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 dump_auxv(Elf_Auxinfo **aux_info); 108 static void errmsg_restore(struct dlerror_save *); 109 static struct dlerror_save *errmsg_save(void); 110 static void *fill_search_info(const char *, size_t, void *); 111 static char *find_library(const char *, const Obj_Entry *, int *); 112 static const char *gethints(bool); 113 static void hold_object(Obj_Entry *); 114 static void unhold_object(Obj_Entry *); 115 static void init_dag(Obj_Entry *); 116 static void init_marker(Obj_Entry *); 117 static void init_pagesizes(Elf_Auxinfo **aux_info); 118 static void init_rtld(caddr_t, Elf_Auxinfo **); 119 static void initlist_add_neededs(Needed_Entry *, Objlist *); 120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 122 static void linkmap_add(Obj_Entry *); 123 static void linkmap_delete(Obj_Entry *); 124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 125 static void unload_filtees(Obj_Entry *, RtldLockState *); 126 static int load_needed_objects(Obj_Entry *, int); 127 static int load_preload_objects(const char *, bool); 128 static int load_kpreload(const void *addr); 129 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 130 static void map_stacks_exec(RtldLockState *); 131 static int obj_disable_relro(Obj_Entry *); 132 static int obj_enforce_relro(Obj_Entry *); 133 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 134 static void objlist_call_init(Objlist *, RtldLockState *); 135 static void objlist_clear(Objlist *); 136 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 137 static void objlist_init(Objlist *); 138 static void objlist_push_head(Objlist *, Obj_Entry *); 139 static void objlist_push_tail(Objlist *, Obj_Entry *); 140 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 141 static void objlist_remove(Objlist *, Obj_Entry *); 142 static int open_binary_fd(const char *argv0, bool search_in_path, 143 const char **binpath_res); 144 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 145 const char **argv0, bool *dir_ignore); 146 static int parse_integer(const char *); 147 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 148 static void print_usage(const char *argv0); 149 static void release_object(Obj_Entry *); 150 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 151 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 152 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 153 int flags, RtldLockState *lockstate); 154 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 155 RtldLockState *); 156 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 157 static int rtld_dirname(const char *, char *); 158 static int rtld_dirname_abs(const char *, char *); 159 static void *rtld_dlopen(const char *name, int fd, int mode); 160 static void rtld_exit(void); 161 static void rtld_nop_exit(void); 162 static char *search_library_path(const char *, const char *, const char *, 163 int *); 164 static char *search_library_pathfds(const char *, const char *, int *); 165 static const void **get_program_var_addr(const char *, RtldLockState *); 166 static void set_program_var(const char *, const void *); 167 static int symlook_default(SymLook *, const Obj_Entry *refobj); 168 static int symlook_global(SymLook *, DoneList *); 169 static void symlook_init_from_req(SymLook *, const SymLook *); 170 static int symlook_list(SymLook *, const Objlist *, DoneList *); 171 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 172 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 173 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 174 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 175 static void trace_loaded_objects(Obj_Entry *); 176 static void unlink_object(Obj_Entry *); 177 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 178 static void unref_dag(Obj_Entry *); 179 static void ref_dag(Obj_Entry *); 180 static char *origin_subst_one(Obj_Entry *, char *, const char *, 181 const char *, bool); 182 static char *origin_subst(Obj_Entry *, const char *); 183 static bool obj_resolve_origin(Obj_Entry *obj); 184 static void preinit_main(void); 185 static int rtld_verify_versions(const Objlist *); 186 static int rtld_verify_object_versions(Obj_Entry *); 187 static void object_add_name(Obj_Entry *, const char *); 188 static int object_match_name(const Obj_Entry *, const char *); 189 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 190 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 191 struct dl_phdr_info *phdr_info); 192 static uint32_t gnu_hash(const char *); 193 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 194 const unsigned long); 195 196 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 197 void _r_debug_postinit(struct link_map *) __noinline __exported; 198 199 int __sys_openat(int, const char *, int, ...); 200 201 /* 202 * Data declarations. 203 */ 204 struct r_debug r_debug __exported; /* for GDB; */ 205 static bool libmap_disable; /* Disable libmap */ 206 static bool ld_loadfltr; /* Immediate filters processing */ 207 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 208 static bool trust; /* False for setuid and setgid programs */ 209 static bool dangerous_ld_env; /* True if environment variables have been 210 used to affect the libraries loaded */ 211 bool ld_bind_not; /* Disable PLT update */ 212 static const char *ld_bind_now; /* Environment variable for immediate binding */ 213 static const char *ld_debug; /* Environment variable for debugging */ 214 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 215 weak definition */ 216 static const char *ld_library_path;/* Environment variable for search path */ 217 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 218 static const char *ld_preload; /* Environment variable for libraries to 219 load first */ 220 static const char *ld_preload_fds;/* Environment variable for libraries represented by 221 descriptors */ 222 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 223 static const char *ld_tracing; /* Called from ldd to print libs */ 224 static const char *ld_utrace; /* Use utrace() to log events. */ 225 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 226 static Obj_Entry *obj_main; /* The main program shared object */ 227 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 228 static unsigned int obj_count; /* Number of objects in obj_list */ 229 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 268 int npagesizes; 269 static int osreldate; 270 size_t *pagesizes; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 enum { 348 LD_BIND_NOW = 0, 349 LD_PRELOAD, 350 LD_LIBMAP, 351 LD_LIBRARY_PATH, 352 LD_LIBRARY_PATH_FDS, 353 LD_LIBMAP_DISABLE, 354 LD_BIND_NOT, 355 LD_DEBUG, 356 LD_ELF_HINTS_PATH, 357 LD_LOADFLTR, 358 LD_LIBRARY_PATH_RPATH, 359 LD_PRELOAD_FDS, 360 LD_DYNAMIC_WEAK, 361 LD_TRACE_LOADED_OBJECTS, 362 LD_UTRACE, 363 LD_DUMP_REL_PRE, 364 LD_DUMP_REL_POST, 365 LD_TRACE_LOADED_OBJECTS_PROGNAME, 366 LD_TRACE_LOADED_OBJECTS_FMT1, 367 LD_TRACE_LOADED_OBJECTS_FMT2, 368 LD_TRACE_LOADED_OBJECTS_ALL, 369 LD_SHOW_AUXV, 370 }; 371 372 struct ld_env_var_desc { 373 const char * const n; 374 const char *val; 375 const bool unsecure; 376 }; 377 #define LD_ENV_DESC(var, unsec) \ 378 [LD_##var] = { .n = #var, .unsecure = unsec } 379 380 static struct ld_env_var_desc ld_env_vars[] = { 381 LD_ENV_DESC(BIND_NOW, false), 382 LD_ENV_DESC(PRELOAD, true), 383 LD_ENV_DESC(LIBMAP, true), 384 LD_ENV_DESC(LIBRARY_PATH, true), 385 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 386 LD_ENV_DESC(LIBMAP_DISABLE, true), 387 LD_ENV_DESC(BIND_NOT, true), 388 LD_ENV_DESC(DEBUG, true), 389 LD_ENV_DESC(ELF_HINTS_PATH, true), 390 LD_ENV_DESC(LOADFLTR, true), 391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 392 LD_ENV_DESC(PRELOAD_FDS, true), 393 LD_ENV_DESC(DYNAMIC_WEAK, true), 394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 395 LD_ENV_DESC(UTRACE, false), 396 LD_ENV_DESC(DUMP_REL_PRE, false), 397 LD_ENV_DESC(DUMP_REL_POST, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 402 LD_ENV_DESC(SHOW_AUXV, false), 403 }; 404 405 static const char * 406 ld_get_env_var(int idx) 407 { 408 return (ld_env_vars[idx].val); 409 } 410 411 static const char * 412 rtld_get_env_val(char **env, const char *name, size_t name_len) 413 { 414 char **m, *n, *v; 415 416 for (m = env; *m != NULL; m++) { 417 n = *m; 418 v = strchr(n, '='); 419 if (v == NULL) { 420 /* corrupt environment? */ 421 continue; 422 } 423 if (v - n == (ptrdiff_t)name_len && 424 strncmp(name, n, name_len) == 0) 425 return (v + 1); 426 } 427 return (NULL); 428 } 429 430 static void 431 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 432 { 433 struct ld_env_var_desc *lvd; 434 size_t prefix_len, nlen; 435 char **m, *n, *v; 436 int i; 437 438 prefix_len = strlen(env_prefix); 439 for (m = env; *m != NULL; m++) { 440 n = *m; 441 if (strncmp(env_prefix, n, prefix_len) != 0) { 442 /* Not a rtld environment variable. */ 443 continue; 444 } 445 n += prefix_len; 446 v = strchr(n, '='); 447 if (v == NULL) { 448 /* corrupt environment? */ 449 continue; 450 } 451 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 452 lvd = &ld_env_vars[i]; 453 if (lvd->val != NULL) { 454 /* Saw higher-priority variable name already. */ 455 continue; 456 } 457 nlen = strlen(lvd->n); 458 if (v - n == (ptrdiff_t)nlen && 459 strncmp(lvd->n, n, nlen) == 0) { 460 lvd->val = v + 1; 461 break; 462 } 463 } 464 } 465 } 466 467 static void 468 rtld_init_env_vars(char **env) 469 { 470 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 471 } 472 473 static void 474 set_ld_elf_hints_path(void) 475 { 476 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 477 ld_elf_hints_path = ld_elf_hints_default; 478 } 479 480 /* 481 * Main entry point for dynamic linking. The first argument is the 482 * stack pointer. The stack is expected to be laid out as described 483 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 484 * Specifically, the stack pointer points to a word containing 485 * ARGC. Following that in the stack is a null-terminated sequence 486 * of pointers to argument strings. Then comes a null-terminated 487 * sequence of pointers to environment strings. Finally, there is a 488 * sequence of "auxiliary vector" entries. 489 * 490 * The second argument points to a place to store the dynamic linker's 491 * exit procedure pointer and the third to a place to store the main 492 * program's object. 493 * 494 * The return value is the main program's entry point. 495 */ 496 func_ptr_type 497 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 498 { 499 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 500 Objlist_Entry *entry; 501 Obj_Entry *last_interposer, *obj, *preload_tail; 502 const Elf_Phdr *phdr; 503 Objlist initlist; 504 RtldLockState lockstate; 505 struct stat st; 506 Elf_Addr *argcp; 507 char **argv, **env, **envp, *kexecpath; 508 const char *argv0, *binpath, *library_path_rpath; 509 struct ld_env_var_desc *lvd; 510 caddr_t imgentry; 511 char buf[MAXPATHLEN]; 512 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 513 size_t sz; 514 #ifdef __powerpc__ 515 int old_auxv_format = 1; 516 #endif 517 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 518 519 /* 520 * On entry, the dynamic linker itself has not been relocated yet. 521 * Be very careful not to reference any global data until after 522 * init_rtld has returned. It is OK to reference file-scope statics 523 * and string constants, and to call static and global functions. 524 */ 525 526 /* Find the auxiliary vector on the stack. */ 527 argcp = sp; 528 argc = *sp++; 529 argv = (char **) sp; 530 sp += argc + 1; /* Skip over arguments and NULL terminator */ 531 env = (char **) sp; 532 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 533 ; 534 aux = (Elf_Auxinfo *) sp; 535 536 /* Digest the auxiliary vector. */ 537 for (i = 0; i < AT_COUNT; i++) 538 aux_info[i] = NULL; 539 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 540 if (auxp->a_type < AT_COUNT) 541 aux_info[auxp->a_type] = auxp; 542 #ifdef __powerpc__ 543 if (auxp->a_type == 23) /* AT_STACKPROT */ 544 old_auxv_format = 0; 545 #endif 546 } 547 548 #ifdef __powerpc__ 549 if (old_auxv_format) { 550 /* Remap from old-style auxv numbers. */ 551 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 552 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 553 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 554 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 555 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 556 aux_info[13] = NULL; /* AT_GID */ 557 558 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 559 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 560 aux_info[16] = aux_info[14]; /* AT_CANARY */ 561 aux_info[14] = NULL; /* AT_EGID */ 562 } 563 #endif 564 565 /* Initialize and relocate ourselves. */ 566 assert(aux_info[AT_BASE] != NULL); 567 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 568 569 dlerror_dflt_init(); 570 571 __progname = obj_rtld.path; 572 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 573 environ = env; 574 main_argc = argc; 575 main_argv = argv; 576 577 if (aux_info[AT_BSDFLAGS] != NULL && 578 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 579 ld_fast_sigblock = true; 580 581 trust = !issetugid(); 582 direct_exec = false; 583 584 md_abi_variant_hook(aux_info); 585 rtld_init_env_vars(env); 586 587 fd = -1; 588 if (aux_info[AT_EXECFD] != NULL) { 589 fd = aux_info[AT_EXECFD]->a_un.a_val; 590 } else { 591 assert(aux_info[AT_PHDR] != NULL); 592 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 593 if (phdr == obj_rtld.phdr) { 594 if (!trust) { 595 _rtld_error("Tainted process refusing to run binary %s", 596 argv0); 597 rtld_die(); 598 } 599 direct_exec = true; 600 601 dbg("opening main program in direct exec mode"); 602 if (argc >= 2) { 603 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 604 &argv0, &dir_ignore); 605 explicit_fd = (fd != -1); 606 binpath = NULL; 607 if (!explicit_fd) 608 fd = open_binary_fd(argv0, search_in_path, &binpath); 609 if (fstat(fd, &st) == -1) { 610 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 611 explicit_fd ? "user-provided descriptor" : argv0, 612 rtld_strerror(errno)); 613 rtld_die(); 614 } 615 616 /* 617 * Rough emulation of the permission checks done by 618 * execve(2), only Unix DACs are checked, ACLs are 619 * ignored. Preserve the semantic of disabling owner 620 * to execute if owner x bit is cleared, even if 621 * others x bit is enabled. 622 * mmap(2) does not allow to mmap with PROT_EXEC if 623 * binary' file comes from noexec mount. We cannot 624 * set a text reference on the binary. 625 */ 626 dir_enable = false; 627 if (st.st_uid == geteuid()) { 628 if ((st.st_mode & S_IXUSR) != 0) 629 dir_enable = true; 630 } else if (st.st_gid == getegid()) { 631 if ((st.st_mode & S_IXGRP) != 0) 632 dir_enable = true; 633 } else if ((st.st_mode & S_IXOTH) != 0) { 634 dir_enable = true; 635 } 636 if (!dir_enable && !dir_ignore) { 637 _rtld_error("No execute permission for binary %s", 638 argv0); 639 rtld_die(); 640 } 641 642 /* 643 * For direct exec mode, argv[0] is the interpreter 644 * name, we must remove it and shift arguments left 645 * before invoking binary main. Since stack layout 646 * places environment pointers and aux vectors right 647 * after the terminating NULL, we must shift 648 * environment and aux as well. 649 */ 650 main_argc = argc - rtld_argc; 651 for (i = 0; i <= main_argc; i++) 652 argv[i] = argv[i + rtld_argc]; 653 *argcp -= rtld_argc; 654 environ = env = envp = argv + main_argc + 1; 655 dbg("move env from %p to %p", envp + rtld_argc, envp); 656 do { 657 *envp = *(envp + rtld_argc); 658 } while (*envp++ != NULL); 659 aux = auxp = (Elf_Auxinfo *)envp; 660 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 661 dbg("move aux from %p to %p", auxpf, aux); 662 /* XXXKIB insert place for AT_EXECPATH if not present */ 663 for (;; auxp++, auxpf++) { 664 *auxp = *auxpf; 665 if (auxp->a_type == AT_NULL) 666 break; 667 } 668 /* Since the auxiliary vector has moved, redigest it. */ 669 for (i = 0; i < AT_COUNT; i++) 670 aux_info[i] = NULL; 671 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 672 if (auxp->a_type < AT_COUNT) 673 aux_info[auxp->a_type] = auxp; 674 } 675 676 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 677 if (binpath == NULL) { 678 aux_info[AT_EXECPATH] = NULL; 679 } else { 680 if (aux_info[AT_EXECPATH] == NULL) { 681 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 682 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 683 } 684 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 685 binpath); 686 } 687 } else { 688 _rtld_error("No binary"); 689 rtld_die(); 690 } 691 } 692 } 693 694 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 695 696 /* 697 * If the process is tainted, then we un-set the dangerous environment 698 * variables. The process will be marked as tainted until setuid(2) 699 * is called. If any child process calls setuid(2) we do not want any 700 * future processes to honor the potentially un-safe variables. 701 */ 702 if (!trust) { 703 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 704 lvd = &ld_env_vars[i]; 705 if (lvd->unsecure) 706 lvd->val = NULL; 707 } 708 } 709 710 ld_debug = ld_get_env_var(LD_DEBUG); 711 if (ld_bind_now == NULL) 712 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 713 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 714 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 715 libmap_override = ld_get_env_var(LD_LIBMAP); 716 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 717 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 718 ld_preload = ld_get_env_var(LD_PRELOAD); 719 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 720 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 721 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 722 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 723 if (library_path_rpath != NULL) { 724 if (library_path_rpath[0] == 'y' || 725 library_path_rpath[0] == 'Y' || 726 library_path_rpath[0] == '1') 727 ld_library_path_rpath = true; 728 else 729 ld_library_path_rpath = false; 730 } 731 dangerous_ld_env = libmap_disable || libmap_override != NULL || 732 ld_library_path != NULL || ld_preload != NULL || 733 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 734 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 735 ld_utrace = ld_get_env_var(LD_UTRACE); 736 737 set_ld_elf_hints_path(); 738 if (ld_debug != NULL && *ld_debug != '\0') 739 debug = 1; 740 dbg("%s is initialized, base address = %p", __progname, 741 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 742 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 743 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 744 745 dbg("initializing thread locks"); 746 lockdflt_init(); 747 748 /* 749 * Load the main program, or process its program header if it is 750 * already loaded. 751 */ 752 if (fd != -1) { /* Load the main program. */ 753 dbg("loading main program"); 754 obj_main = map_object(fd, argv0, NULL); 755 close(fd); 756 if (obj_main == NULL) 757 rtld_die(); 758 max_stack_flags = obj_main->stack_flags; 759 } else { /* Main program already loaded. */ 760 dbg("processing main program's program header"); 761 assert(aux_info[AT_PHDR] != NULL); 762 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 763 assert(aux_info[AT_PHNUM] != NULL); 764 phnum = aux_info[AT_PHNUM]->a_un.a_val; 765 assert(aux_info[AT_PHENT] != NULL); 766 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 767 assert(aux_info[AT_ENTRY] != NULL); 768 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 769 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 770 rtld_die(); 771 } 772 773 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 774 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 775 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 776 if (kexecpath[0] == '/') 777 obj_main->path = kexecpath; 778 else if (getcwd(buf, sizeof(buf)) == NULL || 779 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 780 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 781 obj_main->path = xstrdup(argv0); 782 else 783 obj_main->path = xstrdup(buf); 784 } else { 785 dbg("No AT_EXECPATH or direct exec"); 786 obj_main->path = xstrdup(argv0); 787 } 788 dbg("obj_main path %s", obj_main->path); 789 obj_main->mainprog = true; 790 791 if (aux_info[AT_STACKPROT] != NULL && 792 aux_info[AT_STACKPROT]->a_un.a_val != 0) 793 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 794 795 #ifndef COMPAT_32BIT 796 /* 797 * Get the actual dynamic linker pathname from the executable if 798 * possible. (It should always be possible.) That ensures that 799 * gdb will find the right dynamic linker even if a non-standard 800 * one is being used. 801 */ 802 if (obj_main->interp != NULL && 803 strcmp(obj_main->interp, obj_rtld.path) != 0) { 804 free(obj_rtld.path); 805 obj_rtld.path = xstrdup(obj_main->interp); 806 __progname = obj_rtld.path; 807 } 808 #endif 809 810 if (!digest_dynamic(obj_main, 0)) 811 rtld_die(); 812 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 813 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 814 obj_main->dynsymcount); 815 816 linkmap_add(obj_main); 817 linkmap_add(&obj_rtld); 818 819 /* Link the main program into the list of objects. */ 820 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 821 obj_count++; 822 obj_loads++; 823 824 /* Initialize a fake symbol for resolving undefined weak references. */ 825 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 826 sym_zero.st_shndx = SHN_UNDEF; 827 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 828 829 if (!libmap_disable) 830 libmap_disable = (bool)lm_init(libmap_override); 831 832 if (aux_info[AT_KPRELOAD] != NULL && 833 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 834 dbg("loading kernel vdso"); 835 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 836 rtld_die(); 837 } 838 839 dbg("loading LD_PRELOAD_FDS libraries"); 840 if (load_preload_objects(ld_preload_fds, true) == -1) 841 rtld_die(); 842 843 dbg("loading LD_PRELOAD libraries"); 844 if (load_preload_objects(ld_preload, false) == -1) 845 rtld_die(); 846 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 847 848 dbg("loading needed objects"); 849 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 850 0) == -1) 851 rtld_die(); 852 853 /* Make a list of all objects loaded at startup. */ 854 last_interposer = obj_main; 855 TAILQ_FOREACH(obj, &obj_list, next) { 856 if (obj->marker) 857 continue; 858 if (obj->z_interpose && obj != obj_main) { 859 objlist_put_after(&list_main, last_interposer, obj); 860 last_interposer = obj; 861 } else { 862 objlist_push_tail(&list_main, obj); 863 } 864 obj->refcount++; 865 } 866 867 dbg("checking for required versions"); 868 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 869 rtld_die(); 870 871 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 872 dump_auxv(aux_info); 873 874 if (ld_tracing) { /* We're done */ 875 trace_loaded_objects(obj_main); 876 exit(0); 877 } 878 879 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 880 dump_relocations(obj_main); 881 exit (0); 882 } 883 884 /* 885 * Processing tls relocations requires having the tls offsets 886 * initialized. Prepare offsets before starting initial 887 * relocation processing. 