1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 50 #include <dlfcn.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "debug.h" 61 #include "rtld.h" 62 #include "libmap.h" 63 #include "rtld_paths.h" 64 #include "rtld_tls.h" 65 #include "rtld_printf.h" 66 #include "rtld_malloc.h" 67 #include "rtld_utrace.h" 68 #include "notes.h" 69 #include "rtld_libc.h" 70 71 /* Types. */ 72 typedef void (*func_ptr_type)(void); 73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 74 75 76 /* Variables that cannot be static: */ 77 extern struct r_debug r_debug; /* For GDB */ 78 extern int _thread_autoinit_dummy_decl; 79 extern void (*__cleanup)(void); 80 81 struct dlerror_save { 82 int seen; 83 char *msg; 84 }; 85 86 /* 87 * Function declarations. 88 */ 89 static const char *basename(const char *); 90 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 91 const Elf_Dyn **, const Elf_Dyn **); 92 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 93 const Elf_Dyn *); 94 static bool digest_dynamic(Obj_Entry *, int); 95 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 96 static void distribute_static_tls(Objlist *, RtldLockState *); 97 static Obj_Entry *dlcheck(void *); 98 static int dlclose_locked(void *, RtldLockState *); 99 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 100 int lo_flags, int mode, RtldLockState *lockstate); 101 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 102 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 103 static bool donelist_check(DoneList *, const Obj_Entry *); 104 static void dump_auxv(Elf_Auxinfo **aux_info); 105 static void errmsg_restore(struct dlerror_save *); 106 static struct dlerror_save *errmsg_save(void); 107 static void *fill_search_info(const char *, size_t, void *); 108 static char *find_library(const char *, const Obj_Entry *, int *); 109 static const char *gethints(bool); 110 static void hold_object(Obj_Entry *); 111 static void unhold_object(Obj_Entry *); 112 static void init_dag(Obj_Entry *); 113 static void init_marker(Obj_Entry *); 114 static void init_pagesizes(Elf_Auxinfo **aux_info); 115 static void init_rtld(caddr_t, Elf_Auxinfo **); 116 static void initlist_add_neededs(Needed_Entry *, Objlist *); 117 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 118 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 119 static void linkmap_add(Obj_Entry *); 120 static void linkmap_delete(Obj_Entry *); 121 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 122 static void unload_filtees(Obj_Entry *, RtldLockState *); 123 static int load_needed_objects(Obj_Entry *, int); 124 static int load_preload_objects(const char *, bool); 125 static int load_kpreload(const void *addr); 126 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 127 static void map_stacks_exec(RtldLockState *); 128 static int obj_disable_relro(Obj_Entry *); 129 static int obj_enforce_relro(Obj_Entry *); 130 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 131 static void objlist_call_init(Objlist *, RtldLockState *); 132 static void objlist_clear(Objlist *); 133 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 134 static void objlist_init(Objlist *); 135 static void objlist_push_head(Objlist *, Obj_Entry *); 136 static void objlist_push_tail(Objlist *, Obj_Entry *); 137 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 138 static void objlist_remove(Objlist *, Obj_Entry *); 139 static int open_binary_fd(const char *argv0, bool search_in_path, 140 const char **binpath_res); 141 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 142 const char **argv0, bool *dir_ignore); 143 static int parse_integer(const char *); 144 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 145 static void print_usage(const char *argv0); 146 static void release_object(Obj_Entry *); 147 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 148 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 149 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 150 int flags, RtldLockState *lockstate); 151 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 152 RtldLockState *); 153 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 154 static int rtld_dirname(const char *, char *); 155 static int rtld_dirname_abs(const char *, char *); 156 static void *rtld_dlopen(const char *name, int fd, int mode); 157 static void rtld_exit(void); 158 static void rtld_nop_exit(void); 159 static char *search_library_path(const char *, const char *, const char *, 160 int *); 161 static char *search_library_pathfds(const char *, const char *, int *); 162 static const void **get_program_var_addr(const char *, RtldLockState *); 163 static void set_program_var(const char *, const void *); 164 static int symlook_default(SymLook *, const Obj_Entry *refobj); 165 static int symlook_global(SymLook *, DoneList *); 166 static void symlook_init_from_req(SymLook *, const SymLook *); 167 static int symlook_list(SymLook *, const Objlist *, DoneList *); 168 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 169 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 170 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 171 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 172 static void trace_loaded_objects(Obj_Entry *, bool); 173 static void unlink_object(Obj_Entry *); 174 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 175 static void unref_dag(Obj_Entry *); 176 static void ref_dag(Obj_Entry *); 177 static char *origin_subst_one(Obj_Entry *, char *, const char *, 178 const char *, bool); 179 static char *origin_subst(Obj_Entry *, const char *); 180 static bool obj_resolve_origin(Obj_Entry *obj); 181 static void preinit_main(void); 182 static int rtld_verify_versions(const Objlist *); 183 static int rtld_verify_object_versions(Obj_Entry *); 184 static void object_add_name(Obj_Entry *, const char *); 185 static int object_match_name(const Obj_Entry *, const char *); 186 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 187 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 188 struct dl_phdr_info *phdr_info); 189 static uint32_t gnu_hash(const char *); 190 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 191 const unsigned long); 192 193 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 194 void _r_debug_postinit(struct link_map *) __noinline __exported; 195 196 int __sys_openat(int, const char *, int, ...); 197 198 /* 199 * Data declarations. 200 */ 201 struct r_debug r_debug __exported; /* for GDB; */ 202 static bool libmap_disable; /* Disable libmap */ 203 static bool ld_loadfltr; /* Immediate filters processing */ 204 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 205 static bool trust; /* False for setuid and setgid programs */ 206 static bool dangerous_ld_env; /* True if environment variables have been 207 used to affect the libraries loaded */ 208 bool ld_bind_not; /* Disable PLT update */ 209 static const char *ld_bind_now; /* Environment variable for immediate binding */ 210 static const char *ld_debug; /* Environment variable for debugging */ 211 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 212 weak definition */ 213 static const char *ld_library_path;/* Environment variable for search path */ 214 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 215 static const char *ld_preload; /* Environment variable for libraries to 216 load first */ 217 static const char *ld_preload_fds;/* Environment variable for libraries represented by 218 descriptors */ 219 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 220 static const char *ld_tracing; /* Called from ldd to print libs */ 221 static const char *ld_utrace; /* Use utrace() to log events. */ 222 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 223 static Obj_Entry *obj_main; /* The main program shared object */ 224 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 225 static unsigned int obj_count; /* Number of objects in obj_list */ 226 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 227 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */ 228 RTLD_STATIC_TLS_EXTRA; 229 230 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 231 STAILQ_HEAD_INITIALIZER(list_global); 232 static Objlist list_main = /* Objects loaded at program startup */ 233 STAILQ_HEAD_INITIALIZER(list_main); 234 static Objlist list_fini = /* Objects needing fini() calls */ 235 STAILQ_HEAD_INITIALIZER(list_fini); 236 237 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 238 239 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 240 241 extern Elf_Dyn _DYNAMIC; 242 #pragma weak _DYNAMIC 243 244 int dlclose(void *) __exported; 245 char *dlerror(void) __exported; 246 void *dlopen(const char *, int) __exported; 247 void *fdlopen(int, int) __exported; 248 void *dlsym(void *, const char *) __exported; 249 dlfunc_t dlfunc(void *, const char *) __exported; 250 void *dlvsym(void *, const char *, const char *) __exported; 251 int dladdr(const void *, Dl_info *) __exported; 252 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 253 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 254 int dlinfo(void *, int , void *) __exported; 255 int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback, 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 const char *rtld_get_var(const char *name) __exported; 262 int rtld_set_var(const char *name, const char *val) __exported; 263 264 /* Only here to fix -Wmissing-prototypes warnings */ 265 int __getosreldate(void); 266 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 267 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 268 269 int npagesizes; 270 static int osreldate; 271 size_t *pagesizes; 272 size_t page_size; 273 274 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; 275 static int max_stack_flags; 276 277 /* 278 * Global declarations normally provided by crt1. The dynamic linker is 279 * not built with crt1, so we have to provide them ourselves. 280 */ 281 char *__progname; 282 char **environ; 283 284 /* 285 * Used to pass argc, argv to init functions. 286 */ 287 int main_argc; 288 char **main_argv; 289 290 /* 291 * Globals to control TLS allocation. 292 */ 293 size_t tls_last_offset; /* Static TLS offset of last module */ 294 size_t tls_last_size; /* Static TLS size of last module */ 295 size_t tls_static_space; /* Static TLS space allocated */ 296 static size_t tls_static_max_align; 297 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 298 int tls_max_index = 1; /* Largest module index allocated */ 299 300 static bool ld_library_path_rpath = false; 301 bool ld_fast_sigblock = false; 302 303 /* 304 * Globals for path names, and such 305 */ 306 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 307 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 308 const char *ld_path_rtld = _PATH_RTLD; 309 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 310 const char *ld_env_prefix = LD_; 311 312 static void (*rtld_exit_ptr)(void); 313 314 /* 315 * Fill in a DoneList with an allocation large enough to hold all of 316 * the currently-loaded objects. Keep this as a macro since it calls 317 * alloca and we want that to occur within the scope of the caller. 318 */ 319 #define donelist_init(dlp) \ 320 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 321 assert((dlp)->objs != NULL), \ 322 (dlp)->num_alloc = obj_count, \ 323 (dlp)->num_used = 0) 324 325 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 326 if (ld_utrace != NULL) \ 327 ld_utrace_log(e, h, mb, ms, r, n); \ 328 } while (0) 329 330 static void 331 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 332 int refcnt, const char *name) 333 { 334 struct utrace_rtld ut; 335 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 336 337 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 338 ut.event = event; 339 ut.handle = handle; 340 ut.mapbase = mapbase; 341 ut.mapsize = mapsize; 342 ut.refcnt = refcnt; 343 bzero(ut.name, sizeof(ut.name)); 344 if (name) 345 strlcpy(ut.name, name, sizeof(ut.name)); 346 utrace(&ut, sizeof(ut)); 347 } 348 349 struct ld_env_var_desc { 350 const char * const n; 351 const char *val; 352 const bool unsecure:1; 353 const bool can_update:1; 354 const bool debug:1; 355 bool owned:1; 356 }; 357 #define LD_ENV_DESC(var, unsec, ...) \ 358 [LD_##var] = { \ 359 .n = #var, \ 360 .unsecure = unsec, \ 361 __VA_ARGS__ \ 362 } 363 364 static struct ld_env_var_desc ld_env_vars[] = { 365 LD_ENV_DESC(BIND_NOW, false), 366 LD_ENV_DESC(PRELOAD, true), 367 LD_ENV_DESC(LIBMAP, true), 368 LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true), 369 LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true), 370 LD_ENV_DESC(LIBMAP_DISABLE, true), 371 LD_ENV_DESC(BIND_NOT, true), 372 LD_ENV_DESC(DEBUG, true, .can_update = true, .debug = true), 373 LD_ENV_DESC(ELF_HINTS_PATH, true), 374 LD_ENV_DESC(LOADFLTR, true), 375 LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true), 376 LD_ENV_DESC(PRELOAD_FDS, true), 377 LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true), 378 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 379 LD_ENV_DESC(UTRACE, false, .can_update = true), 380 LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true), 381 LD_ENV_DESC(DUMP_REL_POST, false, .can_update = true), 382 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 383 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 384 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 385 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 386 LD_ENV_DESC(SHOW_AUXV, false), 387 LD_ENV_DESC(STATIC_TLS_EXTRA, false), 388 LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false), 389 }; 390 391 const char * 392 ld_get_env_var(int idx) 393 { 394 return (ld_env_vars[idx].val); 395 } 396 397 static const char * 398 rtld_get_env_val(char **env, const char *name, size_t name_len) 399 { 400 char **m, *n, *v; 401 402 for (m = env; *m != NULL; m++) { 403 n = *m; 404 v = strchr(n, '='); 405 if (v == NULL) { 406 /* corrupt environment? */ 407 continue; 408 } 409 if (v - n == (ptrdiff_t)name_len && 410 strncmp(name, n, name_len) == 0) 411 return (v + 1); 412 } 413 return (NULL); 414 } 415 416 static void 417 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 418 { 419 struct ld_env_var_desc *lvd; 420 size_t prefix_len, nlen; 421 char **m, *n, *v; 422 int i; 423 424 prefix_len = strlen(env_prefix); 425 for (m = env; *m != NULL; m++) { 426 n = *m; 427 if (strncmp(env_prefix, n, prefix_len) != 0) { 428 /* Not a rtld environment variable. */ 429 continue; 430 } 431 n += prefix_len; 432 v = strchr(n, '='); 433 if (v == NULL) { 434 /* corrupt environment? */ 435 continue; 436 } 437 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 438 lvd = &ld_env_vars[i]; 439 if (lvd->val != NULL) { 440 /* Saw higher-priority variable name already. */ 441 continue; 442 } 443 nlen = strlen(lvd->n); 444 if (v - n == (ptrdiff_t)nlen && 445 strncmp(lvd->n, n, nlen) == 0) { 446 lvd->val = v + 1; 447 break; 448 } 449 } 450 } 451 } 452 453 static void 454 rtld_init_env_vars(char **env) 455 { 456 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 457 } 458 459 static void 460 set_ld_elf_hints_path(void) 461 { 462 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 463 ld_elf_hints_path = ld_elf_hints_default; 464 } 465 466 uintptr_t 467 rtld_round_page(uintptr_t x) 468 { 469 return (roundup2(x, page_size)); 470 } 471 472 uintptr_t 473 rtld_trunc_page(uintptr_t x) 474 { 475 return (rounddown2(x, page_size)); 476 } 477 478 /* 479 * Main entry point for dynamic linking. The first argument is the 480 * stack pointer. The stack is expected to be laid out as described 481 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 482 * Specifically, the stack pointer points to a word containing 483 * ARGC. Following that in the stack is a null-terminated sequence 484 * of pointers to argument strings. Then comes a null-terminated 485 * sequence of pointers to environment strings. Finally, there is a 486 * sequence of "auxiliary vector" entries. 487 * 488 * The second argument points to a place to store the dynamic linker's 489 * exit procedure pointer and the third to a place to store the main 490 * program's object. 491 * 492 * The return value is the main program's entry point. 493 */ 494 func_ptr_type 495 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 496 { 497 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 498 Objlist_Entry *entry; 499 Obj_Entry *last_interposer, *obj, *preload_tail; 500 const Elf_Phdr *phdr; 501 Objlist initlist; 502 RtldLockState lockstate; 503 struct stat st; 504 Elf_Addr *argcp; 505 char **argv, **env, **envp, *kexecpath; 506 const char *argv0, *binpath, *library_path_rpath, *static_tls_extra; 507 struct ld_env_var_desc *lvd; 508 caddr_t imgentry; 509 char buf[MAXPATHLEN]; 510 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 511 size_t sz; 512 #ifdef __powerpc__ 513 int old_auxv_format = 1; 514 #endif 515 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 516 517 /* 518 * On entry, the dynamic linker itself has not been relocated yet. 519 * Be very careful not to reference any global data until after 520 * init_rtld has returned. It is OK to reference file-scope statics 521 * and string constants, and to call static and global functions. 522 */ 523 524 /* Find the auxiliary vector on the stack. */ 525 argcp = sp; 526 argc = *sp++; 527 argv = (char **) sp; 528 sp += argc + 1; /* Skip over arguments and NULL terminator */ 529 env = (char **) sp; 530 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 531 ; 532 aux = (Elf_Auxinfo *) sp; 533 534 /* Digest the auxiliary vector. */ 535 for (i = 0; i < AT_COUNT; i++) 536 aux_info[i] = NULL; 537 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 538 if (auxp->a_type < AT_COUNT) 539 aux_info[auxp->a_type] = auxp; 540 #ifdef __powerpc__ 541 if (auxp->a_type == 23) /* AT_STACKPROT */ 542 old_auxv_format = 0; 543 #endif 544 } 545 546 #ifdef __powerpc__ 547 if (old_auxv_format) { 548 /* Remap from old-style auxv numbers. */ 549 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 550 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 551 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 552 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 553 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 554 aux_info[13] = NULL; /* AT_GID */ 555 556 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 557 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 558 aux_info[16] = aux_info[14]; /* AT_CANARY */ 559 aux_info[14] = NULL; /* AT_EGID */ 560 } 561 #endif 562 563 /* Initialize and relocate ourselves. */ 564 assert(aux_info[AT_BASE] != NULL); 565 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 566 567 dlerror_dflt_init(); 568 569 __progname = obj_rtld.path; 570 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 571 environ = env; 572 main_argc = argc; 573 main_argv = argv; 574 575 if (aux_info[AT_BSDFLAGS] != NULL && 576 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 577 ld_fast_sigblock = true; 578 579 trust = !issetugid(); 580 direct_exec = false; 581 582 md_abi_variant_hook(aux_info); 583 rtld_init_env_vars(env); 584 585 fd = -1; 586 if (aux_info[AT_EXECFD] != NULL) { 587 fd = aux_info[AT_EXECFD]->a_un.a_val; 588 } else { 589 assert(aux_info[AT_PHDR] != NULL); 590 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 591 if (phdr == obj_rtld.phdr) { 592 if (!trust) { 593 _rtld_error("Tainted process refusing to run binary %s", 594 argv0); 595 rtld_die(); 596 } 597 direct_exec = true; 598 599 dbg("opening main program in direct exec mode"); 600 if (argc >= 2) { 601 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 602 &argv0, &dir_ignore); 603 explicit_fd = (fd != -1); 604 binpath = NULL; 605 if (!explicit_fd) 606 fd = open_binary_fd(argv0, search_in_path, &binpath); 607 if (fstat(fd, &st) == -1) { 608 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 609 explicit_fd ? "user-provided descriptor" : argv0, 610 rtld_strerror(errno)); 611 rtld_die(); 612 } 613 614 /* 615 * Rough emulation of the permission checks done by 616 * execve(2), only Unix DACs are checked, ACLs are 617 * ignored. Preserve the semantic of disabling owner 618 * to execute if owner x bit is cleared, even if 619 * others x bit is enabled. 620 * mmap(2) does not allow to mmap with PROT_EXEC if 621 * binary' file comes from noexec mount. We cannot 622 * set a text reference on the binary. 623 */ 624 dir_enable = false; 625 if (st.st_uid == geteuid()) { 626 if ((st.st_mode & S_IXUSR) != 0) 627 dir_enable = true; 628 } else if (st.st_gid == getegid()) { 629 if ((st.st_mode & S_IXGRP) != 0) 630 dir_enable = true; 631 } else if ((st.st_mode & S_IXOTH) != 0) { 632 dir_enable = true; 633 } 634 if (!dir_enable && !dir_ignore) { 635 _rtld_error("No execute permission for binary %s", 636 argv0); 637 rtld_die(); 638 } 639 640 /* 641 * For direct exec mode, argv[0] is the interpreter 642 * name, we must remove it and shift arguments left 643 * before invoking binary main. Since stack layout 644 * places environment pointers and aux vectors right 645 * after the terminating NULL, we must shift 646 * environment and aux as well. 647 */ 648 main_argc = argc - rtld_argc; 649 for (i = 0; i <= main_argc; i++) 650 argv[i] = argv[i + rtld_argc]; 651 *argcp -= rtld_argc; 652 environ = env = envp = argv + main_argc + 1; 653 dbg("move env from %p to %p", envp + rtld_argc, envp); 654 do { 655 *envp = *(envp + rtld_argc); 656 } while (*envp++ != NULL); 657 aux = auxp = (Elf_Auxinfo *)envp; 658 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 659 dbg("move aux from %p to %p", auxpf, aux); 660 /* XXXKIB insert place for AT_EXECPATH if not present */ 661 for (;; auxp++, auxpf++) { 662 *auxp = *auxpf; 663 if (auxp->a_type == AT_NULL) 664 break; 665 } 666 /* Since the auxiliary vector has moved, redigest it. */ 667 for (i = 0; i < AT_COUNT; i++) 668 aux_info[i] = NULL; 669 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 670 if (auxp->a_type < AT_COUNT) 671 aux_info[auxp->a_type] = auxp; 672 } 673 674 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 675 if (binpath == NULL) { 676 aux_info[AT_EXECPATH] = NULL; 677 } else { 678 if (aux_info[AT_EXECPATH] == NULL) { 679 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 680 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 681 } 682 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 683 binpath); 684 } 685 } else { 686 _rtld_error("No binary"); 687 rtld_die(); 688 } 689 } 690 } 691 692 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 693 694 /* 695 * If the process is tainted, then we un-set the dangerous environment 696 * variables. The process will be marked as tainted until setuid(2) 697 * is called. If any child process calls setuid(2) we do not want any 698 * future processes to honor the potentially un-safe variables. 