program, when the kernel has already loaded the main program 1615 * into memory before calling the dynamic linker. It creates and 1616 * returns an Obj_Entry structure. 1617 */ 1618 static Obj_Entry * 1619 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1620 { 1621 Obj_Entry *obj; 1622 const Elf_Phdr *phlimit = phdr + phnum; 1623 const Elf_Phdr *ph; 1624 Elf_Addr note_start, note_end; 1625 int nsegs = 0; 1626 1627 obj = obj_new(); 1628 for (ph = phdr; ph < phlimit; ph++) { 1629 if (ph->p_type != PT_PHDR) 1630 continue; 1631 1632 obj->phdr = phdr; 1633 obj->phsize = ph->p_memsz; 1634 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1635 break; 1636 } 1637 1638 obj->stack_flags = PF_X | PF_R | PF_W; 1639 1640 for (ph = phdr; ph < phlimit; ph++) { 1641 switch (ph->p_type) { 1642 1643 case PT_INTERP: 1644 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1645 break; 1646 1647 case PT_LOAD: 1648 if (nsegs == 0) { /* First load segment */ 1649 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); 1650 obj->mapbase = obj->vaddrbase + obj->relocbase; 1651 } else { /* Last load segment */ 1652 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - 1653 obj->vaddrbase; 1654 } 1655 nsegs++; 1656 break; 1657 1658 case PT_DYNAMIC: 1659 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1660 break; 1661 1662 case PT_TLS: 1663 obj->tlsindex = 1; 1664 obj->tlssize = ph->p_memsz; 1665 obj->tlsalign = ph->p_align; 1666 obj->tlsinitsize = ph->p_filesz; 1667 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1668 obj->tlspoffset = ph->p_offset; 1669 break; 1670 1671 case PT_GNU_STACK: 1672 obj->stack_flags = ph->p_flags; 1673 break; 1674 1675 case PT_GNU_RELRO: 1676 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 1677 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) - 1678 rtld_trunc_page(ph->p_vaddr); 1679 break; 1680 1681 case PT_NOTE: 1682 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1683 note_end = note_start + ph->p_filesz; 1684 digest_notes(obj, note_start, note_end); 1685 break; 1686 } 1687 } 1688 if (nsegs < 1) { 1689 _rtld_error("%s: too few PT_LOAD segments", path); 1690 return (NULL); 1691 } 1692 1693 obj->entry = entry; 1694 return (obj); 1695 } 1696 1697 void 1698 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1699 { 1700 const Elf_Note *note; 1701 const char *note_name; 1702 uintptr_t p; 1703 1704 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1705 note = (const Elf_Note *)((const char *)(note + 1) + 1706 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1707 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1708 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1709 note->n_descsz != sizeof(int32_t)) 1710 continue; 1711 if (note->n_type != NT_FREEBSD_ABI_TAG && 1712 note->n_type != NT_FREEBSD_FEATURE_CTL && 1713 note->n_type != NT_FREEBSD_NOINIT_TAG) 1714 continue; 1715 note_name = (const char *)(note + 1); 1716 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1717 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1718 continue; 1719 switch (note->n_type) { 1720 case NT_FREEBSD_ABI_TAG: 1721 /* FreeBSD osrel note */ 1722 p = (uintptr_t)(note + 1); 1723 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1724 obj->osrel = *(const int32_t *)(p); 1725 dbg("note osrel %d", obj->osrel); 1726 break; 1727 case NT_FREEBSD_FEATURE_CTL: 1728 /* FreeBSD ABI feature control note */ 1729 p = (uintptr_t)(note + 1); 1730 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1731 obj->fctl0 = *(const uint32_t *)(p); 1732 dbg("note fctl0 %#x", obj->fctl0); 1733 break; 1734 case NT_FREEBSD_NOINIT_TAG: 1735 /* FreeBSD 'crt does not call init' note */ 1736 obj->crt_no_init = true; 1737 dbg("note crt_no_init"); 1738 break; 1739 } 1740 } 1741 } 1742 1743 static Obj_Entry * 1744 dlcheck(void *handle) 1745 { 1746 Obj_Entry *obj; 1747 1748 TAILQ_FOREACH(obj, &obj_list, next) { 1749 if (obj == (Obj_Entry *) handle) 1750 break; 1751 } 1752 1753 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1754 _rtld_error("Invalid shared object handle %p", handle); 1755 return (NULL); 1756 } 1757 return (obj); 1758 } 1759 1760 /* 1761 * If the given object is already in the donelist, return true. Otherwise 1762 * add the object to the list and return false. 1763 */ 1764 static bool 1765 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1766 { 1767 unsigned int i; 1768 1769 for (i = 0; i < dlp->num_used; i++) 1770 if (dlp->objs[i] == obj) 1771 return (true); 1772 /* 1773 * Our donelist allocation should always be sufficient. But if 1774 * our threads locking isn't working properly, more shared objects 1775 * could have been loaded since we allocated the list. That should 1776 * never happen, but we'll handle it properly just in case it does. 1777 */ 1778 if (dlp->num_used < dlp->num_alloc) 1779 dlp->objs[dlp->num_used++] = obj; 1780 return (false); 1781 } 1782 1783 /* 1784 * SysV hash function for symbol table lookup. It is a slightly optimized 1785 * version of the hash specified by the System V ABI. 1786 */ 1787 Elf32_Word 1788 elf_hash(const char *name) 1789 { 1790 const unsigned char *p = (const unsigned char *)name; 1791 Elf32_Word h = 0; 1792 1793 while (*p != '\0') { 1794 h = (h << 4) + *p++; 1795 h ^= (h >> 24) & 0xf0; 1796 } 1797 return (h & 0x0fffffff); 1798 } 1799 1800 /* 1801 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1802 * unsigned in case it's implemented with a wider type. 1803 */ 1804 static uint32_t 1805 gnu_hash(const char *s) 1806 { 1807 uint32_t h; 1808 unsigned char c; 1809 1810 h = 5381; 1811 for (c = *s; c != '\0'; c = *++s) 1812 h = h * 33 + c; 1813 return (h & 0xffffffff); 1814 } 1815 1816 1817 /* 1818 * Find the library with the given name, and return its full pathname. 1819 * The returned string is dynamically allocated. Generates an error 1820 * message and returns NULL if the library cannot be found. 1821 * 1822 * If the second argument is non-NULL, then it refers to an already- 1823 * loaded shared object, whose library search path will be searched. 1824 * 1825 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1826 * descriptor (which is close-on-exec) will be passed out via the third 1827 * argument. 1828 * 1829 * The search order is: 1830 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1831 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1832 * LD_LIBRARY_PATH 1833 * DT_RUNPATH in the referencing file 1834 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1835 * from list) 1836 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1837 * 1838 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1839 */ 1840 static char * 1841 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1842 { 1843 char *pathname, *refobj_path; 1844 const char *name; 1845 bool nodeflib, objgiven; 1846 1847 objgiven = refobj != NULL; 1848 1849 if (libmap_disable || !objgiven || 1850 (name = lm_find(refobj->path, xname)) == NULL) 1851 name = xname; 1852 1853 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1854 if (name[0] != '/' && !trust) { 1855 _rtld_error("Absolute pathname required " 1856 "for shared object \"%s\"", name); 1857 return (NULL); 1858 } 1859 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1860 __DECONST(char *, name))); 1861 } 1862 1863 dbg(" Searching for \"%s\"", name); 1864 refobj_path = objgiven ? refobj->path : NULL; 1865 1866 /* 1867 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1868 * back to pre-conforming behaviour if user requested so with 1869 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1870 * nodeflib. 1871 */ 1872 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1873 pathname = search_library_path(name, ld_library_path, 1874 refobj_path, fdp); 1875 if (pathname != NULL) 1876 return (pathname); 1877 if (refobj != NULL) { 1878 pathname = search_library_path(name, refobj->rpath, 1879 refobj_path, fdp); 1880 if (pathname != NULL) 1881 return (pathname); 1882 } 1883 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1884 if (pathname != NULL) 1885 return (pathname); 1886 pathname = search_library_path(name, gethints(false), 1887 refobj_path, fdp); 1888 if (pathname != NULL) 1889 return (pathname); 1890 pathname = search_library_path(name, ld_standard_library_path, 1891 refobj_path, fdp); 1892 if (pathname != NULL) 1893 return (pathname); 1894 } else { 1895 nodeflib = objgiven ? refobj->z_nodeflib : false; 1896 if (objgiven) { 1897 pathname = search_library_path(name, refobj->rpath, 1898 refobj->path, fdp); 1899 if (pathname != NULL) 1900 return (pathname); 1901 } 1902 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1903 pathname = search_library_path(name, obj_main->rpath, 1904 refobj_path, fdp); 1905 if (pathname != NULL) 1906 return (pathname); 1907 } 1908 pathname = search_library_path(name, ld_library_path, 1909 refobj_path, fdp); 1910 if (pathname != NULL) 1911 return (pathname); 1912 if (objgiven) { 1913 pathname = search_library_path(name, refobj->runpath, 1914 refobj_path, fdp); 1915 if (pathname != NULL) 1916 return (pathname); 1917 } 1918 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1919 if (pathname != NULL) 1920 return (pathname); 1921 pathname = search_library_path(name, gethints(nodeflib), 1922 refobj_path, fdp); 1923 if (pathname != NULL) 1924 return (pathname); 1925 if (objgiven && !nodeflib) { 1926 pathname = search_library_path(name, 1927 ld_standard_library_path, refobj_path, fdp); 1928 if (pathname != NULL) 1929 return (pathname); 1930 } 1931 } 1932 1933 if (objgiven && refobj->path != NULL) { 1934 _rtld_error("Shared object \"%s\" not found, " 1935 "required by \"%s\"", name, basename(refobj->path)); 1936 } else { 1937 _rtld_error("Shared object \"%s\" not found", name); 1938 } 1939 return (NULL); 1940 } 1941 1942 /* 1943 * Given a symbol number in a referencing object, find the corresponding 1944 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1945 * no definition was found. Returns a pointer to the Obj_Entry of the 1946 * defining object via the reference parameter DEFOBJ_OUT. 1947 */ 1948 const Elf_Sym * 1949 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1950 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1951 RtldLockState *lockstate) 1952 { 1953 const Elf_Sym *ref; 1954 const Elf_Sym *def; 1955 const Obj_Entry *defobj; 1956 const Ver_Entry *ve; 1957 SymLook req; 1958 const char *name; 1959 int res; 1960 1961 /* 1962 * If we have already found this symbol, get the information from 1963 * the cache. 1964 */ 1965 if (symnum >= refobj->dynsymcount) 1966 return (NULL); /* Bad object */ 1967 if (cache != NULL && cache[symnum].sym != NULL) { 1968 *defobj_out = cache[symnum].obj; 1969 return (cache[symnum].sym); 1970 } 1971 1972 ref = refobj->symtab + symnum; 1973 name = refobj->strtab + ref->st_name; 1974 def = NULL; 1975 defobj = NULL; 1976 ve = NULL; 1977 1978 /* 1979 * We don't have to do a full scale lookup if the symbol is local. 1980 * We know it will bind to the instance in this load module; to 1981 * which we already have a pointer (ie ref). By not doing a lookup, 1982 * we not only improve performance, but it also avoids unresolvable 1983 * symbols when local symbols are not in the hash table. This has 1984 * been seen with the ia64 toolchain. 1985 */ 1986 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1987 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1988 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1989 symnum); 1990 } 1991 symlook_init(&req, name); 1992 req.flags = flags; 1993 ve = req.ventry = fetch_ventry(refobj, symnum); 1994 req.lockstate = lockstate; 1995 res = symlook_default(&req, refobj); 1996 if (res == 0) { 1997 def = req.sym_out; 1998 defobj = req.defobj_out; 1999 } 2000 } else { 2001 def = ref; 2002 defobj = refobj; 2003 } 2004 2005 /* 2006 * If we found no definition and the reference is weak, treat the 2007 * symbol as having the value zero. 2008 */ 2009 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2010 def = &sym_zero; 2011 defobj = obj_main; 2012 } 2013 2014 if (def != NULL) { 2015 *defobj_out = defobj; 2016 /* Record the information in the cache to avoid subsequent lookups. */ 2017 if (cache != NULL) { 2018 cache[symnum].sym = def; 2019 cache[symnum].obj = defobj; 2020 } 2021 } else { 2022 if (refobj != &obj_rtld) 2023 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2024 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2025 } 2026 return (def); 2027 } 2028 2029 /* Convert between native byte order and forced little resp. big endian. */ 2030 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) 2031 2032 /* 2033 * Return the search path from the ldconfig hints file, reading it if 2034 * necessary. If nostdlib is true, then the default search paths are 2035 * not added to result. 2036 * 2037 * Returns NULL if there are problems with the hints file, 2038 * or if the search path there is empty. 2039 */ 2040 static const char * 2041 gethints(bool nostdlib) 2042 { 2043 static char *filtered_path; 2044 static const char *hints; 2045 static struct elfhints_hdr hdr; 2046 struct fill_search_info_args sargs, hargs; 2047 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2048 struct dl_serpath *SLPpath, *hintpath; 2049 char *p; 2050 struct stat hint_stat; 2051 unsigned int SLPndx, hintndx, fndx, fcount; 2052 int fd; 2053 size_t flen; 2054 uint32_t dl; 2055 uint32_t magic; /* Magic number */ 2056 uint32_t version; /* File version (1) */ 2057 uint32_t strtab; /* Offset of string table in file */ 2058 uint32_t dirlist; /* Offset of directory list in string table */ 2059 uint32_t dirlistlen; /* strlen(dirlist) */ 2060 bool is_le; /* Does the hints file use little endian */ 2061 bool skip; 2062 2063 /* First call, read the hints file */ 2064 if (hints == NULL) { 2065 /* Keep from trying again in case the hints file is bad. */ 2066 hints = ""; 2067 2068 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { 2069 dbg("failed to open hints file \"%s\"", ld_elf_hints_path); 2070 return (NULL); 2071 } 2072 2073 /* 2074 * Check of hdr.dirlistlen value against type limit 2075 * intends to pacify static analyzers. Further 2076 * paranoia leads to checks that dirlist is fully 2077 * contained in the file range. 2078 */ 2079 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { 2080 dbg("failed to read %lu bytes from hints file \"%s\"", 2081 (u_long)sizeof hdr, ld_elf_hints_path); 2082 cleanup1: 2083 close(fd); 2084 hdr.dirlistlen = 0; 2085 return (NULL); 2086 } 2087 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); 2088 dbg("hints file byte-order: %s-endian", 2089 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big"); 2090 is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC); 2091 magic = COND_SWAP(hdr.magic); 2092 version = COND_SWAP(hdr.version); 2093 strtab = COND_SWAP(hdr.strtab); 2094 dirlist = COND_SWAP(hdr.dirlist); 2095 dirlistlen = COND_SWAP(hdr.dirlistlen); 2096 if (magic != ELFHINTS_MAGIC) { 2097 dbg("invalid magic number %#08x (expected: %#08x)", 2098 magic, ELFHINTS_MAGIC); 2099 goto cleanup1; 2100 } 2101 if (version != 1) { 2102 dbg("hints file version %d (expected: 1)", version); 2103 goto cleanup1; 2104 } 2105 if (dirlistlen > UINT_MAX / 2) { 2106 dbg("directory list is to long: %d > %d", 2107 dirlistlen, UINT_MAX / 2); 2108 goto cleanup1; 2109 } 2110 if (fstat(fd, &hint_stat) == -1) { 2111 dbg("failed to find length of hints file \"%s\"", 2112 ld_elf_hints_path); 2113 goto cleanup1; 2114 } 2115 dl = strtab; 2116 if (dl + dirlist < dl) { 2117 dbg("invalid string table position %d", dl); 2118 goto cleanup1; 2119 } 2120 dl += dirlist; 2121 if (dl + dirlistlen < dl) { 2122 dbg("invalid directory list offset %d", dirlist); 2123 goto cleanup1; 2124 } 2125 dl += dirlistlen; 2126 if (dl > hint_stat.st_size) { 2127 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", 2128 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); 2129 goto cleanup1; 2130 } 2131 p = xmalloc(dirlistlen + 1); 2132 if (pread(fd, p, dirlistlen + 1, 2133 strtab + dirlist) != (ssize_t)dirlistlen + 1 || 2134 p[dirlistlen] != '\0') { 2135 free(p); 2136 dbg("failed to read %d bytes starting at %d from hints file \"%s\"", 2137 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); 2138 goto cleanup1; 2139 } 2140 hints = p; 2141 close(fd); 2142 } 2143 2144 /* 2145 * If caller agreed to receive list which includes the default 2146 * paths, we are done. Otherwise, if we still did not 2147 * calculated filtered result, do it now. 2148 */ 2149 if (!nostdlib) 2150 return (hints[0] != '\0' ? hints : NULL); 2151 if (filtered_path != NULL) 2152 goto filt_ret; 2153 2154 /* 2155 * Obtain the list of all configured search paths, and the 2156 * list of the default paths. 2157 * 2158 * First estimate the size of the results. 