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 <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 __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 errmsg_restore(struct dlerror_save *); 108 static struct dlerror_save *errmsg_save(void); 109 static void *fill_search_info(const char *, size_t, void *); 110 static char *find_library(const char *, const Obj_Entry *, int *); 111 static const char *gethints(bool); 112 static void hold_object(Obj_Entry *); 113 static void unhold_object(Obj_Entry *); 114 static void init_dag(Obj_Entry *); 115 static void init_marker(Obj_Entry *); 116 static void init_pagesizes(Elf_Auxinfo **aux_info); 117 static void init_rtld(caddr_t, Elf_Auxinfo **); 118 static void initlist_add_neededs(Needed_Entry *, Objlist *); 119 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 120 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 121 static void linkmap_add(Obj_Entry *); 122 static void linkmap_delete(Obj_Entry *); 123 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 124 static void unload_filtees(Obj_Entry *, RtldLockState *); 125 static int load_needed_objects(Obj_Entry *, int); 126 static int load_preload_objects(const char *, bool); 127 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 128 static void map_stacks_exec(RtldLockState *); 129 static int obj_disable_relro(Obj_Entry *); 130 static int obj_enforce_relro(Obj_Entry *); 131 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 132 static void objlist_call_init(Objlist *, RtldLockState *); 133 static void objlist_clear(Objlist *); 134 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 135 static void objlist_init(Objlist *); 136 static void objlist_push_head(Objlist *, Obj_Entry *); 137 static void objlist_push_tail(Objlist *, Obj_Entry *); 138 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 139 static void objlist_remove(Objlist *, Obj_Entry *); 140 static int open_binary_fd(const char *argv0, bool search_in_path, 141 const char **binpath_res); 142 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 143 const char **argv0, bool *dir_ignore); 144 static int parse_integer(const char *); 145 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 146 static void print_usage(const char *argv0); 147 static void release_object(Obj_Entry *); 148 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 149 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 150 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 151 int flags, RtldLockState *lockstate); 152 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 153 RtldLockState *); 154 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 155 static int rtld_dirname(const char *, char *); 156 static int rtld_dirname_abs(const char *, char *); 157 static void *rtld_dlopen(const char *name, int fd, int mode); 158 static void rtld_exit(void); 159 static void rtld_nop_exit(void); 160 static char *search_library_path(const char *, const char *, const char *, 161 int *); 162 static char *search_library_pathfds(const char *, const char *, int *); 163 static const void **get_program_var_addr(const char *, RtldLockState *); 164 static void set_program_var(const char *, const void *); 165 static int symlook_default(SymLook *, const Obj_Entry *refobj); 166 static int symlook_global(SymLook *, DoneList *); 167 static void symlook_init_from_req(SymLook *, const SymLook *); 168 static int symlook_list(SymLook *, const Objlist *, DoneList *); 169 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 170 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 171 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 172 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 173 static void trace_loaded_objects(Obj_Entry *); 174 static void unlink_object(Obj_Entry *); 175 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 176 static void unref_dag(Obj_Entry *); 177 static void ref_dag(Obj_Entry *); 178 static char *origin_subst_one(Obj_Entry *, char *, const char *, 179 const char *, bool); 180 static char *origin_subst(Obj_Entry *, const char *); 181 static bool obj_resolve_origin(Obj_Entry *obj); 182 static void preinit_main(void); 183 static int rtld_verify_versions(const Objlist *); 184 static int rtld_verify_object_versions(Obj_Entry *); 185 static void object_add_name(Obj_Entry *, const char *); 186 static int object_match_name(const Obj_Entry *, const char *); 187 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 188 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 189 struct dl_phdr_info *phdr_info); 190 static uint32_t gnu_hash(const char *); 191 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 192 const unsigned long); 193 194 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 195 void _r_debug_postinit(struct link_map *) __noinline __exported; 196 197 int __sys_openat(int, const char *, int, ...); 198 199 /* 200 * Data declarations. 201 */ 202 struct r_debug r_debug __exported; /* for GDB; */ 203 static bool libmap_disable; /* Disable libmap */ 204 static bool ld_loadfltr; /* Immediate filters processing */ 205 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 206 static bool trust; /* False for setuid and setgid programs */ 207 static bool dangerous_ld_env; /* True if environment variables have been 208 used to affect the libraries loaded */ 209 bool ld_bind_not; /* Disable PLT update */ 210 static const char *ld_bind_now; /* Environment variable for immediate binding */ 211 static const char *ld_debug; /* Environment variable for debugging */ 212 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 213 weak definition */ 214 static const char *ld_library_path;/* Environment variable for search path */ 215 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 216 static const char *ld_preload; /* Environment variable for libraries to 217 load first */ 218 static const char *ld_preload_fds;/* Environment variable for libraries represented by 219 descriptors */ 220 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 221 static const char *ld_tracing; /* Called from ldd to print libs */ 222 static const char *ld_utrace; /* Use utrace() to log events. */ 223 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 224 static Obj_Entry *obj_main; /* The main program shared object */ 225 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 226 static unsigned int obj_count; /* Number of objects in obj_list */ 227 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 228 229 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 230 STAILQ_HEAD_INITIALIZER(list_global); 231 static Objlist list_main = /* Objects loaded at program startup */ 232 STAILQ_HEAD_INITIALIZER(list_main); 233 static Objlist list_fini = /* Objects needing fini() calls */ 234 STAILQ_HEAD_INITIALIZER(list_fini); 235 236 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 237 238 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 239 240 extern Elf_Dyn _DYNAMIC; 241 #pragma weak _DYNAMIC 242 243 int dlclose(void *) __exported; 244 char *dlerror(void) __exported; 245 void *dlopen(const char *, int) __exported; 246 void *fdlopen(int, int) __exported; 247 void *dlsym(void *, const char *) __exported; 248 dlfunc_t dlfunc(void *, const char *) __exported; 249 void *dlvsym(void *, const char *, const char *) __exported; 250 int dladdr(const void *, Dl_info *) __exported; 251 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 252 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 253 int dlinfo(void *, int , void *) __exported; 254 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 255 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 256 int _rtld_get_stack_prot(void) __exported; 257 int _rtld_is_dlopened(void *) __exported; 258 void _rtld_error(const char *, ...) __exported; 259 260 /* Only here to fix -Wmissing-prototypes warnings */ 261 int __getosreldate(void); 262 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 263 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 264 265 266 int npagesizes; 267 static int osreldate; 268 size_t *pagesizes; 269 270 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 271 static int max_stack_flags; 272 273 /* 274 * Global declarations normally provided by crt1. The dynamic linker is 275 * not built with crt1, so we have to provide them ourselves. 276 */ 277 char *__progname; 278 char **environ; 279 280 /* 281 * Used to pass argc, argv to init functions. 282 */ 283 int main_argc; 284 char **main_argv; 285 286 /* 287 * Globals to control TLS allocation. 288 */ 289 size_t tls_last_offset; /* Static TLS offset of last module */ 290 size_t tls_last_size; /* Static TLS size of last module */ 291 size_t tls_static_space; /* Static TLS space allocated */ 292 static size_t tls_static_max_align; 293 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 294 int tls_max_index = 1; /* Largest module index allocated */ 295 296 static bool ld_library_path_rpath = false; 297 bool ld_fast_sigblock = false; 298 299 /* 300 * Globals for path names, and such 301 */ 302 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 303 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 304 const char *ld_path_rtld = _PATH_RTLD; 305 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 306 const char *ld_env_prefix = LD_; 307 308 static void (*rtld_exit_ptr)(void); 309 310 /* 311 * Fill in a DoneList with an allocation large enough to hold all of 312 * the currently-loaded objects. Keep this as a macro since it calls 313 * alloca and we want that to occur within the scope of the caller. 314 */ 315 #define donelist_init(dlp) \ 316 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 317 assert((dlp)->objs != NULL), \ 318 (dlp)->num_alloc = obj_count, \ 319 (dlp)->num_used = 0) 320 321 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 322 if (ld_utrace != NULL) \ 323 ld_utrace_log(e, h, mb, ms, r, n); \ 324 } while (0) 325 326 static void 327 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 328 int refcnt, const char *name) 329 { 330 struct utrace_rtld ut; 331 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 332 333 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 334 ut.event = event; 335 ut.handle = handle; 336 ut.mapbase = mapbase; 337 ut.mapsize = mapsize; 338 ut.refcnt = refcnt; 339 bzero(ut.name, sizeof(ut.name)); 340 if (name) 341 strlcpy(ut.name, name, sizeof(ut.name)); 342 utrace(&ut, sizeof(ut)); 343 } 344 345 enum { 346 LD_BIND_NOW = 0, 347 LD_PRELOAD, 348 LD_LIBMAP, 349 LD_LIBRARY_PATH, 350 LD_LIBRARY_PATH_FDS, 351 LD_LIBMAP_DISABLE, 352 LD_BIND_NOT, 353 LD_DEBUG, 354 LD_ELF_HINTS_PATH, 355 LD_LOADFLTR, 356 LD_LIBRARY_PATH_RPATH, 357 LD_PRELOAD_FDS, 358 LD_DYNAMIC_WEAK, 359 LD_TRACE_LOADED_OBJECTS, 360 LD_UTRACE, 361 LD_DUMP_REL_PRE, 362 LD_DUMP_REL_POST, 363 LD_TRACE_LOADED_OBJECTS_PROGNAME, 364 LD_TRACE_LOADED_OBJECTS_FMT1, 365 LD_TRACE_LOADED_OBJECTS_FMT2, 366 LD_TRACE_LOADED_OBJECTS_ALL, 367 }; 368 369 struct ld_env_var_desc { 370 const char * const n; 371 const char *val; 372 const bool unsecure; 373 }; 374 #define LD_ENV_DESC(var, unsec) \ 375 [LD_##var] = { .n = #var, .unsecure = unsec } 376 377 static struct ld_env_var_desc ld_env_vars[] = { 378 LD_ENV_DESC(BIND_NOW, false), 379 LD_ENV_DESC(PRELOAD, true), 380 LD_ENV_DESC(LIBMAP, true), 381 LD_ENV_DESC(LIBRARY_PATH, true), 382 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 383 LD_ENV_DESC(LIBMAP_DISABLE, true), 384 LD_ENV_DESC(BIND_NOT, true), 385 LD_ENV_DESC(DEBUG, true), 386 LD_ENV_DESC(ELF_HINTS_PATH, true), 387 LD_ENV_DESC(LOADFLTR, true), 388 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 389 LD_ENV_DESC(PRELOAD_FDS, true), 390 LD_ENV_DESC(DYNAMIC_WEAK, true), 391 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 392 LD_ENV_DESC(UTRACE, false), 393 LD_ENV_DESC(DUMP_REL_PRE, false), 394 LD_ENV_DESC(DUMP_REL_POST, false), 395 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 396 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 397 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 399 }; 400 401 static const char * 402 ld_get_env_var(int idx) 403 { 404 return (ld_env_vars[idx].val); 405 } 406 407 static const char * 408 rtld_get_env_val(char **env, const char *name, size_t name_len) 409 { 410 char **m, *n, *v; 411 412 for (m = env; *m != NULL; m++) { 413 n = *m; 414 v = strchr(n, '='); 415 if (v == NULL) { 416 /* corrupt environment? */ 417 continue; 418 } 419 if (v - n == (ptrdiff_t)name_len && 420 strncmp(name, n, name_len) == 0) 421 return (v + 1); 422 } 423 return (NULL); 424 } 425 426 static void 427 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 428 { 429 struct ld_env_var_desc *lvd; 430 size_t prefix_len, nlen; 431 char **m, *n, *v; 432 int i; 433 434 prefix_len = strlen(env_prefix); 435 for (m = env; *m != NULL; m++) { 436 n = *m; 437 if (strncmp(env_prefix, n, prefix_len) != 0) { 438 /* Not a rtld environment variable. */ 439 continue; 440 } 441 n += prefix_len; 442 v = strchr(n, '='); 443 if (v == NULL) { 444 /* corrupt environment? */ 445 continue; 446 } 447 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 448 lvd = &ld_env_vars[i]; 449 if (lvd->val != NULL) { 450 /* Saw higher-priority variable name already. */ 451 continue; 452 } 453 nlen = strlen(lvd->n); 454 if (v - n == (ptrdiff_t)nlen && 455 strncmp(lvd->n, n, nlen) == 0) { 456 lvd->val = v + 1; 457 break; 458 } 459 } 460 } 461 } 462 463 static void 464 rtld_init_env_vars(char **env) 465 { 466 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 467 } 468 469 static void 470 set_ld_elf_hints_path(void) 471 { 472 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 473 ld_elf_hints_path = ld_elf_hints_default; 474 } 475 476 /* 477 * Main entry point for dynamic linking. The first argument is the 478 * stack pointer. The stack is expected to be laid out as described 479 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 480 * Specifically, the stack pointer points to a word containing 481 * ARGC. Following that in the stack is a null-terminated sequence 482 * of pointers to argument strings. Then comes a null-terminated 483 * sequence of pointers to environment strings. Finally, there is a 484 * sequence of "auxiliary vector" entries. 485 * 486 * The second argument points to a place to store the dynamic linker's 487 * exit procedure pointer and the third to a place to store the main 488 * program's object. 489 * 490 * The return value is the main program's entry point. 491 */ 492 func_ptr_type 493 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 494 { 495 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 496 Objlist_Entry *entry; 497 Obj_Entry *last_interposer, *obj, *preload_tail; 498 const Elf_Phdr *phdr; 499 Objlist initlist; 500 RtldLockState lockstate; 501 struct stat st; 502 Elf_Addr *argcp; 503 char **argv, **env, **envp, *kexecpath; 504 const char *argv0, *binpath, *library_path_rpath; 505 struct ld_env_var_desc *lvd; 506 caddr_t imgentry; 507 char buf[MAXPATHLEN]; 508 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 509 size_t sz; 510 #ifdef __powerpc__ 511 int old_auxv_format = 1; 512 #endif 513 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 514 515 /* 516 * On entry, the dynamic linker itself has not been relocated yet. 517 * Be very careful not to reference any global data until after 518 * init_rtld has returned. It is OK to reference file-scope statics 519 * and string constants, and to call static and global functions. 520 */ 521 522 /* Find the auxiliary vector on the stack. */ 523 argcp = sp; 524 argc = *sp++; 525 argv = (char **) sp; 526 sp += argc + 1; /* Skip over arguments and NULL terminator */ 527 env = (char **) sp; 528 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 529 ; 530 aux = (Elf_Auxinfo *) sp; 531 532 /* Digest the auxiliary vector. */ 533 for (i = 0; i < AT_COUNT; i++) 534 aux_info[i] = NULL; 535 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 536 if (auxp->a_type < AT_COUNT) 537 aux_info[auxp->a_type] = auxp; 538 #ifdef __powerpc__ 539 if (auxp->a_type == 23) /* AT_STACKPROT */ 540 old_auxv_format = 0; 541 #endif 542 } 543 544 #ifdef __powerpc__ 545 if (old_auxv_format) { 546 /* Remap from old-style auxv numbers. */ 547 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 548 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 549 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 550 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 551 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 552 aux_info[13] = NULL; /* AT_GID */ 553 554 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 555 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 556 aux_info[16] = aux_info[14]; /* AT_CANARY */ 557 aux_info[14] = NULL; /* AT_EGID */ 558 } 559 #endif 560 561 /* Initialize and relocate ourselves. */ 562 assert(aux_info[AT_BASE] != NULL); 563 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 564 565 dlerror_dflt_init(); 566 567 __progname = obj_rtld.path; 568 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 569 environ = env; 570 main_argc = argc; 571 main_argv = argv; 572 573 if (aux_info[AT_BSDFLAGS] != NULL && 574 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 575 ld_fast_sigblock = true; 576 577 trust = !issetugid(); 578 direct_exec = false; 579 580 md_abi_variant_hook(aux_info); 581 rtld_init_env_vars(env); 582 583 fd = -1; 584 if (aux_info[AT_EXECFD] != NULL) { 585 fd = aux_info[AT_EXECFD]->a_un.a_val; 586 } else { 587 assert(aux_info[AT_PHDR] != NULL); 588 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 589 if (phdr == obj_rtld.phdr) { 590 if (!trust) { 591 _rtld_error("Tainted process refusing to run binary %s", 592 argv0); 593 rtld_die(); 594 } 595 direct_exec = true; 596 597 dbg("opening main program in direct exec mode"); 598 if (argc >= 2) { 599 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 600 &argv0, &dir_ignore); 601 explicit_fd = (fd != -1); 602 binpath = NULL; 603 if (!explicit_fd) 604 fd = open_binary_fd(argv0, search_in_path, &binpath); 605 if (fstat(fd, &st) == -1) { 606 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 607 explicit_fd ? "user-provided descriptor" : argv0, 608 rtld_strerror(errno)); 609 rtld_die(); 610 } 611 612 /* 613 * Rough emulation of the permission checks done by 614 * execve(2), only Unix DACs are checked, ACLs are 615 * ignored. Preserve the semantic of disabling owner 616 * to execute if owner x bit is cleared, even if 617 * others x bit is enabled. 618 * mmap(2) does not allow to mmap with PROT_EXEC if 619 * binary' file comes from noexec mount. We cannot 620 * set a text reference on the binary. 621 */ 622 dir_enable = false; 623 if (st.st_uid == geteuid()) { 624 if ((st.st_mode & S_IXUSR) != 0) 625 dir_enable = true; 626 } else if (st.st_gid == getegid()) { 627 if ((st.st_mode & S_IXGRP) != 0) 628 dir_enable = true; 629 } else if ((st.st_mode & S_IXOTH) != 0) { 630 dir_enable = true; 631 } 632 if (!dir_enable && !dir_ignore) { 633 _rtld_error("No execute permission for binary %s", 634 argv0); 635 rtld_die(); 636 } 637 638 /* 639 * For direct exec mode, argv[0] is the interpreter 640 * name, we must remove it and shift arguments left 641 * before invoking binary main. Since stack layout 642 * places environment pointers and aux vectors right 643 * after the terminating NULL, we must shift 644 * environment and aux as well. 645 */ 646 main_argc = argc - rtld_argc; 647 for (i = 0; i <= main_argc; i++) 648 argv[i] = argv[i + rtld_argc]; 649 *argcp -= rtld_argc; 650 environ = env = envp = argv + main_argc + 1; 651 dbg("move env from %p to %p", envp + rtld_argc, envp); 652 do { 653 *envp = *(envp + rtld_argc); 654 } while (*envp++ != NULL); 655 aux = auxp = (Elf_Auxinfo *)envp; 656 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 657 dbg("move aux from %p to %p", auxpf, aux); 658 /* XXXKIB insert place for AT_EXECPATH if not present */ 659 for (;; auxp++, auxpf++) { 660 *auxp = *auxpf; 661 if (auxp->a_type == AT_NULL) 662 break; 663 } 664 /* Since the auxiliary vector has moved, redigest it. */ 665 for (i = 0; i < AT_COUNT; i++) 666 aux_info[i] = NULL; 667 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 668 if (auxp->a_type < AT_COUNT) 669 aux_info[auxp->a_type] = auxp; 670 } 671 672 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 673 if (binpath == NULL) { 674 aux_info[AT_EXECPATH] = NULL; 675 } else { 676 if (aux_info[AT_EXECPATH] == NULL) { 677 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 678 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 679 } 680 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 681 binpath); 682 } 683 } else { 684 _rtld_error("No binary"); 685 rtld_die(); 686 } 687 } 688 } 689 690 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 691 692 /* 693 * If the process is tainted, then we un-set the dangerous environment 694 * variables. The process will be marked as tainted until setuid(2) 695 * is called. If any child process calls setuid(2) we do not want any 696 * future processes to honor the potentially un-safe variables. 