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