2159 */ 2160 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2161 smeta.dls_cnt = 0; 2162 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2163 hmeta.dls_cnt = 0; 2164 2165 sargs.request = RTLD_DI_SERINFOSIZE; 2166 sargs.serinfo = &smeta; 2167 hargs.request = RTLD_DI_SERINFOSIZE; 2168 hargs.serinfo = &hmeta; 2169 2170 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2171 &sargs); 2172 path_enumerate(hints, fill_search_info, NULL, &hargs); 2173 2174 SLPinfo = xmalloc(smeta.dls_size); 2175 hintinfo = xmalloc(hmeta.dls_size); 2176 2177 /* 2178 * Next fetch both sets of paths. 2179 */ 2180 sargs.request = RTLD_DI_SERINFO; 2181 sargs.serinfo = SLPinfo; 2182 sargs.serpath = &SLPinfo->dls_serpath[0]; 2183 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2184 2185 hargs.request = RTLD_DI_SERINFO; 2186 hargs.serinfo = hintinfo; 2187 hargs.serpath = &hintinfo->dls_serpath[0]; 2188 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2189 2190 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2191 &sargs); 2192 path_enumerate(hints, fill_search_info, NULL, &hargs); 2193 2194 /* 2195 * Now calculate the difference between two sets, by excluding 2196 * standard paths from the full set. 2197 */ 2198 fndx = 0; 2199 fcount = 0; 2200 filtered_path = xmalloc(dirlistlen + 1); 2201 hintpath = &hintinfo->dls_serpath[0]; 2202 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2203 skip = false; 2204 SLPpath = &SLPinfo->dls_serpath[0]; 2205 /* 2206 * Check each standard path against current. 2207 */ 2208 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2209 /* matched, skip the path */ 2210 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2211 skip = true; 2212 break; 2213 } 2214 } 2215 if (skip) 2216 continue; 2217 /* 2218 * Not matched against any standard path, add the path 2219 * to result. Separate consequtive paths with ':'. 2220 */ 2221 if (fcount > 0) { 2222 filtered_path[fndx] = ':'; 2223 fndx++; 2224 } 2225 fcount++; 2226 flen = strlen(hintpath->dls_name); 2227 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2228 fndx += flen; 2229 } 2230 filtered_path[fndx] = '\0'; 2231 2232 free(SLPinfo); 2233 free(hintinfo); 2234 2235 filt_ret: 2236 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2237 } 2238 2239 static void 2240 init_dag(Obj_Entry *root) 2241 { 2242 const Needed_Entry *needed; 2243 const Objlist_Entry *elm; 2244 DoneList donelist; 2245 2246 if (root->dag_inited) 2247 return; 2248 donelist_init(&donelist); 2249 2250 /* Root object belongs to own DAG. */ 2251 objlist_push_tail(&root->dldags, root); 2252 objlist_push_tail(&root->dagmembers, root); 2253 donelist_check(&donelist, root); 2254 2255 /* 2256 * Add dependencies of root object to DAG in breadth order 2257 * by exploiting the fact that each new object get added 2258 * to the tail of the dagmembers list. 2259 */ 2260 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2261 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2262 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2263 continue; 2264 objlist_push_tail(&needed->obj->dldags, root); 2265 objlist_push_tail(&root->dagmembers, needed->obj); 2266 } 2267 } 2268 root->dag_inited = true; 2269 } 2270 2271 static void 2272 init_marker(Obj_Entry *marker) 2273 { 2274 2275 bzero(marker, sizeof(*marker)); 2276 marker->marker = true; 2277 } 2278 2279 Obj_Entry * 2280 globallist_curr(const Obj_Entry *obj) 2281 { 2282 2283 for (;;) { 2284 if (obj == NULL) 2285 return (NULL); 2286 if (!obj->marker) 2287 return (__DECONST(Obj_Entry *, obj)); 2288 obj = TAILQ_PREV(obj, obj_entry_q, next); 2289 } 2290 } 2291 2292 Obj_Entry * 2293 globallist_next(const Obj_Entry *obj) 2294 { 2295 2296 for (;;) { 2297 obj = TAILQ_NEXT(obj, next); 2298 if (obj == NULL) 2299 return (NULL); 2300 if (!obj->marker) 2301 return (__DECONST(Obj_Entry *, obj)); 2302 } 2303 } 2304 2305 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2306 static void 2307 hold_object(Obj_Entry *obj) 2308 { 2309 2310 obj->holdcount++; 2311 } 2312 2313 static void 2314 unhold_object(Obj_Entry *obj) 2315 { 2316 2317 assert(obj->holdcount > 0); 2318 if (--obj->holdcount == 0 && obj->unholdfree) 2319 release_object(obj); 2320 } 2321 2322 static void 2323 process_z(Obj_Entry *root) 2324 { 2325 const Objlist_Entry *elm; 2326 Obj_Entry *obj; 2327 2328 /* 2329 * Walk over object DAG and process every dependent object 2330 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2331 * to grow their own DAG. 2332 * 2333 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2334 * symlook_global() to work. 2335 * 2336 * For DF_1_NODELETE, the DAG should have its reference upped. 2337 */ 2338 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2339 obj = elm->obj; 2340 if (obj == NULL) 2341 continue; 2342 if (obj->z_nodelete && !obj->ref_nodel) { 2343 dbg("obj %s -z nodelete", obj->path); 2344 init_dag(obj); 2345 ref_dag(obj); 2346 obj->ref_nodel = true; 2347 } 2348 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2349 dbg("obj %s -z global", obj->path); 2350 objlist_push_tail(&list_global, obj); 2351 init_dag(obj); 2352 } 2353 } 2354 } 2355 2356 static void 2357 parse_rtld_phdr(Obj_Entry *obj) 2358 { 2359 const Elf_Phdr *ph; 2360 Elf_Addr note_start, note_end; 2361 2362 obj->stack_flags = PF_X | PF_R | PF_W; 2363 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2364 obj->phsize; ph++) { 2365 switch (ph->p_type) { 2366 case PT_GNU_STACK: 2367 obj->stack_flags = ph->p_flags; 2368 break; 2369 case PT_GNU_RELRO: 2370 obj->relro_page = obj->relocbase + 2371 rtld_trunc_page(ph->p_vaddr); 2372 obj->relro_size = rtld_round_page(ph->p_memsz); 2373 break; 2374 case PT_NOTE: 2375 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2376 note_end = note_start + ph->p_filesz; 2377 digest_notes(obj, note_start, note_end); 2378 break; 2379 } 2380 } 2381 } 2382 2383 /* 2384 * Initialize the dynamic linker. The argument is the address at which 2385 * the dynamic linker has been mapped into memory. The primary task of 2386 * this function is to relocate the dynamic linker. 2387 */ 2388 static void 2389 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2390 { 2391 Obj_Entry objtmp; /* Temporary rtld object */ 2392 const Elf_Ehdr *ehdr; 2393 const Elf_Dyn *dyn_rpath; 2394 const Elf_Dyn *dyn_soname; 2395 const Elf_Dyn *dyn_runpath; 2396 2397 #ifdef RTLD_INIT_PAGESIZES_EARLY 2398 /* The page size is required by the dynamic memory allocator. */ 2399 init_pagesizes(aux_info); 2400 #endif 2401 2402 /* 2403 * Conjure up an Obj_Entry structure for the dynamic linker. 2404 * 2405 * The "path" member can't be initialized yet because string constants 2406 * cannot yet be accessed. Below we will set it correctly. 2407 */ 2408 memset(&objtmp, 0, sizeof(objtmp)); 2409 objtmp.path = NULL; 2410 objtmp.rtld = true; 2411 objtmp.mapbase = mapbase; 2412 #ifdef PIC 2413 objtmp.relocbase = mapbase; 2414 #endif 2415 2416 objtmp.dynamic = rtld_dynamic(&objtmp); 2417 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2418 assert(objtmp.needed == NULL); 2419 assert(!objtmp.textrel); 2420 /* 2421 * Temporarily put the dynamic linker entry into the object list, so 2422 * that symbols can be found. 2423 */ 2424 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2425 2426 ehdr = (Elf_Ehdr *)mapbase; 2427 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2428 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2429 2430 /* Initialize the object list. */ 2431 TAILQ_INIT(&obj_list); 2432 2433 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2434 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2435 2436 #ifndef RTLD_INIT_PAGESIZES_EARLY 2437 /* The page size is required by the dynamic memory allocator. */ 2438 init_pagesizes(aux_info); 2439 #endif 2440 2441 if (aux_info[AT_OSRELDATE] != NULL) 2442 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2443 2444 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2445 2446 /* Replace the path with a dynamically allocated copy. */ 2447 obj_rtld.path = xstrdup(ld_path_rtld); 2448 2449 parse_rtld_phdr(&obj_rtld); 2450 if (obj_enforce_relro(&obj_rtld) == -1) 2451 rtld_die(); 2452 2453 r_debug.r_version = R_DEBUG_VERSION; 2454 r_debug.r_brk = r_debug_state; 2455 r_debug.r_state = RT_CONSISTENT; 2456 r_debug.r_ldbase = obj_rtld.relocbase; 2457 } 2458 2459 /* 2460 * Retrieve the array of supported page sizes. The kernel provides the page 2461 * sizes in increasing order. 2462 */ 2463 static void 2464 init_pagesizes(Elf_Auxinfo **aux_info) 2465 { 2466 static size_t psa[MAXPAGESIZES]; 2467 int mib[2]; 2468 size_t len, size; 2469 2470 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2471 NULL) { 2472 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2473 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2474 } else { 2475 len = 2; 2476 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2477 size = sizeof(psa); 2478 else { 2479 /* As a fallback, retrieve the base page size. */ 2480 size = sizeof(psa[0]); 2481 if (aux_info[AT_PAGESZ] != NULL) { 2482 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2483 goto psa_filled; 2484 } else { 2485 mib[0] = CTL_HW; 2486 mib[1] = HW_PAGESIZE; 2487 len = 2; 2488 } 2489 } 2490 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2491 _rtld_error("sysctl for hw.pagesize(s) failed"); 2492 rtld_die(); 2493 } 2494 psa_filled: 2495 pagesizes = psa; 2496 } 2497 npagesizes = size / sizeof(pagesizes[0]); 2498 /* Discard any invalid entries at the end of the array. */ 2499 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2500 npagesizes--; 2501 2502 page_size = pagesizes[0]; 2503 } 2504 2505 /* 2506 * Add the init functions from a needed object list (and its recursive 2507 * needed objects) to "list". This is not used directly; it is a helper 2508 * function for initlist_add_objects(). The write lock must be held 2509 * when this function is called. 2510 */ 2511 static void 2512 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2513 { 2514 /* Recursively process the successor needed objects. */ 2515 if (needed->next != NULL) 2516 initlist_add_neededs(needed->next, list); 2517 2518 /* Process the current needed object. */ 2519 if (needed->obj != NULL) 2520 initlist_add_objects(needed->obj, needed->obj, list); 2521 } 2522 2523 /* 2524 * Scan all of the DAGs rooted in the range of objects from "obj" to 2525 * "tail" and add their init functions to "list". This recurses over 2526 * the DAGs and ensure the proper init ordering such that each object's 2527 * needed libraries are initialized before the object itself. At the 2528 * same time, this function adds the objects to the global finalization 2529 * list "list_fini" in the opposite order. The write lock must be 2530 * held when this function is called. 2531 */ 2532 static void 2533 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2534 { 2535 Obj_Entry *nobj; 2536 2537 if (obj->init_scanned || obj->init_done) 2538 return; 2539 obj->init_scanned = true; 2540 2541 /* Recursively process the successor objects. */ 2542 nobj = globallist_next(obj); 2543 if (nobj != NULL && obj != tail) 2544 initlist_add_objects(nobj, tail, list); 2545 2546 /* Recursively process the needed objects. */ 2547 if (obj->needed != NULL) 2548 initlist_add_neededs(obj->needed, list); 2549 if (obj->needed_filtees != NULL) 2550 initlist_add_neededs(obj->needed_filtees, list); 2551 if (obj->needed_aux_filtees != NULL) 2552 initlist_add_neededs(obj->needed_aux_filtees, list); 2553 2554 /* Add the object to the init list. */ 2555 objlist_push_tail(list, obj); 2556 2557 /* Add the object to the global fini list in the reverse order. */ 2558 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2559 && !obj->on_fini_list) { 2560 objlist_push_head(&list_fini, obj); 2561 obj->on_fini_list = true; 2562 } 2563 } 2564 2565 static void 2566 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2567 { 2568 Needed_Entry *needed, *needed1; 2569 2570 for (needed = n; needed != NULL; needed = needed->next) { 2571 if (needed->obj != NULL) { 2572 dlclose_locked(needed->obj, lockstate); 2573 needed->obj = NULL; 2574 } 2575 } 2576 for (needed = n; needed != NULL; needed = needed1) { 2577 needed1 = needed->next; 2578 free(needed); 2579 } 2580 } 2581 2582 static void 2583 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2584 { 2585 2586 free_needed_filtees(obj->needed_filtees, lockstate); 2587 obj->needed_filtees = NULL; 2588 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2589 obj->needed_aux_filtees = NULL; 2590 obj->filtees_loaded = false; 2591 } 2592 2593 static void 2594 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2595 RtldLockState *lockstate) 2596 { 2597 2598 for (; needed != NULL; needed = needed->next) { 2599 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2600 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2601 RTLD_LOCAL, lockstate); 2602 } 2603 } 2604 2605 static void 2606 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2607 { 2608 if (obj->filtees_loaded || obj->filtees_loading) 2609 return; 2610 lock_restart_for_upgrade(lockstate); 2611 obj->filtees_loading = true; 2612 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2613 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2614 obj->filtees_loaded = true; 2615 obj->filtees_loading = false; 2616 } 2617 2618 static int 2619 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2620 { 2621 Obj_Entry *obj1; 2622 2623 for (; needed != NULL; needed = needed->next) { 2624 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2625 flags & ~RTLD_LO_NOLOAD); 2626 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2627 return (-1); 2628 } 2629 return (0); 2630 } 2631 2632 /* 2633 * Given a shared object, traverse its list of needed objects, and load 2634 * each of them. Returns 0 on success. Generates an error message and 2635 * returns -1 on failure. 2636 */ 2637 static int 2638 load_needed_objects(Obj_Entry *first, int flags) 2639 { 2640 Obj_Entry *obj; 2641 2642 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2643 if (obj->marker) 2644 continue; 2645 if (process_needed(obj, obj->needed, flags) == -1) 2646 return (-1); 2647 } 2648 return (0); 2649 } 2650 2651 static int 2652 load_preload_objects(const char *penv, bool isfd) 2653 { 2654 Obj_Entry *obj; 2655 const char *name; 2656 size_t len; 2657 char savech, *p, *psave; 2658 int fd; 2659 static const char delim[] = " \t:;"; 2660 2661 if (penv == NULL) 2662 return (0); 2663 2664 p = psave = xstrdup(penv); 2665 p += strspn(p, delim); 2666 while (*p != '\0') { 2667 len = strcspn(p, delim); 2668 2669 savech = p[len]; 2670 p[len] = '\0'; 2671 if (isfd) { 2672 name = NULL; 2673 fd = parse_integer(p); 2674 if (fd == -1) { 2675 free(psave); 2676 return (-1); 2677 } 2678 } else { 2679 name = p; 2680 fd = -1; 2681 } 2682 2683 obj = load_object(name, fd, NULL, 0); 2684 if (obj == NULL) { 2685 free(psave); 2686 return (-1); /* XXX - cleanup */ 2687 } 2688 obj->z_interpose = true; 2689 p[len] = savech; 2690 p += len; 2691 p += strspn(p, delim); 2692 } 2693 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2694 2695 free(psave); 2696 return (0); 2697 } 2698 2699 static const char * 2700 printable_path(const char *path) 2701 { 2702 2703 return (path == NULL ? "<unknown>" : path); 2704 } 2705 2706 /* 2707 * Load a shared object into memory, if it is not already loaded. The 2708 * object may be specified by name or by user-supplied file descriptor 2709 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2710 * duplicate is. 2711 * 2712 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2713 * on failure. 2714 */ 2715 static Obj_Entry * 2716 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2717 { 2718 Obj_Entry *obj; 2719 int fd; 2720 struct stat sb; 2721 char *path; 2722 2723 fd = -1; 2724 if (name != NULL) { 2725 TAILQ_FOREACH(obj, &obj_list, next) { 2726 if (obj->marker || obj->doomed) 2727 continue; 2728 if (object_match_name(obj, name)) 2729 return (obj); 2730 } 2731 2732 path = find_library(name, refobj, &fd); 2733 if (path == NULL) 2734 return (NULL); 2735 } else 2736 path = NULL; 2737 2738 if (fd >= 0) { 2739 /* 2740 * search_library_pathfds() opens a fresh file descriptor for the 2741 * library, so there is no need to dup(). 2742 */ 2743 } else if (fd_u == -1) { 2744 /* 2745 * If we didn't find a match by pathname, or the name is not 2746 * supplied, open the file and check again by device and inode. 2747 * This avoids false mismatches caused by multiple links or ".." 2748 * in pathnames. 2749 * 2750 * To avoid a race, we open the file and use fstat() rather than 2751 * using stat(). 