699 */ 700 if (!trust) { 701 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 702 lvd = &ld_env_vars[i]; 703 if (lvd->unsecure) 704 lvd->val = NULL; 705 } 706 } 707 708 ld_debug = ld_get_env_var(LD_DEBUG); 709 if (ld_bind_now == NULL) 710 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 711 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 712 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 713 libmap_override = ld_get_env_var(LD_LIBMAP); 714 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 715 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 716 ld_preload = ld_get_env_var(LD_PRELOAD); 717 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 718 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 719 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 720 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 721 if (library_path_rpath != NULL) { 722 if (library_path_rpath[0] == 'y' || 723 library_path_rpath[0] == 'Y' || 724 library_path_rpath[0] == '1') 725 ld_library_path_rpath = true; 726 else 727 ld_library_path_rpath = false; 728 } 729 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); 730 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { 731 sz = parse_integer(static_tls_extra); 732 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) 733 ld_static_tls_extra = sz; 734 } 735 dangerous_ld_env = libmap_disable || libmap_override != NULL || 736 ld_library_path != NULL || ld_preload != NULL || 737 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || 738 static_tls_extra != NULL; 739 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 740 ld_utrace = ld_get_env_var(LD_UTRACE); 741 742 set_ld_elf_hints_path(); 743 if (ld_debug != NULL && *ld_debug != '\0') 744 debug = 1; 745 dbg("%s is initialized, base address = %p", __progname, 746 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 747 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 748 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 749 750 dbg("initializing thread locks"); 751 lockdflt_init(); 752 753 /* 754 * Load the main program, or process its program header if it is 755 * already loaded. 756 */ 757 if (fd != -1) { /* Load the main program. */ 758 dbg("loading main program"); 759 obj_main = map_object(fd, argv0, NULL); 760 close(fd); 761 if (obj_main == NULL) 762 rtld_die(); 763 max_stack_flags = obj_main->stack_flags; 764 } else { /* Main program already loaded. */ 765 dbg("processing main program's program header"); 766 assert(aux_info[AT_PHDR] != NULL); 767 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 768 assert(aux_info[AT_PHNUM] != NULL); 769 phnum = aux_info[AT_PHNUM]->a_un.a_val; 770 assert(aux_info[AT_PHENT] != NULL); 771 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 772 assert(aux_info[AT_ENTRY] != NULL); 773 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 774 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 775 rtld_die(); 776 } 777 778 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 779 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 780 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 781 if (kexecpath[0] == '/') 782 obj_main->path = kexecpath; 783 else if (getcwd(buf, sizeof(buf)) == NULL || 784 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 785 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 786 obj_main->path = xstrdup(argv0); 787 else 788 obj_main->path = xstrdup(buf); 789 } else { 790 dbg("No AT_EXECPATH or direct exec"); 791 obj_main->path = xstrdup(argv0); 792 } 793 dbg("obj_main path %s", obj_main->path); 794 obj_main->mainprog = true; 795 796 if (aux_info[AT_STACKPROT] != NULL && 797 aux_info[AT_STACKPROT]->a_un.a_val != 0) 798 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 799 800 #ifndef COMPAT_libcompat 801 /* 802 * Get the actual dynamic linker pathname from the executable if 803 * possible. (It should always be possible.) That ensures that 804 * gdb will find the right dynamic linker even if a non-standard 805 * one is being used. 806 */ 807 if (obj_main->interp != NULL && 808 strcmp(obj_main->interp, obj_rtld.path) != 0) { 809 free(obj_rtld.path); 810 obj_rtld.path = xstrdup(obj_main->interp); 811 __progname = obj_rtld.path; 812 } 813 #endif 814 815 if (!digest_dynamic(obj_main, 0)) 816 rtld_die(); 817 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 818 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 819 obj_main->dynsymcount); 820 821 linkmap_add(obj_main); 822 linkmap_add(&obj_rtld); 823 824 /* Link the main program into the list of objects. */ 825 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 826 obj_count++; 827 obj_loads++; 828 829 /* Initialize a fake symbol for resolving undefined weak references. */ 830 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 831 sym_zero.st_shndx = SHN_UNDEF; 832 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 833 834 if (!libmap_disable) 835 libmap_disable = (bool)lm_init(libmap_override); 836 837 if (aux_info[AT_KPRELOAD] != NULL && 838 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 839 dbg("loading kernel vdso"); 840 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 841 rtld_die(); 842 } 843 844 dbg("loading LD_PRELOAD_FDS libraries"); 845 if (load_preload_objects(ld_preload_fds, true) == -1) 846 rtld_die(); 847 848 dbg("loading LD_PRELOAD libraries"); 849 if (load_preload_objects(ld_preload, false) == -1) 850 rtld_die(); 851 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 852 853 dbg("loading needed objects"); 854 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 855 0) == -1) 856 rtld_die(); 857 858 /* Make a list of all objects loaded at startup. */ 859 last_interposer = obj_main; 860 TAILQ_FOREACH(obj, &obj_list, next) { 861 if (obj->marker) 862 continue; 863 if (obj->z_interpose && obj != obj_main) { 864 objlist_put_after(&list_main, last_interposer, obj); 865 last_interposer = obj; 866 } else { 867 objlist_push_tail(&list_main, obj); 868 } 869 obj->refcount++; 870 } 871 872 dbg("checking for required versions"); 873 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 874 rtld_die(); 875 876 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 877 dump_auxv(aux_info); 878 879 if (ld_tracing) { /* We're done */ 880 trace_loaded_objects(obj_main, true); 881 exit(0); 882 } 883 884 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 885 dump_relocations(obj_main); 886 exit (0); 887 } 888 889 /* 890 * Processing tls relocations requires having the tls offsets 891 * initialized. Prepare offsets before starting initial 892 * relocation processing. 893 */ 894 dbg("initializing initial thread local storage offsets"); 895 STAILQ_FOREACH(entry, &list_main, link) { 896 /* 897 * Allocate all the initial objects out of the static TLS 898 * block even if they didn't ask for it. 899 */ 900 allocate_tls_offset(entry->obj); 901 } 902 903 if (relocate_objects(obj_main, 904 ld_bind_now != NULL && *ld_bind_now != '\0', 905 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 906 rtld_die(); 907 908 dbg("doing copy relocations"); 909 if (do_copy_relocations(obj_main) == -1) 910 rtld_die(); 911 912 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 913 dump_relocations(obj_main); 914 exit (0); 915 } 916 917 ifunc_init(aux_info); 918 919 /* 920 * Setup TLS for main thread. This must be done after the 921 * relocations are processed, since tls initialization section 922 * might be the subject for relocations. 923 */ 924 dbg("initializing initial thread local storage"); 925 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 926 927 dbg("initializing key program variables"); 928 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 929 set_program_var("environ", env); 930 set_program_var("__elf_aux_vector", aux); 931 932 /* Make a list of init functions to call. */ 933 objlist_init(&initlist); 934 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 935 preload_tail, &initlist); 936 937 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 938 939 map_stacks_exec(NULL); 940 941 if (!obj_main->crt_no_init) { 942 /* 943 * Make sure we don't call the main program's init and fini 944 * functions for binaries linked with old crt1 which calls 945 * _init itself. 946 */ 947 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 948 obj_main->preinit_array = obj_main->init_array = 949 obj_main->fini_array = (Elf_Addr)NULL; 950 } 951 952 if (direct_exec) { 953 /* Set osrel for direct-execed binary */ 954 mib[0] = CTL_KERN; 955 mib[1] = KERN_PROC; 956 mib[2] = KERN_PROC_OSREL; 957 mib[3] = getpid(); 958 osrel = obj_main->osrel; 959 sz = sizeof(old_osrel); 960 dbg("setting osrel to %d", osrel); 961 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 962 } 963 964 wlock_acquire(rtld_bind_lock, &lockstate); 965 966 dbg("resolving ifuncs"); 967 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 968 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 969 rtld_die(); 970 971 rtld_exit_ptr = rtld_exit; 972 if (obj_main->crt_no_init) 973 preinit_main(); 974 objlist_call_init(&initlist, &lockstate); 975 _r_debug_postinit(&obj_main->linkmap); 976 objlist_clear(&initlist); 977 dbg("loading filtees"); 978 TAILQ_FOREACH(obj, &obj_list, next) { 979 if (obj->marker) 980 continue; 981 if (ld_loadfltr || obj->z_loadfltr) 982 load_filtees(obj, 0, &lockstate); 983 } 984 985 dbg("enforcing main obj relro"); 986 if (obj_enforce_relro(obj_main) == -1) 987 rtld_die(); 988 989 lock_release(rtld_bind_lock, &lockstate); 990 991 dbg("transferring control to program entry point = %p", obj_main->entry); 992 993 /* Return the exit procedure and the program entry point. */ 994 *exit_proc = rtld_exit_ptr; 995 *objp = obj_main; 996 return ((func_ptr_type)obj_main->entry); 997 } 998 999 void * 1000 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 1001 { 1002 void *ptr; 1003 Elf_Addr target; 1004 1005 ptr = (void *)make_function_pointer(def, obj); 1006 target = call_ifunc_resolver(ptr); 1007 return ((void *)target); 1008 } 1009 1010 Elf_Addr 1011 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1012 { 1013 const Elf_Rel *rel; 1014 const Elf_Sym *def; 1015 const Obj_Entry *defobj; 1016 Elf_Addr *where; 1017 Elf_Addr target; 1018 RtldLockState lockstate; 1019 1020 rlock_acquire(rtld_bind_lock, &lockstate); 1021 if (sigsetjmp(lockstate.env, 0) != 0) 1022 lock_upgrade(rtld_bind_lock, &lockstate); 1023 if (obj->pltrel) 1024 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1025 else 1026 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1027 1028 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1029 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1030 NULL, &lockstate); 1031 if (def == NULL) 1032 rtld_die(); 1033 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1034 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1035 else 1036 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1037 1038 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1039 defobj->strtab + def->st_name, 1040 obj->path == NULL ? NULL : basename(obj->path), 1041 (void *)target, 1042 defobj->path == NULL ? NULL : basename(defobj->path)); 1043 1044 /* 1045 * Write the new contents for the jmpslot. Note that depending on 1046 * architecture, the value which we need to return back to the 1047 * lazy binding trampoline may or may not be the target 1048 * address. The value returned from reloc_jmpslot() is the value 1049 * that the trampoline needs. 1050 */ 1051 target = reloc_jmpslot(where, target, defobj, obj, rel); 1052 lock_release(rtld_bind_lock, &lockstate); 1053 return (target); 1054 } 1055 1056 /* 1057 * Error reporting function. Use it like printf. If formats the message 1058 * into a buffer, and sets things up so that the next call to dlerror() 1059 * will return the message. 1060 */ 1061 void 1062 _rtld_error(const char *fmt, ...) 1063 { 1064 va_list ap; 1065 1066 va_start(ap, fmt); 1067 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1068 fmt, ap); 1069 va_end(ap); 1070 *lockinfo.dlerror_seen() = 0; 1071 dbg("rtld_error: %s", lockinfo.dlerror_loc()); 1072 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1073 } 1074 1075 /* 1076 * Return a dynamically-allocated copy of the current error message, if any. 1077 */ 1078 static struct dlerror_save * 1079 errmsg_save(void) 1080 { 1081 struct dlerror_save *res; 1082 1083 res = xmalloc(sizeof(*res)); 1084 res->seen = *lockinfo.dlerror_seen(); 1085 if (res->seen == 0) 1086 res->msg = xstrdup(lockinfo.dlerror_loc()); 1087 return (res); 1088 } 1089 1090 /* 1091 * Restore the current error message from a copy which was previously saved 1092 * by errmsg_save(). The copy is freed. 1093 */ 1094 static void 1095 errmsg_restore(struct dlerror_save *saved_msg) 1096 { 1097 if (saved_msg == NULL || saved_msg->seen == 1) { 1098 *lockinfo.dlerror_seen() = 1; 1099 } else { 1100 *lockinfo.dlerror_seen() = 0; 1101 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1102 lockinfo.dlerror_loc_sz); 1103 free(saved_msg->msg); 1104 } 1105 free(saved_msg); 1106 } 1107 1108 static const char * 1109 basename(const char *name) 1110 { 1111 const char *p; 1112 1113 p = strrchr(name, '/'); 1114 return (p != NULL ? p + 1 : name); 1115 } 1116 1117 static struct utsname uts; 1118 1119 static char * 1120 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1121 const char *subst, bool may_free) 1122 { 1123 char *p, *p1, *res, *resp; 1124 int subst_len, kw_len, subst_count, old_len, new_len; 1125 1126 kw_len = strlen(kw); 1127 1128 /* 1129 * First, count the number of the keyword occurrences, to 1130 * preallocate the final string. 1131 */ 1132 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1133 p1 = strstr(p, kw); 1134 if (p1 == NULL) 1135 break; 1136 } 1137 1138 /* 1139 * If the keyword is not found, just return. 1140 * 1141 * Return non-substituted string if resolution failed. We 1142 * cannot do anything more reasonable, the failure mode of the 1143 * caller is unresolved library anyway. 1144 */ 1145 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1146 return (may_free ? real : xstrdup(real)); 1147 if (obj != NULL) 1148 subst = obj->origin_path; 1149 1150 /* 1151 * There is indeed something to substitute. Calculate the 1152 * length of the resulting string, and allocate it. 1153 */ 1154 subst_len = strlen(subst); 1155 old_len = strlen(real); 1156 new_len = old_len + (subst_len - kw_len) * subst_count; 1157 res = xmalloc(new_len + 1); 1158 1159 /* 1160 * Now, execute the substitution loop. 1161 */ 1162 for (p = real, resp = res, *resp = '\0';;) { 1163 p1 = strstr(p, kw); 1164 if (p1 != NULL) { 1165 /* Copy the prefix before keyword. */ 1166 memcpy(resp, p, p1 - p); 1167 resp += p1 - p; 1168 /* Keyword replacement. */ 1169 memcpy(resp, subst, subst_len); 1170 resp += subst_len; 1171 *resp = '\0'; 1172 p = p1 + kw_len; 1173 } else 1174 break; 1175 } 1176 1177 /* Copy to the end of string and finish. */ 1178 strcat(resp, p); 1179 if (may_free) 1180 free(real); 1181 return (res); 1182 } 1183 1184 static const struct { 1185 const char *kw; 1186 bool pass_obj; 1187 const char *subst; 1188 } tokens[] = { 1189 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1190 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1191 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1192 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1193 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1194 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1195 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1196 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1197 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, 1198 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, 1199 }; 1200 1201 static char * 1202 origin_subst(Obj_Entry *obj, const char *real) 1203 { 1204 char *res; 1205 int i; 1206 1207 if (obj == NULL || !trust) 1208 return (xstrdup(real)); 1209 if (uts.sysname[0] == '\0') { 1210 if (uname(&uts) != 0) { 1211 _rtld_error("utsname failed: %d", errno); 1212 return (NULL); 1213 } 1214 } 1215 1216 /* __DECONST is safe here since without may_free real is unchanged */ 1217 res = __DECONST(char *, real); 1218 for (i = 0; i < (int)nitems(tokens); i++) { 1219 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1220 res, tokens[i].kw, tokens[i].subst, i != 0); 1221 } 1222 return (res); 1223 } 1224 1225 void 1226 rtld_die(void) 1227 { 1228 const char *msg = dlerror(); 1229 1230 if (msg == NULL) 1231 msg = "Fatal error"; 1232 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1233 rtld_fdputstr(STDERR_FILENO, msg); 1234 rtld_fdputchar(STDERR_FILENO, '\n'); 1235 _exit(1); 1236 } 1237 1238 /* 1239 * Process a shared object's DYNAMIC section, and save the important 1240 * information in its Obj_Entry structure. 1241 */ 1242 static void 1243 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1244 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1245 { 1246 const Elf_Dyn *dynp; 1247 Needed_Entry **needed_tail = &obj->needed; 1248 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1249 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1250 const Elf_Hashelt *hashtab; 1251 const Elf32_Word *hashval; 1252 Elf32_Word bkt, nmaskwords; 1253 int bloom_size32; 1254 int plttype = DT_REL; 1255 1256 *dyn_rpath = NULL; 1257 *dyn_soname = NULL; 1258 *dyn_runpath = NULL; 1259 1260 obj->bind_now = false; 1261 dynp = obj->dynamic; 1262 if (dynp == NULL) 1263 return; 1264 for (; dynp->d_tag != DT_NULL; dynp++) { 1265 switch (dynp->d_tag) { 1266 1267 case DT_REL: 1268 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1269 break; 1270 1271 case DT_RELSZ: 1272 obj->relsize = dynp->d_un.d_val; 1273 break; 1274 1275 case DT_RELENT: 1276 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1277 break; 1278 1279 case DT_JMPREL: 1280 obj->pltrel = (const Elf_Rel *) 1281 (obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_PLTRELSZ: 1285 obj->pltrelsize = dynp->d_un.d_val; 1286 break; 1287 1288 case DT_RELA: 1289 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1290 break; 1291 1292 case DT_RELASZ: 1293 obj->relasize = dynp->d_un.d_val; 1294 break; 1295 1296 case DT_RELAENT: 1297 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1298 break; 1299 1300 case DT_RELR: 1301 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1302 break; 1303 1304 case DT_RELRSZ: 1305 obj->relrsize = dynp->d_un.d_val; 1306 break; 1307 1308 case DT_RELRENT: 1309 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1310 break; 1311 1312 case DT_PLTREL: 1313 plttype = dynp->d_un.d_val; 1314 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1315 break; 1316 1317 case DT_SYMTAB: 1318 obj->symtab = (const Elf_Sym *) 1319 (obj->relocbase + dynp->d_un.d_ptr); 1320 break; 1321 1322 case DT_SYMENT: 1323 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1324 break; 1325 1326 case DT_STRTAB: 1327 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1328 break; 1329 1330 case DT_STRSZ: 1331 obj->strsize = dynp->d_un.d_val; 1332 break; 1333 1334 case DT_VERNEED: 1335 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1336 dynp->d_un.d_val); 1337 break; 1338 1339 case DT_VERNEEDNUM: 1340 obj->verneednum = dynp->d_un.d_val; 1341 break; 1342 1343 case DT_VERDEF: 1344 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1345 dynp->d_un.d_val); 1346 break; 1347 1348 case DT_VERDEFNUM: 1349 obj->verdefnum = dynp->d_un.d_val; 1350 break; 1351 1352 case DT_VERSYM: 1353 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1354 dynp->d_un.d_val); 1355 break; 1356 1357 case DT_HASH: 1358 { 1359 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1360 dynp->d_un.d_ptr); 1361 obj->nbuckets = hashtab[0]; 1362 obj->nchains = hashtab[1]; 1363 obj->buckets = hashtab + 2; 1364 obj->chains = obj->buckets + obj->nbuckets; 1365 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1366 obj->buckets != NULL; 1367 } 1368 break; 1369 1370 case DT_GNU_HASH: 1371 { 1372 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1373 dynp->d_un.d_ptr); 1374 obj->nbuckets_gnu = hashtab[0]; 1375 obj->symndx_gnu = hashtab[1]; 1376 nmaskwords = hashtab[2]; 1377 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1378 obj->maskwords_bm_gnu = nmaskwords - 1; 1379 obj->shift2_gnu = hashtab[3]; 1380 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1381 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1382 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1383 obj->symndx_gnu; 1384 /* Number of bitmask words is required to be power of 2 */ 1385 obj->valid_hash_gnu = powerof2(nmaskwords) && 1386 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1387 } 1388 break; 1389 1390 case DT_NEEDED: 1391 if (!obj->rtld) { 1392 Needed_Entry *nep = NEW(Needed_Entry); 1393 nep->name = dynp->d_un.d_val; 1394 nep->obj = NULL; 1395 nep->next = NULL; 1396 1397 *needed_tail = nep; 1398 needed_tail = &nep->next; 1399 } 1400 break; 1401 1402 case DT_FILTER: 1403 if (!obj->rtld) { 1404 Needed_Entry *nep = NEW(Needed_Entry); 1405 nep->name = dynp->d_un.d_val; 1406 nep->obj = NULL; 1407 nep->next = NULL; 1408 1409 *needed_filtees_tail = nep; 1410 needed_filtees_tail = &nep->next; 1411 1412 if (obj->linkmap.l_refname == NULL) 1413 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1414 } 1415 break; 1416 1417 case DT_AUXILIARY: 1418 if (!obj->rtld) { 1419 Needed_Entry *nep = NEW(Needed_Entry); 1420 nep->name = dynp->d_un.d_val; 1421 nep->obj = NULL; 1422 nep->next = NULL; 1423 1424 *needed_aux_filtees_tail = nep; 1425 needed_aux_filtees_tail = &nep->next; 1426 } 1427 break; 1428 1429 case DT_PLTGOT: 1430 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1431 break; 1432 1433 case DT_TEXTREL: 1434 obj->textrel = true; 1435 break; 1436 1437 case DT_SYMBOLIC: 1438 obj->symbolic = true; 1439 break; 1440 1441 case DT_RPATH: 1442 /* 1443 * We have to wait until later to process this, because we 1444 * might not have gotten the address of the string table yet. 1445 */ 1446 *dyn_rpath = dynp; 1447 break; 1448 1449 case DT_SONAME: 1450 *dyn_soname = dynp; 1451 break; 1452 1453 case DT_RUNPATH: 1454 *dyn_runpath = dynp; 1455 break; 1456 1457 case DT_INIT: 1458 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1459 break; 1460 1461 case DT_PREINIT_ARRAY: 1462 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1463 break; 1464 1465 case DT_PREINIT_ARRAYSZ: 1466 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1467 break; 1468 1469 case DT_INIT_ARRAY: 1470 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1471 break; 1472 1473 case DT_INIT_ARRAYSZ: 1474 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1475 break; 1476 