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 int npagesizes; 268 static int osreldate; 269 size_t *pagesizes; 270 size_t page_size; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 enum { 348 LD_BIND_NOW = 0, 349 LD_PRELOAD, 350 LD_LIBMAP, 351 LD_LIBRARY_PATH, 352 LD_LIBRARY_PATH_FDS, 353 LD_LIBMAP_DISABLE, 354 LD_BIND_NOT, 355 LD_DEBUG, 356 LD_ELF_HINTS_PATH, 357 LD_LOADFLTR, 358 LD_LIBRARY_PATH_RPATH, 359 LD_PRELOAD_FDS, 360 LD_DYNAMIC_WEAK, 361 LD_TRACE_LOADED_OBJECTS, 362 LD_UTRACE, 363 LD_DUMP_REL_PRE, 364 LD_DUMP_REL_POST, 365 LD_TRACE_LOADED_OBJECTS_PROGNAME, 366 LD_TRACE_LOADED_OBJECTS_FMT1, 367 LD_TRACE_LOADED_OBJECTS_FMT2, 368 LD_TRACE_LOADED_OBJECTS_ALL, 369 LD_SHOW_AUXV, 370 }; 371 372 struct ld_env_var_desc { 373 const char * const n; 374 const char *val; 375 const bool unsecure; 376 }; 377 #define LD_ENV_DESC(var, unsec) \ 378 [LD_##var] = { .n = #var, .unsecure = unsec } 379 380 static struct ld_env_var_desc ld_env_vars[] = { 381 LD_ENV_DESC(BIND_NOW, false), 382 LD_ENV_DESC(PRELOAD, true), 383 LD_ENV_DESC(LIBMAP, true), 384 LD_ENV_DESC(LIBRARY_PATH, true), 385 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 386 LD_ENV_DESC(LIBMAP_DISABLE, true), 387 LD_ENV_DESC(BIND_NOT, true), 388 LD_ENV_DESC(DEBUG, true), 389 LD_ENV_DESC(ELF_HINTS_PATH, true), 390 LD_ENV_DESC(LOADFLTR, true), 391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 392 LD_ENV_DESC(PRELOAD_FDS, true), 393 LD_ENV_DESC(DYNAMIC_WEAK, true), 394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 395 LD_ENV_DESC(UTRACE, false), 396 LD_ENV_DESC(DUMP_REL_PRE, false), 397 LD_ENV_DESC(DUMP_REL_POST, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 402 LD_ENV_DESC(SHOW_AUXV, false), 403 }; 404 405 static const char * 406 ld_get_env_var(int idx) 407 { 408 return (ld_env_vars[idx].val); 409 } 410 411 static const char * 412 rtld_get_env_val(char **env, const char *name, size_t name_len) 413 { 414 char **m, *n, *v; 415 416 for (m = env; *m != NULL; m++) { 417 n = *m; 418 v = strchr(n, '='); 419 if (v == NULL) { 420 /* corrupt environment? */ 421 continue; 422 } 423 if (v - n == (ptrdiff_t)name_len && 424 strncmp(name, n, name_len) == 0) 425 return (v + 1); 426 } 427 return (NULL); 428 } 429 430 static void 431 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 432 { 433 struct ld_env_var_desc *lvd; 434 size_t prefix_len, nlen; 435 char **m, *n, *v; 436 int i; 437 438 prefix_len = strlen(env_prefix); 439 for (m = env; *m != NULL; m++) { 440 n = *m; 441 if (strncmp(env_prefix, n, prefix_len) != 0) { 442 /* Not a rtld environment variable. */ 443 continue; 444 } 445 n += prefix_len; 446 v = strchr(n, '='); 447 if (v == NULL) { 448 /* corrupt environment? */ 449 continue; 450 } 451 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 452 lvd = &ld_env_vars[i]; 453 if (lvd->val != NULL) { 454 /* Saw higher-priority variable name already. */ 455 continue; 456 } 457 nlen = strlen(lvd->n); 458 if (v - n == (ptrdiff_t)nlen && 459 strncmp(lvd->n, n, nlen) == 0) { 460 lvd->val = v + 1; 461 break; 462 } 463 } 464 } 465 } 466 467 static void 468 rtld_init_env_vars(char **env) 469 { 470 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 471 } 472 473 static void 474 set_ld_elf_hints_path(void) 475 { 476 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 477 ld_elf_hints_path = ld_elf_hints_default; 478 } 479 480 uintptr_t 481 rtld_round_page(uintptr_t x) 482 { 483 return (roundup2(x, page_size)); 484 } 485 486 uintptr_t 487 rtld_trunc_page(uintptr_t x) 488 { 489 return (rounddown2(x, page_size)); 490 } 491 492 /* 493 * Main entry point for dynamic linking. The first argument is the 494 * stack pointer. The stack is expected to be laid out as described 495 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 496 * Specifically, the stack pointer points to a word containing 497 * ARGC. Following that in the stack is a null-terminated sequence 498 * of pointers to argument strings. Then comes a null-terminated 499 * sequence of pointers to environment strings. Finally, there is a 500 * sequence of "auxiliary vector" entries. 501 * 502 * The second argument points to a place to store the dynamic linker's 503 * exit procedure pointer and the third to a place to store the main 504 * program's object. 505 * 506 * The return value is the main program's entry point. 507 */ 508 func_ptr_type 509 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 510 { 511 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 512 Objlist_Entry *entry; 513 Obj_Entry *last_interposer, *obj, *preload_tail; 514 const Elf_Phdr *phdr; 515 Objlist initlist; 516 RtldLockState lockstate; 517 struct stat st; 518 Elf_Addr *argcp; 519 char **argv, **env, **envp, *kexecpath; 520 const char *argv0, *binpath, *library_path_rpath; 521 struct ld_env_var_desc *lvd; 522 caddr_t imgentry; 523 char buf[MAXPATHLEN]; 524 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 525 size_t sz; 526 #ifdef __powerpc__ 527 int old_auxv_format = 1; 528 #endif 529 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 530 531 /* 532 * On entry, the dynamic linker itself has not been relocated yet. 533 * Be very careful not to reference any global data until after 534 * init_rtld has returned. It is OK to reference file-scope statics 535 * and string constants, and to call static and global functions. 536 */ 537 538 /* Find the auxiliary vector on the stack. */ 539 argcp = sp; 540 argc = *sp++; 541 argv = (char **) sp; 542 sp += argc + 1; /* Skip over arguments and NULL terminator */ 543 env = (char **) sp; 544 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 545 ; 546 aux = (Elf_Auxinfo *) sp; 547 548 /* Digest the auxiliary vector. */ 549 for (i = 0; i < AT_COUNT; i++) 550 aux_info[i] = NULL; 551 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 552 if (auxp->a_type < AT_COUNT) 553 aux_info[auxp->a_type] = auxp; 554 #ifdef __powerpc__ 555 if (auxp->a_type == 23) /* AT_STACKPROT */ 556 old_auxv_format = 0; 557 #endif 558 } 559 560 #ifdef __powerpc__ 561 if (old_auxv_format) { 562 /* Remap from old-style auxv numbers. */ 563 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 564 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 565 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 566 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 567 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 568 aux_info[13] = NULL; /* AT_GID */ 569 570 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 571 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 572 aux_info[16] = aux_info[14]; /* AT_CANARY */ 573 aux_info[14] = NULL; /* AT_EGID */ 574 } 575 #endif 576 577 /* Initialize and relocate ourselves. */ 578 assert(aux_info[AT_BASE] != NULL); 579 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 580 581 dlerror_dflt_init(); 582 583 __progname = obj_rtld.path; 584 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 585 environ = env; 586 main_argc = argc; 587 main_argv = argv; 588 589 if (aux_info[AT_BSDFLAGS] != NULL && 590 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 591 ld_fast_sigblock = true; 592 593 trust = !issetugid(); 594 direct_exec = false; 595 596 md_abi_variant_hook(aux_info); 597 rtld_init_env_vars(env); 598 599 fd = -1; 600 if (aux_info[AT_EXECFD] != NULL) { 601 fd = aux_info[AT_EXECFD]->a_un.a_val; 602 } else { 603 assert(aux_info[AT_PHDR] != NULL); 604 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 605 if (phdr == obj_rtld.phdr) { 606 if (!trust) { 607 _rtld_error("Tainted process refusing to run binary %s", 608 argv0); 609 rtld_die(); 610 } 611 direct_exec = true; 612 613 dbg("opening main program in direct exec mode"); 614 if (argc >= 2) { 615 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 616 &argv0, &dir_ignore); 617 explicit_fd = (fd != -1); 618 binpath = NULL; 619 if (!explicit_fd) 620 fd = open_binary_fd(argv0, search_in_path, &binpath); 621 if (fstat(fd, &st) == -1) { 622 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 623 explicit_fd ? "user-provided descriptor" : argv0, 624 rtld_strerror(errno)); 625 rtld_die(); 626 } 627 628 /* 629 * Rough emulation of the permission checks done by 630 * execve(2), only Unix DACs are checked, ACLs are 631 * ignored. Preserve the semantic of disabling owner 632 * to execute if owner x bit is cleared, even if 633 * others x bit is enabled. 634 * mmap(2) does not allow to mmap with PROT_EXEC if 635 * binary' file comes from noexec mount. We cannot 636 * set a text reference on the binary. 637 */ 638 dir_enable = false; 639 if (st.st_uid == geteuid()) { 640 if ((st.st_mode & S_IXUSR) != 0) 641 dir_enable = true; 642 } else if (st.st_gid == getegid()) { 643 if ((st.st_mode & S_IXGRP) != 0) 644 dir_enable = true; 645 } else if ((st.st_mode & S_IXOTH) != 0) { 646 dir_enable = true; 647 } 648 if (!dir_enable && !dir_ignore) { 649 _rtld_error("No execute permission for binary %s", 650 argv0); 651 rtld_die(); 652 } 653 654 /* 655 * For direct exec mode, argv[0] is the interpreter 656 * name, we must remove it and shift arguments left 657 * before invoking binary main. Since stack layout 658 * places environment pointers and aux vectors right 659 * after the terminating NULL, we must shift 660 * environment and aux as well. 661 */ 662 main_argc = argc - rtld_argc; 663 for (i = 0; i <= main_argc; i++) 664 argv[i] = argv[i + rtld_argc]; 665 *argcp -= rtld_argc; 666 environ = env = envp = argv + main_argc + 1; 667 dbg("move env from %p to %p", envp + rtld_argc, envp); 668 do { 669 *envp = *(envp + rtld_argc); 670 } while (*envp++ != NULL); 671 aux = auxp = (Elf_Auxinfo *)envp; 672 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 673 dbg("move aux from %p to %p", auxpf, aux); 674 /* XXXKIB insert place for AT_EXECPATH if not present */ 675 for (;; auxp++, auxpf++) { 676 *auxp = *auxpf; 677 if (auxp->a_type == AT_NULL) 678 break; 679 } 680 /* Since the auxiliary vector has moved, redigest it. */ 681 for (i = 0; i < AT_COUNT; i++) 682 aux_info[i] = NULL; 683 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 684 if (auxp->a_type < AT_COUNT) 685 aux_info[auxp->a_type] = auxp; 686 } 687 688 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 689 if (binpath == NULL) { 690 aux_info[AT_EXECPATH] = NULL; 691 } else { 692 if (aux_info[AT_EXECPATH] == NULL) { 693 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 694 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 695 } 696 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 697 binpath); 698 } 699 } else { 700 _rtld_error("No binary"); 701 rtld_die(); 702 } 703 } 704 } 705 706 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 707 708 /* 709 * If the process is tainted, then we un-set the dangerous environment 710 * variables. The process will be marked as tainted until setuid(2) 711 * is called. If any child process calls setuid(2) we do not want any 712 * future processes to honor the potentially un-safe variables. 713 */ 714 if (!trust) { 715 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 716 lvd = &ld_env_vars[i]; 717 if (lvd->unsecure) 718 lvd->val = NULL; 719 } 720 } 721 722 ld_debug = ld_get_env_var(LD_DEBUG); 723 if (ld_bind_now == NULL) 724 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 725 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 726 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 727 libmap_override = ld_get_env_var(LD_LIBMAP); 728 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 729 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 730 ld_preload = ld_get_env_var(LD_PRELOAD); 731 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 732 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 733 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 734 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 735 if (library_path_rpath != NULL) { 736 if (library_path_rpath[0] == 'y' || 737 library_path_rpath[0] == 'Y' || 738 library_path_rpath[0] == '1') 739 ld_library_path_rpath = true; 740 else 741 ld_library_path_rpath = false; 742 } 743 dangerous_ld_env = libmap_disable || libmap_override != NULL || 744 ld_library_path != NULL || ld_preload != NULL || 745 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 746 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 747 ld_utrace = ld_get_env_var(LD_UTRACE); 748 749 set_ld_elf_hints_path(); 750 if (ld_debug != NULL && *ld_debug != '\0') 751 debug = 1; 752 dbg("%s is initialized, base address = %p", __progname, 753 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 754 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 755 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 756 757 dbg("initializing thread locks"); 758 lockdflt_init(); 759 760 /* 761 * Load the main program, or process its program header if it is 762 * already loaded. 763 */ 764 if (fd != -1) { /* Load the main program. */ 765 dbg("loading main program"); 766 obj_main = map_object(fd, argv0, NULL); 767 close(fd); 768 if (obj_main == NULL) 769 rtld_die(); 770 max_stack_flags = obj_main->stack_flags; 771 } else { /* Main program already loaded. */ 772 dbg("processing main program's program header"); 773 assert(aux_info[AT_PHDR] != NULL); 774 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 775 assert(aux_info[AT_PHNUM] != NULL); 776 phnum = aux_info[AT_PHNUM]->a_un.a_val; 777 assert(aux_info[AT_PHENT] != NULL); 778 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 779 assert(aux_info[AT_ENTRY] != NULL); 780 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 781 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 782 rtld_die(); 783 } 784 785 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 786 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 787 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 788 if (kexecpath[0] == '/') 789 obj_main->path = kexecpath; 790 else if (getcwd(buf, sizeof(buf)) == NULL || 791 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 792 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 793 obj_main->path = xstrdup(argv0); 794 else 795 obj_main->path = xstrdup(buf); 796 } else { 797 dbg("No AT_EXECPATH or direct exec"); 798 obj_main->path = xstrdup(argv0); 799 } 800 dbg("obj_main path %s", obj_main->path); 801 obj_main->mainprog = true; 802 803 if (aux_info[AT_STACKPROT] != NULL && 804 aux_info[AT_STACKPROT]->a_un.a_val != 0) 805 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 806 807 #ifndef COMPAT_32BIT 808 /* 809 * Get the actual dynamic linker pathname from the executable if 810 * possible. (It should always be possible.) That ensures that 811 * gdb will find the right dynamic linker even if a non-standard 812 * one is being used. 813 */ 814 if (obj_main->interp != NULL && 815 strcmp(obj_main->interp, obj_rtld.path) != 0) { 816 free(obj_rtld.path); 817 obj_rtld.path = xstrdup(obj_main->interp); 818 __progname = obj_rtld.path; 819 } 820 #endif 821 822 if (!digest_dynamic(obj_main, 0)) 823 rtld_die(); 824 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 825 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 826 obj_main->dynsymcount); 827 828 linkmap_add(obj_main); 829 linkmap_add(&obj_rtld); 830 831 /* Link the main program into the list of objects. */ 832 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 833 obj_count++; 834 obj_loads++; 835 836 /* Initialize a fake symbol for resolving undefined weak references. */ 837 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 838 sym_zero.st_shndx = SHN_UNDEF; 839 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 840 841 if (!libmap_disable) 842 libmap_disable = (bool)lm_init(libmap_override); 843 844 if (aux_info[AT_KPRELOAD] != NULL && 845 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 846 dbg("loading kernel vdso"); 847 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 848 rtld_die(); 849 } 850 851 dbg("loading LD_PRELOAD_FDS libraries"); 852 if (load_preload_objects(ld_preload_fds, true) == -1) 853 rtld_die(); 854 855 dbg("loading LD_PRELOAD libraries"); 856 if (load_preload_objects(ld_preload, false) == -1) 857 rtld_die(); 858 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 859 860 dbg("loading needed objects"); 861 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 862 0) == -1) 863 rtld_die(); 864 865 /* Make a list of all objects loaded at startup. */ 866 last_interposer = obj_main; 867 TAILQ_FOREACH(obj, &obj_list, next) { 868 if (obj->marker) 869 continue; 870 if (obj->z_interpose && obj != obj_main) { 871 objlist_put_after(&list_main, last_interposer, obj); 872 last_interposer = obj; 873 } else { 874 objlist_push_tail(&list_main, obj); 875 } 876 obj->refcount++; 877 } 878 879 dbg("checking for required versions"); 880 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 881 rtld_die(); 882 883 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 884 dump_auxv(aux_info); 885 886 if (ld_tracing) { /* We're done */ 887 trace_loaded_objects(obj_main, true); 888 exit(0); 889 } 890 891 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 892 dump_relocations(obj_main); 893 exit (0); 894 } 895 896 /* 897 * Processing tls relocations requires having the tls offsets 898 * initialized. Prepare offsets before starting initial 899 * relocation processing. 900 */ 901 dbg("initializing initial thread local storage offsets"); 902 STAILQ_FOREACH(entry, &list_main, link) { 903 /* 904 * Allocate all the initial objects out of the static TLS 905 * block even if they didn't ask for it. 906 */ 907 allocate_tls_offset(entry->obj); 908 } 909 910 if (relocate_objects(obj_main, 911 ld_bind_now != NULL && *ld_bind_now != '\0', 912 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 913 rtld_die(); 914 915 dbg("doing copy relocations"); 916 if (do_copy_relocations(obj_main) == -1) 917 rtld_die(); 918 919 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 920 dump_relocations(obj_main); 921 exit (0); 922 } 923 924 ifunc_init(aux); 925 926 /* 927 * Setup TLS for main thread. This must be done after the 928 * relocations are processed, since tls initialization section 929 * might be the subject for relocations. 930 */ 931 dbg("initializing initial thread local storage"); 932 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 933 934 dbg("initializing key program variables"); 935 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 936 set_program_var("environ", env); 937 set_program_var("__elf_aux_vector", aux); 938 939 /* Make a list of init functions to call. */ 940 objlist_init(&initlist); 941 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 942 preload_tail, &initlist); 943 944 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 945 946 map_stacks_exec(NULL); 947 948 if (!obj_main->crt_no_init) { 949 /* 950 * Make sure we don't call the main program's init and fini 951 * functions for binaries linked with old crt1 which calls 952 * _init itself. 953 */ 954 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 955 obj_main->preinit_array = obj_main->init_array = 956 obj_main->fini_array = (Elf_Addr)NULL; 957 } 958 959 if (direct_exec) { 960 /* Set osrel for direct-execed binary */ 961 mib[0] = CTL_KERN; 962 mib[1] = KERN_PROC; 963 mib[2] = KERN_PROC_OSREL; 964 mib[3] = getpid(); 965 osrel = obj_main->osrel; 966 sz = sizeof(old_osrel); 967 dbg("setting osrel to %d", osrel); 968 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 969 } 970 971 wlock_acquire(rtld_bind_lock, &lockstate); 972 973 dbg("resolving ifuncs"); 974 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 975 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 976 rtld_die(); 977 978 rtld_exit_ptr = rtld_exit; 979 if (obj_main->crt_no_init) 980 preinit_main(); 981 objlist_call_init(&initlist, &lockstate); 982 _r_debug_postinit(&obj_main->linkmap); 983 objlist_clear(&initlist); 984 dbg("loading filtees"); 985 TAILQ_FOREACH(obj, &obj_list, next) { 986 if (obj->marker) 987 continue; 988 if (ld_loadfltr || obj->z_loadfltr) 989 load_filtees(obj, 0, &lockstate); 990 } 991 992 dbg("enforcing main obj relro"); 993 if (obj_enforce_relro(obj_main) == -1) 994 rtld_die(); 995 996 lock_release(rtld_bind_lock, &lockstate); 997 998 dbg("transferring control to program entry point = %p", obj_main->entry); 999 1000 /* Return the exit procedure and the program entry point. */ 1001 *exit_proc = rtld_exit_ptr; 1002 *objp = obj_main; 1003 return ((func_ptr_type)obj_main->entry); 1004 } 1005 1006 void * 1007 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 1008 { 1009 void *ptr; 1010 Elf_Addr target; 1011 1012 ptr = (void *)make_function_pointer(def, obj); 1013 target = call_ifunc_resolver(ptr); 1014 return ((void *)target); 1015 } 1016 1017 Elf_Addr 1018 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1019 { 1020 const Elf_Rel *rel; 1021 const Elf_Sym *def; 1022 const Obj_Entry *defobj; 1023 Elf_Addr *where; 1024 Elf_Addr target; 1025 RtldLockState lockstate; 1026 1027 rlock_acquire(rtld_bind_lock, &lockstate); 1028 if (sigsetjmp(lockstate.env, 0) != 0) 1029 lock_upgrade(rtld_bind_lock, &lockstate); 1030 if (obj->pltrel) 1031 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1032 else 1033 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1034 1035 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1036 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1037 NULL, &lockstate); 1038 if (def == NULL) 1039 rtld_die(); 1040 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1041 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1042 else 1043 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1044 1045 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1046 defobj->strtab + def->st_name, 1047 obj->path == NULL ? NULL : basename(obj->path), 1048 (void *)target, 1049 defobj->path == NULL ? NULL : basename(defobj->path)); 1050 1051 /* 1052 * Write the new contents for the jmpslot. Note that depending on 1053 * architecture, the value which we need to return back to the 1054 * lazy binding trampoline may or may not be the target 1055 * address. The value returned from reloc_jmpslot() is the value 1056 * that the trampoline needs. 