2752 */ 2753 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2754 _rtld_error("Cannot open \"%s\"", path); 2755 free(path); 2756 return (NULL); 2757 } 2758 } else { 2759 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2760 if (fd == -1) { 2761 _rtld_error("Cannot dup fd"); 2762 free(path); 2763 return (NULL); 2764 } 2765 } 2766 if (fstat(fd, &sb) == -1) { 2767 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2768 close(fd); 2769 free(path); 2770 return (NULL); 2771 } 2772 TAILQ_FOREACH(obj, &obj_list, next) { 2773 if (obj->marker || obj->doomed) 2774 continue; 2775 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2776 break; 2777 } 2778 if (obj != NULL) { 2779 if (name != NULL) 2780 object_add_name(obj, name); 2781 free(path); 2782 close(fd); 2783 return (obj); 2784 } 2785 if (flags & RTLD_LO_NOLOAD) { 2786 free(path); 2787 close(fd); 2788 return (NULL); 2789 } 2790 2791 /* First use of this object, so we must map it in */ 2792 obj = do_load_object(fd, name, path, &sb, flags); 2793 if (obj == NULL) 2794 free(path); 2795 close(fd); 2796 2797 return (obj); 2798 } 2799 2800 static Obj_Entry * 2801 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2802 int flags) 2803 { 2804 Obj_Entry *obj; 2805 struct statfs fs; 2806 2807 /* 2808 * First, make sure that environment variables haven't been 2809 * used to circumvent the noexec flag on a filesystem. 2810 * We ignore fstatfs(2) failures, since fd might reference 2811 * not a file, e.g. shmfd. 2812 */ 2813 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2814 (fs.f_flags & MNT_NOEXEC) != 0) { 2815 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2816 return (NULL); 2817 } 2818 2819 dbg("loading \"%s\"", printable_path(path)); 2820 obj = map_object(fd, printable_path(path), sbp); 2821 if (obj == NULL) 2822 return (NULL); 2823 2824 /* 2825 * If DT_SONAME is present in the object, digest_dynamic2 already 2826 * added it to the object names. 2827 */ 2828 if (name != NULL) 2829 object_add_name(obj, name); 2830 obj->path = path; 2831 if (!digest_dynamic(obj, 0)) 2832 goto errp; 2833 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2834 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2835 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2836 dbg("refusing to load PIE executable \"%s\"", obj->path); 2837 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2838 goto errp; 2839 } 2840 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2841 RTLD_LO_DLOPEN) { 2842 dbg("refusing to load non-loadable \"%s\"", obj->path); 2843 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2844 goto errp; 2845 } 2846 2847 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2848 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2849 obj_count++; 2850 obj_loads++; 2851 linkmap_add(obj); /* for GDB & dlinfo() */ 2852 max_stack_flags |= obj->stack_flags; 2853 2854 dbg(" %p .. %p: %s", obj->mapbase, 2855 obj->mapbase + obj->mapsize - 1, obj->path); 2856 if (obj->textrel) 2857 dbg(" WARNING: %s has impure text", obj->path); 2858 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2859 obj->path); 2860 2861 return (obj); 2862 2863 errp: 2864 munmap(obj->mapbase, obj->mapsize); 2865 obj_free(obj); 2866 return (NULL); 2867 } 2868 2869 static int 2870 load_kpreload(const void *addr) 2871 { 2872 Obj_Entry *obj; 2873 const Elf_Ehdr *ehdr; 2874 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2875 static const char kname[] = "[vdso]"; 2876 2877 ehdr = addr; 2878 if (!check_elf_headers(ehdr, "kpreload")) 2879 return (-1); 2880 obj = obj_new(); 2881 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2882 obj->phdr = phdr; 2883 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2884 phlimit = phdr + ehdr->e_phnum; 2885 seg0 = segn = NULL; 2886 2887 for (; phdr < phlimit; phdr++) { 2888 switch (phdr->p_type) { 2889 case PT_DYNAMIC: 2890 phdyn = phdr; 2891 break; 2892 case PT_GNU_STACK: 2893 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2894 obj->stack_flags = phdr->p_flags; 2895 break; 2896 case PT_LOAD: 2897 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2898 seg0 = phdr; 2899 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2900 phdr->p_vaddr + phdr->p_memsz) 2901 segn = phdr; 2902 break; 2903 } 2904 } 2905 2906 obj->mapbase = __DECONST(caddr_t, addr); 2907 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2908 obj->vaddrbase = 0; 2909 obj->relocbase = obj->mapbase; 2910 2911 object_add_name(obj, kname); 2912 obj->path = xstrdup(kname); 2913 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2914 2915 if (!digest_dynamic(obj, 0)) { 2916 obj_free(obj); 2917 return (-1); 2918 } 2919 2920 /* 2921 * We assume that kernel-preloaded object does not need 2922 * relocation. It is currently written into read-only page, 2923 * handling relocations would mean we need to allocate at 2924 * least one additional page per AS. 2925 */ 2926 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2927 obj->path, obj->mapbase, obj->phdr, seg0, 2928 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2929 2930 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2931 obj_count++; 2932 obj_loads++; 2933 linkmap_add(obj); /* for GDB & dlinfo() */ 2934 max_stack_flags |= obj->stack_flags; 2935 2936 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2937 return (0); 2938 } 2939 2940 Obj_Entry * 2941 obj_from_addr(const void *addr) 2942 { 2943 Obj_Entry *obj; 2944 2945 TAILQ_FOREACH(obj, &obj_list, next) { 2946 if (obj->marker) 2947 continue; 2948 if (addr < (void *) obj->mapbase) 2949 continue; 2950 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2951 return obj; 2952 } 2953 return (NULL); 2954 } 2955 2956 static void 2957 preinit_main(void) 2958 { 2959 Elf_Addr *preinit_addr; 2960 int index; 2961 2962 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2963 if (preinit_addr == NULL) 2964 return; 2965 2966 for (index = 0; index < obj_main->preinit_array_num; index++) { 2967 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2968 dbg("calling preinit function for %s at %p", obj_main->path, 2969 (void *)preinit_addr[index]); 2970 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2971 0, 0, obj_main->path); 2972 call_init_pointer(obj_main, preinit_addr[index]); 2973 } 2974 } 2975 } 2976 2977 /* 2978 * Call the finalization functions for each of the objects in "list" 2979 * belonging to the DAG of "root" and referenced once. If NULL "root" 2980 * is specified, every finalization function will be called regardless 2981 * of the reference count and the list elements won't be freed. All of 2982 * the objects are expected to have non-NULL fini functions. 2983 */ 2984 static void 2985 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2986 { 2987 Objlist_Entry *elm; 2988 struct dlerror_save *saved_msg; 2989 Elf_Addr *fini_addr; 2990 int index; 2991 2992 assert(root == NULL || root->refcount == 1); 2993 2994 if (root != NULL) 2995 root->doomed = true; 2996 2997 /* 2998 * Preserve the current error message since a fini function might 2999 * call into the dynamic linker and overwrite it. 3000 */ 3001 saved_msg = errmsg_save(); 3002 do { 3003 STAILQ_FOREACH(elm, list, link) { 3004 if (root != NULL && (elm->obj->refcount != 1 || 3005 objlist_find(&root->dagmembers, elm->obj) == NULL)) 3006 continue; 3007 /* Remove object from fini list to prevent recursive invocation. */ 3008 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3009 /* Ensure that new references cannot be acquired. */ 3010 elm->obj->doomed = true; 3011 3012 hold_object(elm->obj); 3013 lock_release(rtld_bind_lock, lockstate); 3014 /* 3015 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3016 * When this happens, DT_FINI_ARRAY is processed first. 3017 */ 3018 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3019 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3020 for (index = elm->obj->fini_array_num - 1; index >= 0; 3021 index--) { 3022 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3023 dbg("calling fini function for %s at %p", 3024 elm->obj->path, (void *)fini_addr[index]); 3025 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3026 (void *)fini_addr[index], 0, 0, elm->obj->path); 3027 call_initfini_pointer(elm->obj, fini_addr[index]); 3028 } 3029 } 3030 } 3031 if (elm->obj->fini != (Elf_Addr)NULL) { 3032 dbg("calling fini function for %s at %p", elm->obj->path, 3033 (void *)elm->obj->fini); 3034 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3035 0, 0, elm->obj->path); 3036 call_initfini_pointer(elm->obj, elm->obj->fini); 3037 } 3038 wlock_acquire(rtld_bind_lock, lockstate); 3039 unhold_object(elm->obj); 3040 /* No need to free anything if process is going down. */ 3041 if (root != NULL) 3042 free(elm); 3043 /* 3044 * We must restart the list traversal after every fini call 3045 * because a dlclose() call from the fini function or from 3046 * another thread might have modified the reference counts. 3047 */ 3048 break; 3049 } 3050 } while (elm != NULL); 3051 errmsg_restore(saved_msg); 3052 } 3053 3054 /* 3055 * Call the initialization functions for each of the objects in 3056 * "list". All of the objects are expected to have non-NULL init 3057 * functions. 3058 */ 3059 static void 3060 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3061 { 3062 Objlist_Entry *elm; 3063 Obj_Entry *obj; 3064 struct dlerror_save *saved_msg; 3065 Elf_Addr *init_addr; 3066 void (*reg)(void (*)(void)); 3067 int index; 3068 3069 /* 3070 * Clean init_scanned flag so that objects can be rechecked and 3071 * possibly initialized earlier if any of vectors called below 3072 * cause the change by using dlopen. 3073 */ 3074 TAILQ_FOREACH(obj, &obj_list, next) { 3075 if (obj->marker) 3076 continue; 3077 obj->init_scanned = false; 3078 } 3079 3080 /* 3081 * Preserve the current error message since an init function might 3082 * call into the dynamic linker and overwrite it. 3083 */ 3084 saved_msg = errmsg_save(); 3085 STAILQ_FOREACH(elm, list, link) { 3086 if (elm->obj->init_done) /* Initialized early. */ 3087 continue; 3088 /* 3089 * Race: other thread might try to use this object before current 3090 * one completes the initialization. Not much can be done here 3091 * without better locking. 3092 */ 3093 elm->obj->init_done = true; 3094 hold_object(elm->obj); 3095 reg = NULL; 3096 if (elm->obj == obj_main && obj_main->crt_no_init) { 3097 reg = (void (*)(void (*)(void)))get_program_var_addr( 3098 "__libc_atexit", lockstate); 3099 } 3100 lock_release(rtld_bind_lock, lockstate); 3101 if (reg != NULL) { 3102 reg(rtld_exit); 3103 rtld_exit_ptr = rtld_nop_exit; 3104 } 3105 3106 /* 3107 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3108 * When this happens, DT_INIT is processed first. 3109 */ 3110 if (elm->obj->init != (Elf_Addr)NULL) { 3111 dbg("calling init function for %s at %p", elm->obj->path, 3112 (void *)elm->obj->init); 3113 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3114 0, 0, elm->obj->path); 3115 call_init_pointer(elm->obj, elm->obj->init); 3116 } 3117 init_addr = (Elf_Addr *)elm->obj->init_array; 3118 if (init_addr != NULL) { 3119 for (index = 0; index < elm->obj->init_array_num; index++) { 3120 if (init_addr[index] != 0 && init_addr[index] != 1) { 3121 dbg("calling init function for %s at %p", elm->obj->path, 3122 (void *)init_addr[index]); 3123 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3124 (void *)init_addr[index], 0, 0, elm->obj->path); 3125 call_init_pointer(elm->obj, init_addr[index]); 3126 } 3127 } 3128 } 3129 wlock_acquire(rtld_bind_lock, lockstate); 3130 unhold_object(elm->obj); 3131 } 3132 errmsg_restore(saved_msg); 3133 } 3134 3135 static void 3136 objlist_clear(Objlist *list) 3137 { 3138 Objlist_Entry *elm; 3139 3140 while (!STAILQ_EMPTY(list)) { 3141 elm = STAILQ_FIRST(list); 3142 STAILQ_REMOVE_HEAD(list, link); 3143 free(elm); 3144 } 3145 } 3146 3147 static Objlist_Entry * 3148 objlist_find(Objlist *list, const Obj_Entry *obj) 3149 { 3150 Objlist_Entry *elm; 3151 3152 STAILQ_FOREACH(elm, list, link) 3153 if (elm->obj == obj) 3154 return elm; 3155 return (NULL); 3156 } 3157 3158 static void 3159 objlist_init(Objlist *list) 3160 { 3161 STAILQ_INIT(list); 3162 } 3163 3164 static void 3165 objlist_push_head(Objlist *list, Obj_Entry *obj) 3166 { 3167 Objlist_Entry *elm; 3168 3169 elm = NEW(Objlist_Entry); 3170 elm->obj = obj; 3171 STAILQ_INSERT_HEAD(list, elm, link); 3172 } 3173 3174 static void 3175 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3176 { 3177 Objlist_Entry *elm; 3178 3179 elm = NEW(Objlist_Entry); 3180 elm->obj = obj; 3181 STAILQ_INSERT_TAIL(list, elm, link); 3182 } 3183 3184 static void 3185 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3186 { 3187 Objlist_Entry *elm, *listelm; 3188 3189 STAILQ_FOREACH(listelm, list, link) { 3190 if (listelm->obj == listobj) 3191 break; 3192 } 3193 elm = NEW(Objlist_Entry); 3194 elm->obj = obj; 3195 if (listelm != NULL) 3196 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3197 else 3198 STAILQ_INSERT_TAIL(list, elm, link); 3199 } 3200 3201 static void 3202 objlist_remove(Objlist *list, Obj_Entry *obj) 3203 { 3204 Objlist_Entry *elm; 3205 3206 if ((elm = objlist_find(list, obj)) != NULL) { 3207 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3208 free(elm); 3209 } 3210 } 3211 3212 /* 3213 * Relocate dag rooted in the specified object. 3214 * Returns 0 on success, or -1 on failure. 3215 */ 3216 3217 static int 3218 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3219 int flags, RtldLockState *lockstate) 3220 { 3221 Objlist_Entry *elm; 3222 int error; 3223 3224 error = 0; 3225 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3226 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3227 lockstate); 3228 if (error == -1) 3229 break; 3230 } 3231 return (error); 3232 } 3233 3234 /* 3235 * Prepare for, or clean after, relocating an object marked with 3236 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3237 * segments are remapped read-write. After relocations are done, the 3238 * segment's permissions are returned back to the modes specified in 3239 * the phdrs. If any relocation happened, or always for wired 3240 * program, COW is triggered. 3241 */ 3242 static int 3243 reloc_textrel_prot(Obj_Entry *obj, bool before) 3244 { 3245 const Elf_Phdr *ph; 3246 void *base; 3247 size_t l, sz; 3248 int prot; 3249 3250 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3251 l--, ph++) { 3252 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3253 continue; 3254 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3255 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3256 rtld_trunc_page(ph->p_vaddr); 3257 prot = before ? (PROT_READ | PROT_WRITE) : 3258 convert_prot(ph->p_flags); 3259 if (mprotect(base, sz, prot) == -1) { 3260 _rtld_error("%s: Cannot write-%sable text segment: %s", 3261 obj->path, before ? "en" : "dis", 3262 rtld_strerror(errno)); 3263 return (-1); 3264 } 3265 } 3266 return (0); 3267 } 3268 3269 /* Process RELR relative relocations. */ 3270 static void 3271 reloc_relr(Obj_Entry *obj) 3272 { 3273 const Elf_Relr *relr, *relrlim; 3274 Elf_Addr *where; 3275 3276 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3277 for (relr = obj->relr; relr < relrlim; relr++) { 3278 Elf_Relr entry = *relr; 3279 3280 if ((entry & 1) == 0) { 3281 where = (Elf_Addr *)(obj->relocbase + entry); 3282 *where++ += (Elf_Addr)obj->relocbase; 3283 } else { 3284 for (long i = 0; (entry >>= 1) != 0; i++) 3285 if ((entry & 1) != 0) 3286 where[i] += (Elf_Addr)obj->relocbase; 3287 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3288 } 3289 } 3290 } 3291 3292 /* 3293 * Relocate single object. 3294 * Returns 0 on success, or -1 on failure. 3295 */ 3296 static int 3297 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3298 int flags, RtldLockState *lockstate) 3299 { 3300 3301 if (obj->relocated) 3302 return (0); 3303 obj->relocated = true; 3304 if (obj != rtldobj) 3305 dbg("relocating \"%s\"", obj->path); 3306 3307 if (obj->symtab == NULL || obj->strtab == NULL || 3308 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3309 dbg("object %s has no run-time symbol table", obj->path); 3310 3311 /* There are relocations to the write-protected text segment. */ 3312 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3313 return (-1); 3314 3315 /* Process the non-PLT non-IFUNC relocations. */ 3316 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3317 return (-1); 3318 reloc_relr(obj); 3319 3320 /* Re-protected the text segment. */ 3321 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3322 return (-1); 3323 3324 /* Set the special PLT or GOT entries. */ 3325 init_pltgot(obj); 3326 3327 /* Process the PLT relocations. */ 3328 if (reloc_plt(obj, flags, lockstate) == -1) 3329 return (-1); 3330 /* Relocate the jump slots if we are doing immediate binding. */ 3331 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3332 lockstate) == -1) 3333 return (-1); 3334 3335 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3336 return (-1); 3337 3338 /* 3339 * Set up the magic number and version in the Obj_Entry. These 3340 * were checked in the crt1.o from the original ElfKit, so we 3341 * set them for backward compatibility. 