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 /* 759 * Execute MD initializers required before we call the objects' 760 * init functions. 761 */ 762 pre_init(); 763 764 wlock_acquire(rtld_bind_lock, &lockstate); 765 if (obj_main->crt_no_init) 766 preinit_main(); 767 objlist_call_init(&initlist, &lockstate); 768 _r_debug_postinit(&obj_main->linkmap); 769 objlist_clear(&initlist); 770 dbg("loading filtees"); 771 TAILQ_FOREACH(obj, &obj_list, next) { 772 if (obj->marker) 773 continue; 774 if (ld_loadfltr || obj->z_loadfltr) 775 load_filtees(obj, 0, &lockstate); 776 } 777 lock_release(rtld_bind_lock, &lockstate); 778 779 dbg("transferring control to program entry point = %p", obj_main->entry); 780 781 /* Return the exit procedure and the program entry point. */ 782 *exit_proc = rtld_exit; 783 *objp = obj_main; 784 return (func_ptr_type) obj_main->entry; 785 } 786 787 void * 788 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 789 { 790 void *ptr; 791 Elf_Addr target; 792 793 ptr = (void *)make_function_pointer(def, obj); 794 target = call_ifunc_resolver(ptr); 795 return ((void *)target); 796 } 797 798 /* 799 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 800 * Changes to this function should be applied there as well. 801 */ 802 Elf_Addr 803 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 804 { 805 const Elf_Rel *rel; 806 const Elf_Sym *def; 807 const Obj_Entry *defobj; 808 Elf_Addr *where; 809 Elf_Addr target; 810 RtldLockState lockstate; 811 812 rlock_acquire(rtld_bind_lock, &lockstate); 813 if (sigsetjmp(lockstate.env, 0) != 0) 814 lock_upgrade(rtld_bind_lock, &lockstate); 815 if (obj->pltrel) 816 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 817 else 818 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 819 820 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 821 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 822 NULL, &lockstate); 823 if (def == NULL) 824 rtld_die(); 825 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 826 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 827 else 828 target = (Elf_Addr)(defobj->relocbase + def->st_value); 829 830 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 831 defobj->strtab + def->st_name, basename(obj->path), 832 (void *)target, basename(defobj->path)); 833 834 /* 835 * Write the new contents for the jmpslot. Note that depending on 836 * architecture, the value which we need to return back to the 837 * lazy binding trampoline may or may not be the target 838 * address. The value returned from reloc_jmpslot() is the value 839 * that the trampoline needs. 840 */ 841 target = reloc_jmpslot(where, target, defobj, obj, rel); 842 lock_release(rtld_bind_lock, &lockstate); 843 return target; 844 } 845 846 /* 847 * Error reporting function. Use it like printf. If formats the message 848 * into a buffer, and sets things up so that the next call to dlerror() 849 * will return the message. 850 */ 851 void 852 _rtld_error(const char *fmt, ...) 853 { 854 static char buf[512]; 855 va_list ap; 856 857 va_start(ap, fmt); 858 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 859 error_message = buf; 860 va_end(ap); 861 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 862 } 863 864 /* 865 * Return a dynamically-allocated copy of the current error message, if any. 866 */ 867 static char * 868 errmsg_save(void) 869 { 870 return error_message == NULL ? NULL : xstrdup(error_message); 871 } 872 873 /* 874 * Restore the current error message from a copy which was previously saved 875 * by errmsg_save(). The copy is freed. 876 */ 877 static void 878 errmsg_restore(char *saved_msg) 879 { 880 if (saved_msg == NULL) 881 error_message = NULL; 882 else { 883 _rtld_error("%s", saved_msg); 884 free(saved_msg); 885 } 886 } 887 888 static const char * 889 basename(const char *name) 890 { 891 const char *p = strrchr(name, '/'); 892 return p != NULL ? p + 1 : name; 893 } 894 895 static struct utsname uts; 896 897 static char * 898 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 899 const char *subst, bool may_free) 900 { 901 char *p, *p1, *res, *resp; 902 int subst_len, kw_len, subst_count, old_len, new_len; 903 904 kw_len = strlen(kw); 905 906 /* 907 * First, count the number of the keyword occurrences, to 908 * preallocate the final string. 909 */ 910 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 911 p1 = strstr(p, kw); 912 if (p1 == NULL) 913 break; 914 } 915 916 /* 917 * If the keyword is not found, just return. 918 * 919 * Return non-substituted string if resolution failed. We 920 * cannot do anything more reasonable, the failure mode of the 921 * caller is unresolved library anyway. 922 */ 923 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 924 return (may_free ? real : xstrdup(real)); 925 if (obj != NULL) 926 subst = obj->origin_path; 927 928 /* 929 * There is indeed something to substitute. Calculate the 930 * length of the resulting string, and allocate it. 931 */ 932 subst_len = strlen(subst); 933 old_len = strlen(real); 934 new_len = old_len + (subst_len - kw_len) * subst_count; 935 res = xmalloc(new_len + 1); 936 937 /* 938 * Now, execute the substitution loop. 939 */ 940 for (p = real, resp = res, *resp = '\0';;) { 941 p1 = strstr(p, kw); 942 if (p1 != NULL) { 943 /* Copy the prefix before keyword. */ 944 memcpy(resp, p, p1 - p); 945 resp += p1 - p; 946 /* Keyword replacement. */ 947 memcpy(resp, subst, subst_len); 948 resp += subst_len; 949 *resp = '\0'; 950 p = p1 + kw_len; 951 } else 952 break; 953 } 954 955 /* Copy to the end of string and finish. */ 956 strcat(resp, p); 957 if (may_free) 958 free(real); 959 return (res); 960 } 961 962 static char * 963 origin_subst(Obj_Entry *obj, char *real) 964 { 965 char *res1, *res2, *res3, *res4; 966 967 if (obj == NULL || !trust) 968 return (xstrdup(real)); 969 if (uts.sysname[0] == '\0') { 970 if (uname(&uts) != 0) { 971 _rtld_error("utsname failed: %d", errno); 972 return (NULL); 973 } 974 } 975 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 976 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 977 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 978 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 979 return (res4); 980 } 981 982 void 983 rtld_die(void) 984 { 985 const char *msg = dlerror(); 986 987 if (msg == NULL) 988 msg = "Fatal error"; 989 rtld_fdputstr(STDERR_FILENO, msg); 990 rtld_fdputchar(STDERR_FILENO, '\n'); 991 _exit(1); 992 } 993 994 /* 995 * Process a shared object's DYNAMIC section, and save the important 996 * information in its Obj_Entry structure. 