1057 */ 1058 target = reloc_jmpslot(where, target, defobj, obj, rel); 1059 lock_release(rtld_bind_lock, &lockstate); 1060 return (target); 1061 } 1062 1063 /* 1064 * Error reporting function. Use it like printf. If formats the message 1065 * into a buffer, and sets things up so that the next call to dlerror() 1066 * will return the message. 1067 */ 1068 void 1069 _rtld_error(const char *fmt, ...) 1070 { 1071 va_list ap; 1072 1073 va_start(ap, fmt); 1074 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1075 fmt, ap); 1076 va_end(ap); 1077 *lockinfo.dlerror_seen() = 0; 1078 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1079 } 1080 1081 /* 1082 * Return a dynamically-allocated copy of the current error message, if any. 1083 */ 1084 static struct dlerror_save * 1085 errmsg_save(void) 1086 { 1087 struct dlerror_save *res; 1088 1089 res = xmalloc(sizeof(*res)); 1090 res->seen = *lockinfo.dlerror_seen(); 1091 if (res->seen == 0) 1092 res->msg = xstrdup(lockinfo.dlerror_loc()); 1093 return (res); 1094 } 1095 1096 /* 1097 * Restore the current error message from a copy which was previously saved 1098 * by errmsg_save(). The copy is freed. 1099 */ 1100 static void 1101 errmsg_restore(struct dlerror_save *saved_msg) 1102 { 1103 if (saved_msg == NULL || saved_msg->seen == 1) { 1104 *lockinfo.dlerror_seen() = 1; 1105 } else { 1106 *lockinfo.dlerror_seen() = 0; 1107 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1108 lockinfo.dlerror_loc_sz); 1109 free(saved_msg->msg); 1110 } 1111 free(saved_msg); 1112 } 1113 1114 static const char * 1115 basename(const char *name) 1116 { 1117 const char *p; 1118 1119 p = strrchr(name, '/'); 1120 return (p != NULL ? p + 1 : name); 1121 } 1122 1123 static struct utsname uts; 1124 1125 static char * 1126 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1127 const char *subst, bool may_free) 1128 { 1129 char *p, *p1, *res, *resp; 1130 int subst_len, kw_len, subst_count, old_len, new_len; 1131 1132 kw_len = strlen(kw); 1133 1134 /* 1135 * First, count the number of the keyword occurrences, to 1136 * preallocate the final string. 1137 */ 1138 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1139 p1 = strstr(p, kw); 1140 if (p1 == NULL) 1141 break; 1142 } 1143 1144 /* 1145 * If the keyword is not found, just return. 1146 * 1147 * Return non-substituted string if resolution failed. We 1148 * cannot do anything more reasonable, the failure mode of the 1149 * caller is unresolved library anyway. 1150 */ 1151 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1152 return (may_free ? real : xstrdup(real)); 1153 if (obj != NULL) 1154 subst = obj->origin_path; 1155 1156 /* 1157 * There is indeed something to substitute. Calculate the 1158 * length of the resulting string, and allocate it. 1159 */ 1160 subst_len = strlen(subst); 1161 old_len = strlen(real); 1162 new_len = old_len + (subst_len - kw_len) * subst_count; 1163 res = xmalloc(new_len + 1); 1164 1165 /* 1166 * Now, execute the substitution loop. 1167 */ 1168 for (p = real, resp = res, *resp = '\0';;) { 1169 p1 = strstr(p, kw); 1170 if (p1 != NULL) { 1171 /* Copy the prefix before keyword. */ 1172 memcpy(resp, p, p1 - p); 1173 resp += p1 - p; 1174 /* Keyword replacement. */ 1175 memcpy(resp, subst, subst_len); 1176 resp += subst_len; 1177 *resp = '\0'; 1178 p = p1 + kw_len; 1179 } else 1180 break; 1181 } 1182 1183 /* Copy to the end of string and finish. */ 1184 strcat(resp, p); 1185 if (may_free) 1186 free(real); 1187 return (res); 1188 } 1189 1190 static const struct { 1191 const char *kw; 1192 bool pass_obj; 1193 const char *subst; 1194 } tokens[] = { 1195 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1196 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1197 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1198 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1199 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1200 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1201 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1202 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1203 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, 1204 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, 1205 }; 1206 1207 static char * 1208 origin_subst(Obj_Entry *obj, const char *real) 1209 { 1210 char *res; 1211 int i; 1212 1213 if (obj == NULL || !trust) 1214 return (xstrdup(real)); 1215 if (uts.sysname[0] == '\0') { 1216 if (uname(&uts) != 0) { 1217 _rtld_error("utsname failed: %d", errno); 1218 return (NULL); 1219 } 1220 } 1221 1222 /* __DECONST is safe here since without may_free real is unchanged */ 1223 res = __DECONST(char *, real); 1224 for (i = 0; i < (int)nitems(tokens); i++) { 1225 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1226 res, tokens[i].kw, tokens[i].subst, i != 0); 1227 } 1228 return (res); 1229 } 1230 1231 void 1232 rtld_die(void) 1233 { 1234 const char *msg = dlerror(); 1235 1236 if (msg == NULL) 1237 msg = "Fatal error"; 1238 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1239 rtld_fdputstr(STDERR_FILENO, msg); 1240 rtld_fdputchar(STDERR_FILENO, '\n'); 1241 _exit(1); 1242 } 1243 1244 /* 1245 * Process a shared object's DYNAMIC section, and save the important 1246 * information in its Obj_Entry structure. 1247 */ 1248 static void 1249 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1250 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1251 { 1252 const Elf_Dyn *dynp; 1253 Needed_Entry **needed_tail = &obj->needed; 1254 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1255 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1256 const Elf_Hashelt *hashtab; 1257 const Elf32_Word *hashval; 1258 Elf32_Word bkt, nmaskwords; 1259 int bloom_size32; 1260 int plttype = DT_REL; 1261 1262 *dyn_rpath = NULL; 1263 *dyn_soname = NULL; 1264 *dyn_runpath = NULL; 1265 1266 obj->bind_now = false; 1267 dynp = obj->dynamic; 1268 if (dynp == NULL) 1269 return; 1270 for (; dynp->d_tag != DT_NULL; dynp++) { 1271 switch (dynp->d_tag) { 1272 1273 case DT_REL: 1274 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1275 break; 1276 1277 case DT_RELSZ: 1278 obj->relsize = dynp->d_un.d_val; 1279 break; 1280 1281 case DT_RELENT: 1282 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1283 break; 1284 1285 case DT_JMPREL: 1286 obj->pltrel = (const Elf_Rel *) 1287 (obj->relocbase + dynp->d_un.d_ptr); 1288 break; 1289 1290 case DT_PLTRELSZ: 1291 obj->pltrelsize = dynp->d_un.d_val; 1292 break; 1293 1294 case DT_RELA: 1295 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1296 break; 1297 1298 case DT_RELASZ: 1299 obj->relasize = dynp->d_un.d_val; 1300 break; 1301 1302 case DT_RELAENT: 1303 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1304 break; 1305 1306 case DT_RELR: 1307 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1308 break; 1309 1310 case DT_RELRSZ: 1311 obj->relrsize = dynp->d_un.d_val; 1312 break; 1313 1314 case DT_RELRENT: 1315 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1316 break; 1317 1318 case DT_PLTREL: 1319 plttype = dynp->d_un.d_val; 1320 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1321 break; 1322 1323 case DT_SYMTAB: 1324 obj->symtab = (const Elf_Sym *) 1325 (obj->relocbase + dynp->d_un.d_ptr); 1326 break; 1327 1328 case DT_SYMENT: 1329 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1330 break; 1331 1332 case DT_STRTAB: 1333 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1334 break; 1335 1336 case DT_STRSZ: 1337 obj->strsize = dynp->d_un.d_val; 1338 break; 1339 1340 case DT_VERNEED: 1341 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1342 dynp->d_un.d_val); 1343 break; 1344 1345 case DT_VERNEEDNUM: 1346 obj->verneednum = dynp->d_un.d_val; 1347 break; 1348 1349 case DT_VERDEF: 1350 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1351 dynp->d_un.d_val); 1352 break; 1353 1354 case DT_VERDEFNUM: 1355 obj->verdefnum = dynp->d_un.d_val; 1356 break; 1357 1358 case DT_VERSYM: 1359 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1360 dynp->d_un.d_val); 1361 break; 1362 1363 case DT_HASH: 1364 { 1365 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1366 dynp->d_un.d_ptr); 1367 obj->nbuckets = hashtab[0]; 1368 obj->nchains = hashtab[1]; 1369 obj->buckets = hashtab + 2; 1370 obj->chains = obj->buckets + obj->nbuckets; 1371 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1372 obj->buckets != NULL; 1373 } 1374 break; 1375 1376 case DT_GNU_HASH: 1377 { 1378 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1379 dynp->d_un.d_ptr); 1380 obj->nbuckets_gnu = hashtab[0]; 1381 obj->symndx_gnu = hashtab[1]; 1382 nmaskwords = hashtab[2]; 1383 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1384 obj->maskwords_bm_gnu = nmaskwords - 1; 1385 obj->shift2_gnu = hashtab[3]; 1386 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1387 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1388 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1389 obj->symndx_gnu; 1390 /* Number of bitmask words is required to be power of 2 */ 1391 obj->valid_hash_gnu = powerof2(nmaskwords) && 1392 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1393 } 1394 break; 1395 1396 case DT_NEEDED: 1397 if (!obj->rtld) { 1398 Needed_Entry *nep = NEW(Needed_Entry); 1399 nep->name = dynp->d_un.d_val; 1400 nep->obj = NULL; 1401 nep->next = NULL; 1402 1403 *needed_tail = nep; 1404 needed_tail = &nep->next; 1405 } 1406 break; 1407 1408 case DT_FILTER: 1409 if (!obj->rtld) { 1410 Needed_Entry *nep = NEW(Needed_Entry); 1411 nep->name = dynp->d_un.d_val; 1412 nep->obj = NULL; 1413 nep->next = NULL; 1414 1415 *needed_filtees_tail = nep; 1416 needed_filtees_tail = &nep->next; 1417 1418 if (obj->linkmap.l_refname == NULL) 1419 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1420 } 1421 break; 1422 1423 case DT_AUXILIARY: 1424 if (!obj->rtld) { 1425 Needed_Entry *nep = NEW(Needed_Entry); 1426 nep->name = dynp->d_un.d_val; 1427 nep->obj = NULL; 1428 nep->next = NULL; 1429 1430 *needed_aux_filtees_tail = nep; 1431 needed_aux_filtees_tail = &nep->next; 1432 } 1433 break; 1434 1435 case DT_PLTGOT: 1436 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1437 break; 1438 1439 case DT_TEXTREL: 1440 obj->textrel = true; 1441 break; 1442 1443 case DT_SYMBOLIC: 1444 obj->symbolic = true; 1445 break; 1446 1447 case DT_RPATH: 1448 /* 1449 * We have to wait until later to process this, because we 1450 * might not have gotten the address of the string table yet. 1451 */ 1452 *dyn_rpath = dynp; 1453 break; 1454 1455 case DT_SONAME: 1456 *dyn_soname = dynp; 1457 break; 1458 1459 case DT_RUNPATH: 1460 *dyn_runpath = dynp; 1461 break; 1462 1463 case DT_INIT: 1464 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1465 break; 1466 1467 case DT_PREINIT_ARRAY: 1468 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1469 break; 1470 1471 case DT_PREINIT_ARRAYSZ: 1472 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1473 break; 1474 1475 case DT_INIT_ARRAY: 1476 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1477 break; 1478 1479 case DT_INIT_ARRAYSZ: 1480 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1481 break; 1482 1483 case DT_FINI: 1484 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1485 break; 1486 1487 case DT_FINI_ARRAY: 1488 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1489 break; 1490 1491 case DT_FINI_ARRAYSZ: 1492 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1493 break; 1494 1495 case DT_DEBUG: 1496 if (!early) 1497 dbg("Filling in DT_DEBUG entry"); 1498 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1499 break; 1500 1501 case DT_FLAGS: 1502 if (dynp->d_un.d_val & DF_ORIGIN) 1503 obj->z_origin = true; 1504 if (dynp->d_un.d_val & DF_SYMBOLIC) 1505 obj->symbolic = true; 1506 if (dynp->d_un.d_val & DF_TEXTREL) 1507 obj->textrel = true; 1508 if (dynp->d_un.d_val & DF_BIND_NOW) 1509 obj->bind_now = true; 1510 if (dynp->d_un.d_val & DF_STATIC_TLS) 1511 obj->static_tls = true; 1512 break; 1513 1514 #ifdef __powerpc__ 1515 #ifdef __powerpc64__ 1516 case DT_PPC64_GLINK: 1517 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1518 break; 1519 #else 1520 case DT_PPC_GOT: 1521 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1522 break; 1523 #endif 1524 #endif 1525 1526 case DT_FLAGS_1: 1527 if (dynp->d_un.d_val & DF_1_NOOPEN) 1528 obj->z_noopen = true; 1529 if (dynp->d_un.d_val & DF_1_ORIGIN) 1530 obj->z_origin = true; 1531 if (dynp->d_un.d_val & DF_1_GLOBAL) 1532 obj->z_global = true; 1533 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1534 obj->bind_now = true; 1535 if (dynp->d_un.d_val & DF_1_NODELETE) 1536 obj->z_nodelete = true; 1537 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1538 obj->z_loadfltr = true; 1539 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1540 obj->z_interpose = true; 1541 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1542 obj->z_nodeflib = true; 1543 if (dynp->d_un.d_val & DF_1_PIE) 1544 obj->z_pie = true; 1545 break; 1546 1547 default: 1548 if (!early) { 1549 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1550 (long)dynp->d_tag); 1551 } 1552 break; 1553 } 1554 } 1555 1556 obj->traced = false; 1557 1558 if (plttype == DT_RELA) { 1559 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1560 obj->pltrel = NULL; 1561 obj->pltrelasize = obj->pltrelsize; 1562 obj->pltrelsize = 0; 1563 } 1564 1565 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1566 if (obj->valid_hash_sysv) 1567 obj->dynsymcount = obj->nchains; 1568 else if (obj->valid_hash_gnu) { 1569 obj->dynsymcount = 0; 1570 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1571 if (obj->buckets_gnu[bkt] == 0) 1572 continue; 1573 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1574 do 1575 obj->dynsymcount++; 1576 while ((*hashval++ & 1u) == 0); 1577 } 1578 obj->dynsymcount += obj->symndx_gnu; 1579 } 1580 1581 if (obj->linkmap.l_refname != NULL) 1582 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1583 linkmap.l_refname; 1584 } 1585 1586 static bool 1587 obj_resolve_origin(Obj_Entry *obj) 1588 { 1589 1590 if (obj->origin_path != NULL) 1591 return (true); 1592 obj->origin_path = xmalloc(PATH_MAX); 1593 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1594 } 1595 1596 static bool 1597 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1598 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1599 { 1600 1601 if (obj->z_origin && !obj_resolve_origin(obj)) 1602 return (false); 1603 1604 if (dyn_runpath != NULL) { 1605 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1606 obj->runpath = origin_subst(obj, obj->runpath); 1607 } else if (dyn_rpath != NULL) { 1608 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1609 obj->rpath = origin_subst(obj, obj->rpath); 1610 } 1611 if (dyn_soname != NULL) 1612 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1613 return (true); 1614 } 1615 1616 static bool 1617 digest_dynamic(Obj_Entry *obj, int early) 1618 { 1619 const Elf_Dyn *dyn_rpath; 1620 const Elf_Dyn *dyn_soname; 1621 const Elf_Dyn *dyn_runpath; 1622 1623 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1624 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1625 } 1626 1627 /* 1628 * Process a shared object's program header. This is used only for the 1629 * main program, when the kernel has already loaded the main program 1630 * into memory before calling the dynamic linker. It creates and 1631 * returns an Obj_Entry structure. 1632 */ 1633 static Obj_Entry * 1634 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1635 { 1636 Obj_Entry *obj; 1637 const Elf_Phdr *phlimit = phdr + phnum; 1638 const Elf_Phdr *ph; 1639 Elf_Addr note_start, note_end; 1640 int nsegs = 0; 1641 1642 obj = obj_new(); 1643 for (ph = phdr; ph < phlimit; ph++) { 1644 if (ph->p_type != PT_PHDR) 1645 continue; 1646 1647 obj->phdr = phdr; 1648 obj->phsize = ph->p_memsz; 1649 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1650 break; 1651 } 1652 1653 obj->stack_flags = PF_X | PF_R | PF_W; 1654 1655 for (ph = phdr; ph < phlimit; ph++) { 1656 switch (ph->p_type) { 1657 1658 case PT_INTERP: 1659 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1660 break; 1661 1662 case PT_LOAD: 1663 if (nsegs == 0) { /* First load segment */ 1664 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); 1665 obj->mapbase = obj->vaddrbase + obj->relocbase; 1666 } else { /* Last load segment */ 1667 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - 1668 obj->vaddrbase; 1669 } 1670 nsegs++; 1671 break; 1672 1673 case PT_DYNAMIC: 1674 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1675 break; 1676 1677 case PT_TLS: 1678 obj->tlsindex = 1; 1679 obj->tlssize = ph->p_memsz; 1680 obj->tlsalign = ph->p_align; 1681 obj->tlsinitsize = ph->p_filesz; 1682 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1683 obj->tlspoffset = ph->p_offset; 1684 break; 1685 1686 case PT_GNU_STACK: 1687 obj->stack_flags = ph->p_flags; 1688 break; 1689 1690 case PT_GNU_RELRO: 1691 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 1692 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) - 1693 rtld_trunc_page(ph->p_vaddr); 1694 break; 1695 1696 case PT_NOTE: 1697 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1698 note_end = note_start + ph->p_filesz; 1699 digest_notes(obj, note_start, note_end); 1700 break; 1701 } 1702 } 1703 if (nsegs < 1) { 1704 _rtld_error("%s: too few PT_LOAD segments", path); 1705 return (NULL); 1706 } 1707 1708 obj->entry = entry; 1709 return (obj); 1710 } 1711 1712 void 1713 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1714 { 1715 const Elf_Note *note; 1716 const char *note_name; 1717 uintptr_t p; 1718 1719 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1720 note = (const Elf_Note *)((const char *)(note + 1) + 1721 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1722 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1723 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1724 note->n_descsz != sizeof(int32_t)) 1725 continue; 1726 if (note->n_type != NT_FREEBSD_ABI_TAG && 1727 note->n_type != NT_FREEBSD_FEATURE_CTL && 1728 note->n_type != NT_FREEBSD_NOINIT_TAG) 1729 continue; 1730 note_name = (const char *)(note + 1); 1731 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1732 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1733 continue; 1734 switch (note->n_type) { 1735 case NT_FREEBSD_ABI_TAG: 1736 /* FreeBSD osrel note */ 1737 p = (uintptr_t)(note + 1); 1738 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1739 obj->osrel = *(const int32_t *)(p); 1740 dbg("note osrel %d", obj->osrel); 1741 break; 1742 case NT_FREEBSD_FEATURE_CTL: 1743 /* FreeBSD ABI feature control note */ 1744 p = (uintptr_t)(note + 1); 1745 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1746 obj->fctl0 = *(const uint32_t *)(p); 1747 dbg("note fctl0 %#x", obj->fctl0); 1748 break; 1749 case NT_FREEBSD_NOINIT_TAG: 1750 /* FreeBSD 'crt does not call init' note */ 1751 obj->crt_no_init = true; 1752 dbg("note crt_no_init"); 1753 break; 1754 } 1755 } 1756 } 1757 1758 static Obj_Entry * 1759 dlcheck(void *handle) 1760 { 1761 Obj_Entry *obj; 1762 1763 TAILQ_FOREACH(obj, &obj_list, next) { 1764 if (obj == (Obj_Entry *) handle) 1765 break; 1766 } 1767 1768 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1769 _rtld_error("Invalid shared object handle %p", handle); 1770 return (NULL); 1771 } 1772 return (obj); 1773 } 1774 1775 /* 1776 * If the given object is already in the donelist, return true. Otherwise 1777 * add the object to the list and return false. 