1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <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 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_utrace.h" 70 #include "notes.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 81 const Elf_Dyn **, const Elf_Dyn **); 82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 83 const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static int dlclose_locked(void *, RtldLockState *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *, int *); 97 static const char *gethints(bool); 98 static void hold_object(Obj_Entry *); 99 static void unhold_object(Obj_Entry *); 100 static void init_dag(Obj_Entry *); 101 static void init_marker(Obj_Entry *); 102 static void init_pagesizes(Elf_Auxinfo **aux_info); 103 static void init_rtld(caddr_t, Elf_Auxinfo **); 104 static void initlist_add_neededs(Needed_Entry *, Objlist *); 105 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 106 static void linkmap_add(Obj_Entry *); 107 static void linkmap_delete(Obj_Entry *); 108 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 109 static void unload_filtees(Obj_Entry *, RtldLockState *); 110 static int load_needed_objects(Obj_Entry *, int); 111 static int load_preload_objects(void); 112 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 113 static void map_stacks_exec(RtldLockState *); 114 static int obj_enforce_relro(Obj_Entry *); 115 static Obj_Entry *obj_from_addr(const void *); 116 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 117 static void objlist_call_init(Objlist *, RtldLockState *); 118 static void objlist_clear(Objlist *); 119 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 120 static void objlist_init(Objlist *); 121 static void objlist_push_head(Objlist *, Obj_Entry *); 122 static void objlist_push_tail(Objlist *, Obj_Entry *); 123 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 124 static void objlist_remove(Objlist *, Obj_Entry *); 125 static int open_binary_fd(const char *argv0, bool search_in_path); 126 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 127 static int parse_integer(const char *); 128 static void *path_enumerate(const char *, path_enum_proc, void *); 129 static void print_usage(const char *argv0); 130 static void release_object(Obj_Entry *); 131 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 132 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 133 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 134 int flags, RtldLockState *lockstate); 135 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 136 RtldLockState *); 137 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 138 int flags, RtldLockState *lockstate); 139 static int rtld_dirname(const char *, char *); 140 static int rtld_dirname_abs(const char *, char *); 141 static void *rtld_dlopen(const char *name, int fd, int mode); 142 static void rtld_exit(void); 143 static char *search_library_path(const char *, const char *, int *); 144 static char *search_library_pathfds(const char *, const char *, int *); 145 static const void **get_program_var_addr(const char *, RtldLockState *); 146 static void set_program_var(const char *, const void *); 147 static int symlook_default(SymLook *, const Obj_Entry *refobj); 148 static int symlook_global(SymLook *, DoneList *); 149 static void symlook_init_from_req(SymLook *, const SymLook *); 150 static int symlook_list(SymLook *, const Objlist *, DoneList *); 151 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 152 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 153 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 154 static void trace_loaded_objects(Obj_Entry *); 155 static void unlink_object(Obj_Entry *); 156 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 157 static void unref_dag(Obj_Entry *); 158 static void ref_dag(Obj_Entry *); 159 static char *origin_subst_one(Obj_Entry *, char *, const char *, 160 const char *, bool); 161 static char *origin_subst(Obj_Entry *, char *); 162 static bool obj_resolve_origin(Obj_Entry *obj); 163 static void preinit_main(void); 164 static int rtld_verify_versions(const Objlist *); 165 static int rtld_verify_object_versions(Obj_Entry *); 166 static void object_add_name(Obj_Entry *, const char *); 167 static int object_match_name(const Obj_Entry *, const char *); 168 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 169 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 170 struct dl_phdr_info *phdr_info); 171 static uint32_t gnu_hash(const char *); 172 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 173 const unsigned long); 174 175 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 176 void _r_debug_postinit(struct link_map *) __noinline __exported; 177 178 int __sys_openat(int, const char *, int, ...); 179 180 /* 181 * Data declarations. 182 */ 183 static char *error_message; /* Message for dlerror(), or NULL */ 184 struct r_debug r_debug __exported; /* for GDB; */ 185 static bool libmap_disable; /* Disable libmap */ 186 static bool ld_loadfltr; /* Immediate filters processing */ 187 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 188 static bool trust; /* False for setuid and setgid programs */ 189 static bool dangerous_ld_env; /* True if environment variables have been 190 used to affect the libraries loaded */ 191 bool ld_bind_not; /* Disable PLT update */ 192 static char *ld_bind_now; /* Environment variable for immediate binding */ 193 static char *ld_debug; /* Environment variable for debugging */ 194 static char *ld_library_path; /* Environment variable for search path */ 195 static char *ld_library_dirs; /* Environment variable for library descriptors */ 196 static char *ld_preload; /* Environment variable for libraries to 197 load first */ 198 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 199 static char *ld_tracing; /* Called from ldd to print libs */ 200 static char *ld_utrace; /* Use utrace() to log events. */ 201 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 202 static Obj_Entry *obj_main; /* The main program shared object */ 203 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 204 static unsigned int obj_count; /* Number of objects in obj_list */ 205 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 206 207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 208 STAILQ_HEAD_INITIALIZER(list_global); 209 static Objlist list_main = /* Objects loaded at program startup */ 210 STAILQ_HEAD_INITIALIZER(list_main); 211 static Objlist list_fini = /* Objects needing fini() calls */ 212 STAILQ_HEAD_INITIALIZER(list_fini); 213 214 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 215 216 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 217 218 extern Elf_Dyn _DYNAMIC; 219 #pragma weak _DYNAMIC 220 221 int dlclose(void *) __exported; 222 char *dlerror(void) __exported; 223 void *dlopen(const char *, int) __exported; 224 void *fdlopen(int, int) __exported; 225 void *dlsym(void *, const char *) __exported; 226 dlfunc_t dlfunc(void *, const char *) __exported; 227 void *dlvsym(void *, const char *, const char *) __exported; 228 int dladdr(const void *, Dl_info *) __exported; 229 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 230 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 231 int dlinfo(void *, int , void *) __exported; 232 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 233 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 234 int _rtld_get_stack_prot(void) __exported; 235 int _rtld_is_dlopened(void *) __exported; 236 void _rtld_error(const char *, ...) __exported; 237 238 int npagesizes, osreldate; 239 size_t *pagesizes; 240 241 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 242 243 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 244 static int max_stack_flags; 245 246 /* 247 * Global declarations normally provided by crt1. The dynamic linker is 248 * not built with crt1, so we have to provide them ourselves. 249 */ 250 char *__progname; 251 char **environ; 252 253 /* 254 * Used to pass argc, argv to init functions. 255 */ 256 int main_argc; 257 char **main_argv; 258 259 /* 260 * Globals to control TLS allocation. 261 */ 262 size_t tls_last_offset; /* Static TLS offset of last module */ 263 size_t tls_last_size; /* Static TLS size of last module */ 264 size_t tls_static_space; /* Static TLS space allocated */ 265 size_t tls_static_max_align; 266 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 267 int tls_max_index = 1; /* Largest module index allocated */ 268 269 bool ld_library_path_rpath = false; 270 271 /* 272 * Globals for path names, and such 273 */ 274 char *ld_elf_hints_default = _PATH_ELF_HINTS; 275 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 276 char *ld_path_rtld = _PATH_RTLD; 277 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 278 char *ld_env_prefix = LD_; 279 280 /* 281 * Fill in a DoneList with an allocation large enough to hold all of 282 * the currently-loaded objects. Keep this as a macro since it calls 283 * alloca and we want that to occur within the scope of the caller. 284 */ 285 #define donelist_init(dlp) \ 286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 287 assert((dlp)->objs != NULL), \ 288 (dlp)->num_alloc = obj_count, \ 289 (dlp)->num_used = 0) 290 291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294 } while (0) 295 296 static void 297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299 { 300 struct utrace_rtld ut; 301 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 302 303 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 #ifdef RTLD_VARIANT_ENV_NAMES 316 /* 317 * construct the env variable based on the type of binary that's 318 * running. 319 */ 320 static inline const char * 321 _LD(const char *var) 322 { 323 static char buffer[128]; 324 325 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 326 strlcat(buffer, var, sizeof(buffer)); 327 return (buffer); 328 } 329 #else 330 #define _LD(x) LD_ x 331 #endif 332 333 /* 334 * Main entry point for dynamic linking. The first argument is the 335 * stack pointer. The stack is expected to be laid out as described 336 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 337 * Specifically, the stack pointer points to a word containing 338 * ARGC. Following that in the stack is a null-terminated sequence 339 * of pointers to argument strings. Then comes a null-terminated 340 * sequence of pointers to environment strings. Finally, there is a 341 * sequence of "auxiliary vector" entries. 342 * 343 * The second argument points to a place to store the dynamic linker's 344 * exit procedure pointer and the third to a place to store the main 345 * program's object. 346 * 347 * The return value is the main program's entry point. 348 */ 349 func_ptr_type 350 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 351 { 352 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 353 Objlist_Entry *entry; 354 Obj_Entry *last_interposer, *obj, *preload_tail; 355 const Elf_Phdr *phdr; 356 Objlist initlist; 357 RtldLockState lockstate; 358 struct stat st; 359 Elf_Addr *argcp; 360 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 361 caddr_t imgentry; 362 char buf[MAXPATHLEN]; 363 int argc, fd, i, mib[2], phnum, rtld_argc; 364 size_t len; 365 bool dir_enable, explicit_fd, search_in_path; 366 367 /* 368 * On entry, the dynamic linker itself has not been relocated yet. 369 * Be very careful not to reference any global data until after 370 * init_rtld has returned. It is OK to reference file-scope statics 371 * and string constants, and to call static and global functions. 372 */ 373 374 /* Find the auxiliary vector on the stack. */ 375 argcp = sp; 376 argc = *sp++; 377 argv = (char **) sp; 378 sp += argc + 1; /* Skip over arguments and NULL terminator */ 379 env = (char **) sp; 380 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 381 ; 382 aux = (Elf_Auxinfo *) sp; 383 384 /* Digest the auxiliary vector. */ 385 for (i = 0; i < AT_COUNT; i++) 386 aux_info[i] = NULL; 387 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 388 if (auxp->a_type < AT_COUNT) 389 aux_info[auxp->a_type] = auxp; 390 } 391 392 /* Initialize and relocate ourselves. */ 393 assert(aux_info[AT_BASE] != NULL); 394 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 395 396 __progname = obj_rtld.path; 397 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 398 environ = env; 399 main_argc = argc; 400 main_argv = argv; 401 402 if (aux_info[AT_CANARY] != NULL && 403 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 404 i = aux_info[AT_CANARYLEN]->a_un.a_val; 405 if (i > sizeof(__stack_chk_guard)) 406 i = sizeof(__stack_chk_guard); 407 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 408 } else { 409 mib[0] = CTL_KERN; 410 mib[1] = KERN_ARND; 411 412 len = sizeof(__stack_chk_guard); 413 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 414 len != sizeof(__stack_chk_guard)) { 415 /* If sysctl was unsuccessful, use the "terminator canary". */ 416 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 417 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 418 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 419 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 420 } 421 } 422 423 trust = !issetugid(); 424 425 md_abi_variant_hook(aux_info); 426 427 fd = -1; 428 if (aux_info[AT_EXECFD] != NULL) { 429 fd = aux_info[AT_EXECFD]->a_un.a_val; 430 } else { 431 assert(aux_info[AT_PHDR] != NULL); 432 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 433 if (phdr == obj_rtld.phdr) { 434 if (!trust) { 435 rtld_printf("Tainted process refusing to run binary %s\n", 436 argv0); 437 rtld_die(); 438 } 439 dbg("opening main program in direct exec mode"); 440 if (argc >= 2) { 441 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 442 argv0 = argv[rtld_argc]; 443 explicit_fd = (fd != -1); 444 if (!explicit_fd) 445 fd = open_binary_fd(argv0, search_in_path); 446 if (fstat(fd, &st) == -1) { 447 _rtld_error("failed to fstat FD %d (%s): %s", fd, 448 explicit_fd ? "user-provided descriptor" : argv0, 449 rtld_strerror(errno)); 450 rtld_die(); 451 } 452 453 /* 454 * Rough emulation of the permission checks done by 455 * execve(2), only Unix DACs are checked, ACLs are 456 * ignored. Preserve the semantic of disabling owner 457 * to execute if owner x bit is cleared, even if 458 * others x bit is enabled. 459 * mmap(2) does not allow to mmap with PROT_EXEC if 460 * binary' file comes from noexec mount. We cannot 461 * set VV_TEXT on the binary. 462 */ 463 dir_enable = false; 464 if (st.st_uid == geteuid()) { 465 if ((st.st_mode & S_IXUSR) != 0) 466 dir_enable = true; 467 } else if (st.st_gid == getegid()) { 468 if ((st.st_mode & S_IXGRP) != 0) 469 dir_enable = true; 470 } else if ((st.st_mode & S_IXOTH) != 0) { 471 dir_enable = true; 472 } 473 if (!dir_enable) { 474 rtld_printf("No execute permission for binary %s\n", 475 argv0); 476 rtld_die(); 477 } 478 479 /* 480 * For direct exec mode, argv[0] is the interpreter 481 * name, we must remove it and shift arguments left 482 * before invoking binary main. Since stack layout 483 * places environment pointers and aux vectors right 484 * after the terminating NULL, we must shift 485 * environment and aux as well. 486 */ 487 main_argc = argc - rtld_argc; 488 for (i = 0; i <= main_argc; i++) 489 argv[i] = argv[i + rtld_argc]; 490 *argcp -= rtld_argc; 491 environ = env = envp = argv + main_argc + 1; 492 do { 493 *envp = *(envp + rtld_argc); 494 envp++; 495 } while (*envp != NULL); 496 aux = auxp = (Elf_Auxinfo *)envp; 497 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 498 for (;; auxp++, auxpf++) { 499 *auxp = *auxpf; 500 if (auxp->a_type == AT_NULL) 501 break; 502 } 503 } else { 504 rtld_printf("no binary\n"); 505 rtld_die(); 506 } 507 } 508 } 509 510 ld_bind_now = getenv(_LD("BIND_NOW")); 511 512 /* 513 * If the process is tainted, then we un-set the dangerous environment 514 * variables. The process will be marked as tainted until setuid(2) 515 * is called. If any child process calls setuid(2) we do not want any 516 * future processes to honor the potentially un-safe variables. 517 */ 518 if (!trust) { 519 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 520 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 521 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 522 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 523 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 524 _rtld_error("environment corrupt; aborting"); 525 rtld_die(); 526 } 527 } 528 ld_debug = getenv(_LD("DEBUG")); 529 if (ld_bind_now == NULL) 530 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 531 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 532 libmap_override = getenv(_LD("LIBMAP")); 533 ld_library_path = getenv(_LD("LIBRARY_PATH")); 534 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 535 ld_preload = getenv(_LD("PRELOAD")); 536 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 537 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 538 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 539 if (library_path_rpath != NULL) { 540 if (library_path_rpath[0] == 'y' || 541 library_path_rpath[0] == 'Y' || 542 library_path_rpath[0] == '1') 543 ld_library_path_rpath = true; 544 else 545 ld_library_path_rpath = false; 546 } 547 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 548 (ld_library_path != NULL) || (ld_preload != NULL) || 549 (ld_elf_hints_path != NULL) || ld_loadfltr; 550 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 551 ld_utrace = getenv(_LD("UTRACE")); 552 553 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 554 ld_elf_hints_path = ld_elf_hints_default; 555 556 if (ld_debug != NULL && *ld_debug != '\0') 557 debug = 1; 558 dbg("%s is initialized, base address = %p", __progname, 559 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 560 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 561 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 562 563 dbg("initializing thread locks"); 564 lockdflt_init(); 565 566 /* 567 * Load the main program, or process its program header if it is 568 * already loaded. 