997 */ 998 static void 999 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1000 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1001 { 1002 const Elf_Dyn *dynp; 1003 Needed_Entry **needed_tail = &obj->needed; 1004 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1005 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1006 const Elf_Hashelt *hashtab; 1007 const Elf32_Word *hashval; 1008 Elf32_Word bkt, nmaskwords; 1009 int bloom_size32; 1010 int plttype = DT_REL; 1011 1012 *dyn_rpath = NULL; 1013 *dyn_soname = NULL; 1014 *dyn_runpath = NULL; 1015 1016 obj->bind_now = false; 1017 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1018 switch (dynp->d_tag) { 1019 1020 case DT_REL: 1021 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1022 break; 1023 1024 case DT_RELSZ: 1025 obj->relsize = dynp->d_un.d_val; 1026 break; 1027 1028 case DT_RELENT: 1029 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1030 break; 1031 1032 case DT_JMPREL: 1033 obj->pltrel = (const Elf_Rel *) 1034 (obj->relocbase + dynp->d_un.d_ptr); 1035 break; 1036 1037 case DT_PLTRELSZ: 1038 obj->pltrelsize = dynp->d_un.d_val; 1039 break; 1040 1041 case DT_RELA: 1042 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1043 break; 1044 1045 case DT_RELASZ: 1046 obj->relasize = dynp->d_un.d_val; 1047 break; 1048 1049 case DT_RELAENT: 1050 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1051 break; 1052 1053 case DT_PLTREL: 1054 plttype = dynp->d_un.d_val; 1055 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1056 break; 1057 1058 case DT_SYMTAB: 1059 obj->symtab = (const Elf_Sym *) 1060 (obj->relocbase + dynp->d_un.d_ptr); 1061 break; 1062 1063 case DT_SYMENT: 1064 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1065 break; 1066 1067 case DT_STRTAB: 1068 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1069 break; 1070 1071 case DT_STRSZ: 1072 obj->strsize = dynp->d_un.d_val; 1073 break; 1074 1075 case DT_VERNEED: 1076 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1077 dynp->d_un.d_val); 1078 break; 1079 1080 case DT_VERNEEDNUM: 1081 obj->verneednum = dynp->d_un.d_val; 1082 break; 1083 1084 case DT_VERDEF: 1085 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1086 dynp->d_un.d_val); 1087 break; 1088 1089 case DT_VERDEFNUM: 1090 obj->verdefnum = dynp->d_un.d_val; 1091 break; 1092 1093 case DT_VERSYM: 1094 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1095 dynp->d_un.d_val); 1096 break; 1097 1098 case DT_HASH: 1099 { 1100 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1101 dynp->d_un.d_ptr); 1102 obj->nbuckets = hashtab[0]; 1103 obj->nchains = hashtab[1]; 1104 obj->buckets = hashtab + 2; 1105 obj->chains = obj->buckets + obj->nbuckets; 1106 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1107 obj->buckets != NULL; 1108 } 1109 break; 1110 1111 case DT_GNU_HASH: 1112 { 1113 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1114 dynp->d_un.d_ptr); 1115 obj->nbuckets_gnu = hashtab[0]; 1116 obj->symndx_gnu = hashtab[1]; 1117 nmaskwords = hashtab[2]; 1118 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1119 obj->maskwords_bm_gnu = nmaskwords - 1; 1120 obj->shift2_gnu = hashtab[3]; 1121 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1122 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1123 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1124 obj->symndx_gnu; 1125 /* Number of bitmask words is required to be power of 2 */ 1126 obj->valid_hash_gnu = powerof2(nmaskwords) && 1127 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1128 } 1129 break; 1130 1131 case DT_NEEDED: 1132 if (!obj->rtld) { 1133 Needed_Entry *nep = NEW(Needed_Entry); 1134 nep->name = dynp->d_un.d_val; 1135 nep->obj = NULL; 1136 nep->next = NULL; 1137 1138 *needed_tail = nep; 1139 needed_tail = &nep->next; 1140 } 1141 break; 1142 1143 case DT_FILTER: 1144 if (!obj->rtld) { 1145 Needed_Entry *nep = NEW(Needed_Entry); 1146 nep->name = dynp->d_un.d_val; 1147 nep->obj = NULL; 1148 nep->next = NULL; 1149 1150 *needed_filtees_tail = nep; 1151 needed_filtees_tail = &nep->next; 1152 } 1153 break; 1154 1155 case DT_AUXILIARY: 1156 if (!obj->rtld) { 1157 Needed_Entry *nep = NEW(Needed_Entry); 1158 nep->name = dynp->d_un.d_val; 1159 nep->obj = NULL; 1160 nep->next = NULL; 1161 1162 *needed_aux_filtees_tail = nep; 1163 needed_aux_filtees_tail = &nep->next; 1164 } 1165 break; 1166 1167 case DT_PLTGOT: 1168 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1169 break; 1170 1171 case DT_TEXTREL: 1172 obj->textrel = true; 1173 break; 1174 1175 case DT_SYMBOLIC: 1176 obj->symbolic = true; 1177 break; 1178 1179 case DT_RPATH: 1180 /* 1181 * We have to wait until later to process this, because we 1182 * might not have gotten the address of the string table yet. 1183 */ 1184 *dyn_rpath = dynp; 1185 break; 1186 1187 case DT_SONAME: 1188 *dyn_soname = dynp; 1189 break; 1190 1191 case DT_RUNPATH: 1192 *dyn_runpath = dynp; 1193 break; 1194 1195 case DT_INIT: 1196 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1197 break; 1198 1199 case DT_PREINIT_ARRAY: 1200 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1201 break; 1202 1203 case DT_PREINIT_ARRAYSZ: 1204 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1205 break; 1206 1207 case