888 */ 889 dbg("initializing initial thread local storage offsets"); 890 STAILQ_FOREACH(entry, &list_main, link) { 891 /* 892 * Allocate all the initial objects out of the static TLS 893 * block even if they didn't ask for it. 894 */ 895 allocate_tls_offset(entry->obj); 896 } 897 898 if (relocate_objects(obj_main, 899 ld_bind_now != NULL && *ld_bind_now != '\0', 900 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 901 rtld_die(); 902 903 dbg("doing copy relocations"); 904 if (do_copy_relocations(obj_main) == -1) 905 rtld_die(); 906 907 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 908 dump_relocations(obj_main); 909 exit (0); 910 } 911 912 ifunc_init(aux); 913 914 /* 915 * Setup TLS for main thread. This must be done after the 916 * relocations are processed, since tls initialization section 917 * might be the subject for relocations. 918 */ 919 dbg("initializing initial thread local storage"); 920 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 921 922 dbg("initializing key program variables"); 923 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 924 set_program_var("environ", env); 925 set_program_var("__elf_aux_vector", aux); 926 927 /* Make a list of init functions to call. */ 928 objlist_init(&initlist); 929 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 930 preload_tail, &initlist); 931 932 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 933 934 map_stacks_exec(NULL); 935 936 if (!obj_main->crt_no_init) { 937 /* 938 * Make sure we don't call the main program's init and fini 939 * functions for binaries linked with old crt1 which calls 940 * _init itself. 941 */ 942 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 943 obj_main->preinit_array = obj_main->init_array = 944 obj_main->fini_array = (Elf_Addr)NULL; 945 } 946 947 if (direct_exec) { 948 /* Set osrel for direct-execed binary */ 949 mib[0] = CTL_KERN; 950 mib[1] = KERN_PROC; 951 mib[2] = KERN_PROC_OSREL; 952 mib[3] = getpid(); 953 osrel = obj_main->osrel; 954 sz = sizeof(old_osrel); 955 dbg("setting osrel to %d", osrel); 956 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 957 } 958 959 wlock_acquire(rtld_bind_lock, &lockstate); 960 961 dbg("resolving ifuncs"); 962 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 963 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 964 rtld_die(); 965 966 rtld_exit_ptr = rtld_exit; 967 if (obj_main->crt_no_init) 968 preinit_main(); 969 objlist_call_init(&initlist, &lockstate); 970 _r_debug_postinit(&obj_main->linkmap); 971 objlist_clear(&initlist); 972 dbg("loading filtees"); 973 TAILQ_FOREACH(obj, &obj_list, next) { 974 if (obj->marker) 975 continue; 976 if (ld_loadfltr || obj->z_loadfltr) 977 load_filtees(obj, 0, &lockstate); 978 } 979 980 dbg("enforcing main obj relro"); 981 if (obj_enforce_relro(obj_main) == -1) 982 rtld_die(); 983 984 lock_release(rtld_bind_lock, &lockstate); 985 986 dbg("transferring control to program entry point = %p", obj_main->entry); 987 988 /* Return the exit procedure and the program entry point. */ 989 *exit_proc = rtld_exit_ptr; 990 *objp = obj_main; 991 return ((func_ptr_type)obj_main->entry); 992 } 993 994 void * 995 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 996 { 997 void *ptr; 998 Elf_Addr target; 999 1000 ptr = (void *)make_function_pointer(def, obj); 1001 target = call_ifunc_resolver(ptr); 1002 return ((void *)target); 1003 } 1004 1005 /* 1006 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 1007 * Changes to this function should be applied there as well. 1008 */ 1009 Elf_Addr 1010 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1011 { 1012 const Elf_Rel *rel; 1013 const Elf_Sym *def; 1014 const Obj_Entry *defobj; 1015 Elf_Addr *where; 1016 Elf_Addr target; 1017 RtldLockState lockstate; 1018 1019 rlock_acquire(rtld_bind_lock, &lockstate); 1020 if (sigsetjmp(lockstate.env, 0) != 0) 1021 lock_upgrade(rtld_bind_lock, &lockstate); 1022 if (obj->pltrel) 1023 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1024 else 1025 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1026 1027 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1028 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1029 NULL, &lockstate); 1030 if (def == NULL) 1031 rtld_die(); 1032 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1033 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1034 else 1035 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1036 1037 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1038 defobj->strtab + def->st_name, 1039 obj->path == NULL ? NULL : basename(obj->path), 1040 (void *)target, 1041 defobj->path == NULL ? NULL : basename(defobj->path)); 1042 1043 /* 1044 * Write the new contents for the jmpslot. Note that depending on 1045 * architecture, the value which we need to return back to the 1046 * lazy binding trampoline may or may not be the target 1047 * address. The value returned from reloc_jmpslot() is the value 1048 * that the trampoline needs. 1049 */ 1050 target = reloc_jmpslot(where, target, defobj, obj, rel); 1051 lock_release(rtld_bind_lock, &lockstate); 1052 return (target); 1053 } 1054 1055 /* 1056 * Error reporting function. Use it like printf. If formats the message 1057 * into a buffer, and sets things up so that the next call to dlerror() 1058 * will return the message. 1059 */ 1060 void 1061 _rtld_error(const char *fmt, ...) 1062 { 1063 va_list ap; 1064 1065 va_start(ap, fmt); 1066 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1067 fmt, ap); 1068 va_end(ap); 1069 *lockinfo.dlerror_seen() = 0; 1070 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1071 } 1072 1073 /* 1074 * Return a dynamically-allocated copy of the current error message, if any. 1075 */ 1076 static struct dlerror_save * 1077 errmsg_save(void) 1078 { 1079 struct dlerror_save *res; 1080 1081 res = xmalloc(sizeof(*res)); 1082 res->seen = *lockinfo.dlerror_seen(); 1083 if (res->seen == 0) 1084 res->msg = xstrdup(lockinfo.dlerror_loc()); 1085 return (res); 1086 } 1087 1088 /* 1089 * Restore the current error message from a copy which was previously saved 1090 * by errmsg_save(). The copy is freed. 1091 */ 1092 static void 1093 errmsg_restore(struct dlerror_save *saved_msg) 1094 { 1095 if (saved_msg == NULL || saved_msg->seen == 1) { 1096 *lockinfo.dlerror_seen() = 1; 1097 } else { 1098 *lockinfo.dlerror_seen() = 0; 1099 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1100 lockinfo.dlerror_loc_sz); 1101 free(saved_msg->msg); 1102 } 1103 free(saved_msg); 1104 } 1105 1106 static const char * 1107 basename(const char *name) 1108 { 1109 const char *p; 1110 1111 p = strrchr(name, '/'); 1112 return (p != NULL ? p + 1 : name); 1113 } 1114 1115 static struct utsname uts; 1116 1117 static char * 1118 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1119 const char *subst, bool may_free) 1120 { 1121 char *p, *p1, *res, *resp; 1122 int subst_len, kw_len, subst_count, old_len, new_len; 1123 1124 kw_len = strlen(kw); 1125 1126 /* 1127 * First, count the number of the keyword occurrences, to 1128 * preallocate the final string. 1129 */ 1130 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1131 p1 = strstr(p, kw); 1132 if (p1 == NULL) 1133 break; 1134 } 1135 1136 /* 1137 * If the keyword is not found, just return. 1138 * 1139 * Return non-substituted string if resolution failed. We 1140 * cannot do anything more reasonable, the failure mode of the 1141 * caller is unresolved library anyway. 1142 */ 1143 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1144 return (may_free ? real : xstrdup(real)); 1145 if (obj != NULL) 1146 subst = obj->origin_path; 1147 1148 /* 1149 * There is indeed something to substitute. Calculate the 1150 * length of the resulting string, and allocate it. 1151 */ 1152 subst_len = strlen(subst); 1153 old_len = strlen(real); 1154 new_len = old_len + (subst_len - kw_len) * subst_count; 1155 res = xmalloc(new_len + 1); 1156 1157 /* 1158 * Now, execute the substitution loop. 1159 */ 1160 for (p = real, resp = res, *resp = '\0';;) { 1161 p1 = strstr(p, kw); 1162 if (p1 != NULL) { 1163 /* Copy the prefix before keyword. */ 1164 memcpy(resp, p, p1 - p); 1165 resp += p1 - p; 1166 /* Keyword replacement. */ 1167 memcpy(resp, subst, subst_len); 1168 resp += subst_len; 1169 *resp = '\0'; 1170 p = p1 + kw_len; 1171 } else 1172 break; 1173 } 1174 1175 /* Copy to the end of string and finish. */ 1176 strcat(resp, p); 1177 if (may_free) 1178 free(real); 1179 return (res); 1180 } 1181 1182 static const struct { 1183 const char *kw; 1184 bool pass_obj; 1185 const char *subst; 1186 } tokens[] = { 1187 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1188 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1189 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1190 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1191 }; 1192 1193 static char * 1194 origin_subst(Obj_Entry *obj, const char *real) 1195 { 1196 char *res; 1197 int i; 1198 1199 if (obj == NULL || !trust) 1200 return (xstrdup(real)); 1201 if (uts.sysname[0] == '\0') { 1202 if (uname(&uts) != 0) { 1203 _rtld_error("utsname failed: %d", errno); 1204 return (NULL); 1205 } 1206 } 1207 1208 /* __DECONST is safe here since without may_free real is unchanged */ 1209 res = __DECONST(char *, real); 1210 for (i = 0; i < (int)nitems(tokens); i++) { 1211 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1212 res, tokens[i].kw, tokens[i].subst, i == 0); 1213 } 1214 return (res); 1215 } 1216 1217 void 1218 rtld_die(void) 1219 { 1220 const char *msg = dlerror(); 1221 1222 if (msg == NULL) 1223 msg = "Fatal error"; 1224 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1225 rtld_fdputstr(STDERR_FILENO, msg); 1226 rtld_fdputchar(STDERR_FILENO, '\n'); 1227 _exit(1); 1228 } 1229 1230 /* 1231 * Process a shared object's DYNAMIC section, and save the important 1232 * information in its Obj_Entry structure. 1233 */ 1234 static void 1235 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1236 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1237 { 1238 const Elf_Dyn *dynp; 1239 Needed_Entry **needed_tail = &obj->needed; 1240 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1241 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1242 const Elf_Hashelt *hashtab; 1243 const Elf32_Word *hashval; 1244 Elf32_Word bkt, nmaskwords; 1245 int bloom_size32; 1246 int plttype = DT_REL; 1247 1248 *dyn_rpath = NULL; 1249 *dyn_soname = NULL; 1250 *dyn_runpath = NULL; 1251 1252 obj->bind_now = false; 1253 dynp = obj->dynamic; 1254 if (dynp == NULL) 1255 return; 1256 for (; dynp->d_tag != DT_NULL; dynp++) { 1257 switch (dynp->d_tag) { 1258 1259 case DT_REL: 1260 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1261 break; 1262 1263 case DT_RELSZ: 1264 obj->relsize = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_RELENT: 1268 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1269 break; 1270 1271 case DT_JMPREL: 1272 obj->pltrel = (const Elf_Rel *) 1273 (obj->relocbase + dynp->d_un.d_ptr); 1274 break; 1275 1276 case DT_PLTRELSZ: 1277 obj->pltrelsize = dynp->d_un.d_val; 1278 break; 1279 1280 case DT_RELA: 1281 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_RELASZ: 1285 obj->relasize = dynp->d_un.d_val; 1286 break; 1287 1288 case DT_RELAENT: 1289 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1290 break; 1291 1292 case DT_RELR: 1293 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1294 break; 1295 1296 case DT_RELRSZ: 1297 obj->relrsize = dynp->d_un.d_val; 1298 break; 1299 1300 case DT_RELRENT: 1301 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1302 break; 1303 1304 case DT_PLTREL: 1305 plttype = dynp->d_un.d_val; 1306 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1307 break; 1308 1309 case DT_SYMTAB: 1310 obj->symtab = (const Elf_Sym *) 1311 (obj->relocbase + dynp->d_un.d_ptr); 1312 break; 1313 1314 case DT_SYMENT: 1315 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1316 break; 1317 1318 case DT_STRTAB: 1319 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1320 break; 1321 1322 case DT_STRSZ: 1323 obj->strsize = dynp->d_un.d_val; 1324 break; 1325 1326 case DT_VERNEED: 1327 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1328 dynp->d_un.d_val); 1329 break; 1330 1331 case DT_VERNEEDNUM: 1332 obj->verneednum = dynp->d_un.d_val; 1333 break; 1334 1335 case DT_VERDEF: 1336 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1337 dynp->d_un.d_val); 1338 break; 1339 1340 case DT_VERDEFNUM: 1341 obj->verdefnum = dynp->d_un.d_val; 1342 break; 1343 1344 case DT_VERSYM: 1345 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1346 dynp->d_un.d_val); 1347 break; 1348 1349 case DT_HASH: 1350 { 1351 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1352 dynp->d_un.d_ptr); 1353 obj->nbuckets = hashtab[0]; 1354 obj->nchains = hashtab[1]; 1355 obj->buckets = hashtab + 2; 1356 obj->chains = obj->buckets + obj->nbuckets; 1357 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1358 obj->buckets != NULL; 1359 } 1360 break; 1361 1362 case DT_GNU_HASH: 1363 { 1364 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1365 dynp->d_un.d_ptr); 1366 obj->nbuckets_gnu = hashtab[0]; 1367 obj->symndx_gnu = hashtab[1]; 1368 nmaskwords = hashtab[2]; 1369 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1370 obj->maskwords_bm_gnu = nmaskwords - 1; 1371 obj->shift2_gnu = hashtab[3]; 1372 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1373 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1374 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1375 obj->symndx_gnu; 1376 /* Number of bitmask words is required to be power of 2 */ 1377 obj->valid_hash_gnu = powerof2(nmaskwords) && 1378 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1379 } 1380 break; 1381 1382 case DT_NEEDED: 1383 if (!obj->rtld) { 1384 Needed_Entry *nep = NEW(Needed_Entry); 1385 nep->name = dynp->d_un.d_val; 1386 nep->obj = NULL; 1387 nep->next = NULL; 1388 1389 *needed_tail = nep; 1390 needed_tail = &nep->next; 1391 } 1392 break; 1393 1394 case DT_FILTER: 1395 if (!obj->rtld) { 1396 Needed_Entry *nep = NEW(Needed_Entry); 1397 nep->name = dynp->d_un.d_val; 1398 nep->obj = NULL; 1399 nep->next = NULL; 1400 1401 *needed_filtees_tail = nep; 1402 needed_filtees_tail = &nep->next; 1403 1404 if (obj->linkmap.l_refname == NULL) 1405 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1406 } 1407 break; 1408 1409 case DT_AUXILIARY: 1410 if (!obj->rtld) { 1411 Needed_Entry *nep = NEW(Needed_Entry); 1412 nep->name = dynp->d_un.d_val; 1413 nep->obj = NULL; 1414 nep->next = NULL; 1415 1416 *needed_aux_filtees_tail = nep; 1417 needed_aux_filtees_tail = &nep->next; 1418 } 1419 break; 1420 1421 case DT_PLTGOT: 1422 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1423 break; 1424 1425 case DT_TEXTREL: 1426 obj->textrel = true; 1427 break; 1428 1429 case DT_SYMBOLIC: 1430 obj->symbolic = true; 1431 break; 1432 1433 case DT_RPATH: 1434 /* 1435 * We have to wait until later to process this, because we 1436 * might not have gotten the address of the string table yet. 1437 */ 1438 *dyn_rpath = dynp; 1439 break; 1440 1441 case DT_SONAME: 1442 *dyn_soname = dynp; 1443 break; 1444 1445 case DT_RUNPATH: 1446 *dyn_runpath = dynp; 1447 break; 1448 1449 case DT_INIT: 1450 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1451 break; 1452 1453 case DT_PREINIT_ARRAY: 1454 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1455 break; 1456 1457 case DT_PREINIT_ARRAYSZ: 1458 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1459 break; 1460 1461 case DT_INIT_ARRAY: 1462 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1463 break; 1464 1465 case DT_INIT_ARRAYSZ: 1466 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1467 break; 1468 1469 case DT_FINI: 1470 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1471 break; 1472 1473 case DT_FINI_ARRAY: 1474 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1475 break; 1476 1477 case DT_FINI_ARRAYSZ: 1478 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1479 break; 1480 1481 /* 1482 * Don't process DT_DEBUG on MIPS as the dynamic section 1483 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1484 */ 1485 1486 #ifndef __mips__ 1487 case DT_DEBUG: 1488 if (!early) 1489 dbg("Filling in DT_DEBUG entry"); 1490 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1491 break; 1492 #endif 1493 1494 case DT_FLAGS: 1495 if (dynp->d_un.d_val & DF_ORIGIN) 1496 obj->z_origin = true; 1497 if (dynp->d_un.d_val & DF_SYMBOLIC) 1498 obj->symbolic = true; 1499 if (dynp->d_un.d_val & DF_TEXTREL) 1500 obj->textrel = true; 1501 if (dynp->d_un.d_val & DF_BIND_NOW) 1502 obj->bind_now = true; 1503 if (dynp->d_un.d_val & DF_STATIC_TLS) 1504 obj->static_tls = true; 1505 break; 1506 #ifdef __mips__ 1507 case DT_MIPS_LOCAL_GOTNO: 1508 obj->local_gotno = dynp->d_un.d_val; 1509 break; 1510 1511 case DT_MIPS_SYMTABNO: 1512 obj->symtabno = dynp->d_un.d_val; 1513 break; 1514 1515 case DT_MIPS_GOTSYM: 1516 obj->gotsym = dynp->d_un.d_val; 1517 break; 1518 1519 case DT_MIPS_RLD_MAP: 1520 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1521 break; 1522 1523 case DT_MIPS_RLD_MAP_REL: 1524 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1525 // section relative to the address of the tag itself. 1526 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1527 (Elf_Addr) &r_debug; 1528 break; 1529 1530 case DT_MIPS_PLTGOT: 1531 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1532 dynp->d_un.d_ptr); 1533 break; 1534 1535 #endif 1536 1537 #ifdef __powerpc__ 1538 #ifdef __powerpc64__ 1539 case DT_PPC64_GLINK: 1540 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1541 break; 1542 #else 1543 case DT_PPC_GOT: 1544 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1545 break; 1546 #endif 1547 #endif 1548 1549 case DT_FLAGS_1: 1550 if (dynp->d_un.d_val & DF_1_NOOPEN) 1551 obj->z_noopen = true; 1552 if (dynp->d_un.d_val & DF_1_ORIGIN) 1553 obj->z_origin = true; 1554 if (dynp->d_un.d_val & DF_1_GLOBAL) 1555 obj->z_global = true; 1556 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1557 obj->bind_now = true; 1558 if (dynp->d_un.d_val & DF_1_NODELETE) 1559 obj->z_nodelete = true; 1560 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1561 obj->z_loadfltr = true; 1562 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1563 obj->z_interpose = true; 1564 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1565 obj->z_nodeflib = true; 1566 if (dynp->d_un.d_val & DF_1_PIE) 1567 obj->z_pie = true; 1568 break; 1569 1570 default: 1571 if (!early) { 1572 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1573 (long)dynp->d_tag); 1574 } 1575 break; 1576 } 1577 } 1578 1579 obj->traced = false; 1580 1581 if (plttype == DT_RELA) { 1582 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1583 obj->pltrel = NULL; 1584 obj->pltrelasize = obj->pltrelsize; 1585 obj->pltrelsize = 0; 1586 } 1587 1588 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1589 if (obj->valid_hash_sysv) 1590 obj->dynsymcount = obj->nchains; 1591 else if (obj->valid_hash_gnu) { 1592 obj->dynsymcount = 0; 1593 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1594 if (obj->buckets_gnu[bkt] == 0) 1595 continue; 1596 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1597 do 1598 obj->dynsymcount++; 1599 while ((*hashval++ & 1u) == 0); 1600 } 1601 obj->dynsymcount += obj->symndx_gnu; 1602 } 1603 1604 if (obj->linkmap.l_refname != NULL) 1605 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1606 linkmap.l_refname; 1607 } 1608 1609 static bool 1610 obj_resolve_origin(Obj_Entry *obj) 1611 { 1612 1613 if (obj->origin_path != NULL) 1614 return (true); 1615 obj->origin_path = xmalloc(PATH_MAX); 1616 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1617 } 1618 1619 static bool 1620 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1621 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1622 { 1623 1624 if (obj->z_origin && !obj_resolve_origin(obj)) 1625 return (false); 1626 1627 if (dyn_runpath != NULL) { 1628 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1629 obj->runpath = origin_subst(obj, obj->runpath); 1630 } else if (dyn_rpath != NULL) { 1631 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1632 obj->rpath = origin_subst(obj, obj->rpath); 1633 } 1634 if (dyn_soname != NULL) 1635 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1636 return (true); 1637 } 1638 1639 static bool 1640 digest_dynamic(Obj_Entry *obj, int early) 1641 { 1642 const Elf_Dyn *dyn_rpath; 1643 const Elf_Dyn *dyn_soname; 1644 const Elf_Dyn *dyn_runpath; 1645 1646 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1647 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1648 } 1649 1650 /* 1651 * Process a shared object's program header. This is used only for the 1652 * main program, when the kernel has already loaded the main program 1653 * into memory before calling the dynamic linker. It creates and 1654 * returns an Obj_Entry structure. 