1477 case DT_FINI: 1478 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1479 break; 1480 1481 case DT_FINI_ARRAY: 1482 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1483 break; 1484 1485 case DT_FINI_ARRAYSZ: 1486 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1487 break; 1488 1489 case DT_DEBUG: 1490 if (!early) 1491 dbg("Filling in DT_DEBUG entry"); 1492 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1493 break; 1494 1495 case DT_FLAGS: 1496 if (dynp->d_un.d_val & DF_ORIGIN) 1497 obj->z_origin = true; 1498 if (dynp->d_un.d_val & DF_SYMBOLIC) 1499 obj->symbolic = true; 1500 if (dynp->d_un.d_val & DF_TEXTREL) 1501 obj->textrel = true; 1502 if (dynp->d_un.d_val & DF_BIND_NOW) 1503 obj->bind_now = true; 1504 if (dynp->d_un.d_val & DF_STATIC_TLS) 1505 obj->static_tls = true; 1506 break; 1507 1508 case DT_FLAGS_1: 1509 if (dynp->d_un.d_val & DF_1_NOOPEN) 1510 obj->z_noopen = true; 1511 if (dynp->d_un.d_val & DF_1_ORIGIN) 1512 obj->z_origin = true; 1513 if (dynp->d_un.d_val & DF_1_GLOBAL) 1514 obj->z_global = true; 1515 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1516 obj->bind_now = true; 1517 if (dynp->d_un.d_val & DF_1_NODELETE) 1518 obj->z_nodelete = true; 1519 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1520 obj->z_loadfltr = true; 1521 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1522 obj->z_interpose = true; 1523 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1524 obj->z_nodeflib = true; 1525 if (dynp->d_un.d_val & DF_1_PIE) 1526 obj->z_pie = true; 1527 break; 1528 1529 default: 1530 if (arch_digest_dynamic(obj, dynp)) 1531 break; 1532 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_NOTE: 1676 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1677 note_end = note_start + ph->p_filesz; 1678 digest_notes(obj, note_start, note_end); 1679 break; 1680 } 1681 } 1682 if (nsegs < 1) { 1683 _rtld_error("%s: too few PT_LOAD segments", path); 1684 return (NULL); 1685 } 1686 1687 obj->entry = entry; 1688 return (obj); 1689 } 1690 1691 void 1692 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1693 { 1694 const Elf_Note *note; 1695 const char *note_name; 1696 uintptr_t p; 1697 1698 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1699 note = (const Elf_Note *)((const char *)(note + 1) + 1700 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1701 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1702 if (arch_digest_note(obj, note)) 1703 continue; 1704 1705 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1706 note->n_descsz != sizeof(int32_t)) 1707 continue; 1708 if (note->n_type != NT_FREEBSD_ABI_TAG && 1709 note->n_type != NT_FREEBSD_FEATURE_CTL && 1710 note->n_type != NT_FREEBSD_NOINIT_TAG) 1711 continue; 1712 note_name = (const char *)(note + 1); 1713 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1714 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1715 continue; 1716 switch (note->n_type) { 1717 case NT_FREEBSD_ABI_TAG: 1718 /* FreeBSD osrel note */ 1719 p = (uintptr_t)(note + 1); 1720 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1721 obj->osrel = *(const int32_t *)(p); 1722 dbg("note osrel %d", obj->osrel); 1723 break; 1724 case NT_FREEBSD_FEATURE_CTL: 1725 /* FreeBSD ABI feature control note */ 1726 p = (uintptr_t)(note + 1); 1727 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1728 obj->fctl0 = *(const uint32_t *)(p); 1729 dbg("note fctl0 %#x", obj->fctl0); 1730 break; 1731 case NT_FREEBSD_NOINIT_TAG: 1732 /* FreeBSD 'crt does not call init' note */ 1733 obj->crt_no_init = true; 1734 dbg("note crt_no_init"); 1735 break; 1736 } 1737 } 1738 } 1739 1740 static Obj_Entry * 1741 dlcheck(void *handle) 1742 { 1743 Obj_Entry *obj; 1744 1745 TAILQ_FOREACH(obj, &obj_list, next) { 1746 if (obj == (Obj_Entry *) handle) 1747 break; 1748 } 1749 1750 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1751 _rtld_error("Invalid shared object handle %p", handle); 1752 return (NULL); 1753 } 1754 return (obj); 1755 } 1756 1757 /* 1758 * If the given object is already in the donelist, return true. Otherwise 1759 * add the object to the list and return false. 1760 */ 1761 static bool 1762 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1763 { 1764 unsigned int i; 1765 1766 for (i = 0; i < dlp->num_used; i++) 1767 if (dlp->objs[i] == obj) 1768 return (true); 1769 /* 1770 * Our donelist allocation should always be sufficient. But if 1771 * our threads locking isn't working properly, more shared objects 1772 * could have been loaded since we allocated the list. That should 1773 * never happen, but we'll handle it properly just in case it does. 1774 */ 1775 if (dlp->num_used < dlp->num_alloc) 1776 dlp->objs[dlp->num_used++] = obj; 1777 return (false); 1778 } 1779 1780 /* 1781 * SysV hash function for symbol table lookup. It is a slightly optimized 1782 * version of the hash specified by the System V ABI. 1783 */ 1784 Elf32_Word 1785 elf_hash(const char *name) 1786 { 1787 const unsigned char *p = (const unsigned char *)name; 1788 Elf32_Word h = 0; 1789 1790 while (*p != '\0') { 1791 h = (h << 4) + *p++; 1792 h ^= (h >> 24) & 0xf0; 1793 } 1794 return (h & 0x0fffffff); 1795 } 1796 1797 /* 1798 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1799 * unsigned in case it's implemented with a wider type. 1800 */ 1801 static uint32_t 1802 gnu_hash(const char *s) 1803 { 1804 uint32_t h; 1805 unsigned char c; 1806 1807 h = 5381; 1808 for (c = *s; c != '\0'; c = *++s) 1809 h = h * 33 + c; 1810 return (h & 0xffffffff); 1811 } 1812 1813 1814 /* 1815 * Find the library with the given name, and return its full pathname. 1816 * The returned string is dynamically allocated. Generates an error 1817 * message and returns NULL if the library cannot be found. 1818 * 1819 * If the second argument is non-NULL, then it refers to an already- 1820 * loaded shared object, whose library search path will be searched. 1821 * 1822 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1823 * descriptor (which is close-on-exec) will be passed out via the third 1824 * argument. 1825 * 1826 * The search order is: 1827 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1828 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1829 * LD_LIBRARY_PATH 1830 * DT_RUNPATH in the referencing file 1831 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1832 * from list) 1833 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1834 * 1835 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1836 */ 1837 static char * 1838 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1839 { 1840 char *pathname, *refobj_path; 1841 const char *name; 1842 bool nodeflib, objgiven; 1843 1844 objgiven = refobj != NULL; 1845 1846 if (libmap_disable || !objgiven || 1847 (name = lm_find(refobj->path, xname)) == NULL) 1848 name = xname; 1849 1850 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1851 if (name[0] != '/' && !trust) { 1852 _rtld_error("Absolute pathname required " 1853 "for shared object \"%s\"", name); 1854 return (NULL); 1855 } 1856 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1857 __DECONST(char *, name))); 1858 } 1859 1860 dbg(" Searching for \"%s\"", name); 1861 refobj_path = objgiven ? refobj->path : NULL; 1862 1863 /* 1864 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1865 * back to pre-conforming behaviour if user requested so with 1866 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1867 * nodeflib. 1868 */ 1869 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1870 pathname = search_library_path(name, ld_library_path, 1871 refobj_path, fdp); 1872 if (pathname != NULL) 1873 return (pathname); 1874 if (refobj != NULL) { 1875 pathname = search_library_path(name, refobj->rpath, 1876 refobj_path, fdp); 1877 if (pathname != NULL) 1878 return (pathname); 1879 } 1880 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1881 if (pathname != NULL) 1882 return (pathname); 1883 pathname = search_library_path(name, gethints(false), 1884 refobj_path, fdp); 1885 if (pathname != NULL) 1886 return (pathname); 1887 pathname = search_library_path(name, ld_standard_library_path, 1888 refobj_path, fdp); 1889 if (pathname != NULL) 1890 return (pathname); 1891 } else { 1892 nodeflib = objgiven ? refobj->z_nodeflib : false; 1893 if (objgiven) { 1894 pathname = search_library_path(name, refobj->rpath, 1895 refobj->path, fdp); 1896 if (pathname != NULL) 1897 return (pathname); 1898 } 1899 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1900 pathname = search_library_path(name, obj_main->rpath, 1901 refobj_path, fdp); 1902 if (pathname != NULL) 1903 return (pathname); 1904 } 1905 pathname = search_library_path(name, ld_library_path, 1906 refobj_path, fdp); 1907 if (pathname != NULL) 1908 return (pathname); 1909 if (objgiven) { 1910 pathname = search_library_path(name, refobj->runpath, 1911 refobj_path, fdp); 1912 if (pathname != NULL) 1913 return (pathname); 1914 } 1915 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1916 if (pathname != NULL) 1917 return (pathname); 1918 pathname = search_library_path(name, gethints(nodeflib), 1919 refobj_path, fdp); 1920 if (pathname != NULL) 1921 return (pathname); 1922 if (objgiven && !nodeflib) { 1923 pathname = search_library_path(name, 1924 ld_standard_library_path, refobj_path, fdp); 1925 if (pathname != NULL) 1926 return (pathname); 1927 } 1928 } 1929 1930 if (objgiven && refobj->path != NULL) { 1931 _rtld_error("Shared object \"%s\" not found, " 1932 "required by \"%s\"", name, basename(refobj->path)); 1933 } else { 1934 _rtld_error("Shared object \"%s\" not found", name); 1935 } 1936 return (NULL); 1937 } 1938 1939 /* 1940 * Given a symbol number in a referencing object, find the corresponding 1941 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1942 * no definition was found. Returns a pointer to the Obj_Entry of the 1943 * defining object via the reference parameter DEFOBJ_OUT. 1944 */ 1945 const Elf_Sym * 1946 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1947 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1948 RtldLockState *lockstate) 1949 { 1950 const Elf_Sym *ref; 1951 const Elf_Sym *def; 1952 const Obj_Entry *defobj; 1953 const Ver_Entry *ve; 1954 SymLook req; 1955 const char *name; 1956 int res; 1957 1958 /* 1959 * If we have already found this symbol, get the information from 1960 * the cache. 1961 */ 1962 if (symnum >= refobj->dynsymcount) 1963 return (NULL); /* Bad object */ 1964 if (cache != NULL && cache[symnum].sym != NULL) { 1965 *defobj_out = cache[symnum].obj; 1966 return (cache[symnum].sym); 1967 } 1968 1969 ref = refobj->symtab + symnum; 1970 name = refobj->strtab + ref->st_name; 1971 def = NULL; 1972 defobj = NULL; 1973 ve = NULL; 1974 1975 /* 1976 * We don't have to do a full scale lookup if the symbol is local. 1977 * We know it will bind to the instance in this load module; to 1978 * which we already have a pointer (ie ref). By not doing a lookup, 1979 * we not only improve performance, but it also avoids unresolvable 1980 * symbols when local symbols are not in the hash table. This has 1981 * been seen with the ia64 toolchain. 1982 */ 1983 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1984 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1985 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1986 symnum); 1987 } 1988 symlook_init(&req, name); 1989 req.flags = flags; 1990 ve = req.ventry = fetch_ventry(refobj, symnum); 1991 req.lockstate = lockstate; 1992 res = symlook_default(&req, refobj); 1993 if (res == 0) { 1994 def = req.sym_out; 1995 defobj = req.defobj_out; 1996 } 1997 } else { 1998 def = ref; 1999 defobj = refobj; 2000 } 2001 2002 /* 2003 * If we found no definition and the reference is weak, treat the 2004 * symbol as having the value zero. 2005 */ 2006 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2007 def = &sym_zero; 2008 defobj = obj_main; 2009 } 2010 2011 if (def != NULL) { 2012 *defobj_out = defobj; 2013 /* Record the information in the cache to avoid subsequent lookups. */ 2014 if (cache != NULL) { 2015 cache[symnum].sym = def; 2016 cache[symnum].obj = defobj; 2017 } 2018 } else { 2019 if (refobj != &obj_rtld) 2020 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2021 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2022 } 2023 return (def); 2024 } 2025 2026 /* Convert between native byte order and forced little resp. big endian. */ 2027 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) 2028 2029 /* 2030 * Return the search path from the ldconfig hints file, reading it if 2031 * necessary. If nostdlib is true, then the default search paths are 2032 * not added to result. 2033 * 2034 * Returns NULL if there are problems with the hints file, 2035 * or if the search path there is empty. 2036 */ 2037 static const char * 2038 gethints(bool nostdlib) 2039 { 2040 static char *filtered_path; 2041 static const char *hints; 2042 static struct elfhints_hdr hdr; 2043 struct fill_search_info_args sargs, hargs; 2044 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2045 struct dl_serpath *SLPpath, *hintpath; 2046 char *p; 2047 struct stat hint_stat; 2048 unsigned int SLPndx, hintndx, fndx, fcount; 2049 int fd; 2050 size_t flen; 2051 uint32_t dl; 2052 uint32_t magic; /* Magic number */ 2053 uint32_t version; /* File version (1) */ 2054 uint32_t strtab; /* Offset of string table in file */ 2055 uint32_t dirlist; /* Offset of directory list in string table */ 2056 uint32_t dirlistlen; /* strlen(dirlist) */ 2057 bool is_le; /* Does the hints file use little endian */ 2058 bool skip; 2059 2060 /* First call, read the hints file */ 2061 if (hints == NULL) { 2062 /* Keep from trying again in case the hints file is bad. */ 2063 hints = ""; 2064 2065 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { 2066 dbg("failed to open hints file \"%s\"", ld_elf_hints_path); 2067 return (NULL); 2068 } 2069 2070 /* 2071 * Check of hdr.dirlistlen value against type limit 2072 * intends to pacify static analyzers. Further 2073 * paranoia leads to checks that dirlist is fully 2074 * contained in the file range. 2075 */ 2076 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { 2077 dbg("failed to read %lu bytes from hints file \"%s\"", 2078 (u_long)sizeof hdr, ld_elf_hints_path); 2079 cleanup1: 2080 close(fd); 2081 hdr.dirlistlen = 0; 2082 return (NULL); 2083 } 2084 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); 2085 dbg("hints file byte-order: %s-endian", 2086 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big"); 2087 is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC); 2088 magic = COND_SWAP(hdr.magic); 2089 version = COND_SWAP(hdr.version); 2090 strtab = COND_SWAP(hdr.strtab); 2091 dirlist = COND_SWAP(hdr.dirlist); 2092 dirlistlen = COND_SWAP(hdr.dirlistlen); 2093 if (magic != ELFHINTS_MAGIC) { 2094 dbg("invalid magic number %#08x (expected: %#08x)", 2095 magic, ELFHINTS_MAGIC); 2096 goto cleanup1; 2097 } 2098 if (version != 1) { 2099 dbg("hints file version %d (expected: 1)", version); 2100 goto cleanup1; 2101 } 2102 if (dirlistlen > UINT_MAX / 2) { 2103 dbg("directory list is to long: %d > %d", 2104 dirlistlen, UINT_MAX / 2); 2105 goto cleanup1; 2106 } 2107 if (fstat(fd, &hint_stat) == -1) { 2108 dbg("failed to find length of hints file \"%s\"", 2109 ld_elf_hints_path); 2110 goto cleanup1; 2111 } 2112 dl = strtab; 2113 if (dl + dirlist < dl) { 2114 dbg("invalid string table position %d", dl); 2115 goto cleanup1; 2116 } 2117 dl += dirlist; 2118 if (dl + dirlistlen < dl) { 2119 dbg("invalid directory list offset %d", dirlist); 2120 goto cleanup1; 2121 } 2122 dl += dirlistlen; 2123 if (dl > hint_stat.st_size) { 2124 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", 2125 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); 2126 goto cleanup1; 2127 } 2128 p = xmalloc(dirlistlen + 1); 2129 if (pread(fd, p, dirlistlen + 1, 2130 strtab + dirlist) != (ssize_t)dirlistlen + 1 || 2131 p[dirlistlen] != '\0') { 2132 free(p); 2133 dbg("failed to read %d bytes starting at %d from hints file \"%s\"", 2134 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); 2135 goto cleanup1; 2136 } 2137 hints = p; 2138 close(fd); 2139 } 2140 2141 /* 2142 * If caller agreed to receive list which includes the default 2143 * paths, we are done. Otherwise, if we still did not 2144 * calculated filtered result, do it now. 2145 */ 2146 if (!nostdlib) 2147 return (hints[0] != '\0' ? hints : NULL); 2148 if (filtered_path != NULL) 2149 goto filt_ret; 2150 2151 /* 2152 * Obtain the list of all configured search paths, and the 2153 * list of the default paths. 2154 * 2155 * First estimate the size of the results. 2156 */ 2157 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2158 smeta.dls_cnt = 0; 2159 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2160 hmeta.dls_cnt = 0; 2161 2162 sargs.request = RTLD_DI_SERINFOSIZE; 2163 sargs.serinfo = &smeta; 2164 hargs.request = RTLD_DI_SERINFOSIZE; 2165 hargs.serinfo = &hmeta; 2166 2167 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2168 &sargs); 2169 path_enumerate(hints, fill_search_info, NULL, &hargs); 2170 2171 SLPinfo = xmalloc(smeta.dls_size); 2172 hintinfo = xmalloc(hmeta.dls_size); 2173 2174 /* 2175 * Next fetch both sets of paths. 2176 */ 2177 sargs.request = RTLD_DI_SERINFO; 2178 sargs.serinfo = SLPinfo; 2179 sargs.serpath = &SLPinfo->dls_serpath[0]; 2180 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2181 2182 hargs.request = RTLD_DI_SERINFO; 2183 hargs.serinfo = hintinfo; 2184 hargs.serpath = &hintinfo->dls_serpath[0]; 2185 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2186 2187 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2188 &sargs); 2189 path_enumerate(hints, fill_search_info, NULL, &hargs); 2190 2191 /* 2192 * Now calculate the difference between two sets, by excluding 2193 * standard paths from the full set. 2194 */ 2195 fndx = 0; 2196 fcount = 0; 2197 filtered_path = xmalloc(dirlistlen + 1); 2198 hintpath = &hintinfo->dls_serpath[0]; 2199 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2200 skip = false; 2201 SLPpath = &SLPinfo->dls_serpath[0]; 2202 /* 2203 * Check each standard path against current. 2204 */ 2205 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2206 /* matched, skip the path */ 2207 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2208 skip = true; 2209 break; 2210 } 2211 } 2212 if (skip) 2213 continue; 2214 /* 2215 * Not matched against any standard path, add the path 2216 * to result. Separate consequtive paths with ':'. 2217 */ 2218 if (fcount > 0) { 2219 filtered_path[fndx] = ':'; 2220 fndx++; 2221 } 2222 fcount++; 2223 flen = strlen(hintpath->dls_name); 2224 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2225 fndx += flen; 2226 } 2227 filtered_path[fndx] = '\0'; 2228 2229 free(SLPinfo); 2230 free(hintinfo); 2231 2232 filt_ret: 2233 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2234 } 2235 2236 static void 2237 init_dag(Obj_Entry *root) 2238 { 2239 const Needed_Entry *needed; 2240 const Objlist_Entry *elm; 2241 DoneList donelist; 2242 2243 if (root->dag_inited) 2244 return; 2245 donelist_init(&donelist); 2246 2247 /* Root object belongs to own DAG. */ 2248 objlist_push_tail(&root->dldags, root); 2249 objlist_push_tail(&root->dagmembers, root); 2250 donelist_check(&donelist, root); 2251 2252 /* 2253 * Add dependencies of root object to DAG in breadth order 2254 * by exploiting the fact that each new object get added 2255 * to the tail of the dagmembers list. 2256 */ 2257 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2258 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2259 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2260 continue; 2261 objlist_push_tail(&needed->obj->dldags, root); 2262 objlist_push_tail(&root->dagmembers, needed->obj); 2263 } 2264 } 2265 root->dag_inited = true; 2266 } 2267 2268 static void 2269 init_marker(Obj_Entry *marker) 2270 { 2271 2272 bzero(marker, sizeof(*marker)); 2273 marker->marker = true; 2274 } 2275 2276 Obj_Entry * 2277 globallist_curr(const Obj_Entry *obj) 2278 { 2279 2280 for (;;) { 2281 if (obj == NULL) 2282 return (NULL); 2283 if (!obj->marker) 2284 return (__DECONST(Obj_Entry *, obj)); 2285 obj = TAILQ_PREV(obj, obj_entry_q, next); 2286 } 2287 } 2288 2289 Obj_Entry * 2290 globallist_next(const Obj_Entry *obj) 2291 { 2292 2293 for (;;) { 2294 obj = TAILQ_NEXT(obj, next); 2295 if (obj == NULL) 2296 return (NULL); 2297 if (!obj->marker) 2298 return (__DECONST(Obj_Entry *, obj)); 2299 } 2300 } 2301 2302 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2303 static void 2304 hold_object(Obj_Entry *obj) 2305 { 2306 2307 obj->holdcount++; 2308 } 2309 2310 static void 2311 unhold_object(Obj_Entry *obj) 2312 { 2313 2314 assert(obj->holdcount > 0); 2315 if (--obj->holdcount == 0 && obj->unholdfree) 2316 release_object(obj); 2317 } 2318 2319 static void 2320 process_z(Obj_Entry *root) 2321 { 2322 const Objlist_Entry *elm; 2323 Obj_Entry *obj; 2324 2325 /* 2326 * Walk over object DAG and process every dependent object 2327 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2328 * to grow their own DAG. 2329 * 2330 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2331 * symlook_global() to work. 2332 * 2333 * For DF_1_NODELETE, the DAG should have its reference upped. 2334 */ 2335 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2336 obj = elm->obj; 2337 if (obj == NULL) 2338 continue; 2339 if (obj->z_nodelete && !obj->ref_nodel) { 2340 dbg("obj %s -z nodelete", obj->path); 2341 init_dag(obj); 2342 ref_dag(obj); 2343 obj->ref_nodel = true; 2344 } 2345 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2346 dbg("obj %s -z global", obj->path); 2347 objlist_push_tail(&list_global, obj); 2348 init_dag(obj); 2349 } 2350 } 2351 } 2352 2353 static void 2354 parse_rtld_phdr(Obj_Entry *obj) 2355 { 2356 const Elf_Phdr *ph; 2357 Elf_Addr note_start, note_end; 2358 2359 obj->stack_flags = PF_X | PF_R | PF_W; 2360 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2361 obj->phsize; ph++) { 2362 switch (ph->p_type) { 2363 case PT_GNU_STACK: 2364 obj->stack_flags = ph->p_flags; 2365 break; 2366 case PT_NOTE: 2367 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2368 note_end = note_start + ph->p_filesz; 2369 digest_notes(obj, note_start, note_end); 2370 break; 2371 } 2372 } 2373 } 2374 2375 /* 2376 * Initialize the dynamic linker. The argument is the address at which 2377 * the dynamic linker has been mapped into memory. The primary task of 2378 * this function is to relocate the dynamic linker. 2379 */ 2380 static void 2381 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2382 { 2383 Obj_Entry objtmp; /* Temporary rtld object */ 2384 const Elf_Ehdr *ehdr; 2385 const Elf_Dyn *dyn_rpath; 2386 const Elf_Dyn *dyn_soname; 2387 const Elf_Dyn *dyn_runpath; 2388 2389 /* 2390 * Conjure up an Obj_Entry structure for the dynamic linker. 