DT_INIT_ARRAY: 1208 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1209 break; 1210 1211 case DT_INIT_ARRAYSZ: 1212 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1213 break; 1214 1215 case DT_FINI: 1216 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1217 break; 1218 1219 case DT_FINI_ARRAY: 1220 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1221 break; 1222 1223 case DT_FINI_ARRAYSZ: 1224 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1225 break; 1226 1227 /* 1228 * Don't process DT_DEBUG on MIPS as the dynamic section 1229 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1230 */ 1231 1232 #ifndef __mips__ 1233 case DT_DEBUG: 1234 if (!early) 1235 dbg("Filling in DT_DEBUG entry"); 1236 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1237 break; 1238 #endif 1239 1240 case DT_FLAGS: 1241 if (dynp->d_un.d_val & DF_ORIGIN) 1242 obj->z_origin = true; 1243 if (dynp->d_un.d_val & DF_SYMBOLIC) 1244 obj->symbolic = true; 1245 if (dynp->d_un.d_val & DF_TEXTREL) 1246 obj->textrel = true; 1247 if (dynp->d_un.d_val & DF_BIND_NOW) 1248 obj->bind_now = true; 1249 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1250 ;*/ 1251 break; 1252 #ifdef __mips__ 1253 case DT_MIPS_LOCAL_GOTNO: 1254 obj->local_gotno = dynp->d_un.d_val; 1255 break; 1256 1257 case DT_MIPS_SYMTABNO: 1258 obj->symtabno = dynp->d_un.d_val; 1259 break; 1260 1261 case DT_MIPS_GOTSYM: 1262 obj->gotsym = dynp->d_un.d_val; 1263 break; 1264 1265 case DT_MIPS_RLD_MAP: 1266 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1267 break; 1268 1269 case DT_MIPS_PLTGOT: 1270 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1271 dynp->d_un.d_ptr); 1272 break; 1273 1274 #endif 1275 1276 #ifdef __powerpc64__ 1277 case DT_PPC64_GLINK: 1278 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1279 break; 1280 #endif 1281 1282 case DT_FLAGS_1: 1283 if (dynp->d_un.d_val & DF_1_NOOPEN) 1284 obj->z_noopen = true; 1285 if (dynp->d_un.d_val & DF_1_ORIGIN) 1286 obj->z_origin = true; 1287 if (dynp->d_un.d_val & DF_1_GLOBAL) 1288 obj->z_global = true; 1289 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1290 obj->bind_now = true; 1291 if (dynp->d_un.d_val & DF_1_NODELETE) 1292 obj->z_nodelete = true; 1293 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1294 obj->z_loadfltr = true; 1295 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1296 obj->z_interpose = true; 1297 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1298 obj->z_nodeflib = true; 1299 break; 1300 1301 default: 1302 if (!early) { 1303 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1304 (long)dynp->d_tag); 1305 } 1306 break; 1307 } 1308 } 1309 1310 obj->traced = false; 1311 1312 if (plttype == DT_RELA) { 1313 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1314 obj->pltrel = NULL; 1315 obj->pltrelasize = obj->pltrelsize; 1316 obj->pltrelsize = 0; 1317 } 1318 1319 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1320 if (obj->valid_hash_sysv) 1321 obj->dynsymcount = obj->nchains; 1322 else if (obj->valid_hash_gnu) { 1323 obj->dynsymcount = 0; 1324 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1325 if (obj->buckets_gnu[bkt] == 0) 1326 continue; 1327 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1328 do 1329 obj->dynsymcount++; 1330 while ((*hashval++ & 1u) == 0); 1331 } 1332 obj->dynsymcount += obj->symndx_gnu; 1333 } 1334 } 1335 1336 static bool 1337 obj_resolve_origin(Obj_Entry *obj) 1338 { 1339 1340 if (obj->origin_path != NULL) 1341 return (true); 1342 obj->origin_path = xmalloc(PATH_MAX); 1343 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1344 } 1345 1346 static void 1347 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1348 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1349 { 1350 1351 if (obj->z_origin && !obj_resolve_origin(obj)) 1352 rtld_die(); 1353 1354 if (dyn_runpath != NULL) { 1355 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1356 obj->runpath = origin_subst(obj, obj->runpath); 1357 } else if (dyn_rpath != NULL) { 1358 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1359 obj->rpath = origin_subst(obj, obj->rpath); 1360 } 1361 if (dyn_soname != NULL) 1362 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1363 } 1364 1365 static void 1366 digest_dynamic(Obj_Entry *obj, int early) 1367 { 1368 const Elf_Dyn *dyn_rpath; 1369 const Elf_Dyn *dyn_soname; 1370 const Elf_Dyn *dyn_runpath; 1371 1372 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1373 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1374 } 1375 1376 /* 1377 * Process a shared object's program header. This is used only for the 1378 * main program, when the kernel has already loaded the main program 1379 * into memory before calling the dynamic linker. It creates and 1380 * returns an Obj_Entry structure. 1381 */ 1382 static Obj_Entry * 1383 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1384 { 1385 Obj_Entry *obj; 1386 const Elf_Phdr *phlimit = phdr + phnum; 1387 const Elf_Phdr *ph; 1388 Elf_Addr note_start, note_end; 1389 int nsegs = 0; 1390 1391 obj = obj_new(); 1392 for (ph = phdr; ph < phlimit; ph++) { 1393 if (ph->p_type != PT_PHDR) 1394 continue; 1395 1396 obj->phdr = phdr; 1397 obj->phsize = ph->p_memsz; 1398 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1399 break; 1400 } 1401 1402 obj->stack_flags = PF_X | PF_R | PF_W; 1403 1404 for (ph = phdr; ph < phlimit; ph++) { 1405 switch (ph->p_type) { 1406 1407 case PT_INTERP: 1408 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1409 break; 1410 1411 case PT_LOAD: 1412 if (nsegs == 0) { /* First load segment */ 1413 obj->vaddrbase = trunc_page(ph->p_vaddr); 1414 obj->mapbase = obj->vaddrbase + obj->relocbase; 1415 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1416 obj->vaddrbase; 1417 } else { /* Last load segment */ 1418 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1419 obj->vaddrbase; 1420 } 1421 nsegs++; 1422 