1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "rtld_paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 struct dlerror_save { 85 int seen; 86 char *msg; 87 }; 88 89 /* 90 * Function declarations. 91 */ 92 static const char *basename(const char *); 93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 94 const Elf_Dyn **, const Elf_Dyn **); 95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 96 const Elf_Dyn *); 97 static bool digest_dynamic(Obj_Entry *, int); 98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 99 static void distribute_static_tls(Objlist *, RtldLockState *); 100 static Obj_Entry *dlcheck(void *); 101 static int dlclose_locked(void *, RtldLockState *); 102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 103 int lo_flags, int mode, RtldLockState *lockstate); 104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 106 static bool donelist_check(DoneList *, const Obj_Entry *); 107 static void dump_auxv(Elf_Auxinfo **aux_info); 108 static void errmsg_restore(struct dlerror_save *); 109 static struct dlerror_save *errmsg_save(void); 110 static void *fill_search_info(const char *, size_t, void *); 111 static char *find_library(const char *, const Obj_Entry *, int *); 112 static const char *gethints(bool); 113 static void hold_object(Obj_Entry *); 114 static void unhold_object(Obj_Entry *); 115 static void init_dag(Obj_Entry *); 116 static void init_marker(Obj_Entry *); 117 static void init_pagesizes(Elf_Auxinfo **aux_info); 118 static void init_rtld(caddr_t, Elf_Auxinfo **); 119 static void initlist_add_neededs(Needed_Entry *, Objlist *); 120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 122 static void linkmap_add(Obj_Entry *); 123 static void linkmap_delete(Obj_Entry *); 124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 125 static void unload_filtees(Obj_Entry *, RtldLockState *); 126 static int load_needed_objects(Obj_Entry *, int); 127 static int load_preload_objects(const char *, bool); 128 static int load_kpreload(const void *addr); 129 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 130 static void map_stacks_exec(RtldLockState *); 131 static int obj_disable_relro(Obj_Entry *); 132 static int obj_enforce_relro(Obj_Entry *); 133 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 134 static void objlist_call_init(Objlist *, RtldLockState *); 135 static void objlist_clear(Objlist *); 136 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 137 static void objlist_init(Objlist *); 138 static void objlist_push_head(Objlist *, Obj_Entry *); 139 static void objlist_push_tail(Objlist *, Obj_Entry *); 140 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 141 static void objlist_remove(Objlist *, Obj_Entry *); 142 static int open_binary_fd(const char *argv0, bool search_in_path, 143 const char **binpath_res); 144 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 145 const char **argv0, bool *dir_ignore); 146 static int parse_integer(const char *); 147 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 148 static void print_usage(const char *argv0); 149 static void release_object(Obj_Entry *); 150 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 151 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 152 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 153 int flags, RtldLockState *lockstate); 154 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 155 RtldLockState *); 156 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 157 static int rtld_dirname(const char *, char *); 158 static int rtld_dirname_abs(const char *, char *); 159 static void *rtld_dlopen(const char *name, int fd, int mode); 160 static void rtld_exit(void); 161 static void rtld_nop_exit(void); 162 static char *search_library_path(const char *, const char *, const char *, 163 int *); 164 static char *search_library_pathfds(const char *, const char *, int *); 165 static const void **get_program_var_addr(const char *, RtldLockState *); 166 static void set_program_var(const char *, const void *); 167 static int symlook_default(SymLook *, const Obj_Entry *refobj); 168 static int symlook_global(SymLook *, DoneList *); 169 static void symlook_init_from_req(SymLook *, const SymLook *); 170 static int symlook_list(SymLook *, const Objlist *, DoneList *); 171 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 172 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 173 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 174 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 175 static void trace_loaded_objects(Obj_Entry *, bool); 176 static void unlink_object(Obj_Entry *); 177 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 178 static void unref_dag(Obj_Entry *); 179 static void ref_dag(Obj_Entry *); 180 static char *origin_subst_one(Obj_Entry *, char *, const char *, 181 const char *, bool); 182 static char *origin_subst(Obj_Entry *, const char *); 183 static bool obj_resolve_origin(Obj_Entry *obj); 184 static void preinit_main(void); 185 static int rtld_verify_versions(const Objlist *); 186 static int rtld_verify_object_versions(Obj_Entry *); 187 static void object_add_name(Obj_Entry *, const char *); 188 static int object_match_name(const Obj_Entry *, const char *); 189 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 190 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 191 struct dl_phdr_info *phdr_info); 192 static uint32_t gnu_hash(const char *); 193 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 194 const unsigned long); 195 196 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 197 void _r_debug_postinit(struct link_map *) __noinline __exported; 198 199 int __sys_openat(int, const char *, int, ...); 200 201 /* 202 * Data declarations. 203 */ 204 struct r_debug r_debug __exported; /* for GDB; */ 205 static bool libmap_disable; /* Disable libmap */ 206 static bool ld_loadfltr; /* Immediate filters processing */ 207 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 208 static bool trust; /* False for setuid and setgid programs */ 209 static bool dangerous_ld_env; /* True if environment variables have been 210 used to affect the libraries loaded */ 211 bool ld_bind_not; /* Disable PLT update */ 212 static const char *ld_bind_now; /* Environment variable for immediate binding */ 213 static const char *ld_debug; /* Environment variable for debugging */ 214 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 215 weak definition */ 216 static const char *ld_library_path;/* Environment variable for search path */ 217 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 218 static const char *ld_preload; /* Environment variable for libraries to 219 load first */ 220 static const char *ld_preload_fds;/* Environment variable for libraries represented by 221 descriptors */ 222 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 223 static const char *ld_tracing; /* Called from ldd to print libs */ 224 static const char *ld_utrace; /* Use utrace() to log events. */ 225 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 226 static Obj_Entry *obj_main; /* The main program shared object */ 227 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 228 static unsigned int obj_count; /* Number of objects in obj_list */ 229 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 268 int npagesizes; 269 static int osreldate; 270 size_t *pagesizes; 271 size_t page_size; 272 273 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 274 static int max_stack_flags; 275 276 /* 277 * Global declarations normally provided by crt1. The dynamic linker is 278 * not built with crt1, so we have to provide them ourselves. 279 */ 280 char *__progname; 281 char **environ; 282 283 /* 284 * Used to pass argc, argv to init functions. 285 */ 286 int main_argc; 287 char **main_argv; 288 289 /* 290 * Globals to control TLS allocation. 291 */ 292 size_t tls_last_offset; /* Static TLS offset of last module */ 293 size_t tls_last_size; /* Static TLS size of last module */ 294 size_t tls_static_space; /* Static TLS space allocated */ 295 static size_t tls_static_max_align; 296 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 297 int tls_max_index = 1; /* Largest module index allocated */ 298 299 static bool ld_library_path_rpath = false; 300 bool ld_fast_sigblock = false; 301 302 /* 303 * Globals for path names, and such 304 */ 305 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 306 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 307 const char *ld_path_rtld = _PATH_RTLD; 308 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 309 const char *ld_env_prefix = LD_; 310 311 static void (*rtld_exit_ptr)(void); 312 313 /* 314 * Fill in a DoneList with an allocation large enough to hold all of 315 * the currently-loaded objects. Keep this as a macro since it calls 316 * alloca and we want that to occur within the scope of the caller. 317 */ 318 #define donelist_init(dlp) \ 319 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 320 assert((dlp)->objs != NULL), \ 321 (dlp)->num_alloc = obj_count, \ 322 (dlp)->num_used = 0) 323 324 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 325 if (ld_utrace != NULL) \ 326 ld_utrace_log(e, h, mb, ms, r, n); \ 327 } while (0) 328 329 static void 330 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 331 int refcnt, const char *name) 332 { 333 struct utrace_rtld ut; 334 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 335 336 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 337 ut.event = event; 338 ut.handle = handle; 339 ut.mapbase = mapbase; 340 ut.mapsize = mapsize; 341 ut.refcnt = refcnt; 342 bzero(ut.name, sizeof(ut.name)); 343 if (name) 344 strlcpy(ut.name, name, sizeof(ut.name)); 345 utrace(&ut, sizeof(ut)); 346 } 347 348 enum { 349 LD_BIND_NOW = 0, 350 LD_PRELOAD, 351 LD_LIBMAP, 352 LD_LIBRARY_PATH, 353 LD_LIBRARY_PATH_FDS, 354 LD_LIBMAP_DISABLE, 355 LD_BIND_NOT, 356 LD_DEBUG, 357 LD_ELF_HINTS_PATH, 358 LD_LOADFLTR, 359 LD_LIBRARY_PATH_RPATH, 360 LD_PRELOAD_FDS, 361 LD_DYNAMIC_WEAK, 362 LD_TRACE_LOADED_OBJECTS, 363 LD_UTRACE, 364 LD_DUMP_REL_PRE, 365 LD_DUMP_REL_POST, 366 LD_TRACE_LOADED_OBJECTS_PROGNAME, 367 LD_TRACE_LOADED_OBJECTS_FMT1, 368 LD_TRACE_LOADED_OBJECTS_FMT2, 369 LD_TRACE_LOADED_OBJECTS_ALL, 370 LD_SHOW_AUXV, 371 }; 372 373 struct ld_env_var_desc { 374 const char * const n; 375 const char *val; 376 const bool unsecure; 377 }; 378 #define LD_ENV_DESC(var, unsec) \ 379 [LD_##var] = { .n = #var, .unsecure = unsec } 380 381 static struct ld_env_var_desc ld_env_vars[] = { 382 LD_ENV_DESC(BIND_NOW, false), 383 LD_ENV_DESC(PRELOAD, true), 384 LD_ENV_DESC(LIBMAP, true), 385 LD_ENV_DESC(LIBRARY_PATH, true), 386 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 387 LD_ENV_DESC(LIBMAP_DISABLE, true), 388 LD_ENV_DESC(BIND_NOT, true), 389 LD_ENV_DESC(DEBUG, true), 390 LD_ENV_DESC(ELF_HINTS_PATH, true), 391 LD_ENV_DESC(LOADFLTR, true), 392 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 393 LD_ENV_DESC(PRELOAD_FDS, true), 394 LD_ENV_DESC(DYNAMIC_WEAK, true), 395 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 396 LD_ENV_DESC(UTRACE, false), 397 LD_ENV_DESC(DUMP_REL_PRE, false), 398 LD_ENV_DESC(DUMP_REL_POST, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 402 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 403 LD_ENV_DESC(SHOW_AUXV, false), 404 }; 405 406 static const char * 407 ld_get_env_var(int idx) 408 { 409 return (ld_env_vars[idx].val); 410 } 411 412 static const char * 413 rtld_get_env_val(char **env, const char *name, size_t name_len) 414 { 415 char **m, *n, *v; 416 417 for (m = env; *m != NULL; m++) { 418 n = *m; 419 v = strchr(n, '='); 420 if (v == NULL) { 421 /* corrupt environment? */ 422 continue; 423 } 424 if (v - n == (ptrdiff_t)name_len && 425 strncmp(name, n, name_len) == 0) 426 return (v + 1); 427 } 428 return (NULL); 429 } 430 431 static void 432 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 433 { 434 struct ld_env_var_desc *lvd; 435 size_t prefix_len, nlen; 436 char **m, *n, *v; 437 int i; 438 439 prefix_len = strlen(env_prefix); 440 for (m = env; *m != NULL; m++) { 441 n = *m; 442 if (strncmp(env_prefix, n, prefix_len) != 0) { 443 /* Not a rtld environment variable. */ 444 continue; 445 } 446 n += prefix_len; 447 v = strchr(n, '='); 448 if (v == NULL) { 449 /* corrupt environment? */ 450 continue; 451 } 452 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 453 lvd = &ld_env_vars[i]; 454 if (lvd->val != NULL) { 455 /* Saw higher-priority variable name already. */ 456 continue; 457 } 458 nlen = strlen(lvd->n); 459 if (v - n == (ptrdiff_t)nlen && 460 strncmp(lvd->n, n, nlen) == 0) { 461 lvd->val = v + 1; 462 break; 463 } 464 } 465 } 466 } 467 468 static void 469 rtld_init_env_vars(char **env) 470 { 471 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 472 } 473 474 static void 475 set_ld_elf_hints_path(void) 476 { 477 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 478 ld_elf_hints_path = ld_elf_hints_default; 479 } 480 481 uintptr_t 482 rtld_round_page(uintptr_t x) 483 { 484 return (roundup2(x, page_size)); 485 } 486 487 uintptr_t 488 rtld_trunc_page(uintptr_t x) 489 { 490 return (rounddown2(x, page_size)); 491 } 492 493 /* 494 * Main entry point for dynamic linking. The first argument is the 495 * stack pointer. The stack is expected to be laid out as described 496 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 497 * Specifically, the stack pointer points to a word containing 498 * ARGC. Following that in the stack is a null-terminated sequence 499 * of pointers to argument strings. Then comes a null-terminated 500 * sequence of pointers to environment strings. Finally, there is a 501 * sequence of "auxiliary vector" entries. 502 * 503 * The second argument points to a place to store the dynamic linker's 504 * exit procedure pointer and the third to a place to store the main 505 * program's object. 506 * 507 * The return value is the main program's entry point. 508 */ 509 func_ptr_type 510 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 511 { 512 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 513 Objlist_Entry *entry; 514 Obj_Entry *last_interposer, *obj, *preload_tail; 515 const Elf_Phdr *phdr; 516 Objlist initlist; 517 RtldLockState lockstate; 518 struct stat st; 519 Elf_Addr *argcp; 520 char **argv, **env, **envp, *kexecpath; 521 const char *argv0, *binpath, *library_path_rpath; 522 struct ld_env_var_desc *lvd; 523 caddr_t imgentry; 524 char buf[MAXPATHLEN]; 525 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 526 size_t sz; 527 #ifdef __powerpc__ 528 int old_auxv_format = 1; 529 #endif 530 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 531 532 /* 533 * On entry, the dynamic linker itself has not been relocated yet. 534 * Be very careful not to reference any global data until after 535 * init_rtld has returned. It is OK to reference file-scope statics 536 * and string constants, and to call static and global functions. 537 */ 538 539 /* Find the auxiliary vector on the stack. */ 540 argcp = sp; 541 argc = *sp++; 542 argv = (char **) sp; 543 sp += argc + 1; /* Skip over arguments and NULL terminator */ 544 env = (char **) sp; 545 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 546 ; 547 aux = (Elf_Auxinfo *) sp; 548 549 /* Digest the auxiliary vector. */ 550 for (i = 0; i < AT_COUNT; i++) 551 aux_info[i] = NULL; 552 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 553 if (auxp->a_type < AT_COUNT) 554 aux_info[auxp->a_type] = auxp; 555 #ifdef __powerpc__ 556 if (auxp->a_type == 23) /* AT_STACKPROT */ 557 old_auxv_format = 0; 558 #endif 559 } 560 561 #ifdef __powerpc__ 562 if (old_auxv_format) { 563 /* Remap from old-style auxv numbers. */ 564 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 565 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 566 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 567 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 568 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 569 aux_info[13] = NULL; /* AT_GID */ 570 571 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 572 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 573 aux_info[16] = aux_info[14]; /* AT_CANARY */ 574 aux_info[14] = NULL; /* AT_EGID */ 575 } 576 #endif 577 578 /* Initialize and relocate ourselves. */ 579 assert(aux_info[AT_BASE] != NULL); 580 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 581 582 dlerror_dflt_init(); 583 584 __progname = obj_rtld.path; 585 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 586 environ = env; 587 main_argc = argc; 588 main_argv = argv; 589 590 if (aux_info[AT_BSDFLAGS] != NULL && 591 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 592 ld_fast_sigblock = true; 593 594 trust = !issetugid(); 595 direct_exec = false; 596 597 md_abi_variant_hook(aux_info); 598 rtld_init_env_vars(env); 599 600 fd = -1; 601 if (aux_info[AT_EXECFD] != NULL) { 602 fd = aux_info[AT_EXECFD]->a_un.a_val; 603 } else { 604 assert(aux_info[AT_PHDR] != NULL); 605 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 606 if (phdr == obj_rtld.phdr) { 607 if (!trust) { 608 _rtld_error("Tainted process refusing to run binary %s", 609 argv0); 610 rtld_die(); 611 } 612 direct_exec = true; 613 614 dbg("opening main program in direct exec mode"); 615 if (argc >= 2) { 616 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 617 &argv0, &dir_ignore); 618 explicit_fd = (fd != -1); 619 binpath = NULL; 620 if (!explicit_fd) 621 fd = open_binary_fd(argv0, search_in_path, &binpath); 622 if (fstat(fd, &st) == -1) { 623 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 624 explicit_fd ? "user-provided descriptor" : argv0, 625 rtld_strerror(errno)); 626 rtld_die(); 627 } 628 629 /* 630 * Rough emulation of the permission checks done by 631 * execve(2), only Unix DACs are checked, ACLs are 632 * ignored. Preserve the semantic of disabling owner 633 * to execute if owner x bit is cleared, even if 634 * others x bit is enabled. 635 * mmap(2) does not allow to mmap with PROT_EXEC if 636 * binary' file comes from noexec mount. We cannot 637 * set a text reference on the binary. 638 */ 639 dir_enable = false; 640 if (st.st_uid == geteuid()) { 641 if ((st.st_mode & S_IXUSR) != 0) 642 dir_enable = true; 643 } else if (st.st_gid == getegid()) { 644 if ((st.st_mode & S_IXGRP) != 0) 645 dir_enable = true; 646 } else if ((st.st_mode & S_IXOTH) != 0) { 647 dir_enable = true; 648 } 649 if (!dir_enable && !dir_ignore) { 650 _rtld_error("No execute permission for binary %s", 651 argv0); 652 rtld_die(); 653 } 654 655 /* 656 * For direct exec mode, argv[0] is the interpreter 657 * name, we must remove it and shift arguments left 658 * before invoking binary main. Since stack layout 659 * places environment pointers and aux vectors right 660 * after the terminating NULL, we must shift 661 * environment and aux as well. 662 */ 663 main_argc = argc - rtld_argc; 664 for (i = 0; i <= main_argc; i++) 665 argv[i] = argv[i + rtld_argc]; 666 *argcp -= rtld_argc; 667 environ = env = envp = argv + main_argc + 1; 668 dbg("move env from %p to %p", envp + rtld_argc, envp); 669 do { 670 *envp = *(envp + rtld_argc); 671 } while (*envp++ != NULL); 672 aux = auxp = (Elf_Auxinfo *)envp; 673 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 674 dbg("move aux from %p to %p", auxpf, aux); 675 /* XXXKIB insert place for AT_EXECPATH if not present */ 676 for (;; auxp++, auxpf++) { 677 *auxp = *auxpf; 678 if (auxp->a_type == AT_NULL) 679 break; 680 } 681 /* Since the auxiliary vector has moved, redigest it. */ 682 for (i = 0; i < AT_COUNT; i++) 683 aux_info[i] = NULL; 684 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 685 if (auxp->a_type < AT_COUNT) 686 aux_info[auxp->a_type] = auxp; 687 } 688 689 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 690 if (binpath == NULL) { 691 aux_info[AT_EXECPATH] = NULL; 692 } else { 693 if (aux_info[AT_EXECPATH] == NULL) { 694 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 695 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 696 } 697 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 698 binpath); 699 } 700 } else { 701 _rtld_error("No binary"); 702 rtld_die(); 703 } 704 } 705 } 706 707 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 708 709 /* 710 * If the process is tainted, then we un-set the dangerous environment 711 * variables. The process will be marked as tainted until setuid(2) 712 * is called. If any child process calls setuid(2) we do not want any 713 * future processes to honor the potentially un-safe variables. 