1778 */ 1779 static bool 1780 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1781 { 1782 unsigned int i; 1783 1784 for (i = 0; i < dlp->num_used; i++) 1785 if (dlp->objs[i] == obj) 1786 return (true); 1787 /* 1788 * Our donelist allocation should always be sufficient. But if 1789 * our threads locking isn't working properly, more shared objects 1790 * could have been loaded since we allocated the list. That should 1791 * never happen, but we'll handle it properly just in case it does. 1792 */ 1793 if (dlp->num_used < dlp->num_alloc) 1794 dlp->objs[dlp->num_used++] = obj; 1795 return (false); 1796 } 1797 1798 /* 1799 * SysV hash function for symbol table lookup. It is a slightly optimized 1800 * version of the hash specified by the System V ABI. 1801 */ 1802 Elf32_Word 1803 elf_hash(const char *name) 1804 { 1805 const unsigned char *p = (const unsigned char *)name; 1806 Elf32_Word h = 0; 1807 1808 while (*p != '\0') { 1809 h = (h << 4) + *p++; 1810 h ^= (h >> 24) & 0xf0; 1811 } 1812 return (h & 0x0fffffff); 1813 } 1814 1815 /* 1816 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1817 * unsigned in case it's implemented with a wider type. 1818 */ 1819 static uint32_t 1820 gnu_hash(const char *s) 1821 { 1822 uint32_t h; 1823 unsigned char c; 1824 1825 h = 5381; 1826 for (c = *s; c != '\0'; c = *++s) 1827 h = h * 33 + c; 1828 return (h & 0xffffffff); 1829 } 1830 1831 1832 /* 1833 * Find the library with the given name, and return its full pathname. 1834 * The returned string is dynamically allocated. Generates an error 1835 * message and returns NULL if the library cannot be found. 1836 * 1837 * If the second argument is non-NULL, then it refers to an already- 1838 * loaded shared object, whose library search path will be searched. 1839 * 1840 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1841 * descriptor (which is close-on-exec) will be passed out via the third 1842 * argument. 1843 * 1844 * The search order is: 1845 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1846 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1847 * LD_LIBRARY_PATH 1848 * DT_RUNPATH in the referencing file 1849 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1850 * from list) 1851 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1852 * 1853 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1854 */ 1855 static char * 1856 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1857 { 1858 char *pathname, *refobj_path; 1859 const char *name; 1860 bool nodeflib, objgiven; 1861 1862 objgiven = refobj != NULL; 1863 1864 if (libmap_disable || !objgiven || 1865 (name = lm_find(refobj->path, xname)) == NULL) 1866 name = xname; 1867 1868 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1869 if (name[0] != '/' && !trust) { 1870 _rtld_error("Absolute pathname required " 1871 "for shared object \"%s\"", name); 1872 return (NULL); 1873 } 1874 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1875 __DECONST(char *, name))); 1876 } 1877 1878 dbg(" Searching for \"%s\"", name); 1879 refobj_path = objgiven ? refobj->path : NULL; 1880 1881 /* 1882 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1883 * back to pre-conforming behaviour if user requested so with 1884 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1885 * nodeflib. 1886 */ 1887 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1888 pathname = search_library_path(name, ld_library_path, 1889 refobj_path, fdp); 1890 if (pathname != NULL) 1891 return (pathname); 1892 if (refobj != NULL) { 1893 pathname = search_library_path(name, refobj->rpath, 1894 refobj_path, fdp); 1895 if (pathname != NULL) 1896 return (pathname); 1897 } 1898 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1899 if (pathname != NULL) 1900 return (pathname); 1901 pathname = search_library_path(name, gethints(false), 1902 refobj_path, fdp); 1903 if (pathname != NULL) 1904 return (pathname); 1905 pathname = search_library_path(name, ld_standard_library_path, 1906 refobj_path, fdp); 1907 if (pathname != NULL) 1908 return (pathname); 1909 } else { 1910 nodeflib = objgiven ? refobj->z_nodeflib : false; 1911 if (objgiven) { 1912 pathname = search_library_path(name, refobj->rpath, 1913 refobj->path, fdp); 1914 if (pathname != NULL) 1915 return (pathname); 1916 } 1917 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1918 pathname = search_library_path(name, obj_main->rpath, 1919 refobj_path, fdp); 1920 if (pathname != NULL) 1921 return (pathname); 1922 } 1923 pathname = search_library_path(name, ld_library_path, 1924 refobj_path, fdp); 1925 if (pathname != NULL) 1926 return (pathname); 1927 if (objgiven) { 1928 pathname = search_library_path(name, refobj->runpath, 1929 refobj_path, fdp); 1930 if (pathname != NULL) 1931 return (pathname); 1932 } 1933 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1934 if (pathname != NULL) 1935 return (pathname); 1936 pathname = search_library_path(name, gethints(nodeflib), 1937 refobj_path, fdp); 1938 if (pathname != NULL) 1939 return (pathname); 1940 if (objgiven && !nodeflib) { 1941 pathname = search_library_path(name, 1942 ld_standard_library_path, refobj_path, fdp); 1943 if (pathname != NULL) 1944 return (pathname); 1945 } 1946 } 1947 1948 if (objgiven && refobj->path != NULL) { 1949 _rtld_error("Shared object \"%s\" not found, " 1950 "required by \"%s\"", name, basename(refobj->path)); 1951 } else { 1952 _rtld_error("Shared object \"%s\" not found", name); 1953 } 1954 return (NULL); 1955 } 1956 1957 /* 1958 * Given a symbol number in a referencing object, find the corresponding 1959 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1960 * no definition was found. Returns a pointer to the Obj_Entry of the 1961 * defining object via the reference parameter DEFOBJ_OUT. 1962 */ 1963 const Elf_Sym * 1964 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1965 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1966 RtldLockState *lockstate) 1967 { 1968 const Elf_Sym *ref; 1969 const Elf_Sym *def; 1970 const Obj_Entry *defobj; 1971 const Ver_Entry *ve; 1972 SymLook req; 1973 const char *name; 1974 int res; 1975 1976 /* 1977 * If we have already found this symbol, get the information from 1978 * the cache. 1979 */ 1980 if (symnum >= refobj->dynsymcount) 1981 return (NULL); /* Bad object */ 1982 if (cache != NULL && cache[symnum].sym != NULL) { 1983 *defobj_out = cache[symnum].obj; 1984 return (cache[symnum].sym); 1985 } 1986 1987 ref = refobj->symtab + symnum; 1988 name = refobj->strtab + ref->st_name; 1989 def = NULL; 1990 defobj = NULL; 1991 ve = NULL; 1992 1993 /* 1994 * We don't have to do a full scale lookup if the symbol is local. 1995 * We know it will bind to the instance in this load module; to 1996 * which we already have a pointer (ie ref). By not doing a lookup, 1997 * we not only improve performance, but it also avoids unresolvable 1998 * symbols when local symbols are not in the hash table. This has 1999 * been seen with the ia64 toolchain. 2000 */ 2001 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2002 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2003 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2004 symnum); 2005 } 2006 symlook_init(&req, name); 2007 req.flags = flags; 2008 ve = req.ventry = fetch_ventry(refobj, symnum); 2009 req.lockstate = lockstate; 2010 res = symlook_default(&req, refobj); 2011 if (res == 0) { 2012 def = req.sym_out; 2013 defobj = req.defobj_out; 2014 } 2015 } else { 2016 def = ref; 2017 defobj = refobj; 2018 } 2019 2020 /* 2021 * If we found no definition and the reference is weak, treat the 2022 * symbol as having the value zero. 2023 */ 2024 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2025 def = &sym_zero; 2026 defobj = obj_main; 2027 } 2028 2029 if (def != NULL) { 2030 *defobj_out = defobj; 2031 /* Record the information in the cache to avoid subsequent lookups. */ 2032 if (cache != NULL) { 2033 cache[symnum].sym = def; 2034 cache[symnum].obj = defobj; 2035 } 2036 } else { 2037 if (refobj != &obj_rtld) 2038 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2039 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2040 } 2041 return (def); 2042 } 2043 2044 /* 2045 * Return the search path from the ldconfig hints file, reading it if 2046 * necessary. If nostdlib is true, then the default search paths are 2047 * not added to result. 2048 * 2049 * Returns NULL if there are problems with the hints file, 2050 * or if the search path there is empty. 2051 */ 2052 static const char * 2053 gethints(bool nostdlib) 2054 { 2055 static char *filtered_path; 2056 static const char *hints; 2057 static struct elfhints_hdr hdr; 2058 struct fill_search_info_args sargs, hargs; 2059 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2060 struct dl_serpath *SLPpath, *hintpath; 2061 char *p; 2062 struct stat hint_stat; 2063 unsigned int SLPndx, hintndx, fndx, fcount; 2064 int fd; 2065 size_t flen; 2066 uint32_t dl; 2067 bool skip; 2068 2069 /* First call, read the hints file */ 2070 if (hints == NULL) { 2071 /* Keep from trying again in case the hints file is bad. */ 2072 hints = ""; 2073 2074 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2075 return (NULL); 2076 2077 /* 2078 * Check of hdr.dirlistlen value against type limit 2079 * intends to pacify static analyzers. Further 2080 * paranoia leads to checks that dirlist is fully 2081 * contained in the file range. 2082 */ 2083 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2084 hdr.magic != ELFHINTS_MAGIC || 2085 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2086 fstat(fd, &hint_stat) == -1) { 2087 cleanup1: 2088 close(fd); 2089 hdr.dirlistlen = 0; 2090 return (NULL); 2091 } 2092 dl = hdr.strtab; 2093 if (dl + hdr.dirlist < dl) 2094 goto cleanup1; 2095 dl += hdr.dirlist; 2096 if (dl + hdr.dirlistlen < dl) 2097 goto cleanup1; 2098 dl += hdr.dirlistlen; 2099 if (dl > hint_stat.st_size) 2100 goto cleanup1; 2101 p = xmalloc(hdr.dirlistlen + 1); 2102 if (pread(fd, p, hdr.dirlistlen + 1, 2103 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2104 p[hdr.dirlistlen] != '\0') { 2105 free(p); 2106 goto cleanup1; 2107 } 2108 hints = p; 2109 close(fd); 2110 } 2111 2112 /* 2113 * If caller agreed to receive list which includes the default 2114 * paths, we are done. Otherwise, if we still did not 2115 * calculated filtered result, do it now. 2116 */ 2117 if (!nostdlib) 2118 return (hints[0] != '\0' ? hints : NULL); 2119 if (filtered_path != NULL) 2120 goto filt_ret; 2121 2122 /* 2123 * Obtain the list of all configured search paths, and the 2124 * list of the default paths. 2125 * 2126 * First estimate the size of the results. 2127 */ 2128 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2129 smeta.dls_cnt = 0; 2130 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2131 hmeta.dls_cnt = 0; 2132 2133 sargs.request = RTLD_DI_SERINFOSIZE; 2134 sargs.serinfo = &smeta; 2135 hargs.request = RTLD_DI_SERINFOSIZE; 2136 hargs.serinfo = &hmeta; 2137 2138 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2139 &sargs); 2140 path_enumerate(hints, fill_search_info, NULL, &hargs); 2141 2142 SLPinfo = xmalloc(smeta.dls_size); 2143 hintinfo = xmalloc(hmeta.dls_size); 2144 2145 /* 2146 * Next fetch both sets of paths. 2147 */ 2148 sargs.request = RTLD_DI_SERINFO; 2149 sargs.serinfo = SLPinfo; 2150 sargs.serpath = &SLPinfo->dls_serpath[0]; 2151 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2152 2153 hargs.request = RTLD_DI_SERINFO; 2154 hargs.serinfo = hintinfo; 2155 hargs.serpath = &hintinfo->dls_serpath[0]; 2156 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2157 2158 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2159 &sargs); 2160 path_enumerate(hints, fill_search_info, NULL, &hargs); 2161 2162 /* 2163 * Now calculate the difference between two sets, by excluding 2164 * standard paths from the full set. 2165 */ 2166 fndx = 0; 2167 fcount = 0; 2168 filtered_path = xmalloc(hdr.dirlistlen + 1); 2169 hintpath = &hintinfo->dls_serpath[0]; 2170 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2171 skip = false; 2172 SLPpath = &SLPinfo->dls_serpath[0]; 2173 /* 2174 * Check each standard path against current. 2175 */ 2176 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2177 /* matched, skip the path */ 2178 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2179 skip = true; 2180 break; 2181 } 2182 } 2183 if (skip) 2184 continue; 2185 /* 2186 * Not matched against any standard path, add the path 2187 * to result. Separate consequtive paths with ':'. 2188 */ 2189 if (fcount > 0) { 2190 filtered_path[fndx] = ':'; 2191 fndx++; 2192 } 2193 fcount++; 2194 flen = strlen(hintpath->dls_name); 2195 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2196 fndx += flen; 2197 } 2198 filtered_path[fndx] = '\0'; 2199 2200 free(SLPinfo); 2201 free(hintinfo); 2202 2203 filt_ret: 2204 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2205 } 2206 2207 static void 2208 init_dag(Obj_Entry *root) 2209 { 2210 const Needed_Entry *needed; 2211 const Objlist_Entry *elm; 2212 DoneList donelist; 2213 2214 if (root->dag_inited) 2215 return; 2216 donelist_init(&donelist); 2217 2218 /* Root object belongs to own DAG. */ 2219 objlist_push_tail(&root->dldags, root); 2220 objlist_push_tail(&root->dagmembers, root); 2221 donelist_check(&donelist, root); 2222 2223 /* 2224 * Add dependencies of root object to DAG in breadth order 2225 * by exploiting the fact that each new object get added 2226 * to the tail of the dagmembers list. 2227 */ 2228 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2229 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2230 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2231 continue; 2232 objlist_push_tail(&needed->obj->dldags, root); 2233 objlist_push_tail(&root->dagmembers, needed->obj); 2234 } 2235 } 2236 root->dag_inited = true; 2237 } 2238 2239 static void 2240 init_marker(Obj_Entry *marker) 2241 { 2242 2243 bzero(marker, sizeof(*marker)); 2244 marker->marker = true; 2245 } 2246 2247 Obj_Entry * 2248 globallist_curr(const Obj_Entry *obj) 2249 { 2250 2251 for (;;) { 2252 if (obj == NULL) 2253 return (NULL); 2254 if (!obj->marker) 2255 return (__DECONST(Obj_Entry *, obj)); 2256 obj = TAILQ_PREV(obj, obj_entry_q, next); 2257 } 2258 } 2259 2260 Obj_Entry * 2261 globallist_next(const Obj_Entry *obj) 2262 { 2263 2264 for (;;) { 2265 obj = TAILQ_NEXT(obj, next); 2266 if (obj == NULL) 2267 return (NULL); 2268 if (!obj->marker) 2269 return (__DECONST(Obj_Entry *, obj)); 2270 } 2271 } 2272 2273 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2274 static void 2275 hold_object(Obj_Entry *obj) 2276 { 2277 2278 obj->holdcount++; 2279 } 2280 2281 static void 2282 unhold_object(Obj_Entry *obj) 2283 { 2284 2285 assert(obj->holdcount > 0); 2286 if (--obj->holdcount == 0 && obj->unholdfree) 2287 release_object(obj); 2288 } 2289 2290 static void 2291 process_z(Obj_Entry *root) 2292 { 2293 const Objlist_Entry *elm; 2294 Obj_Entry *obj; 2295 2296 /* 2297 * Walk over object DAG and process every dependent object 2298 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2299 * to grow their own DAG. 2300 * 2301 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2302 * symlook_global() to work. 2303 * 2304 * For DF_1_NODELETE, the DAG should have its reference upped. 2305 */ 2306 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2307 obj = elm->obj; 2308 if (obj == NULL) 2309 continue; 2310 if (obj->z_nodelete && !obj->ref_nodel) { 2311 dbg("obj %s -z nodelete", obj->path); 2312 init_dag(obj); 2313 ref_dag(obj); 2314 obj->ref_nodel = true; 2315 } 2316 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2317 dbg("obj %s -z global", obj->path); 2318 objlist_push_tail(&list_global, obj); 2319 init_dag(obj); 2320 } 2321 } 2322 } 2323 2324 static void 2325 parse_rtld_phdr(Obj_Entry *obj) 2326 { 2327 const Elf_Phdr *ph; 2328 Elf_Addr note_start, note_end; 2329 2330 obj->stack_flags = PF_X | PF_R | PF_W; 2331 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2332 obj->phsize; ph++) { 2333 switch (ph->p_type) { 2334 case PT_GNU_STACK: 2335 obj->stack_flags = ph->p_flags; 2336 break; 2337 case PT_GNU_RELRO: 2338 obj->relro_page = obj->relocbase + 2339 rtld_trunc_page(ph->p_vaddr); 2340 obj->relro_size = rtld_round_page(ph->p_memsz); 2341 break; 2342 case PT_NOTE: 2343 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2344 note_end = note_start + ph->p_filesz; 2345 digest_notes(obj, note_start, note_end); 2346 break; 2347 } 2348 } 2349 } 2350 2351 /* 2352 * Initialize the dynamic linker. The argument is the address at which 2353 * the dynamic linker has been mapped into memory. The primary task of 2354 * this function is to relocate the dynamic linker. 2355 */ 2356 static void 2357 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2358 { 2359 Obj_Entry objtmp; /* Temporary rtld object */ 2360 const Elf_Ehdr *ehdr; 2361 const Elf_Dyn *dyn_rpath; 2362 const Elf_Dyn *dyn_soname; 2363 const Elf_Dyn *dyn_runpath; 2364 2365 #ifdef RTLD_INIT_PAGESIZES_EARLY 2366 /* The page size is required by the dynamic memory allocator. */ 2367 init_pagesizes(aux_info); 2368 #endif 2369 2370 /* 2371 * Conjure up an Obj_Entry structure for the dynamic linker. 2372 * 2373 * The "path" member can't be initialized yet because string constants 2374 * cannot yet be accessed. Below we will set it correctly. 2375 */ 2376 memset(&objtmp, 0, sizeof(objtmp)); 2377 objtmp.path = NULL; 2378 objtmp.rtld = true; 2379 objtmp.mapbase = mapbase; 2380 #ifdef PIC 2381 objtmp.relocbase = mapbase; 2382 #endif 2383 2384 objtmp.dynamic = rtld_dynamic(&objtmp); 2385 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2386 assert(objtmp.needed == NULL); 2387 assert(!objtmp.textrel); 2388 /* 2389 * Temporarily put the dynamic linker entry into the object list, so 2390 * that symbols can be found. 2391 */ 2392 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2393 2394 ehdr = (Elf_Ehdr *)mapbase; 2395 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2396 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2397 2398 /* Initialize the object list. */ 2399 TAILQ_INIT(&obj_list); 2400 2401 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2402 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2403 2404 #ifndef RTLD_INIT_PAGESIZES_EARLY 2405 /* The page size is required by the dynamic memory allocator. */ 2406 init_pagesizes(aux_info); 2407 #endif 2408 2409 if (aux_info[AT_OSRELDATE] != NULL) 2410 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2411 2412 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2413 2414 /* Replace the path with a dynamically allocated copy. */ 2415 obj_rtld.path = xstrdup(ld_path_rtld); 2416 2417 parse_rtld_phdr(&obj_rtld); 2418 if (obj_enforce_relro(&obj_rtld) == -1) 2419 rtld_die(); 2420 2421 r_debug.r_version = R_DEBUG_VERSION; 2422 r_debug.r_brk = r_debug_state; 2423 r_debug.r_state = RT_CONSISTENT; 2424 r_debug.r_ldbase = obj_rtld.relocbase; 2425 } 2426 2427 /* 2428 * Retrieve the array of supported page sizes. The kernel provides the page 2429 * sizes in increasing order. 2430 */ 2431 static void 2432 init_pagesizes(Elf_Auxinfo **aux_info) 2433 { 2434 static size_t psa[MAXPAGESIZES]; 2435 int mib[2]; 2436 size_t len, size; 2437 2438 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2439 NULL) { 2440 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2441 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2442 } else { 2443 len = 2; 2444 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2445 size = sizeof(psa); 2446 else { 2447 /* As a fallback, retrieve the base page size. */ 2448 size = sizeof(psa[0]); 2449 if (aux_info[AT_PAGESZ] != NULL) { 2450 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2451 goto psa_filled; 2452 } else { 2453 mib[0] = CTL_HW; 2454 mib[1] = HW_PAGESIZE; 2455 len = 2; 2456 } 2457 } 2458 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2459 _rtld_error("sysctl for hw.pagesize(s) failed"); 2460 rtld_die(); 2461 } 2462 psa_filled: 2463 pagesizes = psa; 2464 } 2465 npagesizes = size / sizeof(pagesizes[0]); 2466 /* Discard any invalid entries at the end of the array. */ 2467 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2468 npagesizes--; 2469 2470 page_size = pagesizes[0]; 2471 } 2472 2473 /* 2474 * Add the init functions from a needed object list (and its recursive 2475 * needed objects) to "list". This is not used directly; it is a helper 2476 * function for initlist_add_objects(). The write lock must be held 2477 * when this function is called. 2478 */ 2479 static void 2480 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2481 { 2482 /* Recursively process the successor needed objects. */ 2483 if (needed->next != NULL) 2484 initlist_add_neededs(needed->next, list); 2485 2486 /* Process the current needed object. */ 2487 if (needed->obj != NULL) 2488 initlist_add_objects(needed->obj, needed->obj, list); 2489 } 2490 2491 /* 2492 * Scan all of the DAGs rooted in the range of objects from "obj" to 2493 * "tail" and add their init functions to "list". This recurses over 2494 * the DAGs and ensure the proper init ordering such that each object's 2495 * needed libraries are initialized before the object itself. At the 2496 * same time, this function adds the objects to the global finalization 2497 * list "list_fini" in the opposite order. The write lock must be 2498 * held when this function is called. 