break; 1423 1424 case PT_DYNAMIC: 1425 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1426 break; 1427 1428 case PT_TLS: 1429 obj->tlsindex = 1; 1430 obj->tlssize = ph->p_memsz; 1431 obj->tlsalign = ph->p_align; 1432 obj->tlsinitsize = ph->p_filesz; 1433 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1434 break; 1435 1436 case PT_GNU_STACK: 1437 obj->stack_flags = ph->p_flags; 1438 break; 1439 1440 case PT_GNU_RELRO: 1441 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1442 obj->relro_size = round_page(ph->p_memsz); 1443 break; 1444 1445 case PT_NOTE: 1446 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1447 note_end = note_start + ph->p_filesz; 1448 digest_notes(obj, note_start, note_end); 1449 break; 1450 } 1451 } 1452 if (nsegs < 1) { 1453 _rtld_error("%s: too few PT_LOAD segments", path); 1454 return NULL; 1455 } 1456 1457 obj->entry = entry; 1458 return obj; 1459 } 1460 1461 void 1462 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1463 { 1464 const Elf_Note *note; 1465 const char *note_name; 1466 uintptr_t p; 1467 1468 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1469 note = (const Elf_Note *)((const char *)(note + 1) + 1470 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1471 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1472 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1473 note->n_descsz != sizeof(int32_t)) 1474 continue; 1475 if (note->n_type != NT_FREEBSD_ABI_TAG && 1476 note->n_type != NT_FREEBSD_NOINIT_TAG) 1477 continue; 1478 note_name = (const char *)(note + 1); 1479 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1480 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1481 continue; 1482 switch (note->n_type) { 1483 case NT_FREEBSD_ABI_TAG: 1484 /* FreeBSD osrel note */ 1485 p = (uintptr_t)(note + 1); 1486 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1487 obj->osrel = *(const int32_t *)(p); 1488 dbg("note osrel %d", obj->osrel); 1489 break; 1490 case NT_FREEBSD_NOINIT_TAG: 1491 /* FreeBSD 'crt does not call init' note */ 1492 obj->crt_no_init = true; 1493 dbg("note crt_no_init"); 1494 break; 1495 } 1496 } 1497 } 1498 1499 static Obj_Entry * 1500 dlcheck(void *handle) 1501 { 1502 Obj_Entry *obj; 1503 1504 TAILQ_FOREACH(obj, &obj_list, next) { 1505 if (obj == (Obj_Entry *) handle) 1506 break; 1507 } 1508 1509 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1510 _rtld_error("Invalid shared object handle %p", handle); 1511 return NULL; 1512 } 1513 return obj; 1514 } 1515 1516 /* 1517 * If the given object is already in the donelist, return true. Otherwise 1518 * add the object to the list and return false. 1519 */ 1520 static bool 1521 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1522 { 1523 unsigned int i; 1524 1525 for (i = 0; i < dlp->num_used; i++) 1526 if (dlp->objs[i] == obj) 1527 return true; 1528 /* 1529 * Our donelist allocation should always be sufficient. But if 1530 * our threads locking isn't working properly, more shared objects 1531 * could have been loaded since we allocated the list. That should 1532 * never happen, but we'll handle it properly just in case it does. 1533 */ 1534 if (dlp->num_used < dlp->num_alloc) 1535 dlp->objs[dlp->num_used++] = obj; 1536 return false; 1537 } 1538 1539 /* 1540 * Hash function for symbol table lookup. Don't even think about changing 1541 * this. It is specified by the System V ABI. 1542 */ 1543 unsigned long 1544 elf_hash(const char *name) 1545 { 1546 const unsigned char *p = (const unsigned char *) name; 1547 unsigned long h = 0; 1548 unsigned long g; 1549 1550 while (*p != '\0') { 1551 h = (h << 4) + *p++; 1552 if ((g = h & 0xf0000000) != 0) 1553 h ^= g >> 24; 1554 h &= ~g; 1555 } 1556 return h; 1557 } 1558 1559 /* 1560 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1561 * unsigned in case it's implemented with a wider type. 1562 */ 1563 static uint32_t 1564 gnu_hash(const char *s) 1565 { 1566 uint32_t h; 1567 unsigned char c; 1568 1569 h = 5381; 1570 for (c = *s; c != '\0'; c = *++s) 1571 h = h * 33 + c; 1572 return (h & 0xffffffff); 1573 } 1574 1575 1576 /* 1577 * Find the library with the given name, and return its full pathname. 1578 * The returned string is dynamically allocated. Generates an error 1579 * message and returns NULL if the library cannot be found. 1580 * 1581 * If the second argument is non-NULL, then it refers to an already- 1582 * loaded shared object, whose library search path will be searched. 1583 * 1584 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1585 * descriptor (which is close-on-exec) will be passed out via the third 1586 * argument. 1587 * 1588 * The search order is: 1589 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1590 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1591 * LD_LIBRARY_PATH 1592 * DT_RUNPATH in the referencing file 1593 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1594 * from list) 1595 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1596 * 1597 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1598 */ 1599 static char * 1600 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1601 { 1602 char *pathname; 1603 char *name; 1604 bool nodeflib, objgiven; 1605 1606 objgiven = refobj != NULL; 1607 1608 if (libmap_disable || !objgiven || 1609 (name = lm_find(refobj->path, xname)) == NULL) 1610 name = (char *)xname; 1611 1612 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1613 if (name[0] != '/' && !trust) { 1614 _rtld_error("Absolute pathname required " 1615 "for shared object \"%s\"", name); 1616 return (NULL); 1617 } 1618 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1619 __DECONST(char *, name))); 1620 } 1621 1622 dbg(" Searching for \"%s\"", name); 1623 1624 /* 1625 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1626 * back to pre-conforming behaviour if user requested so with 1627 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1628 * nodeflib. 