1655 */ 1656 static Obj_Entry * 1657 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1658 { 1659 Obj_Entry *obj; 1660 const Elf_Phdr *phlimit = phdr + phnum; 1661 const Elf_Phdr *ph; 1662 Elf_Addr note_start, note_end; 1663 int nsegs = 0; 1664 1665 obj = obj_new(); 1666 for (ph = phdr; ph < phlimit; ph++) { 1667 if (ph->p_type != PT_PHDR) 1668 continue; 1669 1670 obj->phdr = phdr; 1671 obj->phsize = ph->p_memsz; 1672 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1673 break; 1674 } 1675 1676 obj->stack_flags = PF_X | PF_R | PF_W; 1677 1678 for (ph = phdr; ph < phlimit; ph++) { 1679 switch (ph->p_type) { 1680 1681 case PT_INTERP: 1682 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1683 break; 1684 1685 case PT_LOAD: 1686 if (nsegs == 0) { /* First load segment */ 1687 obj->vaddrbase = trunc_page(ph->p_vaddr); 1688 obj->mapbase = obj->vaddrbase + obj->relocbase; 1689 } else { /* Last load segment */ 1690 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1691 obj->vaddrbase; 1692 } 1693 nsegs++; 1694 break; 1695 1696 case PT_DYNAMIC: 1697 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1698 break; 1699 1700 case PT_TLS: 1701 obj->tlsindex = 1; 1702 obj->tlssize = ph->p_memsz; 1703 obj->tlsalign = ph->p_align; 1704 obj->tlsinitsize = ph->p_filesz; 1705 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1706 obj->tlspoffset = ph->p_offset; 1707 break; 1708 1709 case PT_GNU_STACK: 1710 obj->stack_flags = ph->p_flags; 1711 break; 1712 1713 case PT_GNU_RELRO: 1714 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1715 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1716 trunc_page(ph->p_vaddr); 1717 break; 1718 1719 case PT_NOTE: 1720 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1721 note_end = note_start + ph->p_filesz; 1722 digest_notes(obj, note_start, note_end); 1723 break; 1724 } 1725 } 1726 if (nsegs < 1) { 1727 _rtld_error("%s: too few PT_LOAD segments", path); 1728 return (NULL); 1729 } 1730 1731 obj->entry = entry; 1732 return (obj); 1733 } 1734 1735 void 1736 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1737 { 1738 const Elf_Note *note; 1739 const char *note_name; 1740 uintptr_t p; 1741 1742 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1743 note = (const Elf_Note *)((const char *)(note + 1) + 1744 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1745 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1746 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1747 note->n_descsz != sizeof(int32_t)) 1748 continue; 1749 if (note->n_type != NT_FREEBSD_ABI_TAG && 1750 note->n_type != NT_FREEBSD_FEATURE_CTL && 1751 note->n_type != NT_FREEBSD_NOINIT_TAG) 1752 continue; 1753 note_name = (const char *)(note + 1); 1754 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1755 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1756 continue; 1757 switch (note->n_type) { 1758 case NT_FREEBSD_ABI_TAG: 1759 /* FreeBSD osrel note */ 1760 p = (uintptr_t)(note + 1); 1761 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1762 obj->osrel = *(const int32_t *)(p); 1763 dbg("note osrel %d", obj->osrel); 1764 break; 1765 case NT_FREEBSD_FEATURE_CTL: 1766 /* FreeBSD ABI feature control note */ 1767 p = (uintptr_t)(note + 1); 1768 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1769 obj->fctl0 = *(const uint32_t *)(p); 1770 dbg("note fctl0 %#x", obj->fctl0); 1771 break; 1772 case NT_FREEBSD_NOINIT_TAG: 1773 /* FreeBSD 'crt does not call init' note */ 1774 obj->crt_no_init = true; 1775 dbg("note crt_no_init"); 1776 break; 1777 } 1778 } 1779 } 1780 1781 static Obj_Entry * 1782 dlcheck(void *handle) 1783 { 1784 Obj_Entry *obj; 1785 1786 TAILQ_FOREACH(obj, &obj_list, next) { 1787 if (obj == (Obj_Entry *) handle) 1788 break; 1789 } 1790 1791 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1792 _rtld_error("Invalid shared object handle %p", handle); 1793 return (NULL); 1794 } 1795 return (obj); 1796 } 1797 1798 /* 1799 * If the given object is already in the donelist, return true. Otherwise 1800 * add the object to the list and return false. 1801 */ 1802 static bool 1803 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1804 { 1805 unsigned int i; 1806 1807 for (i = 0; i < dlp->num_used; i++) 1808 if (dlp->objs[i] == obj) 1809 return (true); 1810 /* 1811 * Our donelist allocation should always be sufficient. But if 1812 * our threads locking isn't working properly, more shared objects 1813 * could have been loaded since we allocated the list. That should 1814 * never happen, but we'll handle it properly just in case it does. 1815 */ 1816 if (dlp->num_used < dlp->num_alloc) 1817 dlp->objs[dlp->num_used++] = obj; 1818 return (false); 1819 } 1820 1821 /* 1822 * Hash function for symbol table lookup. Don't even think about changing 1823 * this. It is specified by the System V ABI. 1824 */ 1825 unsigned long 1826 elf_hash(const char *name) 1827 { 1828 const unsigned char *p = (const unsigned char *) name; 1829 unsigned long h = 0; 1830 unsigned long g; 1831 1832 while (*p != '\0') { 1833 h = (h << 4) + *p++; 1834 if ((g = h & 0xf0000000) != 0) 1835 h ^= g >> 24; 1836 h &= ~g; 1837 } 1838 return (h); 1839 } 1840 1841 /* 1842 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1843 * unsigned in case it's implemented with a wider type. 1844 */ 1845 static uint32_t 1846 gnu_hash(const char *s) 1847 { 1848 uint32_t h; 1849 unsigned char c; 1850 1851 h = 5381; 1852 for (c = *s; c != '\0'; c = *++s) 1853 h = h * 33 + c; 1854 return (h & 0xffffffff); 1855 } 1856 1857 1858 /* 1859 * Find the library with the given name, and return its full pathname. 1860 * The returned string is dynamically allocated. Generates an error 1861 * message and returns NULL if the library cannot be found. 1862 * 1863 * If the second argument is non-NULL, then it refers to an already- 1864 * loaded shared object, whose library search path will be searched. 1865 * 1866 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1867 * descriptor (which is close-on-exec) will be passed out via the third 1868 * argument. 1869 * 1870 * The search order is: 1871 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1872 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1873 * LD_LIBRARY_PATH 1874 * DT_RUNPATH in the referencing file 1875 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1876 * from list) 1877 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1878 * 1879 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1880 */ 1881 static char * 1882 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1883 { 1884 char *pathname, *refobj_path; 1885 const char *name; 1886 bool nodeflib, objgiven; 1887 1888 objgiven = refobj != NULL; 1889 1890 if (libmap_disable || !objgiven || 1891 (name = lm_find(refobj->path, xname)) == NULL) 1892 name = xname; 1893 1894 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1895 if (name[0] != '/' && !trust) { 1896 _rtld_error("Absolute pathname required " 1897 "for shared object \"%s\"", name); 1898 return (NULL); 1899 } 1900 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1901 __DECONST(char *, name))); 1902 } 1903 1904 dbg(" Searching for \"%s\"", name); 1905 refobj_path = objgiven ? refobj->path : NULL; 1906 1907 /* 1908 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1909 * back to pre-conforming behaviour if user requested so with 1910 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1911 * nodeflib. 1912 */ 1913 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1914 pathname = search_library_path(name, ld_library_path, 1915 refobj_path, fdp); 1916 if (pathname != NULL) 1917 return (pathname); 1918 if (refobj != NULL) { 1919 pathname = search_library_path(name, refobj->rpath, 1920 refobj_path, fdp); 1921 if (pathname != NULL) 1922 return (pathname); 1923 } 1924 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1925 if (pathname != NULL) 1926 return (pathname); 1927 pathname = search_library_path(name, gethints(false), 1928 refobj_path, fdp); 1929 if (pathname != NULL) 1930 return (pathname); 1931 pathname = search_library_path(name, ld_standard_library_path, 1932 refobj_path, fdp); 1933 if (pathname != NULL) 1934 return (pathname); 1935 } else { 1936 nodeflib = objgiven ? refobj->z_nodeflib : false; 1937 if (objgiven) { 1938 pathname = search_library_path(name, refobj->rpath, 1939 refobj->path, fdp); 1940 if (pathname != NULL) 1941 return (pathname); 1942 } 1943 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1944 pathname = search_library_path(name, obj_main->rpath, 1945 refobj_path, fdp); 1946 if (pathname != NULL) 1947 return (pathname); 1948 } 1949 pathname = search_library_path(name, ld_library_path, 1950 refobj_path, fdp); 1951 if (pathname != NULL) 1952 return (pathname); 1953 if (objgiven) { 1954 pathname = search_library_path(name, refobj->runpath, 1955 refobj_path, fdp); 1956 if (pathname != NULL) 1957 return (pathname); 1958 } 1959 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1960 if (pathname != NULL) 1961 return (pathname); 1962 pathname = search_library_path(name, gethints(nodeflib), 1963 refobj_path, fdp); 1964 if (pathname != NULL) 1965 return (pathname); 1966 if (objgiven && !nodeflib) { 1967 pathname = search_library_path(name, 1968 ld_standard_library_path, refobj_path, fdp); 1969 if (pathname != NULL) 1970 return (pathname); 1971 } 1972 } 1973 1974 if (objgiven && refobj->path != NULL) { 1975 _rtld_error("Shared object \"%s\" not found, " 1976 "required by \"%s\"", name, basename(refobj->path)); 1977 } else { 1978 _rtld_error("Shared object \"%s\" not found", name); 1979 } 1980 return (NULL); 1981 } 1982 1983 /* 1984 * Given a symbol number in a referencing object, find the corresponding 1985 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1986 * no definition was found. Returns a pointer to the Obj_Entry of the 1987 * defining object via the reference parameter DEFOBJ_OUT. 1988 */ 1989 const Elf_Sym * 1990 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1991 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1992 RtldLockState *lockstate) 1993 { 1994 const Elf_Sym *ref; 1995 const Elf_Sym *def; 1996 const Obj_Entry *defobj; 1997 const Ver_Entry *ve; 1998 SymLook req; 1999 const char *name; 2000 int res; 2001 2002 /* 2003 * If we have already found this symbol, get the information from 2004 * the cache. 2005 */ 2006 if (symnum >= refobj->dynsymcount) 2007 return (NULL); /* Bad object */ 2008 if (cache != NULL && cache[symnum].sym != NULL) { 2009 *defobj_out = cache[symnum].obj; 2010 return (cache[symnum].sym); 2011 } 2012 2013 ref = refobj->symtab + symnum; 2014 name = refobj->strtab + ref->st_name; 2015 def = NULL; 2016 defobj = NULL; 2017 ve = NULL; 2018 2019 /* 2020 * We don't have to do a full scale lookup if the symbol is local. 2021 * We know it will bind to the instance in this load module; to 2022 * which we already have a pointer (ie ref). By not doing a lookup, 2023 * we not only improve performance, but it also avoids unresolvable 2024 * symbols when local symbols are not in the hash table. This has 2025 * been seen with the ia64 toolchain. 2026 */ 2027 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2028 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2029 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2030 symnum); 2031 } 2032 symlook_init(&req, name); 2033 req.flags = flags; 2034 ve = req.ventry = fetch_ventry(refobj, symnum); 2035 req.lockstate = lockstate; 2036 res = symlook_default(&req, refobj); 2037 if (res == 0) { 2038 def = req.sym_out; 2039 defobj = req.defobj_out; 2040 } 2041 } else { 2042 def = ref; 2043 defobj = refobj; 2044 } 2045 2046 /* 2047 * If we found no definition and the reference is weak, treat the 2048 * symbol as having the value zero. 2049 */ 2050 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2051 def = &sym_zero; 2052 defobj = obj_main; 2053 } 2054 2055 if (def != NULL) { 2056 *defobj_out = defobj; 2057 /* Record the information in the cache to avoid subsequent lookups. */ 2058 if (cache != NULL) { 2059 cache[symnum].sym = def; 2060 cache[symnum].obj = defobj; 2061 } 2062 } else { 2063 if (refobj != &obj_rtld) 2064 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2065 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2066 } 2067 return (def); 2068 } 2069 2070 /* 2071 * Return the search path from the ldconfig hints file, reading it if 2072 * necessary. If nostdlib is true, then the default search paths are 2073 * not added to result. 2074 * 2075 * Returns NULL if there are problems with the hints file, 2076 * or if the search path there is empty. 2077 */ 2078 static const char * 2079 gethints(bool nostdlib) 2080 { 2081 static char *filtered_path; 2082 static const char *hints; 2083 static struct elfhints_hdr hdr; 2084 struct fill_search_info_args sargs, hargs; 2085 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2086 struct dl_serpath *SLPpath, *hintpath; 2087 char *p; 2088 struct stat hint_stat; 2089 unsigned int SLPndx, hintndx, fndx, fcount; 2090 int fd; 2091 size_t flen; 2092 uint32_t dl; 2093 bool skip; 2094 2095 /* First call, read the hints file */ 2096 if (hints == NULL) { 2097 /* Keep from trying again in case the hints file is bad. */ 2098 hints = ""; 2099 2100 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2101 return (NULL); 2102 2103 /* 2104 * Check of hdr.dirlistlen value against type limit 2105 * intends to pacify static analyzers. Further 2106 * paranoia leads to checks that dirlist is fully 2107 * contained in the file range. 2108 */ 2109 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2110 hdr.magic != ELFHINTS_MAGIC || 2111 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2112 fstat(fd, &hint_stat) == -1) { 2113 cleanup1: 2114 close(fd); 2115 hdr.dirlistlen = 0; 2116 return (NULL); 2117 } 2118 dl = hdr.strtab; 2119 if (dl + hdr.dirlist < dl) 2120 goto cleanup1; 2121 dl += hdr.dirlist; 2122 if (dl + hdr.dirlistlen < dl) 2123 goto cleanup1; 2124 dl += hdr.dirlistlen; 2125 if (dl > hint_stat.st_size) 2126 goto cleanup1; 2127 p = xmalloc(hdr.dirlistlen + 1); 2128 if (pread(fd, p, hdr.dirlistlen + 1, 2129 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2130 p[hdr.dirlistlen] != '\0') { 2131 free(p); 2132 goto cleanup1; 2133 } 2134 hints = p; 2135 close(fd); 2136 } 2137 2138 /* 2139 * If caller agreed to receive list which includes the default 2140 * paths, we are done. Otherwise, if we still did not 2141 * calculated filtered result, do it now. 2142 */ 2143 if (!nostdlib) 2144 return (hints[0] != '\0' ? hints : NULL); 2145 if (filtered_path != NULL) 2146 goto filt_ret; 2147 2148 /* 2149 * Obtain the list of all configured search paths, and the 2150 * list of the default paths. 2151 * 2152 * First estimate the size of the results. 2153 */ 2154 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2155 smeta.dls_cnt = 0; 2156 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2157 hmeta.dls_cnt = 0; 2158 2159 sargs.request = RTLD_DI_SERINFOSIZE; 2160 sargs.serinfo = &smeta; 2161 hargs.request = RTLD_DI_SERINFOSIZE; 2162 hargs.serinfo = &hmeta; 2163 2164 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2165 &sargs); 2166 path_enumerate(hints, fill_search_info, NULL, &hargs); 2167 2168 SLPinfo = xmalloc(smeta.dls_size); 2169 hintinfo = xmalloc(hmeta.dls_size); 2170 2171 /* 2172 * Next fetch both sets of paths. 2173 */ 2174 sargs.request = RTLD_DI_SERINFO; 2175 sargs.serinfo = SLPinfo; 2176 sargs.serpath = &SLPinfo->dls_serpath[0]; 2177 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2178 2179 hargs.request = RTLD_DI_SERINFO; 2180 hargs.serinfo = hintinfo; 2181 hargs.serpath = &hintinfo->dls_serpath[0]; 2182 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2183 2184 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2185 &sargs); 2186 path_enumerate(hints, fill_search_info, NULL, &hargs); 2187 2188 /* 2189 * Now calculate the difference between two sets, by excluding 2190 * standard paths from the full set. 2191 */ 2192 fndx = 0; 2193 fcount = 0; 2194 filtered_path = xmalloc(hdr.dirlistlen + 1); 2195 hintpath = &hintinfo->dls_serpath[0]; 2196 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2197 skip = false; 2198 SLPpath = &SLPinfo->dls_serpath[0]; 2199 /* 2200 * Check each standard path against current. 2201 */ 2202 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2203 /* matched, skip the path */ 2204 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2205 skip = true; 2206 break; 2207 } 2208 } 2209 if (skip) 2210 continue; 2211 /* 2212 * Not matched against any standard path, add the path 2213 * to result. Separate consequtive paths with ':'. 2214 */ 2215 if (fcount > 0) { 2216 filtered_path[fndx] = ':'; 2217 fndx++; 2218 } 2219 fcount++; 2220 flen = strlen(hintpath->dls_name); 2221 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2222 fndx += flen; 2223 } 2224 filtered_path[fndx] = '\0'; 2225 2226 free(SLPinfo); 2227 free(hintinfo); 2228 2229 filt_ret: 2230 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2231 } 2232 2233 static void 2234 init_dag(Obj_Entry *root) 2235 { 2236 const Needed_Entry *needed; 2237 const Objlist_Entry *elm; 2238 DoneList donelist; 2239 2240 if (root->dag_inited) 2241 return; 2242 donelist_init(&donelist); 2243 2244 /* Root object belongs to own DAG. */ 2245 objlist_push_tail(&root->dldags, root); 2246 objlist_push_tail(&root->dagmembers, root); 2247 donelist_check(&donelist, root); 2248 2249 /* 2250 * Add dependencies of root object to DAG in breadth order 2251 * by exploiting the fact that each new object get added 2252 * to the tail of the dagmembers list. 2253 */ 2254 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2255 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2256 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2257 continue; 2258 objlist_push_tail(&needed->obj->dldags, root); 2259 objlist_push_tail(&root->dagmembers, needed->obj); 2260 } 2261 } 2262 root->dag_inited = true; 2263 } 2264 2265 static void 2266 init_marker(Obj_Entry *marker) 2267 { 2268 2269 bzero(marker, sizeof(*marker)); 2270 marker->marker = true; 2271 } 2272 2273 Obj_Entry * 2274 globallist_curr(const Obj_Entry *obj) 2275 { 2276 2277 for (;;) { 2278 if (obj == NULL) 2279 return (NULL); 2280 if (!obj->marker) 2281 return (__DECONST(Obj_Entry *, obj)); 2282 obj = TAILQ_PREV(obj, obj_entry_q, next); 2283 } 2284 } 2285 2286 Obj_Entry * 2287 globallist_next(const Obj_Entry *obj) 2288 { 2289 2290 for (;;) { 2291 obj = TAILQ_NEXT(obj, next); 2292 if (obj == NULL) 2293 return (NULL); 2294 if (!obj->marker) 2295 return (__DECONST(Obj_Entry *, obj)); 2296 } 2297 } 2298 2299 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2300 static void 2301 hold_object(Obj_Entry *obj) 2302 { 2303 2304 obj->holdcount++; 2305 } 2306 2307 static void 2308 unhold_object(Obj_Entry *obj) 2309 { 2310 2311 assert(obj->holdcount > 0); 2312 if (--obj->holdcount == 0 && obj->unholdfree) 2313 release_object(obj); 2314 } 2315 2316 static void 2317 process_z(Obj_Entry *root) 2318 { 2319 const Objlist_Entry *elm; 2320 Obj_Entry *obj; 2321 2322 /* 2323 * Walk over object DAG and process every dependent object 2324 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2325 * to grow their own DAG. 2326 * 2327 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2328 * symlook_global() to work. 2329 * 2330 * For DF_1_NODELETE, the DAG should have its reference upped. 2331 */ 2332 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2333 obj = elm->obj; 2334 if (obj == NULL) 2335 continue; 2336 if (obj->z_nodelete && !obj->ref_nodel) { 2337 dbg("obj %s -z nodelete", obj->path); 2338 init_dag(obj); 2339 ref_dag(obj); 2340 obj->ref_nodel = true; 2341 } 2342 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2343 dbg("obj %s -z global", obj->path); 2344 objlist_push_tail(&list_global, obj); 2345 init_dag(obj); 2346 } 2347 } 2348 } 2349 2350 static void 2351 parse_rtld_phdr(Obj_Entry *obj) 2352 { 2353 const Elf_Phdr *ph; 2354 Elf_Addr note_start, note_end; 2355 2356 obj->stack_flags = PF_X | PF_R | PF_W; 2357 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2358 obj->phsize; ph++) { 2359 switch (ph->p_type) { 2360 case PT_GNU_STACK: 2361 obj->stack_flags = ph->p_flags; 2362 break; 2363 case PT_GNU_RELRO: 2364 obj->relro_page = obj->relocbase + 2365 trunc_page(ph->p_vaddr); 2366 obj->relro_size = round_page(ph->p_memsz); 2367 break; 2368 case PT_NOTE: 2369 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2370 note_end = note_start + ph->p_filesz; 2371 digest_notes(obj, note_start, note_end); 2372 break; 2373 } 2374 } 2375 } 2376 2377 /* 2378 * Initialize the dynamic linker. The argument is the address at which 2379 * the dynamic linker has been mapped into memory. The primary task of 2380 * this function is to relocate the dynamic linker. 2381 */ 2382 static void 2383 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2384 { 2385 Obj_Entry objtmp; /* Temporary rtld object */ 2386 const Elf_Ehdr *ehdr; 2387 const Elf_Dyn *dyn_rpath; 2388 const Elf_Dyn *dyn_soname; 2389 const Elf_Dyn *dyn_runpath; 2390 2391 #ifdef RTLD_INIT_PAGESIZES_EARLY 2392 /* The page size is required by the dynamic memory allocator. */ 2393 init_pagesizes(aux_info); 2394 #endif 2395 2396 /* 2397 * Conjure up an Obj_Entry structure for the dynamic linker. 