697 */ 698 if (!trust) { 699 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 700 lvd = &ld_env_vars[i]; 701 if (lvd->unsecure) 702 lvd->val = NULL; 703 } 704 } 705 706 ld_debug = ld_get_env_var(LD_DEBUG); 707 if (ld_bind_now == NULL) 708 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 709 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 710 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 711 libmap_override = ld_get_env_var(LD_LIBMAP); 712 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 713 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 714 ld_preload = ld_get_env_var(LD_PRELOAD); 715 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 716 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 717 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 718 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 719 if (library_path_rpath != NULL) { 720 if (library_path_rpath[0] == 'y' || 721 library_path_rpath[0] == 'Y' || 722 library_path_rpath[0] == '1') 723 ld_library_path_rpath = true; 724 else 725 ld_library_path_rpath = false; 726 } 727 dangerous_ld_env = libmap_disable || libmap_override != NULL || 728 ld_library_path != NULL || ld_preload != NULL || 729 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 730 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 731 ld_utrace = ld_get_env_var(LD_UTRACE); 732 733 set_ld_elf_hints_path(); 734 if (ld_debug != NULL && *ld_debug != '\0') 735 debug = 1; 736 dbg("%s is initialized, base address = %p", __progname, 737 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 738 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 739 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 740 741 dbg("initializing thread locks"); 742 lockdflt_init(); 743 744 /* 745 * Load the main program, or process its program header if it is 746 * already loaded. 747 */ 748 if (fd != -1) { /* Load the main program. */ 749 dbg("loading main program"); 750 obj_main = map_object(fd, argv0, NULL); 751 close(fd); 752 if (obj_main == NULL) 753 rtld_die(); 754 max_stack_flags = obj_main->stack_flags; 755 } else { /* Main program already loaded. */ 756 dbg("processing main program's program header"); 757 assert(aux_info[AT_PHDR] != NULL); 758 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 759 assert(aux_info[AT_PHNUM] != NULL); 760 phnum = aux_info[AT_PHNUM]->a_un.a_val; 761 assert(aux_info[AT_PHENT] != NULL); 762 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 763 assert(aux_info[AT_ENTRY] != NULL); 764 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 765 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 766 rtld_die(); 767 } 768 769 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 770 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 771 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 772 if (kexecpath[0] == '/') 773 obj_main->path = kexecpath; 774 else if (getcwd(buf, sizeof(buf)) == NULL || 775 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 776 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 777 obj_main->path = xstrdup(argv0); 778 else 779 obj_main->path = xstrdup(buf); 780 } else { 781 dbg("No AT_EXECPATH or direct exec"); 782 obj_main->path = xstrdup(argv0); 783 } 784 dbg("obj_main path %s", obj_main->path); 785 obj_main->mainprog = true; 786 787 if (aux_info[AT_STACKPROT] != NULL && 788 aux_info[AT_STACKPROT]->a_un.a_val != 0) 789 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 790 791 #ifndef COMPAT_32BIT 792 /* 793 * Get the actual dynamic linker pathname from the executable if 794 * possible. (It should always be possible.) That ensures that 795 * gdb will find the right dynamic linker even if a non-standard 796 * one is being used. 797 */ 798 if (obj_main->interp != NULL && 799 strcmp(obj_main->interp, obj_rtld.path) != 0) { 800 free(obj_rtld.path); 801 obj_rtld.path = xstrdup(obj_main->interp); 802 __progname = obj_rtld.path; 803 } 804 #endif 805 806 if (!digest_dynamic(obj_main, 0)) 807 rtld_die(); 808 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 809 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 810 obj_main->dynsymcount); 811 812 linkmap_add(obj_main); 813 linkmap_add(&obj_rtld); 814 815 /* Link the main program into the list of objects. */ 816 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 817 obj_count++; 818 obj_loads++; 819 820 /* Initialize a fake symbol for resolving undefined weak references. */ 821 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 822 sym_zero.st_shndx = SHN_UNDEF; 823 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 824 825 if (!libmap_disable) 826 libmap_disable = (bool)lm_init(libmap_override); 827 828 dbg("loading LD_PRELOAD_FDS libraries"); 829 if (load_preload_objects(ld_preload_fds, true) == -1) 830 rtld_die(); 831 832 dbg("loading LD_PRELOAD libraries"); 833 if (load_preload_objects(ld_preload, false) == -1) 834 rtld_die(); 835 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 836 837 dbg("loading needed objects"); 838 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 839 0) == -1) 840 rtld_die(); 841 842 /* Make a list of all objects loaded at startup. */ 843 last_interposer = obj_main; 844 TAILQ_FOREACH(obj, &obj_list, next) { 845 if (obj->marker) 846 continue; 847 if (obj->z_interpose && obj != obj_main) { 848 objlist_put_after(&list_main, last_interposer, obj); 849 last_interposer = obj; 850 } else { 851 objlist_push_tail(&list_main, obj); 852 } 853 obj->refcount++; 854 } 855 856 dbg("checking for required versions"); 857 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 858 rtld_die(); 859 860 if (ld_tracing) { /* We're done */ 861 trace_loaded_objects(obj_main); 862 exit(0); 863 } 864 865 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 866 dump_relocations(obj_main); 867 exit (0); 868 } 869 870 /* 871 * Processing tls relocations requires having the tls offsets 872 * initialized. Prepare offsets before starting initial 873 * relocation processing. 874 */ 875 dbg("initializing initial thread local storage offsets"); 876 STAILQ_FOREACH(entry, &list_main, link) { 877 /* 878 * Allocate all the initial objects out of the static TLS 879 * block even if they didn't ask for it. 880 */ 881 allocate_tls_offset(entry->obj); 882 } 883 884 if (relocate_objects(obj_main, 885 ld_bind_now != NULL && *ld_bind_now != '\0', 886 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 887 rtld_die(); 888 889 dbg("doing copy relocations"); 890 if (do_copy_relocations(obj_main) == -1) 891 rtld_die(); 892 893 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 894 dump_relocations(obj_main); 895 exit (0); 896 } 897 898 ifunc_init(aux); 899 900 /* 901 * Setup TLS for main thread. This must be done after the 902 * relocations are processed, since tls initialization section 903 * might be the subject for relocations. 904 */ 905 dbg("initializing initial thread local storage"); 906 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 907 908 dbg("initializing key program variables"); 909 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 910 set_program_var("environ", env); 911 set_program_var("__elf_aux_vector", aux); 912 913 /* Make a list of init functions to call. */ 914 objlist_init(&initlist); 915 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 916 preload_tail, &initlist); 917 918 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 919 920 map_stacks_exec(NULL); 921 922 if (!obj_main->crt_no_init) { 923 /* 924 * Make sure we don't call the main program's init and fini 925 * functions for binaries linked with old crt1 which calls 926 * _init itself. 927 */ 928 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 929 obj_main->preinit_array = obj_main->init_array = 930 obj_main->fini_array = (Elf_Addr)NULL; 931 } 932 933 if (direct_exec) { 934 /* Set osrel for direct-execed binary */ 935 mib[0] = CTL_KERN; 936 mib[1] = KERN_PROC; 937 mib[2] = KERN_PROC_OSREL; 938 mib[3] = getpid(); 939 osrel = obj_main->osrel; 940 sz = sizeof(old_osrel); 941 dbg("setting osrel to %d", osrel); 942 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 943 } 944 945 wlock_acquire(rtld_bind_lock, &lockstate); 946 947 dbg("resolving ifuncs"); 948 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 949 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 950 rtld_die(); 951 952 rtld_exit_ptr = rtld_exit; 953 if (obj_main->crt_no_init) 954 preinit_main(); 955 objlist_call_init(&initlist, &lockstate); 956 _r_debug_postinit(&obj_main->linkmap); 957 objlist_clear(&initlist); 958 dbg("loading filtees"); 959 TAILQ_FOREACH(obj, &obj_list, next) { 960 if (obj->marker) 961 continue; 962 if (ld_loadfltr || obj->z_loadfltr) 963 load_filtees(obj, 0, &lockstate); 964 } 965 966 dbg("enforcing main obj relro"); 967 if (obj_enforce_relro(obj_main) == -1) 968 rtld_die(); 969 970 lock_release(rtld_bind_lock, &lockstate); 971 972 dbg("transferring control to program entry point = %p", obj_main->entry); 973 974 /* Return the exit procedure and the program entry point. */ 975 *exit_proc = rtld_exit_ptr; 976 *objp = obj_main; 977 return (func_ptr_type) obj_main->entry; 978 } 979 980 void * 981 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 982 { 983 void *ptr; 984 Elf_Addr target; 985 986 ptr = (void *)make_function_pointer(def, obj); 987 target = call_ifunc_resolver(ptr); 988 return ((void *)target); 989 } 990 991 /* 992 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 993 * Changes to this function should be applied there as well. 994 */ 995 Elf_Addr 996 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 997 { 998 const Elf_Rel *rel; 999 const Elf_Sym *def; 1000 const Obj_Entry *defobj; 1001 Elf_Addr *where; 1002 Elf_Addr target; 1003 RtldLockState lockstate; 1004 1005 rlock_acquire(rtld_bind_lock, &lockstate); 1006 if (sigsetjmp(lockstate.env, 0) != 0) 1007 lock_upgrade(rtld_bind_lock, &lockstate); 1008 if (obj->pltrel) 1009 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1010 else 1011 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1012 1013 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1014 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1015 NULL, &lockstate); 1016 if (def == NULL) 1017 rtld_die(); 1018 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1019 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1020 else 1021 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1022 1023 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1024 defobj->strtab + def->st_name, 1025 obj->path == NULL ? NULL : basename(obj->path), 1026 (void *)target, 1027 defobj->path == NULL ? NULL : basename(defobj->path)); 1028 1029 /* 1030 * Write the new contents for the jmpslot. Note that depending on 1031 * architecture, the value which we need to return back to the 1032 * lazy binding trampoline may or may not be the target 1033 * address. The value returned from reloc_jmpslot() is the value 1034 * that the trampoline needs. 1035 */ 1036 target = reloc_jmpslot(where, target, defobj, obj, rel); 1037 lock_release(rtld_bind_lock, &lockstate); 1038 return target; 1039 } 1040 1041 /* 1042 * Error reporting function. Use it like printf. If formats the message 1043 * into a buffer, and sets things up so that the next call to dlerror() 1044 * will return the message. 1045 */ 1046 void 1047 _rtld_error(const char *fmt, ...) 1048 { 1049 va_list ap; 1050 1051 va_start(ap, fmt); 1052 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1053 fmt, ap); 1054 va_end(ap); 1055 *lockinfo.dlerror_seen() = 0; 1056 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1057 } 1058 1059 /* 1060 * Return a dynamically-allocated copy of the current error message, if any. 1061 */ 1062 static struct dlerror_save * 1063 errmsg_save(void) 1064 { 1065 struct dlerror_save *res; 1066 1067 res = xmalloc(sizeof(*res)); 1068 res->seen = *lockinfo.dlerror_seen(); 1069 if (res->seen == 0) 1070 res->msg = xstrdup(lockinfo.dlerror_loc()); 1071 return (res); 1072 } 1073 1074 /* 1075 * Restore the current error message from a copy which was previously saved 1076 * by errmsg_save(). The copy is freed. 1077 */ 1078 static void 1079 errmsg_restore(struct dlerror_save *saved_msg) 1080 { 1081 if (saved_msg == NULL || saved_msg->seen == 1) { 1082 *lockinfo.dlerror_seen() = 1; 1083 } else { 1084 *lockinfo.dlerror_seen() = 0; 1085 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1086 lockinfo.dlerror_loc_sz); 1087 free(saved_msg->msg); 1088 } 1089 free(saved_msg); 1090 } 1091 1092 static const char * 1093 basename(const char *name) 1094 { 1095 const char *p = strrchr(name, '/'); 1096 return p != NULL ? p + 1 : name; 1097 } 1098 1099 static struct utsname uts; 1100 1101 static char * 1102 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1103 const char *subst, bool may_free) 1104 { 1105 char *p, *p1, *res, *resp; 1106 int subst_len, kw_len, subst_count, old_len, new_len; 1107 1108 kw_len = strlen(kw); 1109 1110 /* 1111 * First, count the number of the keyword occurrences, to 1112 * preallocate the final string. 1113 */ 1114 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1115 p1 = strstr(p, kw); 1116 if (p1 == NULL) 1117 break; 1118 } 1119 1120 /* 1121 * If the keyword is not found, just return. 1122 * 1123 * Return non-substituted string if resolution failed. We 1124 * cannot do anything more reasonable, the failure mode of the 1125 * caller is unresolved library anyway. 1126 */ 1127 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1128 return (may_free ? real : xstrdup(real)); 1129 if (obj != NULL) 1130 subst = obj->origin_path; 1131 1132 /* 1133 * There is indeed something to substitute. Calculate the 1134 * length of the resulting string, and allocate it. 1135 */ 1136 subst_len = strlen(subst); 1137 old_len = strlen(real); 1138 new_len = old_len + (subst_len - kw_len) * subst_count; 1139 res = xmalloc(new_len + 1); 1140 1141 /* 1142 * Now, execute the substitution loop. 1143 */ 1144 for (p = real, resp = res, *resp = '\0';;) { 1145 p1 = strstr(p, kw); 1146 if (p1 != NULL) { 1147 /* Copy the prefix before keyword. */ 1148 memcpy(resp, p, p1 - p); 1149 resp += p1 - p; 1150 /* Keyword replacement. */ 1151 memcpy(resp, subst, subst_len); 1152 resp += subst_len; 1153 *resp = '\0'; 1154 p = p1 + kw_len; 1155 } else 1156 break; 1157 } 1158 1159 /* Copy to the end of string and finish. */ 1160 strcat(resp, p); 1161 if (may_free) 1162 free(real); 1163 return (res); 1164 } 1165 1166 static char * 1167 origin_subst(Obj_Entry *obj, const char *real) 1168 { 1169 char *res1, *res2, *res3, *res4; 1170 1171 if (obj == NULL || !trust) 1172 return (xstrdup(real)); 1173 if (uts.sysname[0] == '\0') { 1174 if (uname(&uts) != 0) { 1175 _rtld_error("utsname failed: %d", errno); 1176 return (NULL); 1177 } 1178 } 1179 /* __DECONST is safe here since without may_free real is unchanged */ 1180 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1181 false); 1182 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1183 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1184 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1185 return (res4); 1186 } 1187 1188 void 1189 rtld_die(void) 1190 { 1191 const char *msg = dlerror(); 1192 1193 if (msg == NULL) 1194 msg = "Fatal error"; 1195 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1196 rtld_fdputstr(STDERR_FILENO, msg); 1197 rtld_fdputchar(STDERR_FILENO, '\n'); 1198 _exit(1); 1199 } 1200 1201 /* 1202 * Process a shared object's DYNAMIC section, and save the important 1203 * information in its Obj_Entry structure. 1204 */ 1205 static void 1206 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1207 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1208 { 1209 const Elf_Dyn *dynp; 1210 Needed_Entry **needed_tail = &obj->needed; 1211 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1212 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1213 const Elf_Hashelt *hashtab; 1214 const Elf32_Word *hashval; 1215 Elf32_Word bkt, nmaskwords; 1216 int bloom_size32; 1217 int plttype = DT_REL; 1218 1219 *dyn_rpath = NULL; 1220 *dyn_soname = NULL; 1221 *dyn_runpath = NULL; 1222 1223 obj->bind_now = false; 1224 dynp = obj->dynamic; 1225 if (dynp == NULL) 1226 return; 1227 for (; dynp->d_tag != DT_NULL; dynp++) { 1228 switch (dynp->d_tag) { 1229 1230 case DT_REL: 1231 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1232 break; 1233 1234 case DT_RELSZ: 1235 obj->relsize = dynp->d_un.d_val; 1236 break; 1237 1238 case DT_RELENT: 1239 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1240 break; 1241 1242 case DT_JMPREL: 1243 obj->pltrel = (const Elf_Rel *) 1244 (obj->relocbase + dynp->d_un.d_ptr); 1245 break; 1246 1247 case DT_PLTRELSZ: 1248 obj->pltrelsize = dynp->d_un.d_val; 1249 break; 1250 1251 case DT_RELA: 1252 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1253 break; 1254 1255 case DT_RELASZ: 1256 obj->relasize = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_RELAENT: 1260 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1261 break; 1262 1263 case DT_RELR: 1264 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1265 break; 1266 1267 case DT_RELRSZ: 1268 obj->relrsize = dynp->d_un.d_val; 1269 break; 1270 1271 case DT_RELRENT: 1272 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1273 break; 1274 1275 case DT_PLTREL: 1276 plttype = dynp->d_un.d_val; 1277 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1278 break; 1279 1280 case DT_SYMTAB: 1281 obj->symtab = (const Elf_Sym *) 1282 (obj->relocbase + dynp->d_un.d_ptr); 1283 break; 1284 1285 case DT_SYMENT: 1286 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1287 break; 1288 1289 case DT_STRTAB: 1290 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1291 break; 1292 1293 case DT_STRSZ: 1294 obj->strsize = dynp->d_un.d_val; 1295 break; 1296 1297 case DT_VERNEED: 1298 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1299 dynp->d_un.d_val); 1300 break; 1301 1302 case DT_VERNEEDNUM: 1303 obj->verneednum = dynp->d_un.d_val; 1304 break; 1305 1306 case DT_VERDEF: 1307 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1308 dynp->d_un.d_val); 1309 break; 1310 1311 case DT_VERDEFNUM: 1312 obj->verdefnum = dynp->d_un.d_val; 1313 break; 1314 1315 case DT_VERSYM: 1316 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1317 dynp->d_un.d_val); 1318 break; 1319 1320 case DT_HASH: 1321 { 1322 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1323 dynp->d_un.d_ptr); 1324 obj->nbuckets = hashtab[0]; 1325 obj->nchains = hashtab[1]; 1326 obj->buckets = hashtab + 2; 1327 obj->chains = obj->buckets + obj->nbuckets; 1328 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1329 obj->buckets != NULL; 1330 } 1331 break; 1332 1333 case DT_GNU_HASH: 1334 { 1335 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1336 dynp->d_un.d_ptr); 1337 obj->nbuckets_gnu = hashtab[0]; 1338 obj->symndx_gnu = hashtab[1]; 1339 nmaskwords = hashtab[2]; 1340 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1341 obj->maskwords_bm_gnu = nmaskwords - 1; 1342 obj->shift2_gnu = hashtab[3]; 1343 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1344 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1345 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1346 obj->symndx_gnu; 1347 /* Number of bitmask words is required to be power of 2 */ 1348 obj->valid_hash_gnu = powerof2(nmaskwords) && 1349 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1350 } 1351 break; 1352 1353 case DT_NEEDED: 1354 if (!obj->rtld) { 1355 Needed_Entry *nep = NEW(Needed_Entry); 1356 nep->name = dynp->d_un.d_val; 1357 nep->obj = NULL; 1358 nep->next = NULL; 1359 1360 *needed_tail = nep; 1361 needed_tail = &nep->next; 1362 } 1363 break; 1364 1365 case DT_FILTER: 1366 if (!obj->rtld) { 1367 Needed_Entry *nep = NEW(Needed_Entry); 1368 nep->name = dynp->d_un.d_val; 1369 nep->obj = NULL; 1370 nep->next = NULL; 1371 1372 *needed_filtees_tail = nep; 1373 needed_filtees_tail = &nep->next; 1374 1375 if (obj->linkmap.l_refname == NULL) 1376 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1377 } 1378 break; 1379 1380 case DT_AUXILIARY: 1381 if (!obj->rtld) { 1382 Needed_Entry *nep = NEW(Needed_Entry); 1383 nep->name = dynp->d_un.d_val; 1384 nep->obj = NULL; 1385 nep->next = NULL; 1386 1387 *needed_aux_filtees_tail = nep; 1388 needed_aux_filtees_tail = &nep->next; 1389 } 1390 break; 1391 1392 case DT_PLTGOT: 1393 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1394 break; 1395 1396 case DT_TEXTREL: 1397 obj->textrel = true; 1398 break; 1399 1400 case DT_SYMBOLIC: 1401 obj->symbolic = true; 1402 break; 1403 1404 case DT_RPATH: 1405 /* 1406 * We have to wait until later to process this, because we 1407 * might not have gotten the address of the string table yet. 1408 */ 1409 *dyn_rpath = dynp; 1410 break; 1411 1412 case DT_SONAME: 1413 *dyn_soname = dynp; 1414 break; 1415 1416 case DT_RUNPATH: 1417 *dyn_runpath = dynp; 1418 break; 1419 1420 case DT_INIT: 1421 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1422 break; 1423 1424 case DT_PREINIT_ARRAY: 1425 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1426 break; 1427 1428 case DT_PREINIT_ARRAYSZ: 1429 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1430 break; 1431 1432 case DT_INIT_ARRAY: 1433 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1434 break; 1435 1436 case DT_INIT_ARRAYSZ: 1437 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1438 break; 1439 1440 case DT_FINI: 1441 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1442 break; 1443 1444 case DT_FINI_ARRAY: 1445 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1446 break; 1447 1448 case DT_FINI_ARRAYSZ: 1449 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1450 break; 1451 1452 /* 1453 * Don't process DT_DEBUG on MIPS as the dynamic section 1454 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1455 */ 1456 1457 #ifndef __mips__ 1458 case DT_DEBUG: 1459 if (!early) 1460 dbg("Filling in DT_DEBUG entry"); 1461 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1462 break; 1463 #endif 1464 1465 case DT_FLAGS: 1466 if (dynp->d_un.d_val & DF_ORIGIN) 1467 obj->z_origin = true; 1468 if (dynp->d_un.d_val & DF_SYMBOLIC) 1469 obj->symbolic = true; 1470 if (dynp->d_un.d_val & DF_TEXTREL) 1471 obj->textrel = true; 1472 if (dynp->d_un.d_val & DF_BIND_NOW) 1473 obj->bind_now = true; 1474 if (dynp->d_un.d_val & DF_STATIC_TLS) 1475 obj->static_tls = true; 1476 break; 1477 #ifdef __mips__ 1478 case DT_MIPS_LOCAL_GOTNO: 1479 obj->local_gotno = dynp->d_un.d_val; 1480 break; 1481 1482 case DT_MIPS_SYMTABNO: 1483 obj->symtabno = dynp->d_un.d_val; 1484 break; 1485 1486 case DT_MIPS_GOTSYM: 1487 obj->gotsym = dynp->d_un.d_val; 1488 break; 1489 1490 case DT_MIPS_RLD_MAP: 1491 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1492 break; 1493 1494 case DT_MIPS_RLD_MAP_REL: 1495 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1496 // section relative to the address of the tag itself. 