1629 */ 1630 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1631 pathname = search_library_path(name, ld_library_path, fdp); 1632 if (pathname != NULL) 1633 return (pathname); 1634 if (refobj != NULL) { 1635 pathname = search_library_path(name, refobj->rpath, fdp); 1636 if (pathname != NULL) 1637 return (pathname); 1638 } 1639 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1640 if (pathname != NULL) 1641 return (pathname); 1642 pathname = search_library_path(name, gethints(false), fdp); 1643 if (pathname != NULL) 1644 return (pathname); 1645 pathname = search_library_path(name, ld_standard_library_path, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 } else { 1649 nodeflib = objgiven ? refobj->z_nodeflib : false; 1650 if (objgiven) { 1651 pathname = search_library_path(name, refobj->rpath, fdp); 1652 if (pathname != NULL) 1653 return (pathname); 1654 } 1655 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1656 pathname = search_library_path(name, obj_main->rpath, fdp); 1657 if (pathname != NULL) 1658 return (pathname); 1659 } 1660 pathname = search_library_path(name, ld_library_path, fdp); 1661 if (pathname != NULL) 1662 return (pathname); 1663 if (objgiven) { 1664 pathname = search_library_path(name, refobj->runpath, fdp); 1665 if (pathname != NULL) 1666 return (pathname); 1667 } 1668 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1669 if (pathname != NULL) 1670 return (pathname); 1671 pathname = search_library_path(name, gethints(nodeflib), fdp); 1672 if (pathname != NULL) 1673 return (pathname); 1674 if (objgiven && !nodeflib) { 1675 pathname = search_library_path(name, 1676 ld_standard_library_path, fdp); 1677 if (pathname != NULL) 1678 return (pathname); 1679 } 1680 } 1681 1682 if (objgiven && refobj->path != NULL) { 1683 _rtld_error("Shared object \"%s\" not found, " 1684 "required by \"%s\"", name, basename(refobj->path)); 1685 } else { 1686 _rtld_error("Shared object \"%s\" not found", name); 1687 } 1688 return (NULL); 1689 } 1690 1691 /* 1692 * Given a symbol number in a referencing object, find the corresponding 1693 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1694 * no definition was found. Returns a pointer to the Obj_Entry of the 1695 * defining object via the reference parameter DEFOBJ_OUT. 1696 */ 1697 const Elf_Sym * 1698 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1699 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1700 RtldLockState *lockstate) 1701 { 1702 const Elf_Sym *ref; 1703 const Elf_Sym *def; 1704 const Obj_Entry *defobj; 1705 const Ver_Entry *ve; 1706 SymLook req; 1707 const char *name; 1708 int res; 1709 1710 /* 1711 * If we have already found this symbol, get the information from 1712 * the cache. 1713 */ 1714 if (symnum >= refobj->dynsymcount) 1715 return NULL; /* Bad object */ 1716 if (cache != NULL && cache[symnum].sym != NULL) { 1717 *defobj_out = cache[symnum].obj; 1718 return cache[symnum].sym; 1719 } 1720 1721 ref = refobj->symtab + symnum; 1722 name = refobj->strtab + ref->st_name; 1723 def = NULL; 1724 defobj = NULL; 1725 ve = NULL; 1726 1727 /* 1728 * We don't have to do a full scale lookup if the symbol is local. 1729 * We know it will bind to the instance in this load module; to 1730 * which we already have a pointer (ie ref). By not doing a lookup, 1731 * we not only improve performance, but it also avoids unresolvable 1732 * symbols when local symbols are not in the hash table. This has 1733 * been seen with the ia64 toolchain. 1734 */ 1735 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1736 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1737 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1738 symnum); 1739 } 1740 symlook_init(&req, name); 1741 req.flags = flags; 1742 ve = req.ventry = fetch_ventry(refobj, symnum); 1743 req.lockstate = lockstate; 1744 res = symlook_default(&req, refobj); 1745 if (res == 0) { 1746 def = req.sym_out; 1747 defobj = req.defobj_out; 1748 } 1749 } else { 1750 def = ref; 1751 defobj = refobj; 1752 } 1753 1754 /* 1755 * If we found no definition and the reference is weak, treat the 1756 * symbol as having the value zero. 1757 */ 1758 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1759 def = &sym_zero; 1760 defobj = obj_main; 1761 } 1762 1763 if (def != NULL) { 1764 *defobj_out = defobj; 1765 /* Record the information in the cache to avoid subsequent lookups. */ 1766 if (cache != NULL) { 1767 cache[symnum].sym = def; 1768 cache[symnum].obj = defobj; 1769 } 1770 } else { 1771 if (refobj != &obj_rtld) 1772 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1773 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1774 } 1775 return def; 1776 } 1777 1778 /* 1779 * Return the search path from the ldconfig hints file, reading it if 1780 * necessary. If nostdlib is true, then the default search paths are 1781 * not added to result. 1782 * 1783 * Returns NULL if there are problems with the hints file, 1784 * or if the search path there is empty. 1785 */ 1786 static const char * 1787 gethints(bool nostdlib) 1788 { 1789 static char *hints, *filtered_path; 1790 static struct elfhints_hdr hdr; 1791 struct fill_search_info_args sargs, hargs; 1792 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1793 struct dl_serpath *SLPpath, *hintpath; 1794 char *p; 1795 struct stat hint_stat; 1796 unsigned int SLPndx, hintndx, fndx, fcount; 1797 int fd; 1798 size_t flen; 1799 uint32_t dl; 1800 bool skip; 1801 1802 /* First call, read the hints file */ 1803 if (hints == NULL) { 1804 /* Keep from trying again in case the hints file is bad. */ 1805 hints = ""; 1806 1807 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1808 return (NULL); 1809 1810 /* 1811 * Check of hdr.dirlistlen value against type limit 1812 * intends to pacify static analyzers. Further 1813 * paranoia leads to checks that dirlist is fully 1814 * contained in the file range. 