2391 * 2392 * The "path" member can't be initialized yet because string constants 2393 * cannot yet be accessed. Below we will set it correctly. 2394 */ 2395 memset(&objtmp, 0, sizeof(objtmp)); 2396 objtmp.path = NULL; 2397 objtmp.rtld = true; 2398 objtmp.mapbase = mapbase; 2399 #ifdef PIC 2400 objtmp.relocbase = mapbase; 2401 #endif 2402 2403 objtmp.dynamic = rtld_dynamic(&objtmp); 2404 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2405 assert(objtmp.needed == NULL); 2406 assert(!objtmp.textrel); 2407 /* 2408 * Temporarily put the dynamic linker entry into the object list, so 2409 * that symbols can be found. 2410 */ 2411 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2412 2413 ehdr = (Elf_Ehdr *)mapbase; 2414 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2415 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2416 2417 /* Initialize the object list. */ 2418 TAILQ_INIT(&obj_list); 2419 2420 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2421 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2422 2423 /* The page size is required by the dynamic memory allocator. */ 2424 init_pagesizes(aux_info); 2425 2426 if (aux_info[AT_OSRELDATE] != NULL) 2427 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2428 2429 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2430 2431 /* Replace the path with a dynamically allocated copy. */ 2432 obj_rtld.path = xstrdup(ld_path_rtld); 2433 2434 parse_rtld_phdr(&obj_rtld); 2435 if (obj_enforce_relro(&obj_rtld) == -1) 2436 rtld_die(); 2437 2438 r_debug.r_version = R_DEBUG_VERSION; 2439 r_debug.r_brk = r_debug_state; 2440 r_debug.r_state = RT_CONSISTENT; 2441 r_debug.r_ldbase = obj_rtld.relocbase; 2442 } 2443 2444 /* 2445 * Retrieve the array of supported page sizes. The kernel provides the page 2446 * sizes in increasing order. 2447 */ 2448 static void 2449 init_pagesizes(Elf_Auxinfo **aux_info) 2450 { 2451 static size_t psa[MAXPAGESIZES]; 2452 int mib[2]; 2453 size_t len, size; 2454 2455 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2456 NULL) { 2457 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2458 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2459 } else { 2460 len = 2; 2461 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2462 size = sizeof(psa); 2463 else { 2464 /* As a fallback, retrieve the base page size. */ 2465 size = sizeof(psa[0]); 2466 if (aux_info[AT_PAGESZ] != NULL) { 2467 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2468 goto psa_filled; 2469 } else { 2470 mib[0] = CTL_HW; 2471 mib[1] = HW_PAGESIZE; 2472 len = 2; 2473 } 2474 } 2475 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2476 _rtld_error("sysctl for hw.pagesize(s) failed"); 2477 rtld_die(); 2478 } 2479 psa_filled: 2480 pagesizes = psa; 2481 } 2482 npagesizes = size / sizeof(pagesizes[0]); 2483 /* Discard any invalid entries at the end of the array. */ 2484 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2485 npagesizes--; 2486 2487 page_size = pagesizes[0]; 2488 } 2489 2490 /* 2491 * Add the init functions from a needed object list (and its recursive 2492 * needed objects) to "list". This is not used directly; it is a helper 2493 * function for initlist_add_objects(). The write lock must be held 2494 * when this function is called. 2495 */ 2496 static void 2497 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2498 { 2499 /* Recursively process the successor needed objects. */ 2500 if (needed->next != NULL) 2501 initlist_add_neededs(needed->next, list); 2502 2503 /* Process the current needed object. */ 2504 if (needed->obj != NULL) 2505 initlist_add_objects(needed->obj, needed->obj, list); 2506 } 2507 2508 /* 2509 * Scan all of the DAGs rooted in the range of objects from "obj" to 2510 * "tail" and add their init functions to "list". This recurses over 2511 * the DAGs and ensure the proper init ordering such that each object's 2512 * needed libraries are initialized before the object itself. At the 2513 * same time, this function adds the objects to the global finalization 2514 * list "list_fini" in the opposite order. The write lock must be 2515 * held when this function is called. 2516 */ 2517 static void 2518 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2519 { 2520 Obj_Entry *nobj; 2521 2522 if (obj->init_scanned || obj->init_done) 2523 return; 2524 obj->init_scanned = true; 2525 2526 /* Recursively process the successor objects. */ 2527 nobj = globallist_next(obj); 2528 if (nobj != NULL && obj != tail) 2529 initlist_add_objects(nobj, tail, list); 2530 2531 /* Recursively process the needed objects. */ 2532 if (obj->needed != NULL) 2533 initlist_add_neededs(obj->needed, list); 2534 if (obj->needed_filtees != NULL) 2535 initlist_add_neededs(obj->needed_filtees, list); 2536 if (obj->needed_aux_filtees != NULL) 2537 initlist_add_neededs(obj->needed_aux_filtees, list); 2538 2539 /* Add the object to the init list. */ 2540 objlist_push_tail(list, obj); 2541 2542 /* Add the object to the global fini list in the reverse order. */ 2543 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2544 && !obj->on_fini_list) { 2545 objlist_push_head(&list_fini, obj); 2546 obj->on_fini_list = true; 2547 } 2548 } 2549 2550 static void 2551 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2552 { 2553 Needed_Entry *needed, *needed1; 2554 2555 for (needed = n; needed != NULL; needed = needed->next) { 2556 if (needed->obj != NULL) { 2557 dlclose_locked(needed->obj, lockstate); 2558 needed->obj = NULL; 2559 } 2560 } 2561 for (needed = n; needed != NULL; needed = needed1) { 2562 needed1 = needed->next; 2563 free(needed); 2564 } 2565 } 2566 2567 static void 2568 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2569 { 2570 2571 free_needed_filtees(obj->needed_filtees, lockstate); 2572 obj->needed_filtees = NULL; 2573 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2574 obj->needed_aux_filtees = NULL; 2575 obj->filtees_loaded = false; 2576 } 2577 2578 static void 2579 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2580 RtldLockState *lockstate) 2581 { 2582 2583 for (; needed != NULL; needed = needed->next) { 2584 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2585 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2586 RTLD_LOCAL, lockstate); 2587 } 2588 } 2589 2590 static void 2591 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2592 { 2593 if (obj->filtees_loaded || obj->filtees_loading) 2594 return; 2595 lock_restart_for_upgrade(lockstate); 2596 obj->filtees_loading = true; 2597 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2598 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2599 obj->filtees_loaded = true; 2600 obj->filtees_loading = false; 2601 } 2602 2603 static int 2604 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2605 { 2606 Obj_Entry *obj1; 2607 2608 for (; needed != NULL; needed = needed->next) { 2609 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2610 flags & ~RTLD_LO_NOLOAD); 2611 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2612 return (-1); 2613 } 2614 return (0); 2615 } 2616 2617 /* 2618 * Given a shared object, traverse its list of needed objects, and load 2619 * each of them. Returns 0 on success. Generates an error message and 2620 * returns -1 on failure. 2621 */ 2622 static int 2623 load_needed_objects(Obj_Entry *first, int flags) 2624 { 2625 Obj_Entry *obj; 2626 2627 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2628 if (obj->marker) 2629 continue; 2630 if (process_needed(obj, obj->needed, flags) == -1) 2631 return (-1); 2632 } 2633 return (0); 2634 } 2635 2636 static int 2637 load_preload_objects(const char *penv, bool isfd) 2638 { 2639 Obj_Entry *obj; 2640 const char *name; 2641 size_t len; 2642 char savech, *p, *psave; 2643 int fd; 2644 static const char delim[] = " \t:;"; 2645 2646 if (penv == NULL) 2647 return (0); 2648 2649 p = psave = xstrdup(penv); 2650 p += strspn(p, delim); 2651 while (*p != '\0') { 2652 len = strcspn(p, delim); 2653 2654 savech = p[len]; 2655 p[len] = '\0'; 2656 if (isfd) { 2657 name = NULL; 2658 fd = parse_integer(p); 2659 if (fd == -1) { 2660 free(psave); 2661 return (-1); 2662 } 2663 } else { 2664 name = p; 2665 fd = -1; 2666 } 2667 2668 obj = load_object(name, fd, NULL, 0); 2669 if (obj == NULL) { 2670 free(psave); 2671 return (-1); /* XXX - cleanup */ 2672 } 2673 obj->z_interpose = true; 2674 p[len] = savech; 2675 p += len; 2676 p += strspn(p, delim); 2677 } 2678 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2679 2680 free(psave); 2681 return (0); 2682 } 2683 2684 static const char * 2685 printable_path(const char *path) 2686 { 2687 2688 return (path == NULL ? "<unknown>" : path); 2689 } 2690 2691 /* 2692 * Load a shared object into memory, if it is not already loaded. The 2693 * object may be specified by name or by user-supplied file descriptor 2694 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2695 * duplicate is. 2696 * 2697 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2698 * on failure. 2699 */ 2700 static Obj_Entry * 2701 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2702 { 2703 Obj_Entry *obj; 2704 int fd; 2705 struct stat sb; 2706 char *path; 2707 2708 fd = -1; 2709 if (name != NULL) { 2710 TAILQ_FOREACH(obj, &obj_list, next) { 2711 if (obj->marker || obj->doomed) 2712 continue; 2713 if (object_match_name(obj, name)) 2714 return (obj); 2715 } 2716 2717 path = find_library(name, refobj, &fd); 2718 if (path == NULL) 2719 return (NULL); 2720 } else 2721 path = NULL; 2722 2723 if (fd >= 0) { 2724 /* 2725 * search_library_pathfds() opens a fresh file descriptor for the 2726 * library, so there is no need to dup(). 2727 */ 2728 } else if (fd_u == -1) { 2729 /* 2730 * If we didn't find a match by pathname, or the name is not 2731 * supplied, open the file and check again by device and inode. 2732 * This avoids false mismatches caused by multiple links or ".." 2733 * in pathnames. 2734 * 2735 * To avoid a race, we open the file and use fstat() rather than 2736 * using stat(). 2737 */ 2738 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2739 _rtld_error("Cannot open \"%s\"", path); 2740 free(path); 2741 return (NULL); 2742 } 2743 } else { 2744 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2745 if (fd == -1) { 2746 _rtld_error("Cannot dup fd"); 2747 free(path); 2748 return (NULL); 2749 } 2750 } 2751 if (fstat(fd, &sb) == -1) { 2752 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2753 close(fd); 2754 free(path); 2755 return (NULL); 2756 } 2757 TAILQ_FOREACH(obj, &obj_list, next) { 2758 if (obj->marker || obj->doomed) 2759 continue; 2760 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2761 break; 2762 } 2763 if (obj != NULL) { 2764 if (name != NULL) 2765 object_add_name(obj, name); 2766 free(path); 2767 close(fd); 2768 return (obj); 2769 } 2770 if (flags & RTLD_LO_NOLOAD) { 2771 free(path); 2772 close(fd); 2773 return (NULL); 2774 } 2775 2776 /* First use of this object, so we must map it in */ 2777 obj = do_load_object(fd, name, path, &sb, flags); 2778 if (obj == NULL) 2779 free(path); 2780 close(fd); 2781 2782 return (obj); 2783 } 2784 2785 static Obj_Entry * 2786 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2787 int flags) 2788 { 2789 Obj_Entry *obj; 2790 struct statfs fs; 2791 2792 /* 2793 * First, make sure that environment variables haven't been 2794 * used to circumvent the noexec flag on a filesystem. 2795 * We ignore fstatfs(2) failures, since fd might reference 2796 * not a file, e.g. shmfd. 2797 */ 2798 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2799 (fs.f_flags & MNT_NOEXEC) != 0) { 2800 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2801 return (NULL); 2802 } 2803 2804 dbg("loading \"%s\"", printable_path(path)); 2805 obj = map_object(fd, printable_path(path), sbp); 2806 if (obj == NULL) 2807 return (NULL); 2808 2809 /* 2810 * If DT_SONAME is present in the object, digest_dynamic2 already 2811 * added it to the object names. 2812 */ 2813 if (name != NULL) 2814 object_add_name(obj, name); 2815 obj->path = path; 2816 if (!digest_dynamic(obj, 0)) 2817 goto errp; 2818 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2819 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2820 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2821 dbg("refusing to load PIE executable \"%s\"", obj->path); 2822 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2823 goto errp; 2824 } 2825 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2826 RTLD_LO_DLOPEN) { 2827 dbg("refusing to load non-loadable \"%s\"", obj->path); 2828 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2829 goto errp; 2830 } 2831 2832 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2833 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2834 obj_count++; 2835 obj_loads++; 2836 linkmap_add(obj); /* for GDB & dlinfo() */ 2837 max_stack_flags |= obj->stack_flags; 2838 2839 dbg(" %p .. %p: %s", obj->mapbase, 2840 obj->mapbase + obj->mapsize - 1, obj->path); 2841 if (obj->textrel) 2842 dbg(" WARNING: %s has impure text", obj->path); 2843 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2844 obj->path); 2845 2846 return (obj); 2847 2848 errp: 2849 munmap(obj->mapbase, obj->mapsize); 2850 obj_free(obj); 2851 return (NULL); 2852 } 2853 2854 static int 2855 load_kpreload(const void *addr) 2856 { 2857 Obj_Entry *obj; 2858 const Elf_Ehdr *ehdr; 2859 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2860 static const char kname[] = "[vdso]"; 2861 2862 ehdr = addr; 2863 if (!check_elf_headers(ehdr, "kpreload")) 2864 return (-1); 2865 obj = obj_new(); 2866 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2867 obj->phdr = phdr; 2868 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2869 phlimit = phdr + ehdr->e_phnum; 2870 seg0 = segn = NULL; 2871 2872 for (; phdr < phlimit; phdr++) { 2873 switch (phdr->p_type) { 2874 case PT_DYNAMIC: 2875 phdyn = phdr; 2876 break; 2877 case PT_GNU_STACK: 2878 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2879 obj->stack_flags = phdr->p_flags; 2880 break; 2881 case PT_LOAD: 2882 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2883 seg0 = phdr; 2884 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2885 phdr->p_vaddr + phdr->p_memsz) 2886 segn = phdr; 2887 break; 2888 } 2889 } 2890 2891 obj->mapbase = __DECONST(caddr_t, addr); 2892 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2893 obj->vaddrbase = 0; 2894 obj->relocbase = obj->mapbase; 2895 2896 object_add_name(obj, kname); 2897 obj->path = xstrdup(kname); 2898 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2899 2900 if (!digest_dynamic(obj, 0)) { 2901 obj_free(obj); 2902 return (-1); 2903 } 2904 2905 /* 2906 * We assume that kernel-preloaded object does not need 2907 * relocation. It is currently written into read-only page, 2908 * handling relocations would mean we need to allocate at 2909 * least one additional page per AS. 2910 */ 2911 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2912 obj->path, obj->mapbase, obj->phdr, seg0, 2913 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2914 2915 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2916 obj_count++; 2917 obj_loads++; 2918 linkmap_add(obj); /* for GDB & dlinfo() */ 2919 max_stack_flags |= obj->stack_flags; 2920 2921 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2922 return (0); 2923 } 2924 2925 Obj_Entry * 2926 obj_from_addr(const void *addr) 2927 { 2928 Obj_Entry *obj; 2929 2930 TAILQ_FOREACH(obj, &obj_list, next) { 2931 if (obj->marker) 2932 continue; 2933 if (addr < (void *) obj->mapbase) 2934 continue; 2935 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2936 return obj; 2937 } 2938 return (NULL); 2939 } 2940 2941 static void 2942 preinit_main(void) 2943 { 2944 Elf_Addr *preinit_addr; 2945 int index; 2946 2947 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2948 if (preinit_addr == NULL) 2949 return; 2950 2951 for (index = 0; index < obj_main->preinit_array_num; index++) { 2952 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2953 dbg("calling preinit function for %s at %p", obj_main->path, 2954 (void *)preinit_addr[index]); 2955 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2956 0, 0, obj_main->path); 2957 call_init_pointer(obj_main, preinit_addr[index]); 2958 } 2959 } 2960 } 2961 2962 /* 2963 * Call the finalization functions for each of the objects in "list" 2964 * belonging to the DAG of "root" and referenced once. If NULL "root" 2965 * is specified, every finalization function will be called regardless 2966 * of the reference count and the list elements won't be freed. All of 2967 * the objects are expected to have non-NULL fini functions. 2968 */ 2969 static void 2970 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2971 { 2972 Objlist_Entry *elm; 2973 struct dlerror_save *saved_msg; 2974 Elf_Addr *fini_addr; 2975 int index; 2976 2977 assert(root == NULL || root->refcount == 1); 2978 2979 if (root != NULL) 2980 root->doomed = true; 2981 2982 /* 2983 * Preserve the current error message since a fini function might 2984 * call into the dynamic linker and overwrite it. 2985 */ 2986 saved_msg = errmsg_save(); 2987 do { 2988 STAILQ_FOREACH(elm, list, link) { 2989 if (root != NULL && (elm->obj->refcount != 1 || 2990 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2991 continue; 2992 /* Remove object from fini list to prevent recursive invocation. */ 2993 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2994 /* Ensure that new references cannot be acquired. */ 2995 elm->obj->doomed = true; 2996 2997 hold_object(elm->obj); 2998 lock_release(rtld_bind_lock, lockstate); 2999 /* 3000 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3001 * When this happens, DT_FINI_ARRAY is processed first. 3002 */ 3003 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3004 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3005 for (index = elm->obj->fini_array_num - 1; index >= 0; 3006 index--) { 3007 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3008 dbg("calling fini function for %s at %p", 3009 elm->obj->path, (void *)fini_addr[index]); 3010 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3011 (void *)fini_addr[index], 0, 0, elm->obj->path); 3012 call_initfini_pointer(elm->obj, fini_addr[index]); 3013 } 3014 } 3015 } 3016 if (elm->obj->fini != (Elf_Addr)NULL) { 3017 dbg("calling fini function for %s at %p", elm->obj->path, 3018 (void *)elm->obj->fini); 3019 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3020 0, 0, elm->obj->path); 3021 call_initfini_pointer(elm->obj, elm->obj->fini); 3022 } 3023 wlock_acquire(rtld_bind_lock, lockstate); 3024 unhold_object(elm->obj); 3025 /* No need to free anything if process is going down. */ 3026 if (root != NULL) 3027 free(elm); 3028 /* 3029 * We must restart the list traversal after every fini call 3030 * because a dlclose() call from the fini function or from 3031 * another thread might have modified the reference counts. 3032 */ 3033 break; 3034 } 3035 } while (elm != NULL); 3036 errmsg_restore(saved_msg); 3037 } 3038 3039 /* 3040 * Call the initialization functions for each of the objects in 3041 * "list". All of the objects are expected to have non-NULL init 3042 * functions. 3043 */ 3044 static void 3045 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3046 { 3047 Objlist_Entry *elm; 3048 Obj_Entry *obj; 3049 struct dlerror_save *saved_msg; 3050 Elf_Addr *init_addr; 3051 void (*reg)(void (*)(void)); 3052 int index; 3053 3054 /* 3055 * Clean init_scanned flag so that objects can be rechecked and 3056 * possibly initialized earlier if any of vectors called below 3057 * cause the change by using dlopen. 3058 */ 3059 TAILQ_FOREACH(obj, &obj_list, next) { 3060 if (obj->marker) 3061 continue; 3062 obj->init_scanned = false; 3063 } 3064 3065 /* 3066 * Preserve the current error message since an init function might 3067 * call into the dynamic linker and overwrite it. 3068 */ 3069 saved_msg = errmsg_save(); 3070 STAILQ_FOREACH(elm, list, link) { 3071 if (elm->obj->init_done) /* Initialized early. */ 3072 continue; 3073 /* 3074 * Race: other thread might try to use this object before current 3075 * one completes the initialization. Not much can be done here 3076 * without better locking. 3077 */ 3078 elm->obj->init_done = true; 3079 hold_object(elm->obj); 3080 reg = NULL; 3081 if (elm->obj == obj_main && obj_main->crt_no_init) { 3082 reg = (void (*)(void (*)(void)))get_program_var_addr( 3083 "__libc_atexit", lockstate); 3084 } 3085 lock_release(rtld_bind_lock, lockstate); 3086 if (reg != NULL) { 3087 reg(rtld_exit); 3088 rtld_exit_ptr = rtld_nop_exit; 3089 } 3090 3091 /* 3092 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3093 * When this happens, DT_INIT is processed first. 3094 */ 3095 if (elm->obj->init != (Elf_Addr)NULL) { 3096 dbg("calling init function for %s at %p", elm->obj->path, 3097 (void *)elm->obj->init); 3098 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3099 0, 0, elm->obj->path); 3100 call_init_pointer(elm->obj, elm->obj->init); 3101 } 3102 init_addr = (Elf_Addr *)elm->obj->init_array; 3103 if (init_addr != NULL) { 3104 for (index = 0; index < elm->obj->init_array_num; index++) { 3105 if (init_addr[index] != 0 && init_addr[index] != 1) { 3106 dbg("calling init function for %s at %p", elm->obj->path, 3107 (void *)init_addr[index]); 3108 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3109 (void *)init_addr[index], 0, 0, elm->obj->path); 3110 call_init_pointer(elm->obj, init_addr[index]); 3111 } 3112 } 3113 } 3114 wlock_acquire(rtld_bind_lock, lockstate); 3115 unhold_object(elm->obj); 3116 } 3117 errmsg_restore(saved_msg); 3118 } 3119 3120 static void 3121 objlist_clear(Objlist *list) 3122 { 3123 Objlist_Entry *elm; 3124 3125 while (!STAILQ_EMPTY(list)) { 3126 elm = STAILQ_FIRST(list); 3127 STAILQ_REMOVE_HEAD(list, link); 3128 free(elm); 3129 } 3130 } 3131 3132 static Objlist_Entry * 3133 objlist_find(Objlist *list, const Obj_Entry *obj) 3134 { 3135 Objlist_Entry *elm; 3136 3137 STAILQ_FOREACH(elm, list, link) 3138 if (elm->obj == obj) 3139 return elm; 3140 return (NULL); 3141 } 3142 3143 static void 3144 objlist_init(Objlist *list) 3145 { 3146 STAILQ_INIT(list); 3147 } 3148 3149 static void 3150 objlist_push_head(Objlist *list, Obj_Entry *obj) 3151 { 3152 Objlist_Entry *elm; 3153 3154 elm = NEW(Objlist_Entry); 3155 elm->obj = obj; 3156 STAILQ_INSERT_HEAD(list, elm, link); 3157 } 3158 3159 static void 3160 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3161 { 3162 Objlist_Entry *elm; 3163 3164 elm = NEW(Objlist_Entry); 3165 elm->obj = obj; 3166 STAILQ_INSERT_TAIL(list, elm, link); 3167 } 3168 3169 static void 3170 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3171 { 3172 Objlist_Entry *elm, *listelm; 3173 3174 STAILQ_FOREACH(listelm, list, link) { 3175 if (listelm->obj == listobj) 3176 break; 3177 } 3178 elm = NEW(Objlist_Entry); 3179 elm->obj = obj; 3180 if (listelm != NULL) 3181 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3182 else 3183 STAILQ_INSERT_TAIL(list, elm, link); 3184 } 3185 3186 static void 3187 objlist_remove(Objlist *list, Obj_Entry *obj) 3188 { 3189 Objlist_Entry *elm; 3190 3191 if ((elm = objlist_find(list, obj)) != NULL) { 3192 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3193 free(elm); 3194 } 3195 } 3196 3197 /* 3198 * Relocate dag rooted in the specified object. 