1497 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1498 (Elf_Addr) &r_debug; 1499 break; 1500 1501 case DT_MIPS_PLTGOT: 1502 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1503 dynp->d_un.d_ptr); 1504 break; 1505 1506 #endif 1507 1508 #ifdef __powerpc__ 1509 #ifdef __powerpc64__ 1510 case DT_PPC64_GLINK: 1511 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1512 break; 1513 #else 1514 case DT_PPC_GOT: 1515 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1516 break; 1517 #endif 1518 #endif 1519 1520 case DT_FLAGS_1: 1521 if (dynp->d_un.d_val & DF_1_NOOPEN) 1522 obj->z_noopen = true; 1523 if (dynp->d_un.d_val & DF_1_ORIGIN) 1524 obj->z_origin = true; 1525 if (dynp->d_un.d_val & DF_1_GLOBAL) 1526 obj->z_global = true; 1527 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1528 obj->bind_now = true; 1529 if (dynp->d_un.d_val & DF_1_NODELETE) 1530 obj->z_nodelete = true; 1531 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1532 obj->z_loadfltr = true; 1533 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1534 obj->z_interpose = true; 1535 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1536 obj->z_nodeflib = true; 1537 if (dynp->d_un.d_val & DF_1_PIE) 1538 obj->z_pie = true; 1539 break; 1540 1541 default: 1542 if (!early) { 1543 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1544 (long)dynp->d_tag); 1545 } 1546 break; 1547 } 1548 } 1549 1550 obj->traced = false; 1551 1552 if (plttype == DT_RELA) { 1553 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1554 obj->pltrel = NULL; 1555 obj->pltrelasize = obj->pltrelsize; 1556 obj->pltrelsize = 0; 1557 } 1558 1559 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1560 if (obj->valid_hash_sysv) 1561 obj->dynsymcount = obj->nchains; 1562 else if (obj->valid_hash_gnu) { 1563 obj->dynsymcount = 0; 1564 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1565 if (obj->buckets_gnu[bkt] == 0) 1566 continue; 1567 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1568 do 1569 obj->dynsymcount++; 1570 while ((*hashval++ & 1u) == 0); 1571 } 1572 obj->dynsymcount += obj->symndx_gnu; 1573 } 1574 1575 if (obj->linkmap.l_refname != NULL) 1576 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1577 linkmap.l_refname; 1578 } 1579 1580 static bool 1581 obj_resolve_origin(Obj_Entry *obj) 1582 { 1583 1584 if (obj->origin_path != NULL) 1585 return (true); 1586 obj->origin_path = xmalloc(PATH_MAX); 1587 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1588 } 1589 1590 static bool 1591 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1592 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1593 { 1594 1595 if (obj->z_origin && !obj_resolve_origin(obj)) 1596 return (false); 1597 1598 if (dyn_runpath != NULL) { 1599 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1600 obj->runpath = origin_subst(obj, obj->runpath); 1601 } else if (dyn_rpath != NULL) { 1602 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1603 obj->rpath = origin_subst(obj, obj->rpath); 1604 } 1605 if (dyn_soname != NULL) 1606 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1607 return (true); 1608 } 1609 1610 static bool 1611 digest_dynamic(Obj_Entry *obj, int early) 1612 { 1613 const Elf_Dyn *dyn_rpath; 1614 const Elf_Dyn *dyn_soname; 1615 const Elf_Dyn *dyn_runpath; 1616 1617 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1618 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1619 } 1620 1621 /* 1622 * Process a shared object's program header. This is used only for the 1623 * main program, when the kernel has already loaded the main program 1624 * into memory before calling the dynamic linker. It creates and 1625 * returns an Obj_Entry structure. 1626 */ 1627 static Obj_Entry * 1628 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1629 { 1630 Obj_Entry *obj; 1631 const Elf_Phdr *phlimit = phdr + phnum; 1632 const Elf_Phdr *ph; 1633 Elf_Addr note_start, note_end; 1634 int nsegs = 0; 1635 1636 obj = obj_new(); 1637 for (ph = phdr; ph < phlimit; ph++) { 1638 if (ph->p_type != PT_PHDR) 1639 continue; 1640 1641 obj->phdr = phdr; 1642 obj->phsize = ph->p_memsz; 1643 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1644 break; 1645 } 1646 1647 obj->stack_flags = PF_X | PF_R | PF_W; 1648 1649 for (ph = phdr; ph < phlimit; ph++) { 1650 switch (ph->p_type) { 1651 1652 case PT_INTERP: 1653 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1654 break; 1655 1656 case PT_LOAD: 1657 if (nsegs == 0) { /* First load segment */ 1658 obj->vaddrbase = trunc_page(ph->p_vaddr); 1659 obj->mapbase = obj->vaddrbase + obj->relocbase; 1660 } else { /* Last load segment */ 1661 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1662 obj->vaddrbase; 1663 } 1664 nsegs++; 1665 break; 1666 1667 case PT_DYNAMIC: 1668 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1669 break; 1670 1671 case PT_TLS: 1672 obj->tlsindex = 1; 1673 obj->tlssize = ph->p_memsz; 1674 obj->tlsalign = ph->p_align; 1675 obj->tlsinitsize = ph->p_filesz; 1676 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1677 obj->tlspoffset = ph->p_offset; 1678 break; 1679 1680 case PT_GNU_STACK: 1681 obj->stack_flags = ph->p_flags; 1682 break; 1683 1684 case PT_GNU_RELRO: 1685 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1686 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1687 trunc_page(ph->p_vaddr); 1688 break; 1689 1690 case PT_NOTE: 1691 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1692 note_end = note_start + ph->p_filesz; 1693 digest_notes(obj, note_start, note_end); 1694 break; 1695 } 1696 } 1697 if (nsegs < 1) { 1698 _rtld_error("%s: too few PT_LOAD segments", path); 1699 return NULL; 1700 } 1701 1702 obj->entry = entry; 1703 return obj; 1704 } 1705 1706 void 1707 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1708 { 1709 const Elf_Note *note; 1710 const char *note_name; 1711 uintptr_t p; 1712 1713 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1714 note = (const Elf_Note *)((const char *)(note + 1) + 1715 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1716 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1717 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1718 note->n_descsz != sizeof(int32_t)) 1719 continue; 1720 if (note->n_type != NT_FREEBSD_ABI_TAG && 1721 note->n_type != NT_FREEBSD_FEATURE_CTL && 1722 note->n_type != NT_FREEBSD_NOINIT_TAG) 1723 continue; 1724 note_name = (const char *)(note + 1); 1725 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1726 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1727 continue; 1728 switch (note->n_type) { 1729 case NT_FREEBSD_ABI_TAG: 1730 /* FreeBSD osrel note */ 1731 p = (uintptr_t)(note + 1); 1732 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1733 obj->osrel = *(const int32_t *)(p); 1734 dbg("note osrel %d", obj->osrel); 1735 break; 1736 case NT_FREEBSD_FEATURE_CTL: 1737 /* FreeBSD ABI feature control note */ 1738 p = (uintptr_t)(note + 1); 1739 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1740 obj->fctl0 = *(const uint32_t *)(p); 1741 dbg("note fctl0 %#x", obj->fctl0); 1742 break; 1743 case NT_FREEBSD_NOINIT_TAG: 1744 /* FreeBSD 'crt does not call init' note */ 1745 obj->crt_no_init = true; 1746 dbg("note crt_no_init"); 1747 break; 1748 } 1749 } 1750 } 1751 1752 static Obj_Entry * 1753 dlcheck(void *handle) 1754 { 1755 Obj_Entry *obj; 1756 1757 TAILQ_FOREACH(obj, &obj_list, next) { 1758 if (obj == (Obj_Entry *) handle) 1759 break; 1760 } 1761 1762 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1763 _rtld_error("Invalid shared object handle %p", handle); 1764 return NULL; 1765 } 1766 return obj; 1767 } 1768 1769 /* 1770 * If the given object is already in the donelist, return true. Otherwise 1771 * add the object to the list and return false. 1772 */ 1773 static bool 1774 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1775 { 1776 unsigned int i; 1777 1778 for (i = 0; i < dlp->num_used; i++) 1779 if (dlp->objs[i] == obj) 1780 return true; 1781 /* 1782 * Our donelist allocation should always be sufficient. But if 1783 * our threads locking isn't working properly, more shared objects 1784 * could have been loaded since we allocated the list. That should 1785 * never happen, but we'll handle it properly just in case it does. 1786 */ 1787 if (dlp->num_used < dlp->num_alloc) 1788 dlp->objs[dlp->num_used++] = obj; 1789 return false; 1790 } 1791 1792 /* 1793 * Hash function for symbol table lookup. Don't even think about changing 1794 * this. It is specified by the System V ABI. 1795 */ 1796 unsigned long 1797 elf_hash(const char *name) 1798 { 1799 const unsigned char *p = (const unsigned char *) name; 1800 unsigned long h = 0; 1801 unsigned long g; 1802 1803 while (*p != '\0') { 1804 h = (h << 4) + *p++; 1805 if ((g = h & 0xf0000000) != 0) 1806 h ^= g >> 24; 1807 h &= ~g; 1808 } 1809 return h; 1810 } 1811 1812 /* 1813 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1814 * unsigned in case it's implemented with a wider type. 1815 */ 1816 static uint32_t 1817 gnu_hash(const char *s) 1818 { 1819 uint32_t h; 1820 unsigned char c; 1821 1822 h = 5381; 1823 for (c = *s; c != '\0'; c = *++s) 1824 h = h * 33 + c; 1825 return (h & 0xffffffff); 1826 } 1827 1828 1829 /* 1830 * Find the library with the given name, and return its full pathname. 1831 * The returned string is dynamically allocated. Generates an error 1832 * message and returns NULL if the library cannot be found. 1833 * 1834 * If the second argument is non-NULL, then it refers to an already- 1835 * loaded shared object, whose library search path will be searched. 1836 * 1837 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1838 * descriptor (which is close-on-exec) will be passed out via the third 1839 * argument. 1840 * 1841 * The search order is: 1842 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1843 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1844 * LD_LIBRARY_PATH 1845 * DT_RUNPATH in the referencing file 1846 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1847 * from list) 1848 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1849 * 1850 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1851 */ 1852 static char * 1853 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1854 { 1855 char *pathname, *refobj_path; 1856 const char *name; 1857 bool nodeflib, objgiven; 1858 1859 objgiven = refobj != NULL; 1860 1861 if (libmap_disable || !objgiven || 1862 (name = lm_find(refobj->path, xname)) == NULL) 1863 name = xname; 1864 1865 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1866 if (name[0] != '/' && !trust) { 1867 _rtld_error("Absolute pathname required " 1868 "for shared object \"%s\"", name); 1869 return (NULL); 1870 } 1871 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1872 __DECONST(char *, name))); 1873 } 1874 1875 dbg(" Searching for \"%s\"", name); 1876 refobj_path = objgiven ? refobj->path : NULL; 1877 1878 /* 1879 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1880 * back to pre-conforming behaviour if user requested so with 1881 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1882 * nodeflib. 1883 */ 1884 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1885 pathname = search_library_path(name, ld_library_path, 1886 refobj_path, fdp); 1887 if (pathname != NULL) 1888 return (pathname); 1889 if (refobj != NULL) { 1890 pathname = search_library_path(name, refobj->rpath, 1891 refobj_path, fdp); 1892 if (pathname != NULL) 1893 return (pathname); 1894 } 1895 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1896 if (pathname != NULL) 1897 return (pathname); 1898 pathname = search_library_path(name, gethints(false), 1899 refobj_path, fdp); 1900 if (pathname != NULL) 1901 return (pathname); 1902 pathname = search_library_path(name, ld_standard_library_path, 1903 refobj_path, fdp); 1904 if (pathname != NULL) 1905 return (pathname); 1906 } else { 1907 nodeflib = objgiven ? refobj->z_nodeflib : false; 1908 if (objgiven) { 1909 pathname = search_library_path(name, refobj->rpath, 1910 refobj->path, fdp); 1911 if (pathname != NULL) 1912 return (pathname); 1913 } 1914 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1915 pathname = search_library_path(name, obj_main->rpath, 1916 refobj_path, fdp); 1917 if (pathname != NULL) 1918 return (pathname); 1919 } 1920 pathname = search_library_path(name, ld_library_path, 1921 refobj_path, fdp); 1922 if (pathname != NULL) 1923 return (pathname); 1924 if (objgiven) { 1925 pathname = search_library_path(name, refobj->runpath, 1926 refobj_path, fdp); 1927 if (pathname != NULL) 1928 return (pathname); 1929 } 1930 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1931 if (pathname != NULL) 1932 return (pathname); 1933 pathname = search_library_path(name, gethints(nodeflib), 1934 refobj_path, fdp); 1935 if (pathname != NULL) 1936 return (pathname); 1937 if (objgiven && !nodeflib) { 1938 pathname = search_library_path(name, 1939 ld_standard_library_path, refobj_path, fdp); 1940 if (pathname != NULL) 1941 return (pathname); 1942 } 1943 } 1944 1945 if (objgiven && refobj->path != NULL) { 1946 _rtld_error("Shared object \"%s\" not found, " 1947 "required by \"%s\"", name, basename(refobj->path)); 1948 } else { 1949 _rtld_error("Shared object \"%s\" not found", name); 1950 } 1951 return (NULL); 1952 } 1953 1954 /* 1955 * Given a symbol number in a referencing object, find the corresponding 1956 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1957 * no definition was found. Returns a pointer to the Obj_Entry of the 1958 * defining object via the reference parameter DEFOBJ_OUT. 1959 */ 1960 const Elf_Sym * 1961 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1962 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1963 RtldLockState *lockstate) 1964 { 1965 const Elf_Sym *ref; 1966 const Elf_Sym *def; 1967 const Obj_Entry *defobj; 1968 const Ver_Entry *ve; 1969 SymLook req; 1970 const char *name; 1971 int res; 1972 1973 /* 1974 * If we have already found this symbol, get the information from 1975 * the cache. 1976 */ 1977 if (symnum >= refobj->dynsymcount) 1978 return NULL; /* Bad object */ 1979 if (cache != NULL && cache[symnum].sym != NULL) { 1980 *defobj_out = cache[symnum].obj; 1981 return cache[symnum].sym; 1982 } 1983 1984 ref = refobj->symtab + symnum; 1985 name = refobj->strtab + ref->st_name; 1986 def = NULL; 1987 defobj = NULL; 1988 ve = NULL; 1989 1990 /* 1991 * We don't have to do a full scale lookup if the symbol is local. 1992 * We know it will bind to the instance in this load module; to 1993 * which we already have a pointer (ie ref). By not doing a lookup, 1994 * we not only improve performance, but it also avoids unresolvable 1995 * symbols when local symbols are not in the hash table. This has 1996 * been seen with the ia64 toolchain. 1997 */ 1998 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1999 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2000 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2001 symnum); 2002 } 2003 symlook_init(&req, name); 2004 req.flags = flags; 2005 ve = req.ventry = fetch_ventry(refobj, symnum); 2006 req.lockstate = lockstate; 2007 res = symlook_default(&req, refobj); 2008 if (res == 0) { 2009 def = req.sym_out; 2010 defobj = req.defobj_out; 2011 } 2012 } else { 2013 def = ref; 2014 defobj = refobj; 2015 } 2016 2017 /* 2018 * If we found no definition and the reference is weak, treat the 2019 * symbol as having the value zero. 2020 */ 2021 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2022 def = &sym_zero; 2023 defobj = obj_main; 2024 } 2025 2026 if (def != NULL) { 2027 *defobj_out = defobj; 2028 /* Record the information in the cache to avoid subsequent lookups. */ 2029 if (cache != NULL) { 2030 cache[symnum].sym = def; 2031 cache[symnum].obj = defobj; 2032 } 2033 } else { 2034 if (refobj != &obj_rtld) 2035 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2036 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2037 } 2038 return def; 2039 } 2040 2041 /* 2042 * Return the search path from the ldconfig hints file, reading it if 2043 * necessary. If nostdlib is true, then the default search paths are 2044 * not added to result. 2045 * 2046 * Returns NULL if there are problems with the hints file, 2047 * or if the search path there is empty. 2048 */ 2049 static const char * 2050 gethints(bool nostdlib) 2051 { 2052 static char *filtered_path; 2053 static const char *hints; 2054 static struct elfhints_hdr hdr; 2055 struct fill_search_info_args sargs, hargs; 2056 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2057 struct dl_serpath *SLPpath, *hintpath; 2058 char *p; 2059 struct stat hint_stat; 2060 unsigned int SLPndx, hintndx, fndx, fcount; 2061 int fd; 2062 size_t flen; 2063 uint32_t dl; 2064 bool skip; 2065 2066 /* First call, read the hints file */ 2067 if (hints == NULL) { 2068 /* Keep from trying again in case the hints file is bad. */ 2069 hints = ""; 2070 2071 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2072 return (NULL); 2073 2074 /* 2075 * Check of hdr.dirlistlen value against type limit 2076 * intends to pacify static analyzers. Further 2077 * paranoia leads to checks that dirlist is fully 2078 * contained in the file range. 2079 */ 2080 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2081 hdr.magic != ELFHINTS_MAGIC || 2082 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2083 fstat(fd, &hint_stat) == -1) { 2084 cleanup1: 2085 close(fd); 2086 hdr.dirlistlen = 0; 2087 return (NULL); 2088 } 2089 dl = hdr.strtab; 2090 if (dl + hdr.dirlist < dl) 2091 goto cleanup1; 2092 dl += hdr.dirlist; 2093 if (dl + hdr.dirlistlen < dl) 2094 goto cleanup1; 2095 dl += hdr.dirlistlen; 2096 if (dl > hint_stat.st_size) 2097 goto cleanup1; 2098 p = xmalloc(hdr.dirlistlen + 1); 2099 if (pread(fd, p, hdr.dirlistlen + 1, 2100 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2101 p[hdr.dirlistlen] != '\0') { 2102 free(p); 2103 goto cleanup1; 2104 } 2105 hints = p; 2106 close(fd); 2107 } 2108 2109 /* 2110 * If caller agreed to receive list which includes the default 2111 * paths, we are done. Otherwise, if we still did not 2112 * calculated filtered result, do it now. 2113 */ 2114 if (!nostdlib) 2115 return (hints[0] != '\0' ? hints : NULL); 2116 if (filtered_path != NULL) 2117 goto filt_ret; 2118 2119 /* 2120 * Obtain the list of all configured search paths, and the 2121 * list of the default paths. 2122 * 2123 * First estimate the size of the results. 2124 */ 2125 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2126 smeta.dls_cnt = 0; 2127 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2128 hmeta.dls_cnt = 0; 2129 2130 sargs.request = RTLD_DI_SERINFOSIZE; 2131 sargs.serinfo = &smeta; 2132 hargs.request = RTLD_DI_SERINFOSIZE; 2133 hargs.serinfo = &hmeta; 2134 2135 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2136 &sargs); 2137 path_enumerate(hints, fill_search_info, NULL, &hargs); 2138 2139 SLPinfo = xmalloc(smeta.dls_size); 2140 hintinfo = xmalloc(hmeta.dls_size); 2141 2142 /* 2143 * Next fetch both sets of paths. 2144 */ 2145 sargs.request = RTLD_DI_SERINFO; 2146 sargs.serinfo = SLPinfo; 2147 sargs.serpath = &SLPinfo->dls_serpath[0]; 2148 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2149 2150 hargs.request = RTLD_DI_SERINFO; 2151 hargs.serinfo = hintinfo; 2152 hargs.serpath = &hintinfo->dls_serpath[0]; 2153 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2154 2155 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2156 &sargs); 2157 path_enumerate(hints, fill_search_info, NULL, &hargs); 2158 2159 /* 2160 * Now calculate the difference between two sets, by excluding 2161 * standard paths from the full set. 2162 */ 2163 fndx = 0; 2164 fcount = 0; 2165 filtered_path = xmalloc(hdr.dirlistlen + 1); 2166 hintpath = &hintinfo->dls_serpath[0]; 2167 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2168 skip = false; 2169 SLPpath = &SLPinfo->dls_serpath[0]; 2170 /* 2171 * Check each standard path against current. 2172 */ 2173 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2174 /* matched, skip the path */ 2175 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2176 skip = true; 2177 break; 2178 } 2179 } 2180 if (skip) 2181 continue; 2182 /* 2183 * Not matched against any standard path, add the path 2184 * to result. Separate consequtive paths with ':'. 