1815 */ 1816 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1817 hdr.magic != ELFHINTS_MAGIC || 1818 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1819 fstat(fd, &hint_stat) == -1) { 1820 cleanup1: 1821 close(fd); 1822 hdr.dirlistlen = 0; 1823 return (NULL); 1824 } 1825 dl = hdr.strtab; 1826 if (dl + hdr.dirlist < dl) 1827 goto cleanup1; 1828 dl += hdr.dirlist; 1829 if (dl + hdr.dirlistlen < dl) 1830 goto cleanup1; 1831 dl += hdr.dirlistlen; 1832 if (dl > hint_stat.st_size) 1833 goto cleanup1; 1834 p = xmalloc(hdr.dirlistlen + 1); 1835 if (pread(fd, p, hdr.dirlistlen + 1, 1836 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1837 p[hdr.dirlistlen] != '\0') { 1838 free(p); 1839 goto cleanup1; 1840 } 1841 hints = p; 1842 close(fd); 1843 } 1844 1845 /* 1846 * If caller agreed to receive list which includes the default 1847 * paths, we are done. Otherwise, if we still did not 1848 * calculated filtered result, do it now. 1849 */ 1850 if (!nostdlib) 1851 return (hints[0] != '\0' ? hints : NULL); 1852 if (filtered_path != NULL) 1853 goto filt_ret; 1854 1855 /* 1856 * Obtain the list of all configured search paths, and the 1857 * list of the default paths. 1858 * 1859 * First estimate the size of the results. 1860 */ 1861 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1862 smeta.dls_cnt = 0; 1863 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1864 hmeta.dls_cnt = 0; 1865 1866 sargs.request = RTLD_DI_SERINFOSIZE; 1867 sargs.serinfo = &smeta; 1868 hargs.request = RTLD_DI_SERINFOSIZE; 1869 hargs.serinfo = &hmeta; 1870 1871 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1872 path_enumerate(hints, fill_search_info, &hargs); 1873 1874 SLPinfo = xmalloc(smeta.dls_size); 1875 hintinfo = xmalloc(hmeta.dls_size); 1876 1877 /* 1878 * Next fetch both sets of paths. 1879 */ 1880 sargs.request = RTLD_DI_SERINFO; 1881 sargs.serinfo = SLPinfo; 1882 sargs.serpath = &SLPinfo->dls_serpath[0]; 1883 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1884 1885 hargs.request = RTLD_DI_SERINFO; 1886 hargs.serinfo = hintinfo; 1887 hargs.serpath = &hintinfo->dls_serpath[0]; 1888 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1889 1890 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1891 path_enumerate(hints, fill_search_info, &hargs); 1892 1893 /* 1894 * Now calculate the difference between two sets, by excluding 1895 * standard paths from the full set. 1896 */ 1897 fndx = 0; 1898 fcount = 0; 1899 filtered_path = xmalloc(hdr.dirlistlen + 1); 1900 hintpath = &hintinfo->dls_serpath[0]; 1901 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1902 skip = false; 1903 SLPpath = &SLPinfo->dls_serpath[0]; 1904 /* 1905 * Check each standard path against current. 1906 */ 1907 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1908 /* matched, skip the path */ 1909 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1910 skip = true; 1911 break; 1912 } 1913 } 1914 if (skip) 1915 continue; 1916 /* 1917 * Not matched against any standard path, add the path 1918 * to result. Separate consequtive paths with ':'. 1919 */ 1920 if (fcount > 0) { 1921 filtered_path[fndx] = ':'; 1922 fndx++; 1923 } 1924 fcount++; 1925 flen = strlen(hintpath->dls_name); 1926 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1927 fndx += flen; 1928 } 1929 filtered_path[fndx] = '\0'; 1930 1931 free(SLPinfo); 1932 free(hintinfo); 1933 1934 filt_ret: 1935 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1936 } 1937 1938 static void 1939 init_dag(Obj_Entry *root) 1940 { 1941 const Needed_Entry *needed; 1942 const Objlist_Entry *elm; 1943 DoneList donelist; 1944 1945 if (root->dag_inited) 1946 return; 1947 donelist_init(&donelist); 1948 1949 /* Root object belongs to own DAG. */ 1950 objlist_push_tail(&root->dldags, root); 1951 objlist_push_tail(&root->dagmembers, root); 1952 donelist_check(&donelist, root); 1953 1954 /* 1955 * Add dependencies of root object to DAG in breadth order 1956 * by exploiting the fact that each new object get added 1957 * to the tail of the dagmembers list. 1958 */ 1959 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1960 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1961 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1962 continue; 1963 objlist_push_tail(&needed->obj->dldags, root); 1964 objlist_push_tail(&root->dagmembers, needed->obj); 1965 } 1966 } 1967 root->dag_inited = true; 1968 } 1969 1970 static void 1971 init_marker(Obj_Entry *marker) 1972 { 1973 1974 bzero(marker, sizeof(*marker)); 1975 marker->marker = true; 1976 } 1977 1978 Obj_Entry * 1979 globallist_curr(const Obj_Entry *obj) 1980 { 1981 1982 for (;;) { 1983 if (obj == NULL) 1984 return (NULL); 1985 if (!obj->marker) 1986 return (__DECONST(Obj_Entry *, obj)); 1987 obj = TAILQ_PREV(obj, obj_entry_q, next); 1988 } 1989 } 1990 1991 Obj_Entry * 1992 globallist_next(const Obj_Entry *obj) 1993 { 1994 1995 for (;;) { 1996 obj = TAILQ_NEXT(obj, next); 1997 if (obj == NULL) 1998 return (NULL); 1999 if (!obj->marker) 2000 return (__DECONST(Obj_Entry *, obj)); 2001 } 2002 } 2003 2004 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2005 static void 2006 hold_object(Obj_Entry *obj) 2007 { 2008 2009 obj->holdcount++; 2010 } 2011 2012 static void 2013 unhold_object(Obj_Entry *obj) 2014 { 2015 2016 assert(obj->holdcount > 0); 2017 if (--obj->holdcount == 0 && obj->unholdfree) 2018 release_object(obj); 2019 } 2020 2021 static void 2022 process_z(Obj_Entry *root) 2023 { 2024 const Objlist_Entry *elm; 2025 Obj_Entry *obj; 2026 2027 /* 2028 * Walk over object DAG and process every dependent object 2029 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2030 * to grow their own DAG. 2031 * 2032 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2033 * symlook_global() to work. 2034 * 2035 * For DF_1_NODELETE, the DAG should have its reference upped. 