3342 */ 3343 obj->magic = RTLD_MAGIC; 3344 obj->version = RTLD_VERSION; 3345 3346 return (0); 3347 } 3348 3349 /* 3350 * Relocate newly-loaded shared objects. The argument is a pointer to 3351 * the Obj_Entry for the first such object. All objects from the first 3352 * to the end of the list of objects are relocated. Returns 0 on success, 3353 * or -1 on failure. 3354 */ 3355 static int 3356 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3357 int flags, RtldLockState *lockstate) 3358 { 3359 Obj_Entry *obj; 3360 int error; 3361 3362 for (error = 0, obj = first; obj != NULL; 3363 obj = TAILQ_NEXT(obj, next)) { 3364 if (obj->marker) 3365 continue; 3366 error = relocate_object(obj, bind_now, rtldobj, flags, 3367 lockstate); 3368 if (error == -1) 3369 break; 3370 } 3371 return (error); 3372 } 3373 3374 /* 3375 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3376 * referencing STT_GNU_IFUNC symbols is postponed till the other 3377 * relocations are done. The indirect functions specified as 3378 * ifunc are allowed to call other symbols, so we need to have 3379 * objects relocated before asking for resolution from indirects. 3380 * 3381 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3382 * instead of the usual lazy handling of PLT slots. It is 3383 * consistent with how GNU does it. 3384 */ 3385 static int 3386 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3387 RtldLockState *lockstate) 3388 { 3389 3390 if (obj->ifuncs_resolved) 3391 return (0); 3392 obj->ifuncs_resolved = true; 3393 if (!obj->irelative && !obj->irelative_nonplt && 3394 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3395 !obj->non_plt_gnu_ifunc) 3396 return (0); 3397 if (obj_disable_relro(obj) == -1 || 3398 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3399 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3400 lockstate) == -1) || 3401 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3402 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3403 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3404 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3405 obj_enforce_relro(obj) == -1) 3406 return (-1); 3407 return (0); 3408 } 3409 3410 static int 3411 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3412 RtldLockState *lockstate) 3413 { 3414 Objlist_Entry *elm; 3415 Obj_Entry *obj; 3416 3417 STAILQ_FOREACH(elm, list, link) { 3418 obj = elm->obj; 3419 if (obj->marker) 3420 continue; 3421 if (resolve_object_ifunc(obj, bind_now, flags, 3422 lockstate) == -1) 3423 return (-1); 3424 } 3425 return (0); 3426 } 3427 3428 /* 3429 * Cleanup procedure. It will be called (by the atexit mechanism) just 3430 * before the process exits. 3431 */ 3432 static void 3433 rtld_exit(void) 3434 { 3435 RtldLockState lockstate; 3436 3437 wlock_acquire(rtld_bind_lock, &lockstate); 3438 dbg("rtld_exit()"); 3439 objlist_call_fini(&list_fini, NULL, &lockstate); 3440 /* No need to remove the items from the list, since we are exiting. */ 3441 if (!libmap_disable) 3442 lm_fini(); 3443 lock_release(rtld_bind_lock, &lockstate); 3444 } 3445 3446 static void 3447 rtld_nop_exit(void) 3448 { 3449 } 3450 3451 /* 3452 * Iterate over a search path, translate each element, and invoke the 3453 * callback on the result. 3454 */ 3455 static void * 3456 path_enumerate(const char *path, path_enum_proc callback, 3457 const char *refobj_path, void *arg) 3458 { 3459 const char *trans; 3460 if (path == NULL) 3461 return (NULL); 3462 3463 path += strspn(path, ":;"); 3464 while (*path != '\0') { 3465 size_t len; 3466 char *res; 3467 3468 len = strcspn(path, ":;"); 3469 trans = lm_findn(refobj_path, path, len); 3470 if (trans) 3471 res = callback(trans, strlen(trans), arg); 3472 else 3473 res = callback(path, len, arg); 3474 3475 if (res != NULL) 3476 return (res); 3477 3478 path += len; 3479 path += strspn(path, ":;"); 3480 } 3481 3482 return (NULL); 3483 } 3484 3485 struct try_library_args { 3486 const char *name; 3487 size_t namelen; 3488 char *buffer; 3489 size_t buflen; 3490 int fd; 3491 }; 3492 3493 static void * 3494 try_library_path(const char *dir, size_t dirlen, void *param) 3495 { 3496 struct try_library_args *arg; 3497 int fd; 3498 3499 arg = param; 3500 if (*dir == '/' || trust) { 3501 char *pathname; 3502 3503 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3504 return (NULL); 3505 3506 pathname = arg->buffer; 3507 strncpy(pathname, dir, dirlen); 3508 pathname[dirlen] = '/'; 3509 strcpy(pathname + dirlen + 1, arg->name); 3510 3511 dbg(" Trying \"%s\"", pathname); 3512 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3513 if (fd >= 0) { 3514 dbg(" Opened \"%s\", fd %d", pathname, fd); 3515 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3516 strcpy(pathname, arg->buffer); 3517 arg->fd = fd; 3518 return (pathname); 3519 } else { 3520 dbg(" Failed to open \"%s\": %s", 3521 pathname, rtld_strerror(errno)); 3522 } 3523 } 3524 return (NULL); 3525 } 3526 3527 static char * 3528 search_library_path(const char *name, const char *path, 3529 const char *refobj_path, int *fdp) 3530 { 3531 char *p; 3532 struct try_library_args arg; 3533 3534 if (path == NULL) 3535 return (NULL); 3536 3537 arg.name = name; 3538 arg.namelen = strlen(name); 3539 arg.buffer = xmalloc(PATH_MAX); 3540 arg.buflen = PATH_MAX; 3541 arg.fd = -1; 3542 3543 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3544 *fdp = arg.fd; 3545 3546 free(arg.buffer); 3547 3548 return (p); 3549 } 3550 3551 3552 /* 3553 * Finds the library with the given name using the directory descriptors 3554 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3555 * 3556 * Returns a freshly-opened close-on-exec file descriptor for the library, 3557 * or -1 if the library cannot be found. 3558 */ 3559 static char * 3560 search_library_pathfds(const char *name, const char *path, int *fdp) 3561 { 3562 char *envcopy, *fdstr, *found, *last_token; 3563 size_t len; 3564 int dirfd, fd; 3565 3566 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3567 3568 /* Don't load from user-specified libdirs into setuid binaries. */ 3569 if (!trust) 3570 return (NULL); 3571 3572 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3573 if (path == NULL) 3574 return (NULL); 3575 3576 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3577 if (name[0] == '/') { 3578 dbg("Absolute path (%s) passed to %s", name, __func__); 3579 return (NULL); 3580 } 3581 3582 /* 3583 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3584 * copy of the path, as strtok_r rewrites separator tokens 3585 * with '\0'. 3586 */ 3587 found = NULL; 3588 envcopy = xstrdup(path); 3589 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3590 fdstr = strtok_r(NULL, ":", &last_token)) { 3591 dirfd = parse_integer(fdstr); 3592 if (dirfd < 0) { 3593 _rtld_error("failed to parse directory FD: '%s'", 3594 fdstr); 3595 break; 3596 } 3597 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3598 if (fd >= 0) { 3599 *fdp = fd; 3600 len = strlen(fdstr) + strlen(name) + 3; 3601 found = xmalloc(len); 3602 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3603 _rtld_error("error generating '%d/%s'", 3604 dirfd, name); 3605 rtld_die(); 3606 } 3607 dbg("open('%s') => %d", found, fd); 3608 break; 3609 } 3610 } 3611 free(envcopy); 3612 3613 return (found); 3614 } 3615 3616 3617 int 3618 dlclose(void *handle) 3619 { 3620 RtldLockState lockstate; 3621 int error; 3622 3623 wlock_acquire(rtld_bind_lock, &lockstate); 3624 error = dlclose_locked(handle, &lockstate); 3625 lock_release(rtld_bind_lock, &lockstate); 3626 return (error); 3627 } 3628 3629 static int 3630 dlclose_locked(void *handle, RtldLockState *lockstate) 3631 { 3632 Obj_Entry *root; 3633 3634 root = dlcheck(handle); 3635 if (root == NULL) 3636 return (-1); 3637 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3638 root->path); 3639 3640 /* Unreference the object and its dependencies. */ 3641 root->dl_refcount--; 3642 3643 if (root->refcount == 1) { 3644 /* 3645 * The object will be no longer referenced, so we must unload it. 3646 * First, call the fini functions. 3647 */ 3648 objlist_call_fini(&list_fini, root, lockstate); 3649 3650 unref_dag(root); 3651 3652 /* Finish cleaning up the newly-unreferenced objects. */ 3653 GDB_STATE(RT_DELETE,&root->linkmap); 3654 unload_object(root, lockstate); 3655 GDB_STATE(RT_CONSISTENT,NULL); 3656 } else 3657 unref_dag(root); 3658 3659 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3660 return (0); 3661 } 3662 3663 char * 3664 dlerror(void) 3665 { 3666 if (*(lockinfo.dlerror_seen()) != 0) 3667 return (NULL); 3668 *lockinfo.dlerror_seen() = 1; 3669 return (lockinfo.dlerror_loc()); 3670 } 3671 3672 /* 3673 * This function is deprecated and has no effect. 3674 */ 3675 void 3676 dllockinit(void *context, 3677 void *(*_lock_create)(void *context) __unused, 3678 void (*_rlock_acquire)(void *lock) __unused, 3679 void (*_wlock_acquire)(void *lock) __unused, 3680 void (*_lock_release)(void *lock) __unused, 3681 void (*_lock_destroy)(void *lock) __unused, 3682 void (*context_destroy)(void *context)) 3683 { 3684 static void *cur_context; 3685 static void (*cur_context_destroy)(void *); 3686 3687 /* Just destroy the context from the previous call, if necessary. */ 3688 if (cur_context_destroy != NULL) 3689 cur_context_destroy(cur_context); 3690 cur_context = context; 3691 cur_context_destroy = context_destroy; 3692 } 3693 3694 void * 3695 dlopen(const char *name, int mode) 3696 { 3697 3698 return (rtld_dlopen(name, -1, mode)); 3699 } 3700 3701 void * 3702 fdlopen(int fd, int mode) 3703 { 3704 3705 return (rtld_dlopen(NULL, fd, mode)); 3706 } 3707 3708 static void * 3709 rtld_dlopen(const char *name, int fd, int mode) 3710 { 3711 RtldLockState lockstate; 3712 int lo_flags; 3713 3714 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3715 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3716 if (ld_tracing != NULL) { 3717 rlock_acquire(rtld_bind_lock, &lockstate); 3718 if (sigsetjmp(lockstate.env, 0) != 0) 3719 lock_upgrade(rtld_bind_lock, &lockstate); 3720 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3721 lock_release(rtld_bind_lock, &lockstate); 3722 } 3723 lo_flags = RTLD_LO_DLOPEN; 3724 if (mode & RTLD_NODELETE) 3725 lo_flags |= RTLD_LO_NODELETE; 3726 if (mode & RTLD_NOLOAD) 3727 lo_flags |= RTLD_LO_NOLOAD; 3728 if (mode & RTLD_DEEPBIND) 3729 lo_flags |= RTLD_LO_DEEPBIND; 3730 if (ld_tracing != NULL) 3731 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3732 3733 return (dlopen_object(name, fd, obj_main, lo_flags, 3734 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3735 } 3736 3737 static void 3738 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3739 { 3740 3741 obj->dl_refcount--; 3742 unref_dag(obj); 3743 if (obj->refcount == 0) 3744 unload_object(obj, lockstate); 3745 } 3746 3747 static Obj_Entry * 3748 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3749 int mode, RtldLockState *lockstate) 3750 { 3751 Obj_Entry *obj; 3752 Objlist initlist; 3753 RtldLockState mlockstate; 3754 int result; 3755 3756 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3757 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3758 refobj->path, lo_flags, mode); 3759 objlist_init(&initlist); 3760 3761 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3762 wlock_acquire(rtld_bind_lock, &mlockstate); 3763 lockstate = &mlockstate; 3764 } 3765 GDB_STATE(RT_ADD,NULL); 3766 3767 obj = NULL; 3768 if (name == NULL && fd == -1) { 3769 obj = obj_main; 3770 obj->refcount++; 3771 } else { 3772 obj = load_object(name, fd, refobj, lo_flags); 3773 } 3774 3775 if (obj) { 3776 obj->dl_refcount++; 3777 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3778 objlist_push_tail(&list_global, obj); 3779 3780 if (!obj->init_done) { 3781 /* We loaded something new and have to init something. */ 3782 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3783 obj->deepbind = true; 3784 result = 0; 3785 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3786 obj->static_tls && !allocate_tls_offset(obj)) { 3787 _rtld_error("%s: No space available " 3788 "for static Thread Local Storage", obj->path); 3789 result = -1; 3790 } 3791 if (result != -1) 3792 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3793 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3794 init_dag(obj); 3795 ref_dag(obj); 3796 if (result != -1) 3797 result = rtld_verify_versions(&obj->dagmembers); 3798 if (result != -1 && ld_tracing) 3799 goto trace; 3800 if (result == -1 || relocate_object_dag(obj, 3801 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3802 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3803 lockstate) == -1) { 3804 dlopen_cleanup(obj, lockstate); 3805 obj = NULL; 3806 } else if (lo_flags & RTLD_LO_EARLY) { 3807 /* 3808 * Do not call the init functions for early loaded 3809 * filtees. The image is still not initialized enough 3810 * for them to work. 3811 * 3812 * Our object is found by the global object list and 3813 * will be ordered among all init calls done right 3814 * before transferring control to main. 3815 */ 3816 } else { 3817 /* Make list of init functions to call. */ 3818 initlist_add_objects(obj, obj, &initlist); 3819 } 3820 /* 3821 * Process all no_delete or global objects here, given 3822 * them own DAGs to prevent their dependencies from being 3823 * unloaded. This has to be done after we have loaded all 3824 * of the dependencies, so that we do not miss any. 3825 */ 3826 if (obj != NULL) 3827 process_z(obj); 3828 } else { 3829 /* 3830 * Bump the reference counts for objects on this DAG. If 3831 * this is the first dlopen() call for the object that was 3832 * already loaded as a dependency, initialize the dag 3833 * starting at it. 3834 */ 3835 init_dag(obj); 3836 ref_dag(obj); 3837 3838 if ((lo_flags & RTLD_LO_TRACE) != 0) 3839 goto trace; 3840 } 3841 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3842 obj->z_nodelete) && !obj->ref_nodel) { 3843 dbg("obj %s nodelete", obj->path); 3844 ref_dag(obj); 3845 obj->z_nodelete = obj->ref_nodel = true; 3846 } 3847 } 3848 3849 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3850 name); 3851 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3852 3853 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3854 map_stacks_exec(lockstate); 3855 if (obj != NULL) 3856 distribute_static_tls(&initlist, lockstate); 3857 } 3858 3859 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3860 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3861 lockstate) == -1) { 3862 objlist_clear(&initlist); 3863 dlopen_cleanup(obj, lockstate); 3864 if (lockstate == &mlockstate) 3865 lock_release(rtld_bind_lock, lockstate); 3866 return (NULL); 3867 } 3868 3869 if (!(lo_flags & RTLD_LO_EARLY)) { 3870 /* Call the init functions. */ 3871 objlist_call_init(&initlist, lockstate); 3872 } 3873 objlist_clear(&initlist); 3874 if (lockstate == &mlockstate) 3875 lock_release(rtld_bind_lock, lockstate); 3876 return (obj); 3877 trace: 3878 trace_loaded_objects(obj, false); 3879 if (lockstate == &mlockstate) 3880 lock_release(rtld_bind_lock, lockstate); 3881 exit(0); 3882 } 3883 3884 static void * 3885 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3886 int flags) 3887 { 3888 DoneList donelist; 3889 const Obj_Entry *obj, *defobj; 3890 const Elf_Sym *def; 3891 SymLook req; 3892 RtldLockState lockstate; 3893 tls_index ti; 3894 void *sym; 3895 int res; 3896 3897 def = NULL; 3898 defobj = NULL; 3899 symlook_init(&req, name); 3900 req.ventry = ve; 3901 req.flags = flags | SYMLOOK_IN_PLT; 3902 req.lockstate = &lockstate; 3903 3904 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3905 rlock_acquire(rtld_bind_lock, &lockstate); 3906 if (sigsetjmp(lockstate.env, 0) != 0) 3907 lock_upgrade(rtld_bind_lock, &lockstate); 3908 if (handle == NULL || handle == RTLD_NEXT || 3909 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3910 3911 if ((obj = obj_from_addr(retaddr)) == NULL) { 3912 _rtld_error("Cannot determine caller's shared object"); 3913 lock_release(rtld_bind_lock, &lockstate); 3914 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3915 return (NULL); 3916 } 3917 if (handle == NULL) { /* Just the caller's shared object. */ 3918 res = symlook_obj(&req, obj); 3919 if (res == 0) { 3920 def = req.sym_out; 3921 defobj = req.defobj_out; 3922 } 3923 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3924 handle == RTLD_SELF) { /* ... caller included */ 3925 if (handle == RTLD_NEXT) 3926 obj = globallist_next(obj); 3927 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3928 if (obj->marker) 3929 continue; 3930 res = symlook_obj(&req, obj); 3931 if (res == 0) { 3932 if (def == NULL || (ld_dynamic_weak && 3933 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3934 def = req.sym_out; 3935 defobj = req.defobj_out; 3936 if (!ld_dynamic_weak || 3937 ELF_ST_BIND(def->st_info) != STB_WEAK) 3938 break; 3939 } 3940 } 3941 } 3942 /* 3943 * Search the dynamic linker itself, and possibly resolve the 3944 * symbol from there. This is how the application links to 3945 * dynamic linker services such as dlopen. 