714 */ 715 if (!trust) { 716 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 717 lvd = &ld_env_vars[i]; 718 if (lvd->unsecure) 719 lvd->val = NULL; 720 } 721 } 722 723 ld_debug = ld_get_env_var(LD_DEBUG); 724 if (ld_bind_now == NULL) 725 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 726 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 727 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 728 libmap_override = ld_get_env_var(LD_LIBMAP); 729 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 730 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 731 ld_preload = ld_get_env_var(LD_PRELOAD); 732 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 733 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 734 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 735 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 736 if (library_path_rpath != NULL) { 737 if (library_path_rpath[0] == 'y' || 738 library_path_rpath[0] == 'Y' || 739 library_path_rpath[0] == '1') 740 ld_library_path_rpath = true; 741 else 742 ld_library_path_rpath = false; 743 } 744 dangerous_ld_env = libmap_disable || libmap_override != NULL || 745 ld_library_path != NULL || ld_preload != NULL || 746 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 747 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 748 ld_utrace = ld_get_env_var(LD_UTRACE); 749 750 set_ld_elf_hints_path(); 751 if (ld_debug != NULL && *ld_debug != '\0') 752 debug = 1; 753 dbg("%s is initialized, base address = %p", __progname, 754 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 755 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 756 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 757 758 dbg("initializing thread locks"); 759 lockdflt_init(); 760 761 /* 762 * Load the main program, or process its program header if it is 763 * already loaded. 764 */ 765 if (fd != -1) { /* Load the main program. */ 766 dbg("loading main program"); 767 obj_main = map_object(fd, argv0, NULL); 768 close(fd); 769 if (obj_main == NULL) 770 rtld_die(); 771 max_stack_flags = obj_main->stack_flags; 772 } else { /* Main program already loaded. */ 773 dbg("processing main program's program header"); 774 assert(aux_info[AT_PHDR] != NULL); 775 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 776 assert(aux_info[AT_PHNUM] != NULL); 777 phnum = aux_info[AT_PHNUM]->a_un.a_val; 778 assert(aux_info[AT_PHENT] != NULL); 779 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 780 assert(aux_info[AT_ENTRY] != NULL); 781 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 782 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 783 rtld_die(); 784 } 785 786 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 787 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 788 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 789 if (kexecpath[0] == '/') 790 obj_main->path = kexecpath; 791 else if (getcwd(buf, sizeof(buf)) == NULL || 792 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 793 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 794 obj_main->path = xstrdup(argv0); 795 else 796 obj_main->path = xstrdup(buf); 797 } else { 798 dbg("No AT_EXECPATH or direct exec"); 799 obj_main->path = xstrdup(argv0); 800 } 801 dbg("obj_main path %s", obj_main->path); 802 obj_main->mainprog = true; 803 804 if (aux_info[AT_STACKPROT] != NULL && 805 aux_info[AT_STACKPROT]->a_un.a_val != 0) 806 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 807 808 #ifndef COMPAT_32BIT 809 /* 810 * Get the actual dynamic linker pathname from the executable if 811 * possible. (It should always be possible.) That ensures that 812 * gdb will find the right dynamic linker even if a non-standard 813 * one is being used. 814 */ 815 if (obj_main->interp != NULL && 816 strcmp(obj_main->interp, obj_rtld.path) != 0) { 817 free(obj_rtld.path); 818 obj_rtld.path = xstrdup(obj_main->interp); 819 __progname = obj_rtld.path; 820 } 821 #endif 822 823 if (!digest_dynamic(obj_main, 0)) 824 rtld_die(); 825 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 826 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 827 obj_main->dynsymcount); 828 829 linkmap_add(obj_main); 830 linkmap_add(&obj_rtld); 831 832 /* Link the main program into the list of objects. */ 833 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 834 obj_count++; 835 obj_loads++; 836 837 /* Initialize a fake symbol for resolving undefined weak references. */ 838 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 839 sym_zero.st_shndx = SHN_UNDEF; 840 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 841 842 if (!libmap_disable) 843 libmap_disable = (bool)lm_init(libmap_override); 844 845 if (aux_info[AT_KPRELOAD] != NULL && 846 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 847 dbg("loading kernel vdso"); 848 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 849 rtld_die(); 850 } 851 852 dbg("loading LD_PRELOAD_FDS libraries"); 853 if (load_preload_objects(ld_preload_fds, true) == -1) 854 rtld_die(); 855 856 dbg("loading LD_PRELOAD libraries"); 857 if (load_preload_objects(ld_preload, false) == -1) 858 rtld_die(); 859 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 860 861 dbg("loading needed objects"); 862 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 863 0) == -1) 864 rtld_die(); 865 866 /* Make a list of all objects loaded at startup. */ 867 last_interposer = obj_main; 868 TAILQ_FOREACH(obj, &obj_list, next) { 869 if (obj->marker) 870 continue; 871 if (obj->z_interpose && obj != obj_main) { 872 objlist_put_after(&list_main, last_interposer, obj); 873 last_interposer = obj; 874 } else { 875 objlist_push_tail(&list_main, obj); 876 } 877 obj->refcount++; 878 } 879 880 dbg("checking for required versions"); 881 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 882 rtld_die(); 883 884 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 885 dump_auxv(aux_info); 886 887 if (ld_tracing) { /* We're done */ 888 trace_loaded_objects(obj_main, true); 889 exit(0); 890 } 891 892 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 893 dump_relocations(obj_main); 894 exit (0); 895 } 896 897 /* 898 * Processing tls relocations requires having the tls offsets 899 * initialized. Prepare offsets before starting initial 900 * relocation processing. 901 */ 902 dbg("initializing initial thread local storage offsets"); 903 STAILQ_FOREACH(entry, &list_main, link) { 904 /* 905 * Allocate all the initial objects out of the static TLS 906 * block even if they didn't ask for it. 907 */ 908 allocate_tls_offset(entry->obj); 909 } 910 911 if (relocate_objects(obj_main, 912 ld_bind_now != NULL && *ld_bind_now != '\0', 913 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 914 rtld_die(); 915 916 dbg("doing copy relocations"); 917 if (do_copy_relocations(obj_main) == -1) 918 rtld_die(); 919 920 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 921 dump_relocations(obj_main); 922 exit (0); 923 } 924 925 ifunc_init(aux); 926 927 /* 928 * Setup TLS for main thread. This must be done after the 929 * relocations are processed, since tls initialization section 930 * might be the subject for relocations. 931 */ 932 dbg("initializing initial thread local storage"); 933 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 934 935 dbg("initializing key program variables"); 936 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 937 set_program_var("environ", env); 938 set_program_var("__elf_aux_vector", aux); 939 940 /* Make a list of init functions to call. */ 941 objlist_init(&initlist); 942 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 943 preload_tail, &initlist); 944 945 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 946 947 map_stacks_exec(NULL); 948 949 if (!obj_main->crt_no_init) { 950 /* 951 * Make sure we don't call the main program's init and fini 952 * functions for binaries linked with old crt1 which calls 953 * _init itself. 954 */ 955 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 956 obj_main->preinit_array = obj_main->init_array = 957 obj_main->fini_array = (Elf_Addr)NULL; 958 } 959 960 if (direct_exec) { 961 /* Set osrel for direct-execed binary */ 962 mib[0] = CTL_KERN; 963 mib[1] = KERN_PROC; 964 mib[2] = KERN_PROC_OSREL; 965 mib[3] = getpid(); 966 osrel = obj_main->osrel; 967 sz = sizeof(old_osrel); 968 dbg("setting osrel to %d", osrel); 969 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 970 } 971 972 wlock_acquire(rtld_bind_lock, &lockstate); 973 974 dbg("resolving ifuncs"); 975 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 976 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 977 rtld_die(); 978 979 rtld_exit_ptr = rtld_exit; 980 if (obj_main->crt_no_init) 981 preinit_main(); 982 objlist_call_init(&initlist, &lockstate); 983 _r_debug_postinit(&obj_main->linkmap); 984 objlist_clear(&initlist); 985 dbg("loading filtees"); 986 TAILQ_FOREACH(obj, &obj_list, next) { 987 if (obj->marker) 988 continue; 989 if (ld_loadfltr || obj->z_loadfltr) 990 load_filtees(obj, 0, &lockstate); 991 } 992 993 dbg("enforcing main obj relro"); 994 if (obj_enforce_relro(obj_main) == -1) 995 rtld_die(); 996 997 lock_release(rtld_bind_lock, &lockstate); 998 999 dbg("transferring control to program entry point = %p", obj_main->entry); 1000 1001 /* Return the exit procedure and the program entry point. */ 1002 *exit_proc = rtld_exit_ptr; 1003 *objp = obj_main; 1004 return ((func_ptr_type)obj_main->entry); 1005 } 1006 1007 void * 1008 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 1009 { 1010 void *ptr; 1011 Elf_Addr target; 1012 1013 ptr = (void *)make_function_pointer(def, obj); 1014 target = call_ifunc_resolver(ptr); 1015 return ((void *)target); 1016 } 1017 1018 Elf_Addr 1019 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1020 { 1021 const Elf_Rel *rel; 1022 const Elf_Sym *def; 1023 const Obj_Entry *defobj; 1024 Elf_Addr *where; 1025 Elf_Addr target; 1026 RtldLockState lockstate; 1027 1028 rlock_acquire(rtld_bind_lock, &lockstate); 1029 if (sigsetjmp(lockstate.env, 0) != 0) 1030 lock_upgrade(rtld_bind_lock, &lockstate); 1031 if (obj->pltrel) 1032 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1033 else 1034 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1035 1036 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1037 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1038 NULL, &lockstate); 1039 if (def == NULL) 1040 rtld_die(); 1041 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1042 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1043 else 1044 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1045 1046 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1047 defobj->strtab + def->st_name, 1048 obj->path == NULL ? NULL : basename(obj->path), 1049 (void *)target, 1050 defobj->path == NULL ? NULL : basename(defobj->path)); 1051 1052 /* 1053 * Write the new contents for the jmpslot. Note that depending on 1054 * architecture, the value which we need to return back to the 1055 * lazy binding trampoline may or may not be the target 1056 * address. The value returned from reloc_jmpslot() is the value 1057 * that the trampoline needs. 1058 */ 1059 target = reloc_jmpslot(where, target, defobj, obj, rel); 1060 lock_release(rtld_bind_lock, &lockstate); 1061 return (target); 1062 } 1063 1064 /* 1065 * Error reporting function. Use it like printf. If formats the message 1066 * into a buffer, and sets things up so that the next call to dlerror() 1067 * will return the message. 1068 */ 1069 void 1070 _rtld_error(const char *fmt, ...) 1071 { 1072 va_list ap; 1073 1074 va_start(ap, fmt); 1075 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1076 fmt, ap); 1077 va_end(ap); 1078 *lockinfo.dlerror_seen() = 0; 1079 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1080 } 1081 1082 /* 1083 * Return a dynamically-allocated copy of the current error message, if any. 1084 */ 1085 static struct dlerror_save * 1086 errmsg_save(void) 1087 { 1088 struct dlerror_save *res; 1089 1090 res = xmalloc(sizeof(*res)); 1091 res->seen = *lockinfo.dlerror_seen(); 1092 if (res->seen == 0) 1093 res->msg = xstrdup(lockinfo.dlerror_loc()); 1094 return (res); 1095 } 1096 1097 /* 1098 * Restore the current error message from a copy which was previously saved 1099 * by errmsg_save(). The copy is freed. 1100 */ 1101 static void 1102 errmsg_restore(struct dlerror_save *saved_msg) 1103 { 1104 if (saved_msg == NULL || saved_msg->seen == 1) { 1105 *lockinfo.dlerror_seen() = 1; 1106 } else { 1107 *lockinfo.dlerror_seen() = 0; 1108 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1109 lockinfo.dlerror_loc_sz); 1110 free(saved_msg->msg); 1111 } 1112 free(saved_msg); 1113 } 1114 1115 static const char * 1116 basename(const char *name) 1117 { 1118 const char *p; 1119 1120 p = strrchr(name, '/'); 1121 return (p != NULL ? p + 1 : name); 1122 } 1123 1124 static struct utsname uts; 1125 1126 static char * 1127 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1128 const char *subst, bool may_free) 1129 { 1130 char *p, *p1, *res, *resp; 1131 int subst_len, kw_len, subst_count, old_len, new_len; 1132 1133 kw_len = strlen(kw); 1134 1135 /* 1136 * First, count the number of the keyword occurrences, to 1137 * preallocate the final string. 1138 */ 1139 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1140 p1 = strstr(p, kw); 1141 if (p1 == NULL) 1142 break; 1143 } 1144 1145 /* 1146 * If the keyword is not found, just return. 1147 * 1148 * Return non-substituted string if resolution failed. We 1149 * cannot do anything more reasonable, the failure mode of the 1150 * caller is unresolved library anyway. 1151 */ 1152 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1153 return (may_free ? real : xstrdup(real)); 1154 if (obj != NULL) 1155 subst = obj->origin_path; 1156 1157 /* 1158 * There is indeed something to substitute. Calculate the 1159 * length of the resulting string, and allocate it. 1160 */ 1161 subst_len = strlen(subst); 1162 old_len = strlen(real); 1163 new_len = old_len + (subst_len - kw_len) * subst_count; 1164 res = xmalloc(new_len + 1); 1165 1166 /* 1167 * Now, execute the substitution loop. 1168 */ 1169 for (p = real, resp = res, *resp = '\0';;) { 1170 p1 = strstr(p, kw); 1171 if (p1 != NULL) { 1172 /* Copy the prefix before keyword. */ 1173 memcpy(resp, p, p1 - p); 1174 resp += p1 - p; 1175 /* Keyword replacement. */ 1176 memcpy(resp, subst, subst_len); 1177 resp += subst_len; 1178 *resp = '\0'; 1179 p = p1 + kw_len; 1180 } else 1181 break; 1182 } 1183 1184 /* Copy to the end of string and finish. */ 1185 strcat(resp, p); 1186 if (may_free) 1187 free(real); 1188 return (res); 1189 } 1190 1191 static const struct { 1192 const char *kw; 1193 bool pass_obj; 1194 const char *subst; 1195 } tokens[] = { 1196 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1197 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1198 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1199 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1200 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1201 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1202 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1203 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 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 * Hash function for symbol table lookup. Don't even think about changing 1799 * this. It is specified by the System V ABI. 1800 */ 1801 unsigned long 1802 elf_hash(const char *name) 1803 { 1804 const unsigned char *p = (const unsigned char *) name; 1805 unsigned long h = 0; 1806 unsigned long g; 1807 1808 while (*p != '\0') { 1809 h = (h << 4) + *p++; 1810 if ((g = h & 0xf0000000) != 0) 1811 h ^= g >> 24; 1812 h &= ~g; 1813 } 1814 return (h); 1815 } 1816 1817 /* 1818 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1819 * unsigned in case it's implemented with a wider type. 1820 */ 1821 static uint32_t 1822 gnu_hash(const char *s) 1823 { 1824 uint32_t h; 1825 unsigned char c; 1826 1827 h = 5381; 1828 for (c = *s; c != '\0'; c = *++s) 1829 h = h * 33 + c; 1830 return (h & 0xffffffff); 1831 } 1832 1833 1834 /* 1835 * Find the library with the given name, and return its full pathname. 1836 * The returned string is dynamically allocated. Generates an error 1837 * message and returns NULL if the library cannot be found. 1838 * 1839 * If the second argument is non-NULL, then it refers to an already- 1840 * loaded shared object, whose library search path will be searched. 1841 * 1842 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1843 * descriptor (which is close-on-exec) will be passed out via the third 1844 * argument. 1845 * 1846 * The search order is: 1847 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1848 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1849 * LD_LIBRARY_PATH 1850 * DT_RUNPATH in the referencing file 1851 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1852 * from list) 1853 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1854 * 1855 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1856 */ 1857 static char * 1858 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1859 { 1860 char *pathname, *refobj_path; 1861 const char *name; 1862 bool nodeflib, objgiven; 1863 1864 objgiven = refobj != NULL; 1865 1866 if (libmap_disable || !objgiven || 1867 (name = lm_find(refobj->path, xname)) == NULL) 1868 name = xname; 1869 1870 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1871 if (name[0] != '/' && !trust) { 1872 _rtld_error("Absolute pathname required " 1873 "for shared object \"%s\"", name); 1874 return (NULL); 1875 } 1876 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1877 __DECONST(char *, name))); 1878 } 1879 1880 dbg(" Searching for \"%s\"", name); 1881 refobj_path = objgiven ? refobj->path : NULL; 1882 1883 /* 1884 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1885 * back to pre-conforming behaviour if user requested so with 1886 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1887 * nodeflib. 1888 */ 1889 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1890 pathname = search_library_path(name, ld_library_path, 1891 refobj_path, fdp); 1892 if (pathname != NULL) 1893 return (pathname); 1894 if (refobj != NULL) { 1895 pathname = search_library_path(name, refobj->rpath, 1896 refobj_path, fdp); 1897 if (pathname != NULL) 1898 return (pathname); 1899 } 1900 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1901 if (pathname != NULL) 1902 return (pathname); 1903 pathname = search_library_path(name, gethints(false), 1904 refobj_path, fdp); 1905 if (pathname != NULL) 1906 return (pathname); 1907 pathname = search_library_path(name, ld_standard_library_path, 1908 refobj_path, fdp); 1909 if (pathname != NULL) 1910 return (pathname); 1911 } else { 1912 nodeflib = objgiven ? refobj->z_nodeflib : false; 1913 if (objgiven) { 1914 pathname = search_library_path(name, refobj->rpath, 1915 refobj->path, fdp); 1916 if (pathname != NULL) 1917 return (pathname); 1918 } 1919 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1920 pathname = search_library_path(name, obj_main->rpath, 1921 refobj_path, fdp); 1922 if (pathname != NULL) 1923 return (pathname); 1924 } 1925 pathname = search_library_path(name, ld_library_path, 1926 refobj_path, fdp); 1927 if (pathname != NULL) 1928 return (pathname); 1929 if (objgiven) { 1930 pathname = search_library_path(name, refobj->runpath, 1931 refobj_path, fdp); 1932 if (pathname != NULL) 1933 return (pathname); 1934 } 1935 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1936 if (pathname != NULL) 1937 return (pathname); 1938 pathname = search_library_path(name, gethints(nodeflib), 1939 refobj_path, fdp); 1940 if (pathname != NULL) 1941 return (pathname); 1942 if (objgiven && !nodeflib) { 1943 pathname = search_library_path(name, 1944 ld_standard_library_path, refobj_path, fdp); 1945 if (pathname != NULL) 1946 return (pathname); 1947 } 1948 } 1949 1950 if (objgiven && refobj->path != NULL) { 1951 _rtld_error("Shared object \"%s\" not found, " 1952 "required by \"%s\"", name, basename(refobj->path)); 1953 } else { 1954 _rtld_error("Shared object \"%s\" not found", name); 1955 } 1956 return (NULL); 1957 } 1958 1959 /* 1960 * Given a symbol number in a referencing object, find the corresponding 1961 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1962 * no definition was found. Returns a pointer to the Obj_Entry of the 1963 * defining object via the reference parameter DEFOBJ_OUT. 1964 */ 1965 const Elf_Sym * 1966 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1967 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1968 RtldLockState *lockstate) 1969 { 1970 const Elf_Sym *ref; 1971 const Elf_Sym *def; 1972 const Obj_Entry *defobj; 1973 const Ver_Entry *ve; 1974 SymLook req; 1975 const char *name; 1976 int res; 1977 1978 /* 1979 * If we have already found this symbol, get the information from 1980 * the cache. 