2036 */ 2037 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2038 obj = elm->obj; 2039 if (obj == NULL) 2040 continue; 2041 if (obj->z_nodelete && !obj->ref_nodel) { 2042 dbg("obj %s -z nodelete", obj->path); 2043 init_dag(obj); 2044 ref_dag(obj); 2045 obj->ref_nodel = true; 2046 } 2047 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2048 dbg("obj %s -z global", obj->path); 2049 objlist_push_tail(&list_global, obj); 2050 init_dag(obj); 2051 } 2052 } 2053 } 2054 /* 2055 * Initialize the dynamic linker. The argument is the address at which 2056 * the dynamic linker has been mapped into memory. The primary task of 2057 * this function is to relocate the dynamic linker. 2058 */ 2059 static void 2060 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2061 { 2062 Obj_Entry objtmp; /* Temporary rtld object */ 2063 const Elf_Ehdr *ehdr; 2064 const Elf_Dyn *dyn_rpath; 2065 const Elf_Dyn *dyn_soname; 2066 const Elf_Dyn *dyn_runpath; 2067 2068 #ifdef RTLD_INIT_PAGESIZES_EARLY 2069 /* The page size is required by the dynamic memory allocator. */ 2070 init_pagesizes(aux_info); 2071 #endif 2072 2073 /* 2074 * Conjure up an Obj_Entry structure for the dynamic linker. 2075 * 2076 * The "path" member can't be initialized yet because string constants 2077 * cannot yet be accessed. Below we will set it correctly. 2078 */ 2079 memset(&objtmp, 0, sizeof(objtmp)); 2080 objtmp.path = NULL; 2081 objtmp.rtld = true; 2082 objtmp.mapbase = mapbase; 2083 #ifdef PIC 2084 objtmp.relocbase = mapbase; 2085 #endif 2086 2087 objtmp.dynamic = rtld_dynamic(&objtmp); 2088 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2089 assert(objtmp.needed == NULL); 2090 #if !defined(__mips__) 2091 /* MIPS has a bogus DT_TEXTREL. */ 2092 assert(!objtmp.textrel); 2093 #endif 2094 /* 2095 * Temporarily put the dynamic linker entry into the object list, so 2096 * that symbols can be found. 2097 */ 2098 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2099 2100 ehdr = (Elf_Ehdr *)mapbase; 2101 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2102 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2103 2104 /* Initialize the object list. */ 2105 TAILQ_INIT(&obj_list); 2106 2107 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2108 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2109 2110 #ifndef RTLD_INIT_PAGESIZES_EARLY 2111 /* The page size is required by the dynamic memory allocator. */ 2112 init_pagesizes(aux_info); 2113 #endif 2114 2115 if (aux_info[AT_OSRELDATE] != NULL) 2116 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2117 2118 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2119 2120 /* Replace the path with a dynamically allocated copy. */ 2121 obj_rtld.path = xstrdup(ld_path_rtld); 2122 2123 r_debug.r_brk = r_debug_state; 2124 r_debug.r_state = RT_CONSISTENT; 2125 } 2126 2127 /* 2128 * Retrieve the array of supported page sizes. The kernel provides the page 2129 * sizes in increasing order. 2130 */ 2131 static void 2132 init_pagesizes(Elf_Auxinfo **aux_info) 2133 { 2134 static size_t psa[MAXPAGESIZES]; 2135 int mib[2]; 2136 size_t len, size; 2137 2138 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2139 NULL) { 2140 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2141 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2142 } else { 2143 len = 2; 2144 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2145 size = sizeof(psa); 2146 else { 2147 /* As a fallback, retrieve the base page size. */ 2148 size = sizeof(psa[0]); 2149 if (aux_info[AT_PAGESZ] != NULL) { 2150 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2151 goto psa_filled; 2152 } else { 2153 mib[0] = CTL_HW; 2154 mib[1] = HW_PAGESIZE; 2155 len = 2; 2156 } 2157 } 2158 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2159 _rtld_error("sysctl for hw.pagesize(s) failed"); 2160 rtld_die(); 2161 } 2162 psa_filled: 2163 pagesizes = psa; 2164 } 2165 npagesizes = size / sizeof(pagesizes[0]); 2166 /* Discard any invalid entries at the end of the array. */ 2167 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2168 npagesizes--; 2169 } 2170 2171 /* 2172 * Add the init functions from a needed object list (and its recursive 2173 * needed objects) to "list". This is not used directly; it is a helper 2174 * function for initlist_add_objects(). The write lock must be held 2175 * when this function is called. 2176 */ 2177 static void 2178 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2179 { 2180 /* Recursively process the successor needed objects. */ 2181 if (needed->next != NULL) 2182 initlist_add_neededs(needed->next, list); 2183 2184 /* Process the current needed object. */ 2185 if (needed->obj != NULL) 2186 initlist_add_objects(needed->obj, needed->obj, list); 2187 } 2188 2189 /* 2190 * Scan all of the DAGs rooted in the range of objects from "obj" to 2191 * "tail" and add their init functions to "list". This recurses over 2192 * the DAGs and ensure the proper init ordering such that each object's 2193 * needed libraries are initialized before the object itself. At the 2194 * same time, this function adds the objects to the global finalization 2195 * list "list_fini" in the opposite order. The write lock must be 2196 * held when this function is called. 