2185 */ 2186 if (fcount > 0) { 2187 filtered_path[fndx] = ':'; 2188 fndx++; 2189 } 2190 fcount++; 2191 flen = strlen(hintpath->dls_name); 2192 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2193 fndx += flen; 2194 } 2195 filtered_path[fndx] = '\0'; 2196 2197 free(SLPinfo); 2198 free(hintinfo); 2199 2200 filt_ret: 2201 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2202 } 2203 2204 static void 2205 init_dag(Obj_Entry *root) 2206 { 2207 const Needed_Entry *needed; 2208 const Objlist_Entry *elm; 2209 DoneList donelist; 2210 2211 if (root->dag_inited) 2212 return; 2213 donelist_init(&donelist); 2214 2215 /* Root object belongs to own DAG. */ 2216 objlist_push_tail(&root->dldags, root); 2217 objlist_push_tail(&root->dagmembers, root); 2218 donelist_check(&donelist, root); 2219 2220 /* 2221 * Add dependencies of root object to DAG in breadth order 2222 * by exploiting the fact that each new object get added 2223 * to the tail of the dagmembers list. 2224 */ 2225 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2226 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2227 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2228 continue; 2229 objlist_push_tail(&needed->obj->dldags, root); 2230 objlist_push_tail(&root->dagmembers, needed->obj); 2231 } 2232 } 2233 root->dag_inited = true; 2234 } 2235 2236 static void 2237 init_marker(Obj_Entry *marker) 2238 { 2239 2240 bzero(marker, sizeof(*marker)); 2241 marker->marker = true; 2242 } 2243 2244 Obj_Entry * 2245 globallist_curr(const Obj_Entry *obj) 2246 { 2247 2248 for (;;) { 2249 if (obj == NULL) 2250 return (NULL); 2251 if (!obj->marker) 2252 return (__DECONST(Obj_Entry *, obj)); 2253 obj = TAILQ_PREV(obj, obj_entry_q, next); 2254 } 2255 } 2256 2257 Obj_Entry * 2258 globallist_next(const Obj_Entry *obj) 2259 { 2260 2261 for (;;) { 2262 obj = TAILQ_NEXT(obj, next); 2263 if (obj == NULL) 2264 return (NULL); 2265 if (!obj->marker) 2266 return (__DECONST(Obj_Entry *, obj)); 2267 } 2268 } 2269 2270 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2271 static void 2272 hold_object(Obj_Entry *obj) 2273 { 2274 2275 obj->holdcount++; 2276 } 2277 2278 static void 2279 unhold_object(Obj_Entry *obj) 2280 { 2281 2282 assert(obj->holdcount > 0); 2283 if (--obj->holdcount == 0 && obj->unholdfree) 2284 release_object(obj); 2285 } 2286 2287 static void 2288 process_z(Obj_Entry *root) 2289 { 2290 const Objlist_Entry *elm; 2291 Obj_Entry *obj; 2292 2293 /* 2294 * Walk over object DAG and process every dependent object 2295 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2296 * to grow their own DAG. 2297 * 2298 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2299 * symlook_global() to work. 2300 * 2301 * For DF_1_NODELETE, the DAG should have its reference upped. 2302 */ 2303 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2304 obj = elm->obj; 2305 if (obj == NULL) 2306 continue; 2307 if (obj->z_nodelete && !obj->ref_nodel) { 2308 dbg("obj %s -z nodelete", obj->path); 2309 init_dag(obj); 2310 ref_dag(obj); 2311 obj->ref_nodel = true; 2312 } 2313 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2314 dbg("obj %s -z global", obj->path); 2315 objlist_push_tail(&list_global, obj); 2316 init_dag(obj); 2317 } 2318 } 2319 } 2320 2321 static void 2322 parse_rtld_phdr(Obj_Entry *obj) 2323 { 2324 const Elf_Phdr *ph; 2325 Elf_Addr note_start, note_end; 2326 2327 obj->stack_flags = PF_X | PF_R | PF_W; 2328 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2329 obj->phsize; ph++) { 2330 switch (ph->p_type) { 2331 case PT_GNU_STACK: 2332 obj->stack_flags = ph->p_flags; 2333 break; 2334 case PT_GNU_RELRO: 2335 obj->relro_page = obj->relocbase + 2336 trunc_page(ph->p_vaddr); 2337 obj->relro_size = round_page(ph->p_memsz); 2338 break; 2339 case PT_NOTE: 2340 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2341 note_end = note_start + ph->p_filesz; 2342 digest_notes(obj, note_start, note_end); 2343 break; 2344 } 2345 } 2346 } 2347 2348 /* 2349 * Initialize the dynamic linker. The argument is the address at which 2350 * the dynamic linker has been mapped into memory. The primary task of 2351 * this function is to relocate the dynamic linker. 2352 */ 2353 static void 2354 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2355 { 2356 Obj_Entry objtmp; /* Temporary rtld object */ 2357 const Elf_Ehdr *ehdr; 2358 const Elf_Dyn *dyn_rpath; 2359 const Elf_Dyn *dyn_soname; 2360 const Elf_Dyn *dyn_runpath; 2361 2362 #ifdef RTLD_INIT_PAGESIZES_EARLY 2363 /* The page size is required by the dynamic memory allocator. */ 2364 init_pagesizes(aux_info); 2365 #endif 2366 2367 /* 2368 * Conjure up an Obj_Entry structure for the dynamic linker. 2369 * 2370 * The "path" member can't be initialized yet because string constants 2371 * cannot yet be accessed. Below we will set it correctly. 2372 */ 2373 memset(&objtmp, 0, sizeof(objtmp)); 2374 objtmp.path = NULL; 2375 objtmp.rtld = true; 2376 objtmp.mapbase = mapbase; 2377 #ifdef PIC 2378 objtmp.relocbase = mapbase; 2379 #endif 2380 2381 objtmp.dynamic = rtld_dynamic(&objtmp); 2382 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2383 assert(objtmp.needed == NULL); 2384 #if !defined(__mips__) 2385 /* MIPS has a bogus DT_TEXTREL. */ 2386 assert(!objtmp.textrel); 2387 #endif 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 2471 /* 2472 * Add the init functions from a needed object list (and its recursive 2473 * needed objects) to "list". This is not used directly; it is a helper 2474 * function for initlist_add_objects(). The write lock must be held 2475 * when this function is called. 2476 */ 2477 static void 2478 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2479 { 2480 /* Recursively process the successor needed objects. */ 2481 if (needed->next != NULL) 2482 initlist_add_neededs(needed->next, list); 2483 2484 /* Process the current needed object. */ 2485 if (needed->obj != NULL) 2486 initlist_add_objects(needed->obj, needed->obj, list); 2487 } 2488 2489 /* 2490 * Scan all of the DAGs rooted in the range of objects from "obj" to 2491 * "tail" and add their init functions to "list". This recurses over 2492 * the DAGs and ensure the proper init ordering such that each object's 2493 * needed libraries are initialized before the object itself. At the 2494 * same time, this function adds the objects to the global finalization 2495 * list "list_fini" in the opposite order. The write lock must be 2496 * held when this function is called. 2497 */ 2498 static void 2499 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2500 { 2501 Obj_Entry *nobj; 2502 2503 if (obj->init_scanned || obj->init_done) 2504 return; 2505 obj->init_scanned = true; 2506 2507 /* Recursively process the successor objects. */ 2508 nobj = globallist_next(obj); 2509 if (nobj != NULL && obj != tail) 2510 initlist_add_objects(nobj, tail, list); 2511 2512 /* Recursively process the needed objects. */ 2513 if (obj->needed != NULL) 2514 initlist_add_neededs(obj->needed, list); 2515 if (obj->needed_filtees != NULL) 2516 initlist_add_neededs(obj->needed_filtees, list); 2517 if (obj->needed_aux_filtees != NULL) 2518 initlist_add_neededs(obj->needed_aux_filtees, list); 2519 2520 /* Add the object to the init list. */ 2521 objlist_push_tail(list, obj); 2522 2523 /* Add the object to the global fini list in the reverse order. */ 2524 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2525 && !obj->on_fini_list) { 2526 objlist_push_head(&list_fini, obj); 2527 obj->on_fini_list = true; 2528 } 2529 } 2530 2531 #ifndef FPTR_TARGET 2532 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2533 #endif 2534 2535 static void 2536 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2537 { 2538 Needed_Entry *needed, *needed1; 2539 2540 for (needed = n; needed != NULL; needed = needed->next) { 2541 if (needed->obj != NULL) { 2542 dlclose_locked(needed->obj, lockstate); 2543 needed->obj = NULL; 2544 } 2545 } 2546 for (needed = n; needed != NULL; needed = needed1) { 2547 needed1 = needed->next; 2548 free(needed); 2549 } 2550 } 2551 2552 static void 2553 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2554 { 2555 2556 free_needed_filtees(obj->needed_filtees, lockstate); 2557 obj->needed_filtees = NULL; 2558 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2559 obj->needed_aux_filtees = NULL; 2560 obj->filtees_loaded = false; 2561 } 2562 2563 static void 2564 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2565 RtldLockState *lockstate) 2566 { 2567 2568 for (; needed != NULL; needed = needed->next) { 2569 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2570 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2571 RTLD_LOCAL, lockstate); 2572 } 2573 } 2574 2575 static void 2576 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2577 { 2578 2579 lock_restart_for_upgrade(lockstate); 2580 if (!obj->filtees_loaded) { 2581 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2582 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2583 obj->filtees_loaded = true; 2584 } 2585 } 2586 2587 static int 2588 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2589 { 2590 Obj_Entry *obj1; 2591 2592 for (; needed != NULL; needed = needed->next) { 2593 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2594 flags & ~RTLD_LO_NOLOAD); 2595 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2596 return (-1); 2597 } 2598 return (0); 2599 } 2600 2601 /* 2602 * Given a shared object, traverse its list of needed objects, and load 2603 * each of them. Returns 0 on success. Generates an error message and 2604 * returns -1 on failure. 2605 */ 2606 static int 2607 load_needed_objects(Obj_Entry *first, int flags) 2608 { 2609 Obj_Entry *obj; 2610 2611 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2612 if (obj->marker) 2613 continue; 2614 if (process_needed(obj, obj->needed, flags) == -1) 2615 return (-1); 2616 } 2617 return (0); 2618 } 2619 2620 static int 2621 load_preload_objects(const char *penv, bool isfd) 2622 { 2623 Obj_Entry *obj; 2624 const char *name; 2625 size_t len; 2626 char savech, *p, *psave; 2627 int fd; 2628 static const char delim[] = " \t:;"; 2629 2630 if (penv == NULL) 2631 return (0); 2632 2633 p = psave = xstrdup(penv); 2634 p += strspn(p, delim); 2635 while (*p != '\0') { 2636 len = strcspn(p, delim); 2637 2638 savech = p[len]; 2639 p[len] = '\0'; 2640 if (isfd) { 2641 name = NULL; 2642 fd = parse_integer(p); 2643 if (fd == -1) { 2644 free(psave); 2645 return (-1); 2646 } 2647 } else { 2648 name = p; 2649 fd = -1; 2650 } 2651 2652 obj = load_object(name, fd, NULL, 0); 2653 if (obj == NULL) { 2654 free(psave); 2655 return (-1); /* XXX - cleanup */ 2656 } 2657 obj->z_interpose = true; 2658 p[len] = savech; 2659 p += len; 2660 p += strspn(p, delim); 2661 } 2662 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2663 2664 free(psave); 2665 return (0); 2666 } 2667 2668 static const char * 2669 printable_path(const char *path) 2670 { 2671 2672 return (path == NULL ? "<unknown>" : path); 2673 } 2674 2675 /* 2676 * Load a shared object into memory, if it is not already loaded. The 2677 * object may be specified by name or by user-supplied file descriptor 2678 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2679 * duplicate is. 2680 * 2681 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2682 * on failure. 2683 */ 2684 static Obj_Entry * 2685 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2686 { 2687 Obj_Entry *obj; 2688 int fd; 2689 struct stat sb; 2690 char *path; 2691 2692 fd = -1; 2693 if (name != NULL) { 2694 TAILQ_FOREACH(obj, &obj_list, next) { 2695 if (obj->marker || obj->doomed) 2696 continue; 2697 if (object_match_name(obj, name)) 2698 return (obj); 2699 } 2700 2701 path = find_library(name, refobj, &fd); 2702 if (path == NULL) 2703 return (NULL); 2704 } else 2705 path = NULL; 2706 2707 if (fd >= 0) { 2708 /* 2709 * search_library_pathfds() opens a fresh file descriptor for the 2710 * library, so there is no need to dup(). 2711 */ 2712 } else if (fd_u == -1) { 2713 /* 2714 * If we didn't find a match by pathname, or the name is not 2715 * supplied, open the file and check again by device and inode. 2716 * This avoids false mismatches caused by multiple links or ".." 2717 * in pathnames. 2718 * 2719 * To avoid a race, we open the file and use fstat() rather than 2720 * using stat(). 2721 */ 2722 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2723 _rtld_error("Cannot open \"%s\"", path); 2724 free(path); 2725 return (NULL); 2726 } 2727 } else { 2728 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2729 if (fd == -1) { 2730 _rtld_error("Cannot dup fd"); 2731 free(path); 2732 return (NULL); 2733 } 2734 } 2735 if (fstat(fd, &sb) == -1) { 2736 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2737 close(fd); 2738 free(path); 2739 return NULL; 2740 } 2741 TAILQ_FOREACH(obj, &obj_list, next) { 2742 if (obj->marker || obj->doomed) 2743 continue; 2744 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2745 break; 2746 } 2747 if (obj != NULL && name != NULL) { 2748 object_add_name(obj, name); 2749 free(path); 2750 close(fd); 2751 return obj; 2752 } 2753 if (flags & RTLD_LO_NOLOAD) { 2754 free(path); 2755 close(fd); 2756 return (NULL); 2757 } 2758 2759 /* First use of this object, so we must map it in */ 2760 obj = do_load_object(fd, name, path, &sb, flags); 2761 if (obj == NULL) 2762 free(path); 2763 close(fd); 2764 2765 return obj; 2766 } 2767 2768 static Obj_Entry * 2769 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2770 int flags) 2771 { 2772 Obj_Entry *obj; 2773 struct statfs fs; 2774 2775 /* 2776 * First, make sure that environment variables haven't been 2777 * used to circumvent the noexec flag on a filesystem. 2778 * We ignore fstatfs(2) failures, since fd might reference 2779 * not a file, e.g. shmfd. 2780 */ 2781 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2782 (fs.f_flags & MNT_NOEXEC) != 0) { 2783 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2784 return (NULL); 2785 } 2786 2787 dbg("loading \"%s\"", printable_path(path)); 2788 obj = map_object(fd, printable_path(path), sbp); 2789 if (obj == NULL) 2790 return NULL; 2791 2792 /* 2793 * If DT_SONAME is present in the object, digest_dynamic2 already 2794 * added it to the object names. 2795 */ 2796 if (name != NULL) 2797 object_add_name(obj, name); 2798 obj->path = path; 2799 if (!digest_dynamic(obj, 0)) 2800 goto errp; 2801 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2802 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2803 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2804 dbg("refusing to load PIE executable \"%s\"", obj->path); 2805 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2806 goto errp; 2807 } 2808 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2809 RTLD_LO_DLOPEN) { 2810 dbg("refusing to load non-loadable \"%s\"", obj->path); 2811 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2812 goto errp; 2813 } 2814 2815 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2816 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2817 obj_count++; 2818 obj_loads++; 2819 linkmap_add(obj); /* for GDB & dlinfo() */ 2820 max_stack_flags |= obj->stack_flags; 2821 2822 dbg(" %p .. %p: %s", obj->mapbase, 2823 obj->mapbase + obj->mapsize - 1, obj->path); 2824 if (obj->textrel) 2825 dbg(" WARNING: %s has impure text", obj->path); 2826 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2827 obj->path); 2828 2829 return (obj); 2830 2831 errp: 2832 munmap(obj->mapbase, obj->mapsize); 2833 obj_free(obj); 2834 return (NULL); 2835 } 2836 2837 Obj_Entry * 2838 obj_from_addr(const void *addr) 2839 { 2840 Obj_Entry *obj; 2841 2842 TAILQ_FOREACH(obj, &obj_list, next) { 2843 if (obj->marker) 2844 continue; 2845 if (addr < (void *) obj->mapbase) 2846 continue; 2847 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2848 return obj; 2849 } 2850 return NULL; 2851 } 2852 2853 static void 2854 preinit_main(void) 2855 { 2856 Elf_Addr *preinit_addr; 2857 int index; 2858 2859 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2860 if (preinit_addr == NULL) 2861 return; 2862 2863 for (index = 0; index < obj_main->preinit_array_num; index++) { 2864 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2865 dbg("calling preinit function for %s at %p", obj_main->path, 2866 (void *)preinit_addr[index]); 2867 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2868 0, 0, obj_main->path); 2869 call_init_pointer(obj_main, preinit_addr[index]); 2870 } 2871 } 2872 } 2873 2874 /* 2875 * Call the finalization functions for each of the objects in "list" 2876 * belonging to the DAG of "root" and referenced once. If NULL "root" 2877 * is specified, every finalization function will be called regardless 2878 * of the reference count and the list elements won't be freed. All of 2879 * the objects are expected to have non-NULL fini functions. 2880 */ 2881 static void 2882 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2883 { 2884 Objlist_Entry *elm; 2885 struct dlerror_save *saved_msg; 2886 Elf_Addr *fini_addr; 2887 int index; 2888 2889 assert(root == NULL || root->refcount == 1); 2890 2891 if (root != NULL) 2892 root->doomed = true; 2893 2894 /* 2895 * Preserve the current error message since a fini function might 2896 * call into the dynamic linker and overwrite it. 2897 */ 2898 saved_msg = errmsg_save(); 2899 do { 2900 STAILQ_FOREACH(elm, list, link) { 2901 if (root != NULL && (elm->obj->refcount != 1 || 2902 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2903 continue; 2904 /* Remove object from fini list to prevent recursive invocation. */ 2905 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2906 /* Ensure that new references cannot be acquired. */ 2907 elm->obj->doomed = true; 2908 2909 hold_object(elm->obj); 2910 lock_release(rtld_bind_lock, lockstate); 2911 /* 2912 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2913 * When this happens, DT_FINI_ARRAY is processed first. 2914 */ 2915 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2916 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2917 for (index = elm->obj->fini_array_num - 1; index >= 0; 2918 index--) { 2919 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2920 dbg("calling fini function for %s at %p", 2921 elm->obj->path, (void *)fini_addr[index]); 2922 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2923 (void *)fini_addr[index], 0, 0, elm->obj->path); 2924 call_initfini_pointer(elm->obj, fini_addr[index]); 2925 } 2926 } 2927 } 2928 if (elm->obj->fini != (Elf_Addr)NULL) { 2929 dbg("calling fini function for %s at %p", elm->obj->path, 2930 (void *)elm->obj->fini); 2931 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2932 0, 0, elm->obj->path); 2933 call_initfini_pointer(elm->obj, elm->obj->fini); 2934 } 2935 wlock_acquire(rtld_bind_lock, lockstate); 2936 unhold_object(elm->obj); 2937 /* No need to free anything if process is going down. */ 2938 if (root != NULL) 2939 free(elm); 2940 /* 2941 * We must restart the list traversal after every fini call 2942 * because a dlclose() call from the fini function or from 2943 * another thread might have modified the reference counts. 2944 */ 2945 break; 2946 } 2947 } while (elm != NULL); 2948 errmsg_restore(saved_msg); 2949 } 2950 2951 /* 2952 * Call the initialization functions for each of the objects in 2953 * "list". All of the objects are expected to have non-NULL init 2954 * functions. 2955 */ 2956 static void 2957 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2958 { 2959 Objlist_Entry *elm; 2960 Obj_Entry *obj; 2961 struct dlerror_save *saved_msg; 2962 Elf_Addr *init_addr; 2963 void (*reg)(void (*)(void)); 2964 int index; 2965 2966 /* 2967 * Clean init_scanned flag so that objects can be rechecked and 2968 * possibly initialized earlier if any of vectors called below 2969 * cause the change by using dlopen. 2970 */ 2971 TAILQ_FOREACH(obj, &obj_list, next) { 2972 if (obj->marker) 2973 continue; 2974 obj->init_scanned = false; 2975 } 2976 2977 /* 2978 * Preserve the current error message since an init function might 2979 * call into the dynamic linker and overwrite it. 2980 */ 2981 saved_msg = errmsg_save(); 2982 STAILQ_FOREACH(elm, list, link) { 2983 if (elm->obj->init_done) /* Initialized early. */ 2984 continue; 2985 /* 2986 * Race: other thread might try to use this object before current 2987 * one completes the initialization. Not much can be done here 2988 * without better locking. 2989 */ 2990 elm->obj->init_done = true; 2991 hold_object(elm->obj); 2992 reg = NULL; 2993 if (elm->obj == obj_main && obj_main->crt_no_init) { 2994 reg = (void (*)(void (*)(void)))get_program_var_addr( 2995 "__libc_atexit", lockstate); 2996 } 2997 lock_release(rtld_bind_lock, lockstate); 2998 if (reg != NULL) { 2999 reg(rtld_exit); 3000 rtld_exit_ptr = rtld_nop_exit; 3001 } 3002 3003 /* 3004 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3005 * When this happens, DT_INIT is processed first. 