1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/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 2576 lock_restart_for_upgrade(lockstate); 2577 if (!obj->filtees_loaded) { 2578 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2579 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2580 obj->filtees_loaded = true; 2581 } 2582 } 2583 2584 static int 2585 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2586 { 2587 Obj_Entry *obj1; 2588 2589 for (; needed != NULL; needed = needed->next) { 2590 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2591 flags & ~RTLD_LO_NOLOAD); 2592 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2593 return (-1); 2594 } 2595 return (0); 2596 } 2597 2598 /* 2599 * Given a shared object, traverse its list of needed objects, and load 2600 * each of them. Returns 0 on success. Generates an error message and 2601 * returns -1 on failure. 2602 */ 2603 static int 2604 load_needed_objects(Obj_Entry *first, int flags) 2605 { 2606 Obj_Entry *obj; 2607 2608 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2609 if (obj->marker) 2610 continue; 2611 if (process_needed(obj, obj->needed, flags) == -1) 2612 return (-1); 2613 } 2614 return (0); 2615 } 2616 2617 static int 2618 load_preload_objects(const char *penv, bool isfd) 2619 { 2620 Obj_Entry *obj; 2621 const char *name; 2622 size_t len; 2623 char savech, *p, *psave; 2624 int fd; 2625 static const char delim[] = " \t:;"; 2626 2627 if (penv == NULL) 2628 return (0); 2629 2630 p = psave = xstrdup(penv); 2631 p += strspn(p, delim); 2632 while (*p != '\0') { 2633 len = strcspn(p, delim); 2634 2635 savech = p[len]; 2636 p[len] = '\0'; 2637 if (isfd) { 2638 name = NULL; 2639 fd = parse_integer(p); 2640 if (fd == -1) { 2641 free(psave); 2642 return (-1); 2643 } 2644 } else { 2645 name = p; 2646 fd = -1; 2647 } 2648 2649 obj = load_object(name, fd, NULL, 0); 2650 if (obj == NULL) { 2651 free(psave); 2652 return (-1); /* XXX - cleanup */ 2653 } 2654 obj->z_interpose = true; 2655 p[len] = savech; 2656 p += len; 2657 p += strspn(p, delim); 2658 } 2659 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2660 2661 free(psave); 2662 return (0); 2663 } 2664 2665 static const char * 2666 printable_path(const char *path) 2667 { 2668 2669 return (path == NULL ? "<unknown>" : path); 2670 } 2671 2672 /* 2673 * Load a shared object into memory, if it is not already loaded. The 2674 * object may be specified by name or by user-supplied file descriptor 2675 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2676 * duplicate is. 2677 * 2678 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2679 * on failure. 2680 */ 2681 static Obj_Entry * 2682 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2683 { 2684 Obj_Entry *obj; 2685 int fd; 2686 struct stat sb; 2687 char *path; 2688 2689 fd = -1; 2690 if (name != NULL) { 2691 TAILQ_FOREACH(obj, &obj_list, next) { 2692 if (obj->marker || obj->doomed) 2693 continue; 2694 if (object_match_name(obj, name)) 2695 return (obj); 2696 } 2697 2698 path = find_library(name, refobj, &fd); 2699 if (path == NULL) 2700 return (NULL); 2701 } else 2702 path = NULL; 2703 2704 if (fd >= 0) { 2705 /* 2706 * search_library_pathfds() opens a fresh file descriptor for the 2707 * library, so there is no need to dup(). 2708 */ 2709 } else if (fd_u == -1) { 2710 /* 2711 * If we didn't find a match by pathname, or the name is not 2712 * supplied, open the file and check again by device and inode. 2713 * This avoids false mismatches caused by multiple links or ".." 2714 * in pathnames. 2715 * 2716 * To avoid a race, we open the file and use fstat() rather than 2717 * using stat(). 2718 */ 2719 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2720 _rtld_error("Cannot open \"%s\"", path); 2721 free(path); 2722 return (NULL); 2723 } 2724 } else { 2725 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2726 if (fd == -1) { 2727 _rtld_error("Cannot dup fd"); 2728 free(path); 2729 return (NULL); 2730 } 2731 } 2732 if (fstat(fd, &sb) == -1) { 2733 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2734 close(fd); 2735 free(path); 2736 return (NULL); 2737 } 2738 TAILQ_FOREACH(obj, &obj_list, next) { 2739 if (obj->marker || obj->doomed) 2740 continue; 2741 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2742 break; 2743 } 2744 if (obj != NULL && name != NULL) { 2745 object_add_name(obj, name); 2746 free(path); 2747 close(fd); 2748 return (obj); 2749 } 2750 if (flags & RTLD_LO_NOLOAD) { 2751 free(path); 2752 close(fd); 2753 return (NULL); 2754 } 2755 2756 /* First use of this object, so we must map it in */ 2757 obj = do_load_object(fd, name, path, &sb, flags); 2758 if (obj == NULL) 2759 free(path); 2760 close(fd); 2761 2762 return (obj); 2763 } 2764 2765 static Obj_Entry * 2766 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2767 int flags) 2768 { 2769 Obj_Entry *obj; 2770 struct statfs fs; 2771 2772 /* 2773 * First, make sure that environment variables haven't been 2774 * used to circumvent the noexec flag on a filesystem. 2775 * We ignore fstatfs(2) failures, since fd might reference 2776 * not a file, e.g. shmfd. 2777 */ 2778 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2779 (fs.f_flags & MNT_NOEXEC) != 0) { 2780 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2781 return (NULL); 2782 } 2783 2784 dbg("loading \"%s\"", printable_path(path)); 2785 obj = map_object(fd, printable_path(path), sbp); 2786 if (obj == NULL) 2787 return (NULL); 2788 2789 /* 2790 * If DT_SONAME is present in the object, digest_dynamic2 already 2791 * added it to the object names. 2792 */ 2793 if (name != NULL) 2794 object_add_name(obj, name); 2795 obj->path = path; 2796 if (!digest_dynamic(obj, 0)) 2797 goto errp; 2798 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2799 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2800 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2801 dbg("refusing to load PIE executable \"%s\"", obj->path); 2802 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2803 goto errp; 2804 } 2805 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2806 RTLD_LO_DLOPEN) { 2807 dbg("refusing to load non-loadable \"%s\"", obj->path); 2808 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2809 goto errp; 2810 } 2811 2812 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2813 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2814 obj_count++; 2815 obj_loads++; 2816 linkmap_add(obj); /* for GDB & dlinfo() */ 2817 max_stack_flags |= obj->stack_flags; 2818 2819 dbg(" %p .. %p: %s", obj->mapbase, 2820 obj->mapbase + obj->mapsize - 1, obj->path); 2821 if (obj->textrel) 2822 dbg(" WARNING: %s has impure text", obj->path); 2823 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2824 obj->path); 2825 2826 return (obj); 2827 2828 errp: 2829 munmap(obj->mapbase, obj->mapsize); 2830 obj_free(obj); 2831 return (NULL); 2832 } 2833 2834 static int 2835 load_kpreload(const void *addr) 2836 { 2837 Obj_Entry *obj; 2838 const Elf_Ehdr *ehdr; 2839 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2840 static const char kname[] = "[vdso]"; 2841 2842 ehdr = addr; 2843 if (!check_elf_headers(ehdr, "kpreload")) 2844 return (-1); 2845 obj = obj_new(); 2846 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2847 obj->phdr = phdr; 2848 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2849 phlimit = phdr + ehdr->e_phnum; 2850 seg0 = segn = NULL; 2851 2852 for (; phdr < phlimit; phdr++) { 2853 switch (phdr->p_type) { 2854 case PT_DYNAMIC: 2855 phdyn = phdr; 2856 break; 2857 case PT_GNU_STACK: 2858 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2859 obj->stack_flags = phdr->p_flags; 2860 break; 2861 case PT_LOAD: 2862 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2863 seg0 = phdr; 2864 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2865 phdr->p_vaddr + phdr->p_memsz) 2866 segn = phdr; 2867 break; 2868 } 2869 } 2870 2871 obj->mapbase = __DECONST(caddr_t, addr); 2872 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2873 obj->vaddrbase = 0; 2874 obj->relocbase = obj->mapbase; 2875 2876 object_add_name(obj, kname); 2877 obj->path = xstrdup(kname); 2878 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2879 2880 if (!digest_dynamic(obj, 0)) { 2881 obj_free(obj); 2882 return (-1); 2883 } 2884 2885 /* 2886 * We assume that kernel-preloaded object does not need 2887 * relocation. It is currently written into read-only page, 2888 * handling relocations would mean we need to allocate at 2889 * least one additional page per AS. 2890 */ 2891 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2892 obj->path, obj->mapbase, obj->phdr, seg0, 2893 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2894 2895 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2896 obj_count++; 2897 obj_loads++; 2898 linkmap_add(obj); /* for GDB & dlinfo() */ 2899 max_stack_flags |= obj->stack_flags; 2900 2901 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2902 return (0); 2903 } 2904 2905 Obj_Entry * 2906 obj_from_addr(const void *addr) 2907 { 2908 Obj_Entry *obj; 2909 2910 TAILQ_FOREACH(obj, &obj_list, next) { 2911 if (obj->marker) 2912 continue; 2913 if (addr < (void *) obj->mapbase) 2914 continue; 2915 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2916 return obj; 2917 } 2918 return (NULL); 2919 } 2920 2921 static void 2922 preinit_main(void) 2923 { 2924 Elf_Addr *preinit_addr; 2925 int index; 2926 2927 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2928 if (preinit_addr == NULL) 2929 return; 2930 2931 for (index = 0; index < obj_main->preinit_array_num; index++) { 2932 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2933 dbg("calling preinit function for %s at %p", obj_main->path, 2934 (void *)preinit_addr[index]); 2935 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2936 0, 0, obj_main->path); 2937 call_init_pointer(obj_main, preinit_addr[index]); 2938 } 2939 } 2940 } 2941 2942 /* 2943 * Call the finalization functions for each of the objects in "list" 2944 * belonging to the DAG of "root" and referenced once. If NULL "root" 2945 * is specified, every finalization function will be called regardless 2946 * of the reference count and the list elements won't be freed. All of 2947 * the objects are expected to have non-NULL fini functions. 2948 */ 2949 static void 2950 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2951 { 2952 Objlist_Entry *elm; 2953 struct dlerror_save *saved_msg; 2954 Elf_Addr *fini_addr; 2955 int index; 2956 2957 assert(root == NULL || root->refcount == 1); 2958 2959 if (root != NULL) 2960 root->doomed = true; 2961 2962 /* 2963 * Preserve the current error message since a fini function might 2964 * call into the dynamic linker and overwrite it. 2965 */ 2966 saved_msg = errmsg_save(); 2967 do { 2968 STAILQ_FOREACH(elm, list, link) { 2969 if (root != NULL && (elm->obj->refcount != 1 || 2970 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2971 continue; 2972 /* Remove object from fini list to prevent recursive invocation. */ 2973 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2974 /* Ensure that new references cannot be acquired. */ 2975 elm->obj->doomed = true; 2976 2977 hold_object(elm->obj); 2978 lock_release(rtld_bind_lock, lockstate); 2979 /* 2980 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2981 * When this happens, DT_FINI_ARRAY is processed first. 2982 */ 2983 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2984 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2985 for (index = elm->obj->fini_array_num - 1; index >= 0; 2986 index--) { 2987 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2988 dbg("calling fini function for %s at %p", 2989 elm->obj->path, (void *)fini_addr[index]); 2990 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2991 (void *)fini_addr[index], 0, 0, elm->obj->path); 2992 call_initfini_pointer(elm->obj, fini_addr[index]); 2993 } 2994 } 2995 } 2996 if (elm->obj->fini != (Elf_Addr)NULL) { 2997 dbg("calling fini function for %s at %p", elm->obj->path, 2998 (void *)elm->obj->fini); 2999 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3000 0, 0, elm->obj->path); 3001 call_initfini_pointer(elm->obj, elm->obj->fini); 3002 } 3003 wlock_acquire(rtld_bind_lock, lockstate); 3004 unhold_object(elm->obj); 3005 /* No need to free anything if process is going down. */ 3006 if (root != NULL) 3007 free(elm); 3008 /* 3009 * We must restart the list traversal after every fini call 3010 * because a dlclose() call from the fini function or from 3011 * another thread might have modified the reference counts. 3012 */ 3013 break; 3014 } 3015 } while (elm != NULL); 3016 errmsg_restore(saved_msg); 3017 } 3018 3019 /* 3020 * Call the initialization functions for each of the objects in 3021 * "list". All of the objects are expected to have non-NULL init 3022 * functions. 