1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 #include <sys/param.h> 43 #include <sys/mount.h> 44 #include <sys/mman.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/uio.h> 48 #include <sys/utsname.h> 49 #include <sys/ktrace.h> 50 51 #include <dlfcn.h> 52 #include <err.h> 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <stdarg.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 #include "debug.h" 62 #include "rtld.h" 63 #include "libmap.h" 64 #include "rtld_paths.h" 65 #include "rtld_tls.h" 66 #include "rtld_printf.h" 67 #include "rtld_malloc.h" 68 #include "rtld_utrace.h" 69 #include "notes.h" 70 #include "rtld_libc.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(void); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 77 /* Variables that cannot be static: */ 78 extern struct r_debug r_debug; /* For GDB */ 79 extern int _thread_autoinit_dummy_decl; 80 extern void (*__cleanup)(void); 81 82 struct dlerror_save { 83 int seen; 84 char *msg; 85 }; 86 87 /* 88 * Function declarations. 89 */ 90 static const char *basename(const char *); 91 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 92 const Elf_Dyn **, const Elf_Dyn **); 93 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 94 const Elf_Dyn *); 95 static bool digest_dynamic(Obj_Entry *, int); 96 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 97 static void distribute_static_tls(Objlist *, RtldLockState *); 98 static Obj_Entry *dlcheck(void *); 99 static int dlclose_locked(void *, RtldLockState *); 100 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 101 int lo_flags, int mode, RtldLockState *lockstate); 102 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 103 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 104 static bool donelist_check(DoneList *, const Obj_Entry *); 105 static void dump_auxv(Elf_Auxinfo **aux_info); 106 static void errmsg_restore(struct dlerror_save *); 107 static struct dlerror_save *errmsg_save(void); 108 static void *fill_search_info(const char *, size_t, void *); 109 static char *find_library(const char *, const Obj_Entry *, int *); 110 static const char *gethints(bool); 111 static void hold_object(Obj_Entry *); 112 static void unhold_object(Obj_Entry *); 113 static void init_dag(Obj_Entry *); 114 static void init_marker(Obj_Entry *); 115 static void init_pagesizes(Elf_Auxinfo **aux_info); 116 static void init_rtld(caddr_t, Elf_Auxinfo **); 117 static void initlist_add_neededs(Needed_Entry *, Objlist *); 118 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 119 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 120 static void linkmap_add(Obj_Entry *); 121 static void linkmap_delete(Obj_Entry *); 122 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 123 static void unload_filtees(Obj_Entry *, RtldLockState *); 124 static int load_needed_objects(Obj_Entry *, int); 125 static int load_preload_objects(const char *, bool); 126 static int load_kpreload(const void *addr); 127 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 128 static void map_stacks_exec(RtldLockState *); 129 static int obj_disable_relro(Obj_Entry *); 130 static int obj_enforce_relro(Obj_Entry *); 131 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 132 static void objlist_call_init(Objlist *, RtldLockState *); 133 static void objlist_clear(Objlist *); 134 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 135 static void objlist_init(Objlist *); 136 static void objlist_push_head(Objlist *, Obj_Entry *); 137 static void objlist_push_tail(Objlist *, Obj_Entry *); 138 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 139 static void objlist_remove(Objlist *, Obj_Entry *); 140 static int open_binary_fd(const char *argv0, bool search_in_path, 141 const char **binpath_res); 142 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 143 const char **argv0, bool *dir_ignore); 144 static int parse_integer(const char *); 145 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 146 static void print_usage(const char *argv0); 147 static void release_object(Obj_Entry *); 148 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 149 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 150 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 151 int flags, RtldLockState *lockstate); 152 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 153 RtldLockState *); 154 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 155 static int rtld_dirname(const char *, char *); 156 static int rtld_dirname_abs(const char *, char *); 157 static void *rtld_dlopen(const char *name, int fd, int mode); 158 static void rtld_exit(void); 159 static void rtld_nop_exit(void); 160 static char *search_library_path(const char *, const char *, const char *, 161 int *); 162 static char *search_library_pathfds(const char *, const char *, int *); 163 static const void **get_program_var_addr(const char *, RtldLockState *); 164 static void set_program_var(const char *, const void *); 165 static int symlook_default(SymLook *, const Obj_Entry *refobj); 166 static int symlook_global(SymLook *, DoneList *); 167 static void symlook_init_from_req(SymLook *, const SymLook *); 168 static int symlook_list(SymLook *, const Objlist *, DoneList *); 169 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 170 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 171 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 172 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 173 static void trace_loaded_objects(Obj_Entry *, bool); 174 static void unlink_object(Obj_Entry *); 175 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 176 static void unref_dag(Obj_Entry *); 177 static void ref_dag(Obj_Entry *); 178 static char *origin_subst_one(Obj_Entry *, char *, const char *, 179 const char *, bool); 180 static char *origin_subst(Obj_Entry *, const char *); 181 static bool obj_resolve_origin(Obj_Entry *obj); 182 static void preinit_main(void); 183 static int rtld_verify_versions(const Objlist *); 184 static int rtld_verify_object_versions(Obj_Entry *); 185 static void object_add_name(Obj_Entry *, const char *); 186 static int object_match_name(const Obj_Entry *, const char *); 187 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 188 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 189 struct dl_phdr_info *phdr_info); 190 static uint32_t gnu_hash(const char *); 191 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 192 const unsigned long); 193 194 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 195 void _r_debug_postinit(struct link_map *) __noinline __exported; 196 197 int __sys_openat(int, const char *, int, ...); 198 199 /* 200 * Data declarations. 201 */ 202 struct r_debug r_debug __exported; /* for GDB; */ 203 static bool libmap_disable; /* Disable libmap */ 204 static bool ld_loadfltr; /* Immediate filters processing */ 205 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 206 static bool trust; /* False for setuid and setgid programs */ 207 static bool dangerous_ld_env; /* True if environment variables have been 208 used to affect the libraries loaded */ 209 bool ld_bind_not; /* Disable PLT update */ 210 static const char *ld_bind_now; /* Environment variable for immediate binding */ 211 static const char *ld_debug; /* Environment variable for debugging */ 212 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 213 weak definition */ 214 static const char *ld_library_path;/* Environment variable for search path */ 215 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 216 static const char *ld_preload; /* Environment variable for libraries to 217 load first */ 218 static const char *ld_preload_fds;/* Environment variable for libraries represented by 219 descriptors */ 220 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 221 static const char *ld_tracing; /* Called from ldd to print libs */ 222 static const char *ld_utrace; /* Use utrace() to log events. */ 223 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 224 static Obj_Entry *obj_main; /* The main program shared object */ 225 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 226 static unsigned int obj_count; /* Number of objects in obj_list */ 227 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 228 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */ 229 RTLD_STATIC_TLS_EXTRA; 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 int npagesizes; 268 static int osreldate; 269 size_t *pagesizes; 270 size_t page_size; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 enum { 348 LD_BIND_NOW = 0, 349 LD_PRELOAD, 350 LD_LIBMAP, 351 LD_LIBRARY_PATH, 352 LD_LIBRARY_PATH_FDS, 353 LD_LIBMAP_DISABLE, 354 LD_BIND_NOT, 355 LD_DEBUG, 356 LD_ELF_HINTS_PATH, 357 LD_LOADFLTR, 358 LD_LIBRARY_PATH_RPATH, 359 LD_PRELOAD_FDS, 360 LD_DYNAMIC_WEAK, 361 LD_TRACE_LOADED_OBJECTS, 362 LD_UTRACE, 363 LD_DUMP_REL_PRE, 364 LD_DUMP_REL_POST, 365 LD_TRACE_LOADED_OBJECTS_PROGNAME, 366 LD_TRACE_LOADED_OBJECTS_FMT1, 367 LD_TRACE_LOADED_OBJECTS_FMT2, 368 LD_TRACE_LOADED_OBJECTS_ALL, 369 LD_SHOW_AUXV, 370 LD_STATIC_TLS_EXTRA, 371 }; 372 373 struct ld_env_var_desc { 374 const char * const n; 375 const char *val; 376 const bool unsecure; 377 }; 378 #define LD_ENV_DESC(var, unsec) \ 379 [LD_##var] = { .n = #var, .unsecure = unsec } 380 381 static struct ld_env_var_desc ld_env_vars[] = { 382 LD_ENV_DESC(BIND_NOW, false), 383 LD_ENV_DESC(PRELOAD, true), 384 LD_ENV_DESC(LIBMAP, true), 385 LD_ENV_DESC(LIBRARY_PATH, true), 386 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 387 LD_ENV_DESC(LIBMAP_DISABLE, true), 388 LD_ENV_DESC(BIND_NOT, true), 389 LD_ENV_DESC(DEBUG, true), 390 LD_ENV_DESC(ELF_HINTS_PATH, true), 391 LD_ENV_DESC(LOADFLTR, true), 392 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 393 LD_ENV_DESC(PRELOAD_FDS, true), 394 LD_ENV_DESC(DYNAMIC_WEAK, true), 395 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 396 LD_ENV_DESC(UTRACE, false), 397 LD_ENV_DESC(DUMP_REL_PRE, false), 398 LD_ENV_DESC(DUMP_REL_POST, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 402 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 403 LD_ENV_DESC(SHOW_AUXV, false), 404 LD_ENV_DESC(STATIC_TLS_EXTRA, false), 405 }; 406 407 static const char * 408 ld_get_env_var(int idx) 409 { 410 return (ld_env_vars[idx].val); 411 } 412 413 static const char * 414 rtld_get_env_val(char **env, const char *name, size_t name_len) 415 { 416 char **m, *n, *v; 417 418 for (m = env; *m != NULL; m++) { 419 n = *m; 420 v = strchr(n, '='); 421 if (v == NULL) { 422 /* corrupt environment? */ 423 continue; 424 } 425 if (v - n == (ptrdiff_t)name_len && 426 strncmp(name, n, name_len) == 0) 427 return (v + 1); 428 } 429 return (NULL); 430 } 431 432 static void 433 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 434 { 435 struct ld_env_var_desc *lvd; 436 size_t prefix_len, nlen; 437 char **m, *n, *v; 438 int i; 439 440 prefix_len = strlen(env_prefix); 441 for (m = env; *m != NULL; m++) { 442 n = *m; 443 if (strncmp(env_prefix, n, prefix_len) != 0) { 444 /* Not a rtld environment variable. */ 445 continue; 446 } 447 n += prefix_len; 448 v = strchr(n, '='); 449 if (v == NULL) { 450 /* corrupt environment? */ 451 continue; 452 } 453 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 454 lvd = &ld_env_vars[i]; 455 if (lvd->val != NULL) { 456 /* Saw higher-priority variable name already. */ 457 continue; 458 } 459 nlen = strlen(lvd->n); 460 if (v - n == (ptrdiff_t)nlen && 461 strncmp(lvd->n, n, nlen) == 0) { 462 lvd->val = v + 1; 463 break; 464 } 465 } 466 } 467 } 468 469 static void 470 rtld_init_env_vars(char **env) 471 { 472 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 473 } 474 475 static void 476 set_ld_elf_hints_path(void) 477 { 478 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 479 ld_elf_hints_path = ld_elf_hints_default; 480 } 481 482 uintptr_t 483 rtld_round_page(uintptr_t x) 484 { 485 return (roundup2(x, page_size)); 486 } 487 488 uintptr_t 489 rtld_trunc_page(uintptr_t x) 490 { 491 return (rounddown2(x, page_size)); 492 } 493 494 /* 495 * Main entry point for dynamic linking. The first argument is the 496 * stack pointer. The stack is expected to be laid out as described 497 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 498 * Specifically, the stack pointer points to a word containing 499 * ARGC. Following that in the stack is a null-terminated sequence 500 * of pointers to argument strings. Then comes a null-terminated 501 * sequence of pointers to environment strings. Finally, there is a 502 * sequence of "auxiliary vector" entries. 503 * 504 * The second argument points to a place to store the dynamic linker's 505 * exit procedure pointer and the third to a place to store the main 506 * program's object. 507 * 508 * The return value is the main program's entry point. 509 */ 510 func_ptr_type 511 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 512 { 513 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 514 Objlist_Entry *entry; 515 Obj_Entry *last_interposer, *obj, *preload_tail; 516 const Elf_Phdr *phdr; 517 Objlist initlist; 518 RtldLockState lockstate; 519 struct stat st; 520 Elf_Addr *argcp; 521 char **argv, **env, **envp, *kexecpath; 522 const char *argv0, *binpath, *library_path_rpath, *static_tls_extra; 523 struct ld_env_var_desc *lvd; 524 caddr_t imgentry; 525 char buf[MAXPATHLEN]; 526 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 527 size_t sz; 528 #ifdef __powerpc__ 529 int old_auxv_format = 1; 530 #endif 531 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 532 533 /* 534 * On entry, the dynamic linker itself has not been relocated yet. 535 * Be very careful not to reference any global data until after 536 * init_rtld has returned. It is OK to reference file-scope statics 537 * and string constants, and to call static and global functions. 538 */ 539 540 /* Find the auxiliary vector on the stack. */ 541 argcp = sp; 542 argc = *sp++; 543 argv = (char **) sp; 544 sp += argc + 1; /* Skip over arguments and NULL terminator */ 545 env = (char **) sp; 546 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 547 ; 548 aux = (Elf_Auxinfo *) sp; 549 550 /* Digest the auxiliary vector. */ 551 for (i = 0; i < AT_COUNT; i++) 552 aux_info[i] = NULL; 553 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 554 if (auxp->a_type < AT_COUNT) 555 aux_info[auxp->a_type] = auxp; 556 #ifdef __powerpc__ 557 if (auxp->a_type == 23) /* AT_STACKPROT */ 558 old_auxv_format = 0; 559 #endif 560 } 561 562 #ifdef __powerpc__ 563 if (old_auxv_format) { 564 /* Remap from old-style auxv numbers. */ 565 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 566 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 567 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 568 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 569 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 570 aux_info[13] = NULL; /* AT_GID */ 571 572 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 573 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 574 aux_info[16] = aux_info[14]; /* AT_CANARY */ 575 aux_info[14] = NULL; /* AT_EGID */ 576 } 577 #endif 578 579 /* Initialize and relocate ourselves. */ 580 assert(aux_info[AT_BASE] != NULL); 581 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 582 583 dlerror_dflt_init(); 584 585 __progname = obj_rtld.path; 586 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 587 environ = env; 588 main_argc = argc; 589 main_argv = argv; 590 591 if (aux_info[AT_BSDFLAGS] != NULL && 592 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 593 ld_fast_sigblock = true; 594 595 trust = !issetugid(); 596 direct_exec = false; 597 598 md_abi_variant_hook(aux_info); 599 rtld_init_env_vars(env); 600 601 fd = -1; 602 if (aux_info[AT_EXECFD] != NULL) { 603 fd = aux_info[AT_EXECFD]->a_un.a_val; 604 } else { 605 assert(aux_info[AT_PHDR] != NULL); 606 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 607 if (phdr == obj_rtld.phdr) { 608 if (!trust) { 609 _rtld_error("Tainted process refusing to run binary %s", 610 argv0); 611 rtld_die(); 612 } 613 direct_exec = true; 614 615 dbg("opening main program in direct exec mode"); 616 if (argc >= 2) { 617 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 618 &argv0, &dir_ignore); 619 explicit_fd = (fd != -1); 620 binpath = NULL; 621 if (!explicit_fd) 622 fd = open_binary_fd(argv0, search_in_path, &binpath); 623 if (fstat(fd, &st) == -1) { 624 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 625 explicit_fd ? "user-provided descriptor" : argv0, 626 rtld_strerror(errno)); 627 rtld_die(); 628 } 629 630 /* 631 * Rough emulation of the permission checks done by 632 * execve(2), only Unix DACs are checked, ACLs are 633 * ignored. Preserve the semantic of disabling owner 634 * to execute if owner x bit is cleared, even if 635 * others x bit is enabled. 636 * mmap(2) does not allow to mmap with PROT_EXEC if 637 * binary' file comes from noexec mount. We cannot 638 * set a text reference on the binary. 639 */ 640 dir_enable = false; 641 if (st.st_uid == geteuid()) { 642 if ((st.st_mode & S_IXUSR) != 0) 643 dir_enable = true; 644 } else if (st.st_gid == getegid()) { 645 if ((st.st_mode & S_IXGRP) != 0) 646 dir_enable = true; 647 } else if ((st.st_mode & S_IXOTH) != 0) { 648 dir_enable = true; 649 } 650 if (!dir_enable && !dir_ignore) { 651 _rtld_error("No execute permission for binary %s", 652 argv0); 653 rtld_die(); 654 } 655 656 /* 657 * For direct exec mode, argv[0] is the interpreter 658 * name, we must remove it and shift arguments left 659 * before invoking binary main. Since stack layout 660 * places environment pointers and aux vectors right 661 * after the terminating NULL, we must shift 662 * environment and aux as well. 663 */ 664 main_argc = argc - rtld_argc; 665 for (i = 0; i <= main_argc; i++) 666 argv[i] = argv[i + rtld_argc]; 667 *argcp -= rtld_argc; 668 environ = env = envp = argv + main_argc + 1; 669 dbg("move env from %p to %p", envp + rtld_argc, envp); 670 do { 671 *envp = *(envp + rtld_argc); 672 } while (*envp++ != NULL); 673 aux = auxp = (Elf_Auxinfo *)envp; 674 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 675 dbg("move aux from %p to %p", auxpf, aux); 676 /* XXXKIB insert place for AT_EXECPATH if not present */ 677 for (;; auxp++, auxpf++) { 678 *auxp = *auxpf; 679 if (auxp->a_type == AT_NULL) 680 break; 681 } 682 /* Since the auxiliary vector has moved, redigest it. */ 683 for (i = 0; i < AT_COUNT; i++) 684 aux_info[i] = NULL; 685 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 686 if (auxp->a_type < AT_COUNT) 687 aux_info[auxp->a_type] = auxp; 688 } 689 690 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 691 if (binpath == NULL) { 692 aux_info[AT_EXECPATH] = NULL; 693 } else { 694 if (aux_info[AT_EXECPATH] == NULL) { 695 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 696 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 697 } 698 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 699 binpath); 700 } 701 } else { 702 _rtld_error("No binary"); 703 rtld_die(); 704 } 705 } 706 } 707 708 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 709 710 /* 711 * If the process is tainted, then we un-set the dangerous environment 712 * variables. The process will be marked as tainted until setuid(2) 713 * is called. If any child process calls setuid(2) we do not want any 714 * future processes to honor the potentially un-safe variables. 715 */ 716 if (!trust) { 717 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 718 lvd = &ld_env_vars[i]; 719 if (lvd->unsecure) 720 lvd->val = NULL; 721 } 722 } 723 724 ld_debug = ld_get_env_var(LD_DEBUG); 725 if (ld_bind_now == NULL) 726 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 727 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 728 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 729 libmap_override = ld_get_env_var(LD_LIBMAP); 730 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 731 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 732 ld_preload = ld_get_env_var(LD_PRELOAD); 733 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 734 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 735 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 736 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 737 if (library_path_rpath != NULL) { 738 if (library_path_rpath[0] == 'y' || 739 library_path_rpath[0] == 'Y' || 740 library_path_rpath[0] == '1') 741 ld_library_path_rpath = true; 742 else 743 ld_library_path_rpath = false; 744 } 745 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); 746 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { 747 sz = parse_integer(static_tls_extra); 748 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) 749 ld_static_tls_extra = sz; 750 } 751 dangerous_ld_env = libmap_disable || libmap_override != NULL || 752 ld_library_path != NULL || ld_preload != NULL || 753 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || 754 static_tls_extra != NULL; 755 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 756 ld_utrace = ld_get_env_var(LD_UTRACE); 757 758 set_ld_elf_hints_path(); 759 if (ld_debug != NULL && *ld_debug != '\0') 760 debug = 1; 761 dbg("%s is initialized, base address = %p", __progname, 762 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 763 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 764 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 765 766 dbg("initializing thread locks"); 767 lockdflt_init(); 768 769 /* 770 * Load the main program, or process its program header if it is 771 * already loaded. 