3006 */ 3007 if (elm->obj->init != (Elf_Addr)NULL) { 3008 dbg("calling init function for %s at %p", elm->obj->path, 3009 (void *)elm->obj->init); 3010 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3011 0, 0, elm->obj->path); 3012 call_init_pointer(elm->obj, elm->obj->init); 3013 } 3014 init_addr = (Elf_Addr *)elm->obj->init_array; 3015 if (init_addr != NULL) { 3016 for (index = 0; index < elm->obj->init_array_num; index++) { 3017 if (init_addr[index] != 0 && init_addr[index] != 1) { 3018 dbg("calling init function for %s at %p", elm->obj->path, 3019 (void *)init_addr[index]); 3020 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3021 (void *)init_addr[index], 0, 0, elm->obj->path); 3022 call_init_pointer(elm->obj, init_addr[index]); 3023 } 3024 } 3025 } 3026 wlock_acquire(rtld_bind_lock, lockstate); 3027 unhold_object(elm->obj); 3028 } 3029 errmsg_restore(saved_msg); 3030 } 3031 3032 static void 3033 objlist_clear(Objlist *list) 3034 { 3035 Objlist_Entry *elm; 3036 3037 while (!STAILQ_EMPTY(list)) { 3038 elm = STAILQ_FIRST(list); 3039 STAILQ_REMOVE_HEAD(list, link); 3040 free(elm); 3041 } 3042 } 3043 3044 static Objlist_Entry * 3045 objlist_find(Objlist *list, const Obj_Entry *obj) 3046 { 3047 Objlist_Entry *elm; 3048 3049 STAILQ_FOREACH(elm, list, link) 3050 if (elm->obj == obj) 3051 return elm; 3052 return NULL; 3053 } 3054 3055 static void 3056 objlist_init(Objlist *list) 3057 { 3058 STAILQ_INIT(list); 3059 } 3060 3061 static void 3062 objlist_push_head(Objlist *list, Obj_Entry *obj) 3063 { 3064 Objlist_Entry *elm; 3065 3066 elm = NEW(Objlist_Entry); 3067 elm->obj = obj; 3068 STAILQ_INSERT_HEAD(list, elm, link); 3069 } 3070 3071 static void 3072 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3073 { 3074 Objlist_Entry *elm; 3075 3076 elm = NEW(Objlist_Entry); 3077 elm->obj = obj; 3078 STAILQ_INSERT_TAIL(list, elm, link); 3079 } 3080 3081 static void 3082 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3083 { 3084 Objlist_Entry *elm, *listelm; 3085 3086 STAILQ_FOREACH(listelm, list, link) { 3087 if (listelm->obj == listobj) 3088 break; 3089 } 3090 elm = NEW(Objlist_Entry); 3091 elm->obj = obj; 3092 if (listelm != NULL) 3093 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3094 else 3095 STAILQ_INSERT_TAIL(list, elm, link); 3096 } 3097 3098 static void 3099 objlist_remove(Objlist *list, Obj_Entry *obj) 3100 { 3101 Objlist_Entry *elm; 3102 3103 if ((elm = objlist_find(list, obj)) != NULL) { 3104 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3105 free(elm); 3106 } 3107 } 3108 3109 /* 3110 * Relocate dag rooted in the specified object. 3111 * Returns 0 on success, or -1 on failure. 3112 */ 3113 3114 static int 3115 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3116 int flags, RtldLockState *lockstate) 3117 { 3118 Objlist_Entry *elm; 3119 int error; 3120 3121 error = 0; 3122 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3123 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3124 lockstate); 3125 if (error == -1) 3126 break; 3127 } 3128 return (error); 3129 } 3130 3131 /* 3132 * Prepare for, or clean after, relocating an object marked with 3133 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3134 * segments are remapped read-write. After relocations are done, the 3135 * segment's permissions are returned back to the modes specified in 3136 * the phdrs. If any relocation happened, or always for wired 3137 * program, COW is triggered. 3138 */ 3139 static int 3140 reloc_textrel_prot(Obj_Entry *obj, bool before) 3141 { 3142 const Elf_Phdr *ph; 3143 void *base; 3144 size_t l, sz; 3145 int prot; 3146 3147 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3148 l--, ph++) { 3149 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3150 continue; 3151 base = obj->relocbase + trunc_page(ph->p_vaddr); 3152 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3153 trunc_page(ph->p_vaddr); 3154 prot = before ? (PROT_READ | PROT_WRITE) : 3155 convert_prot(ph->p_flags); 3156 if (mprotect(base, sz, prot) == -1) { 3157 _rtld_error("%s: Cannot write-%sable text segment: %s", 3158 obj->path, before ? "en" : "dis", 3159 rtld_strerror(errno)); 3160 return (-1); 3161 } 3162 } 3163 return (0); 3164 } 3165 3166 /* Process RELR relative relocations. */ 3167 static void 3168 reloc_relr(Obj_Entry *obj) 3169 { 3170 const Elf_Relr *relr, *relrlim; 3171 Elf_Addr *where; 3172 3173 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3174 for (relr = obj->relr; relr < relrlim; relr++) { 3175 Elf_Relr entry = *relr; 3176 3177 if ((entry & 1) == 0) { 3178 where = (Elf_Addr *)(obj->relocbase + entry); 3179 *where++ += (Elf_Addr)obj->relocbase; 3180 } else { 3181 for (long i = 0; (entry >>= 1) != 0; i++) 3182 if ((entry & 1) != 0) 3183 where[i] += (Elf_Addr)obj->relocbase; 3184 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3185 } 3186 } 3187 } 3188 3189 /* 3190 * Relocate single object. 3191 * Returns 0 on success, or -1 on failure. 3192 */ 3193 static int 3194 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3195 int flags, RtldLockState *lockstate) 3196 { 3197 3198 if (obj->relocated) 3199 return (0); 3200 obj->relocated = true; 3201 if (obj != rtldobj) 3202 dbg("relocating \"%s\"", obj->path); 3203 3204 if (obj->symtab == NULL || obj->strtab == NULL || 3205 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3206 dbg("object %s has no run-time symbol table", obj->path); 3207 3208 /* There are relocations to the write-protected text segment. */ 3209 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3210 return (-1); 3211 3212 /* Process the non-PLT non-IFUNC relocations. */ 3213 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3214 return (-1); 3215 reloc_relr(obj); 3216 3217 /* Re-protected the text segment. */ 3218 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3219 return (-1); 3220 3221 /* Set the special PLT or GOT entries. */ 3222 init_pltgot(obj); 3223 3224 /* Process the PLT relocations. */ 3225 if (reloc_plt(obj, flags, lockstate) == -1) 3226 return (-1); 3227 /* Relocate the jump slots if we are doing immediate binding. */ 3228 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3229 lockstate) == -1) 3230 return (-1); 3231 3232 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3233 return (-1); 3234 3235 /* 3236 * Set up the magic number and version in the Obj_Entry. These 3237 * were checked in the crt1.o from the original ElfKit, so we 3238 * set them for backward compatibility. 3239 */ 3240 obj->magic = RTLD_MAGIC; 3241 obj->version = RTLD_VERSION; 3242 3243 return (0); 3244 } 3245 3246 /* 3247 * Relocate newly-loaded shared objects. The argument is a pointer to 3248 * the Obj_Entry for the first such object. All objects from the first 3249 * to the end of the list of objects are relocated. Returns 0 on success, 3250 * or -1 on failure. 3251 */ 3252 static int 3253 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3254 int flags, RtldLockState *lockstate) 3255 { 3256 Obj_Entry *obj; 3257 int error; 3258 3259 for (error = 0, obj = first; obj != NULL; 3260 obj = TAILQ_NEXT(obj, next)) { 3261 if (obj->marker) 3262 continue; 3263 error = relocate_object(obj, bind_now, rtldobj, flags, 3264 lockstate); 3265 if (error == -1) 3266 break; 3267 } 3268 return (error); 3269 } 3270 3271 /* 3272 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3273 * referencing STT_GNU_IFUNC symbols is postponed till the other 3274 * relocations are done. The indirect functions specified as 3275 * ifunc are allowed to call other symbols, so we need to have 3276 * objects relocated before asking for resolution from indirects. 3277 * 3278 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3279 * instead of the usual lazy handling of PLT slots. It is 3280 * consistent with how GNU does it. 3281 */ 3282 static int 3283 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3284 RtldLockState *lockstate) 3285 { 3286 3287 if (obj->ifuncs_resolved) 3288 return (0); 3289 obj->ifuncs_resolved = true; 3290 if (!obj->irelative && !obj->irelative_nonplt && 3291 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3292 !obj->non_plt_gnu_ifunc) 3293 return (0); 3294 if (obj_disable_relro(obj) == -1 || 3295 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3296 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3297 lockstate) == -1) || 3298 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3299 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3300 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3301 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3302 obj_enforce_relro(obj) == -1) 3303 return (-1); 3304 return (0); 3305 } 3306 3307 static int 3308 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3309 RtldLockState *lockstate) 3310 { 3311 Objlist_Entry *elm; 3312 Obj_Entry *obj; 3313 3314 STAILQ_FOREACH(elm, list, link) { 3315 obj = elm->obj; 3316 if (obj->marker) 3317 continue; 3318 if (resolve_object_ifunc(obj, bind_now, flags, 3319 lockstate) == -1) 3320 return (-1); 3321 } 3322 return (0); 3323 } 3324 3325 /* 3326 * Cleanup procedure. It will be called (by the atexit mechanism) just 3327 * before the process exits. 3328 */ 3329 static void 3330 rtld_exit(void) 3331 { 3332 RtldLockState lockstate; 3333 3334 wlock_acquire(rtld_bind_lock, &lockstate); 3335 dbg("rtld_exit()"); 3336 objlist_call_fini(&list_fini, NULL, &lockstate); 3337 /* No need to remove the items from the list, since we are exiting. */ 3338 if (!libmap_disable) 3339 lm_fini(); 3340 lock_release(rtld_bind_lock, &lockstate); 3341 } 3342 3343 static void 3344 rtld_nop_exit(void) 3345 { 3346 } 3347 3348 /* 3349 * Iterate over a search path, translate each element, and invoke the 3350 * callback on the result. 3351 */ 3352 static void * 3353 path_enumerate(const char *path, path_enum_proc callback, 3354 const char *refobj_path, void *arg) 3355 { 3356 const char *trans; 3357 if (path == NULL) 3358 return (NULL); 3359 3360 path += strspn(path, ":;"); 3361 while (*path != '\0') { 3362 size_t len; 3363 char *res; 3364 3365 len = strcspn(path, ":;"); 3366 trans = lm_findn(refobj_path, path, len); 3367 if (trans) 3368 res = callback(trans, strlen(trans), arg); 3369 else 3370 res = callback(path, len, arg); 3371 3372 if (res != NULL) 3373 return (res); 3374 3375 path += len; 3376 path += strspn(path, ":;"); 3377 } 3378 3379 return (NULL); 3380 } 3381 3382 struct try_library_args { 3383 const char *name; 3384 size_t namelen; 3385 char *buffer; 3386 size_t buflen; 3387 int fd; 3388 }; 3389 3390 static void * 3391 try_library_path(const char *dir, size_t dirlen, void *param) 3392 { 3393 struct try_library_args *arg; 3394 int fd; 3395 3396 arg = param; 3397 if (*dir == '/' || trust) { 3398 char *pathname; 3399 3400 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3401 return (NULL); 3402 3403 pathname = arg->buffer; 3404 strncpy(pathname, dir, dirlen); 3405 pathname[dirlen] = '/'; 3406 strcpy(pathname + dirlen + 1, arg->name); 3407 3408 dbg(" Trying \"%s\"", pathname); 3409 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3410 if (fd >= 0) { 3411 dbg(" Opened \"%s\", fd %d", pathname, fd); 3412 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3413 strcpy(pathname, arg->buffer); 3414 arg->fd = fd; 3415 return (pathname); 3416 } else { 3417 dbg(" Failed to open \"%s\": %s", 3418 pathname, rtld_strerror(errno)); 3419 } 3420 } 3421 return (NULL); 3422 } 3423 3424 static char * 3425 search_library_path(const char *name, const char *path, 3426 const char *refobj_path, int *fdp) 3427 { 3428 char *p; 3429 struct try_library_args arg; 3430 3431 if (path == NULL) 3432 return NULL; 3433 3434 arg.name = name; 3435 arg.namelen = strlen(name); 3436 arg.buffer = xmalloc(PATH_MAX); 3437 arg.buflen = PATH_MAX; 3438 arg.fd = -1; 3439 3440 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3441 *fdp = arg.fd; 3442 3443 free(arg.buffer); 3444 3445 return (p); 3446 } 3447 3448 3449 /* 3450 * Finds the library with the given name using the directory descriptors 3451 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3452 * 3453 * Returns a freshly-opened close-on-exec file descriptor for the library, 3454 * or -1 if the library cannot be found. 3455 */ 3456 static char * 3457 search_library_pathfds(const char *name, const char *path, int *fdp) 3458 { 3459 char *envcopy, *fdstr, *found, *last_token; 3460 size_t len; 3461 int dirfd, fd; 3462 3463 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3464 3465 /* Don't load from user-specified libdirs into setuid binaries. */ 3466 if (!trust) 3467 return (NULL); 3468 3469 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3470 if (path == NULL) 3471 return (NULL); 3472 3473 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3474 if (name[0] == '/') { 3475 dbg("Absolute path (%s) passed to %s", name, __func__); 3476 return (NULL); 3477 } 3478 3479 /* 3480 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3481 * copy of the path, as strtok_r rewrites separator tokens 3482 * with '\0'. 3483 */ 3484 found = NULL; 3485 envcopy = xstrdup(path); 3486 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3487 fdstr = strtok_r(NULL, ":", &last_token)) { 3488 dirfd = parse_integer(fdstr); 3489 if (dirfd < 0) { 3490 _rtld_error("failed to parse directory FD: '%s'", 3491 fdstr); 3492 break; 3493 } 3494 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3495 if (fd >= 0) { 3496 *fdp = fd; 3497 len = strlen(fdstr) + strlen(name) + 3; 3498 found = xmalloc(len); 3499 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3500 _rtld_error("error generating '%d/%s'", 3501 dirfd, name); 3502 rtld_die(); 3503 } 3504 dbg("open('%s') => %d", found, fd); 3505 break; 3506 } 3507 } 3508 free(envcopy); 3509 3510 return (found); 3511 } 3512 3513 3514 int 3515 dlclose(void *handle) 3516 { 3517 RtldLockState lockstate; 3518 int error; 3519 3520 wlock_acquire(rtld_bind_lock, &lockstate); 3521 error = dlclose_locked(handle, &lockstate); 3522 lock_release(rtld_bind_lock, &lockstate); 3523 return (error); 3524 } 3525 3526 static int 3527 dlclose_locked(void *handle, RtldLockState *lockstate) 3528 { 3529 Obj_Entry *root; 3530 3531 root = dlcheck(handle); 3532 if (root == NULL) 3533 return -1; 3534 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3535 root->path); 3536 3537 /* Unreference the object and its dependencies. */ 3538 root->dl_refcount--; 3539 3540 if (root->refcount == 1) { 3541 /* 3542 * The object will be no longer referenced, so we must unload it. 3543 * First, call the fini functions. 3544 */ 3545 objlist_call_fini(&list_fini, root, lockstate); 3546 3547 unref_dag(root); 3548 3549 /* Finish cleaning up the newly-unreferenced objects. */ 3550 GDB_STATE(RT_DELETE,&root->linkmap); 3551 unload_object(root, lockstate); 3552 GDB_STATE(RT_CONSISTENT,NULL); 3553 } else 3554 unref_dag(root); 3555 3556 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3557 return 0; 3558 } 3559 3560 char * 3561 dlerror(void) 3562 { 3563 if (*(lockinfo.dlerror_seen()) != 0) 3564 return (NULL); 3565 *lockinfo.dlerror_seen() = 1; 3566 return (lockinfo.dlerror_loc()); 3567 } 3568 3569 /* 3570 * This function is deprecated and has no effect. 3571 */ 3572 void 3573 dllockinit(void *context, 3574 void *(*_lock_create)(void *context) __unused, 3575 void (*_rlock_acquire)(void *lock) __unused, 3576 void (*_wlock_acquire)(void *lock) __unused, 3577 void (*_lock_release)(void *lock) __unused, 3578 void (*_lock_destroy)(void *lock) __unused, 3579 void (*context_destroy)(void *context)) 3580 { 3581 static void *cur_context; 3582 static void (*cur_context_destroy)(void *); 3583 3584 /* Just destroy the context from the previous call, if necessary. */ 3585 if (cur_context_destroy != NULL) 3586 cur_context_destroy(cur_context); 3587 cur_context = context; 3588 cur_context_destroy = context_destroy; 3589 } 3590 3591 void * 3592 dlopen(const char *name, int mode) 3593 { 3594 3595 return (rtld_dlopen(name, -1, mode)); 3596 } 3597 3598 void * 3599 fdlopen(int fd, int mode) 3600 { 3601 3602 return (rtld_dlopen(NULL, fd, mode)); 3603 } 3604 3605 static void * 3606 rtld_dlopen(const char *name, int fd, int mode) 3607 { 3608 RtldLockState lockstate; 3609 int lo_flags; 3610 3611 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3612 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3613 if (ld_tracing != NULL) { 3614 rlock_acquire(rtld_bind_lock, &lockstate); 3615 if (sigsetjmp(lockstate.env, 0) != 0) 3616 lock_upgrade(rtld_bind_lock, &lockstate); 3617 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3618 lock_release(rtld_bind_lock, &lockstate); 3619 } 3620 lo_flags = RTLD_LO_DLOPEN; 3621 if (mode & RTLD_NODELETE) 3622 lo_flags |= RTLD_LO_NODELETE; 3623 if (mode & RTLD_NOLOAD) 3624 lo_flags |= RTLD_LO_NOLOAD; 3625 if (mode & RTLD_DEEPBIND) 3626 lo_flags |= RTLD_LO_DEEPBIND; 3627 if (ld_tracing != NULL) 3628 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3629 3630 return (dlopen_object(name, fd, obj_main, lo_flags, 3631 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3632 } 3633 3634 static void 3635 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3636 { 3637 3638 obj->dl_refcount--; 3639 unref_dag(obj); 3640 if (obj->refcount == 0) 3641 unload_object(obj, lockstate); 3642 } 3643 3644 static Obj_Entry * 3645 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3646 int mode, RtldLockState *lockstate) 3647 { 3648 Obj_Entry *old_obj_tail; 3649 Obj_Entry *obj; 3650 Objlist initlist; 3651 RtldLockState mlockstate; 3652 int result; 3653 3654 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3655 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3656 refobj->path, lo_flags, mode); 3657 objlist_init(&initlist); 3658 3659 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3660 wlock_acquire(rtld_bind_lock, &mlockstate); 3661 lockstate = &mlockstate; 3662 } 3663 GDB_STATE(RT_ADD,NULL); 3664 3665 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3666 obj = NULL; 3667 if (name == NULL && fd == -1) { 3668 obj = obj_main; 3669 obj->refcount++; 3670 } else { 3671 obj = load_object(name, fd, refobj, lo_flags); 3672 } 3673 3674 if (obj) { 3675 obj->dl_refcount++; 3676 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3677 objlist_push_tail(&list_global, obj); 3678 if (globallist_next(old_obj_tail) != NULL) { 3679 /* We loaded something new. */ 3680 assert(globallist_next(old_obj_tail) == obj); 3681 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3682 obj->symbolic = true; 3683 result = 0; 3684 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3685 obj->static_tls && !allocate_tls_offset(obj)) { 3686 _rtld_error("%s: No space available " 3687 "for static Thread Local Storage", obj->path); 3688 result = -1; 3689 } 3690 if (result != -1) 3691 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3692 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3693 init_dag(obj); 3694 ref_dag(obj); 3695 if (result != -1) 3696 result = rtld_verify_versions(&obj->dagmembers); 3697 if (result != -1 && ld_tracing) 3698 goto trace; 3699 if (result == -1 || relocate_object_dag(obj, 3700 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3701 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3702 lockstate) == -1) { 3703 dlopen_cleanup(obj, lockstate); 3704 obj = NULL; 3705 } else if (lo_flags & RTLD_LO_EARLY) { 3706 /* 3707 * Do not call the init functions for early loaded 3708 * filtees. The image is still not initialized enough 3709 * for them to work. 3710 * 3711 * Our object is found by the global object list and 3712 * will be ordered among all init calls done right 3713 * before transferring control to main. 3714 */ 3715 } else { 3716 /* Make list of init functions to call. */ 3717 initlist_add_objects(obj, obj, &initlist); 3718 } 3719 /* 3720 * Process all no_delete or global objects here, given 3721 * them own DAGs to prevent their dependencies from being 3722 * unloaded. This has to be done after we have loaded all 3723 * of the dependencies, so that we do not miss any. 3724 */ 3725 if (obj != NULL) 3726 process_z(obj); 3727 } else { 3728 /* 3729 * Bump the reference counts for objects on this DAG. If 3730 * this is the first dlopen() call for the object that was 3731 * already loaded as a dependency, initialize the dag 3732 * starting at it. 3733 */ 3734 init_dag(obj); 3735 ref_dag(obj); 3736 3737 if ((lo_flags & RTLD_LO_TRACE) != 0) 3738 goto trace; 3739 } 3740 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3741 obj->z_nodelete) && !obj->ref_nodel) { 3742 dbg("obj %s nodelete", obj->path); 3743 ref_dag(obj); 3744 obj->z_nodelete = obj->ref_nodel = true; 3745 } 3746 } 3747 3748 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3749 name); 3750 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3751 3752 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3753 map_stacks_exec(lockstate); 3754 if (obj != NULL) 3755 distribute_static_tls(&initlist, lockstate); 3756 } 3757 3758 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3759 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3760 lockstate) == -1) { 3761 objlist_clear(&initlist); 3762 dlopen_cleanup(obj, lockstate); 3763 if (lockstate == &mlockstate) 3764 lock_release(rtld_bind_lock, lockstate); 3765 return (NULL); 3766 } 3767 3768 if (!