3023 */ 3024 static void 3025 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3026 { 3027 Objlist_Entry *elm; 3028 Obj_Entry *obj; 3029 struct dlerror_save *saved_msg; 3030 Elf_Addr *init_addr; 3031 void (*reg)(void (*)(void)); 3032 int index; 3033 3034 /* 3035 * Clean init_scanned flag so that objects can be rechecked and 3036 * possibly initialized earlier if any of vectors called below 3037 * cause the change by using dlopen. 3038 */ 3039 TAILQ_FOREACH(obj, &obj_list, next) { 3040 if (obj->marker) 3041 continue; 3042 obj->init_scanned = false; 3043 } 3044 3045 /* 3046 * Preserve the current error message since an init function might 3047 * call into the dynamic linker and overwrite it. 3048 */ 3049 saved_msg = errmsg_save(); 3050 STAILQ_FOREACH(elm, list, link) { 3051 if (elm->obj->init_done) /* Initialized early. */ 3052 continue; 3053 /* 3054 * Race: other thread might try to use this object before current 3055 * one completes the initialization. Not much can be done here 3056 * without better locking. 3057 */ 3058 elm->obj->init_done = true; 3059 hold_object(elm->obj); 3060 reg = NULL; 3061 if (elm->obj == obj_main && obj_main->crt_no_init) { 3062 reg = (void (*)(void (*)(void)))get_program_var_addr( 3063 "__libc_atexit", lockstate); 3064 } 3065 lock_release(rtld_bind_lock, lockstate); 3066 if (reg != NULL) { 3067 reg(rtld_exit); 3068 rtld_exit_ptr = rtld_nop_exit; 3069 } 3070 3071 /* 3072 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3073 * When this happens, DT_INIT is processed first. 3074 */ 3075 if (elm->obj->init != (Elf_Addr)NULL) { 3076 dbg("calling init function for %s at %p", elm->obj->path, 3077 (void *)elm->obj->init); 3078 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3079 0, 0, elm->obj->path); 3080 call_init_pointer(elm->obj, elm->obj->init); 3081 } 3082 init_addr = (Elf_Addr *)elm->obj->init_array; 3083 if (init_addr != NULL) { 3084 for (index = 0; index < elm->obj->init_array_num; index++) { 3085 if (init_addr[index] != 0 && init_addr[index] != 1) { 3086 dbg("calling init function for %s at %p", elm->obj->path, 3087 (void *)init_addr[index]); 3088 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3089 (void *)init_addr[index], 0, 0, elm->obj->path); 3090 call_init_pointer(elm->obj, init_addr[index]); 3091 } 3092 } 3093 } 3094 wlock_acquire(rtld_bind_lock, lockstate); 3095 unhold_object(elm->obj); 3096 } 3097 errmsg_restore(saved_msg); 3098 } 3099 3100 static void 3101 objlist_clear(Objlist *list) 3102 { 3103 Objlist_Entry *elm; 3104 3105 while (!STAILQ_EMPTY(list)) { 3106 elm = STAILQ_FIRST(list); 3107 STAILQ_REMOVE_HEAD(list, link); 3108 free(elm); 3109 } 3110 } 3111 3112 static Objlist_Entry * 3113 objlist_find(Objlist *list, const Obj_Entry *obj) 3114 { 3115 Objlist_Entry *elm; 3116 3117 STAILQ_FOREACH(elm, list, link) 3118 if (elm->obj == obj) 3119 return elm; 3120 return (NULL); 3121 } 3122 3123 static void 3124 objlist_init(Objlist *list) 3125 { 3126 STAILQ_INIT(list); 3127 } 3128 3129 static void 3130 objlist_push_head(Objlist *list, Obj_Entry *obj) 3131 { 3132 Objlist_Entry *elm; 3133 3134 elm = NEW(Objlist_Entry); 3135 elm->obj = obj; 3136 STAILQ_INSERT_HEAD(list, elm, link); 3137 } 3138 3139 static void 3140 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3141 { 3142 Objlist_Entry *elm; 3143 3144 elm = NEW(Objlist_Entry); 3145 elm->obj = obj; 3146 STAILQ_INSERT_TAIL(list, elm, link); 3147 } 3148 3149 static void 3150 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3151 { 3152 Objlist_Entry *elm, *listelm; 3153 3154 STAILQ_FOREACH(listelm, list, link) { 3155 if (listelm->obj == listobj) 3156 break; 3157 } 3158 elm = NEW(Objlist_Entry); 3159 elm->obj = obj; 3160 if (listelm != NULL) 3161 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3162 else 3163 STAILQ_INSERT_TAIL(list, elm, link); 3164 } 3165 3166 static void 3167 objlist_remove(Objlist *list, Obj_Entry *obj) 3168 { 3169 Objlist_Entry *elm; 3170 3171 if ((elm = objlist_find(list, obj)) != NULL) { 3172 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3173 free(elm); 3174 } 3175 } 3176 3177 /* 3178 * Relocate dag rooted in the specified object. 3179 * Returns 0 on success, or -1 on failure. 3180 */ 3181 3182 static int 3183 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3184 int flags, RtldLockState *lockstate) 3185 { 3186 Objlist_Entry *elm; 3187 int error; 3188 3189 error = 0; 3190 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3191 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3192 lockstate); 3193 if (error == -1) 3194 break; 3195 } 3196 return (error); 3197 } 3198 3199 /* 3200 * Prepare for, or clean after, relocating an object marked with 3201 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3202 * segments are remapped read-write. After relocations are done, the 3203 * segment's permissions are returned back to the modes specified in 3204 * the phdrs. If any relocation happened, or always for wired 3205 * program, COW is triggered. 3206 */ 3207 static int 3208 reloc_textrel_prot(Obj_Entry *obj, bool before) 3209 { 3210 const Elf_Phdr *ph; 3211 void *base; 3212 size_t l, sz; 3213 int prot; 3214 3215 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3216 l--, ph++) { 3217 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3218 continue; 3219 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3220 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3221 rtld_trunc_page(ph->p_vaddr); 3222 prot = before ? (PROT_READ | PROT_WRITE) : 3223 convert_prot(ph->p_flags); 3224 if (mprotect(base, sz, prot) == -1) { 3225 _rtld_error("%s: Cannot write-%sable text segment: %s", 3226 obj->path, before ? "en" : "dis", 3227 rtld_strerror(errno)); 3228 return (-1); 3229 } 3230 } 3231 return (0); 3232 } 3233 3234 /* Process RELR relative relocations. */ 3235 static void 3236 reloc_relr(Obj_Entry *obj) 3237 { 3238 const Elf_Relr *relr, *relrlim; 3239 Elf_Addr *where; 3240 3241 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3242 for (relr = obj->relr; relr < relrlim; relr++) { 3243 Elf_Relr entry = *relr; 3244 3245 if ((entry & 1) == 0) { 3246 where = (Elf_Addr *)(obj->relocbase + entry); 3247 *where++ += (Elf_Addr)obj->relocbase; 3248 } else { 3249 for (long i = 0; (entry >>= 1) != 0; i++) 3250 if ((entry & 1) != 0) 3251 where[i] += (Elf_Addr)obj->relocbase; 3252 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3253 } 3254 } 3255 } 3256 3257 /* 3258 * Relocate single object. 3259 * Returns 0 on success, or -1 on failure. 3260 */ 3261 static int 3262 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3263 int flags, RtldLockState *lockstate) 3264 { 3265 3266 if (obj->relocated) 3267 return (0); 3268 obj->relocated = true; 3269 if (obj != rtldobj) 3270 dbg("relocating \"%s\"", obj->path); 3271 3272 if (obj->symtab == NULL || obj->strtab == NULL || 3273 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3274 dbg("object %s has no run-time symbol table", obj->path); 3275 3276 /* There are relocations to the write-protected text segment. */ 3277 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3278 return (-1); 3279 3280 /* Process the non-PLT non-IFUNC relocations. */ 3281 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3282 return (-1); 3283 reloc_relr(obj); 3284 3285 /* Re-protected the text segment. */ 3286 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3287 return (-1); 3288 3289 /* Set the special PLT or GOT entries. */ 3290 init_pltgot(obj); 3291 3292 /* Process the PLT relocations. */ 3293 if (reloc_plt(obj, flags, lockstate) == -1) 3294 return (-1); 3295 /* Relocate the jump slots if we are doing immediate binding. */ 3296 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3297 lockstate) == -1) 3298 return (-1); 3299 3300 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3301 return (-1); 3302 3303 /* 3304 * Set up the magic number and version in the Obj_Entry. These 3305 * were checked in the crt1.o from the original ElfKit, so we 3306 * set them for backward compatibility. 3307 */ 3308 obj->magic = RTLD_MAGIC; 3309 obj->version = RTLD_VERSION; 3310 3311 return (0); 3312 } 3313 3314 /* 3315 * Relocate newly-loaded shared objects. The argument is a pointer to 3316 * the Obj_Entry for the first such object. All objects from the first 3317 * to the end of the list of objects are relocated. Returns 0 on success, 3318 * or -1 on failure. 3319 */ 3320 static int 3321 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3322 int flags, RtldLockState *lockstate) 3323 { 3324 Obj_Entry *obj; 3325 int error; 3326 3327 for (error = 0, obj = first; obj != NULL; 3328 obj = TAILQ_NEXT(obj, next)) { 3329 if (obj->marker) 3330 continue; 3331 error = relocate_object(obj, bind_now, rtldobj, flags, 3332 lockstate); 3333 if (error == -1) 3334 break; 3335 } 3336 return (error); 3337 } 3338 3339 /* 3340 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3341 * referencing STT_GNU_IFUNC symbols is postponed till the other 3342 * relocations are done. The indirect functions specified as 3343 * ifunc are allowed to call other symbols, so we need to have 3344 * objects relocated before asking for resolution from indirects. 3345 * 3346 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3347 * instead of the usual lazy handling of PLT slots. It is 3348 * consistent with how GNU does it. 3349 */ 3350 static int 3351 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3352 RtldLockState *lockstate) 3353 { 3354 3355 if (obj->ifuncs_resolved) 3356 return (0); 3357 obj->ifuncs_resolved = true; 3358 if (!obj->irelative && !obj->irelative_nonplt && 3359 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3360 !obj->non_plt_gnu_ifunc) 3361 return (0); 3362 if (obj_disable_relro(obj) == -1 || 3363 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3364 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3365 lockstate) == -1) || 3366 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3367 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3368 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3369 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3370 obj_enforce_relro(obj) == -1) 3371 return (-1); 3372 return (0); 3373 } 3374 3375 static int 3376 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3377 RtldLockState *lockstate) 3378 { 3379 Objlist_Entry *elm; 3380 Obj_Entry *obj; 3381 3382 STAILQ_FOREACH(elm, list, link) { 3383 obj = elm->obj; 3384 if (obj->marker) 3385 continue; 3386 if (resolve_object_ifunc(obj, bind_now, flags, 3387 lockstate) == -1) 3388 return (-1); 3389 } 3390 return (0); 3391 } 3392 3393 /* 3394 * Cleanup procedure. It will be called (by the atexit mechanism) just 3395 * before the process exits. 3396 */ 3397 static void 3398 rtld_exit(void) 3399 { 3400 RtldLockState lockstate; 3401 3402 wlock_acquire(rtld_bind_lock, &lockstate); 3403 dbg("rtld_exit()"); 3404 objlist_call_fini(&list_fini, NULL, &lockstate); 3405 /* No need to remove the items from the list, since we are exiting. */ 3406 if (!libmap_disable) 3407 lm_fini(); 3408 lock_release(rtld_bind_lock, &lockstate); 3409 } 3410 3411 static void 3412 rtld_nop_exit(void) 3413 { 3414 } 3415 3416 /* 3417 * Iterate over a search path, translate each element, and invoke the 3418 * callback on the result. 3419 */ 3420 static void * 3421 path_enumerate(const char *path, path_enum_proc callback, 3422 const char *refobj_path, void *arg) 3423 { 3424 const char *trans; 3425 if (path == NULL) 3426 return (NULL); 3427 3428 path += strspn(path, ":;"); 3429 while (*path != '\0') { 3430 size_t len; 3431 char *res; 3432 3433 len = strcspn(path, ":;"); 3434 trans = lm_findn(refobj_path, path, len); 3435 if (trans) 3436 res = callback(trans, strlen(trans), arg); 3437 else 3438 res = callback(path, len, arg); 3439 3440 if (res != NULL) 3441 return (res); 3442 3443 path += len; 3444 path += strspn(path, ":;"); 3445 } 3446 3447 return (NULL); 3448 } 3449 3450 struct try_library_args { 3451 const char *name; 3452 size_t namelen; 3453 char *buffer; 3454 size_t buflen; 3455 int fd; 3456 }; 3457 3458 static void * 3459 try_library_path(const char *dir, size_t dirlen, void *param) 3460 { 3461 struct try_library_args *arg; 3462 int fd; 3463 3464 arg = param; 3465 if (*dir == '/' || trust) { 3466 char *pathname; 3467 3468 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3469 return (NULL); 3470 3471 pathname = arg->buffer; 3472 strncpy(pathname, dir, dirlen); 3473 pathname[dirlen] = '/'; 3474 strcpy(pathname + dirlen + 1, arg->name); 3475 3476 dbg(" Trying \"%s\"", pathname); 3477 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3478 if (fd >= 0) { 3479 dbg(" Opened \"%s\", fd %d", pathname, fd); 3480 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3481 strcpy(pathname, arg->buffer); 3482 arg->fd = fd; 3483 return (pathname); 3484 } else { 3485 dbg(" Failed to open \"%s\": %s", 3486 pathname, rtld_strerror(errno)); 3487 } 3488 } 3489 return (NULL); 3490 } 3491 3492 static char * 3493 search_library_path(const char *name, const char *path, 3494 const char *refobj_path, int *fdp) 3495 { 3496 char *p; 3497 struct try_library_args arg; 3498 3499 if (path == NULL) 3500 return (NULL); 3501 3502 arg.name = name; 3503 arg.namelen = strlen(name); 3504 arg.buffer = xmalloc(PATH_MAX); 3505 arg.buflen = PATH_MAX; 3506 arg.fd = -1; 3507 3508 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3509 *fdp = arg.fd; 3510 3511 free(arg.buffer); 3512 3513 return (p); 3514 } 3515 3516 3517 /* 3518 * Finds the library with the given name using the directory descriptors 3519 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3520 * 3521 * Returns a freshly-opened close-on-exec file descriptor for the library, 3522 * or -1 if the library cannot be found. 