569 */ 570 if (fd != -1) { /* Load the main program. */ 571 dbg("loading main program"); 572 obj_main = map_object(fd, argv0, NULL); 573 close(fd); 574 if (obj_main == NULL) 575 rtld_die(); 576 max_stack_flags = obj_main->stack_flags; 577 } else { /* Main program already loaded. */ 578 dbg("processing main program's program header"); 579 assert(aux_info[AT_PHDR] != NULL); 580 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 581 assert(aux_info[AT_PHNUM] != NULL); 582 phnum = aux_info[AT_PHNUM]->a_un.a_val; 583 assert(aux_info[AT_PHENT] != NULL); 584 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 585 assert(aux_info[AT_ENTRY] != NULL); 586 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 587 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 588 rtld_die(); 589 } 590 591 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 592 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 593 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 594 if (kexecpath[0] == '/') 595 obj_main->path = kexecpath; 596 else if (getcwd(buf, sizeof(buf)) == NULL || 597 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 598 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 599 obj_main->path = xstrdup(argv0); 600 else 601 obj_main->path = xstrdup(buf); 602 } else { 603 dbg("No AT_EXECPATH or direct exec"); 604 obj_main->path = xstrdup(argv0); 605 } 606 dbg("obj_main path %s", obj_main->path); 607 obj_main->mainprog = true; 608 609 if (aux_info[AT_STACKPROT] != NULL && 610 aux_info[AT_STACKPROT]->a_un.a_val != 0) 611 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 612 613 #ifndef COMPAT_32BIT 614 /* 615 * Get the actual dynamic linker pathname from the executable if 616 * possible. (It should always be possible.) That ensures that 617 * gdb will find the right dynamic linker even if a non-standard 618 * one is being used. 619 */ 620 if (obj_main->interp != NULL && 621 strcmp(obj_main->interp, obj_rtld.path) != 0) { 622 free(obj_rtld.path); 623 obj_rtld.path = xstrdup(obj_main->interp); 624 __progname = obj_rtld.path; 625 } 626 #endif 627 628 digest_dynamic(obj_main, 0); 629 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 630 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 631 obj_main->dynsymcount); 632 633 linkmap_add(obj_main); 634 linkmap_add(&obj_rtld); 635 636 /* Link the main program into the list of objects. */ 637 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 638 obj_count++; 639 obj_loads++; 640 641 /* Initialize a fake symbol for resolving undefined weak references. */ 642 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 643 sym_zero.st_shndx = SHN_UNDEF; 644 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 645 646 if (!libmap_disable) 647 libmap_disable = (bool)lm_init(libmap_override); 648 649 dbg("loading LD_PRELOAD libraries"); 650 if (load_preload_objects() == -1) 651 rtld_die(); 652 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 653 654 dbg("loading needed objects"); 655 if (load_needed_objects(obj_main, 0) == -1) 656 rtld_die(); 657 658 /* Make a list of all objects loaded at startup. */ 659 last_interposer = obj_main; 660 TAILQ_FOREACH(obj, &obj_list, next) { 661 if (obj->marker) 662 continue; 663 if (obj->z_interpose && obj != obj_main) { 664 objlist_put_after(&list_main, last_interposer, obj); 665 last_interposer = obj; 666 } else { 667 objlist_push_tail(&list_main, obj); 668 } 669 obj->refcount++; 670 } 671 672 dbg("checking for required versions"); 673 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 674 rtld_die(); 675 676 if (ld_tracing) { /* We're done */ 677 trace_loaded_objects(obj_main); 678 exit(0); 679 } 680 681 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 682 dump_relocations(obj_main); 683 exit (0); 684 } 685 686 /* 687 * Processing tls relocations requires having the tls offsets 688 * initialized. Prepare offsets before starting initial 689 * relocation processing. 690 */ 691 dbg("initializing initial thread local storage offsets"); 692 STAILQ_FOREACH(entry, &list_main, link) { 693 /* 694 * Allocate all the initial objects out of the static TLS 695 * block even if they didn't ask for it. 696 */ 697 allocate_tls_offset(entry->obj); 698 } 699 700 if (relocate_objects(obj_main, 701 ld_bind_now != NULL && *ld_bind_now != '\0', 702 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 703 rtld_die(); 704 705 dbg("doing copy relocations"); 706 if (do_copy_relocations(obj_main) == -1) 707 rtld_die(); 708 709 dbg("enforcing main obj relro"); 710 if (obj_enforce_relro(obj_main) == -1) 711 rtld_die(); 712 713 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 714 dump_relocations(obj_main); 715 exit (0); 716 } 717 718 /* 719 * Setup TLS for main thread. This must be done after the 720 * relocations are processed, since tls initialization section 721 * might be the subject for relocations. 722 */ 723 dbg("initializing initial thread local storage"); 724 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 725 726 dbg("initializing key program variables"); 727 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 728 set_program_var("environ", env); 729 set_program_var("__elf_aux_vector", aux); 730 731 /* Make a list of init functions to call. */ 732 objlist_init(&initlist); 733 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 734 preload_tail, &initlist); 735 736 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 737 738 map_stacks_exec(NULL); 739 ifunc_init(aux); 740 741 dbg("resolving ifuncs"); 742 if (resolve_objects_ifunc(obj_main, 743 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 744 NULL) == -1) 745 rtld_die(); 746 747 if (!obj_main->crt_no_init) { 748 /* 749 * Make sure we don't call the main program's init and fini 750 * functions for binaries linked with old crt1 which calls 751 * _init itself. 752 */ 753 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 754 obj_main->preinit_array = obj_main->init_array = 755 obj_main->fini_array = (Elf_Addr)NULL; 756 } 757 758 wlock_acquire(rtld_bind_lock, &lockstate); 759 if (obj_main->crt_no_init) 760 preinit_main(); 761 objlist_call_init(&initlist, &lockstate); 762 _r_debug_postinit(&obj_main->linkmap); 763 objlist_clear(&initlist); 764 dbg("loading filtees"); 765 TAILQ_FOREACH(obj, &obj_list, next) { 766 if (obj->marker) 767 continue; 768 if (ld_loadfltr || obj->z_loadfltr) 769 load_filtees(obj, 0, &lockstate); 770 } 771 lock_release(rtld_bind_lock, &lockstate); 772 773 dbg("transferring control to program entry point = %p", obj_main->entry); 774 775 /* Return the exit procedure and the program entry point. */ 776 *exit_proc = rtld_exit; 777 *objp = obj_main; 778 return (func_ptr_type) obj_main->entry; 779 } 780 781 void * 782 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 783 { 784 void *ptr; 785 Elf_Addr target; 786 787 ptr = (void *)make_function_pointer(def, obj); 788 target = call_ifunc_resolver(ptr); 789 return ((void *)target); 790 } 791 792 /* 793 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 794 * Changes to this function should be applied there as well. 795 */ 796 Elf_Addr 797 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 798 { 799 const Elf_Rel *rel; 800 const Elf_Sym *def; 801 const Obj_Entry *defobj; 802 Elf_Addr *where; 803 Elf_Addr target; 804 RtldLockState lockstate; 805 806 rlock_acquire(rtld_bind_lock, &lockstate); 807 if (sigsetjmp(lockstate.env, 0) != 0) 808 lock_upgrade(rtld_bind_lock, &lockstate); 809 if (obj->pltrel) 810 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 811 else 812 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 813 814 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 815 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 816 NULL, &lockstate); 817 if (def == NULL) 818 rtld_die(); 819 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 820 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 821 else 822 target = (Elf_Addr)(defobj->relocbase + def->st_value); 823 824 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 825 defobj->strtab + def->st_name, basename(obj->path), 826 (void *)target, basename(defobj->path)); 827 828 /* 829 * Write the new contents for the jmpslot. Note that depending on 830 * architecture, the value which we need to return back to the 831 * lazy binding trampoline may or may not be the target 832 * address. The value returned from reloc_jmpslot() is the value 833 * that the trampoline needs. 834 */ 835 target = reloc_jmpslot(where, target, defobj, obj, rel); 836 lock_release(rtld_bind_lock, &lockstate); 837 return target; 838 } 839 840 /* 841 * Error reporting function. Use it like printf. If formats the message 842 * into a buffer, and sets things up so that the next call to dlerror() 843 * will return the message. 844 */ 845 void 846 _rtld_error(const char *fmt, ...) 847 { 848 static char buf[512]; 849 va_list ap; 850 851 va_start(ap, fmt); 852 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 853 error_message = buf; 854 va_end(ap); 855 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 856 } 857 858 /* 859 * Return a dynamically-allocated copy of the current error message, if any. 860 */ 861 static char * 862 errmsg_save(void) 863 { 864 return error_message == NULL ? NULL : xstrdup(error_message); 865 } 866 867 /* 868 * Restore the current error message from a copy which was previously saved 869 * by errmsg_save(). The copy is freed. 870 */ 871 static void 872 errmsg_restore(char *saved_msg) 873 { 874 if (saved_msg == NULL) 875 error_message = NULL; 876 else { 877 _rtld_error("%s", saved_msg); 878 free(saved_msg); 879 } 880 } 881 882 static const char * 883 basename(const char *name) 884 { 885 const char *p = strrchr(name, '/'); 886 return p != NULL ? p + 1 : name; 887 } 888 889 static struct utsname uts; 890 891 static char * 892 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 893 const char *subst, bool may_free) 894 { 895 char *p, *p1, *res, *resp; 896 int subst_len, kw_len, subst_count, old_len, new_len; 897 898 kw_len = strlen(kw); 899 900 /* 901 * First, count the number of the keyword occurrences, to 902 * preallocate the final string. 903 */ 904 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 905 p1 = strstr(p, kw); 906 if (p1 == NULL) 907 break; 908 } 909 910 /* 911 * If the keyword is not found, just return. 912 * 913 * Return non-substituted string if resolution failed. We 914 * cannot do anything more reasonable, the failure mode of the 915 * caller is unresolved library anyway. 916 */ 917 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 918 return (may_free ? real : xstrdup(real)); 919 if (obj != NULL) 920 subst = obj->origin_path; 921 922 /* 923 * There is indeed something to substitute. Calculate the 924 * length of the resulting string, and allocate it. 925 */ 926 subst_len = strlen(subst); 927 old_len = strlen(real); 928 new_len = old_len + (subst_len - kw_len) * subst_count; 929 res = xmalloc(new_len + 1); 930 931 /* 932 * Now, execute the substitution loop. 933 */ 934 for (p = real, resp = res, *resp = '\0';;) { 935 p1 = strstr(p, kw); 936 if (p1 != NULL) { 937 /* Copy the prefix before keyword. */ 938 memcpy(resp, p, p1 - p); 939 resp += p1 - p; 940 /* Keyword replacement. */ 941 memcpy(resp, subst, subst_len); 942 resp += subst_len; 943 *resp = '\0'; 944 p = p1 + kw_len; 945 } else 946 break; 947 } 948 949 /* Copy to the end of string and finish. */ 950 strcat(resp, p); 951 if (may_free) 952 free(real); 953 return (res); 954 } 955 956 static char * 957 origin_subst(Obj_Entry *obj, char *real) 958 { 959 char *res1, *res2, *res3, *res4; 960 961 if (obj == NULL || !trust) 962 return (xstrdup(real)); 963 if (uts.sysname[0] == '\0') { 964 if (uname(&uts) != 0) { 965 _rtld_error("utsname failed: %d", errno); 966 return (NULL); 967 } 968 } 969 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 970 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 971 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 972 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 973 return (res4); 974 } 975 976 void 977 rtld_die(void) 978 { 979 const char *msg = dlerror(); 980 981 if (msg == NULL) 982 msg = "Fatal error"; 983 rtld_fdputstr(STDERR_FILENO, msg); 984 rtld_fdputchar(STDERR_FILENO, '\n'); 985 _exit(1); 986 } 987 988 /* 989 * Process a shared object's DYNAMIC section, and save the important 990 * information in its Obj_Entry structure. 991 */ 992 static void 993 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 994 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 995 { 996 const Elf_Dyn *dynp; 997 Needed_Entry **needed_tail = &obj->needed; 998 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 999 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1000 const Elf_Hashelt *hashtab; 1001 const Elf32_Word *hashval; 1002 Elf32_Word bkt, nmaskwords; 1003 int bloom_size32; 1004 int plttype = DT_REL; 1005 1006 *dyn_rpath = NULL; 1007 *dyn_soname = NULL; 1008 *dyn_runpath = NULL; 1009 1010 obj->bind_now = false; 1011 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1012 switch (dynp->d_tag) { 1013 1014 case DT_REL: 1015 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1016 break; 1017 1018 case DT_RELSZ: 1019 obj->relsize = dynp->d_un.d_val; 1020 break; 1021 1022 case DT_RELENT: 1023 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1024 break; 1025 1026 case DT_JMPREL: 1027 obj->pltrel = (const Elf_Rel *) 1028 (obj->relocbase + dynp->d_un.d_ptr); 1029 break; 1030 1031 case DT_PLTRELSZ: 1032 obj->pltrelsize = dynp->d_un.d_val; 1033 break; 1034 1035 case DT_RELA: 1036 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1037 break; 1038 1039 case DT_RELASZ: 1040 obj->relasize = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_RELAENT: 1044 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1045 break; 1046 1047 case DT_PLTREL: 1048 plttype = dynp->d_un.d_val; 1049 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1050 break; 1051 1052 case DT_SYMTAB: 1053 obj->symtab = (const Elf_Sym *) 1054 (obj->relocbase + dynp->d_un.d_ptr); 1055 break; 1056 1057 case DT_SYMENT: 1058 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1059 break; 1060 1061 case DT_STRTAB: 1062 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1063 break; 1064 1065 case DT_STRSZ: 1066 obj->strsize = dynp->d_un.d_val; 1067 break; 1068 1069 case DT_VERNEED: 1070 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1071 dynp->d_un.d_val); 1072 break; 1073 1074 case DT_VERNEEDNUM: 1075 obj->verneednum = dynp->d_un.d_val; 1076 break; 1077 1078 case DT_VERDEF: 1079 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1080 dynp->d_un.d_val); 1081 break; 1082 1083 case DT_VERDEFNUM: 1084 obj->verdefnum = dynp->d_un.d_val; 1085 break; 1086 1087 case DT_VERSYM: 1088 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1089 dynp->d_un.d_val); 1090 break; 1091 1092 case DT_HASH: 1093 { 1094 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1095 dynp->d_un.d_ptr); 1096 obj->nbuckets = hashtab[0]; 1097 obj->nchains = hashtab[1]; 1098 obj->buckets = hashtab + 2; 1099 obj->chains = obj->buckets + obj->nbuckets; 1100 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1101 obj->buckets != NULL; 1102 } 1103 break; 1104 1105 case DT_GNU_HASH: 1106 { 1107 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1108 dynp->d_un.d_ptr); 1109 obj->nbuckets_gnu = hashtab[0]; 1110 obj->symndx_gnu = hashtab[1]; 1111 nmaskwords = hashtab[2]; 1112 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1113 obj->maskwords_bm_gnu = nmaskwords - 1; 1114 obj->shift2_gnu = hashtab[3]; 1115 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1116 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1117 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1118 obj->symndx_gnu; 1119 /* Number of bitmask words is required to be power of 2 */ 1120 obj->valid_hash_gnu = powerof2(nmaskwords) && 1121 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1122 } 1123 break; 1124 1125 case DT_NEEDED: 1126 if (!obj->rtld) { 1127 Needed_Entry *nep = NEW(Needed_Entry); 1128 nep->name = dynp->d_un.d_val; 1129 nep->obj = NULL; 1130 nep->next = NULL; 1131 1132 *needed_tail = nep; 1133 needed_tail = &nep->next; 1134 } 1135 break; 1136 1137 case DT_FILTER: 1138 if (!obj->rtld) { 1139 Needed_Entry *nep = NEW(Needed_Entry); 1140 nep->name = dynp->d_un.d_val; 1141 nep->obj = NULL; 1142 nep->next = NULL; 1143 1144 *needed_filtees_tail = nep; 1145 needed_filtees_tail = &nep->next; 1146 } 1147 break; 1148 1149 case DT_AUXILIARY: 1150 if (!obj->rtld) { 1151 Needed_Entry *nep = NEW(Needed_Entry); 1152 nep->name = dynp->d_un.d_val; 1153 nep->obj = NULL; 1154 nep->next = NULL; 1155 1156 *needed_aux_filtees_tail = nep; 1157 needed_aux_filtees_tail = &nep->next; 1158 } 1159 break; 1160 1161 case DT_PLTGOT: 1162 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1163 break; 1164 1165 case DT_TEXTREL: 1166 obj->textrel = true; 1167 break; 1168 1169 case DT_SYMBOLIC: 1170 obj->symbolic = true; 1171 break; 1172 1173 case DT_RPATH: 1174 /* 1175 * We have to wait until later to process this, because we 1176 * might not have gotten the address of the string table yet. 1177 */ 1178 *dyn_rpath = dynp; 1179 break; 1180 1181 case DT_SONAME: 1182 *dyn_soname = dynp; 1183 break; 1184 1185 case DT_RUNPATH: 1186 *dyn_runpath = dynp; 1187 break; 1188 1189 case DT_INIT: 1190 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1191 break; 1192 1193 case DT_PREINIT_ARRAY: 1194 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1195 break; 1196 1197 case DT_PREINIT_ARRAYSZ: 1198 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1199 break; 1200 1201 case DT_INIT_ARRAY: 1202 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1203 break; 1204 1205 case DT_INIT_ARRAYSZ: 1206 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1207 break; 1208 1209 case DT_FINI: 1210 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1211 break; 1212 1213 case DT_FINI_ARRAY: 1214 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1215 break; 1216 1217 case DT_FINI_ARRAYSZ: 1218 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1219 break; 1220 1221 /* 1222 * Don't process DT_DEBUG on MIPS as the dynamic section 1223 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1224 */ 1225 1226 #ifndef __mips__ 1227 case DT_DEBUG: 1228 if (!early) 1229 dbg("Filling in DT_DEBUG entry"); 1230 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1231 break; 1232 #endif 1233 1234 case DT_FLAGS: 1235 if (dynp->d_un.d_val & DF_ORIGIN) 1236 obj->z_origin = true; 1237 if (dynp->d_un.d_val & DF_SYMBOLIC) 1238 obj->symbolic = true; 1239 if (dynp->d_un.d_val & DF_TEXTREL) 1240 obj->textrel = true; 1241 if (dynp->d_un.d_val & DF_BIND_NOW) 1242 obj->bind_now = true; 1243 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1244 ;*/ 1245 break; 1246 #ifdef __mips__ 1247 case DT_MIPS_LOCAL_GOTNO: 1248 obj->local_gotno = dynp->d_un.d_val; 1249 break; 1250 1251 case DT_MIPS_SYMTABNO: 1252 obj->symtabno = dynp->d_un.d_val; 1253 break; 1254 1255 case DT_MIPS_GOTSYM: 1256 obj->gotsym = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_MIPS_RLD_MAP: 1260 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1261 break; 1262 1263 case DT_MIPS_PLTGOT: 1264 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1265 dynp->d_un.d_ptr); 1266 break; 1267 1268 #endif 1269 1270 #ifdef __powerpc64__ 1271 case DT_PPC64_GLINK: 1272 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1273 break; 1274 #endif 1275 1276 case DT_FLAGS_1: 1277 if (dynp->d_un.d_val & DF_1_NOOPEN) 1278 obj->z_noopen = true; 1279 if (dynp->d_un.d_val & DF_1_ORIGIN) 1280 obj->z_origin = true; 1281 if (dynp->d_un.d_val & DF_1_GLOBAL) 1282 obj->z_global = true; 1283 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1284 obj->bind_now = true; 1285 if (dynp->d_un.d_val & DF_1_NODELETE) 1286 obj->z_nodelete = true; 1287 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1288 obj->z_loadfltr = true; 1289 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1290 obj->z_interpose = true; 1291 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1292 obj->z_nodeflib = true; 1293 break; 1294 1295 default: 1296 if (!early) { 1297 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1298 (long)dynp->d_tag); 1299 } 1300 break; 1301 } 1302 } 1303 1304 obj->traced = false; 1305 1306 if (plttype == DT_RELA) { 1307 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1308 obj->pltrel = NULL; 1309 obj->pltrelasize = obj->pltrelsize; 1310 obj->pltrelsize = 0; 1311 } 1312 1313 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1314 if (obj->valid_hash_sysv) 1315 obj->dynsymcount = obj->nchains; 1316 else if (obj->valid_hash_gnu) { 1317 obj->dynsymcount = 0; 1318 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1319 if (obj->buckets_gnu[bkt] == 0) 1320 continue; 1321 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1322 do 1323 obj->dynsymcount++; 1324 while ((*hashval++ & 1u) == 0); 1325 } 1326 obj->dynsymcount += obj->symndx_gnu; 1327 } 1328 } 1329 1330 static bool 1331 obj_resolve_origin(Obj_Entry *obj) 1332 { 1333 1334 if (obj->origin_path != NULL) 1335 return (true); 1336 obj->origin_path = xmalloc(PATH_MAX); 1337 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1338 } 1339 1340 static void 1341 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1342 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1343 { 1344 1345 if (obj->z_origin && !obj_resolve_origin(obj)) 1346 rtld_die(); 1347 1348 if (dyn_runpath != NULL) { 1349 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1350 obj->runpath = origin_subst(obj, obj->runpath); 1351 } else if (dyn_rpath != NULL) { 1352 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1353 obj->rpath = origin_subst(obj, obj->rpath); 1354 } 1355 if (dyn_soname != NULL) 1356 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1357 } 1358 1359 static void 1360 digest_dynamic(Obj_Entry *obj, int early) 1361 { 1362 const Elf_Dyn *dyn_rpath; 1363 const Elf_Dyn *dyn_soname; 1364 const Elf_Dyn *dyn_runpath; 1365 1366 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1367 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1368 } 1369 1370 /* 1371 * Process a shared object's program header. This is used only for the 1372 * main program, when the kernel has already loaded the main program 1373 * into memory before calling the dynamic linker. It creates and 1374 * returns an Obj_Entry structure. 