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