3946 * Note that we ignore ld_dynamic_weak == false case, 3947 * always overriding weak symbols by rtld definitions. 3948 */ 3949 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3950 res = symlook_obj(&req, &obj_rtld); 3951 if (res == 0) { 3952 def = req.sym_out; 3953 defobj = req.defobj_out; 3954 } 3955 } 3956 } else { 3957 assert(handle == RTLD_DEFAULT); 3958 res = symlook_default(&req, obj); 3959 if (res == 0) { 3960 defobj = req.defobj_out; 3961 def = req.sym_out; 3962 } 3963 } 3964 } else { 3965 if ((obj = dlcheck(handle)) == NULL) { 3966 lock_release(rtld_bind_lock, &lockstate); 3967 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3968 return (NULL); 3969 } 3970 3971 donelist_init(&donelist); 3972 if (obj->mainprog) { 3973 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3974 res = symlook_global(&req, &donelist); 3975 if (res == 0) { 3976 def = req.sym_out; 3977 defobj = req.defobj_out; 3978 } 3979 /* 3980 * Search the dynamic linker itself, and possibly resolve the 3981 * symbol from there. This is how the application links to 3982 * dynamic linker services such as dlopen. 3983 */ 3984 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3985 res = symlook_obj(&req, &obj_rtld); 3986 if (res == 0) { 3987 def = req.sym_out; 3988 defobj = req.defobj_out; 3989 } 3990 } 3991 } 3992 else { 3993 /* Search the whole DAG rooted at the given object. */ 3994 res = symlook_list(&req, &obj->dagmembers, &donelist); 3995 if (res == 0) { 3996 def = req.sym_out; 3997 defobj = req.defobj_out; 3998 } 3999 } 4000 } 4001 4002 if (def != NULL) { 4003 lock_release(rtld_bind_lock, &lockstate); 4004 4005 /* 4006 * The value required by the caller is derived from the value 4007 * of the symbol. this is simply the relocated value of the 4008 * symbol. 4009 */ 4010 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 4011 sym = make_function_pointer(def, defobj); 4012 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 4013 sym = rtld_resolve_ifunc(defobj, def); 4014 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4015 ti.ti_module = defobj->tlsindex; 4016 ti.ti_offset = def->st_value; 4017 sym = __tls_get_addr(&ti); 4018 } else 4019 sym = defobj->relocbase + def->st_value; 4020 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4021 return (sym); 4022 } 4023 4024 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4025 ve != NULL ? ve->name : ""); 4026 lock_release(rtld_bind_lock, &lockstate); 4027 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4028 return (NULL); 4029 } 4030 4031 void * 4032 dlsym(void *handle, const char *name) 4033 { 4034 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4035 SYMLOOK_DLSYM)); 4036 } 4037 4038 dlfunc_t 4039 dlfunc(void *handle, const char *name) 4040 { 4041 union { 4042 void *d; 4043 dlfunc_t f; 4044 } rv; 4045 4046 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4047 SYMLOOK_DLSYM); 4048 return (rv.f); 4049 } 4050 4051 void * 4052 dlvsym(void *handle, const char *name, const char *version) 4053 { 4054 Ver_Entry ventry; 4055 4056 ventry.name = version; 4057 ventry.file = NULL; 4058 ventry.hash = elf_hash(version); 4059 ventry.flags= 0; 4060 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4061 SYMLOOK_DLSYM)); 4062 } 4063 4064 int 4065 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4066 { 4067 const Obj_Entry *obj; 4068 RtldLockState lockstate; 4069 4070 rlock_acquire(rtld_bind_lock, &lockstate); 4071 obj = obj_from_addr(addr); 4072 if (obj == NULL) { 4073 _rtld_error("No shared object contains address"); 4074 lock_release(rtld_bind_lock, &lockstate); 4075 return (0); 4076 } 4077 rtld_fill_dl_phdr_info(obj, phdr_info); 4078 lock_release(rtld_bind_lock, &lockstate); 4079 return (1); 4080 } 4081 4082 int 4083 dladdr(const void *addr, Dl_info *info) 4084 { 4085 const Obj_Entry *obj; 4086 const Elf_Sym *def; 4087 void *symbol_addr; 4088 unsigned long symoffset; 4089 RtldLockState lockstate; 4090 4091 rlock_acquire(rtld_bind_lock, &lockstate); 4092 obj = obj_from_addr(addr); 4093 if (obj == NULL) { 4094 _rtld_error("No shared object contains address"); 4095 lock_release(rtld_bind_lock, &lockstate); 4096 return (0); 4097 } 4098 info->dli_fname = obj->path; 4099 info->dli_fbase = obj->mapbase; 4100 info->dli_saddr = (void *)0; 4101 info->dli_sname = NULL; 4102 4103 /* 4104 * Walk the symbol list looking for the symbol whose address is 4105 * closest to the address sent in. 4106 */ 4107 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4108 def = obj->symtab + symoffset; 4109 4110 /* 4111 * For skip the symbol if st_shndx is either SHN_UNDEF or 4112 * SHN_COMMON. 4113 */ 4114 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4115 continue; 4116 4117 /* 4118 * If the symbol is greater than the specified address, or if it 4119 * is further away from addr than the current nearest symbol, 4120 * then reject it. 4121 */ 4122 symbol_addr = obj->relocbase + def->st_value; 4123 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4124 continue; 4125 4126 /* Update our idea of the nearest symbol. */ 4127 info->dli_sname = obj->strtab + def->st_name; 4128 info->dli_saddr = symbol_addr; 4129 4130 /* Exact match? */ 4131 if (info->dli_saddr == addr) 4132 break; 4133 } 4134 lock_release(rtld_bind_lock, &lockstate); 4135 return (1); 4136 } 4137 4138 int 4139 dlinfo(void *handle, int request, void *p) 4140 { 4141 const Obj_Entry *obj; 4142 RtldLockState lockstate; 4143 int error; 4144 4145 rlock_acquire(rtld_bind_lock, &lockstate); 4146 4147 if (handle == NULL || handle == RTLD_SELF) { 4148 void *retaddr; 4149 4150 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4151 if ((obj = obj_from_addr(retaddr)) == NULL) 4152 _rtld_error("Cannot determine caller's shared object"); 4153 } else 4154 obj = dlcheck(handle); 4155 4156 if (obj == NULL) { 4157 lock_release(rtld_bind_lock, &lockstate); 4158 return (-1); 4159 } 4160 4161 error = 0; 4162 switch (request) { 4163 case RTLD_DI_LINKMAP: 4164 *((struct link_map const **)p) = &obj->linkmap; 4165 break; 4166 case RTLD_DI_ORIGIN: 4167 error = rtld_dirname(obj->path, p); 4168 break; 4169 4170 case RTLD_DI_SERINFOSIZE: 4171 case RTLD_DI_SERINFO: 4172 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4173 break; 4174 4175 default: 4176 _rtld_error("Invalid request %d passed to dlinfo()", request); 4177 error = -1; 4178 } 4179 4180 lock_release(rtld_bind_lock, &lockstate); 4181 4182 return (error); 4183 } 4184 4185 static void 4186 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4187 { 4188 uintptr_t **dtvp; 4189 4190 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4191 phdr_info->dlpi_name = obj->path; 4192 phdr_info->dlpi_phdr = obj->phdr; 4193 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4194 phdr_info->dlpi_tls_modid = obj->tlsindex; 4195 dtvp = &_tcb_get()->tcb_dtv; 4196 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4197 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4198 phdr_info->dlpi_adds = obj_loads; 4199 phdr_info->dlpi_subs = obj_loads - obj_count; 4200 } 4201 4202 int 4203 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4204 { 4205 struct dl_phdr_info phdr_info; 4206 Obj_Entry *obj, marker; 4207 RtldLockState bind_lockstate, phdr_lockstate; 4208 int error; 4209 4210 init_marker(&marker); 4211 error = 0; 4212 4213 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4214 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4215 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4216 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4217 rtld_fill_dl_phdr_info(obj, &phdr_info); 4218 hold_object(obj); 4219 lock_release(rtld_bind_lock, &bind_lockstate); 4220 4221 error = callback(&phdr_info, sizeof phdr_info, param); 4222 4223 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4224 unhold_object(obj); 4225 obj = globallist_next(&marker); 4226 TAILQ_REMOVE(&obj_list, &marker, next); 4227 if (error != 0) { 4228 lock_release(rtld_bind_lock, &bind_lockstate); 4229 lock_release(rtld_phdr_lock, &phdr_lockstate); 4230 return (error); 4231 } 4232 } 4233 4234 if (error == 0) { 4235 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4236 lock_release(rtld_bind_lock, &bind_lockstate); 4237 error = callback(&phdr_info, sizeof(phdr_info), param); 4238 } 4239 lock_release(rtld_phdr_lock, &phdr_lockstate); 4240 return (error); 4241 } 4242 4243 static void * 4244 fill_search_info(const char *dir, size_t dirlen, void *param) 4245 { 4246 struct fill_search_info_args *arg; 4247 4248 arg = param; 4249 4250 if (arg->request == RTLD_DI_SERINFOSIZE) { 4251 arg->serinfo->dls_cnt ++; 4252 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4253 } else { 4254 struct dl_serpath *s_entry; 4255 4256 s_entry = arg->serpath; 4257 s_entry->dls_name = arg->strspace; 4258 s_entry->dls_flags = arg->flags; 4259 4260 strncpy(arg->strspace, dir, dirlen); 4261 arg->strspace[dirlen] = '\0'; 4262 4263 arg->strspace += dirlen + 1; 4264 arg->serpath++; 4265 } 4266 4267 return (NULL); 4268 } 4269 4270 static int 4271 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4272 { 4273 struct dl_serinfo _info; 4274 struct fill_search_info_args args; 4275 4276 args.request = RTLD_DI_SERINFOSIZE; 4277 args.serinfo = &_info; 4278 4279 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4280 _info.dls_cnt = 0; 4281 4282 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4283 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4284 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4285 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4286 if (!obj->z_nodeflib) 4287 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4288 4289 4290 if (request == RTLD_DI_SERINFOSIZE) { 4291 info->dls_size = _info.dls_size; 4292 info->dls_cnt = _info.dls_cnt; 4293 return (0); 4294 } 4295 4296 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4297 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4298 return (-1); 4299 } 4300 4301 args.request = RTLD_DI_SERINFO; 4302 args.serinfo = info; 4303 args.serpath = &info->dls_serpath[0]; 4304 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4305 4306 args.flags = LA_SER_RUNPATH; 4307 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4308 return (-1); 4309 4310 args.flags = LA_SER_LIBPATH; 4311 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4312 return (-1); 4313 4314 args.flags = LA_SER_RUNPATH; 4315 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4316 return (-1); 4317 4318 args.flags = LA_SER_CONFIG; 4319 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4320 != NULL) 4321 return (-1); 4322 4323 args.flags = LA_SER_DEFAULT; 4324 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4325 fill_search_info, NULL, &args) != NULL) 4326 return (-1); 4327 return (0); 4328 } 4329 4330 static int 4331 rtld_dirname(const char *path, char *bname) 4332 { 4333 const char *endp; 4334 4335 /* Empty or NULL string gets treated as "." */ 4336 if (path == NULL || *path == '\0') { 4337 bname[0] = '.'; 4338 bname[1] = '\0'; 4339 return (0); 4340 } 4341 4342 /* Strip trailing slashes */ 4343 endp = path + strlen(path) - 1; 4344 while (endp > path && *endp == '/') 4345 endp--; 4346 4347 /* Find the start of the dir */ 4348 while (endp > path && *endp != '/') 4349 endp--; 4350 4351 /* Either the dir is "/" or there are no slashes */ 4352 if (endp == path) { 4353 bname[0] = *endp == '/' ? '/' : '.'; 4354 bname[1] = '\0'; 4355 return (0); 4356 } else { 4357 do { 4358 endp--; 4359 } while (endp > path && *endp == '/'); 4360 } 4361 4362 if (endp - path + 2 > PATH_MAX) 4363 { 4364 _rtld_error("Filename is too long: %s", path); 4365 return(-1); 4366 } 4367 4368 strncpy(bname, path, endp - path + 1); 4369 bname[endp - path + 1] = '\0'; 4370 return (0); 4371 } 4372 4373 static int 4374 rtld_dirname_abs(const char *path, char *base) 4375 { 4376 char *last; 4377 4378 if (realpath(path, base) == NULL) { 4379 _rtld_error("realpath \"%s\" failed (%s)", path, 4380 rtld_strerror(errno)); 4381 return (-1); 4382 } 4383 dbg("%s -> %s", path, base); 4384 last = strrchr(base, '/'); 4385 if (last == NULL) { 4386 _rtld_error("non-abs result from realpath \"%s\"", path); 4387 return (-1); 4388 } 4389 if (last != base) 4390 *last = '\0'; 4391 return (0); 4392 } 4393 4394 static void 4395 linkmap_add(Obj_Entry *obj) 4396 { 4397 struct link_map *l, *prev; 4398 4399 l = &obj->linkmap; 4400 l->l_name = obj->path; 4401 l->l_base = obj->mapbase; 4402 l->l_ld = obj->dynamic; 4403 l->l_addr = obj->relocbase; 4404 4405 if (r_debug.r_map == NULL) { 4406 r_debug.r_map = l; 4407 return; 4408 } 4409 4410 /* 4411 * Scan to the end of the list, but not past the entry for the 4412 * dynamic linker, which we want to keep at the very end. 4413 */ 4414 for (prev = r_debug.r_map; 4415 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4416 prev = prev->l_next) 4417 ; 4418 4419 /* Link in the new entry. */ 4420 l->l_prev = prev; 4421 l->l_next = prev->l_next; 4422 if (l->l_next != NULL) 4423 l->l_next->l_prev = l; 4424 prev->l_next = l; 4425 } 4426 4427 static void 4428 linkmap_delete(Obj_Entry *obj) 4429 { 4430 struct link_map *l; 4431 4432 l = &obj->linkmap; 4433 if (l->l_prev == NULL) { 4434 if ((r_debug.r_map = l->l_next) != NULL) 4435 l->l_next->l_prev = NULL; 4436 return; 4437 } 4438 4439 if ((l->l_prev->l_next = l->l_next) != NULL) 4440 l->l_next->l_prev = l->l_prev; 4441 } 4442 4443 /* 4444 * Function for the debugger to set a breakpoint on to gain control. 4445 * 4446 * The two parameters allow the debugger to easily find and determine 4447 * what the runtime loader is doing and to whom it is doing it. 4448 * 4449 * When the loadhook trap is hit (r_debug_state, set at program 4450 * initialization), the arguments can be found on the stack: 4451 * 4452 * +8 struct link_map *m 4453 * +4 struct r_debug *rd 4454 * +0 RetAddr 4455 */ 4456 void 4457 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4458 { 4459 /* 4460 * The following is a hack to force the compiler to emit calls to 4461 * this function, even when optimizing. If the function is empty, 4462 * the compiler is not obliged to emit any code for calls to it, 4463 * even when marked __noinline. However, gdb depends on those 4464 * calls being made. 4465 */ 4466 __compiler_membar(); 4467 } 4468 4469 /* 4470 * A function called after init routines have completed. This can be used to 4471 * break before a program's entry routine is called, and can be used when 4472 * main is not available in the symbol table. 4473 */ 4474 void 4475 _r_debug_postinit(struct link_map *m __unused) 4476 { 4477 4478 /* See r_debug_state(). */ 4479 __compiler_membar(); 4480 } 4481 4482 static void 4483 release_object(Obj_Entry *obj) 4484 { 4485 4486 if (obj->holdcount > 0) { 4487 obj->unholdfree = true; 4488 return; 4489 } 4490 munmap(obj->mapbase, obj->mapsize); 4491 linkmap_delete(obj); 4492 obj_free(obj); 4493 } 4494 4495 /* 4496 * Get address of the pointer variable in the main program. 4497 * Prefer non-weak symbol over the weak one. 4498 */ 4499 static const void ** 4500 get_program_var_addr(const char *name, RtldLockState *lockstate) 4501 { 4502 SymLook req; 4503 DoneList donelist; 4504 4505 symlook_init(&req, name); 4506 req.lockstate = lockstate; 4507 donelist_init(&donelist); 4508 if (symlook_global(&req, &donelist) != 0) 4509 return (NULL); 4510 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4511 return ((const void **)make_function_pointer(req.sym_out, 4512 req.defobj_out)); 4513 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4514 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4515 else 4516 return ((const void **)(req.defobj_out->relocbase + 4517 req.sym_out->st_value)); 4518 } 4519 4520 /* 4521 * Set a pointer variable in the main program to the given value. This 4522 * is used to set key variables such as "environ" before any of the 4523 * init functions are called. 4524 */ 4525 static void 4526 set_program_var(const char *name, const void *value) 4527 { 4528 const void **addr; 4529 4530 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4531 dbg("\"%s\": *%p <-- %p", name, addr, value); 4532 *addr = value; 4533 } 4534 } 4535 4536 /* 4537 * Search the global objects, including dependencies and main object, 4538 * for the given symbol. 