2499 */ 2500 static void 2501 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2502 { 2503 Obj_Entry *nobj; 2504 2505 if (obj->init_scanned || obj->init_done) 2506 return; 2507 obj->init_scanned = true; 2508 2509 /* Recursively process the successor objects. */ 2510 nobj = globallist_next(obj); 2511 if (nobj != NULL && obj != tail) 2512 initlist_add_objects(nobj, tail, list); 2513 2514 /* Recursively process the needed objects. */ 2515 if (obj->needed != NULL) 2516 initlist_add_neededs(obj->needed, list); 2517 if (obj->needed_filtees != NULL) 2518 initlist_add_neededs(obj->needed_filtees, list); 2519 if (obj->needed_aux_filtees != NULL) 2520 initlist_add_neededs(obj->needed_aux_filtees, list); 2521 2522 /* Add the object to the init list. */ 2523 objlist_push_tail(list, obj); 2524 2525 /* Add the object to the global fini list in the reverse order. */ 2526 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2527 && !obj->on_fini_list) { 2528 objlist_push_head(&list_fini, obj); 2529 obj->on_fini_list = true; 2530 } 2531 } 2532 2533 static void 2534 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2535 { 2536 Needed_Entry *needed, *needed1; 2537 2538 for (needed = n; needed != NULL; needed = needed->next) { 2539 if (needed->obj != NULL) { 2540 dlclose_locked(needed->obj, lockstate); 2541 needed->obj = NULL; 2542 } 2543 } 2544 for (needed = n; needed != NULL; needed = needed1) { 2545 needed1 = needed->next; 2546 free(needed); 2547 } 2548 } 2549 2550 static void 2551 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2552 { 2553 2554 free_needed_filtees(obj->needed_filtees, lockstate); 2555 obj->needed_filtees = NULL; 2556 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2557 obj->needed_aux_filtees = NULL; 2558 obj->filtees_loaded = false; 2559 } 2560 2561 static void 2562 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2563 RtldLockState *lockstate) 2564 { 2565 2566 for (; needed != NULL; needed = needed->next) { 2567 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2568 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2569 RTLD_LOCAL, lockstate); 2570 } 2571 } 2572 2573 static void 2574 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2575 { 2576 2577 lock_restart_for_upgrade(lockstate); 2578 if (!obj->filtees_loaded) { 2579 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2580 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2581 obj->filtees_loaded = true; 2582 } 2583 } 2584 2585 static int 2586 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2587 { 2588 Obj_Entry *obj1; 2589 2590 for (; needed != NULL; needed = needed->next) { 2591 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2592 flags & ~RTLD_LO_NOLOAD); 2593 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2594 return (-1); 2595 } 2596 return (0); 2597 } 2598 2599 /* 2600 * Given a shared object, traverse its list of needed objects, and load 2601 * each of them. Returns 0 on success. Generates an error message and 2602 * returns -1 on failure. 2603 */ 2604 static int 2605 load_needed_objects(Obj_Entry *first, int flags) 2606 { 2607 Obj_Entry *obj; 2608 2609 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2610 if (obj->marker) 2611 continue; 2612 if (process_needed(obj, obj->needed, flags) == -1) 2613 return (-1); 2614 } 2615 return (0); 2616 } 2617 2618 static int 2619 load_preload_objects(const char *penv, bool isfd) 2620 { 2621 Obj_Entry *obj; 2622 const char *name; 2623 size_t len; 2624 char savech, *p, *psave; 2625 int fd; 2626 static const char delim[] = " \t:;"; 2627 2628 if (penv == NULL) 2629 return (0); 2630 2631 p = psave = xstrdup(penv); 2632 p += strspn(p, delim); 2633 while (*p != '\0') { 2634 len = strcspn(p, delim); 2635 2636 savech = p[len]; 2637 p[len] = '\0'; 2638 if (isfd) { 2639 name = NULL; 2640 fd = parse_integer(p); 2641 if (fd == -1) { 2642 free(psave); 2643 return (-1); 2644 } 2645 } else { 2646 name = p; 2647 fd = -1; 2648 } 2649 2650 obj = load_object(name, fd, NULL, 0); 2651 if (obj == NULL) { 2652 free(psave); 2653 return (-1); /* XXX - cleanup */ 2654 } 2655 obj->z_interpose = true; 2656 p[len] = savech; 2657 p += len; 2658 p += strspn(p, delim); 2659 } 2660 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2661 2662 free(psave); 2663 return (0); 2664 } 2665 2666 static const char * 2667 printable_path(const char *path) 2668 { 2669 2670 return (path == NULL ? "<unknown>" : path); 2671 } 2672 2673 /* 2674 * Load a shared object into memory, if it is not already loaded. The 2675 * object may be specified by name or by user-supplied file descriptor 2676 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2677 * duplicate is. 2678 * 2679 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2680 * on failure. 2681 */ 2682 static Obj_Entry * 2683 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2684 { 2685 Obj_Entry *obj; 2686 int fd; 2687 struct stat sb; 2688 char *path; 2689 2690 fd = -1; 2691 if (name != NULL) { 2692 TAILQ_FOREACH(obj, &obj_list, next) { 2693 if (obj->marker || obj->doomed) 2694 continue; 2695 if (object_match_name(obj, name)) 2696 return (obj); 2697 } 2698 2699 path = find_library(name, refobj, &fd); 2700 if (path == NULL) 2701 return (NULL); 2702 } else 2703 path = NULL; 2704 2705 if (fd >= 0) { 2706 /* 2707 * search_library_pathfds() opens a fresh file descriptor for the 2708 * library, so there is no need to dup(). 2709 */ 2710 } else if (fd_u == -1) { 2711 /* 2712 * If we didn't find a match by pathname, or the name is not 2713 * supplied, open the file and check again by device and inode. 2714 * This avoids false mismatches caused by multiple links or ".." 2715 * in pathnames. 2716 * 2717 * To avoid a race, we open the file and use fstat() rather than 2718 * using stat(). 2719 */ 2720 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2721 _rtld_error("Cannot open \"%s\"", path); 2722 free(path); 2723 return (NULL); 2724 } 2725 } else { 2726 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2727 if (fd == -1) { 2728 _rtld_error("Cannot dup fd"); 2729 free(path); 2730 return (NULL); 2731 } 2732 } 2733 if (fstat(fd, &sb) == -1) { 2734 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2735 close(fd); 2736 free(path); 2737 return (NULL); 2738 } 2739 TAILQ_FOREACH(obj, &obj_list, next) { 2740 if (obj->marker || obj->doomed) 2741 continue; 2742 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2743 break; 2744 } 2745 if (obj != NULL && name != NULL) { 2746 object_add_name(obj, name); 2747 free(path); 2748 close(fd); 2749 return (obj); 2750 } 2751 if (flags & RTLD_LO_NOLOAD) { 2752 free(path); 2753 close(fd); 2754 return (NULL); 2755 } 2756 2757 /* First use of this object, so we must map it in */ 2758 obj = do_load_object(fd, name, path, &sb, flags); 2759 if (obj == NULL) 2760 free(path); 2761 close(fd); 2762 2763 return (obj); 2764 } 2765 2766 static Obj_Entry * 2767 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2768 int flags) 2769 { 2770 Obj_Entry *obj; 2771 struct statfs fs; 2772 2773 /* 2774 * First, make sure that environment variables haven't been 2775 * used to circumvent the noexec flag on a filesystem. 2776 * We ignore fstatfs(2) failures, since fd might reference 2777 * not a file, e.g. shmfd. 2778 */ 2779 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2780 (fs.f_flags & MNT_NOEXEC) != 0) { 2781 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2782 return (NULL); 2783 } 2784 2785 dbg("loading \"%s\"", printable_path(path)); 2786 obj = map_object(fd, printable_path(path), sbp); 2787 if (obj == NULL) 2788 return (NULL); 2789 2790 /* 2791 * If DT_SONAME is present in the object, digest_dynamic2 already 2792 * added it to the object names. 2793 */ 2794 if (name != NULL) 2795 object_add_name(obj, name); 2796 obj->path = path; 2797 if (!digest_dynamic(obj, 0)) 2798 goto errp; 2799 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2800 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2801 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2802 dbg("refusing to load PIE executable \"%s\"", obj->path); 2803 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2804 goto errp; 2805 } 2806 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2807 RTLD_LO_DLOPEN) { 2808 dbg("refusing to load non-loadable \"%s\"", obj->path); 2809 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2810 goto errp; 2811 } 2812 2813 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2814 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2815 obj_count++; 2816 obj_loads++; 2817 linkmap_add(obj); /* for GDB & dlinfo() */ 2818 max_stack_flags |= obj->stack_flags; 2819 2820 dbg(" %p .. %p: %s", obj->mapbase, 2821 obj->mapbase + obj->mapsize - 1, obj->path); 2822 if (obj->textrel) 2823 dbg(" WARNING: %s has impure text", obj->path); 2824 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2825 obj->path); 2826 2827 return (obj); 2828 2829 errp: 2830 munmap(obj->mapbase, obj->mapsize); 2831 obj_free(obj); 2832 return (NULL); 2833 } 2834 2835 static int 2836 load_kpreload(const void *addr) 2837 { 2838 Obj_Entry *obj; 2839 const Elf_Ehdr *ehdr; 2840 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2841 static const char kname[] = "[vdso]"; 2842 2843 ehdr = addr; 2844 if (!check_elf_headers(ehdr, "kpreload")) 2845 return (-1); 2846 obj = obj_new(); 2847 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2848 obj->phdr = phdr; 2849 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2850 phlimit = phdr + ehdr->e_phnum; 2851 seg0 = segn = NULL; 2852 2853 for (; phdr < phlimit; phdr++) { 2854 switch (phdr->p_type) { 2855 case PT_DYNAMIC: 2856 phdyn = phdr; 2857 break; 2858 case PT_GNU_STACK: 2859 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2860 obj->stack_flags = phdr->p_flags; 2861 break; 2862 case PT_LOAD: 2863 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2864 seg0 = phdr; 2865 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2866 phdr->p_vaddr + phdr->p_memsz) 2867 segn = phdr; 2868 break; 2869 } 2870 } 2871 2872 obj->mapbase = __DECONST(caddr_t, addr); 2873 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2874 obj->vaddrbase = 0; 2875 obj->relocbase = obj->mapbase; 2876 2877 object_add_name(obj, kname); 2878 obj->path = xstrdup(kname); 2879 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2880 2881 if (!digest_dynamic(obj, 0)) { 2882 obj_free(obj); 2883 return (-1); 2884 } 2885 2886 /* 2887 * We assume that kernel-preloaded object does not need 2888 * relocation. It is currently written into read-only page, 2889 * handling relocations would mean we need to allocate at 2890 * least one additional page per AS. 2891 */ 2892 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2893 obj->path, obj->mapbase, obj->phdr, seg0, 2894 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2895 2896 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2897 obj_count++; 2898 obj_loads++; 2899 linkmap_add(obj); /* for GDB & dlinfo() */ 2900 max_stack_flags |= obj->stack_flags; 2901 2902 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2903 return (0); 2904 } 2905 2906 Obj_Entry * 2907 obj_from_addr(const void *addr) 2908 { 2909 Obj_Entry *obj; 2910 2911 TAILQ_FOREACH(obj, &obj_list, next) { 2912 if (obj->marker) 2913 continue; 2914 if (addr < (void *) obj->mapbase) 2915 continue; 2916 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2917 return obj; 2918 } 2919 return (NULL); 2920 } 2921 2922 static void 2923 preinit_main(void) 2924 { 2925 Elf_Addr *preinit_addr; 2926 int index; 2927 2928 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2929 if (preinit_addr == NULL) 2930 return; 2931 2932 for (index = 0; index < obj_main->preinit_array_num; index++) { 2933 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2934 dbg("calling preinit function for %s at %p", obj_main->path, 2935 (void *)preinit_addr[index]); 2936 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2937 0, 0, obj_main->path); 2938 call_init_pointer(obj_main, preinit_addr[index]); 2939 } 2940 } 2941 } 2942 2943 /* 2944 * Call the finalization functions for each of the objects in "list" 2945 * belonging to the DAG of "root" and referenced once. If NULL "root" 2946 * is specified, every finalization function will be called regardless 2947 * of the reference count and the list elements won't be freed. All of 2948 * the objects are expected to have non-NULL fini functions. 2949 */ 2950 static void 2951 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2952 { 2953 Objlist_Entry *elm; 2954 struct dlerror_save *saved_msg; 2955 Elf_Addr *fini_addr; 2956 int index; 2957 2958 assert(root == NULL || root->refcount == 1); 2959 2960 if (root != NULL) 2961 root->doomed = true; 2962 2963 /* 2964 * Preserve the current error message since a fini function might 2965 * call into the dynamic linker and overwrite it. 2966 */ 2967 saved_msg = errmsg_save(); 2968 do { 2969 STAILQ_FOREACH(elm, list, link) { 2970 if (root != NULL && (elm->obj->refcount != 1 || 2971 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2972 continue; 2973 /* Remove object from fini list to prevent recursive invocation. */ 2974 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2975 /* Ensure that new references cannot be acquired. */ 2976 elm->obj->doomed = true; 2977 2978 hold_object(elm->obj); 2979 lock_release(rtld_bind_lock, lockstate); 2980 /* 2981 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2982 * When this happens, DT_FINI_ARRAY is processed first. 2983 */ 2984 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2985 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2986 for (index = elm->obj->fini_array_num - 1; index >= 0; 2987 index--) { 2988 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2989 dbg("calling fini function for %s at %p", 2990 elm->obj->path, (void *)fini_addr[index]); 2991 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2992 (void *)fini_addr[index], 0, 0, elm->obj->path); 2993 call_initfini_pointer(elm->obj, fini_addr[index]); 2994 } 2995 } 2996 } 2997 if (elm->obj->fini != (Elf_Addr)NULL) { 2998 dbg("calling fini function for %s at %p", elm->obj->path, 2999 (void *)elm->obj->fini); 3000 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3001 0, 0, elm->obj->path); 3002 call_initfini_pointer(elm->obj, elm->obj->fini); 3003 } 3004 wlock_acquire(rtld_bind_lock, lockstate); 3005 unhold_object(elm->obj); 3006 /* No need to free anything if process is going down. */ 3007 if (root != NULL) 3008 free(elm); 3009 /* 3010 * We must restart the list traversal after every fini call 3011 * because a dlclose() call from the fini function or from 3012 * another thread might have modified the reference counts. 3013 */ 3014 break; 3015 } 3016 } while (elm != NULL); 3017 errmsg_restore(saved_msg); 3018 } 3019 3020 /* 3021 * Call the initialization functions for each of the objects in 3022 * "list". All of the objects are expected to have non-NULL init 3023 * functions. 3024 */ 3025 static void 3026 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3027 { 3028 Objlist_Entry *elm; 3029 Obj_Entry *obj; 3030 struct dlerror_save *saved_msg; 3031 Elf_Addr *init_addr; 3032 void (*reg)(void (*)(void)); 3033 int index; 3034 3035 /* 3036 * Clean init_scanned flag so that objects can be rechecked and 3037 * possibly initialized earlier if any of vectors called below 3038 * cause the change by using dlopen. 3039 */ 3040 TAILQ_FOREACH(obj, &obj_list, next) { 3041 if (obj->marker) 3042 continue; 3043 obj->init_scanned = false; 3044 } 3045 3046 /* 3047 * Preserve the current error message since an init function might 3048 * call into the dynamic linker and overwrite it. 3049 */ 3050 saved_msg = errmsg_save(); 3051 STAILQ_FOREACH(elm, list, link) { 3052 if (elm->obj->init_done) /* Initialized early. */ 3053 continue; 3054 /* 3055 * Race: other thread might try to use this object before current 3056 * one completes the initialization. Not much can be done here 3057 * without better locking. 3058 */ 3059 elm->obj->init_done = true; 3060 hold_object(elm->obj); 3061 reg = NULL; 3062 if (elm->obj == obj_main && obj_main->crt_no_init) { 3063 reg = (void (*)(void (*)(void)))get_program_var_addr( 3064 "__libc_atexit", lockstate); 3065 } 3066 lock_release(rtld_bind_lock, lockstate); 3067 if (reg != NULL) { 3068 reg(rtld_exit); 3069 rtld_exit_ptr = rtld_nop_exit; 3070 } 3071 3072 /* 3073 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3074 * When this happens, DT_INIT is processed first. 3075 */ 3076 if (elm->obj->init != (Elf_Addr)NULL) { 3077 dbg("calling init function for %s at %p", elm->obj->path, 3078 (void *)elm->obj->init); 3079 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3080 0, 0, elm->obj->path); 3081 call_init_pointer(elm->obj, elm->obj->init); 3082 } 3083 init_addr = (Elf_Addr *)elm->obj->init_array; 3084 if (init_addr != NULL) { 3085 for (index = 0; index < elm->obj->init_array_num; index++) { 3086 if (init_addr[index] != 0 && init_addr[index] != 1) { 3087 dbg("calling init function for %s at %p", elm->obj->path, 3088 (void *)init_addr[index]); 3089 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3090 (void *)init_addr[index], 0, 0, elm->obj->path); 3091 call_init_pointer(elm->obj, init_addr[index]); 3092 } 3093 } 3094 } 3095 wlock_acquire(rtld_bind_lock, lockstate); 3096 unhold_object(elm->obj); 3097 } 3098 errmsg_restore(saved_msg); 3099 } 3100 3101 static void 3102 objlist_clear(Objlist *list) 3103 { 3104 Objlist_Entry *elm; 3105 3106 while (!STAILQ_EMPTY(list)) { 3107 elm = STAILQ_FIRST(list); 3108 STAILQ_REMOVE_HEAD(list, link); 3109 free(elm); 3110 } 3111 } 3112 3113 static Objlist_Entry * 3114 objlist_find(Objlist *list, const Obj_Entry *obj) 3115 { 3116 Objlist_Entry *elm; 3117 3118 STAILQ_FOREACH(elm, list, link) 3119 if (elm->obj == obj) 3120 return elm; 3121 return (NULL); 3122 } 3123 3124 static void 3125 objlist_init(Objlist *list) 3126 { 3127 STAILQ_INIT(list); 3128 } 3129 3130 static void 3131 objlist_push_head(Objlist *list, Obj_Entry *obj) 3132 { 3133 Objlist_Entry *elm; 3134 3135 elm = NEW(Objlist_Entry); 3136 elm->obj = obj; 3137 STAILQ_INSERT_HEAD(list, elm, link); 3138 } 3139 3140 static void 3141 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3142 { 3143 Objlist_Entry *elm; 3144 3145 elm = NEW(Objlist_Entry); 3146 elm->obj = obj; 3147 STAILQ_INSERT_TAIL(list, elm, link); 3148 } 3149 3150 static void 3151 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3152 { 3153 Objlist_Entry *elm, *listelm; 3154 3155 STAILQ_FOREACH(listelm, list, link) { 3156 if (listelm->obj == listobj) 3157 break; 3158 } 3159 elm = NEW(Objlist_Entry); 3160 elm->obj = obj; 3161 if (listelm != NULL) 3162 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3163 else 3164 STAILQ_INSERT_TAIL(list, elm, link); 3165 } 3166 3167 static void 3168 objlist_remove(Objlist *list, Obj_Entry *obj) 3169 { 3170 Objlist_Entry *elm; 3171 3172 if ((elm = objlist_find(list, obj)) != NULL) { 3173 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3174 free(elm); 3175 } 3176 } 3177 3178 /* 3179 * Relocate dag rooted in the specified object. 3180 * Returns 0 on success, or -1 on failure. 3181 */ 3182 3183 static int 3184 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3185 int flags, RtldLockState *lockstate) 3186 { 3187 Objlist_Entry *elm; 3188 int error; 3189 3190 error = 0; 3191 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3192 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3193 lockstate); 3194 if (error == -1) 3195 break; 3196 } 3197 return (error); 3198 } 3199 3200 /* 3201 * Prepare for, or clean after, relocating an object marked with 3202 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3203 * segments are remapped read-write. After relocations are done, the 3204 * segment's permissions are returned back to the modes specified in 3205 * the phdrs. If any relocation happened, or always for wired 3206 * program, COW is triggered. 3207 */ 3208 static int 3209 reloc_textrel_prot(Obj_Entry *obj, bool before) 3210 { 3211 const Elf_Phdr *ph; 3212 void *base; 3213 size_t l, sz; 3214 int prot; 3215 3216 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3217 l--, ph++) { 3218 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3219 continue; 3220 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3221 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3222 rtld_trunc_page(ph->p_vaddr); 3223 prot = before ? (PROT_READ | PROT_WRITE) : 3224 convert_prot(ph->p_flags); 3225 if (mprotect(base, sz, prot) == -1) { 3226 _rtld_error("%s: Cannot write-%sable text segment: %s", 3227 obj->path, before ? "en" : "dis", 3228 rtld_strerror(errno)); 3229 return (-1); 3230 } 3231 } 3232 return (0); 3233 } 3234 3235 /* Process RELR relative relocations. */ 3236 static void 3237 reloc_relr(Obj_Entry *obj) 3238 { 3239 const Elf_Relr *relr, *relrlim; 3240 Elf_Addr *where; 3241 3242 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3243 for (relr = obj->relr; relr < relrlim; relr++) { 3244 Elf_Relr entry = *relr; 3245 3246 if ((entry & 1) == 0) { 3247 where = (Elf_Addr *)(obj->relocbase + entry); 3248 *where++ += (Elf_Addr)obj->relocbase; 3249 } else { 3250 for (long i = 0; (entry >>= 1) != 0; i++) 3251 if ((entry & 1) != 0) 3252 where[i] += (Elf_Addr)obj->relocbase; 3253 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3254 } 3255 } 3256 } 3257 3258 /* 3259 * Relocate single object. 3260 * Returns 0 on success, or -1 on failure. 