1375 */ 1376 static Obj_Entry * 1377 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1378 { 1379 Obj_Entry *obj; 1380 const Elf_Phdr *phlimit = phdr + phnum; 1381 const Elf_Phdr *ph; 1382 Elf_Addr note_start, note_end; 1383 int nsegs = 0; 1384 1385 obj = obj_new(); 1386 for (ph = phdr; ph < phlimit; ph++) { 1387 if (ph->p_type != PT_PHDR) 1388 continue; 1389 1390 obj->phdr = phdr; 1391 obj->phsize = ph->p_memsz; 1392 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1393 break; 1394 } 1395 1396 obj->stack_flags = PF_X | PF_R | PF_W; 1397 1398 for (ph = phdr; ph < phlimit; ph++) { 1399 switch (ph->p_type) { 1400 1401 case PT_INTERP: 1402 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1403 break; 1404 1405 case PT_LOAD: 1406 if (nsegs == 0) { /* First load segment */ 1407 obj->vaddrbase = trunc_page(ph->p_vaddr); 1408 obj->mapbase = obj->vaddrbase + obj->relocbase; 1409 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1410 obj->vaddrbase; 1411 } else { /* Last load segment */ 1412 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1413 obj->vaddrbase; 1414 } 1415 nsegs++; 1416 break; 1417 1418 case PT_DYNAMIC: 1419 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1420 break; 1421 1422 case PT_TLS: 1423 obj->tlsindex = 1; 1424 obj->tlssize = ph->p_memsz; 1425 obj->tlsalign = ph->p_align; 1426 obj->tlsinitsize = ph->p_filesz; 1427 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1428 break; 1429 1430 case PT_GNU_STACK: 1431 obj->stack_flags = ph->p_flags; 1432 break; 1433 1434 case PT_GNU_RELRO: 1435 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1436 obj->relro_size = round_page(ph->p_memsz); 1437 break; 1438 1439 case PT_NOTE: 1440 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1441 note_end = note_start + ph->p_filesz; 1442 digest_notes(obj, note_start, note_end); 1443 break; 1444 } 1445 } 1446 if (nsegs < 1) { 1447 _rtld_error("%s: too few PT_LOAD segments", path); 1448 return NULL; 1449 } 1450 1451 obj->entry = entry; 1452 return obj; 1453 } 1454 1455 void 1456 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1457 { 1458 const Elf_Note *note; 1459 const char *note_name; 1460 uintptr_t p; 1461 1462 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1463 note = (const Elf_Note *)((const char *)(note + 1) + 1464 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1465 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1466 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1467 note->n_descsz != sizeof(int32_t)) 1468 continue; 1469 if (note->n_type != NT_FREEBSD_ABI_TAG && 1470 note->n_type != NT_FREEBSD_NOINIT_TAG) 1471 continue; 1472 note_name = (const char *)(note + 1); 1473 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1474 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1475 continue; 1476 switch (note->n_type) { 1477 case NT_FREEBSD_ABI_TAG: 1478 /* FreeBSD osrel note */ 1479 p = (uintptr_t)(note + 1); 1480 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1481 obj->osrel = *(const int32_t *)(p); 1482 dbg("note osrel %d", obj->osrel); 1483 break; 1484 case NT_FREEBSD_NOINIT_TAG: 1485 /* FreeBSD 'crt does not call init' note */ 1486 obj->crt_no_init = true; 1487 dbg("note crt_no_init"); 1488 break; 1489 } 1490 } 1491 } 1492 1493 static Obj_Entry * 1494 dlcheck(void *handle) 1495 { 1496 Obj_Entry *obj; 1497 1498 TAILQ_FOREACH(obj, &obj_list, next) { 1499 if (obj == (Obj_Entry *) handle) 1500 break; 1501 } 1502 1503 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1504 _rtld_error("Invalid shared object handle %p", handle); 1505 return NULL; 1506 } 1507 return obj; 1508 } 1509 1510 /* 1511 * If the given object is already in the donelist, return true. Otherwise 1512 * add the object to the list and return false. 1513 */ 1514 static bool 1515 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1516 { 1517 unsigned int i; 1518 1519 for (i = 0; i < dlp->num_used; i++) 1520 if (dlp->objs[i] == obj) 1521 return true; 1522 /* 1523 * Our donelist allocation should always be sufficient. But if 1524 * our threads locking isn't working properly, more shared objects 1525 * could have been loaded since we allocated the list. That should 1526 * never happen, but we'll handle it properly just in case it does. 1527 */ 1528 if (dlp->num_used < dlp->num_alloc) 1529 dlp->objs[dlp->num_used++] = obj; 1530 return false; 1531 } 1532 1533 /* 1534 * Hash function for symbol table lookup. Don't even think about changing 1535 * this. It is specified by the System V ABI. 1536 */ 1537 unsigned long 1538 elf_hash(const char *name) 1539 { 1540 const unsigned char *p = (const unsigned char *) name; 1541 unsigned long h = 0; 1542 unsigned long g; 1543 1544 while (*p != '\0') { 1545 h = (h << 4) + *p++; 1546 if ((g = h & 0xf0000000) != 0) 1547 h ^= g >> 24; 1548 h &= ~g; 1549 } 1550 return h; 1551 } 1552 1553 /* 1554 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1555 * unsigned in case it's implemented with a wider type. 1556 */ 1557 static uint32_t 1558 gnu_hash(const char *s) 1559 { 1560 uint32_t h; 1561 unsigned char c; 1562 1563 h = 5381; 1564 for (c = *s; c != '\0'; c = *++s) 1565 h = h * 33 + c; 1566 return (h & 0xffffffff); 1567 } 1568 1569 1570 /* 1571 * Find the library with the given name, and return its full pathname. 1572 * The returned string is dynamically allocated. Generates an error 1573 * message and returns NULL if the library cannot be found. 1574 * 1575 * If the second argument is non-NULL, then it refers to an already- 1576 * loaded shared object, whose library search path will be searched. 1577 * 1578 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1579 * descriptor (which is close-on-exec) will be passed out via the third 1580 * argument. 1581 * 1582 * The search order is: 1583 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1584 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1585 * LD_LIBRARY_PATH 1586 * DT_RUNPATH in the referencing file 1587 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1588 * from list) 1589 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1590 * 1591 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1592 */ 1593 static char * 1594 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1595 { 1596 char *pathname; 1597 char *name; 1598 bool nodeflib, objgiven; 1599 1600 objgiven = refobj != NULL; 1601 1602 if (libmap_disable || !objgiven || 1603 (name = lm_find(refobj->path, xname)) == NULL) 1604 name = (char *)xname; 1605 1606 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1607 if (name[0] != '/' && !trust) { 1608 _rtld_error("Absolute pathname required " 1609 "for shared object \"%s\"", name); 1610 return (NULL); 1611 } 1612 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1613 __DECONST(char *, name))); 1614 } 1615 1616 dbg(" Searching for \"%s\"", name); 1617 1618 /* 1619 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1620 * back to pre-conforming behaviour if user requested so with 1621 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1622 * nodeflib. 1623 */ 1624 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1625 pathname = search_library_path(name, ld_library_path, fdp); 1626 if (pathname != NULL) 1627 return (pathname); 1628 if (refobj != NULL) { 1629 pathname = search_library_path(name, refobj->rpath, fdp); 1630 if (pathname != NULL) 1631 return (pathname); 1632 } 1633 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1634 if (pathname != NULL) 1635 return (pathname); 1636 pathname = search_library_path(name, gethints(false), fdp); 1637 if (pathname != NULL) 1638 return (pathname); 1639 pathname = search_library_path(name, ld_standard_library_path, fdp); 1640 if (pathname != NULL) 1641 return (pathname); 1642 } else { 1643 nodeflib = objgiven ? refobj->z_nodeflib : false; 1644 if (objgiven) { 1645 pathname = search_library_path(name, refobj->rpath, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 } 1649 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1650 pathname = search_library_path(name, obj_main->rpath, fdp); 1651 if (pathname != NULL) 1652 return (pathname); 1653 } 1654 pathname = search_library_path(name, ld_library_path, fdp); 1655 if (pathname != NULL) 1656 return (pathname); 1657 if (objgiven) { 1658 pathname = search_library_path(name, refobj->runpath, fdp); 1659 if (pathname != NULL) 1660 return (pathname); 1661 } 1662 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1663 if (pathname != NULL) 1664 return (pathname); 1665 pathname = search_library_path(name, gethints(nodeflib), fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 if (objgiven && !nodeflib) { 1669 pathname = search_library_path(name, 1670 ld_standard_library_path, fdp); 1671 if (pathname != NULL) 1672 return (pathname); 1673 } 1674 } 1675 1676 if (objgiven && refobj->path != NULL) { 1677 _rtld_error("Shared object \"%s\" not found, " 1678 "required by \"%s\"", name, basename(refobj->path)); 1679 } else { 1680 _rtld_error("Shared object \"%s\" not found", name); 1681 } 1682 return (NULL); 1683 } 1684 1685 /* 1686 * Given a symbol number in a referencing object, find the corresponding 1687 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1688 * no definition was found. Returns a pointer to the Obj_Entry of the 1689 * defining object via the reference parameter DEFOBJ_OUT. 1690 */ 1691 const Elf_Sym * 1692 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1693 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1694 RtldLockState *lockstate) 1695 { 1696 const Elf_Sym *ref; 1697 const Elf_Sym *def; 1698 const Obj_Entry *defobj; 1699 const Ver_Entry *ve; 1700 SymLook req; 1701 const char *name; 1702 int res; 1703 1704 /* 1705 * If we have already found this symbol, get the information from 1706 * the cache. 1707 */ 1708 if (symnum >= refobj->dynsymcount) 1709 return NULL; /* Bad object */ 1710 if (cache != NULL && cache[symnum].sym != NULL) { 1711 *defobj_out = cache[symnum].obj; 1712 return cache[symnum].sym; 1713 } 1714 1715 ref = refobj->symtab + symnum; 1716 name = refobj->strtab + ref->st_name; 1717 def = NULL; 1718 defobj = NULL; 1719 ve = NULL; 1720 1721 /* 1722 * We don't have to do a full scale lookup if the symbol is local. 1723 * We know it will bind to the instance in this load module; to 1724 * which we already have a pointer (ie ref). By not doing a lookup, 1725 * we not only improve performance, but it also avoids unresolvable 1726 * symbols when local symbols are not in the hash table. This has 1727 * been seen with the ia64 toolchain. 1728 */ 1729 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1730 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1731 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1732 symnum); 1733 } 1734 symlook_init(&req, name); 1735 req.flags = flags; 1736 ve = req.ventry = fetch_ventry(refobj, symnum); 1737 req.lockstate = lockstate; 1738 res = symlook_default(&req, refobj); 1739 if (res == 0) { 1740 def = req.sym_out; 1741 defobj = req.defobj_out; 1742 } 1743 } else { 1744 def = ref; 1745 defobj = refobj; 1746 } 1747 1748 /* 1749 * If we found no definition and the reference is weak, treat the 1750 * symbol as having the value zero. 1751 */ 1752 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1753 def = &sym_zero; 1754 defobj = obj_main; 1755 } 1756 1757 if (def != NULL) { 1758 *defobj_out = defobj; 1759 /* Record the information in the cache to avoid subsequent lookups. */ 1760 if (cache != NULL) { 1761 cache[symnum].sym = def; 1762 cache[symnum].obj = defobj; 1763 } 1764 } else { 1765 if (refobj != &obj_rtld) 1766 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1767 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1768 } 1769 return def; 1770 } 1771 1772 /* 1773 * Return the search path from the ldconfig hints file, reading it if 1774 * necessary. If nostdlib is true, then the default search paths are 1775 * not added to result. 1776 * 1777 * Returns NULL if there are problems with the hints file, 1778 * or if the search path there is empty. 1779 */ 1780 static const char * 1781 gethints(bool nostdlib) 1782 { 1783 static char *hints, *filtered_path; 1784 static struct elfhints_hdr hdr; 1785 struct fill_search_info_args sargs, hargs; 1786 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1787 struct dl_serpath *SLPpath, *hintpath; 1788 char *p; 1789 struct stat hint_stat; 1790 unsigned int SLPndx, hintndx, fndx, fcount; 1791 int fd; 1792 size_t flen; 1793 uint32_t dl; 1794 bool skip; 1795 1796 /* First call, read the hints file */ 1797 if (hints == NULL) { 1798 /* Keep from trying again in case the hints file is bad. */ 1799 hints = ""; 1800 1801 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1802 return (NULL); 1803 1804 /* 1805 * Check of hdr.dirlistlen value against type limit 1806 * intends to pacify static analyzers. Further 1807 * paranoia leads to checks that dirlist is fully 1808 * contained in the file range. 1809 */ 1810 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1811 hdr.magic != ELFHINTS_MAGIC || 1812 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1813 fstat(fd, &hint_stat) == -1) { 1814 cleanup1: 1815 close(fd); 1816 hdr.dirlistlen = 0; 1817 return (NULL); 1818 } 1819 dl = hdr.strtab; 1820 if (dl + hdr.dirlist < dl) 1821 goto cleanup1; 1822 dl += hdr.dirlist; 1823 if (dl + hdr.dirlistlen < dl) 1824 goto cleanup1; 1825 dl += hdr.dirlistlen; 1826 if (dl > hint_stat.st_size) 1827 goto cleanup1; 1828 p = xmalloc(hdr.dirlistlen + 1); 1829 if (pread(fd, p, hdr.dirlistlen + 1, 1830 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1831 p[hdr.dirlistlen] != '\0') { 1832 free(p); 1833 goto cleanup1; 1834 } 1835 hints = p; 1836 close(fd); 1837 } 1838 1839 /* 1840 * If caller agreed to receive list which includes the default 1841 * paths, we are done. Otherwise, if we still did not 1842 * calculated filtered result, do it now. 1843 */ 1844 if (!nostdlib) 1845 return (hints[0] != '\0' ? hints : NULL); 1846 if (filtered_path != NULL) 1847 goto filt_ret; 1848 1849 /* 1850 * Obtain the list of all configured search paths, and the 1851 * list of the default paths. 1852 * 1853 * First estimate the size of the results. 1854 */ 1855 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1856 smeta.dls_cnt = 0; 1857 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1858 hmeta.dls_cnt = 0; 1859 1860 sargs.request = RTLD_DI_SERINFOSIZE; 1861 sargs.serinfo = &smeta; 1862 hargs.request = RTLD_DI_SERINFOSIZE; 1863 hargs.serinfo = &hmeta; 1864 1865 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1866 path_enumerate(hints, fill_search_info, &hargs); 1867 1868 SLPinfo = xmalloc(smeta.dls_size); 1869 hintinfo = xmalloc(hmeta.dls_size); 1870 1871 /* 1872 * Next fetch both sets of paths. 1873 */ 1874 sargs.request = RTLD_DI_SERINFO; 1875 sargs.serinfo = SLPinfo; 1876 sargs.serpath = &SLPinfo->dls_serpath[0]; 1877 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1878 1879 hargs.request = RTLD_DI_SERINFO; 1880 hargs.serinfo = hintinfo; 1881 hargs.serpath = &hintinfo->dls_serpath[0]; 1882 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1883 1884 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1885 path_enumerate(hints, fill_search_info, &hargs); 1886 1887 /* 1888 * Now calculate the difference between two sets, by excluding 1889 * standard paths from the full set. 1890 */ 1891 fndx = 0; 1892 fcount = 0; 1893 filtered_path = xmalloc(hdr.dirlistlen + 1); 1894 hintpath = &hintinfo->dls_serpath[0]; 1895 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1896 skip = false; 1897 SLPpath = &SLPinfo->dls_serpath[0]; 1898 /* 1899 * Check each standard path against current. 1900 */ 1901 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1902 /* matched, skip the path */ 1903 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1904 skip = true; 1905 break; 1906 } 1907 } 1908 if (skip) 1909 continue; 1910 /* 1911 * Not matched against any standard path, add the path 1912 * to result. Separate consequtive paths with ':'. 1913 */ 1914 if (fcount > 0) { 1915 filtered_path[fndx] = ':'; 1916 fndx++; 1917 } 1918 fcount++; 1919 flen = strlen(hintpath->dls_name); 1920 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1921 fndx += flen; 1922 } 1923 filtered_path[fndx] = '\0'; 1924 1925 free(SLPinfo); 1926 free(hintinfo); 1927 1928 filt_ret: 1929 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1930 } 1931 1932 static void 1933 init_dag(Obj_Entry *root) 1934 { 1935 const Needed_Entry *needed; 1936 const Objlist_Entry *elm; 1937 DoneList donelist; 1938 1939 if (root->dag_inited) 1940 return; 1941 donelist_init(&donelist); 1942 1943 /* Root object belongs to own DAG. */ 1944 objlist_push_tail(&root->dldags, root); 1945 objlist_push_tail(&root->dagmembers, root); 1946 donelist_check(&donelist, root); 1947 1948 /* 1949 * Add dependencies of root object to DAG in breadth order 1950 * by exploiting the fact that each new object get added 1951 * to the tail of the dagmembers list. 1952 */ 1953 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1954 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1955 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1956 continue; 1957 objlist_push_tail(&needed->obj->dldags, root); 1958 objlist_push_tail(&root->dagmembers, needed->obj); 1959 } 1960 } 1961 root->dag_inited = true; 1962 } 1963 1964 static void 1965 init_marker(Obj_Entry *marker) 1966 { 1967 1968 bzero(marker, sizeof(*marker)); 1969 marker->marker = true; 1970 } 1971 1972 Obj_Entry * 1973 globallist_curr(const Obj_Entry *obj) 1974 { 1975 1976 for (;;) { 1977 if (obj == NULL) 1978 return (NULL); 1979 if (!obj->marker) 1980 return (__DECONST(Obj_Entry *, obj)); 1981 obj = TAILQ_PREV(obj, obj_entry_q, next); 1982 } 1983 } 1984 1985 Obj_Entry * 1986 globallist_next(const Obj_Entry *obj) 1987 { 1988 1989 for (;;) { 1990 obj = TAILQ_NEXT(obj, next); 1991 if (obj == NULL) 1992 return (NULL); 1993 if (!obj->marker) 1994 return (__DECONST(Obj_Entry *, obj)); 1995 } 1996 } 1997 1998 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1999 static void 2000 hold_object(Obj_Entry *obj) 2001 { 2002 2003 obj->holdcount++; 2004 } 2005 2006 static void 2007 unhold_object(Obj_Entry *obj) 2008 { 2009 2010 assert(obj->holdcount > 0); 2011 if (--obj->holdcount == 0 && obj->unholdfree) 2012 release_object(obj); 2013 } 2014 2015 static void 2016 process_z(Obj_Entry *root) 2017 { 2018 const Objlist_Entry *elm; 2019 Obj_Entry *obj; 2020 2021 /* 2022 * Walk over object DAG and process every dependent object 2023 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2024 * to grow their own DAG. 2025 * 2026 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2027 * symlook_global() to work. 2028 * 2029 * For DF_1_NODELETE, the DAG should have its reference upped. 