1981 */ 1982 if (symnum >= refobj->dynsymcount) 1983 return (NULL); /* Bad object */ 1984 if (cache != NULL && cache[symnum].sym != NULL) { 1985 *defobj_out = cache[symnum].obj; 1986 return (cache[symnum].sym); 1987 } 1988 1989 ref = refobj->symtab + symnum; 1990 name = refobj->strtab + ref->st_name; 1991 def = NULL; 1992 defobj = NULL; 1993 ve = NULL; 1994 1995 /* 1996 * We don't have to do a full scale lookup if the symbol is local. 1997 * We know it will bind to the instance in this load module; to 1998 * which we already have a pointer (ie ref). By not doing a lookup, 1999 * we not only improve performance, but it also avoids unresolvable 2000 * symbols when local symbols are not in the hash table. This has 2001 * been seen with the ia64 toolchain. 2002 */ 2003 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2004 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2005 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2006 symnum); 2007 } 2008 symlook_init(&req, name); 2009 req.flags = flags; 2010 ve = req.ventry = fetch_ventry(refobj, symnum); 2011 req.lockstate = lockstate; 2012 res = symlook_default(&req, refobj); 2013 if (res == 0) { 2014 def = req.sym_out; 2015 defobj = req.defobj_out; 2016 } 2017 } else { 2018 def = ref; 2019 defobj = refobj; 2020 } 2021 2022 /* 2023 * If we found no definition and the reference is weak, treat the 2024 * symbol as having the value zero. 2025 */ 2026 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2027 def = &sym_zero; 2028 defobj = obj_main; 2029 } 2030 2031 if (def != NULL) { 2032 *defobj_out = defobj; 2033 /* Record the information in the cache to avoid subsequent lookups. */ 2034 if (cache != NULL) { 2035 cache[symnum].sym = def; 2036 cache[symnum].obj = defobj; 2037 } 2038 } else { 2039 if (refobj != &obj_rtld) 2040 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2041 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2042 } 2043 return (def); 2044 } 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 bool skip; 2070 2071 /* First call, read the hints file */ 2072 if (hints == NULL) { 2073 /* Keep from trying again in case the hints file is bad. */ 2074 hints = ""; 2075 2076 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2077 return (NULL); 2078 2079 /* 2080 * Check of hdr.dirlistlen value against type limit 2081 * intends to pacify static analyzers. Further 2082 * paranoia leads to checks that dirlist is fully 2083 * contained in the file range. 2084 */ 2085 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2086 hdr.magic != ELFHINTS_MAGIC || 2087 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2088 fstat(fd, &hint_stat) == -1) { 2089 cleanup1: 2090 close(fd); 2091 hdr.dirlistlen = 0; 2092 return (NULL); 2093 } 2094 dl = hdr.strtab; 2095 if (dl + hdr.dirlist < dl) 2096 goto cleanup1; 2097 dl += hdr.dirlist; 2098 if (dl + hdr.dirlistlen < dl) 2099 goto cleanup1; 2100 dl += hdr.dirlistlen; 2101 if (dl > hint_stat.st_size) 2102 goto cleanup1; 2103 p = xmalloc(hdr.dirlistlen + 1); 2104 if (pread(fd, p, hdr.dirlistlen + 1, 2105 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2106 p[hdr.dirlistlen] != '\0') { 2107 free(p); 2108 goto cleanup1; 2109 } 2110 hints = p; 2111 close(fd); 2112 } 2113 2114 /* 2115 * If caller agreed to receive list which includes the default 2116 * paths, we are done. Otherwise, if we still did not 2117 * calculated filtered result, do it now. 2118 */ 2119 if (!nostdlib) 2120 return (hints[0] != '\0' ? hints : NULL); 2121 if (filtered_path != NULL) 2122 goto filt_ret; 2123 2124 /* 2125 * Obtain the list of all configured search paths, and the 2126 * list of the default paths. 2127 * 2128 * First estimate the size of the results. 2129 */ 2130 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2131 smeta.dls_cnt = 0; 2132 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2133 hmeta.dls_cnt = 0; 2134 2135 sargs.request = RTLD_DI_SERINFOSIZE; 2136 sargs.serinfo = &smeta; 2137 hargs.request = RTLD_DI_SERINFOSIZE; 2138 hargs.serinfo = &hmeta; 2139 2140 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2141 &sargs); 2142 path_enumerate(hints, fill_search_info, NULL, &hargs); 2143 2144 SLPinfo = xmalloc(smeta.dls_size); 2145 hintinfo = xmalloc(hmeta.dls_size); 2146 2147 /* 2148 * Next fetch both sets of paths. 2149 */ 2150 sargs.request = RTLD_DI_SERINFO; 2151 sargs.serinfo = SLPinfo; 2152 sargs.serpath = &SLPinfo->dls_serpath[0]; 2153 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2154 2155 hargs.request = RTLD_DI_SERINFO; 2156 hargs.serinfo = hintinfo; 2157 hargs.serpath = &hintinfo->dls_serpath[0]; 2158 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2159 2160 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2161 &sargs); 2162 path_enumerate(hints, fill_search_info, NULL, &hargs); 2163 2164 /* 2165 * Now calculate the difference between two sets, by excluding 2166 * standard paths from the full set. 2167 */ 2168 fndx = 0; 2169 fcount = 0; 2170 filtered_path = xmalloc(hdr.dirlistlen + 1); 2171 hintpath = &hintinfo->dls_serpath[0]; 2172 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2173 skip = false; 2174 SLPpath = &SLPinfo->dls_serpath[0]; 2175 /* 2176 * Check each standard path against current. 2177 */ 2178 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2179 /* matched, skip the path */ 2180 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2181 skip = true; 2182 break; 2183 } 2184 } 2185 if (skip) 2186 continue; 2187 /* 2188 * Not matched against any standard path, add the path 2189 * to result. Separate consequtive paths with ':'. 2190 */ 2191 if (fcount > 0) { 2192 filtered_path[fndx] = ':'; 2193 fndx++; 2194 } 2195 fcount++; 2196 flen = strlen(hintpath->dls_name); 2197 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2198 fndx += flen; 2199 } 2200 filtered_path[fndx] = '\0'; 2201 2202 free(SLPinfo); 2203 free(hintinfo); 2204 2205 filt_ret: 2206 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2207 } 2208 2209 static void 2210 init_dag(Obj_Entry *root) 2211 { 2212 const Needed_Entry *needed; 2213 const Objlist_Entry *elm; 2214 DoneList donelist; 2215 2216 if (root->dag_inited) 2217 return; 2218 donelist_init(&donelist); 2219 2220 /* Root object belongs to own DAG. */ 2221 objlist_push_tail(&root->dldags, root); 2222 objlist_push_tail(&root->dagmembers, root); 2223 donelist_check(&donelist, root); 2224 2225 /* 2226 * Add dependencies of root object to DAG in breadth order 2227 * by exploiting the fact that each new object get added 2228 * to the tail of the dagmembers list. 2229 */ 2230 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2231 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2232 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2233 continue; 2234 objlist_push_tail(&needed->obj->dldags, root); 2235 objlist_push_tail(&root->dagmembers, needed->obj); 2236 } 2237 } 2238 root->dag_inited = true; 2239 } 2240 2241 static void 2242 init_marker(Obj_Entry *marker) 2243 { 2244 2245 bzero(marker, sizeof(*marker)); 2246 marker->marker = true; 2247 } 2248 2249 Obj_Entry * 2250 globallist_curr(const Obj_Entry *obj) 2251 { 2252 2253 for (;;) { 2254 if (obj == NULL) 2255 return (NULL); 2256 if (!obj->marker) 2257 return (__DECONST(Obj_Entry *, obj)); 2258 obj = TAILQ_PREV(obj, obj_entry_q, next); 2259 } 2260 } 2261 2262 Obj_Entry * 2263 globallist_next(const Obj_Entry *obj) 2264 { 2265 2266 for (;;) { 2267 obj = TAILQ_NEXT(obj, next); 2268 if (obj == NULL) 2269 return (NULL); 2270 if (!obj->marker) 2271 return (__DECONST(Obj_Entry *, obj)); 2272 } 2273 } 2274 2275 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2276 static void 2277 hold_object(Obj_Entry *obj) 2278 { 2279 2280 obj->holdcount++; 2281 } 2282 2283 static void 2284 unhold_object(Obj_Entry *obj) 2285 { 2286 2287 assert(obj->holdcount > 0); 2288 if (--obj->holdcount == 0 && obj->unholdfree) 2289 release_object(obj); 2290 } 2291 2292 static void 2293 process_z(Obj_Entry *root) 2294 { 2295 const Objlist_Entry *elm; 2296 Obj_Entry *obj; 2297 2298 /* 2299 * Walk over object DAG and process every dependent object 2300 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2301 * to grow their own DAG. 2302 * 2303 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2304 * symlook_global() to work. 2305 * 2306 * For DF_1_NODELETE, the DAG should have its reference upped. 2307 */ 2308 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2309 obj = elm->obj; 2310 if (obj == NULL) 2311 continue; 2312 if (obj->z_nodelete && !obj->ref_nodel) { 2313 dbg("obj %s -z nodelete", obj->path); 2314 init_dag(obj); 2315 ref_dag(obj); 2316 obj->ref_nodel = true; 2317 } 2318 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2319 dbg("obj %s -z global", obj->path); 2320 objlist_push_tail(&list_global, obj); 2321 init_dag(obj); 2322 } 2323 } 2324 } 2325 2326 static void 2327 parse_rtld_phdr(Obj_Entry *obj) 2328 { 2329 const Elf_Phdr *ph; 2330 Elf_Addr note_start, note_end; 2331 2332 obj->stack_flags = PF_X | PF_R | PF_W; 2333 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2334 obj->phsize; ph++) { 2335 switch (ph->p_type) { 2336 case PT_GNU_STACK: 2337 obj->stack_flags = ph->p_flags; 2338 break; 2339 case PT_GNU_RELRO: 2340 obj->relro_page = obj->relocbase + 2341 rtld_trunc_page(ph->p_vaddr); 2342 obj->relro_size = rtld_round_page(ph->p_memsz); 2343 break; 2344 case PT_NOTE: 2345 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2346 note_end = note_start + ph->p_filesz; 2347 digest_notes(obj, note_start, note_end); 2348 break; 2349 } 2350 } 2351 } 2352 2353 /* 2354 * Initialize the dynamic linker. The argument is the address at which 2355 * the dynamic linker has been mapped into memory. The primary task of 2356 * this function is to relocate the dynamic linker. 2357 */ 2358 static void 2359 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2360 { 2361 Obj_Entry objtmp; /* Temporary rtld object */ 2362 const Elf_Ehdr *ehdr; 2363 const Elf_Dyn *dyn_rpath; 2364 const Elf_Dyn *dyn_soname; 2365 const Elf_Dyn *dyn_runpath; 2366 2367 #ifdef RTLD_INIT_PAGESIZES_EARLY 2368 /* The page size is required by the dynamic memory allocator. */ 2369 init_pagesizes(aux_info); 2370 #endif 2371 2372 /* 2373 * Conjure up an Obj_Entry structure for the dynamic linker. 2374 * 2375 * The "path" member can't be initialized yet because string constants 2376 * cannot yet be accessed. Below we will set it correctly. 2377 */ 2378 memset(&objtmp, 0, sizeof(objtmp)); 2379 objtmp.path = NULL; 2380 objtmp.rtld = true; 2381 objtmp.mapbase = mapbase; 2382 #ifdef PIC 2383 objtmp.relocbase = mapbase; 2384 #endif 2385 2386 objtmp.dynamic = rtld_dynamic(&objtmp); 2387 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2388 assert(objtmp.needed == NULL); 2389 assert(!objtmp.textrel); 2390 /* 2391 * Temporarily put the dynamic linker entry into the object list, so 2392 * that symbols can be found. 2393 */ 2394 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2395 2396 ehdr = (Elf_Ehdr *)mapbase; 2397 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2398 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2399 2400 /* Initialize the object list. */ 2401 TAILQ_INIT(&obj_list); 2402 2403 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2404 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2405 2406 #ifndef RTLD_INIT_PAGESIZES_EARLY 2407 /* The page size is required by the dynamic memory allocator. */ 2408 init_pagesizes(aux_info); 2409 #endif 2410 2411 if (aux_info[AT_OSRELDATE] != NULL) 2412 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2413 2414 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2415 2416 /* Replace the path with a dynamically allocated copy. */ 2417 obj_rtld.path = xstrdup(ld_path_rtld); 2418 2419 parse_rtld_phdr(&obj_rtld); 2420 if (obj_enforce_relro(&obj_rtld) == -1) 2421 rtld_die(); 2422 2423 r_debug.r_version = R_DEBUG_VERSION; 2424 r_debug.r_brk = r_debug_state; 2425 r_debug.r_state = RT_CONSISTENT; 2426 r_debug.r_ldbase = obj_rtld.relocbase; 2427 } 2428 2429 /* 2430 * Retrieve the array of supported page sizes. The kernel provides the page 2431 * sizes in increasing order. 2432 */ 2433 static void 2434 init_pagesizes(Elf_Auxinfo **aux_info) 2435 { 2436 static size_t psa[MAXPAGESIZES]; 2437 int mib[2]; 2438 size_t len, size; 2439 2440 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2441 NULL) { 2442 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2443 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2444 } else { 2445 len = 2; 2446 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2447 size = sizeof(psa); 2448 else { 2449 /* As a fallback, retrieve the base page size. */ 2450 size = sizeof(psa[0]); 2451 if (aux_info[AT_PAGESZ] != NULL) { 2452 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2453 goto psa_filled; 2454 } else { 2455 mib[0] = CTL_HW; 2456 mib[1] = HW_PAGESIZE; 2457 len = 2; 2458 } 2459 } 2460 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2461 _rtld_error("sysctl for hw.pagesize(s) failed"); 2462 rtld_die(); 2463 } 2464 psa_filled: 2465 pagesizes = psa; 2466 } 2467 npagesizes = size / sizeof(pagesizes[0]); 2468 /* Discard any invalid entries at the end of the array. */ 2469 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2470 npagesizes--; 2471 2472 page_size = pagesizes[0]; 2473 } 2474 2475 /* 2476 * Add the init functions from a needed object list (and its recursive 2477 * needed objects) to "list". This is not used directly; it is a helper 2478 * function for initlist_add_objects(). The write lock must be held 2479 * when this function is called. 2480 */ 2481 static void 2482 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2483 { 2484 /* Recursively process the successor needed objects. */ 2485 if (needed->next != NULL) 2486 initlist_add_neededs(needed->next, list); 2487 2488 /* Process the current needed object. */ 2489 if (needed->obj != NULL) 2490 initlist_add_objects(needed->obj, needed->obj, list); 2491 } 2492 2493 /* 2494 * Scan all of the DAGs rooted in the range of objects from "obj" to 2495 * "tail" and add their init functions to "list". This recurses over 2496 * the DAGs and ensure the proper init ordering such that each object's 2497 * needed libraries are initialized before the object itself. At the 2498 * same time, this function adds the objects to the global finalization 2499 * list "list_fini" in the opposite order. The write lock must be 2500 * held when this function is called. 2501 */ 2502 static void 2503 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2504 { 2505 Obj_Entry *nobj; 2506 2507 if (obj->init_scanned || obj->init_done) 2508 return; 2509 obj->init_scanned = true; 2510 2511 /* Recursively process the successor objects. */ 2512 nobj = globallist_next(obj); 2513 if (nobj != NULL && obj != tail) 2514 initlist_add_objects(nobj, tail, list); 2515 2516 /* Recursively process the needed objects. */ 2517 if (obj->needed != NULL) 2518 initlist_add_neededs(obj->needed, list); 2519 if (obj->needed_filtees != NULL) 2520 initlist_add_neededs(obj->needed_filtees, list); 2521 if (obj->needed_aux_filtees != NULL) 2522 initlist_add_neededs(obj->needed_aux_filtees, list); 2523 2524 /* Add the object to the init list. */ 2525 objlist_push_tail(list, obj); 2526 2527 /* Add the object to the global fini list in the reverse order. */ 2528 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2529 && !obj->on_fini_list) { 2530 objlist_push_head(&list_fini, obj); 2531 obj->on_fini_list = true; 2532 } 2533 } 2534 2535 #ifndef FPTR_TARGET 2536 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2537 #endif 2538 2539 static void 2540 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2541 { 2542 Needed_Entry *needed, *needed1; 2543 2544 for (needed = n; needed != NULL; needed = needed->next) { 2545 if (needed->obj != NULL) { 2546 dlclose_locked(needed->obj, lockstate); 2547 needed->obj = NULL; 2548 } 2549 } 2550 for (needed = n; needed != NULL; needed = needed1) { 2551 needed1 = needed->next; 2552 free(needed); 2553 } 2554 } 2555 2556 static void 2557 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2558 { 2559 2560 free_needed_filtees(obj->needed_filtees, lockstate); 2561 obj->needed_filtees = NULL; 2562 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2563 obj->needed_aux_filtees = NULL; 2564 obj->filtees_loaded = false; 2565 } 2566 2567 static void 2568 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2569 RtldLockState *lockstate) 2570 { 2571 2572 for (; needed != NULL; needed = needed->next) { 2573 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2574 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2575 RTLD_LOCAL, lockstate); 2576 } 2577 } 2578 2579 static void 2580 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2581 { 2582 2583 lock_restart_for_upgrade(lockstate); 2584 if (!obj->filtees_loaded) { 2585 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2586 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2587 obj->filtees_loaded = true; 2588 } 2589 } 2590 2591 static int 2592 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2593 { 2594 Obj_Entry *obj1; 2595 2596 for (; needed != NULL; needed = needed->next) { 2597 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2598 flags & ~RTLD_LO_NOLOAD); 2599 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2600 return (-1); 2601 } 2602 return (0); 2603 } 2604 2605 /* 2606 * Given a shared object, traverse its list of needed objects, and load 2607 * each of them. Returns 0 on success. Generates an error message and 2608 * returns -1 on failure. 2609 */ 2610 static int 2611 load_needed_objects(Obj_Entry *first, int flags) 2612 { 2613 Obj_Entry *obj; 2614 2615 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2616 if (obj->marker) 2617 continue; 2618 if (process_needed(obj, obj->needed, flags) == -1) 2619 return (-1); 2620 } 2621 return (0); 2622 } 2623 2624 static int 2625 load_preload_objects(const char *penv, bool isfd) 2626 { 2627 Obj_Entry *obj; 2628 const char *name; 2629 size_t len; 2630 char savech, *p, *psave; 2631 int fd; 2632 static const char delim[] = " \t:;"; 2633 2634 if (penv == NULL) 2635 return (0); 2636 2637 p = psave = xstrdup(penv); 2638 p += strspn(p, delim); 2639 while (*p != '\0') { 2640 len = strcspn(p, delim); 2641 2642 savech = p[len]; 2643 p[len] = '\0'; 2644 if (isfd) { 2645 name = NULL; 2646 fd = parse_integer(p); 2647 if (fd == -1) { 2648 free(psave); 2649 return (-1); 2650 } 2651 } else { 2652 name = p; 2653 fd = -1; 2654 } 2655 2656 obj = load_object(name, fd, NULL, 0); 2657 if (obj == NULL) { 2658 free(psave); 2659 return (-1); /* XXX - cleanup */ 2660 } 2661 obj->z_interpose = true; 2662 p[len] = savech; 2663 p += len; 2664 p += strspn(p, delim); 2665 } 2666 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2667 2668 free(psave); 2669 return (0); 2670 } 2671 2672 static const char * 2673 printable_path(const char *path) 2674 { 2675 2676 return (path == NULL ? "<unknown>" : path); 2677 } 2678 2679 /* 2680 * Load a shared object into memory, if it is not already loaded. The 2681 * object may be specified by name or by user-supplied file descriptor 2682 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2683 * duplicate is. 2684 * 2685 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2686 * on failure. 