(lo_flags & RTLD_LO_EARLY)) { 3769 /* Call the init functions. */ 3770 objlist_call_init(&initlist, lockstate); 3771 } 3772 objlist_clear(&initlist); 3773 if (lockstate == &mlockstate) 3774 lock_release(rtld_bind_lock, lockstate); 3775 return obj; 3776 trace: 3777 trace_loaded_objects(obj); 3778 if (lockstate == &mlockstate) 3779 lock_release(rtld_bind_lock, lockstate); 3780 exit(0); 3781 } 3782 3783 static void * 3784 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3785 int flags) 3786 { 3787 DoneList donelist; 3788 const Obj_Entry *obj, *defobj; 3789 const Elf_Sym *def; 3790 SymLook req; 3791 RtldLockState lockstate; 3792 tls_index ti; 3793 void *sym; 3794 int res; 3795 3796 def = NULL; 3797 defobj = NULL; 3798 symlook_init(&req, name); 3799 req.ventry = ve; 3800 req.flags = flags | SYMLOOK_IN_PLT; 3801 req.lockstate = &lockstate; 3802 3803 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3804 rlock_acquire(rtld_bind_lock, &lockstate); 3805 if (sigsetjmp(lockstate.env, 0) != 0) 3806 lock_upgrade(rtld_bind_lock, &lockstate); 3807 if (handle == NULL || handle == RTLD_NEXT || 3808 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3809 3810 if ((obj = obj_from_addr(retaddr)) == NULL) { 3811 _rtld_error("Cannot determine caller's shared object"); 3812 lock_release(rtld_bind_lock, &lockstate); 3813 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3814 return NULL; 3815 } 3816 if (handle == NULL) { /* Just the caller's shared object. */ 3817 res = symlook_obj(&req, obj); 3818 if (res == 0) { 3819 def = req.sym_out; 3820 defobj = req.defobj_out; 3821 } 3822 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3823 handle == RTLD_SELF) { /* ... caller included */ 3824 if (handle == RTLD_NEXT) 3825 obj = globallist_next(obj); 3826 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3827 if (obj->marker) 3828 continue; 3829 res = symlook_obj(&req, obj); 3830 if (res == 0) { 3831 if (def == NULL || (ld_dynamic_weak && 3832 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3833 def = req.sym_out; 3834 defobj = req.defobj_out; 3835 if (!ld_dynamic_weak || 3836 ELF_ST_BIND(def->st_info) != STB_WEAK) 3837 break; 3838 } 3839 } 3840 } 3841 /* 3842 * Search the dynamic linker itself, and possibly resolve the 3843 * symbol from there. This is how the application links to 3844 * dynamic linker services such as dlopen. 3845 * Note that we ignore ld_dynamic_weak == false case, 3846 * always overriding weak symbols by rtld definitions. 3847 */ 3848 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3849 res = symlook_obj(&req, &obj_rtld); 3850 if (res == 0) { 3851 def = req.sym_out; 3852 defobj = req.defobj_out; 3853 } 3854 } 3855 } else { 3856 assert(handle == RTLD_DEFAULT); 3857 res = symlook_default(&req, obj); 3858 if (res == 0) { 3859 defobj = req.defobj_out; 3860 def = req.sym_out; 3861 } 3862 } 3863 } else { 3864 if ((obj = dlcheck(handle)) == NULL) { 3865 lock_release(rtld_bind_lock, &lockstate); 3866 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3867 return NULL; 3868 } 3869 3870 donelist_init(&donelist); 3871 if (obj->mainprog) { 3872 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3873 res = symlook_global(&req, &donelist); 3874 if (res == 0) { 3875 def = req.sym_out; 3876 defobj = req.defobj_out; 3877 } 3878 /* 3879 * Search the dynamic linker itself, and possibly resolve the 3880 * symbol from there. This is how the application links to 3881 * dynamic linker services such as dlopen. 3882 */ 3883 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3884 res = symlook_obj(&req, &obj_rtld); 3885 if (res == 0) { 3886 def = req.sym_out; 3887 defobj = req.defobj_out; 3888 } 3889 } 3890 } 3891 else { 3892 /* Search the whole DAG rooted at the given object. */ 3893 res = symlook_list(&req, &obj->dagmembers, &donelist); 3894 if (res == 0) { 3895 def = req.sym_out; 3896 defobj = req.defobj_out; 3897 } 3898 } 3899 } 3900 3901 if (def != NULL) { 3902 lock_release(rtld_bind_lock, &lockstate); 3903 3904 /* 3905 * The value required by the caller is derived from the value 3906 * of the symbol. this is simply the relocated value of the 3907 * symbol. 3908 */ 3909 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3910 sym = make_function_pointer(def, defobj); 3911 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3912 sym = rtld_resolve_ifunc(defobj, def); 3913 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3914 ti.ti_module = defobj->tlsindex; 3915 ti.ti_offset = def->st_value; 3916 sym = __tls_get_addr(&ti); 3917 } else 3918 sym = defobj->relocbase + def->st_value; 3919 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3920 return (sym); 3921 } 3922 3923 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3924 ve != NULL ? ve->name : ""); 3925 lock_release(rtld_bind_lock, &lockstate); 3926 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3927 return NULL; 3928 } 3929 3930 void * 3931 dlsym(void *handle, const char *name) 3932 { 3933 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3934 SYMLOOK_DLSYM); 3935 } 3936 3937 dlfunc_t 3938 dlfunc(void *handle, const char *name) 3939 { 3940 union { 3941 void *d; 3942 dlfunc_t f; 3943 } rv; 3944 3945 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3946 SYMLOOK_DLSYM); 3947 return (rv.f); 3948 } 3949 3950 void * 3951 dlvsym(void *handle, const char *name, const char *version) 3952 { 3953 Ver_Entry ventry; 3954 3955 ventry.name = version; 3956 ventry.file = NULL; 3957 ventry.hash = elf_hash(version); 3958 ventry.flags= 0; 3959 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3960 SYMLOOK_DLSYM); 3961 } 3962 3963 int 3964 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3965 { 3966 const Obj_Entry *obj; 3967 RtldLockState lockstate; 3968 3969 rlock_acquire(rtld_bind_lock, &lockstate); 3970 obj = obj_from_addr(addr); 3971 if (obj == NULL) { 3972 _rtld_error("No shared object contains address"); 3973 lock_release(rtld_bind_lock, &lockstate); 3974 return (0); 3975 } 3976 rtld_fill_dl_phdr_info(obj, phdr_info); 3977 lock_release(rtld_bind_lock, &lockstate); 3978 return (1); 3979 } 3980 3981 int 3982 dladdr(const void *addr, Dl_info *info) 3983 { 3984 const Obj_Entry *obj; 3985 const Elf_Sym *def; 3986 void *symbol_addr; 3987 unsigned long symoffset; 3988 RtldLockState lockstate; 3989 3990 rlock_acquire(rtld_bind_lock, &lockstate); 3991 obj = obj_from_addr(addr); 3992 if (obj == NULL) { 3993 _rtld_error("No shared object contains address"); 3994 lock_release(rtld_bind_lock, &lockstate); 3995 return 0; 3996 } 3997 info->dli_fname = obj->path; 3998 info->dli_fbase = obj->mapbase; 3999 info->dli_saddr = (void *)0; 4000 info->dli_sname = NULL; 4001 4002 /* 4003 * Walk the symbol list looking for the symbol whose address is 4004 * closest to the address sent in. 4005 */ 4006 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4007 def = obj->symtab + symoffset; 4008 4009 /* 4010 * For skip the symbol if st_shndx is either SHN_UNDEF or 4011 * SHN_COMMON. 4012 */ 4013 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4014 continue; 4015 4016 /* 4017 * If the symbol is greater than the specified address, or if it 4018 * is further away from addr than the current nearest symbol, 4019 * then reject it. 4020 */ 4021 symbol_addr = obj->relocbase + def->st_value; 4022 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4023 continue; 4024 4025 /* Update our idea of the nearest symbol. */ 4026 info->dli_sname = obj->strtab + def->st_name; 4027 info->dli_saddr = symbol_addr; 4028 4029 /* Exact match? */ 4030 if (info->dli_saddr == addr) 4031 break; 4032 } 4033 lock_release(rtld_bind_lock, &lockstate); 4034 return 1; 4035 } 4036 4037 int 4038 dlinfo(void *handle, int request, void *p) 4039 { 4040 const Obj_Entry *obj; 4041 RtldLockState lockstate; 4042 int error; 4043 4044 rlock_acquire(rtld_bind_lock, &lockstate); 4045 4046 if (handle == NULL || handle == RTLD_SELF) { 4047 void *retaddr; 4048 4049 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4050 if ((obj = obj_from_addr(retaddr)) == NULL) 4051 _rtld_error("Cannot determine caller's shared object"); 4052 } else 4053 obj = dlcheck(handle); 4054 4055 if (obj == NULL) { 4056 lock_release(rtld_bind_lock, &lockstate); 4057 return (-1); 4058 } 4059 4060 error = 0; 4061 switch (request) { 4062 case RTLD_DI_LINKMAP: 4063 *((struct link_map const **)p) = &obj->linkmap; 4064 break; 4065 case RTLD_DI_ORIGIN: 4066 error = rtld_dirname(obj->path, p); 4067 break; 4068 4069 case RTLD_DI_SERINFOSIZE: 4070 case RTLD_DI_SERINFO: 4071 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4072 break; 4073 4074 default: 4075 _rtld_error("Invalid request %d passed to dlinfo()", request); 4076 error = -1; 4077 } 4078 4079 lock_release(rtld_bind_lock, &lockstate); 4080 4081 return (error); 4082 } 4083 4084 static void 4085 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4086 { 4087 Elf_Addr **dtvp; 4088 4089 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4090 phdr_info->dlpi_name = obj->path; 4091 phdr_info->dlpi_phdr = obj->phdr; 4092 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4093 phdr_info->dlpi_tls_modid = obj->tlsindex; 4094 dtvp = _get_tp(); 4095 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4096 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4097 phdr_info->dlpi_adds = obj_loads; 4098 phdr_info->dlpi_subs = obj_loads - obj_count; 4099 } 4100 4101 int 4102 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4103 { 4104 struct dl_phdr_info phdr_info; 4105 Obj_Entry *obj, marker; 4106 RtldLockState bind_lockstate, phdr_lockstate; 4107 int error; 4108 4109 init_marker(&marker); 4110 error = 0; 4111 4112 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4113 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4114 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4115 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4116 rtld_fill_dl_phdr_info(obj, &phdr_info); 4117 hold_object(obj); 4118 lock_release(rtld_bind_lock, &bind_lockstate); 4119 4120 error = callback(&phdr_info, sizeof phdr_info, param); 4121 4122 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4123 unhold_object(obj); 4124 obj = globallist_next(&marker); 4125 TAILQ_REMOVE(&obj_list, &marker, next); 4126 if (error != 0) { 4127 lock_release(rtld_bind_lock, &bind_lockstate); 4128 lock_release(rtld_phdr_lock, &phdr_lockstate); 4129 return (error); 4130 } 4131 } 4132 4133 if (error == 0) { 4134 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4135 lock_release(rtld_bind_lock, &bind_lockstate); 4136 error = callback(&phdr_info, sizeof(phdr_info), param); 4137 } 4138 lock_release(rtld_phdr_lock, &phdr_lockstate); 4139 return (error); 4140 } 4141 4142 static void * 4143 fill_search_info(const char *dir, size_t dirlen, void *param) 4144 { 4145 struct fill_search_info_args *arg; 4146 4147 arg = param; 4148 4149 if (arg->request == RTLD_DI_SERINFOSIZE) { 4150 arg->serinfo->dls_cnt ++; 4151 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4152 } else { 4153 struct dl_serpath *s_entry; 4154 4155 s_entry = arg->serpath; 4156 s_entry->dls_name = arg->strspace; 4157 s_entry->dls_flags = arg->flags; 4158 4159 strncpy(arg->strspace, dir, dirlen); 4160 arg->strspace[dirlen] = '\0'; 4161 4162 arg->strspace += dirlen + 1; 4163 arg->serpath++; 4164 } 4165 4166 return (NULL); 4167 } 4168 4169 static int 4170 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4171 { 4172 struct dl_serinfo _info; 4173 struct fill_search_info_args args; 4174 4175 args.request = RTLD_DI_SERINFOSIZE; 4176 args.serinfo = &_info; 4177 4178 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4179 _info.dls_cnt = 0; 4180 4181 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4182 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4183 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4184 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4185 if (!obj->z_nodeflib) 4186 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4187 4188 4189 if (request == RTLD_DI_SERINFOSIZE) { 4190 info->dls_size = _info.dls_size; 4191 info->dls_cnt = _info.dls_cnt; 4192 return (0); 4193 } 4194 4195 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4196 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4197 return (-1); 4198 } 4199 4200 args.request = RTLD_DI_SERINFO; 4201 args.serinfo = info; 4202 args.serpath = &info->dls_serpath[0]; 4203 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4204 4205 args.flags = LA_SER_RUNPATH; 4206 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4207 return (-1); 4208 4209 args.flags = LA_SER_LIBPATH; 4210 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4211 return (-1); 4212 4213 args.flags = LA_SER_RUNPATH; 4214 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4215 return (-1); 4216 4217 args.flags = LA_SER_CONFIG; 4218 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4219 != NULL) 4220 return (-1); 4221 4222 args.flags = LA_SER_DEFAULT; 4223 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4224 fill_search_info, NULL, &args) != NULL) 4225 return (-1); 4226 return (0); 4227 } 4228 4229 static int 4230 rtld_dirname(const char *path, char *bname) 4231 { 4232 const char *endp; 4233 4234 /* Empty or NULL string gets treated as "." */ 4235 if (path == NULL || *path == '\0') { 4236 bname[0] = '.'; 4237 bname[1] = '\0'; 4238 return (0); 4239 } 4240 4241 /* Strip trailing slashes */ 4242 endp = path + strlen(path) - 1; 4243 while (endp > path && *endp == '/') 4244 endp--; 4245 4246 /* Find the start of the dir */ 4247 while (endp > path && *endp != '/') 4248 endp--; 4249 4250 /* Either the dir is "/" or there are no slashes */ 4251 if (endp == path) { 4252 bname[0] = *endp == '/' ? '/' : '.'; 4253 bname[1] = '\0'; 4254 return (0); 4255 } else { 4256 do { 4257 endp--; 4258 } while (endp > path && *endp == '/'); 4259 } 4260 4261 if (endp - path + 2 > PATH_MAX) 4262 { 4263 _rtld_error("Filename is too long: %s", path); 4264 return(-1); 4265 } 4266 4267 strncpy(bname, path, endp - path + 1); 4268 bname[endp - path + 1] = '\0'; 4269 return (0); 4270 } 4271 4272 static int 4273 rtld_dirname_abs(const char *path, char *base) 4274 { 4275 char *last; 4276 4277 if (realpath(path, base) == NULL) { 4278 _rtld_error("realpath \"%s\" failed (%s)", path, 4279 rtld_strerror(errno)); 4280 return (-1); 4281 } 4282 dbg("%s -> %s", path, base); 4283 last = strrchr(base, '/'); 4284 if (last == NULL) { 4285 _rtld_error("non-abs result from realpath \"%s\"", path); 4286 return (-1); 4287 } 4288 if (last != base) 4289 *last = '\0'; 4290 return (0); 4291 } 4292 4293 static void 4294 linkmap_add(Obj_Entry *obj) 4295 { 4296 struct link_map *l, *prev; 4297 4298 l = &obj->linkmap; 4299 l->l_name = obj->path; 4300 l->l_base = obj->mapbase; 4301 l->l_ld = obj->dynamic; 4302 l->l_addr = obj->relocbase; 4303 4304 if (r_debug.r_map == NULL) { 4305 r_debug.r_map = l; 4306 return; 4307 } 4308 4309 /* 4310 * Scan to the end of the list, but not past the entry for the 4311 * dynamic linker, which we want to keep at the very end. 4312 */ 4313 for (prev = r_debug.r_map; 4314 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4315 prev = prev->l_next) 4316 ; 4317 4318 /* Link in the new entry. */ 4319 l->l_prev = prev; 4320 l->l_next = prev->l_next; 4321 if (l->l_next != NULL) 4322 l->l_next->l_prev = l; 4323 prev->l_next = l; 4324 } 4325 4326 static void 4327 linkmap_delete(Obj_Entry *obj) 4328 { 4329 struct link_map *l; 4330 4331 l = &obj->linkmap; 4332 if (l->l_prev == NULL) { 4333 if ((r_debug.r_map = l->l_next) != NULL) 4334 l->l_next->l_prev = NULL; 4335 return; 4336 } 4337 4338 if ((l->l_prev->l_next = l->l_next) != NULL) 4339 l->l_next->l_prev = l->l_prev; 4340 } 4341 4342 /* 4343 * Function for the debugger to set a breakpoint on to gain control. 4344 * 4345 * The two parameters allow the debugger to easily find and determine 4346 * what the runtime loader is doing and to whom it is doing it. 4347 * 4348 * When the loadhook trap is hit (r_debug_state, set at program 4349 * initialization), the arguments can be found on the stack: 4350 * 4351 * +8 struct link_map *m 4352 * +4 struct r_debug *rd 4353 * +0 RetAddr 4354 */ 4355 void 4356 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4357 { 4358 /* 4359 * The following is a hack to force the compiler to emit calls to 4360 * this function, even when optimizing. If the function is empty, 4361 * the compiler is not obliged to emit any code for calls to it, 4362 * even when marked __noinline. However, gdb depends on those 4363 * calls being made. 4364 */ 4365 __compiler_membar(); 4366 } 4367 4368 /* 4369 * A function called after init routines have completed. This can be used to 4370 * break before a program's entry routine is called, and can be used when 4371 * main is not available in the symbol table. 4372 */ 4373 void 4374 _r_debug_postinit(struct link_map *m __unused) 4375 { 4376 4377 /* See r_debug_state(). */ 4378 __compiler_membar(); 4379 } 4380 4381 static void 4382 release_object(Obj_Entry *obj) 4383 { 4384 4385 if (obj->holdcount > 0) { 4386 obj->unholdfree = true; 4387 return; 4388 } 4389 munmap(obj->mapbase, obj->mapsize); 4390 linkmap_delete(obj); 4391 obj_free(obj); 4392 } 4393 4394 /* 4395 * Get address of the pointer variable in the main program. 4396 * Prefer non-weak symbol over the weak one. 4397 */ 4398 static const void ** 4399 get_program_var_addr(const char *name, RtldLockState *lockstate) 4400 { 4401 SymLook req; 4402 DoneList donelist; 4403 4404 symlook_init(&req, name); 4405 req.lockstate = lockstate; 4406 donelist_init(&donelist); 4407 if (symlook_global(&req, &donelist) != 0) 4408 return (NULL); 4409 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4410 return ((const void **)make_function_pointer(req.sym_out, 4411 req.defobj_out)); 4412 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4413 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4414 else 4415 return ((const void **)(req.defobj_out->relocbase + 4416 req.sym_out->st_value)); 4417 } 4418 4419 /* 4420 * Set a pointer variable in the main program to the given value. This 4421 * is used to set key variables such as "environ" before any of the 4422 * init functions are called. 4423 */ 4424 static void 4425 set_program_var(const char *name, const void *value) 4426 { 4427 const void **addr; 4428 4429 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4430 dbg("\"%s\": *%p <-- %p", name, addr, value); 4431 *addr = value; 4432 } 4433 } 4434 4435 /* 4436 * Search the global objects, including dependencies and main object, 4437 * for the given symbol. 4438 */ 4439 static int 4440 symlook_global(SymLook *req, DoneList *donelist) 4441 { 4442 SymLook req1; 4443 const Objlist_Entry *elm; 4444 int res; 4445 4446 symlook_init_from_req(&req1, req); 4447 4448 /* Search all objects loaded at program start up. */ 4449 if (req->defobj_out == NULL || (ld_dynamic_weak && 4450 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4451 res = symlook_list(&req1, &list_main, donelist); 4452 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4453 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4454 req->sym_out = req1.sym_out; 4455 req->defobj_out = req1.defobj_out; 4456 assert(req->defobj_out != NULL); 4457 } 4458 } 4459 4460 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4461 STAILQ_FOREACH(elm, &list_global, link) { 4462 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4463 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4464 break; 4465 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4466 if (res == 0 && (req->defobj_out == NULL || 4467 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4468 req->sym_out = req1.sym_out; 4469 req->defobj_out = req1.defobj_out; 4470 assert(req->defobj_out != NULL); 4471 } 4472 } 4473 4474 return (req->sym_out != NULL ? 0 : ESRCH); 4475 } 4476 4477 /* 4478 * Given a symbol name in a referencing object, find the corresponding 4479 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4480 * no definition was found. Returns a pointer to the Obj_Entry of the 4481 * defining object via the reference parameter DEFOBJ_OUT. 4482 */ 4483 static int 4484 symlook_default(SymLook *req, const Obj_Entry *refobj) 4485 { 4486 DoneList donelist; 4487 const Objlist_Entry *elm; 4488 SymLook req1; 4489 int res; 4490 4491 donelist_init(&donelist); 4492 symlook_init_from_req(&req1, req); 4493 4494 /* 4495 * Look first in the referencing object if linked symbolically, 4496 * and similarly handle protected symbols. 4497 */ 4498 res = symlook_obj(&req1, refobj); 4499 if (res == 0 && (refobj->symbolic || 4500 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4501 req->sym_out = req1.sym_out; 4502 req->defobj_out = req1.defobj_out; 4503 assert(req->defobj_out != NULL); 4504 } 4505 if (refobj->symbolic || req->defobj_out != NULL) 4506 donelist_check(&donelist, refobj); 4507 4508 symlook_global(req, &donelist); 4509 4510 /* Search all dlopened DAGs containing the referencing object. */ 4511 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4512 if (req->sym_out != NULL && (!ld_dynamic_weak || 4513 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4514 break; 4515 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4516 if (res == 0 && (req->sym_out == NULL || 4517 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4518 req->sym_out = req1.sym_out; 4519 req->defobj_out = req1.defobj_out; 4520 assert(req->defobj_out != NULL); 4521 } 4522 } 4523 4524 /* 4525 * Search the dynamic linker itself, and possibly resolve the 4526 * symbol from there. This is how the application links to 4527 * dynamic linker services such as dlopen. 4528 */ 4529 if (req->sym_out == NULL || 4530 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4531 res = symlook_obj(&req1, &obj_rtld); 4532 if (res == 0) { 4533 req->sym_out = req1.sym_out; 4534 req->defobj_out = req1.defobj_out; 4535 assert(req->defobj_out != NULL); 4536 } 4537 } 4538 4539 return (req->sym_out != NULL ? 