3523 */ 3524 static char * 3525 search_library_pathfds(const char *name, const char *path, int *fdp) 3526 { 3527 char *envcopy, *fdstr, *found, *last_token; 3528 size_t len; 3529 int dirfd, fd; 3530 3531 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3532 3533 /* Don't load from user-specified libdirs into setuid binaries. */ 3534 if (!trust) 3535 return (NULL); 3536 3537 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3538 if (path == NULL) 3539 return (NULL); 3540 3541 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3542 if (name[0] == '/') { 3543 dbg("Absolute path (%s) passed to %s", name, __func__); 3544 return (NULL); 3545 } 3546 3547 /* 3548 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3549 * copy of the path, as strtok_r rewrites separator tokens 3550 * with '\0'. 3551 */ 3552 found = NULL; 3553 envcopy = xstrdup(path); 3554 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3555 fdstr = strtok_r(NULL, ":", &last_token)) { 3556 dirfd = parse_integer(fdstr); 3557 if (dirfd < 0) { 3558 _rtld_error("failed to parse directory FD: '%s'", 3559 fdstr); 3560 break; 3561 } 3562 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3563 if (fd >= 0) { 3564 *fdp = fd; 3565 len = strlen(fdstr) + strlen(name) + 3; 3566 found = xmalloc(len); 3567 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3568 _rtld_error("error generating '%d/%s'", 3569 dirfd, name); 3570 rtld_die(); 3571 } 3572 dbg("open('%s') => %d", found, fd); 3573 break; 3574 } 3575 } 3576 free(envcopy); 3577 3578 return (found); 3579 } 3580 3581 3582 int 3583 dlclose(void *handle) 3584 { 3585 RtldLockState lockstate; 3586 int error; 3587 3588 wlock_acquire(rtld_bind_lock, &lockstate); 3589 error = dlclose_locked(handle, &lockstate); 3590 lock_release(rtld_bind_lock, &lockstate); 3591 return (error); 3592 } 3593 3594 static int 3595 dlclose_locked(void *handle, RtldLockState *lockstate) 3596 { 3597 Obj_Entry *root; 3598 3599 root = dlcheck(handle); 3600 if (root == NULL) 3601 return (-1); 3602 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3603 root->path); 3604 3605 /* Unreference the object and its dependencies. */ 3606 root->dl_refcount--; 3607 3608 if (root->refcount == 1) { 3609 /* 3610 * The object will be no longer referenced, so we must unload it. 3611 * First, call the fini functions. 3612 */ 3613 objlist_call_fini(&list_fini, root, lockstate); 3614 3615 unref_dag(root); 3616 3617 /* Finish cleaning up the newly-unreferenced objects. */ 3618 GDB_STATE(RT_DELETE,&root->linkmap); 3619 unload_object(root, lockstate); 3620 GDB_STATE(RT_CONSISTENT,NULL); 3621 } else 3622 unref_dag(root); 3623 3624 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3625 return (0); 3626 } 3627 3628 char * 3629 dlerror(void) 3630 { 3631 if (*(lockinfo.dlerror_seen()) != 0) 3632 return (NULL); 3633 *lockinfo.dlerror_seen() = 1; 3634 return (lockinfo.dlerror_loc()); 3635 } 3636 3637 /* 3638 * This function is deprecated and has no effect. 3639 */ 3640 void 3641 dllockinit(void *context, 3642 void *(*_lock_create)(void *context) __unused, 3643 void (*_rlock_acquire)(void *lock) __unused, 3644 void (*_wlock_acquire)(void *lock) __unused, 3645 void (*_lock_release)(void *lock) __unused, 3646 void (*_lock_destroy)(void *lock) __unused, 3647 void (*context_destroy)(void *context)) 3648 { 3649 static void *cur_context; 3650 static void (*cur_context_destroy)(void *); 3651 3652 /* Just destroy the context from the previous call, if necessary. */ 3653 if (cur_context_destroy != NULL) 3654 cur_context_destroy(cur_context); 3655 cur_context = context; 3656 cur_context_destroy = context_destroy; 3657 } 3658 3659 void * 3660 dlopen(const char *name, int mode) 3661 { 3662 3663 return (rtld_dlopen(name, -1, mode)); 3664 } 3665 3666 void * 3667 fdlopen(int fd, int mode) 3668 { 3669 3670 return (rtld_dlopen(NULL, fd, mode)); 3671 } 3672 3673 static void * 3674 rtld_dlopen(const char *name, int fd, int mode) 3675 { 3676 RtldLockState lockstate; 3677 int lo_flags; 3678 3679 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3680 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3681 if (ld_tracing != NULL) { 3682 rlock_acquire(rtld_bind_lock, &lockstate); 3683 if (sigsetjmp(lockstate.env, 0) != 0) 3684 lock_upgrade(rtld_bind_lock, &lockstate); 3685 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3686 lock_release(rtld_bind_lock, &lockstate); 3687 } 3688 lo_flags = RTLD_LO_DLOPEN; 3689 if (mode & RTLD_NODELETE) 3690 lo_flags |= RTLD_LO_NODELETE; 3691 if (mode & RTLD_NOLOAD) 3692 lo_flags |= RTLD_LO_NOLOAD; 3693 if (mode & RTLD_DEEPBIND) 3694 lo_flags |= RTLD_LO_DEEPBIND; 3695 if (ld_tracing != NULL) 3696 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3697 3698 return (dlopen_object(name, fd, obj_main, lo_flags, 3699 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3700 } 3701 3702 static void 3703 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3704 { 3705 3706 obj->dl_refcount--; 3707 unref_dag(obj); 3708 if (obj->refcount == 0) 3709 unload_object(obj, lockstate); 3710 } 3711 3712 static Obj_Entry * 3713 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3714 int mode, RtldLockState *lockstate) 3715 { 3716 Obj_Entry *obj; 3717 Objlist initlist; 3718 RtldLockState mlockstate; 3719 int result; 3720 3721 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3722 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3723 refobj->path, lo_flags, mode); 3724 objlist_init(&initlist); 3725 3726 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3727 wlock_acquire(rtld_bind_lock, &mlockstate); 3728 lockstate = &mlockstate; 3729 } 3730 GDB_STATE(RT_ADD,NULL); 3731 3732 obj = NULL; 3733 if (name == NULL && fd == -1) { 3734 obj = obj_main; 3735 obj->refcount++; 3736 } else { 3737 obj = load_object(name, fd, refobj, lo_flags); 3738 } 3739 3740 if (obj) { 3741 obj->dl_refcount++; 3742 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3743 objlist_push_tail(&list_global, obj); 3744 3745 if (!obj->init_done) { 3746 /* We loaded something new and have to init something. */ 3747 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3748 obj->symbolic = true; 3749 result = 0; 3750 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3751 obj->static_tls && !allocate_tls_offset(obj)) { 3752 _rtld_error("%s: No space available " 3753 "for static Thread Local Storage", obj->path); 3754 result = -1; 3755 } 3756 if (result != -1) 3757 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3758 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3759 init_dag(obj); 3760 ref_dag(obj); 3761 if (result != -1) 3762 result = rtld_verify_versions(&obj->dagmembers); 3763 if (result != -1 && ld_tracing) 3764 goto trace; 3765 if (result == -1 || relocate_object_dag(obj, 3766 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3767 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3768 lockstate) == -1) { 3769 dlopen_cleanup(obj, lockstate); 3770 obj = NULL; 3771 } else if (lo_flags & RTLD_LO_EARLY) { 3772 /* 3773 * Do not call the init functions for early loaded 3774 * filtees. The image is still not initialized enough 3775 * for them to work. 3776 * 3777 * Our object is found by the global object list and 3778 * will be ordered among all init calls done right 3779 * before transferring control to main. 3780 */ 3781 } else { 3782 /* Make list of init functions to call. */ 3783 initlist_add_objects(obj, obj, &initlist); 3784 } 3785 /* 3786 * Process all no_delete or global objects here, given 3787 * them own DAGs to prevent their dependencies from being 3788 * unloaded. This has to be done after we have loaded all 3789 * of the dependencies, so that we do not miss any. 3790 */ 3791 if (obj != NULL) 3792 process_z(obj); 3793 } else { 3794 /* 3795 * Bump the reference counts for objects on this DAG. If 3796 * this is the first dlopen() call for the object that was 3797 * already loaded as a dependency, initialize the dag 3798 * starting at it. 3799 */ 3800 init_dag(obj); 3801 ref_dag(obj); 3802 3803 if ((lo_flags & RTLD_LO_TRACE) != 0) 3804 goto trace; 3805 } 3806 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3807 obj->z_nodelete) && !obj->ref_nodel) { 3808 dbg("obj %s nodelete", obj->path); 3809 ref_dag(obj); 3810 obj->z_nodelete = obj->ref_nodel = true; 3811 } 3812 } 3813 3814 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3815 name); 3816 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3817 3818 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3819 map_stacks_exec(lockstate); 3820 if (obj != NULL) 3821 distribute_static_tls(&initlist, lockstate); 3822 } 3823 3824 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3825 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3826 lockstate) == -1) { 3827 objlist_clear(&initlist); 3828 dlopen_cleanup(obj, lockstate); 3829 if (lockstate == &mlockstate) 3830 lock_release(rtld_bind_lock, lockstate); 3831 return (NULL); 3832 } 3833 3834 if (!(lo_flags & RTLD_LO_EARLY)) { 3835 /* Call the init functions. */ 3836 objlist_call_init(&initlist, lockstate); 3837 } 3838 objlist_clear(&initlist); 3839 if (lockstate == &mlockstate) 3840 lock_release(rtld_bind_lock, lockstate); 3841 return (obj); 3842 trace: 3843 trace_loaded_objects(obj, false); 3844 if (lockstate == &mlockstate) 3845 lock_release(rtld_bind_lock, lockstate); 3846 exit(0); 3847 } 3848 3849 static void * 3850 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3851 int flags) 3852 { 3853 DoneList donelist; 3854 const Obj_Entry *obj, *defobj; 3855 const Elf_Sym *def; 3856 SymLook req; 3857 RtldLockState lockstate; 3858 tls_index ti; 3859 void *sym; 3860 int res; 3861 3862 def = NULL; 3863 defobj = NULL; 3864 symlook_init(&req, name); 3865 req.ventry = ve; 3866 req.flags = flags | SYMLOOK_IN_PLT; 3867 req.lockstate = &lockstate; 3868 3869 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3870 rlock_acquire(rtld_bind_lock, &lockstate); 3871 if (sigsetjmp(lockstate.env, 0) != 0) 3872 lock_upgrade(rtld_bind_lock, &lockstate); 3873 if (handle == NULL || handle == RTLD_NEXT || 3874 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3875 3876 if ((obj = obj_from_addr(retaddr)) == NULL) { 3877 _rtld_error("Cannot determine caller's shared object"); 3878 lock_release(rtld_bind_lock, &lockstate); 3879 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3880 return (NULL); 3881 } 3882 if (handle == NULL) { /* Just the caller's shared object. */ 3883 res = symlook_obj(&req, obj); 3884 if (res == 0) { 3885 def = req.sym_out; 3886 defobj = req.defobj_out; 3887 } 3888 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3889 handle == RTLD_SELF) { /* ... caller included */ 3890 if (handle == RTLD_NEXT) 3891 obj = globallist_next(obj); 3892 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3893 if (obj->marker) 3894 continue; 3895 res = symlook_obj(&req, obj); 3896 if (res == 0) { 3897 if (def == NULL || (ld_dynamic_weak && 3898 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3899 def = req.sym_out; 3900 defobj = req.defobj_out; 3901 if (!ld_dynamic_weak || 3902 ELF_ST_BIND(def->st_info) != STB_WEAK) 3903 break; 3904 } 3905 } 3906 } 3907 /* 3908 * Search the dynamic linker itself, and possibly resolve the 3909 * symbol from there. This is how the application links to 3910 * dynamic linker services such as dlopen. 3911 * Note that we ignore ld_dynamic_weak == false case, 3912 * always overriding weak symbols by rtld definitions. 3913 */ 3914 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3915 res = symlook_obj(&req, &obj_rtld); 3916 if (res == 0) { 3917 def = req.sym_out; 3918 defobj = req.defobj_out; 3919 } 3920 } 3921 } else { 3922 assert(handle == RTLD_DEFAULT); 3923 res = symlook_default(&req, obj); 3924 if (res == 0) { 3925 defobj = req.defobj_out; 3926 def = req.sym_out; 3927 } 3928 } 3929 } else { 3930 if ((obj = dlcheck(handle)) == NULL) { 3931 lock_release(rtld_bind_lock, &lockstate); 3932 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3933 return (NULL); 3934 } 3935 3936 donelist_init(&donelist); 3937 if (obj->mainprog) { 3938 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3939 res = symlook_global(&req, &donelist); 3940 if (res == 0) { 3941 def = req.sym_out; 3942 defobj = req.defobj_out; 3943 } 3944 /* 3945 * Search the dynamic linker itself, and possibly resolve the 3946 * symbol from there. This is how the application links to 3947 * dynamic linker services such as dlopen. 