3261 */ 3262 static int 3263 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3264 int flags, RtldLockState *lockstate) 3265 { 3266 3267 if (obj->relocated) 3268 return (0); 3269 obj->relocated = true; 3270 if (obj != rtldobj) 3271 dbg("relocating \"%s\"", obj->path); 3272 3273 if (obj->symtab == NULL || obj->strtab == NULL || 3274 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3275 dbg("object %s has no run-time symbol table", obj->path); 3276 3277 /* There are relocations to the write-protected text segment. */ 3278 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3279 return (-1); 3280 3281 /* Process the non-PLT non-IFUNC relocations. */ 3282 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3283 return (-1); 3284 reloc_relr(obj); 3285 3286 /* Re-protected the text segment. */ 3287 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3288 return (-1); 3289 3290 /* Set the special PLT or GOT entries. */ 3291 init_pltgot(obj); 3292 3293 /* Process the PLT relocations. */ 3294 if (reloc_plt(obj, flags, lockstate) == -1) 3295 return (-1); 3296 /* Relocate the jump slots if we are doing immediate binding. */ 3297 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3298 lockstate) == -1) 3299 return (-1); 3300 3301 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3302 return (-1); 3303 3304 /* 3305 * Set up the magic number and version in the Obj_Entry. These 3306 * were checked in the crt1.o from the original ElfKit, so we 3307 * set them for backward compatibility. 3308 */ 3309 obj->magic = RTLD_MAGIC; 3310 obj->version = RTLD_VERSION; 3311 3312 return (0); 3313 } 3314 3315 /* 3316 * Relocate newly-loaded shared objects. The argument is a pointer to 3317 * the Obj_Entry for the first such object. All objects from the first 3318 * to the end of the list of objects are relocated. Returns 0 on success, 3319 * or -1 on failure. 3320 */ 3321 static int 3322 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3323 int flags, RtldLockState *lockstate) 3324 { 3325 Obj_Entry *obj; 3326 int error; 3327 3328 for (error = 0, obj = first; obj != NULL; 3329 obj = TAILQ_NEXT(obj, next)) { 3330 if (obj->marker) 3331 continue; 3332 error = relocate_object(obj, bind_now, rtldobj, flags, 3333 lockstate); 3334 if (error == -1) 3335 break; 3336 } 3337 return (error); 3338 } 3339 3340 /* 3341 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3342 * referencing STT_GNU_IFUNC symbols is postponed till the other 3343 * relocations are done. The indirect functions specified as 3344 * ifunc are allowed to call other symbols, so we need to have 3345 * objects relocated before asking for resolution from indirects. 3346 * 3347 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3348 * instead of the usual lazy handling of PLT slots. It is 3349 * consistent with how GNU does it. 3350 */ 3351 static int 3352 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3353 RtldLockState *lockstate) 3354 { 3355 3356 if (obj->ifuncs_resolved) 3357 return (0); 3358 obj->ifuncs_resolved = true; 3359 if (!obj->irelative && !obj->irelative_nonplt && 3360 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3361 !obj->non_plt_gnu_ifunc) 3362 return (0); 3363 if (obj_disable_relro(obj) == -1 || 3364 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3365 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3366 lockstate) == -1) || 3367 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3368 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3369 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3370 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3371 obj_enforce_relro(obj) == -1) 3372 return (-1); 3373 return (0); 3374 } 3375 3376 static int 3377 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3378 RtldLockState *lockstate) 3379 { 3380 Objlist_Entry *elm; 3381 Obj_Entry *obj; 3382 3383 STAILQ_FOREACH(elm, list, link) { 3384 obj = elm->obj; 3385 if (obj->marker) 3386 continue; 3387 if (resolve_object_ifunc(obj, bind_now, flags, 3388 lockstate) == -1) 3389 return (-1); 3390 } 3391 return (0); 3392 } 3393 3394 /* 3395 * Cleanup procedure. It will be called (by the atexit mechanism) just 3396 * before the process exits. 3397 */ 3398 static void 3399 rtld_exit(void) 3400 { 3401 RtldLockState lockstate; 3402 3403 wlock_acquire(rtld_bind_lock, &lockstate); 3404 dbg("rtld_exit()"); 3405 objlist_call_fini(&list_fini, NULL, &lockstate); 3406 /* No need to remove the items from the list, since we are exiting. */ 3407 if (!libmap_disable) 3408 lm_fini(); 3409 lock_release(rtld_bind_lock, &lockstate); 3410 } 3411 3412 static void 3413 rtld_nop_exit(void) 3414 { 3415 } 3416 3417 /* 3418 * Iterate over a search path, translate each element, and invoke the 3419 * callback on the result. 3420 */ 3421 static void * 3422 path_enumerate(const char *path, path_enum_proc callback, 3423 const char *refobj_path, void *arg) 3424 { 3425 const char *trans; 3426 if (path == NULL) 3427 return (NULL); 3428 3429 path += strspn(path, ":;"); 3430 while (*path != '\0') { 3431 size_t len; 3432 char *res; 3433 3434 len = strcspn(path, ":;"); 3435 trans = lm_findn(refobj_path, path, len); 3436 if (trans) 3437 res = callback(trans, strlen(trans), arg); 3438 else 3439 res = callback(path, len, arg); 3440 3441 if (res != NULL) 3442 return (res); 3443 3444 path += len; 3445 path += strspn(path, ":;"); 3446 } 3447 3448 return (NULL); 3449 } 3450 3451 struct try_library_args { 3452 const char *name; 3453 size_t namelen; 3454 char *buffer; 3455 size_t buflen; 3456 int fd; 3457 }; 3458 3459 static void * 3460 try_library_path(const char *dir, size_t dirlen, void *param) 3461 { 3462 struct try_library_args *arg; 3463 int fd; 3464 3465 arg = param; 3466 if (*dir == '/' || trust) { 3467 char *pathname; 3468 3469 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3470 return (NULL); 3471 3472 pathname = arg->buffer; 3473 strncpy(pathname, dir, dirlen); 3474 pathname[dirlen] = '/'; 3475 strcpy(pathname + dirlen + 1, arg->name); 3476 3477 dbg(" Trying \"%s\"", pathname); 3478 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3479 if (fd >= 0) { 3480 dbg(" Opened \"%s\", fd %d", pathname, fd); 3481 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3482 strcpy(pathname, arg->buffer); 3483 arg->fd = fd; 3484 return (pathname); 3485 } else { 3486 dbg(" Failed to open \"%s\": %s", 3487 pathname, rtld_strerror(errno)); 3488 } 3489 } 3490 return (NULL); 3491 } 3492 3493 static char * 3494 search_library_path(const char *name, const char *path, 3495 const char *refobj_path, int *fdp) 3496 { 3497 char *p; 3498 struct try_library_args arg; 3499 3500 if (path == NULL) 3501 return (NULL); 3502 3503 arg.name = name; 3504 arg.namelen = strlen(name); 3505 arg.buffer = xmalloc(PATH_MAX); 3506 arg.buflen = PATH_MAX; 3507 arg.fd = -1; 3508 3509 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3510 *fdp = arg.fd; 3511 3512 free(arg.buffer); 3513 3514 return (p); 3515 } 3516 3517 3518 /* 3519 * Finds the library with the given name using the directory descriptors 3520 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3521 * 3522 * Returns a freshly-opened close-on-exec file descriptor for the library, 3523 * or -1 if the library cannot be found. 3524 */ 3525 static char * 3526 search_library_pathfds(const char *name, const char *path, int *fdp) 3527 { 3528 char *envcopy, *fdstr, *found, *last_token; 3529 size_t len; 3530 int dirfd, fd; 3531 3532 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3533 3534 /* Don't load from user-specified libdirs into setuid binaries. */ 3535 if (!trust) 3536 return (NULL); 3537 3538 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3539 if (path == NULL) 3540 return (NULL); 3541 3542 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3543 if (name[0] == '/') { 3544 dbg("Absolute path (%s) passed to %s", name, __func__); 3545 return (NULL); 3546 } 3547 3548 /* 3549 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3550 * copy of the path, as strtok_r rewrites separator tokens 3551 * with '\0'. 3552 */ 3553 found = NULL; 3554 envcopy = xstrdup(path); 3555 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3556 fdstr = strtok_r(NULL, ":", &last_token)) { 3557 dirfd = parse_integer(fdstr); 3558 if (dirfd < 0) { 3559 _rtld_error("failed to parse directory FD: '%s'", 3560 fdstr); 3561 break; 3562 } 3563 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3564 if (fd >= 0) { 3565 *fdp = fd; 3566 len = strlen(fdstr) + strlen(name) + 3; 3567 found = xmalloc(len); 3568 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3569 _rtld_error("error generating '%d/%s'", 3570 dirfd, name); 3571 rtld_die(); 3572 } 3573 dbg("open('%s') => %d", found, fd); 3574 break; 3575 } 3576 } 3577 free(envcopy); 3578 3579 return (found); 3580 } 3581 3582 3583 int 3584 dlclose(void *handle) 3585 { 3586 RtldLockState lockstate; 3587 int error; 3588 3589 wlock_acquire(rtld_bind_lock, &lockstate); 3590 error = dlclose_locked(handle, &lockstate); 3591 lock_release(rtld_bind_lock, &lockstate); 3592 return (error); 3593 } 3594 3595 static int 3596 dlclose_locked(void *handle, RtldLockState *lockstate) 3597 { 3598 Obj_Entry *root; 3599 3600 root = dlcheck(handle); 3601 if (root == NULL) 3602 return (-1); 3603 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3604 root->path); 3605 3606 /* Unreference the object and its dependencies. */ 3607 root->dl_refcount--; 3608 3609 if (root->refcount == 1) { 3610 /* 3611 * The object will be no longer referenced, so we must unload it. 3612 * First, call the fini functions. 3613 */ 3614 objlist_call_fini(&list_fini, root, lockstate); 3615 3616 unref_dag(root); 3617 3618 /* Finish cleaning up the newly-unreferenced objects. */ 3619 GDB_STATE(RT_DELETE,&root->linkmap); 3620 unload_object(root, lockstate); 3621 GDB_STATE(RT_CONSISTENT,NULL); 3622 } else 3623 unref_dag(root); 3624 3625 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3626 return (0); 3627 } 3628 3629 char * 3630 dlerror(void) 3631 { 3632 if (*(lockinfo.dlerror_seen()) != 0) 3633 return (NULL); 3634 *lockinfo.dlerror_seen() = 1; 3635 return (lockinfo.dlerror_loc()); 3636 } 3637 3638 /* 3639 * This function is deprecated and has no effect. 3640 */ 3641 void 3642 dllockinit(void *context, 3643 void *(*_lock_create)(void *context) __unused, 3644 void (*_rlock_acquire)(void *lock) __unused, 3645 void (*_wlock_acquire)(void *lock) __unused, 3646 void (*_lock_release)(void *lock) __unused, 3647 void (*_lock_destroy)(void *lock) __unused, 3648 void (*context_destroy)(void *context)) 3649 { 3650 static void *cur_context; 3651 static void (*cur_context_destroy)(void *); 3652 3653 /* Just destroy the context from the previous call, if necessary. */ 3654 if (cur_context_destroy != NULL) 3655 cur_context_destroy(cur_context); 3656 cur_context = context; 3657 cur_context_destroy = context_destroy; 3658 } 3659 3660 void * 3661 dlopen(const char *name, int mode) 3662 { 3663 3664 return (rtld_dlopen(name, -1, mode)); 3665 } 3666 3667 void * 3668 fdlopen(int fd, int mode) 3669 { 3670 3671 return (rtld_dlopen(NULL, fd, mode)); 3672 } 3673 3674 static void * 3675 rtld_dlopen(const char *name, int fd, int mode) 3676 { 3677 RtldLockState lockstate; 3678 int lo_flags; 3679 3680 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3681 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3682 if (ld_tracing != NULL) { 3683 rlock_acquire(rtld_bind_lock, &lockstate); 3684 if (sigsetjmp(lockstate.env, 0) != 0) 3685 lock_upgrade(rtld_bind_lock, &lockstate); 3686 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3687 lock_release(rtld_bind_lock, &lockstate); 3688 } 3689 lo_flags = RTLD_LO_DLOPEN; 3690 if (mode & RTLD_NODELETE) 3691 lo_flags |= RTLD_LO_NODELETE; 3692 if (mode & RTLD_NOLOAD) 3693 lo_flags |= RTLD_LO_NOLOAD; 3694 if (mode & RTLD_DEEPBIND) 3695 lo_flags |= RTLD_LO_DEEPBIND; 3696 if (ld_tracing != NULL) 3697 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3698 3699 return (dlopen_object(name, fd, obj_main, lo_flags, 3700 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3701 } 3702 3703 static void 3704 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3705 { 3706 3707 obj->dl_refcount--; 3708 unref_dag(obj); 3709 if (obj->refcount == 0) 3710 unload_object(obj, lockstate); 3711 } 3712 3713 static Obj_Entry * 3714 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3715 int mode, RtldLockState *lockstate) 3716 { 3717 Obj_Entry *old_obj_tail; 3718 Obj_Entry *obj; 3719 Objlist initlist; 3720 RtldLockState mlockstate; 3721 int result; 3722 3723 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3724 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3725 refobj->path, lo_flags, mode); 3726 objlist_init(&initlist); 3727 3728 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3729 wlock_acquire(rtld_bind_lock, &mlockstate); 3730 lockstate = &mlockstate; 3731 } 3732 GDB_STATE(RT_ADD,NULL); 3733 3734 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3735 obj = NULL; 3736 if (name == NULL && fd == -1) { 3737 obj = obj_main; 3738 obj->refcount++; 3739 } else { 3740 obj = load_object(name, fd, refobj, lo_flags); 3741 } 3742 3743 if (obj) { 3744 obj->dl_refcount++; 3745 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3746 objlist_push_tail(&list_global, obj); 3747 if (globallist_next(old_obj_tail) != NULL) { 3748 /* We loaded something new. */ 3749 assert(globallist_next(old_obj_tail) == obj); 3750 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3751 obj->symbolic = true; 3752 result = 0; 3753 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3754 obj->static_tls && !allocate_tls_offset(obj)) { 3755 _rtld_error("%s: No space available " 3756 "for static Thread Local Storage", obj->path); 3757 result = -1; 3758 } 3759 if (result != -1) 3760 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3761 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3762 init_dag(obj); 3763 ref_dag(obj); 3764 if (result != -1) 3765 result = rtld_verify_versions(&obj->dagmembers); 3766 if (result != -1 && ld_tracing) 3767 goto trace; 3768 if (result == -1 || relocate_object_dag(obj, 3769 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3770 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3771 lockstate) == -1) { 3772 dlopen_cleanup(obj, lockstate); 3773 obj = NULL; 3774 } else if (lo_flags & RTLD_LO_EARLY) { 3775 /* 3776 * Do not call the init functions for early loaded 3777 * filtees. The image is still not initialized enough 3778 * for them to work. 3779 * 3780 * Our object is found by the global object list and 3781 * will be ordered among all init calls done right 3782 * before transferring control to main. 3783 */ 3784 } else { 3785 /* Make list of init functions to call. */ 3786 initlist_add_objects(obj, obj, &initlist); 3787 } 3788 /* 3789 * Process all no_delete or global objects here, given 3790 * them own DAGs to prevent their dependencies from being 3791 * unloaded. This has to be done after we have loaded all 3792 * of the dependencies, so that we do not miss any. 3793 */ 3794 if (obj != NULL) 3795 process_z(obj); 3796 } else { 3797 /* 3798 * Bump the reference counts for objects on this DAG. If 3799 * this is the first dlopen() call for the object that was 3800 * already loaded as a dependency, initialize the dag 3801 * starting at it. 3802 */ 3803 init_dag(obj); 3804 ref_dag(obj); 3805 3806 if ((lo_flags & RTLD_LO_TRACE) != 0) 3807 goto trace; 3808 } 3809 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3810 obj->z_nodelete) && !obj->ref_nodel) { 3811 dbg("obj %s nodelete", obj->path); 3812 ref_dag(obj); 3813 obj->z_nodelete = obj->ref_nodel = true; 3814 } 3815 } 3816 3817 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3818 name); 3819 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3820 3821 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3822 map_stacks_exec(lockstate); 3823 if (obj != NULL) 3824 distribute_static_tls(&initlist, lockstate); 3825 } 3826 3827 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3828 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3829 lockstate) == -1) { 3830 objlist_clear(&initlist); 3831 dlopen_cleanup(obj, lockstate); 3832 if (lockstate == &mlockstate) 3833 lock_release(rtld_bind_lock, lockstate); 3834 return (NULL); 3835 } 3836 3837 if (!(lo_flags & RTLD_LO_EARLY)) { 3838 /* Call the init functions. */ 3839 objlist_call_init(&initlist, lockstate); 3840 } 3841 objlist_clear(&initlist); 3842 if (lockstate == &mlockstate) 3843 lock_release(rtld_bind_lock, lockstate); 3844 return (obj); 3845 trace: 3846 trace_loaded_objects(obj, false); 3847 if (lockstate == &mlockstate) 3848 lock_release(rtld_bind_lock, lockstate); 3849 exit(0); 3850 } 3851 3852 static void * 3853 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3854 int flags) 3855 { 3856 DoneList donelist; 3857 const Obj_Entry *obj, *defobj; 3858 const Elf_Sym *def; 3859 SymLook req; 3860 RtldLockState lockstate; 3861 tls_index ti; 3862 void *sym; 3863 int res; 3864 3865 def = NULL; 3866 defobj = NULL; 3867 symlook_init(&req, name); 3868 req.ventry = ve; 3869 req.flags = flags | SYMLOOK_IN_PLT; 3870 req.lockstate = &lockstate; 3871 3872 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3873 rlock_acquire(rtld_bind_lock, &lockstate); 3874 if (sigsetjmp(lockstate.env, 0) != 0) 3875 lock_upgrade(rtld_bind_lock, &lockstate); 3876 if (handle == NULL || handle == RTLD_NEXT || 3877 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3878 3879 if ((obj = obj_from_addr(retaddr)) == NULL) { 3880 _rtld_error("Cannot determine caller's shared object"); 3881 lock_release(rtld_bind_lock, &lockstate); 3882 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3883 return (NULL); 3884 } 3885 if (handle == NULL) { /* Just the caller's shared object. */ 3886 res = symlook_obj(&req, obj); 3887 if (res == 0) { 3888 def = req.sym_out; 3889 defobj = req.defobj_out; 3890 } 3891 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3892 handle == RTLD_SELF) { /* ... caller included */ 3893 if (handle == RTLD_NEXT) 3894 obj = globallist_next(obj); 3895 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3896 if (obj->marker) 3897 continue; 3898 res = symlook_obj(&req, obj); 3899 if (res == 0) { 3900 if (def == NULL || (ld_dynamic_weak && 3901 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3902 def = req.sym_out; 3903 defobj = req.defobj_out; 3904 if (!ld_dynamic_weak || 3905 ELF_ST_BIND(def->st_info) != STB_WEAK) 3906 break; 3907 } 3908 } 3909 } 3910 /* 3911 * Search the dynamic linker itself, and possibly resolve the 3912 * symbol from there. This is how the application links to 3913 * dynamic linker services such as dlopen. 3914 * Note that we ignore ld_dynamic_weak == false case, 3915 * always overriding weak symbols by rtld definitions. 3916 */ 3917 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3918 res = symlook_obj(&req, &obj_rtld); 3919 if (res == 0) { 3920 def = req.sym_out; 3921 defobj = req.defobj_out; 3922 } 3923 } 3924 } else { 3925 assert(handle == RTLD_DEFAULT); 3926 res = symlook_default(&req, obj); 3927 if (res == 0) { 3928 defobj = req.defobj_out; 3929 def = req.sym_out; 3930 } 3931 } 3932 } else { 3933 if ((obj = dlcheck(handle)) == NULL) { 3934 lock_release(rtld_bind_lock, &lockstate); 3935 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3936 return (NULL); 3937 } 3938 3939 donelist_init(&donelist); 3940 if (obj->mainprog) { 3941 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3942 res = symlook_global(&req, &donelist); 3943 if (res == 0) { 3944 def = req.sym_out; 3945 defobj = req.defobj_out; 3946 } 3947 /* 3948 * Search the dynamic linker itself, and possibly resolve the 3949 * symbol from there. This is how the application links to 3950 * dynamic linker services such as dlopen. 3951 */ 3952 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3953 res = symlook_obj(&req, &obj_rtld); 3954 if (res == 0) { 3955 def = req.sym_out; 3956 defobj = req.defobj_out; 3957 } 3958 } 3959 } 3960 else { 3961 /* Search the whole DAG rooted at the given object. */ 3962 res = symlook_list(&req, &obj->dagmembers, &donelist); 3963 if (res == 0) { 3964 def = req.sym_out; 3965 defobj = req.defobj_out; 3966 } 3967 } 3968 } 3969 3970 if (def != NULL) { 3971 lock_release(rtld_bind_lock, &lockstate); 3972 3973 /* 3974 * The value required by the caller is derived from the value 3975 * of the symbol. this is simply the relocated value of the 3976 * symbol. 