4539 */ 4540 static int 4541 symlook_global(SymLook *req, DoneList *donelist) 4542 { 4543 SymLook req1; 4544 const Objlist_Entry *elm; 4545 int res; 4546 4547 symlook_init_from_req(&req1, req); 4548 4549 /* Search all objects loaded at program start up. */ 4550 if (req->defobj_out == NULL || (ld_dynamic_weak && 4551 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4552 res = symlook_list(&req1, &list_main, donelist); 4553 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4554 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4555 req->sym_out = req1.sym_out; 4556 req->defobj_out = req1.defobj_out; 4557 assert(req->defobj_out != NULL); 4558 } 4559 } 4560 4561 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4562 STAILQ_FOREACH(elm, &list_global, link) { 4563 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4564 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4565 break; 4566 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4567 if (res == 0 && (req->defobj_out == NULL || 4568 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4569 req->sym_out = req1.sym_out; 4570 req->defobj_out = req1.defobj_out; 4571 assert(req->defobj_out != NULL); 4572 } 4573 } 4574 4575 return (req->sym_out != NULL ? 0 : ESRCH); 4576 } 4577 4578 /* 4579 * Given a symbol name in a referencing object, find the corresponding 4580 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4581 * no definition was found. Returns a pointer to the Obj_Entry of the 4582 * defining object via the reference parameter DEFOBJ_OUT. 4583 */ 4584 static int 4585 symlook_default(SymLook *req, const Obj_Entry *refobj) 4586 { 4587 DoneList donelist; 4588 const Objlist_Entry *elm; 4589 SymLook req1; 4590 int res; 4591 4592 donelist_init(&donelist); 4593 symlook_init_from_req(&req1, req); 4594 4595 /* 4596 * Look first in the referencing object if linked symbolically, 4597 * and similarly handle protected symbols. 4598 */ 4599 res = symlook_obj(&req1, refobj); 4600 if (res == 0 && (refobj->symbolic || 4601 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4602 req->sym_out = req1.sym_out; 4603 req->defobj_out = req1.defobj_out; 4604 assert(req->defobj_out != NULL); 4605 } 4606 if (refobj->symbolic || req->defobj_out != NULL) 4607 donelist_check(&donelist, refobj); 4608 4609 if (!refobj->deepbind) 4610 symlook_global(req, &donelist); 4611 4612 /* Search all dlopened DAGs containing the referencing object. */ 4613 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4614 if (req->sym_out != NULL && (!ld_dynamic_weak || 4615 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4616 break; 4617 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4618 if (res == 0 && (req->sym_out == NULL || 4619 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4620 req->sym_out = req1.sym_out; 4621 req->defobj_out = req1.defobj_out; 4622 assert(req->defobj_out != NULL); 4623 } 4624 } 4625 4626 if (refobj->deepbind) 4627 symlook_global(req, &donelist); 4628 4629 /* 4630 * Search the dynamic linker itself, and possibly resolve the 4631 * symbol from there. This is how the application links to 4632 * dynamic linker services such as dlopen. 4633 */ 4634 if (req->sym_out == NULL || 4635 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4636 res = symlook_obj(&req1, &obj_rtld); 4637 if (res == 0) { 4638 req->sym_out = req1.sym_out; 4639 req->defobj_out = req1.defobj_out; 4640 assert(req->defobj_out != NULL); 4641 } 4642 } 4643 4644 return (req->sym_out != NULL ? 0 : ESRCH); 4645 } 4646 4647 static int 4648 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4649 { 4650 const Elf_Sym *def; 4651 const Obj_Entry *defobj; 4652 const Objlist_Entry *elm; 4653 SymLook req1; 4654 int res; 4655 4656 def = NULL; 4657 defobj = NULL; 4658 STAILQ_FOREACH(elm, objlist, link) { 4659 if (donelist_check(dlp, elm->obj)) 4660 continue; 4661 symlook_init_from_req(&req1, req); 4662 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4663 if (def == NULL || (ld_dynamic_weak && 4664 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4665 def = req1.sym_out; 4666 defobj = req1.defobj_out; 4667 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4668 break; 4669 } 4670 } 4671 } 4672 if (def != NULL) { 4673 req->sym_out = def; 4674 req->defobj_out = defobj; 4675 return (0); 4676 } 4677 return (ESRCH); 4678 } 4679 4680 /* 4681 * Search the chain of DAGS cointed to by the given Needed_Entry 4682 * for a symbol of the given name. Each DAG is scanned completely 4683 * before advancing to the next one. Returns a pointer to the symbol, 4684 * or NULL if no definition was found. 4685 */ 4686 static int 4687 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4688 { 4689 const Elf_Sym *def; 4690 const Needed_Entry *n; 4691 const Obj_Entry *defobj; 4692 SymLook req1; 4693 int res; 4694 4695 def = NULL; 4696 defobj = NULL; 4697 symlook_init_from_req(&req1, req); 4698 for (n = needed; n != NULL; n = n->next) { 4699 if (n->obj == NULL || 4700 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4701 continue; 4702 if (def == NULL || (ld_dynamic_weak && 4703 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4704 def = req1.sym_out; 4705 defobj = req1.defobj_out; 4706 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4707 break; 4708 } 4709 } 4710 if (def != NULL) { 4711 req->sym_out = def; 4712 req->defobj_out = defobj; 4713 return (0); 4714 } 4715 return (ESRCH); 4716 } 4717 4718 static int 4719 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, 4720 Needed_Entry *needed) 4721 { 4722 DoneList donelist; 4723 int flags; 4724 4725 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; 4726 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4727 donelist_init(&donelist); 4728 symlook_init_from_req(req1, req); 4729 return (symlook_needed(req1, needed, &donelist)); 4730 } 4731 4732 /* 4733 * Search the symbol table of a single shared object for a symbol of 4734 * the given name and version, if requested. Returns a pointer to the 4735 * symbol, or NULL if no definition was found. If the object is 4736 * filter, return filtered symbol from filtee. 4737 * 4738 * The symbol's hash value is passed in for efficiency reasons; that 4739 * eliminates many recomputations of the hash value. 4740 */ 4741 int 4742 symlook_obj(SymLook *req, const Obj_Entry *obj) 4743 { 4744 SymLook req1; 4745 int res, mres; 4746 4747 /* 4748 * If there is at least one valid hash at this point, we prefer to 4749 * use the faster GNU version if available. 4750 */ 4751 if (obj->valid_hash_gnu) 4752 mres = symlook_obj1_gnu(req, obj); 4753 else if (obj->valid_hash_sysv) 4754 mres = symlook_obj1_sysv(req, obj); 4755 else 4756 return (EINVAL); 4757 4758 if (mres == 0) { 4759 if (obj->needed_filtees != NULL) { 4760 res = symlook_obj_load_filtees(req, &req1, obj, 4761 obj->needed_filtees); 4762 if (res == 0) { 4763 req->sym_out = req1.sym_out; 4764 req->defobj_out = req1.defobj_out; 4765 } 4766 return (res); 4767 } 4768 if (obj->needed_aux_filtees != NULL) { 4769 res = symlook_obj_load_filtees(req, &req1, obj, 4770 obj->needed_aux_filtees); 4771 if (res == 0) { 4772 req->sym_out = req1.sym_out; 4773 req->defobj_out = req1.defobj_out; 4774 return (res); 4775 } 4776 } 4777 } 4778 return (mres); 4779 } 4780 4781 /* Symbol match routine common to both hash functions */ 4782 static bool 4783 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4784 const unsigned long symnum) 4785 { 4786 Elf_Versym verndx; 4787 const Elf_Sym *symp; 4788 const char *strp; 4789 4790 symp = obj->symtab + symnum; 4791 strp = obj->strtab + symp->st_name; 4792 4793 switch (ELF_ST_TYPE(symp->st_info)) { 4794 case STT_FUNC: 4795 case STT_NOTYPE: 4796 case STT_OBJECT: 4797 case STT_COMMON: 4798 case STT_GNU_IFUNC: 4799 if (symp->st_value == 0) 4800 return (false); 4801 /* fallthrough */ 4802 case STT_TLS: 4803 if (symp->st_shndx != SHN_UNDEF) 4804 break; 4805 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4806 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4807 break; 4808 /* fallthrough */ 4809 default: 4810 return (false); 4811 } 4812 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4813 return (false); 4814 4815 if (req->ventry == NULL) { 4816 if (obj->versyms != NULL) { 4817 verndx = VER_NDX(obj->versyms[symnum]); 4818 if (verndx > obj->vernum) { 4819 _rtld_error( 4820 "%s: symbol %s references wrong version %d", 4821 obj->path, obj->strtab + symnum, verndx); 4822 return (false); 4823 } 4824 /* 4825 * If we are not called from dlsym (i.e. this 4826 * is a normal relocation from unversioned 4827 * binary), accept the symbol immediately if 4828 * it happens to have first version after this 4829 * shared object became versioned. Otherwise, 4830 * if symbol is versioned and not hidden, 4831 * remember it. If it is the only symbol with 4832 * this name exported by the shared object, it 4833 * will be returned as a match by the calling 4834 * function. If symbol is global (verndx < 2) 4835 * accept it unconditionally. 4836 */ 4837 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4838 verndx == VER_NDX_GIVEN) { 4839 result->sym_out = symp; 4840 return (true); 4841 } 4842 else if (verndx >= VER_NDX_GIVEN) { 4843 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4844 == 0) { 4845 if (result->vsymp == NULL) 4846 result->vsymp = symp; 4847 result->vcount++; 4848 } 4849 return (false); 4850 } 4851 } 4852 result->sym_out = symp; 4853 return (true); 4854 } 4855 if (obj->versyms == NULL) { 4856 if (object_match_name(obj, req->ventry->name)) { 4857 _rtld_error("%s: object %s should provide version %s " 4858 "for symbol %s", obj_rtld.path, obj->path, 4859 req->ventry->name, obj->strtab + symnum); 4860 return (false); 4861 } 4862 } else { 4863 verndx = VER_NDX(obj->versyms[symnum]); 4864 if (verndx > obj->vernum) { 4865 _rtld_error("%s: symbol %s references wrong version %d", 4866 obj->path, obj->strtab + symnum, verndx); 4867 return (false); 4868 } 4869 if (obj->vertab[verndx].hash != req->ventry->hash || 4870 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4871 /* 4872 * Version does not match. Look if this is a 4873 * global symbol and if it is not hidden. If 4874 * global symbol (verndx < 2) is available, 4875 * use it. Do not return symbol if we are 4876 * called by dlvsym, because dlvsym looks for 4877 * a specific version and default one is not 4878 * what dlvsym wants. 4879 */ 4880 if ((req->flags & SYMLOOK_DLSYM) || 4881 (verndx >= VER_NDX_GIVEN) || 4882 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4883 return (false); 4884 } 4885 } 4886 result->sym_out = symp; 4887 return (true); 4888 } 4889 4890 /* 4891 * Search for symbol using SysV hash function. 4892 * obj->buckets is known not to be NULL at this point; the test for this was 4893 * performed with the obj->valid_hash_sysv assignment. 4894 */ 4895 static int 4896 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4897 { 4898 unsigned long symnum; 4899 Sym_Match_Result matchres; 4900 4901 matchres.sym_out = NULL; 4902 matchres.vsymp = NULL; 4903 matchres.vcount = 0; 4904 4905 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4906 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4907 if (symnum >= obj->nchains) 4908 return (ESRCH); /* Bad object */ 4909 4910 if (matched_symbol(req, obj, &matchres, symnum)) { 4911 req->sym_out = matchres.sym_out; 4912 req->defobj_out = obj; 4913 return (0); 4914 } 4915 } 4916 if (matchres.vcount == 1) { 4917 req->sym_out = matchres.vsymp; 4918 req->defobj_out = obj; 4919 return (0); 4920 } 4921 return (ESRCH); 4922 } 4923 4924 /* Search for symbol using GNU hash function */ 4925 static int 4926 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4927 { 4928 Elf_Addr bloom_word; 4929 const Elf32_Word *hashval; 4930 Elf32_Word bucket; 4931 Sym_Match_Result matchres; 4932 unsigned int h1, h2; 4933 unsigned long symnum; 4934 4935 matchres.sym_out = NULL; 4936 matchres.vsymp = NULL; 4937 matchres.vcount = 0; 4938 4939 /* Pick right bitmask word from Bloom filter array */ 4940 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4941 obj->maskwords_bm_gnu]; 4942 4943 /* Calculate modulus word size of gnu hash and its derivative */ 4944 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4945 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4946 4947 /* Filter out the "definitely not in set" queries */ 4948 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4949 return (ESRCH); 4950 4951 /* Locate hash chain and corresponding value element*/ 4952 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4953 if (bucket == 0) 4954 return (ESRCH); 4955 hashval = &obj->chain_zero_gnu[bucket]; 4956 do { 4957 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4958 symnum = hashval - obj->chain_zero_gnu; 4959 if (matched_symbol(req, obj, &matchres, symnum)) { 4960 req->sym_out = matchres.sym_out; 4961 req->defobj_out = obj; 4962 return (0); 4963 } 4964 } 4965 } while ((*hashval++ & 1) == 0); 4966 if (matchres.vcount == 1) { 4967 req->sym_out = matchres.vsymp; 4968 req->defobj_out = obj; 4969 return (0); 4970 } 4971 return (ESRCH); 4972 } 4973 4974 static void 4975 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4976 { 4977 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4978 if (*main_local == NULL) 4979 *main_local = ""; 4980 4981 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4982 if (*fmt1 == NULL) 4983 *fmt1 = "\t%o => %p (%x)\n"; 4984 4985 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4986 if (*fmt2 == NULL) 4987 *fmt2 = "\t%o (%x)\n"; 4988 } 4989 4990 static void 4991 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4992 const char *main_local, const char *fmt1, const char *fmt2) 4993 { 4994 const char *fmt; 4995 int c; 4996 4997 if (fmt1 == NULL) 4998 fmt = fmt2; 4999 else 5000 /* XXX bogus */ 5001 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 5002 5003 while ((c = *fmt++) != '\0') { 5004 switch (c) { 5005 default: 5006 rtld_putchar(c); 5007 continue; 5008 case '\\': 5009 switch (c = *fmt) { 5010 case '\0': 5011 continue; 5012 case 'n': 5013 rtld_putchar('\n'); 5014 break; 5015 case 't': 5016 rtld_putchar('\t'); 5017 break; 5018 } 5019 break; 5020 case '%': 5021 switch (c = *fmt) { 5022 case '\0': 5023 continue; 5024 case '%': 5025 default: 5026 rtld_putchar(c); 5027 break; 5028 case 'A': 5029 rtld_putstr(main_local); 5030 break; 5031 case 'a': 5032 rtld_putstr(obj_main->path); 5033 break; 5034 case 'o': 5035 rtld_putstr(name); 5036 break; 5037 case 'p': 5038 rtld_putstr(path); 5039 break; 5040 case 'x': 5041 rtld_printf("%p", obj != NULL ? 5042 obj->mapbase : NULL); 5043 break; 5044 } 5045 break; 5046 } 5047 ++fmt; 5048 } 5049 } 5050 5051 static void 5052 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5053 { 5054 const char *fmt1, *fmt2, *main_local; 5055 const char *name, *path; 5056 bool first_spurious, list_containers; 5057 5058 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5059 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5060 5061 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5062 Needed_Entry *needed; 5063 5064 if (obj->marker) 5065 continue; 5066 if (list_containers && obj->needed != NULL) 5067 rtld_printf("%s:\n", obj->path); 5068 for (needed = obj->needed; needed; needed = needed->next) { 5069 if (needed->obj != NULL) { 5070 if (needed->obj->traced && !list_containers) 5071 continue; 5072 needed->obj->traced = true; 5073 path = needed->obj->path; 5074 } else 5075 path = "not found"; 5076 5077 name = obj->strtab + needed->name; 5078 trace_print_obj(needed->obj, name, path, main_local, 5079 fmt1, fmt2); 5080 } 5081 } 5082 5083 if (show_preload) { 5084 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5085 fmt2 = "\t%p (%x)\n"; 5086 first_spurious = true; 5087 5088 TAILQ_FOREACH(obj, &obj_list, next) { 5089 if (obj->marker || obj == obj_main || obj->traced) 5090 continue; 5091 5092 if (list_containers && first_spurious) { 5093 rtld_printf("[preloaded]\n"); 5094 first_spurious = false; 5095 } 5096 5097 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5098 name = fname == NULL ? "<unknown>" : fname->name; 5099 trace_print_obj(obj, name, obj->path, main_local, 5100 NULL, fmt2); 5101 } 5102 } 5103 } 5104 5105 /* 5106 * Unload a dlopened object and its dependencies from memory and from 5107 * our data structures. It is assumed that the DAG rooted in the 5108 * object has already been unreferenced, and that the object has a 5109 * reference count of 0. 5110 */ 5111 static void 5112 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5113 { 5114 Obj_Entry marker, *obj, *next; 5115 5116 assert(root->refcount == 0); 5117 5118 /* 5119 * Pass over the DAG removing unreferenced objects from 5120 * appropriate lists. 5121 */ 5122 unlink_object(root); 5123 5124 /* Unmap all objects that are no longer referenced. */ 5125 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5126 next = TAILQ_NEXT(obj, next); 5127 if (obj->marker || obj->refcount != 0) 5128 continue; 5129 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5130 obj->mapsize, 0, obj->path); 5131 dbg("unloading \"%s\"", obj->path); 5132 /* 5133 * Unlink the object now to prevent new references from 5134 * being acquired while the bind lock is dropped in 5135 * recursive dlclose() invocations. 