2030 */ 2031 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2032 obj = elm->obj; 2033 if (obj == NULL) 2034 continue; 2035 if (obj->z_nodelete && !obj->ref_nodel) { 2036 dbg("obj %s -z nodelete", obj->path); 2037 init_dag(obj); 2038 ref_dag(obj); 2039 obj->ref_nodel = true; 2040 } 2041 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2042 dbg("obj %s -z global", obj->path); 2043 objlist_push_tail(&list_global, obj); 2044 init_dag(obj); 2045 } 2046 } 2047 } 2048 /* 2049 * Initialize the dynamic linker. The argument is the address at which 2050 * the dynamic linker has been mapped into memory. The primary task of 2051 * this function is to relocate the dynamic linker. 2052 */ 2053 static void 2054 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2055 { 2056 Obj_Entry objtmp; /* Temporary rtld object */ 2057 const Elf_Ehdr *ehdr; 2058 const Elf_Dyn *dyn_rpath; 2059 const Elf_Dyn *dyn_soname; 2060 const Elf_Dyn *dyn_runpath; 2061 2062 #ifdef RTLD_INIT_PAGESIZES_EARLY 2063 /* The page size is required by the dynamic memory allocator. */ 2064 init_pagesizes(aux_info); 2065 #endif 2066 2067 /* 2068 * Conjure up an Obj_Entry structure for the dynamic linker. 2069 * 2070 * The "path" member can't be initialized yet because string constants 2071 * cannot yet be accessed. Below we will set it correctly. 2072 */ 2073 memset(&objtmp, 0, sizeof(objtmp)); 2074 objtmp.path = NULL; 2075 objtmp.rtld = true; 2076 objtmp.mapbase = mapbase; 2077 #ifdef PIC 2078 objtmp.relocbase = mapbase; 2079 #endif 2080 2081 objtmp.dynamic = rtld_dynamic(&objtmp); 2082 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2083 assert(objtmp.needed == NULL); 2084 #if !defined(__mips__) 2085 /* MIPS has a bogus DT_TEXTREL. */ 2086 assert(!objtmp.textrel); 2087 #endif 2088 /* 2089 * Temporarily put the dynamic linker entry into the object list, so 2090 * that symbols can be found. 2091 */ 2092 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2093 2094 ehdr = (Elf_Ehdr *)mapbase; 2095 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2096 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2097 2098 /* Initialize the object list. */ 2099 TAILQ_INIT(&obj_list); 2100 2101 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2102 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2103 2104 #ifndef RTLD_INIT_PAGESIZES_EARLY 2105 /* The page size is required by the dynamic memory allocator. */ 2106 init_pagesizes(aux_info); 2107 #endif 2108 2109 if (aux_info[AT_OSRELDATE] != NULL) 2110 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2111 2112 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2113 2114 /* Replace the path with a dynamically allocated copy. */ 2115 obj_rtld.path = xstrdup(ld_path_rtld); 2116 2117 r_debug.r_brk = r_debug_state; 2118 r_debug.r_state = RT_CONSISTENT; 2119 } 2120 2121 /* 2122 * Retrieve the array of supported page sizes. The kernel provides the page 2123 * sizes in increasing order. 2124 */ 2125 static void 2126 init_pagesizes(Elf_Auxinfo **aux_info) 2127 { 2128 static size_t psa[MAXPAGESIZES]; 2129 int mib[2]; 2130 size_t len, size; 2131 2132 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2133 NULL) { 2134 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2135 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2136 } else { 2137 len = 2; 2138 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2139 size = sizeof(psa); 2140 else { 2141 /* As a fallback, retrieve the base page size. */ 2142 size = sizeof(psa[0]); 2143 if (aux_info[AT_PAGESZ] != NULL) { 2144 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2145 goto psa_filled; 2146 } else { 2147 mib[0] = CTL_HW; 2148 mib[1] = HW_PAGESIZE; 2149 len = 2; 2150 } 2151 } 2152 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2153 _rtld_error("sysctl for hw.pagesize(s) failed"); 2154 rtld_die(); 2155 } 2156 psa_filled: 2157 pagesizes = psa; 2158 } 2159 npagesizes = size / sizeof(pagesizes[0]); 2160 /* Discard any invalid entries at the end of the array. */ 2161 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2162 npagesizes--; 2163 } 2164 2165 /* 2166 * Add the init functions from a needed object list (and its recursive 2167 * needed objects) to "list". This is not used directly; it is a helper 2168 * function for initlist_add_objects(). The write lock must be held 2169 * when this function is called. 2170 */ 2171 static void 2172 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2173 { 2174 /* Recursively process the successor needed objects. */ 2175 if (needed->next != NULL) 2176 initlist_add_neededs(needed->next, list); 2177 2178 /* Process the current needed object. */ 2179 if (needed->obj != NULL) 2180 initlist_add_objects(needed->obj, needed->obj, list); 2181 } 2182 2183 /* 2184 * Scan all of the DAGs rooted in the range of objects from "obj" to 2185 * "tail" and add their init functions to "list". This recurses over 2186 * the DAGs and ensure the proper init ordering such that each object's 2187 * needed libraries are initialized before the object itself. At the 2188 * same time, this function adds the objects to the global finalization 2189 * list "list_fini" in the opposite order. The write lock must be 2190 * held when this function is called. 2191 */ 2192 static void 2193 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2194 { 2195 Obj_Entry *nobj; 2196 2197 if (obj->init_scanned || obj->init_done) 2198 return; 2199 obj->init_scanned = true; 2200 2201 /* Recursively process the successor objects. */ 2202 nobj = globallist_next(obj); 2203 if (nobj != NULL && obj != tail) 2204 initlist_add_objects(nobj, tail, list); 2205 2206 /* Recursively process the needed objects. */ 2207 if (obj->needed != NULL) 2208 initlist_add_neededs(obj->needed, list); 2209 if (obj->needed_filtees != NULL) 2210 initlist_add_neededs(obj->needed_filtees, list); 2211 if (obj->needed_aux_filtees != NULL) 2212 initlist_add_neededs(obj->needed_aux_filtees, list); 2213 2214 /* Add the object to the init list. */ 2215 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2216 obj->init_array != (Elf_Addr)NULL) 2217 objlist_push_tail(list, obj); 2218 2219 /* Add the object to the global fini list in the reverse order. */ 2220 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2221 && !obj->on_fini_list) { 2222 objlist_push_head(&list_fini, obj); 2223 obj->on_fini_list = true; 2224 } 2225 } 2226 2227 #ifndef FPTR_TARGET 2228 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2229 #endif 2230 2231 static void 2232 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2233 { 2234 Needed_Entry *needed, *needed1; 2235 2236 for (needed = n; needed != NULL; needed = needed->next) { 2237 if (needed->obj != NULL) { 2238 dlclose_locked(needed->obj, lockstate); 2239 needed->obj = NULL; 2240 } 2241 } 2242 for (needed = n; needed != NULL; needed = needed1) { 2243 needed1 = needed->next; 2244 free(needed); 2245 } 2246 } 2247 2248 static void 2249 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2250 { 2251 2252 free_needed_filtees(obj->needed_filtees, lockstate); 2253 obj->needed_filtees = NULL; 2254 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2255 obj->needed_aux_filtees = NULL; 2256 obj->filtees_loaded = false; 2257 } 2258 2259 static void 2260 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2261 RtldLockState *lockstate) 2262 { 2263 2264 for (; needed != NULL; needed = needed->next) { 2265 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2266 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2267 RTLD_LOCAL, lockstate); 2268 } 2269 } 2270 2271 static void 2272 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2273 { 2274 2275 lock_restart_for_upgrade(lockstate); 2276 if (!obj->filtees_loaded) { 2277 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2278 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2279 obj->filtees_loaded = true; 2280 } 2281 } 2282 2283 static int 2284 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2285 { 2286 Obj_Entry *obj1; 2287 2288 for (; needed != NULL; needed = needed->next) { 2289 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2290 flags & ~RTLD_LO_NOLOAD); 2291 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2292 return (-1); 2293 } 2294 return (0); 2295 } 2296 2297 /* 2298 * Given a shared object, traverse its list of needed objects, and load 2299 * each of them. Returns 0 on success. Generates an error message and 2300 * returns -1 on failure. 2301 */ 2302 static int 2303 load_needed_objects(Obj_Entry *first, int flags) 2304 { 2305 Obj_Entry *obj; 2306 2307 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2308 if (obj->marker) 2309 continue; 2310 if (process_needed(obj, obj->needed, flags) == -1) 2311 return (-1); 2312 } 2313 return (0); 2314 } 2315 2316 static int 2317 load_preload_objects(void) 2318 { 2319 char *p = ld_preload; 2320 Obj_Entry *obj; 2321 static const char delim[] = " \t:;"; 2322 2323 if (p == NULL) 2324 return 0; 2325 2326 p += strspn(p, delim); 2327 while (*p != '\0') { 2328 size_t len = strcspn(p, delim); 2329 char savech; 2330 2331 savech = p[len]; 2332 p[len] = '\0'; 2333 obj = load_object(p, -1, NULL, 0); 2334 if (obj == NULL) 2335 return -1; /* XXX - cleanup */ 2336 obj->z_interpose = true; 2337 p[len] = savech; 2338 p += len; 2339 p += strspn(p, delim); 2340 } 2341 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2342 return 0; 2343 } 2344 2345 static const char * 2346 printable_path(const char *path) 2347 { 2348 2349 return (path == NULL ? "<unknown>" : path); 2350 } 2351 2352 /* 2353 * Load a shared object into memory, if it is not already loaded. The 2354 * object may be specified by name or by user-supplied file descriptor 2355 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2356 * duplicate is. 2357 * 2358 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2359 * on failure. 2360 */ 2361 static Obj_Entry * 2362 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2363 { 2364 Obj_Entry *obj; 2365 int fd; 2366 struct stat sb; 2367 char *path; 2368 2369 fd = -1; 2370 if (name != NULL) { 2371 TAILQ_FOREACH(obj, &obj_list, next) { 2372 if (obj->marker || obj->doomed) 2373 continue; 2374 if (object_match_name(obj, name)) 2375 return (obj); 2376 } 2377 2378 path = find_library(name, refobj, &fd); 2379 if (path == NULL) 2380 return (NULL); 2381 } else 2382 path = NULL; 2383 2384 if (fd >= 0) { 2385 /* 2386 * search_library_pathfds() opens a fresh file descriptor for the 2387 * library, so there is no need to dup(). 2388 */ 2389 } else if (fd_u == -1) { 2390 /* 2391 * If we didn't find a match by pathname, or the name is not 2392 * supplied, open the file and check again by device and inode. 2393 * This avoids false mismatches caused by multiple links or ".." 2394 * in pathnames. 2395 * 2396 * To avoid a race, we open the file and use fstat() rather than 2397 * using stat(). 2398 */ 2399 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2400 _rtld_error("Cannot open \"%s\"", path); 2401 free(path); 2402 return (NULL); 2403 } 2404 } else { 2405 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2406 if (fd == -1) { 2407 _rtld_error("Cannot dup fd"); 2408 free(path); 2409 return (NULL); 2410 } 2411 } 2412 if (fstat(fd, &sb) == -1) { 2413 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2414 close(fd); 2415 free(path); 2416 return NULL; 2417 } 2418 TAILQ_FOREACH(obj, &obj_list, next) { 2419 if (obj->marker || obj->doomed) 2420 continue; 2421 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2422 break; 2423 } 2424 if (obj != NULL && name != NULL) { 2425 object_add_name(obj, name); 2426 free(path); 2427 close(fd); 2428 return obj; 2429 } 2430 if (flags & RTLD_LO_NOLOAD) { 2431 free(path); 2432 close(fd); 2433 return (NULL); 2434 } 2435 2436 /* First use of this object, so we must map it in */ 2437 obj = do_load_object(fd, name, path, &sb, flags); 2438 if (obj == NULL) 2439 free(path); 2440 close(fd); 2441 2442 return obj; 2443 } 2444 2445 static Obj_Entry * 2446 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2447 int flags) 2448 { 2449 Obj_Entry *obj; 2450 struct statfs fs; 2451 2452 /* 2453 * but first, make sure that environment variables haven't been 2454 * used to circumvent the noexec flag on a filesystem. 2455 */ 2456 if (dangerous_ld_env) { 2457 if (fstatfs(fd, &fs) != 0) { 2458 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2459 return NULL; 2460 } 2461 if (fs.f_flags & MNT_NOEXEC) { 2462 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2463 return NULL; 2464 } 2465 } 2466 dbg("loading \"%s\"", printable_path(path)); 2467 obj = map_object(fd, printable_path(path), sbp); 2468 if (obj == NULL) 2469 return NULL; 2470 2471 /* 2472 * If DT_SONAME is present in the object, digest_dynamic2 already 2473 * added it to the object names. 2474 */ 2475 if (name != NULL) 2476 object_add_name(obj, name); 2477 obj->path = path; 2478 digest_dynamic(obj, 0); 2479 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2480 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2481 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2482 RTLD_LO_DLOPEN) { 2483 dbg("refusing to load non-loadable \"%s\"", obj->path); 2484 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2485 munmap(obj->mapbase, obj->mapsize); 2486 obj_free(obj); 2487 return (NULL); 2488 } 2489 2490 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2491 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2492 obj_count++; 2493 obj_loads++; 2494 linkmap_add(obj); /* for GDB & dlinfo() */ 2495 max_stack_flags |= obj->stack_flags; 2496 2497 dbg(" %p .. %p: %s", obj->mapbase, 2498 obj->mapbase + obj->mapsize - 1, obj->path); 2499 if (obj->textrel) 2500 dbg(" WARNING: %s has impure text", obj->path); 2501 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2502 obj->path); 2503 2504 return obj; 2505 } 2506 2507 static Obj_Entry * 2508 obj_from_addr(const void *addr) 2509 { 2510 Obj_Entry *obj; 2511 2512 TAILQ_FOREACH(obj, &obj_list, next) { 2513 if (obj->marker) 2514 continue; 2515 if (addr < (void *) obj->mapbase) 2516 continue; 2517 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2518 return obj; 2519 } 2520 return NULL; 2521 } 2522 2523 static void 2524 preinit_main(void) 2525 { 2526 Elf_Addr *preinit_addr; 2527 int index; 2528 2529 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2530 if (preinit_addr == NULL) 2531 return; 2532 2533 for (index = 0; index < obj_main->preinit_array_num; index++) { 2534 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2535 dbg("calling preinit function for %s at %p", obj_main->path, 2536 (void *)preinit_addr[index]); 2537 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2538 0, 0, obj_main->path); 2539 call_init_pointer(obj_main, preinit_addr[index]); 2540 } 2541 } 2542 } 2543 2544 /* 2545 * Call the finalization functions for each of the objects in "list" 2546 * belonging to the DAG of "root" and referenced once. If NULL "root" 2547 * is specified, every finalization function will be called regardless 2548 * of the reference count and the list elements won't be freed. All of 2549 * the objects are expected to have non-NULL fini functions. 2550 */ 2551 static void 2552 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2553 { 2554 Objlist_Entry *elm; 2555 char *saved_msg; 2556 Elf_Addr *fini_addr; 2557 int index; 2558 2559 assert(root == NULL || root->refcount == 1); 2560 2561 if (root != NULL) 2562 root->doomed = true; 2563 2564 /* 2565 * Preserve the current error message since a fini function might 2566 * call into the dynamic linker and overwrite it. 2567 */ 2568 saved_msg = errmsg_save(); 2569 do { 2570 STAILQ_FOREACH(elm, list, link) { 2571 if (root != NULL && (elm->obj->refcount != 1 || 2572 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2573 continue; 2574 /* Remove object from fini list to prevent recursive invocation. */ 2575 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2576 /* Ensure that new references cannot be acquired. */ 2577 elm->obj->doomed = true; 2578 2579 hold_object(elm->obj); 2580 lock_release(rtld_bind_lock, lockstate); 2581 /* 2582 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2583 * When this happens, DT_FINI_ARRAY is processed first. 2584 */ 2585 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2586 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2587 for (index = elm->obj->fini_array_num - 1; index >= 0; 2588 index--) { 2589 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2590 dbg("calling fini function for %s at %p", 2591 elm->obj->path, (void *)fini_addr[index]); 2592 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2593 (void *)fini_addr[index], 0, 0, elm->obj->path); 2594 call_initfini_pointer(elm->obj, fini_addr[index]); 2595 } 2596 } 2597 } 2598 if (elm->obj->fini != (Elf_Addr)NULL) { 2599 dbg("calling fini function for %s at %p", elm->obj->path, 2600 (void *)elm->obj->fini); 2601 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2602 0, 0, elm->obj->path); 2603 call_initfini_pointer(elm->obj, elm->obj->fini); 2604 } 2605 wlock_acquire(rtld_bind_lock, lockstate); 2606 unhold_object(elm->obj); 2607 /* No need to free anything if process is going down. */ 2608 if (root != NULL) 2609 free(elm); 2610 /* 2611 * We must restart the list traversal after every fini call 2612 * because a dlclose() call from the fini function or from 2613 * another thread might have modified the reference counts. 2614 */ 2615 break; 2616 } 2617 } while (elm != NULL); 2618 errmsg_restore(saved_msg); 2619 } 2620 2621 /* 2622 * Call the initialization functions for each of the objects in 2623 * "list". All of the objects are expected to have non-NULL init 2624 * functions. 2625 */ 2626 static void 2627 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2628 { 2629 Objlist_Entry *elm; 2630 Obj_Entry *obj; 2631 char *saved_msg; 2632 Elf_Addr *init_addr; 2633 int index; 2634 2635 /* 2636 * Clean init_scanned flag so that objects can be rechecked and 2637 * possibly initialized earlier if any of vectors called below 2638 * cause the change by using dlopen. 2639 */ 2640 TAILQ_FOREACH(obj, &obj_list, next) { 2641 if (obj->marker) 2642 continue; 2643 obj->init_scanned = false; 2644 } 2645 2646 /* 2647 * Preserve the current error message since an init function might 2648 * call into the dynamic linker and overwrite it. 2649 */ 2650 saved_msg = errmsg_save(); 2651 STAILQ_FOREACH(elm, list, link) { 2652 if (elm->obj->init_done) /* Initialized early. */ 2653 continue; 2654 /* 2655 * Race: other thread might try to use this object before current 2656 * one completes the initialization. Not much can be done here 2657 * without better locking. 2658 */ 2659 elm->obj->init_done = true; 2660 hold_object(elm->obj); 2661 lock_release(rtld_bind_lock, lockstate); 2662 2663 /* 2664 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2665 * When this happens, DT_INIT is processed first. 