2687 */ 2688 static Obj_Entry * 2689 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2690 { 2691 Obj_Entry *obj; 2692 int fd; 2693 struct stat sb; 2694 char *path; 2695 2696 fd = -1; 2697 if (name != NULL) { 2698 TAILQ_FOREACH(obj, &obj_list, next) { 2699 if (obj->marker || obj->doomed) 2700 continue; 2701 if (object_match_name(obj, name)) 2702 return (obj); 2703 } 2704 2705 path = find_library(name, refobj, &fd); 2706 if (path == NULL) 2707 return (NULL); 2708 } else 2709 path = NULL; 2710 2711 if (fd >= 0) { 2712 /* 2713 * search_library_pathfds() opens a fresh file descriptor for the 2714 * library, so there is no need to dup(). 2715 */ 2716 } else if (fd_u == -1) { 2717 /* 2718 * If we didn't find a match by pathname, or the name is not 2719 * supplied, open the file and check again by device and inode. 2720 * This avoids false mismatches caused by multiple links or ".." 2721 * in pathnames. 2722 * 2723 * To avoid a race, we open the file and use fstat() rather than 2724 * using stat(). 2725 */ 2726 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2727 _rtld_error("Cannot open \"%s\"", path); 2728 free(path); 2729 return (NULL); 2730 } 2731 } else { 2732 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2733 if (fd == -1) { 2734 _rtld_error("Cannot dup fd"); 2735 free(path); 2736 return (NULL); 2737 } 2738 } 2739 if (fstat(fd, &sb) == -1) { 2740 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2741 close(fd); 2742 free(path); 2743 return (NULL); 2744 } 2745 TAILQ_FOREACH(obj, &obj_list, next) { 2746 if (obj->marker || obj->doomed) 2747 continue; 2748 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2749 break; 2750 } 2751 if (obj != NULL && name != NULL) { 2752 object_add_name(obj, name); 2753 free(path); 2754 close(fd); 2755 return (obj); 2756 } 2757 if (flags & RTLD_LO_NOLOAD) { 2758 free(path); 2759 close(fd); 2760 return (NULL); 2761 } 2762 2763 /* First use of this object, so we must map it in */ 2764 obj = do_load_object(fd, name, path, &sb, flags); 2765 if (obj == NULL) 2766 free(path); 2767 close(fd); 2768 2769 return (obj); 2770 } 2771 2772 static Obj_Entry * 2773 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2774 int flags) 2775 { 2776 Obj_Entry *obj; 2777 struct statfs fs; 2778 2779 /* 2780 * First, make sure that environment variables haven't been 2781 * used to circumvent the noexec flag on a filesystem. 2782 * We ignore fstatfs(2) failures, since fd might reference 2783 * not a file, e.g. shmfd. 2784 */ 2785 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2786 (fs.f_flags & MNT_NOEXEC) != 0) { 2787 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2788 return (NULL); 2789 } 2790 2791 dbg("loading \"%s\"", printable_path(path)); 2792 obj = map_object(fd, printable_path(path), sbp); 2793 if (obj == NULL) 2794 return (NULL); 2795 2796 /* 2797 * If DT_SONAME is present in the object, digest_dynamic2 already 2798 * added it to the object names. 2799 */ 2800 if (name != NULL) 2801 object_add_name(obj, name); 2802 obj->path = path; 2803 if (!digest_dynamic(obj, 0)) 2804 goto errp; 2805 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2806 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2807 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2808 dbg("refusing to load PIE executable \"%s\"", obj->path); 2809 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2810 goto errp; 2811 } 2812 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2813 RTLD_LO_DLOPEN) { 2814 dbg("refusing to load non-loadable \"%s\"", obj->path); 2815 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2816 goto errp; 2817 } 2818 2819 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2820 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2821 obj_count++; 2822 obj_loads++; 2823 linkmap_add(obj); /* for GDB & dlinfo() */ 2824 max_stack_flags |= obj->stack_flags; 2825 2826 dbg(" %p .. %p: %s", obj->mapbase, 2827 obj->mapbase + obj->mapsize - 1, obj->path); 2828 if (obj->textrel) 2829 dbg(" WARNING: %s has impure text", obj->path); 2830 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2831 obj->path); 2832 2833 return (obj); 2834 2835 errp: 2836 munmap(obj->mapbase, obj->mapsize); 2837 obj_free(obj); 2838 return (NULL); 2839 } 2840 2841 static int 2842 load_kpreload(const void *addr) 2843 { 2844 Obj_Entry *obj; 2845 const Elf_Ehdr *ehdr; 2846 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2847 static const char kname[] = "[vdso]"; 2848 2849 ehdr = addr; 2850 if (!check_elf_headers(ehdr, "kpreload")) 2851 return (-1); 2852 obj = obj_new(); 2853 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2854 obj->phdr = phdr; 2855 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2856 phlimit = phdr + ehdr->e_phnum; 2857 seg0 = segn = NULL; 2858 2859 for (; phdr < phlimit; phdr++) { 2860 switch (phdr->p_type) { 2861 case PT_DYNAMIC: 2862 phdyn = phdr; 2863 break; 2864 case PT_GNU_STACK: 2865 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2866 obj->stack_flags = phdr->p_flags; 2867 break; 2868 case PT_LOAD: 2869 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2870 seg0 = phdr; 2871 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2872 phdr->p_vaddr + phdr->p_memsz) 2873 segn = phdr; 2874 break; 2875 } 2876 } 2877 2878 obj->mapbase = __DECONST(caddr_t, addr); 2879 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2880 obj->vaddrbase = 0; 2881 obj->relocbase = obj->mapbase; 2882 2883 object_add_name(obj, kname); 2884 obj->path = xstrdup(kname); 2885 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2886 2887 if (!digest_dynamic(obj, 0)) { 2888 obj_free(obj); 2889 return (-1); 2890 } 2891 2892 /* 2893 * We assume that kernel-preloaded object does not need 2894 * relocation. It is currently written into read-only page, 2895 * handling relocations would mean we need to allocate at 2896 * least one additional page per AS. 2897 */ 2898 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2899 obj->path, obj->mapbase, obj->phdr, seg0, 2900 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2901 2902 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2903 obj_count++; 2904 obj_loads++; 2905 linkmap_add(obj); /* for GDB & dlinfo() */ 2906 max_stack_flags |= obj->stack_flags; 2907 2908 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2909 return (0); 2910 } 2911 2912 Obj_Entry * 2913 obj_from_addr(const void *addr) 2914 { 2915 Obj_Entry *obj; 2916 2917 TAILQ_FOREACH(obj, &obj_list, next) { 2918 if (obj->marker) 2919 continue; 2920 if (addr < (void *) obj->mapbase) 2921 continue; 2922 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2923 return obj; 2924 } 2925 return (NULL); 2926 } 2927 2928 static void 2929 preinit_main(void) 2930 { 2931 Elf_Addr *preinit_addr; 2932 int index; 2933 2934 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2935 if (preinit_addr == NULL) 2936 return; 2937 2938 for (index = 0; index < obj_main->preinit_array_num; index++) { 2939 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2940 dbg("calling preinit function for %s at %p", obj_main->path, 2941 (void *)preinit_addr[index]); 2942 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2943 0, 0, obj_main->path); 2944 call_init_pointer(obj_main, preinit_addr[index]); 2945 } 2946 } 2947 } 2948 2949 /* 2950 * Call the finalization functions for each of the objects in "list" 2951 * belonging to the DAG of "root" and referenced once. If NULL "root" 2952 * is specified, every finalization function will be called regardless 2953 * of the reference count and the list elements won't be freed. All of 2954 * the objects are expected to have non-NULL fini functions. 2955 */ 2956 static void 2957 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2958 { 2959 Objlist_Entry *elm; 2960 struct dlerror_save *saved_msg; 2961 Elf_Addr *fini_addr; 2962 int index; 2963 2964 assert(root == NULL || root->refcount == 1); 2965 2966 if (root != NULL) 2967 root->doomed = true; 2968 2969 /* 2970 * Preserve the current error message since a fini function might 2971 * call into the dynamic linker and overwrite it. 2972 */ 2973 saved_msg = errmsg_save(); 2974 do { 2975 STAILQ_FOREACH(elm, list, link) { 2976 if (root != NULL && (elm->obj->refcount != 1 || 2977 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2978 continue; 2979 /* Remove object from fini list to prevent recursive invocation. */ 2980 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2981 /* Ensure that new references cannot be acquired. */ 2982 elm->obj->doomed = true; 2983 2984 hold_object(elm->obj); 2985 lock_release(rtld_bind_lock, lockstate); 2986 /* 2987 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2988 * When this happens, DT_FINI_ARRAY is processed first. 2989 */ 2990 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2991 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2992 for (index = elm->obj->fini_array_num - 1; index >= 0; 2993 index--) { 2994 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2995 dbg("calling fini function for %s at %p", 2996 elm->obj->path, (void *)fini_addr[index]); 2997 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2998 (void *)fini_addr[index], 0, 0, elm->obj->path); 2999 call_initfini_pointer(elm->obj, fini_addr[index]); 3000 } 3001 } 3002 } 3003 if (elm->obj->fini != (Elf_Addr)NULL) { 3004 dbg("calling fini function for %s at %p", elm->obj->path, 3005 (void *)elm->obj->fini); 3006 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3007 0, 0, elm->obj->path); 3008 call_initfini_pointer(elm->obj, elm->obj->fini); 3009 } 3010 wlock_acquire(rtld_bind_lock, lockstate); 3011 unhold_object(elm->obj); 3012 /* No need to free anything if process is going down. */ 3013 if (root != NULL) 3014 free(elm); 3015 /* 3016 * We must restart the list traversal after every fini call 3017 * because a dlclose() call from the fini function or from 3018 * another thread might have modified the reference counts. 3019 */ 3020 break; 3021 } 3022 } while (elm != NULL); 3023 errmsg_restore(saved_msg); 3024 } 3025 3026 /* 3027 * Call the initialization functions for each of the objects in 3028 * "list". All of the objects are expected to have non-NULL init 3029 * functions. 3030 */ 3031 static void 3032 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3033 { 3034 Objlist_Entry *elm; 3035 Obj_Entry *obj; 3036 struct dlerror_save *saved_msg; 3037 Elf_Addr *init_addr; 3038 void (*reg)(void (*)(void)); 3039 int index; 3040 3041 /* 3042 * Clean init_scanned flag so that objects can be rechecked and 3043 * possibly initialized earlier if any of vectors called below 3044 * cause the change by using dlopen. 3045 */ 3046 TAILQ_FOREACH(obj, &obj_list, next) { 3047 if (obj->marker) 3048 continue; 3049 obj->init_scanned = false; 3050 } 3051 3052 /* 3053 * Preserve the current error message since an init function might 3054 * call into the dynamic linker and overwrite it. 3055 */ 3056 saved_msg = errmsg_save(); 3057 STAILQ_FOREACH(elm, list, link) { 3058 if (elm->obj->init_done) /* Initialized early. */ 3059 continue; 3060 /* 3061 * Race: other thread might try to use this object before current 3062 * one completes the initialization. Not much can be done here 3063 * without better locking. 3064 */ 3065 elm->obj->init_done = true; 3066 hold_object(elm->obj); 3067 reg = NULL; 3068 if (elm->obj == obj_main && obj_main->crt_no_init) { 3069 reg = (void (*)(void (*)(void)))get_program_var_addr( 3070 "__libc_atexit", lockstate); 3071 } 3072 lock_release(rtld_bind_lock, lockstate); 3073 if (reg != NULL) { 3074 reg(rtld_exit); 3075 rtld_exit_ptr = rtld_nop_exit; 3076 } 3077 3078 /* 3079 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3080 * When this happens, DT_INIT is processed first. 3081 */ 3082 if (elm->obj->init != (Elf_Addr)NULL) { 3083 dbg("calling init function for %s at %p", elm->obj->path, 3084 (void *)elm->obj->init); 3085 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3086 0, 0, elm->obj->path); 3087 call_init_pointer(elm->obj, elm->obj->init); 3088 } 3089 init_addr = (Elf_Addr *)elm->obj->init_array; 3090 if (init_addr != NULL) { 3091 for (index = 0; index < elm->obj->init_array_num; index++) { 3092 if (init_addr[index] != 0 && init_addr[index] != 1) { 3093 dbg("calling init function for %s at %p", elm->obj->path, 3094 (void *)init_addr[index]); 3095 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3096 (void *)init_addr[index], 0, 0, elm->obj->path); 3097 call_init_pointer(elm->obj, init_addr[index]); 3098 } 3099 } 3100 } 3101 wlock_acquire(rtld_bind_lock, lockstate); 3102 unhold_object(elm->obj); 3103 } 3104 errmsg_restore(saved_msg); 3105 } 3106 3107 static void 3108 objlist_clear(Objlist *list) 3109 { 3110 Objlist_Entry *elm; 3111 3112 while (!STAILQ_EMPTY(list)) { 3113 elm = STAILQ_FIRST(list); 3114 STAILQ_REMOVE_HEAD(list, link); 3115 free(elm); 3116 } 3117 } 3118 3119 static Objlist_Entry * 3120 objlist_find(Objlist *list, const Obj_Entry *obj) 3121 { 3122 Objlist_Entry *elm; 3123 3124 STAILQ_FOREACH(elm, list, link) 3125 if (elm->obj == obj) 3126 return elm; 3127 return (NULL); 3128 } 3129 3130 static void 3131 objlist_init(Objlist *list) 3132 { 3133 STAILQ_INIT(list); 3134 } 3135 3136 static void 3137 objlist_push_head(Objlist *list, Obj_Entry *obj) 3138 { 3139 Objlist_Entry *elm; 3140 3141 elm = NEW(Objlist_Entry); 3142 elm->obj = obj; 3143 STAILQ_INSERT_HEAD(list, elm, link); 3144 } 3145 3146 static void 3147 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3148 { 3149 Objlist_Entry *elm; 3150 3151 elm = NEW(Objlist_Entry); 3152 elm->obj = obj; 3153 STAILQ_INSERT_TAIL(list, elm, link); 3154 } 3155 3156 static void 3157 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3158 { 3159 Objlist_Entry *elm, *listelm; 3160 3161 STAILQ_FOREACH(listelm, list, link) { 3162 if (listelm->obj == listobj) 3163 break; 3164 } 3165 elm = NEW(Objlist_Entry); 3166 elm->obj = obj; 3167 if (listelm != NULL) 3168 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3169 else 3170 STAILQ_INSERT_TAIL(list, elm, link); 3171 } 3172 3173 static void 3174 objlist_remove(Objlist *list, Obj_Entry *obj) 3175 { 3176 Objlist_Entry *elm; 3177 3178 if ((elm = objlist_find(list, obj)) != NULL) { 3179 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3180 free(elm); 3181 } 3182 } 3183 3184 /* 3185 * Relocate dag rooted in the specified object. 3186 * Returns 0 on success, or -1 on failure. 3187 */ 3188 3189 static int 3190 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3191 int flags, RtldLockState *lockstate) 3192 { 3193 Objlist_Entry *elm; 3194 int error; 3195 3196 error = 0; 3197 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3198 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3199 lockstate); 3200 if (error == -1) 3201 break; 3202 } 3203 return (error); 3204 } 3205 3206 /* 3207 * Prepare for, or clean after, relocating an object marked with 3208 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3209 * segments are remapped read-write. After relocations are done, the 3210 * segment's permissions are returned back to the modes specified in 3211 * the phdrs. If any relocation happened, or always for wired 3212 * program, COW is triggered. 3213 */ 3214 static int 3215 reloc_textrel_prot(Obj_Entry *obj, bool before) 3216 { 3217 const Elf_Phdr *ph; 3218 void *base; 3219 size_t l, sz; 3220 int prot; 3221 3222 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3223 l--, ph++) { 3224 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3225 continue; 3226 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3227 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3228 rtld_trunc_page(ph->p_vaddr); 3229 prot = before ? (PROT_READ | PROT_WRITE) : 3230 convert_prot(ph->p_flags); 3231 if (mprotect(base, sz, prot) == -1) { 3232 _rtld_error("%s: Cannot write-%sable text segment: %s", 3233 obj->path, before ? "en" : "dis", 3234 rtld_strerror(errno)); 3235 return (-1); 3236 } 3237 } 3238 return (0); 3239 } 3240 3241 /* Process RELR relative relocations. */ 3242 static void 3243 reloc_relr(Obj_Entry *obj) 3244 { 3245 const Elf_Relr *relr, *relrlim; 3246 Elf_Addr *where; 3247 3248 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3249 for (relr = obj->relr; relr < relrlim; relr++) { 3250 Elf_Relr entry = *relr; 3251 3252 if ((entry & 1) == 0) { 3253 where = (Elf_Addr *)(obj->relocbase + entry); 3254 *where++ += (Elf_Addr)obj->relocbase; 3255 } else { 3256 for (long i = 0; (entry >>= 1) != 0; i++) 3257 if ((entry & 1) != 0) 3258 where[i] += (Elf_Addr)obj->relocbase; 3259 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3260 } 3261 } 3262 } 3263 3264 /* 3265 * Relocate single object. 3266 * Returns 0 on success, or -1 on failure. 3267 */ 3268 static int 3269 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3270 int flags, RtldLockState *lockstate) 3271 { 3272 3273 if (obj->relocated) 3274 return (0); 3275 obj->relocated = true; 3276 if (obj != rtldobj) 3277 dbg("relocating \"%s\"", obj->path); 3278 3279 if (obj->symtab == NULL || obj->strtab == NULL || 3280 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3281 dbg("object %s has no run-time symbol table", obj->path); 3282 3283 /* There are relocations to the write-protected text segment. */ 3284 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3285 return (-1); 3286 3287 /* Process the non-PLT non-IFUNC relocations. */ 3288 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3289 return (-1); 3290 reloc_relr(obj); 3291 3292 /* Re-protected the text segment. */ 3293 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3294 return (-1); 3295 3296 /* Set the special PLT or GOT entries. */ 3297 init_pltgot(obj); 3298 3299 /* Process the PLT relocations. */ 3300 if (reloc_plt(obj, flags, lockstate) == -1) 3301 return (-1); 3302 /* Relocate the jump slots if we are doing immediate binding. */ 3303 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3304 lockstate) == -1) 3305 return (-1); 3306 3307 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3308 return (-1); 3309 3310 /* 3311 * Set up the magic number and version in the Obj_Entry. These 3312 * were checked in the crt1.o from the original ElfKit, so we 3313 * set them for backward compatibility. 3314 */ 3315 obj->magic = RTLD_MAGIC; 3316 obj->version = RTLD_VERSION; 3317 3318 return (0); 3319 } 3320 3321 /* 3322 * Relocate newly-loaded shared objects. The argument is a pointer to 3323 * the Obj_Entry for the first such object. All objects from the first 3324 * to the end of the list of objects are relocated. Returns 0 on success, 3325 * or -1 on failure. 3326 */ 3327 static int 3328 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3329 int flags, RtldLockState *lockstate) 3330 { 3331 Obj_Entry *obj; 3332 int error; 3333 3334 for (error = 0, obj = first; obj != NULL; 3335 obj = TAILQ_NEXT(obj, next)) { 3336 if (obj->marker) 3337 continue; 3338 error = relocate_object(obj, bind_now, rtldobj, flags, 3339 lockstate); 3340 if (error == -1) 3341 break; 3342 } 3343 return (error); 3344 } 3345 3346 /* 3347 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3348 * referencing STT_GNU_IFUNC symbols is postponed till the other 3349 * relocations are done. The indirect functions specified as 3350 * ifunc are allowed to call other symbols, so we need to have 3351 * objects relocated before asking for resolution from indirects. 