3977 */ 3978 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3979 sym = make_function_pointer(def, defobj); 3980 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3981 sym = rtld_resolve_ifunc(defobj, def); 3982 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3983 ti.ti_module = defobj->tlsindex; 3984 ti.ti_offset = def->st_value; 3985 sym = __tls_get_addr(&ti); 3986 } else 3987 sym = defobj->relocbase + def->st_value; 3988 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3989 return (sym); 3990 } 3991 3992 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3993 ve != NULL ? ve->name : ""); 3994 lock_release(rtld_bind_lock, &lockstate); 3995 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3996 return (NULL); 3997 } 3998 3999 void * 4000 dlsym(void *handle, const char *name) 4001 { 4002 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4003 SYMLOOK_DLSYM)); 4004 } 4005 4006 dlfunc_t 4007 dlfunc(void *handle, const char *name) 4008 { 4009 union { 4010 void *d; 4011 dlfunc_t f; 4012 } rv; 4013 4014 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4015 SYMLOOK_DLSYM); 4016 return (rv.f); 4017 } 4018 4019 void * 4020 dlvsym(void *handle, const char *name, const char *version) 4021 { 4022 Ver_Entry ventry; 4023 4024 ventry.name = version; 4025 ventry.file = NULL; 4026 ventry.hash = elf_hash(version); 4027 ventry.flags= 0; 4028 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4029 SYMLOOK_DLSYM)); 4030 } 4031 4032 int 4033 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4034 { 4035 const Obj_Entry *obj; 4036 RtldLockState lockstate; 4037 4038 rlock_acquire(rtld_bind_lock, &lockstate); 4039 obj = obj_from_addr(addr); 4040 if (obj == NULL) { 4041 _rtld_error("No shared object contains address"); 4042 lock_release(rtld_bind_lock, &lockstate); 4043 return (0); 4044 } 4045 rtld_fill_dl_phdr_info(obj, phdr_info); 4046 lock_release(rtld_bind_lock, &lockstate); 4047 return (1); 4048 } 4049 4050 int 4051 dladdr(const void *addr, Dl_info *info) 4052 { 4053 const Obj_Entry *obj; 4054 const Elf_Sym *def; 4055 void *symbol_addr; 4056 unsigned long symoffset; 4057 RtldLockState lockstate; 4058 4059 rlock_acquire(rtld_bind_lock, &lockstate); 4060 obj = obj_from_addr(addr); 4061 if (obj == NULL) { 4062 _rtld_error("No shared object contains address"); 4063 lock_release(rtld_bind_lock, &lockstate); 4064 return (0); 4065 } 4066 info->dli_fname = obj->path; 4067 info->dli_fbase = obj->mapbase; 4068 info->dli_saddr = (void *)0; 4069 info->dli_sname = NULL; 4070 4071 /* 4072 * Walk the symbol list looking for the symbol whose address is 4073 * closest to the address sent in. 4074 */ 4075 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4076 def = obj->symtab + symoffset; 4077 4078 /* 4079 * For skip the symbol if st_shndx is either SHN_UNDEF or 4080 * SHN_COMMON. 4081 */ 4082 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4083 continue; 4084 4085 /* 4086 * If the symbol is greater than the specified address, or if it 4087 * is further away from addr than the current nearest symbol, 4088 * then reject it. 4089 */ 4090 symbol_addr = obj->relocbase + def->st_value; 4091 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4092 continue; 4093 4094 /* Update our idea of the nearest symbol. */ 4095 info->dli_sname = obj->strtab + def->st_name; 4096 info->dli_saddr = symbol_addr; 4097 4098 /* Exact match? */ 4099 if (info->dli_saddr == addr) 4100 break; 4101 } 4102 lock_release(rtld_bind_lock, &lockstate); 4103 return (1); 4104 } 4105 4106 int 4107 dlinfo(void *handle, int request, void *p) 4108 { 4109 const Obj_Entry *obj; 4110 RtldLockState lockstate; 4111 int error; 4112 4113 rlock_acquire(rtld_bind_lock, &lockstate); 4114 4115 if (handle == NULL || handle == RTLD_SELF) { 4116 void *retaddr; 4117 4118 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4119 if ((obj = obj_from_addr(retaddr)) == NULL) 4120 _rtld_error("Cannot determine caller's shared object"); 4121 } else 4122 obj = dlcheck(handle); 4123 4124 if (obj == NULL) { 4125 lock_release(rtld_bind_lock, &lockstate); 4126 return (-1); 4127 } 4128 4129 error = 0; 4130 switch (request) { 4131 case RTLD_DI_LINKMAP: 4132 *((struct link_map const **)p) = &obj->linkmap; 4133 break; 4134 case RTLD_DI_ORIGIN: 4135 error = rtld_dirname(obj->path, p); 4136 break; 4137 4138 case RTLD_DI_SERINFOSIZE: 4139 case RTLD_DI_SERINFO: 4140 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4141 break; 4142 4143 default: 4144 _rtld_error("Invalid request %d passed to dlinfo()", request); 4145 error = -1; 4146 } 4147 4148 lock_release(rtld_bind_lock, &lockstate); 4149 4150 return (error); 4151 } 4152 4153 static void 4154 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4155 { 4156 uintptr_t **dtvp; 4157 4158 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4159 phdr_info->dlpi_name = obj->path; 4160 phdr_info->dlpi_phdr = obj->phdr; 4161 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4162 phdr_info->dlpi_tls_modid = obj->tlsindex; 4163 dtvp = &_tcb_get()->tcb_dtv; 4164 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4165 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4166 phdr_info->dlpi_adds = obj_loads; 4167 phdr_info->dlpi_subs = obj_loads - obj_count; 4168 } 4169 4170 int 4171 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4172 { 4173 struct dl_phdr_info phdr_info; 4174 Obj_Entry *obj, marker; 4175 RtldLockState bind_lockstate, phdr_lockstate; 4176 int error; 4177 4178 init_marker(&marker); 4179 error = 0; 4180 4181 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4182 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4183 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4184 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4185 rtld_fill_dl_phdr_info(obj, &phdr_info); 4186 hold_object(obj); 4187 lock_release(rtld_bind_lock, &bind_lockstate); 4188 4189 error = callback(&phdr_info, sizeof phdr_info, param); 4190 4191 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4192 unhold_object(obj); 4193 obj = globallist_next(&marker); 4194 TAILQ_REMOVE(&obj_list, &marker, next); 4195 if (error != 0) { 4196 lock_release(rtld_bind_lock, &bind_lockstate); 4197 lock_release(rtld_phdr_lock, &phdr_lockstate); 4198 return (error); 4199 } 4200 } 4201 4202 if (error == 0) { 4203 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4204 lock_release(rtld_bind_lock, &bind_lockstate); 4205 error = callback(&phdr_info, sizeof(phdr_info), param); 4206 } 4207 lock_release(rtld_phdr_lock, &phdr_lockstate); 4208 return (error); 4209 } 4210 4211 static void * 4212 fill_search_info(const char *dir, size_t dirlen, void *param) 4213 { 4214 struct fill_search_info_args *arg; 4215 4216 arg = param; 4217 4218 if (arg->request == RTLD_DI_SERINFOSIZE) { 4219 arg->serinfo->dls_cnt ++; 4220 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4221 } else { 4222 struct dl_serpath *s_entry; 4223 4224 s_entry = arg->serpath; 4225 s_entry->dls_name = arg->strspace; 4226 s_entry->dls_flags = arg->flags; 4227 4228 strncpy(arg->strspace, dir, dirlen); 4229 arg->strspace[dirlen] = '\0'; 4230 4231 arg->strspace += dirlen + 1; 4232 arg->serpath++; 4233 } 4234 4235 return (NULL); 4236 } 4237 4238 static int 4239 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4240 { 4241 struct dl_serinfo _info; 4242 struct fill_search_info_args args; 4243 4244 args.request = RTLD_DI_SERINFOSIZE; 4245 args.serinfo = &_info; 4246 4247 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4248 _info.dls_cnt = 0; 4249 4250 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4251 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4252 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4253 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4254 if (!obj->z_nodeflib) 4255 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4256 4257 4258 if (request == RTLD_DI_SERINFOSIZE) { 4259 info->dls_size = _info.dls_size; 4260 info->dls_cnt = _info.dls_cnt; 4261 return (0); 4262 } 4263 4264 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4265 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4266 return (-1); 4267 } 4268 4269 args.request = RTLD_DI_SERINFO; 4270 args.serinfo = info; 4271 args.serpath = &info->dls_serpath[0]; 4272 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4273 4274 args.flags = LA_SER_RUNPATH; 4275 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4276 return (-1); 4277 4278 args.flags = LA_SER_LIBPATH; 4279 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4280 return (-1); 4281 4282 args.flags = LA_SER_RUNPATH; 4283 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4284 return (-1); 4285 4286 args.flags = LA_SER_CONFIG; 4287 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4288 != NULL) 4289 return (-1); 4290 4291 args.flags = LA_SER_DEFAULT; 4292 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4293 fill_search_info, NULL, &args) != NULL) 4294 return (-1); 4295 return (0); 4296 } 4297 4298 static int 4299 rtld_dirname(const char *path, char *bname) 4300 { 4301 const char *endp; 4302 4303 /* Empty or NULL string gets treated as "." */ 4304 if (path == NULL || *path == '\0') { 4305 bname[0] = '.'; 4306 bname[1] = '\0'; 4307 return (0); 4308 } 4309 4310 /* Strip trailing slashes */ 4311 endp = path + strlen(path) - 1; 4312 while (endp > path && *endp == '/') 4313 endp--; 4314 4315 /* Find the start of the dir */ 4316 while (endp > path && *endp != '/') 4317 endp--; 4318 4319 /* Either the dir is "/" or there are no slashes */ 4320 if (endp == path) { 4321 bname[0] = *endp == '/' ? '/' : '.'; 4322 bname[1] = '\0'; 4323 return (0); 4324 } else { 4325 do { 4326 endp--; 4327 } while (endp > path && *endp == '/'); 4328 } 4329 4330 if (endp - path + 2 > PATH_MAX) 4331 { 4332 _rtld_error("Filename is too long: %s", path); 4333 return(-1); 4334 } 4335 4336 strncpy(bname, path, endp - path + 1); 4337 bname[endp - path + 1] = '\0'; 4338 return (0); 4339 } 4340 4341 static int 4342 rtld_dirname_abs(const char *path, char *base) 4343 { 4344 char *last; 4345 4346 if (realpath(path, base) == NULL) { 4347 _rtld_error("realpath \"%s\" failed (%s)", path, 4348 rtld_strerror(errno)); 4349 return (-1); 4350 } 4351 dbg("%s -> %s", path, base); 4352 last = strrchr(base, '/'); 4353 if (last == NULL) { 4354 _rtld_error("non-abs result from realpath \"%s\"", path); 4355 return (-1); 4356 } 4357 if (last != base) 4358 *last = '\0'; 4359 return (0); 4360 } 4361 4362 static void 4363 linkmap_add(Obj_Entry *obj) 4364 { 4365 struct link_map *l, *prev; 4366 4367 l = &obj->linkmap; 4368 l->l_name = obj->path; 4369 l->l_base = obj->mapbase; 4370 l->l_ld = obj->dynamic; 4371 l->l_addr = obj->relocbase; 4372 4373 if (r_debug.r_map == NULL) { 4374 r_debug.r_map = l; 4375 return; 4376 } 4377 4378 /* 4379 * Scan to the end of the list, but not past the entry for the 4380 * dynamic linker, which we want to keep at the very end. 4381 */ 4382 for (prev = r_debug.r_map; 4383 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4384 prev = prev->l_next) 4385 ; 4386 4387 /* Link in the new entry. */ 4388 l->l_prev = prev; 4389 l->l_next = prev->l_next; 4390 if (l->l_next != NULL) 4391 l->l_next->l_prev = l; 4392 prev->l_next = l; 4393 } 4394 4395 static void 4396 linkmap_delete(Obj_Entry *obj) 4397 { 4398 struct link_map *l; 4399 4400 l = &obj->linkmap; 4401 if (l->l_prev == NULL) { 4402 if ((r_debug.r_map = l->l_next) != NULL) 4403 l->l_next->l_prev = NULL; 4404 return; 4405 } 4406 4407 if ((l->l_prev->l_next = l->l_next) != NULL) 4408 l->l_next->l_prev = l->l_prev; 4409 } 4410 4411 /* 4412 * Function for the debugger to set a breakpoint on to gain control. 4413 * 4414 * The two parameters allow the debugger to easily find and determine 4415 * what the runtime loader is doing and to whom it is doing it. 4416 * 4417 * When the loadhook trap is hit (r_debug_state, set at program 4418 * initialization), the arguments can be found on the stack: 4419 * 4420 * +8 struct link_map *m 4421 * +4 struct r_debug *rd 4422 * +0 RetAddr 4423 */ 4424 void 4425 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4426 { 4427 /* 4428 * The following is a hack to force the compiler to emit calls to 4429 * this function, even when optimizing. If the function is empty, 4430 * the compiler is not obliged to emit any code for calls to it, 4431 * even when marked __noinline. However, gdb depends on those 4432 * calls being made. 4433 */ 4434 __compiler_membar(); 4435 } 4436 4437 /* 4438 * A function called after init routines have completed. This can be used to 4439 * break before a program's entry routine is called, and can be used when 4440 * main is not available in the symbol table. 4441 */ 4442 void 4443 _r_debug_postinit(struct link_map *m __unused) 4444 { 4445 4446 /* See r_debug_state(). */ 4447 __compiler_membar(); 4448 } 4449 4450 static void 4451 release_object(Obj_Entry *obj) 4452 { 4453 4454 if (obj->holdcount > 0) { 4455 obj->unholdfree = true; 4456 return; 4457 } 4458 munmap(obj->mapbase, obj->mapsize); 4459 linkmap_delete(obj); 4460 obj_free(obj); 4461 } 4462 4463 /* 4464 * Get address of the pointer variable in the main program. 4465 * Prefer non-weak symbol over the weak one. 4466 */ 4467 static const void ** 4468 get_program_var_addr(const char *name, RtldLockState *lockstate) 4469 { 4470 SymLook req; 4471 DoneList donelist; 4472 4473 symlook_init(&req, name); 4474 req.lockstate = lockstate; 4475 donelist_init(&donelist); 4476 if (symlook_global(&req, &donelist) != 0) 4477 return (NULL); 4478 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4479 return ((const void **)make_function_pointer(req.sym_out, 4480 req.defobj_out)); 4481 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4482 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4483 else 4484 return ((const void **)(req.defobj_out->relocbase + 4485 req.sym_out->st_value)); 4486 } 4487 4488 /* 4489 * Set a pointer variable in the main program to the given value. This 4490 * is used to set key variables such as "environ" before any of the 4491 * init functions are called. 4492 */ 4493 static void 4494 set_program_var(const char *name, const void *value) 4495 { 4496 const void **addr; 4497 4498 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4499 dbg("\"%s\": *%p <-- %p", name, addr, value); 4500 *addr = value; 4501 } 4502 } 4503 4504 /* 4505 * Search the global objects, including dependencies and main object, 4506 * for the given symbol. 4507 */ 4508 static int 4509 symlook_global(SymLook *req, DoneList *donelist) 4510 { 4511 SymLook req1; 4512 const Objlist_Entry *elm; 4513 int res; 4514 4515 symlook_init_from_req(&req1, req); 4516 4517 /* Search all objects loaded at program start up. */ 4518 if (req->defobj_out == NULL || (ld_dynamic_weak && 4519 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4520 res = symlook_list(&req1, &list_main, donelist); 4521 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4522 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4523 req->sym_out = req1.sym_out; 4524 req->defobj_out = req1.defobj_out; 4525 assert(req->defobj_out != NULL); 4526 } 4527 } 4528 4529 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4530 STAILQ_FOREACH(elm, &list_global, link) { 4531 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4532 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4533 break; 4534 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4535 if (res == 0 && (req->defobj_out == NULL || 4536 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4537 req->sym_out = req1.sym_out; 4538 req->defobj_out = req1.defobj_out; 4539 assert(req->defobj_out != NULL); 4540 } 4541 } 4542 4543 return (req->sym_out != NULL ? 0 : ESRCH); 4544 } 4545 4546 /* 4547 * Given a symbol name in a referencing object, find the corresponding 4548 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4549 * no definition was found. Returns a pointer to the Obj_Entry of the 4550 * defining object via the reference parameter DEFOBJ_OUT. 4551 */ 4552 static int 4553 symlook_default(SymLook *req, const Obj_Entry *refobj) 4554 { 4555 DoneList donelist; 4556 const Objlist_Entry *elm; 4557 SymLook req1; 4558 int res; 4559 4560 donelist_init(&donelist); 4561 symlook_init_from_req(&req1, req); 4562 4563 /* 4564 * Look first in the referencing object if linked symbolically, 4565 * and similarly handle protected symbols. 4566 */ 4567 res = symlook_obj(&req1, refobj); 4568 if (res == 0 && (refobj->symbolic || 4569 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4570 req->sym_out = req1.sym_out; 4571 req->defobj_out = req1.defobj_out; 4572 assert(req->defobj_out != NULL); 4573 } 4574 if (refobj->symbolic || req->defobj_out != NULL) 4575 donelist_check(&donelist, refobj); 4576 4577 symlook_global(req, &donelist); 4578 4579 /* Search all dlopened DAGs containing the referencing object. */ 4580 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4581 if (req->sym_out != NULL && (!ld_dynamic_weak || 4582 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4583 break; 4584 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4585 if (res == 0 && (req->sym_out == NULL || 4586 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4587 req->sym_out = req1.sym_out; 4588 req->defobj_out = req1.defobj_out; 4589 assert(req->defobj_out != NULL); 4590 } 4591 } 4592 4593 /* 4594 * Search the dynamic linker itself, and possibly resolve the 4595 * symbol from there. This is how the application links to 4596 * dynamic linker services such as dlopen. 4597 */ 4598 if (req->sym_out == NULL || 4599 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4600 res = symlook_obj(&req1, &obj_rtld); 4601 if (res == 0) { 4602 req->sym_out = req1.sym_out; 4603 req->defobj_out = req1.defobj_out; 4604 assert(req->defobj_out != NULL); 4605 } 4606 } 4607 4608 return (req->sym_out != NULL ? 0 : ESRCH); 4609 } 4610 4611 static int 4612 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4613 { 4614 const Elf_Sym *def; 4615 const Obj_Entry *defobj; 4616 const Objlist_Entry *elm; 4617 SymLook req1; 4618 int res; 4619 4620 def = NULL; 4621 defobj = NULL; 4622 STAILQ_FOREACH(elm, objlist, link) { 4623 if (donelist_check(dlp, elm->obj)) 4624 continue; 4625 symlook_init_from_req(&req1, req); 4626 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4627 if (def == NULL || (ld_dynamic_weak && 4628 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4629 def = req1.sym_out; 4630 defobj = req1.defobj_out; 4631 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4632 break; 4633 } 4634 } 4635 } 4636 if (def != NULL) { 4637 req->sym_out = def; 4638 req->defobj_out = defobj; 4639 return (0); 4640 } 4641 return (ESRCH); 4642 } 4643 4644 /* 4645 * Search the chain of DAGS cointed to by the given Needed_Entry 4646 * for a symbol of the given name. Each DAG is scanned completely 4647 * before advancing to the next one. Returns a pointer to the symbol, 4648 * or NULL if no definition was found. 4649 */ 4650 static int 4651 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4652 { 4653 const Elf_Sym *def; 4654 const Needed_Entry *n; 4655 const Obj_Entry *defobj; 4656 SymLook req1; 4657 int res; 4658 4659 def = NULL; 4660 defobj = NULL; 4661 symlook_init_from_req(&req1, req); 4662 for (n = needed; n != NULL; n = n->next) { 4663 if (n->obj == NULL || 4664 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4665 continue; 4666 if (def == NULL || (ld_dynamic_weak && 4667 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4668 def = req1.sym_out; 4669 defobj = req1.defobj_out; 4670 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4671 break; 4672 } 4673 } 4674 if (def != NULL) { 4675 req->sym_out = def; 4676 req->defobj_out = defobj; 4677 return (0); 4678 } 4679 return (ESRCH); 4680 } 4681 4682 /* 4683 * Search the symbol table of a single shared object for a symbol of 4684 * the given name and version, if requested. Returns a pointer to the 4685 * symbol, or NULL if no definition was found. If the object is 4686 * filter, return filtered symbol from filtee. 4687 * 4688 * The symbol's hash value is passed in for efficiency reasons; that 4689 * eliminates many recomputations of the hash value. 4690 */ 4691 int 4692 symlook_obj(SymLook *req, const Obj_Entry *obj) 4693 { 4694 DoneList donelist; 4695 SymLook req1; 4696 int flags, res, mres; 4697 4698 /* 4699 * If there is at least one valid hash at this point, we prefer to 4700 * use the faster GNU version if available. 