3948 */ 3949 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3950 res = symlook_obj(&req, &obj_rtld); 3951 if (res == 0) { 3952 def = req.sym_out; 3953 defobj = req.defobj_out; 3954 } 3955 } 3956 } 3957 else { 3958 /* Search the whole DAG rooted at the given object. */ 3959 res = symlook_list(&req, &obj->dagmembers, &donelist); 3960 if (res == 0) { 3961 def = req.sym_out; 3962 defobj = req.defobj_out; 3963 } 3964 } 3965 } 3966 3967 if (def != NULL) { 3968 lock_release(rtld_bind_lock, &lockstate); 3969 3970 /* 3971 * The value required by the caller is derived from the value 3972 * of the symbol. this is simply the relocated value of the 3973 * symbol. 3974 */ 3975 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3976 sym = make_function_pointer(def, defobj); 3977 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3978 sym = rtld_resolve_ifunc(defobj, def); 3979 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3980 ti.ti_module = defobj->tlsindex; 3981 ti.ti_offset = def->st_value; 3982 sym = __tls_get_addr(&ti); 3983 } else 3984 sym = defobj->relocbase + def->st_value; 3985 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3986 return (sym); 3987 } 3988 3989 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3990 ve != NULL ? ve->name : ""); 3991 lock_release(rtld_bind_lock, &lockstate); 3992 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3993 return (NULL); 3994 } 3995 3996 void * 3997 dlsym(void *handle, const char *name) 3998 { 3999 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4000 SYMLOOK_DLSYM)); 4001 } 4002 4003 dlfunc_t 4004 dlfunc(void *handle, const char *name) 4005 { 4006 union { 4007 void *d; 4008 dlfunc_t f; 4009 } rv; 4010 4011 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4012 SYMLOOK_DLSYM); 4013 return (rv.f); 4014 } 4015 4016 void * 4017 dlvsym(void *handle, const char *name, const char *version) 4018 { 4019 Ver_Entry ventry; 4020 4021 ventry.name = version; 4022 ventry.file = NULL; 4023 ventry.hash = elf_hash(version); 4024 ventry.flags= 0; 4025 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4026 SYMLOOK_DLSYM)); 4027 } 4028 4029 int 4030 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4031 { 4032 const Obj_Entry *obj; 4033 RtldLockState lockstate; 4034 4035 rlock_acquire(rtld_bind_lock, &lockstate); 4036 obj = obj_from_addr(addr); 4037 if (obj == NULL) { 4038 _rtld_error("No shared object contains address"); 4039 lock_release(rtld_bind_lock, &lockstate); 4040 return (0); 4041 } 4042 rtld_fill_dl_phdr_info(obj, phdr_info); 4043 lock_release(rtld_bind_lock, &lockstate); 4044 return (1); 4045 } 4046 4047 int 4048 dladdr(const void *addr, Dl_info *info) 4049 { 4050 const Obj_Entry *obj; 4051 const Elf_Sym *def; 4052 void *symbol_addr; 4053 unsigned long symoffset; 4054 RtldLockState lockstate; 4055 4056 rlock_acquire(rtld_bind_lock, &lockstate); 4057 obj = obj_from_addr(addr); 4058 if (obj == NULL) { 4059 _rtld_error("No shared object contains address"); 4060 lock_release(rtld_bind_lock, &lockstate); 4061 return (0); 4062 } 4063 info->dli_fname = obj->path; 4064 info->dli_fbase = obj->mapbase; 4065 info->dli_saddr = (void *)0; 4066 info->dli_sname = NULL; 4067 4068 /* 4069 * Walk the symbol list looking for the symbol whose address is 4070 * closest to the address sent in. 4071 */ 4072 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4073 def = obj->symtab + symoffset; 4074 4075 /* 4076 * For skip the symbol if st_shndx is either SHN_UNDEF or 4077 * SHN_COMMON. 4078 */ 4079 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4080 continue; 4081 4082 /* 4083 * If the symbol is greater than the specified address, or if it 4084 * is further away from addr than the current nearest symbol, 4085 * then reject it. 4086 */ 4087 symbol_addr = obj->relocbase + def->st_value; 4088 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4089 continue; 4090 4091 /* Update our idea of the nearest symbol. */ 4092 info->dli_sname = obj->strtab + def->st_name; 4093 info->dli_saddr = symbol_addr; 4094 4095 /* Exact match? */ 4096 if (info->dli_saddr == addr) 4097 break; 4098 } 4099 lock_release(rtld_bind_lock, &lockstate); 4100 return (1); 4101 } 4102 4103 int 4104 dlinfo(void *handle, int request, void *p) 4105 { 4106 const Obj_Entry *obj; 4107 RtldLockState lockstate; 4108 int error; 4109 4110 rlock_acquire(rtld_bind_lock, &lockstate); 4111 4112 if (handle == NULL || handle == RTLD_SELF) { 4113 void *retaddr; 4114 4115 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4116 if ((obj = obj_from_addr(retaddr)) == NULL) 4117 _rtld_error("Cannot determine caller's shared object"); 4118 } else 4119 obj = dlcheck(handle); 4120 4121 if (obj == NULL) { 4122 lock_release(rtld_bind_lock, &lockstate); 4123 return (-1); 4124 } 4125 4126 error = 0; 4127 switch (request) { 4128 case RTLD_DI_LINKMAP: 4129 *((struct link_map const **)p) = &obj->linkmap; 4130 break; 4131 case RTLD_DI_ORIGIN: 4132 error = rtld_dirname(obj->path, p); 4133 break; 4134 4135 case RTLD_DI_SERINFOSIZE: 4136 case RTLD_DI_SERINFO: 4137 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4138 break; 4139 4140 default: 4141 _rtld_error("Invalid request %d passed to dlinfo()", request); 4142 error = -1; 4143 } 4144 4145 lock_release(rtld_bind_lock, &lockstate); 4146 4147 return (error); 4148 } 4149 4150 static void 4151 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4152 { 4153 uintptr_t **dtvp; 4154 4155 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4156 phdr_info->dlpi_name = obj->path; 4157 phdr_info->dlpi_phdr = obj->phdr; 4158 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4159 phdr_info->dlpi_tls_modid = obj->tlsindex; 4160 dtvp = &_tcb_get()->tcb_dtv; 4161 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4162 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4163 phdr_info->dlpi_adds = obj_loads; 4164 phdr_info->dlpi_subs = obj_loads - obj_count; 4165 } 4166 4167 int 4168 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4169 { 4170 struct dl_phdr_info phdr_info; 4171 Obj_Entry *obj, marker; 4172 RtldLockState bind_lockstate, phdr_lockstate; 4173 int error; 4174 4175 init_marker(&marker); 4176 error = 0; 4177 4178 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4179 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4180 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4181 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4182 rtld_fill_dl_phdr_info(obj, &phdr_info); 4183 hold_object(obj); 4184 lock_release(rtld_bind_lock, &bind_lockstate); 4185 4186 error = callback(&phdr_info, sizeof phdr_info, param); 4187 4188 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4189 unhold_object(obj); 4190 obj = globallist_next(&marker); 4191 TAILQ_REMOVE(&obj_list, &marker, next); 4192 if (error != 0) { 4193 lock_release(rtld_bind_lock, &bind_lockstate); 4194 lock_release(rtld_phdr_lock, &phdr_lockstate); 4195 return (error); 4196 } 4197 } 4198 4199 if (error == 0) { 4200 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4201 lock_release(rtld_bind_lock, &bind_lockstate); 4202 error = callback(&phdr_info, sizeof(phdr_info), param); 4203 } 4204 lock_release(rtld_phdr_lock, &phdr_lockstate); 4205 return (error); 4206 } 4207 4208 static void * 4209 fill_search_info(const char *dir, size_t dirlen, void *param) 4210 { 4211 struct fill_search_info_args *arg; 4212 4213 arg = param; 4214 4215 if (arg->request == RTLD_DI_SERINFOSIZE) { 4216 arg->serinfo->dls_cnt ++; 4217 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4218 } else { 4219 struct dl_serpath *s_entry; 4220 4221 s_entry = arg->serpath; 4222 s_entry->dls_name = arg->strspace; 4223 s_entry->dls_flags = arg->flags; 4224 4225 strncpy(arg->strspace, dir, dirlen); 4226 arg->strspace[dirlen] = '\0'; 4227 4228 arg->strspace += dirlen + 1; 4229 arg->serpath++; 4230 } 4231 4232 return (NULL); 4233 } 4234 4235 static int 4236 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4237 { 4238 struct dl_serinfo _info; 4239 struct fill_search_info_args args; 4240 4241 args.request = RTLD_DI_SERINFOSIZE; 4242 args.serinfo = &_info; 4243 4244 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4245 _info.dls_cnt = 0; 4246 4247 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4248 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4249 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4250 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4251 if (!obj->z_nodeflib) 4252 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4253 4254 4255 if (request == RTLD_DI_SERINFOSIZE) { 4256 info->dls_size = _info.dls_size; 4257 info->dls_cnt = _info.dls_cnt; 4258 return (0); 4259 } 4260 4261 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4262 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4263 return (-1); 4264 } 4265 4266 args.request = RTLD_DI_SERINFO; 4267 args.serinfo = info; 4268 args.serpath = &info->dls_serpath[0]; 4269 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4270 4271 args.flags = LA_SER_RUNPATH; 4272 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4273 return (-1); 4274 4275 args.flags = LA_SER_LIBPATH; 4276 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4277 return (-1); 4278 4279 args.flags = LA_SER_RUNPATH; 4280 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4281 return (-1); 4282 4283 args.flags = LA_SER_CONFIG; 4284 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4285 != NULL) 4286 return (-1); 4287 4288 args.flags = LA_SER_DEFAULT; 4289 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4290 fill_search_info, NULL, &args) != NULL) 4291 return (-1); 4292 return (0); 4293 } 4294 4295 static int 4296 rtld_dirname(const char *path, char *bname) 4297 { 4298 const char *endp; 4299 4300 /* Empty or NULL string gets treated as "." */ 4301 if (path == NULL || *path == '\0') { 4302 bname[0] = '.'; 4303 bname[1] = '\0'; 4304 return (0); 4305 } 4306 4307 /* Strip trailing slashes */ 4308 endp = path + strlen(path) - 1; 4309 while (endp > path && *endp == '/') 4310 endp--; 4311 4312 /* Find the start of the dir */ 4313 while (endp > path && *endp != '/') 4314 endp--; 4315 4316 /* Either the dir is "/" or there are no slashes */ 4317 if (endp == path) { 4318 bname[0] = *endp == '/' ? '/' : '.'; 4319 bname[1] = '\0'; 4320 return (0); 4321 } else { 4322 do { 4323 endp--; 4324 } while (endp > path && *endp == '/'); 4325 } 4326 4327 if (endp - path + 2 > PATH_MAX) 4328 { 4329 _rtld_error("Filename is too long: %s", path); 4330 return(-1); 4331 } 4332 4333 strncpy(bname, path, endp - path + 1); 4334 bname[endp - path + 1] = '\0'; 4335 return (0); 4336 } 4337 4338 static int 4339 rtld_dirname_abs(const char *path, char *base) 4340 { 4341 char *last; 4342 4343 if (realpath(path, base) == NULL) { 4344 _rtld_error("realpath \"%s\" failed (%s)", path, 4345 rtld_strerror(errno)); 4346 return (-1); 4347 } 4348 dbg("%s -> %s", path, base); 4349 last = strrchr(base, '/'); 4350 if (last == NULL) { 4351 _rtld_error("non-abs result from realpath \"%s\"", path); 4352 return (-1); 4353 } 4354 if (last != base) 4355 *last = '\0'; 4356 return (0); 4357 } 4358 4359 static void 4360 linkmap_add(Obj_Entry *obj) 4361 { 4362 struct link_map *l, *prev; 4363 4364 l = &obj->linkmap; 4365 l->l_name = obj->path; 4366 l->l_base = obj->mapbase; 4367 l->l_ld = obj->dynamic; 4368 l->l_addr = obj->relocbase; 4369 4370 if (r_debug.r_map == NULL) { 4371 r_debug.r_map = l; 4372 return; 4373 } 4374 4375 /* 4376 * Scan to the end of the list, but not past the entry for the 4377 * dynamic linker, which we want to keep at the very end. 4378 */ 4379 for (prev = r_debug.r_map; 4380 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4381 prev = prev->l_next) 4382 ; 4383 4384 /* Link in the new entry. */ 4385 l->l_prev = prev; 4386 l->l_next = prev->l_next; 4387 if (l->l_next != NULL) 4388 l->l_next->l_prev = l; 4389 prev->l_next = l; 4390 } 4391 4392 static void 4393 linkmap_delete(Obj_Entry *obj) 4394 { 4395 struct link_map *l; 4396 4397 l = &obj->linkmap; 4398 if (l->l_prev == NULL) { 4399 if ((r_debug.r_map = l->l_next) != NULL) 4400 l->l_next->l_prev = NULL; 4401 return; 4402 } 4403 4404 if ((l->l_prev->l_next = l->l_next) != NULL) 4405 l->l_next->l_prev = l->l_prev; 4406 } 4407 4408 /* 4409 * Function for the debugger to set a breakpoint on to gain control. 4410 * 4411 * The two parameters allow the debugger to easily find and determine 4412 * what the runtime loader is doing and to whom it is doing it. 4413 * 4414 * When the loadhook trap is hit (r_debug_state, set at program 4415 * initialization), the arguments can be found on the stack: 4416 * 4417 * +8 struct link_map *m 4418 * +4 struct r_debug *rd 4419 * +0 RetAddr 4420 */ 4421 void 4422 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4423 { 4424 /* 4425 * The following is a hack to force the compiler to emit calls to 4426 * this function, even when optimizing. If the function is empty, 4427 * the compiler is not obliged to emit any code for calls to it, 4428 * even when marked __noinline. However, gdb depends on those 4429 * calls being made. 4430 */ 4431 __compiler_membar(); 4432 } 4433 4434 /* 4435 * A function called after init routines have completed. This can be used to 4436 * break before a program's entry routine is called, and can be used when 4437 * main is not available in the symbol table. 