772 */ 773 if (fd != -1) { /* Load the main program. */ 774 dbg("loading main program"); 775 obj_main = map_object(fd, argv0, NULL); 776 close(fd); 777 if (obj_main == NULL) 778 rtld_die(); 779 max_stack_flags = obj_main->stack_flags; 780 } else { /* Main program already loaded. */ 781 dbg("processing main program's program header"); 782 assert(aux_info[AT_PHDR] != NULL); 783 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 784 assert(aux_info[AT_PHNUM] != NULL); 785 phnum = aux_info[AT_PHNUM]->a_un.a_val; 786 assert(aux_info[AT_PHENT] != NULL); 787 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 788 assert(aux_info[AT_ENTRY] != NULL); 789 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 790 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 791 rtld_die(); 792 } 793 794 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 795 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 796 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 797 if (kexecpath[0] == '/') 798 obj_main->path = kexecpath; 799 else if (getcwd(buf, sizeof(buf)) == NULL || 800 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 801 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 802 obj_main->path = xstrdup(argv0); 803 else 804 obj_main->path = xstrdup(buf); 805 } else { 806 dbg("No AT_EXECPATH or direct exec"); 807 obj_main->path = xstrdup(argv0); 808 } 809 dbg("obj_main path %s", obj_main->path); 810 obj_main->mainprog = true; 811 812 if (aux_info[AT_STACKPROT] != NULL && 813 aux_info[AT_STACKPROT]->a_un.a_val != 0) 814 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 815 816 #ifndef COMPAT_libcompat 817 /* 818 * Get the actual dynamic linker pathname from the executable if 819 * possible. (It should always be possible.) That ensures that 820 * gdb will find the right dynamic linker even if a non-standard 821 * one is being used. 822 */ 823 if (obj_main->interp != NULL && 824 strcmp(obj_main->interp, obj_rtld.path) != 0) { 825 free(obj_rtld.path); 826 obj_rtld.path = xstrdup(obj_main->interp); 827 __progname = obj_rtld.path; 828 } 829 #endif 830 831 if (!digest_dynamic(obj_main, 0)) 832 rtld_die(); 833 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 834 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 835 obj_main->dynsymcount); 836 837 linkmap_add(obj_main); 838 linkmap_add(&obj_rtld); 839 840 /* Link the main program into the list of objects. */ 841 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 842 obj_count++; 843 obj_loads++; 844 845 /* Initialize a fake symbol for resolving undefined weak references. */ 846 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 847 sym_zero.st_shndx = SHN_UNDEF; 848 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 849 850 if (!libmap_disable) 851 libmap_disable = (bool)lm_init(libmap_override); 852 853 if (aux_info[AT_KPRELOAD] != NULL && 854 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 855 dbg("loading kernel vdso"); 856 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 857 rtld_die(); 858 } 859 860 dbg("loading LD_PRELOAD_FDS libraries"); 861 if (load_preload_objects(ld_preload_fds, true) == -1) 862 rtld_die(); 863 864 dbg("loading LD_PRELOAD libraries"); 865 if (load_preload_objects(ld_preload, false) == -1) 866 rtld_die(); 867 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 868 869 dbg("loading needed objects"); 870 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 871 0) == -1) 872 rtld_die(); 873 874 /* Make a list of all objects loaded at startup. */ 875 last_interposer = obj_main; 876 TAILQ_FOREACH(obj, &obj_list, next) { 877 if (obj->marker) 878 continue; 879 if (obj->z_interpose && obj != obj_main) { 880 objlist_put_after(&list_main, last_interposer, obj); 881 last_interposer = obj; 882 } else { 883 objlist_push_tail(&list_main, obj); 884 } 885 obj->refcount++; 886 } 887 888 dbg("checking for required versions"); 889 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 890 rtld_die(); 891 892 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 893 dump_auxv(aux_info); 894 895 if (ld_tracing) { /* We're done */ 896 trace_loaded_objects(obj_main, true); 897 exit(0); 898 } 899 900 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 901 dump_relocations(obj_main); 902 exit (0); 903 } 904 905 /* 906 * Processing tls relocations requires having the tls offsets 907 * initialized. Prepare offsets before starting initial 908 * relocation processing. 909 */ 910 dbg("initializing initial thread local storage offsets"); 911 STAILQ_FOREACH(entry, &list_main, link) { 912 /* 913 * Allocate all the initial objects out of the static TLS 914 * block even if they didn't ask for it. 915 */ 916 allocate_tls_offset(entry->obj); 917 } 918 919 if (relocate_objects(obj_main, 920 ld_bind_now != NULL && *ld_bind_now != '\0', 921 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 922 rtld_die(); 923 924 dbg("doing copy relocations"); 925 if (do_copy_relocations(obj_main) == -1) 926 rtld_die(); 927 928 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 929 dump_relocations(obj_main); 930 exit (0); 931 } 932 933 ifunc_init(aux); 934 935 /* 936 * Setup TLS for main thread. This must be done after the 937 * relocations are processed, since tls initialization section 938 * might be the subject for relocations. 939 */ 940 dbg("initializing initial thread local storage"); 941 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 942 943 dbg("initializing key program variables"); 944 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 945 set_program_var("environ", env); 946 set_program_var("__elf_aux_vector", aux); 947 948 /* Make a list of init functions to call. */ 949 objlist_init(&initlist); 950 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 951 preload_tail, &initlist); 952 953 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 954 955 map_stacks_exec(NULL); 956 957 if (!obj_main->crt_no_init) { 958 /* 959 * Make sure we don't call the main program's init and fini 960 * functions for binaries linked with old crt1 which calls 961 * _init itself. 962 */ 963 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 964 obj_main->preinit_array = obj_main->init_array = 965 obj_main->fini_array = (Elf_Addr)NULL; 966 } 967 968 if (direct_exec) { 969 /* Set osrel for direct-execed binary */ 970 mib[0] = CTL_KERN; 971 mib[1] = KERN_PROC; 972 mib[2] = KERN_PROC_OSREL; 973 mib[3] = getpid(); 974 osrel = obj_main->osrel; 975 sz = sizeof(old_osrel); 976 dbg("setting osrel to %d", osrel); 977 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 978 } 979 980 wlock_acquire(rtld_bind_lock, &lockstate); 981 982 dbg("resolving ifuncs"); 983 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 984 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 985 rtld_die(); 986 987 rtld_exit_ptr = rtld_exit; 988 if (obj_main->crt_no_init) 989 preinit_main(); 990 objlist_call_init(&initlist, &lockstate); 991 _r_debug_postinit(&obj_main->linkmap); 992 objlist_clear(&initlist); 993 dbg("loading filtees"); 994 TAILQ_FOREACH(obj, &obj_list, next) { 995 if (obj->marker) 996 continue; 997 if (ld_loadfltr || obj->z_loadfltr) 998 load_filtees(obj, 0, &lockstate); 999 } 1000 1001 dbg("enforcing main obj relro"); 1002 if (obj_enforce_relro(obj_main) == -1) 1003 rtld_die(); 1004 1005 lock_release(rtld_bind_lock, &lockstate); 1006 1007 dbg("transferring control to program entry point = %p", obj_main->entry); 1008 1009 /* Return the exit procedure and the program entry point. */ 1010 *exit_proc = rtld_exit_ptr; 1011 *objp = obj_main; 1012 return ((func_ptr_type)obj_main->entry); 1013 } 1014 1015 void * 1016 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 1017 { 1018 void *ptr; 1019 Elf_Addr target; 1020 1021 ptr = (void *)make_function_pointer(def, obj); 1022 target = call_ifunc_resolver(ptr); 1023 return ((void *)target); 1024 } 1025 1026 Elf_Addr 1027 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1028 { 1029 const Elf_Rel *rel; 1030 const Elf_Sym *def; 1031 const Obj_Entry *defobj; 1032 Elf_Addr *where; 1033 Elf_Addr target; 1034 RtldLockState lockstate; 1035 1036 rlock_acquire(rtld_bind_lock, &lockstate); 1037 if (sigsetjmp(lockstate.env, 0) != 0) 1038 lock_upgrade(rtld_bind_lock, &lockstate); 1039 if (obj->pltrel) 1040 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1041 else 1042 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1043 1044 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1045 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1046 NULL, &lockstate); 1047 if (def == NULL) 1048 rtld_die(); 1049 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1050 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1051 else 1052 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1053 1054 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1055 defobj->strtab + def->st_name, 1056 obj->path == NULL ? NULL : basename(obj->path), 1057 (void *)target, 1058 defobj->path == NULL ? NULL : basename(defobj->path)); 1059 1060 /* 1061 * Write the new contents for the jmpslot. Note that depending on 1062 * architecture, the value which we need to return back to the 1063 * lazy binding trampoline may or may not be the target 1064 * address. The value returned from reloc_jmpslot() is the value 1065 * that the trampoline needs. 1066 */ 1067 target = reloc_jmpslot(where, target, defobj, obj, rel); 1068 lock_release(rtld_bind_lock, &lockstate); 1069 return (target); 1070 } 1071 1072 /* 1073 * Error reporting function. Use it like printf. If formats the message 1074 * into a buffer, and sets things up so that the next call to dlerror() 1075 * will return the message. 1076 */ 1077 void 1078 _rtld_error(const char *fmt, ...) 1079 { 1080 va_list ap; 1081 1082 va_start(ap, fmt); 1083 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1084 fmt, ap); 1085 va_end(ap); 1086 *lockinfo.dlerror_seen() = 0; 1087 dbg("rtld_error: %s", lockinfo.dlerror_loc()); 1088 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1089 } 1090 1091 /* 1092 * Return a dynamically-allocated copy of the current error message, if any. 1093 */ 1094 static struct dlerror_save * 1095 errmsg_save(void) 1096 { 1097 struct dlerror_save *res; 1098 1099 res = xmalloc(sizeof(*res)); 1100 res->seen = *lockinfo.dlerror_seen(); 1101 if (res->seen == 0) 1102 res->msg = xstrdup(lockinfo.dlerror_loc()); 1103 return (res); 1104 } 1105 1106 /* 1107 * Restore the current error message from a copy which was previously saved 1108 * by errmsg_save(). The copy is freed. 1109 */ 1110 static void 1111 errmsg_restore(struct dlerror_save *saved_msg) 1112 { 1113 if (saved_msg == NULL || saved_msg->seen == 1) { 1114 *lockinfo.dlerror_seen() = 1; 1115 } else { 1116 *lockinfo.dlerror_seen() = 0; 1117 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1118 lockinfo.dlerror_loc_sz); 1119 free(saved_msg->msg); 1120 } 1121 free(saved_msg); 1122 } 1123 1124 static const char * 1125 basename(const char *name) 1126 { 1127 const char *p; 1128 1129 p = strrchr(name, '/'); 1130 return (p != NULL ? p + 1 : name); 1131 } 1132 1133 static struct utsname uts; 1134 1135 static char * 1136 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1137 const char *subst, bool may_free) 1138 { 1139 char *p, *p1, *res, *resp; 1140 int subst_len, kw_len, subst_count, old_len, new_len; 1141 1142 kw_len = strlen(kw); 1143 1144 /* 1145 * First, count the number of the keyword occurrences, to 1146 * preallocate the final string. 1147 */ 1148 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1149 p1 = strstr(p, kw); 1150 if (p1 == NULL) 1151 break; 1152 } 1153 1154 /* 1155 * If the keyword is not found, just return. 1156 * 1157 * Return non-substituted string if resolution failed. We 1158 * cannot do anything more reasonable, the failure mode of the 1159 * caller is unresolved library anyway. 1160 */ 1161 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1162 return (may_free ? real : xstrdup(real)); 1163 if (obj != NULL) 1164 subst = obj->origin_path; 1165 1166 /* 1167 * There is indeed something to substitute. Calculate the 1168 * length of the resulting string, and allocate it. 1169 */ 1170 subst_len = strlen(subst); 1171 old_len = strlen(real); 1172 new_len = old_len + (subst_len - kw_len) * subst_count; 1173 res = xmalloc(new_len + 1); 1174 1175 /* 1176 * Now, execute the substitution loop. 1177 */ 1178 for (p = real, resp = res, *resp = '\0';;) { 1179 p1 = strstr(p, kw); 1180 if (p1 != NULL) { 1181 /* Copy the prefix before keyword. */ 1182 memcpy(resp, p, p1 - p); 1183 resp += p1 - p; 1184 /* Keyword replacement. */ 1185 memcpy(resp, subst, subst_len); 1186 resp += subst_len; 1187 *resp = '\0'; 1188 p = p1 + kw_len; 1189 } else 1190 break; 1191 } 1192 1193 /* Copy to the end of string and finish. */ 1194 strcat(resp, p); 1195 if (may_free) 1196 free(real); 1197 return (res); 1198 } 1199 1200 static const struct { 1201 const char *kw; 1202 bool pass_obj; 1203 const char *subst; 1204 } tokens[] = { 1205 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1206 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1207 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1208 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1209 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1210 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1211 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1212 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1213 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, 1214 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, 1215 }; 1216 1217 static char * 1218 origin_subst(Obj_Entry *obj, const char *real) 1219 { 1220 char *res; 1221 int i; 1222 1223 if (obj == NULL || !trust) 1224 return (xstrdup(real)); 1225 if (uts.sysname[0] == '\0') { 1226 if (uname(&uts) != 0) { 1227 _rtld_error("utsname failed: %d", errno); 1228 return (NULL); 1229 } 1230 } 1231 1232 /* __DECONST is safe here since without may_free real is unchanged */ 1233 res = __DECONST(char *, real); 1234 for (i = 0; i < (int)nitems(tokens); i++) { 1235 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1236 res, tokens[i].kw, tokens[i].subst, i != 0); 1237 } 1238 return (res); 1239 } 1240 1241 void 1242 rtld_die(void) 1243 { 1244 const char *msg = dlerror(); 1245 1246 if (msg == NULL) 1247 msg = "Fatal error"; 1248 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1249 rtld_fdputstr(STDERR_FILENO, msg); 1250 rtld_fdputchar(STDERR_FILENO, '\n'); 1251 _exit(1); 1252 } 1253 1254 /* 1255 * Process a shared object's DYNAMIC section, and save the important 1256 * information in its Obj_Entry structure. 1257 */ 1258 static void 1259 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1260 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1261 { 1262 const Elf_Dyn *dynp; 1263 Needed_Entry **needed_tail = &obj->needed; 1264 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1265 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1266 const Elf_Hashelt *hashtab; 1267 const Elf32_Word *hashval; 1268 Elf32_Word bkt, nmaskwords; 1269 int bloom_size32; 1270 int plttype = DT_REL; 1271 1272 *dyn_rpath = NULL; 1273 *dyn_soname = NULL; 1274 *dyn_runpath = NULL; 1275 1276 obj->bind_now = false; 1277 dynp = obj->dynamic; 1278 if (dynp == NULL) 1279 return; 1280 for (; dynp->d_tag != DT_NULL; dynp++) { 1281 switch (dynp->d_tag) { 1282 1283 case DT_REL: 1284 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1285 break; 1286 1287 case DT_RELSZ: 1288 obj->relsize = dynp->d_un.d_val; 1289 break; 1290 1291 case DT_RELENT: 1292 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1293 break; 1294 1295 case DT_JMPREL: 1296 obj->pltrel = (const Elf_Rel *) 1297 (obj->relocbase + dynp->d_un.d_ptr); 1298 break; 1299 1300 case DT_PLTRELSZ: 1301 obj->pltrelsize = dynp->d_un.d_val; 1302 break; 1303 1304 case DT_RELA: 1305 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1306 break; 1307 1308 case DT_RELASZ: 1309 obj->relasize = dynp->d_un.d_val; 1310 break; 1311 1312 case DT_RELAENT: 1313 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1314 break; 1315 1316 case DT_RELR: 1317 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1318 break; 1319 1320 case DT_RELRSZ: 1321 obj->relrsize = dynp->d_un.d_val; 1322 break; 1323 1324 case DT_RELRENT: 1325 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1326 break; 1327 1328 case DT_PLTREL: 1329 plttype = dynp->d_un.d_val; 1330 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1331 break; 1332 1333 case DT_SYMTAB: 1334 obj->symtab = (const Elf_Sym *) 1335 (obj->relocbase + dynp->d_un.d_ptr); 1336 break; 1337 1338 case DT_SYMENT: 1339 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1340 break; 1341 1342 case DT_STRTAB: 1343 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1344 break; 1345 1346 case DT_STRSZ: 1347 obj->strsize = dynp->d_un.d_val; 1348 break; 1349 1350 case DT_VERNEED: 1351 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1352 dynp->d_un.d_val); 1353 break; 1354 1355 case DT_VERNEEDNUM: 1356 obj->verneednum = dynp->d_un.d_val; 1357 break; 1358 1359 case DT_VERDEF: 1360 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1361 dynp->d_un.d_val); 1362 break; 1363 1364 case DT_VERDEFNUM: 1365 obj->verdefnum = dynp->d_un.d_val; 1366 break; 1367 1368 case DT_VERSYM: 1369 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1370 dynp->d_un.d_val); 1371 break; 1372 1373 case DT_HASH: 1374 { 1375 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1376 dynp->d_un.d_ptr); 1377 obj->nbuckets = hashtab[0]; 1378 obj->nchains = hashtab[1]; 1379 obj->buckets = hashtab + 2; 1380 obj->chains = obj->buckets + obj->nbuckets; 1381 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1382 obj->buckets != NULL; 1383 } 1384 break; 1385 1386 case DT_GNU_HASH: 1387 { 1388 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1389 dynp->d_un.d_ptr); 1390 obj->nbuckets_gnu = hashtab[0]; 1391 obj->symndx_gnu = hashtab[1]; 1392 nmaskwords = hashtab[2]; 1393 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1394 obj->maskwords_bm_gnu = nmaskwords - 1; 1395 obj->shift2_gnu = hashtab[3]; 1396 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1397 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1398 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1399 obj->symndx_gnu; 1400 /* Number of bitmask words is required to be power of 2 */ 1401 obj->valid_hash_gnu = powerof2(nmaskwords) && 1402 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1403 } 1404 break; 1405 1406 case DT_NEEDED: 1407 if (!obj->rtld) { 1408 Needed_Entry *nep = NEW(Needed_Entry); 1409 nep->name = dynp->d_un.d_val; 1410 nep->obj = NULL; 1411 nep->next = NULL; 1412 1413 *needed_tail = nep; 1414 needed_tail = &nep->next; 1415 } 1416 break; 1417 1418 case DT_FILTER: 1419 if (!obj->rtld) { 1420 Needed_Entry *nep = NEW(Needed_Entry); 1421 nep->name = dynp->d_un.d_val; 1422 nep->obj = NULL; 1423 nep->next = NULL; 1424 1425 *needed_filtees_tail = nep; 1426 needed_filtees_tail = &nep->next; 1427 1428 if (obj->linkmap.l_refname == NULL) 1429 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1430 } 1431 break; 1432 1433 case DT_AUXILIARY: 1434 if (!obj->rtld) { 1435 Needed_Entry *nep = NEW(Needed_Entry); 1436 nep->name = dynp->d_un.d_val; 1437 nep->obj = NULL; 1438 nep->next = NULL; 1439 1440 *needed_aux_filtees_tail = nep; 1441 needed_aux_filtees_tail = &nep->next; 1442 } 1443 break; 1444 1445 case DT_PLTGOT: 1446 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1447 break; 1448 1449 case DT_TEXTREL: 1450 obj->textrel = true; 1451 break; 1452 1453 case DT_SYMBOLIC: 1454 obj->symbolic = true; 1455 break; 1456 1457 case DT_RPATH: 1458 /* 1459 * We have to wait until later to process this, because we 1460 * might not have gotten the address of the string table yet. 1461 */ 1462 *dyn_rpath = dynp; 1463 break; 1464 1465 case DT_SONAME: 1466 *dyn_soname = dynp; 1467 break; 1468 1469 case DT_RUNPATH: 1470 *dyn_runpath = dynp; 1471 break; 1472 1473 case DT_INIT: 1474 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1475 break; 1476 1477 case DT_PREINIT_ARRAY: 1478 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1479 break; 1480 1481 case DT_PREINIT_ARRAYSZ: 1482 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1483 break; 1484 1485 case DT_INIT_ARRAY: 1486 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1487 break; 1488 1489 case DT_INIT_ARRAYSZ: 1490 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1491 break; 1492 1493 case DT_FINI: 1494 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1495 break; 1496 1497 case DT_FINI_ARRAY: 1498 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1499 break; 1500 1501 case DT_FINI_ARRAYSZ: 1502 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1503 break; 1504 1505 case DT_DEBUG: 1506 if (!early) 1507 dbg("Filling in DT_DEBUG entry"); 1508 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1509 break; 1510 1511 case DT_FLAGS: 1512 if (dynp->d_un.d_val & DF_ORIGIN) 1513 obj->z_origin = true; 1514 if (dynp->d_un.d_val & DF_SYMBOLIC) 1515 obj->symbolic = true; 1516 if (dynp->d_un.d_val & DF_TEXTREL) 1517 obj->textrel = true; 1518 if (dynp->d_un.d_val & DF_BIND_NOW) 1519 obj->bind_now = true; 1520 if (dynp->d_un.d_val & DF_STATIC_TLS) 1521 obj->static_tls = true; 1522 break; 1523 1524 #ifdef __powerpc__ 1525 #ifdef __powerpc64__ 1526 case DT_PPC64_GLINK: 1527 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1528 break; 1529 #else 1530 case DT_PPC_GOT: 1531 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1532 break; 1533 #endif 1534 #endif 1535 1536 case DT_FLAGS_1: 1537 if (dynp->d_un.d_val & DF_1_NOOPEN) 1538 obj->z_noopen = true; 1539 if (dynp->d_un.d_val & DF_1_ORIGIN) 1540 obj->z_origin = true; 1541 if (dynp->d_un.d_val & DF_1_GLOBAL) 1542 obj->z_global = true; 1543 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1544 obj->bind_now = true; 1545 if (dynp->d_un.d_val & DF_1_NODELETE) 1546 obj->z_nodelete = true; 1547 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1548 obj->z_loadfltr = true; 1549 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1550 obj->z_interpose = true; 1551 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1552 obj->z_nodeflib = true; 1553 if (dynp->d_un.d_val & DF_1_PIE) 1554 obj->z_pie = true; 1555 break; 1556 1557 default: 1558 if (!early) { 1559 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1560 (long)dynp->d_tag); 1561 } 1562 break; 1563 } 1564 } 1565 1566 obj->traced = false; 1567 1568 if (plttype == DT_RELA) { 1569 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1570 obj->pltrel = NULL; 1571 obj->pltrelasize = obj->pltrelsize; 1572 obj->pltrelsize = 0; 1573 } 1574 1575 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1576 if (obj->valid_hash_sysv) 1577 obj->dynsymcount = obj->nchains; 1578 else if (obj->valid_hash_gnu) { 1579 obj->dynsymcount = 0; 1580 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1581 if (obj->buckets_gnu[bkt] == 0) 1582 continue; 1583 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1584 do 1585 obj->dynsymcount++; 1586 while ((*hashval++ & 1u) == 0); 1587 } 1588 obj->dynsymcount += obj->symndx_gnu; 1589 } 1590 1591 if (obj->linkmap.l_refname != NULL) 1592 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1593 linkmap.l_refname; 1594 } 1595 1596 static bool 1597 obj_resolve_origin(Obj_Entry *obj) 1598 { 1599 1600 if (obj->origin_path != NULL) 1601 return (true); 1602 obj->origin_path = xmalloc(PATH_MAX); 1603 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1604 } 1605 1606 static bool 1607 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1608 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1609 { 1610 1611 if (obj->z_origin && !obj_resolve_origin(obj)) 1612 return (false); 1613 1614 if (dyn_runpath != NULL) { 1615 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1616 obj->runpath = origin_subst(obj, obj->runpath); 1617 } else if (dyn_rpath != NULL) { 1618 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1619 obj->rpath = origin_subst(obj, obj->rpath); 1620 } 1621 if (dyn_soname != NULL) 1622 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1623 return (true); 1624 } 1625 1626 static bool 1627 digest_dynamic(Obj_Entry *obj, int early) 1628 { 1629 const Elf_Dyn *dyn_rpath; 1630 const Elf_Dyn *dyn_soname; 1631 const Elf_Dyn *dyn_runpath; 1632 1633 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1634 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1635 } 1636 1637 /* 1638 * Process a shared object's program header. This is used only for the 1639 * main program, when the kernel has already loaded the main program 1640 * into memory before calling the dynamic linker. It creates and 1641 * returns an Obj_Entry structure. 