2666 */ 2667 if (elm->obj->init != (Elf_Addr)NULL) { 2668 dbg("calling init function for %s at %p", elm->obj->path, 2669 (void *)elm->obj->init); 2670 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2671 0, 0, elm->obj->path); 2672 call_initfini_pointer(elm->obj, elm->obj->init); 2673 } 2674 init_addr = (Elf_Addr *)elm->obj->init_array; 2675 if (init_addr != NULL) { 2676 for (index = 0; index < elm->obj->init_array_num; index++) { 2677 if (init_addr[index] != 0 && init_addr[index] != 1) { 2678 dbg("calling init function for %s at %p", elm->obj->path, 2679 (void *)init_addr[index]); 2680 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2681 (void *)init_addr[index], 0, 0, elm->obj->path); 2682 call_init_pointer(elm->obj, init_addr[index]); 2683 } 2684 } 2685 } 2686 wlock_acquire(rtld_bind_lock, lockstate); 2687 unhold_object(elm->obj); 2688 } 2689 errmsg_restore(saved_msg); 2690 } 2691 2692 static void 2693 objlist_clear(Objlist *list) 2694 { 2695 Objlist_Entry *elm; 2696 2697 while (!STAILQ_EMPTY(list)) { 2698 elm = STAILQ_FIRST(list); 2699 STAILQ_REMOVE_HEAD(list, link); 2700 free(elm); 2701 } 2702 } 2703 2704 static Objlist_Entry * 2705 objlist_find(Objlist *list, const Obj_Entry *obj) 2706 { 2707 Objlist_Entry *elm; 2708 2709 STAILQ_FOREACH(elm, list, link) 2710 if (elm->obj == obj) 2711 return elm; 2712 return NULL; 2713 } 2714 2715 static void 2716 objlist_init(Objlist *list) 2717 { 2718 STAILQ_INIT(list); 2719 } 2720 2721 static void 2722 objlist_push_head(Objlist *list, Obj_Entry *obj) 2723 { 2724 Objlist_Entry *elm; 2725 2726 elm = NEW(Objlist_Entry); 2727 elm->obj = obj; 2728 STAILQ_INSERT_HEAD(list, elm, link); 2729 } 2730 2731 static void 2732 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2733 { 2734 Objlist_Entry *elm; 2735 2736 elm = NEW(Objlist_Entry); 2737 elm->obj = obj; 2738 STAILQ_INSERT_TAIL(list, elm, link); 2739 } 2740 2741 static void 2742 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2743 { 2744 Objlist_Entry *elm, *listelm; 2745 2746 STAILQ_FOREACH(listelm, list, link) { 2747 if (listelm->obj == listobj) 2748 break; 2749 } 2750 elm = NEW(Objlist_Entry); 2751 elm->obj = obj; 2752 if (listelm != NULL) 2753 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2754 else 2755 STAILQ_INSERT_TAIL(list, elm, link); 2756 } 2757 2758 static void 2759 objlist_remove(Objlist *list, Obj_Entry *obj) 2760 { 2761 Objlist_Entry *elm; 2762 2763 if ((elm = objlist_find(list, obj)) != NULL) { 2764 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2765 free(elm); 2766 } 2767 } 2768 2769 /* 2770 * Relocate dag rooted in the specified object. 2771 * Returns 0 on success, or -1 on failure. 2772 */ 2773 2774 static int 2775 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2776 int flags, RtldLockState *lockstate) 2777 { 2778 Objlist_Entry *elm; 2779 int error; 2780 2781 error = 0; 2782 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2783 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2784 lockstate); 2785 if (error == -1) 2786 break; 2787 } 2788 return (error); 2789 } 2790 2791 /* 2792 * Prepare for, or clean after, relocating an object marked with 2793 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2794 * segments are remapped read-write. After relocations are done, the 2795 * segment's permissions are returned back to the modes specified in 2796 * the phdrs. If any relocation happened, or always for wired 2797 * program, COW is triggered. 2798 */ 2799 static int 2800 reloc_textrel_prot(Obj_Entry *obj, bool before) 2801 { 2802 const Elf_Phdr *ph; 2803 void *base; 2804 size_t l, sz; 2805 int prot; 2806 2807 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2808 l--, ph++) { 2809 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2810 continue; 2811 base = obj->relocbase + trunc_page(ph->p_vaddr); 2812 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2813 trunc_page(ph->p_vaddr); 2814 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2815 if (mprotect(base, sz, prot) == -1) { 2816 _rtld_error("%s: Cannot write-%sable text segment: %s", 2817 obj->path, before ? "en" : "dis", 2818 rtld_strerror(errno)); 2819 return (-1); 2820 } 2821 } 2822 return (0); 2823 } 2824 2825 /* 2826 * Relocate single object. 2827 * Returns 0 on success, or -1 on failure. 2828 */ 2829 static int 2830 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2831 int flags, RtldLockState *lockstate) 2832 { 2833 2834 if (obj->relocated) 2835 return (0); 2836 obj->relocated = true; 2837 if (obj != rtldobj) 2838 dbg("relocating \"%s\"", obj->path); 2839 2840 if (obj->symtab == NULL || obj->strtab == NULL || 2841 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2842 _rtld_error("%s: Shared object has no run-time symbol table", 2843 obj->path); 2844 return (-1); 2845 } 2846 2847 /* There are relocations to the write-protected text segment. */ 2848 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2849 return (-1); 2850 2851 /* Process the non-PLT non-IFUNC relocations. */ 2852 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2853 return (-1); 2854 2855 /* Re-protected the text segment. */ 2856 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2857 return (-1); 2858 2859 /* Set the special PLT or GOT entries. */ 2860 init_pltgot(obj); 2861 2862 /* Process the PLT relocations. */ 2863 if (reloc_plt(obj) == -1) 2864 return (-1); 2865 /* Relocate the jump slots if we are doing immediate binding. */ 2866 if (obj->bind_now || bind_now) 2867 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2868 return (-1); 2869 2870 /* 2871 * Process the non-PLT IFUNC relocations. The relocations are 2872 * processed in two phases, because IFUNC resolvers may 2873 * reference other symbols, which must be readily processed 2874 * before resolvers are called. 2875 */ 2876 if (obj->non_plt_gnu_ifunc && 2877 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2878 return (-1); 2879 2880 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2881 return (-1); 2882 2883 /* 2884 * Set up the magic number and version in the Obj_Entry. These 2885 * were checked in the crt1.o from the original ElfKit, so we 2886 * set them for backward compatibility. 2887 */ 2888 obj->magic = RTLD_MAGIC; 2889 obj->version = RTLD_VERSION; 2890 2891 return (0); 2892 } 2893 2894 /* 2895 * Relocate newly-loaded shared objects. The argument is a pointer to 2896 * the Obj_Entry for the first such object. All objects from the first 2897 * to the end of the list of objects are relocated. Returns 0 on success, 2898 * or -1 on failure. 2899 */ 2900 static int 2901 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2902 int flags, RtldLockState *lockstate) 2903 { 2904 Obj_Entry *obj; 2905 int error; 2906 2907 for (error = 0, obj = first; obj != NULL; 2908 obj = TAILQ_NEXT(obj, next)) { 2909 if (obj->marker) 2910 continue; 2911 error = relocate_object(obj, bind_now, rtldobj, flags, 2912 lockstate); 2913 if (error == -1) 2914 break; 2915 } 2916 return (error); 2917 } 2918 2919 /* 2920 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2921 * referencing STT_GNU_IFUNC symbols is postponed till the other 2922 * relocations are done. The indirect functions specified as 2923 * ifunc are allowed to call other symbols, so we need to have 2924 * objects relocated before asking for resolution from indirects. 2925 * 2926 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2927 * instead of the usual lazy handling of PLT slots. It is 2928 * consistent with how GNU does it. 2929 */ 2930 static int 2931 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2932 RtldLockState *lockstate) 2933 { 2934 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2935 return (-1); 2936 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2937 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2938 return (-1); 2939 return (0); 2940 } 2941 2942 static int 2943 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2944 RtldLockState *lockstate) 2945 { 2946 Obj_Entry *obj; 2947 2948 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2949 if (obj->marker) 2950 continue; 2951 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2952 return (-1); 2953 } 2954 return (0); 2955 } 2956 2957 static int 2958 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2959 RtldLockState *lockstate) 2960 { 2961 Objlist_Entry *elm; 2962 2963 STAILQ_FOREACH(elm, list, link) { 2964 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2965 lockstate) == -1) 2966 return (-1); 2967 } 2968 return (0); 2969 } 2970 2971 /* 2972 * Cleanup procedure. It will be called (by the atexit mechanism) just 2973 * before the process exits. 2974 */ 2975 static void 2976 rtld_exit(void) 2977 { 2978 RtldLockState lockstate; 2979 2980 wlock_acquire(rtld_bind_lock, &lockstate); 2981 dbg("rtld_exit()"); 2982 objlist_call_fini(&list_fini, NULL, &lockstate); 2983 /* No need to remove the items from the list, since we are exiting. */ 2984 if (!libmap_disable) 2985 lm_fini(); 2986 lock_release(rtld_bind_lock, &lockstate); 2987 } 2988 2989 /* 2990 * Iterate over a search path, translate each element, and invoke the 2991 * callback on the result. 2992 */ 2993 static void * 2994 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2995 { 2996 const char *trans; 2997 if (path == NULL) 2998 return (NULL); 2999 3000 path += strspn(path, ":;"); 3001 while (*path != '\0') { 3002 size_t len; 3003 char *res; 3004 3005 len = strcspn(path, ":;"); 3006 trans = lm_findn(NULL, path, len); 3007 if (trans) 3008 res = callback(trans, strlen(trans), arg); 3009 else 3010 res = callback(path, len, arg); 3011 3012 if (res != NULL) 3013 return (res); 3014 3015 path += len; 3016 path += strspn(path, ":;"); 3017 } 3018 3019 return (NULL); 3020 } 3021 3022 struct try_library_args { 3023 const char *name; 3024 size_t namelen; 3025 char *buffer; 3026 size_t buflen; 3027 int fd; 3028 }; 3029 3030 static void * 3031 try_library_path(const char *dir, size_t dirlen, void *param) 3032 { 3033 struct try_library_args *arg; 3034 int fd; 3035 3036 arg = param; 3037 if (*dir == '/' || trust) { 3038 char *pathname; 3039 3040 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3041 return (NULL); 3042 3043 pathname = arg->buffer; 3044 strncpy(pathname, dir, dirlen); 3045 pathname[dirlen] = '/'; 3046 strcpy(pathname + dirlen + 1, arg->name); 3047 3048 dbg(" Trying \"%s\"", pathname); 3049 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3050 if (fd >= 0) { 3051 dbg(" Opened \"%s\", fd %d", pathname, fd); 3052 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3053 strcpy(pathname, arg->buffer); 3054 arg->fd = fd; 3055 return (pathname); 3056 } else { 3057 dbg(" Failed to open \"%s\": %s", 3058 pathname, rtld_strerror(errno)); 3059 } 3060 } 3061 return (NULL); 3062 } 3063 3064 static char * 3065 search_library_path(const char *name, const char *path, int *fdp) 3066 { 3067 char *p; 3068 struct try_library_args arg; 3069 3070 if (path == NULL) 3071 return NULL; 3072 3073 arg.name = name; 3074 arg.namelen = strlen(name); 3075 arg.buffer = xmalloc(PATH_MAX); 3076 arg.buflen = PATH_MAX; 3077 arg.fd = -1; 3078 3079 p = path_enumerate(path, try_library_path, &arg); 3080 *fdp = arg.fd; 3081 3082 free(arg.buffer); 3083 3084 return (p); 3085 } 3086 3087 3088 /* 3089 * Finds the library with the given name using the directory descriptors 3090 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3091 * 3092 * Returns a freshly-opened close-on-exec file descriptor for the library, 3093 * or -1 if the library cannot be found. 3094 */ 3095 static char * 3096 search_library_pathfds(const char *name, const char *path, int *fdp) 3097 { 3098 char *envcopy, *fdstr, *found, *last_token; 3099 size_t len; 3100 int dirfd, fd; 3101 3102 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3103 3104 /* Don't load from user-specified libdirs into setuid binaries. */ 3105 if (!trust) 3106 return (NULL); 3107 3108 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3109 if (path == NULL) 3110 return (NULL); 3111 3112 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3113 if (name[0] == '/') { 3114 dbg("Absolute path (%s) passed to %s", name, __func__); 3115 return (NULL); 3116 } 3117 3118 /* 3119 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3120 * copy of the path, as strtok_r rewrites separator tokens 3121 * with '\0'. 3122 */ 3123 found = NULL; 3124 envcopy = xstrdup(path); 3125 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3126 fdstr = strtok_r(NULL, ":", &last_token)) { 3127 dirfd = parse_integer(fdstr); 3128 if (dirfd < 0) { 3129 _rtld_error("failed to parse directory FD: '%s'", 3130 fdstr); 3131 break; 3132 } 3133 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3134 if (fd >= 0) { 3135 *fdp = fd; 3136 len = strlen(fdstr) + strlen(name) + 3; 3137 found = xmalloc(len); 3138 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3139 _rtld_error("error generating '%d/%s'", 3140 dirfd, name); 3141 rtld_die(); 3142 } 3143 dbg("open('%s') => %d", found, fd); 3144 break; 3145 } 3146 } 3147 free(envcopy); 3148 3149 return (found); 3150 } 3151 3152 3153 int 3154 dlclose(void *handle) 3155 { 3156 RtldLockState lockstate; 3157 int error; 3158 3159 wlock_acquire(rtld_bind_lock, &lockstate); 3160 error = dlclose_locked(handle, &lockstate); 3161 lock_release(rtld_bind_lock, &lockstate); 3162 return (error); 3163 } 3164 3165 static int 3166 dlclose_locked(void *handle, RtldLockState *lockstate) 3167 { 3168 Obj_Entry *root; 3169 3170 root = dlcheck(handle); 3171 if (root == NULL) 3172 return -1; 3173 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3174 root->path); 3175 3176 /* Unreference the object and its dependencies. */ 3177 root->dl_refcount--; 3178 3179 if (root->refcount == 1) { 3180 /* 3181 * The object will be no longer referenced, so we must unload it. 3182 * First, call the fini functions. 3183 */ 3184 objlist_call_fini(&list_fini, root, lockstate); 3185 3186 unref_dag(root); 3187 3188 /* Finish cleaning up the newly-unreferenced objects. */ 3189 GDB_STATE(RT_DELETE,&root->linkmap); 3190 unload_object(root, lockstate); 3191 GDB_STATE(RT_CONSISTENT,NULL); 3192 } else 3193 unref_dag(root); 3194 3195 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3196 return 0; 3197 } 3198 3199 char * 3200 dlerror(void) 3201 { 3202 char *msg = error_message; 3203 error_message = NULL; 3204 return msg; 3205 } 3206 3207 /* 3208 * This function is deprecated and has no effect. 3209 */ 3210 void 3211 dllockinit(void *context, 3212 void *(*lock_create)(void *context), 3213 void (*rlock_acquire)(void *lock), 3214 void (*wlock_acquire)(void *lock), 3215 void (*lock_release)(void *lock), 3216 void (*lock_destroy)(void *lock), 3217 void (*context_destroy)(void *context)) 3218 { 3219 static void *cur_context; 3220 static void (*cur_context_destroy)(void *); 3221 3222 /* Just destroy the context from the previous call, if necessary. */ 3223 if (cur_context_destroy != NULL) 3224 cur_context_destroy(cur_context); 3225 cur_context = context; 3226 cur_context_destroy = context_destroy; 3227 } 3228 3229 void * 3230 dlopen(const char *name, int mode) 3231 { 3232 3233 return (rtld_dlopen(name, -1, mode)); 3234 } 3235 3236 void * 3237 fdlopen(int fd, int mode) 3238 { 3239 3240 return (rtld_dlopen(NULL, fd, mode)); 3241 } 3242 3243 static void * 3244 rtld_dlopen(const char *name, int fd, int mode) 3245 { 3246 RtldLockState lockstate; 3247 int lo_flags; 3248 3249 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3250 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3251 if (ld_tracing != NULL) { 3252 rlock_acquire(rtld_bind_lock, &lockstate); 3253 if (sigsetjmp(lockstate.env, 0) != 0) 3254 lock_upgrade(rtld_bind_lock, &lockstate); 3255 environ = (char **)*get_program_var_addr("environ", &lockstate); 3256 lock_release(rtld_bind_lock, &lockstate); 3257 } 3258 lo_flags = RTLD_LO_DLOPEN; 3259 if (mode & RTLD_NODELETE) 3260 lo_flags |= RTLD_LO_NODELETE; 3261 if (mode & RTLD_NOLOAD) 3262 lo_flags |= RTLD_LO_NOLOAD; 3263 if (ld_tracing != NULL) 3264 lo_flags |= RTLD_LO_TRACE; 3265 3266 return (dlopen_object(name, fd, obj_main, lo_flags, 3267 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3268 } 3269 3270 static void 3271 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3272 { 3273 3274 obj->dl_refcount--; 3275 unref_dag(obj); 3276 if (obj->refcount == 0) 3277 unload_object(obj, lockstate); 3278 } 3279 3280 static Obj_Entry * 3281 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3282 int mode, RtldLockState *lockstate) 3283 { 3284 Obj_Entry *old_obj_tail; 3285 Obj_Entry *obj; 3286 Objlist initlist; 3287 RtldLockState mlockstate; 3288 int result; 3289 3290 objlist_init(&initlist); 3291 3292 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3293 wlock_acquire(rtld_bind_lock, &mlockstate); 3294 lockstate = &mlockstate; 3295 } 3296 GDB_STATE(RT_ADD,NULL); 3297 3298 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3299 obj = NULL; 3300 if (name == NULL && fd == -1) { 3301 obj = obj_main; 3302 obj->refcount++; 3303 } else { 3304 obj = load_object(name, fd, refobj, lo_flags); 3305 } 3306 3307 if (obj) { 3308 obj->dl_refcount++; 3309 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3310 objlist_push_tail(&list_global, obj); 3311 if (globallist_next(old_obj_tail) != NULL) { 3312 /* We loaded something new. */ 3313 assert(globallist_next(old_obj_tail) == obj); 3314 result = load_needed_objects(obj, 3315 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3316 init_dag(obj); 3317 ref_dag(obj); 3318 if (result != -1) 3319 result = rtld_verify_versions(&obj->dagmembers); 3320 if (result != -1 && ld_tracing) 3321 goto trace; 3322 if (result == -1 || relocate_object_dag(obj, 3323 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3324 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3325 lockstate) == -1) { 3326 dlopen_cleanup(obj, lockstate); 3327 obj = NULL; 3328 } else if (lo_flags & RTLD_LO_EARLY) { 3329 /* 3330 * Do not call the init functions for early loaded 3331 * filtees. The image is still not initialized enough 3332 * for them to work. 3333 * 3334 * Our object is found by the global object list and 3335 * will be ordered among all init calls done right 3336 * before transferring control to main. 3337 */ 3338 } else { 3339 /* Make list of init functions to call. */ 3340 initlist_add_objects(obj, obj, &initlist); 3341 } 3342 /* 3343 * Process all no_delete or global objects here, given 3344 * them own DAGs to prevent their dependencies from being 3345 * unloaded. This has to be done after we have loaded all 3346 * of the dependencies, so that we do not miss any. 3347 */ 3348 if (obj != NULL) 3349 process_z(obj); 3350 } else { 3351 /* 3352 * Bump the reference counts for objects on this DAG. If 3353 * this is the first dlopen() call for the object that was 3354 * already loaded as a dependency, initialize the dag 3355 * starting at it. 3356 */ 3357 init_dag(obj); 3358 ref_dag(obj); 3359 3360 if ((lo_flags & RTLD_LO_TRACE) != 0) 3361 goto trace; 3362 } 3363 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3364 obj->z_nodelete) && !obj->ref_nodel) { 3365 dbg("obj %s nodelete", obj->path); 3366 ref_dag(obj); 3367 obj->z_nodelete = obj->ref_nodel = true; 3368 } 3369 } 3370 3371 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3372 name); 3373 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3374 3375 if (!(lo_flags & RTLD_LO_EARLY)) { 3376 map_stacks_exec(lockstate); 3377 } 3378 3379 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3380 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3381 lockstate) == -1) { 3382 objlist_clear(&initlist); 3383 dlopen_cleanup(obj, lockstate); 3384 if (lockstate == &mlockstate) 3385 lock_release(rtld_bind_lock, lockstate); 3386 return (NULL); 3387 } 3388 3389 if (!