2398 * 2399 * The "path" member can't be initialized yet because string constants 2400 * cannot yet be accessed. Below we will set it correctly. 2401 */ 2402 memset(&objtmp, 0, sizeof(objtmp)); 2403 objtmp.path = NULL; 2404 objtmp.rtld = true; 2405 objtmp.mapbase = mapbase; 2406 #ifdef PIC 2407 objtmp.relocbase = mapbase; 2408 #endif 2409 2410 objtmp.dynamic = rtld_dynamic(&objtmp); 2411 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2412 assert(objtmp.needed == NULL); 2413 #if !defined(__mips__) 2414 /* MIPS has a bogus DT_TEXTREL. */ 2415 assert(!objtmp.textrel); 2416 #endif 2417 /* 2418 * Temporarily put the dynamic linker entry into the object list, so 2419 * that symbols can be found. 2420 */ 2421 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2422 2423 ehdr = (Elf_Ehdr *)mapbase; 2424 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2425 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2426 2427 /* Initialize the object list. */ 2428 TAILQ_INIT(&obj_list); 2429 2430 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2431 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2432 2433 #ifndef RTLD_INIT_PAGESIZES_EARLY 2434 /* The page size is required by the dynamic memory allocator. */ 2435 init_pagesizes(aux_info); 2436 #endif 2437 2438 if (aux_info[AT_OSRELDATE] != NULL) 2439 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2440 2441 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2442 2443 /* Replace the path with a dynamically allocated copy. */ 2444 obj_rtld.path = xstrdup(ld_path_rtld); 2445 2446 parse_rtld_phdr(&obj_rtld); 2447 if (obj_enforce_relro(&obj_rtld) == -1) 2448 rtld_die(); 2449 2450 r_debug.r_version = R_DEBUG_VERSION; 2451 r_debug.r_brk = r_debug_state; 2452 r_debug.r_state = RT_CONSISTENT; 2453 r_debug.r_ldbase = obj_rtld.relocbase; 2454 } 2455 2456 /* 2457 * Retrieve the array of supported page sizes. The kernel provides the page 2458 * sizes in increasing order. 2459 */ 2460 static void 2461 init_pagesizes(Elf_Auxinfo **aux_info) 2462 { 2463 static size_t psa[MAXPAGESIZES]; 2464 int mib[2]; 2465 size_t len, size; 2466 2467 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2468 NULL) { 2469 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2470 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2471 } else { 2472 len = 2; 2473 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2474 size = sizeof(psa); 2475 else { 2476 /* As a fallback, retrieve the base page size. */ 2477 size = sizeof(psa[0]); 2478 if (aux_info[AT_PAGESZ] != NULL) { 2479 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2480 goto psa_filled; 2481 } else { 2482 mib[0] = CTL_HW; 2483 mib[1] = HW_PAGESIZE; 2484 len = 2; 2485 } 2486 } 2487 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2488 _rtld_error("sysctl for hw.pagesize(s) failed"); 2489 rtld_die(); 2490 } 2491 psa_filled: 2492 pagesizes = psa; 2493 } 2494 npagesizes = size / sizeof(pagesizes[0]); 2495 /* Discard any invalid entries at the end of the array. */ 2496 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2497 npagesizes--; 2498 } 2499 2500 /* 2501 * Add the init functions from a needed object list (and its recursive 2502 * needed objects) to "list". This is not used directly; it is a helper 2503 * function for initlist_add_objects(). The write lock must be held 2504 * when this function is called. 2505 */ 2506 static void 2507 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2508 { 2509 /* Recursively process the successor needed objects. */ 2510 if (needed->next != NULL) 2511 initlist_add_neededs(needed->next, list); 2512 2513 /* Process the current needed object. */ 2514 if (needed->obj != NULL) 2515 initlist_add_objects(needed->obj, needed->obj, list); 2516 } 2517 2518 /* 2519 * Scan all of the DAGs rooted in the range of objects from "obj" to 2520 * "tail" and add their init functions to "list". This recurses over 2521 * the DAGs and ensure the proper init ordering such that each object's 2522 * needed libraries are initialized before the object itself. At the 2523 * same time, this function adds the objects to the global finalization 2524 * list "list_fini" in the opposite order. The write lock must be 2525 * held when this function is called. 2526 */ 2527 static void 2528 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2529 { 2530 Obj_Entry *nobj; 2531 2532 if (obj->init_scanned || obj->init_done) 2533 return; 2534 obj->init_scanned = true; 2535 2536 /* Recursively process the successor objects. */ 2537 nobj = globallist_next(obj); 2538 if (nobj != NULL && obj != tail) 2539 initlist_add_objects(nobj, tail, list); 2540 2541 /* Recursively process the needed objects. */ 2542 if (obj->needed != NULL) 2543 initlist_add_neededs(obj->needed, list); 2544 if (obj->needed_filtees != NULL) 2545 initlist_add_neededs(obj->needed_filtees, list); 2546 if (obj->needed_aux_filtees != NULL) 2547 initlist_add_neededs(obj->needed_aux_filtees, list); 2548 2549 /* Add the object to the init list. */ 2550 objlist_push_tail(list, obj); 2551 2552 /* Add the object to the global fini list in the reverse order. */ 2553 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2554 && !obj->on_fini_list) { 2555 objlist_push_head(&list_fini, obj); 2556 obj->on_fini_list = true; 2557 } 2558 } 2559 2560 #ifndef FPTR_TARGET 2561 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2562 #endif 2563 2564 static void 2565 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2566 { 2567 Needed_Entry *needed, *needed1; 2568 2569 for (needed = n; needed != NULL; needed = needed->next) { 2570 if (needed->obj != NULL) { 2571 dlclose_locked(needed->obj, lockstate); 2572 needed->obj = NULL; 2573 } 2574 } 2575 for (needed = n; needed != NULL; needed = needed1) { 2576 needed1 = needed->next; 2577 free(needed); 2578 } 2579 } 2580 2581 static void 2582 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2583 { 2584 2585 free_needed_filtees(obj->needed_filtees, lockstate); 2586 obj->needed_filtees = NULL; 2587 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2588 obj->needed_aux_filtees = NULL; 2589 obj->filtees_loaded = false; 2590 } 2591 2592 static void 2593 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2594 RtldLockState *lockstate) 2595 { 2596 2597 for (; needed != NULL; needed = needed->next) { 2598 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2599 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2600 RTLD_LOCAL, lockstate); 2601 } 2602 } 2603 2604 static void 2605 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2606 { 2607 2608 lock_restart_for_upgrade(lockstate); 2609 if (!obj->filtees_loaded) { 2610 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2611 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2612 obj->filtees_loaded = true; 2613 } 2614 } 2615 2616 static int 2617 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2618 { 2619 Obj_Entry *obj1; 2620 2621 for (; needed != NULL; needed = needed->next) { 2622 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2623 flags & ~RTLD_LO_NOLOAD); 2624 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2625 return (-1); 2626 } 2627 return (0); 2628 } 2629 2630 /* 2631 * Given a shared object, traverse its list of needed objects, and load 2632 * each of them. Returns 0 on success. Generates an error message and 2633 * returns -1 on failure. 2634 */ 2635 static int 2636 load_needed_objects(Obj_Entry *first, int flags) 2637 { 2638 Obj_Entry *obj; 2639 2640 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2641 if (obj->marker) 2642 continue; 2643 if (process_needed(obj, obj->needed, flags) == -1) 2644 return (-1); 2645 } 2646 return (0); 2647 } 2648 2649 static int 2650 load_preload_objects(const char *penv, bool isfd) 2651 { 2652 Obj_Entry *obj; 2653 const char *name; 2654 size_t len; 2655 char savech, *p, *psave; 2656 int fd; 2657 static const char delim[] = " \t:;"; 2658 2659 if (penv == NULL) 2660 return (0); 2661 2662 p = psave = xstrdup(penv); 2663 p += strspn(p, delim); 2664 while (*p != '\0') { 2665 len = strcspn(p, delim); 2666 2667 savech = p[len]; 2668 p[len] = '\0'; 2669 if (isfd) { 2670 name = NULL; 2671 fd = parse_integer(p); 2672 if (fd == -1) { 2673 free(psave); 2674 return (-1); 2675 } 2676 } else { 2677 name = p; 2678 fd = -1; 2679 } 2680 2681 obj = load_object(name, fd, NULL, 0); 2682 if (obj == NULL) { 2683 free(psave); 2684 return (-1); /* XXX - cleanup */ 2685 } 2686 obj->z_interpose = true; 2687 p[len] = savech; 2688 p += len; 2689 p += strspn(p, delim); 2690 } 2691 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2692 2693 free(psave); 2694 return (0); 2695 } 2696 2697 static const char * 2698 printable_path(const char *path) 2699 { 2700 2701 return (path == NULL ? "<unknown>" : path); 2702 } 2703 2704 /* 2705 * Load a shared object into memory, if it is not already loaded. The 2706 * object may be specified by name or by user-supplied file descriptor 2707 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2708 * duplicate is. 2709 * 2710 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2711 * on failure. 2712 */ 2713 static Obj_Entry * 2714 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2715 { 2716 Obj_Entry *obj; 2717 int fd; 2718 struct stat sb; 2719 char *path; 2720 2721 fd = -1; 2722 if (name != NULL) { 2723 TAILQ_FOREACH(obj, &obj_list, next) { 2724 if (obj->marker || obj->doomed) 2725 continue; 2726 if (object_match_name(obj, name)) 2727 return (obj); 2728 } 2729 2730 path = find_library(name, refobj, &fd); 2731 if (path == NULL) 2732 return (NULL); 2733 } else 2734 path = NULL; 2735 2736 if (fd >= 0) { 2737 /* 2738 * search_library_pathfds() opens a fresh file descriptor for the 2739 * library, so there is no need to dup(). 2740 */ 2741 } else if (fd_u == -1) { 2742 /* 2743 * If we didn't find a match by pathname, or the name is not 2744 * supplied, open the file and check again by device and inode. 2745 * This avoids false mismatches caused by multiple links or ".." 2746 * in pathnames. 2747 * 2748 * To avoid a race, we open the file and use fstat() rather than 2749 * using stat(). 2750 */ 2751 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2752 _rtld_error("Cannot open \"%s\"", path); 2753 free(path); 2754 return (NULL); 2755 } 2756 } else { 2757 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2758 if (fd == -1) { 2759 _rtld_error("Cannot dup fd"); 2760 free(path); 2761 return (NULL); 2762 } 2763 } 2764 if (fstat(fd, &sb) == -1) { 2765 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2766 close(fd); 2767 free(path); 2768 return (NULL); 2769 } 2770 TAILQ_FOREACH(obj, &obj_list, next) { 2771 if (obj->marker || obj->doomed) 2772 continue; 2773 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2774 break; 2775 } 2776 if (obj != NULL && name != NULL) { 2777 object_add_name(obj, name); 2778 free(path); 2779 close(fd); 2780 return (obj); 2781 } 2782 if (flags & RTLD_LO_NOLOAD) { 2783 free(path); 2784 close(fd); 2785 return (NULL); 2786 } 2787 2788 /* First use of this object, so we must map it in */ 2789 obj = do_load_object(fd, name, path, &sb, flags); 2790 if (obj == NULL) 2791 free(path); 2792 close(fd); 2793 2794 return (obj); 2795 } 2796 2797 static Obj_Entry * 2798 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2799 int flags) 2800 { 2801 Obj_Entry *obj; 2802 struct statfs fs; 2803 2804 /* 2805 * First, make sure that environment variables haven't been 2806 * used to circumvent the noexec flag on a filesystem. 2807 * We ignore fstatfs(2) failures, since fd might reference 2808 * not a file, e.g. shmfd. 2809 */ 2810 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2811 (fs.f_flags & MNT_NOEXEC) != 0) { 2812 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2813 return (NULL); 2814 } 2815 2816 dbg("loading \"%s\"", printable_path(path)); 2817 obj = map_object(fd, printable_path(path), sbp); 2818 if (obj == NULL) 2819 return (NULL); 2820 2821 /* 2822 * If DT_SONAME is present in the object, digest_dynamic2 already 2823 * added it to the object names. 2824 */ 2825 if (name != NULL) 2826 object_add_name(obj, name); 2827 obj->path = path; 2828 if (!digest_dynamic(obj, 0)) 2829 goto errp; 2830 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2831 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2832 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2833 dbg("refusing to load PIE executable \"%s\"", obj->path); 2834 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2835 goto errp; 2836 } 2837 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2838 RTLD_LO_DLOPEN) { 2839 dbg("refusing to load non-loadable \"%s\"", obj->path); 2840 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2841 goto errp; 2842 } 2843 2844 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2845 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2846 obj_count++; 2847 obj_loads++; 2848 linkmap_add(obj); /* for GDB & dlinfo() */ 2849 max_stack_flags |= obj->stack_flags; 2850 2851 dbg(" %p .. %p: %s", obj->mapbase, 2852 obj->mapbase + obj->mapsize - 1, obj->path); 2853 if (obj->textrel) 2854 dbg(" WARNING: %s has impure text", obj->path); 2855 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2856 obj->path); 2857 2858 return (obj); 2859 2860 errp: 2861 munmap(obj->mapbase, obj->mapsize); 2862 obj_free(obj); 2863 return (NULL); 2864 } 2865 2866 static int 2867 load_kpreload(const void *addr) 2868 { 2869 Obj_Entry *obj; 2870 const Elf_Ehdr *ehdr; 2871 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2872 static const char kname[] = "[vdso]"; 2873 2874 ehdr = addr; 2875 if (!check_elf_headers(ehdr, "kpreload")) 2876 return (-1); 2877 obj = obj_new(); 2878 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2879 obj->phdr = phdr; 2880 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2881 phlimit = phdr + ehdr->e_phnum; 2882 seg0 = segn = NULL; 2883 2884 for (; phdr < phlimit; phdr++) { 2885 switch (phdr->p_type) { 2886 case PT_DYNAMIC: 2887 phdyn = phdr; 2888 break; 2889 case PT_GNU_STACK: 2890 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2891 obj->stack_flags = phdr->p_flags; 2892 break; 2893 case PT_LOAD: 2894 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2895 seg0 = phdr; 2896 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2897 phdr->p_vaddr + phdr->p_memsz) 2898 segn = phdr; 2899 break; 2900 } 2901 } 2902 2903 obj->mapbase = __DECONST(caddr_t, addr); 2904 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2905 obj->vaddrbase = 0; 2906 obj->relocbase = obj->mapbase; 2907 2908 object_add_name(obj, kname); 2909 obj->path = xstrdup(kname); 2910 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2911 2912 if (!digest_dynamic(obj, 0)) { 2913 obj_free(obj); 2914 return (-1); 2915 } 2916 2917 /* 2918 * We assume that kernel-preloaded object does not need 2919 * relocation. It is currently written into read-only page, 2920 * handling relocations would mean we need to allocate at 2921 * least one additional page per AS. 2922 */ 2923 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2924 obj->path, obj->mapbase, obj->phdr, seg0, 2925 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2926 2927 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2928 obj_count++; 2929 obj_loads++; 2930 linkmap_add(obj); /* for GDB & dlinfo() */ 2931 max_stack_flags |= obj->stack_flags; 2932 2933 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2934 return (0); 2935 } 2936 2937 Obj_Entry * 2938 obj_from_addr(const void *addr) 2939 { 2940 Obj_Entry *obj; 2941 2942 TAILQ_FOREACH(obj, &obj_list, next) { 2943 if (obj->marker) 2944 continue; 2945 if (addr < (void *) obj->mapbase) 2946 continue; 2947 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2948 return obj; 2949 } 2950 return (NULL); 2951 } 2952 2953 static void 2954 preinit_main(void) 2955 { 2956 Elf_Addr *preinit_addr; 2957 int index; 2958 2959 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2960 if (preinit_addr == NULL) 2961 return; 2962 2963 for (index = 0; index < obj_main->preinit_array_num; index++) { 2964 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2965 dbg("calling preinit function for %s at %p", obj_main->path, 2966 (void *)preinit_addr[index]); 2967 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2968 0, 0, obj_main->path); 2969 call_init_pointer(obj_main, preinit_addr[index]); 2970 } 2971 } 2972 } 2973 2974 /* 2975 * Call the finalization functions for each of the objects in "list" 2976 * belonging to the DAG of "root" and referenced once. If NULL "root" 2977 * is specified, every finalization function will be called regardless 2978 * of the reference count and the list elements won't be freed. All of 2979 * the objects are expected to have non-NULL fini functions. 2980 */ 2981 static void 2982 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2983 { 2984 Objlist_Entry *elm; 2985 struct dlerror_save *saved_msg; 2986 Elf_Addr *fini_addr; 2987 int index; 2988 2989 assert(root == NULL || root->refcount == 1); 2990 2991 if (root != NULL) 2992 root->doomed = true; 2993 2994 /* 2995 * Preserve the current error message since a fini function might 2996 * call into the dynamic linker and overwrite it. 2997 */ 2998 saved_msg = errmsg_save(); 2999 do { 3000 STAILQ_FOREACH(elm, list, link) { 3001 if (root != NULL && (elm->obj->refcount != 1 || 3002 objlist_find(&root->dagmembers, elm->obj) == NULL)) 3003 continue; 3004 /* Remove object from fini list to prevent recursive invocation. */ 3005 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3006 /* Ensure that new references cannot be acquired. */ 3007 elm->obj->doomed = true; 3008 3009 hold_object(elm->obj); 3010 lock_release(rtld_bind_lock, lockstate); 3011 /* 3012 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3013 * When this happens, DT_FINI_ARRAY is processed first. 3014 */ 3015 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3016 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3017 for (index = elm->obj->fini_array_num - 1; index >= 0; 3018 index--) { 3019 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3020 dbg("calling fini function for %s at %p", 3021 elm->obj->path, (void *)fini_addr[index]); 3022 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3023 (void *)fini_addr[index], 0, 0, elm->obj->path); 3024 call_initfini_pointer(elm->obj, fini_addr[index]); 3025 } 3026 } 3027 } 3028 if (elm->obj->fini != (Elf_Addr)NULL) { 3029 dbg("calling fini function for %s at %p", elm->obj->path, 3030 (void *)elm->obj->fini); 3031 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3032 0, 0, elm->obj->path); 3033 call_initfini_pointer(elm->obj, elm->obj->fini); 3034 } 3035 wlock_acquire(rtld_bind_lock, lockstate); 3036 unhold_object(elm->obj); 3037 /* No need to free anything if process is going down. */ 3038 if (root != NULL) 3039 free(elm); 3040 /* 3041 * We must restart the list traversal after every fini call 3042 * because a dlclose() call from the fini function or from 3043 * another thread might have modified the reference counts. 3044 */ 3045 break; 3046 } 3047 } while (elm != NULL); 3048 errmsg_restore(saved_msg); 3049 } 3050 3051 /* 3052 * Call the initialization functions for each of the objects in 3053 * "list". All of the objects are expected to have non-NULL init 3054 * functions. 3055 */ 3056 static void 3057 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3058 { 3059 Objlist_Entry *elm; 3060 Obj_Entry *obj; 3061 struct dlerror_save *saved_msg; 3062 Elf_Addr *init_addr; 3063 void (*reg)(void (*)(void)); 3064 int index; 3065 3066 /* 3067 * Clean init_scanned flag so that objects can be rechecked and 3068 * possibly initialized earlier if any of vectors called below 3069 * cause the change by using dlopen. 3070 */ 3071 TAILQ_FOREACH(obj, &obj_list, next) { 3072 if (obj->marker) 3073 continue; 3074 obj->init_scanned = false; 3075 } 3076 3077 /* 3078 * Preserve the current error message since an init function might 3079 * call into the dynamic linker and overwrite it. 3080 */ 3081 saved_msg = errmsg_save(); 3082 STAILQ_FOREACH(elm, list, link) { 3083 if (elm->obj->init_done) /* Initialized early. */ 3084 continue; 3085 /* 3086 * Race: other thread might try to use this object before current 3087 * one completes the initialization. Not much can be done here 3088 * without better locking. 3089 */ 3090 elm->obj->init_done = true; 3091 hold_object(elm->obj); 3092 reg = NULL; 3093 if (elm->obj == obj_main && obj_main->crt_no_init) { 3094 reg = (void (*)(void (*)(void)))get_program_var_addr( 3095 "__libc_atexit", lockstate); 3096 } 3097 lock_release(rtld_bind_lock, lockstate); 3098 if (reg != NULL) { 3099 reg(rtld_exit); 3100 rtld_exit_ptr = rtld_nop_exit; 3101 } 3102 3103 /* 3104 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3105 * When this happens, DT_INIT is processed first. 