1642 */ 1643 static Obj_Entry * 1644 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1645 { 1646 Obj_Entry *obj; 1647 const Elf_Phdr *phlimit = phdr + phnum; 1648 const Elf_Phdr *ph; 1649 Elf_Addr note_start, note_end; 1650 int nsegs = 0; 1651 1652 obj = obj_new(); 1653 for (ph = phdr; ph < phlimit; ph++) { 1654 if (ph->p_type != PT_PHDR) 1655 continue; 1656 1657 obj->phdr = phdr; 1658 obj->phsize = ph->p_memsz; 1659 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1660 break; 1661 } 1662 1663 obj->stack_flags = PF_X | PF_R | PF_W; 1664 1665 for (ph = phdr; ph < phlimit; ph++) { 1666 switch (ph->p_type) { 1667 1668 case PT_INTERP: 1669 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1670 break; 1671 1672 case PT_LOAD: 1673 if (nsegs == 0) { /* First load segment */ 1674 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); 1675 obj->mapbase = obj->vaddrbase + obj->relocbase; 1676 } else { /* Last load segment */ 1677 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - 1678 obj->vaddrbase; 1679 } 1680 nsegs++; 1681 break; 1682 1683 case PT_DYNAMIC: 1684 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1685 break; 1686 1687 case PT_TLS: 1688 obj->tlsindex = 1; 1689 obj->tlssize = ph->p_memsz; 1690 obj->tlsalign = ph->p_align; 1691 obj->tlsinitsize = ph->p_filesz; 1692 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1693 obj->tlspoffset = ph->p_offset; 1694 break; 1695 1696 case PT_GNU_STACK: 1697 obj->stack_flags = ph->p_flags; 1698 break; 1699 1700 case PT_GNU_RELRO: 1701 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 1702 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) - 1703 rtld_trunc_page(ph->p_vaddr); 1704 break; 1705 1706 case PT_NOTE: 1707 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1708 note_end = note_start + ph->p_filesz; 1709 digest_notes(obj, note_start, note_end); 1710 break; 1711 } 1712 } 1713 if (nsegs < 1) { 1714 _rtld_error("%s: too few PT_LOAD segments", path); 1715 return (NULL); 1716 } 1717 1718 obj->entry = entry; 1719 return (obj); 1720 } 1721 1722 void 1723 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1724 { 1725 const Elf_Note *note; 1726 const char *note_name; 1727 uintptr_t p; 1728 1729 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1730 note = (const Elf_Note *)((const char *)(note + 1) + 1731 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1732 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1733 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1734 note->n_descsz != sizeof(int32_t)) 1735 continue; 1736 if (note->n_type != NT_FREEBSD_ABI_TAG && 1737 note->n_type != NT_FREEBSD_FEATURE_CTL && 1738 note->n_type != NT_FREEBSD_NOINIT_TAG) 1739 continue; 1740 note_name = (const char *)(note + 1); 1741 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1742 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1743 continue; 1744 switch (note->n_type) { 1745 case NT_FREEBSD_ABI_TAG: 1746 /* FreeBSD osrel note */ 1747 p = (uintptr_t)(note + 1); 1748 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1749 obj->osrel = *(const int32_t *)(p); 1750 dbg("note osrel %d", obj->osrel); 1751 break; 1752 case NT_FREEBSD_FEATURE_CTL: 1753 /* FreeBSD ABI feature control note */ 1754 p = (uintptr_t)(note + 1); 1755 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1756 obj->fctl0 = *(const uint32_t *)(p); 1757 dbg("note fctl0 %#x", obj->fctl0); 1758 break; 1759 case NT_FREEBSD_NOINIT_TAG: 1760 /* FreeBSD 'crt does not call init' note */ 1761 obj->crt_no_init = true; 1762 dbg("note crt_no_init"); 1763 break; 1764 } 1765 } 1766 } 1767 1768 static Obj_Entry * 1769 dlcheck(void *handle) 1770 { 1771 Obj_Entry *obj; 1772 1773 TAILQ_FOREACH(obj, &obj_list, next) { 1774 if (obj == (Obj_Entry *) handle) 1775 break; 1776 } 1777 1778 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1779 _rtld_error("Invalid shared object handle %p", handle); 1780 return (NULL); 1781 } 1782 return (obj); 1783 } 1784 1785 /* 1786 * If the given object is already in the donelist, return true. Otherwise 1787 * add the object to the list and return false. 1788 */ 1789 static bool 1790 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1791 { 1792 unsigned int i; 1793 1794 for (i = 0; i < dlp->num_used; i++) 1795 if (dlp->objs[i] == obj) 1796 return (true); 1797 /* 1798 * Our donelist allocation should always be sufficient. But if 1799 * our threads locking isn't working properly, more shared objects 1800 * could have been loaded since we allocated the list. That should 1801 * never happen, but we'll handle it properly just in case it does. 1802 */ 1803 if (dlp->num_used < dlp->num_alloc) 1804 dlp->objs[dlp->num_used++] = obj; 1805 return (false); 1806 } 1807 1808 /* 1809 * SysV hash function for symbol table lookup. It is a slightly optimized 1810 * version of the hash specified by the System V ABI. 1811 */ 1812 Elf32_Word 1813 elf_hash(const char *name) 1814 { 1815 const unsigned char *p = (const unsigned char *)name; 1816 Elf32_Word h = 0; 1817 1818 while (*p != '\0') { 1819 h = (h << 4) + *p++; 1820 h ^= (h >> 24) & 0xf0; 1821 } 1822 return (h & 0x0fffffff); 1823 } 1824 1825 /* 1826 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1827 * unsigned in case it's implemented with a wider type. 1828 */ 1829 static uint32_t 1830 gnu_hash(const char *s) 1831 { 1832 uint32_t h; 1833 unsigned char c; 1834 1835 h = 5381; 1836 for (c = *s; c != '\0'; c = *++s) 1837 h = h * 33 + c; 1838 return (h & 0xffffffff); 1839 } 1840 1841 1842 /* 1843 * Find the library with the given name, and return its full pathname. 1844 * The returned string is dynamically allocated. Generates an error 1845 * message and returns NULL if the library cannot be found. 1846 * 1847 * If the second argument is non-NULL, then it refers to an already- 1848 * loaded shared object, whose library search path will be searched. 1849 * 1850 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1851 * descriptor (which is close-on-exec) will be passed out via the third 1852 * argument. 1853 * 1854 * The search order is: 1855 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1856 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1857 * LD_LIBRARY_PATH 1858 * DT_RUNPATH in the referencing file 1859 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1860 * from list) 1861 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1862 * 1863 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1864 */ 1865 static char * 1866 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1867 { 1868 char *pathname, *refobj_path; 1869 const char *name; 1870 bool nodeflib, objgiven; 1871 1872 objgiven = refobj != NULL; 1873 1874 if (libmap_disable || !objgiven || 1875 (name = lm_find(refobj->path, xname)) == NULL) 1876 name = xname; 1877 1878 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1879 if (name[0] != '/' && !trust) { 1880 _rtld_error("Absolute pathname required " 1881 "for shared object \"%s\"", name); 1882 return (NULL); 1883 } 1884 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1885 __DECONST(char *, name))); 1886 } 1887 1888 dbg(" Searching for \"%s\"", name); 1889 refobj_path = objgiven ? refobj->path : NULL; 1890 1891 /* 1892 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1893 * back to pre-conforming behaviour if user requested so with 1894 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1895 * nodeflib. 1896 */ 1897 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1898 pathname = search_library_path(name, ld_library_path, 1899 refobj_path, fdp); 1900 if (pathname != NULL) 1901 return (pathname); 1902 if (refobj != NULL) { 1903 pathname = search_library_path(name, refobj->rpath, 1904 refobj_path, fdp); 1905 if (pathname != NULL) 1906 return (pathname); 1907 } 1908 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1909 if (pathname != NULL) 1910 return (pathname); 1911 pathname = search_library_path(name, gethints(false), 1912 refobj_path, fdp); 1913 if (pathname != NULL) 1914 return (pathname); 1915 pathname = search_library_path(name, ld_standard_library_path, 1916 refobj_path, fdp); 1917 if (pathname != NULL) 1918 return (pathname); 1919 } else { 1920 nodeflib = objgiven ? refobj->z_nodeflib : false; 1921 if (objgiven) { 1922 pathname = search_library_path(name, refobj->rpath, 1923 refobj->path, fdp); 1924 if (pathname != NULL) 1925 return (pathname); 1926 } 1927 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1928 pathname = search_library_path(name, obj_main->rpath, 1929 refobj_path, fdp); 1930 if (pathname != NULL) 1931 return (pathname); 1932 } 1933 pathname = search_library_path(name, ld_library_path, 1934 refobj_path, fdp); 1935 if (pathname != NULL) 1936 return (pathname); 1937 if (objgiven) { 1938 pathname = search_library_path(name, refobj->runpath, 1939 refobj_path, fdp); 1940 if (pathname != NULL) 1941 return (pathname); 1942 } 1943 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1944 if (pathname != NULL) 1945 return (pathname); 1946 pathname = search_library_path(name, gethints(nodeflib), 1947 refobj_path, fdp); 1948 if (pathname != NULL) 1949 return (pathname); 1950 if (objgiven && !nodeflib) { 1951 pathname = search_library_path(name, 1952 ld_standard_library_path, refobj_path, fdp); 1953 if (pathname != NULL) 1954 return (pathname); 1955 } 1956 } 1957 1958 if (objgiven && refobj->path != NULL) { 1959 _rtld_error("Shared object \"%s\" not found, " 1960 "required by \"%s\"", name, basename(refobj->path)); 1961 } else { 1962 _rtld_error("Shared object \"%s\" not found", name); 1963 } 1964 return (NULL); 1965 } 1966 1967 /* 1968 * Given a symbol number in a referencing object, find the corresponding 1969 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1970 * no definition was found. Returns a pointer to the Obj_Entry of the 1971 * defining object via the reference parameter DEFOBJ_OUT. 1972 */ 1973 const Elf_Sym * 1974 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1975 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1976 RtldLockState *lockstate) 1977 { 1978 const Elf_Sym *ref; 1979 const Elf_Sym *def; 1980 const Obj_Entry *defobj; 1981 const Ver_Entry *ve; 1982 SymLook req; 1983 const char *name; 1984 int res; 1985 1986 /* 1987 * If we have already found this symbol, get the information from 1988 * the cache. 1989 */ 1990 if (symnum >= refobj->dynsymcount) 1991 return (NULL); /* Bad object */ 1992 if (cache != NULL && cache[symnum].sym != NULL) { 1993 *defobj_out = cache[symnum].obj; 1994 return (cache[symnum].sym); 1995 } 1996 1997 ref = refobj->symtab + symnum; 1998 name = refobj->strtab + ref->st_name; 1999 def = NULL; 2000 defobj = NULL; 2001 ve = NULL; 2002 2003 /* 2004 * We don't have to do a full scale lookup if the symbol is local. 2005 * We know it will bind to the instance in this load module; to 2006 * which we already have a pointer (ie ref). By not doing a lookup, 2007 * we not only improve performance, but it also avoids unresolvable 2008 * symbols when local symbols are not in the hash table. This has 2009 * been seen with the ia64 toolchain. 2010 */ 2011 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2012 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2013 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2014 symnum); 2015 } 2016 symlook_init(&req, name); 2017 req.flags = flags; 2018 ve = req.ventry = fetch_ventry(refobj, symnum); 2019 req.lockstate = lockstate; 2020 res = symlook_default(&req, refobj); 2021 if (res == 0) { 2022 def = req.sym_out; 2023 defobj = req.defobj_out; 2024 } 2025 } else { 2026 def = ref; 2027 defobj = refobj; 2028 } 2029 2030 /* 2031 * If we found no definition and the reference is weak, treat the 2032 * symbol as having the value zero. 2033 */ 2034 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2035 def = &sym_zero; 2036 defobj = obj_main; 2037 } 2038 2039 if (def != NULL) { 2040 *defobj_out = defobj; 2041 /* Record the information in the cache to avoid subsequent lookups. */ 2042 if (cache != NULL) { 2043 cache[symnum].sym = def; 2044 cache[symnum].obj = defobj; 2045 } 2046 } else { 2047 if (refobj != &obj_rtld) 2048 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2049 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2050 } 2051 return (def); 2052 } 2053 2054 /* Convert between native byte order and forced little resp. big endian. */ 2055 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) 2056 2057 /* 2058 * Return the search path from the ldconfig hints file, reading it if 2059 * necessary. If nostdlib is true, then the default search paths are 2060 * not added to result. 2061 * 2062 * Returns NULL if there are problems with the hints file, 2063 * or if the search path there is empty. 2064 */ 2065 static const char * 2066 gethints(bool nostdlib) 2067 { 2068 static char *filtered_path; 2069 static const char *hints; 2070 static struct elfhints_hdr hdr; 2071 struct fill_search_info_args sargs, hargs; 2072 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2073 struct dl_serpath *SLPpath, *hintpath; 2074 char *p; 2075 struct stat hint_stat; 2076 unsigned int SLPndx, hintndx, fndx, fcount; 2077 int fd; 2078 size_t flen; 2079 uint32_t dl; 2080 uint32_t magic; /* Magic number */ 2081 uint32_t version; /* File version (1) */ 2082 uint32_t strtab; /* Offset of string table in file */ 2083 uint32_t dirlist; /* Offset of directory list in string table */ 2084 uint32_t dirlistlen; /* strlen(dirlist) */ 2085 bool is_le; /* Does the hints file use little endian */ 2086 bool skip; 2087 2088 /* First call, read the hints file */ 2089 if (hints == NULL) { 2090 /* Keep from trying again in case the hints file is bad. */ 2091 hints = ""; 2092 2093 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { 2094 dbg("failed to open hints file \"%s\"", ld_elf_hints_path); 2095 return (NULL); 2096 } 2097 2098 /* 2099 * Check of hdr.dirlistlen value against type limit 2100 * intends to pacify static analyzers. Further 2101 * paranoia leads to checks that dirlist is fully 2102 * contained in the file range. 2103 */ 2104 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { 2105 dbg("failed to read %lu bytes from hints file \"%s\"", 2106 (u_long)sizeof hdr, ld_elf_hints_path); 2107 cleanup1: 2108 close(fd); 2109 hdr.dirlistlen = 0; 2110 return (NULL); 2111 } 2112 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); 2113 dbg("hints file byte-order: %s-endian", 2114 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big"); 2115 is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC); 2116 magic = COND_SWAP(hdr.magic); 2117 version = COND_SWAP(hdr.version); 2118 strtab = COND_SWAP(hdr.strtab); 2119 dirlist = COND_SWAP(hdr.dirlist); 2120 dirlistlen = COND_SWAP(hdr.dirlistlen); 2121 if (magic != ELFHINTS_MAGIC) { 2122 dbg("invalid magic number %#08x (expected: %#08x)", 2123 magic, ELFHINTS_MAGIC); 2124 goto cleanup1; 2125 } 2126 if (version != 1) { 2127 dbg("hints file version %d (expected: 1)", version); 2128 goto cleanup1; 2129 } 2130 if (dirlistlen > UINT_MAX / 2) { 2131 dbg("directory list is to long: %d > %d", 2132 dirlistlen, UINT_MAX / 2); 2133 goto cleanup1; 2134 } 2135 if (fstat(fd, &hint_stat) == -1) { 2136 dbg("failed to find length of hints file \"%s\"", 2137 ld_elf_hints_path); 2138 goto cleanup1; 2139 } 2140 dl = strtab; 2141 if (dl + dirlist < dl) { 2142 dbg("invalid string table position %d", dl); 2143 goto cleanup1; 2144 } 2145 dl += dirlist; 2146 if (dl + dirlistlen < dl) { 2147 dbg("invalid directory list offset %d", dirlist); 2148 goto cleanup1; 2149 } 2150 dl += dirlistlen; 2151 if (dl > hint_stat.st_size) { 2152 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", 2153 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); 2154 goto cleanup1; 2155 } 2156 p = xmalloc(dirlistlen + 1); 2157 if (pread(fd, p, dirlistlen + 1, 2158 strtab + dirlist) != (ssize_t)dirlistlen + 1 || 2159 p[dirlistlen] != '\0') { 2160 free(p); 2161 dbg("failed to read %d bytes starting at %d from hints file \"%s\"", 2162 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); 2163 goto cleanup1; 2164 } 2165 hints = p; 2166 close(fd); 2167 } 2168 2169 /* 2170 * If caller agreed to receive list which includes the default 2171 * paths, we are done. Otherwise, if we still did not 2172 * calculated filtered result, do it now. 2173 */ 2174 if (!nostdlib) 2175 return (hints[0] != '\0' ? hints : NULL); 2176 if (filtered_path != NULL) 2177 goto filt_ret; 2178 2179 /* 2180 * Obtain the list of all configured search paths, and the 2181 * list of the default paths. 2182 * 2183 * First estimate the size of the results. 2184 */ 2185 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2186 smeta.dls_cnt = 0; 2187 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2188 hmeta.dls_cnt = 0; 2189 2190 sargs.request = RTLD_DI_SERINFOSIZE; 2191 sargs.serinfo = &smeta; 2192 hargs.request = RTLD_DI_SERINFOSIZE; 2193 hargs.serinfo = &hmeta; 2194 2195 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2196 &sargs); 2197 path_enumerate(hints, fill_search_info, NULL, &hargs); 2198 2199 SLPinfo = xmalloc(smeta.dls_size); 2200 hintinfo = xmalloc(hmeta.dls_size); 2201 2202 /* 2203 * Next fetch both sets of paths. 2204 */ 2205 sargs.request = RTLD_DI_SERINFO; 2206 sargs.serinfo = SLPinfo; 2207 sargs.serpath = &SLPinfo->dls_serpath[0]; 2208 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2209 2210 hargs.request = RTLD_DI_SERINFO; 2211 hargs.serinfo = hintinfo; 2212 hargs.serpath = &hintinfo->dls_serpath[0]; 2213 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2214 2215 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2216 &sargs); 2217 path_enumerate(hints, fill_search_info, NULL, &hargs); 2218 2219 /* 2220 * Now calculate the difference between two sets, by excluding 2221 * standard paths from the full set. 2222 */ 2223 fndx = 0; 2224 fcount = 0; 2225 filtered_path = xmalloc(dirlistlen + 1); 2226 hintpath = &hintinfo->dls_serpath[0]; 2227 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2228 skip = false; 2229 SLPpath = &SLPinfo->dls_serpath[0]; 2230 /* 2231 * Check each standard path against current. 2232 */ 2233 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2234 /* matched, skip the path */ 2235 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2236 skip = true; 2237 break; 2238 } 2239 } 2240 if (skip) 2241 continue; 2242 /* 2243 * Not matched against any standard path, add the path 2244 * to result. Separate consequtive paths with ':'. 2245 */ 2246 if (fcount > 0) { 2247 filtered_path[fndx] = ':'; 2248 fndx++; 2249 } 2250 fcount++; 2251 flen = strlen(hintpath->dls_name); 2252 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2253 fndx += flen; 2254 } 2255 filtered_path[fndx] = '\0'; 2256 2257 free(SLPinfo); 2258 free(hintinfo); 2259 2260 filt_ret: 2261 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2262 } 2263 2264 static void 2265 init_dag(Obj_Entry *root) 2266 { 2267 const Needed_Entry *needed; 2268 const Objlist_Entry *elm; 2269 DoneList donelist; 2270 2271 if (root->dag_inited) 2272 return; 2273 donelist_init(&donelist); 2274 2275 /* Root object belongs to own DAG. */ 2276 objlist_push_tail(&root->dldags, root); 2277 objlist_push_tail(&root->dagmembers, root); 2278 donelist_check(&donelist, root); 2279 2280 /* 2281 * Add dependencies of root object to DAG in breadth order 2282 * by exploiting the fact that each new object get added 2283 * to the tail of the dagmembers list. 2284 */ 2285 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2286 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2287 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2288 continue; 2289 objlist_push_tail(&needed->obj->dldags, root); 2290 objlist_push_tail(&root->dagmembers, needed->obj); 2291 } 2292 } 2293 root->dag_inited = true; 2294 } 2295 2296 static void 2297 init_marker(Obj_Entry *marker) 2298 { 2299 2300 bzero(marker, sizeof(*marker)); 2301 marker->marker = true; 2302 } 2303 2304 Obj_Entry * 2305 globallist_curr(const Obj_Entry *obj) 2306 { 2307 2308 for (;;) { 2309 if (obj == NULL) 2310 return (NULL); 2311 if (!obj->marker) 2312 return (__DECONST(Obj_Entry *, obj)); 2313 obj = TAILQ_PREV(obj, obj_entry_q, next); 2314 } 2315 } 2316 2317 Obj_Entry * 2318 globallist_next(const Obj_Entry *obj) 2319 { 2320 2321 for (;;) { 2322 obj = TAILQ_NEXT(obj, next); 2323 if (obj == NULL) 2324 return (NULL); 2325 if (!obj->marker) 2326 return (__DECONST(Obj_Entry *, obj)); 2327 } 2328 } 2329 2330 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2331 static void 2332 hold_object(Obj_Entry *obj) 2333 { 2334 2335 obj->holdcount++; 2336 } 2337 2338 static void 2339 unhold_object(Obj_Entry *obj) 2340 { 2341 2342 assert(obj->holdcount > 0); 2343 if (--obj->holdcount == 0 && obj->unholdfree) 2344 release_object(obj); 2345 } 2346 2347 static void 2348 process_z(Obj_Entry *root) 2349 { 2350 const Objlist_Entry *elm; 2351 Obj_Entry *obj; 2352 2353 /* 2354 * Walk over object DAG and process every dependent object 2355 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2356 * to grow their own DAG. 2357 * 2358 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2359 * symlook_global() to work. 2360 * 2361 * For DF_1_NODELETE, the DAG should have its reference upped. 