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