3199 * Returns 0 on success, or -1 on failure. 3200 */ 3201 3202 static int 3203 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3204 int flags, RtldLockState *lockstate) 3205 { 3206 Objlist_Entry *elm; 3207 int error; 3208 3209 error = 0; 3210 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3211 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3212 lockstate); 3213 if (error == -1) 3214 break; 3215 } 3216 return (error); 3217 } 3218 3219 /* 3220 * Prepare for, or clean after, relocating an object marked with 3221 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3222 * segments are remapped read-write. After relocations are done, the 3223 * segment's permissions are returned back to the modes specified in 3224 * the phdrs. If any relocation happened, or always for wired 3225 * program, COW is triggered. 3226 */ 3227 static int 3228 reloc_textrel_prot(Obj_Entry *obj, bool before) 3229 { 3230 const Elf_Phdr *ph; 3231 void *base; 3232 size_t l, sz; 3233 int prot; 3234 3235 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3236 l--, ph++) { 3237 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3238 continue; 3239 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3240 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3241 rtld_trunc_page(ph->p_vaddr); 3242 prot = before ? (PROT_READ | PROT_WRITE) : 3243 convert_prot(ph->p_flags); 3244 if (mprotect(base, sz, prot) == -1) { 3245 _rtld_error("%s: Cannot write-%sable text segment: %s", 3246 obj->path, before ? "en" : "dis", 3247 rtld_strerror(errno)); 3248 return (-1); 3249 } 3250 } 3251 return (0); 3252 } 3253 3254 /* Process RELR relative relocations. */ 3255 static void 3256 reloc_relr(Obj_Entry *obj) 3257 { 3258 const Elf_Relr *relr, *relrlim; 3259 Elf_Addr *where; 3260 3261 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3262 for (relr = obj->relr; relr < relrlim; relr++) { 3263 Elf_Relr entry = *relr; 3264 3265 if ((entry & 1) == 0) { 3266 where = (Elf_Addr *)(obj->relocbase + entry); 3267 *where++ += (Elf_Addr)obj->relocbase; 3268 } else { 3269 for (long i = 0; (entry >>= 1) != 0; i++) 3270 if ((entry & 1) != 0) 3271 where[i] += (Elf_Addr)obj->relocbase; 3272 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3273 } 3274 } 3275 } 3276 3277 /* 3278 * Relocate single object. 3279 * Returns 0 on success, or -1 on failure. 3280 */ 3281 static int 3282 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3283 int flags, RtldLockState *lockstate) 3284 { 3285 3286 if (obj->relocated) 3287 return (0); 3288 obj->relocated = true; 3289 if (obj != rtldobj) 3290 dbg("relocating \"%s\"", obj->path); 3291 3292 if (obj->symtab == NULL || obj->strtab == NULL || 3293 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3294 dbg("object %s has no run-time symbol table", obj->path); 3295 3296 /* There are relocations to the write-protected text segment. */ 3297 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3298 return (-1); 3299 3300 /* Process the non-PLT non-IFUNC relocations. */ 3301 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3302 return (-1); 3303 reloc_relr(obj); 3304 3305 /* Re-protected the text segment. */ 3306 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3307 return (-1); 3308 3309 /* Set the special PLT or GOT entries. */ 3310 init_pltgot(obj); 3311 3312 /* Process the PLT relocations. */ 3313 if (reloc_plt(obj, flags, lockstate) == -1) 3314 return (-1); 3315 /* Relocate the jump slots if we are doing immediate binding. */ 3316 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3317 lockstate) == -1) 3318 return (-1); 3319 3320 if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1) 3321 return (-1); 3322 3323 /* 3324 * Set up the magic number and version in the Obj_Entry. These 3325 * were checked in the crt1.o from the original ElfKit, so we 3326 * set them for backward compatibility. 3327 */ 3328 obj->magic = RTLD_MAGIC; 3329 obj->version = RTLD_VERSION; 3330 3331 return (0); 3332 } 3333 3334 /* 3335 * Relocate newly-loaded shared objects. The argument is a pointer to 3336 * the Obj_Entry for the first such object. All objects from the first 3337 * to the end of the list of objects are relocated. Returns 0 on success, 3338 * or -1 on failure. 3339 */ 3340 static int 3341 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3342 int flags, RtldLockState *lockstate) 3343 { 3344 Obj_Entry *obj; 3345 int error; 3346 3347 for (error = 0, obj = first; obj != NULL; 3348 obj = TAILQ_NEXT(obj, next)) { 3349 if (obj->marker) 3350 continue; 3351 error = relocate_object(obj, bind_now, rtldobj, flags, 3352 lockstate); 3353 if (error == -1) 3354 break; 3355 } 3356 return (error); 3357 } 3358 3359 /* 3360 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3361 * referencing STT_GNU_IFUNC symbols is postponed till the other 3362 * relocations are done. The indirect functions specified as 3363 * ifunc are allowed to call other symbols, so we need to have 3364 * objects relocated before asking for resolution from indirects. 3365 * 3366 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3367 * instead of the usual lazy handling of PLT slots. It is 3368 * consistent with how GNU does it. 3369 */ 3370 static int 3371 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3372 RtldLockState *lockstate) 3373 { 3374 3375 if (obj->ifuncs_resolved) 3376 return (0); 3377 obj->ifuncs_resolved = true; 3378 if (!obj->irelative && !obj->irelative_nonplt && 3379 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3380 !obj->non_plt_gnu_ifunc) 3381 return (0); 3382 if (obj_disable_relro(obj) == -1 || 3383 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3384 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3385 lockstate) == -1) || 3386 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3387 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3388 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3389 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3390 obj_enforce_relro(obj) == -1) 3391 return (-1); 3392 return (0); 3393 } 3394 3395 static int 3396 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3397 RtldLockState *lockstate) 3398 { 3399 Objlist_Entry *elm; 3400 Obj_Entry *obj; 3401 3402 STAILQ_FOREACH(elm, list, link) { 3403 obj = elm->obj; 3404 if (obj->marker) 3405 continue; 3406 if (resolve_object_ifunc(obj, bind_now, flags, 3407 lockstate) == -1) 3408 return (-1); 3409 } 3410 return (0); 3411 } 3412 3413 /* 3414 * Cleanup procedure. It will be called (by the atexit mechanism) just 3415 * before the process exits. 3416 */ 3417 static void 3418 rtld_exit(void) 3419 { 3420 RtldLockState lockstate; 3421 3422 wlock_acquire(rtld_bind_lock, &lockstate); 3423 dbg("rtld_exit()"); 3424 objlist_call_fini(&list_fini, NULL, &lockstate); 3425 /* No need to remove the items from the list, since we are exiting. */ 3426 if (!libmap_disable) 3427 lm_fini(); 3428 lock_release(rtld_bind_lock, &lockstate); 3429 } 3430 3431 static void 3432 rtld_nop_exit(void) 3433 { 3434 } 3435 3436 /* 3437 * Iterate over a search path, translate each element, and invoke the 3438 * callback on the result. 3439 */ 3440 static void * 3441 path_enumerate(const char *path, path_enum_proc callback, 3442 const char *refobj_path, void *arg) 3443 { 3444 const char *trans; 3445 if (path == NULL) 3446 return (NULL); 3447 3448 path += strspn(path, ":;"); 3449 while (*path != '\0') { 3450 size_t len; 3451 char *res; 3452 3453 len = strcspn(path, ":;"); 3454 trans = lm_findn(refobj_path, path, len); 3455 if (trans) 3456 res = callback(trans, strlen(trans), arg); 3457 else 3458 res = callback(path, len, arg); 3459 3460 if (res != NULL) 3461 return (res); 3462 3463 path += len; 3464 path += strspn(path, ":;"); 3465 } 3466 3467 return (NULL); 3468 } 3469 3470 struct try_library_args { 3471 const char *name; 3472 size_t namelen; 3473 char *buffer; 3474 size_t buflen; 3475 int fd; 3476 }; 3477 3478 static void * 3479 try_library_path(const char *dir, size_t dirlen, void *param) 3480 { 3481 struct try_library_args *arg; 3482 int fd; 3483 3484 arg = param; 3485 if (*dir == '/' || trust) { 3486 char *pathname; 3487 3488 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3489 return (NULL); 3490 3491 pathname = arg->buffer; 3492 strncpy(pathname, dir, dirlen); 3493 pathname[dirlen] = '/'; 3494 strcpy(pathname + dirlen + 1, arg->name); 3495 3496 dbg(" Trying \"%s\"", pathname); 3497 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3498 if (fd >= 0) { 3499 dbg(" Opened \"%s\", fd %d", pathname, fd); 3500 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3501 strcpy(pathname, arg->buffer); 3502 arg->fd = fd; 3503 return (pathname); 3504 } else { 3505 dbg(" Failed to open \"%s\": %s", 3506 pathname, rtld_strerror(errno)); 3507 } 3508 } 3509 return (NULL); 3510 } 3511 3512 static char * 3513 search_library_path(const char *name, const char *path, 3514 const char *refobj_path, int *fdp) 3515 { 3516 char *p; 3517 struct try_library_args arg; 3518 3519 if (path == NULL) 3520 return (NULL); 3521 3522 arg.name = name; 3523 arg.namelen = strlen(name); 3524 arg.buffer = xmalloc(PATH_MAX); 3525 arg.buflen = PATH_MAX; 3526 arg.fd = -1; 3527 3528 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3529 *fdp = arg.fd; 3530 3531 free(arg.buffer); 3532 3533 return (p); 3534 } 3535 3536 3537 /* 3538 * Finds the library with the given name using the directory descriptors 3539 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3540 * 3541 * Returns a freshly-opened close-on-exec file descriptor for the library, 3542 * or -1 if the library cannot be found. 3543 */ 3544 static char * 3545 search_library_pathfds(const char *name, const char *path, int *fdp) 3546 { 3547 char *envcopy, *fdstr, *found, *last_token; 3548 size_t len; 3549 int dirfd, fd; 3550 3551 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3552 3553 /* Don't load from user-specified libdirs into setuid binaries. */ 3554 if (!trust) 3555 return (NULL); 3556 3557 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3558 if (path == NULL) 3559 return (NULL); 3560 3561 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3562 if (name[0] == '/') { 3563 dbg("Absolute path (%s) passed to %s", name, __func__); 3564 return (NULL); 3565 } 3566 3567 /* 3568 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3569 * copy of the path, as strtok_r rewrites separator tokens 3570 * with '\0'. 3571 */ 3572 found = NULL; 3573 envcopy = xstrdup(path); 3574 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3575 fdstr = strtok_r(NULL, ":", &last_token)) { 3576 dirfd = parse_integer(fdstr); 3577 if (dirfd < 0) { 3578 _rtld_error("failed to parse directory FD: '%s'", 3579 fdstr); 3580 break; 3581 } 3582 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3583 if (fd >= 0) { 3584 *fdp = fd; 3585 len = strlen(fdstr) + strlen(name) + 3; 3586 found = xmalloc(len); 3587 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3588 _rtld_error("error generating '%d/%s'", 3589 dirfd, name); 3590 rtld_die(); 3591 } 3592 dbg("open('%s') => %d", found, fd); 3593 break; 3594 } 3595 } 3596 free(envcopy); 3597 3598 return (found); 3599 } 3600 3601 3602 int 3603 dlclose(void *handle) 3604 { 3605 RtldLockState lockstate; 3606 int error; 3607 3608 wlock_acquire(rtld_bind_lock, &lockstate); 3609 error = dlclose_locked(handle, &lockstate); 3610 lock_release(rtld_bind_lock, &lockstate); 3611 return (error); 3612 } 3613 3614 static int 3615 dlclose_locked(void *handle, RtldLockState *lockstate) 3616 { 3617 Obj_Entry *root; 3618 3619 root = dlcheck(handle); 3620 if (root == NULL) 3621 return (-1); 3622 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3623 root->path); 3624 3625 /* Unreference the object and its dependencies. */ 3626 root->dl_refcount--; 3627 3628 if (root->refcount == 1) { 3629 /* 3630 * The object will be no longer referenced, so we must unload it. 3631 * First, call the fini functions. 3632 */ 3633 objlist_call_fini(&list_fini, root, lockstate); 3634 3635 unref_dag(root); 3636 3637 /* Finish cleaning up the newly-unreferenced objects. */ 3638 GDB_STATE(RT_DELETE,&root->linkmap); 3639 unload_object(root, lockstate); 3640 GDB_STATE(RT_CONSISTENT,NULL); 3641 } else 3642 unref_dag(root); 3643 3644 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3645 return (0); 3646 } 3647 3648 char * 3649 dlerror(void) 3650 { 3651 if (*(lockinfo.dlerror_seen()) != 0) 3652 return (NULL); 3653 *lockinfo.dlerror_seen() = 1; 3654 return (lockinfo.dlerror_loc()); 3655 } 3656 3657 /* 3658 * This function is deprecated and has no effect. 3659 */ 3660 void 3661 dllockinit(void *context, 3662 void *(*_lock_create)(void *context) __unused, 3663 void (*_rlock_acquire)(void *lock) __unused, 3664 void (*_wlock_acquire)(void *lock) __unused, 3665 void (*_lock_release)(void *lock) __unused, 3666 void (*_lock_destroy)(void *lock) __unused, 3667 void (*context_destroy)(void *context)) 3668 { 3669 static void *cur_context; 3670 static void (*cur_context_destroy)(void *); 3671 3672 /* Just destroy the context from the previous call, if necessary. */ 3673 if (cur_context_destroy != NULL) 3674 cur_context_destroy(cur_context); 3675 cur_context = context; 3676 cur_context_destroy = context_destroy; 3677 } 3678 3679 void * 3680 dlopen(const char *name, int mode) 3681 { 3682 3683 return (rtld_dlopen(name, -1, mode)); 3684 } 3685 3686 void * 3687 fdlopen(int fd, int mode) 3688 { 3689 3690 return (rtld_dlopen(NULL, fd, mode)); 3691 } 3692 3693 static void * 3694 rtld_dlopen(const char *name, int fd, int mode) 3695 { 3696 RtldLockState lockstate; 3697 int lo_flags; 3698 3699 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3700 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3701 if (ld_tracing != NULL) { 3702 rlock_acquire(rtld_bind_lock, &lockstate); 3703 if (sigsetjmp(lockstate.env, 0) != 0) 3704 lock_upgrade(rtld_bind_lock, &lockstate); 3705 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3706 lock_release(rtld_bind_lock, &lockstate); 3707 } 3708 lo_flags = RTLD_LO_DLOPEN; 3709 if (mode & RTLD_NODELETE) 3710 lo_flags |= RTLD_LO_NODELETE; 3711 if (mode & RTLD_NOLOAD) 3712 lo_flags |= RTLD_LO_NOLOAD; 3713 if (mode & RTLD_DEEPBIND) 3714 lo_flags |= RTLD_LO_DEEPBIND; 3715 if (ld_tracing != NULL) 3716 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3717 3718 return (dlopen_object(name, fd, obj_main, lo_flags, 3719 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3720 } 3721 3722 static void 3723 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3724 { 3725 3726 obj->dl_refcount--; 3727 unref_dag(obj); 3728 if (obj->refcount == 0) 3729 unload_object(obj, lockstate); 3730 } 3731 3732 static Obj_Entry * 3733 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3734 int mode, RtldLockState *lockstate) 3735 { 3736 Obj_Entry *obj; 3737 Objlist initlist; 3738 RtldLockState mlockstate; 3739 int result; 3740 3741 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3742 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3743 refobj->path, lo_flags, mode); 3744 objlist_init(&initlist); 3745 3746 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3747 wlock_acquire(rtld_bind_lock, &mlockstate); 3748 lockstate = &mlockstate; 3749 } 3750 GDB_STATE(RT_ADD,NULL); 3751 3752 obj = NULL; 3753 if (name == NULL && fd == -1) { 3754 obj = obj_main; 3755 obj->refcount++; 3756 } else { 3757 obj = load_object(name, fd, refobj, lo_flags); 3758 } 3759 3760 if (obj) { 3761 obj->dl_refcount++; 3762 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3763 objlist_push_tail(&list_global, obj); 3764 3765 if (!obj->init_done) { 3766 /* We loaded something new and have to init something. */ 3767 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3768 obj->deepbind = true; 3769 result = 0; 3770 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3771 obj->static_tls && !allocate_tls_offset(obj)) { 3772 _rtld_error("%s: No space available " 3773 "for static Thread Local Storage", obj->path); 3774 result = -1; 3775 } 3776 if (result != -1) 3777 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3778 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3779 init_dag(obj); 3780 ref_dag(obj); 3781 if (result != -1) 3782 result = rtld_verify_versions(&obj->dagmembers); 3783 if (result != -1 && ld_tracing) 3784 goto trace; 3785 if (result == -1 || relocate_object_dag(obj, 3786 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3787 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3788 lockstate) == -1) { 3789 dlopen_cleanup(obj, lockstate); 3790 obj = NULL; 3791 } else if (lo_flags & RTLD_LO_EARLY) { 3792 /* 3793 * Do not call the init functions for early loaded 3794 * filtees. The image is still not initialized enough 3795 * for them to work. 3796 * 3797 * Our object is found by the global object list and 3798 * will be ordered among all init calls done right 3799 * before transferring control to main. 3800 */ 3801 } else { 3802 /* Make list of init functions to call. */ 3803 initlist_add_objects(obj, obj, &initlist); 3804 } 3805 /* 3806 * Process all no_delete or global objects here, given 3807 * them own DAGs to prevent their dependencies from being 3808 * unloaded. This has to be done after we have loaded all 3809 * of the dependencies, so that we do not miss any. 3810 */ 3811 if (obj != NULL) 3812 process_z(obj); 3813 } else { 3814 /* 3815 * Bump the reference counts for objects on this DAG. If 3816 * this is the first dlopen() call for the object that was 3817 * already loaded as a dependency, initialize the dag 3818 * starting at it. 3819 */ 3820 init_dag(obj); 3821 ref_dag(obj); 3822 3823 if ((lo_flags & RTLD_LO_TRACE) != 0) 3824 goto trace; 3825 } 3826 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3827 obj->z_nodelete) && !obj->ref_nodel) { 3828 dbg("obj %s nodelete", obj->path); 3829 ref_dag(obj); 3830 obj->z_nodelete = obj->ref_nodel = true; 3831 } 3832 } 3833 3834 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3835 name); 3836 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3837 3838 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3839 map_stacks_exec(lockstate); 3840 if (obj != NULL) 3841 distribute_static_tls(&initlist, lockstate); 3842 } 3843 3844 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3845 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3846 lockstate) == -1) { 3847 objlist_clear(&initlist); 3848 dlopen_cleanup(obj, lockstate); 3849 if (lockstate == &mlockstate) 3850 lock_release(rtld_bind_lock, lockstate); 3851 return (NULL); 3852 } 3853 3854 if (!(lo_flags & RTLD_LO_EARLY)) { 3855 /* Call the init functions. */ 3856 objlist_call_init(&initlist, lockstate); 3857 } 3858 objlist_clear(&initlist); 3859 if (lockstate == &mlockstate) 3860 lock_release(rtld_bind_lock, lockstate); 3861 return (obj); 3862 trace: 3863 trace_loaded_objects(obj, false); 3864 if (lockstate == &mlockstate) 3865 lock_release(rtld_bind_lock, lockstate); 3866 exit(0); 3867 } 3868 3869 static void * 3870 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3871 int flags) 3872 { 3873 DoneList donelist; 3874 const Obj_Entry *obj, *defobj; 3875 const Elf_Sym *def; 3876 SymLook req; 3877 RtldLockState lockstate; 3878 tls_index ti; 3879 void *sym; 3880 int res; 3881 3882 def = NULL; 3883 defobj = NULL; 3884 symlook_init(&req, name); 3885 req.ventry = ve; 3886 req.flags = flags | SYMLOOK_IN_PLT; 3887 req.lockstate = &lockstate; 3888 3889 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3890 rlock_acquire(rtld_bind_lock, &lockstate); 3891 if (sigsetjmp(lockstate.env, 0) != 0) 3892 lock_upgrade(rtld_bind_lock, &lockstate); 3893 if (handle == NULL || handle == RTLD_NEXT || 3894 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3895 3896 if ((obj = obj_from_addr(retaddr)) == NULL) { 3897 _rtld_error("Cannot determine caller's shared object"); 3898 lock_release(rtld_bind_lock, &lockstate); 3899 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3900 return (NULL); 3901 } 3902 if (handle == NULL) { /* Just the caller's shared object. */ 3903 res = symlook_obj(&req, obj); 3904 if (res == 0) { 3905 def = req.sym_out; 3906 defobj = req.defobj_out; 3907 } 3908 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3909 handle == RTLD_SELF) { /* ... caller included */ 3910 if (handle == RTLD_NEXT) 3911 obj = globallist_next(obj); 3912 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3913 if (obj->marker) 3914 continue; 3915 res = symlook_obj(&req, obj); 3916 if (res == 0) { 3917 if (def == NULL || (ld_dynamic_weak && 3918 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3919 def = req.sym_out; 3920 defobj = req.defobj_out; 3921 if (!ld_dynamic_weak || 3922 ELF_ST_BIND(def->st_info) != STB_WEAK) 3923 break; 3924 } 3925 } 3926 } 3927 /* 3928 * Search the dynamic linker itself, and possibly resolve the 3929 * symbol from there. This is how the application links to 3930 * dynamic linker services such as dlopen. 3931 * Note that we ignore ld_dynamic_weak == false case, 3932 * always overriding weak symbols by rtld definitions. 3933 */ 3934 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3935 res = symlook_obj(&req, &obj_rtld); 3936 if (res == 0) { 3937 def = req.sym_out; 3938 defobj = req.defobj_out; 3939 } 3940 } 3941 } else { 3942 assert(handle == RTLD_DEFAULT); 3943 res = symlook_default(&req, obj); 3944 if (res == 0) { 3945 defobj = req.defobj_out; 3946 def = req.sym_out; 3947 } 3948 } 3949 } else { 3950 if ((obj = dlcheck(handle)) == NULL) { 3951 lock_release(rtld_bind_lock, &lockstate); 3952 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3953 return (NULL); 3954 } 3955 3956 donelist_init(&donelist); 3957 if (obj->mainprog) { 3958 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3959 res = symlook_global(&req, &donelist); 3960 if (res == 0) { 3961 def = req.sym_out; 3962 defobj = req.defobj_out; 3963 } 3964 /* 3965 * Search the dynamic linker itself, and possibly resolve the 3966 * symbol from there. This is how the application links to 3967 * dynamic linker services such as dlopen. 