3106 */ 3107 if (elm->obj->init != (Elf_Addr)NULL) { 3108 dbg("calling init function for %s at %p", elm->obj->path, 3109 (void *)elm->obj->init); 3110 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3111 0, 0, elm->obj->path); 3112 call_init_pointer(elm->obj, elm->obj->init); 3113 } 3114 init_addr = (Elf_Addr *)elm->obj->init_array; 3115 if (init_addr != NULL) { 3116 for (index = 0; index < elm->obj->init_array_num; index++) { 3117 if (init_addr[index] != 0 && init_addr[index] != 1) { 3118 dbg("calling init function for %s at %p", elm->obj->path, 3119 (void *)init_addr[index]); 3120 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3121 (void *)init_addr[index], 0, 0, elm->obj->path); 3122 call_init_pointer(elm->obj, init_addr[index]); 3123 } 3124 } 3125 } 3126 wlock_acquire(rtld_bind_lock, lockstate); 3127 unhold_object(elm->obj); 3128 } 3129 errmsg_restore(saved_msg); 3130 } 3131 3132 static void 3133 objlist_clear(Objlist *list) 3134 { 3135 Objlist_Entry *elm; 3136 3137 while (!STAILQ_EMPTY(list)) { 3138 elm = STAILQ_FIRST(list); 3139 STAILQ_REMOVE_HEAD(list, link); 3140 free(elm); 3141 } 3142 } 3143 3144 static Objlist_Entry * 3145 objlist_find(Objlist *list, const Obj_Entry *obj) 3146 { 3147 Objlist_Entry *elm; 3148 3149 STAILQ_FOREACH(elm, list, link) 3150 if (elm->obj == obj) 3151 return elm; 3152 return (NULL); 3153 } 3154 3155 static void 3156 objlist_init(Objlist *list) 3157 { 3158 STAILQ_INIT(list); 3159 } 3160 3161 static void 3162 objlist_push_head(Objlist *list, Obj_Entry *obj) 3163 { 3164 Objlist_Entry *elm; 3165 3166 elm = NEW(Objlist_Entry); 3167 elm->obj = obj; 3168 STAILQ_INSERT_HEAD(list, elm, link); 3169 } 3170 3171 static void 3172 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3173 { 3174 Objlist_Entry *elm; 3175 3176 elm = NEW(Objlist_Entry); 3177 elm->obj = obj; 3178 STAILQ_INSERT_TAIL(list, elm, link); 3179 } 3180 3181 static void 3182 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3183 { 3184 Objlist_Entry *elm, *listelm; 3185 3186 STAILQ_FOREACH(listelm, list, link) { 3187 if (listelm->obj == listobj) 3188 break; 3189 } 3190 elm = NEW(Objlist_Entry); 3191 elm->obj = obj; 3192 if (listelm != NULL) 3193 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3194 else 3195 STAILQ_INSERT_TAIL(list, elm, link); 3196 } 3197 3198 static void 3199 objlist_remove(Objlist *list, Obj_Entry *obj) 3200 { 3201 Objlist_Entry *elm; 3202 3203 if ((elm = objlist_find(list, obj)) != NULL) { 3204 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3205 free(elm); 3206 } 3207 } 3208 3209 /* 3210 * Relocate dag rooted in the specified object. 3211 * Returns 0 on success, or -1 on failure. 3212 */ 3213 3214 static int 3215 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3216 int flags, RtldLockState *lockstate) 3217 { 3218 Objlist_Entry *elm; 3219 int error; 3220 3221 error = 0; 3222 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3223 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3224 lockstate); 3225 if (error == -1) 3226 break; 3227 } 3228 return (error); 3229 } 3230 3231 /* 3232 * Prepare for, or clean after, relocating an object marked with 3233 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3234 * segments are remapped read-write. After relocations are done, the 3235 * segment's permissions are returned back to the modes specified in 3236 * the phdrs. If any relocation happened, or always for wired 3237 * program, COW is triggered. 3238 */ 3239 static int 3240 reloc_textrel_prot(Obj_Entry *obj, bool before) 3241 { 3242 const Elf_Phdr *ph; 3243 void *base; 3244 size_t l, sz; 3245 int prot; 3246 3247 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3248 l--, ph++) { 3249 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3250 continue; 3251 base = obj->relocbase + trunc_page(ph->p_vaddr); 3252 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3253 trunc_page(ph->p_vaddr); 3254 prot = before ? (PROT_READ | PROT_WRITE) : 3255 convert_prot(ph->p_flags); 3256 if (mprotect(base, sz, prot) == -1) { 3257 _rtld_error("%s: Cannot write-%sable text segment: %s", 3258 obj->path, before ? "en" : "dis", 3259 rtld_strerror(errno)); 3260 return (-1); 3261 } 3262 } 3263 return (0); 3264 } 3265 3266 /* Process RELR relative relocations. */ 3267 static void 3268 reloc_relr(Obj_Entry *obj) 3269 { 3270 const Elf_Relr *relr, *relrlim; 3271 Elf_Addr *where; 3272 3273 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3274 for (relr = obj->relr; relr < relrlim; relr++) { 3275 Elf_Relr entry = *relr; 3276 3277 if ((entry & 1) == 0) { 3278 where = (Elf_Addr *)(obj->relocbase + entry); 3279 *where++ += (Elf_Addr)obj->relocbase; 3280 } else { 3281 for (long i = 0; (entry >>= 1) != 0; i++) 3282 if ((entry & 1) != 0) 3283 where[i] += (Elf_Addr)obj->relocbase; 3284 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3285 } 3286 } 3287 } 3288 3289 /* 3290 * Relocate single object. 3291 * Returns 0 on success, or -1 on failure. 3292 */ 3293 static int 3294 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3295 int flags, RtldLockState *lockstate) 3296 { 3297 3298 if (obj->relocated) 3299 return (0); 3300 obj->relocated = true; 3301 if (obj != rtldobj) 3302 dbg("relocating \"%s\"", obj->path); 3303 3304 if (obj->symtab == NULL || obj->strtab == NULL || 3305 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3306 dbg("object %s has no run-time symbol table", obj->path); 3307 3308 /* There are relocations to the write-protected text segment. */ 3309 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3310 return (-1); 3311 3312 /* Process the non-PLT non-IFUNC relocations. */ 3313 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3314 return (-1); 3315 reloc_relr(obj); 3316 3317 /* Re-protected the text segment. */ 3318 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3319 return (-1); 3320 3321 /* Set the special PLT or GOT entries. */ 3322 init_pltgot(obj); 3323 3324 /* Process the PLT relocations. */ 3325 if (reloc_plt(obj, flags, lockstate) == -1) 3326 return (-1); 3327 /* Relocate the jump slots if we are doing immediate binding. */ 3328 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3329 lockstate) == -1) 3330 return (-1); 3331 3332 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3333 return (-1); 3334 3335 /* 3336 * Set up the magic number and version in the Obj_Entry. These 3337 * were checked in the crt1.o from the original ElfKit, so we 3338 * set them for backward compatibility. 3339 */ 3340 obj->magic = RTLD_MAGIC; 3341 obj->version = RTLD_VERSION; 3342 3343 return (0); 3344 } 3345 3346 /* 3347 * Relocate newly-loaded shared objects. The argument is a pointer to 3348 * the Obj_Entry for the first such object. All objects from the first 3349 * to the end of the list of objects are relocated. Returns 0 on success, 3350 * or -1 on failure. 3351 */ 3352 static int 3353 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3354 int flags, RtldLockState *lockstate) 3355 { 3356 Obj_Entry *obj; 3357 int error; 3358 3359 for (error = 0, obj = first; obj != NULL; 3360 obj = TAILQ_NEXT(obj, next)) { 3361 if (obj->marker) 3362 continue; 3363 error = relocate_object(obj, bind_now, rtldobj, flags, 3364 lockstate); 3365 if (error == -1) 3366 break; 3367 } 3368 return (error); 3369 } 3370 3371 /* 3372 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3373 * referencing STT_GNU_IFUNC symbols is postponed till the other 3374 * relocations are done. The indirect functions specified as 3375 * ifunc are allowed to call other symbols, so we need to have 3376 * objects relocated before asking for resolution from indirects. 3377 * 3378 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3379 * instead of the usual lazy handling of PLT slots. It is 3380 * consistent with how GNU does it. 3381 */ 3382 static int 3383 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3384 RtldLockState *lockstate) 3385 { 3386 3387 if (obj->ifuncs_resolved) 3388 return (0); 3389 obj->ifuncs_resolved = true; 3390 if (!obj->irelative && !obj->irelative_nonplt && 3391 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3392 !obj->non_plt_gnu_ifunc) 3393 return (0); 3394 if (obj_disable_relro(obj) == -1 || 3395 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3396 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3397 lockstate) == -1) || 3398 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3399 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3400 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3401 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3402 obj_enforce_relro(obj) == -1) 3403 return (-1); 3404 return (0); 3405 } 3406 3407 static int 3408 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3409 RtldLockState *lockstate) 3410 { 3411 Objlist_Entry *elm; 3412 Obj_Entry *obj; 3413 3414 STAILQ_FOREACH(elm, list, link) { 3415 obj = elm->obj; 3416 if (obj->marker) 3417 continue; 3418 if (resolve_object_ifunc(obj, bind_now, flags, 3419 lockstate) == -1) 3420 return (-1); 3421 } 3422 return (0); 3423 } 3424 3425 /* 3426 * Cleanup procedure. It will be called (by the atexit mechanism) just 3427 * before the process exits. 3428 */ 3429 static void 3430 rtld_exit(void) 3431 { 3432 RtldLockState lockstate; 3433 3434 wlock_acquire(rtld_bind_lock, &lockstate); 3435 dbg("rtld_exit()"); 3436 objlist_call_fini(&list_fini, NULL, &lockstate); 3437 /* No need to remove the items from the list, since we are exiting. */ 3438 if (!libmap_disable) 3439 lm_fini(); 3440 lock_release(rtld_bind_lock, &lockstate); 3441 } 3442 3443 static void 3444 rtld_nop_exit(void) 3445 { 3446 } 3447 3448 /* 3449 * Iterate over a search path, translate each element, and invoke the 3450 * callback on the result. 3451 */ 3452 static void * 3453 path_enumerate(const char *path, path_enum_proc callback, 3454 const char *refobj_path, void *arg) 3455 { 3456 const char *trans; 3457 if (path == NULL) 3458 return (NULL); 3459 3460 path += strspn(path, ":;"); 3461 while (*path != '\0') { 3462 size_t len; 3463 char *res; 3464 3465 len = strcspn(path, ":;"); 3466 trans = lm_findn(refobj_path, path, len); 3467 if (trans) 3468 res = callback(trans, strlen(trans), arg); 3469 else 3470 res = callback(path, len, arg); 3471 3472 if (res != NULL) 3473 return (res); 3474 3475 path += len; 3476 path += strspn(path, ":;"); 3477 } 3478 3479 return (NULL); 3480 } 3481 3482 struct try_library_args { 3483 const char *name; 3484 size_t namelen; 3485 char *buffer; 3486 size_t buflen; 3487 int fd; 3488 }; 3489 3490 static void * 3491 try_library_path(const char *dir, size_t dirlen, void *param) 3492 { 3493 struct try_library_args *arg; 3494 int fd; 3495 3496 arg = param; 3497 if (*dir == '/' || trust) { 3498 char *pathname; 3499 3500 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3501 return (NULL); 3502 3503 pathname = arg->buffer; 3504 strncpy(pathname, dir, dirlen); 3505 pathname[dirlen] = '/'; 3506 strcpy(pathname + dirlen + 1, arg->name); 3507 3508 dbg(" Trying \"%s\"", pathname); 3509 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3510 if (fd >= 0) { 3511 dbg(" Opened \"%s\", fd %d", pathname, fd); 3512 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3513 strcpy(pathname, arg->buffer); 3514 arg->fd = fd; 3515 return (pathname); 3516 } else { 3517 dbg(" Failed to open \"%s\": %s", 3518 pathname, rtld_strerror(errno)); 3519 } 3520 } 3521 return (NULL); 3522 } 3523 3524 static char * 3525 search_library_path(const char *name, const char *path, 3526 const char *refobj_path, int *fdp) 3527 { 3528 char *p; 3529 struct try_library_args arg; 3530 3531 if (path == NULL) 3532 return (NULL); 3533 3534 arg.name = name; 3535 arg.namelen = strlen(name); 3536 arg.buffer = xmalloc(PATH_MAX); 3537 arg.buflen = PATH_MAX; 3538 arg.fd = -1; 3539 3540 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3541 *fdp = arg.fd; 3542 3543 free(arg.buffer); 3544 3545 return (p); 3546 } 3547 3548 3549 /* 3550 * Finds the library with the given name using the directory descriptors 3551 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3552 * 3553 * Returns a freshly-opened close-on-exec file descriptor for the library, 3554 * or -1 if the library cannot be found. 3555 */ 3556 static char * 3557 search_library_pathfds(const char *name, const char *path, int *fdp) 3558 { 3559 char *envcopy, *fdstr, *found, *last_token; 3560 size_t len; 3561 int dirfd, fd; 3562 3563 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3564 3565 /* Don't load from user-specified libdirs into setuid binaries. */ 3566 if (!trust) 3567 return (NULL); 3568 3569 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3570 if (path == NULL) 3571 return (NULL); 3572 3573 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3574 if (name[0] == '/') { 3575 dbg("Absolute path (%s) passed to %s", name, __func__); 3576 return (NULL); 3577 } 3578 3579 /* 3580 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3581 * copy of the path, as strtok_r rewrites separator tokens 3582 * with '\0'. 3583 */ 3584 found = NULL; 3585 envcopy = xstrdup(path); 3586 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3587 fdstr = strtok_r(NULL, ":", &last_token)) { 3588 dirfd = parse_integer(fdstr); 3589 if (dirfd < 0) { 3590 _rtld_error("failed to parse directory FD: '%s'", 3591 fdstr); 3592 break; 3593 } 3594 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3595 if (fd >= 0) { 3596 *fdp = fd; 3597 len = strlen(fdstr) + strlen(name) + 3; 3598 found = xmalloc(len); 3599 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3600 _rtld_error("error generating '%d/%s'", 3601 dirfd, name); 3602 rtld_die(); 3603 } 3604 dbg("open('%s') => %d", found, fd); 3605 break; 3606 } 3607 } 3608 free(envcopy); 3609 3610 return (found); 3611 } 3612 3613 3614 int 3615 dlclose(void *handle) 3616 { 3617 RtldLockState lockstate; 3618 int error; 3619 3620 wlock_acquire(rtld_bind_lock, &lockstate); 3621 error = dlclose_locked(handle, &lockstate); 3622 lock_release(rtld_bind_lock, &lockstate); 3623 return (error); 3624 } 3625 3626 static int 3627 dlclose_locked(void *handle, RtldLockState *lockstate) 3628 { 3629 Obj_Entry *root; 3630 3631 root = dlcheck(handle); 3632 if (root == NULL) 3633 return (-1); 3634 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3635 root->path); 3636 3637 /* Unreference the object and its dependencies. */ 3638 root->dl_refcount--; 3639 3640 if (root->refcount == 1) { 3641 /* 3642 * The object will be no longer referenced, so we must unload it. 3643 * First, call the fini functions. 3644 */ 3645 objlist_call_fini(&list_fini, root, lockstate); 3646 3647 unref_dag(root); 3648 3649 /* Finish cleaning up the newly-unreferenced objects. */ 3650 GDB_STATE(RT_DELETE,&root->linkmap); 3651 unload_object(root, lockstate); 3652 GDB_STATE(RT_CONSISTENT,NULL); 3653 } else 3654 unref_dag(root); 3655 3656 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3657 return (0); 3658 } 3659 3660 char * 3661 dlerror(void) 3662 { 3663 if (*(lockinfo.dlerror_seen()) != 0) 3664 return (NULL); 3665 *lockinfo.dlerror_seen() = 1; 3666 return (lockinfo.dlerror_loc()); 3667 } 3668 3669 /* 3670 * This function is deprecated and has no effect. 3671 */ 3672 void 3673 dllockinit(void *context, 3674 void *(*_lock_create)(void *context) __unused, 3675 void (*_rlock_acquire)(void *lock) __unused, 3676 void (*_wlock_acquire)(void *lock) __unused, 3677 void (*_lock_release)(void *lock) __unused, 3678 void (*_lock_destroy)(void *lock) __unused, 3679 void (*context_destroy)(void *context)) 3680 { 3681 static void *cur_context; 3682 static void (*cur_context_destroy)(void *); 3683 3684 /* Just destroy the context from the previous call, if necessary. */ 3685 if (cur_context_destroy != NULL) 3686 cur_context_destroy(cur_context); 3687 cur_context = context; 3688 cur_context_destroy = context_destroy; 3689 } 3690 3691 void * 3692 dlopen(const char *name, int mode) 3693 { 3694 3695 return (rtld_dlopen(name, -1, mode)); 3696 } 3697 3698 void * 3699 fdlopen(int fd, int mode) 3700 { 3701 3702 return (rtld_dlopen(NULL, fd, mode)); 3703 } 3704 3705 static void * 3706 rtld_dlopen(const char *name, int fd, int mode) 3707 { 3708 RtldLockState lockstate; 3709 int lo_flags; 3710 3711 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3712 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3713 if (ld_tracing != NULL) { 3714 rlock_acquire(rtld_bind_lock, &lockstate); 3715 if (sigsetjmp(lockstate.env, 0) != 0) 3716 lock_upgrade(rtld_bind_lock, &lockstate); 3717 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3718 lock_release(rtld_bind_lock, &lockstate); 3719 } 3720 lo_flags = RTLD_LO_DLOPEN; 3721 if (mode & RTLD_NODELETE) 3722 lo_flags |= RTLD_LO_NODELETE; 3723 if (mode & RTLD_NOLOAD) 3724 lo_flags |= RTLD_LO_NOLOAD; 3725 if (mode & RTLD_DEEPBIND) 3726 lo_flags |= RTLD_LO_DEEPBIND; 3727 if (ld_tracing != NULL) 3728 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3729 3730 return (dlopen_object(name, fd, obj_main, lo_flags, 3731 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3732 } 3733 3734 static void 3735 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3736 { 3737 3738 obj->dl_refcount--; 3739 unref_dag(obj); 3740 if (obj->refcount == 0) 3741 unload_object(obj, lockstate); 3742 } 3743 3744 static Obj_Entry * 3745 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3746 int mode, RtldLockState *lockstate) 3747 { 3748 Obj_Entry *old_obj_tail; 3749 Obj_Entry *obj; 3750 Objlist initlist; 3751 RtldLockState mlockstate; 3752 int result; 3753 3754 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3755 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3756 refobj->path, lo_flags, mode); 3757 objlist_init(&initlist); 3758 3759 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3760 wlock_acquire(rtld_bind_lock, &mlockstate); 3761 lockstate = &mlockstate; 3762 } 3763 GDB_STATE(RT_ADD,NULL); 3764 3765 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3766 obj = NULL; 3767 if (name == NULL && fd == -1) { 3768 obj = obj_main; 3769 obj->refcount++; 3770 } else { 3771 obj = load_object(name, fd, refobj, lo_flags); 3772 } 3773 3774 if (obj) { 3775 obj->dl_refcount++; 3776 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3777 objlist_push_tail(&list_global, obj); 3778 if (globallist_next(old_obj_tail) != NULL) { 3779 /* We loaded something new. */ 3780 assert(globallist_next(old_obj_tail) == obj); 3781 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3782 obj->symbolic = true; 3783 result = 0; 3784 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3785 obj->static_tls && !allocate_tls_offset(obj)) { 3786 _rtld_error("%s: No space available " 3787 "for static Thread Local Storage", obj->path); 3788 result = -1; 3789 } 3790 if (result != -1) 3791 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3792 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3793 init_dag(obj); 3794 ref_dag(obj); 3795 if (result != -1) 3796 result = rtld_verify_versions(&obj->dagmembers); 3797 if (result != -1 && ld_tracing) 3798 goto trace; 3799 if (result == -1 || relocate_object_dag(obj, 3800 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3801 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3802 lockstate) == -1) { 3803 dlopen_cleanup(obj, lockstate); 3804 obj = NULL; 3805 } else if (lo_flags & RTLD_LO_EARLY) { 3806 /* 3807 * Do not call the init functions for early loaded 3808 * filtees. The image is still not initialized enough 3809 * for them to work. 3810 * 3811 * Our object is found by the global object list and 3812 * will be ordered among all init calls done right 3813 * before transferring control to main. 3814 */ 3815 } else { 3816 /* Make list of init functions to call. */ 3817 initlist_add_objects(obj, obj, &initlist); 3818 } 3819 /* 3820 * Process all no_delete or global objects here, given 3821 * them own DAGs to prevent their dependencies from being 3822 * unloaded. This has to be done after we have loaded all 3823 * of the dependencies, so that we do not miss any. 3824 */ 3825 if (obj != NULL) 3826 process_z(obj); 3827 } else { 3828 /* 3829 * Bump the reference counts for objects on this DAG. If 3830 * this is the first dlopen() call for the object that was 3831 * already loaded as a dependency, initialize the dag 3832 * starting at it. 3833 */ 3834 init_dag(obj); 3835 ref_dag(obj); 3836 3837 if ((lo_flags & RTLD_LO_TRACE) != 0) 3838 goto trace; 3839 } 3840 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3841 obj->z_nodelete) && !obj->ref_nodel) { 3842 dbg("obj %s nodelete", obj->path); 3843 ref_dag(obj); 3844 obj->z_nodelete = obj->ref_nodel = true; 3845 } 3846 } 3847 3848 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3849 name); 3850 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3851 3852 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3853 map_stacks_exec(lockstate); 3854 if (obj != NULL) 3855 distribute_static_tls(&initlist, lockstate); 3856 } 3857 3858 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3859 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3860 lockstate) == -1) { 3861 objlist_clear(&initlist); 3862 dlopen_cleanup(obj, lockstate); 3863 if (lockstate == &mlockstate) 3864 lock_release(rtld_bind_lock, lockstate); 3865 return (NULL); 3866 } 3867 3868 if (!(lo_flags & RTLD_LO_EARLY)) { 3869 /* Call the init functions. */ 3870 objlist_call_init(&initlist, lockstate); 3871 } 3872 objlist_clear(&initlist); 3873 if (lockstate == &mlockstate) 3874 lock_release(rtld_bind_lock, lockstate); 3875 return (obj); 3876 trace: 3877 trace_loaded_objects(obj); 3878 if (lockstate == &mlockstate) 3879 lock_release(rtld_bind_lock, lockstate); 3880 exit(0); 3881 } 3882 3883 static void * 3884 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3885 int flags) 3886 { 3887 DoneList donelist; 3888 const Obj_Entry *obj, *defobj; 3889 const Elf_Sym *def; 3890 SymLook req; 3891 RtldLockState lockstate; 3892 tls_index ti; 3893 void *sym; 3894 int res; 3895 3896 def = NULL; 3897 defobj = NULL; 3898 symlook_init(&req, name); 3899 req.ventry = ve; 3900 req.flags = flags | SYMLOOK_IN_PLT; 3901 req.lockstate = &lockstate; 3902 3903 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3904 rlock_acquire(rtld_bind_lock, &lockstate); 3905 if (sigsetjmp(lockstate.env, 0) != 0) 3906 lock_upgrade(rtld_bind_lock, &lockstate); 3907 if (handle == NULL || handle == RTLD_NEXT || 3908 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3909 3910 if ((obj = obj_from_addr(retaddr)) == NULL) { 3911 _rtld_error("Cannot determine caller's shared object"); 3912 lock_release(rtld_bind_lock, &lockstate); 3913 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3914 return (NULL); 3915 } 3916 if (handle == NULL) { /* Just the caller's shared object. */ 3917 res = symlook_obj(&req, obj); 3918 if (res == 0) { 3919 def = req.sym_out; 3920 defobj = req.defobj_out; 3921 } 3922 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3923 handle == RTLD_SELF) { /* ... caller included */ 3924 if (handle == RTLD_NEXT) 3925 obj = globallist_next(obj); 3926 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3927 if (obj->marker) 3928 continue; 3929 res = symlook_obj(&req, obj); 3930 if (res == 0) { 3931 if (def == NULL || (ld_dynamic_weak && 3932 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3933 def = req.sym_out; 3934 defobj = req.defobj_out; 3935 if (!ld_dynamic_weak || 3936 ELF_ST_BIND(def->st_info) != STB_WEAK) 3937 break; 3938 } 3939 } 3940 } 3941 /* 3942 * Search the dynamic linker itself, and possibly resolve the 3943 * symbol from there. This is how the application links to 3944 * dynamic linker services such as dlopen. 