4438 */ 4439 void 4440 _r_debug_postinit(struct link_map *m __unused) 4441 { 4442 4443 /* See r_debug_state(). */ 4444 __compiler_membar(); 4445 } 4446 4447 static void 4448 release_object(Obj_Entry *obj) 4449 { 4450 4451 if (obj->holdcount > 0) { 4452 obj->unholdfree = true; 4453 return; 4454 } 4455 munmap(obj->mapbase, obj->mapsize); 4456 linkmap_delete(obj); 4457 obj_free(obj); 4458 } 4459 4460 /* 4461 * Get address of the pointer variable in the main program. 4462 * Prefer non-weak symbol over the weak one. 4463 */ 4464 static const void ** 4465 get_program_var_addr(const char *name, RtldLockState *lockstate) 4466 { 4467 SymLook req; 4468 DoneList donelist; 4469 4470 symlook_init(&req, name); 4471 req.lockstate = lockstate; 4472 donelist_init(&donelist); 4473 if (symlook_global(&req, &donelist) != 0) 4474 return (NULL); 4475 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4476 return ((const void **)make_function_pointer(req.sym_out, 4477 req.defobj_out)); 4478 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4479 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4480 else 4481 return ((const void **)(req.defobj_out->relocbase + 4482 req.sym_out->st_value)); 4483 } 4484 4485 /* 4486 * Set a pointer variable in the main program to the given value. This 4487 * is used to set key variables such as "environ" before any of the 4488 * init functions are called. 4489 */ 4490 static void 4491 set_program_var(const char *name, const void *value) 4492 { 4493 const void **addr; 4494 4495 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4496 dbg("\"%s\": *%p <-- %p", name, addr, value); 4497 *addr = value; 4498 } 4499 } 4500 4501 /* 4502 * Search the global objects, including dependencies and main object, 4503 * for the given symbol. 4504 */ 4505 static int 4506 symlook_global(SymLook *req, DoneList *donelist) 4507 { 4508 SymLook req1; 4509 const Objlist_Entry *elm; 4510 int res; 4511 4512 symlook_init_from_req(&req1, req); 4513 4514 /* Search all objects loaded at program start up. */ 4515 if (req->defobj_out == NULL || (ld_dynamic_weak && 4516 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4517 res = symlook_list(&req1, &list_main, donelist); 4518 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4519 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4520 req->sym_out = req1.sym_out; 4521 req->defobj_out = req1.defobj_out; 4522 assert(req->defobj_out != NULL); 4523 } 4524 } 4525 4526 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4527 STAILQ_FOREACH(elm, &list_global, link) { 4528 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4529 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4530 break; 4531 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4532 if (res == 0 && (req->defobj_out == NULL || 4533 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4534 req->sym_out = req1.sym_out; 4535 req->defobj_out = req1.defobj_out; 4536 assert(req->defobj_out != NULL); 4537 } 4538 } 4539 4540 return (req->sym_out != NULL ? 0 : ESRCH); 4541 } 4542 4543 /* 4544 * Given a symbol name in a referencing object, find the corresponding 4545 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4546 * no definition was found. Returns a pointer to the Obj_Entry of the 4547 * defining object via the reference parameter DEFOBJ_OUT. 4548 */ 4549 static int 4550 symlook_default(SymLook *req, const Obj_Entry *refobj) 4551 { 4552 DoneList donelist; 4553 const Objlist_Entry *elm; 4554 SymLook req1; 4555 int res; 4556 4557 donelist_init(&donelist); 4558 symlook_init_from_req(&req1, req); 4559 4560 /* 4561 * Look first in the referencing object if linked symbolically, 4562 * and similarly handle protected symbols. 4563 */ 4564 res = symlook_obj(&req1, refobj); 4565 if (res == 0 && (refobj->symbolic || 4566 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4567 req->sym_out = req1.sym_out; 4568 req->defobj_out = req1.defobj_out; 4569 assert(req->defobj_out != NULL); 4570 } 4571 if (refobj->symbolic || req->defobj_out != NULL) 4572 donelist_check(&donelist, refobj); 4573 4574 symlook_global(req, &donelist); 4575 4576 /* Search all dlopened DAGs containing the referencing object. */ 4577 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4578 if (req->sym_out != NULL && (!ld_dynamic_weak || 4579 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4580 break; 4581 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4582 if (res == 0 && (req->sym_out == NULL || 4583 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4584 req->sym_out = req1.sym_out; 4585 req->defobj_out = req1.defobj_out; 4586 assert(req->defobj_out != NULL); 4587 } 4588 } 4589 4590 /* 4591 * Search the dynamic linker itself, and possibly resolve the 4592 * symbol from there. This is how the application links to 4593 * dynamic linker services such as dlopen. 4594 */ 4595 if (req->sym_out == NULL || 4596 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4597 res = symlook_obj(&req1, &obj_rtld); 4598 if (res == 0) { 4599 req->sym_out = req1.sym_out; 4600 req->defobj_out = req1.defobj_out; 4601 assert(req->defobj_out != NULL); 4602 } 4603 } 4604 4605 return (req->sym_out != NULL ? 0 : ESRCH); 4606 } 4607 4608 static int 4609 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4610 { 4611 const Elf_Sym *def; 4612 const Obj_Entry *defobj; 4613 const Objlist_Entry *elm; 4614 SymLook req1; 4615 int res; 4616 4617 def = NULL; 4618 defobj = NULL; 4619 STAILQ_FOREACH(elm, objlist, link) { 4620 if (donelist_check(dlp, elm->obj)) 4621 continue; 4622 symlook_init_from_req(&req1, req); 4623 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4624 if (def == NULL || (ld_dynamic_weak && 4625 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4626 def = req1.sym_out; 4627 defobj = req1.defobj_out; 4628 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4629 break; 4630 } 4631 } 4632 } 4633 if (def != NULL) { 4634 req->sym_out = def; 4635 req->defobj_out = defobj; 4636 return (0); 4637 } 4638 return (ESRCH); 4639 } 4640 4641 /* 4642 * Search the chain of DAGS cointed to by the given Needed_Entry 4643 * for a symbol of the given name. Each DAG is scanned completely 4644 * before advancing to the next one. Returns a pointer to the symbol, 4645 * or NULL if no definition was found. 4646 */ 4647 static int 4648 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4649 { 4650 const Elf_Sym *def; 4651 const Needed_Entry *n; 4652 const Obj_Entry *defobj; 4653 SymLook req1; 4654 int res; 4655 4656 def = NULL; 4657 defobj = NULL; 4658 symlook_init_from_req(&req1, req); 4659 for (n = needed; n != NULL; n = n->next) { 4660 if (n->obj == NULL || 4661 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4662 continue; 4663 if (def == NULL || (ld_dynamic_weak && 4664 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4665 def = req1.sym_out; 4666 defobj = req1.defobj_out; 4667 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4668 break; 4669 } 4670 } 4671 if (def != NULL) { 4672 req->sym_out = def; 4673 req->defobj_out = defobj; 4674 return (0); 4675 } 4676 return (ESRCH); 4677 } 4678 4679 /* 4680 * Search the symbol table of a single shared object for a symbol of 4681 * the given name and version, if requested. Returns a pointer to the 4682 * symbol, or NULL if no definition was found. If the object is 4683 * filter, return filtered symbol from filtee. 4684 * 4685 * The symbol's hash value is passed in for efficiency reasons; that 4686 * eliminates many recomputations of the hash value. 4687 */ 4688 int 4689 symlook_obj(SymLook *req, const Obj_Entry *obj) 4690 { 4691 DoneList donelist; 4692 SymLook req1; 4693 int flags, res, mres; 4694 4695 /* 4696 * If there is at least one valid hash at this point, we prefer to 4697 * use the faster GNU version if available. 4698 */ 4699 if (obj->valid_hash_gnu) 4700 mres = symlook_obj1_gnu(req, obj); 4701 else if (obj->valid_hash_sysv) 4702 mres = symlook_obj1_sysv(req, obj); 4703 else 4704 return (EINVAL); 4705 4706 if (mres == 0) { 4707 if (obj->needed_filtees != NULL) { 4708 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4709 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4710 donelist_init(&donelist); 4711 symlook_init_from_req(&req1, req); 4712 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4713 if (res == 0) { 4714 req->sym_out = req1.sym_out; 4715 req->defobj_out = req1.defobj_out; 4716 } 4717 return (res); 4718 } 4719 if (obj->needed_aux_filtees != NULL) { 4720 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4721 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4722 donelist_init(&donelist); 4723 symlook_init_from_req(&req1, req); 4724 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4725 if (res == 0) { 4726 req->sym_out = req1.sym_out; 4727 req->defobj_out = req1.defobj_out; 4728 return (res); 4729 } 4730 } 4731 } 4732 return (mres); 4733 } 4734 4735 /* Symbol match routine common to both hash functions */ 4736 static bool 4737 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4738 const unsigned long symnum) 4739 { 4740 Elf_Versym verndx; 4741 const Elf_Sym *symp; 4742 const char *strp; 4743 4744 symp = obj->symtab + symnum; 4745 strp = obj->strtab + symp->st_name; 4746 4747 switch (ELF_ST_TYPE(symp->st_info)) { 4748 case STT_FUNC: 4749 case STT_NOTYPE: 4750 case STT_OBJECT: 4751 case STT_COMMON: 4752 case STT_GNU_IFUNC: 4753 if (symp->st_value == 0) 4754 return (false); 4755 /* fallthrough */ 4756 case STT_TLS: 4757 if (symp->st_shndx != SHN_UNDEF) 4758 break; 4759 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4760 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4761 break; 4762 /* fallthrough */ 4763 default: 4764 return (false); 4765 } 4766 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4767 return (false); 4768 4769 if (req->ventry == NULL) { 4770 if (obj->versyms != NULL) { 4771 verndx = VER_NDX(obj->versyms[symnum]); 4772 if (verndx > obj->vernum) { 4773 _rtld_error( 4774 "%s: symbol %s references wrong version %d", 4775 obj->path, obj->strtab + symnum, verndx); 4776 return (false); 4777 } 4778 /* 4779 * If we are not called from dlsym (i.e. this 4780 * is a normal relocation from unversioned 4781 * binary), accept the symbol immediately if 4782 * it happens to have first version after this 4783 * shared object became versioned. Otherwise, 4784 * if symbol is versioned and not hidden, 4785 * remember it. If it is the only symbol with 4786 * this name exported by the shared object, it 4787 * will be returned as a match by the calling 4788 * function. If symbol is global (verndx < 2) 4789 * accept it unconditionally. 4790 */ 4791 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4792 verndx == VER_NDX_GIVEN) { 4793 result->sym_out = symp; 4794 return (true); 4795 } 4796 else if (verndx >= VER_NDX_GIVEN) { 4797 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4798 == 0) { 4799 if (result->vsymp == NULL) 4800 result->vsymp = symp; 4801 result->vcount++; 4802 } 4803 return (false); 4804 } 4805 } 4806 result->sym_out = symp; 4807 return (true); 4808 } 4809 if (obj->versyms == NULL) { 4810 if (object_match_name(obj, req->ventry->name)) { 4811 _rtld_error("%s: object %s should provide version %s " 4812 "for symbol %s", obj_rtld.path, obj->path, 4813 req->ventry->name, obj->strtab + symnum); 4814 return (false); 4815 } 4816 } else { 4817 verndx = VER_NDX(obj->versyms[symnum]); 4818 if (verndx > obj->vernum) { 4819 _rtld_error("%s: symbol %s references wrong version %d", 4820 obj->path, obj->strtab + symnum, verndx); 4821 return (false); 4822 } 4823 if (obj->vertab[verndx].hash != req->ventry->hash || 4824 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4825 /* 4826 * Version does not match. Look if this is a 4827 * global symbol and if it is not hidden. If 4828 * global symbol (verndx < 2) is available, 4829 * use it. Do not return symbol if we are 4830 * called by dlvsym, because dlvsym looks for 4831 * a specific version and default one is not 4832 * what dlvsym wants. 4833 */ 4834 if ((req->flags & SYMLOOK_DLSYM) || 4835 (verndx >= VER_NDX_GIVEN) || 4836 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4837 return (false); 4838 } 4839 } 4840 result->sym_out = symp; 4841 return (true); 4842 } 4843 4844 /* 4845 * Search for symbol using SysV hash function. 4846 * obj->buckets is known not to be NULL at this point; the test for this was 4847 * performed with the obj->valid_hash_sysv assignment. 