3968 */ 3969 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3970 res = symlook_obj(&req, &obj_rtld); 3971 if (res == 0) { 3972 def = req.sym_out; 3973 defobj = req.defobj_out; 3974 } 3975 } 3976 } 3977 else { 3978 /* Search the whole DAG rooted at the given object. */ 3979 res = symlook_list(&req, &obj->dagmembers, &donelist); 3980 if (res == 0) { 3981 def = req.sym_out; 3982 defobj = req.defobj_out; 3983 } 3984 } 3985 } 3986 3987 if (def != NULL) { 3988 lock_release(rtld_bind_lock, &lockstate); 3989 3990 /* 3991 * The value required by the caller is derived from the value 3992 * of the symbol. this is simply the relocated value of the 3993 * symbol. 3994 */ 3995 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3996 sym = make_function_pointer(def, defobj); 3997 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3998 sym = rtld_resolve_ifunc(defobj, def); 3999 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4000 ti.ti_module = defobj->tlsindex; 4001 ti.ti_offset = def->st_value; 4002 sym = __tls_get_addr(&ti); 4003 } else 4004 sym = defobj->relocbase + def->st_value; 4005 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4006 return (sym); 4007 } 4008 4009 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4010 ve != NULL ? ve->name : ""); 4011 lock_release(rtld_bind_lock, &lockstate); 4012 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4013 return (NULL); 4014 } 4015 4016 void * 4017 dlsym(void *handle, const char *name) 4018 { 4019 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4020 SYMLOOK_DLSYM)); 4021 } 4022 4023 dlfunc_t 4024 dlfunc(void *handle, const char *name) 4025 { 4026 union { 4027 void *d; 4028 dlfunc_t f; 4029 } rv; 4030 4031 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4032 SYMLOOK_DLSYM); 4033 return (rv.f); 4034 } 4035 4036 void * 4037 dlvsym(void *handle, const char *name, const char *version) 4038 { 4039 Ver_Entry ventry; 4040 4041 ventry.name = version; 4042 ventry.file = NULL; 4043 ventry.hash = elf_hash(version); 4044 ventry.flags= 0; 4045 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4046 SYMLOOK_DLSYM)); 4047 } 4048 4049 int 4050 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4051 { 4052 const Obj_Entry *obj; 4053 RtldLockState lockstate; 4054 4055 rlock_acquire(rtld_bind_lock, &lockstate); 4056 obj = obj_from_addr(addr); 4057 if (obj == NULL) { 4058 _rtld_error("No shared object contains address"); 4059 lock_release(rtld_bind_lock, &lockstate); 4060 return (0); 4061 } 4062 rtld_fill_dl_phdr_info(obj, phdr_info); 4063 lock_release(rtld_bind_lock, &lockstate); 4064 return (1); 4065 } 4066 4067 int 4068 dladdr(const void *addr, Dl_info *info) 4069 { 4070 const Obj_Entry *obj; 4071 const Elf_Sym *def; 4072 void *symbol_addr; 4073 unsigned long symoffset; 4074 RtldLockState lockstate; 4075 4076 rlock_acquire(rtld_bind_lock, &lockstate); 4077 obj = obj_from_addr(addr); 4078 if (obj == NULL) { 4079 _rtld_error("No shared object contains address"); 4080 lock_release(rtld_bind_lock, &lockstate); 4081 return (0); 4082 } 4083 info->dli_fname = obj->path; 4084 info->dli_fbase = obj->mapbase; 4085 info->dli_saddr = (void *)0; 4086 info->dli_sname = NULL; 4087 4088 /* 4089 * Walk the symbol list looking for the symbol whose address is 4090 * closest to the address sent in. 4091 */ 4092 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4093 def = obj->symtab + symoffset; 4094 4095 /* 4096 * For skip the symbol if st_shndx is either SHN_UNDEF or 4097 * SHN_COMMON. 4098 */ 4099 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4100 continue; 4101 4102 /* 4103 * If the symbol is greater than the specified address, or if it 4104 * is further away from addr than the current nearest symbol, 4105 * then reject it. 4106 */ 4107 symbol_addr = obj->relocbase + def->st_value; 4108 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4109 continue; 4110 4111 /* Update our idea of the nearest symbol. */ 4112 info->dli_sname = obj->strtab + def->st_name; 4113 info->dli_saddr = symbol_addr; 4114 4115 /* Exact match? */ 4116 if (info->dli_saddr == addr) 4117 break; 4118 } 4119 lock_release(rtld_bind_lock, &lockstate); 4120 return (1); 4121 } 4122 4123 int 4124 dlinfo(void *handle, int request, void *p) 4125 { 4126 const Obj_Entry *obj; 4127 RtldLockState lockstate; 4128 int error; 4129 4130 rlock_acquire(rtld_bind_lock, &lockstate); 4131 4132 if (handle == NULL || handle == RTLD_SELF) { 4133 void *retaddr; 4134 4135 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4136 if ((obj = obj_from_addr(retaddr)) == NULL) 4137 _rtld_error("Cannot determine caller's shared object"); 4138 } else 4139 obj = dlcheck(handle); 4140 4141 if (obj == NULL) { 4142 lock_release(rtld_bind_lock, &lockstate); 4143 return (-1); 4144 } 4145 4146 error = 0; 4147 switch (request) { 4148 case RTLD_DI_LINKMAP: 4149 *((struct link_map const **)p) = &obj->linkmap; 4150 break; 4151 case RTLD_DI_ORIGIN: 4152 error = rtld_dirname(obj->path, p); 4153 break; 4154 4155 case RTLD_DI_SERINFOSIZE: 4156 case RTLD_DI_SERINFO: 4157 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4158 break; 4159 4160 default: 4161 _rtld_error("Invalid request %d passed to dlinfo()", request); 4162 error = -1; 4163 } 4164 4165 lock_release(rtld_bind_lock, &lockstate); 4166 4167 return (error); 4168 } 4169 4170 static void 4171 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4172 { 4173 uintptr_t **dtvp; 4174 4175 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4176 phdr_info->dlpi_name = obj->path; 4177 phdr_info->dlpi_phdr = obj->phdr; 4178 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4179 phdr_info->dlpi_tls_modid = obj->tlsindex; 4180 dtvp = &_tcb_get()->tcb_dtv; 4181 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4182 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4183 phdr_info->dlpi_adds = obj_loads; 4184 phdr_info->dlpi_subs = obj_loads - obj_count; 4185 } 4186 4187 /* 4188 * It's completely UB to actually use this, so extreme caution is advised. It's 4189 * probably not what you want. 4190 */ 4191 int 4192 _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param) 4193 { 4194 struct dl_phdr_info phdr_info; 4195 Obj_Entry *obj; 4196 int error; 4197 4198 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL; 4199 obj = globallist_next(obj)) { 4200 rtld_fill_dl_phdr_info(obj, &phdr_info); 4201 error = callback(&phdr_info, sizeof(phdr_info), param); 4202 if (error != 0) 4203 return (error); 4204 } 4205 4206 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4207 return (callback(&phdr_info, sizeof(phdr_info), param)); 4208 } 4209 4210 int 4211 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4212 { 4213 struct dl_phdr_info phdr_info; 4214 Obj_Entry *obj, marker; 4215 RtldLockState bind_lockstate, phdr_lockstate; 4216 int error; 4217 4218 init_marker(&marker); 4219 error = 0; 4220 4221 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4222 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4223 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4224 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4225 rtld_fill_dl_phdr_info(obj, &phdr_info); 4226 hold_object(obj); 4227 lock_release(rtld_bind_lock, &bind_lockstate); 4228 4229 error = callback(&phdr_info, sizeof phdr_info, param); 4230 4231 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4232 unhold_object(obj); 4233 obj = globallist_next(&marker); 4234 TAILQ_REMOVE(&obj_list, &marker, next); 4235 if (error != 0) { 4236 lock_release(rtld_bind_lock, &bind_lockstate); 4237 lock_release(rtld_phdr_lock, &phdr_lockstate); 4238 return (error); 4239 } 4240 } 4241 4242 if (error == 0) { 4243 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4244 lock_release(rtld_bind_lock, &bind_lockstate); 4245 error = callback(&phdr_info, sizeof(phdr_info), param); 4246 } 4247 lock_release(rtld_phdr_lock, &phdr_lockstate); 4248 return (error); 4249 } 4250 4251 static void * 4252 fill_search_info(const char *dir, size_t dirlen, void *param) 4253 { 4254 struct fill_search_info_args *arg; 4255 4256 arg = param; 4257 4258 if (arg->request == RTLD_DI_SERINFOSIZE) { 4259 arg->serinfo->dls_cnt ++; 4260 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4261 } else { 4262 struct dl_serpath *s_entry; 4263 4264 s_entry = arg->serpath; 4265 s_entry->dls_name = arg->strspace; 4266 s_entry->dls_flags = arg->flags; 4267 4268 strncpy(arg->strspace, dir, dirlen); 4269 arg->strspace[dirlen] = '\0'; 4270 4271 arg->strspace += dirlen + 1; 4272 arg->serpath++; 4273 } 4274 4275 return (NULL); 4276 } 4277 4278 static int 4279 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4280 { 4281 struct dl_serinfo _info; 4282 struct fill_search_info_args args; 4283 4284 args.request = RTLD_DI_SERINFOSIZE; 4285 args.serinfo = &_info; 4286 4287 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4288 _info.dls_cnt = 0; 4289 4290 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4291 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4292 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4293 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4294 if (!obj->z_nodeflib) 4295 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4296 4297 4298 if (request == RTLD_DI_SERINFOSIZE) { 4299 info->dls_size = _info.dls_size; 4300 info->dls_cnt = _info.dls_cnt; 4301 return (0); 4302 } 4303 4304 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4305 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4306 return (-1); 4307 } 4308 4309 args.request = RTLD_DI_SERINFO; 4310 args.serinfo = info; 4311 args.serpath = &info->dls_serpath[0]; 4312 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4313 4314 args.flags = LA_SER_RUNPATH; 4315 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4316 return (-1); 4317 4318 args.flags = LA_SER_LIBPATH; 4319 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4320 return (-1); 4321 4322 args.flags = LA_SER_RUNPATH; 4323 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4324 return (-1); 4325 4326 args.flags = LA_SER_CONFIG; 4327 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4328 != NULL) 4329 return (-1); 4330 4331 args.flags = LA_SER_DEFAULT; 4332 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4333 fill_search_info, NULL, &args) != NULL) 4334 return (-1); 4335 return (0); 4336 } 4337 4338 static int 4339 rtld_dirname(const char *path, char *bname) 4340 { 4341 const char *endp; 4342 4343 /* Empty or NULL string gets treated as "." */ 4344 if (path == NULL || *path == '\0') { 4345 bname[0] = '.'; 4346 bname[1] = '\0'; 4347 return (0); 4348 } 4349 4350 /* Strip trailing slashes */ 4351 endp = path + strlen(path) - 1; 4352 while (endp > path && *endp == '/') 4353 endp--; 4354 4355 /* Find the start of the dir */ 4356 while (endp > path && *endp != '/') 4357 endp--; 4358 4359 /* Either the dir is "/" or there are no slashes */ 4360 if (endp == path) { 4361 bname[0] = *endp == '/' ? '/' : '.'; 4362 bname[1] = '\0'; 4363 return (0); 4364 } else { 4365 do { 4366 endp--; 4367 } while (endp > path && *endp == '/'); 4368 } 4369 4370 if (endp - path + 2 > PATH_MAX) 4371 { 4372 _rtld_error("Filename is too long: %s", path); 4373 return(-1); 4374 } 4375 4376 strncpy(bname, path, endp - path + 1); 4377 bname[endp - path + 1] = '\0'; 4378 return (0); 4379 } 4380 4381 static int 4382 rtld_dirname_abs(const char *path, char *base) 4383 { 4384 char *last; 4385 4386 if (realpath(path, base) == NULL) { 4387 _rtld_error("realpath \"%s\" failed (%s)", path, 4388 rtld_strerror(errno)); 4389 return (-1); 4390 } 4391 dbg("%s -> %s", path, base); 4392 last = strrchr(base, '/'); 4393 if (last == NULL) { 4394 _rtld_error("non-abs result from realpath \"%s\"", path); 4395 return (-1); 4396 } 4397 if (last != base) 4398 *last = '\0'; 4399 return (0); 4400 } 4401 4402 static void 4403 linkmap_add(Obj_Entry *obj) 4404 { 4405 struct link_map *l, *prev; 4406 4407 l = &obj->linkmap; 4408 l->l_name = obj->path; 4409 l->l_base = obj->mapbase; 4410 l->l_ld = obj->dynamic; 4411 l->l_addr = obj->relocbase; 4412 4413 if (r_debug.r_map == NULL) { 4414 r_debug.r_map = l; 4415 return; 4416 } 4417 4418 /* 4419 * Scan to the end of the list, but not past the entry for the 4420 * dynamic linker, which we want to keep at the very end. 4421 */ 4422 for (prev = r_debug.r_map; 4423 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4424 prev = prev->l_next) 4425 ; 4426 4427 /* Link in the new entry. */ 4428 l->l_prev = prev; 4429 l->l_next = prev->l_next; 4430 if (l->l_next != NULL) 4431 l->l_next->l_prev = l; 4432 prev->l_next = l; 4433 } 4434 4435 static void 4436 linkmap_delete(Obj_Entry *obj) 4437 { 4438 struct link_map *l; 4439 4440 l = &obj->linkmap; 4441 if (l->l_prev == NULL) { 4442 if ((r_debug.r_map = l->l_next) != NULL) 4443 l->l_next->l_prev = NULL; 4444 return; 4445 } 4446 4447 if ((l->l_prev->l_next = l->l_next) != NULL) 4448 l->l_next->l_prev = l->l_prev; 4449 } 4450 4451 /* 4452 * Function for the debugger to set a breakpoint on to gain control. 4453 * 4454 * The two parameters allow the debugger to easily find and determine 4455 * what the runtime loader is doing and to whom it is doing it. 4456 * 4457 * When the loadhook trap is hit (r_debug_state, set at program 4458 * initialization), the arguments can be found on the stack: 4459 * 4460 * +8 struct link_map *m 4461 * +4 struct r_debug *rd 4462 * +0 RetAddr 4463 */ 4464 void 4465 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4466 { 4467 /* 4468 * The following is a hack to force the compiler to emit calls to 4469 * this function, even when optimizing. If the function is empty, 4470 * the compiler is not obliged to emit any code for calls to it, 4471 * even when marked __noinline. However, gdb depends on those 4472 * calls being made. 4473 */ 4474 __compiler_membar(); 4475 } 4476 4477 /* 4478 * A function called after init routines have completed. This can be used to 4479 * break before a program's entry routine is called, and can be used when 4480 * main is not available in the symbol table. 4481 */ 4482 void 4483 _r_debug_postinit(struct link_map *m __unused) 4484 { 4485 4486 /* See r_debug_state(). */ 4487 __compiler_membar(); 4488 } 4489 4490 static void 4491 release_object(Obj_Entry *obj) 4492 { 4493 4494 if (obj->holdcount > 0) { 4495 obj->unholdfree = true; 4496 return; 4497 } 4498 munmap(obj->mapbase, obj->mapsize); 4499 linkmap_delete(obj); 4500 obj_free(obj); 4501 } 4502 4503 /* 4504 * Get address of the pointer variable in the main program. 4505 * Prefer non-weak symbol over the weak one. 4506 */ 4507 static const void ** 4508 get_program_var_addr(const char *name, RtldLockState *lockstate) 4509 { 4510 SymLook req; 4511 DoneList donelist; 4512 4513 symlook_init(&req, name); 4514 req.lockstate = lockstate; 4515 donelist_init(&donelist); 4516 if (symlook_global(&req, &donelist) != 0) 4517 return (NULL); 4518 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4519 return ((const void **)make_function_pointer(req.sym_out, 4520 req.defobj_out)); 4521 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4522 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4523 else 4524 return ((const void **)(req.defobj_out->relocbase + 4525 req.sym_out->st_value)); 4526 } 4527 4528 /* 4529 * Set a pointer variable in the main program to the given value. This 4530 * is used to set key variables such as "environ" before any of the 4531 * init functions are called. 4532 */ 4533 static void 4534 set_program_var(const char *name, const void *value) 4535 { 4536 const void **addr; 4537 4538 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4539 dbg("\"%s\": *%p <-- %p", name, addr, value); 4540 *addr = value; 4541 } 4542 } 4543 4544 /* 4545 * Search the global objects, including dependencies and main object, 4546 * for the given symbol. 4547 */ 4548 static int 4549 symlook_global(SymLook *req, DoneList *donelist) 4550 { 4551 SymLook req1; 4552 const Objlist_Entry *elm; 4553 int res; 4554 4555 symlook_init_from_req(&req1, req); 4556 4557 /* Search all objects loaded at program start up. */ 4558 if (req->defobj_out == NULL || (ld_dynamic_weak && 4559 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4560 res = symlook_list(&req1, &list_main, donelist); 4561 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4562 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4563 req->sym_out = req1.sym_out; 4564 req->defobj_out = req1.defobj_out; 4565 assert(req->defobj_out != NULL); 4566 } 4567 } 4568 4569 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4570 STAILQ_FOREACH(elm, &list_global, link) { 4571 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4572 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4573 break; 4574 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4575 if (res == 0 && (req->defobj_out == NULL || 4576 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4577 req->sym_out = req1.sym_out; 4578 req->defobj_out = req1.defobj_out; 4579 assert(req->defobj_out != NULL); 4580 } 4581 } 4582 4583 return (req->sym_out != NULL ? 0 : ESRCH); 4584 } 4585 4586 /* 4587 * Given a symbol name in a referencing object, find the corresponding 4588 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4589 * no definition was found. Returns a pointer to the Obj_Entry of the 4590 * defining object via the reference parameter DEFOBJ_OUT. 4591 */ 4592 static int 4593 symlook_default(SymLook *req, const Obj_Entry *refobj) 4594 { 4595 DoneList donelist; 4596 const Objlist_Entry *elm; 4597 SymLook req1; 4598 int res; 4599 4600 donelist_init(&donelist); 4601 symlook_init_from_req(&req1, req); 4602 4603 /* 4604 * Look first in the referencing object if linked symbolically, 4605 * and similarly handle protected symbols. 4606 */ 4607 res = symlook_obj(&req1, refobj); 4608 if (res == 0 && (refobj->symbolic || 4609 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4610 req->sym_out = req1.sym_out; 4611 req->defobj_out = req1.defobj_out; 4612 assert(req->defobj_out != NULL); 4613 } 4614 if (refobj->symbolic || req->defobj_out != NULL) 4615 donelist_check(&donelist, refobj); 4616 4617 if (!refobj->deepbind) 4618 symlook_global(req, &donelist); 4619 4620 /* Search all dlopened DAGs containing the referencing object. */ 4621 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4622 if (req->sym_out != NULL && (!ld_dynamic_weak || 4623 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4624 break; 4625 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4626 if (res == 0 && (req->sym_out == NULL || 4627 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4628 req->sym_out = req1.sym_out; 4629 req->defobj_out = req1.defobj_out; 4630 assert(req->defobj_out != NULL); 4631 } 4632 } 4633 4634 if (refobj->deepbind) 4635 symlook_global(req, &donelist); 4636 4637 /* 4638 * Search the dynamic linker itself, and possibly resolve the 4639 * symbol from there. This is how the application links to 4640 * dynamic linker services such as dlopen. 4641 */ 4642 if (req->sym_out == NULL || 4643 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4644 res = symlook_obj(&req1, &obj_rtld); 4645 if (res == 0) { 4646 req->sym_out = req1.sym_out; 4647 req->defobj_out = req1.defobj_out; 4648 assert(req->defobj_out != NULL); 4649 } 4650 } 4651 4652 return (req->sym_out != NULL ? 0 : ESRCH); 4653 } 4654 4655 static int 4656 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4657 { 4658 const Elf_Sym *def; 4659 const Obj_Entry *defobj; 4660 const Objlist_Entry *elm; 4661 SymLook req1; 4662 int res; 4663 4664 def = NULL; 4665 defobj = NULL; 4666 STAILQ_FOREACH(elm, objlist, link) { 4667 if (donelist_check(dlp, elm->obj)) 4668 continue; 4669 symlook_init_from_req(&req1, req); 4670 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4671 if (def == NULL || (ld_dynamic_weak && 4672 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4673 def = req1.sym_out; 4674 defobj = req1.defobj_out; 4675 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4676 break; 4677 } 4678 } 4679 } 4680 if (def != NULL) { 4681 req->sym_out = def; 4682 req->defobj_out = defobj; 4683 return (0); 4684 } 4685 return (ESRCH); 4686 } 4687 4688 /* 4689 * Search the chain of DAGS cointed to by the given Needed_Entry 4690 * for a symbol of the given name. Each DAG is scanned completely 4691 * before advancing to the next one. Returns a pointer to the symbol, 4692 * or NULL if no definition was found. 4693 */ 4694 static int 4695 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4696 { 4697 const Elf_Sym *def; 4698 const Needed_Entry *n; 4699 const Obj_Entry *defobj; 4700 SymLook req1; 4701 int res; 4702 4703 def = NULL; 4704 defobj = NULL; 4705 symlook_init_from_req(&req1, req); 4706 for (n = needed; n != NULL; n = n->next) { 4707 if (n->obj == NULL || 4708 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4709 continue; 4710 if (def == NULL || (ld_dynamic_weak && 4711 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4712 def = req1.sym_out; 4713 defobj = req1.defobj_out; 4714 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4715 break; 4716 } 4717 } 4718 if (def != NULL) { 4719 req->sym_out = def; 4720 req->defobj_out = defobj; 4721 return (0); 4722 } 4723 return (ESRCH); 4724 } 4725 4726 static int 4727 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, 4728 Needed_Entry *needed) 4729 { 4730 DoneList donelist; 4731 int flags; 4732 4733 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; 4734 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4735 donelist_init(&donelist); 4736 symlook_init_from_req(req1, req); 4737 return (symlook_needed(req1, needed, &donelist)); 4738 } 4739 4740 /* 4741 * Search the symbol table of a single shared object for a symbol of 4742 * the given name and version, if requested. Returns a pointer to the 4743 * symbol, or NULL if no definition was found. If the object is 4744 * filter, return filtered symbol from filtee. 4745 * 4746 * The symbol's hash value is passed in for efficiency reasons; that 4747 * eliminates many recomputations of the hash value. 4748 */ 4749 int 4750 symlook_obj(SymLook *req, const Obj_Entry *obj) 4751 { 4752 SymLook req1; 4753 int res, mres; 4754 4755 /* 4756 * If there is at least one valid hash at this point, we prefer to 4757 * use the faster GNU version if available. 