3945 * Note that we ignore ld_dynamic_weak == false case, 3946 * always overriding weak symbols by rtld definitions. 3947 */ 3948 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3949 res = symlook_obj(&req, &obj_rtld); 3950 if (res == 0) { 3951 def = req.sym_out; 3952 defobj = req.defobj_out; 3953 } 3954 } 3955 } else { 3956 assert(handle == RTLD_DEFAULT); 3957 res = symlook_default(&req, obj); 3958 if (res == 0) { 3959 defobj = req.defobj_out; 3960 def = req.sym_out; 3961 } 3962 } 3963 } else { 3964 if ((obj = dlcheck(handle)) == NULL) { 3965 lock_release(rtld_bind_lock, &lockstate); 3966 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3967 return (NULL); 3968 } 3969 3970 donelist_init(&donelist); 3971 if (obj->mainprog) { 3972 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3973 res = symlook_global(&req, &donelist); 3974 if (res == 0) { 3975 def = req.sym_out; 3976 defobj = req.defobj_out; 3977 } 3978 /* 3979 * Search the dynamic linker itself, and possibly resolve the 3980 * symbol from there. This is how the application links to 3981 * dynamic linker services such as dlopen. 3982 */ 3983 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3984 res = symlook_obj(&req, &obj_rtld); 3985 if (res == 0) { 3986 def = req.sym_out; 3987 defobj = req.defobj_out; 3988 } 3989 } 3990 } 3991 else { 3992 /* Search the whole DAG rooted at the given object. */ 3993 res = symlook_list(&req, &obj->dagmembers, &donelist); 3994 if (res == 0) { 3995 def = req.sym_out; 3996 defobj = req.defobj_out; 3997 } 3998 } 3999 } 4000 4001 if (def != NULL) { 4002 lock_release(rtld_bind_lock, &lockstate); 4003 4004 /* 4005 * The value required by the caller is derived from the value 4006 * of the symbol. this is simply the relocated value of the 4007 * symbol. 4008 */ 4009 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 4010 sym = make_function_pointer(def, defobj); 4011 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 4012 sym = rtld_resolve_ifunc(defobj, def); 4013 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4014 ti.ti_module = defobj->tlsindex; 4015 ti.ti_offset = def->st_value; 4016 sym = __tls_get_addr(&ti); 4017 } else 4018 sym = defobj->relocbase + def->st_value; 4019 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4020 return (sym); 4021 } 4022 4023 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4024 ve != NULL ? ve->name : ""); 4025 lock_release(rtld_bind_lock, &lockstate); 4026 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4027 return (NULL); 4028 } 4029 4030 void * 4031 dlsym(void *handle, const char *name) 4032 { 4033 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4034 SYMLOOK_DLSYM)); 4035 } 4036 4037 dlfunc_t 4038 dlfunc(void *handle, const char *name) 4039 { 4040 union { 4041 void *d; 4042 dlfunc_t f; 4043 } rv; 4044 4045 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4046 SYMLOOK_DLSYM); 4047 return (rv.f); 4048 } 4049 4050 void * 4051 dlvsym(void *handle, const char *name, const char *version) 4052 { 4053 Ver_Entry ventry; 4054 4055 ventry.name = version; 4056 ventry.file = NULL; 4057 ventry.hash = elf_hash(version); 4058 ventry.flags= 0; 4059 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4060 SYMLOOK_DLSYM)); 4061 } 4062 4063 int 4064 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4065 { 4066 const Obj_Entry *obj; 4067 RtldLockState lockstate; 4068 4069 rlock_acquire(rtld_bind_lock, &lockstate); 4070 obj = obj_from_addr(addr); 4071 if (obj == NULL) { 4072 _rtld_error("No shared object contains address"); 4073 lock_release(rtld_bind_lock, &lockstate); 4074 return (0); 4075 } 4076 rtld_fill_dl_phdr_info(obj, phdr_info); 4077 lock_release(rtld_bind_lock, &lockstate); 4078 return (1); 4079 } 4080 4081 int 4082 dladdr(const void *addr, Dl_info *info) 4083 { 4084 const Obj_Entry *obj; 4085 const Elf_Sym *def; 4086 void *symbol_addr; 4087 unsigned long symoffset; 4088 RtldLockState lockstate; 4089 4090 rlock_acquire(rtld_bind_lock, &lockstate); 4091 obj = obj_from_addr(addr); 4092 if (obj == NULL) { 4093 _rtld_error("No shared object contains address"); 4094 lock_release(rtld_bind_lock, &lockstate); 4095 return (0); 4096 } 4097 info->dli_fname = obj->path; 4098 info->dli_fbase = obj->mapbase; 4099 info->dli_saddr = (void *)0; 4100 info->dli_sname = NULL; 4101 4102 /* 4103 * Walk the symbol list looking for the symbol whose address is 4104 * closest to the address sent in. 4105 */ 4106 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4107 def = obj->symtab + symoffset; 4108 4109 /* 4110 * For skip the symbol if st_shndx is either SHN_UNDEF or 4111 * SHN_COMMON. 4112 */ 4113 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4114 continue; 4115 4116 /* 4117 * If the symbol is greater than the specified address, or if it 4118 * is further away from addr than the current nearest symbol, 4119 * then reject it. 4120 */ 4121 symbol_addr = obj->relocbase + def->st_value; 4122 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4123 continue; 4124 4125 /* Update our idea of the nearest symbol. */ 4126 info->dli_sname = obj->strtab + def->st_name; 4127 info->dli_saddr = symbol_addr; 4128 4129 /* Exact match? */ 4130 if (info->dli_saddr == addr) 4131 break; 4132 } 4133 lock_release(rtld_bind_lock, &lockstate); 4134 return (1); 4135 } 4136 4137 int 4138 dlinfo(void *handle, int request, void *p) 4139 { 4140 const Obj_Entry *obj; 4141 RtldLockState lockstate; 4142 int error; 4143 4144 rlock_acquire(rtld_bind_lock, &lockstate); 4145 4146 if (handle == NULL || handle == RTLD_SELF) { 4147 void *retaddr; 4148 4149 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4150 if ((obj = obj_from_addr(retaddr)) == NULL) 4151 _rtld_error("Cannot determine caller's shared object"); 4152 } else 4153 obj = dlcheck(handle); 4154 4155 if (obj == NULL) { 4156 lock_release(rtld_bind_lock, &lockstate); 4157 return (-1); 4158 } 4159 4160 error = 0; 4161 switch (request) { 4162 case RTLD_DI_LINKMAP: 4163 *((struct link_map const **)p) = &obj->linkmap; 4164 break; 4165 case RTLD_DI_ORIGIN: 4166 error = rtld_dirname(obj->path, p); 4167 break; 4168 4169 case RTLD_DI_SERINFOSIZE: 4170 case RTLD_DI_SERINFO: 4171 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4172 break; 4173 4174 default: 4175 _rtld_error("Invalid request %d passed to dlinfo()", request); 4176 error = -1; 4177 } 4178 4179 lock_release(rtld_bind_lock, &lockstate); 4180 4181 return (error); 4182 } 4183 4184 static void 4185 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4186 { 4187 Elf_Addr **dtvp; 4188 4189 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4190 phdr_info->dlpi_name = obj->path; 4191 phdr_info->dlpi_phdr = obj->phdr; 4192 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4193 phdr_info->dlpi_tls_modid = obj->tlsindex; 4194 dtvp = _get_tp(); 4195 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4196 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4197 phdr_info->dlpi_adds = obj_loads; 4198 phdr_info->dlpi_subs = obj_loads - obj_count; 4199 } 4200 4201 int 4202 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4203 { 4204 struct dl_phdr_info phdr_info; 4205 Obj_Entry *obj, marker; 4206 RtldLockState bind_lockstate, phdr_lockstate; 4207 int error; 4208 4209 init_marker(&marker); 4210 error = 0; 4211 4212 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4213 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4214 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4215 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4216 rtld_fill_dl_phdr_info(obj, &phdr_info); 4217 hold_object(obj); 4218 lock_release(rtld_bind_lock, &bind_lockstate); 4219 4220 error = callback(&phdr_info, sizeof phdr_info, param); 4221 4222 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4223 unhold_object(obj); 4224 obj = globallist_next(&marker); 4225 TAILQ_REMOVE(&obj_list, &marker, next); 4226 if (error != 0) { 4227 lock_release(rtld_bind_lock, &bind_lockstate); 4228 lock_release(rtld_phdr_lock, &phdr_lockstate); 4229 return (error); 4230 } 4231 } 4232 4233 if (error == 0) { 4234 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4235 lock_release(rtld_bind_lock, &bind_lockstate); 4236 error = callback(&phdr_info, sizeof(phdr_info), param); 4237 } 4238 lock_release(rtld_phdr_lock, &phdr_lockstate); 4239 return (error); 4240 } 4241 4242 static void * 4243 fill_search_info(const char *dir, size_t dirlen, void *param) 4244 { 4245 struct fill_search_info_args *arg; 4246 4247 arg = param; 4248 4249 if (arg->request == RTLD_DI_SERINFOSIZE) { 4250 arg->serinfo->dls_cnt ++; 4251 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4252 } else { 4253 struct dl_serpath *s_entry; 4254 4255 s_entry = arg->serpath; 4256 s_entry->dls_name = arg->strspace; 4257 s_entry->dls_flags = arg->flags; 4258 4259 strncpy(arg->strspace, dir, dirlen); 4260 arg->strspace[dirlen] = '\0'; 4261 4262 arg->strspace += dirlen + 1; 4263 arg->serpath++; 4264 } 4265 4266 return (NULL); 4267 } 4268 4269 static int 4270 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4271 { 4272 struct dl_serinfo _info; 4273 struct fill_search_info_args args; 4274 4275 args.request = RTLD_DI_SERINFOSIZE; 4276 args.serinfo = &_info; 4277 4278 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4279 _info.dls_cnt = 0; 4280 4281 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4282 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4283 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4284 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4285 if (!obj->z_nodeflib) 4286 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4287 4288 4289 if (request == RTLD_DI_SERINFOSIZE) { 4290 info->dls_size = _info.dls_size; 4291 info->dls_cnt = _info.dls_cnt; 4292 return (0); 4293 } 4294 4295 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4296 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4297 return (-1); 4298 } 4299 4300 args.request = RTLD_DI_SERINFO; 4301 args.serinfo = info; 4302 args.serpath = &info->dls_serpath[0]; 4303 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4304 4305 args.flags = LA_SER_RUNPATH; 4306 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4307 return (-1); 4308 4309 args.flags = LA_SER_LIBPATH; 4310 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4311 return (-1); 4312 4313 args.flags = LA_SER_RUNPATH; 4314 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4315 return (-1); 4316 4317 args.flags = LA_SER_CONFIG; 4318 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4319 != NULL) 4320 return (-1); 4321 4322 args.flags = LA_SER_DEFAULT; 4323 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4324 fill_search_info, NULL, &args) != NULL) 4325 return (-1); 4326 return (0); 4327 } 4328 4329 static int 4330 rtld_dirname(const char *path, char *bname) 4331 { 4332 const char *endp; 4333 4334 /* Empty or NULL string gets treated as "." */ 4335 if (path == NULL || *path == '\0') { 4336 bname[0] = '.'; 4337 bname[1] = '\0'; 4338 return (0); 4339 } 4340 4341 /* Strip trailing slashes */ 4342 endp = path + strlen(path) - 1; 4343 while (endp > path && *endp == '/') 4344 endp--; 4345 4346 /* Find the start of the dir */ 4347 while (endp > path && *endp != '/') 4348 endp--; 4349 4350 /* Either the dir is "/" or there are no slashes */ 4351 if (endp == path) { 4352 bname[0] = *endp == '/' ? '/' : '.'; 4353 bname[1] = '\0'; 4354 return (0); 4355 } else { 4356 do { 4357 endp--; 4358 } while (endp > path && *endp == '/'); 4359 } 4360 4361 if (endp - path + 2 > PATH_MAX) 4362 { 4363 _rtld_error("Filename is too long: %s", path); 4364 return(-1); 4365 } 4366 4367 strncpy(bname, path, endp - path + 1); 4368 bname[endp - path + 1] = '\0'; 4369 return (0); 4370 } 4371 4372 static int 4373 rtld_dirname_abs(const char *path, char *base) 4374 { 4375 char *last; 4376 4377 if (realpath(path, base) == NULL) { 4378 _rtld_error("realpath \"%s\" failed (%s)", path, 4379 rtld_strerror(errno)); 4380 return (-1); 4381 } 4382 dbg("%s -> %s", path, base); 4383 last = strrchr(base, '/'); 4384 if (last == NULL) { 4385 _rtld_error("non-abs result from realpath \"%s\"", path); 4386 return (-1); 4387 } 4388 if (last != base) 4389 *last = '\0'; 4390 return (0); 4391 } 4392 4393 static void 4394 linkmap_add(Obj_Entry *obj) 4395 { 4396 struct link_map *l, *prev; 4397 4398 l = &obj->linkmap; 4399 l->l_name = obj->path; 4400 l->l_base = obj->mapbase; 4401 l->l_ld = obj->dynamic; 4402 l->l_addr = obj->relocbase; 4403 4404 if (r_debug.r_map == NULL) { 4405 r_debug.r_map = l; 4406 return; 4407 } 4408 4409 /* 4410 * Scan to the end of the list, but not past the entry for the 4411 * dynamic linker, which we want to keep at the very end. 4412 */ 4413 for (prev = r_debug.r_map; 4414 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4415 prev = prev->l_next) 4416 ; 4417 4418 /* Link in the new entry. */ 4419 l->l_prev = prev; 4420 l->l_next = prev->l_next; 4421 if (l->l_next != NULL) 4422 l->l_next->l_prev = l; 4423 prev->l_next = l; 4424 } 4425 4426 static void 4427 linkmap_delete(Obj_Entry *obj) 4428 { 4429 struct link_map *l; 4430 4431 l = &obj->linkmap; 4432 if (l->l_prev == NULL) { 4433 if ((r_debug.r_map = l->l_next) != NULL) 4434 l->l_next->l_prev = NULL; 4435 return; 4436 } 4437 4438 if ((l->l_prev->l_next = l->l_next) != NULL) 4439 l->l_next->l_prev = l->l_prev; 4440 } 4441 4442 /* 4443 * Function for the debugger to set a breakpoint on to gain control. 4444 * 4445 * The two parameters allow the debugger to easily find and determine 4446 * what the runtime loader is doing and to whom it is doing it. 4447 * 4448 * When the loadhook trap is hit (r_debug_state, set at program 4449 * initialization), the arguments can be found on the stack: 4450 * 4451 * +8 struct link_map *m 4452 * +4 struct r_debug *rd 4453 * +0 RetAddr 4454 */ 4455 void 4456 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4457 { 4458 /* 4459 * The following is a hack to force the compiler to emit calls to 4460 * this function, even when optimizing. If the function is empty, 4461 * the compiler is not obliged to emit any code for calls to it, 4462 * even when marked __noinline. However, gdb depends on those 4463 * calls being made. 4464 */ 4465 __compiler_membar(); 4466 } 4467 4468 /* 4469 * A function called after init routines have completed. This can be used to 4470 * break before a program's entry routine is called, and can be used when 4471 * main is not available in the symbol table. 4472 */ 4473 void 4474 _r_debug_postinit(struct link_map *m __unused) 4475 { 4476 4477 /* See r_debug_state(). */ 4478 __compiler_membar(); 4479 } 4480 4481 static void 4482 release_object(Obj_Entry *obj) 4483 { 4484 4485 if (obj->holdcount > 0) { 4486 obj->unholdfree = true; 4487 return; 4488 } 4489 munmap(obj->mapbase, obj->mapsize); 4490 linkmap_delete(obj); 4491 obj_free(obj); 4492 } 4493 4494 /* 4495 * Get address of the pointer variable in the main program. 4496 * Prefer non-weak symbol over the weak one. 4497 */ 4498 static const void ** 4499 get_program_var_addr(const char *name, RtldLockState *lockstate) 4500 { 4501 SymLook req; 4502 DoneList donelist; 4503 4504 symlook_init(&req, name); 4505 req.lockstate = lockstate; 4506 donelist_init(&donelist); 4507 if (symlook_global(&req, &donelist) != 0) 4508 return (NULL); 4509 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4510 return ((const void **)make_function_pointer(req.sym_out, 4511 req.defobj_out)); 4512 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4513 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4514 else 4515 return ((const void **)(req.defobj_out->relocbase + 4516 req.sym_out->st_value)); 4517 } 4518 4519 /* 4520 * Set a pointer variable in the main program to the given value. This 4521 * is used to set key variables such as "environ" before any of the 4522 * init functions are called. 4523 */ 4524 static void 4525 set_program_var(const char *name, const void *value) 4526 { 4527 const void **addr; 4528 4529 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4530 dbg("\"%s\": *%p <-- %p", name, addr, value); 4531 *addr = value; 4532 } 4533 } 4534 4535 /* 4536 * Search the global objects, including dependencies and main object, 4537 * for the given symbol. 4538 */ 4539 static int 4540 symlook_global(SymLook *req, DoneList *donelist) 4541 { 4542 SymLook req1; 4543 const Objlist_Entry *elm; 4544 int res; 4545 4546 symlook_init_from_req(&req1, req); 4547 4548 /* Search all objects loaded at program start up. */ 4549 if (req->defobj_out == NULL || (ld_dynamic_weak && 4550 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4551 res = symlook_list(&req1, &list_main, donelist); 4552 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4553 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4554 req->sym_out = req1.sym_out; 4555 req->defobj_out = req1.defobj_out; 4556 assert(req->defobj_out != NULL); 4557 } 4558 } 4559 4560 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4561 STAILQ_FOREACH(elm, &list_global, link) { 4562 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4563 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4564 break; 4565 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4566 if (res == 0 && (req->defobj_out == NULL || 4567 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4568 req->sym_out = req1.sym_out; 4569 req->defobj_out = req1.defobj_out; 4570 assert(req->defobj_out != NULL); 4571 } 4572 } 4573 4574 return (req->sym_out != NULL ? 0 : ESRCH); 4575 } 4576 4577 /* 4578 * Given a symbol name in a referencing object, find the corresponding 4579 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4580 * no definition was found. Returns a pointer to the Obj_Entry of the 4581 * defining object via the reference parameter DEFOBJ_OUT. 4582 */ 4583 static int 4584 symlook_default(SymLook *req, const Obj_Entry *refobj) 4585 { 4586 DoneList donelist; 4587 const Objlist_Entry *elm; 4588 SymLook req1; 4589 int res; 4590 4591 donelist_init(&donelist); 4592 symlook_init_from_req(&req1, req); 4593 4594 /* 4595 * Look first in the referencing object if linked symbolically, 4596 * and similarly handle protected symbols. 4597 */ 4598 res = symlook_obj(&req1, refobj); 4599 if (res == 0 && (refobj->symbolic || 4600 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4601 req->sym_out = req1.sym_out; 4602 req->defobj_out = req1.defobj_out; 4603 assert(req->defobj_out != NULL); 4604 } 4605 if (refobj->symbolic || req->defobj_out != NULL) 4606 donelist_check(&donelist, refobj); 4607 4608 symlook_global(req, &donelist); 4609 4610 /* Search all dlopened DAGs containing the referencing object. */ 4611 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4612 if (req->sym_out != NULL && (!ld_dynamic_weak || 4613 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4614 break; 4615 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4616 if (res == 0 && (req->sym_out == NULL || 4617 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4618 req->sym_out = req1.sym_out; 4619 req->defobj_out = req1.defobj_out; 4620 assert(req->defobj_out != NULL); 4621 } 4622 } 4623 4624 /* 4625 * Search the dynamic linker itself, and possibly resolve the 4626 * symbol from there. This is how the application links to 4627 * dynamic linker services such as dlopen. 4628 */ 4629 if (req->sym_out == NULL || 4630 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4631 res = symlook_obj(&req1, &obj_rtld); 4632 if (res == 0) { 4633 req->sym_out = req1.sym_out; 4634 req->defobj_out = req1.defobj_out; 4635 assert(req->defobj_out != NULL); 4636 } 4637 } 4638 4639 return (req->sym_out != NULL ? 0 : ESRCH); 4640 } 4641 4642 static int 4643 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4644 { 4645 const Elf_Sym *def; 4646 const Obj_Entry *defobj; 4647 const Objlist_Entry *elm; 4648 SymLook req1; 4649 int res; 4650 4651 def = NULL; 4652 defobj = NULL; 4653 STAILQ_FOREACH(elm, objlist, link) { 4654 if (donelist_check(dlp, elm->obj)) 4655 continue; 4656 symlook_init_from_req(&req1, req); 4657 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4658 if (def == NULL || (ld_dynamic_weak && 4659 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4660 def = req1.sym_out; 4661 defobj = req1.defobj_out; 4662 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4663 break; 4664 } 4665 } 4666 } 4667 if (def != NULL) { 4668 req->sym_out = def; 4669 req->defobj_out = defobj; 4670 return (0); 4671 } 4672 return (ESRCH); 4673 } 4674 4675 /* 4676 * Search the chain of DAGS cointed to by the given Needed_Entry 4677 * for a symbol of the given name. Each DAG is scanned completely 4678 * before advancing to the next one. Returns a pointer to the symbol, 4679 * or NULL if no definition was found. 