2362 */ 2363 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2364 obj = elm->obj; 2365 if (obj == NULL) 2366 continue; 2367 if (obj->z_nodelete && !obj->ref_nodel) { 2368 dbg("obj %s -z nodelete", obj->path); 2369 init_dag(obj); 2370 ref_dag(obj); 2371 obj->ref_nodel = true; 2372 } 2373 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2374 dbg("obj %s -z global", obj->path); 2375 objlist_push_tail(&list_global, obj); 2376 init_dag(obj); 2377 } 2378 } 2379 } 2380 2381 static void 2382 parse_rtld_phdr(Obj_Entry *obj) 2383 { 2384 const Elf_Phdr *ph; 2385 Elf_Addr note_start, note_end; 2386 2387 obj->stack_flags = PF_X | PF_R | PF_W; 2388 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2389 obj->phsize; ph++) { 2390 switch (ph->p_type) { 2391 case PT_GNU_STACK: 2392 obj->stack_flags = ph->p_flags; 2393 break; 2394 case PT_GNU_RELRO: 2395 obj->relro_page = obj->relocbase + 2396 rtld_trunc_page(ph->p_vaddr); 2397 obj->relro_size = rtld_round_page(ph->p_memsz); 2398 break; 2399 case PT_NOTE: 2400 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2401 note_end = note_start + ph->p_filesz; 2402 digest_notes(obj, note_start, note_end); 2403 break; 2404 } 2405 } 2406 } 2407 2408 /* 2409 * Initialize the dynamic linker. The argument is the address at which 2410 * the dynamic linker has been mapped into memory. The primary task of 2411 * this function is to relocate the dynamic linker. 2412 */ 2413 static void 2414 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2415 { 2416 Obj_Entry objtmp; /* Temporary rtld object */ 2417 const Elf_Ehdr *ehdr; 2418 const Elf_Dyn *dyn_rpath; 2419 const Elf_Dyn *dyn_soname; 2420 const Elf_Dyn *dyn_runpath; 2421 2422 #ifdef RTLD_INIT_PAGESIZES_EARLY 2423 /* The page size is required by the dynamic memory allocator. */ 2424 init_pagesizes(aux_info); 2425 #endif 2426 2427 /* 2428 * Conjure up an Obj_Entry structure for the dynamic linker. 2429 * 2430 * The "path" member can't be initialized yet because string constants 2431 * cannot yet be accessed. Below we will set it correctly. 2432 */ 2433 memset(&objtmp, 0, sizeof(objtmp)); 2434 objtmp.path = NULL; 2435 objtmp.rtld = true; 2436 objtmp.mapbase = mapbase; 2437 #ifdef PIC 2438 objtmp.relocbase = mapbase; 2439 #endif 2440 2441 objtmp.dynamic = rtld_dynamic(&objtmp); 2442 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2443 assert(objtmp.needed == NULL); 2444 assert(!objtmp.textrel); 2445 /* 2446 * Temporarily put the dynamic linker entry into the object list, so 2447 * that symbols can be found. 2448 */ 2449 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2450 2451 ehdr = (Elf_Ehdr *)mapbase; 2452 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2453 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2454 2455 /* Initialize the object list. */ 2456 TAILQ_INIT(&obj_list); 2457 2458 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2459 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2460 2461 #ifndef RTLD_INIT_PAGESIZES_EARLY 2462 /* The page size is required by the dynamic memory allocator. */ 2463 init_pagesizes(aux_info); 2464 #endif 2465 2466 if (aux_info[AT_OSRELDATE] != NULL) 2467 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2468 2469 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2470 2471 /* Replace the path with a dynamically allocated copy. */ 2472 obj_rtld.path = xstrdup(ld_path_rtld); 2473 2474 parse_rtld_phdr(&obj_rtld); 2475 if (obj_enforce_relro(&obj_rtld) == -1) 2476 rtld_die(); 2477 2478 r_debug.r_version = R_DEBUG_VERSION; 2479 r_debug.r_brk = r_debug_state; 2480 r_debug.r_state = RT_CONSISTENT; 2481 r_debug.r_ldbase = obj_rtld.relocbase; 2482 } 2483 2484 /* 2485 * Retrieve the array of supported page sizes. The kernel provides the page 2486 * sizes in increasing order. 2487 */ 2488 static void 2489 init_pagesizes(Elf_Auxinfo **aux_info) 2490 { 2491 static size_t psa[MAXPAGESIZES]; 2492 int mib[2]; 2493 size_t len, size; 2494 2495 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2496 NULL) { 2497 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2498 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2499 } else { 2500 len = 2; 2501 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2502 size = sizeof(psa); 2503 else { 2504 /* As a fallback, retrieve the base page size. */ 2505 size = sizeof(psa[0]); 2506 if (aux_info[AT_PAGESZ] != NULL) { 2507 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2508 goto psa_filled; 2509 } else { 2510 mib[0] = CTL_HW; 2511 mib[1] = HW_PAGESIZE; 2512 len = 2; 2513 } 2514 } 2515 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2516 _rtld_error("sysctl for hw.pagesize(s) failed"); 2517 rtld_die(); 2518 } 2519 psa_filled: 2520 pagesizes = psa; 2521 } 2522 npagesizes = size / sizeof(pagesizes[0]); 2523 /* Discard any invalid entries at the end of the array. */ 2524 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2525 npagesizes--; 2526 2527 page_size = pagesizes[0]; 2528 } 2529 2530 /* 2531 * Add the init functions from a needed object list (and its recursive 2532 * needed objects) to "list". This is not used directly; it is a helper 2533 * function for initlist_add_objects(). The write lock must be held 2534 * when this function is called. 2535 */ 2536 static void 2537 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2538 { 2539 /* Recursively process the successor needed objects. */ 2540 if (needed->next != NULL) 2541 initlist_add_neededs(needed->next, list); 2542 2543 /* Process the current needed object. */ 2544 if (needed->obj != NULL) 2545 initlist_add_objects(needed->obj, needed->obj, list); 2546 } 2547 2548 /* 2549 * Scan all of the DAGs rooted in the range of objects from "obj" to 2550 * "tail" and add their init functions to "list". This recurses over 2551 * the DAGs and ensure the proper init ordering such that each object's 2552 * needed libraries are initialized before the object itself. At the 2553 * same time, this function adds the objects to the global finalization 2554 * list "list_fini" in the opposite order. The write lock must be 2555 * held when this function is called. 2556 */ 2557 static void 2558 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2559 { 2560 Obj_Entry *nobj; 2561 2562 if (obj->init_scanned || obj->init_done) 2563 return; 2564 obj->init_scanned = true; 2565 2566 /* Recursively process the successor objects. */ 2567 nobj = globallist_next(obj); 2568 if (nobj != NULL && obj != tail) 2569 initlist_add_objects(nobj, tail, list); 2570 2571 /* Recursively process the needed objects. */ 2572 if (obj->needed != NULL) 2573 initlist_add_neededs(obj->needed, list); 2574 if (obj->needed_filtees != NULL) 2575 initlist_add_neededs(obj->needed_filtees, list); 2576 if (obj->needed_aux_filtees != NULL) 2577 initlist_add_neededs(obj->needed_aux_filtees, list); 2578 2579 /* Add the object to the init list. */ 2580 objlist_push_tail(list, obj); 2581 2582 /* Add the object to the global fini list in the reverse order. */ 2583 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2584 && !obj->on_fini_list) { 2585 objlist_push_head(&list_fini, obj); 2586 obj->on_fini_list = true; 2587 } 2588 } 2589 2590 static void 2591 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2592 { 2593 Needed_Entry *needed, *needed1; 2594 2595 for (needed = n; needed != NULL; needed = needed->next) { 2596 if (needed->obj != NULL) { 2597 dlclose_locked(needed->obj, lockstate); 2598 needed->obj = NULL; 2599 } 2600 } 2601 for (needed = n; needed != NULL; needed = needed1) { 2602 needed1 = needed->next; 2603 free(needed); 2604 } 2605 } 2606 2607 static void 2608 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2609 { 2610 2611 free_needed_filtees(obj->needed_filtees, lockstate); 2612 obj->needed_filtees = NULL; 2613 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2614 obj->needed_aux_filtees = NULL; 2615 obj->filtees_loaded = false; 2616 } 2617 2618 static void 2619 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2620 RtldLockState *lockstate) 2621 { 2622 2623 for (; needed != NULL; needed = needed->next) { 2624 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2625 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2626 RTLD_LOCAL, lockstate); 2627 } 2628 } 2629 2630 static void 2631 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2632 { 2633 if (obj->filtees_loaded || obj->filtees_loading) 2634 return; 2635 lock_restart_for_upgrade(lockstate); 2636 obj->filtees_loading = true; 2637 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2638 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2639 obj->filtees_loaded = true; 2640 obj->filtees_loading = false; 2641 } 2642 2643 static int 2644 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2645 { 2646 Obj_Entry *obj1; 2647 2648 for (; needed != NULL; needed = needed->next) { 2649 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2650 flags & ~RTLD_LO_NOLOAD); 2651 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2652 return (-1); 2653 } 2654 return (0); 2655 } 2656 2657 /* 2658 * Given a shared object, traverse its list of needed objects, and load 2659 * each of them. Returns 0 on success. Generates an error message and 2660 * returns -1 on failure. 2661 */ 2662 static int 2663 load_needed_objects(Obj_Entry *first, int flags) 2664 { 2665 Obj_Entry *obj; 2666 2667 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2668 if (obj->marker) 2669 continue; 2670 if (process_needed(obj, obj->needed, flags) == -1) 2671 return (-1); 2672 } 2673 return (0); 2674 } 2675 2676 static int 2677 load_preload_objects(const char *penv, bool isfd) 2678 { 2679 Obj_Entry *obj; 2680 const char *name; 2681 size_t len; 2682 char savech, *p, *psave; 2683 int fd; 2684 static const char delim[] = " \t:;"; 2685 2686 if (penv == NULL) 2687 return (0); 2688 2689 p = psave = xstrdup(penv); 2690 p += strspn(p, delim); 2691 while (*p != '\0') { 2692 len = strcspn(p, delim); 2693 2694 savech = p[len]; 2695 p[len] = '\0'; 2696 if (isfd) { 2697 name = NULL; 2698 fd = parse_integer(p); 2699 if (fd == -1) { 2700 free(psave); 2701 return (-1); 2702 } 2703 } else { 2704 name = p; 2705 fd = -1; 2706 } 2707 2708 obj = load_object(name, fd, NULL, 0); 2709 if (obj == NULL) { 2710 free(psave); 2711 return (-1); /* XXX - cleanup */ 2712 } 2713 obj->z_interpose = true; 2714 p[len] = savech; 2715 p += len; 2716 p += strspn(p, delim); 2717 } 2718 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2719 2720 free(psave); 2721 return (0); 2722 } 2723 2724 static const char * 2725 printable_path(const char *path) 2726 { 2727 2728 return (path == NULL ? "<unknown>" : path); 2729 } 2730 2731 /* 2732 * Load a shared object into memory, if it is not already loaded. The 2733 * object may be specified by name or by user-supplied file descriptor 2734 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2735 * duplicate is. 2736 * 2737 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2738 * on failure. 2739 */ 2740 static Obj_Entry * 2741 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2742 { 2743 Obj_Entry *obj; 2744 int fd; 2745 struct stat sb; 2746 char *path; 2747 2748 fd = -1; 2749 if (name != NULL) { 2750 TAILQ_FOREACH(obj, &obj_list, next) { 2751 if (obj->marker || obj->doomed) 2752 continue; 2753 if (object_match_name(obj, name)) 2754 return (obj); 2755 } 2756 2757 path = find_library(name, refobj, &fd); 2758 if (path == NULL) 2759 return (NULL); 2760 } else 2761 path = NULL; 2762 2763 if (fd >= 0) { 2764 /* 2765 * search_library_pathfds() opens a fresh file descriptor for the 2766 * library, so there is no need to dup(). 2767 */ 2768 } else if (fd_u == -1) { 2769 /* 2770 * If we didn't find a match by pathname, or the name is not 2771 * supplied, open the file and check again by device and inode. 2772 * This avoids false mismatches caused by multiple links or ".." 2773 * in pathnames. 2774 * 2775 * To avoid a race, we open the file and use fstat() rather than 2776 * using stat(). 2777 */ 2778 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2779 _rtld_error("Cannot open \"%s\"", path); 2780 free(path); 2781 return (NULL); 2782 } 2783 } else { 2784 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2785 if (fd == -1) { 2786 _rtld_error("Cannot dup fd"); 2787 free(path); 2788 return (NULL); 2789 } 2790 } 2791 if (fstat(fd, &sb) == -1) { 2792 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2793 close(fd); 2794 free(path); 2795 return (NULL); 2796 } 2797 TAILQ_FOREACH(obj, &obj_list, next) { 2798 if (obj->marker || obj->doomed) 2799 continue; 2800 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2801 break; 2802 } 2803 if (obj != NULL) { 2804 if (name != NULL) 2805 object_add_name(obj, name); 2806 free(path); 2807 close(fd); 2808 return (obj); 2809 } 2810 if (flags & RTLD_LO_NOLOAD) { 2811 free(path); 2812 close(fd); 2813 return (NULL); 2814 } 2815 2816 /* First use of this object, so we must map it in */ 2817 obj = do_load_object(fd, name, path, &sb, flags); 2818 if (obj == NULL) 2819 free(path); 2820 close(fd); 2821 2822 return (obj); 2823 } 2824 2825 static Obj_Entry * 2826 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2827 int flags) 2828 { 2829 Obj_Entry *obj; 2830 struct statfs fs; 2831 2832 /* 2833 * First, make sure that environment variables haven't been 2834 * used to circumvent the noexec flag on a filesystem. 2835 * We ignore fstatfs(2) failures, since fd might reference 2836 * not a file, e.g. shmfd. 2837 */ 2838 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2839 (fs.f_flags & MNT_NOEXEC) != 0) { 2840 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2841 return (NULL); 2842 } 2843 2844 dbg("loading \"%s\"", printable_path(path)); 2845 obj = map_object(fd, printable_path(path), sbp); 2846 if (obj == NULL) 2847 return (NULL); 2848 2849 /* 2850 * If DT_SONAME is present in the object, digest_dynamic2 already 2851 * added it to the object names. 2852 */ 2853 if (name != NULL) 2854 object_add_name(obj, name); 2855 obj->path = path; 2856 if (!digest_dynamic(obj, 0)) 2857 goto errp; 2858 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2859 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2860 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2861 dbg("refusing to load PIE executable \"%s\"", obj->path); 2862 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2863 goto errp; 2864 } 2865 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2866 RTLD_LO_DLOPEN) { 2867 dbg("refusing to load non-loadable \"%s\"", obj->path); 2868 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2869 goto errp; 2870 } 2871 2872 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2873 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2874 obj_count++; 2875 obj_loads++; 2876 linkmap_add(obj); /* for GDB & dlinfo() */ 2877 max_stack_flags |= obj->stack_flags; 2878 2879 dbg(" %p .. %p: %s", obj->mapbase, 2880 obj->mapbase + obj->mapsize - 1, obj->path); 2881 if (obj->textrel) 2882 dbg(" WARNING: %s has impure text", obj->path); 2883 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2884 obj->path); 2885 2886 return (obj); 2887 2888 errp: 2889 munmap(obj->mapbase, obj->mapsize); 2890 obj_free(obj); 2891 return (NULL); 2892 } 2893 2894 static int 2895 load_kpreload(const void *addr) 2896 { 2897 Obj_Entry *obj; 2898 const Elf_Ehdr *ehdr; 2899 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2900 static const char kname[] = "[vdso]"; 2901 2902 ehdr = addr; 2903 if (!check_elf_headers(ehdr, "kpreload")) 2904 return (-1); 2905 obj = obj_new(); 2906 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2907 obj->phdr = phdr; 2908 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2909 phlimit = phdr + ehdr->e_phnum; 2910 seg0 = segn = NULL; 2911 2912 for (; phdr < phlimit; phdr++) { 2913 switch (phdr->p_type) { 2914 case PT_DYNAMIC: 2915 phdyn = phdr; 2916 break; 2917 case PT_GNU_STACK: 2918 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2919 obj->stack_flags = phdr->p_flags; 2920 break; 2921 case PT_LOAD: 2922 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2923 seg0 = phdr; 2924 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2925 phdr->p_vaddr + phdr->p_memsz) 2926 segn = phdr; 2927 break; 2928 } 2929 } 2930 2931 obj->mapbase = __DECONST(caddr_t, addr); 2932 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2933 obj->vaddrbase = 0; 2934 obj->relocbase = obj->mapbase; 2935 2936 object_add_name(obj, kname); 2937 obj->path = xstrdup(kname); 2938 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2939 2940 if (!digest_dynamic(obj, 0)) { 2941 obj_free(obj); 2942 return (-1); 2943 } 2944 2945 /* 2946 * We assume that kernel-preloaded object does not need 2947 * relocation. It is currently written into read-only page, 2948 * handling relocations would mean we need to allocate at 2949 * least one additional page per AS. 2950 */ 2951 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2952 obj->path, obj->mapbase, obj->phdr, seg0, 2953 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2954 2955 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2956 obj_count++; 2957 obj_loads++; 2958 linkmap_add(obj); /* for GDB & dlinfo() */ 2959 max_stack_flags |= obj->stack_flags; 2960 2961 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2962 return (0); 2963 } 2964 2965 Obj_Entry * 2966 obj_from_addr(const void *addr) 2967 { 2968 Obj_Entry *obj; 2969 2970 TAILQ_FOREACH(obj, &obj_list, next) { 2971 if (obj->marker) 2972 continue; 2973 if (addr < (void *) obj->mapbase) 2974 continue; 2975 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2976 return obj; 2977 } 2978 return (NULL); 2979 } 2980 2981 static void 2982 preinit_main(void) 2983 { 2984 Elf_Addr *preinit_addr; 2985 int index; 2986 2987 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2988 if (preinit_addr == NULL) 2989 return; 2990 2991 for (index = 0; index < obj_main->preinit_array_num; index++) { 2992 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2993 dbg("calling preinit function for %s at %p", obj_main->path, 2994 (void *)preinit_addr[index]); 2995 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2996 0, 0, obj_main->path); 2997 call_init_pointer(obj_main, preinit_addr[index]); 2998 } 2999 } 3000 } 3001 3002 /* 3003 * Call the finalization functions for each of the objects in "list" 3004 * belonging to the DAG of "root" and referenced once. If NULL "root" 3005 * is specified, every finalization function will be called regardless 3006 * of the reference count and the list elements won't be freed. All of 3007 * the objects are expected to have non-NULL fini functions. 3008 */ 3009 static void 3010 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 3011 { 3012 Objlist_Entry *elm; 3013 struct dlerror_save *saved_msg; 3014 Elf_Addr *fini_addr; 3015 int index; 3016 3017 assert(root == NULL || root->refcount == 1); 3018 3019 if (root != NULL) 3020 root->doomed = true; 3021 3022 /* 3023 * Preserve the current error message since a fini function might 3024 * call into the dynamic linker and overwrite it. 3025 */ 3026 saved_msg = errmsg_save(); 3027 do { 3028 STAILQ_FOREACH(elm, list, link) { 3029 if (root != NULL && (elm->obj->refcount != 1 || 3030 objlist_find(&root->dagmembers, elm->obj) == NULL)) 3031 continue; 3032 /* Remove object from fini list to prevent recursive invocation. */ 3033 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3034 /* Ensure that new references cannot be acquired. */ 3035 elm->obj->doomed = true; 3036 3037 hold_object(elm->obj); 3038 lock_release(rtld_bind_lock, lockstate); 3039 /* 3040 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3041 * When this happens, DT_FINI_ARRAY is processed first. 3042 */ 3043 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3044 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3045 for (index = elm->obj->fini_array_num - 1; index >= 0; 3046 index--) { 3047 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3048 dbg("calling fini function for %s at %p", 3049 elm->obj->path, (void *)fini_addr[index]); 3050 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3051 (void *)fini_addr[index], 0, 0, elm->obj->path); 3052 call_initfini_pointer(elm->obj, fini_addr[index]); 3053 } 3054 } 3055 } 3056 if (elm->obj->fini != (Elf_Addr)NULL) { 3057 dbg("calling fini function for %s at %p", elm->obj->path, 3058 (void *)elm->obj->fini); 3059 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3060 0, 0, elm->obj->path); 3061 call_initfini_pointer(elm->obj, elm->obj->fini); 3062 } 3063 wlock_acquire(rtld_bind_lock, lockstate); 3064 unhold_object(elm->obj); 3065 /* No need to free anything if process is going down. */ 3066 if (root != NULL) 3067 free(elm); 3068 /* 3069 * We must restart the list traversal after every fini call 3070 * because a dlclose() call from the fini function or from 3071 * another thread might have modified the reference counts. 3072 */ 3073 break; 3074 } 3075 } while (elm != NULL); 3076 errmsg_restore(saved_msg); 3077 } 3078 3079 /* 3080 * Call the initialization functions for each of the objects in 3081 * "list". All of the objects are expected to have non-NULL init 3082 * functions. 3083 */ 3084 static void 3085 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3086 { 3087 Objlist_Entry *elm; 3088 Obj_Entry *obj; 3089 struct dlerror_save *saved_msg; 3090 Elf_Addr *init_addr; 3091 void (*reg)(void (*)(void)); 3092 int index; 3093 3094 /* 3095 * Clean init_scanned flag so that objects can be rechecked and 3096 * possibly initialized earlier if any of vectors called below 3097 * cause the change by using dlopen. 3098 */ 3099 TAILQ_FOREACH(obj, &obj_list, next) { 3100 if (obj->marker) 3101 continue; 3102 obj->init_scanned = false; 3103 } 3104 3105 /* 3106 * Preserve the current error message since an init function might 3107 * call into the dynamic linker and overwrite it. 3108 */ 3109 saved_msg = errmsg_save(); 3110 STAILQ_FOREACH(elm, list, link) { 3111 if (elm->obj->init_done) /* Initialized early. */ 3112 continue; 3113 /* 3114 * Race: other thread might try to use this object before current 3115 * one completes the initialization. Not much can be done here 3116 * without better locking. 3117 */ 3118 elm->obj->init_done = true; 3119 hold_object(elm->obj); 3120 reg = NULL; 3121 if (elm->obj == obj_main && obj_main->crt_no_init) { 3122 reg = (void (*)(void (*)(void)))get_program_var_addr( 3123 "__libc_atexit", lockstate); 3124 } 3125 lock_release(rtld_bind_lock, lockstate); 3126 if (reg != NULL) { 3127 reg(rtld_exit); 3128 rtld_exit_ptr = rtld_nop_exit; 3129 } 3130 3131 /* 3132 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3133 * When this happens, DT_INIT is processed first. 