(lo_flags & RTLD_LO_EARLY)) { 3390 /* Call the init functions. */ 3391 objlist_call_init(&initlist, lockstate); 3392 } 3393 objlist_clear(&initlist); 3394 if (lockstate == &mlockstate) 3395 lock_release(rtld_bind_lock, lockstate); 3396 return obj; 3397 trace: 3398 trace_loaded_objects(obj); 3399 if (lockstate == &mlockstate) 3400 lock_release(rtld_bind_lock, lockstate); 3401 exit(0); 3402 } 3403 3404 static void * 3405 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3406 int flags) 3407 { 3408 DoneList donelist; 3409 const Obj_Entry *obj, *defobj; 3410 const Elf_Sym *def; 3411 SymLook req; 3412 RtldLockState lockstate; 3413 tls_index ti; 3414 void *sym; 3415 int res; 3416 3417 def = NULL; 3418 defobj = NULL; 3419 symlook_init(&req, name); 3420 req.ventry = ve; 3421 req.flags = flags | SYMLOOK_IN_PLT; 3422 req.lockstate = &lockstate; 3423 3424 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3425 rlock_acquire(rtld_bind_lock, &lockstate); 3426 if (sigsetjmp(lockstate.env, 0) != 0) 3427 lock_upgrade(rtld_bind_lock, &lockstate); 3428 if (handle == NULL || handle == RTLD_NEXT || 3429 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3430 3431 if ((obj = obj_from_addr(retaddr)) == NULL) { 3432 _rtld_error("Cannot determine caller's shared object"); 3433 lock_release(rtld_bind_lock, &lockstate); 3434 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3435 return NULL; 3436 } 3437 if (handle == NULL) { /* Just the caller's shared object. */ 3438 res = symlook_obj(&req, obj); 3439 if (res == 0) { 3440 def = req.sym_out; 3441 defobj = req.defobj_out; 3442 } 3443 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3444 handle == RTLD_SELF) { /* ... caller included */ 3445 if (handle == RTLD_NEXT) 3446 obj = globallist_next(obj); 3447 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3448 if (obj->marker) 3449 continue; 3450 res = symlook_obj(&req, obj); 3451 if (res == 0) { 3452 if (def == NULL || 3453 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3454 def = req.sym_out; 3455 defobj = req.defobj_out; 3456 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3457 break; 3458 } 3459 } 3460 } 3461 /* 3462 * Search the dynamic linker itself, and possibly resolve the 3463 * symbol from there. This is how the application links to 3464 * dynamic linker services such as dlopen. 3465 */ 3466 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3467 res = symlook_obj(&req, &obj_rtld); 3468 if (res == 0) { 3469 def = req.sym_out; 3470 defobj = req.defobj_out; 3471 } 3472 } 3473 } else { 3474 assert(handle == RTLD_DEFAULT); 3475 res = symlook_default(&req, obj); 3476 if (res == 0) { 3477 defobj = req.defobj_out; 3478 def = req.sym_out; 3479 } 3480 } 3481 } else { 3482 if ((obj = dlcheck(handle)) == NULL) { 3483 lock_release(rtld_bind_lock, &lockstate); 3484 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3485 return NULL; 3486 } 3487 3488 donelist_init(&donelist); 3489 if (obj->mainprog) { 3490 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3491 res = symlook_global(&req, &donelist); 3492 if (res == 0) { 3493 def = req.sym_out; 3494 defobj = req.defobj_out; 3495 } 3496 /* 3497 * Search the dynamic linker itself, and possibly resolve the 3498 * symbol from there. This is how the application links to 3499 * dynamic linker services such as dlopen. 3500 */ 3501 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3502 res = symlook_obj(&req, &obj_rtld); 3503 if (res == 0) { 3504 def = req.sym_out; 3505 defobj = req.defobj_out; 3506 } 3507 } 3508 } 3509 else { 3510 /* Search the whole DAG rooted at the given object. */ 3511 res = symlook_list(&req, &obj->dagmembers, &donelist); 3512 if (res == 0) { 3513 def = req.sym_out; 3514 defobj = req.defobj_out; 3515 } 3516 } 3517 } 3518 3519 if (def != NULL) { 3520 lock_release(rtld_bind_lock, &lockstate); 3521 3522 /* 3523 * The value required by the caller is derived from the value 3524 * of the symbol. this is simply the relocated value of the 3525 * symbol. 3526 */ 3527 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3528 sym = make_function_pointer(def, defobj); 3529 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3530 sym = rtld_resolve_ifunc(defobj, def); 3531 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3532 ti.ti_module = defobj->tlsindex; 3533 ti.ti_offset = def->st_value; 3534 sym = __tls_get_addr(&ti); 3535 } else 3536 sym = defobj->relocbase + def->st_value; 3537 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3538 return (sym); 3539 } 3540 3541 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3542 ve != NULL ? ve->name : ""); 3543 lock_release(rtld_bind_lock, &lockstate); 3544 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3545 return NULL; 3546 } 3547 3548 void * 3549 dlsym(void *handle, const char *name) 3550 { 3551 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3552 SYMLOOK_DLSYM); 3553 } 3554 3555 dlfunc_t 3556 dlfunc(void *handle, const char *name) 3557 { 3558 union { 3559 void *d; 3560 dlfunc_t f; 3561 } rv; 3562 3563 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3564 SYMLOOK_DLSYM); 3565 return (rv.f); 3566 } 3567 3568 void * 3569 dlvsym(void *handle, const char *name, const char *version) 3570 { 3571 Ver_Entry ventry; 3572 3573 ventry.name = version; 3574 ventry.file = NULL; 3575 ventry.hash = elf_hash(version); 3576 ventry.flags= 0; 3577 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3578 SYMLOOK_DLSYM); 3579 } 3580 3581 int 3582 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3583 { 3584 const Obj_Entry *obj; 3585 RtldLockState lockstate; 3586 3587 rlock_acquire(rtld_bind_lock, &lockstate); 3588 obj = obj_from_addr(addr); 3589 if (obj == NULL) { 3590 _rtld_error("No shared object contains address"); 3591 lock_release(rtld_bind_lock, &lockstate); 3592 return (0); 3593 } 3594 rtld_fill_dl_phdr_info(obj, phdr_info); 3595 lock_release(rtld_bind_lock, &lockstate); 3596 return (1); 3597 } 3598 3599 int 3600 dladdr(const void *addr, Dl_info *info) 3601 { 3602 const Obj_Entry *obj; 3603 const Elf_Sym *def; 3604 void *symbol_addr; 3605 unsigned long symoffset; 3606 RtldLockState lockstate; 3607 3608 rlock_acquire(rtld_bind_lock, &lockstate); 3609 obj = obj_from_addr(addr); 3610 if (obj == NULL) { 3611 _rtld_error("No shared object contains address"); 3612 lock_release(rtld_bind_lock, &lockstate); 3613 return 0; 3614 } 3615 info->dli_fname = obj->path; 3616 info->dli_fbase = obj->mapbase; 3617 info->dli_saddr = (void *)0; 3618 info->dli_sname = NULL; 3619 3620 /* 3621 * Walk the symbol list looking for the symbol whose address is 3622 * closest to the address sent in. 3623 */ 3624 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3625 def = obj->symtab + symoffset; 3626 3627 /* 3628 * For skip the symbol if st_shndx is either SHN_UNDEF or 3629 * SHN_COMMON. 3630 */ 3631 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3632 continue; 3633 3634 /* 3635 * If the symbol is greater than the specified address, or if it 3636 * is further away from addr than the current nearest symbol, 3637 * then reject it. 3638 */ 3639 symbol_addr = obj->relocbase + def->st_value; 3640 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3641 continue; 3642 3643 /* Update our idea of the nearest symbol. */ 3644 info->dli_sname = obj->strtab + def->st_name; 3645 info->dli_saddr = symbol_addr; 3646 3647 /* Exact match? */ 3648 if (info->dli_saddr == addr) 3649 break; 3650 } 3651 lock_release(rtld_bind_lock, &lockstate); 3652 return 1; 3653 } 3654 3655 int 3656 dlinfo(void *handle, int request, void *p) 3657 { 3658 const Obj_Entry *obj; 3659 RtldLockState lockstate; 3660 int error; 3661 3662 rlock_acquire(rtld_bind_lock, &lockstate); 3663 3664 if (handle == NULL || handle == RTLD_SELF) { 3665 void *retaddr; 3666 3667 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3668 if ((obj = obj_from_addr(retaddr)) == NULL) 3669 _rtld_error("Cannot determine caller's shared object"); 3670 } else 3671 obj = dlcheck(handle); 3672 3673 if (obj == NULL) { 3674 lock_release(rtld_bind_lock, &lockstate); 3675 return (-1); 3676 } 3677 3678 error = 0; 3679 switch (request) { 3680 case RTLD_DI_LINKMAP: 3681 *((struct link_map const **)p) = &obj->linkmap; 3682 break; 3683 case RTLD_DI_ORIGIN: 3684 error = rtld_dirname(obj->path, p); 3685 break; 3686 3687 case RTLD_DI_SERINFOSIZE: 3688 case RTLD_DI_SERINFO: 3689 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3690 break; 3691 3692 default: 3693 _rtld_error("Invalid request %d passed to dlinfo()", request); 3694 error = -1; 3695 } 3696 3697 lock_release(rtld_bind_lock, &lockstate); 3698 3699 return (error); 3700 } 3701 3702 static void 3703 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3704 { 3705 3706 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3707 phdr_info->dlpi_name = obj->path; 3708 phdr_info->dlpi_phdr = obj->phdr; 3709 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3710 phdr_info->dlpi_tls_modid = obj->tlsindex; 3711 phdr_info->dlpi_tls_data = obj->tlsinit; 3712 phdr_info->dlpi_adds = obj_loads; 3713 phdr_info->dlpi_subs = obj_loads - obj_count; 3714 } 3715 3716 int 3717 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3718 { 3719 struct dl_phdr_info phdr_info; 3720 Obj_Entry *obj, marker; 3721 RtldLockState bind_lockstate, phdr_lockstate; 3722 int error; 3723 3724 init_marker(&marker); 3725 error = 0; 3726 3727 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3728 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3729 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3730 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3731 rtld_fill_dl_phdr_info(obj, &phdr_info); 3732 hold_object(obj); 3733 lock_release(rtld_bind_lock, &bind_lockstate); 3734 3735 error = callback(&phdr_info, sizeof phdr_info, param); 3736 3737 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3738 unhold_object(obj); 3739 obj = globallist_next(&marker); 3740 TAILQ_REMOVE(&obj_list, &marker, next); 3741 if (error != 0) { 3742 lock_release(rtld_bind_lock, &bind_lockstate); 3743 lock_release(rtld_phdr_lock, &phdr_lockstate); 3744 return (error); 3745 } 3746 } 3747 3748 if (error == 0) { 3749 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3750 lock_release(rtld_bind_lock, &bind_lockstate); 3751 error = callback(&phdr_info, sizeof(phdr_info), param); 3752 } 3753 lock_release(rtld_phdr_lock, &phdr_lockstate); 3754 return (error); 3755 } 3756 3757 static void * 3758 fill_search_info(const char *dir, size_t dirlen, void *param) 3759 { 3760 struct fill_search_info_args *arg; 3761 3762 arg = param; 3763 3764 if (arg->request == RTLD_DI_SERINFOSIZE) { 3765 arg->serinfo->dls_cnt ++; 3766 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3767 } else { 3768 struct dl_serpath *s_entry; 3769 3770 s_entry = arg->serpath; 3771 s_entry->dls_name = arg->strspace; 3772 s_entry->dls_flags = arg->flags; 3773 3774 strncpy(arg->strspace, dir, dirlen); 3775 arg->strspace[dirlen] = '\0'; 3776 3777 arg->strspace += dirlen + 1; 3778 arg->serpath++; 3779 } 3780 3781 return (NULL); 3782 } 3783 3784 static int 3785 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3786 { 3787 struct dl_serinfo _info; 3788 struct fill_search_info_args args; 3789 3790 args.request = RTLD_DI_SERINFOSIZE; 3791 args.serinfo = &_info; 3792 3793 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3794 _info.dls_cnt = 0; 3795 3796 path_enumerate(obj->rpath, fill_search_info, &args); 3797 path_enumerate(ld_library_path, fill_search_info, &args); 3798 path_enumerate(obj->runpath, fill_search_info, &args); 3799 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3800 if (!obj->z_nodeflib) 3801 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3802 3803 3804 if (request == RTLD_DI_SERINFOSIZE) { 3805 info->dls_size = _info.dls_size; 3806 info->dls_cnt = _info.dls_cnt; 3807 return (0); 3808 } 3809 3810 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3811 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3812 return (-1); 3813 } 3814 3815 args.request = RTLD_DI_SERINFO; 3816 args.serinfo = info; 3817 args.serpath = &info->dls_serpath[0]; 3818 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3819 3820 args.flags = LA_SER_RUNPATH; 3821 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3822 return (-1); 3823 3824 args.flags = LA_SER_LIBPATH; 3825 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3826 return (-1); 3827 3828 args.flags = LA_SER_RUNPATH; 3829 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3830 return (-1); 3831 3832 args.flags = LA_SER_CONFIG; 3833 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3834 != NULL) 3835 return (-1); 3836 3837 args.flags = LA_SER_DEFAULT; 3838 if (!obj->z_nodeflib && 3839 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3840 return (-1); 3841 return (0); 3842 } 3843 3844 static int 3845 rtld_dirname(const char *path, char *bname) 3846 { 3847 const char *endp; 3848 3849 /* Empty or NULL string gets treated as "." */ 3850 if (path == NULL || *path == '\0') { 3851 bname[0] = '.'; 3852 bname[1] = '\0'; 3853 return (0); 3854 } 3855 3856 /* Strip trailing slashes */ 3857 endp = path + strlen(path) - 1; 3858 while (endp > path && *endp == '/') 3859 endp--; 3860 3861 /* Find the start of the dir */ 3862 while (endp > path && *endp != '/') 3863 endp--; 3864 3865 /* Either the dir is "/" or there are no slashes */ 3866 if (endp == path) { 3867 bname[0] = *endp == '/' ? '/' : '.'; 3868 bname[1] = '\0'; 3869 return (0); 3870 } else { 3871 do { 3872 endp--; 3873 } while (endp > path && *endp == '/'); 3874 } 3875 3876 if (endp - path + 2 > PATH_MAX) 3877 { 3878 _rtld_error("Filename is too long: %s", path); 3879 return(-1); 3880 } 3881 3882 strncpy(bname, path, endp - path + 1); 3883 bname[endp - path + 1] = '\0'; 3884 return (0); 3885 } 3886 3887 static int 3888 rtld_dirname_abs(const char *path, char *base) 3889 { 3890 char *last; 3891 3892 if (realpath(path, base) == NULL) 3893 return (-1); 3894 dbg("%s -> %s", path, base); 3895 last = strrchr(base, '/'); 3896 if (last == NULL) 3897 return (-1); 3898 if (last != base) 3899 *last = '\0'; 3900 return (0); 3901 } 3902 3903 static void 3904 linkmap_add(Obj_Entry *obj) 3905 { 3906 struct link_map *l = &obj->linkmap; 3907 struct link_map *prev; 3908 3909 obj->linkmap.l_name = obj->path; 3910 obj->linkmap.l_addr = obj->mapbase; 3911 obj->linkmap.l_ld = obj->dynamic; 3912 #ifdef __mips__ 3913 /* GDB needs load offset on MIPS to use the symbols */ 3914 obj->linkmap.l_offs = obj->relocbase; 3915 #endif 3916 3917 if (r_debug.r_map == NULL) { 3918 r_debug.r_map = l; 3919 return; 3920 } 3921 3922 /* 3923 * Scan to the end of the list, but not past the entry for the 3924 * dynamic linker, which we want to keep at the very end. 3925 */ 3926 for (prev = r_debug.r_map; 3927 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3928 prev = prev->l_next) 3929 ; 3930 3931 /* Link in the new entry. */ 3932 l->l_prev = prev; 3933 l->l_next = prev->l_next; 3934 if (l->l_next != NULL) 3935 l->l_next->l_prev = l; 3936 prev->l_next = l; 3937 } 3938 3939 static void 3940 linkmap_delete(Obj_Entry *obj) 3941 { 3942 struct link_map *l = &obj->linkmap; 3943 3944 if (l->l_prev == NULL) { 3945 if ((r_debug.r_map = l->l_next) != NULL) 3946 l->l_next->l_prev = NULL; 3947 return; 3948 } 3949 3950 if ((l->l_prev->l_next = l->l_next) != NULL) 3951 l->l_next->l_prev = l->l_prev; 3952 } 3953 3954 /* 3955 * Function for the debugger to set a breakpoint on to gain control. 3956 * 3957 * The two parameters allow the debugger to easily find and determine 3958 * what the runtime loader is doing and to whom it is doing it. 3959 * 3960 * When the loadhook trap is hit (r_debug_state, set at program 3961 * initialization), the arguments can be found on the stack: 3962 * 3963 * +8 struct link_map *m 3964 * +4 struct r_debug *rd 3965 * +0 RetAddr 3966 */ 3967 void 3968 r_debug_state(struct r_debug* rd, struct link_map *m) 3969 { 3970 /* 3971 * The following is a hack to force the compiler to emit calls to 3972 * this function, even when optimizing. If the function is empty, 3973 * the compiler is not obliged to emit any code for calls to it, 3974 * even when marked __noinline. However, gdb depends on those 3975 * calls being made. 3976 */ 3977 __compiler_membar(); 3978 } 3979 3980 /* 3981 * A function called after init routines have completed. This can be used to 3982 * break before a program's entry routine is called, and can be used when 3983 * main is not available in the symbol table. 3984 */ 3985 void 3986 _r_debug_postinit(struct link_map *m) 3987 { 3988 3989 /* See r_debug_state(). */ 3990 __compiler_membar(); 3991 } 3992 3993 static void 3994 release_object(Obj_Entry *obj) 3995 { 3996 3997 if (obj->holdcount > 0) { 3998 obj->unholdfree = true; 3999 return; 4000 } 4001 munmap(obj->mapbase, obj->mapsize); 4002 linkmap_delete(obj); 4003 obj_free(obj); 4004 } 4005 4006 /* 4007 * Get address of the pointer variable in the main program. 4008 * Prefer non-weak symbol over the weak one. 4009 */ 4010 static const void ** 4011 get_program_var_addr(const char *name, RtldLockState *lockstate) 4012 { 4013 SymLook req; 4014 DoneList donelist; 4015 4016 symlook_init(&req, name); 4017 req.lockstate = lockstate; 4018 donelist_init(&donelist); 4019 if (symlook_global(&req, &donelist) != 0) 4020 return (NULL); 4021 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4022 return ((const void **)make_function_pointer(req.sym_out, 4023 req.defobj_out)); 4024 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4025 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4026 else 4027 return ((const void **)(req.defobj_out->relocbase + 4028 req.sym_out->st_value)); 4029 } 4030 4031 /* 4032 * Set a pointer variable in the main program to the given value. This 4033 * is used to set key variables such as "environ" before any of the 4034 * init functions are called. 4035 */ 4036 static void 4037 set_program_var(const char *name, const void *value) 4038 { 4039 const void **addr; 4040 4041 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4042 dbg("\"%s\": *%p <-- %p", name, addr, value); 4043 *addr = value; 4044 } 4045 } 4046 4047 /* 4048 * Search the global objects, including dependencies and main object, 4049 * for the given symbol. 4050 */ 4051 static int 4052 symlook_global(SymLook *req, DoneList *donelist) 4053 { 4054 SymLook req1; 4055 const Objlist_Entry *elm; 4056 int res; 4057 4058 symlook_init_from_req(&req1, req); 4059 4060 /* Search all objects loaded at program start up. */ 4061 if (req->defobj_out == NULL || 4062 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4063 res = symlook_list(&req1, &list_main, donelist); 4064 if (res == 0 && (req->defobj_out == NULL || 4065 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4066 req->sym_out = req1.sym_out; 4067 req->defobj_out = req1.defobj_out; 4068 assert(req->defobj_out != NULL); 4069 } 4070 } 4071 4072 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4073 STAILQ_FOREACH(elm, &list_global, link) { 4074 if (req->defobj_out != NULL && 4075 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4076 break; 4077 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4078 if (res == 0 && (req->defobj_out == NULL || 4079 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4080 req->sym_out = req1.sym_out; 4081 req->defobj_out = req1.defobj_out; 4082 assert(req->defobj_out != NULL); 4083 } 4084 } 4085 4086 return (req->sym_out != NULL ? 0 : ESRCH); 4087 } 4088 4089 /* 4090 * Given a symbol name in a referencing object, find the corresponding 4091 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4092 * no definition was found. Returns a pointer to the Obj_Entry of the 4093 * defining object via the reference parameter DEFOBJ_OUT. 4094 */ 4095 static int 4096 symlook_default(SymLook *req, const Obj_Entry *refobj) 4097 { 4098 DoneList donelist; 4099 const Objlist_Entry *elm; 4100 SymLook req1; 4101 int res; 4102 4103 donelist_init(&donelist); 4104 symlook_init_from_req(&req1, req); 4105 4106 /* 4107 * Look first in the referencing object if linked symbolically, 4108 * and similarly handle protected symbols. 