0 : ESRCH); 4540 } 4541 4542 static int 4543 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4544 { 4545 const Elf_Sym *def; 4546 const Obj_Entry *defobj; 4547 const Objlist_Entry *elm; 4548 SymLook req1; 4549 int res; 4550 4551 def = NULL; 4552 defobj = NULL; 4553 STAILQ_FOREACH(elm, objlist, link) { 4554 if (donelist_check(dlp, elm->obj)) 4555 continue; 4556 symlook_init_from_req(&req1, req); 4557 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4558 if (def == NULL || (ld_dynamic_weak && 4559 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4560 def = req1.sym_out; 4561 defobj = req1.defobj_out; 4562 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4563 break; 4564 } 4565 } 4566 } 4567 if (def != NULL) { 4568 req->sym_out = def; 4569 req->defobj_out = defobj; 4570 return (0); 4571 } 4572 return (ESRCH); 4573 } 4574 4575 /* 4576 * Search the chain of DAGS cointed to by the given Needed_Entry 4577 * for a symbol of the given name. Each DAG is scanned completely 4578 * before advancing to the next one. Returns a pointer to the symbol, 4579 * or NULL if no definition was found. 4580 */ 4581 static int 4582 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4583 { 4584 const Elf_Sym *def; 4585 const Needed_Entry *n; 4586 const Obj_Entry *defobj; 4587 SymLook req1; 4588 int res; 4589 4590 def = NULL; 4591 defobj = NULL; 4592 symlook_init_from_req(&req1, req); 4593 for (n = needed; n != NULL; n = n->next) { 4594 if (n->obj == NULL || 4595 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4596 continue; 4597 if (def == NULL || (ld_dynamic_weak && 4598 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4599 def = req1.sym_out; 4600 defobj = req1.defobj_out; 4601 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4602 break; 4603 } 4604 } 4605 if (def != NULL) { 4606 req->sym_out = def; 4607 req->defobj_out = defobj; 4608 return (0); 4609 } 4610 return (ESRCH); 4611 } 4612 4613 /* 4614 * Search the symbol table of a single shared object for a symbol of 4615 * the given name and version, if requested. Returns a pointer to the 4616 * symbol, or NULL if no definition was found. If the object is 4617 * filter, return filtered symbol from filtee. 4618 * 4619 * The symbol's hash value is passed in for efficiency reasons; that 4620 * eliminates many recomputations of the hash value. 4621 */ 4622 int 4623 symlook_obj(SymLook *req, const Obj_Entry *obj) 4624 { 4625 DoneList donelist; 4626 SymLook req1; 4627 int flags, res, mres; 4628 4629 /* 4630 * If there is at least one valid hash at this point, we prefer to 4631 * use the faster GNU version if available. 4632 */ 4633 if (obj->valid_hash_gnu) 4634 mres = symlook_obj1_gnu(req, obj); 4635 else if (obj->valid_hash_sysv) 4636 mres = symlook_obj1_sysv(req, obj); 4637 else 4638 return (EINVAL); 4639 4640 if (mres == 0) { 4641 if (obj->needed_filtees != NULL) { 4642 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4643 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4644 donelist_init(&donelist); 4645 symlook_init_from_req(&req1, req); 4646 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4647 if (res == 0) { 4648 req->sym_out = req1.sym_out; 4649 req->defobj_out = req1.defobj_out; 4650 } 4651 return (res); 4652 } 4653 if (obj->needed_aux_filtees != NULL) { 4654 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4655 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4656 donelist_init(&donelist); 4657 symlook_init_from_req(&req1, req); 4658 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4659 if (res == 0) { 4660 req->sym_out = req1.sym_out; 4661 req->defobj_out = req1.defobj_out; 4662 return (res); 4663 } 4664 } 4665 } 4666 return (mres); 4667 } 4668 4669 /* Symbol match routine common to both hash functions */ 4670 static bool 4671 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4672 const unsigned long symnum) 4673 { 4674 Elf_Versym verndx; 4675 const Elf_Sym *symp; 4676 const char *strp; 4677 4678 symp = obj->symtab + symnum; 4679 strp = obj->strtab + symp->st_name; 4680 4681 switch (ELF_ST_TYPE(symp->st_info)) { 4682 case STT_FUNC: 4683 case STT_NOTYPE: 4684 case STT_OBJECT: 4685 case STT_COMMON: 4686 case STT_GNU_IFUNC: 4687 if (symp->st_value == 0) 4688 return (false); 4689 /* fallthrough */ 4690 case STT_TLS: 4691 if (symp->st_shndx != SHN_UNDEF) 4692 break; 4693 #ifndef __mips__ 4694 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4695 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4696 break; 4697 #endif 4698 /* fallthrough */ 4699 default: 4700 return (false); 4701 } 4702 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4703 return (false); 4704 4705 if (req->ventry == NULL) { 4706 if (obj->versyms != NULL) { 4707 verndx = VER_NDX(obj->versyms[symnum]); 4708 if (verndx > obj->vernum) { 4709 _rtld_error( 4710 "%s: symbol %s references wrong version %d", 4711 obj->path, obj->strtab + symnum, verndx); 4712 return (false); 4713 } 4714 /* 4715 * If we are not called from dlsym (i.e. this 4716 * is a normal relocation from unversioned 4717 * binary), accept the symbol immediately if 4718 * it happens to have first version after this 4719 * shared object became versioned. Otherwise, 4720 * if symbol is versioned and not hidden, 4721 * remember it. If it is the only symbol with 4722 * this name exported by the shared object, it 4723 * will be returned as a match by the calling 4724 * function. If symbol is global (verndx < 2) 4725 * accept it unconditionally. 4726 */ 4727 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4728 verndx == VER_NDX_GIVEN) { 4729 result->sym_out = symp; 4730 return (true); 4731 } 4732 else if (verndx >= VER_NDX_GIVEN) { 4733 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4734 == 0) { 4735 if (result->vsymp == NULL) 4736 result->vsymp = symp; 4737 result->vcount++; 4738 } 4739 return (false); 4740 } 4741 } 4742 result->sym_out = symp; 4743 return (true); 4744 } 4745 if (obj->versyms == NULL) { 4746 if (object_match_name(obj, req->ventry->name)) { 4747 _rtld_error("%s: object %s should provide version %s " 4748 "for symbol %s", obj_rtld.path, obj->path, 4749 req->ventry->name, obj->strtab + symnum); 4750 return (false); 4751 } 4752 } else { 4753 verndx = VER_NDX(obj->versyms[symnum]); 4754 if (verndx > obj->vernum) { 4755 _rtld_error("%s: symbol %s references wrong version %d", 4756 obj->path, obj->strtab + symnum, verndx); 4757 return (false); 4758 } 4759 if (obj->vertab[verndx].hash != req->ventry->hash || 4760 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4761 /* 4762 * Version does not match. Look if this is a 4763 * global symbol and if it is not hidden. If 4764 * global symbol (verndx < 2) is available, 4765 * use it. Do not return symbol if we are 4766 * called by dlvsym, because dlvsym looks for 4767 * a specific version and default one is not 4768 * what dlvsym wants. 4769 */ 4770 if ((req->flags & SYMLOOK_DLSYM) || 4771 (verndx >= VER_NDX_GIVEN) || 4772 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4773 return (false); 4774 } 4775 } 4776 result->sym_out = symp; 4777 return (true); 4778 } 4779 4780 /* 4781 * Search for symbol using SysV hash function. 4782 * obj->buckets is known not to be NULL at this point; the test for this was 4783 * performed with the obj->valid_hash_sysv assignment. 4784 */ 4785 static int 4786 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4787 { 4788 unsigned long symnum; 4789 Sym_Match_Result matchres; 4790 4791 matchres.sym_out = NULL; 4792 matchres.vsymp = NULL; 4793 matchres.vcount = 0; 4794 4795 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4796 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4797 if (symnum >= obj->nchains) 4798 return (ESRCH); /* Bad object */ 4799 4800 if (matched_symbol(req, obj, &matchres, symnum)) { 4801 req->sym_out = matchres.sym_out; 4802 req->defobj_out = obj; 4803 return (0); 4804 } 4805 } 4806 if (matchres.vcount == 1) { 4807 req->sym_out = matchres.vsymp; 4808 req->defobj_out = obj; 4809 return (0); 4810 } 4811 return (ESRCH); 4812 } 4813 4814 /* Search for symbol using GNU hash function */ 4815 static int 4816 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4817 { 4818 Elf_Addr bloom_word; 4819 const Elf32_Word *hashval; 4820 Elf32_Word bucket; 4821 Sym_Match_Result matchres; 4822 unsigned int h1, h2; 4823 unsigned long symnum; 4824 4825 matchres.sym_out = NULL; 4826 matchres.vsymp = NULL; 4827 matchres.vcount = 0; 4828 4829 /* Pick right bitmask word from Bloom filter array */ 4830 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4831 obj->maskwords_bm_gnu]; 4832 4833 /* Calculate modulus word size of gnu hash and its derivative */ 4834 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4835 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4836 4837 /* Filter out the "definitely not in set" queries */ 4838 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4839 return (ESRCH); 4840 4841 /* Locate hash chain and corresponding value element*/ 4842 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4843 if (bucket == 0) 4844 return (ESRCH); 4845 hashval = &obj->chain_zero_gnu[bucket]; 4846 do { 4847 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4848 symnum = hashval - obj->chain_zero_gnu; 4849 if (matched_symbol(req, obj, &matchres, symnum)) { 4850 req->sym_out = matchres.sym_out; 4851 req->defobj_out = obj; 4852 return (0); 4853 } 4854 } 4855 } while ((*hashval++ & 1) == 0); 4856 if (matchres.vcount == 1) { 4857 req->sym_out = matchres.vsymp; 4858 req->defobj_out = obj; 4859 return (0); 4860 } 4861 return (ESRCH); 4862 } 4863 4864 static void 4865 trace_loaded_objects(Obj_Entry *obj) 4866 { 4867 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4868 int c; 4869 4870 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4871 NULL) 4872 main_local = ""; 4873 4874 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4875 fmt1 = "\t%o => %p (%x)\n"; 4876 4877 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4878 fmt2 = "\t%o (%x)\n"; 4879 4880 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4881 4882 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4883 Needed_Entry *needed; 4884 const char *name, *path; 4885 bool is_lib; 4886 4887 if (obj->marker) 4888 continue; 4889 if (list_containers && obj->needed != NULL) 4890 rtld_printf("%s:\n", obj->path); 4891 for (needed = obj->needed; needed; needed = needed->next) { 4892 if (needed->obj != NULL) { 4893 if (needed->obj->traced && !list_containers) 4894 continue; 4895 needed->obj->traced = true; 4896 path = needed->obj->path; 4897 } else 4898 path = "not found"; 4899 4900 name = obj->strtab + needed->name; 4901 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4902 4903 fmt = is_lib ? fmt1 : fmt2; 4904 while ((c = *fmt++) != '\0') { 4905 switch (c) { 4906 default: 4907 rtld_putchar(c); 4908 continue; 4909 case '\\': 4910 switch (c = *fmt) { 4911 case '\0': 4912 continue; 4913 case 'n': 4914 rtld_putchar('\n'); 4915 break; 4916 case 't': 4917 rtld_putchar('\t'); 4918 break; 4919 } 4920 break; 4921 case '%': 4922 switch (c = *fmt) { 4923 case '\0': 4924 continue; 4925 case '%': 4926 default: 4927 rtld_putchar(c); 4928 break; 4929 case 'A': 4930 rtld_putstr(main_local); 4931 break; 4932 case 'a': 4933 rtld_putstr(obj_main->path); 4934 break; 4935 case 'o': 4936 rtld_putstr(name); 4937 break; 4938 #if 0 4939 case 'm': 4940 rtld_printf("%d", sodp->sod_major); 4941 break; 4942 case 'n': 4943 rtld_printf("%d", sodp->sod_minor); 4944 break; 4945 #endif 4946 case 'p': 4947 rtld_putstr(path); 4948 break; 4949 case 'x': 4950 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4951 0); 4952 break; 4953 } 4954 break; 4955 } 4956 ++fmt; 4957 } 4958 } 4959 } 4960 } 4961 4962 /* 4963 * Unload a dlopened object and its dependencies from memory and from 4964 * our data structures. It is assumed that the DAG rooted in the 4965 * object has already been unreferenced, and that the object has a 4966 * reference count of 0. 4967 */ 4968 static void 4969 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4970 { 4971 Obj_Entry marker, *obj, *next; 4972 4973 assert(root->refcount == 0); 4974 4975 /* 4976 * Pass over the DAG removing unreferenced objects from 4977 * appropriate lists. 4978 */ 4979 unlink_object(root); 4980 4981 /* Unmap all objects that are no longer referenced. */ 4982 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4983 next = TAILQ_NEXT(obj, next); 4984 if (obj->marker || obj->refcount != 0) 4985 continue; 4986 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4987 obj->mapsize, 0, obj->path); 4988 dbg("unloading \"%s\"", obj->path); 4989 /* 4990 * Unlink the object now to prevent new references from 4991 * being acquired while the bind lock is dropped in 4992 * recursive dlclose() invocations. 4993 */ 4994 TAILQ_REMOVE(&obj_list, obj, next); 4995 obj_count--; 4996 4997 if (obj->filtees_loaded) { 4998 if (next != NULL) { 4999 init_marker(&marker); 5000 TAILQ_INSERT_BEFORE(next, &marker, next); 5001 unload_filtees(obj, lockstate); 5002 next = TAILQ_NEXT(&marker, next); 5003 TAILQ_REMOVE(&obj_list, &marker, next); 5004 } else 5005 unload_filtees(obj, lockstate); 5006 } 5007 release_object(obj); 5008 } 5009 } 5010 5011 static void 5012 unlink_object(Obj_Entry *root) 5013 { 5014 Objlist_Entry *elm; 5015 5016 if (root->refcount == 0) { 5017 /* Remove the object from the RTLD_GLOBAL list. */ 5018 objlist_remove(&list_global, root); 5019 5020 /* Remove the object from all objects' DAG lists. */ 5021 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5022 objlist_remove(&elm->obj->dldags, root); 5023 if (elm->obj != root) 5024 unlink_object(elm->obj); 5025 } 5026 } 5027 } 5028 5029 static void 5030 ref_dag(Obj_Entry *root) 5031 { 5032 Objlist_Entry *elm; 5033 5034 assert(root->dag_inited); 5035 STAILQ_FOREACH(elm, &root->dagmembers, link) 5036 elm->obj->refcount++; 5037 } 5038 5039 static void 5040 unref_dag(Obj_Entry *root) 5041 { 5042 Objlist_Entry *elm; 5043 5044 assert(root->dag_inited); 5045 STAILQ_FOREACH(elm, &root->dagmembers, link) 5046 elm->obj->refcount--; 5047 } 5048 5049 /* 5050 * Common code for MD __tls_get_addr(). 5051 */ 5052 static void * 5053 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5054 { 5055 Elf_Addr *newdtv, *dtv; 5056 RtldLockState lockstate; 5057 int to_copy; 5058 5059 dtv = *dtvp; 5060 /* Check dtv generation in case new modules have arrived */ 5061 if (dtv[0] != tls_dtv_generation) { 5062 if (!locked) 5063 wlock_acquire(rtld_bind_lock, &lockstate); 5064 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5065 to_copy = dtv[1]; 5066 if (to_copy > tls_max_index) 5067 to_copy = tls_max_index; 5068 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5069 newdtv[0] = tls_dtv_generation; 5070 newdtv[1] = tls_max_index; 5071 free(dtv); 5072 if (!locked) 5073 lock_release(rtld_bind_lock, &lockstate); 5074 dtv = *dtvp = newdtv; 5075 } 5076 5077 /* Dynamically allocate module TLS if necessary */ 5078 if (dtv[index + 1] == 0) { 5079 /* Signal safe, wlock will block out signals. */ 5080 if (!locked) 5081 wlock_acquire(rtld_bind_lock, &lockstate); 5082 if (!dtv[index + 1]) 5083 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5084 if (!locked) 5085 lock_release(rtld_bind_lock, &lockstate); 5086 } 5087 return ((void *)(dtv[index + 1] + offset)); 5088 } 5089 5090 void * 5091 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 5092 { 5093 Elf_Addr *dtv; 5094 5095 dtv = *dtvp; 5096 /* Check dtv generation in case new modules have arrived */ 5097 if (__predict_true(dtv[0] == tls_dtv_generation && 5098 dtv[index + 1] != 0)) 5099 return ((void *)(dtv[index + 1] + offset)); 5100 return (tls_get_addr_slow(dtvp, index, offset, false)); 5101 } 5102 5103 #ifdef TLS_VARIANT_I 5104 5105 /* 5106 * Return pointer to allocated TLS block 5107 */ 5108 static void * 5109 get_tls_block_ptr(void *tcb, size_t tcbsize) 5110 { 5111 size_t extra_size, post_size, pre_size, tls_block_size; 5112 size_t tls_init_align; 5113 5114 tls_init_align = MAX(obj_main->tlsalign, 1); 5115 5116 /* Compute fragments sizes. */ 5117 extra_size = tcbsize - TLS_TCB_SIZE; 5118 post_size = calculate_tls_post_size(tls_init_align); 5119 tls_block_size = tcbsize + post_size; 5120 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5121 5122 return ((char *)tcb - pre_size - extra_size); 5123 } 5124 5125 /* 5126 * Allocate Static TLS using the Variant I method. 5127 * 5128 * For details on the layout, see lib/libc/gen/tls.c. 5129 * 5130 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5131 * it is based on tls_last_offset, and TLS offsets here are really TCB 5132 * offsets, whereas libc's tls_static_space is just the executable's static 5133 * TLS segment. 5134 */ 5135 void * 5136 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5137 { 5138 Obj_Entry *obj; 5139 char *tls_block; 5140 Elf_Addr *dtv, **tcb; 5141 Elf_Addr addr; 5142 Elf_Addr i; 5143 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5144 size_t tls_init_align, tls_init_offset; 5145 5146 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5147 return (oldtcb); 5148 5149 assert(tcbsize >= TLS_TCB_SIZE); 5150 maxalign = MAX(tcbalign, tls_static_max_align); 5151 tls_init_align = MAX(obj_main->tlsalign, 1); 5152 5153 /* Compute fragmets sizes. */ 5154 extra_size = tcbsize - TLS_TCB_SIZE; 5155 post_size = calculate_tls_post_size(tls_init_align); 5156 tls_block_size = tcbsize + post_size; 5157 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5158 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5159 5160 /* Allocate whole TLS block */ 5161 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5162 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5163 5164 if (oldtcb != NULL) { 5165 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5166 tls_static_space); 5167 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5168 5169 /* Adjust the DTV. */ 5170 dtv = tcb[0]; 5171 for (i = 0; i < dtv[1]; i++) { 5172 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5173 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5174 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5175 } 5176 } 5177 } else { 5178 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5179 tcb[0] = dtv; 5180 dtv[0] = tls_dtv_generation; 5181 dtv[1] = tls_max_index; 5182 5183 for (obj = globallist_curr(objs); obj != NULL; 5184 obj = globallist_next(obj)) { 5185 if (obj->tlsoffset == 0) 5186 continue; 5187 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5188 addr = (Elf_Addr)tcb + obj->tlsoffset; 5189 if (tls_init_offset > 0) 5190 memset((void *)addr, 0, tls_init_offset); 5191 if (obj->tlsinitsize > 0) { 5192 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5193 obj->tlsinitsize); 5194 } 5195 if (obj->tlssize > obj->tlsinitsize) { 5196 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5197 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5198 } 5199 dtv[obj->tlsindex + 1] = addr; 5200 } 5201 } 5202 5203 return (tcb); 5204 } 5205 5206 void 5207 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5208 { 5209 Elf_Addr *dtv; 5210 Elf_Addr tlsstart, tlsend; 5211 size_t post_size; 5212 size_t dtvsize, i, tls_init_align; 5213 5214 assert(tcbsize >= TLS_TCB_SIZE); 5215 tls_init_align = MAX(obj_main->tlsalign, 1); 5216 5217 /* Compute fragments sizes. */ 5218 post_size = calculate_tls_post_size(tls_init_align); 5219 5220 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5221 tlsend = (Elf_Addr)tcb + tls_static_space; 5222 5223 dtv = *(Elf_Addr **)tcb; 5224 dtvsize = dtv[1]; 5225 for (i = 0; i < dtvsize; i++) { 5226 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5227 free((void*)dtv[i+2]); 5228 } 5229 } 5230 free(dtv); 5231 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5232 } 5233 5234 #endif /* TLS_VARIANT_I */ 5235 5236 #ifdef TLS_VARIANT_II 5237 5238 /* 5239 * Allocate Static TLS using the Variant II method. 5240 */ 5241 void * 5242 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5243 { 5244 Obj_Entry *obj; 5245 size_t size, ralign; 5246 char *tls; 5247 Elf_Addr *dtv, *olddtv; 5248 Elf_Addr segbase, oldsegbase, addr; 5249 size_t i; 5250 5251 ralign = tcbalign; 5252 if (tls_static_max_align > ralign) 5253 ralign = tls_static_max_align; 5254 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5255 5256 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5257 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5258 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5259 5260 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5261 ((Elf_Addr*)segbase)[0] = segbase; 5262 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5263 5264 dtv[0] = tls_dtv_generation; 5265 dtv[1] = tls_max_index; 5266 5267 if (oldtls) { 5268 /* 5269 * Copy the static TLS block over whole. 5270 */ 5271 oldsegbase = (Elf_Addr) oldtls; 5272 memcpy((void *)(segbase - tls_static_space), 5273 (const void *)(oldsegbase - tls_static_space), 5274 tls_static_space); 5275 5276 /* 5277 * If any dynamic TLS blocks have been created tls_get_addr(), 5278 * move them over. 5279 */ 5280 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5281 for (i = 0; i < olddtv[1]; i++) { 5282 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5283 dtv[i+2] = olddtv[i+2]; 5284 olddtv[i+2] = 0; 5285 } 5286 } 5287 5288 /* 5289 * We assume that this block was the one we created with 5290 * allocate_initial_tls(). 