4680 */ 4681 static int 4682 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4683 { 4684 const Elf_Sym *def; 4685 const Needed_Entry *n; 4686 const Obj_Entry *defobj; 4687 SymLook req1; 4688 int res; 4689 4690 def = NULL; 4691 defobj = NULL; 4692 symlook_init_from_req(&req1, req); 4693 for (n = needed; n != NULL; n = n->next) { 4694 if (n->obj == NULL || 4695 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4696 continue; 4697 if (def == NULL || (ld_dynamic_weak && 4698 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4699 def = req1.sym_out; 4700 defobj = req1.defobj_out; 4701 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4702 break; 4703 } 4704 } 4705 if (def != NULL) { 4706 req->sym_out = def; 4707 req->defobj_out = defobj; 4708 return (0); 4709 } 4710 return (ESRCH); 4711 } 4712 4713 /* 4714 * Search the symbol table of a single shared object for a symbol of 4715 * the given name and version, if requested. Returns a pointer to the 4716 * symbol, or NULL if no definition was found. If the object is 4717 * filter, return filtered symbol from filtee. 4718 * 4719 * The symbol's hash value is passed in for efficiency reasons; that 4720 * eliminates many recomputations of the hash value. 4721 */ 4722 int 4723 symlook_obj(SymLook *req, const Obj_Entry *obj) 4724 { 4725 DoneList donelist; 4726 SymLook req1; 4727 int flags, res, mres; 4728 4729 /* 4730 * If there is at least one valid hash at this point, we prefer to 4731 * use the faster GNU version if available. 4732 */ 4733 if (obj->valid_hash_gnu) 4734 mres = symlook_obj1_gnu(req, obj); 4735 else if (obj->valid_hash_sysv) 4736 mres = symlook_obj1_sysv(req, obj); 4737 else 4738 return (EINVAL); 4739 4740 if (mres == 0) { 4741 if (obj->needed_filtees != NULL) { 4742 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4743 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4744 donelist_init(&donelist); 4745 symlook_init_from_req(&req1, req); 4746 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4747 if (res == 0) { 4748 req->sym_out = req1.sym_out; 4749 req->defobj_out = req1.defobj_out; 4750 } 4751 return (res); 4752 } 4753 if (obj->needed_aux_filtees != NULL) { 4754 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4755 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4756 donelist_init(&donelist); 4757 symlook_init_from_req(&req1, req); 4758 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4759 if (res == 0) { 4760 req->sym_out = req1.sym_out; 4761 req->defobj_out = req1.defobj_out; 4762 return (res); 4763 } 4764 } 4765 } 4766 return (mres); 4767 } 4768 4769 /* Symbol match routine common to both hash functions */ 4770 static bool 4771 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4772 const unsigned long symnum) 4773 { 4774 Elf_Versym verndx; 4775 const Elf_Sym *symp; 4776 const char *strp; 4777 4778 symp = obj->symtab + symnum; 4779 strp = obj->strtab + symp->st_name; 4780 4781 switch (ELF_ST_TYPE(symp->st_info)) { 4782 case STT_FUNC: 4783 case STT_NOTYPE: 4784 case STT_OBJECT: 4785 case STT_COMMON: 4786 case STT_GNU_IFUNC: 4787 if (symp->st_value == 0) 4788 return (false); 4789 /* fallthrough */ 4790 case STT_TLS: 4791 if (symp->st_shndx != SHN_UNDEF) 4792 break; 4793 #ifndef __mips__ 4794 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4795 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4796 break; 4797 #endif 4798 /* fallthrough */ 4799 default: 4800 return (false); 4801 } 4802 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4803 return (false); 4804 4805 if (req->ventry == NULL) { 4806 if (obj->versyms != NULL) { 4807 verndx = VER_NDX(obj->versyms[symnum]); 4808 if (verndx > obj->vernum) { 4809 _rtld_error( 4810 "%s: symbol %s references wrong version %d", 4811 obj->path, obj->strtab + symnum, verndx); 4812 return (false); 4813 } 4814 /* 4815 * If we are not called from dlsym (i.e. this 4816 * is a normal relocation from unversioned 4817 * binary), accept the symbol immediately if 4818 * it happens to have first version after this 4819 * shared object became versioned. Otherwise, 4820 * if symbol is versioned and not hidden, 4821 * remember it. If it is the only symbol with 4822 * this name exported by the shared object, it 4823 * will be returned as a match by the calling 4824 * function. If symbol is global (verndx < 2) 4825 * accept it unconditionally. 4826 */ 4827 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4828 verndx == VER_NDX_GIVEN) { 4829 result->sym_out = symp; 4830 return (true); 4831 } 4832 else if (verndx >= VER_NDX_GIVEN) { 4833 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4834 == 0) { 4835 if (result->vsymp == NULL) 4836 result->vsymp = symp; 4837 result->vcount++; 4838 } 4839 return (false); 4840 } 4841 } 4842 result->sym_out = symp; 4843 return (true); 4844 } 4845 if (obj->versyms == NULL) { 4846 if (object_match_name(obj, req->ventry->name)) { 4847 _rtld_error("%s: object %s should provide version %s " 4848 "for symbol %s", obj_rtld.path, obj->path, 4849 req->ventry->name, obj->strtab + symnum); 4850 return (false); 4851 } 4852 } else { 4853 verndx = VER_NDX(obj->versyms[symnum]); 4854 if (verndx > obj->vernum) { 4855 _rtld_error("%s: symbol %s references wrong version %d", 4856 obj->path, obj->strtab + symnum, verndx); 4857 return (false); 4858 } 4859 if (obj->vertab[verndx].hash != req->ventry->hash || 4860 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4861 /* 4862 * Version does not match. Look if this is a 4863 * global symbol and if it is not hidden. If 4864 * global symbol (verndx < 2) is available, 4865 * use it. Do not return symbol if we are 4866 * called by dlvsym, because dlvsym looks for 4867 * a specific version and default one is not 4868 * what dlvsym wants. 4869 */ 4870 if ((req->flags & SYMLOOK_DLSYM) || 4871 (verndx >= VER_NDX_GIVEN) || 4872 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4873 return (false); 4874 } 4875 } 4876 result->sym_out = symp; 4877 return (true); 4878 } 4879 4880 /* 4881 * Search for symbol using SysV hash function. 4882 * obj->buckets is known not to be NULL at this point; the test for this was 4883 * performed with the obj->valid_hash_sysv assignment. 4884 */ 4885 static int 4886 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4887 { 4888 unsigned long symnum; 4889 Sym_Match_Result matchres; 4890 4891 matchres.sym_out = NULL; 4892 matchres.vsymp = NULL; 4893 matchres.vcount = 0; 4894 4895 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4896 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4897 if (symnum >= obj->nchains) 4898 return (ESRCH); /* Bad object */ 4899 4900 if (matched_symbol(req, obj, &matchres, symnum)) { 4901 req->sym_out = matchres.sym_out; 4902 req->defobj_out = obj; 4903 return (0); 4904 } 4905 } 4906 if (matchres.vcount == 1) { 4907 req->sym_out = matchres.vsymp; 4908 req->defobj_out = obj; 4909 return (0); 4910 } 4911 return (ESRCH); 4912 } 4913 4914 /* Search for symbol using GNU hash function */ 4915 static int 4916 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4917 { 4918 Elf_Addr bloom_word; 4919 const Elf32_Word *hashval; 4920 Elf32_Word bucket; 4921 Sym_Match_Result matchres; 4922 unsigned int h1, h2; 4923 unsigned long symnum; 4924 4925 matchres.sym_out = NULL; 4926 matchres.vsymp = NULL; 4927 matchres.vcount = 0; 4928 4929 /* Pick right bitmask word from Bloom filter array */ 4930 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4931 obj->maskwords_bm_gnu]; 4932 4933 /* Calculate modulus word size of gnu hash and its derivative */ 4934 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4935 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4936 4937 /* Filter out the "definitely not in set" queries */ 4938 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4939 return (ESRCH); 4940 4941 /* Locate hash chain and corresponding value element*/ 4942 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4943 if (bucket == 0) 4944 return (ESRCH); 4945 hashval = &obj->chain_zero_gnu[bucket]; 4946 do { 4947 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4948 symnum = hashval - obj->chain_zero_gnu; 4949 if (matched_symbol(req, obj, &matchres, symnum)) { 4950 req->sym_out = matchres.sym_out; 4951 req->defobj_out = obj; 4952 return (0); 4953 } 4954 } 4955 } while ((*hashval++ & 1) == 0); 4956 if (matchres.vcount == 1) { 4957 req->sym_out = matchres.vsymp; 4958 req->defobj_out = obj; 4959 return (0); 4960 } 4961 return (ESRCH); 4962 } 4963 4964 static void 4965 trace_loaded_objects(Obj_Entry *obj) 4966 { 4967 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4968 int c; 4969 4970 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4971 NULL) 4972 main_local = ""; 4973 4974 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4975 fmt1 = "\t%o => %p (%x)\n"; 4976 4977 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4978 fmt2 = "\t%o (%x)\n"; 4979 4980 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4981 4982 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4983 Needed_Entry *needed; 4984 const char *name, *path; 4985 bool is_lib; 4986 4987 if (obj->marker) 4988 continue; 4989 if (list_containers && obj->needed != NULL) 4990 rtld_printf("%s:\n", obj->path); 4991 for (needed = obj->needed; needed; needed = needed->next) { 4992 if (needed->obj != NULL) { 4993 if (needed->obj->traced && !list_containers) 4994 continue; 4995 needed->obj->traced = true; 4996 path = needed->obj->path; 4997 } else 4998 path = "not found"; 4999 5000 name = obj->strtab + needed->name; 5001 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 5002 5003 fmt = is_lib ? fmt1 : fmt2; 5004 while ((c = *fmt++) != '\0') { 5005 switch (c) { 5006 default: 5007 rtld_putchar(c); 5008 continue; 5009 case '\\': 5010 switch (c = *fmt) { 5011 case '\0': 5012 continue; 5013 case 'n': 5014 rtld_putchar('\n'); 5015 break; 5016 case 't': 5017 rtld_putchar('\t'); 5018 break; 5019 } 5020 break; 5021 case '%': 5022 switch (c = *fmt) { 5023 case '\0': 5024 continue; 5025 case '%': 5026 default: 5027 rtld_putchar(c); 5028 break; 5029 case 'A': 5030 rtld_putstr(main_local); 5031 break; 5032 case 'a': 5033 rtld_putstr(obj_main->path); 5034 break; 5035 case 'o': 5036 rtld_putstr(name); 5037 break; 5038 #if 0 5039 case 'm': 5040 rtld_printf("%d", sodp->sod_major); 5041 break; 5042 case 'n': 5043 rtld_printf("%d", sodp->sod_minor); 5044 break; 5045 #endif 5046 case 'p': 5047 rtld_putstr(path); 5048 break; 5049 case 'x': 5050 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 5051 0); 5052 break; 5053 } 5054 break; 5055 } 5056 ++fmt; 5057 } 5058 } 5059 } 5060 } 5061 5062 /* 5063 * Unload a dlopened object and its dependencies from memory and from 5064 * our data structures. It is assumed that the DAG rooted in the 5065 * object has already been unreferenced, and that the object has a 5066 * reference count of 0. 5067 */ 5068 static void 5069 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5070 { 5071 Obj_Entry marker, *obj, *next; 5072 5073 assert(root->refcount == 0); 5074 5075 /* 5076 * Pass over the DAG removing unreferenced objects from 5077 * appropriate lists. 5078 */ 5079 unlink_object(root); 5080 5081 /* Unmap all objects that are no longer referenced. */ 5082 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5083 next = TAILQ_NEXT(obj, next); 5084 if (obj->marker || obj->refcount != 0) 5085 continue; 5086 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5087 obj->mapsize, 0, obj->path); 5088 dbg("unloading \"%s\"", obj->path); 5089 /* 5090 * Unlink the object now to prevent new references from 5091 * being acquired while the bind lock is dropped in 5092 * recursive dlclose() invocations. 5093 */ 5094 TAILQ_REMOVE(&obj_list, obj, next); 5095 obj_count--; 5096 5097 if (obj->filtees_loaded) { 5098 if (next != NULL) { 5099 init_marker(&marker); 5100 TAILQ_INSERT_BEFORE(next, &marker, next); 5101 unload_filtees(obj, lockstate); 5102 next = TAILQ_NEXT(&marker, next); 5103 TAILQ_REMOVE(&obj_list, &marker, next); 5104 } else 5105 unload_filtees(obj, lockstate); 5106 } 5107 release_object(obj); 5108 } 5109 } 5110 5111 static void 5112 unlink_object(Obj_Entry *root) 5113 { 5114 Objlist_Entry *elm; 5115 5116 if (root->refcount == 0) { 5117 /* Remove the object from the RTLD_GLOBAL list. */ 5118 objlist_remove(&list_global, root); 5119 5120 /* Remove the object from all objects' DAG lists. */ 5121 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5122 objlist_remove(&elm->obj->dldags, root); 5123 if (elm->obj != root) 5124 unlink_object(elm->obj); 5125 } 5126 } 5127 } 5128 5129 static void 5130 ref_dag(Obj_Entry *root) 5131 { 5132 Objlist_Entry *elm; 5133 5134 assert(root->dag_inited); 5135 STAILQ_FOREACH(elm, &root->dagmembers, link) 5136 elm->obj->refcount++; 5137 } 5138 5139 static void 5140 unref_dag(Obj_Entry *root) 5141 { 5142 Objlist_Entry *elm; 5143 5144 assert(root->dag_inited); 5145 STAILQ_FOREACH(elm, &root->dagmembers, link) 5146 elm->obj->refcount--; 5147 } 5148 5149 /* 5150 * Common code for MD __tls_get_addr(). 5151 */ 5152 static void * 5153 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5154 { 5155 Elf_Addr *newdtv, *dtv; 5156 RtldLockState lockstate; 5157 int to_copy; 5158 5159 dtv = *dtvp; 5160 /* Check dtv generation in case new modules have arrived */ 5161 if (dtv[0] != tls_dtv_generation) { 5162 if (!locked) 5163 wlock_acquire(rtld_bind_lock, &lockstate); 5164 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5165 to_copy = dtv[1]; 5166 if (to_copy > tls_max_index) 5167 to_copy = tls_max_index; 5168 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5169 newdtv[0] = tls_dtv_generation; 5170 newdtv[1] = tls_max_index; 5171 free(dtv); 5172 if (!locked) 5173 lock_release(rtld_bind_lock, &lockstate); 5174 dtv = *dtvp = newdtv; 5175 } 5176 5177 /* Dynamically allocate module TLS if necessary */ 5178 if (dtv[index + 1] == 0) { 5179 /* Signal safe, wlock will block out signals. */ 5180 if (!locked) 5181 wlock_acquire(rtld_bind_lock, &lockstate); 5182 if (!dtv[index + 1]) 5183 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5184 if (!locked) 5185 lock_release(rtld_bind_lock, &lockstate); 5186 } 5187 return ((void *)(dtv[index + 1] + offset)); 5188 } 5189 5190 void * 5191 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 5192 { 5193 Elf_Addr *dtv; 5194 5195 dtv = *dtvp; 5196 /* Check dtv generation in case new modules have arrived */ 5197 if (__predict_true(dtv[0] == tls_dtv_generation && 5198 dtv[index + 1] != 0)) 5199 return ((void *)(dtv[index + 1] + offset)); 5200 return (tls_get_addr_slow(dtvp, index, offset, false)); 5201 } 5202 5203 #ifdef TLS_VARIANT_I 5204 5205 /* 5206 * Return pointer to allocated TLS block 5207 */ 5208 static void * 5209 get_tls_block_ptr(void *tcb, size_t tcbsize) 5210 { 5211 size_t extra_size, post_size, pre_size, tls_block_size; 5212 size_t tls_init_align; 5213 5214 tls_init_align = MAX(obj_main->tlsalign, 1); 5215 5216 /* Compute fragments sizes. */ 5217 extra_size = tcbsize - TLS_TCB_SIZE; 5218 post_size = calculate_tls_post_size(tls_init_align); 5219 tls_block_size = tcbsize + post_size; 5220 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5221 5222 return ((char *)tcb - pre_size - extra_size); 5223 } 5224 5225 /* 5226 * Allocate Static TLS using the Variant I method. 5227 * 5228 * For details on the layout, see lib/libc/gen/tls.c. 5229 * 5230 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5231 * it is based on tls_last_offset, and TLS offsets here are really TCB 5232 * offsets, whereas libc's tls_static_space is just the executable's static 5233 * TLS segment. 5234 */ 5235 void * 5236 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5237 { 5238 Obj_Entry *obj; 5239 char *tls_block; 5240 Elf_Addr *dtv, **tcb; 5241 Elf_Addr addr; 5242 Elf_Addr i; 5243 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5244 size_t tls_init_align, tls_init_offset; 5245 5246 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5247 return (oldtcb); 5248 5249 assert(tcbsize >= TLS_TCB_SIZE); 5250 maxalign = MAX(tcbalign, tls_static_max_align); 5251 tls_init_align = MAX(obj_main->tlsalign, 1); 5252 5253 /* Compute fragmets sizes. */ 5254 extra_size = tcbsize - TLS_TCB_SIZE; 5255 post_size = calculate_tls_post_size(tls_init_align); 5256 tls_block_size = tcbsize + post_size; 5257 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5258 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5259 5260 /* Allocate whole TLS block */ 5261 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5262 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5263 5264 if (oldtcb != NULL) { 5265 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5266 tls_static_space); 5267 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5268 5269 /* Adjust the DTV. */ 5270 dtv = tcb[0]; 5271 for (i = 0; i < dtv[1]; i++) { 5272 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5273 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5274 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5275 } 5276 } 5277 } else { 5278 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5279 tcb[0] = dtv; 5280 dtv[0] = tls_dtv_generation; 5281 dtv[1] = tls_max_index; 5282 5283 for (obj = globallist_curr(objs); obj != NULL; 5284 obj = globallist_next(obj)) { 5285 if (obj->tlsoffset == 0) 5286 continue; 5287 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5288 addr = (Elf_Addr)tcb + obj->tlsoffset; 5289 if (tls_init_offset > 0) 5290 memset((void *)addr, 0, tls_init_offset); 5291 if (obj->tlsinitsize > 0) { 5292 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5293 obj->tlsinitsize); 5294 } 5295 if (obj->tlssize > obj->tlsinitsize) { 5296 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5297 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5298 } 5299 dtv[obj->tlsindex + 1] = addr; 5300 } 5301 } 5302 5303 return (tcb); 5304 } 5305 5306 void 5307 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5308 { 5309 Elf_Addr *dtv; 5310 Elf_Addr tlsstart, tlsend; 5311 size_t post_size; 5312 size_t dtvsize, i, tls_init_align; 5313 5314 assert(tcbsize >= TLS_TCB_SIZE); 5315 tls_init_align = MAX(obj_main->tlsalign, 1); 5316 5317 /* Compute fragments sizes. */ 5318 post_size = calculate_tls_post_size(tls_init_align); 5319 5320 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5321 tlsend = (Elf_Addr)tcb + tls_static_space; 5322 5323 dtv = *(Elf_Addr **)tcb; 5324 dtvsize = dtv[1]; 5325 for (i = 0; i < dtvsize; i++) { 5326 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5327 free((void*)dtv[i+2]); 5328 } 5329 } 5330 free(dtv); 5331 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5332 } 5333 5334 #endif /* TLS_VARIANT_I */ 5335 5336 #ifdef TLS_VARIANT_II 5337 5338 /* 5339 * Allocate Static TLS using the Variant II method. 5340 */ 5341 void * 5342 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5343 { 5344 Obj_Entry *obj; 5345 size_t size, ralign; 5346 char *tls; 5347 Elf_Addr *dtv, *olddtv; 5348 Elf_Addr segbase, oldsegbase, addr; 5349 size_t i; 5350 5351 ralign = tcbalign; 5352 if (tls_static_max_align > ralign) 5353 ralign = tls_static_max_align; 5354 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5355 5356 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5357 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5358 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5359 5360 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5361 ((Elf_Addr *)segbase)[0] = segbase; 5362 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5363 5364 dtv[0] = tls_dtv_generation; 5365 dtv[1] = tls_max_index; 5366 5367 if (oldtls) { 5368 /* 5369 * Copy the static TLS block over whole. 5370 */ 5371 oldsegbase = (Elf_Addr) oldtls; 5372 memcpy((void *)(segbase - tls_static_space), 5373 (const void *)(oldsegbase - tls_static_space), 5374 tls_static_space); 5375 5376 /* 5377 * If any dynamic TLS blocks have been created tls_get_addr(), 5378 * move them over. 5379 */ 5380 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5381 for (i = 0; i < olddtv[1]; i++) { 5382 if (olddtv[i + 2] < oldsegbase - size || 5383 olddtv[i + 2] > oldsegbase) { 5384 dtv[i + 2] = olddtv[i + 2]; 5385 olddtv[i + 2] = 0; 5386 } 5387 } 5388 5389 /* 5390 * We assume that this block was the one we created with 5391 * allocate_initial_tls(). 5392 */ 5393 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5394 } else { 5395 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5396 if (obj->marker || obj->tlsoffset == 0) 5397 continue; 5398 addr = segbase - obj->tlsoffset; 5399 memset((void *)(addr + obj->tlsinitsize), 5400 0, obj->tlssize - obj->tlsinitsize); 5401 if (obj->tlsinit) { 5402 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5403 obj->static_tls_copied = true; 5404 } 5405 dtv[obj->tlsindex + 1] = addr; 5406 } 5407 } 5408 5409 return ((void *)segbase); 5410 } 5411 5412 void 5413 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5414 { 5415 Elf_Addr* dtv; 5416 size_t size, ralign; 5417 int dtvsize, i; 5418 Elf_Addr tlsstart, tlsend; 5419 5420 /* 5421 * Figure out the size of the initial TLS block so that we can 5422 * find stuff which ___tls_get_addr() allocated dynamically. 5423 */ 5424 ralign = tcbalign; 5425 if (tls_static_max_align > ralign) 5426 ralign = tls_static_max_align; 5427 size = roundup(tls_static_space, ralign); 5428 5429 dtv = ((Elf_Addr **)tls)[1]; 5430 dtvsize = dtv[1]; 5431 tlsend = (Elf_Addr)tls; 5432 tlsstart = tlsend - size; 5433 for (i = 0; i < dtvsize; i++) { 5434 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5435 dtv[i + 2] > tlsend)) { 5436 free_aligned((void *)dtv[i + 2]); 5437 } 5438 } 5439 5440 free_aligned((void *)tlsstart); 5441 free((void *)dtv); 5442 } 5443 5444 #endif /* TLS_VARIANT_II */ 5445 5446 /* 5447 * Allocate TLS block for module with given index. 