3134 */ 3135 if (elm->obj->init != (Elf_Addr)NULL) { 3136 dbg("calling init function for %s at %p", elm->obj->path, 3137 (void *)elm->obj->init); 3138 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3139 0, 0, elm->obj->path); 3140 call_init_pointer(elm->obj, elm->obj->init); 3141 } 3142 init_addr = (Elf_Addr *)elm->obj->init_array; 3143 if (init_addr != NULL) { 3144 for (index = 0; index < elm->obj->init_array_num; index++) { 3145 if (init_addr[index] != 0 && init_addr[index] != 1) { 3146 dbg("calling init function for %s at %p", elm->obj->path, 3147 (void *)init_addr[index]); 3148 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3149 (void *)init_addr[index], 0, 0, elm->obj->path); 3150 call_init_pointer(elm->obj, init_addr[index]); 3151 } 3152 } 3153 } 3154 wlock_acquire(rtld_bind_lock, lockstate); 3155 unhold_object(elm->obj); 3156 } 3157 errmsg_restore(saved_msg); 3158 } 3159 3160 static void 3161 objlist_clear(Objlist *list) 3162 { 3163 Objlist_Entry *elm; 3164 3165 while (!STAILQ_EMPTY(list)) { 3166 elm = STAILQ_FIRST(list); 3167 STAILQ_REMOVE_HEAD(list, link); 3168 free(elm); 3169 } 3170 } 3171 3172 static Objlist_Entry * 3173 objlist_find(Objlist *list, const Obj_Entry *obj) 3174 { 3175 Objlist_Entry *elm; 3176 3177 STAILQ_FOREACH(elm, list, link) 3178 if (elm->obj == obj) 3179 return elm; 3180 return (NULL); 3181 } 3182 3183 static void 3184 objlist_init(Objlist *list) 3185 { 3186 STAILQ_INIT(list); 3187 } 3188 3189 static void 3190 objlist_push_head(Objlist *list, Obj_Entry *obj) 3191 { 3192 Objlist_Entry *elm; 3193 3194 elm = NEW(Objlist_Entry); 3195 elm->obj = obj; 3196 STAILQ_INSERT_HEAD(list, elm, link); 3197 } 3198 3199 static void 3200 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3201 { 3202 Objlist_Entry *elm; 3203 3204 elm = NEW(Objlist_Entry); 3205 elm->obj = obj; 3206 STAILQ_INSERT_TAIL(list, elm, link); 3207 } 3208 3209 static void 3210 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3211 { 3212 Objlist_Entry *elm, *listelm; 3213 3214 STAILQ_FOREACH(listelm, list, link) { 3215 if (listelm->obj == listobj) 3216 break; 3217 } 3218 elm = NEW(Objlist_Entry); 3219 elm->obj = obj; 3220 if (listelm != NULL) 3221 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3222 else 3223 STAILQ_INSERT_TAIL(list, elm, link); 3224 } 3225 3226 static void 3227 objlist_remove(Objlist *list, Obj_Entry *obj) 3228 { 3229 Objlist_Entry *elm; 3230 3231 if ((elm = objlist_find(list, obj)) != NULL) { 3232 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3233 free(elm); 3234 } 3235 } 3236 3237 /* 3238 * Relocate dag rooted in the specified object. 3239 * Returns 0 on success, or -1 on failure. 3240 */ 3241 3242 static int 3243 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3244 int flags, RtldLockState *lockstate) 3245 { 3246 Objlist_Entry *elm; 3247 int error; 3248 3249 error = 0; 3250 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3251 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3252 lockstate); 3253 if (error == -1) 3254 break; 3255 } 3256 return (error); 3257 } 3258 3259 /* 3260 * Prepare for, or clean after, relocating an object marked with 3261 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3262 * segments are remapped read-write. After relocations are done, the 3263 * segment's permissions are returned back to the modes specified in 3264 * the phdrs. If any relocation happened, or always for wired 3265 * program, COW is triggered. 3266 */ 3267 static int 3268 reloc_textrel_prot(Obj_Entry *obj, bool before) 3269 { 3270 const Elf_Phdr *ph; 3271 void *base; 3272 size_t l, sz; 3273 int prot; 3274 3275 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3276 l--, ph++) { 3277 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3278 continue; 3279 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3280 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3281 rtld_trunc_page(ph->p_vaddr); 3282 prot = before ? (PROT_READ | PROT_WRITE) : 3283 convert_prot(ph->p_flags); 3284 if (mprotect(base, sz, prot) == -1) { 3285 _rtld_error("%s: Cannot write-%sable text segment: %s", 3286 obj->path, before ? "en" : "dis", 3287 rtld_strerror(errno)); 3288 return (-1); 3289 } 3290 } 3291 return (0); 3292 } 3293 3294 /* Process RELR relative relocations. */ 3295 static void 3296 reloc_relr(Obj_Entry *obj) 3297 { 3298 const Elf_Relr *relr, *relrlim; 3299 Elf_Addr *where; 3300 3301 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3302 for (relr = obj->relr; relr < relrlim; relr++) { 3303 Elf_Relr entry = *relr; 3304 3305 if ((entry & 1) == 0) { 3306 where = (Elf_Addr *)(obj->relocbase + entry); 3307 *where++ += (Elf_Addr)obj->relocbase; 3308 } else { 3309 for (long i = 0; (entry >>= 1) != 0; i++) 3310 if ((entry & 1) != 0) 3311 where[i] += (Elf_Addr)obj->relocbase; 3312 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3313 } 3314 } 3315 } 3316 3317 /* 3318 * Relocate single object. 3319 * Returns 0 on success, or -1 on failure. 3320 */ 3321 static int 3322 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3323 int flags, RtldLockState *lockstate) 3324 { 3325 3326 if (obj->relocated) 3327 return (0); 3328 obj->relocated = true; 3329 if (obj != rtldobj) 3330 dbg("relocating \"%s\"", obj->path); 3331 3332 if (obj->symtab == NULL || obj->strtab == NULL || 3333 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3334 dbg("object %s has no run-time symbol table", obj->path); 3335 3336 /* There are relocations to the write-protected text segment. */ 3337 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3338 return (-1); 3339 3340 /* Process the non-PLT non-IFUNC relocations. */ 3341 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3342 return (-1); 3343 reloc_relr(obj); 3344 3345 /* Re-protected the text segment. */ 3346 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3347 return (-1); 3348 3349 /* Set the special PLT or GOT entries. */ 3350 init_pltgot(obj); 3351 3352 /* Process the PLT relocations. */ 3353 if (reloc_plt(obj, flags, lockstate) == -1) 3354 return (-1); 3355 /* Relocate the jump slots if we are doing immediate binding. */ 3356 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3357 lockstate) == -1) 3358 return (-1); 3359 3360 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3361 return (-1); 3362 3363 /* 3364 * Set up the magic number and version in the Obj_Entry. These 3365 * were checked in the crt1.o from the original ElfKit, so we 3366 * set them for backward compatibility. 3367 */ 3368 obj->magic = RTLD_MAGIC; 3369 obj->version = RTLD_VERSION; 3370 3371 return (0); 3372 } 3373 3374 /* 3375 * Relocate newly-loaded shared objects. The argument is a pointer to 3376 * the Obj_Entry for the first such object. All objects from the first 3377 * to the end of the list of objects are relocated. Returns 0 on success, 3378 * or -1 on failure. 3379 */ 3380 static int 3381 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3382 int flags, RtldLockState *lockstate) 3383 { 3384 Obj_Entry *obj; 3385 int error; 3386 3387 for (error = 0, obj = first; obj != NULL; 3388 obj = TAILQ_NEXT(obj, next)) { 3389 if (obj->marker) 3390 continue; 3391 error = relocate_object(obj, bind_now, rtldobj, flags, 3392 lockstate); 3393 if (error == -1) 3394 break; 3395 } 3396 return (error); 3397 } 3398 3399 /* 3400 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3401 * referencing STT_GNU_IFUNC symbols is postponed till the other 3402 * relocations are done. The indirect functions specified as 3403 * ifunc are allowed to call other symbols, so we need to have 3404 * objects relocated before asking for resolution from indirects. 3405 * 3406 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3407 * instead of the usual lazy handling of PLT slots. It is 3408 * consistent with how GNU does it. 3409 */ 3410 static int 3411 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3412 RtldLockState *lockstate) 3413 { 3414 3415 if (obj->ifuncs_resolved) 3416 return (0); 3417 obj->ifuncs_resolved = true; 3418 if (!obj->irelative && !obj->irelative_nonplt && 3419 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3420 !obj->non_plt_gnu_ifunc) 3421 return (0); 3422 if (obj_disable_relro(obj) == -1 || 3423 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3424 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3425 lockstate) == -1) || 3426 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3427 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3428 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3429 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3430 obj_enforce_relro(obj) == -1) 3431 return (-1); 3432 return (0); 3433 } 3434 3435 static int 3436 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3437 RtldLockState *lockstate) 3438 { 3439 Objlist_Entry *elm; 3440 Obj_Entry *obj; 3441 3442 STAILQ_FOREACH(elm, list, link) { 3443 obj = elm->obj; 3444 if (obj->marker) 3445 continue; 3446 if (resolve_object_ifunc(obj, bind_now, flags, 3447 lockstate) == -1) 3448 return (-1); 3449 } 3450 return (0); 3451 } 3452 3453 /* 3454 * Cleanup procedure. It will be called (by the atexit mechanism) just 3455 * before the process exits. 3456 */ 3457 static void 3458 rtld_exit(void) 3459 { 3460 RtldLockState lockstate; 3461 3462 wlock_acquire(rtld_bind_lock, &lockstate); 3463 dbg("rtld_exit()"); 3464 objlist_call_fini(&list_fini, NULL, &lockstate); 3465 /* No need to remove the items from the list, since we are exiting. */ 3466 if (!libmap_disable) 3467 lm_fini(); 3468 lock_release(rtld_bind_lock, &lockstate); 3469 } 3470 3471 static void 3472 rtld_nop_exit(void) 3473 { 3474 } 3475 3476 /* 3477 * Iterate over a search path, translate each element, and invoke the 3478 * callback on the result. 3479 */ 3480 static void * 3481 path_enumerate(const char *path, path_enum_proc callback, 3482 const char *refobj_path, void *arg) 3483 { 3484 const char *trans; 3485 if (path == NULL) 3486 return (NULL); 3487 3488 path += strspn(path, ":;"); 3489 while (*path != '\0') { 3490 size_t len; 3491 char *res; 3492 3493 len = strcspn(path, ":;"); 3494 trans = lm_findn(refobj_path, path, len); 3495 if (trans) 3496 res = callback(trans, strlen(trans), arg); 3497 else 3498 res = callback(path, len, arg); 3499 3500 if (res != NULL) 3501 return (res); 3502 3503 path += len; 3504 path += strspn(path, ":;"); 3505 } 3506 3507 return (NULL); 3508 } 3509 3510 struct try_library_args { 3511 const char *name; 3512 size_t namelen; 3513 char *buffer; 3514 size_t buflen; 3515 int fd; 3516 }; 3517 3518 static void * 3519 try_library_path(const char *dir, size_t dirlen, void *param) 3520 { 3521 struct try_library_args *arg; 3522 int fd; 3523 3524 arg = param; 3525 if (*dir == '/' || trust) { 3526 char *pathname; 3527 3528 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3529 return (NULL); 3530 3531 pathname = arg->buffer; 3532 strncpy(pathname, dir, dirlen); 3533 pathname[dirlen] = '/'; 3534 strcpy(pathname + dirlen + 1, arg->name); 3535 3536 dbg(" Trying \"%s\"", pathname); 3537 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3538 if (fd >= 0) { 3539 dbg(" Opened \"%s\", fd %d", pathname, fd); 3540 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3541 strcpy(pathname, arg->buffer); 3542 arg->fd = fd; 3543 return (pathname); 3544 } else { 3545 dbg(" Failed to open \"%s\": %s", 3546 pathname, rtld_strerror(errno)); 3547 } 3548 } 3549 return (NULL); 3550 } 3551 3552 static char * 3553 search_library_path(const char *name, const char *path, 3554 const char *refobj_path, int *fdp) 3555 { 3556 char *p; 3557 struct try_library_args arg; 3558 3559 if (path == NULL) 3560 return (NULL); 3561 3562 arg.name = name; 3563 arg.namelen = strlen(name); 3564 arg.buffer = xmalloc(PATH_MAX); 3565 arg.buflen = PATH_MAX; 3566 arg.fd = -1; 3567 3568 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3569 *fdp = arg.fd; 3570 3571 free(arg.buffer); 3572 3573 return (p); 3574 } 3575 3576 3577 /* 3578 * Finds the library with the given name using the directory descriptors 3579 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3580 * 3581 * Returns a freshly-opened close-on-exec file descriptor for the library, 3582 * or -1 if the library cannot be found. 3583 */ 3584 static char * 3585 search_library_pathfds(const char *name, const char *path, int *fdp) 3586 { 3587 char *envcopy, *fdstr, *found, *last_token; 3588 size_t len; 3589 int dirfd, fd; 3590 3591 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3592 3593 /* Don't load from user-specified libdirs into setuid binaries. */ 3594 if (!trust) 3595 return (NULL); 3596 3597 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3598 if (path == NULL) 3599 return (NULL); 3600 3601 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3602 if (name[0] == '/') { 3603 dbg("Absolute path (%s) passed to %s", name, __func__); 3604 return (NULL); 3605 } 3606 3607 /* 3608 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3609 * copy of the path, as strtok_r rewrites separator tokens 3610 * with '\0'. 3611 */ 3612 found = NULL; 3613 envcopy = xstrdup(path); 3614 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3615 fdstr = strtok_r(NULL, ":", &last_token)) { 3616 dirfd = parse_integer(fdstr); 3617 if (dirfd < 0) { 3618 _rtld_error("failed to parse directory FD: '%s'", 3619 fdstr); 3620 break; 3621 } 3622 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3623 if (fd >= 0) { 3624 *fdp = fd; 3625 len = strlen(fdstr) + strlen(name) + 3; 3626 found = xmalloc(len); 3627 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3628 _rtld_error("error generating '%d/%s'", 3629 dirfd, name); 3630 rtld_die(); 3631 } 3632 dbg("open('%s') => %d", found, fd); 3633 break; 3634 } 3635 } 3636 free(envcopy); 3637 3638 return (found); 3639 } 3640 3641 3642 int 3643 dlclose(void *handle) 3644 { 3645 RtldLockState lockstate; 3646 int error; 3647 3648 wlock_acquire(rtld_bind_lock, &lockstate); 3649 error = dlclose_locked(handle, &lockstate); 3650 lock_release(rtld_bind_lock, &lockstate); 3651 return (error); 3652 } 3653 3654 static int 3655 dlclose_locked(void *handle, RtldLockState *lockstate) 3656 { 3657 Obj_Entry *root; 3658 3659 root = dlcheck(handle); 3660 if (root == NULL) 3661 return (-1); 3662 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3663 root->path); 3664 3665 /* Unreference the object and its dependencies. */ 3666 root->dl_refcount--; 3667 3668 if (root->refcount == 1) { 3669 /* 3670 * The object will be no longer referenced, so we must unload it. 3671 * First, call the fini functions. 3672 */ 3673 objlist_call_fini(&list_fini, root, lockstate); 3674 3675 unref_dag(root); 3676 3677 /* Finish cleaning up the newly-unreferenced objects. */ 3678 GDB_STATE(RT_DELETE,&root->linkmap); 3679 unload_object(root, lockstate); 3680 GDB_STATE(RT_CONSISTENT,NULL); 3681 } else 3682 unref_dag(root); 3683 3684 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3685 return (0); 3686 } 3687 3688 char * 3689 dlerror(void) 3690 { 3691 if (*(lockinfo.dlerror_seen()) != 0) 3692 return (NULL); 3693 *lockinfo.dlerror_seen() = 1; 3694 return (lockinfo.dlerror_loc()); 3695 } 3696 3697 /* 3698 * This function is deprecated and has no effect. 3699 */ 3700 void 3701 dllockinit(void *context, 3702 void *(*_lock_create)(void *context) __unused, 3703 void (*_rlock_acquire)(void *lock) __unused, 3704 void (*_wlock_acquire)(void *lock) __unused, 3705 void (*_lock_release)(void *lock) __unused, 3706 void (*_lock_destroy)(void *lock) __unused, 3707 void (*context_destroy)(void *context)) 3708 { 3709 static void *cur_context; 3710 static void (*cur_context_destroy)(void *); 3711 3712 /* Just destroy the context from the previous call, if necessary. */ 3713 if (cur_context_destroy != NULL) 3714 cur_context_destroy(cur_context); 3715 cur_context = context; 3716 cur_context_destroy = context_destroy; 3717 } 3718 3719 void * 3720 dlopen(const char *name, int mode) 3721 { 3722 3723 return (rtld_dlopen(name, -1, mode)); 3724 } 3725 3726 void * 3727 fdlopen(int fd, int mode) 3728 { 3729 3730 return (rtld_dlopen(NULL, fd, mode)); 3731 } 3732 3733 static void * 3734 rtld_dlopen(const char *name, int fd, int mode) 3735 { 3736 RtldLockState lockstate; 3737 int lo_flags; 3738 3739 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3740 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3741 if (ld_tracing != NULL) { 3742 rlock_acquire(rtld_bind_lock, &lockstate); 3743 if (sigsetjmp(lockstate.env, 0) != 0) 3744 lock_upgrade(rtld_bind_lock, &lockstate); 3745 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3746 lock_release(rtld_bind_lock, &lockstate); 3747 } 3748 lo_flags = RTLD_LO_DLOPEN; 3749 if (mode & RTLD_NODELETE) 3750 lo_flags |= RTLD_LO_NODELETE; 3751 if (mode & RTLD_NOLOAD) 3752 lo_flags |= RTLD_LO_NOLOAD; 3753 if (mode & RTLD_DEEPBIND) 3754 lo_flags |= RTLD_LO_DEEPBIND; 3755 if (ld_tracing != NULL) 3756 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3757 3758 return (dlopen_object(name, fd, obj_main, lo_flags, 3759 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3760 } 3761 3762 static void 3763 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3764 { 3765 3766 obj->dl_refcount--; 3767 unref_dag(obj); 3768 if (obj->refcount == 0) 3769 unload_object(obj, lockstate); 3770 } 3771 3772 static Obj_Entry * 3773 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3774 int mode, RtldLockState *lockstate) 3775 { 3776 Obj_Entry *obj; 3777 Objlist initlist; 3778 RtldLockState mlockstate; 3779 int result; 3780 3781 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3782 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3783 refobj->path, lo_flags, mode); 3784 objlist_init(&initlist); 3785 3786 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3787 wlock_acquire(rtld_bind_lock, &mlockstate); 3788 lockstate = &mlockstate; 3789 } 3790 GDB_STATE(RT_ADD,NULL); 3791 3792 obj = NULL; 3793 if (name == NULL && fd == -1) { 3794 obj = obj_main; 3795 obj->refcount++; 3796 } else { 3797 obj = load_object(name, fd, refobj, lo_flags); 3798 } 3799 3800 if (obj) { 3801 obj->dl_refcount++; 3802 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3803 objlist_push_tail(&list_global, obj); 3804 3805 if (!obj->init_done) { 3806 /* We loaded something new and have to init something. */ 3807 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3808 obj->deepbind = true; 3809 result = 0; 3810 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3811 obj->static_tls && !allocate_tls_offset(obj)) { 3812 _rtld_error("%s: No space available " 3813 "for static Thread Local Storage", obj->path); 3814 result = -1; 3815 } 3816 if (result != -1) 3817 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3818 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3819 init_dag(obj); 3820 ref_dag(obj); 3821 if (result != -1) 3822 result = rtld_verify_versions(&obj->dagmembers); 3823 if (result != -1 && ld_tracing) 3824 goto trace; 3825 if (result == -1 || relocate_object_dag(obj, 3826 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3827 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3828 lockstate) == -1) { 3829 dlopen_cleanup(obj, lockstate); 3830 obj = NULL; 3831 } else if (lo_flags & RTLD_LO_EARLY) { 3832 /* 3833 * Do not call the init functions for early loaded 3834 * filtees. The image is still not initialized enough 3835 * for them to work. 3836 * 3837 * Our object is found by the global object list and 3838 * will be ordered among all init calls done right 3839 * before transferring control to main. 3840 */ 3841 } else { 3842 /* Make list of init functions to call. */ 3843 initlist_add_objects(obj, obj, &initlist); 3844 } 3845 /* 3846 * Process all no_delete or global objects here, given 3847 * them own DAGs to prevent their dependencies from being 3848 * unloaded. This has to be done after we have loaded all 3849 * of the dependencies, so that we do not miss any. 3850 */ 3851 if (obj != NULL) 3852 process_z(obj); 3853 } else { 3854 /* 3855 * Bump the reference counts for objects on this DAG. If 3856 * this is the first dlopen() call for the object that was 3857 * already loaded as a dependency, initialize the dag 3858 * starting at it. 3859 */ 3860 init_dag(obj); 3861 ref_dag(obj); 3862 3863 if ((lo_flags & RTLD_LO_TRACE) != 0) 3864 goto trace; 3865 } 3866 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3867 obj->z_nodelete) && !obj->ref_nodel) { 3868 dbg("obj %s nodelete", obj->path); 3869 ref_dag(obj); 3870 obj->z_nodelete = obj->ref_nodel = true; 3871 } 3872 } 3873 3874 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3875 name); 3876 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3877 3878 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3879 map_stacks_exec(lockstate); 3880 if (obj != NULL) 3881 distribute_static_tls(&initlist, lockstate); 3882 } 3883 3884 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3885 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3886 lockstate) == -1) { 3887 objlist_clear(&initlist); 3888 dlopen_cleanup(obj, lockstate); 3889 if (lockstate == &mlockstate) 3890 lock_release(rtld_bind_lock, lockstate); 3891 return (NULL); 3892 } 3893 3894 if (!(lo_flags & RTLD_LO_EARLY)) { 3895 /* Call the init functions. */ 3896 objlist_call_init(&initlist, lockstate); 3897 } 3898 objlist_clear(&initlist); 3899 if (lockstate == &mlockstate) 3900 lock_release(rtld_bind_lock, lockstate); 3901 return (obj); 3902 trace: 3903 trace_loaded_objects(obj, false); 3904 if (lockstate == &mlockstate) 3905 lock_release(rtld_bind_lock, lockstate); 3906 exit(0); 3907 } 3908 3909 static void * 3910 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3911 int flags) 3912 { 3913 DoneList donelist; 3914 const Obj_Entry *obj, *defobj; 3915 const Elf_Sym *def; 3916 SymLook req; 3917 RtldLockState lockstate; 3918 tls_index ti; 3919 void *sym; 3920 int res; 3921 3922 def = NULL; 3923 defobj = NULL; 3924 symlook_init(&req, name); 3925 req.ventry = ve; 3926 req.flags = flags | SYMLOOK_IN_PLT; 3927 req.lockstate = &lockstate; 3928 3929 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3930 rlock_acquire(rtld_bind_lock, &lockstate); 3931 if (sigsetjmp(lockstate.env, 0) != 0) 3932 lock_upgrade(rtld_bind_lock, &lockstate); 3933 if (handle == NULL || handle == RTLD_NEXT || 3934 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3935 3936 if ((obj = obj_from_addr(retaddr)) == NULL) { 3937 _rtld_error("Cannot determine caller's shared object"); 3938 lock_release(rtld_bind_lock, &lockstate); 3939 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3940 return (NULL); 3941 } 3942 if (handle == NULL) { /* Just the caller's shared object. */ 3943 res = symlook_obj(&req, obj); 3944 if (res == 0) { 3945 def = req.sym_out; 3946 defobj = req.defobj_out; 3947 } 3948 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3949 handle == RTLD_SELF) { /* ... caller included */ 3950 if (handle == RTLD_NEXT) 3951 obj = globallist_next(obj); 3952 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3953 if (obj->marker) 3954 continue; 3955 res = symlook_obj(&req, obj); 3956 if (res == 0) { 3957 if (def == NULL || (ld_dynamic_weak && 3958 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3959 def = req.sym_out; 3960 defobj = req.defobj_out; 3961 if (!ld_dynamic_weak || 3962 ELF_ST_BIND(def->st_info) != STB_WEAK) 3963 break; 3964 } 3965 } 3966 } 3967 /* 3968 * Search the dynamic linker itself, and possibly resolve the 3969 * symbol from there. This is how the application links to 3970 * dynamic linker services such as dlopen. 