3352 * 3353 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3354 * instead of the usual lazy handling of PLT slots. It is 3355 * consistent with how GNU does it. 3356 */ 3357 static int 3358 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3359 RtldLockState *lockstate) 3360 { 3361 3362 if (obj->ifuncs_resolved) 3363 return (0); 3364 obj->ifuncs_resolved = true; 3365 if (!obj->irelative && !obj->irelative_nonplt && 3366 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3367 !obj->non_plt_gnu_ifunc) 3368 return (0); 3369 if (obj_disable_relro(obj) == -1 || 3370 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3371 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3372 lockstate) == -1) || 3373 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3374 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3375 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3376 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3377 obj_enforce_relro(obj) == -1) 3378 return (-1); 3379 return (0); 3380 } 3381 3382 static int 3383 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3384 RtldLockState *lockstate) 3385 { 3386 Objlist_Entry *elm; 3387 Obj_Entry *obj; 3388 3389 STAILQ_FOREACH(elm, list, link) { 3390 obj = elm->obj; 3391 if (obj->marker) 3392 continue; 3393 if (resolve_object_ifunc(obj, bind_now, flags, 3394 lockstate) == -1) 3395 return (-1); 3396 } 3397 return (0); 3398 } 3399 3400 /* 3401 * Cleanup procedure. It will be called (by the atexit mechanism) just 3402 * before the process exits. 3403 */ 3404 static void 3405 rtld_exit(void) 3406 { 3407 RtldLockState lockstate; 3408 3409 wlock_acquire(rtld_bind_lock, &lockstate); 3410 dbg("rtld_exit()"); 3411 objlist_call_fini(&list_fini, NULL, &lockstate); 3412 /* No need to remove the items from the list, since we are exiting. */ 3413 if (!libmap_disable) 3414 lm_fini(); 3415 lock_release(rtld_bind_lock, &lockstate); 3416 } 3417 3418 static void 3419 rtld_nop_exit(void) 3420 { 3421 } 3422 3423 /* 3424 * Iterate over a search path, translate each element, and invoke the 3425 * callback on the result. 3426 */ 3427 static void * 3428 path_enumerate(const char *path, path_enum_proc callback, 3429 const char *refobj_path, void *arg) 3430 { 3431 const char *trans; 3432 if (path == NULL) 3433 return (NULL); 3434 3435 path += strspn(path, ":;"); 3436 while (*path != '\0') { 3437 size_t len; 3438 char *res; 3439 3440 len = strcspn(path, ":;"); 3441 trans = lm_findn(refobj_path, path, len); 3442 if (trans) 3443 res = callback(trans, strlen(trans), arg); 3444 else 3445 res = callback(path, len, arg); 3446 3447 if (res != NULL) 3448 return (res); 3449 3450 path += len; 3451 path += strspn(path, ":;"); 3452 } 3453 3454 return (NULL); 3455 } 3456 3457 struct try_library_args { 3458 const char *name; 3459 size_t namelen; 3460 char *buffer; 3461 size_t buflen; 3462 int fd; 3463 }; 3464 3465 static void * 3466 try_library_path(const char *dir, size_t dirlen, void *param) 3467 { 3468 struct try_library_args *arg; 3469 int fd; 3470 3471 arg = param; 3472 if (*dir == '/' || trust) { 3473 char *pathname; 3474 3475 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3476 return (NULL); 3477 3478 pathname = arg->buffer; 3479 strncpy(pathname, dir, dirlen); 3480 pathname[dirlen] = '/'; 3481 strcpy(pathname + dirlen + 1, arg->name); 3482 3483 dbg(" Trying \"%s\"", pathname); 3484 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3485 if (fd >= 0) { 3486 dbg(" Opened \"%s\", fd %d", pathname, fd); 3487 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3488 strcpy(pathname, arg->buffer); 3489 arg->fd = fd; 3490 return (pathname); 3491 } else { 3492 dbg(" Failed to open \"%s\": %s", 3493 pathname, rtld_strerror(errno)); 3494 } 3495 } 3496 return (NULL); 3497 } 3498 3499 static char * 3500 search_library_path(const char *name, const char *path, 3501 const char *refobj_path, int *fdp) 3502 { 3503 char *p; 3504 struct try_library_args arg; 3505 3506 if (path == NULL) 3507 return (NULL); 3508 3509 arg.name = name; 3510 arg.namelen = strlen(name); 3511 arg.buffer = xmalloc(PATH_MAX); 3512 arg.buflen = PATH_MAX; 3513 arg.fd = -1; 3514 3515 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3516 *fdp = arg.fd; 3517 3518 free(arg.buffer); 3519 3520 return (p); 3521 } 3522 3523 3524 /* 3525 * Finds the library with the given name using the directory descriptors 3526 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3527 * 3528 * Returns a freshly-opened close-on-exec file descriptor for the library, 3529 * or -1 if the library cannot be found. 3530 */ 3531 static char * 3532 search_library_pathfds(const char *name, const char *path, int *fdp) 3533 { 3534 char *envcopy, *fdstr, *found, *last_token; 3535 size_t len; 3536 int dirfd, fd; 3537 3538 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3539 3540 /* Don't load from user-specified libdirs into setuid binaries. */ 3541 if (!trust) 3542 return (NULL); 3543 3544 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3545 if (path == NULL) 3546 return (NULL); 3547 3548 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3549 if (name[0] == '/') { 3550 dbg("Absolute path (%s) passed to %s", name, __func__); 3551 return (NULL); 3552 } 3553 3554 /* 3555 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3556 * copy of the path, as strtok_r rewrites separator tokens 3557 * with '\0'. 3558 */ 3559 found = NULL; 3560 envcopy = xstrdup(path); 3561 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3562 fdstr = strtok_r(NULL, ":", &last_token)) { 3563 dirfd = parse_integer(fdstr); 3564 if (dirfd < 0) { 3565 _rtld_error("failed to parse directory FD: '%s'", 3566 fdstr); 3567 break; 3568 } 3569 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3570 if (fd >= 0) { 3571 *fdp = fd; 3572 len = strlen(fdstr) + strlen(name) + 3; 3573 found = xmalloc(len); 3574 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3575 _rtld_error("error generating '%d/%s'", 3576 dirfd, name); 3577 rtld_die(); 3578 } 3579 dbg("open('%s') => %d", found, fd); 3580 break; 3581 } 3582 } 3583 free(envcopy); 3584 3585 return (found); 3586 } 3587 3588 3589 int 3590 dlclose(void *handle) 3591 { 3592 RtldLockState lockstate; 3593 int error; 3594 3595 wlock_acquire(rtld_bind_lock, &lockstate); 3596 error = dlclose_locked(handle, &lockstate); 3597 lock_release(rtld_bind_lock, &lockstate); 3598 return (error); 3599 } 3600 3601 static int 3602 dlclose_locked(void *handle, RtldLockState *lockstate) 3603 { 3604 Obj_Entry *root; 3605 3606 root = dlcheck(handle); 3607 if (root == NULL) 3608 return (-1); 3609 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3610 root->path); 3611 3612 /* Unreference the object and its dependencies. */ 3613 root->dl_refcount--; 3614 3615 if (root->refcount == 1) { 3616 /* 3617 * The object will be no longer referenced, so we must unload it. 3618 * First, call the fini functions. 3619 */ 3620 objlist_call_fini(&list_fini, root, lockstate); 3621 3622 unref_dag(root); 3623 3624 /* Finish cleaning up the newly-unreferenced objects. */ 3625 GDB_STATE(RT_DELETE,&root->linkmap); 3626 unload_object(root, lockstate); 3627 GDB_STATE(RT_CONSISTENT,NULL); 3628 } else 3629 unref_dag(root); 3630 3631 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3632 return (0); 3633 } 3634 3635 char * 3636 dlerror(void) 3637 { 3638 if (*(lockinfo.dlerror_seen()) != 0) 3639 return (NULL); 3640 *lockinfo.dlerror_seen() = 1; 3641 return (lockinfo.dlerror_loc()); 3642 } 3643 3644 /* 3645 * This function is deprecated and has no effect. 3646 */ 3647 void 3648 dllockinit(void *context, 3649 void *(*_lock_create)(void *context) __unused, 3650 void (*_rlock_acquire)(void *lock) __unused, 3651 void (*_wlock_acquire)(void *lock) __unused, 3652 void (*_lock_release)(void *lock) __unused, 3653 void (*_lock_destroy)(void *lock) __unused, 3654 void (*context_destroy)(void *context)) 3655 { 3656 static void *cur_context; 3657 static void (*cur_context_destroy)(void *); 3658 3659 /* Just destroy the context from the previous call, if necessary. */ 3660 if (cur_context_destroy != NULL) 3661 cur_context_destroy(cur_context); 3662 cur_context = context; 3663 cur_context_destroy = context_destroy; 3664 } 3665 3666 void * 3667 dlopen(const char *name, int mode) 3668 { 3669 3670 return (rtld_dlopen(name, -1, mode)); 3671 } 3672 3673 void * 3674 fdlopen(int fd, int mode) 3675 { 3676 3677 return (rtld_dlopen(NULL, fd, mode)); 3678 } 3679 3680 static void * 3681 rtld_dlopen(const char *name, int fd, int mode) 3682 { 3683 RtldLockState lockstate; 3684 int lo_flags; 3685 3686 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3687 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3688 if (ld_tracing != NULL) { 3689 rlock_acquire(rtld_bind_lock, &lockstate); 3690 if (sigsetjmp(lockstate.env, 0) != 0) 3691 lock_upgrade(rtld_bind_lock, &lockstate); 3692 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3693 lock_release(rtld_bind_lock, &lockstate); 3694 } 3695 lo_flags = RTLD_LO_DLOPEN; 3696 if (mode & RTLD_NODELETE) 3697 lo_flags |= RTLD_LO_NODELETE; 3698 if (mode & RTLD_NOLOAD) 3699 lo_flags |= RTLD_LO_NOLOAD; 3700 if (mode & RTLD_DEEPBIND) 3701 lo_flags |= RTLD_LO_DEEPBIND; 3702 if (ld_tracing != NULL) 3703 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3704 3705 return (dlopen_object(name, fd, obj_main, lo_flags, 3706 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3707 } 3708 3709 static void 3710 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3711 { 3712 3713 obj->dl_refcount--; 3714 unref_dag(obj); 3715 if (obj->refcount == 0) 3716 unload_object(obj, lockstate); 3717 } 3718 3719 static Obj_Entry * 3720 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3721 int mode, RtldLockState *lockstate) 3722 { 3723 Obj_Entry *old_obj_tail; 3724 Obj_Entry *obj; 3725 Objlist initlist; 3726 RtldLockState mlockstate; 3727 int result; 3728 3729 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3730 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3731 refobj->path, lo_flags, mode); 3732 objlist_init(&initlist); 3733 3734 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3735 wlock_acquire(rtld_bind_lock, &mlockstate); 3736 lockstate = &mlockstate; 3737 } 3738 GDB_STATE(RT_ADD,NULL); 3739 3740 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3741 obj = NULL; 3742 if (name == NULL && fd == -1) { 3743 obj = obj_main; 3744 obj->refcount++; 3745 } else { 3746 obj = load_object(name, fd, refobj, lo_flags); 3747 } 3748 3749 if (obj) { 3750 obj->dl_refcount++; 3751 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3752 objlist_push_tail(&list_global, obj); 3753 if (globallist_next(old_obj_tail) != NULL) { 3754 /* We loaded something new. */ 3755 assert(globallist_next(old_obj_tail) == obj); 3756 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3757 obj->symbolic = true; 3758 result = 0; 3759 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3760 obj->static_tls && !allocate_tls_offset(obj)) { 3761 _rtld_error("%s: No space available " 3762 "for static Thread Local Storage", obj->path); 3763 result = -1; 3764 } 3765 if (result != -1) 3766 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3767 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3768 init_dag(obj); 3769 ref_dag(obj); 3770 if (result != -1) 3771 result = rtld_verify_versions(&obj->dagmembers); 3772 if (result != -1 && ld_tracing) 3773 goto trace; 3774 if (result == -1 || relocate_object_dag(obj, 3775 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3776 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3777 lockstate) == -1) { 3778 dlopen_cleanup(obj, lockstate); 3779 obj = NULL; 3780 } else if (lo_flags & RTLD_LO_EARLY) { 3781 /* 3782 * Do not call the init functions for early loaded 3783 * filtees. The image is still not initialized enough 3784 * for them to work. 3785 * 3786 * Our object is found by the global object list and 3787 * will be ordered among all init calls done right 3788 * before transferring control to main. 3789 */ 3790 } else { 3791 /* Make list of init functions to call. */ 3792 initlist_add_objects(obj, obj, &initlist); 3793 } 3794 /* 3795 * Process all no_delete or global objects here, given 3796 * them own DAGs to prevent their dependencies from being 3797 * unloaded. This has to be done after we have loaded all 3798 * of the dependencies, so that we do not miss any. 3799 */ 3800 if (obj != NULL) 3801 process_z(obj); 3802 } else { 3803 /* 3804 * Bump the reference counts for objects on this DAG. If 3805 * this is the first dlopen() call for the object that was 3806 * already loaded as a dependency, initialize the dag 3807 * starting at it. 3808 */ 3809 init_dag(obj); 3810 ref_dag(obj); 3811 3812 if ((lo_flags & RTLD_LO_TRACE) != 0) 3813 goto trace; 3814 } 3815 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3816 obj->z_nodelete) && !obj->ref_nodel) { 3817 dbg("obj %s nodelete", obj->path); 3818 ref_dag(obj); 3819 obj->z_nodelete = obj->ref_nodel = true; 3820 } 3821 } 3822 3823 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3824 name); 3825 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3826 3827 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3828 map_stacks_exec(lockstate); 3829 if (obj != NULL) 3830 distribute_static_tls(&initlist, lockstate); 3831 } 3832 3833 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3834 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3835 lockstate) == -1) { 3836 objlist_clear(&initlist); 3837 dlopen_cleanup(obj, lockstate); 3838 if (lockstate == &mlockstate) 3839 lock_release(rtld_bind_lock, lockstate); 3840 return (NULL); 3841 } 3842 3843 if (!(lo_flags & RTLD_LO_EARLY)) { 3844 /* Call the init functions. */ 3845 objlist_call_init(&initlist, lockstate); 3846 } 3847 objlist_clear(&initlist); 3848 if (lockstate == &mlockstate) 3849 lock_release(rtld_bind_lock, lockstate); 3850 return (obj); 3851 trace: 3852 trace_loaded_objects(obj, false); 3853 if (lockstate == &mlockstate) 3854 lock_release(rtld_bind_lock, lockstate); 3855 exit(0); 3856 } 3857 3858 static void * 3859 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3860 int flags) 3861 { 3862 DoneList donelist; 3863 const Obj_Entry *obj, *defobj; 3864 const Elf_Sym *def; 3865 SymLook req; 3866 RtldLockState lockstate; 3867 tls_index ti; 3868 void *sym; 3869 int res; 3870 3871 def = NULL; 3872 defobj = NULL; 3873 symlook_init(&req, name); 3874 req.ventry = ve; 3875 req.flags = flags | SYMLOOK_IN_PLT; 3876 req.lockstate = &lockstate; 3877 3878 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3879 rlock_acquire(rtld_bind_lock, &lockstate); 3880 if (sigsetjmp(lockstate.env, 0) != 0) 3881 lock_upgrade(rtld_bind_lock, &lockstate); 3882 if (handle == NULL || handle == RTLD_NEXT || 3883 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3884 3885 if ((obj = obj_from_addr(retaddr)) == NULL) { 3886 _rtld_error("Cannot determine caller's shared object"); 3887 lock_release(rtld_bind_lock, &lockstate); 3888 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3889 return (NULL); 3890 } 3891 if (handle == NULL) { /* Just the caller's shared object. */ 3892 res = symlook_obj(&req, obj); 3893 if (res == 0) { 3894 def = req.sym_out; 3895 defobj = req.defobj_out; 3896 } 3897 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3898 handle == RTLD_SELF) { /* ... caller included */ 3899 if (handle == RTLD_NEXT) 3900 obj = globallist_next(obj); 3901 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3902 if (obj->marker) 3903 continue; 3904 res = symlook_obj(&req, obj); 3905 if (res == 0) { 3906 if (def == NULL || (ld_dynamic_weak && 3907 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3908 def = req.sym_out; 3909 defobj = req.defobj_out; 3910 if (!ld_dynamic_weak || 3911 ELF_ST_BIND(def->st_info) != STB_WEAK) 3912 break; 3913 } 3914 } 3915 } 3916 /* 3917 * Search the dynamic linker itself, and possibly resolve the 3918 * symbol from there. This is how the application links to 3919 * dynamic linker services such as dlopen. 3920 * Note that we ignore ld_dynamic_weak == false case, 3921 * always overriding weak symbols by rtld definitions. 3922 */ 3923 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3924 res = symlook_obj(&req, &obj_rtld); 3925 if (res == 0) { 3926 def = req.sym_out; 3927 defobj = req.defobj_out; 3928 } 3929 } 3930 } else { 3931 assert(handle == RTLD_DEFAULT); 3932 res = symlook_default(&req, obj); 3933 if (res == 0) { 3934 defobj = req.defobj_out; 3935 def = req.sym_out; 3936 } 3937 } 3938 } else { 3939 if ((obj = dlcheck(handle)) == NULL) { 3940 lock_release(rtld_bind_lock, &lockstate); 3941 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3942 return (NULL); 3943 } 3944 3945 donelist_init(&donelist); 3946 if (obj->mainprog) { 3947 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3948 res = symlook_global(&req, &donelist); 3949 if (res == 0) { 3950 def = req.sym_out; 3951 defobj = req.defobj_out; 3952 } 3953 /* 3954 * Search the dynamic linker itself, and possibly resolve the 3955 * symbol from there. This is how the application links to 3956 * dynamic linker services such as dlopen. 3957 */ 3958 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3959 res = symlook_obj(&req, &obj_rtld); 3960 if (res == 0) { 3961 def = req.sym_out; 3962 defobj = req.defobj_out; 3963 } 3964 } 3965 } 3966 else { 3967 /* Search the whole DAG rooted at the given object. */ 3968 res = symlook_list(&req, &obj->dagmembers, &donelist); 3969 if (res == 0) { 3970 def = req.sym_out; 3971 defobj = req.defobj_out; 3972 } 3973 } 3974 } 3975 3976 if (def != NULL) { 3977 lock_release(rtld_bind_lock, &lockstate); 3978 3979 /* 3980 * The value required by the caller is derived from the value 3981 * of the symbol. this is simply the relocated value of the 3982 * symbol. 3983 */ 3984 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3985 sym = make_function_pointer(def, defobj); 3986 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3987 sym = rtld_resolve_ifunc(defobj, def); 3988 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3989 ti.ti_module = defobj->tlsindex; 3990 ti.ti_offset = def->st_value; 3991 sym = __tls_get_addr(&ti); 3992 } else 3993 sym = defobj->relocbase + def->st_value; 3994 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3995 return (sym); 3996 } 3997 3998 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3999 ve != NULL ? ve->name : ""); 4000 lock_release(rtld_bind_lock, &lockstate); 4001 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4002 return (NULL); 4003 } 4004 4005 void * 4006 dlsym(void *handle, const char *name) 4007 { 4008 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4009 SYMLOOK_DLSYM)); 4010 } 4011 4012 dlfunc_t 4013 dlfunc(void *handle, const char *name) 4014 { 4015 union { 4016 void *d; 4017 dlfunc_t f; 4018 } rv; 4019 4020 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4021 SYMLOOK_DLSYM); 4022 return (rv.f); 4023 } 4024 4025 void * 4026 dlvsym(void *handle, const char *name, const char *version) 4027 { 4028 Ver_Entry ventry; 4029 4030 ventry.name = version; 4031 ventry.file = NULL; 4032 ventry.hash = elf_hash(version); 4033 ventry.flags= 0; 4034 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4035 SYMLOOK_DLSYM)); 4036 } 4037 4038 int 4039 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4040 { 4041 const Obj_Entry *obj; 4042 RtldLockState lockstate; 4043 4044 rlock_acquire(rtld_bind_lock, &lockstate); 4045 obj = obj_from_addr(addr); 4046 if (obj == NULL) { 4047 _rtld_error("No shared object contains address"); 4048 lock_release(rtld_bind_lock, &lockstate); 4049 return (0); 4050 } 4051 rtld_fill_dl_phdr_info(obj, phdr_info); 4052 lock_release(rtld_bind_lock, &lockstate); 4053 return (1); 4054 } 4055 4056 int 4057 dladdr(const void *addr, Dl_info *info) 4058 { 4059 const Obj_Entry *obj; 4060 const Elf_Sym *def; 4061 void *symbol_addr; 4062 unsigned long symoffset; 4063 RtldLockState lockstate; 4064 4065 rlock_acquire(rtld_bind_lock, &lockstate); 4066 obj = obj_from_addr(addr); 4067 if (obj == NULL) { 4068 _rtld_error("No shared object contains address"); 4069 lock_release(rtld_bind_lock, &lockstate); 4070 return (0); 4071 } 4072 info->dli_fname = obj->path; 4073 info->dli_fbase = obj->mapbase; 4074 info->dli_saddr = (void *)0; 4075 info->dli_sname = NULL; 4076 4077 /* 4078 * Walk the symbol list looking for the symbol whose address is 4079 * closest to the address sent in. 4080 */ 4081 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4082 def = obj->symtab + symoffset; 4083 4084 /* 4085 * For skip the symbol if st_shndx is either SHN_UNDEF or 4086 * SHN_COMMON. 