5291 */ 5292 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5293 } else { 5294 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5295 if (obj->marker || obj->tlsoffset == 0) 5296 continue; 5297 addr = segbase - obj->tlsoffset; 5298 memset((void*)(addr + obj->tlsinitsize), 5299 0, obj->tlssize - obj->tlsinitsize); 5300 if (obj->tlsinit) { 5301 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5302 obj->static_tls_copied = true; 5303 } 5304 dtv[obj->tlsindex + 1] = addr; 5305 } 5306 } 5307 5308 return (void*) segbase; 5309 } 5310 5311 void 5312 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5313 { 5314 Elf_Addr* dtv; 5315 size_t size, ralign; 5316 int dtvsize, i; 5317 Elf_Addr tlsstart, tlsend; 5318 5319 /* 5320 * Figure out the size of the initial TLS block so that we can 5321 * find stuff which ___tls_get_addr() allocated dynamically. 5322 */ 5323 ralign = tcbalign; 5324 if (tls_static_max_align > ralign) 5325 ralign = tls_static_max_align; 5326 size = roundup(tls_static_space, ralign); 5327 5328 dtv = ((Elf_Addr**)tls)[1]; 5329 dtvsize = dtv[1]; 5330 tlsend = (Elf_Addr) tls; 5331 tlsstart = tlsend - size; 5332 for (i = 0; i < dtvsize; i++) { 5333 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5334 free_aligned((void *)dtv[i + 2]); 5335 } 5336 } 5337 5338 free_aligned((void *)tlsstart); 5339 free((void*) dtv); 5340 } 5341 5342 #endif /* TLS_VARIANT_II */ 5343 5344 /* 5345 * Allocate TLS block for module with given index. 5346 */ 5347 void * 5348 allocate_module_tls(int index) 5349 { 5350 Obj_Entry *obj; 5351 char *p; 5352 5353 TAILQ_FOREACH(obj, &obj_list, next) { 5354 if (obj->marker) 5355 continue; 5356 if (obj->tlsindex == index) 5357 break; 5358 } 5359 if (obj == NULL) { 5360 _rtld_error("Can't find module with TLS index %d", index); 5361 rtld_die(); 5362 } 5363 5364 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5365 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5366 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5367 return (p); 5368 } 5369 5370 bool 5371 allocate_tls_offset(Obj_Entry *obj) 5372 { 5373 size_t off; 5374 5375 if (obj->tls_done) 5376 return true; 5377 5378 if (obj->tlssize == 0) { 5379 obj->tls_done = true; 5380 return true; 5381 } 5382 5383 if (tls_last_offset == 0) 5384 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5385 obj->tlspoffset); 5386 else 5387 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5388 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5389 5390 obj->tlsoffset = off; 5391 #ifdef TLS_VARIANT_I 5392 off += obj->tlssize; 5393 #endif 5394 5395 /* 5396 * If we have already fixed the size of the static TLS block, we 5397 * must stay within that size. When allocating the static TLS, we 5398 * leave a small amount of space spare to be used for dynamically 5399 * loading modules which use static TLS. 5400 */ 5401 if (tls_static_space != 0) { 5402 if (off > tls_static_space) 5403 return false; 5404 } else if (obj->tlsalign > tls_static_max_align) { 5405 tls_static_max_align = obj->tlsalign; 5406 } 5407 5408 tls_last_offset = off; 5409 tls_last_size = obj->tlssize; 5410 obj->tls_done = true; 5411 5412 return true; 5413 } 5414 5415 void 5416 free_tls_offset(Obj_Entry *obj) 5417 { 5418 5419 /* 5420 * If we were the last thing to allocate out of the static TLS 5421 * block, we give our space back to the 'allocator'. This is a 5422 * simplistic workaround to allow libGL.so.1 to be loaded and 5423 * unloaded multiple times. 5424 */ 5425 size_t off = obj->tlsoffset; 5426 #ifdef TLS_VARIANT_I 5427 off += obj->tlssize; 5428 #endif 5429 if (off == tls_last_offset) { 5430 tls_last_offset -= obj->tlssize; 5431 tls_last_size = 0; 5432 } 5433 } 5434 5435 void * 5436 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5437 { 5438 void *ret; 5439 RtldLockState lockstate; 5440 5441 wlock_acquire(rtld_bind_lock, &lockstate); 5442 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5443 tcbsize, tcbalign); 5444 lock_release(rtld_bind_lock, &lockstate); 5445 return (ret); 5446 } 5447 5448 void 5449 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5450 { 5451 RtldLockState lockstate; 5452 5453 wlock_acquire(rtld_bind_lock, &lockstate); 5454 free_tls(tcb, tcbsize, tcbalign); 5455 lock_release(rtld_bind_lock, &lockstate); 5456 } 5457 5458 static void 5459 object_add_name(Obj_Entry *obj, const char *name) 5460 { 5461 Name_Entry *entry; 5462 size_t len; 5463 5464 len = strlen(name); 5465 entry = malloc(sizeof(Name_Entry) + len); 5466 5467 if (entry != NULL) { 5468 strcpy(entry->name, name); 5469 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5470 } 5471 } 5472 5473 static int 5474 object_match_name(const Obj_Entry *obj, const char *name) 5475 { 5476 Name_Entry *entry; 5477 5478 STAILQ_FOREACH(entry, &obj->names, link) { 5479 if (strcmp(name, entry->name) == 0) 5480 return (1); 5481 } 5482 return (0); 5483 } 5484 5485 static Obj_Entry * 5486 locate_dependency(const Obj_Entry *obj, const char *name) 5487 { 5488 const Objlist_Entry *entry; 5489 const Needed_Entry *needed; 5490 5491 STAILQ_FOREACH(entry, &list_main, link) { 5492 if (object_match_name(entry->obj, name)) 5493 return entry->obj; 5494 } 5495 5496 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5497 if (strcmp(obj->strtab + needed->name, name) == 0 || 5498 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5499 /* 5500 * If there is DT_NEEDED for the name we are looking for, 5501 * we are all set. Note that object might not be found if 5502 * dependency was not loaded yet, so the function can 5503 * return NULL here. This is expected and handled 5504 * properly by the caller. 5505 */ 5506 return (needed->obj); 5507 } 5508 } 5509 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5510 obj->path, name); 5511 rtld_die(); 5512 } 5513 5514 static int 5515 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5516 const Elf_Vernaux *vna) 5517 { 5518 const Elf_Verdef *vd; 5519 const char *vername; 5520 5521 vername = refobj->strtab + vna->vna_name; 5522 vd = depobj->verdef; 5523 if (vd == NULL) { 5524 _rtld_error("%s: version %s required by %s not defined", 5525 depobj->path, vername, refobj->path); 5526 return (-1); 5527 } 5528 for (;;) { 5529 if (vd->vd_version != VER_DEF_CURRENT) { 5530 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5531 depobj->path, vd->vd_version); 5532 return (-1); 5533 } 5534 if (vna->vna_hash == vd->vd_hash) { 5535 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5536 ((const char *)vd + vd->vd_aux); 5537 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5538 return (0); 5539 } 5540 if (vd->vd_next == 0) 5541 break; 5542 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5543 } 5544 if (vna->vna_flags & VER_FLG_WEAK) 5545 return (0); 5546 _rtld_error("%s: version %s required by %s not found", 5547 depobj->path, vername, refobj->path); 5548 return (-1); 5549 } 5550 5551 static int 5552 rtld_verify_object_versions(Obj_Entry *obj) 5553 { 5554 const Elf_Verneed *vn; 5555 const Elf_Verdef *vd; 5556 const Elf_Verdaux *vda; 5557 const Elf_Vernaux *vna; 5558 const Obj_Entry *depobj; 5559 int maxvernum, vernum; 5560 5561 if (obj->ver_checked) 5562 return (0); 5563 obj->ver_checked = true; 5564 5565 maxvernum = 0; 5566 /* 5567 * Walk over defined and required version records and figure out 5568 * max index used by any of them. Do very basic sanity checking 5569 * while there. 5570 */ 5571 vn = obj->verneed; 5572 while (vn != NULL) { 5573 if (vn->vn_version != VER_NEED_CURRENT) { 5574 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5575 obj->path, vn->vn_version); 5576 return (-1); 5577 } 5578 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5579 for (;;) { 5580 vernum = VER_NEED_IDX(vna->vna_other); 5581 if (vernum > maxvernum) 5582 maxvernum = vernum; 5583 if (vna->vna_next == 0) 5584 break; 5585 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5586 } 5587 if (vn->vn_next == 0) 5588 break; 5589 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5590 } 5591 5592 vd = obj->verdef; 5593 while (vd != NULL) { 5594 if (vd->vd_version != VER_DEF_CURRENT) { 5595 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5596 obj->path, vd->vd_version); 5597 return (-1); 5598 } 5599 vernum = VER_DEF_IDX(vd->vd_ndx); 5600 if (vernum > maxvernum) 5601 maxvernum = vernum; 5602 if (vd->vd_next == 0) 5603 break; 5604 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5605 } 5606 5607 if (maxvernum == 0) 5608 return (0); 5609 5610 /* 5611 * Store version information in array indexable by version index. 5612 * Verify that object version requirements are satisfied along the 5613 * way. 5614 */ 5615 obj->vernum = maxvernum + 1; 5616 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5617 5618 vd = obj->verdef; 5619 while (vd != NULL) { 5620 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5621 vernum = VER_DEF_IDX(vd->vd_ndx); 5622 assert(vernum <= maxvernum); 5623 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5624 obj->vertab[vernum].hash = vd->vd_hash; 5625 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5626 obj->vertab[vernum].file = NULL; 5627 obj->vertab[vernum].flags = 0; 5628 } 5629 if (vd->vd_next == 0) 5630 break; 5631 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5632 } 5633 5634 vn = obj->verneed; 5635 while (vn != NULL) { 5636 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5637 if (depobj == NULL) 5638 return (-1); 5639 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5640 for (;;) { 5641 if (check_object_provided_version(obj, depobj, vna)) 5642 return (-1); 5643 vernum = VER_NEED_IDX(vna->vna_other); 5644 assert(vernum <= maxvernum); 5645 obj->vertab[vernum].hash = vna->vna_hash; 5646 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5647 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5648 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5649 VER_INFO_HIDDEN : 0; 5650 if (vna->vna_next == 0) 5651 break; 5652 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5653 } 5654 if (vn->vn_next == 0) 5655 break; 5656 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5657 } 5658 return 0; 5659 } 5660 5661 static int 5662 rtld_verify_versions(const Objlist *objlist) 5663 { 5664 Objlist_Entry *entry; 5665 int rc; 5666 5667 rc = 0; 5668 STAILQ_FOREACH(entry, objlist, link) { 5669 /* 5670 * Skip dummy objects or objects that have their version requirements 5671 * already checked. 5672 */ 5673 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5674 continue; 5675 if (rtld_verify_object_versions(entry->obj) == -1) { 5676 rc = -1; 5677 if (ld_tracing == NULL) 5678 break; 5679 } 5680 } 5681 if (rc == 0 || ld_tracing != NULL) 5682 rc = rtld_verify_object_versions(&obj_rtld); 5683 return rc; 5684 } 5685 5686 const Ver_Entry * 5687 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5688 { 5689 Elf_Versym vernum; 5690 5691 if (obj->vertab) { 5692 vernum = VER_NDX(obj->versyms[symnum]); 5693 if (vernum >= obj->vernum) { 5694 _rtld_error("%s: symbol %s has wrong verneed value %d", 5695 obj->path, obj->strtab + symnum, vernum); 5696 } else if (obj->vertab[vernum].hash != 0) { 5697 return &obj->vertab[vernum]; 5698 } 5699 } 5700 return NULL; 5701 } 5702 5703 int 5704 _rtld_get_stack_prot(void) 5705 { 5706 5707 return (stack_prot); 5708 } 5709 5710 int 5711 _rtld_is_dlopened(void *arg) 5712 { 5713 Obj_Entry *obj; 5714 RtldLockState lockstate; 5715 int res; 5716 5717 rlock_acquire(rtld_bind_lock, &lockstate); 5718 obj = dlcheck(arg); 5719 if (obj == NULL) 5720 obj = obj_from_addr(arg); 5721 if (obj == NULL) { 5722 _rtld_error("No shared object contains address"); 5723 lock_release(rtld_bind_lock, &lockstate); 5724 return (-1); 5725 } 5726 res = obj->dlopened ? 1 : 0; 5727 lock_release(rtld_bind_lock, &lockstate); 5728 return (res); 5729 } 5730 5731 static int 5732 obj_remap_relro(Obj_Entry *obj, int prot) 5733 { 5734 5735 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5736 prot) == -1) { 5737 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5738 obj->path, prot, rtld_strerror(errno)); 5739 return (-1); 5740 } 5741 return (0); 5742 } 5743 5744 static int 5745 obj_disable_relro(Obj_Entry *obj) 5746 { 5747 5748 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5749 } 5750 5751 static int 5752 obj_enforce_relro(Obj_Entry *obj) 5753 { 5754 5755 return (obj_remap_relro(obj, PROT_READ)); 5756 } 5757 5758 static void 5759 map_stacks_exec(RtldLockState *lockstate) 5760 { 5761 void (*thr_map_stacks_exec)(void); 5762 5763 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5764 return; 5765 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5766 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5767 if (thr_map_stacks_exec != NULL) { 5768 stack_prot |= PROT_EXEC; 5769 thr_map_stacks_exec(); 5770 } 5771 } 5772 5773 static void 5774 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5775 { 5776 Objlist_Entry *elm; 5777 Obj_Entry *obj; 5778 void (*distrib)(size_t, void *, size_t, size_t); 5779 5780 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5781 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5782 if (distrib == NULL) 5783 return; 5784 STAILQ_FOREACH(elm, list, link) { 5785 obj = elm->obj; 5786 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5787 continue; 5788 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5789 obj->tlssize); 5790 obj->static_tls_copied = true; 5791 } 5792 } 5793 5794 void 5795 symlook_init(SymLook *dst, const char *name) 5796 { 5797 5798 bzero(dst, sizeof(*dst)); 5799 dst->name = name; 5800 dst->hash = elf_hash(name); 5801 dst->hash_gnu = gnu_hash(name); 5802 } 5803 5804 static void 5805 symlook_init_from_req(SymLook *dst, const SymLook *src) 5806 { 5807 5808 dst->name = src->name; 5809 dst->hash = src->hash; 5810 dst->hash_gnu = src->hash_gnu; 5811 dst->ventry = src->ventry; 5812 dst->flags = src->flags; 5813 dst->defobj_out = NULL; 5814 dst->sym_out = NULL; 5815 dst->lockstate = src->lockstate; 5816 } 5817 5818 static int 5819 open_binary_fd(const char *argv0, bool search_in_path, 5820 const char **binpath_res) 5821 { 5822 char *binpath, *pathenv, *pe, *res1; 5823 const char *res; 5824 int fd; 5825 5826 binpath = NULL; 5827 res = NULL; 5828 if (search_in_path && strchr(argv0, '/') == NULL) { 5829 binpath = xmalloc(PATH_MAX); 5830 pathenv = getenv("PATH"); 5831 if (pathenv == NULL) { 5832 _rtld_error("-p and no PATH environment variable"); 5833 rtld_die(); 5834 } 5835 pathenv = strdup(pathenv); 5836 if (pathenv == NULL) { 5837 _rtld_error("Cannot allocate memory"); 5838 rtld_die(); 5839 } 5840 fd = -1; 5841 errno = ENOENT; 5842 while ((pe = strsep(&pathenv, ":")) != NULL) { 5843 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5844 continue; 5845 if (binpath[0] != '\0' && 5846 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5847 continue; 5848 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5849 continue; 5850 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5851 if (fd != -1 || errno != ENOENT) { 5852 res = binpath; 5853 break; 5854 } 5855 } 5856 free(pathenv); 5857 } else { 5858 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5859 res = argv0; 5860 } 5861 5862 if (fd == -1) { 5863 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5864 rtld_die(); 5865 } 5866 if (res != NULL && res[0] != '/') { 5867 res1 = xmalloc(PATH_MAX); 5868 if (realpath(res, res1) != NULL) { 5869 if (res != argv0) 5870 free(__DECONST(char *, res)); 5871 res = res1; 5872 } else { 5873 free(res1); 5874 } 5875 } 5876 *binpath_res = res; 5877 return (fd); 5878 } 5879 5880 /* 5881 * Parse a set of command-line arguments. 5882 */ 5883 static int 5884 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5885 const char **argv0, bool *dir_ignore) 5886 { 5887 const char *arg; 5888 char machine[64]; 5889 size_t sz; 5890 int arglen, fd, i, j, mib[2]; 5891 char opt; 5892 bool seen_b, seen_f; 5893 5894 dbg("Parsing command-line arguments"); 5895 *use_pathp = false; 5896 *fdp = -1; 5897 *dir_ignore = false; 5898 seen_b = seen_f = false; 5899 5900 for (i = 1; i < argc; i++ ) { 5901 arg = argv[i]; 5902 dbg("argv[%d]: '%s'", i, arg); 5903 5904 /* 5905 * rtld arguments end with an explicit "--" or with the first 5906 * non-prefixed argument. 5907 */ 5908 if (strcmp(arg, "--") == 0) { 5909 i++; 5910 break; 5911 } 5912 if (arg[0] != '-') 5913 break; 5914 5915 /* 5916 * All other arguments are single-character options that can 5917 * be combined, so we need to search through `arg` for them. 5918 */ 5919 arglen = strlen(arg); 5920 for (j = 1; j < arglen; j++) { 5921 opt = arg[j]; 5922 if (opt == 'h') { 5923 print_usage(argv[0]); 5924 _exit(0); 5925 } else if (opt == 'b') { 5926 if (seen_f) { 5927 _rtld_error("Both -b and -f specified"); 5928 rtld_die(); 5929 } 5930 i++; 5931 *argv0 = argv[i]; 5932 seen_b = true; 5933 break; 5934 } else if (opt == 'd') { 5935 *dir_ignore = true; 5936 break; 5937 } else if (opt == 'f') { 5938 if (seen_b) { 5939 _rtld_error("Both -b and -f specified"); 5940 rtld_die(); 5941 } 5942 5943 /* 5944 * -f XX can be used to specify a 5945 * descriptor for the binary named at 5946 * the command line (i.e., the later 5947 * argument will specify the process 5948 * name but the descriptor is what 5949 * will actually be executed). 5950 * 5951 * -f must be the last option in, e.g., -abcf. 5952 */ 5953 if (j != arglen - 1) { 5954 _rtld_error("Invalid options: %s", arg); 5955 rtld_die(); 5956 } 5957 i++; 5958 fd = parse_integer(argv[i]); 5959 if (fd == -1) { 5960 _rtld_error( 5961 "Invalid file descriptor: '%s'", 5962 argv[i]); 5963 rtld_die(); 5964 } 5965 *fdp = fd; 5966 seen_f = true; 5967 break; 5968 } else if (opt == 'p') { 5969 *use_pathp = true; 5970 } else if (opt == 'u') { 5971 trust = false; 5972 } else if (opt == 'v') { 5973 machine[0] = '\0'; 5974 mib[0] = CTL_HW; 5975 mib[1] = HW_MACHINE; 5976 sz = sizeof(machine); 5977 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5978 ld_elf_hints_path = ld_get_env_var( 5979 LD_ELF_HINTS_PATH); 5980 set_ld_elf_hints_path(); 5981 rtld_printf( 5982 "FreeBSD ld-elf.so.1 %s\n" 5983 "FreeBSD_version %d\n" 5984 "Default lib path %s\n" 5985 "Hints lib path %s\n" 5986 "Env prefix %s\n" 5987 "Default hint file %s\n" 5988 "Hint file %s\n" 5989 "libmap file %s\n", 5990 machine, 5991 __FreeBSD_version, ld_standard_library_path, 5992 gethints(false), 5993 ld_env_prefix, ld_elf_hints_default, 5994 ld_elf_hints_path, 5995 ld_path_libmap_conf); 5996 _exit(0); 5997 } else { 5998 _rtld_error("Invalid argument: '%s'", arg); 5999 print_usage(argv[0]); 6000 rtld_die(); 6001 } 6002 } 6003 } 6004 6005 if (!seen_b) 6006 *argv0 = argv[i]; 6007 return (i); 6008 } 6009 6010 /* 6011 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6012 */ 6013 static int 6014 parse_integer(const char *str) 6015 { 6016 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6017 const char *orig; 6018 int n; 6019 char c; 6020 6021 orig = str; 6022 n = 0; 6023 for (c = *str; c != '\0'; c = *++str) { 6024 if (c < '0' || c > '9') 6025 return (-1); 6026 6027 n *= RADIX; 6028 n += c - '0'; 6029 } 6030 6031 /* Make sure we actually parsed something. */ 6032 if (str == orig) 6033 return (-1); 6034 return (n); 6035 } 6036 6037 static void 6038 print_usage(const char *argv0) 6039 { 6040 6041 rtld_printf( 6042 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6043 "\n" 6044 "Options:\n" 6045 " -h Display this help message\n" 6046 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6047 " -d Ignore lack of exec permissions for the binary\n" 6048 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6049 " -p Search in PATH for named binary\n" 6050 " -u Ignore LD_ environment variables\n" 6051 " -v Display identification information\n" 6052 " -- End of RTLD options\n" 6053 " <binary> Name of process to execute\n" 6054 " <args> Arguments to the executed process\n", argv0); 6055 } 6056 6057 /* 6058 * Overrides for libc_pic-provided functions. 6059 */ 6060 6061 int 6062 __getosreldate(void) 6063 { 6064 size_t len; 6065 int oid[2]; 6066 int error, osrel; 6067 6068 if (osreldate != 0) 6069 return (osreldate); 6070 6071 oid[0] = CTL_KERN; 6072 oid[1] = KERN_OSRELDATE; 6073 osrel = 0; 6074 len = sizeof(osrel); 6075 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6076 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6077 osreldate = osrel; 6078 return (osreldate); 6079 } 6080 const char * 6081 rtld_strerror(int errnum) 6082 { 6083 6084 if (errnum < 0 || errnum >= sys_nerr) 6085 return ("Unknown error"); 6086 return (sys_errlist[errnum]); 6087 } 6088 6089 char * 6090 getenv(const char *name) 6091 { 6092 return (__DECONST(char *, rtld_get_env_val(environ, name, 6093 strlen(name)))); 6094 } 6095 6096 /* malloc */ 6097 void * 6098 malloc(size_t nbytes) 6099 { 6100 6101 return (__crt_malloc(nbytes)); 6102 } 6103 6104 void * 6105 calloc(size_t num, size_t size) 6106 { 6107 6108 return (__crt_calloc(num, size)); 6109 } 6110 6111 void 6112 free(void *cp) 6113 { 6114 6115 __crt_free(cp); 6116 } 6117 6118 void * 6119 realloc(void *cp, size_t nbytes) 6120 { 6121 6122 return (__crt_realloc(cp, nbytes)); 6123 } 6124 6125 extern int _rtld_version__FreeBSD_version __exported; 6126 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6127 6128 extern char _rtld_version_laddr_offset __exported; 6129 char _rtld_version_laddr_offset; 6130 6131 extern char _rtld_version_dlpi_tls_data __exported; 6132 char _rtld_version_dlpi_tls_data; 6133