3971 * Note that we ignore ld_dynamic_weak == false case, 3972 * always overriding weak symbols by rtld definitions. 3973 */ 3974 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3975 res = symlook_obj(&req, &obj_rtld); 3976 if (res == 0) { 3977 def = req.sym_out; 3978 defobj = req.defobj_out; 3979 } 3980 } 3981 } else { 3982 assert(handle == RTLD_DEFAULT); 3983 res = symlook_default(&req, obj); 3984 if (res == 0) { 3985 defobj = req.defobj_out; 3986 def = req.sym_out; 3987 } 3988 } 3989 } else { 3990 if ((obj = dlcheck(handle)) == NULL) { 3991 lock_release(rtld_bind_lock, &lockstate); 3992 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3993 return (NULL); 3994 } 3995 3996 donelist_init(&donelist); 3997 if (obj->mainprog) { 3998 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3999 res = symlook_global(&req, &donelist); 4000 if (res == 0) { 4001 def = req.sym_out; 4002 defobj = req.defobj_out; 4003 } 4004 /* 4005 * Search the dynamic linker itself, and possibly resolve the 4006 * symbol from there. This is how the application links to 4007 * dynamic linker services such as dlopen. 4008 */ 4009 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 4010 res = symlook_obj(&req, &obj_rtld); 4011 if (res == 0) { 4012 def = req.sym_out; 4013 defobj = req.defobj_out; 4014 } 4015 } 4016 } 4017 else { 4018 /* Search the whole DAG rooted at the given object. */ 4019 res = symlook_list(&req, &obj->dagmembers, &donelist); 4020 if (res == 0) { 4021 def = req.sym_out; 4022 defobj = req.defobj_out; 4023 } 4024 } 4025 } 4026 4027 if (def != NULL) { 4028 lock_release(rtld_bind_lock, &lockstate); 4029 4030 /* 4031 * The value required by the caller is derived from the value 4032 * of the symbol. this is simply the relocated value of the 4033 * symbol. 4034 */ 4035 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 4036 sym = make_function_pointer(def, defobj); 4037 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 4038 sym = rtld_resolve_ifunc(defobj, def); 4039 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4040 ti.ti_module = defobj->tlsindex; 4041 ti.ti_offset = def->st_value; 4042 sym = __tls_get_addr(&ti); 4043 } else 4044 sym = defobj->relocbase + def->st_value; 4045 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4046 return (sym); 4047 } 4048 4049 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4050 ve != NULL ? ve->name : ""); 4051 lock_release(rtld_bind_lock, &lockstate); 4052 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4053 return (NULL); 4054 } 4055 4056 void * 4057 dlsym(void *handle, const char *name) 4058 { 4059 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4060 SYMLOOK_DLSYM)); 4061 } 4062 4063 dlfunc_t 4064 dlfunc(void *handle, const char *name) 4065 { 4066 union { 4067 void *d; 4068 dlfunc_t f; 4069 } rv; 4070 4071 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4072 SYMLOOK_DLSYM); 4073 return (rv.f); 4074 } 4075 4076 void * 4077 dlvsym(void *handle, const char *name, const char *version) 4078 { 4079 Ver_Entry ventry; 4080 4081 ventry.name = version; 4082 ventry.file = NULL; 4083 ventry.hash = elf_hash(version); 4084 ventry.flags= 0; 4085 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4086 SYMLOOK_DLSYM)); 4087 } 4088 4089 int 4090 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4091 { 4092 const Obj_Entry *obj; 4093 RtldLockState lockstate; 4094 4095 rlock_acquire(rtld_bind_lock, &lockstate); 4096 obj = obj_from_addr(addr); 4097 if (obj == NULL) { 4098 _rtld_error("No shared object contains address"); 4099 lock_release(rtld_bind_lock, &lockstate); 4100 return (0); 4101 } 4102 rtld_fill_dl_phdr_info(obj, phdr_info); 4103 lock_release(rtld_bind_lock, &lockstate); 4104 return (1); 4105 } 4106 4107 int 4108 dladdr(const void *addr, Dl_info *info) 4109 { 4110 const Obj_Entry *obj; 4111 const Elf_Sym *def; 4112 void *symbol_addr; 4113 unsigned long symoffset; 4114 RtldLockState lockstate; 4115 4116 rlock_acquire(rtld_bind_lock, &lockstate); 4117 obj = obj_from_addr(addr); 4118 if (obj == NULL) { 4119 _rtld_error("No shared object contains address"); 4120 lock_release(rtld_bind_lock, &lockstate); 4121 return (0); 4122 } 4123 info->dli_fname = obj->path; 4124 info->dli_fbase = obj->mapbase; 4125 info->dli_saddr = (void *)0; 4126 info->dli_sname = NULL; 4127 4128 /* 4129 * Walk the symbol list looking for the symbol whose address is 4130 * closest to the address sent in. 4131 */ 4132 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4133 def = obj->symtab + symoffset; 4134 4135 /* 4136 * For skip the symbol if st_shndx is either SHN_UNDEF or 4137 * SHN_COMMON. 4138 */ 4139 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4140 continue; 4141 4142 /* 4143 * If the symbol is greater than the specified address, or if it 4144 * is further away from addr than the current nearest symbol, 4145 * then reject it. 4146 */ 4147 symbol_addr = obj->relocbase + def->st_value; 4148 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4149 continue; 4150 4151 /* Update our idea of the nearest symbol. */ 4152 info->dli_sname = obj->strtab + def->st_name; 4153 info->dli_saddr = symbol_addr; 4154 4155 /* Exact match? */ 4156 if (info->dli_saddr == addr) 4157 break; 4158 } 4159 lock_release(rtld_bind_lock, &lockstate); 4160 return (1); 4161 } 4162 4163 int 4164 dlinfo(void *handle, int request, void *p) 4165 { 4166 const Obj_Entry *obj; 4167 RtldLockState lockstate; 4168 int error; 4169 4170 rlock_acquire(rtld_bind_lock, &lockstate); 4171 4172 if (handle == NULL || handle == RTLD_SELF) { 4173 void *retaddr; 4174 4175 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4176 if ((obj = obj_from_addr(retaddr)) == NULL) 4177 _rtld_error("Cannot determine caller's shared object"); 4178 } else 4179 obj = dlcheck(handle); 4180 4181 if (obj == NULL) { 4182 lock_release(rtld_bind_lock, &lockstate); 4183 return (-1); 4184 } 4185 4186 error = 0; 4187 switch (request) { 4188 case RTLD_DI_LINKMAP: 4189 *((struct link_map const **)p) = &obj->linkmap; 4190 break; 4191 case RTLD_DI_ORIGIN: 4192 error = rtld_dirname(obj->path, p); 4193 break; 4194 4195 case RTLD_DI_SERINFOSIZE: 4196 case RTLD_DI_SERINFO: 4197 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4198 break; 4199 4200 default: 4201 _rtld_error("Invalid request %d passed to dlinfo()", request); 4202 error = -1; 4203 } 4204 4205 lock_release(rtld_bind_lock, &lockstate); 4206 4207 return (error); 4208 } 4209 4210 static void 4211 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4212 { 4213 uintptr_t **dtvp; 4214 4215 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4216 phdr_info->dlpi_name = obj->path; 4217 phdr_info->dlpi_phdr = obj->phdr; 4218 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4219 phdr_info->dlpi_tls_modid = obj->tlsindex; 4220 dtvp = &_tcb_get()->tcb_dtv; 4221 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4222 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4223 phdr_info->dlpi_adds = obj_loads; 4224 phdr_info->dlpi_subs = obj_loads - obj_count; 4225 } 4226 4227 int 4228 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4229 { 4230 struct dl_phdr_info phdr_info; 4231 Obj_Entry *obj, marker; 4232 RtldLockState bind_lockstate, phdr_lockstate; 4233 int error; 4234 4235 init_marker(&marker); 4236 error = 0; 4237 4238 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4239 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4240 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4241 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4242 rtld_fill_dl_phdr_info(obj, &phdr_info); 4243 hold_object(obj); 4244 lock_release(rtld_bind_lock, &bind_lockstate); 4245 4246 error = callback(&phdr_info, sizeof phdr_info, param); 4247 4248 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4249 unhold_object(obj); 4250 obj = globallist_next(&marker); 4251 TAILQ_REMOVE(&obj_list, &marker, next); 4252 if (error != 0) { 4253 lock_release(rtld_bind_lock, &bind_lockstate); 4254 lock_release(rtld_phdr_lock, &phdr_lockstate); 4255 return (error); 4256 } 4257 } 4258 4259 if (error == 0) { 4260 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4261 lock_release(rtld_bind_lock, &bind_lockstate); 4262 error = callback(&phdr_info, sizeof(phdr_info), param); 4263 } 4264 lock_release(rtld_phdr_lock, &phdr_lockstate); 4265 return (error); 4266 } 4267 4268 static void * 4269 fill_search_info(const char *dir, size_t dirlen, void *param) 4270 { 4271 struct fill_search_info_args *arg; 4272 4273 arg = param; 4274 4275 if (arg->request == RTLD_DI_SERINFOSIZE) { 4276 arg->serinfo->dls_cnt ++; 4277 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4278 } else { 4279 struct dl_serpath *s_entry; 4280 4281 s_entry = arg->serpath; 4282 s_entry->dls_name = arg->strspace; 4283 s_entry->dls_flags = arg->flags; 4284 4285 strncpy(arg->strspace, dir, dirlen); 4286 arg->strspace[dirlen] = '\0'; 4287 4288 arg->strspace += dirlen + 1; 4289 arg->serpath++; 4290 } 4291 4292 return (NULL); 4293 } 4294 4295 static int 4296 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4297 { 4298 struct dl_serinfo _info; 4299 struct fill_search_info_args args; 4300 4301 args.request = RTLD_DI_SERINFOSIZE; 4302 args.serinfo = &_info; 4303 4304 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4305 _info.dls_cnt = 0; 4306 4307 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4308 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4309 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4310 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4311 if (!obj->z_nodeflib) 4312 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4313 4314 4315 if (request == RTLD_DI_SERINFOSIZE) { 4316 info->dls_size = _info.dls_size; 4317 info->dls_cnt = _info.dls_cnt; 4318 return (0); 4319 } 4320 4321 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4322 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4323 return (-1); 4324 } 4325 4326 args.request = RTLD_DI_SERINFO; 4327 args.serinfo = info; 4328 args.serpath = &info->dls_serpath[0]; 4329 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4330 4331 args.flags = LA_SER_RUNPATH; 4332 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4333 return (-1); 4334 4335 args.flags = LA_SER_LIBPATH; 4336 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4337 return (-1); 4338 4339 args.flags = LA_SER_RUNPATH; 4340 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4341 return (-1); 4342 4343 args.flags = LA_SER_CONFIG; 4344 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4345 != NULL) 4346 return (-1); 4347 4348 args.flags = LA_SER_DEFAULT; 4349 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4350 fill_search_info, NULL, &args) != NULL) 4351 return (-1); 4352 return (0); 4353 } 4354 4355 static int 4356 rtld_dirname(const char *path, char *bname) 4357 { 4358 const char *endp; 4359 4360 /* Empty or NULL string gets treated as "." */ 4361 if (path == NULL || *path == '\0') { 4362 bname[0] = '.'; 4363 bname[1] = '\0'; 4364 return (0); 4365 } 4366 4367 /* Strip trailing slashes */ 4368 endp = path + strlen(path) - 1; 4369 while (endp > path && *endp == '/') 4370 endp--; 4371 4372 /* Find the start of the dir */ 4373 while (endp > path && *endp != '/') 4374 endp--; 4375 4376 /* Either the dir is "/" or there are no slashes */ 4377 if (endp == path) { 4378 bname[0] = *endp == '/' ? '/' : '.'; 4379 bname[1] = '\0'; 4380 return (0); 4381 } else { 4382 do { 4383 endp--; 4384 } while (endp > path && *endp == '/'); 4385 } 4386 4387 if (endp - path + 2 > PATH_MAX) 4388 { 4389 _rtld_error("Filename is too long: %s", path); 4390 return(-1); 4391 } 4392 4393 strncpy(bname, path, endp - path + 1); 4394 bname[endp - path + 1] = '\0'; 4395 return (0); 4396 } 4397 4398 static int 4399 rtld_dirname_abs(const char *path, char *base) 4400 { 4401 char *last; 4402 4403 if (realpath(path, base) == NULL) { 4404 _rtld_error("realpath \"%s\" failed (%s)", path, 4405 rtld_strerror(errno)); 4406 return (-1); 4407 } 4408 dbg("%s -> %s", path, base); 4409 last = strrchr(base, '/'); 4410 if (last == NULL) { 4411 _rtld_error("non-abs result from realpath \"%s\"", path); 4412 return (-1); 4413 } 4414 if (last != base) 4415 *last = '\0'; 4416 return (0); 4417 } 4418 4419 static void 4420 linkmap_add(Obj_Entry *obj) 4421 { 4422 struct link_map *l, *prev; 4423 4424 l = &obj->linkmap; 4425 l->l_name = obj->path; 4426 l->l_base = obj->mapbase; 4427 l->l_ld = obj->dynamic; 4428 l->l_addr = obj->relocbase; 4429 4430 if (r_debug.r_map == NULL) { 4431 r_debug.r_map = l; 4432 return; 4433 } 4434 4435 /* 4436 * Scan to the end of the list, but not past the entry for the 4437 * dynamic linker, which we want to keep at the very end. 4438 */ 4439 for (prev = r_debug.r_map; 4440 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4441 prev = prev->l_next) 4442 ; 4443 4444 /* Link in the new entry. */ 4445 l->l_prev = prev; 4446 l->l_next = prev->l_next; 4447 if (l->l_next != NULL) 4448 l->l_next->l_prev = l; 4449 prev->l_next = l; 4450 } 4451 4452 static void 4453 linkmap_delete(Obj_Entry *obj) 4454 { 4455 struct link_map *l; 4456 4457 l = &obj->linkmap; 4458 if (l->l_prev == NULL) { 4459 if ((r_debug.r_map = l->l_next) != NULL) 4460 l->l_next->l_prev = NULL; 4461 return; 4462 } 4463 4464 if ((l->l_prev->l_next = l->l_next) != NULL) 4465 l->l_next->l_prev = l->l_prev; 4466 } 4467 4468 /* 4469 * Function for the debugger to set a breakpoint on to gain control. 4470 * 4471 * The two parameters allow the debugger to easily find and determine 4472 * what the runtime loader is doing and to whom it is doing it. 4473 * 4474 * When the loadhook trap is hit (r_debug_state, set at program 4475 * initialization), the arguments can be found on the stack: 4476 * 4477 * +8 struct link_map *m 4478 * +4 struct r_debug *rd 4479 * +0 RetAddr 4480 */ 4481 void 4482 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4483 { 4484 /* 4485 * The following is a hack to force the compiler to emit calls to 4486 * this function, even when optimizing. If the function is empty, 4487 * the compiler is not obliged to emit any code for calls to it, 4488 * even when marked __noinline. However, gdb depends on those 4489 * calls being made. 4490 */ 4491 __compiler_membar(); 4492 } 4493 4494 /* 4495 * A function called after init routines have completed. This can be used to 4496 * break before a program's entry routine is called, and can be used when 4497 * main is not available in the symbol table. 4498 */ 4499 void 4500 _r_debug_postinit(struct link_map *m __unused) 4501 { 4502 4503 /* See r_debug_state(). */ 4504 __compiler_membar(); 4505 } 4506 4507 static void 4508 release_object(Obj_Entry *obj) 4509 { 4510 4511 if (obj->holdcount > 0) { 4512 obj->unholdfree = true; 4513 return; 4514 } 4515 munmap(obj->mapbase, obj->mapsize); 4516 linkmap_delete(obj); 4517 obj_free(obj); 4518 } 4519 4520 /* 4521 * Get address of the pointer variable in the main program. 4522 * Prefer non-weak symbol over the weak one. 4523 */ 4524 static const void ** 4525 get_program_var_addr(const char *name, RtldLockState *lockstate) 4526 { 4527 SymLook req; 4528 DoneList donelist; 4529 4530 symlook_init(&req, name); 4531 req.lockstate = lockstate; 4532 donelist_init(&donelist); 4533 if (symlook_global(&req, &donelist) != 0) 4534 return (NULL); 4535 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4536 return ((const void **)make_function_pointer(req.sym_out, 4537 req.defobj_out)); 4538 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4539 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4540 else 4541 return ((const void **)(req.defobj_out->relocbase + 4542 req.sym_out->st_value)); 4543 } 4544 4545 /* 4546 * Set a pointer variable in the main program to the given value. This 4547 * is used to set key variables such as "environ" before any of the 4548 * init functions are called. 4549 */ 4550 static void 4551 set_program_var(const char *name, const void *value) 4552 { 4553 const void **addr; 4554 4555 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4556 dbg("\"%s\": *%p <-- %p", name, addr, value); 4557 *addr = value; 4558 } 4559 } 4560 4561 /* 4562 * Search the global objects, including dependencies and main object, 4563 * for the given symbol. 4564 */ 4565 static int 4566 symlook_global(SymLook *req, DoneList *donelist) 4567 { 4568 SymLook req1; 4569 const Objlist_Entry *elm; 4570 int res; 4571 4572 symlook_init_from_req(&req1, req); 4573 4574 /* Search all objects loaded at program start up. */ 4575 if (req->defobj_out == NULL || (ld_dynamic_weak && 4576 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4577 res = symlook_list(&req1, &list_main, donelist); 4578 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4579 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4580 req->sym_out = req1.sym_out; 4581 req->defobj_out = req1.defobj_out; 4582 assert(req->defobj_out != NULL); 4583 } 4584 } 4585 4586 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4587 STAILQ_FOREACH(elm, &list_global, link) { 4588 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4589 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4590 break; 4591 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4592 if (res == 0 && (req->defobj_out == NULL || 4593 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4594 req->sym_out = req1.sym_out; 4595 req->defobj_out = req1.defobj_out; 4596 assert(req->defobj_out != NULL); 4597 } 4598 } 4599 4600 return (req->sym_out != NULL ? 0 : ESRCH); 4601 } 4602 4603 /* 4604 * Given a symbol name in a referencing object, find the corresponding 4605 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4606 * no definition was found. Returns a pointer to the Obj_Entry of the 4607 * defining object via the reference parameter DEFOBJ_OUT. 4608 */ 4609 static int 4610 symlook_default(SymLook *req, const Obj_Entry *refobj) 4611 { 4612 DoneList donelist; 4613 const Objlist_Entry *elm; 4614 SymLook req1; 4615 int res; 4616 4617 donelist_init(&donelist); 4618 symlook_init_from_req(&req1, req); 4619 4620 /* 4621 * Look first in the referencing object if linked symbolically, 4622 * and similarly handle protected symbols. 4623 */ 4624 res = symlook_obj(&req1, refobj); 4625 if (res == 0 && (refobj->symbolic || 4626 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4627 req->sym_out = req1.sym_out; 4628 req->defobj_out = req1.defobj_out; 4629 assert(req->defobj_out != NULL); 4630 } 4631 if (refobj->symbolic || req->defobj_out != NULL) 4632 donelist_check(&donelist, refobj); 4633 4634 if (!refobj->deepbind) 4635 symlook_global(req, &donelist); 4636 4637 /* Search all dlopened DAGs containing the referencing object. */ 4638 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4639 if (req->sym_out != NULL && (!ld_dynamic_weak || 4640 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4641 break; 4642 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4643 if (res == 0 && (req->sym_out == NULL || 4644 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4645 req->sym_out = req1.sym_out; 4646 req->defobj_out = req1.defobj_out; 4647 assert(req->defobj_out != NULL); 4648 } 4649 } 4650 4651 if (refobj->deepbind) 4652 symlook_global(req, &donelist); 4653 4654 /* 4655 * Search the dynamic linker itself, and possibly resolve the 4656 * symbol from there. This is how the application links to 4657 * dynamic linker services such as dlopen. 4658 */ 4659 if (req->sym_out == NULL || 4660 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4661 res = symlook_obj(&req1, &obj_rtld); 4662 if (res == 0) { 4663 req->sym_out = req1.sym_out; 4664 req->defobj_out = req1.defobj_out; 4665 assert(req->defobj_out != NULL); 4666 } 4667 } 4668 4669 return (req->sym_out != NULL ? 0 : ESRCH); 4670 } 4671 4672 static int 4673 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4674 { 4675 const Elf_Sym *def; 4676 const Obj_Entry *defobj; 4677 const Objlist_Entry *elm; 4678 SymLook req1; 4679 int res; 4680 4681 def = NULL; 4682 defobj = NULL; 4683 STAILQ_FOREACH(elm, objlist, link) { 4684 if (donelist_check(dlp, elm->obj)) 4685 continue; 4686 symlook_init_from_req(&req1, req); 4687 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4688 if (def == NULL || (ld_dynamic_weak && 4689 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4690 def = req1.sym_out; 4691 defobj = req1.defobj_out; 4692 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4693 break; 4694 } 4695 } 4696 } 4697 if (def != NULL) { 4698 req->sym_out = def; 4699 req->defobj_out = defobj; 4700 return (0); 4701 } 4702 return (ESRCH); 4703 } 4704 4705 /* 4706 * Search the chain of DAGS cointed to by the given Needed_Entry 4707 * for a symbol of the given name. Each DAG is scanned completely 4708 * before advancing to the next one. Returns a pointer to the symbol, 4709 * or NULL if no definition was found. 4710 */ 4711 static int 4712 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4713 { 4714 const Elf_Sym *def; 4715 const Needed_Entry *n; 4716 const Obj_Entry *defobj; 4717 SymLook req1; 4718 int res; 4719 4720 def = NULL; 4721 defobj = NULL; 4722 symlook_init_from_req(&req1, req); 4723 for (n = needed; n != NULL; n = n->next) { 4724 if (n->obj == NULL || 4725 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4726 continue; 4727 if (def == NULL || (ld_dynamic_weak && 4728 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4729 def = req1.sym_out; 4730 defobj = req1.defobj_out; 4731 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4732 break; 4733 } 4734 } 4735 if (def != NULL) { 4736 req->sym_out = def; 4737 req->defobj_out = defobj; 4738 return (0); 4739 } 4740 return (ESRCH); 4741 } 4742 4743 static int 4744 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, 4745 Needed_Entry *needed) 4746 { 4747 DoneList donelist; 4748 int flags; 4749 4750 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; 4751 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4752 donelist_init(&donelist); 4753 symlook_init_from_req(req1, req); 4754 return (symlook_needed(req1, needed, &donelist)); 4755 } 4756 4757 /* 4758 * Search the symbol table of a single shared object for a symbol of 4759 * the given name and version, if requested. Returns a pointer to the 4760 * symbol, or NULL if no definition was found. If the object is 4761 * filter, return filtered symbol from filtee. 