4087 */ 4088 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4089 continue; 4090 4091 /* 4092 * If the symbol is greater than the specified address, or if it 4093 * is further away from addr than the current nearest symbol, 4094 * then reject it. 4095 */ 4096 symbol_addr = obj->relocbase + def->st_value; 4097 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4098 continue; 4099 4100 /* Update our idea of the nearest symbol. */ 4101 info->dli_sname = obj->strtab + def->st_name; 4102 info->dli_saddr = symbol_addr; 4103 4104 /* Exact match? */ 4105 if (info->dli_saddr == addr) 4106 break; 4107 } 4108 lock_release(rtld_bind_lock, &lockstate); 4109 return (1); 4110 } 4111 4112 int 4113 dlinfo(void *handle, int request, void *p) 4114 { 4115 const Obj_Entry *obj; 4116 RtldLockState lockstate; 4117 int error; 4118 4119 rlock_acquire(rtld_bind_lock, &lockstate); 4120 4121 if (handle == NULL || handle == RTLD_SELF) { 4122 void *retaddr; 4123 4124 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4125 if ((obj = obj_from_addr(retaddr)) == NULL) 4126 _rtld_error("Cannot determine caller's shared object"); 4127 } else 4128 obj = dlcheck(handle); 4129 4130 if (obj == NULL) { 4131 lock_release(rtld_bind_lock, &lockstate); 4132 return (-1); 4133 } 4134 4135 error = 0; 4136 switch (request) { 4137 case RTLD_DI_LINKMAP: 4138 *((struct link_map const **)p) = &obj->linkmap; 4139 break; 4140 case RTLD_DI_ORIGIN: 4141 error = rtld_dirname(obj->path, p); 4142 break; 4143 4144 case RTLD_DI_SERINFOSIZE: 4145 case RTLD_DI_SERINFO: 4146 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4147 break; 4148 4149 default: 4150 _rtld_error("Invalid request %d passed to dlinfo()", request); 4151 error = -1; 4152 } 4153 4154 lock_release(rtld_bind_lock, &lockstate); 4155 4156 return (error); 4157 } 4158 4159 static void 4160 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4161 { 4162 uintptr_t **dtvp; 4163 4164 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4165 phdr_info->dlpi_name = obj->path; 4166 phdr_info->dlpi_phdr = obj->phdr; 4167 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4168 phdr_info->dlpi_tls_modid = obj->tlsindex; 4169 dtvp = &_tcb_get()->tcb_dtv; 4170 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4171 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4172 phdr_info->dlpi_adds = obj_loads; 4173 phdr_info->dlpi_subs = obj_loads - obj_count; 4174 } 4175 4176 int 4177 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4178 { 4179 struct dl_phdr_info phdr_info; 4180 Obj_Entry *obj, marker; 4181 RtldLockState bind_lockstate, phdr_lockstate; 4182 int error; 4183 4184 init_marker(&marker); 4185 error = 0; 4186 4187 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4188 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4189 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4190 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4191 rtld_fill_dl_phdr_info(obj, &phdr_info); 4192 hold_object(obj); 4193 lock_release(rtld_bind_lock, &bind_lockstate); 4194 4195 error = callback(&phdr_info, sizeof phdr_info, param); 4196 4197 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4198 unhold_object(obj); 4199 obj = globallist_next(&marker); 4200 TAILQ_REMOVE(&obj_list, &marker, next); 4201 if (error != 0) { 4202 lock_release(rtld_bind_lock, &bind_lockstate); 4203 lock_release(rtld_phdr_lock, &phdr_lockstate); 4204 return (error); 4205 } 4206 } 4207 4208 if (error == 0) { 4209 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4210 lock_release(rtld_bind_lock, &bind_lockstate); 4211 error = callback(&phdr_info, sizeof(phdr_info), param); 4212 } 4213 lock_release(rtld_phdr_lock, &phdr_lockstate); 4214 return (error); 4215 } 4216 4217 static void * 4218 fill_search_info(const char *dir, size_t dirlen, void *param) 4219 { 4220 struct fill_search_info_args *arg; 4221 4222 arg = param; 4223 4224 if (arg->request == RTLD_DI_SERINFOSIZE) { 4225 arg->serinfo->dls_cnt ++; 4226 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4227 } else { 4228 struct dl_serpath *s_entry; 4229 4230 s_entry = arg->serpath; 4231 s_entry->dls_name = arg->strspace; 4232 s_entry->dls_flags = arg->flags; 4233 4234 strncpy(arg->strspace, dir, dirlen); 4235 arg->strspace[dirlen] = '\0'; 4236 4237 arg->strspace += dirlen + 1; 4238 arg->serpath++; 4239 } 4240 4241 return (NULL); 4242 } 4243 4244 static int 4245 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4246 { 4247 struct dl_serinfo _info; 4248 struct fill_search_info_args args; 4249 4250 args.request = RTLD_DI_SERINFOSIZE; 4251 args.serinfo = &_info; 4252 4253 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4254 _info.dls_cnt = 0; 4255 4256 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4257 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4258 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4259 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4260 if (!obj->z_nodeflib) 4261 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4262 4263 4264 if (request == RTLD_DI_SERINFOSIZE) { 4265 info->dls_size = _info.dls_size; 4266 info->dls_cnt = _info.dls_cnt; 4267 return (0); 4268 } 4269 4270 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4271 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4272 return (-1); 4273 } 4274 4275 args.request = RTLD_DI_SERINFO; 4276 args.serinfo = info; 4277 args.serpath = &info->dls_serpath[0]; 4278 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4279 4280 args.flags = LA_SER_RUNPATH; 4281 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4282 return (-1); 4283 4284 args.flags = LA_SER_LIBPATH; 4285 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4286 return (-1); 4287 4288 args.flags = LA_SER_RUNPATH; 4289 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4290 return (-1); 4291 4292 args.flags = LA_SER_CONFIG; 4293 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4294 != NULL) 4295 return (-1); 4296 4297 args.flags = LA_SER_DEFAULT; 4298 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4299 fill_search_info, NULL, &args) != NULL) 4300 return (-1); 4301 return (0); 4302 } 4303 4304 static int 4305 rtld_dirname(const char *path, char *bname) 4306 { 4307 const char *endp; 4308 4309 /* Empty or NULL string gets treated as "." */ 4310 if (path == NULL || *path == '\0') { 4311 bname[0] = '.'; 4312 bname[1] = '\0'; 4313 return (0); 4314 } 4315 4316 /* Strip trailing slashes */ 4317 endp = path + strlen(path) - 1; 4318 while (endp > path && *endp == '/') 4319 endp--; 4320 4321 /* Find the start of the dir */ 4322 while (endp > path && *endp != '/') 4323 endp--; 4324 4325 /* Either the dir is "/" or there are no slashes */ 4326 if (endp == path) { 4327 bname[0] = *endp == '/' ? '/' : '.'; 4328 bname[1] = '\0'; 4329 return (0); 4330 } else { 4331 do { 4332 endp--; 4333 } while (endp > path && *endp == '/'); 4334 } 4335 4336 if (endp - path + 2 > PATH_MAX) 4337 { 4338 _rtld_error("Filename is too long: %s", path); 4339 return(-1); 4340 } 4341 4342 strncpy(bname, path, endp - path + 1); 4343 bname[endp - path + 1] = '\0'; 4344 return (0); 4345 } 4346 4347 static int 4348 rtld_dirname_abs(const char *path, char *base) 4349 { 4350 char *last; 4351 4352 if (realpath(path, base) == NULL) { 4353 _rtld_error("realpath \"%s\" failed (%s)", path, 4354 rtld_strerror(errno)); 4355 return (-1); 4356 } 4357 dbg("%s -> %s", path, base); 4358 last = strrchr(base, '/'); 4359 if (last == NULL) { 4360 _rtld_error("non-abs result from realpath \"%s\"", path); 4361 return (-1); 4362 } 4363 if (last != base) 4364 *last = '\0'; 4365 return (0); 4366 } 4367 4368 static void 4369 linkmap_add(Obj_Entry *obj) 4370 { 4371 struct link_map *l, *prev; 4372 4373 l = &obj->linkmap; 4374 l->l_name = obj->path; 4375 l->l_base = obj->mapbase; 4376 l->l_ld = obj->dynamic; 4377 l->l_addr = obj->relocbase; 4378 4379 if (r_debug.r_map == NULL) { 4380 r_debug.r_map = l; 4381 return; 4382 } 4383 4384 /* 4385 * Scan to the end of the list, but not past the entry for the 4386 * dynamic linker, which we want to keep at the very end. 4387 */ 4388 for (prev = r_debug.r_map; 4389 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4390 prev = prev->l_next) 4391 ; 4392 4393 /* Link in the new entry. */ 4394 l->l_prev = prev; 4395 l->l_next = prev->l_next; 4396 if (l->l_next != NULL) 4397 l->l_next->l_prev = l; 4398 prev->l_next = l; 4399 } 4400 4401 static void 4402 linkmap_delete(Obj_Entry *obj) 4403 { 4404 struct link_map *l; 4405 4406 l = &obj->linkmap; 4407 if (l->l_prev == NULL) { 4408 if ((r_debug.r_map = l->l_next) != NULL) 4409 l->l_next->l_prev = NULL; 4410 return; 4411 } 4412 4413 if ((l->l_prev->l_next = l->l_next) != NULL) 4414 l->l_next->l_prev = l->l_prev; 4415 } 4416 4417 /* 4418 * Function for the debugger to set a breakpoint on to gain control. 4419 * 4420 * The two parameters allow the debugger to easily find and determine 4421 * what the runtime loader is doing and to whom it is doing it. 4422 * 4423 * When the loadhook trap is hit (r_debug_state, set at program 4424 * initialization), the arguments can be found on the stack: 4425 * 4426 * +8 struct link_map *m 4427 * +4 struct r_debug *rd 4428 * +0 RetAddr 4429 */ 4430 void 4431 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4432 { 4433 /* 4434 * The following is a hack to force the compiler to emit calls to 4435 * this function, even when optimizing. If the function is empty, 4436 * the compiler is not obliged to emit any code for calls to it, 4437 * even when marked __noinline. However, gdb depends on those 4438 * calls being made. 4439 */ 4440 __compiler_membar(); 4441 } 4442 4443 /* 4444 * A function called after init routines have completed. This can be used to 4445 * break before a program's entry routine is called, and can be used when 4446 * main is not available in the symbol table. 4447 */ 4448 void 4449 _r_debug_postinit(struct link_map *m __unused) 4450 { 4451 4452 /* See r_debug_state(). */ 4453 __compiler_membar(); 4454 } 4455 4456 static void 4457 release_object(Obj_Entry *obj) 4458 { 4459 4460 if (obj->holdcount > 0) { 4461 obj->unholdfree = true; 4462 return; 4463 } 4464 munmap(obj->mapbase, obj->mapsize); 4465 linkmap_delete(obj); 4466 obj_free(obj); 4467 } 4468 4469 /* 4470 * Get address of the pointer variable in the main program. 4471 * Prefer non-weak symbol over the weak one. 4472 */ 4473 static const void ** 4474 get_program_var_addr(const char *name, RtldLockState *lockstate) 4475 { 4476 SymLook req; 4477 DoneList donelist; 4478 4479 symlook_init(&req, name); 4480 req.lockstate = lockstate; 4481 donelist_init(&donelist); 4482 if (symlook_global(&req, &donelist) != 0) 4483 return (NULL); 4484 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4485 return ((const void **)make_function_pointer(req.sym_out, 4486 req.defobj_out)); 4487 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4488 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4489 else 4490 return ((const void **)(req.defobj_out->relocbase + 4491 req.sym_out->st_value)); 4492 } 4493 4494 /* 4495 * Set a pointer variable in the main program to the given value. This 4496 * is used to set key variables such as "environ" before any of the 4497 * init functions are called. 4498 */ 4499 static void 4500 set_program_var(const char *name, const void *value) 4501 { 4502 const void **addr; 4503 4504 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4505 dbg("\"%s\": *%p <-- %p", name, addr, value); 4506 *addr = value; 4507 } 4508 } 4509 4510 /* 4511 * Search the global objects, including dependencies and main object, 4512 * for the given symbol. 4513 */ 4514 static int 4515 symlook_global(SymLook *req, DoneList *donelist) 4516 { 4517 SymLook req1; 4518 const Objlist_Entry *elm; 4519 int res; 4520 4521 symlook_init_from_req(&req1, req); 4522 4523 /* Search all objects loaded at program start up. */ 4524 if (req->defobj_out == NULL || (ld_dynamic_weak && 4525 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4526 res = symlook_list(&req1, &list_main, donelist); 4527 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4528 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4529 req->sym_out = req1.sym_out; 4530 req->defobj_out = req1.defobj_out; 4531 assert(req->defobj_out != NULL); 4532 } 4533 } 4534 4535 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4536 STAILQ_FOREACH(elm, &list_global, link) { 4537 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4538 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4539 break; 4540 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4541 if (res == 0 && (req->defobj_out == NULL || 4542 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4543 req->sym_out = req1.sym_out; 4544 req->defobj_out = req1.defobj_out; 4545 assert(req->defobj_out != NULL); 4546 } 4547 } 4548 4549 return (req->sym_out != NULL ? 0 : ESRCH); 4550 } 4551 4552 /* 4553 * Given a symbol name in a referencing object, find the corresponding 4554 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4555 * no definition was found. Returns a pointer to the Obj_Entry of the 4556 * defining object via the reference parameter DEFOBJ_OUT. 4557 */ 4558 static int 4559 symlook_default(SymLook *req, const Obj_Entry *refobj) 4560 { 4561 DoneList donelist; 4562 const Objlist_Entry *elm; 4563 SymLook req1; 4564 int res; 4565 4566 donelist_init(&donelist); 4567 symlook_init_from_req(&req1, req); 4568 4569 /* 4570 * Look first in the referencing object if linked symbolically, 4571 * and similarly handle protected symbols. 4572 */ 4573 res = symlook_obj(&req1, refobj); 4574 if (res == 0 && (refobj->symbolic || 4575 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4576 req->sym_out = req1.sym_out; 4577 req->defobj_out = req1.defobj_out; 4578 assert(req->defobj_out != NULL); 4579 } 4580 if (refobj->symbolic || req->defobj_out != NULL) 4581 donelist_check(&donelist, refobj); 4582 4583 symlook_global(req, &donelist); 4584 4585 /* Search all dlopened DAGs containing the referencing object. */ 4586 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4587 if (req->sym_out != NULL && (!ld_dynamic_weak || 4588 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4589 break; 4590 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4591 if (res == 0 && (req->sym_out == NULL || 4592 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4593 req->sym_out = req1.sym_out; 4594 req->defobj_out = req1.defobj_out; 4595 assert(req->defobj_out != NULL); 4596 } 4597 } 4598 4599 /* 4600 * Search the dynamic linker itself, and possibly resolve the 4601 * symbol from there. This is how the application links to 4602 * dynamic linker services such as dlopen. 4603 */ 4604 if (req->sym_out == NULL || 4605 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4606 res = symlook_obj(&req1, &obj_rtld); 4607 if (res == 0) { 4608 req->sym_out = req1.sym_out; 4609 req->defobj_out = req1.defobj_out; 4610 assert(req->defobj_out != NULL); 4611 } 4612 } 4613 4614 return (req->sym_out != NULL ? 0 : ESRCH); 4615 } 4616 4617 static int 4618 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4619 { 4620 const Elf_Sym *def; 4621 const Obj_Entry *defobj; 4622 const Objlist_Entry *elm; 4623 SymLook req1; 4624 int res; 4625 4626 def = NULL; 4627 defobj = NULL; 4628 STAILQ_FOREACH(elm, objlist, link) { 4629 if (donelist_check(dlp, elm->obj)) 4630 continue; 4631 symlook_init_from_req(&req1, req); 4632 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4633 if (def == NULL || (ld_dynamic_weak && 4634 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4635 def = req1.sym_out; 4636 defobj = req1.defobj_out; 4637 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4638 break; 4639 } 4640 } 4641 } 4642 if (def != NULL) { 4643 req->sym_out = def; 4644 req->defobj_out = defobj; 4645 return (0); 4646 } 4647 return (ESRCH); 4648 } 4649 4650 /* 4651 * Search the chain of DAGS cointed to by the given Needed_Entry 4652 * for a symbol of the given name. Each DAG is scanned completely 4653 * before advancing to the next one. Returns a pointer to the symbol, 4654 * or NULL if no definition was found. 4655 */ 4656 static int 4657 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4658 { 4659 const Elf_Sym *def; 4660 const Needed_Entry *n; 4661 const Obj_Entry *defobj; 4662 SymLook req1; 4663 int res; 4664 4665 def = NULL; 4666 defobj = NULL; 4667 symlook_init_from_req(&req1, req); 4668 for (n = needed; n != NULL; n = n->next) { 4669 if (n->obj == NULL || 4670 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4671 continue; 4672 if (def == NULL || (ld_dynamic_weak && 4673 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4674 def = req1.sym_out; 4675 defobj = req1.defobj_out; 4676 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4677 break; 4678 } 4679 } 4680 if (def != NULL) { 4681 req->sym_out = def; 4682 req->defobj_out = defobj; 4683 return (0); 4684 } 4685 return (ESRCH); 4686 } 4687 4688 /* 4689 * Search the symbol table of a single shared object for a symbol of 4690 * the given name and version, if requested. Returns a pointer to the 4691 * symbol, or NULL if no definition was found. If the object is 4692 * filter, return filtered symbol from filtee. 4693 * 4694 * The symbol's hash value is passed in for efficiency reasons; that 4695 * eliminates many recomputations of the hash value. 4696 */ 4697 int 4698 symlook_obj(SymLook *req, const Obj_Entry *obj) 4699 { 4700 DoneList donelist; 4701 SymLook req1; 4702 int flags, res, mres; 4703 4704 /* 4705 * If there is at least one valid hash at this point, we prefer to 4706 * use the faster GNU version if available. 4707 */ 4708 if (obj->valid_hash_gnu) 4709 mres = symlook_obj1_gnu(req, obj); 4710 else if (obj->valid_hash_sysv) 4711 mres = symlook_obj1_sysv(req, obj); 4712 else 4713 return (EINVAL); 4714 4715 if (mres == 0) { 4716 if (obj->needed_filtees != NULL) { 4717 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4718 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4719 donelist_init(&donelist); 4720 symlook_init_from_req(&req1, req); 4721 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4722 if (res == 0) { 4723 req->sym_out = req1.sym_out; 4724 req->defobj_out = req1.defobj_out; 4725 } 4726 return (res); 4727 } 4728 if (obj->needed_aux_filtees != NULL) { 4729 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4730 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4731 donelist_init(&donelist); 4732 symlook_init_from_req(&req1, req); 4733 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4734 if (res == 0) { 4735 req->sym_out = req1.sym_out; 4736 req->defobj_out = req1.defobj_out; 4737 return (res); 4738 } 4739 } 4740 } 4741 return (mres); 4742 } 4743 4744 /* Symbol match routine common to both hash functions */ 4745 static bool 4746 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4747 const unsigned long symnum) 4748 { 4749 Elf_Versym verndx; 4750 const Elf_Sym *symp; 4751 const char *strp; 4752 4753 symp = obj->symtab + symnum; 4754 strp = obj->strtab + symp->st_name; 4755 4756 switch (ELF_ST_TYPE(symp->st_info)) { 4757 case STT_FUNC: 4758 case STT_NOTYPE: 4759 case STT_OBJECT: 4760 case STT_COMMON: 4761 case STT_GNU_IFUNC: 4762 if (symp->st_value == 0) 4763 return (false); 4764 /* fallthrough */ 4765 case STT_TLS: 4766 if (symp->st_shndx != SHN_UNDEF) 4767 break; 4768 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4769 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4770 break; 4771 /* fallthrough */ 4772 default: 4773 return (false); 4774 } 4775 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4776 return (false); 4777 4778 if (req->ventry == NULL) { 4779 if (obj->versyms != NULL) { 4780 verndx = VER_NDX(obj->versyms[symnum]); 4781 if (verndx > obj->vernum) { 4782 _rtld_error( 4783 "%s: symbol %s references wrong version %d", 4784 obj->path, obj->strtab + symnum, verndx); 4785 return (false); 4786 } 4787 /* 4788 * If we are not called from dlsym (i.e. this 4789 * is a normal relocation from unversioned 4790 * binary), accept the symbol immediately if 4791 * it happens to have first version after this 4792 * shared object became versioned. Otherwise, 4793 * if symbol is versioned and not hidden, 4794 * remember it. If it is the only symbol with 4795 * this name exported by the shared object, it 4796 * will be returned as a match by the calling 4797 * function. If symbol is global (verndx < 2) 4798 * accept it unconditionally. 