5136 */ 5137 TAILQ_REMOVE(&obj_list, obj, next); 5138 obj_count--; 5139 5140 if (obj->filtees_loaded) { 5141 if (next != NULL) { 5142 init_marker(&marker); 5143 TAILQ_INSERT_BEFORE(next, &marker, next); 5144 unload_filtees(obj, lockstate); 5145 next = TAILQ_NEXT(&marker, next); 5146 TAILQ_REMOVE(&obj_list, &marker, next); 5147 } else 5148 unload_filtees(obj, lockstate); 5149 } 5150 release_object(obj); 5151 } 5152 } 5153 5154 static void 5155 unlink_object(Obj_Entry *root) 5156 { 5157 Objlist_Entry *elm; 5158 5159 if (root->refcount == 0) { 5160 /* Remove the object from the RTLD_GLOBAL list. */ 5161 objlist_remove(&list_global, root); 5162 5163 /* Remove the object from all objects' DAG lists. */ 5164 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5165 objlist_remove(&elm->obj->dldags, root); 5166 if (elm->obj != root) 5167 unlink_object(elm->obj); 5168 } 5169 } 5170 } 5171 5172 static void 5173 ref_dag(Obj_Entry *root) 5174 { 5175 Objlist_Entry *elm; 5176 5177 assert(root->dag_inited); 5178 STAILQ_FOREACH(elm, &root->dagmembers, link) 5179 elm->obj->refcount++; 5180 } 5181 5182 static void 5183 unref_dag(Obj_Entry *root) 5184 { 5185 Objlist_Entry *elm; 5186 5187 assert(root->dag_inited); 5188 STAILQ_FOREACH(elm, &root->dagmembers, link) 5189 elm->obj->refcount--; 5190 } 5191 5192 /* 5193 * Common code for MD __tls_get_addr(). 5194 */ 5195 static void * 5196 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5197 { 5198 Elf_Addr *newdtv, *dtv; 5199 RtldLockState lockstate; 5200 int to_copy; 5201 5202 dtv = *dtvp; 5203 /* Check dtv generation in case new modules have arrived */ 5204 if (dtv[0] != tls_dtv_generation) { 5205 if (!locked) 5206 wlock_acquire(rtld_bind_lock, &lockstate); 5207 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5208 to_copy = dtv[1]; 5209 if (to_copy > tls_max_index) 5210 to_copy = tls_max_index; 5211 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5212 newdtv[0] = tls_dtv_generation; 5213 newdtv[1] = tls_max_index; 5214 free(dtv); 5215 if (!locked) 5216 lock_release(rtld_bind_lock, &lockstate); 5217 dtv = *dtvp = newdtv; 5218 } 5219 5220 /* Dynamically allocate module TLS if necessary */ 5221 if (dtv[index + 1] == 0) { 5222 /* Signal safe, wlock will block out signals. */ 5223 if (!locked) 5224 wlock_acquire(rtld_bind_lock, &lockstate); 5225 if (!dtv[index + 1]) 5226 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5227 if (!locked) 5228 lock_release(rtld_bind_lock, &lockstate); 5229 } 5230 return ((void *)(dtv[index + 1] + offset)); 5231 } 5232 5233 void * 5234 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5235 { 5236 uintptr_t *dtv; 5237 5238 dtv = *dtvp; 5239 /* Check dtv generation in case new modules have arrived */ 5240 if (__predict_true(dtv[0] == tls_dtv_generation && 5241 dtv[index + 1] != 0)) 5242 return ((void *)(dtv[index + 1] + offset)); 5243 return (tls_get_addr_slow(dtvp, index, offset, false)); 5244 } 5245 5246 #ifdef TLS_VARIANT_I 5247 5248 /* 5249 * Return pointer to allocated TLS block 5250 */ 5251 static void * 5252 get_tls_block_ptr(void *tcb, size_t tcbsize) 5253 { 5254 size_t extra_size, post_size, pre_size, tls_block_size; 5255 size_t tls_init_align; 5256 5257 tls_init_align = MAX(obj_main->tlsalign, 1); 5258 5259 /* Compute fragments sizes. */ 5260 extra_size = tcbsize - TLS_TCB_SIZE; 5261 post_size = calculate_tls_post_size(tls_init_align); 5262 tls_block_size = tcbsize + post_size; 5263 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5264 5265 return ((char *)tcb - pre_size - extra_size); 5266 } 5267 5268 /* 5269 * Allocate Static TLS using the Variant I method. 5270 * 5271 * For details on the layout, see lib/libc/gen/tls.c. 5272 * 5273 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5274 * it is based on tls_last_offset, and TLS offsets here are really TCB 5275 * offsets, whereas libc's tls_static_space is just the executable's static 5276 * TLS segment. 5277 */ 5278 void * 5279 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5280 { 5281 Obj_Entry *obj; 5282 char *tls_block; 5283 Elf_Addr *dtv, **tcb; 5284 Elf_Addr addr; 5285 Elf_Addr i; 5286 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5287 size_t tls_init_align, tls_init_offset; 5288 5289 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5290 return (oldtcb); 5291 5292 assert(tcbsize >= TLS_TCB_SIZE); 5293 maxalign = MAX(tcbalign, tls_static_max_align); 5294 tls_init_align = MAX(obj_main->tlsalign, 1); 5295 5296 /* Compute fragmets sizes. */ 5297 extra_size = tcbsize - TLS_TCB_SIZE; 5298 post_size = calculate_tls_post_size(tls_init_align); 5299 tls_block_size = tcbsize + post_size; 5300 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5301 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5302 5303 /* Allocate whole TLS block */ 5304 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5305 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5306 5307 if (oldtcb != NULL) { 5308 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5309 tls_static_space); 5310 free(get_tls_block_ptr(oldtcb, tcbsize)); 5311 5312 /* Adjust the DTV. */ 5313 dtv = tcb[0]; 5314 for (i = 0; i < dtv[1]; i++) { 5315 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5316 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5317 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5318 } 5319 } 5320 } else { 5321 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5322 tcb[0] = dtv; 5323 dtv[0] = tls_dtv_generation; 5324 dtv[1] = tls_max_index; 5325 5326 for (obj = globallist_curr(objs); obj != NULL; 5327 obj = globallist_next(obj)) { 5328 if (obj->tlsoffset == 0) 5329 continue; 5330 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5331 addr = (Elf_Addr)tcb + obj->tlsoffset; 5332 if (tls_init_offset > 0) 5333 memset((void *)addr, 0, tls_init_offset); 5334 if (obj->tlsinitsize > 0) { 5335 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5336 obj->tlsinitsize); 5337 } 5338 if (obj->tlssize > obj->tlsinitsize) { 5339 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5340 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5341 } 5342 dtv[obj->tlsindex + 1] = addr; 5343 } 5344 } 5345 5346 return (tcb); 5347 } 5348 5349 void 5350 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5351 { 5352 Elf_Addr *dtv; 5353 Elf_Addr tlsstart, tlsend; 5354 size_t post_size; 5355 size_t dtvsize, i, tls_init_align __unused; 5356 5357 assert(tcbsize >= TLS_TCB_SIZE); 5358 tls_init_align = MAX(obj_main->tlsalign, 1); 5359 5360 /* Compute fragments sizes. */ 5361 post_size = calculate_tls_post_size(tls_init_align); 5362 5363 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5364 tlsend = (Elf_Addr)tcb + tls_static_space; 5365 5366 dtv = *(Elf_Addr **)tcb; 5367 dtvsize = dtv[1]; 5368 for (i = 0; i < dtvsize; i++) { 5369 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5370 free((void*)dtv[i+2]); 5371 } 5372 } 5373 free(dtv); 5374 free(get_tls_block_ptr(tcb, tcbsize)); 5375 } 5376 5377 #endif /* TLS_VARIANT_I */ 5378 5379 #ifdef TLS_VARIANT_II 5380 5381 /* 5382 * Allocate Static TLS using the Variant II method. 5383 */ 5384 void * 5385 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5386 { 5387 Obj_Entry *obj; 5388 size_t size, ralign; 5389 char *tls; 5390 Elf_Addr *dtv, *olddtv; 5391 Elf_Addr segbase, oldsegbase, addr; 5392 size_t i; 5393 5394 ralign = tcbalign; 5395 if (tls_static_max_align > ralign) 5396 ralign = tls_static_max_align; 5397 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5398 5399 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5400 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5401 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5402 5403 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5404 ((Elf_Addr *)segbase)[0] = segbase; 5405 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5406 5407 dtv[0] = tls_dtv_generation; 5408 dtv[1] = tls_max_index; 5409 5410 if (oldtls) { 5411 /* 5412 * Copy the static TLS block over whole. 5413 */ 5414 oldsegbase = (Elf_Addr) oldtls; 5415 memcpy((void *)(segbase - tls_static_space), 5416 (const void *)(oldsegbase - tls_static_space), 5417 tls_static_space); 5418 5419 /* 5420 * If any dynamic TLS blocks have been created tls_get_addr(), 5421 * move them over. 5422 */ 5423 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5424 for (i = 0; i < olddtv[1]; i++) { 5425 if (olddtv[i + 2] < oldsegbase - size || 5426 olddtv[i + 2] > oldsegbase) { 5427 dtv[i + 2] = olddtv[i + 2]; 5428 olddtv[i + 2] = 0; 5429 } 5430 } 5431 5432 /* 5433 * We assume that this block was the one we created with 5434 * allocate_initial_tls(). 5435 */ 5436 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5437 } else { 5438 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5439 if (obj->marker || obj->tlsoffset == 0) 5440 continue; 5441 addr = segbase - obj->tlsoffset; 5442 memset((void *)(addr + obj->tlsinitsize), 5443 0, obj->tlssize - obj->tlsinitsize); 5444 if (obj->tlsinit) { 5445 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5446 obj->static_tls_copied = true; 5447 } 5448 dtv[obj->tlsindex + 1] = addr; 5449 } 5450 } 5451 5452 return ((void *)segbase); 5453 } 5454 5455 void 5456 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5457 { 5458 Elf_Addr* dtv; 5459 size_t size, ralign; 5460 int dtvsize, i; 5461 Elf_Addr tlsstart, tlsend; 5462 5463 /* 5464 * Figure out the size of the initial TLS block so that we can 5465 * find stuff which ___tls_get_addr() allocated dynamically. 5466 */ 5467 ralign = tcbalign; 5468 if (tls_static_max_align > ralign) 5469 ralign = tls_static_max_align; 5470 size = roundup(tls_static_space, ralign); 5471 5472 dtv = ((Elf_Addr **)tls)[1]; 5473 dtvsize = dtv[1]; 5474 tlsend = (Elf_Addr)tls; 5475 tlsstart = tlsend - size; 5476 for (i = 0; i < dtvsize; i++) { 5477 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5478 dtv[i + 2] > tlsend)) { 5479 free((void *)dtv[i + 2]); 5480 } 5481 } 5482 5483 free((void *)tlsstart); 5484 free((void *)dtv); 5485 } 5486 5487 #endif /* TLS_VARIANT_II */ 5488 5489 /* 5490 * Allocate TLS block for module with given index. 5491 */ 5492 void * 5493 allocate_module_tls(int index) 5494 { 5495 Obj_Entry *obj; 5496 char *p; 5497 5498 TAILQ_FOREACH(obj, &obj_list, next) { 5499 if (obj->marker) 5500 continue; 5501 if (obj->tlsindex == index) 5502 break; 5503 } 5504 if (obj == NULL) { 5505 _rtld_error("Can't find module with TLS index %d", index); 5506 rtld_die(); 5507 } 5508 5509 if (obj->tls_static) { 5510 #ifdef TLS_VARIANT_I 5511 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5512 #else 5513 p = (char *)_tcb_get() - obj->tlsoffset; 5514 #endif 5515 return (p); 5516 } 5517 5518 obj->tls_dynamic = true; 5519 5520 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5521 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5522 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5523 return (p); 5524 } 5525 5526 bool 5527 allocate_tls_offset(Obj_Entry *obj) 5528 { 5529 size_t off; 5530 5531 if (obj->tls_dynamic) 5532 return (false); 5533 5534 if (obj->tls_static) 5535 return (true); 5536 5537 if (obj->tlssize == 0) { 5538 obj->tls_static = true; 5539 return (true); 5540 } 5541 5542 if (tls_last_offset == 0) 5543 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5544 obj->tlspoffset); 5545 else 5546 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5547 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5548 5549 obj->tlsoffset = off; 5550 #ifdef TLS_VARIANT_I 5551 off += obj->tlssize; 5552 #endif 5553 5554 /* 5555 * If we have already fixed the size of the static TLS block, we 5556 * must stay within that size. When allocating the static TLS, we 5557 * leave a small amount of space spare to be used for dynamically 5558 * loading modules which use static TLS. 5559 */ 5560 if (tls_static_space != 0) { 5561 if (off > tls_static_space) 5562 return (false); 5563 } else if (obj->tlsalign > tls_static_max_align) { 5564 tls_static_max_align = obj->tlsalign; 5565 } 5566 5567 tls_last_offset = off; 5568 tls_last_size = obj->tlssize; 5569 obj->tls_static = true; 5570 5571 return (true); 5572 } 5573 5574 void 5575 free_tls_offset(Obj_Entry *obj) 5576 { 5577 5578 /* 5579 * If we were the last thing to allocate out of the static TLS 5580 * block, we give our space back to the 'allocator'. This is a 5581 * simplistic workaround to allow libGL.so.1 to be loaded and 5582 * unloaded multiple times. 5583 */ 5584 size_t off = obj->tlsoffset; 5585 #ifdef TLS_VARIANT_I 5586 off += obj->tlssize; 5587 #endif 5588 if (off == tls_last_offset) { 5589 tls_last_offset -= obj->tlssize; 5590 tls_last_size = 0; 5591 } 5592 } 5593 5594 void * 5595 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5596 { 5597 void *ret; 5598 RtldLockState lockstate; 5599 5600 wlock_acquire(rtld_bind_lock, &lockstate); 5601 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5602 tcbsize, tcbalign); 5603 lock_release(rtld_bind_lock, &lockstate); 5604 return (ret); 5605 } 5606 5607 void 5608 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5609 { 5610 RtldLockState lockstate; 5611 5612 wlock_acquire(rtld_bind_lock, &lockstate); 5613 free_tls(tcb, tcbsize, tcbalign); 5614 lock_release(rtld_bind_lock, &lockstate); 5615 } 5616 5617 static void 5618 object_add_name(Obj_Entry *obj, const char *name) 5619 { 5620 Name_Entry *entry; 5621 size_t len; 5622 5623 len = strlen(name); 5624 entry = malloc(sizeof(Name_Entry) + len); 5625 5626 if (entry != NULL) { 5627 strcpy(entry->name, name); 5628 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5629 } 5630 } 5631 5632 static int 5633 object_match_name(const Obj_Entry *obj, const char *name) 5634 { 5635 Name_Entry *entry; 5636 5637 STAILQ_FOREACH(entry, &obj->names, link) { 5638 if (strcmp(name, entry->name) == 0) 5639 return (1); 5640 } 5641 return (0); 5642 } 5643 5644 static Obj_Entry * 5645 locate_dependency(const Obj_Entry *obj, const char *name) 5646 { 5647 const Objlist_Entry *entry; 5648 const Needed_Entry *needed; 5649 5650 STAILQ_FOREACH(entry, &list_main, link) { 5651 if (object_match_name(entry->obj, name)) 5652 return (entry->obj); 5653 } 5654 5655 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5656 if (strcmp(obj->strtab + needed->name, name) == 0 || 5657 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5658 /* 5659 * If there is DT_NEEDED for the name we are looking for, 5660 * we are all set. Note that object might not be found if 5661 * dependency was not loaded yet, so the function can 5662 * return NULL here. This is expected and handled 5663 * properly by the caller. 5664 */ 5665 return (needed->obj); 5666 } 5667 } 5668 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5669 obj->path, name); 5670 rtld_die(); 5671 } 5672 5673 static int 5674 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5675 const Elf_Vernaux *vna) 5676 { 5677 const Elf_Verdef *vd; 5678 const char *vername; 5679 5680 vername = refobj->strtab + vna->vna_name; 5681 vd = depobj->verdef; 5682 if (vd == NULL) { 5683 _rtld_error("%s: version %s required by %s not defined", 5684 depobj->path, vername, refobj->path); 5685 return (-1); 5686 } 5687 for (;;) { 5688 if (vd->vd_version != VER_DEF_CURRENT) { 5689 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5690 depobj->path, vd->vd_version); 5691 return (-1); 5692 } 5693 if (vna->vna_hash == vd->vd_hash) { 5694 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5695 ((const char *)vd + vd->vd_aux); 5696 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5697 return (0); 5698 } 5699 if (vd->vd_next == 0) 5700 break; 5701 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5702 } 5703 if (vna->vna_flags & VER_FLG_WEAK) 5704 return (0); 5705 _rtld_error("%s: version %s required by %s not found", 5706 depobj->path, vername, refobj->path); 5707 return (-1); 5708 } 5709 5710 static int 5711 rtld_verify_object_versions(Obj_Entry *obj) 5712 { 5713 const Elf_Verneed *vn; 5714 const Elf_Verdef *vd; 5715 const Elf_Verdaux *vda; 5716 const Elf_Vernaux *vna; 5717 const Obj_Entry *depobj; 5718 int maxvernum, vernum; 5719 5720 if (obj->ver_checked) 5721 return (0); 5722 obj->ver_checked = true; 5723 5724 maxvernum = 0; 5725 /* 5726 * Walk over defined and required version records and figure out 5727 * max index used by any of them. Do very basic sanity checking 5728 * while there. 