4109 */ 4110 res = symlook_obj(&req1, refobj); 4111 if (res == 0 && (refobj->symbolic || 4112 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4113 req->sym_out = req1.sym_out; 4114 req->defobj_out = req1.defobj_out; 4115 assert(req->defobj_out != NULL); 4116 } 4117 if (refobj->symbolic || req->defobj_out != NULL) 4118 donelist_check(&donelist, refobj); 4119 4120 symlook_global(req, &donelist); 4121 4122 /* Search all dlopened DAGs containing the referencing object. */ 4123 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4124 if (req->sym_out != NULL && 4125 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4126 break; 4127 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4128 if (res == 0 && (req->sym_out == NULL || 4129 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4130 req->sym_out = req1.sym_out; 4131 req->defobj_out = req1.defobj_out; 4132 assert(req->defobj_out != NULL); 4133 } 4134 } 4135 4136 /* 4137 * Search the dynamic linker itself, and possibly resolve the 4138 * symbol from there. This is how the application links to 4139 * dynamic linker services such as dlopen. 4140 */ 4141 if (req->sym_out == NULL || 4142 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4143 res = symlook_obj(&req1, &obj_rtld); 4144 if (res == 0) { 4145 req->sym_out = req1.sym_out; 4146 req->defobj_out = req1.defobj_out; 4147 assert(req->defobj_out != NULL); 4148 } 4149 } 4150 4151 return (req->sym_out != NULL ? 0 : ESRCH); 4152 } 4153 4154 static int 4155 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4156 { 4157 const Elf_Sym *def; 4158 const Obj_Entry *defobj; 4159 const Objlist_Entry *elm; 4160 SymLook req1; 4161 int res; 4162 4163 def = NULL; 4164 defobj = NULL; 4165 STAILQ_FOREACH(elm, objlist, link) { 4166 if (donelist_check(dlp, elm->obj)) 4167 continue; 4168 symlook_init_from_req(&req1, req); 4169 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4170 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4171 def = req1.sym_out; 4172 defobj = req1.defobj_out; 4173 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4174 break; 4175 } 4176 } 4177 } 4178 if (def != NULL) { 4179 req->sym_out = def; 4180 req->defobj_out = defobj; 4181 return (0); 4182 } 4183 return (ESRCH); 4184 } 4185 4186 /* 4187 * Search the chain of DAGS cointed to by the given Needed_Entry 4188 * for a symbol of the given name. Each DAG is scanned completely 4189 * before advancing to the next one. Returns a pointer to the symbol, 4190 * or NULL if no definition was found. 4191 */ 4192 static int 4193 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4194 { 4195 const Elf_Sym *def; 4196 const Needed_Entry *n; 4197 const Obj_Entry *defobj; 4198 SymLook req1; 4199 int res; 4200 4201 def = NULL; 4202 defobj = NULL; 4203 symlook_init_from_req(&req1, req); 4204 for (n = needed; n != NULL; n = n->next) { 4205 if (n->obj == NULL || 4206 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4207 continue; 4208 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4209 def = req1.sym_out; 4210 defobj = req1.defobj_out; 4211 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4212 break; 4213 } 4214 } 4215 if (def != NULL) { 4216 req->sym_out = def; 4217 req->defobj_out = defobj; 4218 return (0); 4219 } 4220 return (ESRCH); 4221 } 4222 4223 /* 4224 * Search the symbol table of a single shared object for a symbol of 4225 * the given name and version, if requested. Returns a pointer to the 4226 * symbol, or NULL if no definition was found. If the object is 4227 * filter, return filtered symbol from filtee. 4228 * 4229 * The symbol's hash value is passed in for efficiency reasons; that 4230 * eliminates many recomputations of the hash value. 4231 */ 4232 int 4233 symlook_obj(SymLook *req, const Obj_Entry *obj) 4234 { 4235 DoneList donelist; 4236 SymLook req1; 4237 int flags, res, mres; 4238 4239 /* 4240 * If there is at least one valid hash at this point, we prefer to 4241 * use the faster GNU version if available. 4242 */ 4243 if (obj->valid_hash_gnu) 4244 mres = symlook_obj1_gnu(req, obj); 4245 else if (obj->valid_hash_sysv) 4246 mres = symlook_obj1_sysv(req, obj); 4247 else 4248 return (EINVAL); 4249 4250 if (mres == 0) { 4251 if (obj->needed_filtees != NULL) { 4252 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4253 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4254 donelist_init(&donelist); 4255 symlook_init_from_req(&req1, req); 4256 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4257 if (res == 0) { 4258 req->sym_out = req1.sym_out; 4259 req->defobj_out = req1.defobj_out; 4260 } 4261 return (res); 4262 } 4263 if (obj->needed_aux_filtees != NULL) { 4264 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4265 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4266 donelist_init(&donelist); 4267 symlook_init_from_req(&req1, req); 4268 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4269 if (res == 0) { 4270 req->sym_out = req1.sym_out; 4271 req->defobj_out = req1.defobj_out; 4272 return (res); 4273 } 4274 } 4275 } 4276 return (mres); 4277 } 4278 4279 /* Symbol match routine common to both hash functions */ 4280 static bool 4281 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4282 const unsigned long symnum) 4283 { 4284 Elf_Versym verndx; 4285 const Elf_Sym *symp; 4286 const char *strp; 4287 4288 symp = obj->symtab + symnum; 4289 strp = obj->strtab + symp->st_name; 4290 4291 switch (ELF_ST_TYPE(symp->st_info)) { 4292 case STT_FUNC: 4293 case STT_NOTYPE: 4294 case STT_OBJECT: 4295 case STT_COMMON: 4296 case STT_GNU_IFUNC: 4297 if (symp->st_value == 0) 4298 return (false); 4299 /* fallthrough */ 4300 case STT_TLS: 4301 if (symp->st_shndx != SHN_UNDEF) 4302 break; 4303 #ifndef __mips__ 4304 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4305 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4306 break; 4307 /* fallthrough */ 4308 #endif 4309 default: 4310 return (false); 4311 } 4312 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4313 return (false); 4314 4315 if (req->ventry == NULL) { 4316 if (obj->versyms != NULL) { 4317 verndx = VER_NDX(obj->versyms[symnum]); 4318 if (verndx > obj->vernum) { 4319 _rtld_error( 4320 "%s: symbol %s references wrong version %d", 4321 obj->path, obj->strtab + symnum, verndx); 4322 return (false); 4323 } 4324 /* 4325 * If we are not called from dlsym (i.e. this 4326 * is a normal relocation from unversioned 4327 * binary), accept the symbol immediately if 4328 * it happens to have first version after this 4329 * shared object became versioned. Otherwise, 4330 * if symbol is versioned and not hidden, 4331 * remember it. If it is the only symbol with 4332 * this name exported by the shared object, it 4333 * will be returned as a match by the calling 4334 * function. If symbol is global (verndx < 2) 4335 * accept it unconditionally. 4336 */ 4337 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4338 verndx == VER_NDX_GIVEN) { 4339 result->sym_out = symp; 4340 return (true); 4341 } 4342 else if (verndx >= VER_NDX_GIVEN) { 4343 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4344 == 0) { 4345 if (result->vsymp == NULL) 4346 result->vsymp = symp; 4347 result->vcount++; 4348 } 4349 return (false); 4350 } 4351 } 4352 result->sym_out = symp; 4353 return (true); 4354 } 4355 if (obj->versyms == NULL) { 4356 if (object_match_name(obj, req->ventry->name)) { 4357 _rtld_error("%s: object %s should provide version %s " 4358 "for symbol %s", obj_rtld.path, obj->path, 4359 req->ventry->name, obj->strtab + symnum); 4360 return (false); 4361 } 4362 } else { 4363 verndx = VER_NDX(obj->versyms[symnum]); 4364 if (verndx > obj->vernum) { 4365 _rtld_error("%s: symbol %s references wrong version %d", 4366 obj->path, obj->strtab + symnum, verndx); 4367 return (false); 4368 } 4369 if (obj->vertab[verndx].hash != req->ventry->hash || 4370 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4371 /* 4372 * Version does not match. Look if this is a 4373 * global symbol and if it is not hidden. If 4374 * global symbol (verndx < 2) is available, 4375 * use it. Do not return symbol if we are 4376 * called by dlvsym, because dlvsym looks for 4377 * a specific version and default one is not 4378 * what dlvsym wants. 4379 */ 4380 if ((req->flags & SYMLOOK_DLSYM) || 4381 (verndx >= VER_NDX_GIVEN) || 4382 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4383 return (false); 4384 } 4385 } 4386 result->sym_out = symp; 4387 return (true); 4388 } 4389 4390 /* 4391 * Search for symbol using SysV hash function. 4392 * obj->buckets is known not to be NULL at this point; the test for this was 4393 * performed with the obj->valid_hash_sysv assignment. 4394 */ 4395 static int 4396 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4397 { 4398 unsigned long symnum; 4399 Sym_Match_Result matchres; 4400 4401 matchres.sym_out = NULL; 4402 matchres.vsymp = NULL; 4403 matchres.vcount = 0; 4404 4405 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4406 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4407 if (symnum >= obj->nchains) 4408 return (ESRCH); /* Bad object */ 4409 4410 if (matched_symbol(req, obj, &matchres, symnum)) { 4411 req->sym_out = matchres.sym_out; 4412 req->defobj_out = obj; 4413 return (0); 4414 } 4415 } 4416 if (matchres.vcount == 1) { 4417 req->sym_out = matchres.vsymp; 4418 req->defobj_out = obj; 4419 return (0); 4420 } 4421 return (ESRCH); 4422 } 4423 4424 /* Search for symbol using GNU hash function */ 4425 static int 4426 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4427 { 4428 Elf_Addr bloom_word; 4429 const Elf32_Word *hashval; 4430 Elf32_Word bucket; 4431 Sym_Match_Result matchres; 4432 unsigned int h1, h2; 4433 unsigned long symnum; 4434 4435 matchres.sym_out = NULL; 4436 matchres.vsymp = NULL; 4437 matchres.vcount = 0; 4438 4439 /* Pick right bitmask word from Bloom filter array */ 4440 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4441 obj->maskwords_bm_gnu]; 4442 4443 /* Calculate modulus word size of gnu hash and its derivative */ 4444 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4445 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4446 4447 /* Filter out the "definitely not in set" queries */ 4448 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4449 return (ESRCH); 4450 4451 /* Locate hash chain and corresponding value element*/ 4452 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4453 if (bucket == 0) 4454 return (ESRCH); 4455 hashval = &obj->chain_zero_gnu[bucket]; 4456 do { 4457 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4458 symnum = hashval - obj->chain_zero_gnu; 4459 if (matched_symbol(req, obj, &matchres, symnum)) { 4460 req->sym_out = matchres.sym_out; 4461 req->defobj_out = obj; 4462 return (0); 4463 } 4464 } 4465 } while ((*hashval++ & 1) == 0); 4466 if (matchres.vcount == 1) { 4467 req->sym_out = matchres.vsymp; 4468 req->defobj_out = obj; 4469 return (0); 4470 } 4471 return (ESRCH); 4472 } 4473 4474 static void 4475 trace_loaded_objects(Obj_Entry *obj) 4476 { 4477 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4478 int c; 4479 4480 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4481 main_local = ""; 4482 4483 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4484 fmt1 = "\t%o => %p (%x)\n"; 4485 4486 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4487 fmt2 = "\t%o (%x)\n"; 4488 4489 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4490 4491 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4492 Needed_Entry *needed; 4493 char *name, *path; 4494 bool is_lib; 4495 4496 if (obj->marker) 4497 continue; 4498 if (list_containers && obj->needed != NULL) 4499 rtld_printf("%s:\n", obj->path); 4500 for (needed = obj->needed; needed; needed = needed->next) { 4501 if (needed->obj != NULL) { 4502 if (needed->obj->traced && !list_containers) 4503 continue; 4504 needed->obj->traced = true; 4505 path = needed->obj->path; 4506 } else 4507 path = "not found"; 4508 4509 name = (char *)obj->strtab + needed->name; 4510 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4511 4512 fmt = is_lib ? fmt1 : fmt2; 4513 while ((c = *fmt++) != '\0') { 4514 switch (c) { 4515 default: 4516 rtld_putchar(c); 4517 continue; 4518 case '\\': 4519 switch (c = *fmt) { 4520 case '\0': 4521 continue; 4522 case 'n': 4523 rtld_putchar('\n'); 4524 break; 4525 case 't': 4526 rtld_putchar('\t'); 4527 break; 4528 } 4529 break; 4530 case '%': 4531 switch (c = *fmt) { 4532 case '\0': 4533 continue; 4534 case '%': 4535 default: 4536 rtld_putchar(c); 4537 break; 4538 case 'A': 4539 rtld_putstr(main_local); 4540 break; 4541 case 'a': 4542 rtld_putstr(obj_main->path); 4543 break; 4544 case 'o': 4545 rtld_putstr(name); 4546 break; 4547 #if 0 4548 case 'm': 4549 rtld_printf("%d", sodp->sod_major); 4550 break; 4551 case 'n': 4552 rtld_printf("%d", sodp->sod_minor); 4553 break; 4554 #endif 4555 case 'p': 4556 rtld_putstr(path); 4557 break; 4558 case 'x': 4559 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4560 0); 4561 break; 4562 } 4563 break; 4564 } 4565 ++fmt; 4566 } 4567 } 4568 } 4569 } 4570 4571 /* 4572 * Unload a dlopened object and its dependencies from memory and from 4573 * our data structures. It is assumed that the DAG rooted in the 4574 * object has already been unreferenced, and that the object has a 4575 * reference count of 0. 4576 */ 4577 static void 4578 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4579 { 4580 Obj_Entry marker, *obj, *next; 4581 4582 assert(root->refcount == 0); 4583 4584 /* 4585 * Pass over the DAG removing unreferenced objects from 4586 * appropriate lists. 4587 */ 4588 unlink_object(root); 4589 4590 /* Unmap all objects that are no longer referenced. */ 4591 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4592 next = TAILQ_NEXT(obj, next); 4593 if (obj->marker || obj->refcount != 0) 4594 continue; 4595 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4596 obj->mapsize, 0, obj->path); 4597 dbg("unloading \"%s\"", obj->path); 4598 /* 4599 * Unlink the object now to prevent new references from 4600 * being acquired while the bind lock is dropped in 4601 * recursive dlclose() invocations. 4602 */ 4603 TAILQ_REMOVE(&obj_list, obj, next); 4604 obj_count--; 4605 4606 if (obj->filtees_loaded) { 4607 if (next != NULL) { 4608 init_marker(&marker); 4609 TAILQ_INSERT_BEFORE(next, &marker, next); 4610 unload_filtees(obj, lockstate); 4611 next = TAILQ_NEXT(&marker, next); 4612 TAILQ_REMOVE(&obj_list, &marker, next); 4613 } else 4614 unload_filtees(obj, lockstate); 4615 } 4616 release_object(obj); 4617 } 4618 } 4619 4620 static void 4621 unlink_object(Obj_Entry *root) 4622 { 4623 Objlist_Entry *elm; 4624 4625 if (root->refcount == 0) { 4626 /* Remove the object from the RTLD_GLOBAL list. */ 4627 objlist_remove(&list_global, root); 4628 4629 /* Remove the object from all objects' DAG lists. */ 4630 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4631 objlist_remove(&elm->obj->dldags, root); 4632 if (elm->obj != root) 4633 unlink_object(elm->obj); 4634 } 4635 } 4636 } 4637 4638 static void 4639 ref_dag(Obj_Entry *root) 4640 { 4641 Objlist_Entry *elm; 4642 4643 assert(root->dag_inited); 4644 STAILQ_FOREACH(elm, &root->dagmembers, link) 4645 elm->obj->refcount++; 4646 } 4647 4648 static void 4649 unref_dag(Obj_Entry *root) 4650 { 4651 Objlist_Entry *elm; 4652 4653 assert(root->dag_inited); 4654 STAILQ_FOREACH(elm, &root->dagmembers, link) 4655 elm->obj->refcount--; 4656 } 4657 4658 /* 4659 * Common code for MD __tls_get_addr(). 4660 */ 4661 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4662 static void * 4663 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4664 { 4665 Elf_Addr *newdtv, *dtv; 4666 RtldLockState lockstate; 4667 int to_copy; 4668 4669 dtv = *dtvp; 4670 /* Check dtv generation in case new modules have arrived */ 4671 if (dtv[0] != tls_dtv_generation) { 4672 wlock_acquire(rtld_bind_lock, &lockstate); 4673 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4674 to_copy = dtv[1]; 4675 if (to_copy > tls_max_index) 4676 to_copy = tls_max_index; 4677 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4678 newdtv[0] = tls_dtv_generation; 4679 newdtv[1] = tls_max_index; 4680 free(dtv); 4681 lock_release(rtld_bind_lock, &lockstate); 4682 dtv = *dtvp = newdtv; 4683 } 4684 4685 /* Dynamically allocate module TLS if necessary */ 4686 if (dtv[index + 1] == 0) { 4687 /* Signal safe, wlock will block out signals. */ 4688 wlock_acquire(rtld_bind_lock, &lockstate); 4689 if (!dtv[index + 1]) 4690 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4691 lock_release(rtld_bind_lock, &lockstate); 4692 } 4693 return ((void *)(dtv[index + 1] + offset)); 4694 } 4695 4696 void * 4697 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4698 { 4699 Elf_Addr *dtv; 4700 4701 dtv = *dtvp; 4702 /* Check dtv generation in case new modules have arrived */ 4703 if (__predict_true(dtv[0] == tls_dtv_generation && 4704 dtv[index + 1] != 0)) 4705 return ((void *)(dtv[index + 1] + offset)); 4706 return (tls_get_addr_slow(dtvp, index, offset)); 4707 } 4708 4709 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4710 defined(__powerpc__) || defined(__riscv) 4711 4712 /* 4713 * Allocate Static TLS using the Variant I method. 4714 */ 4715 void * 4716 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4717 { 4718 Obj_Entry *obj; 4719 char *tcb; 4720 Elf_Addr **tls; 4721 Elf_Addr *dtv; 4722 Elf_Addr addr; 4723 int i; 4724 4725 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4726 return (oldtcb); 4727 4728 assert(tcbsize >= TLS_TCB_SIZE); 4729 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4730 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4731 4732 if (oldtcb != NULL) { 4733 memcpy(tls, oldtcb, tls_static_space); 4734 free(oldtcb); 4735 4736 /* Adjust the DTV. */ 4737 dtv = tls[0]; 4738 for (i = 0; i < dtv[1]; i++) { 4739 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4740 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4741 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4742 } 4743 } 4744 } else { 4745 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4746 tls[0] = dtv; 4747 dtv[0] = tls_dtv_generation; 4748 dtv[1] = tls_max_index; 4749 4750 for (obj = globallist_curr(objs); obj != NULL; 4751 obj = globallist_next(obj)) { 4752 if (obj->tlsoffset > 0) { 4753 addr = (Elf_Addr)tls + obj->tlsoffset; 4754 if (obj->tlsinitsize > 0) 4755 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4756 if (obj->tlssize > obj->tlsinitsize) 4757 memset((void*) (addr + obj->tlsinitsize), 0, 4758 obj->tlssize - obj->tlsinitsize); 4759 dtv[obj->tlsindex + 1] = addr; 4760 } 4761 } 4762 } 4763 4764 return (tcb); 4765 } 4766 4767 void 4768 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4769 { 4770 Elf_Addr *dtv; 4771 Elf_Addr tlsstart, tlsend; 4772 int dtvsize, i; 4773 4774 assert(tcbsize >= TLS_TCB_SIZE); 4775 4776 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4777 tlsend = tlsstart + tls_static_space; 4778 4779 dtv = *(Elf_Addr **)tlsstart; 4780 dtvsize = dtv[1]; 4781 for (i = 0; i < dtvsize; i++) { 4782 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4783 free((void*)dtv[i+2]); 4784 } 4785 } 4786 free(dtv); 4787 free(tcb); 4788 } 4789 4790 #endif 4791 4792 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4793 4794 /* 4795 * Allocate Static TLS using the Variant II method. 