4799 */ 4800 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4801 verndx == VER_NDX_GIVEN) { 4802 result->sym_out = symp; 4803 return (true); 4804 } 4805 else if (verndx >= VER_NDX_GIVEN) { 4806 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4807 == 0) { 4808 if (result->vsymp == NULL) 4809 result->vsymp = symp; 4810 result->vcount++; 4811 } 4812 return (false); 4813 } 4814 } 4815 result->sym_out = symp; 4816 return (true); 4817 } 4818 if (obj->versyms == NULL) { 4819 if (object_match_name(obj, req->ventry->name)) { 4820 _rtld_error("%s: object %s should provide version %s " 4821 "for symbol %s", obj_rtld.path, obj->path, 4822 req->ventry->name, obj->strtab + symnum); 4823 return (false); 4824 } 4825 } else { 4826 verndx = VER_NDX(obj->versyms[symnum]); 4827 if (verndx > obj->vernum) { 4828 _rtld_error("%s: symbol %s references wrong version %d", 4829 obj->path, obj->strtab + symnum, verndx); 4830 return (false); 4831 } 4832 if (obj->vertab[verndx].hash != req->ventry->hash || 4833 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4834 /* 4835 * Version does not match. Look if this is a 4836 * global symbol and if it is not hidden. If 4837 * global symbol (verndx < 2) is available, 4838 * use it. Do not return symbol if we are 4839 * called by dlvsym, because dlvsym looks for 4840 * a specific version and default one is not 4841 * what dlvsym wants. 4842 */ 4843 if ((req->flags & SYMLOOK_DLSYM) || 4844 (verndx >= VER_NDX_GIVEN) || 4845 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4846 return (false); 4847 } 4848 } 4849 result->sym_out = symp; 4850 return (true); 4851 } 4852 4853 /* 4854 * Search for symbol using SysV hash function. 4855 * obj->buckets is known not to be NULL at this point; the test for this was 4856 * performed with the obj->valid_hash_sysv assignment. 4857 */ 4858 static int 4859 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4860 { 4861 unsigned long symnum; 4862 Sym_Match_Result matchres; 4863 4864 matchres.sym_out = NULL; 4865 matchres.vsymp = NULL; 4866 matchres.vcount = 0; 4867 4868 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4869 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4870 if (symnum >= obj->nchains) 4871 return (ESRCH); /* Bad object */ 4872 4873 if (matched_symbol(req, obj, &matchres, symnum)) { 4874 req->sym_out = matchres.sym_out; 4875 req->defobj_out = obj; 4876 return (0); 4877 } 4878 } 4879 if (matchres.vcount == 1) { 4880 req->sym_out = matchres.vsymp; 4881 req->defobj_out = obj; 4882 return (0); 4883 } 4884 return (ESRCH); 4885 } 4886 4887 /* Search for symbol using GNU hash function */ 4888 static int 4889 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4890 { 4891 Elf_Addr bloom_word; 4892 const Elf32_Word *hashval; 4893 Elf32_Word bucket; 4894 Sym_Match_Result matchres; 4895 unsigned int h1, h2; 4896 unsigned long symnum; 4897 4898 matchres.sym_out = NULL; 4899 matchres.vsymp = NULL; 4900 matchres.vcount = 0; 4901 4902 /* Pick right bitmask word from Bloom filter array */ 4903 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4904 obj->maskwords_bm_gnu]; 4905 4906 /* Calculate modulus word size of gnu hash and its derivative */ 4907 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4908 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4909 4910 /* Filter out the "definitely not in set" queries */ 4911 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4912 return (ESRCH); 4913 4914 /* Locate hash chain and corresponding value element*/ 4915 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4916 if (bucket == 0) 4917 return (ESRCH); 4918 hashval = &obj->chain_zero_gnu[bucket]; 4919 do { 4920 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4921 symnum = hashval - obj->chain_zero_gnu; 4922 if (matched_symbol(req, obj, &matchres, symnum)) { 4923 req->sym_out = matchres.sym_out; 4924 req->defobj_out = obj; 4925 return (0); 4926 } 4927 } 4928 } while ((*hashval++ & 1) == 0); 4929 if (matchres.vcount == 1) { 4930 req->sym_out = matchres.vsymp; 4931 req->defobj_out = obj; 4932 return (0); 4933 } 4934 return (ESRCH); 4935 } 4936 4937 static void 4938 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4939 { 4940 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4941 if (*main_local == NULL) 4942 *main_local = ""; 4943 4944 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4945 if (*fmt1 == NULL) 4946 *fmt1 = "\t%o => %p (%x)\n"; 4947 4948 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4949 if (*fmt2 == NULL) 4950 *fmt2 = "\t%o (%x)\n"; 4951 } 4952 4953 static void 4954 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4955 const char *main_local, const char *fmt1, const char *fmt2) 4956 { 4957 const char *fmt; 4958 int c; 4959 4960 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; /* XXX bogus */ 4961 while ((c = *fmt++) != '\0') { 4962 switch (c) { 4963 default: 4964 rtld_putchar(c); 4965 continue; 4966 case '\\': 4967 switch (c = *fmt) { 4968 case '\0': 4969 continue; 4970 case 'n': 4971 rtld_putchar('\n'); 4972 break; 4973 case 't': 4974 rtld_putchar('\t'); 4975 break; 4976 } 4977 break; 4978 case '%': 4979 switch (c = *fmt) { 4980 case '\0': 4981 continue; 4982 case '%': 4983 default: 4984 rtld_putchar(c); 4985 break; 4986 case 'A': 4987 rtld_putstr(main_local); 4988 break; 4989 case 'a': 4990 rtld_putstr(obj_main->path); 4991 break; 4992 case 'o': 4993 rtld_putstr(name); 4994 break; 4995 case 'p': 4996 rtld_putstr(path); 4997 break; 4998 case 'x': 4999 rtld_printf("%p", obj != NULL ? 5000 obj->mapbase : NULL); 5001 break; 5002 } 5003 break; 5004 } 5005 ++fmt; 5006 } 5007 } 5008 5009 static void 5010 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5011 { 5012 const char *fmt1, *fmt2, *main_local; 5013 const char *name, *path; 5014 bool first_spurious, list_containers; 5015 5016 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5017 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5018 5019 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5020 Needed_Entry *needed; 5021 5022 if (obj->marker) 5023 continue; 5024 if (list_containers && obj->needed != NULL) 5025 rtld_printf("%s:\n", obj->path); 5026 for (needed = obj->needed; needed; needed = needed->next) { 5027 if (needed->obj != NULL) { 5028 if (needed->obj->traced && !list_containers) 5029 continue; 5030 needed->obj->traced = true; 5031 path = needed->obj->path; 5032 } else 5033 path = "not found"; 5034 5035 name = obj->strtab + needed->name; 5036 trace_print_obj(obj, name, path, main_local, 5037 fmt1, fmt2); 5038 } 5039 } 5040 5041 if (show_preload) { 5042 first_spurious = true; 5043 TAILQ_FOREACH(obj, &obj_list, next) { 5044 if (obj->marker || obj == obj_main || obj->traced) 5045 continue; 5046 5047 if (first_spurious) { 5048 rtld_printf("[preloaded]\n"); 5049 first_spurious = false; 5050 } 5051 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5052 name = fname == NULL ? "<unknown>" : fname->name; 5053 trace_print_obj(obj, name, obj->path, main_local, 5054 fmt1, fmt2); 5055 } 5056 } 5057 } 5058 5059 /* 5060 * Unload a dlopened object and its dependencies from memory and from 5061 * our data structures. It is assumed that the DAG rooted in the 5062 * object has already been unreferenced, and that the object has a 5063 * reference count of 0. 5064 */ 5065 static void 5066 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5067 { 5068 Obj_Entry marker, *obj, *next; 5069 5070 assert(root->refcount == 0); 5071 5072 /* 5073 * Pass over the DAG removing unreferenced objects from 5074 * appropriate lists. 5075 */ 5076 unlink_object(root); 5077 5078 /* Unmap all objects that are no longer referenced. */ 5079 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5080 next = TAILQ_NEXT(obj, next); 5081 if (obj->marker || obj->refcount != 0) 5082 continue; 5083 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5084 obj->mapsize, 0, obj->path); 5085 dbg("unloading \"%s\"", obj->path); 5086 /* 5087 * Unlink the object now to prevent new references from 5088 * being acquired while the bind lock is dropped in 5089 * recursive dlclose() invocations. 5090 */ 5091 TAILQ_REMOVE(&obj_list, obj, next); 5092 obj_count--; 5093 5094 if (obj->filtees_loaded) { 5095 if (next != NULL) { 5096 init_marker(&marker); 5097 TAILQ_INSERT_BEFORE(next, &marker, next); 5098 unload_filtees(obj, lockstate); 5099 next = TAILQ_NEXT(&marker, next); 5100 TAILQ_REMOVE(&obj_list, &marker, next); 5101 } else 5102 unload_filtees(obj, lockstate); 5103 } 5104 release_object(obj); 5105 } 5106 } 5107 5108 static void 5109 unlink_object(Obj_Entry *root) 5110 { 5111 Objlist_Entry *elm; 5112 5113 if (root->refcount == 0) { 5114 /* Remove the object from the RTLD_GLOBAL list. */ 5115 objlist_remove(&list_global, root); 5116 5117 /* Remove the object from all objects' DAG lists. */ 5118 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5119 objlist_remove(&elm->obj->dldags, root); 5120 if (elm->obj != root) 5121 unlink_object(elm->obj); 5122 } 5123 } 5124 } 5125 5126 static void 5127 ref_dag(Obj_Entry *root) 5128 { 5129 Objlist_Entry *elm; 5130 5131 assert(root->dag_inited); 5132 STAILQ_FOREACH(elm, &root->dagmembers, link) 5133 elm->obj->refcount++; 5134 } 5135 5136 static void 5137 unref_dag(Obj_Entry *root) 5138 { 5139 Objlist_Entry *elm; 5140 5141 assert(root->dag_inited); 5142 STAILQ_FOREACH(elm, &root->dagmembers, link) 5143 elm->obj->refcount--; 5144 } 5145 5146 /* 5147 * Common code for MD __tls_get_addr(). 5148 */ 5149 static void * 5150 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5151 { 5152 Elf_Addr *newdtv, *dtv; 5153 RtldLockState lockstate; 5154 int to_copy; 5155 5156 dtv = *dtvp; 5157 /* Check dtv generation in case new modules have arrived */ 5158 if (dtv[0] != tls_dtv_generation) { 5159 if (!locked) 5160 wlock_acquire(rtld_bind_lock, &lockstate); 5161 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5162 to_copy = dtv[1]; 5163 if (to_copy > tls_max_index) 5164 to_copy = tls_max_index; 5165 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5166 newdtv[0] = tls_dtv_generation; 5167 newdtv[1] = tls_max_index; 5168 free(dtv); 5169 if (!locked) 5170 lock_release(rtld_bind_lock, &lockstate); 5171 dtv = *dtvp = newdtv; 5172 } 5173 5174 /* Dynamically allocate module TLS if necessary */ 5175 if (dtv[index + 1] == 0) { 5176 /* Signal safe, wlock will block out signals. */ 5177 if (!locked) 5178 wlock_acquire(rtld_bind_lock, &lockstate); 5179 if (!dtv[index + 1]) 5180 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5181 if (!locked) 5182 lock_release(rtld_bind_lock, &lockstate); 5183 } 5184 return ((void *)(dtv[index + 1] + offset)); 5185 } 5186 5187 void * 5188 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5189 { 5190 uintptr_t *dtv; 5191 5192 dtv = *dtvp; 5193 /* Check dtv generation in case new modules have arrived */ 5194 if (__predict_true(dtv[0] == tls_dtv_generation && 5195 dtv[index + 1] != 0)) 5196 return ((void *)(dtv[index + 1] + offset)); 5197 return (tls_get_addr_slow(dtvp, index, offset, false)); 5198 } 5199 5200 #ifdef TLS_VARIANT_I 5201 5202 /* 5203 * Return pointer to allocated TLS block 5204 */ 5205 static void * 5206 get_tls_block_ptr(void *tcb, size_t tcbsize) 5207 { 5208 size_t extra_size, post_size, pre_size, tls_block_size; 5209 size_t tls_init_align; 5210 5211 tls_init_align = MAX(obj_main->tlsalign, 1); 5212 5213 /* Compute fragments sizes. */ 5214 extra_size = tcbsize - TLS_TCB_SIZE; 5215 post_size = calculate_tls_post_size(tls_init_align); 5216 tls_block_size = tcbsize + post_size; 5217 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5218 5219 return ((char *)tcb - pre_size - extra_size); 5220 } 5221 5222 /* 5223 * Allocate Static TLS using the Variant I method. 5224 * 5225 * For details on the layout, see lib/libc/gen/tls.c. 5226 * 5227 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5228 * it is based on tls_last_offset, and TLS offsets here are really TCB 5229 * offsets, whereas libc's tls_static_space is just the executable's static 5230 * TLS segment. 5231 */ 5232 void * 5233 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5234 { 5235 Obj_Entry *obj; 5236 char *tls_block; 5237 Elf_Addr *dtv, **tcb; 5238 Elf_Addr addr; 5239 Elf_Addr i; 5240 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5241 size_t tls_init_align, tls_init_offset; 5242 5243 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5244 return (oldtcb); 5245 5246 assert(tcbsize >= TLS_TCB_SIZE); 5247 maxalign = MAX(tcbalign, tls_static_max_align); 5248 tls_init_align = MAX(obj_main->tlsalign, 1); 5249 5250 /* Compute fragmets sizes. */ 5251 extra_size = tcbsize - TLS_TCB_SIZE; 5252 post_size = calculate_tls_post_size(tls_init_align); 5253 tls_block_size = tcbsize + post_size; 5254 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5255 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5256 5257 /* Allocate whole TLS block */ 5258 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5259 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5260 5261 if (oldtcb != NULL) { 5262 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5263 tls_static_space); 5264 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5265 5266 /* Adjust the DTV. */ 5267 dtv = tcb[0]; 5268 for (i = 0; i < dtv[1]; i++) { 5269 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5270 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5271 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5272 } 5273 } 5274 } else { 5275 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5276 tcb[0] = dtv; 5277 dtv[0] = tls_dtv_generation; 5278 dtv[1] = tls_max_index; 5279 5280 for (obj = globallist_curr(objs); obj != NULL; 5281 obj = globallist_next(obj)) { 5282 if (obj->tlsoffset == 0) 5283 continue; 5284 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5285 addr = (Elf_Addr)tcb + obj->tlsoffset; 5286 if (tls_init_offset > 0) 5287 memset((void *)addr, 0, tls_init_offset); 5288 if (obj->tlsinitsize > 0) { 5289 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5290 obj->tlsinitsize); 5291 } 5292 if (obj->tlssize > obj->tlsinitsize) { 5293 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5294 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5295 } 5296 dtv[obj->tlsindex + 1] = addr; 5297 } 5298 } 5299 5300 return (tcb); 5301 } 5302 5303 void 5304 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5305 { 5306 Elf_Addr *dtv; 5307 Elf_Addr tlsstart, tlsend; 5308 size_t post_size; 5309 size_t dtvsize, i, tls_init_align; 5310 5311 assert(tcbsize >= TLS_TCB_SIZE); 5312 tls_init_align = MAX(obj_main->tlsalign, 1); 5313 5314 /* Compute fragments sizes. */ 5315 post_size = calculate_tls_post_size(tls_init_align); 5316 5317 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5318 tlsend = (Elf_Addr)tcb + tls_static_space; 5319 5320 dtv = *(Elf_Addr **)tcb; 5321 dtvsize = dtv[1]; 5322 for (i = 0; i < dtvsize; i++) { 5323 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5324 free((void*)dtv[i+2]); 5325 } 5326 } 5327 free(dtv); 5328 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5329 } 5330 5331 #endif /* TLS_VARIANT_I */ 5332 5333 #ifdef TLS_VARIANT_II 5334 5335 /* 5336 * Allocate Static TLS using the Variant II method. 5337 */ 5338 void * 5339 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5340 { 5341 Obj_Entry *obj; 5342 size_t size, ralign; 5343 char *tls; 5344 Elf_Addr *dtv, *olddtv; 5345 Elf_Addr segbase, oldsegbase, addr; 5346 size_t i; 5347 5348 ralign = tcbalign; 5349 if (tls_static_max_align > ralign) 5350 ralign = tls_static_max_align; 5351 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5352 5353 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5354 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5355 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5356 5357 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5358 ((Elf_Addr *)segbase)[0] = segbase; 5359 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5360 5361 dtv[0] = tls_dtv_generation; 5362 dtv[1] = tls_max_index; 5363 5364 if (oldtls) { 5365 /* 5366 * Copy the static TLS block over whole. 5367 */ 5368 oldsegbase = (Elf_Addr) oldtls; 5369 memcpy((void *)(segbase - tls_static_space), 5370 (const void *)(oldsegbase - tls_static_space), 5371 tls_static_space); 5372 5373 /* 5374 * If any dynamic TLS blocks have been created tls_get_addr(), 5375 * move them over. 5376 */ 5377 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5378 for (i = 0; i < olddtv[1]; i++) { 5379 if (olddtv[i + 2] < oldsegbase - size || 5380 olddtv[i + 2] > oldsegbase) { 5381 dtv[i + 2] = olddtv[i + 2]; 5382 olddtv[i + 2] = 0; 5383 } 5384 } 5385 5386 /* 5387 * We assume that this block was the one we created with 5388 * allocate_initial_tls(). 5389 */ 5390 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5391 } else { 5392 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5393 if (obj->marker || obj->tlsoffset == 0) 5394 continue; 5395 addr = segbase - obj->tlsoffset; 5396 memset((void *)(addr + obj->tlsinitsize), 5397 0, obj->tlssize - obj->tlsinitsize); 5398 if (obj->tlsinit) { 5399 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5400 obj->static_tls_copied = true; 5401 } 5402 dtv[obj->tlsindex + 1] = addr; 5403 } 5404 } 5405 5406 return ((void *)segbase); 5407 } 5408 5409 void 5410 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5411 { 5412 Elf_Addr* dtv; 5413 size_t size, ralign; 5414 int dtvsize, i; 5415 Elf_Addr tlsstart, tlsend; 5416 5417 /* 5418 * Figure out the size of the initial TLS block so that we can 5419 * find stuff which ___tls_get_addr() allocated dynamically. 5420 */ 5421 ralign = tcbalign; 5422 if (tls_static_max_align > ralign) 5423 ralign = tls_static_max_align; 5424 size = roundup(tls_static_space, ralign); 5425 5426 dtv = ((Elf_Addr **)tls)[1]; 5427 dtvsize = dtv[1]; 5428 tlsend = (Elf_Addr)tls; 5429 tlsstart = tlsend - size; 5430 for (i = 0; i < dtvsize; i++) { 5431 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5432 dtv[i + 2] > tlsend)) { 5433 free_aligned((void *)dtv[i + 2]); 5434 } 5435 } 5436 5437 free_aligned((void *)tlsstart); 5438 free((void *)dtv); 5439 } 5440 5441 #endif /* TLS_VARIANT_II */ 5442 5443 /* 5444 * Allocate TLS block for module with given index. 5445 */ 5446 void * 5447 allocate_module_tls(int index) 5448 { 5449 Obj_Entry *obj; 5450 char *p; 5451 5452 TAILQ_FOREACH(obj, &obj_list, next) { 5453 if (obj->marker) 5454 continue; 5455 if (obj->tlsindex == index) 5456 break; 5457 } 5458 if (obj == NULL) { 5459 _rtld_error("Can't find module with TLS index %d", index); 5460 rtld_die(); 5461 } 5462 5463 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5464 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5465 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5466 return (p); 5467 } 5468 5469 bool 5470 allocate_tls_offset(Obj_Entry *obj) 5471 { 5472 size_t off; 5473 5474 if (obj->tls_done) 5475 return (true); 5476 5477 if (obj->tlssize == 0) { 5478 obj->tls_done = true; 5479 return (true); 5480 } 5481 5482 if (tls_last_offset == 0) 5483 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5484 obj->tlspoffset); 5485 else 5486 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5487 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5488 5489 obj->tlsoffset = off; 5490 #ifdef TLS_VARIANT_I 5491 off += obj->tlssize; 5492 #endif 5493 5494 /* 5495 * If we have already fixed the size of the static TLS block, we 5496 * must stay within that size. When allocating the static TLS, we 5497 * leave a small amount of space spare to be used for dynamically 5498 * loading modules which use static TLS. 5499 */ 5500 if (tls_static_space != 0) { 5501 if (off > tls_static_space) 5502 return (false); 5503 } else if (obj->tlsalign > tls_static_max_align) { 5504 tls_static_max_align = obj->tlsalign; 5505 } 5506 5507 tls_last_offset = off; 5508 tls_last_size = obj->tlssize; 5509 obj->tls_done = true; 5510 5511 return (true); 5512 } 5513 5514 void 5515 free_tls_offset(Obj_Entry *obj) 5516 { 5517 5518 /* 5519 * If we were the last thing to allocate out of the static TLS 5520 * block, we give our space back to the 'allocator'. This is a 5521 * simplistic workaround to allow libGL.so.1 to be loaded and 5522 * unloaded multiple times. 