5448 */ 5449 void * 5450 allocate_module_tls(int index) 5451 { 5452 Obj_Entry *obj; 5453 char *p; 5454 5455 TAILQ_FOREACH(obj, &obj_list, next) { 5456 if (obj->marker) 5457 continue; 5458 if (obj->tlsindex == index) 5459 break; 5460 } 5461 if (obj == NULL) { 5462 _rtld_error("Can't find module with TLS index %d", index); 5463 rtld_die(); 5464 } 5465 5466 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5467 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5468 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5469 return (p); 5470 } 5471 5472 bool 5473 allocate_tls_offset(Obj_Entry *obj) 5474 { 5475 size_t off; 5476 5477 if (obj->tls_done) 5478 return (true); 5479 5480 if (obj->tlssize == 0) { 5481 obj->tls_done = true; 5482 return (true); 5483 } 5484 5485 if (tls_last_offset == 0) 5486 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5487 obj->tlspoffset); 5488 else 5489 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5490 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5491 5492 obj->tlsoffset = off; 5493 #ifdef TLS_VARIANT_I 5494 off += obj->tlssize; 5495 #endif 5496 5497 /* 5498 * If we have already fixed the size of the static TLS block, we 5499 * must stay within that size. When allocating the static TLS, we 5500 * leave a small amount of space spare to be used for dynamically 5501 * loading modules which use static TLS. 5502 */ 5503 if (tls_static_space != 0) { 5504 if (off > tls_static_space) 5505 return (false); 5506 } else if (obj->tlsalign > tls_static_max_align) { 5507 tls_static_max_align = obj->tlsalign; 5508 } 5509 5510 tls_last_offset = off; 5511 tls_last_size = obj->tlssize; 5512 obj->tls_done = true; 5513 5514 return (true); 5515 } 5516 5517 void 5518 free_tls_offset(Obj_Entry *obj) 5519 { 5520 5521 /* 5522 * If we were the last thing to allocate out of the static TLS 5523 * block, we give our space back to the 'allocator'. This is a 5524 * simplistic workaround to allow libGL.so.1 to be loaded and 5525 * unloaded multiple times. 5526 */ 5527 size_t off = obj->tlsoffset; 5528 #ifdef TLS_VARIANT_I 5529 off += obj->tlssize; 5530 #endif 5531 if (off == tls_last_offset) { 5532 tls_last_offset -= obj->tlssize; 5533 tls_last_size = 0; 5534 } 5535 } 5536 5537 void * 5538 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5539 { 5540 void *ret; 5541 RtldLockState lockstate; 5542 5543 wlock_acquire(rtld_bind_lock, &lockstate); 5544 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5545 tcbsize, tcbalign); 5546 lock_release(rtld_bind_lock, &lockstate); 5547 return (ret); 5548 } 5549 5550 void 5551 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5552 { 5553 RtldLockState lockstate; 5554 5555 wlock_acquire(rtld_bind_lock, &lockstate); 5556 free_tls(tcb, tcbsize, tcbalign); 5557 lock_release(rtld_bind_lock, &lockstate); 5558 } 5559 5560 static void 5561 object_add_name(Obj_Entry *obj, const char *name) 5562 { 5563 Name_Entry *entry; 5564 size_t len; 5565 5566 len = strlen(name); 5567 entry = malloc(sizeof(Name_Entry) + len); 5568 5569 if (entry != NULL) { 5570 strcpy(entry->name, name); 5571 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5572 } 5573 } 5574 5575 static int 5576 object_match_name(const Obj_Entry *obj, const char *name) 5577 { 5578 Name_Entry *entry; 5579 5580 STAILQ_FOREACH(entry, &obj->names, link) { 5581 if (strcmp(name, entry->name) == 0) 5582 return (1); 5583 } 5584 return (0); 5585 } 5586 5587 static Obj_Entry * 5588 locate_dependency(const Obj_Entry *obj, const char *name) 5589 { 5590 const Objlist_Entry *entry; 5591 const Needed_Entry *needed; 5592 5593 STAILQ_FOREACH(entry, &list_main, link) { 5594 if (object_match_name(entry->obj, name)) 5595 return (entry->obj); 5596 } 5597 5598 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5599 if (strcmp(obj->strtab + needed->name, name) == 0 || 5600 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5601 /* 5602 * If there is DT_NEEDED for the name we are looking for, 5603 * we are all set. Note that object might not be found if 5604 * dependency was not loaded yet, so the function can 5605 * return NULL here. This is expected and handled 5606 * properly by the caller. 5607 */ 5608 return (needed->obj); 5609 } 5610 } 5611 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5612 obj->path, name); 5613 rtld_die(); 5614 } 5615 5616 static int 5617 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5618 const Elf_Vernaux *vna) 5619 { 5620 const Elf_Verdef *vd; 5621 const char *vername; 5622 5623 vername = refobj->strtab + vna->vna_name; 5624 vd = depobj->verdef; 5625 if (vd == NULL) { 5626 _rtld_error("%s: version %s required by %s not defined", 5627 depobj->path, vername, refobj->path); 5628 return (-1); 5629 } 5630 for (;;) { 5631 if (vd->vd_version != VER_DEF_CURRENT) { 5632 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5633 depobj->path, vd->vd_version); 5634 return (-1); 5635 } 5636 if (vna->vna_hash == vd->vd_hash) { 5637 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5638 ((const char *)vd + vd->vd_aux); 5639 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5640 return (0); 5641 } 5642 if (vd->vd_next == 0) 5643 break; 5644 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5645 } 5646 if (vna->vna_flags & VER_FLG_WEAK) 5647 return (0); 5648 _rtld_error("%s: version %s required by %s not found", 5649 depobj->path, vername, refobj->path); 5650 return (-1); 5651 } 5652 5653 static int 5654 rtld_verify_object_versions(Obj_Entry *obj) 5655 { 5656 const Elf_Verneed *vn; 5657 const Elf_Verdef *vd; 5658 const Elf_Verdaux *vda; 5659 const Elf_Vernaux *vna; 5660 const Obj_Entry *depobj; 5661 int maxvernum, vernum; 5662 5663 if (obj->ver_checked) 5664 return (0); 5665 obj->ver_checked = true; 5666 5667 maxvernum = 0; 5668 /* 5669 * Walk over defined and required version records and figure out 5670 * max index used by any of them. Do very basic sanity checking 5671 * while there. 5672 */ 5673 vn = obj->verneed; 5674 while (vn != NULL) { 5675 if (vn->vn_version != VER_NEED_CURRENT) { 5676 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5677 obj->path, vn->vn_version); 5678 return (-1); 5679 } 5680 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5681 for (;;) { 5682 vernum = VER_NEED_IDX(vna->vna_other); 5683 if (vernum > maxvernum) 5684 maxvernum = vernum; 5685 if (vna->vna_next == 0) 5686 break; 5687 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5688 } 5689 if (vn->vn_next == 0) 5690 break; 5691 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5692 } 5693 5694 vd = obj->verdef; 5695 while (vd != NULL) { 5696 if (vd->vd_version != VER_DEF_CURRENT) { 5697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5698 obj->path, vd->vd_version); 5699 return (-1); 5700 } 5701 vernum = VER_DEF_IDX(vd->vd_ndx); 5702 if (vernum > maxvernum) 5703 maxvernum = vernum; 5704 if (vd->vd_next == 0) 5705 break; 5706 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5707 } 5708 5709 if (maxvernum == 0) 5710 return (0); 5711 5712 /* 5713 * Store version information in array indexable by version index. 5714 * Verify that object version requirements are satisfied along the 5715 * way. 5716 */ 5717 obj->vernum = maxvernum + 1; 5718 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5719 5720 vd = obj->verdef; 5721 while (vd != NULL) { 5722 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5723 vernum = VER_DEF_IDX(vd->vd_ndx); 5724 assert(vernum <= maxvernum); 5725 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5726 obj->vertab[vernum].hash = vd->vd_hash; 5727 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5728 obj->vertab[vernum].file = NULL; 5729 obj->vertab[vernum].flags = 0; 5730 } 5731 if (vd->vd_next == 0) 5732 break; 5733 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5734 } 5735 5736 vn = obj->verneed; 5737 while (vn != NULL) { 5738 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5739 if (depobj == NULL) 5740 return (-1); 5741 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5742 for (;;) { 5743 if (check_object_provided_version(obj, depobj, vna)) 5744 return (-1); 5745 vernum = VER_NEED_IDX(vna->vna_other); 5746 assert(vernum <= maxvernum); 5747 obj->vertab[vernum].hash = vna->vna_hash; 5748 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5749 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5750 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5751 VER_INFO_HIDDEN : 0; 5752 if (vna->vna_next == 0) 5753 break; 5754 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5755 } 5756 if (vn->vn_next == 0) 5757 break; 5758 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5759 } 5760 return (0); 5761 } 5762 5763 static int 5764 rtld_verify_versions(const Objlist *objlist) 5765 { 5766 Objlist_Entry *entry; 5767 int rc; 5768 5769 rc = 0; 5770 STAILQ_FOREACH(entry, objlist, link) { 5771 /* 5772 * Skip dummy objects or objects that have their version requirements 5773 * already checked. 5774 */ 5775 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5776 continue; 5777 if (rtld_verify_object_versions(entry->obj) == -1) { 5778 rc = -1; 5779 if (ld_tracing == NULL) 5780 break; 5781 } 5782 } 5783 if (rc == 0 || ld_tracing != NULL) 5784 rc = rtld_verify_object_versions(&obj_rtld); 5785 return (rc); 5786 } 5787 5788 const Ver_Entry * 5789 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5790 { 5791 Elf_Versym vernum; 5792 5793 if (obj->vertab) { 5794 vernum = VER_NDX(obj->versyms[symnum]); 5795 if (vernum >= obj->vernum) { 5796 _rtld_error("%s: symbol %s has wrong verneed value %d", 5797 obj->path, obj->strtab + symnum, vernum); 5798 } else if (obj->vertab[vernum].hash != 0) { 5799 return (&obj->vertab[vernum]); 5800 } 5801 } 5802 return (NULL); 5803 } 5804 5805 int 5806 _rtld_get_stack_prot(void) 5807 { 5808 5809 return (stack_prot); 5810 } 5811 5812 int 5813 _rtld_is_dlopened(void *arg) 5814 { 5815 Obj_Entry *obj; 5816 RtldLockState lockstate; 5817 int res; 5818 5819 rlock_acquire(rtld_bind_lock, &lockstate); 5820 obj = dlcheck(arg); 5821 if (obj == NULL) 5822 obj = obj_from_addr(arg); 5823 if (obj == NULL) { 5824 _rtld_error("No shared object contains address"); 5825 lock_release(rtld_bind_lock, &lockstate); 5826 return (-1); 5827 } 5828 res = obj->dlopened ? 1 : 0; 5829 lock_release(rtld_bind_lock, &lockstate); 5830 return (res); 5831 } 5832 5833 static int 5834 obj_remap_relro(Obj_Entry *obj, int prot) 5835 { 5836 5837 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5838 prot) == -1) { 5839 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5840 obj->path, prot, rtld_strerror(errno)); 5841 return (-1); 5842 } 5843 return (0); 5844 } 5845 5846 static int 5847 obj_disable_relro(Obj_Entry *obj) 5848 { 5849 5850 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5851 } 5852 5853 static int 5854 obj_enforce_relro(Obj_Entry *obj) 5855 { 5856 5857 return (obj_remap_relro(obj, PROT_READ)); 5858 } 5859 5860 static void 5861 map_stacks_exec(RtldLockState *lockstate) 5862 { 5863 void (*thr_map_stacks_exec)(void); 5864 5865 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5866 return; 5867 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5868 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5869 if (thr_map_stacks_exec != NULL) { 5870 stack_prot |= PROT_EXEC; 5871 thr_map_stacks_exec(); 5872 } 5873 } 5874 5875 static void 5876 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5877 { 5878 Objlist_Entry *elm; 5879 Obj_Entry *obj; 5880 void (*distrib)(size_t, void *, size_t, size_t); 5881 5882 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5883 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5884 if (distrib == NULL) 5885 return; 5886 STAILQ_FOREACH(elm, list, link) { 5887 obj = elm->obj; 5888 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5889 continue; 5890 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5891 obj->tlssize); 5892 obj->static_tls_copied = true; 5893 } 5894 } 5895 5896 void 5897 symlook_init(SymLook *dst, const char *name) 5898 { 5899 5900 bzero(dst, sizeof(*dst)); 5901 dst->name = name; 5902 dst->hash = elf_hash(name); 5903 dst->hash_gnu = gnu_hash(name); 5904 } 5905 5906 static void 5907 symlook_init_from_req(SymLook *dst, const SymLook *src) 5908 { 5909 5910 dst->name = src->name; 5911 dst->hash = src->hash; 5912 dst->hash_gnu = src->hash_gnu; 5913 dst->ventry = src->ventry; 5914 dst->flags = src->flags; 5915 dst->defobj_out = NULL; 5916 dst->sym_out = NULL; 5917 dst->lockstate = src->lockstate; 5918 } 5919 5920 static int 5921 open_binary_fd(const char *argv0, bool search_in_path, 5922 const char **binpath_res) 5923 { 5924 char *binpath, *pathenv, *pe, *res1; 5925 const char *res; 5926 int fd; 5927 5928 binpath = NULL; 5929 res = NULL; 5930 if (search_in_path && strchr(argv0, '/') == NULL) { 5931 binpath = xmalloc(PATH_MAX); 5932 pathenv = getenv("PATH"); 5933 if (pathenv == NULL) { 5934 _rtld_error("-p and no PATH environment variable"); 5935 rtld_die(); 5936 } 5937 pathenv = strdup(pathenv); 5938 if (pathenv == NULL) { 5939 _rtld_error("Cannot allocate memory"); 5940 rtld_die(); 5941 } 5942 fd = -1; 5943 errno = ENOENT; 5944 while ((pe = strsep(&pathenv, ":")) != NULL) { 5945 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5946 continue; 5947 if (binpath[0] != '\0' && 5948 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5949 continue; 5950 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5951 continue; 5952 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5953 if (fd != -1 || errno != ENOENT) { 5954 res = binpath; 5955 break; 5956 } 5957 } 5958 free(pathenv); 5959 } else { 5960 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5961 res = argv0; 5962 } 5963 5964 if (fd == -1) { 5965 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5966 rtld_die(); 5967 } 5968 if (res != NULL && res[0] != '/') { 5969 res1 = xmalloc(PATH_MAX); 5970 if (realpath(res, res1) != NULL) { 5971 if (res != argv0) 5972 free(__DECONST(char *, res)); 5973 res = res1; 5974 } else { 5975 free(res1); 5976 } 5977 } 5978 *binpath_res = res; 5979 return (fd); 5980 } 5981 5982 /* 5983 * Parse a set of command-line arguments. 5984 */ 5985 static int 5986 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5987 const char **argv0, bool *dir_ignore) 5988 { 5989 const char *arg; 5990 char machine[64]; 5991 size_t sz; 5992 int arglen, fd, i, j, mib[2]; 5993 char opt; 5994 bool seen_b, seen_f; 5995 5996 dbg("Parsing command-line arguments"); 5997 *use_pathp = false; 5998 *fdp = -1; 5999 *dir_ignore = false; 6000 seen_b = seen_f = false; 6001 6002 for (i = 1; i < argc; i++ ) { 6003 arg = argv[i]; 6004 dbg("argv[%d]: '%s'", i, arg); 6005 6006 /* 6007 * rtld arguments end with an explicit "--" or with the first 6008 * non-prefixed argument. 6009 */ 6010 if (strcmp(arg, "--") == 0) { 6011 i++; 6012 break; 6013 } 6014 if (arg[0] != '-') 6015 break; 6016 6017 /* 6018 * All other arguments are single-character options that can 6019 * be combined, so we need to search through `arg` for them. 6020 */ 6021 arglen = strlen(arg); 6022 for (j = 1; j < arglen; j++) { 6023 opt = arg[j]; 6024 if (opt == 'h') { 6025 print_usage(argv[0]); 6026 _exit(0); 6027 } else if (opt == 'b') { 6028 if (seen_f) { 6029 _rtld_error("Both -b and -f specified"); 6030 rtld_die(); 6031 } 6032 i++; 6033 *argv0 = argv[i]; 6034 seen_b = true; 6035 break; 6036 } else if (opt == 'd') { 6037 *dir_ignore = true; 6038 break; 6039 } else if (opt == 'f') { 6040 if (seen_b) { 6041 _rtld_error("Both -b and -f specified"); 6042 rtld_die(); 6043 } 6044 6045 /* 6046 * -f XX can be used to specify a 6047 * descriptor for the binary named at 6048 * the command line (i.e., the later 6049 * argument will specify the process 6050 * name but the descriptor is what 6051 * will actually be executed). 6052 * 6053 * -f must be the last option in, e.g., -abcf. 6054 */ 6055 if (j != arglen - 1) { 6056 _rtld_error("Invalid options: %s", arg); 6057 rtld_die(); 6058 } 6059 i++; 6060 fd = parse_integer(argv[i]); 6061 if (fd == -1) { 6062 _rtld_error( 6063 "Invalid file descriptor: '%s'", 6064 argv[i]); 6065 rtld_die(); 6066 } 6067 *fdp = fd; 6068 seen_f = true; 6069 break; 6070 } else if (opt == 'p') { 6071 *use_pathp = true; 6072 } else if (opt == 'u') { 6073 trust = false; 6074 } else if (opt == 'v') { 6075 machine[0] = '\0'; 6076 mib[0] = CTL_HW; 6077 mib[1] = HW_MACHINE; 6078 sz = sizeof(machine); 6079 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6080 ld_elf_hints_path = ld_get_env_var( 6081 LD_ELF_HINTS_PATH); 6082 set_ld_elf_hints_path(); 6083 rtld_printf( 6084 "FreeBSD ld-elf.so.1 %s\n" 6085 "FreeBSD_version %d\n" 6086 "Default lib path %s\n" 6087 "Hints lib path %s\n" 6088 "Env prefix %s\n" 6089 "Default hint file %s\n" 6090 "Hint file %s\n" 6091 "libmap file %s\n", 6092 machine, 6093 __FreeBSD_version, ld_standard_library_path, 6094 gethints(false), 6095 ld_env_prefix, ld_elf_hints_default, 6096 ld_elf_hints_path, 6097 ld_path_libmap_conf); 6098 _exit(0); 6099 } else { 6100 _rtld_error("Invalid argument: '%s'", arg); 6101 print_usage(argv[0]); 6102 rtld_die(); 6103 } 6104 } 6105 } 6106 6107 if (!seen_b) 6108 *argv0 = argv[i]; 6109 return (i); 6110 } 6111 6112 /* 6113 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6114 */ 6115 static int 6116 parse_integer(const char *str) 6117 { 6118 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6119 const char *orig; 6120 int n; 6121 char c; 6122 6123 orig = str; 6124 n = 0; 6125 for (c = *str; c != '\0'; c = *++str) { 6126 if (c < '0' || c > '9') 6127 return (-1); 6128 6129 n *= RADIX; 6130 n += c - '0'; 6131 } 6132 6133 /* Make sure we actually parsed something. */ 6134 if (str == orig) 6135 return (-1); 6136 return (n); 6137 } 6138 6139 static void 6140 print_usage(const char *argv0) 6141 { 6142 6143 rtld_printf( 6144 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6145 "\n" 6146 "Options:\n" 6147 " -h Display this help message\n" 6148 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6149 " -d Ignore lack of exec permissions for the binary\n" 6150 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6151 " -p Search in PATH for named binary\n" 6152 " -u Ignore LD_ environment variables\n" 6153 " -v Display identification information\n" 6154 " -- End of RTLD options\n" 6155 " <binary> Name of process to execute\n" 6156 " <args> Arguments to the executed process\n", argv0); 6157 } 6158 6159 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6160 static const struct auxfmt { 6161 const char *name; 6162 const char *fmt; 6163 } auxfmts[] = { 6164 AUXFMT(AT_NULL, NULL), 6165 AUXFMT(AT_IGNORE, NULL), 6166 AUXFMT(AT_EXECFD, "%ld"), 6167 AUXFMT(AT_PHDR, "%p"), 6168 AUXFMT(AT_PHENT, "%lu"), 6169 AUXFMT(AT_PHNUM, "%lu"), 6170 AUXFMT(AT_PAGESZ, "%lu"), 6171 AUXFMT(AT_BASE, "%#lx"), 6172 AUXFMT(AT_FLAGS, "%#lx"), 6173 AUXFMT(AT_ENTRY, "%p"), 6174 AUXFMT(AT_NOTELF, NULL), 6175 AUXFMT(AT_UID, "%ld"), 6176 AUXFMT(AT_EUID, "%ld"), 6177 AUXFMT(AT_GID, "%ld"), 6178 AUXFMT(AT_EGID, "%ld"), 6179 AUXFMT(AT_EXECPATH, "%s"), 6180 AUXFMT(AT_CANARY, "%p"), 6181 AUXFMT(AT_CANARYLEN, "%lu"), 6182 AUXFMT(AT_OSRELDATE, "%lu"), 6183 AUXFMT(AT_NCPUS, "%lu"), 6184 AUXFMT(AT_PAGESIZES, "%p"), 6185 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6186 AUXFMT(AT_TIMEKEEP, "%p"), 6187 AUXFMT(AT_STACKPROT, "%#lx"), 6188 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6189 AUXFMT(AT_HWCAP, "%#lx"), 6190 AUXFMT(AT_HWCAP2, "%#lx"), 6191 AUXFMT(AT_BSDFLAGS, "%#lx"), 6192 AUXFMT(AT_ARGC, "%lu"), 6193 AUXFMT(AT_ARGV, "%p"), 6194 AUXFMT(AT_ENVC, "%p"), 6195 AUXFMT(AT_ENVV, "%p"), 6196 AUXFMT(AT_PS_STRINGS, "%p"), 6197 AUXFMT(AT_FXRNG, "%p"), 6198 AUXFMT(AT_KPRELOAD, "%p"), 6199 }; 6200 6201 static bool 6202 is_ptr_fmt(const char *fmt) 6203 { 6204 char last; 6205 6206 last = fmt[strlen(fmt) - 1]; 6207 return (last == 'p' || last == 's'); 6208 } 6209 6210 static void 6211 dump_auxv(Elf_Auxinfo **aux_info) 6212 { 6213 Elf_Auxinfo *auxp; 6214 const struct auxfmt *fmt; 6215 int i; 6216 6217 for (i = 0; i < AT_COUNT; i++) { 6218 auxp = aux_info[i]; 6219 if (auxp == NULL) 6220 continue; 6221 fmt = &auxfmts[i]; 6222 if (fmt->fmt == NULL) 6223 continue; 6224 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6225 if (is_ptr_fmt(fmt->fmt)) { 6226 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6227 auxp->a_un.a_ptr); 6228 } else { 6229 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6230 auxp->a_un.a_val); 6231 } 6232 rtld_fdprintf(STDOUT_FILENO, "\n"); 6233 } 6234 } 6235 6236 /* 6237 * Overrides for libc_pic-provided functions. 6238 */ 6239 6240 int 6241 __getosreldate(void) 6242 { 6243 size_t len; 6244 int oid[2]; 6245 int error, osrel; 6246 6247 if (osreldate != 0) 6248 return (osreldate); 6249 6250 oid[0] = CTL_KERN; 6251 oid[1] = KERN_OSRELDATE; 6252 osrel = 0; 6253 len = sizeof(osrel); 6254 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6255 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6256 osreldate = osrel; 6257 return (osreldate); 6258 } 6259 const char * 6260 rtld_strerror(int errnum) 6261 { 6262 6263 if (errnum < 0 || errnum >= sys_nerr) 6264 return ("Unknown error"); 6265 return (sys_errlist[errnum]); 6266 } 6267 6268 char * 6269 getenv(const char *name) 6270 { 6271 return (__DECONST(char *, rtld_get_env_val(environ, name, 6272 strlen(name)))); 6273 } 6274 6275 /* malloc */ 6276 void * 6277 malloc(size_t nbytes) 6278 { 6279 6280 return (__crt_malloc(nbytes)); 6281 } 6282 6283 void * 6284 calloc(size_t num, size_t size) 6285 { 6286 6287 return (__crt_calloc(num, size)); 6288 } 6289 6290 void 6291 free(void *cp) 6292 { 6293 6294 __crt_free(cp); 6295 } 6296 6297 void * 6298 realloc(void *cp, size_t nbytes) 6299 { 6300 6301 return (__crt_realloc(cp, nbytes)); 6302 } 6303 6304 extern int _rtld_version__FreeBSD_version __exported; 6305 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6306 6307 extern char _rtld_version_laddr_offset __exported; 6308 char _rtld_version_laddr_offset; 6309 6310 extern char _rtld_version_dlpi_tls_data __exported; 6311 char _rtld_version_dlpi_tls_data; 6312