4701 */ 4702 if (obj->valid_hash_gnu) 4703 mres = symlook_obj1_gnu(req, obj); 4704 else if (obj->valid_hash_sysv) 4705 mres = symlook_obj1_sysv(req, obj); 4706 else 4707 return (EINVAL); 4708 4709 if (mres == 0) { 4710 if (obj->needed_filtees != NULL) { 4711 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4712 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4713 donelist_init(&donelist); 4714 symlook_init_from_req(&req1, req); 4715 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4716 if (res == 0) { 4717 req->sym_out = req1.sym_out; 4718 req->defobj_out = req1.defobj_out; 4719 } 4720 return (res); 4721 } 4722 if (obj->needed_aux_filtees != NULL) { 4723 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4724 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4725 donelist_init(&donelist); 4726 symlook_init_from_req(&req1, req); 4727 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4728 if (res == 0) { 4729 req->sym_out = req1.sym_out; 4730 req->defobj_out = req1.defobj_out; 4731 return (res); 4732 } 4733 } 4734 } 4735 return (mres); 4736 } 4737 4738 /* Symbol match routine common to both hash functions */ 4739 static bool 4740 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4741 const unsigned long symnum) 4742 { 4743 Elf_Versym verndx; 4744 const Elf_Sym *symp; 4745 const char *strp; 4746 4747 symp = obj->symtab + symnum; 4748 strp = obj->strtab + symp->st_name; 4749 4750 switch (ELF_ST_TYPE(symp->st_info)) { 4751 case STT_FUNC: 4752 case STT_NOTYPE: 4753 case STT_OBJECT: 4754 case STT_COMMON: 4755 case STT_GNU_IFUNC: 4756 if (symp->st_value == 0) 4757 return (false); 4758 /* fallthrough */ 4759 case STT_TLS: 4760 if (symp->st_shndx != SHN_UNDEF) 4761 break; 4762 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4763 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4764 break; 4765 /* fallthrough */ 4766 default: 4767 return (false); 4768 } 4769 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4770 return (false); 4771 4772 if (req->ventry == NULL) { 4773 if (obj->versyms != NULL) { 4774 verndx = VER_NDX(obj->versyms[symnum]); 4775 if (verndx > obj->vernum) { 4776 _rtld_error( 4777 "%s: symbol %s references wrong version %d", 4778 obj->path, obj->strtab + symnum, verndx); 4779 return (false); 4780 } 4781 /* 4782 * If we are not called from dlsym (i.e. this 4783 * is a normal relocation from unversioned 4784 * binary), accept the symbol immediately if 4785 * it happens to have first version after this 4786 * shared object became versioned. Otherwise, 4787 * if symbol is versioned and not hidden, 4788 * remember it. If it is the only symbol with 4789 * this name exported by the shared object, it 4790 * will be returned as a match by the calling 4791 * function. If symbol is global (verndx < 2) 4792 * accept it unconditionally. 4793 */ 4794 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4795 verndx == VER_NDX_GIVEN) { 4796 result->sym_out = symp; 4797 return (true); 4798 } 4799 else if (verndx >= VER_NDX_GIVEN) { 4800 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4801 == 0) { 4802 if (result->vsymp == NULL) 4803 result->vsymp = symp; 4804 result->vcount++; 4805 } 4806 return (false); 4807 } 4808 } 4809 result->sym_out = symp; 4810 return (true); 4811 } 4812 if (obj->versyms == NULL) { 4813 if (object_match_name(obj, req->ventry->name)) { 4814 _rtld_error("%s: object %s should provide version %s " 4815 "for symbol %s", obj_rtld.path, obj->path, 4816 req->ventry->name, obj->strtab + symnum); 4817 return (false); 4818 } 4819 } else { 4820 verndx = VER_NDX(obj->versyms[symnum]); 4821 if (verndx > obj->vernum) { 4822 _rtld_error("%s: symbol %s references wrong version %d", 4823 obj->path, obj->strtab + symnum, verndx); 4824 return (false); 4825 } 4826 if (obj->vertab[verndx].hash != req->ventry->hash || 4827 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4828 /* 4829 * Version does not match. Look if this is a 4830 * global symbol and if it is not hidden. If 4831 * global symbol (verndx < 2) is available, 4832 * use it. Do not return symbol if we are 4833 * called by dlvsym, because dlvsym looks for 4834 * a specific version and default one is not 4835 * what dlvsym wants. 4836 */ 4837 if ((req->flags & SYMLOOK_DLSYM) || 4838 (verndx >= VER_NDX_GIVEN) || 4839 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4840 return (false); 4841 } 4842 } 4843 result->sym_out = symp; 4844 return (true); 4845 } 4846 4847 /* 4848 * Search for symbol using SysV hash function. 4849 * obj->buckets is known not to be NULL at this point; the test for this was 4850 * performed with the obj->valid_hash_sysv assignment. 4851 */ 4852 static int 4853 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4854 { 4855 unsigned long symnum; 4856 Sym_Match_Result matchres; 4857 4858 matchres.sym_out = NULL; 4859 matchres.vsymp = NULL; 4860 matchres.vcount = 0; 4861 4862 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4863 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4864 if (symnum >= obj->nchains) 4865 return (ESRCH); /* Bad object */ 4866 4867 if (matched_symbol(req, obj, &matchres, symnum)) { 4868 req->sym_out = matchres.sym_out; 4869 req->defobj_out = obj; 4870 return (0); 4871 } 4872 } 4873 if (matchres.vcount == 1) { 4874 req->sym_out = matchres.vsymp; 4875 req->defobj_out = obj; 4876 return (0); 4877 } 4878 return (ESRCH); 4879 } 4880 4881 /* Search for symbol using GNU hash function */ 4882 static int 4883 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4884 { 4885 Elf_Addr bloom_word; 4886 const Elf32_Word *hashval; 4887 Elf32_Word bucket; 4888 Sym_Match_Result matchres; 4889 unsigned int h1, h2; 4890 unsigned long symnum; 4891 4892 matchres.sym_out = NULL; 4893 matchres.vsymp = NULL; 4894 matchres.vcount = 0; 4895 4896 /* Pick right bitmask word from Bloom filter array */ 4897 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4898 obj->maskwords_bm_gnu]; 4899 4900 /* Calculate modulus word size of gnu hash and its derivative */ 4901 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4902 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4903 4904 /* Filter out the "definitely not in set" queries */ 4905 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4906 return (ESRCH); 4907 4908 /* Locate hash chain and corresponding value element*/ 4909 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4910 if (bucket == 0) 4911 return (ESRCH); 4912 hashval = &obj->chain_zero_gnu[bucket]; 4913 do { 4914 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4915 symnum = hashval - obj->chain_zero_gnu; 4916 if (matched_symbol(req, obj, &matchres, symnum)) { 4917 req->sym_out = matchres.sym_out; 4918 req->defobj_out = obj; 4919 return (0); 4920 } 4921 } 4922 } while ((*hashval++ & 1) == 0); 4923 if (matchres.vcount == 1) { 4924 req->sym_out = matchres.vsymp; 4925 req->defobj_out = obj; 4926 return (0); 4927 } 4928 return (ESRCH); 4929 } 4930 4931 static void 4932 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4933 { 4934 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4935 if (*main_local == NULL) 4936 *main_local = ""; 4937 4938 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4939 if (*fmt1 == NULL) 4940 *fmt1 = "\t%o => %p (%x)\n"; 4941 4942 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4943 if (*fmt2 == NULL) 4944 *fmt2 = "\t%o (%x)\n"; 4945 } 4946 4947 static void 4948 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4949 const char *main_local, const char *fmt1, const char *fmt2) 4950 { 4951 const char *fmt; 4952 int c; 4953 4954 if (fmt1 == NULL) 4955 fmt = fmt2; 4956 else 4957 /* XXX bogus */ 4958 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 4959 4960 while ((c = *fmt++) != '\0') { 4961 switch (c) { 4962 default: 4963 rtld_putchar(c); 4964 continue; 4965 case '\\': 4966 switch (c = *fmt) { 4967 case '\0': 4968 continue; 4969 case 'n': 4970 rtld_putchar('\n'); 4971 break; 4972 case 't': 4973 rtld_putchar('\t'); 4974 break; 4975 } 4976 break; 4977 case '%': 4978 switch (c = *fmt) { 4979 case '\0': 4980 continue; 4981 case '%': 4982 default: 4983 rtld_putchar(c); 4984 break; 4985 case 'A': 4986 rtld_putstr(main_local); 4987 break; 4988 case 'a': 4989 rtld_putstr(obj_main->path); 4990 break; 4991 case 'o': 4992 rtld_putstr(name); 4993 break; 4994 case 'p': 4995 rtld_putstr(path); 4996 break; 4997 case 'x': 4998 rtld_printf("%p", obj != NULL ? 4999 obj->mapbase : NULL); 5000 break; 5001 } 5002 break; 5003 } 5004 ++fmt; 5005 } 5006 } 5007 5008 static void 5009 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5010 { 5011 const char *fmt1, *fmt2, *main_local; 5012 const char *name, *path; 5013 bool first_spurious, list_containers; 5014 5015 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5016 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5017 5018 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5019 Needed_Entry *needed; 5020 5021 if (obj->marker) 5022 continue; 5023 if (list_containers && obj->needed != NULL) 5024 rtld_printf("%s:\n", obj->path); 5025 for (needed = obj->needed; needed; needed = needed->next) { 5026 if (needed->obj != NULL) { 5027 if (needed->obj->traced && !list_containers) 5028 continue; 5029 needed->obj->traced = true; 5030 path = needed->obj->path; 5031 } else 5032 path = "not found"; 5033 5034 name = obj->strtab + needed->name; 5035 trace_print_obj(needed->obj, name, path, main_local, 5036 fmt1, fmt2); 5037 } 5038 } 5039 5040 if (show_preload) { 5041 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5042 fmt2 = "\t%p (%x)\n"; 5043 first_spurious = true; 5044 5045 TAILQ_FOREACH(obj, &obj_list, next) { 5046 if (obj->marker || obj == obj_main || obj->traced) 5047 continue; 5048 5049 if (list_containers && first_spurious) { 5050 rtld_printf("[preloaded]\n"); 5051 first_spurious = false; 5052 } 5053 5054 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5055 name = fname == NULL ? "<unknown>" : fname->name; 5056 trace_print_obj(obj, name, obj->path, main_local, 5057 NULL, fmt2); 5058 } 5059 } 5060 } 5061 5062 /* 5063 * Unload a dlopened object and its dependencies from memory and from 5064 * our data structures. It is assumed that the DAG rooted in the 5065 * object has already been unreferenced, and that the object has a 5066 * reference count of 0. 5067 */ 5068 static void 5069 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5070 { 5071 Obj_Entry marker, *obj, *next; 5072 5073 assert(root->refcount == 0); 5074 5075 /* 5076 * Pass over the DAG removing unreferenced objects from 5077 * appropriate lists. 5078 */ 5079 unlink_object(root); 5080 5081 /* Unmap all objects that are no longer referenced. */ 5082 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5083 next = TAILQ_NEXT(obj, next); 5084 if (obj->marker || obj->refcount != 0) 5085 continue; 5086 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5087 obj->mapsize, 0, obj->path); 5088 dbg("unloading \"%s\"", obj->path); 5089 /* 5090 * Unlink the object now to prevent new references from 5091 * being acquired while the bind lock is dropped in 5092 * recursive dlclose() invocations. 5093 */ 5094 TAILQ_REMOVE(&obj_list, obj, next); 5095 obj_count--; 5096 5097 if (obj->filtees_loaded) { 5098 if (next != NULL) { 5099 init_marker(&marker); 5100 TAILQ_INSERT_BEFORE(next, &marker, next); 5101 unload_filtees(obj, lockstate); 5102 next = TAILQ_NEXT(&marker, next); 5103 TAILQ_REMOVE(&obj_list, &marker, next); 5104 } else 5105 unload_filtees(obj, lockstate); 5106 } 5107 release_object(obj); 5108 } 5109 } 5110 5111 static void 5112 unlink_object(Obj_Entry *root) 5113 { 5114 Objlist_Entry *elm; 5115 5116 if (root->refcount == 0) { 5117 /* Remove the object from the RTLD_GLOBAL list. */ 5118 objlist_remove(&list_global, root); 5119 5120 /* Remove the object from all objects' DAG lists. */ 5121 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5122 objlist_remove(&elm->obj->dldags, root); 5123 if (elm->obj != root) 5124 unlink_object(elm->obj); 5125 } 5126 } 5127 } 5128 5129 static void 5130 ref_dag(Obj_Entry *root) 5131 { 5132 Objlist_Entry *elm; 5133 5134 assert(root->dag_inited); 5135 STAILQ_FOREACH(elm, &root->dagmembers, link) 5136 elm->obj->refcount++; 5137 } 5138 5139 static void 5140 unref_dag(Obj_Entry *root) 5141 { 5142 Objlist_Entry *elm; 5143 5144 assert(root->dag_inited); 5145 STAILQ_FOREACH(elm, &root->dagmembers, link) 5146 elm->obj->refcount--; 5147 } 5148 5149 /* 5150 * Common code for MD __tls_get_addr(). 5151 */ 5152 static void * 5153 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5154 { 5155 Elf_Addr *newdtv, *dtv; 5156 RtldLockState lockstate; 5157 int to_copy; 5158 5159 dtv = *dtvp; 5160 /* Check dtv generation in case new modules have arrived */ 5161 if (dtv[0] != tls_dtv_generation) { 5162 if (!locked) 5163 wlock_acquire(rtld_bind_lock, &lockstate); 5164 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5165 to_copy = dtv[1]; 5166 if (to_copy > tls_max_index) 5167 to_copy = tls_max_index; 5168 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5169 newdtv[0] = tls_dtv_generation; 5170 newdtv[1] = tls_max_index; 5171 free(dtv); 5172 if (!locked) 5173 lock_release(rtld_bind_lock, &lockstate); 5174 dtv = *dtvp = newdtv; 5175 } 5176 5177 /* Dynamically allocate module TLS if necessary */ 5178 if (dtv[index + 1] == 0) { 5179 /* Signal safe, wlock will block out signals. */ 5180 if (!locked) 5181 wlock_acquire(rtld_bind_lock, &lockstate); 5182 if (!dtv[index + 1]) 5183 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5184 if (!locked) 5185 lock_release(rtld_bind_lock, &lockstate); 5186 } 5187 return ((void *)(dtv[index + 1] + offset)); 5188 } 5189 5190 void * 5191 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5192 { 5193 uintptr_t *dtv; 5194 5195 dtv = *dtvp; 5196 /* Check dtv generation in case new modules have arrived */ 5197 if (__predict_true(dtv[0] == tls_dtv_generation && 5198 dtv[index + 1] != 0)) 5199 return ((void *)(dtv[index + 1] + offset)); 5200 return (tls_get_addr_slow(dtvp, index, offset, false)); 5201 } 5202 5203 #ifdef TLS_VARIANT_I 5204 5205 /* 5206 * Return pointer to allocated TLS block 5207 */ 5208 static void * 5209 get_tls_block_ptr(void *tcb, size_t tcbsize) 5210 { 5211 size_t extra_size, post_size, pre_size, tls_block_size; 5212 size_t tls_init_align; 5213 5214 tls_init_align = MAX(obj_main->tlsalign, 1); 5215 5216 /* Compute fragments sizes. */ 5217 extra_size = tcbsize - TLS_TCB_SIZE; 5218 post_size = calculate_tls_post_size(tls_init_align); 5219 tls_block_size = tcbsize + post_size; 5220 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5221 5222 return ((char *)tcb - pre_size - extra_size); 5223 } 5224 5225 /* 5226 * Allocate Static TLS using the Variant I method. 5227 * 5228 * For details on the layout, see lib/libc/gen/tls.c. 5229 * 5230 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5231 * it is based on tls_last_offset, and TLS offsets here are really TCB 5232 * offsets, whereas libc's tls_static_space is just the executable's static 5233 * TLS segment. 5234 */ 5235 void * 5236 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5237 { 5238 Obj_Entry *obj; 5239 char *tls_block; 5240 Elf_Addr *dtv, **tcb; 5241 Elf_Addr addr; 5242 Elf_Addr i; 5243 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5244 size_t tls_init_align, tls_init_offset; 5245 5246 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5247 return (oldtcb); 5248 5249 assert(tcbsize >= TLS_TCB_SIZE); 5250 maxalign = MAX(tcbalign, tls_static_max_align); 5251 tls_init_align = MAX(obj_main->tlsalign, 1); 5252 5253 /* Compute fragmets sizes. */ 5254 extra_size = tcbsize - TLS_TCB_SIZE; 5255 post_size = calculate_tls_post_size(tls_init_align); 5256 tls_block_size = tcbsize + post_size; 5257 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5258 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5259 5260 /* Allocate whole TLS block */ 5261 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5262 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5263 5264 if (oldtcb != NULL) { 5265 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5266 tls_static_space); 5267 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5268 5269 /* Adjust the DTV. */ 5270 dtv = tcb[0]; 5271 for (i = 0; i < dtv[1]; i++) { 5272 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5273 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5274 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5275 } 5276 } 5277 } else { 5278 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5279 tcb[0] = dtv; 5280 dtv[0] = tls_dtv_generation; 5281 dtv[1] = tls_max_index; 5282 5283 for (obj = globallist_curr(objs); obj != NULL; 5284 obj = globallist_next(obj)) { 5285 if (obj->tlsoffset == 0) 5286 continue; 5287 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5288 addr = (Elf_Addr)tcb + obj->tlsoffset; 5289 if (tls_init_offset > 0) 5290 memset((void *)addr, 0, tls_init_offset); 5291 if (obj->tlsinitsize > 0) { 5292 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5293 obj->tlsinitsize); 5294 } 5295 if (obj->tlssize > obj->tlsinitsize) { 5296 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5297 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5298 } 5299 dtv[obj->tlsindex + 1] = addr; 5300 } 5301 } 5302 5303 return (tcb); 5304 } 5305 5306 void 5307 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5308 { 5309 Elf_Addr *dtv; 5310 Elf_Addr tlsstart, tlsend; 5311 size_t post_size; 5312 size_t dtvsize, i, tls_init_align; 5313 5314 assert(tcbsize >= TLS_TCB_SIZE); 5315 tls_init_align = MAX(obj_main->tlsalign, 1); 5316 5317 /* Compute fragments sizes. */ 5318 post_size = calculate_tls_post_size(tls_init_align); 5319 5320 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5321 tlsend = (Elf_Addr)tcb + tls_static_space; 5322 5323 dtv = *(Elf_Addr **)tcb; 5324 dtvsize = dtv[1]; 5325 for (i = 0; i < dtvsize; i++) { 5326 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5327 free((void*)dtv[i+2]); 5328 } 5329 } 5330 free(dtv); 5331 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5332 } 5333 5334 #endif /* TLS_VARIANT_I */ 5335 5336 #ifdef TLS_VARIANT_II 5337 5338 /* 5339 * Allocate Static TLS using the Variant II method. 5340 */ 5341 void * 5342 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5343 { 5344 Obj_Entry *obj; 5345 size_t size, ralign; 5346 char *tls; 5347 Elf_Addr *dtv, *olddtv; 5348 Elf_Addr segbase, oldsegbase, addr; 5349 size_t i; 5350 5351 ralign = tcbalign; 5352 if (tls_static_max_align > ralign) 5353 ralign = tls_static_max_align; 5354 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5355 5356 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5357 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5358 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5359 5360 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5361 ((Elf_Addr *)segbase)[0] = segbase; 5362 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5363 5364 dtv[0] = tls_dtv_generation; 5365 dtv[1] = tls_max_index; 5366 5367 if (oldtls) { 5368 /* 5369 * Copy the static TLS block over whole. 5370 */ 5371 oldsegbase = (Elf_Addr) oldtls; 5372 memcpy((void *)(segbase - tls_static_space), 5373 (const void *)(oldsegbase - tls_static_space), 5374 tls_static_space); 5375 5376 /* 5377 * If any dynamic TLS blocks have been created tls_get_addr(), 5378 * move them over. 5379 */ 5380 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5381 for (i = 0; i < olddtv[1]; i++) { 5382 if (olddtv[i + 2] < oldsegbase - size || 5383 olddtv[i + 2] > oldsegbase) { 5384 dtv[i + 2] = olddtv[i + 2]; 5385 olddtv[i + 2] = 0; 5386 } 5387 } 5388 5389 /* 5390 * We assume that this block was the one we created with 5391 * allocate_initial_tls(). 5392 */ 5393 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5394 } else { 5395 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5396 if (obj->marker || obj->tlsoffset == 0) 5397 continue; 5398 addr = segbase - obj->tlsoffset; 5399 memset((void *)(addr + obj->tlsinitsize), 5400 0, obj->tlssize - obj->tlsinitsize); 5401 if (obj->tlsinit) { 5402 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5403 obj->static_tls_copied = true; 5404 } 5405 dtv[obj->tlsindex + 1] = addr; 5406 } 5407 } 5408 5409 return ((void *)segbase); 5410 } 5411 5412 void 5413 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5414 { 5415 Elf_Addr* dtv; 5416 size_t size, ralign; 5417 int dtvsize, i; 5418 Elf_Addr tlsstart, tlsend; 5419 5420 /* 5421 * Figure out the size of the initial TLS block so that we can 5422 * find stuff which ___tls_get_addr() allocated dynamically. 5423 */ 5424 ralign = tcbalign; 5425 if (tls_static_max_align > ralign) 5426 ralign = tls_static_max_align; 5427 size = roundup(tls_static_space, ralign); 5428 5429 dtv = ((Elf_Addr **)tls)[1]; 5430 dtvsize = dtv[1]; 5431 tlsend = (Elf_Addr)tls; 5432 tlsstart = tlsend - size; 5433 for (i = 0; i < dtvsize; i++) { 5434 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5435 dtv[i + 2] > tlsend)) { 5436 free_aligned((void *)dtv[i + 2]); 5437 } 5438 } 5439 5440 free_aligned((void *)tlsstart); 5441 free((void *)dtv); 5442 } 5443 5444 #endif /* TLS_VARIANT_II */ 5445 5446 /* 5447 * Allocate TLS block for module with given index. 5448 */ 5449 void * 5450 allocate_module_tls(int index) 5451 { 5452 Obj_Entry *obj; 5453 char *p; 5454 5455 TAILQ_FOREACH(obj, &obj_list, next) { 5456 if (obj->marker) 5457 continue; 5458 if (obj->tlsindex == index) 5459 break; 5460 } 5461 if (obj == NULL) { 5462 _rtld_error("Can't find module with TLS index %d", index); 5463 rtld_die(); 5464 } 5465 5466 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5467 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5468 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5469 return (p); 5470 } 5471 5472 bool 5473 allocate_tls_offset(Obj_Entry *obj) 5474 { 5475 size_t off; 5476 5477 if (obj->tls_done) 5478 return (true); 5479 5480 if (obj->tlssize == 0) { 5481 obj->tls_done = true; 5482 return (true); 5483 } 5484 5485 if (tls_last_offset == 0) 5486 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5487 obj->tlspoffset); 5488 else 5489 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5490 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5491 5492 obj->tlsoffset = off; 5493 #ifdef TLS_VARIANT_I 5494 off += obj->tlssize; 5495 #endif 5496 5497 /* 5498 * If we have already fixed the size of the static TLS block, we 5499 * must stay within that size. When allocating the static TLS, we 5500 * leave a small amount of space spare to be used for dynamically 5501 * loading modules which use static TLS. 5502 */ 5503 if (tls_static_space != 0) { 5504 if (off > tls_static_space) 5505 return (false); 5506 } else if (obj->tlsalign > tls_static_max_align) { 5507 tls_static_max_align = obj->tlsalign; 5508 } 5509 5510 tls_last_offset = off; 5511 tls_last_size = obj->tlssize; 5512 obj->tls_done = true; 5513 5514 return (true); 5515 } 5516 5517 void 5518 free_tls_offset(Obj_Entry *obj) 5519 { 5520 5521 /* 5522 * If we were the last thing to allocate out of the static TLS 5523 * block, we give our space back to the 'allocator'. This is a 5524 * simplistic workaround to allow libGL.so.1 to be loaded and 5525 * unloaded multiple times. 