4848 */ 4849 static int 4850 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4851 { 4852 unsigned long symnum; 4853 Sym_Match_Result matchres; 4854 4855 matchres.sym_out = NULL; 4856 matchres.vsymp = NULL; 4857 matchres.vcount = 0; 4858 4859 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4860 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4861 if (symnum >= obj->nchains) 4862 return (ESRCH); /* Bad object */ 4863 4864 if (matched_symbol(req, obj, &matchres, symnum)) { 4865 req->sym_out = matchres.sym_out; 4866 req->defobj_out = obj; 4867 return (0); 4868 } 4869 } 4870 if (matchres.vcount == 1) { 4871 req->sym_out = matchres.vsymp; 4872 req->defobj_out = obj; 4873 return (0); 4874 } 4875 return (ESRCH); 4876 } 4877 4878 /* Search for symbol using GNU hash function */ 4879 static int 4880 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4881 { 4882 Elf_Addr bloom_word; 4883 const Elf32_Word *hashval; 4884 Elf32_Word bucket; 4885 Sym_Match_Result matchres; 4886 unsigned int h1, h2; 4887 unsigned long symnum; 4888 4889 matchres.sym_out = NULL; 4890 matchres.vsymp = NULL; 4891 matchres.vcount = 0; 4892 4893 /* Pick right bitmask word from Bloom filter array */ 4894 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4895 obj->maskwords_bm_gnu]; 4896 4897 /* Calculate modulus word size of gnu hash and its derivative */ 4898 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4899 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4900 4901 /* Filter out the "definitely not in set" queries */ 4902 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4903 return (ESRCH); 4904 4905 /* Locate hash chain and corresponding value element*/ 4906 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4907 if (bucket == 0) 4908 return (ESRCH); 4909 hashval = &obj->chain_zero_gnu[bucket]; 4910 do { 4911 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4912 symnum = hashval - obj->chain_zero_gnu; 4913 if (matched_symbol(req, obj, &matchres, symnum)) { 4914 req->sym_out = matchres.sym_out; 4915 req->defobj_out = obj; 4916 return (0); 4917 } 4918 } 4919 } while ((*hashval++ & 1) == 0); 4920 if (matchres.vcount == 1) { 4921 req->sym_out = matchres.vsymp; 4922 req->defobj_out = obj; 4923 return (0); 4924 } 4925 return (ESRCH); 4926 } 4927 4928 static void 4929 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4930 { 4931 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4932 if (*main_local == NULL) 4933 *main_local = ""; 4934 4935 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4936 if (*fmt1 == NULL) 4937 *fmt1 = "\t%o => %p (%x)\n"; 4938 4939 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4940 if (*fmt2 == NULL) 4941 *fmt2 = "\t%o (%x)\n"; 4942 } 4943 4944 static void 4945 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4946 const char *main_local, const char *fmt1, const char *fmt2) 4947 { 4948 const char *fmt; 4949 int c; 4950 4951 if (fmt1 == NULL) 4952 fmt = fmt2; 4953 else 4954 /* XXX bogus */ 4955 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 4956 4957 while ((c = *fmt++) != '\0') { 4958 switch (c) { 4959 default: 4960 rtld_putchar(c); 4961 continue; 4962 case '\\': 4963 switch (c = *fmt) { 4964 case '\0': 4965 continue; 4966 case 'n': 4967 rtld_putchar('\n'); 4968 break; 4969 case 't': 4970 rtld_putchar('\t'); 4971 break; 4972 } 4973 break; 4974 case '%': 4975 switch (c = *fmt) { 4976 case '\0': 4977 continue; 4978 case '%': 4979 default: 4980 rtld_putchar(c); 4981 break; 4982 case 'A': 4983 rtld_putstr(main_local); 4984 break; 4985 case 'a': 4986 rtld_putstr(obj_main->path); 4987 break; 4988 case 'o': 4989 rtld_putstr(name); 4990 break; 4991 case 'p': 4992 rtld_putstr(path); 4993 break; 4994 case 'x': 4995 rtld_printf("%p", obj != NULL ? 4996 obj->mapbase : NULL); 4997 break; 4998 } 4999 break; 5000 } 5001 ++fmt; 5002 } 5003 } 5004 5005 static void 5006 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5007 { 5008 const char *fmt1, *fmt2, *main_local; 5009 const char *name, *path; 5010 bool first_spurious, list_containers; 5011 5012 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5013 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5014 5015 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5016 Needed_Entry *needed; 5017 5018 if (obj->marker) 5019 continue; 5020 if (list_containers && obj->needed != NULL) 5021 rtld_printf("%s:\n", obj->path); 5022 for (needed = obj->needed; needed; needed = needed->next) { 5023 if (needed->obj != NULL) { 5024 if (needed->obj->traced && !list_containers) 5025 continue; 5026 needed->obj->traced = true; 5027 path = needed->obj->path; 5028 } else 5029 path = "not found"; 5030 5031 name = obj->strtab + needed->name; 5032 trace_print_obj(needed->obj, name, path, main_local, 5033 fmt1, fmt2); 5034 } 5035 } 5036 5037 if (show_preload) { 5038 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5039 fmt2 = "\t%p (%x)\n"; 5040 first_spurious = true; 5041 5042 TAILQ_FOREACH(obj, &obj_list, next) { 5043 if (obj->marker || obj == obj_main || obj->traced) 5044 continue; 5045 5046 if (list_containers && first_spurious) { 5047 rtld_printf("[preloaded]\n"); 5048 first_spurious = false; 5049 } 5050 5051 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5052 name = fname == NULL ? "<unknown>" : fname->name; 5053 trace_print_obj(obj, name, obj->path, main_local, 5054 NULL, fmt2); 5055 } 5056 } 5057 } 5058 5059 /* 5060 * Unload a dlopened object and its dependencies from memory and from 5061 * our data structures. It is assumed that the DAG rooted in the 5062 * object has already been unreferenced, and that the object has a 5063 * reference count of 0. 5064 */ 5065 static void 5066 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5067 { 5068 Obj_Entry marker, *obj, *next; 5069 5070 assert(root->refcount == 0); 5071 5072 /* 5073 * Pass over the DAG removing unreferenced objects from 5074 * appropriate lists. 5075 */ 5076 unlink_object(root); 5077 5078 /* Unmap all objects that are no longer referenced. */ 5079 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5080 next = TAILQ_NEXT(obj, next); 5081 if (obj->marker || obj->refcount != 0) 5082 continue; 5083 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5084 obj->mapsize, 0, obj->path); 5085 dbg("unloading \"%s\"", obj->path); 5086 /* 5087 * Unlink the object now to prevent new references from 5088 * being acquired while the bind lock is dropped in 5089 * recursive dlclose() invocations. 5090 */ 5091 TAILQ_REMOVE(&obj_list, obj, next); 5092 obj_count--; 5093 5094 if (obj->filtees_loaded) { 5095 if (next != NULL) { 5096 init_marker(&marker); 5097 TAILQ_INSERT_BEFORE(next, &marker, next); 5098 unload_filtees(obj, lockstate); 5099 next = TAILQ_NEXT(&marker, next); 5100 TAILQ_REMOVE(&obj_list, &marker, next); 5101 } else 5102 unload_filtees(obj, lockstate); 5103 } 5104 release_object(obj); 5105 } 5106 } 5107 5108 static void 5109 unlink_object(Obj_Entry *root) 5110 { 5111 Objlist_Entry *elm; 5112 5113 if (root->refcount == 0) { 5114 /* Remove the object from the RTLD_GLOBAL list. */ 5115 objlist_remove(&list_global, root); 5116 5117 /* Remove the object from all objects' DAG lists. */ 5118 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5119 objlist_remove(&elm->obj->dldags, root); 5120 if (elm->obj != root) 5121 unlink_object(elm->obj); 5122 } 5123 } 5124 } 5125 5126 static void 5127 ref_dag(Obj_Entry *root) 5128 { 5129 Objlist_Entry *elm; 5130 5131 assert(root->dag_inited); 5132 STAILQ_FOREACH(elm, &root->dagmembers, link) 5133 elm->obj->refcount++; 5134 } 5135 5136 static void 5137 unref_dag(Obj_Entry *root) 5138 { 5139 Objlist_Entry *elm; 5140 5141 assert(root->dag_inited); 5142 STAILQ_FOREACH(elm, &root->dagmembers, link) 5143 elm->obj->refcount--; 5144 } 5145 5146 /* 5147 * Common code for MD __tls_get_addr(). 5148 */ 5149 static void * 5150 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5151 { 5152 Elf_Addr *newdtv, *dtv; 5153 RtldLockState lockstate; 5154 int to_copy; 5155 5156 dtv = *dtvp; 5157 /* Check dtv generation in case new modules have arrived */ 5158 if (dtv[0] != tls_dtv_generation) { 5159 if (!locked) 5160 wlock_acquire(rtld_bind_lock, &lockstate); 5161 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5162 to_copy = dtv[1]; 5163 if (to_copy > tls_max_index) 5164 to_copy = tls_max_index; 5165 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5166 newdtv[0] = tls_dtv_generation; 5167 newdtv[1] = tls_max_index; 5168 free(dtv); 5169 if (!locked) 5170 lock_release(rtld_bind_lock, &lockstate); 5171 dtv = *dtvp = newdtv; 5172 } 5173 5174 /* Dynamically allocate module TLS if necessary */ 5175 if (dtv[index + 1] == 0) { 5176 /* Signal safe, wlock will block out signals. */ 5177 if (!locked) 5178 wlock_acquire(rtld_bind_lock, &lockstate); 5179 if (!dtv[index + 1]) 5180 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5181 if (!locked) 5182 lock_release(rtld_bind_lock, &lockstate); 5183 } 5184 return ((void *)(dtv[index + 1] + offset)); 5185 } 5186 5187 void * 5188 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5189 { 5190 uintptr_t *dtv; 5191 5192 dtv = *dtvp; 5193 /* Check dtv generation in case new modules have arrived */ 5194 if (__predict_true(dtv[0] == tls_dtv_generation && 5195 dtv[index + 1] != 0)) 5196 return ((void *)(dtv[index + 1] + offset)); 5197 return (tls_get_addr_slow(dtvp, index, offset, false)); 5198 } 5199 5200 #ifdef TLS_VARIANT_I 5201 5202 /* 5203 * Return pointer to allocated TLS block 5204 */ 5205 static void * 5206 get_tls_block_ptr(void *tcb, size_t tcbsize) 5207 { 5208 size_t extra_size, post_size, pre_size, tls_block_size; 5209 size_t tls_init_align; 5210 5211 tls_init_align = MAX(obj_main->tlsalign, 1); 5212 5213 /* Compute fragments sizes. */ 5214 extra_size = tcbsize - TLS_TCB_SIZE; 5215 post_size = calculate_tls_post_size(tls_init_align); 5216 tls_block_size = tcbsize + post_size; 5217 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5218 5219 return ((char *)tcb - pre_size - extra_size); 5220 } 5221 5222 /* 5223 * Allocate Static TLS using the Variant I method. 5224 * 5225 * For details on the layout, see lib/libc/gen/tls.c. 5226 * 5227 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5228 * it is based on tls_last_offset, and TLS offsets here are really TCB 5229 * offsets, whereas libc's tls_static_space is just the executable's static 5230 * TLS segment. 5231 */ 5232 void * 5233 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5234 { 5235 Obj_Entry *obj; 5236 char *tls_block; 5237 Elf_Addr *dtv, **tcb; 5238 Elf_Addr addr; 5239 Elf_Addr i; 5240 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5241 size_t tls_init_align, tls_init_offset; 5242 5243 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5244 return (oldtcb); 5245 5246 assert(tcbsize >= TLS_TCB_SIZE); 5247 maxalign = MAX(tcbalign, tls_static_max_align); 5248 tls_init_align = MAX(obj_main->tlsalign, 1); 5249 5250 /* Compute fragmets sizes. */ 5251 extra_size = tcbsize - TLS_TCB_SIZE; 5252 post_size = calculate_tls_post_size(tls_init_align); 5253 tls_block_size = tcbsize + post_size; 5254 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5255 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5256 5257 /* Allocate whole TLS block */ 5258 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5259 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5260 5261 if (oldtcb != NULL) { 5262 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5263 tls_static_space); 5264 free(get_tls_block_ptr(oldtcb, tcbsize)); 5265 5266 /* Adjust the DTV. */ 5267 dtv = tcb[0]; 5268 for (i = 0; i < dtv[1]; i++) { 5269 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5270 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5271 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5272 } 5273 } 5274 } else { 5275 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5276 tcb[0] = dtv; 5277 dtv[0] = tls_dtv_generation; 5278 dtv[1] = tls_max_index; 5279 5280 for (obj = globallist_curr(objs); obj != NULL; 5281 obj = globallist_next(obj)) { 5282 if (obj->tlsoffset == 0) 5283 continue; 5284 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5285 addr = (Elf_Addr)tcb + obj->tlsoffset; 5286 if (tls_init_offset > 0) 5287 memset((void *)addr, 0, tls_init_offset); 5288 if (obj->tlsinitsize > 0) { 5289 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5290 obj->tlsinitsize); 5291 } 5292 if (obj->tlssize > obj->tlsinitsize) { 5293 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5294 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5295 } 5296 dtv[obj->tlsindex + 1] = addr; 5297 } 5298 } 5299 5300 return (tcb); 5301 } 5302 5303 void 5304 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5305 { 5306 Elf_Addr *dtv; 5307 Elf_Addr tlsstart, tlsend; 5308 size_t post_size; 5309 size_t dtvsize, i, tls_init_align __unused; 5310 5311 assert(tcbsize >= TLS_TCB_SIZE); 5312 tls_init_align = MAX(obj_main->tlsalign, 1); 5313 5314 /* Compute fragments sizes. */ 5315 post_size = calculate_tls_post_size(tls_init_align); 5316 5317 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5318 tlsend = (Elf_Addr)tcb + tls_static_space; 5319 5320 dtv = *(Elf_Addr **)tcb; 5321 dtvsize = dtv[1]; 5322 for (i = 0; i < dtvsize; i++) { 5323 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5324 free((void*)dtv[i+2]); 5325 } 5326 } 5327 free(dtv); 5328 free(get_tls_block_ptr(tcb, tcbsize)); 5329 } 5330 5331 #endif /* TLS_VARIANT_I */ 5332 5333 #ifdef TLS_VARIANT_II 5334 5335 /* 5336 * Allocate Static TLS using the Variant II method. 