4762 * 4763 * The symbol's hash value is passed in for efficiency reasons; that 4764 * eliminates many recomputations of the hash value. 4765 */ 4766 int 4767 symlook_obj(SymLook *req, const Obj_Entry *obj) 4768 { 4769 SymLook req1; 4770 int res, mres; 4771 4772 /* 4773 * If there is at least one valid hash at this point, we prefer to 4774 * use the faster GNU version if available. 4775 */ 4776 if (obj->valid_hash_gnu) 4777 mres = symlook_obj1_gnu(req, obj); 4778 else if (obj->valid_hash_sysv) 4779 mres = symlook_obj1_sysv(req, obj); 4780 else 4781 return (EINVAL); 4782 4783 if (mres == 0) { 4784 if (obj->needed_filtees != NULL) { 4785 res = symlook_obj_load_filtees(req, &req1, obj, 4786 obj->needed_filtees); 4787 if (res == 0) { 4788 req->sym_out = req1.sym_out; 4789 req->defobj_out = req1.defobj_out; 4790 } 4791 return (res); 4792 } 4793 if (obj->needed_aux_filtees != NULL) { 4794 res = symlook_obj_load_filtees(req, &req1, obj, 4795 obj->needed_aux_filtees); 4796 if (res == 0) { 4797 req->sym_out = req1.sym_out; 4798 req->defobj_out = req1.defobj_out; 4799 return (res); 4800 } 4801 } 4802 } 4803 return (mres); 4804 } 4805 4806 /* Symbol match routine common to both hash functions */ 4807 static bool 4808 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4809 const unsigned long symnum) 4810 { 4811 Elf_Versym verndx; 4812 const Elf_Sym *symp; 4813 const char *strp; 4814 4815 symp = obj->symtab + symnum; 4816 strp = obj->strtab + symp->st_name; 4817 4818 switch (ELF_ST_TYPE(symp->st_info)) { 4819 case STT_FUNC: 4820 case STT_NOTYPE: 4821 case STT_OBJECT: 4822 case STT_COMMON: 4823 case STT_GNU_IFUNC: 4824 if (symp->st_value == 0) 4825 return (false); 4826 /* fallthrough */ 4827 case STT_TLS: 4828 if (symp->st_shndx != SHN_UNDEF) 4829 break; 4830 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4831 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4832 break; 4833 /* fallthrough */ 4834 default: 4835 return (false); 4836 } 4837 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4838 return (false); 4839 4840 if (req->ventry == NULL) { 4841 if (obj->versyms != NULL) { 4842 verndx = VER_NDX(obj->versyms[symnum]); 4843 if (verndx > obj->vernum) { 4844 _rtld_error( 4845 "%s: symbol %s references wrong version %d", 4846 obj->path, obj->strtab + symnum, verndx); 4847 return (false); 4848 } 4849 /* 4850 * If we are not called from dlsym (i.e. this 4851 * is a normal relocation from unversioned 4852 * binary), accept the symbol immediately if 4853 * it happens to have first version after this 4854 * shared object became versioned. Otherwise, 4855 * if symbol is versioned and not hidden, 4856 * remember it. If it is the only symbol with 4857 * this name exported by the shared object, it 4858 * will be returned as a match by the calling 4859 * function. If symbol is global (verndx < 2) 4860 * accept it unconditionally. 4861 */ 4862 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4863 verndx == VER_NDX_GIVEN) { 4864 result->sym_out = symp; 4865 return (true); 4866 } 4867 else if (verndx >= VER_NDX_GIVEN) { 4868 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4869 == 0) { 4870 if (result->vsymp == NULL) 4871 result->vsymp = symp; 4872 result->vcount++; 4873 } 4874 return (false); 4875 } 4876 } 4877 result->sym_out = symp; 4878 return (true); 4879 } 4880 if (obj->versyms == NULL) { 4881 if (object_match_name(obj, req->ventry->name)) { 4882 _rtld_error("%s: object %s should provide version %s " 4883 "for symbol %s", obj_rtld.path, obj->path, 4884 req->ventry->name, obj->strtab + symnum); 4885 return (false); 4886 } 4887 } else { 4888 verndx = VER_NDX(obj->versyms[symnum]); 4889 if (verndx > obj->vernum) { 4890 _rtld_error("%s: symbol %s references wrong version %d", 4891 obj->path, obj->strtab + symnum, verndx); 4892 return (false); 4893 } 4894 if (obj->vertab[verndx].hash != req->ventry->hash || 4895 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4896 /* 4897 * Version does not match. Look if this is a 4898 * global symbol and if it is not hidden. If 4899 * global symbol (verndx < 2) is available, 4900 * use it. Do not return symbol if we are 4901 * called by dlvsym, because dlvsym looks for 4902 * a specific version and default one is not 4903 * what dlvsym wants. 4904 */ 4905 if ((req->flags & SYMLOOK_DLSYM) || 4906 (verndx >= VER_NDX_GIVEN) || 4907 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4908 return (false); 4909 } 4910 } 4911 result->sym_out = symp; 4912 return (true); 4913 } 4914 4915 /* 4916 * Search for symbol using SysV hash function. 4917 * obj->buckets is known not to be NULL at this point; the test for this was 4918 * performed with the obj->valid_hash_sysv assignment. 4919 */ 4920 static int 4921 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4922 { 4923 unsigned long symnum; 4924 Sym_Match_Result matchres; 4925 4926 matchres.sym_out = NULL; 4927 matchres.vsymp = NULL; 4928 matchres.vcount = 0; 4929 4930 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4931 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4932 if (symnum >= obj->nchains) 4933 return (ESRCH); /* Bad object */ 4934 4935 if (matched_symbol(req, obj, &matchres, symnum)) { 4936 req->sym_out = matchres.sym_out; 4937 req->defobj_out = obj; 4938 return (0); 4939 } 4940 } 4941 if (matchres.vcount == 1) { 4942 req->sym_out = matchres.vsymp; 4943 req->defobj_out = obj; 4944 return (0); 4945 } 4946 return (ESRCH); 4947 } 4948 4949 /* Search for symbol using GNU hash function */ 4950 static int 4951 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4952 { 4953 Elf_Addr bloom_word; 4954 const Elf32_Word *hashval; 4955 Elf32_Word bucket; 4956 Sym_Match_Result matchres; 4957 unsigned int h1, h2; 4958 unsigned long symnum; 4959 4960 matchres.sym_out = NULL; 4961 matchres.vsymp = NULL; 4962 matchres.vcount = 0; 4963 4964 /* Pick right bitmask word from Bloom filter array */ 4965 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4966 obj->maskwords_bm_gnu]; 4967 4968 /* Calculate modulus word size of gnu hash and its derivative */ 4969 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4970 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4971 4972 /* Filter out the "definitely not in set" queries */ 4973 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4974 return (ESRCH); 4975 4976 /* Locate hash chain and corresponding value element*/ 4977 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4978 if (bucket == 0) 4979 return (ESRCH); 4980 hashval = &obj->chain_zero_gnu[bucket]; 4981 do { 4982 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4983 symnum = hashval - obj->chain_zero_gnu; 4984 if (matched_symbol(req, obj, &matchres, symnum)) { 4985 req->sym_out = matchres.sym_out; 4986 req->defobj_out = obj; 4987 return (0); 4988 } 4989 } 4990 } while ((*hashval++ & 1) == 0); 4991 if (matchres.vcount == 1) { 4992 req->sym_out = matchres.vsymp; 4993 req->defobj_out = obj; 4994 return (0); 4995 } 4996 return (ESRCH); 4997 } 4998 4999 static void 5000 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 5001 { 5002 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 5003 if (*main_local == NULL) 5004 *main_local = ""; 5005 5006 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 5007 if (*fmt1 == NULL) 5008 *fmt1 = "\t%o => %p (%x)\n"; 5009 5010 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 5011 if (*fmt2 == NULL) 5012 *fmt2 = "\t%o (%x)\n"; 5013 } 5014 5015 static void 5016 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 5017 const char *main_local, const char *fmt1, const char *fmt2) 5018 { 5019 const char *fmt; 5020 int c; 5021 5022 if (fmt1 == NULL) 5023 fmt = fmt2; 5024 else 5025 /* XXX bogus */ 5026 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 5027 5028 while ((c = *fmt++) != '\0') { 5029 switch (c) { 5030 default: 5031 rtld_putchar(c); 5032 continue; 5033 case '\\': 5034 switch (c = *fmt) { 5035 case '\0': 5036 continue; 5037 case 'n': 5038 rtld_putchar('\n'); 5039 break; 5040 case 't': 5041 rtld_putchar('\t'); 5042 break; 5043 } 5044 break; 5045 case '%': 5046 switch (c = *fmt) { 5047 case '\0': 5048 continue; 5049 case '%': 5050 default: 5051 rtld_putchar(c); 5052 break; 5053 case 'A': 5054 rtld_putstr(main_local); 5055 break; 5056 case 'a': 5057 rtld_putstr(obj_main->path); 5058 break; 5059 case 'o': 5060 rtld_putstr(name); 5061 break; 5062 case 'p': 5063 rtld_putstr(path); 5064 break; 5065 case 'x': 5066 rtld_printf("%p", obj != NULL ? 5067 obj->mapbase : NULL); 5068 break; 5069 } 5070 break; 5071 } 5072 ++fmt; 5073 } 5074 } 5075 5076 static void 5077 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5078 { 5079 const char *fmt1, *fmt2, *main_local; 5080 const char *name, *path; 5081 bool first_spurious, list_containers; 5082 5083 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5084 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5085 5086 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5087 Needed_Entry *needed; 5088 5089 if (obj->marker) 5090 continue; 5091 if (list_containers && obj->needed != NULL) 5092 rtld_printf("%s:\n", obj->path); 5093 for (needed = obj->needed; needed; needed = needed->next) { 5094 if (needed->obj != NULL) { 5095 if (needed->obj->traced && !list_containers) 5096 continue; 5097 needed->obj->traced = true; 5098 path = needed->obj->path; 5099 } else 5100 path = "not found"; 5101 5102 name = obj->strtab + needed->name; 5103 trace_print_obj(needed->obj, name, path, main_local, 5104 fmt1, fmt2); 5105 } 5106 } 5107 5108 if (show_preload) { 5109 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5110 fmt2 = "\t%p (%x)\n"; 5111 first_spurious = true; 5112 5113 TAILQ_FOREACH(obj, &obj_list, next) { 5114 if (obj->marker || obj == obj_main || obj->traced) 5115 continue; 5116 5117 if (list_containers && first_spurious) { 5118 rtld_printf("[preloaded]\n"); 5119 first_spurious = false; 5120 } 5121 5122 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5123 name = fname == NULL ? "<unknown>" : fname->name; 5124 trace_print_obj(obj, name, obj->path, main_local, 5125 NULL, fmt2); 5126 } 5127 } 5128 } 5129 5130 /* 5131 * Unload a dlopened object and its dependencies from memory and from 5132 * our data structures. It is assumed that the DAG rooted in the 5133 * object has already been unreferenced, and that the object has a 5134 * reference count of 0. 5135 */ 5136 static void 5137 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5138 { 5139 Obj_Entry marker, *obj, *next; 5140 5141 assert(root->refcount == 0); 5142 5143 /* 5144 * Pass over the DAG removing unreferenced objects from 5145 * appropriate lists. 5146 */ 5147 unlink_object(root); 5148 5149 /* Unmap all objects that are no longer referenced. */ 5150 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5151 next = TAILQ_NEXT(obj, next); 5152 if (obj->marker || obj->refcount != 0) 5153 continue; 5154 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5155 obj->mapsize, 0, obj->path); 5156 dbg("unloading \"%s\"", obj->path); 5157 /* 5158 * Unlink the object now to prevent new references from 5159 * being acquired while the bind lock is dropped in 5160 * recursive dlclose() invocations. 5161 */ 5162 TAILQ_REMOVE(&obj_list, obj, next); 5163 obj_count--; 5164 5165 if (obj->filtees_loaded) { 5166 if (next != NULL) { 5167 init_marker(&marker); 5168 TAILQ_INSERT_BEFORE(next, &marker, next); 5169 unload_filtees(obj, lockstate); 5170 next = TAILQ_NEXT(&marker, next); 5171 TAILQ_REMOVE(&obj_list, &marker, next); 5172 } else 5173 unload_filtees(obj, lockstate); 5174 } 5175 release_object(obj); 5176 } 5177 } 5178 5179 static void 5180 unlink_object(Obj_Entry *root) 5181 { 5182 Objlist_Entry *elm; 5183 5184 if (root->refcount == 0) { 5185 /* Remove the object from the RTLD_GLOBAL list. */ 5186 objlist_remove(&list_global, root); 5187 5188 /* Remove the object from all objects' DAG lists. */ 5189 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5190 objlist_remove(&elm->obj->dldags, root); 5191 if (elm->obj != root) 5192 unlink_object(elm->obj); 5193 } 5194 } 5195 } 5196 5197 static void 5198 ref_dag(Obj_Entry *root) 5199 { 5200 Objlist_Entry *elm; 5201 5202 assert(root->dag_inited); 5203 STAILQ_FOREACH(elm, &root->dagmembers, link) 5204 elm->obj->refcount++; 5205 } 5206 5207 static void 5208 unref_dag(Obj_Entry *root) 5209 { 5210 Objlist_Entry *elm; 5211 5212 assert(root->dag_inited); 5213 STAILQ_FOREACH(elm, &root->dagmembers, link) 5214 elm->obj->refcount--; 5215 } 5216 5217 /* 5218 * Common code for MD __tls_get_addr(). 5219 */ 5220 static void * 5221 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5222 { 5223 Elf_Addr *newdtv, *dtv; 5224 RtldLockState lockstate; 5225 int to_copy; 5226 5227 dtv = *dtvp; 5228 /* Check dtv generation in case new modules have arrived */ 5229 if (dtv[0] != tls_dtv_generation) { 5230 if (!locked) 5231 wlock_acquire(rtld_bind_lock, &lockstate); 5232 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5233 to_copy = dtv[1]; 5234 if (to_copy > tls_max_index) 5235 to_copy = tls_max_index; 5236 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5237 newdtv[0] = tls_dtv_generation; 5238 newdtv[1] = tls_max_index; 5239 free(dtv); 5240 if (!locked) 5241 lock_release(rtld_bind_lock, &lockstate); 5242 dtv = *dtvp = newdtv; 5243 } 5244 5245 /* Dynamically allocate module TLS if necessary */ 5246 if (dtv[index + 1] == 0) { 5247 /* Signal safe, wlock will block out signals. */ 5248 if (!locked) 5249 wlock_acquire(rtld_bind_lock, &lockstate); 5250 if (!dtv[index + 1]) 5251 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5252 if (!locked) 5253 lock_release(rtld_bind_lock, &lockstate); 5254 } 5255 return ((void *)(dtv[index + 1] + offset)); 5256 } 5257 5258 void * 5259 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5260 { 5261 uintptr_t *dtv; 5262 5263 dtv = *dtvp; 5264 /* Check dtv generation in case new modules have arrived */ 5265 if (__predict_true(dtv[0] == tls_dtv_generation && 5266 dtv[index + 1] != 0)) 5267 return ((void *)(dtv[index + 1] + offset)); 5268 return (tls_get_addr_slow(dtvp, index, offset, false)); 5269 } 5270 5271 #ifdef TLS_VARIANT_I 5272 5273 /* 5274 * Return pointer to allocated TLS block 5275 */ 5276 static void * 5277 get_tls_block_ptr(void *tcb, size_t tcbsize) 5278 { 5279 size_t extra_size, post_size, pre_size, tls_block_size; 5280 size_t tls_init_align; 5281 5282 tls_init_align = MAX(obj_main->tlsalign, 1); 5283 5284 /* Compute fragments sizes. */ 5285 extra_size = tcbsize - TLS_TCB_SIZE; 5286 post_size = calculate_tls_post_size(tls_init_align); 5287 tls_block_size = tcbsize + post_size; 5288 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5289 5290 return ((char *)tcb - pre_size - extra_size); 5291 } 5292 5293 /* 5294 * Allocate Static TLS using the Variant I method. 5295 * 5296 * For details on the layout, see lib/libc/gen/tls.c. 5297 * 5298 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5299 * it is based on tls_last_offset, and TLS offsets here are really TCB 5300 * offsets, whereas libc's tls_static_space is just the executable's static 5301 * TLS segment. 5302 */ 5303 void * 5304 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5305 { 5306 Obj_Entry *obj; 5307 char *tls_block; 5308 Elf_Addr *dtv, **tcb; 5309 Elf_Addr addr; 5310 Elf_Addr i; 5311 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5312 size_t tls_init_align, tls_init_offset; 5313 5314 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5315 return (oldtcb); 5316 5317 assert(tcbsize >= TLS_TCB_SIZE); 5318 maxalign = MAX(tcbalign, tls_static_max_align); 5319 tls_init_align = MAX(obj_main->tlsalign, 1); 5320 5321 /* Compute fragmets sizes. */ 5322 extra_size = tcbsize - TLS_TCB_SIZE; 5323 post_size = calculate_tls_post_size(tls_init_align); 5324 tls_block_size = tcbsize + post_size; 5325 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5326 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5327 5328 /* Allocate whole TLS block */ 5329 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5330 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5331 5332 if (oldtcb != NULL) { 5333 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5334 tls_static_space); 5335 free(get_tls_block_ptr(oldtcb, tcbsize)); 5336 5337 /* Adjust the DTV. */ 5338 dtv = tcb[0]; 5339 for (i = 0; i < dtv[1]; i++) { 5340 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5341 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5342 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5343 } 5344 } 5345 } else { 5346 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5347 tcb[0] = dtv; 5348 dtv[0] = tls_dtv_generation; 5349 dtv[1] = tls_max_index; 5350 5351 for (obj = globallist_curr(objs); obj != NULL; 5352 obj = globallist_next(obj)) { 5353 if (obj->tlsoffset == 0) 5354 continue; 5355 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5356 addr = (Elf_Addr)tcb + obj->tlsoffset; 5357 if (tls_init_offset > 0) 5358 memset((void *)addr, 0, tls_init_offset); 5359 if (obj->tlsinitsize > 0) { 5360 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5361 obj->tlsinitsize); 5362 } 5363 if (obj->tlssize > obj->tlsinitsize) { 5364 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5365 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5366 } 5367 dtv[obj->tlsindex + 1] = addr; 5368 } 5369 } 5370 5371 return (tcb); 5372 } 5373 5374 void 5375 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5376 { 5377 Elf_Addr *dtv; 5378 Elf_Addr tlsstart, tlsend; 5379 size_t post_size; 5380 size_t dtvsize, i, tls_init_align __unused; 5381 5382 assert(tcbsize >= TLS_TCB_SIZE); 5383 tls_init_align = MAX(obj_main->tlsalign, 1); 5384 5385 /* Compute fragments sizes. */ 5386 post_size = calculate_tls_post_size(tls_init_align); 5387 5388 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5389 tlsend = (Elf_Addr)tcb + tls_static_space; 5390 5391 dtv = *(Elf_Addr **)tcb; 5392 dtvsize = dtv[1]; 5393 for (i = 0; i < dtvsize; i++) { 5394 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5395 free((void*)dtv[i+2]); 5396 } 5397 } 5398 free(dtv); 5399 free(get_tls_block_ptr(tcb, tcbsize)); 5400 } 5401 5402 #endif /* TLS_VARIANT_I */ 5403 5404 #ifdef TLS_VARIANT_II 5405 5406 /* 5407 * Allocate Static TLS using the Variant II method. 5408 */ 5409 void * 5410 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5411 { 5412 Obj_Entry *obj; 5413 size_t size, ralign; 5414 char *tls; 5415 Elf_Addr *dtv, *olddtv; 5416 Elf_Addr segbase, oldsegbase, addr; 5417 size_t i; 5418 5419 ralign = tcbalign; 5420 if (tls_static_max_align > ralign) 5421 ralign = tls_static_max_align; 5422 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5423 5424 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5425 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5426 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5427 5428 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5429 ((Elf_Addr *)segbase)[0] = segbase; 5430 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5431 5432 dtv[0] = tls_dtv_generation; 5433 dtv[1] = tls_max_index; 5434 5435 if (oldtls) { 5436 /* 5437 * Copy the static TLS block over whole. 5438 */ 5439 oldsegbase = (Elf_Addr) oldtls; 5440 memcpy((void *)(segbase - tls_static_space), 5441 (const void *)(oldsegbase - tls_static_space), 5442 tls_static_space); 5443 5444 /* 5445 * If any dynamic TLS blocks have been created tls_get_addr(), 5446 * move them over. 5447 */ 5448 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5449 for (i = 0; i < olddtv[1]; i++) { 5450 if (olddtv[i + 2] < oldsegbase - size || 5451 olddtv[i + 2] > oldsegbase) { 5452 dtv[i + 2] = olddtv[i + 2]; 5453 olddtv[i + 2] = 0; 5454 } 5455 } 5456 5457 /* 5458 * We assume that this block was the one we created with 5459 * allocate_initial_tls(). 5460 */ 5461 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5462 } else { 5463 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5464 if (obj->marker || obj->tlsoffset == 0) 5465 continue; 5466 addr = segbase - obj->tlsoffset; 5467 memset((void *)(addr + obj->tlsinitsize), 5468 0, obj->tlssize - obj->tlsinitsize); 5469 if (obj->tlsinit) { 5470 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5471 obj->static_tls_copied = true; 5472 } 5473 dtv[obj->tlsindex + 1] = addr; 5474 } 5475 } 5476 5477 return ((void *)segbase); 5478 } 5479 5480 void 5481 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5482 { 5483 Elf_Addr* dtv; 5484 size_t size, ralign; 5485 int dtvsize, i; 5486 Elf_Addr tlsstart, tlsend; 5487 5488 /* 5489 * Figure out the size of the initial TLS block so that we can 5490 * find stuff which ___tls_get_addr() allocated dynamically. 5491 */ 5492 ralign = tcbalign; 5493 if (tls_static_max_align > ralign) 5494 ralign = tls_static_max_align; 5495 size = roundup(tls_static_space, ralign); 5496 5497 dtv = ((Elf_Addr **)tls)[1]; 5498 dtvsize = dtv[1]; 5499 tlsend = (Elf_Addr)tls; 5500 tlsstart = tlsend - size; 5501 for (i = 0; i < dtvsize; i++) { 5502 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5503 dtv[i + 2] > tlsend)) { 5504 free((void *)dtv[i + 2]); 5505 } 5506 } 5507 5508 free((void *)tlsstart); 5509 free((void *)dtv); 5510 } 5511 5512 #endif /* TLS_VARIANT_II */ 5513 5514 /* 5515 * Allocate TLS block for module with given index. 