4758 */ 4759 if (obj->valid_hash_gnu) 4760 mres = symlook_obj1_gnu(req, obj); 4761 else if (obj->valid_hash_sysv) 4762 mres = symlook_obj1_sysv(req, obj); 4763 else 4764 return (EINVAL); 4765 4766 if (mres == 0) { 4767 if (obj->needed_filtees != NULL) { 4768 res = symlook_obj_load_filtees(req, &req1, obj, 4769 obj->needed_filtees); 4770 if (res == 0) { 4771 req->sym_out = req1.sym_out; 4772 req->defobj_out = req1.defobj_out; 4773 } 4774 return (res); 4775 } 4776 if (obj->needed_aux_filtees != NULL) { 4777 res = symlook_obj_load_filtees(req, &req1, obj, 4778 obj->needed_aux_filtees); 4779 if (res == 0) { 4780 req->sym_out = req1.sym_out; 4781 req->defobj_out = req1.defobj_out; 4782 return (res); 4783 } 4784 } 4785 } 4786 return (mres); 4787 } 4788 4789 /* Symbol match routine common to both hash functions */ 4790 static bool 4791 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4792 const unsigned long symnum) 4793 { 4794 Elf_Versym verndx; 4795 const Elf_Sym *symp; 4796 const char *strp; 4797 4798 symp = obj->symtab + symnum; 4799 strp = obj->strtab + symp->st_name; 4800 4801 switch (ELF_ST_TYPE(symp->st_info)) { 4802 case STT_FUNC: 4803 case STT_NOTYPE: 4804 case STT_OBJECT: 4805 case STT_COMMON: 4806 case STT_GNU_IFUNC: 4807 if (symp->st_value == 0) 4808 return (false); 4809 /* fallthrough */ 4810 case STT_TLS: 4811 if (symp->st_shndx != SHN_UNDEF) 4812 break; 4813 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4814 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4815 break; 4816 /* fallthrough */ 4817 default: 4818 return (false); 4819 } 4820 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4821 return (false); 4822 4823 if (req->ventry == NULL) { 4824 if (obj->versyms != NULL) { 4825 verndx = VER_NDX(obj->versyms[symnum]); 4826 if (verndx > obj->vernum) { 4827 _rtld_error( 4828 "%s: symbol %s references wrong version %d", 4829 obj->path, obj->strtab + symnum, verndx); 4830 return (false); 4831 } 4832 /* 4833 * If we are not called from dlsym (i.e. this 4834 * is a normal relocation from unversioned 4835 * binary), accept the symbol immediately if 4836 * it happens to have first version after this 4837 * shared object became versioned. Otherwise, 4838 * if symbol is versioned and not hidden, 4839 * remember it. If it is the only symbol with 4840 * this name exported by the shared object, it 4841 * will be returned as a match by the calling 4842 * function. If symbol is global (verndx < 2) 4843 * accept it unconditionally. 4844 */ 4845 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4846 verndx == VER_NDX_GIVEN) { 4847 result->sym_out = symp; 4848 return (true); 4849 } 4850 else if (verndx >= VER_NDX_GIVEN) { 4851 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4852 == 0) { 4853 if (result->vsymp == NULL) 4854 result->vsymp = symp; 4855 result->vcount++; 4856 } 4857 return (false); 4858 } 4859 } 4860 result->sym_out = symp; 4861 return (true); 4862 } 4863 if (obj->versyms == NULL) { 4864 if (object_match_name(obj, req->ventry->name)) { 4865 _rtld_error("%s: object %s should provide version %s " 4866 "for symbol %s", obj_rtld.path, obj->path, 4867 req->ventry->name, obj->strtab + symnum); 4868 return (false); 4869 } 4870 } else { 4871 verndx = VER_NDX(obj->versyms[symnum]); 4872 if (verndx > obj->vernum) { 4873 _rtld_error("%s: symbol %s references wrong version %d", 4874 obj->path, obj->strtab + symnum, verndx); 4875 return (false); 4876 } 4877 if (obj->vertab[verndx].hash != req->ventry->hash || 4878 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4879 /* 4880 * Version does not match. Look if this is a 4881 * global symbol and if it is not hidden. If 4882 * global symbol (verndx < 2) is available, 4883 * use it. Do not return symbol if we are 4884 * called by dlvsym, because dlvsym looks for 4885 * a specific version and default one is not 4886 * what dlvsym wants. 4887 */ 4888 if ((req->flags & SYMLOOK_DLSYM) || 4889 (verndx >= VER_NDX_GIVEN) || 4890 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4891 return (false); 4892 } 4893 } 4894 result->sym_out = symp; 4895 return (true); 4896 } 4897 4898 /* 4899 * Search for symbol using SysV hash function. 4900 * obj->buckets is known not to be NULL at this point; the test for this was 4901 * performed with the obj->valid_hash_sysv assignment. 4902 */ 4903 static int 4904 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4905 { 4906 unsigned long symnum; 4907 Sym_Match_Result matchres; 4908 4909 matchres.sym_out = NULL; 4910 matchres.vsymp = NULL; 4911 matchres.vcount = 0; 4912 4913 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4914 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4915 if (symnum >= obj->nchains) 4916 return (ESRCH); /* Bad object */ 4917 4918 if (matched_symbol(req, obj, &matchres, symnum)) { 4919 req->sym_out = matchres.sym_out; 4920 req->defobj_out = obj; 4921 return (0); 4922 } 4923 } 4924 if (matchres.vcount == 1) { 4925 req->sym_out = matchres.vsymp; 4926 req->defobj_out = obj; 4927 return (0); 4928 } 4929 return (ESRCH); 4930 } 4931 4932 /* Search for symbol using GNU hash function */ 4933 static int 4934 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4935 { 4936 Elf_Addr bloom_word; 4937 const Elf32_Word *hashval; 4938 Elf32_Word bucket; 4939 Sym_Match_Result matchres; 4940 unsigned int h1, h2; 4941 unsigned long symnum; 4942 4943 matchres.sym_out = NULL; 4944 matchres.vsymp = NULL; 4945 matchres.vcount = 0; 4946 4947 /* Pick right bitmask word from Bloom filter array */ 4948 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4949 obj->maskwords_bm_gnu]; 4950 4951 /* Calculate modulus word size of gnu hash and its derivative */ 4952 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4953 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4954 4955 /* Filter out the "definitely not in set" queries */ 4956 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4957 return (ESRCH); 4958 4959 /* Locate hash chain and corresponding value element*/ 4960 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4961 if (bucket == 0) 4962 return (ESRCH); 4963 hashval = &obj->chain_zero_gnu[bucket]; 4964 do { 4965 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4966 symnum = hashval - obj->chain_zero_gnu; 4967 if (matched_symbol(req, obj, &matchres, symnum)) { 4968 req->sym_out = matchres.sym_out; 4969 req->defobj_out = obj; 4970 return (0); 4971 } 4972 } 4973 } while ((*hashval++ & 1) == 0); 4974 if (matchres.vcount == 1) { 4975 req->sym_out = matchres.vsymp; 4976 req->defobj_out = obj; 4977 return (0); 4978 } 4979 return (ESRCH); 4980 } 4981 4982 static void 4983 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4984 { 4985 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4986 if (*main_local == NULL) 4987 *main_local = ""; 4988 4989 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4990 if (*fmt1 == NULL) 4991 *fmt1 = "\t%o => %p (%x)\n"; 4992 4993 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4994 if (*fmt2 == NULL) 4995 *fmt2 = "\t%o (%x)\n"; 4996 } 4997 4998 static void 4999 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 5000 const char *main_local, const char *fmt1, const char *fmt2) 5001 { 5002 const char *fmt; 5003 int c; 5004 5005 if (fmt1 == NULL) 5006 fmt = fmt2; 5007 else 5008 /* XXX bogus */ 5009 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 5010 5011 while ((c = *fmt++) != '\0') { 5012 switch (c) { 5013 default: 5014 rtld_putchar(c); 5015 continue; 5016 case '\\': 5017 switch (c = *fmt) { 5018 case '\0': 5019 continue; 5020 case 'n': 5021 rtld_putchar('\n'); 5022 break; 5023 case 't': 5024 rtld_putchar('\t'); 5025 break; 5026 } 5027 break; 5028 case '%': 5029 switch (c = *fmt) { 5030 case '\0': 5031 continue; 5032 case '%': 5033 default: 5034 rtld_putchar(c); 5035 break; 5036 case 'A': 5037 rtld_putstr(main_local); 5038 break; 5039 case 'a': 5040 rtld_putstr(obj_main->path); 5041 break; 5042 case 'o': 5043 rtld_putstr(name); 5044 break; 5045 case 'p': 5046 rtld_putstr(path); 5047 break; 5048 case 'x': 5049 rtld_printf("%p", obj != NULL ? 5050 obj->mapbase : NULL); 5051 break; 5052 } 5053 break; 5054 } 5055 ++fmt; 5056 } 5057 } 5058 5059 static void 5060 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5061 { 5062 const char *fmt1, *fmt2, *main_local; 5063 const char *name, *path; 5064 bool first_spurious, list_containers; 5065 5066 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5067 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5068 5069 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5070 Needed_Entry *needed; 5071 5072 if (obj->marker) 5073 continue; 5074 if (list_containers && obj->needed != NULL) 5075 rtld_printf("%s:\n", obj->path); 5076 for (needed = obj->needed; needed; needed = needed->next) { 5077 if (needed->obj != NULL) { 5078 if (needed->obj->traced && !list_containers) 5079 continue; 5080 needed->obj->traced = true; 5081 path = needed->obj->path; 5082 } else 5083 path = "not found"; 5084 5085 name = obj->strtab + needed->name; 5086 trace_print_obj(needed->obj, name, path, main_local, 5087 fmt1, fmt2); 5088 } 5089 } 5090 5091 if (show_preload) { 5092 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5093 fmt2 = "\t%p (%x)\n"; 5094 first_spurious = true; 5095 5096 TAILQ_FOREACH(obj, &obj_list, next) { 5097 if (obj->marker || obj == obj_main || obj->traced) 5098 continue; 5099 5100 if (list_containers && first_spurious) { 5101 rtld_printf("[preloaded]\n"); 5102 first_spurious = false; 5103 } 5104 5105 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5106 name = fname == NULL ? "<unknown>" : fname->name; 5107 trace_print_obj(obj, name, obj->path, main_local, 5108 NULL, fmt2); 5109 } 5110 } 5111 } 5112 5113 /* 5114 * Unload a dlopened object and its dependencies from memory and from 5115 * our data structures. It is assumed that the DAG rooted in the 5116 * object has already been unreferenced, and that the object has a 5117 * reference count of 0. 5118 */ 5119 static void 5120 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5121 { 5122 Obj_Entry marker, *obj, *next; 5123 5124 assert(root->refcount == 0); 5125 5126 /* 5127 * Pass over the DAG removing unreferenced objects from 5128 * appropriate lists. 5129 */ 5130 unlink_object(root); 5131 5132 /* Unmap all objects that are no longer referenced. */ 5133 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5134 next = TAILQ_NEXT(obj, next); 5135 if (obj->marker || obj->refcount != 0) 5136 continue; 5137 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5138 obj->mapsize, 0, obj->path); 5139 dbg("unloading \"%s\"", obj->path); 5140 /* 5141 * Unlink the object now to prevent new references from 5142 * being acquired while the bind lock is dropped in 5143 * recursive dlclose() invocations. 5144 */ 5145 TAILQ_REMOVE(&obj_list, obj, next); 5146 obj_count--; 5147 5148 if (obj->filtees_loaded) { 5149 if (next != NULL) { 5150 init_marker(&marker); 5151 TAILQ_INSERT_BEFORE(next, &marker, next); 5152 unload_filtees(obj, lockstate); 5153 next = TAILQ_NEXT(&marker, next); 5154 TAILQ_REMOVE(&obj_list, &marker, next); 5155 } else 5156 unload_filtees(obj, lockstate); 5157 } 5158 release_object(obj); 5159 } 5160 } 5161 5162 static void 5163 unlink_object(Obj_Entry *root) 5164 { 5165 Objlist_Entry *elm; 5166 5167 if (root->refcount == 0) { 5168 /* Remove the object from the RTLD_GLOBAL list. */ 5169 objlist_remove(&list_global, root); 5170 5171 /* Remove the object from all objects' DAG lists. */ 5172 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5173 objlist_remove(&elm->obj->dldags, root); 5174 if (elm->obj != root) 5175 unlink_object(elm->obj); 5176 } 5177 } 5178 } 5179 5180 static void 5181 ref_dag(Obj_Entry *root) 5182 { 5183 Objlist_Entry *elm; 5184 5185 assert(root->dag_inited); 5186 STAILQ_FOREACH(elm, &root->dagmembers, link) 5187 elm->obj->refcount++; 5188 } 5189 5190 static void 5191 unref_dag(Obj_Entry *root) 5192 { 5193 Objlist_Entry *elm; 5194 5195 assert(root->dag_inited); 5196 STAILQ_FOREACH(elm, &root->dagmembers, link) 5197 elm->obj->refcount--; 5198 } 5199 5200 /* 5201 * Common code for MD __tls_get_addr(). 5202 */ 5203 static void * 5204 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5205 { 5206 Elf_Addr *newdtv, *dtv; 5207 RtldLockState lockstate; 5208 int to_copy; 5209 5210 dtv = *dtvp; 5211 /* Check dtv generation in case new modules have arrived */ 5212 if (dtv[0] != tls_dtv_generation) { 5213 if (!locked) 5214 wlock_acquire(rtld_bind_lock, &lockstate); 5215 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5216 to_copy = dtv[1]; 5217 if (to_copy > tls_max_index) 5218 to_copy = tls_max_index; 5219 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5220 newdtv[0] = tls_dtv_generation; 5221 newdtv[1] = tls_max_index; 5222 free(dtv); 5223 if (!locked) 5224 lock_release(rtld_bind_lock, &lockstate); 5225 dtv = *dtvp = newdtv; 5226 } 5227 5228 /* Dynamically allocate module TLS if necessary */ 5229 if (dtv[index + 1] == 0) { 5230 /* Signal safe, wlock will block out signals. */ 5231 if (!locked) 5232 wlock_acquire(rtld_bind_lock, &lockstate); 5233 if (!dtv[index + 1]) 5234 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5235 if (!locked) 5236 lock_release(rtld_bind_lock, &lockstate); 5237 } 5238 return ((void *)(dtv[index + 1] + offset)); 5239 } 5240 5241 void * 5242 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5243 { 5244 uintptr_t *dtv; 5245 5246 dtv = *dtvp; 5247 /* Check dtv generation in case new modules have arrived */ 5248 if (__predict_true(dtv[0] == tls_dtv_generation && 5249 dtv[index + 1] != 0)) 5250 return ((void *)(dtv[index + 1] + offset)); 5251 return (tls_get_addr_slow(dtvp, index, offset, false)); 5252 } 5253 5254 #ifdef TLS_VARIANT_I 5255 5256 /* 5257 * Return pointer to allocated TLS block 5258 */ 5259 static void * 5260 get_tls_block_ptr(void *tcb, size_t tcbsize) 5261 { 5262 size_t extra_size, post_size, pre_size, tls_block_size; 5263 size_t tls_init_align; 5264 5265 tls_init_align = MAX(obj_main->tlsalign, 1); 5266 5267 /* Compute fragments sizes. */ 5268 extra_size = tcbsize - TLS_TCB_SIZE; 5269 post_size = calculate_tls_post_size(tls_init_align); 5270 tls_block_size = tcbsize + post_size; 5271 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5272 5273 return ((char *)tcb - pre_size - extra_size); 5274 } 5275 5276 /* 5277 * Allocate Static TLS using the Variant I method. 5278 * 5279 * For details on the layout, see lib/libc/gen/tls.c. 5280 * 5281 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5282 * it is based on tls_last_offset, and TLS offsets here are really TCB 5283 * offsets, whereas libc's tls_static_space is just the executable's static 5284 * TLS segment. 5285 */ 5286 void * 5287 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5288 { 5289 Obj_Entry *obj; 5290 char *tls_block; 5291 Elf_Addr *dtv, **tcb; 5292 Elf_Addr addr; 5293 Elf_Addr i; 5294 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5295 size_t tls_init_align, tls_init_offset; 5296 5297 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5298 return (oldtcb); 5299 5300 assert(tcbsize >= TLS_TCB_SIZE); 5301 maxalign = MAX(tcbalign, tls_static_max_align); 5302 tls_init_align = MAX(obj_main->tlsalign, 1); 5303 5304 /* Compute fragmets sizes. */ 5305 extra_size = tcbsize - TLS_TCB_SIZE; 5306 post_size = calculate_tls_post_size(tls_init_align); 5307 tls_block_size = tcbsize + post_size; 5308 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5309 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5310 5311 /* Allocate whole TLS block */ 5312 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5313 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5314 5315 if (oldtcb != NULL) { 5316 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5317 tls_static_space); 5318 free(get_tls_block_ptr(oldtcb, tcbsize)); 5319 5320 /* Adjust the DTV. */ 5321 dtv = tcb[0]; 5322 for (i = 0; i < dtv[1]; i++) { 5323 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5324 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5325 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5326 } 5327 } 5328 } else { 5329 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5330 tcb[0] = dtv; 5331 dtv[0] = tls_dtv_generation; 5332 dtv[1] = tls_max_index; 5333 5334 for (obj = globallist_curr(objs); obj != NULL; 5335 obj = globallist_next(obj)) { 5336 if (obj->tlsoffset == 0) 5337 continue; 5338 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5339 addr = (Elf_Addr)tcb + obj->tlsoffset; 5340 if (tls_init_offset > 0) 5341 memset((void *)addr, 0, tls_init_offset); 5342 if (obj->tlsinitsize > 0) { 5343 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5344 obj->tlsinitsize); 5345 } 5346 if (obj->tlssize > obj->tlsinitsize) { 5347 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5348 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5349 } 5350 dtv[obj->tlsindex + 1] = addr; 5351 } 5352 } 5353 5354 return (tcb); 5355 } 5356 5357 void 5358 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5359 { 5360 Elf_Addr *dtv; 5361 Elf_Addr tlsstart, tlsend; 5362 size_t post_size; 5363 size_t dtvsize, i, tls_init_align __unused; 5364 5365 assert(tcbsize >= TLS_TCB_SIZE); 5366 tls_init_align = MAX(obj_main->tlsalign, 1); 5367 5368 /* Compute fragments sizes. */ 5369 post_size = calculate_tls_post_size(tls_init_align); 5370 5371 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5372 tlsend = (Elf_Addr)tcb + tls_static_space; 5373 5374 dtv = *(Elf_Addr **)tcb; 5375 dtvsize = dtv[1]; 5376 for (i = 0; i < dtvsize; i++) { 5377 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5378 free((void*)dtv[i+2]); 5379 } 5380 } 5381 free(dtv); 5382 free(get_tls_block_ptr(tcb, tcbsize)); 5383 } 5384 5385 #endif /* TLS_VARIANT_I */ 5386 5387 #ifdef TLS_VARIANT_II 5388 5389 /* 5390 * Allocate Static TLS using the Variant II method. 5391 */ 5392 void * 5393 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5394 { 5395 Obj_Entry *obj; 5396 size_t size, ralign; 5397 char *tls; 5398 Elf_Addr *dtv, *olddtv; 5399 Elf_Addr segbase, oldsegbase, addr; 5400 size_t i; 5401 5402 ralign = tcbalign; 5403 if (tls_static_max_align > ralign) 5404 ralign = tls_static_max_align; 5405 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5406 5407 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5408 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5409 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5410 5411 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5412 ((Elf_Addr *)segbase)[0] = segbase; 5413 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5414 5415 dtv[0] = tls_dtv_generation; 5416 dtv[1] = tls_max_index; 5417 5418 if (oldtls) { 5419 /* 5420 * Copy the static TLS block over whole. 5421 */ 5422 oldsegbase = (Elf_Addr) oldtls; 5423 memcpy((void *)(segbase - tls_static_space), 5424 (const void *)(oldsegbase - tls_static_space), 5425 tls_static_space); 5426 5427 /* 5428 * If any dynamic TLS blocks have been created tls_get_addr(), 5429 * move them over. 5430 */ 5431 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5432 for (i = 0; i < olddtv[1]; i++) { 5433 if (olddtv[i + 2] < oldsegbase - size || 5434 olddtv[i + 2] > oldsegbase) { 5435 dtv[i + 2] = olddtv[i + 2]; 5436 olddtv[i + 2] = 0; 5437 } 5438 } 5439 5440 /* 5441 * We assume that this block was the one we created with 5442 * allocate_initial_tls(). 5443 */ 5444 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5445 } else { 5446 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5447 if (obj->marker || obj->tlsoffset == 0) 5448 continue; 5449 addr = segbase - obj->tlsoffset; 5450 memset((void *)(addr + obj->tlsinitsize), 5451 0, obj->tlssize - obj->tlsinitsize); 5452 if (obj->tlsinit) { 5453 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5454 obj->static_tls_copied = true; 5455 } 5456 dtv[obj->tlsindex + 1] = addr; 5457 } 5458 } 5459 5460 return ((void *)segbase); 5461 } 5462 5463 void 5464 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5465 { 5466 Elf_Addr* dtv; 5467 size_t size, ralign; 5468 int dtvsize, i; 5469 Elf_Addr tlsstart, tlsend; 5470 5471 /* 5472 * Figure out the size of the initial TLS block so that we can 5473 * find stuff which ___tls_get_addr() allocated dynamically. 5474 */ 5475 ralign = tcbalign; 5476 if (tls_static_max_align > ralign) 5477 ralign = tls_static_max_align; 5478 size = roundup(tls_static_space, ralign); 5479 5480 dtv = ((Elf_Addr **)tls)[1]; 5481 dtvsize = dtv[1]; 5482 tlsend = (Elf_Addr)tls; 5483 tlsstart = tlsend - size; 5484 for (i = 0; i < dtvsize; i++) { 5485 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5486 dtv[i + 2] > tlsend)) { 5487 free((void *)dtv[i + 2]); 5488 } 5489 } 5490 5491 free((void *)tlsstart); 5492 free((void *)dtv); 5493 } 5494 5495 #endif /* TLS_VARIANT_II */ 5496 5497 /* 5498 * Allocate TLS block for module with given index. 5499 */ 5500 void * 5501 allocate_module_tls(int index) 5502 { 5503 Obj_Entry *obj; 5504 char *p; 5505 5506 TAILQ_FOREACH(obj, &obj_list, next) { 5507 if (obj->marker) 5508 continue; 5509 if (obj->tlsindex == index) 5510 break; 5511 } 5512 if (obj == NULL) { 5513 _rtld_error("Can't find module with TLS index %d", index); 5514 rtld_die(); 5515 } 5516 5517 if (obj->tls_static) { 5518 #ifdef TLS_VARIANT_I 5519 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5520 #else 5521 p = (char *)_tcb_get() - obj->tlsoffset; 5522 #endif 5523 return (p); 5524 } 5525 5526 obj->tls_dynamic = true; 5527 5528 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5529 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5530 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5531 return (p); 5532 } 5533 5534 bool 5535 allocate_tls_offset(Obj_Entry *obj) 5536 { 5537 size_t off; 5538 5539 if (obj->tls_dynamic) 5540 return (false); 5541 5542 if (obj->tls_static) 5543 return (true); 5544 5545 if (obj->tlssize == 0) { 5546 obj->tls_static = true; 5547 return (true); 5548 } 5549 5550 if (tls_last_offset == 0) 5551 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5552 obj->tlspoffset); 5553 else 5554 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5555 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5556 5557 obj->tlsoffset = off; 5558 #ifdef TLS_VARIANT_I 5559 off += obj->tlssize; 5560 #endif 5561 5562 /* 5563 * If we have already fixed the size of the static TLS block, we 5564 * must stay within that size. When allocating the static TLS, we 5565 * leave a small amount of space spare to be used for dynamically 5566 * loading modules which use static TLS. 5567 */ 5568 if (tls_static_space != 0) { 5569 if (off > tls_static_space) 5570 return (false); 5571 } else if (obj->tlsalign > tls_static_max_align) { 5572 tls_static_max_align = obj->tlsalign; 5573 } 5574 5575 tls_last_offset = off; 5576 tls_last_size = obj->tlssize; 5577 obj->tls_static = true; 5578 5579 return (true); 5580 } 5581 5582 void 5583 free_tls_offset(Obj_Entry *obj) 5584 { 5585 5586 /* 5587 * If we were the last thing to allocate out of the static TLS 5588 * block, we give our space back to the 'allocator'. This is a 5589 * simplistic workaround to allow libGL.so.1 to be loaded and 5590 * unloaded multiple times. 