5337 */ 5338 void * 5339 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5340 { 5341 Obj_Entry *obj; 5342 size_t size, ralign; 5343 char *tls; 5344 Elf_Addr *dtv, *olddtv; 5345 Elf_Addr segbase, oldsegbase, addr; 5346 size_t i; 5347 5348 ralign = tcbalign; 5349 if (tls_static_max_align > ralign) 5350 ralign = tls_static_max_align; 5351 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5352 5353 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5354 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5355 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5356 5357 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5358 ((Elf_Addr *)segbase)[0] = segbase; 5359 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5360 5361 dtv[0] = tls_dtv_generation; 5362 dtv[1] = tls_max_index; 5363 5364 if (oldtls) { 5365 /* 5366 * Copy the static TLS block over whole. 5367 */ 5368 oldsegbase = (Elf_Addr) oldtls; 5369 memcpy((void *)(segbase - tls_static_space), 5370 (const void *)(oldsegbase - tls_static_space), 5371 tls_static_space); 5372 5373 /* 5374 * If any dynamic TLS blocks have been created tls_get_addr(), 5375 * move them over. 5376 */ 5377 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5378 for (i = 0; i < olddtv[1]; i++) { 5379 if (olddtv[i + 2] < oldsegbase - size || 5380 olddtv[i + 2] > oldsegbase) { 5381 dtv[i + 2] = olddtv[i + 2]; 5382 olddtv[i + 2] = 0; 5383 } 5384 } 5385 5386 /* 5387 * We assume that this block was the one we created with 5388 * allocate_initial_tls(). 5389 */ 5390 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5391 } else { 5392 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5393 if (obj->marker || obj->tlsoffset == 0) 5394 continue; 5395 addr = segbase - obj->tlsoffset; 5396 memset((void *)(addr + obj->tlsinitsize), 5397 0, obj->tlssize - obj->tlsinitsize); 5398 if (obj->tlsinit) { 5399 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5400 obj->static_tls_copied = true; 5401 } 5402 dtv[obj->tlsindex + 1] = addr; 5403 } 5404 } 5405 5406 return ((void *)segbase); 5407 } 5408 5409 void 5410 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5411 { 5412 Elf_Addr* dtv; 5413 size_t size, ralign; 5414 int dtvsize, i; 5415 Elf_Addr tlsstart, tlsend; 5416 5417 /* 5418 * Figure out the size of the initial TLS block so that we can 5419 * find stuff which ___tls_get_addr() allocated dynamically. 5420 */ 5421 ralign = tcbalign; 5422 if (tls_static_max_align > ralign) 5423 ralign = tls_static_max_align; 5424 size = roundup(tls_static_space, ralign); 5425 5426 dtv = ((Elf_Addr **)tls)[1]; 5427 dtvsize = dtv[1]; 5428 tlsend = (Elf_Addr)tls; 5429 tlsstart = tlsend - size; 5430 for (i = 0; i < dtvsize; i++) { 5431 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5432 dtv[i + 2] > tlsend)) { 5433 free((void *)dtv[i + 2]); 5434 } 5435 } 5436 5437 free((void *)tlsstart); 5438 free((void *)dtv); 5439 } 5440 5441 #endif /* TLS_VARIANT_II */ 5442 5443 /* 5444 * Allocate TLS block for module with given index. 5445 */ 5446 void * 5447 allocate_module_tls(int index) 5448 { 5449 Obj_Entry *obj; 5450 char *p; 5451 5452 TAILQ_FOREACH(obj, &obj_list, next) { 5453 if (obj->marker) 5454 continue; 5455 if (obj->tlsindex == index) 5456 break; 5457 } 5458 if (obj == NULL) { 5459 _rtld_error("Can't find module with TLS index %d", index); 5460 rtld_die(); 5461 } 5462 5463 if (obj->tls_static) { 5464 #ifdef TLS_VARIANT_I 5465 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5466 #else 5467 p = (char *)_tcb_get() - obj->tlsoffset; 5468 #endif 5469 return (p); 5470 } 5471 5472 obj->tls_dynamic = true; 5473 5474 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5475 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5476 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5477 return (p); 5478 } 5479 5480 bool 5481 allocate_tls_offset(Obj_Entry *obj) 5482 { 5483 size_t off; 5484 5485 if (obj->tls_dynamic) 5486 return (false); 5487 5488 if (obj->tls_static) 5489 return (true); 5490 5491 if (obj->tlssize == 0) { 5492 obj->tls_static = true; 5493 return (true); 5494 } 5495 5496 if (tls_last_offset == 0) 5497 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5498 obj->tlspoffset); 5499 else 5500 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5501 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5502 5503 obj->tlsoffset = off; 5504 #ifdef TLS_VARIANT_I 5505 off += obj->tlssize; 5506 #endif 5507 5508 /* 5509 * If we have already fixed the size of the static TLS block, we 5510 * must stay within that size. When allocating the static TLS, we 5511 * leave a small amount of space spare to be used for dynamically 5512 * loading modules which use static TLS. 5513 */ 5514 if (tls_static_space != 0) { 5515 if (off > tls_static_space) 5516 return (false); 5517 } else if (obj->tlsalign > tls_static_max_align) { 5518 tls_static_max_align = obj->tlsalign; 5519 } 5520 5521 tls_last_offset = off; 5522 tls_last_size = obj->tlssize; 5523 obj->tls_static = true; 5524 5525 return (true); 5526 } 5527 5528 void 5529 free_tls_offset(Obj_Entry *obj) 5530 { 5531 5532 /* 5533 * If we were the last thing to allocate out of the static TLS 5534 * block, we give our space back to the 'allocator'. This is a 5535 * simplistic workaround to allow libGL.so.1 to be loaded and 5536 * unloaded multiple times. 5537 */ 5538 size_t off = obj->tlsoffset; 5539 #ifdef TLS_VARIANT_I 5540 off += obj->tlssize; 5541 #endif 5542 if (off == tls_last_offset) { 5543 tls_last_offset -= obj->tlssize; 5544 tls_last_size = 0; 5545 } 5546 } 5547 5548 void * 5549 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5550 { 5551 void *ret; 5552 RtldLockState lockstate; 5553 5554 wlock_acquire(rtld_bind_lock, &lockstate); 5555 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5556 tcbsize, tcbalign); 5557 lock_release(rtld_bind_lock, &lockstate); 5558 return (ret); 5559 } 5560 5561 void 5562 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5563 { 5564 RtldLockState lockstate; 5565 5566 wlock_acquire(rtld_bind_lock, &lockstate); 5567 free_tls(tcb, tcbsize, tcbalign); 5568 lock_release(rtld_bind_lock, &lockstate); 5569 } 5570 5571 static void 5572 object_add_name(Obj_Entry *obj, const char *name) 5573 { 5574 Name_Entry *entry; 5575 size_t len; 5576 5577 len = strlen(name); 5578 entry = malloc(sizeof(Name_Entry) + len); 5579 5580 if (entry != NULL) { 5581 strcpy(entry->name, name); 5582 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5583 } 5584 } 5585 5586 static int 5587 object_match_name(const Obj_Entry *obj, const char *name) 5588 { 5589 Name_Entry *entry; 5590 5591 STAILQ_FOREACH(entry, &obj->names, link) { 5592 if (strcmp(name, entry->name) == 0) 5593 return (1); 5594 } 5595 return (0); 5596 } 5597 5598 static Obj_Entry * 5599 locate_dependency(const Obj_Entry *obj, const char *name) 5600 { 5601 const Objlist_Entry *entry; 5602 const Needed_Entry *needed; 5603 5604 STAILQ_FOREACH(entry, &list_main, link) { 5605 if (object_match_name(entry->obj, name)) 5606 return (entry->obj); 5607 } 5608 5609 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5610 if (strcmp(obj->strtab + needed->name, name) == 0 || 5611 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5612 /* 5613 * If there is DT_NEEDED for the name we are looking for, 5614 * we are all set. Note that object might not be found if 5615 * dependency was not loaded yet, so the function can 5616 * return NULL here. This is expected and handled 5617 * properly by the caller. 5618 */ 5619 return (needed->obj); 5620 } 5621 } 5622 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5623 obj->path, name); 5624 rtld_die(); 5625 } 5626 5627 static int 5628 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5629 const Elf_Vernaux *vna) 5630 { 5631 const Elf_Verdef *vd; 5632 const char *vername; 5633 5634 vername = refobj->strtab + vna->vna_name; 5635 vd = depobj->verdef; 5636 if (vd == NULL) { 5637 _rtld_error("%s: version %s required by %s not defined", 5638 depobj->path, vername, refobj->path); 5639 return (-1); 5640 } 5641 for (;;) { 5642 if (vd->vd_version != VER_DEF_CURRENT) { 5643 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5644 depobj->path, vd->vd_version); 5645 return (-1); 5646 } 5647 if (vna->vna_hash == vd->vd_hash) { 5648 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5649 ((const char *)vd + vd->vd_aux); 5650 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5651 return (0); 5652 } 5653 if (vd->vd_next == 0) 5654 break; 5655 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5656 } 5657 if (vna->vna_flags & VER_FLG_WEAK) 5658 return (0); 5659 _rtld_error("%s: version %s required by %s not found", 5660 depobj->path, vername, refobj->path); 5661 return (-1); 5662 } 5663 5664 static int 5665 rtld_verify_object_versions(Obj_Entry *obj) 5666 { 5667 const Elf_Verneed *vn; 5668 const Elf_Verdef *vd; 5669 const Elf_Verdaux *vda; 5670 const Elf_Vernaux *vna; 5671 const Obj_Entry *depobj; 5672 int maxvernum, vernum; 5673 5674 if (obj->ver_checked) 5675 return (0); 5676 obj->ver_checked = true; 5677 5678 maxvernum = 0; 5679 /* 5680 * Walk over defined and required version records and figure out 5681 * max index used by any of them. Do very basic sanity checking 5682 * while there. 5683 */ 5684 vn = obj->verneed; 5685 while (vn != NULL) { 5686 if (vn->vn_version != VER_NEED_CURRENT) { 5687 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5688 obj->path, vn->vn_version); 5689 return (-1); 5690 } 5691 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5692 for (;;) { 5693 vernum = VER_NEED_IDX(vna->vna_other); 5694 if (vernum > maxvernum) 5695 maxvernum = vernum; 5696 if (vna->vna_next == 0) 5697 break; 5698 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5699 } 5700 if (vn->vn_next == 0) 5701 break; 5702 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5703 } 5704 5705 vd = obj->verdef; 5706 while (vd != NULL) { 5707 if (vd->vd_version != VER_DEF_CURRENT) { 5708 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5709 obj->path, vd->vd_version); 5710 return (-1); 5711 } 5712 vernum = VER_DEF_IDX(vd->vd_ndx); 5713 if (vernum > maxvernum) 5714 maxvernum = vernum; 5715 if (vd->vd_next == 0) 5716 break; 5717 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5718 } 5719 5720 if (maxvernum == 0) 5721 return (0); 5722 5723 /* 5724 * Store version information in array indexable by version index. 5725 * Verify that object version requirements are satisfied along the 5726 * way. 5727 */ 5728 obj->vernum = maxvernum + 1; 5729 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5730 5731 vd = obj->verdef; 5732 while (vd != NULL) { 5733 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5734 vernum = VER_DEF_IDX(vd->vd_ndx); 5735 assert(vernum <= maxvernum); 5736 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5737 obj->vertab[vernum].hash = vd->vd_hash; 5738 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5739 obj->vertab[vernum].file = NULL; 5740 obj->vertab[vernum].flags = 0; 5741 } 5742 if (vd->vd_next == 0) 5743 break; 5744 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5745 } 5746 5747 vn = obj->verneed; 5748 while (vn != NULL) { 5749 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5750 if (depobj == NULL) 5751 return (-1); 5752 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5753 for (;;) { 5754 if (check_object_provided_version(obj, depobj, vna)) 5755 return (-1); 5756 vernum = VER_NEED_IDX(vna->vna_other); 5757 assert(vernum <= maxvernum); 5758 obj->vertab[vernum].hash = vna->vna_hash; 5759 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5760 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5761 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5762 VER_INFO_HIDDEN : 0; 5763 if (vna->vna_next == 0) 5764 break; 5765 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5766 } 5767 if (vn->vn_next == 0) 5768 break; 5769 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5770 } 5771 return (0); 5772 } 5773 5774 static int 5775 rtld_verify_versions(const Objlist *objlist) 5776 { 5777 Objlist_Entry *entry; 5778 int rc; 5779 5780 rc = 0; 5781 STAILQ_FOREACH(entry, objlist, link) { 5782 /* 5783 * Skip dummy objects or objects that have their version requirements 5784 * already checked. 