5523 */ 5524 size_t off = obj->tlsoffset; 5525 #ifdef TLS_VARIANT_I 5526 off += obj->tlssize; 5527 #endif 5528 if (off == tls_last_offset) { 5529 tls_last_offset -= obj->tlssize; 5530 tls_last_size = 0; 5531 } 5532 } 5533 5534 void * 5535 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5536 { 5537 void *ret; 5538 RtldLockState lockstate; 5539 5540 wlock_acquire(rtld_bind_lock, &lockstate); 5541 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5542 tcbsize, tcbalign); 5543 lock_release(rtld_bind_lock, &lockstate); 5544 return (ret); 5545 } 5546 5547 void 5548 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5549 { 5550 RtldLockState lockstate; 5551 5552 wlock_acquire(rtld_bind_lock, &lockstate); 5553 free_tls(tcb, tcbsize, tcbalign); 5554 lock_release(rtld_bind_lock, &lockstate); 5555 } 5556 5557 static void 5558 object_add_name(Obj_Entry *obj, const char *name) 5559 { 5560 Name_Entry *entry; 5561 size_t len; 5562 5563 len = strlen(name); 5564 entry = malloc(sizeof(Name_Entry) + len); 5565 5566 if (entry != NULL) { 5567 strcpy(entry->name, name); 5568 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5569 } 5570 } 5571 5572 static int 5573 object_match_name(const Obj_Entry *obj, const char *name) 5574 { 5575 Name_Entry *entry; 5576 5577 STAILQ_FOREACH(entry, &obj->names, link) { 5578 if (strcmp(name, entry->name) == 0) 5579 return (1); 5580 } 5581 return (0); 5582 } 5583 5584 static Obj_Entry * 5585 locate_dependency(const Obj_Entry *obj, const char *name) 5586 { 5587 const Objlist_Entry *entry; 5588 const Needed_Entry *needed; 5589 5590 STAILQ_FOREACH(entry, &list_main, link) { 5591 if (object_match_name(entry->obj, name)) 5592 return (entry->obj); 5593 } 5594 5595 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5596 if (strcmp(obj->strtab + needed->name, name) == 0 || 5597 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5598 /* 5599 * If there is DT_NEEDED for the name we are looking for, 5600 * we are all set. Note that object might not be found if 5601 * dependency was not loaded yet, so the function can 5602 * return NULL here. This is expected and handled 5603 * properly by the caller. 5604 */ 5605 return (needed->obj); 5606 } 5607 } 5608 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5609 obj->path, name); 5610 rtld_die(); 5611 } 5612 5613 static int 5614 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5615 const Elf_Vernaux *vna) 5616 { 5617 const Elf_Verdef *vd; 5618 const char *vername; 5619 5620 vername = refobj->strtab + vna->vna_name; 5621 vd = depobj->verdef; 5622 if (vd == NULL) { 5623 _rtld_error("%s: version %s required by %s not defined", 5624 depobj->path, vername, refobj->path); 5625 return (-1); 5626 } 5627 for (;;) { 5628 if (vd->vd_version != VER_DEF_CURRENT) { 5629 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5630 depobj->path, vd->vd_version); 5631 return (-1); 5632 } 5633 if (vna->vna_hash == vd->vd_hash) { 5634 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5635 ((const char *)vd + vd->vd_aux); 5636 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5637 return (0); 5638 } 5639 if (vd->vd_next == 0) 5640 break; 5641 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5642 } 5643 if (vna->vna_flags & VER_FLG_WEAK) 5644 return (0); 5645 _rtld_error("%s: version %s required by %s not found", 5646 depobj->path, vername, refobj->path); 5647 return (-1); 5648 } 5649 5650 static int 5651 rtld_verify_object_versions(Obj_Entry *obj) 5652 { 5653 const Elf_Verneed *vn; 5654 const Elf_Verdef *vd; 5655 const Elf_Verdaux *vda; 5656 const Elf_Vernaux *vna; 5657 const Obj_Entry *depobj; 5658 int maxvernum, vernum; 5659 5660 if (obj->ver_checked) 5661 return (0); 5662 obj->ver_checked = true; 5663 5664 maxvernum = 0; 5665 /* 5666 * Walk over defined and required version records and figure out 5667 * max index used by any of them. Do very basic sanity checking 5668 * while there. 5669 */ 5670 vn = obj->verneed; 5671 while (vn != NULL) { 5672 if (vn->vn_version != VER_NEED_CURRENT) { 5673 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5674 obj->path, vn->vn_version); 5675 return (-1); 5676 } 5677 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5678 for (;;) { 5679 vernum = VER_NEED_IDX(vna->vna_other); 5680 if (vernum > maxvernum) 5681 maxvernum = vernum; 5682 if (vna->vna_next == 0) 5683 break; 5684 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5685 } 5686 if (vn->vn_next == 0) 5687 break; 5688 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5689 } 5690 5691 vd = obj->verdef; 5692 while (vd != NULL) { 5693 if (vd->vd_version != VER_DEF_CURRENT) { 5694 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5695 obj->path, vd->vd_version); 5696 return (-1); 5697 } 5698 vernum = VER_DEF_IDX(vd->vd_ndx); 5699 if (vernum > maxvernum) 5700 maxvernum = vernum; 5701 if (vd->vd_next == 0) 5702 break; 5703 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5704 } 5705 5706 if (maxvernum == 0) 5707 return (0); 5708 5709 /* 5710 * Store version information in array indexable by version index. 5711 * Verify that object version requirements are satisfied along the 5712 * way. 5713 */ 5714 obj->vernum = maxvernum + 1; 5715 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5716 5717 vd = obj->verdef; 5718 while (vd != NULL) { 5719 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5720 vernum = VER_DEF_IDX(vd->vd_ndx); 5721 assert(vernum <= maxvernum); 5722 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5723 obj->vertab[vernum].hash = vd->vd_hash; 5724 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5725 obj->vertab[vernum].file = NULL; 5726 obj->vertab[vernum].flags = 0; 5727 } 5728 if (vd->vd_next == 0) 5729 break; 5730 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5731 } 5732 5733 vn = obj->verneed; 5734 while (vn != NULL) { 5735 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5736 if (depobj == NULL) 5737 return (-1); 5738 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5739 for (;;) { 5740 if (check_object_provided_version(obj, depobj, vna)) 5741 return (-1); 5742 vernum = VER_NEED_IDX(vna->vna_other); 5743 assert(vernum <= maxvernum); 5744 obj->vertab[vernum].hash = vna->vna_hash; 5745 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5746 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5747 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5748 VER_INFO_HIDDEN : 0; 5749 if (vna->vna_next == 0) 5750 break; 5751 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5752 } 5753 if (vn->vn_next == 0) 5754 break; 5755 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5756 } 5757 return (0); 5758 } 5759 5760 static int 5761 rtld_verify_versions(const Objlist *objlist) 5762 { 5763 Objlist_Entry *entry; 5764 int rc; 5765 5766 rc = 0; 5767 STAILQ_FOREACH(entry, objlist, link) { 5768 /* 5769 * Skip dummy objects or objects that have their version requirements 5770 * already checked. 5771 */ 5772 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5773 continue; 5774 if (rtld_verify_object_versions(entry->obj) == -1) { 5775 rc = -1; 5776 if (ld_tracing == NULL) 5777 break; 5778 } 5779 } 5780 if (rc == 0 || ld_tracing != NULL) 5781 rc = rtld_verify_object_versions(&obj_rtld); 5782 return (rc); 5783 } 5784 5785 const Ver_Entry * 5786 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5787 { 5788 Elf_Versym vernum; 5789 5790 if (obj->vertab) { 5791 vernum = VER_NDX(obj->versyms[symnum]); 5792 if (vernum >= obj->vernum) { 5793 _rtld_error("%s: symbol %s has wrong verneed value %d", 5794 obj->path, obj->strtab + symnum, vernum); 5795 } else if (obj->vertab[vernum].hash != 0) { 5796 return (&obj->vertab[vernum]); 5797 } 5798 } 5799 return (NULL); 5800 } 5801 5802 int 5803 _rtld_get_stack_prot(void) 5804 { 5805 5806 return (stack_prot); 5807 } 5808 5809 int 5810 _rtld_is_dlopened(void *arg) 5811 { 5812 Obj_Entry *obj; 5813 RtldLockState lockstate; 5814 int res; 5815 5816 rlock_acquire(rtld_bind_lock, &lockstate); 5817 obj = dlcheck(arg); 5818 if (obj == NULL) 5819 obj = obj_from_addr(arg); 5820 if (obj == NULL) { 5821 _rtld_error("No shared object contains address"); 5822 lock_release(rtld_bind_lock, &lockstate); 5823 return (-1); 5824 } 5825 res = obj->dlopened ? 1 : 0; 5826 lock_release(rtld_bind_lock, &lockstate); 5827 return (res); 5828 } 5829 5830 static int 5831 obj_remap_relro(Obj_Entry *obj, int prot) 5832 { 5833 5834 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5835 prot) == -1) { 5836 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5837 obj->path, prot, rtld_strerror(errno)); 5838 return (-1); 5839 } 5840 return (0); 5841 } 5842 5843 static int 5844 obj_disable_relro(Obj_Entry *obj) 5845 { 5846 5847 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5848 } 5849 5850 static int 5851 obj_enforce_relro(Obj_Entry *obj) 5852 { 5853 5854 return (obj_remap_relro(obj, PROT_READ)); 5855 } 5856 5857 static void 5858 map_stacks_exec(RtldLockState *lockstate) 5859 { 5860 void (*thr_map_stacks_exec)(void); 5861 5862 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5863 return; 5864 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5865 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5866 if (thr_map_stacks_exec != NULL) { 5867 stack_prot |= PROT_EXEC; 5868 thr_map_stacks_exec(); 5869 } 5870 } 5871 5872 static void 5873 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5874 { 5875 Objlist_Entry *elm; 5876 Obj_Entry *obj; 5877 void (*distrib)(size_t, void *, size_t, size_t); 5878 5879 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5880 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5881 if (distrib == NULL) 5882 return; 5883 STAILQ_FOREACH(elm, list, link) { 5884 obj = elm->obj; 5885 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5886 continue; 5887 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5888 obj->tlssize); 5889 obj->static_tls_copied = true; 5890 } 5891 } 5892 5893 void 5894 symlook_init(SymLook *dst, const char *name) 5895 { 5896 5897 bzero(dst, sizeof(*dst)); 5898 dst->name = name; 5899 dst->hash = elf_hash(name); 5900 dst->hash_gnu = gnu_hash(name); 5901 } 5902 5903 static void 5904 symlook_init_from_req(SymLook *dst, const SymLook *src) 5905 { 5906 5907 dst->name = src->name; 5908 dst->hash = src->hash; 5909 dst->hash_gnu = src->hash_gnu; 5910 dst->ventry = src->ventry; 5911 dst->flags = src->flags; 5912 dst->defobj_out = NULL; 5913 dst->sym_out = NULL; 5914 dst->lockstate = src->lockstate; 5915 } 5916 5917 static int 5918 open_binary_fd(const char *argv0, bool search_in_path, 5919 const char **binpath_res) 5920 { 5921 char *binpath, *pathenv, *pe, *res1; 5922 const char *res; 5923 int fd; 5924 5925 binpath = NULL; 5926 res = NULL; 5927 if (search_in_path && strchr(argv0, '/') == NULL) { 5928 binpath = xmalloc(PATH_MAX); 5929 pathenv = getenv("PATH"); 5930 if (pathenv == NULL) { 5931 _rtld_error("-p and no PATH environment variable"); 5932 rtld_die(); 5933 } 5934 pathenv = strdup(pathenv); 5935 if (pathenv == NULL) { 5936 _rtld_error("Cannot allocate memory"); 5937 rtld_die(); 5938 } 5939 fd = -1; 5940 errno = ENOENT; 5941 while ((pe = strsep(&pathenv, ":")) != NULL) { 5942 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5943 continue; 5944 if (binpath[0] != '\0' && 5945 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5946 continue; 5947 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5948 continue; 5949 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5950 if (fd != -1 || errno != ENOENT) { 5951 res = binpath; 5952 break; 5953 } 5954 } 5955 free(pathenv); 5956 } else { 5957 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5958 res = argv0; 5959 } 5960 5961 if (fd == -1) { 5962 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5963 rtld_die(); 5964 } 5965 if (res != NULL && res[0] != '/') { 5966 res1 = xmalloc(PATH_MAX); 5967 if (realpath(res, res1) != NULL) { 5968 if (res != argv0) 5969 free(__DECONST(char *, res)); 5970 res = res1; 5971 } else { 5972 free(res1); 5973 } 5974 } 5975 *binpath_res = res; 5976 return (fd); 5977 } 5978 5979 /* 5980 * Parse a set of command-line arguments. 5981 */ 5982 static int 5983 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5984 const char **argv0, bool *dir_ignore) 5985 { 5986 const char *arg; 5987 char machine[64]; 5988 size_t sz; 5989 int arglen, fd, i, j, mib[2]; 5990 char opt; 5991 bool seen_b, seen_f; 5992 5993 dbg("Parsing command-line arguments"); 5994 *use_pathp = false; 5995 *fdp = -1; 5996 *dir_ignore = false; 5997 seen_b = seen_f = false; 5998 5999 for (i = 1; i < argc; i++ ) { 6000 arg = argv[i]; 6001 dbg("argv[%d]: '%s'", i, arg); 6002 6003 /* 6004 * rtld arguments end with an explicit "--" or with the first 6005 * non-prefixed argument. 6006 */ 6007 if (strcmp(arg, "--") == 0) { 6008 i++; 6009 break; 6010 } 6011 if (arg[0] != '-') 6012 break; 6013 6014 /* 6015 * All other arguments are single-character options that can 6016 * be combined, so we need to search through `arg` for them. 6017 */ 6018 arglen = strlen(arg); 6019 for (j = 1; j < arglen; j++) { 6020 opt = arg[j]; 6021 if (opt == 'h') { 6022 print_usage(argv[0]); 6023 _exit(0); 6024 } else if (opt == 'b') { 6025 if (seen_f) { 6026 _rtld_error("Both -b and -f specified"); 6027 rtld_die(); 6028 } 6029 i++; 6030 *argv0 = argv[i]; 6031 seen_b = true; 6032 break; 6033 } else if (opt == 'd') { 6034 *dir_ignore = true; 6035 break; 6036 } else if (opt == 'f') { 6037 if (seen_b) { 6038 _rtld_error("Both -b and -f specified"); 6039 rtld_die(); 6040 } 6041 6042 /* 6043 * -f XX can be used to specify a 6044 * descriptor for the binary named at 6045 * the command line (i.e., the later 6046 * argument will specify the process 6047 * name but the descriptor is what 6048 * will actually be executed). 6049 * 6050 * -f must be the last option in, e.g., -abcf. 6051 */ 6052 if (j != arglen - 1) { 6053 _rtld_error("Invalid options: %s", arg); 6054 rtld_die(); 6055 } 6056 i++; 6057 fd = parse_integer(argv[i]); 6058 if (fd == -1) { 6059 _rtld_error( 6060 "Invalid file descriptor: '%s'", 6061 argv[i]); 6062 rtld_die(); 6063 } 6064 *fdp = fd; 6065 seen_f = true; 6066 break; 6067 } else if (opt == 'p') { 6068 *use_pathp = true; 6069 } else if (opt == 'u') { 6070 trust = false; 6071 } else if (opt == 'v') { 6072 machine[0] = '\0'; 6073 mib[0] = CTL_HW; 6074 mib[1] = HW_MACHINE; 6075 sz = sizeof(machine); 6076 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6077 ld_elf_hints_path = ld_get_env_var( 6078 LD_ELF_HINTS_PATH); 6079 set_ld_elf_hints_path(); 6080 rtld_printf( 6081 "FreeBSD ld-elf.so.1 %s\n" 6082 "FreeBSD_version %d\n" 6083 "Default lib path %s\n" 6084 "Hints lib path %s\n" 6085 "Env prefix %s\n" 6086 "Default hint file %s\n" 6087 "Hint file %s\n" 6088 "libmap file %s\n", 6089 machine, 6090 __FreeBSD_version, ld_standard_library_path, 6091 gethints(false), 6092 ld_env_prefix, ld_elf_hints_default, 6093 ld_elf_hints_path, 6094 ld_path_libmap_conf); 6095 _exit(0); 6096 } else { 6097 _rtld_error("Invalid argument: '%s'", arg); 6098 print_usage(argv[0]); 6099 rtld_die(); 6100 } 6101 } 6102 } 6103 6104 if (!seen_b) 6105 *argv0 = argv[i]; 6106 return (i); 6107 } 6108 6109 /* 6110 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6111 */ 6112 static int 6113 parse_integer(const char *str) 6114 { 6115 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6116 const char *orig; 6117 int n; 6118 char c; 6119 6120 orig = str; 6121 n = 0; 6122 for (c = *str; c != '\0'; c = *++str) { 6123 if (c < '0' || c > '9') 6124 return (-1); 6125 6126 n *= RADIX; 6127 n += c - '0'; 6128 } 6129 6130 /* Make sure we actually parsed something. */ 6131 if (str == orig) 6132 return (-1); 6133 return (n); 6134 } 6135 6136 static void 6137 print_usage(const char *argv0) 6138 { 6139 6140 rtld_printf( 6141 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6142 "\n" 6143 "Options:\n" 6144 " -h Display this help message\n" 6145 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6146 " -d Ignore lack of exec permissions for the binary\n" 6147 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6148 " -p Search in PATH for named binary\n" 6149 " -u Ignore LD_ environment variables\n" 6150 " -v Display identification information\n" 6151 " -- End of RTLD options\n" 6152 " <binary> Name of process to execute\n" 6153 " <args> Arguments to the executed process\n", argv0); 6154 } 6155 6156 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6157 static const struct auxfmt { 6158 const char *name; 6159 const char *fmt; 6160 } auxfmts[] = { 6161 AUXFMT(AT_NULL, NULL), 6162 AUXFMT(AT_IGNORE, NULL), 6163 AUXFMT(AT_EXECFD, "%ld"), 6164 AUXFMT(AT_PHDR, "%p"), 6165 AUXFMT(AT_PHENT, "%lu"), 6166 AUXFMT(AT_PHNUM, "%lu"), 6167 AUXFMT(AT_PAGESZ, "%lu"), 6168 AUXFMT(AT_BASE, "%#lx"), 6169 AUXFMT(AT_FLAGS, "%#lx"), 6170 AUXFMT(AT_ENTRY, "%p"), 6171 AUXFMT(AT_NOTELF, NULL), 6172 AUXFMT(AT_UID, "%ld"), 6173 AUXFMT(AT_EUID, "%ld"), 6174 AUXFMT(AT_GID, "%ld"), 6175 AUXFMT(AT_EGID, "%ld"), 6176 AUXFMT(AT_EXECPATH, "%s"), 6177 AUXFMT(AT_CANARY, "%p"), 6178 AUXFMT(AT_CANARYLEN, "%lu"), 6179 AUXFMT(AT_OSRELDATE, "%lu"), 6180 AUXFMT(AT_NCPUS, "%lu"), 6181 AUXFMT(AT_PAGESIZES, "%p"), 6182 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6183 AUXFMT(AT_TIMEKEEP, "%p"), 6184 AUXFMT(AT_STACKPROT, "%#lx"), 6185 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6186 AUXFMT(AT_HWCAP, "%#lx"), 6187 AUXFMT(AT_HWCAP2, "%#lx"), 6188 AUXFMT(AT_BSDFLAGS, "%#lx"), 6189 AUXFMT(AT_ARGC, "%lu"), 6190 AUXFMT(AT_ARGV, "%p"), 6191 AUXFMT(AT_ENVC, "%p"), 6192 AUXFMT(AT_ENVV, "%p"), 6193 AUXFMT(AT_PS_STRINGS, "%p"), 6194 AUXFMT(AT_FXRNG, "%p"), 6195 AUXFMT(AT_KPRELOAD, "%p"), 6196 }; 6197 6198 static bool 6199 is_ptr_fmt(const char *fmt) 6200 { 6201 char last; 6202 6203 last = fmt[strlen(fmt) - 1]; 6204 return (last == 'p' || last == 's'); 6205 } 6206 6207 static void 6208 dump_auxv(Elf_Auxinfo **aux_info) 6209 { 6210 Elf_Auxinfo *auxp; 6211 const struct auxfmt *fmt; 6212 int i; 6213 6214 for (i = 0; i < AT_COUNT; i++) { 6215 auxp = aux_info[i]; 6216 if (auxp == NULL) 6217 continue; 6218 fmt = &auxfmts[i]; 6219 if (fmt->fmt == NULL) 6220 continue; 6221 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6222 if (is_ptr_fmt(fmt->fmt)) { 6223 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6224 auxp->a_un.a_ptr); 6225 } else { 6226 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6227 auxp->a_un.a_val); 6228 } 6229 rtld_fdprintf(STDOUT_FILENO, "\n"); 6230 } 6231 } 6232 6233 /* 6234 * Overrides for libc_pic-provided functions. 6235 */ 6236 6237 int 6238 __getosreldate(void) 6239 { 6240 size_t len; 6241 int oid[2]; 6242 int error, osrel; 6243 6244 if (osreldate != 0) 6245 return (osreldate); 6246 6247 oid[0] = CTL_KERN; 6248 oid[1] = KERN_OSRELDATE; 6249 osrel = 0; 6250 len = sizeof(osrel); 6251 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6252 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6253 osreldate = osrel; 6254 return (osreldate); 6255 } 6256 const char * 6257 rtld_strerror(int errnum) 6258 { 6259 6260 if (errnum < 0 || errnum >= sys_nerr) 6261 return ("Unknown error"); 6262 return (sys_errlist[errnum]); 6263 } 6264 6265 char * 6266 getenv(const char *name) 6267 { 6268 return (__DECONST(char *, rtld_get_env_val(environ, name, 6269 strlen(name)))); 6270 } 6271 6272 /* malloc */ 6273 void * 6274 malloc(size_t nbytes) 6275 { 6276 6277 return (__crt_malloc(nbytes)); 6278 } 6279 6280 void * 6281 calloc(size_t num, size_t size) 6282 { 6283 6284 return (__crt_calloc(num, size)); 6285 } 6286 6287 void 6288 free(void *cp) 6289 { 6290 6291 __crt_free(cp); 6292 } 6293 6294 void * 6295 realloc(void *cp, size_t nbytes) 6296 { 6297 6298 return (__crt_realloc(cp, nbytes)); 6299 } 6300 6301 extern int _rtld_version__FreeBSD_version __exported; 6302 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6303 6304 extern char _rtld_version_laddr_offset __exported; 6305 char _rtld_version_laddr_offset; 6306 6307 extern char _rtld_version_dlpi_tls_data __exported; 6308 char _rtld_version_dlpi_tls_data; 6309