5526 */ 5527 size_t off = obj->tlsoffset; 5528 #ifdef TLS_VARIANT_I 5529 off += obj->tlssize; 5530 #endif 5531 if (off == tls_last_offset) { 5532 tls_last_offset -= obj->tlssize; 5533 tls_last_size = 0; 5534 } 5535 } 5536 5537 void * 5538 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5539 { 5540 void *ret; 5541 RtldLockState lockstate; 5542 5543 wlock_acquire(rtld_bind_lock, &lockstate); 5544 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5545 tcbsize, tcbalign); 5546 lock_release(rtld_bind_lock, &lockstate); 5547 return (ret); 5548 } 5549 5550 void 5551 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5552 { 5553 RtldLockState lockstate; 5554 5555 wlock_acquire(rtld_bind_lock, &lockstate); 5556 free_tls(tcb, tcbsize, tcbalign); 5557 lock_release(rtld_bind_lock, &lockstate); 5558 } 5559 5560 static void 5561 object_add_name(Obj_Entry *obj, const char *name) 5562 { 5563 Name_Entry *entry; 5564 size_t len; 5565 5566 len = strlen(name); 5567 entry = malloc(sizeof(Name_Entry) + len); 5568 5569 if (entry != NULL) { 5570 strcpy(entry->name, name); 5571 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5572 } 5573 } 5574 5575 static int 5576 object_match_name(const Obj_Entry *obj, const char *name) 5577 { 5578 Name_Entry *entry; 5579 5580 STAILQ_FOREACH(entry, &obj->names, link) { 5581 if (strcmp(name, entry->name) == 0) 5582 return (1); 5583 } 5584 return (0); 5585 } 5586 5587 static Obj_Entry * 5588 locate_dependency(const Obj_Entry *obj, const char *name) 5589 { 5590 const Objlist_Entry *entry; 5591 const Needed_Entry *needed; 5592 5593 STAILQ_FOREACH(entry, &list_main, link) { 5594 if (object_match_name(entry->obj, name)) 5595 return (entry->obj); 5596 } 5597 5598 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5599 if (strcmp(obj->strtab + needed->name, name) == 0 || 5600 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5601 /* 5602 * If there is DT_NEEDED for the name we are looking for, 5603 * we are all set. Note that object might not be found if 5604 * dependency was not loaded yet, so the function can 5605 * return NULL here. This is expected and handled 5606 * properly by the caller. 5607 */ 5608 return (needed->obj); 5609 } 5610 } 5611 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5612 obj->path, name); 5613 rtld_die(); 5614 } 5615 5616 static int 5617 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5618 const Elf_Vernaux *vna) 5619 { 5620 const Elf_Verdef *vd; 5621 const char *vername; 5622 5623 vername = refobj->strtab + vna->vna_name; 5624 vd = depobj->verdef; 5625 if (vd == NULL) { 5626 _rtld_error("%s: version %s required by %s not defined", 5627 depobj->path, vername, refobj->path); 5628 return (-1); 5629 } 5630 for (;;) { 5631 if (vd->vd_version != VER_DEF_CURRENT) { 5632 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5633 depobj->path, vd->vd_version); 5634 return (-1); 5635 } 5636 if (vna->vna_hash == vd->vd_hash) { 5637 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5638 ((const char *)vd + vd->vd_aux); 5639 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5640 return (0); 5641 } 5642 if (vd->vd_next == 0) 5643 break; 5644 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5645 } 5646 if (vna->vna_flags & VER_FLG_WEAK) 5647 return (0); 5648 _rtld_error("%s: version %s required by %s not found", 5649 depobj->path, vername, refobj->path); 5650 return (-1); 5651 } 5652 5653 static int 5654 rtld_verify_object_versions(Obj_Entry *obj) 5655 { 5656 const Elf_Verneed *vn; 5657 const Elf_Verdef *vd; 5658 const Elf_Verdaux *vda; 5659 const Elf_Vernaux *vna; 5660 const Obj_Entry *depobj; 5661 int maxvernum, vernum; 5662 5663 if (obj->ver_checked) 5664 return (0); 5665 obj->ver_checked = true; 5666 5667 maxvernum = 0; 5668 /* 5669 * Walk over defined and required version records and figure out 5670 * max index used by any of them. Do very basic sanity checking 5671 * while there. 5672 */ 5673 vn = obj->verneed; 5674 while (vn != NULL) { 5675 if (vn->vn_version != VER_NEED_CURRENT) { 5676 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5677 obj->path, vn->vn_version); 5678 return (-1); 5679 } 5680 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5681 for (;;) { 5682 vernum = VER_NEED_IDX(vna->vna_other); 5683 if (vernum > maxvernum) 5684 maxvernum = vernum; 5685 if (vna->vna_next == 0) 5686 break; 5687 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5688 } 5689 if (vn->vn_next == 0) 5690 break; 5691 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5692 } 5693 5694 vd = obj->verdef; 5695 while (vd != NULL) { 5696 if (vd->vd_version != VER_DEF_CURRENT) { 5697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5698 obj->path, vd->vd_version); 5699 return (-1); 5700 } 5701 vernum = VER_DEF_IDX(vd->vd_ndx); 5702 if (vernum > maxvernum) 5703 maxvernum = vernum; 5704 if (vd->vd_next == 0) 5705 break; 5706 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5707 } 5708 5709 if (maxvernum == 0) 5710 return (0); 5711 5712 /* 5713 * Store version information in array indexable by version index. 5714 * Verify that object version requirements are satisfied along the 5715 * way. 5716 */ 5717 obj->vernum = maxvernum + 1; 5718 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5719 5720 vd = obj->verdef; 5721 while (vd != NULL) { 5722 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5723 vernum = VER_DEF_IDX(vd->vd_ndx); 5724 assert(vernum <= maxvernum); 5725 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5726 obj->vertab[vernum].hash = vd->vd_hash; 5727 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5728 obj->vertab[vernum].file = NULL; 5729 obj->vertab[vernum].flags = 0; 5730 } 5731 if (vd->vd_next == 0) 5732 break; 5733 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5734 } 5735 5736 vn = obj->verneed; 5737 while (vn != NULL) { 5738 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5739 if (depobj == NULL) 5740 return (-1); 5741 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5742 for (;;) { 5743 if (check_object_provided_version(obj, depobj, vna)) 5744 return (-1); 5745 vernum = VER_NEED_IDX(vna->vna_other); 5746 assert(vernum <= maxvernum); 5747 obj->vertab[vernum].hash = vna->vna_hash; 5748 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5749 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5750 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5751 VER_INFO_HIDDEN : 0; 5752 if (vna->vna_next == 0) 5753 break; 5754 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5755 } 5756 if (vn->vn_next == 0) 5757 break; 5758 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5759 } 5760 return (0); 5761 } 5762 5763 static int 5764 rtld_verify_versions(const Objlist *objlist) 5765 { 5766 Objlist_Entry *entry; 5767 int rc; 5768 5769 rc = 0; 5770 STAILQ_FOREACH(entry, objlist, link) { 5771 /* 5772 * Skip dummy objects or objects that have their version requirements 5773 * already checked. 5774 */ 5775 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5776 continue; 5777 if (rtld_verify_object_versions(entry->obj) == -1) { 5778 rc = -1; 5779 if (ld_tracing == NULL) 5780 break; 5781 } 5782 } 5783 if (rc == 0 || ld_tracing != NULL) 5784 rc = rtld_verify_object_versions(&obj_rtld); 5785 return (rc); 5786 } 5787 5788 const Ver_Entry * 5789 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5790 { 5791 Elf_Versym vernum; 5792 5793 if (obj->vertab) { 5794 vernum = VER_NDX(obj->versyms[symnum]); 5795 if (vernum >= obj->vernum) { 5796 _rtld_error("%s: symbol %s has wrong verneed value %d", 5797 obj->path, obj->strtab + symnum, vernum); 5798 } else if (obj->vertab[vernum].hash != 0) { 5799 return (&obj->vertab[vernum]); 5800 } 5801 } 5802 return (NULL); 5803 } 5804 5805 int 5806 _rtld_get_stack_prot(void) 5807 { 5808 5809 return (stack_prot); 5810 } 5811 5812 int 5813 _rtld_is_dlopened(void *arg) 5814 { 5815 Obj_Entry *obj; 5816 RtldLockState lockstate; 5817 int res; 5818 5819 rlock_acquire(rtld_bind_lock, &lockstate); 5820 obj = dlcheck(arg); 5821 if (obj == NULL) 5822 obj = obj_from_addr(arg); 5823 if (obj == NULL) { 5824 _rtld_error("No shared object contains address"); 5825 lock_release(rtld_bind_lock, &lockstate); 5826 return (-1); 5827 } 5828 res = obj->dlopened ? 1 : 0; 5829 lock_release(rtld_bind_lock, &lockstate); 5830 return (res); 5831 } 5832 5833 static int 5834 obj_remap_relro(Obj_Entry *obj, int prot) 5835 { 5836 5837 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5838 prot) == -1) { 5839 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5840 obj->path, prot, rtld_strerror(errno)); 5841 return (-1); 5842 } 5843 return (0); 5844 } 5845 5846 static int 5847 obj_disable_relro(Obj_Entry *obj) 5848 { 5849 5850 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5851 } 5852 5853 static int 5854 obj_enforce_relro(Obj_Entry *obj) 5855 { 5856 5857 return (obj_remap_relro(obj, PROT_READ)); 5858 } 5859 5860 static void 5861 map_stacks_exec(RtldLockState *lockstate) 5862 { 5863 void (*thr_map_stacks_exec)(void); 5864 5865 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5866 return; 5867 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5868 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5869 if (thr_map_stacks_exec != NULL) { 5870 stack_prot |= PROT_EXEC; 5871 thr_map_stacks_exec(); 5872 } 5873 } 5874 5875 static void 5876 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5877 { 5878 Objlist_Entry *elm; 5879 Obj_Entry *obj; 5880 void (*distrib)(size_t, void *, size_t, size_t); 5881 5882 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5883 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5884 if (distrib == NULL) 5885 return; 5886 STAILQ_FOREACH(elm, list, link) { 5887 obj = elm->obj; 5888 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5889 continue; 5890 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5891 obj->tlssize); 5892 obj->static_tls_copied = true; 5893 } 5894 } 5895 5896 void 5897 symlook_init(SymLook *dst, const char *name) 5898 { 5899 5900 bzero(dst, sizeof(*dst)); 5901 dst->name = name; 5902 dst->hash = elf_hash(name); 5903 dst->hash_gnu = gnu_hash(name); 5904 } 5905 5906 static void 5907 symlook_init_from_req(SymLook *dst, const SymLook *src) 5908 { 5909 5910 dst->name = src->name; 5911 dst->hash = src->hash; 5912 dst->hash_gnu = src->hash_gnu; 5913 dst->ventry = src->ventry; 5914 dst->flags = src->flags; 5915 dst->defobj_out = NULL; 5916 dst->sym_out = NULL; 5917 dst->lockstate = src->lockstate; 5918 } 5919 5920 static int 5921 open_binary_fd(const char *argv0, bool search_in_path, 5922 const char **binpath_res) 5923 { 5924 char *binpath, *pathenv, *pe, *res1; 5925 const char *res; 5926 int fd; 5927 5928 binpath = NULL; 5929 res = NULL; 5930 if (search_in_path && strchr(argv0, '/') == NULL) { 5931 binpath = xmalloc(PATH_MAX); 5932 pathenv = getenv("PATH"); 5933 if (pathenv == NULL) { 5934 _rtld_error("-p and no PATH environment variable"); 5935 rtld_die(); 5936 } 5937 pathenv = strdup(pathenv); 5938 if (pathenv == NULL) { 5939 _rtld_error("Cannot allocate memory"); 5940 rtld_die(); 5941 } 5942 fd = -1; 5943 errno = ENOENT; 5944 while ((pe = strsep(&pathenv, ":")) != NULL) { 5945 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5946 continue; 5947 if (binpath[0] != '\0' && 5948 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5949 continue; 5950 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5951 continue; 5952 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5953 if (fd != -1 || errno != ENOENT) { 5954 res = binpath; 5955 break; 5956 } 5957 } 5958 free(pathenv); 5959 } else { 5960 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5961 res = argv0; 5962 } 5963 5964 if (fd == -1) { 5965 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5966 rtld_die(); 5967 } 5968 if (res != NULL && res[0] != '/') { 5969 res1 = xmalloc(PATH_MAX); 5970 if (realpath(res, res1) != NULL) { 5971 if (res != argv0) 5972 free(__DECONST(char *, res)); 5973 res = res1; 5974 } else { 5975 free(res1); 5976 } 5977 } 5978 *binpath_res = res; 5979 return (fd); 5980 } 5981 5982 /* 5983 * Parse a set of command-line arguments. 5984 */ 5985 static int 5986 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5987 const char **argv0, bool *dir_ignore) 5988 { 5989 const char *arg; 5990 char machine[64]; 5991 size_t sz; 5992 int arglen, fd, i, j, mib[2]; 5993 char opt; 5994 bool seen_b, seen_f; 5995 5996 dbg("Parsing command-line arguments"); 5997 *use_pathp = false; 5998 *fdp = -1; 5999 *dir_ignore = false; 6000 seen_b = seen_f = false; 6001 6002 for (i = 1; i < argc; i++ ) { 6003 arg = argv[i]; 6004 dbg("argv[%d]: '%s'", i, arg); 6005 6006 /* 6007 * rtld arguments end with an explicit "--" or with the first 6008 * non-prefixed argument. 6009 */ 6010 if (strcmp(arg, "--") == 0) { 6011 i++; 6012 break; 6013 } 6014 if (arg[0] != '-') 6015 break; 6016 6017 /* 6018 * All other arguments are single-character options that can 6019 * be combined, so we need to search through `arg` for them. 6020 */ 6021 arglen = strlen(arg); 6022 for (j = 1; j < arglen; j++) { 6023 opt = arg[j]; 6024 if (opt == 'h') { 6025 print_usage(argv[0]); 6026 _exit(0); 6027 } else if (opt == 'b') { 6028 if (seen_f) { 6029 _rtld_error("Both -b and -f specified"); 6030 rtld_die(); 6031 } 6032 if (j != arglen - 1) { 6033 _rtld_error("Invalid options: %s", arg); 6034 rtld_die(); 6035 } 6036 i++; 6037 *argv0 = argv[i]; 6038 seen_b = true; 6039 break; 6040 } else if (opt == 'd') { 6041 *dir_ignore = true; 6042 } else if (opt == 'f') { 6043 if (seen_b) { 6044 _rtld_error("Both -b and -f specified"); 6045 rtld_die(); 6046 } 6047 6048 /* 6049 * -f XX can be used to specify a 6050 * descriptor for the binary named at 6051 * the command line (i.e., the later 6052 * argument will specify the process 6053 * name but the descriptor is what 6054 * will actually be executed). 6055 * 6056 * -f must be the last option in the 6057 * group, e.g., -abcf <fd>. 6058 */ 6059 if (j != arglen - 1) { 6060 _rtld_error("Invalid options: %s", arg); 6061 rtld_die(); 6062 } 6063 i++; 6064 fd = parse_integer(argv[i]); 6065 if (fd == -1) { 6066 _rtld_error( 6067 "Invalid file descriptor: '%s'", 6068 argv[i]); 6069 rtld_die(); 6070 } 6071 *fdp = fd; 6072 seen_f = true; 6073 break; 6074 } else if (opt == 'p') { 6075 *use_pathp = true; 6076 } else if (opt == 'u') { 6077 trust = false; 6078 } else if (opt == 'v') { 6079 machine[0] = '\0'; 6080 mib[0] = CTL_HW; 6081 mib[1] = HW_MACHINE; 6082 sz = sizeof(machine); 6083 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6084 ld_elf_hints_path = ld_get_env_var( 6085 LD_ELF_HINTS_PATH); 6086 set_ld_elf_hints_path(); 6087 rtld_printf( 6088 "FreeBSD ld-elf.so.1 %s\n" 6089 "FreeBSD_version %d\n" 6090 "Default lib path %s\n" 6091 "Hints lib path %s\n" 6092 "Env prefix %s\n" 6093 "Default hint file %s\n" 6094 "Hint file %s\n" 6095 "libmap file %s\n", 6096 machine, 6097 __FreeBSD_version, ld_standard_library_path, 6098 gethints(false), 6099 ld_env_prefix, ld_elf_hints_default, 6100 ld_elf_hints_path, 6101 ld_path_libmap_conf); 6102 _exit(0); 6103 } else { 6104 _rtld_error("Invalid argument: '%s'", arg); 6105 print_usage(argv[0]); 6106 rtld_die(); 6107 } 6108 } 6109 } 6110 6111 if (!seen_b) 6112 *argv0 = argv[i]; 6113 return (i); 6114 } 6115 6116 /* 6117 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6118 */ 6119 static int 6120 parse_integer(const char *str) 6121 { 6122 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6123 const char *orig; 6124 int n; 6125 char c; 6126 6127 orig = str; 6128 n = 0; 6129 for (c = *str; c != '\0'; c = *++str) { 6130 if (c < '0' || c > '9') 6131 return (-1); 6132 6133 n *= RADIX; 6134 n += c - '0'; 6135 } 6136 6137 /* Make sure we actually parsed something. */ 6138 if (str == orig) 6139 return (-1); 6140 return (n); 6141 } 6142 6143 static void 6144 print_usage(const char *argv0) 6145 { 6146 6147 rtld_printf( 6148 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6149 "\n" 6150 "Options:\n" 6151 " -h Display this help message\n" 6152 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6153 " -d Ignore lack of exec permissions for the binary\n" 6154 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6155 " -p Search in PATH for named binary\n" 6156 " -u Ignore LD_ environment variables\n" 6157 " -v Display identification information\n" 6158 " -- End of RTLD options\n" 6159 " <binary> Name of process to execute\n" 6160 " <args> Arguments to the executed process\n", argv0); 6161 } 6162 6163 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6164 static const struct auxfmt { 6165 const char *name; 6166 const char *fmt; 6167 } auxfmts[] = { 6168 AUXFMT(AT_NULL, NULL), 6169 AUXFMT(AT_IGNORE, NULL), 6170 AUXFMT(AT_EXECFD, "%ld"), 6171 AUXFMT(AT_PHDR, "%p"), 6172 AUXFMT(AT_PHENT, "%lu"), 6173 AUXFMT(AT_PHNUM, "%lu"), 6174 AUXFMT(AT_PAGESZ, "%lu"), 6175 AUXFMT(AT_BASE, "%#lx"), 6176 AUXFMT(AT_FLAGS, "%#lx"), 6177 AUXFMT(AT_ENTRY, "%p"), 6178 AUXFMT(AT_NOTELF, NULL), 6179 AUXFMT(AT_UID, "%ld"), 6180 AUXFMT(AT_EUID, "%ld"), 6181 AUXFMT(AT_GID, "%ld"), 6182 AUXFMT(AT_EGID, "%ld"), 6183 AUXFMT(AT_EXECPATH, "%s"), 6184 AUXFMT(AT_CANARY, "%p"), 6185 AUXFMT(AT_CANARYLEN, "%lu"), 6186 AUXFMT(AT_OSRELDATE, "%lu"), 6187 AUXFMT(AT_NCPUS, "%lu"), 6188 AUXFMT(AT_PAGESIZES, "%p"), 6189 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6190 AUXFMT(AT_TIMEKEEP, "%p"), 6191 AUXFMT(AT_STACKPROT, "%#lx"), 6192 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6193 AUXFMT(AT_HWCAP, "%#lx"), 6194 AUXFMT(AT_HWCAP2, "%#lx"), 6195 AUXFMT(AT_BSDFLAGS, "%#lx"), 6196 AUXFMT(AT_ARGC, "%lu"), 6197 AUXFMT(AT_ARGV, "%p"), 6198 AUXFMT(AT_ENVC, "%p"), 6199 AUXFMT(AT_ENVV, "%p"), 6200 AUXFMT(AT_PS_STRINGS, "%p"), 6201 AUXFMT(AT_FXRNG, "%p"), 6202 AUXFMT(AT_KPRELOAD, "%p"), 6203 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6204 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6205 }; 6206 6207 static bool 6208 is_ptr_fmt(const char *fmt) 6209 { 6210 char last; 6211 6212 last = fmt[strlen(fmt) - 1]; 6213 return (last == 'p' || last == 's'); 6214 } 6215 6216 static void 6217 dump_auxv(Elf_Auxinfo **aux_info) 6218 { 6219 Elf_Auxinfo *auxp; 6220 const struct auxfmt *fmt; 6221 int i; 6222 6223 for (i = 0; i < AT_COUNT; i++) { 6224 auxp = aux_info[i]; 6225 if (auxp == NULL) 6226 continue; 6227 fmt = &auxfmts[i]; 6228 if (fmt->fmt == NULL) 6229 continue; 6230 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6231 if (is_ptr_fmt(fmt->fmt)) { 6232 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6233 auxp->a_un.a_ptr); 6234 } else { 6235 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6236 auxp->a_un.a_val); 6237 } 6238 rtld_fdprintf(STDOUT_FILENO, "\n"); 6239 } 6240 } 6241 6242 /* 6243 * Overrides for libc_pic-provided functions. 6244 */ 6245 6246 int 6247 __getosreldate(void) 6248 { 6249 size_t len; 6250 int oid[2]; 6251 int error, osrel; 6252 6253 if (osreldate != 0) 6254 return (osreldate); 6255 6256 oid[0] = CTL_KERN; 6257 oid[1] = KERN_OSRELDATE; 6258 osrel = 0; 6259 len = sizeof(osrel); 6260 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6261 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6262 osreldate = osrel; 6263 return (osreldate); 6264 } 6265 const char * 6266 rtld_strerror(int errnum) 6267 { 6268 6269 if (errnum < 0 || errnum >= sys_nerr) 6270 return ("Unknown error"); 6271 return (sys_errlist[errnum]); 6272 } 6273 6274 char * 6275 getenv(const char *name) 6276 { 6277 return (__DECONST(char *, rtld_get_env_val(environ, name, 6278 strlen(name)))); 6279 } 6280 6281 /* malloc */ 6282 void * 6283 malloc(size_t nbytes) 6284 { 6285 6286 return (__crt_malloc(nbytes)); 6287 } 6288 6289 void * 6290 calloc(size_t num, size_t size) 6291 { 6292 6293 return (__crt_calloc(num, size)); 6294 } 6295 6296 void 6297 free(void *cp) 6298 { 6299 6300 __crt_free(cp); 6301 } 6302 6303 void * 6304 realloc(void *cp, size_t nbytes) 6305 { 6306 6307 return (__crt_realloc(cp, nbytes)); 6308 } 6309 6310 extern int _rtld_version__FreeBSD_version __exported; 6311 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6312 6313 extern char _rtld_version_laddr_offset __exported; 6314 char _rtld_version_laddr_offset; 6315 6316 extern char _rtld_version_dlpi_tls_data __exported; 6317 char _rtld_version_dlpi_tls_data; 6318