5785 */ 5786 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5787 continue; 5788 if (rtld_verify_object_versions(entry->obj) == -1) { 5789 rc = -1; 5790 if (ld_tracing == NULL) 5791 break; 5792 } 5793 } 5794 if (rc == 0 || ld_tracing != NULL) 5795 rc = rtld_verify_object_versions(&obj_rtld); 5796 return (rc); 5797 } 5798 5799 const Ver_Entry * 5800 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5801 { 5802 Elf_Versym vernum; 5803 5804 if (obj->vertab) { 5805 vernum = VER_NDX(obj->versyms[symnum]); 5806 if (vernum >= obj->vernum) { 5807 _rtld_error("%s: symbol %s has wrong verneed value %d", 5808 obj->path, obj->strtab + symnum, vernum); 5809 } else if (obj->vertab[vernum].hash != 0) { 5810 return (&obj->vertab[vernum]); 5811 } 5812 } 5813 return (NULL); 5814 } 5815 5816 int 5817 _rtld_get_stack_prot(void) 5818 { 5819 5820 return (stack_prot); 5821 } 5822 5823 int 5824 _rtld_is_dlopened(void *arg) 5825 { 5826 Obj_Entry *obj; 5827 RtldLockState lockstate; 5828 int res; 5829 5830 rlock_acquire(rtld_bind_lock, &lockstate); 5831 obj = dlcheck(arg); 5832 if (obj == NULL) 5833 obj = obj_from_addr(arg); 5834 if (obj == NULL) { 5835 _rtld_error("No shared object contains address"); 5836 lock_release(rtld_bind_lock, &lockstate); 5837 return (-1); 5838 } 5839 res = obj->dlopened ? 1 : 0; 5840 lock_release(rtld_bind_lock, &lockstate); 5841 return (res); 5842 } 5843 5844 static int 5845 obj_remap_relro(Obj_Entry *obj, int prot) 5846 { 5847 5848 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5849 prot) == -1) { 5850 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5851 obj->path, prot, rtld_strerror(errno)); 5852 return (-1); 5853 } 5854 return (0); 5855 } 5856 5857 static int 5858 obj_disable_relro(Obj_Entry *obj) 5859 { 5860 5861 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5862 } 5863 5864 static int 5865 obj_enforce_relro(Obj_Entry *obj) 5866 { 5867 5868 return (obj_remap_relro(obj, PROT_READ)); 5869 } 5870 5871 static void 5872 map_stacks_exec(RtldLockState *lockstate) 5873 { 5874 void (*thr_map_stacks_exec)(void); 5875 5876 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5877 return; 5878 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5879 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5880 if (thr_map_stacks_exec != NULL) { 5881 stack_prot |= PROT_EXEC; 5882 thr_map_stacks_exec(); 5883 } 5884 } 5885 5886 static void 5887 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5888 { 5889 Objlist_Entry *elm; 5890 Obj_Entry *obj; 5891 void (*distrib)(size_t, void *, size_t, size_t); 5892 5893 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5894 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5895 if (distrib == NULL) 5896 return; 5897 STAILQ_FOREACH(elm, list, link) { 5898 obj = elm->obj; 5899 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5900 continue; 5901 lock_release(rtld_bind_lock, lockstate); 5902 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5903 obj->tlssize); 5904 wlock_acquire(rtld_bind_lock, lockstate); 5905 obj->static_tls_copied = true; 5906 } 5907 } 5908 5909 void 5910 symlook_init(SymLook *dst, const char *name) 5911 { 5912 5913 bzero(dst, sizeof(*dst)); 5914 dst->name = name; 5915 dst->hash = elf_hash(name); 5916 dst->hash_gnu = gnu_hash(name); 5917 } 5918 5919 static void 5920 symlook_init_from_req(SymLook *dst, const SymLook *src) 5921 { 5922 5923 dst->name = src->name; 5924 dst->hash = src->hash; 5925 dst->hash_gnu = src->hash_gnu; 5926 dst->ventry = src->ventry; 5927 dst->flags = src->flags; 5928 dst->defobj_out = NULL; 5929 dst->sym_out = NULL; 5930 dst->lockstate = src->lockstate; 5931 } 5932 5933 static int 5934 open_binary_fd(const char *argv0, bool search_in_path, 5935 const char **binpath_res) 5936 { 5937 char *binpath, *pathenv, *pe, *res1; 5938 const char *res; 5939 int fd; 5940 5941 binpath = NULL; 5942 res = NULL; 5943 if (search_in_path && strchr(argv0, '/') == NULL) { 5944 binpath = xmalloc(PATH_MAX); 5945 pathenv = getenv("PATH"); 5946 if (pathenv == NULL) { 5947 _rtld_error("-p and no PATH environment variable"); 5948 rtld_die(); 5949 } 5950 pathenv = strdup(pathenv); 5951 if (pathenv == NULL) { 5952 _rtld_error("Cannot allocate memory"); 5953 rtld_die(); 5954 } 5955 fd = -1; 5956 errno = ENOENT; 5957 while ((pe = strsep(&pathenv, ":")) != NULL) { 5958 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5959 continue; 5960 if (binpath[0] != '\0' && 5961 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5962 continue; 5963 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5964 continue; 5965 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5966 if (fd != -1 || errno != ENOENT) { 5967 res = binpath; 5968 break; 5969 } 5970 } 5971 free(pathenv); 5972 } else { 5973 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5974 res = argv0; 5975 } 5976 5977 if (fd == -1) { 5978 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5979 rtld_die(); 5980 } 5981 if (res != NULL && res[0] != '/') { 5982 res1 = xmalloc(PATH_MAX); 5983 if (realpath(res, res1) != NULL) { 5984 if (res != argv0) 5985 free(__DECONST(char *, res)); 5986 res = res1; 5987 } else { 5988 free(res1); 5989 } 5990 } 5991 *binpath_res = res; 5992 return (fd); 5993 } 5994 5995 /* 5996 * Parse a set of command-line arguments. 5997 */ 5998 static int 5999 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6000 const char **argv0, bool *dir_ignore) 6001 { 6002 const char *arg; 6003 char machine[64]; 6004 size_t sz; 6005 int arglen, fd, i, j, mib[2]; 6006 char opt; 6007 bool seen_b, seen_f; 6008 6009 dbg("Parsing command-line arguments"); 6010 *use_pathp = false; 6011 *fdp = -1; 6012 *dir_ignore = false; 6013 seen_b = seen_f = false; 6014 6015 for (i = 1; i < argc; i++ ) { 6016 arg = argv[i]; 6017 dbg("argv[%d]: '%s'", i, arg); 6018 6019 /* 6020 * rtld arguments end with an explicit "--" or with the first 6021 * non-prefixed argument. 6022 */ 6023 if (strcmp(arg, "--") == 0) { 6024 i++; 6025 break; 6026 } 6027 if (arg[0] != '-') 6028 break; 6029 6030 /* 6031 * All other arguments are single-character options that can 6032 * be combined, so we need to search through `arg` for them. 6033 */ 6034 arglen = strlen(arg); 6035 for (j = 1; j < arglen; j++) { 6036 opt = arg[j]; 6037 if (opt == 'h') { 6038 print_usage(argv[0]); 6039 _exit(0); 6040 } else if (opt == 'b') { 6041 if (seen_f) { 6042 _rtld_error("Both -b and -f specified"); 6043 rtld_die(); 6044 } 6045 if (j != arglen - 1) { 6046 _rtld_error("Invalid options: %s", arg); 6047 rtld_die(); 6048 } 6049 i++; 6050 *argv0 = argv[i]; 6051 seen_b = true; 6052 break; 6053 } else if (opt == 'd') { 6054 *dir_ignore = true; 6055 } else if (opt == 'f') { 6056 if (seen_b) { 6057 _rtld_error("Both -b and -f specified"); 6058 rtld_die(); 6059 } 6060 6061 /* 6062 * -f XX can be used to specify a 6063 * descriptor for the binary named at 6064 * the command line (i.e., the later 6065 * argument will specify the process 6066 * name but the descriptor is what 6067 * will actually be executed). 6068 * 6069 * -f must be the last option in the 6070 * group, e.g., -abcf <fd>. 6071 */ 6072 if (j != arglen - 1) { 6073 _rtld_error("Invalid options: %s", arg); 6074 rtld_die(); 6075 } 6076 i++; 6077 fd = parse_integer(argv[i]); 6078 if (fd == -1) { 6079 _rtld_error( 6080 "Invalid file descriptor: '%s'", 6081 argv[i]); 6082 rtld_die(); 6083 } 6084 *fdp = fd; 6085 seen_f = true; 6086 break; 6087 } else if (opt == 'p') { 6088 *use_pathp = true; 6089 } else if (opt == 'u') { 6090 trust = false; 6091 } else if (opt == 'v') { 6092 machine[0] = '\0'; 6093 mib[0] = CTL_HW; 6094 mib[1] = HW_MACHINE; 6095 sz = sizeof(machine); 6096 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6097 ld_elf_hints_path = ld_get_env_var( 6098 LD_ELF_HINTS_PATH); 6099 set_ld_elf_hints_path(); 6100 rtld_printf( 6101 "FreeBSD ld-elf.so.1 %s\n" 6102 "FreeBSD_version %d\n" 6103 "Default lib path %s\n" 6104 "Hints lib path %s\n" 6105 "Env prefix %s\n" 6106 "Default hint file %s\n" 6107 "Hint file %s\n" 6108 "libmap file %s\n", 6109 machine, 6110 __FreeBSD_version, ld_standard_library_path, 6111 gethints(false), 6112 ld_env_prefix, ld_elf_hints_default, 6113 ld_elf_hints_path, 6114 ld_path_libmap_conf); 6115 _exit(0); 6116 } else { 6117 _rtld_error("Invalid argument: '%s'", arg); 6118 print_usage(argv[0]); 6119 rtld_die(); 6120 } 6121 } 6122 } 6123 6124 if (!seen_b) 6125 *argv0 = argv[i]; 6126 return (i); 6127 } 6128 6129 /* 6130 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6131 */ 6132 static int 6133 parse_integer(const char *str) 6134 { 6135 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6136 const char *orig; 6137 int n; 6138 char c; 6139 6140 orig = str; 6141 n = 0; 6142 for (c = *str; c != '\0'; c = *++str) { 6143 if (c < '0' || c > '9') 6144 return (-1); 6145 6146 n *= RADIX; 6147 n += c - '0'; 6148 } 6149 6150 /* Make sure we actually parsed something. */ 6151 if (str == orig) 6152 return (-1); 6153 return (n); 6154 } 6155 6156 static void 6157 print_usage(const char *argv0) 6158 { 6159 6160 rtld_printf( 6161 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6162 "\n" 6163 "Options:\n" 6164 " -h Display this help message\n" 6165 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6166 " -d Ignore lack of exec permissions for the binary\n" 6167 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6168 " -p Search in PATH for named binary\n" 6169 " -u Ignore LD_ environment variables\n" 6170 " -v Display identification information\n" 6171 " -- End of RTLD options\n" 6172 " <binary> Name of process to execute\n" 6173 " <args> Arguments to the executed process\n", argv0); 6174 } 6175 6176 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6177 static const struct auxfmt { 6178 const char *name; 6179 const char *fmt; 6180 } auxfmts[] = { 6181 AUXFMT(AT_NULL, NULL), 6182 AUXFMT(AT_IGNORE, NULL), 6183 AUXFMT(AT_EXECFD, "%ld"), 6184 AUXFMT(AT_PHDR, "%p"), 6185 AUXFMT(AT_PHENT, "%lu"), 6186 AUXFMT(AT_PHNUM, "%lu"), 6187 AUXFMT(AT_PAGESZ, "%lu"), 6188 AUXFMT(AT_BASE, "%#lx"), 6189 AUXFMT(AT_FLAGS, "%#lx"), 6190 AUXFMT(AT_ENTRY, "%p"), 6191 AUXFMT(AT_NOTELF, NULL), 6192 AUXFMT(AT_UID, "%ld"), 6193 AUXFMT(AT_EUID, "%ld"), 6194 AUXFMT(AT_GID, "%ld"), 6195 AUXFMT(AT_EGID, "%ld"), 6196 AUXFMT(AT_EXECPATH, "%s"), 6197 AUXFMT(AT_CANARY, "%p"), 6198 AUXFMT(AT_CANARYLEN, "%lu"), 6199 AUXFMT(AT_OSRELDATE, "%lu"), 6200 AUXFMT(AT_NCPUS, "%lu"), 6201 AUXFMT(AT_PAGESIZES, "%p"), 6202 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6203 AUXFMT(AT_TIMEKEEP, "%p"), 6204 AUXFMT(AT_STACKPROT, "%#lx"), 6205 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6206 AUXFMT(AT_HWCAP, "%#lx"), 6207 AUXFMT(AT_HWCAP2, "%#lx"), 6208 AUXFMT(AT_BSDFLAGS, "%#lx"), 6209 AUXFMT(AT_ARGC, "%lu"), 6210 AUXFMT(AT_ARGV, "%p"), 6211 AUXFMT(AT_ENVC, "%p"), 6212 AUXFMT(AT_ENVV, "%p"), 6213 AUXFMT(AT_PS_STRINGS, "%p"), 6214 AUXFMT(AT_FXRNG, "%p"), 6215 AUXFMT(AT_KPRELOAD, "%p"), 6216 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6217 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6218 }; 6219 6220 static bool 6221 is_ptr_fmt(const char *fmt) 6222 { 6223 char last; 6224 6225 last = fmt[strlen(fmt) - 1]; 6226 return (last == 'p' || last == 's'); 6227 } 6228 6229 static void 6230 dump_auxv(Elf_Auxinfo **aux_info) 6231 { 6232 Elf_Auxinfo *auxp; 6233 const struct auxfmt *fmt; 6234 int i; 6235 6236 for (i = 0; i < AT_COUNT; i++) { 6237 auxp = aux_info[i]; 6238 if (auxp == NULL) 6239 continue; 6240 fmt = &auxfmts[i]; 6241 if (fmt->fmt == NULL) 6242 continue; 6243 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6244 if (is_ptr_fmt(fmt->fmt)) { 6245 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6246 auxp->a_un.a_ptr); 6247 } else { 6248 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6249 auxp->a_un.a_val); 6250 } 6251 rtld_fdprintf(STDOUT_FILENO, "\n"); 6252 } 6253 } 6254 6255 /* 6256 * Overrides for libc_pic-provided functions. 6257 */ 6258 6259 int 6260 __getosreldate(void) 6261 { 6262 size_t len; 6263 int oid[2]; 6264 int error, osrel; 6265 6266 if (osreldate != 0) 6267 return (osreldate); 6268 6269 oid[0] = CTL_KERN; 6270 oid[1] = KERN_OSRELDATE; 6271 osrel = 0; 6272 len = sizeof(osrel); 6273 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6274 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6275 osreldate = osrel; 6276 return (osreldate); 6277 } 6278 const char * 6279 rtld_strerror(int errnum) 6280 { 6281 6282 if (errnum < 0 || errnum >= sys_nerr) 6283 return ("Unknown error"); 6284 return (sys_errlist[errnum]); 6285 } 6286 6287 char * 6288 getenv(const char *name) 6289 { 6290 return (__DECONST(char *, rtld_get_env_val(environ, name, 6291 strlen(name)))); 6292 } 6293 6294 /* malloc */ 6295 void * 6296 malloc(size_t nbytes) 6297 { 6298 6299 return (__crt_malloc(nbytes)); 6300 } 6301 6302 void * 6303 calloc(size_t num, size_t size) 6304 { 6305 6306 return (__crt_calloc(num, size)); 6307 } 6308 6309 void 6310 free(void *cp) 6311 { 6312 6313 __crt_free(cp); 6314 } 6315 6316 void * 6317 realloc(void *cp, size_t nbytes) 6318 { 6319 6320 return (__crt_realloc(cp, nbytes)); 6321 } 6322 6323 extern int _rtld_version__FreeBSD_version __exported; 6324 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6325 6326 extern char _rtld_version_laddr_offset __exported; 6327 char _rtld_version_laddr_offset; 6328 6329 extern char _rtld_version_dlpi_tls_data __exported; 6330 char _rtld_version_dlpi_tls_data; 6331