5729 */ 5730 vn = obj->verneed; 5731 while (vn != NULL) { 5732 if (vn->vn_version != VER_NEED_CURRENT) { 5733 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5734 obj->path, vn->vn_version); 5735 return (-1); 5736 } 5737 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5738 for (;;) { 5739 vernum = VER_NEED_IDX(vna->vna_other); 5740 if (vernum > maxvernum) 5741 maxvernum = vernum; 5742 if (vna->vna_next == 0) 5743 break; 5744 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5745 } 5746 if (vn->vn_next == 0) 5747 break; 5748 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5749 } 5750 5751 vd = obj->verdef; 5752 while (vd != NULL) { 5753 if (vd->vd_version != VER_DEF_CURRENT) { 5754 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5755 obj->path, vd->vd_version); 5756 return (-1); 5757 } 5758 vernum = VER_DEF_IDX(vd->vd_ndx); 5759 if (vernum > maxvernum) 5760 maxvernum = vernum; 5761 if (vd->vd_next == 0) 5762 break; 5763 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5764 } 5765 5766 if (maxvernum == 0) 5767 return (0); 5768 5769 /* 5770 * Store version information in array indexable by version index. 5771 * Verify that object version requirements are satisfied along the 5772 * way. 5773 */ 5774 obj->vernum = maxvernum + 1; 5775 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5776 5777 vd = obj->verdef; 5778 while (vd != NULL) { 5779 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5780 vernum = VER_DEF_IDX(vd->vd_ndx); 5781 assert(vernum <= maxvernum); 5782 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5783 obj->vertab[vernum].hash = vd->vd_hash; 5784 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5785 obj->vertab[vernum].file = NULL; 5786 obj->vertab[vernum].flags = 0; 5787 } 5788 if (vd->vd_next == 0) 5789 break; 5790 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5791 } 5792 5793 vn = obj->verneed; 5794 while (vn != NULL) { 5795 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5796 if (depobj == NULL) 5797 return (-1); 5798 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5799 for (;;) { 5800 if (check_object_provided_version(obj, depobj, vna)) 5801 return (-1); 5802 vernum = VER_NEED_IDX(vna->vna_other); 5803 assert(vernum <= maxvernum); 5804 obj->vertab[vernum].hash = vna->vna_hash; 5805 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5806 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5807 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5808 VER_INFO_HIDDEN : 0; 5809 if (vna->vna_next == 0) 5810 break; 5811 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5812 } 5813 if (vn->vn_next == 0) 5814 break; 5815 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5816 } 5817 return (0); 5818 } 5819 5820 static int 5821 rtld_verify_versions(const Objlist *objlist) 5822 { 5823 Objlist_Entry *entry; 5824 int rc; 5825 5826 rc = 0; 5827 STAILQ_FOREACH(entry, objlist, link) { 5828 /* 5829 * Skip dummy objects or objects that have their version requirements 5830 * already checked. 5831 */ 5832 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5833 continue; 5834 if (rtld_verify_object_versions(entry->obj) == -1) { 5835 rc = -1; 5836 if (ld_tracing == NULL) 5837 break; 5838 } 5839 } 5840 if (rc == 0 || ld_tracing != NULL) 5841 rc = rtld_verify_object_versions(&obj_rtld); 5842 return (rc); 5843 } 5844 5845 const Ver_Entry * 5846 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5847 { 5848 Elf_Versym vernum; 5849 5850 if (obj->vertab) { 5851 vernum = VER_NDX(obj->versyms[symnum]); 5852 if (vernum >= obj->vernum) { 5853 _rtld_error("%s: symbol %s has wrong verneed value %d", 5854 obj->path, obj->strtab + symnum, vernum); 5855 } else if (obj->vertab[vernum].hash != 0) { 5856 return (&obj->vertab[vernum]); 5857 } 5858 } 5859 return (NULL); 5860 } 5861 5862 int 5863 _rtld_get_stack_prot(void) 5864 { 5865 5866 return (stack_prot); 5867 } 5868 5869 int 5870 _rtld_is_dlopened(void *arg) 5871 { 5872 Obj_Entry *obj; 5873 RtldLockState lockstate; 5874 int res; 5875 5876 rlock_acquire(rtld_bind_lock, &lockstate); 5877 obj = dlcheck(arg); 5878 if (obj == NULL) 5879 obj = obj_from_addr(arg); 5880 if (obj == NULL) { 5881 _rtld_error("No shared object contains address"); 5882 lock_release(rtld_bind_lock, &lockstate); 5883 return (-1); 5884 } 5885 res = obj->dlopened ? 1 : 0; 5886 lock_release(rtld_bind_lock, &lockstate); 5887 return (res); 5888 } 5889 5890 static int 5891 obj_remap_relro(Obj_Entry *obj, int prot) 5892 { 5893 5894 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5895 prot) == -1) { 5896 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5897 obj->path, prot, rtld_strerror(errno)); 5898 return (-1); 5899 } 5900 return (0); 5901 } 5902 5903 static int 5904 obj_disable_relro(Obj_Entry *obj) 5905 { 5906 5907 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5908 } 5909 5910 static int 5911 obj_enforce_relro(Obj_Entry *obj) 5912 { 5913 5914 return (obj_remap_relro(obj, PROT_READ)); 5915 } 5916 5917 static void 5918 map_stacks_exec(RtldLockState *lockstate) 5919 { 5920 void (*thr_map_stacks_exec)(void); 5921 5922 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5923 return; 5924 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5925 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5926 if (thr_map_stacks_exec != NULL) { 5927 stack_prot |= PROT_EXEC; 5928 thr_map_stacks_exec(); 5929 } 5930 } 5931 5932 static void 5933 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5934 { 5935 Objlist_Entry *elm; 5936 Obj_Entry *obj; 5937 void (*distrib)(size_t, void *, size_t, size_t); 5938 5939 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5940 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5941 if (distrib == NULL) 5942 return; 5943 STAILQ_FOREACH(elm, list, link) { 5944 obj = elm->obj; 5945 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5946 continue; 5947 lock_release(rtld_bind_lock, lockstate); 5948 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5949 obj->tlssize); 5950 wlock_acquire(rtld_bind_lock, lockstate); 5951 obj->static_tls_copied = true; 5952 } 5953 } 5954 5955 void 5956 symlook_init(SymLook *dst, const char *name) 5957 { 5958 5959 bzero(dst, sizeof(*dst)); 5960 dst->name = name; 5961 dst->hash = elf_hash(name); 5962 dst->hash_gnu = gnu_hash(name); 5963 } 5964 5965 static void 5966 symlook_init_from_req(SymLook *dst, const SymLook *src) 5967 { 5968 5969 dst->name = src->name; 5970 dst->hash = src->hash; 5971 dst->hash_gnu = src->hash_gnu; 5972 dst->ventry = src->ventry; 5973 dst->flags = src->flags; 5974 dst->defobj_out = NULL; 5975 dst->sym_out = NULL; 5976 dst->lockstate = src->lockstate; 5977 } 5978 5979 static int 5980 open_binary_fd(const char *argv0, bool search_in_path, 5981 const char **binpath_res) 5982 { 5983 char *binpath, *pathenv, *pe, *res1; 5984 const char *res; 5985 int fd; 5986 5987 binpath = NULL; 5988 res = NULL; 5989 if (search_in_path && strchr(argv0, '/') == NULL) { 5990 binpath = xmalloc(PATH_MAX); 5991 pathenv = getenv("PATH"); 5992 if (pathenv == NULL) { 5993 _rtld_error("-p and no PATH environment variable"); 5994 rtld_die(); 5995 } 5996 pathenv = strdup(pathenv); 5997 if (pathenv == NULL) { 5998 _rtld_error("Cannot allocate memory"); 5999 rtld_die(); 6000 } 6001 fd = -1; 6002 errno = ENOENT; 6003 while ((pe = strsep(&pathenv, ":")) != NULL) { 6004 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 6005 continue; 6006 if (binpath[0] != '\0' && 6007 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 6008 continue; 6009 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 6010 continue; 6011 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 6012 if (fd != -1 || errno != ENOENT) { 6013 res = binpath; 6014 break; 6015 } 6016 } 6017 free(pathenv); 6018 } else { 6019 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 6020 res = argv0; 6021 } 6022 6023 if (fd == -1) { 6024 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 6025 rtld_die(); 6026 } 6027 if (res != NULL && res[0] != '/') { 6028 res1 = xmalloc(PATH_MAX); 6029 if (realpath(res, res1) != NULL) { 6030 if (res != argv0) 6031 free(__DECONST(char *, res)); 6032 res = res1; 6033 } else { 6034 free(res1); 6035 } 6036 } 6037 *binpath_res = res; 6038 return (fd); 6039 } 6040 6041 /* 6042 * Parse a set of command-line arguments. 6043 */ 6044 static int 6045 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6046 const char **argv0, bool *dir_ignore) 6047 { 6048 const char *arg; 6049 char machine[64]; 6050 size_t sz; 6051 int arglen, fd, i, j, mib[2]; 6052 char opt; 6053 bool seen_b, seen_f; 6054 6055 dbg("Parsing command-line arguments"); 6056 *use_pathp = false; 6057 *fdp = -1; 6058 *dir_ignore = false; 6059 seen_b = seen_f = false; 6060 6061 for (i = 1; i < argc; i++ ) { 6062 arg = argv[i]; 6063 dbg("argv[%d]: '%s'", i, arg); 6064 6065 /* 6066 * rtld arguments end with an explicit "--" or with the first 6067 * non-prefixed argument. 6068 */ 6069 if (strcmp(arg, "--") == 0) { 6070 i++; 6071 break; 6072 } 6073 if (arg[0] != '-') 6074 break; 6075 6076 /* 6077 * All other arguments are single-character options that can 6078 * be combined, so we need to search through `arg` for them. 6079 */ 6080 arglen = strlen(arg); 6081 for (j = 1; j < arglen; j++) { 6082 opt = arg[j]; 6083 if (opt == 'h') { 6084 print_usage(argv[0]); 6085 _exit(0); 6086 } else if (opt == 'b') { 6087 if (seen_f) { 6088 _rtld_error("Both -b and -f specified"); 6089 rtld_die(); 6090 } 6091 if (j != arglen - 1) { 6092 _rtld_error("Invalid options: %s", arg); 6093 rtld_die(); 6094 } 6095 i++; 6096 *argv0 = argv[i]; 6097 seen_b = true; 6098 break; 6099 } else if (opt == 'd') { 6100 *dir_ignore = true; 6101 } else if (opt == 'f') { 6102 if (seen_b) { 6103 _rtld_error("Both -b and -f specified"); 6104 rtld_die(); 6105 } 6106 6107 /* 6108 * -f XX can be used to specify a 6109 * descriptor for the binary named at 6110 * the command line (i.e., the later 6111 * argument will specify the process 6112 * name but the descriptor is what 6113 * will actually be executed). 6114 * 6115 * -f must be the last option in the 6116 * group, e.g., -abcf <fd>. 6117 */ 6118 if (j != arglen - 1) { 6119 _rtld_error("Invalid options: %s", arg); 6120 rtld_die(); 6121 } 6122 i++; 6123 fd = parse_integer(argv[i]); 6124 if (fd == -1) { 6125 _rtld_error( 6126 "Invalid file descriptor: '%s'", 6127 argv[i]); 6128 rtld_die(); 6129 } 6130 *fdp = fd; 6131 seen_f = true; 6132 break; 6133 } else if (opt == 'o') { 6134 struct ld_env_var_desc *l; 6135 char *n, *v; 6136 u_int ll; 6137 6138 if (j != arglen - 1) { 6139 _rtld_error("Invalid options: %s", arg); 6140 rtld_die(); 6141 } 6142 i++; 6143 n = argv[i]; 6144 v = strchr(n, '='); 6145 if (v == NULL) { 6146 _rtld_error("No '=' in -o parameter"); 6147 rtld_die(); 6148 } 6149 for (ll = 0; ll < nitems(ld_env_vars); ll++) { 6150 l = &ld_env_vars[ll]; 6151 if (v - n == (ptrdiff_t)strlen(l->n) && 6152 strncmp(n, l->n, v - n) == 0) { 6153 l->val = v + 1; 6154 break; 6155 } 6156 } 6157 if (ll == nitems(ld_env_vars)) { 6158 _rtld_error("Unknown LD_ option %s", 6159 n); 6160 rtld_die(); 6161 } 6162 } else if (opt == 'p') { 6163 *use_pathp = true; 6164 } else if (opt == 'u') { 6165 u_int ll; 6166 6167 for (ll = 0; ll < nitems(ld_env_vars); ll++) 6168 ld_env_vars[ll].val = NULL; 6169 } else if (opt == 'v') { 6170 machine[0] = '\0'; 6171 mib[0] = CTL_HW; 6172 mib[1] = HW_MACHINE; 6173 sz = sizeof(machine); 6174 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6175 ld_elf_hints_path = ld_get_env_var( 6176 LD_ELF_HINTS_PATH); 6177 set_ld_elf_hints_path(); 6178 rtld_printf( 6179 "FreeBSD ld-elf.so.1 %s\n" 6180 "FreeBSD_version %d\n" 6181 "Default lib path %s\n" 6182 "Hints lib path %s\n" 6183 "Env prefix %s\n" 6184 "Default hint file %s\n" 6185 "Hint file %s\n" 6186 "libmap file %s\n" 6187 "Optional static TLS size %zd bytes\n", 6188 machine, 6189 __FreeBSD_version, ld_standard_library_path, 6190 gethints(false), 6191 ld_env_prefix, ld_elf_hints_default, 6192 ld_elf_hints_path, 6193 ld_path_libmap_conf, 6194 ld_static_tls_extra); 6195 _exit(0); 6196 } else { 6197 _rtld_error("Invalid argument: '%s'", arg); 6198 print_usage(argv[0]); 6199 rtld_die(); 6200 } 6201 } 6202 } 6203 6204 if (!seen_b) 6205 *argv0 = argv[i]; 6206 return (i); 6207 } 6208 6209 /* 6210 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6211 */ 6212 static int 6213 parse_integer(const char *str) 6214 { 6215 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6216 const char *orig; 6217 int n; 6218 char c; 6219 6220 orig = str; 6221 n = 0; 6222 for (c = *str; c != '\0'; c = *++str) { 6223 if (c < '0' || c > '9') 6224 return (-1); 6225 6226 n *= RADIX; 6227 n += c - '0'; 6228 } 6229 6230 /* Make sure we actually parsed something. */ 6231 if (str == orig) 6232 return (-1); 6233 return (n); 6234 } 6235 6236 static void 6237 print_usage(const char *argv0) 6238 { 6239 6240 rtld_printf( 6241 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6242 "\n" 6243 "Options:\n" 6244 " -h Display this help message\n" 6245 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6246 " -d Ignore lack of exec permissions for the binary\n" 6247 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6248 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n" 6249 " -p Search in PATH for named binary\n" 6250 " -u Ignore LD_ environment variables\n" 6251 " -v Display identification information\n" 6252 " -- End of RTLD options\n" 6253 " <binary> Name of process to execute\n" 6254 " <args> Arguments to the executed process\n", argv0); 6255 } 6256 6257 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6258 static const struct auxfmt { 6259 const char *name; 6260 const char *fmt; 6261 } auxfmts[] = { 6262 AUXFMT(AT_NULL, NULL), 6263 AUXFMT(AT_IGNORE, NULL), 6264 AUXFMT(AT_EXECFD, "%ld"), 6265 AUXFMT(AT_PHDR, "%p"), 6266 AUXFMT(AT_PHENT, "%lu"), 6267 AUXFMT(AT_PHNUM, "%lu"), 6268 AUXFMT(AT_PAGESZ, "%lu"), 6269 AUXFMT(AT_BASE, "%#lx"), 6270 AUXFMT(AT_FLAGS, "%#lx"), 6271 AUXFMT(AT_ENTRY, "%p"), 6272 AUXFMT(AT_NOTELF, NULL), 6273 AUXFMT(AT_UID, "%ld"), 6274 AUXFMT(AT_EUID, "%ld"), 6275 AUXFMT(AT_GID, "%ld"), 6276 AUXFMT(AT_EGID, "%ld"), 6277 AUXFMT(AT_EXECPATH, "%s"), 6278 AUXFMT(AT_CANARY, "%p"), 6279 AUXFMT(AT_CANARYLEN, "%lu"), 6280 AUXFMT(AT_OSRELDATE, "%lu"), 6281 AUXFMT(AT_NCPUS, "%lu"), 6282 AUXFMT(AT_PAGESIZES, "%p"), 6283 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6284 AUXFMT(AT_TIMEKEEP, "%p"), 6285 AUXFMT(AT_STACKPROT, "%#lx"), 6286 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6287 AUXFMT(AT_HWCAP, "%#lx"), 6288 AUXFMT(AT_HWCAP2, "%#lx"), 6289 AUXFMT(AT_BSDFLAGS, "%#lx"), 6290 AUXFMT(AT_ARGC, "%lu"), 6291 AUXFMT(AT_ARGV, "%p"), 6292 AUXFMT(AT_ENVC, "%p"), 6293 AUXFMT(AT_ENVV, "%p"), 6294 AUXFMT(AT_PS_STRINGS, "%p"), 6295 AUXFMT(AT_FXRNG, "%p"), 6296 AUXFMT(AT_KPRELOAD, "%p"), 6297 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6298 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6299 }; 6300 6301 static bool 6302 is_ptr_fmt(const char *fmt) 6303 { 6304 char last; 6305 6306 last = fmt[strlen(fmt) - 1]; 6307 return (last == 'p' || last == 's'); 6308 } 6309 6310 static void 6311 dump_auxv(Elf_Auxinfo **aux_info) 6312 { 6313 Elf_Auxinfo *auxp; 6314 const struct auxfmt *fmt; 6315 int i; 6316 6317 for (i = 0; i < AT_COUNT; i++) { 6318 auxp = aux_info[i]; 6319 if (auxp == NULL) 6320 continue; 6321 fmt = &auxfmts[i]; 6322 if (fmt->fmt == NULL) 6323 continue; 6324 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6325 if (is_ptr_fmt(fmt->fmt)) { 6326 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6327 auxp->a_un.a_ptr); 6328 } else { 6329 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6330 auxp->a_un.a_val); 6331 } 6332 rtld_fdprintf(STDOUT_FILENO, "\n"); 6333 } 6334 } 6335 6336 /* 6337 * Overrides for libc_pic-provided functions. 6338 */ 6339 6340 int 6341 __getosreldate(void) 6342 { 6343 size_t len; 6344 int oid[2]; 6345 int error, osrel; 6346 6347 if (osreldate != 0) 6348 return (osreldate); 6349 6350 oid[0] = CTL_KERN; 6351 oid[1] = KERN_OSRELDATE; 6352 osrel = 0; 6353 len = sizeof(osrel); 6354 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6355 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6356 osreldate = osrel; 6357 return (osreldate); 6358 } 6359 const char * 6360 rtld_strerror(int errnum) 6361 { 6362 6363 if (errnum < 0 || errnum >= sys_nerr) 6364 return ("Unknown error"); 6365 return (sys_errlist[errnum]); 6366 } 6367 6368 char * 6369 getenv(const char *name) 6370 { 6371 return (__DECONST(char *, rtld_get_env_val(environ, name, 6372 strlen(name)))); 6373 } 6374 6375 /* malloc */ 6376 void * 6377 malloc(size_t nbytes) 6378 { 6379 6380 return (__crt_malloc(nbytes)); 6381 } 6382 6383 void * 6384 calloc(size_t num, size_t size) 6385 { 6386 6387 return (__crt_calloc(num, size)); 6388 } 6389 6390 void 6391 free(void *cp) 6392 { 6393 6394 __crt_free(cp); 6395 } 6396 6397 void * 6398 realloc(void *cp, size_t nbytes) 6399 { 6400 6401 return (__crt_realloc(cp, nbytes)); 6402 } 6403 6404 extern int _rtld_version__FreeBSD_version __exported; 6405 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6406 6407 extern char _rtld_version_laddr_offset __exported; 6408 char _rtld_version_laddr_offset; 6409 6410 extern char _rtld_version_dlpi_tls_data __exported; 6411 char _rtld_version_dlpi_tls_data; 6412