5516 */ 5517 void * 5518 allocate_module_tls(int index) 5519 { 5520 Obj_Entry *obj; 5521 char *p; 5522 5523 TAILQ_FOREACH(obj, &obj_list, next) { 5524 if (obj->marker) 5525 continue; 5526 if (obj->tlsindex == index) 5527 break; 5528 } 5529 if (obj == NULL) { 5530 _rtld_error("Can't find module with TLS index %d", index); 5531 rtld_die(); 5532 } 5533 5534 if (obj->tls_static) { 5535 #ifdef TLS_VARIANT_I 5536 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5537 #else 5538 p = (char *)_tcb_get() - obj->tlsoffset; 5539 #endif 5540 return (p); 5541 } 5542 5543 obj->tls_dynamic = true; 5544 5545 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5546 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5547 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5548 return (p); 5549 } 5550 5551 bool 5552 allocate_tls_offset(Obj_Entry *obj) 5553 { 5554 size_t off; 5555 5556 if (obj->tls_dynamic) 5557 return (false); 5558 5559 if (obj->tls_static) 5560 return (true); 5561 5562 if (obj->tlssize == 0) { 5563 obj->tls_static = true; 5564 return (true); 5565 } 5566 5567 if (tls_last_offset == 0) 5568 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5569 obj->tlspoffset); 5570 else 5571 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5572 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5573 5574 obj->tlsoffset = off; 5575 #ifdef TLS_VARIANT_I 5576 off += obj->tlssize; 5577 #endif 5578 5579 /* 5580 * If we have already fixed the size of the static TLS block, we 5581 * must stay within that size. When allocating the static TLS, we 5582 * leave a small amount of space spare to be used for dynamically 5583 * loading modules which use static TLS. 5584 */ 5585 if (tls_static_space != 0) { 5586 if (off > tls_static_space) 5587 return (false); 5588 } else if (obj->tlsalign > tls_static_max_align) { 5589 tls_static_max_align = obj->tlsalign; 5590 } 5591 5592 tls_last_offset = off; 5593 tls_last_size = obj->tlssize; 5594 obj->tls_static = true; 5595 5596 return (true); 5597 } 5598 5599 void 5600 free_tls_offset(Obj_Entry *obj) 5601 { 5602 5603 /* 5604 * If we were the last thing to allocate out of the static TLS 5605 * block, we give our space back to the 'allocator'. This is a 5606 * simplistic workaround to allow libGL.so.1 to be loaded and 5607 * unloaded multiple times. 5608 */ 5609 size_t off = obj->tlsoffset; 5610 #ifdef TLS_VARIANT_I 5611 off += obj->tlssize; 5612 #endif 5613 if (off == tls_last_offset) { 5614 tls_last_offset -= obj->tlssize; 5615 tls_last_size = 0; 5616 } 5617 } 5618 5619 void * 5620 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5621 { 5622 void *ret; 5623 RtldLockState lockstate; 5624 5625 wlock_acquire(rtld_bind_lock, &lockstate); 5626 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5627 tcbsize, tcbalign); 5628 lock_release(rtld_bind_lock, &lockstate); 5629 return (ret); 5630 } 5631 5632 void 5633 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5634 { 5635 RtldLockState lockstate; 5636 5637 wlock_acquire(rtld_bind_lock, &lockstate); 5638 free_tls(tcb, tcbsize, tcbalign); 5639 lock_release(rtld_bind_lock, &lockstate); 5640 } 5641 5642 static void 5643 object_add_name(Obj_Entry *obj, const char *name) 5644 { 5645 Name_Entry *entry; 5646 size_t len; 5647 5648 len = strlen(name); 5649 entry = malloc(sizeof(Name_Entry) + len); 5650 5651 if (entry != NULL) { 5652 strcpy(entry->name, name); 5653 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5654 } 5655 } 5656 5657 static int 5658 object_match_name(const Obj_Entry *obj, const char *name) 5659 { 5660 Name_Entry *entry; 5661 5662 STAILQ_FOREACH(entry, &obj->names, link) { 5663 if (strcmp(name, entry->name) == 0) 5664 return (1); 5665 } 5666 return (0); 5667 } 5668 5669 static Obj_Entry * 5670 locate_dependency(const Obj_Entry *obj, const char *name) 5671 { 5672 const Objlist_Entry *entry; 5673 const Needed_Entry *needed; 5674 5675 STAILQ_FOREACH(entry, &list_main, link) { 5676 if (object_match_name(entry->obj, name)) 5677 return (entry->obj); 5678 } 5679 5680 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5681 if (strcmp(obj->strtab + needed->name, name) == 0 || 5682 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5683 /* 5684 * If there is DT_NEEDED for the name we are looking for, 5685 * we are all set. Note that object might not be found if 5686 * dependency was not loaded yet, so the function can 5687 * return NULL here. This is expected and handled 5688 * properly by the caller. 5689 */ 5690 return (needed->obj); 5691 } 5692 } 5693 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5694 obj->path, name); 5695 rtld_die(); 5696 } 5697 5698 static int 5699 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5700 const Elf_Vernaux *vna) 5701 { 5702 const Elf_Verdef *vd; 5703 const char *vername; 5704 5705 vername = refobj->strtab + vna->vna_name; 5706 vd = depobj->verdef; 5707 if (vd == NULL) { 5708 _rtld_error("%s: version %s required by %s not defined", 5709 depobj->path, vername, refobj->path); 5710 return (-1); 5711 } 5712 for (;;) { 5713 if (vd->vd_version != VER_DEF_CURRENT) { 5714 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5715 depobj->path, vd->vd_version); 5716 return (-1); 5717 } 5718 if (vna->vna_hash == vd->vd_hash) { 5719 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5720 ((const char *)vd + vd->vd_aux); 5721 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5722 return (0); 5723 } 5724 if (vd->vd_next == 0) 5725 break; 5726 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5727 } 5728 if (vna->vna_flags & VER_FLG_WEAK) 5729 return (0); 5730 _rtld_error("%s: version %s required by %s not found", 5731 depobj->path, vername, refobj->path); 5732 return (-1); 5733 } 5734 5735 static int 5736 rtld_verify_object_versions(Obj_Entry *obj) 5737 { 5738 const Elf_Verneed *vn; 5739 const Elf_Verdef *vd; 5740 const Elf_Verdaux *vda; 5741 const Elf_Vernaux *vna; 5742 const Obj_Entry *depobj; 5743 int maxvernum, vernum; 5744 5745 if (obj->ver_checked) 5746 return (0); 5747 obj->ver_checked = true; 5748 5749 maxvernum = 0; 5750 /* 5751 * Walk over defined and required version records and figure out 5752 * max index used by any of them. Do very basic sanity checking 5753 * while there. 5754 */ 5755 vn = obj->verneed; 5756 while (vn != NULL) { 5757 if (vn->vn_version != VER_NEED_CURRENT) { 5758 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5759 obj->path, vn->vn_version); 5760 return (-1); 5761 } 5762 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5763 for (;;) { 5764 vernum = VER_NEED_IDX(vna->vna_other); 5765 if (vernum > maxvernum) 5766 maxvernum = vernum; 5767 if (vna->vna_next == 0) 5768 break; 5769 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5770 } 5771 if (vn->vn_next == 0) 5772 break; 5773 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5774 } 5775 5776 vd = obj->verdef; 5777 while (vd != NULL) { 5778 if (vd->vd_version != VER_DEF_CURRENT) { 5779 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5780 obj->path, vd->vd_version); 5781 return (-1); 5782 } 5783 vernum = VER_DEF_IDX(vd->vd_ndx); 5784 if (vernum > maxvernum) 5785 maxvernum = vernum; 5786 if (vd->vd_next == 0) 5787 break; 5788 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5789 } 5790 5791 if (maxvernum == 0) 5792 return (0); 5793 5794 /* 5795 * Store version information in array indexable by version index. 5796 * Verify that object version requirements are satisfied along the 5797 * way. 5798 */ 5799 obj->vernum = maxvernum + 1; 5800 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5801 5802 vd = obj->verdef; 5803 while (vd != NULL) { 5804 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5805 vernum = VER_DEF_IDX(vd->vd_ndx); 5806 assert(vernum <= maxvernum); 5807 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5808 obj->vertab[vernum].hash = vd->vd_hash; 5809 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5810 obj->vertab[vernum].file = NULL; 5811 obj->vertab[vernum].flags = 0; 5812 } 5813 if (vd->vd_next == 0) 5814 break; 5815 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5816 } 5817 5818 vn = obj->verneed; 5819 while (vn != NULL) { 5820 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5821 if (depobj == NULL) 5822 return (-1); 5823 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5824 for (;;) { 5825 if (check_object_provided_version(obj, depobj, vna)) 5826 return (-1); 5827 vernum = VER_NEED_IDX(vna->vna_other); 5828 assert(vernum <= maxvernum); 5829 obj->vertab[vernum].hash = vna->vna_hash; 5830 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5831 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5832 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5833 VER_INFO_HIDDEN : 0; 5834 if (vna->vna_next == 0) 5835 break; 5836 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5837 } 5838 if (vn->vn_next == 0) 5839 break; 5840 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5841 } 5842 return (0); 5843 } 5844 5845 static int 5846 rtld_verify_versions(const Objlist *objlist) 5847 { 5848 Objlist_Entry *entry; 5849 int rc; 5850 5851 rc = 0; 5852 STAILQ_FOREACH(entry, objlist, link) { 5853 /* 5854 * Skip dummy objects or objects that have their version requirements 5855 * already checked. 5856 */ 5857 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5858 continue; 5859 if (rtld_verify_object_versions(entry->obj) == -1) { 5860 rc = -1; 5861 if (ld_tracing == NULL) 5862 break; 5863 } 5864 } 5865 if (rc == 0 || ld_tracing != NULL) 5866 rc = rtld_verify_object_versions(&obj_rtld); 5867 return (rc); 5868 } 5869 5870 const Ver_Entry * 5871 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5872 { 5873 Elf_Versym vernum; 5874 5875 if (obj->vertab) { 5876 vernum = VER_NDX(obj->versyms[symnum]); 5877 if (vernum >= obj->vernum) { 5878 _rtld_error("%s: symbol %s has wrong verneed value %d", 5879 obj->path, obj->strtab + symnum, vernum); 5880 } else if (obj->vertab[vernum].hash != 0) { 5881 return (&obj->vertab[vernum]); 5882 } 5883 } 5884 return (NULL); 5885 } 5886 5887 int 5888 _rtld_get_stack_prot(void) 5889 { 5890 5891 return (stack_prot); 5892 } 5893 5894 int 5895 _rtld_is_dlopened(void *arg) 5896 { 5897 Obj_Entry *obj; 5898 RtldLockState lockstate; 5899 int res; 5900 5901 rlock_acquire(rtld_bind_lock, &lockstate); 5902 obj = dlcheck(arg); 5903 if (obj == NULL) 5904 obj = obj_from_addr(arg); 5905 if (obj == NULL) { 5906 _rtld_error("No shared object contains address"); 5907 lock_release(rtld_bind_lock, &lockstate); 5908 return (-1); 5909 } 5910 res = obj->dlopened ? 1 : 0; 5911 lock_release(rtld_bind_lock, &lockstate); 5912 return (res); 5913 } 5914 5915 static int 5916 obj_remap_relro(Obj_Entry *obj, int prot) 5917 { 5918 5919 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5920 prot) == -1) { 5921 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5922 obj->path, prot, rtld_strerror(errno)); 5923 return (-1); 5924 } 5925 return (0); 5926 } 5927 5928 static int 5929 obj_disable_relro(Obj_Entry *obj) 5930 { 5931 5932 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5933 } 5934 5935 static int 5936 obj_enforce_relro(Obj_Entry *obj) 5937 { 5938 5939 return (obj_remap_relro(obj, PROT_READ)); 5940 } 5941 5942 static void 5943 map_stacks_exec(RtldLockState *lockstate) 5944 { 5945 void (*thr_map_stacks_exec)(void); 5946 5947 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5948 return; 5949 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5950 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5951 if (thr_map_stacks_exec != NULL) { 5952 stack_prot |= PROT_EXEC; 5953 thr_map_stacks_exec(); 5954 } 5955 } 5956 5957 static void 5958 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5959 { 5960 Objlist_Entry *elm; 5961 Obj_Entry *obj; 5962 void (*distrib)(size_t, void *, size_t, size_t); 5963 5964 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5965 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5966 if (distrib == NULL) 5967 return; 5968 STAILQ_FOREACH(elm, list, link) { 5969 obj = elm->obj; 5970 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5971 continue; 5972 lock_release(rtld_bind_lock, lockstate); 5973 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5974 obj->tlssize); 5975 wlock_acquire(rtld_bind_lock, lockstate); 5976 obj->static_tls_copied = true; 5977 } 5978 } 5979 5980 void 5981 symlook_init(SymLook *dst, const char *name) 5982 { 5983 5984 bzero(dst, sizeof(*dst)); 5985 dst->name = name; 5986 dst->hash = elf_hash(name); 5987 dst->hash_gnu = gnu_hash(name); 5988 } 5989 5990 static void 5991 symlook_init_from_req(SymLook *dst, const SymLook *src) 5992 { 5993 5994 dst->name = src->name; 5995 dst->hash = src->hash; 5996 dst->hash_gnu = src->hash_gnu; 5997 dst->ventry = src->ventry; 5998 dst->flags = src->flags; 5999 dst->defobj_out = NULL; 6000 dst->sym_out = NULL; 6001 dst->lockstate = src->lockstate; 6002 } 6003 6004 static int 6005 open_binary_fd(const char *argv0, bool search_in_path, 6006 const char **binpath_res) 6007 { 6008 char *binpath, *pathenv, *pe, *res1; 6009 const char *res; 6010 int fd; 6011 6012 binpath = NULL; 6013 res = NULL; 6014 if (search_in_path && strchr(argv0, '/') == NULL) { 6015 binpath = xmalloc(PATH_MAX); 6016 pathenv = getenv("PATH"); 6017 if (pathenv == NULL) { 6018 _rtld_error("-p and no PATH environment variable"); 6019 rtld_die(); 6020 } 6021 pathenv = strdup(pathenv); 6022 if (pathenv == NULL) { 6023 _rtld_error("Cannot allocate memory"); 6024 rtld_die(); 6025 } 6026 fd = -1; 6027 errno = ENOENT; 6028 while ((pe = strsep(&pathenv, ":")) != NULL) { 6029 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 6030 continue; 6031 if (binpath[0] != '\0' && 6032 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 6033 continue; 6034 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 6035 continue; 6036 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 6037 if (fd != -1 || errno != ENOENT) { 6038 res = binpath; 6039 break; 6040 } 6041 } 6042 free(pathenv); 6043 } else { 6044 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 6045 res = argv0; 6046 } 6047 6048 if (fd == -1) { 6049 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 6050 rtld_die(); 6051 } 6052 if (res != NULL && res[0] != '/') { 6053 res1 = xmalloc(PATH_MAX); 6054 if (realpath(res, res1) != NULL) { 6055 if (res != argv0) 6056 free(__DECONST(char *, res)); 6057 res = res1; 6058 } else { 6059 free(res1); 6060 } 6061 } 6062 *binpath_res = res; 6063 return (fd); 6064 } 6065 6066 /* 6067 * Parse a set of command-line arguments. 6068 */ 6069 static int 6070 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6071 const char **argv0, bool *dir_ignore) 6072 { 6073 const char *arg; 6074 char machine[64]; 6075 size_t sz; 6076 int arglen, fd, i, j, mib[2]; 6077 char opt; 6078 bool seen_b, seen_f; 6079 6080 dbg("Parsing command-line arguments"); 6081 *use_pathp = false; 6082 *fdp = -1; 6083 *dir_ignore = false; 6084 seen_b = seen_f = false; 6085 6086 for (i = 1; i < argc; i++ ) { 6087 arg = argv[i]; 6088 dbg("argv[%d]: '%s'", i, arg); 6089 6090 /* 6091 * rtld arguments end with an explicit "--" or with the first 6092 * non-prefixed argument. 6093 */ 6094 if (strcmp(arg, "--") == 0) { 6095 i++; 6096 break; 6097 } 6098 if (arg[0] != '-') 6099 break; 6100 6101 /* 6102 * All other arguments are single-character options that can 6103 * be combined, so we need to search through `arg` for them. 6104 */ 6105 arglen = strlen(arg); 6106 for (j = 1; j < arglen; j++) { 6107 opt = arg[j]; 6108 if (opt == 'h') { 6109 print_usage(argv[0]); 6110 _exit(0); 6111 } else if (opt == 'b') { 6112 if (seen_f) { 6113 _rtld_error("Both -b and -f specified"); 6114 rtld_die(); 6115 } 6116 if (j != arglen - 1) { 6117 _rtld_error("Invalid options: %s", arg); 6118 rtld_die(); 6119 } 6120 i++; 6121 *argv0 = argv[i]; 6122 seen_b = true; 6123 break; 6124 } else if (opt == 'd') { 6125 *dir_ignore = true; 6126 } else if (opt == 'f') { 6127 if (seen_b) { 6128 _rtld_error("Both -b and -f specified"); 6129 rtld_die(); 6130 } 6131 6132 /* 6133 * -f XX can be used to specify a 6134 * descriptor for the binary named at 6135 * the command line (i.e., the later 6136 * argument will specify the process 6137 * name but the descriptor is what 6138 * will actually be executed). 6139 * 6140 * -f must be the last option in the 6141 * group, e.g., -abcf <fd>. 6142 */ 6143 if (j != arglen - 1) { 6144 _rtld_error("Invalid options: %s", arg); 6145 rtld_die(); 6146 } 6147 i++; 6148 fd = parse_integer(argv[i]); 6149 if (fd == -1) { 6150 _rtld_error( 6151 "Invalid file descriptor: '%s'", 6152 argv[i]); 6153 rtld_die(); 6154 } 6155 *fdp = fd; 6156 seen_f = true; 6157 break; 6158 } else if (opt == 'o') { 6159 struct ld_env_var_desc *l; 6160 char *n, *v; 6161 u_int ll; 6162 6163 if (j != arglen - 1) { 6164 _rtld_error("Invalid options: %s", arg); 6165 rtld_die(); 6166 } 6167 i++; 6168 n = argv[i]; 6169 v = strchr(n, '='); 6170 if (v == NULL) { 6171 _rtld_error("No '=' in -o parameter"); 6172 rtld_die(); 6173 } 6174 for (ll = 0; ll < nitems(ld_env_vars); ll++) { 6175 l = &ld_env_vars[ll]; 6176 if (v - n == (ptrdiff_t)strlen(l->n) && 6177 strncmp(n, l->n, v - n) == 0) { 6178 l->val = v + 1; 6179 break; 6180 } 6181 } 6182 if (ll == nitems(ld_env_vars)) { 6183 _rtld_error("Unknown LD_ option %s", 6184 n); 6185 rtld_die(); 6186 } 6187 } else if (opt == 'p') { 6188 *use_pathp = true; 6189 } else if (opt == 'u') { 6190 u_int ll; 6191 6192 for (ll = 0; ll < nitems(ld_env_vars); ll++) 6193 ld_env_vars[ll].val = NULL; 6194 } else if (opt == 'v') { 6195 machine[0] = '\0'; 6196 mib[0] = CTL_HW; 6197 mib[1] = HW_MACHINE; 6198 sz = sizeof(machine); 6199 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6200 ld_elf_hints_path = ld_get_env_var( 6201 LD_ELF_HINTS_PATH); 6202 set_ld_elf_hints_path(); 6203 rtld_printf( 6204 "FreeBSD ld-elf.so.1 %s\n" 6205 "FreeBSD_version %d\n" 6206 "Default lib path %s\n" 6207 "Hints lib path %s\n" 6208 "Env prefix %s\n" 6209 "Default hint file %s\n" 6210 "Hint file %s\n" 6211 "libmap file %s\n" 6212 "Optional static TLS size %zd bytes\n", 6213 machine, 6214 __FreeBSD_version, ld_standard_library_path, 6215 gethints(false), 6216 ld_env_prefix, ld_elf_hints_default, 6217 ld_elf_hints_path, 6218 ld_path_libmap_conf, 6219 ld_static_tls_extra); 6220 _exit(0); 6221 } else { 6222 _rtld_error("Invalid argument: '%s'", arg); 6223 print_usage(argv[0]); 6224 rtld_die(); 6225 } 6226 } 6227 } 6228 6229 if (!seen_b) 6230 *argv0 = argv[i]; 6231 return (i); 6232 } 6233 6234 /* 6235 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6236 */ 6237 static int 6238 parse_integer(const char *str) 6239 { 6240 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6241 const char *orig; 6242 int n; 6243 char c; 6244 6245 orig = str; 6246 n = 0; 6247 for (c = *str; c != '\0'; c = *++str) { 6248 if (c < '0' || c > '9') 6249 return (-1); 6250 6251 n *= RADIX; 6252 n += c - '0'; 6253 } 6254 6255 /* Make sure we actually parsed something. */ 6256 if (str == orig) 6257 return (-1); 6258 return (n); 6259 } 6260 6261 static void 6262 print_usage(const char *argv0) 6263 { 6264 6265 rtld_printf( 6266 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6267 "\n" 6268 "Options:\n" 6269 " -h Display this help message\n" 6270 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6271 " -d Ignore lack of exec permissions for the binary\n" 6272 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6273 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n" 6274 " -p Search in PATH for named binary\n" 6275 " -u Ignore LD_ environment variables\n" 6276 " -v Display identification information\n" 6277 " -- End of RTLD options\n" 6278 " <binary> Name of process to execute\n" 6279 " <args> Arguments to the executed process\n", argv0); 6280 } 6281 6282 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6283 static const struct auxfmt { 6284 const char *name; 6285 const char *fmt; 6286 } auxfmts[] = { 6287 AUXFMT(AT_NULL, NULL), 6288 AUXFMT(AT_IGNORE, NULL), 6289 AUXFMT(AT_EXECFD, "%ld"), 6290 AUXFMT(AT_PHDR, "%p"), 6291 AUXFMT(AT_PHENT, "%lu"), 6292 AUXFMT(AT_PHNUM, "%lu"), 6293 AUXFMT(AT_PAGESZ, "%lu"), 6294 AUXFMT(AT_BASE, "%#lx"), 6295 AUXFMT(AT_FLAGS, "%#lx"), 6296 AUXFMT(AT_ENTRY, "%p"), 6297 AUXFMT(AT_NOTELF, NULL), 6298 AUXFMT(AT_UID, "%ld"), 6299 AUXFMT(AT_EUID, "%ld"), 6300 AUXFMT(AT_GID, "%ld"), 6301 AUXFMT(AT_EGID, "%ld"), 6302 AUXFMT(AT_EXECPATH, "%s"), 6303 AUXFMT(AT_CANARY, "%p"), 6304 AUXFMT(AT_CANARYLEN, "%lu"), 6305 AUXFMT(AT_OSRELDATE, "%lu"), 6306 AUXFMT(AT_NCPUS, "%lu"), 6307 AUXFMT(AT_PAGESIZES, "%p"), 6308 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6309 AUXFMT(AT_TIMEKEEP, "%p"), 6310 AUXFMT(AT_STACKPROT, "%#lx"), 6311 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6312 AUXFMT(AT_HWCAP, "%#lx"), 6313 AUXFMT(AT_HWCAP2, "%#lx"), 6314 AUXFMT(AT_BSDFLAGS, "%#lx"), 6315 AUXFMT(AT_ARGC, "%lu"), 6316 AUXFMT(AT_ARGV, "%p"), 6317 AUXFMT(AT_ENVC, "%p"), 6318 AUXFMT(AT_ENVV, "%p"), 6319 AUXFMT(AT_PS_STRINGS, "%p"), 6320 AUXFMT(AT_FXRNG, "%p"), 6321 AUXFMT(AT_KPRELOAD, "%p"), 6322 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6323 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6324 }; 6325 6326 static bool 6327 is_ptr_fmt(const char *fmt) 6328 { 6329 char last; 6330 6331 last = fmt[strlen(fmt) - 1]; 6332 return (last == 'p' || last == 's'); 6333 } 6334 6335 static void 6336 dump_auxv(Elf_Auxinfo **aux_info) 6337 { 6338 Elf_Auxinfo *auxp; 6339 const struct auxfmt *fmt; 6340 int i; 6341 6342 for (i = 0; i < AT_COUNT; i++) { 6343 auxp = aux_info[i]; 6344 if (auxp == NULL) 6345 continue; 6346 fmt = &auxfmts[i]; 6347 if (fmt->fmt == NULL) 6348 continue; 6349 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6350 if (is_ptr_fmt(fmt->fmt)) { 6351 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6352 auxp->a_un.a_ptr); 6353 } else { 6354 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6355 auxp->a_un.a_val); 6356 } 6357 rtld_fdprintf(STDOUT_FILENO, "\n"); 6358 } 6359 } 6360 6361 /* 6362 * Overrides for libc_pic-provided functions. 6363 */ 6364 6365 int 6366 __getosreldate(void) 6367 { 6368 size_t len; 6369 int oid[2]; 6370 int error, osrel; 6371 6372 if (osreldate != 0) 6373 return (osreldate); 6374 6375 oid[0] = CTL_KERN; 6376 oid[1] = KERN_OSRELDATE; 6377 osrel = 0; 6378 len = sizeof(osrel); 6379 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6380 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6381 osreldate = osrel; 6382 return (osreldate); 6383 } 6384 const char * 6385 rtld_strerror(int errnum) 6386 { 6387 6388 if (errnum < 0 || errnum >= sys_nerr) 6389 return ("Unknown error"); 6390 return (sys_errlist[errnum]); 6391 } 6392 6393 char * 6394 getenv(const char *name) 6395 { 6396 return (__DECONST(char *, rtld_get_env_val(environ, name, 6397 strlen(name)))); 6398 } 6399 6400 /* malloc */ 6401 void * 6402 malloc(size_t nbytes) 6403 { 6404 6405 return (__crt_malloc(nbytes)); 6406 } 6407 6408 void * 6409 calloc(size_t num, size_t size) 6410 { 6411 6412 return (__crt_calloc(num, size)); 6413 } 6414 6415 void 6416 free(void *cp) 6417 { 6418 6419 __crt_free(cp); 6420 } 6421 6422 void * 6423 realloc(void *cp, size_t nbytes) 6424 { 6425 6426 return (__crt_realloc(cp, nbytes)); 6427 } 6428 6429 extern int _rtld_version__FreeBSD_version __exported; 6430 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6431 6432 extern char _rtld_version_laddr_offset __exported; 6433 char _rtld_version_laddr_offset; 6434 6435 extern char _rtld_version_dlpi_tls_data __exported; 6436 char _rtld_version_dlpi_tls_data; 6437