5591 */ 5592 size_t off = obj->tlsoffset; 5593 #ifdef TLS_VARIANT_I 5594 off += obj->tlssize; 5595 #endif 5596 if (off == tls_last_offset) { 5597 tls_last_offset -= obj->tlssize; 5598 tls_last_size = 0; 5599 } 5600 } 5601 5602 void * 5603 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5604 { 5605 void *ret; 5606 RtldLockState lockstate; 5607 5608 wlock_acquire(rtld_bind_lock, &lockstate); 5609 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5610 tcbsize, tcbalign); 5611 lock_release(rtld_bind_lock, &lockstate); 5612 return (ret); 5613 } 5614 5615 void 5616 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5617 { 5618 RtldLockState lockstate; 5619 5620 wlock_acquire(rtld_bind_lock, &lockstate); 5621 free_tls(tcb, tcbsize, tcbalign); 5622 lock_release(rtld_bind_lock, &lockstate); 5623 } 5624 5625 static void 5626 object_add_name(Obj_Entry *obj, const char *name) 5627 { 5628 Name_Entry *entry; 5629 size_t len; 5630 5631 len = strlen(name); 5632 entry = malloc(sizeof(Name_Entry) + len); 5633 5634 if (entry != NULL) { 5635 strcpy(entry->name, name); 5636 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5637 } 5638 } 5639 5640 static int 5641 object_match_name(const Obj_Entry *obj, const char *name) 5642 { 5643 Name_Entry *entry; 5644 5645 STAILQ_FOREACH(entry, &obj->names, link) { 5646 if (strcmp(name, entry->name) == 0) 5647 return (1); 5648 } 5649 return (0); 5650 } 5651 5652 static Obj_Entry * 5653 locate_dependency(const Obj_Entry *obj, const char *name) 5654 { 5655 const Objlist_Entry *entry; 5656 const Needed_Entry *needed; 5657 5658 STAILQ_FOREACH(entry, &list_main, link) { 5659 if (object_match_name(entry->obj, name)) 5660 return (entry->obj); 5661 } 5662 5663 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5664 if (strcmp(obj->strtab + needed->name, name) == 0 || 5665 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5666 /* 5667 * If there is DT_NEEDED for the name we are looking for, 5668 * we are all set. Note that object might not be found if 5669 * dependency was not loaded yet, so the function can 5670 * return NULL here. This is expected and handled 5671 * properly by the caller. 5672 */ 5673 return (needed->obj); 5674 } 5675 } 5676 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5677 obj->path, name); 5678 rtld_die(); 5679 } 5680 5681 static int 5682 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5683 const Elf_Vernaux *vna) 5684 { 5685 const Elf_Verdef *vd; 5686 const char *vername; 5687 5688 vername = refobj->strtab + vna->vna_name; 5689 vd = depobj->verdef; 5690 if (vd == NULL) { 5691 _rtld_error("%s: version %s required by %s not defined", 5692 depobj->path, vername, refobj->path); 5693 return (-1); 5694 } 5695 for (;;) { 5696 if (vd->vd_version != VER_DEF_CURRENT) { 5697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5698 depobj->path, vd->vd_version); 5699 return (-1); 5700 } 5701 if (vna->vna_hash == vd->vd_hash) { 5702 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5703 ((const char *)vd + vd->vd_aux); 5704 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5705 return (0); 5706 } 5707 if (vd->vd_next == 0) 5708 break; 5709 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5710 } 5711 if (vna->vna_flags & VER_FLG_WEAK) 5712 return (0); 5713 _rtld_error("%s: version %s required by %s not found", 5714 depobj->path, vername, refobj->path); 5715 return (-1); 5716 } 5717 5718 static int 5719 rtld_verify_object_versions(Obj_Entry *obj) 5720 { 5721 const Elf_Verneed *vn; 5722 const Elf_Verdef *vd; 5723 const Elf_Verdaux *vda; 5724 const Elf_Vernaux *vna; 5725 const Obj_Entry *depobj; 5726 int maxvernum, vernum; 5727 5728 if (obj->ver_checked) 5729 return (0); 5730 obj->ver_checked = true; 5731 5732 maxvernum = 0; 5733 /* 5734 * Walk over defined and required version records and figure out 5735 * max index used by any of them. Do very basic sanity checking 5736 * while there. 5737 */ 5738 vn = obj->verneed; 5739 while (vn != NULL) { 5740 if (vn->vn_version != VER_NEED_CURRENT) { 5741 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5742 obj->path, vn->vn_version); 5743 return (-1); 5744 } 5745 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5746 for (;;) { 5747 vernum = VER_NEED_IDX(vna->vna_other); 5748 if (vernum > maxvernum) 5749 maxvernum = vernum; 5750 if (vna->vna_next == 0) 5751 break; 5752 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5753 } 5754 if (vn->vn_next == 0) 5755 break; 5756 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5757 } 5758 5759 vd = obj->verdef; 5760 while (vd != NULL) { 5761 if (vd->vd_version != VER_DEF_CURRENT) { 5762 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5763 obj->path, vd->vd_version); 5764 return (-1); 5765 } 5766 vernum = VER_DEF_IDX(vd->vd_ndx); 5767 if (vernum > maxvernum) 5768 maxvernum = vernum; 5769 if (vd->vd_next == 0) 5770 break; 5771 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5772 } 5773 5774 if (maxvernum == 0) 5775 return (0); 5776 5777 /* 5778 * Store version information in array indexable by version index. 5779 * Verify that object version requirements are satisfied along the 5780 * way. 5781 */ 5782 obj->vernum = maxvernum + 1; 5783 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5784 5785 vd = obj->verdef; 5786 while (vd != NULL) { 5787 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5788 vernum = VER_DEF_IDX(vd->vd_ndx); 5789 assert(vernum <= maxvernum); 5790 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5791 obj->vertab[vernum].hash = vd->vd_hash; 5792 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5793 obj->vertab[vernum].file = NULL; 5794 obj->vertab[vernum].flags = 0; 5795 } 5796 if (vd->vd_next == 0) 5797 break; 5798 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5799 } 5800 5801 vn = obj->verneed; 5802 while (vn != NULL) { 5803 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5804 if (depobj == NULL) 5805 return (-1); 5806 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5807 for (;;) { 5808 if (check_object_provided_version(obj, depobj, vna)) 5809 return (-1); 5810 vernum = VER_NEED_IDX(vna->vna_other); 5811 assert(vernum <= maxvernum); 5812 obj->vertab[vernum].hash = vna->vna_hash; 5813 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5814 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5815 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5816 VER_INFO_HIDDEN : 0; 5817 if (vna->vna_next == 0) 5818 break; 5819 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5820 } 5821 if (vn->vn_next == 0) 5822 break; 5823 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5824 } 5825 return (0); 5826 } 5827 5828 static int 5829 rtld_verify_versions(const Objlist *objlist) 5830 { 5831 Objlist_Entry *entry; 5832 int rc; 5833 5834 rc = 0; 5835 STAILQ_FOREACH(entry, objlist, link) { 5836 /* 5837 * Skip dummy objects or objects that have their version requirements 5838 * already checked. 5839 */ 5840 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5841 continue; 5842 if (rtld_verify_object_versions(entry->obj) == -1) { 5843 rc = -1; 5844 if (ld_tracing == NULL) 5845 break; 5846 } 5847 } 5848 if (rc == 0 || ld_tracing != NULL) 5849 rc = rtld_verify_object_versions(&obj_rtld); 5850 return (rc); 5851 } 5852 5853 const Ver_Entry * 5854 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5855 { 5856 Elf_Versym vernum; 5857 5858 if (obj->vertab) { 5859 vernum = VER_NDX(obj->versyms[symnum]); 5860 if (vernum >= obj->vernum) { 5861 _rtld_error("%s: symbol %s has wrong verneed value %d", 5862 obj->path, obj->strtab + symnum, vernum); 5863 } else if (obj->vertab[vernum].hash != 0) { 5864 return (&obj->vertab[vernum]); 5865 } 5866 } 5867 return (NULL); 5868 } 5869 5870 int 5871 _rtld_get_stack_prot(void) 5872 { 5873 5874 return (stack_prot); 5875 } 5876 5877 int 5878 _rtld_is_dlopened(void *arg) 5879 { 5880 Obj_Entry *obj; 5881 RtldLockState lockstate; 5882 int res; 5883 5884 rlock_acquire(rtld_bind_lock, &lockstate); 5885 obj = dlcheck(arg); 5886 if (obj == NULL) 5887 obj = obj_from_addr(arg); 5888 if (obj == NULL) { 5889 _rtld_error("No shared object contains address"); 5890 lock_release(rtld_bind_lock, &lockstate); 5891 return (-1); 5892 } 5893 res = obj->dlopened ? 1 : 0; 5894 lock_release(rtld_bind_lock, &lockstate); 5895 return (res); 5896 } 5897 5898 static int 5899 obj_remap_relro(Obj_Entry *obj, int prot) 5900 { 5901 const Elf_Phdr *ph; 5902 caddr_t relro_page; 5903 size_t relro_size; 5904 5905 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 5906 obj->phsize; ph++) { 5907 switch (ph->p_type) { 5908 case PT_GNU_RELRO: 5909 relro_page = obj->relocbase + 5910 rtld_trunc_page(ph->p_vaddr); 5911 relro_size = 5912 rtld_round_page(ph->p_vaddr + ph->p_memsz) - 5913 rtld_trunc_page(ph->p_vaddr); 5914 if (mprotect(relro_page, relro_size, prot) == -1) { 5915 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5916 obj->path, prot, rtld_strerror(errno)); 5917 return (-1); 5918 } 5919 break; 5920 } 5921 } 5922 return (0); 5923 } 5924 5925 static int 5926 obj_disable_relro(Obj_Entry *obj) 5927 { 5928 5929 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5930 } 5931 5932 static int 5933 obj_enforce_relro(Obj_Entry *obj) 5934 { 5935 5936 return (obj_remap_relro(obj, PROT_READ)); 5937 } 5938 5939 static void 5940 map_stacks_exec(RtldLockState *lockstate) 5941 { 5942 void (*thr_map_stacks_exec)(void); 5943 5944 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5945 return; 5946 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5947 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5948 if (thr_map_stacks_exec != NULL) { 5949 stack_prot |= PROT_EXEC; 5950 thr_map_stacks_exec(); 5951 } 5952 } 5953 5954 static void 5955 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5956 { 5957 Objlist_Entry *elm; 5958 Obj_Entry *obj; 5959 void (*distrib)(size_t, void *, size_t, size_t); 5960 5961 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5962 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5963 if (distrib == NULL) 5964 return; 5965 STAILQ_FOREACH(elm, list, link) { 5966 obj = elm->obj; 5967 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5968 continue; 5969 lock_release(rtld_bind_lock, lockstate); 5970 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5971 obj->tlssize); 5972 wlock_acquire(rtld_bind_lock, lockstate); 5973 obj->static_tls_copied = true; 5974 } 5975 } 5976 5977 void 5978 symlook_init(SymLook *dst, const char *name) 5979 { 5980 5981 bzero(dst, sizeof(*dst)); 5982 dst->name = name; 5983 dst->hash = elf_hash(name); 5984 dst->hash_gnu = gnu_hash(name); 5985 } 5986 5987 static void 5988 symlook_init_from_req(SymLook *dst, const SymLook *src) 5989 { 5990 5991 dst->name = src->name; 5992 dst->hash = src->hash; 5993 dst->hash_gnu = src->hash_gnu; 5994 dst->ventry = src->ventry; 5995 dst->flags = src->flags; 5996 dst->defobj_out = NULL; 5997 dst->sym_out = NULL; 5998 dst->lockstate = src->lockstate; 5999 } 6000 6001 static int 6002 open_binary_fd(const char *argv0, bool search_in_path, 6003 const char **binpath_res) 6004 { 6005 char *binpath, *pathenv, *pe, *res1; 6006 const char *res; 6007 int fd; 6008 6009 binpath = NULL; 6010 res = NULL; 6011 if (search_in_path && strchr(argv0, '/') == NULL) { 6012 binpath = xmalloc(PATH_MAX); 6013 pathenv = getenv("PATH"); 6014 if (pathenv == NULL) { 6015 _rtld_error("-p and no PATH environment variable"); 6016 rtld_die(); 6017 } 6018 pathenv = strdup(pathenv); 6019 if (pathenv == NULL) { 6020 _rtld_error("Cannot allocate memory"); 6021 rtld_die(); 6022 } 6023 fd = -1; 6024 errno = ENOENT; 6025 while ((pe = strsep(&pathenv, ":")) != NULL) { 6026 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 6027 continue; 6028 if (binpath[0] != '\0' && 6029 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 6030 continue; 6031 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 6032 continue; 6033 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 6034 if (fd != -1 || errno != ENOENT) { 6035 res = binpath; 6036 break; 6037 } 6038 } 6039 free(pathenv); 6040 } else { 6041 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 6042 res = argv0; 6043 } 6044 6045 if (fd == -1) { 6046 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 6047 rtld_die(); 6048 } 6049 if (res != NULL && res[0] != '/') { 6050 res1 = xmalloc(PATH_MAX); 6051 if (realpath(res, res1) != NULL) { 6052 if (res != argv0) 6053 free(__DECONST(char *, res)); 6054 res = res1; 6055 } else { 6056 free(res1); 6057 } 6058 } 6059 *binpath_res = res; 6060 return (fd); 6061 } 6062 6063 /* 6064 * Parse a set of command-line arguments. 6065 */ 6066 static int 6067 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6068 const char **argv0, bool *dir_ignore) 6069 { 6070 const char *arg; 6071 char machine[64]; 6072 size_t sz; 6073 int arglen, fd, i, j, mib[2]; 6074 char opt; 6075 bool seen_b, seen_f; 6076 6077 dbg("Parsing command-line arguments"); 6078 *use_pathp = false; 6079 *fdp = -1; 6080 *dir_ignore = false; 6081 seen_b = seen_f = false; 6082 6083 for (i = 1; i < argc; i++ ) { 6084 arg = argv[i]; 6085 dbg("argv[%d]: '%s'", i, arg); 6086 6087 /* 6088 * rtld arguments end with an explicit "--" or with the first 6089 * non-prefixed argument. 6090 */ 6091 if (strcmp(arg, "--") == 0) { 6092 i++; 6093 break; 6094 } 6095 if (arg[0] != '-') 6096 break; 6097 6098 /* 6099 * All other arguments are single-character options that can 6100 * be combined, so we need to search through `arg` for them. 6101 */ 6102 arglen = strlen(arg); 6103 for (j = 1; j < arglen; j++) { 6104 opt = arg[j]; 6105 if (opt == 'h') { 6106 print_usage(argv[0]); 6107 _exit(0); 6108 } else if (opt == 'b') { 6109 if (seen_f) { 6110 _rtld_error("Both -b and -f specified"); 6111 rtld_die(); 6112 } 6113 if (j != arglen - 1) { 6114 _rtld_error("Invalid options: %s", arg); 6115 rtld_die(); 6116 } 6117 i++; 6118 *argv0 = argv[i]; 6119 seen_b = true; 6120 break; 6121 } else if (opt == 'd') { 6122 *dir_ignore = true; 6123 } else if (opt == 'f') { 6124 if (seen_b) { 6125 _rtld_error("Both -b and -f specified"); 6126 rtld_die(); 6127 } 6128 6129 /* 6130 * -f XX can be used to specify a 6131 * descriptor for the binary named at 6132 * the command line (i.e., the later 6133 * argument will specify the process 6134 * name but the descriptor is what 6135 * will actually be executed). 6136 * 6137 * -f must be the last option in the 6138 * group, e.g., -abcf <fd>. 6139 */ 6140 if (j != arglen - 1) { 6141 _rtld_error("Invalid options: %s", arg); 6142 rtld_die(); 6143 } 6144 i++; 6145 fd = parse_integer(argv[i]); 6146 if (fd == -1) { 6147 _rtld_error( 6148 "Invalid file descriptor: '%s'", 6149 argv[i]); 6150 rtld_die(); 6151 } 6152 *fdp = fd; 6153 seen_f = true; 6154 break; 6155 } else if (opt == 'o') { 6156 struct ld_env_var_desc *l; 6157 char *n, *v; 6158 u_int ll; 6159 6160 if (j != arglen - 1) { 6161 _rtld_error("Invalid options: %s", arg); 6162 rtld_die(); 6163 } 6164 i++; 6165 n = argv[i]; 6166 v = strchr(n, '='); 6167 if (v == NULL) { 6168 _rtld_error("No '=' in -o parameter"); 6169 rtld_die(); 6170 } 6171 for (ll = 0; ll < nitems(ld_env_vars); ll++) { 6172 l = &ld_env_vars[ll]; 6173 if (v - n == (ptrdiff_t)strlen(l->n) && 6174 strncmp(n, l->n, v - n) == 0) { 6175 l->val = v + 1; 6176 break; 6177 } 6178 } 6179 if (ll == nitems(ld_env_vars)) { 6180 _rtld_error("Unknown LD_ option %s", 6181 n); 6182 rtld_die(); 6183 } 6184 } else if (opt == 'p') { 6185 *use_pathp = true; 6186 } else if (opt == 'u') { 6187 u_int ll; 6188 6189 for (ll = 0; ll < nitems(ld_env_vars); ll++) 6190 ld_env_vars[ll].val = NULL; 6191 } else if (opt == 'v') { 6192 machine[0] = '\0'; 6193 mib[0] = CTL_HW; 6194 mib[1] = HW_MACHINE; 6195 sz = sizeof(machine); 6196 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6197 ld_elf_hints_path = ld_get_env_var( 6198 LD_ELF_HINTS_PATH); 6199 set_ld_elf_hints_path(); 6200 rtld_printf( 6201 "FreeBSD ld-elf.so.1 %s\n" 6202 "FreeBSD_version %d\n" 6203 "Default lib path %s\n" 6204 "Hints lib path %s\n" 6205 "Env prefix %s\n" 6206 "Default hint file %s\n" 6207 "Hint file %s\n" 6208 "libmap file %s\n" 6209 "Optional static TLS size %zd bytes\n", 6210 machine, 6211 __FreeBSD_version, ld_standard_library_path, 6212 gethints(false), 6213 ld_env_prefix, ld_elf_hints_default, 6214 ld_elf_hints_path, 6215 ld_path_libmap_conf, 6216 ld_static_tls_extra); 6217 _exit(0); 6218 } else { 6219 _rtld_error("Invalid argument: '%s'", arg); 6220 print_usage(argv[0]); 6221 rtld_die(); 6222 } 6223 } 6224 } 6225 6226 if (!seen_b) 6227 *argv0 = argv[i]; 6228 return (i); 6229 } 6230 6231 /* 6232 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6233 */ 6234 static int 6235 parse_integer(const char *str) 6236 { 6237 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6238 const char *orig; 6239 int n; 6240 char c; 6241 6242 orig = str; 6243 n = 0; 6244 for (c = *str; c != '\0'; c = *++str) { 6245 if (c < '0' || c > '9') 6246 return (-1); 6247 6248 n *= RADIX; 6249 n += c - '0'; 6250 } 6251 6252 /* Make sure we actually parsed something. */ 6253 if (str == orig) 6254 return (-1); 6255 return (n); 6256 } 6257 6258 static void 6259 print_usage(const char *argv0) 6260 { 6261 6262 rtld_printf( 6263 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6264 "\n" 6265 "Options:\n" 6266 " -h Display this help message\n" 6267 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6268 " -d Ignore lack of exec permissions for the binary\n" 6269 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6270 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n" 6271 " -p Search in PATH for named binary\n" 6272 " -u Ignore LD_ environment variables\n" 6273 " -v Display identification information\n" 6274 " -- End of RTLD options\n" 6275 " <binary> Name of process to execute\n" 6276 " <args> Arguments to the executed process\n", argv0); 6277 } 6278 6279 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6280 static const struct auxfmt { 6281 const char *name; 6282 const char *fmt; 6283 } auxfmts[] = { 6284 AUXFMT(AT_NULL, NULL), 6285 AUXFMT(AT_IGNORE, NULL), 6286 AUXFMT(AT_EXECFD, "%ld"), 6287 AUXFMT(AT_PHDR, "%p"), 6288 AUXFMT(AT_PHENT, "%lu"), 6289 AUXFMT(AT_PHNUM, "%lu"), 6290 AUXFMT(AT_PAGESZ, "%lu"), 6291 AUXFMT(AT_BASE, "%#lx"), 6292 AUXFMT(AT_FLAGS, "%#lx"), 6293 AUXFMT(AT_ENTRY, "%p"), 6294 AUXFMT(AT_NOTELF, NULL), 6295 AUXFMT(AT_UID, "%ld"), 6296 AUXFMT(AT_EUID, "%ld"), 6297 AUXFMT(AT_GID, "%ld"), 6298 AUXFMT(AT_EGID, "%ld"), 6299 AUXFMT(AT_EXECPATH, "%s"), 6300 AUXFMT(AT_CANARY, "%p"), 6301 AUXFMT(AT_CANARYLEN, "%lu"), 6302 AUXFMT(AT_OSRELDATE, "%lu"), 6303 AUXFMT(AT_NCPUS, "%lu"), 6304 AUXFMT(AT_PAGESIZES, "%p"), 6305 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6306 AUXFMT(AT_TIMEKEEP, "%p"), 6307 AUXFMT(AT_STACKPROT, "%#lx"), 6308 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6309 AUXFMT(AT_HWCAP, "%#lx"), 6310 AUXFMT(AT_HWCAP2, "%#lx"), 6311 AUXFMT(AT_BSDFLAGS, "%#lx"), 6312 AUXFMT(AT_ARGC, "%lu"), 6313 AUXFMT(AT_ARGV, "%p"), 6314 AUXFMT(AT_ENVC, "%p"), 6315 AUXFMT(AT_ENVV, "%p"), 6316 AUXFMT(AT_PS_STRINGS, "%p"), 6317 AUXFMT(AT_FXRNG, "%p"), 6318 AUXFMT(AT_KPRELOAD, "%p"), 6319 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6320 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6321 }; 6322 6323 static bool 6324 is_ptr_fmt(const char *fmt) 6325 { 6326 char last; 6327 6328 last = fmt[strlen(fmt) - 1]; 6329 return (last == 'p' || last == 's'); 6330 } 6331 6332 static void 6333 dump_auxv(Elf_Auxinfo **aux_info) 6334 { 6335 Elf_Auxinfo *auxp; 6336 const struct auxfmt *fmt; 6337 int i; 6338 6339 for (i = 0; i < AT_COUNT; i++) { 6340 auxp = aux_info[i]; 6341 if (auxp == NULL) 6342 continue; 6343 fmt = &auxfmts[i]; 6344 if (fmt->fmt == NULL) 6345 continue; 6346 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6347 if (is_ptr_fmt(fmt->fmt)) { 6348 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6349 auxp->a_un.a_ptr); 6350 } else { 6351 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6352 auxp->a_un.a_val); 6353 } 6354 rtld_fdprintf(STDOUT_FILENO, "\n"); 6355 } 6356 } 6357 6358 const char * 6359 rtld_get_var(const char *name) 6360 { 6361 const struct ld_env_var_desc *lvd; 6362 u_int i; 6363 6364 for (i = 0; i < nitems(ld_env_vars); i++) { 6365 lvd = &ld_env_vars[i]; 6366 if (strcmp(lvd->n, name) == 0) 6367 return (lvd->val); 6368 } 6369 return (NULL); 6370 } 6371 6372 int 6373 rtld_set_var(const char *name, const char *val) 6374 { 6375 struct ld_env_var_desc *lvd; 6376 u_int i; 6377 6378 for (i = 0; i < nitems(ld_env_vars); i++) { 6379 lvd = &ld_env_vars[i]; 6380 if (strcmp(lvd->n, name) != 0) 6381 continue; 6382 if (!lvd->can_update || (lvd->unsecure && !trust)) 6383 return (EPERM); 6384 if (lvd->owned) 6385 free(__DECONST(char *, lvd->val)); 6386 if (val != NULL) 6387 lvd->val = xstrdup(val); 6388 else 6389 lvd->val = NULL; 6390 lvd->owned = true; 6391 if (lvd->debug) 6392 debug = lvd->val != NULL && *lvd->val != '\0'; 6393 return (0); 6394 } 6395 return (ENOENT); 6396 } 6397 6398 /* 6399 * Overrides for libc_pic-provided functions. 6400 */ 6401 6402 int 6403 __getosreldate(void) 6404 { 6405 size_t len; 6406 int oid[2]; 6407 int error, osrel; 6408 6409 if (osreldate != 0) 6410 return (osreldate); 6411 6412 oid[0] = CTL_KERN; 6413 oid[1] = KERN_OSRELDATE; 6414 osrel = 0; 6415 len = sizeof(osrel); 6416 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6417 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6418 osreldate = osrel; 6419 return (osreldate); 6420 } 6421 const char * 6422 rtld_strerror(int errnum) 6423 { 6424 6425 if (errnum < 0 || errnum >= sys_nerr) 6426 return ("Unknown error"); 6427 return (sys_errlist[errnum]); 6428 } 6429 6430 char * 6431 getenv(const char *name) 6432 { 6433 return (__DECONST(char *, rtld_get_env_val(environ, name, 6434 strlen(name)))); 6435 } 6436 6437 /* malloc */ 6438 void * 6439 malloc(size_t nbytes) 6440 { 6441 6442 return (__crt_malloc(nbytes)); 6443 } 6444 6445 void * 6446 calloc(size_t num, size_t size) 6447 { 6448 6449 return (__crt_calloc(num, size)); 6450 } 6451 6452 void 6453 free(void *cp) 6454 { 6455 6456 __crt_free(cp); 6457 } 6458 6459 void * 6460 realloc(void *cp, size_t nbytes) 6461 { 6462 6463 return (__crt_realloc(cp, nbytes)); 6464 } 6465 6466 extern int _rtld_version__FreeBSD_version __exported; 6467 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6468 6469 extern char _rtld_version_laddr_offset __exported; 6470 char _rtld_version_laddr_offset; 6471 6472 extern char _rtld_version_dlpi_tls_data __exported; 6473 char _rtld_version_dlpi_tls_data; 6474