4796 */ 4797 void * 4798 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4799 { 4800 Obj_Entry *obj; 4801 size_t size, ralign; 4802 char *tls; 4803 Elf_Addr *dtv, *olddtv; 4804 Elf_Addr segbase, oldsegbase, addr; 4805 int i; 4806 4807 ralign = tcbalign; 4808 if (tls_static_max_align > ralign) 4809 ralign = tls_static_max_align; 4810 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4811 4812 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4813 tls = malloc_aligned(size, ralign); 4814 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4815 4816 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4817 ((Elf_Addr*)segbase)[0] = segbase; 4818 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4819 4820 dtv[0] = tls_dtv_generation; 4821 dtv[1] = tls_max_index; 4822 4823 if (oldtls) { 4824 /* 4825 * Copy the static TLS block over whole. 4826 */ 4827 oldsegbase = (Elf_Addr) oldtls; 4828 memcpy((void *)(segbase - tls_static_space), 4829 (const void *)(oldsegbase - tls_static_space), 4830 tls_static_space); 4831 4832 /* 4833 * If any dynamic TLS blocks have been created tls_get_addr(), 4834 * move them over. 4835 */ 4836 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4837 for (i = 0; i < olddtv[1]; i++) { 4838 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4839 dtv[i+2] = olddtv[i+2]; 4840 olddtv[i+2] = 0; 4841 } 4842 } 4843 4844 /* 4845 * We assume that this block was the one we created with 4846 * allocate_initial_tls(). 4847 */ 4848 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4849 } else { 4850 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4851 if (obj->marker || obj->tlsoffset == 0) 4852 continue; 4853 addr = segbase - obj->tlsoffset; 4854 memset((void*) (addr + obj->tlsinitsize), 4855 0, obj->tlssize - obj->tlsinitsize); 4856 if (obj->tlsinit) 4857 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4858 dtv[obj->tlsindex + 1] = addr; 4859 } 4860 } 4861 4862 return (void*) segbase; 4863 } 4864 4865 void 4866 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4867 { 4868 Elf_Addr* dtv; 4869 size_t size, ralign; 4870 int dtvsize, i; 4871 Elf_Addr tlsstart, tlsend; 4872 4873 /* 4874 * Figure out the size of the initial TLS block so that we can 4875 * find stuff which ___tls_get_addr() allocated dynamically. 4876 */ 4877 ralign = tcbalign; 4878 if (tls_static_max_align > ralign) 4879 ralign = tls_static_max_align; 4880 size = round(tls_static_space, ralign); 4881 4882 dtv = ((Elf_Addr**)tls)[1]; 4883 dtvsize = dtv[1]; 4884 tlsend = (Elf_Addr) tls; 4885 tlsstart = tlsend - size; 4886 for (i = 0; i < dtvsize; i++) { 4887 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4888 free_aligned((void *)dtv[i + 2]); 4889 } 4890 } 4891 4892 free_aligned((void *)tlsstart); 4893 free((void*) dtv); 4894 } 4895 4896 #endif 4897 4898 /* 4899 * Allocate TLS block for module with given index. 4900 */ 4901 void * 4902 allocate_module_tls(int index) 4903 { 4904 Obj_Entry* obj; 4905 char* p; 4906 4907 TAILQ_FOREACH(obj, &obj_list, next) { 4908 if (obj->marker) 4909 continue; 4910 if (obj->tlsindex == index) 4911 break; 4912 } 4913 if (!obj) { 4914 _rtld_error("Can't find module with TLS index %d", index); 4915 rtld_die(); 4916 } 4917 4918 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4919 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4920 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4921 4922 return p; 4923 } 4924 4925 bool 4926 allocate_tls_offset(Obj_Entry *obj) 4927 { 4928 size_t off; 4929 4930 if (obj->tls_done) 4931 return true; 4932 4933 if (obj->tlssize == 0) { 4934 obj->tls_done = true; 4935 return true; 4936 } 4937 4938 if (tls_last_offset == 0) 4939 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4940 else 4941 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4942 obj->tlssize, obj->tlsalign); 4943 4944 /* 4945 * If we have already fixed the size of the static TLS block, we 4946 * must stay within that size. When allocating the static TLS, we 4947 * leave a small amount of space spare to be used for dynamically 4948 * loading modules which use static TLS. 4949 */ 4950 if (tls_static_space != 0) { 4951 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4952 return false; 4953 } else if (obj->tlsalign > tls_static_max_align) { 4954 tls_static_max_align = obj->tlsalign; 4955 } 4956 4957 tls_last_offset = obj->tlsoffset = off; 4958 tls_last_size = obj->tlssize; 4959 obj->tls_done = true; 4960 4961 return true; 4962 } 4963 4964 void 4965 free_tls_offset(Obj_Entry *obj) 4966 { 4967 4968 /* 4969 * If we were the last thing to allocate out of the static TLS 4970 * block, we give our space back to the 'allocator'. This is a 4971 * simplistic workaround to allow libGL.so.1 to be loaded and 4972 * unloaded multiple times. 4973 */ 4974 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4975 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4976 tls_last_offset -= obj->tlssize; 4977 tls_last_size = 0; 4978 } 4979 } 4980 4981 void * 4982 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4983 { 4984 void *ret; 4985 RtldLockState lockstate; 4986 4987 wlock_acquire(rtld_bind_lock, &lockstate); 4988 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4989 tcbsize, tcbalign); 4990 lock_release(rtld_bind_lock, &lockstate); 4991 return (ret); 4992 } 4993 4994 void 4995 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4996 { 4997 RtldLockState lockstate; 4998 4999 wlock_acquire(rtld_bind_lock, &lockstate); 5000 free_tls(tcb, tcbsize, tcbalign); 5001 lock_release(rtld_bind_lock, &lockstate); 5002 } 5003 5004 static void 5005 object_add_name(Obj_Entry *obj, const char *name) 5006 { 5007 Name_Entry *entry; 5008 size_t len; 5009 5010 len = strlen(name); 5011 entry = malloc(sizeof(Name_Entry) + len); 5012 5013 if (entry != NULL) { 5014 strcpy(entry->name, name); 5015 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5016 } 5017 } 5018 5019 static int 5020 object_match_name(const Obj_Entry *obj, const char *name) 5021 { 5022 Name_Entry *entry; 5023 5024 STAILQ_FOREACH(entry, &obj->names, link) { 5025 if (strcmp(name, entry->name) == 0) 5026 return (1); 5027 } 5028 return (0); 5029 } 5030 5031 static Obj_Entry * 5032 locate_dependency(const Obj_Entry *obj, const char *name) 5033 { 5034 const Objlist_Entry *entry; 5035 const Needed_Entry *needed; 5036 5037 STAILQ_FOREACH(entry, &list_main, link) { 5038 if (object_match_name(entry->obj, name)) 5039 return entry->obj; 5040 } 5041 5042 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5043 if (strcmp(obj->strtab + needed->name, name) == 0 || 5044 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5045 /* 5046 * If there is DT_NEEDED for the name we are looking for, 5047 * we are all set. Note that object might not be found if 5048 * dependency was not loaded yet, so the function can 5049 * return NULL here. This is expected and handled 5050 * properly by the caller. 5051 */ 5052 return (needed->obj); 5053 } 5054 } 5055 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5056 obj->path, name); 5057 rtld_die(); 5058 } 5059 5060 static int 5061 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5062 const Elf_Vernaux *vna) 5063 { 5064 const Elf_Verdef *vd; 5065 const char *vername; 5066 5067 vername = refobj->strtab + vna->vna_name; 5068 vd = depobj->verdef; 5069 if (vd == NULL) { 5070 _rtld_error("%s: version %s required by %s not defined", 5071 depobj->path, vername, refobj->path); 5072 return (-1); 5073 } 5074 for (;;) { 5075 if (vd->vd_version != VER_DEF_CURRENT) { 5076 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5077 depobj->path, vd->vd_version); 5078 return (-1); 5079 } 5080 if (vna->vna_hash == vd->vd_hash) { 5081 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5082 ((char *)vd + vd->vd_aux); 5083 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5084 return (0); 5085 } 5086 if (vd->vd_next == 0) 5087 break; 5088 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5089 } 5090 if (vna->vna_flags & VER_FLG_WEAK) 5091 return (0); 5092 _rtld_error("%s: version %s required by %s not found", 5093 depobj->path, vername, refobj->path); 5094 return (-1); 5095 } 5096 5097 static int 5098 rtld_verify_object_versions(Obj_Entry *obj) 5099 { 5100 const Elf_Verneed *vn; 5101 const Elf_Verdef *vd; 5102 const Elf_Verdaux *vda; 5103 const Elf_Vernaux *vna; 5104 const Obj_Entry *depobj; 5105 int maxvernum, vernum; 5106 5107 if (obj->ver_checked) 5108 return (0); 5109 obj->ver_checked = true; 5110 5111 maxvernum = 0; 5112 /* 5113 * Walk over defined and required version records and figure out 5114 * max index used by any of them. Do very basic sanity checking 5115 * while there. 5116 */ 5117 vn = obj->verneed; 5118 while (vn != NULL) { 5119 if (vn->vn_version != VER_NEED_CURRENT) { 5120 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5121 obj->path, vn->vn_version); 5122 return (-1); 5123 } 5124 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5125 for (;;) { 5126 vernum = VER_NEED_IDX(vna->vna_other); 5127 if (vernum > maxvernum) 5128 maxvernum = vernum; 5129 if (vna->vna_next == 0) 5130 break; 5131 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5132 } 5133 if (vn->vn_next == 0) 5134 break; 5135 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5136 } 5137 5138 vd = obj->verdef; 5139 while (vd != NULL) { 5140 if (vd->vd_version != VER_DEF_CURRENT) { 5141 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5142 obj->path, vd->vd_version); 5143 return (-1); 5144 } 5145 vernum = VER_DEF_IDX(vd->vd_ndx); 5146 if (vernum > maxvernum) 5147 maxvernum = vernum; 5148 if (vd->vd_next == 0) 5149 break; 5150 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5151 } 5152 5153 if (maxvernum == 0) 5154 return (0); 5155 5156 /* 5157 * Store version information in array indexable by version index. 5158 * Verify that object version requirements are satisfied along the 5159 * way. 5160 */ 5161 obj->vernum = maxvernum + 1; 5162 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5163 5164 vd = obj->verdef; 5165 while (vd != NULL) { 5166 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5167 vernum = VER_DEF_IDX(vd->vd_ndx); 5168 assert(vernum <= maxvernum); 5169 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5170 obj->vertab[vernum].hash = vd->vd_hash; 5171 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5172 obj->vertab[vernum].file = NULL; 5173 obj->vertab[vernum].flags = 0; 5174 } 5175 if (vd->vd_next == 0) 5176 break; 5177 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5178 } 5179 5180 vn = obj->verneed; 5181 while (vn != NULL) { 5182 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5183 if (depobj == NULL) 5184 return (-1); 5185 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5186 for (;;) { 5187 if (check_object_provided_version(obj, depobj, vna)) 5188 return (-1); 5189 vernum = VER_NEED_IDX(vna->vna_other); 5190 assert(vernum <= maxvernum); 5191 obj->vertab[vernum].hash = vna->vna_hash; 5192 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5193 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5194 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5195 VER_INFO_HIDDEN : 0; 5196 if (vna->vna_next == 0) 5197 break; 5198 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5199 } 5200 if (vn->vn_next == 0) 5201 break; 5202 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5203 } 5204 return 0; 5205 } 5206 5207 static int 5208 rtld_verify_versions(const Objlist *objlist) 5209 { 5210 Objlist_Entry *entry; 5211 int rc; 5212 5213 rc = 0; 5214 STAILQ_FOREACH(entry, objlist, link) { 5215 /* 5216 * Skip dummy objects or objects that have their version requirements 5217 * already checked. 5218 */ 5219 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5220 continue; 5221 if (rtld_verify_object_versions(entry->obj) == -1) { 5222 rc = -1; 5223 if (ld_tracing == NULL) 5224 break; 5225 } 5226 } 5227 if (rc == 0 || ld_tracing != NULL) 5228 rc = rtld_verify_object_versions(&obj_rtld); 5229 return rc; 5230 } 5231 5232 const Ver_Entry * 5233 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5234 { 5235 Elf_Versym vernum; 5236 5237 if (obj->vertab) { 5238 vernum = VER_NDX(obj->versyms[symnum]); 5239 if (vernum >= obj->vernum) { 5240 _rtld_error("%s: symbol %s has wrong verneed value %d", 5241 obj->path, obj->strtab + symnum, vernum); 5242 } else if (obj->vertab[vernum].hash != 0) { 5243 return &obj->vertab[vernum]; 5244 } 5245 } 5246 return NULL; 5247 } 5248 5249 int 5250 _rtld_get_stack_prot(void) 5251 { 5252 5253 return (stack_prot); 5254 } 5255 5256 int 5257 _rtld_is_dlopened(void *arg) 5258 { 5259 Obj_Entry *obj; 5260 RtldLockState lockstate; 5261 int res; 5262 5263 rlock_acquire(rtld_bind_lock, &lockstate); 5264 obj = dlcheck(arg); 5265 if (obj == NULL) 5266 obj = obj_from_addr(arg); 5267 if (obj == NULL) { 5268 _rtld_error("No shared object contains address"); 5269 lock_release(rtld_bind_lock, &lockstate); 5270 return (-1); 5271 } 5272 res = obj->dlopened ? 1 : 0; 5273 lock_release(rtld_bind_lock, &lockstate); 5274 return (res); 5275 } 5276 5277 int 5278 obj_enforce_relro(Obj_Entry *obj) 5279 { 5280 5281 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5282 PROT_READ) == -1) { 5283 _rtld_error("%s: Cannot enforce relro protection: %s", 5284 obj->path, rtld_strerror(errno)); 5285 return (-1); 5286 } 5287 return (0); 5288 } 5289 5290 static void 5291 map_stacks_exec(RtldLockState *lockstate) 5292 { 5293 void (*thr_map_stacks_exec)(void); 5294 5295 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5296 return; 5297 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5298 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5299 if (thr_map_stacks_exec != NULL) { 5300 stack_prot |= PROT_EXEC; 5301 thr_map_stacks_exec(); 5302 } 5303 } 5304 5305 void 5306 symlook_init(SymLook *dst, const char *name) 5307 { 5308 5309 bzero(dst, sizeof(*dst)); 5310 dst->name = name; 5311 dst->hash = elf_hash(name); 5312 dst->hash_gnu = gnu_hash(name); 5313 } 5314 5315 static void 5316 symlook_init_from_req(SymLook *dst, const SymLook *src) 5317 { 5318 5319 dst->name = src->name; 5320 dst->hash = src->hash; 5321 dst->hash_gnu = src->hash_gnu; 5322 dst->ventry = src->ventry; 5323 dst->flags = src->flags; 5324 dst->defobj_out = NULL; 5325 dst->sym_out = NULL; 5326 dst->lockstate = src->lockstate; 5327 } 5328 5329 static int 5330 open_binary_fd(const char *argv0, bool search_in_path) 5331 { 5332 char *pathenv, *pe, binpath[PATH_MAX]; 5333 int fd; 5334 5335 if (search_in_path && strchr(argv0, '/') == NULL) { 5336 pathenv = getenv("PATH"); 5337 if (pathenv == NULL) { 5338 rtld_printf("-p and no PATH environment variable\n"); 5339 rtld_die(); 5340 } 5341 pathenv = strdup(pathenv); 5342 if (pathenv == NULL) { 5343 rtld_printf("Cannot allocate memory\n"); 5344 rtld_die(); 5345 } 5346 fd = -1; 5347 errno = ENOENT; 5348 while ((pe = strsep(&pathenv, ":")) != NULL) { 5349 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5350 sizeof(binpath)) 5351 continue; 5352 if (binpath[0] != '\0' && 5353 strlcat(binpath, "/", sizeof(binpath)) >= 5354 sizeof(binpath)) 5355 continue; 5356 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5357 sizeof(binpath)) 5358 continue; 5359 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5360 if (fd != -1 || errno != ENOENT) 5361 break; 5362 } 5363 free(pathenv); 5364 } else { 5365 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5366 } 5367 5368 if (fd == -1) { 5369 rtld_printf("Opening %s: %s\n", argv0, 5370 rtld_strerror(errno)); 5371 rtld_die(); 5372 } 5373 return (fd); 5374 } 5375 5376 /* 5377 * Parse a set of command-line arguments. 5378 */ 5379 static int 5380 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5381 { 5382 const char *arg; 5383 int fd, i, j, arglen; 5384 char opt; 5385 5386 dbg("Parsing command-line arguments"); 5387 *use_pathp = false; 5388 *fdp = -1; 5389 5390 for (i = 1; i < argc; i++ ) { 5391 arg = argv[i]; 5392 dbg("argv[%d]: '%s'", i, arg); 5393 5394 /* 5395 * rtld arguments end with an explicit "--" or with the first 5396 * non-prefixed argument. 5397 */ 5398 if (strcmp(arg, "--") == 0) { 5399 i++; 5400 break; 5401 } 5402 if (arg[0] != '-') 5403 break; 5404 5405 /* 5406 * All other arguments are single-character options that can 5407 * be combined, so we need to search through `arg` for them. 5408 */ 5409 arglen = strlen(arg); 5410 for (j = 1; j < arglen; j++) { 5411 opt = arg[j]; 5412 if (opt == 'h') { 5413 print_usage(argv[0]); 5414 rtld_die(); 5415 } else if (opt == 'f') { 5416 /* 5417 * -f XX can be used to specify a descriptor for the 5418 * binary named at the command line (i.e., the later 5419 * argument will specify the process name but the 5420 * descriptor is what will actually be executed) 5421 */ 5422 if (j != arglen - 1) { 5423 /* -f must be the last option in, e.g., -abcf */ 5424 _rtld_error("invalid options: %s", arg); 5425 rtld_die(); 5426 } 5427 i++; 5428 fd = parse_integer(argv[i]); 5429 if (fd == -1) { 5430 _rtld_error("invalid file descriptor: '%s'", 5431 argv[i]); 5432 rtld_die(); 5433 } 5434 *fdp = fd; 5435 break; 5436 } else if (opt == 'p') { 5437 *use_pathp = true; 5438 } else { 5439 rtld_printf("invalid argument: '%s'\n", arg); 5440 print_usage(argv[0]); 5441 rtld_die(); 5442 } 5443 } 5444 } 5445 5446 return (i); 5447 } 5448 5449 /* 5450 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5451 */ 5452 static int 5453 parse_integer(const char *str) 5454 { 5455 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5456 const char *orig; 5457 int n; 5458 char c; 5459 5460 orig = str; 5461 n = 0; 5462 for (c = *str; c != '\0'; c = *++str) { 5463 if (c < '0' || c > '9') 5464 return (-1); 5465 5466 n *= RADIX; 5467 n += c - '0'; 5468 } 5469 5470 /* Make sure we actually parsed something. */ 5471 if (str == orig) 5472 return (-1); 5473 return (n); 5474 } 5475 5476 static void 5477 print_usage(const char *argv0) 5478 { 5479 5480 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5481 "\n" 5482 "Options:\n" 5483 " -h Display this help message\n" 5484 " -p Search in PATH for named binary\n" 5485 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5486 " -- End of RTLD options\n" 5487 " <binary> Name of process to execute\n" 5488 " <args> Arguments to the executed process\n", argv0); 5489 } 5490 5491 /* 5492 * Overrides for libc_pic-provided functions. 5493 */ 5494 5495 int 5496 __getosreldate(void) 5497 { 5498 size_t len; 5499 int oid[2]; 5500 int error, osrel; 5501 5502 if (osreldate != 0) 5503 return (osreldate); 5504 5505 oid[0] = CTL_KERN; 5506 oid[1] = KERN_OSRELDATE; 5507 osrel = 0; 5508 len = sizeof(osrel); 5509 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5510 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5511 osreldate = osrel; 5512 return (osreldate); 5513 } 5514 5515 void 5516 exit(int status) 5517 { 5518 5519 _exit(status); 5520 } 5521 5522 void (*__cleanup)(void); 5523 int __isthreaded = 0; 5524 int _thread_autoinit_dummy_decl = 1; 5525 5526 /* 5527 * No unresolved symbols for rtld. 5528 */ 5529 void 5530 __pthread_cxa_finalize(struct dl_phdr_info *a) 5531 { 5532 } 5533 5534 void 5535 __stack_chk_fail(void) 5536 { 5537 5538 _rtld_error("stack overflow detected; terminated"); 5539 rtld_die(); 5540 } 5541 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5542 5543 void 5544 __chk_fail(void) 5545 { 5546 5547 _rtld_error("buffer overflow detected; terminated"); 5548 rtld_die(); 5549 } 5550 5551 const char * 5552 rtld_strerror(int errnum) 5553 { 5554 5555 if (errnum < 0 || errnum >= sys_nerr) 5556 return ("Unknown error"); 5557 return (sys_errlist[errnum]); 5558 } 5559