2197 */ 2198 static void 2199 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2200 { 2201 Obj_Entry *nobj; 2202 2203 if (obj->init_scanned || obj->init_done) 2204 return; 2205 obj->init_scanned = true; 2206 2207 /* Recursively process the successor objects. */ 2208 nobj = globallist_next(obj); 2209 if (nobj != NULL && obj != tail) 2210 initlist_add_objects(nobj, tail, list); 2211 2212 /* Recursively process the needed objects. */ 2213 if (obj->needed != NULL) 2214 initlist_add_neededs(obj->needed, list); 2215 if (obj->needed_filtees != NULL) 2216 initlist_add_neededs(obj->needed_filtees, list); 2217 if (obj->needed_aux_filtees != NULL) 2218 initlist_add_neededs(obj->needed_aux_filtees, list); 2219 2220 /* Add the object to the init list. */ 2221 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2222 obj->init_array != (Elf_Addr)NULL) 2223 objlist_push_tail(list, obj); 2224 2225 /* Add the object to the global fini list in the reverse order. */ 2226 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2227 && !obj->on_fini_list) { 2228 objlist_push_head(&list_fini, obj); 2229 obj->on_fini_list = true; 2230 } 2231 } 2232 2233 #ifndef FPTR_TARGET 2234 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2235 #endif 2236 2237 static void 2238 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2239 { 2240 Needed_Entry *needed, *needed1; 2241 2242 for (needed = n; needed != NULL; needed = needed->next) { 2243 if (needed->obj != NULL) { 2244 dlclose_locked(needed->obj, lockstate); 2245 needed->obj = NULL; 2246 } 2247 } 2248 for (needed = n; needed != NULL; needed = needed1) { 2249 needed1 = needed->next; 2250 free(needed); 2251 } 2252 } 2253 2254 static void 2255 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2256 { 2257 2258 free_needed_filtees(obj->needed_filtees, lockstate); 2259 obj->needed_filtees = NULL; 2260 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2261 obj->needed_aux_filtees = NULL; 2262 obj->filtees_loaded = false; 2263 } 2264 2265 static void 2266 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2267 RtldLockState *lockstate) 2268 { 2269 2270 for (; needed != NULL; needed = needed->next) { 2271 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2272 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2273 RTLD_LOCAL, lockstate); 2274 } 2275 } 2276 2277 static void 2278 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2279 { 2280 2281 lock_restart_for_upgrade(lockstate); 2282 if (!obj->filtees_loaded) { 2283 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2284 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2285 obj->filtees_loaded = true; 2286 } 2287 } 2288 2289 static int 2290 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2291 { 2292 Obj_Entry *obj1; 2293 2294 for (; needed != NULL; needed = needed->next) { 2295 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2296 flags & ~RTLD_LO_NOLOAD); 2297 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2298 return (-1); 2299 } 2300 return (0); 2301 } 2302 2303 /* 2304 * Given a shared object, traverse its list of needed objects, and load 2305 * each of them. Returns 0 on success. Generates an error message and 2306 * returns -1 on failure. 2307 */ 2308 static int 2309 load_needed_objects(Obj_Entry *first, int flags) 2310 { 2311 Obj_Entry *obj; 2312 2313 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2314 if (obj->marker) 2315 continue; 2316 if (process_needed(obj, obj->needed, flags) == -1) 2317 return (-1); 2318 } 2319 return (0); 2320 } 2321 2322 static int 2323 load_preload_objects(void) 2324 { 2325 char *p = ld_preload; 2326 Obj_Entry *obj; 2327 static const char delim[] = " \t:;"; 2328 2329 if (p == NULL) 2330 return 0; 2331 2332 p += strspn(p, delim); 2333 while (*p != '\0') { 2334 size_t len = strcspn(p, delim); 2335 char savech; 2336 2337 savech = p[len]; 2338 p[len] = '\0'; 2339 obj = load_object(p, -1, NULL, 0); 2340 if (obj == NULL) 2341 return -1; /* XXX - cleanup */ 2342 obj->z_interpose = true; 2343 p[len] = savech; 2344 p += len; 2345 p += strspn(p, delim); 2346 } 2347 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2348 return 0; 2349 } 2350 2351 static const char * 2352 printable_path(const char *path) 2353 { 2354 2355 return (path == NULL ? "<unknown>" : path); 2356 } 2357 2358 /* 2359 * Load a shared object into memory, if it is not already loaded. The 2360 * object may be specified by name or by user-supplied file descriptor 2361 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2362 * duplicate is. 2363 * 2364 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2365 * on failure. 2366 */ 2367 static Obj_Entry * 2368 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2369 { 2370 Obj_Entry *obj; 2371 int fd; 2372 struct stat sb; 2373 char *path; 2374 2375 fd = -1; 2376 if (name != NULL) { 2377 TAILQ_FOREACH(obj, &obj_list, next) { 2378 if (obj->marker || obj->doomed) 2379 continue; 2380 if (object_match_name(obj, name)) 2381 return (obj); 2382 } 2383 2384 path = find_library(name, refobj, &fd); 2385 if (path == NULL) 2386 return (NULL); 2387 } else 2388 path = NULL; 2389 2390 if (fd >= 0) { 2391 /* 2392 * search_library_pathfds() opens a fresh file descriptor for the 2393 * library, so there is no need to dup(). 2394 */ 2395 } else if (fd_u == -1) { 2396 /* 2397 * If we didn't find a match by pathname, or the name is not 2398 * supplied, open the file and check again by device and inode. 2399 * This avoids false mismatches caused by multiple links or ".." 2400 * in pathnames. 2401 * 2402 * To avoid a race, we open the file and use fstat() rather than 2403 * using stat(). 2404 */ 2405 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2406 _rtld_error("Cannot open \"%s\"", path); 2407 free(path); 2408 return (NULL); 2409 } 2410 } else { 2411 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2412 if (fd == -1) { 2413 _rtld_error("Cannot dup fd"); 2414 free(path); 2415 return (NULL); 2416 } 2417 } 2418 if (fstat(fd, &sb) == -1) { 2419 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2420 close(fd); 2421 free(path); 2422 return NULL; 2423 } 2424 TAILQ_FOREACH(obj, &obj_list, next) { 2425 if (obj->marker || obj->doomed) 2426 continue; 2427 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2428 break; 2429 } 2430 if (obj != NULL && name != NULL) { 2431 object_add_name(obj, name); 2432 free(path); 2433 close(fd); 2434 return obj; 2435 } 2436 if (flags & RTLD_LO_NOLOAD) { 2437 free(path); 2438 close(fd); 2439 return (NULL); 2440 } 2441 2442 /* First use of this object, so we must map it in */ 2443 obj = do_load_object(fd, name, path, &sb, flags); 2444 if (obj == NULL) 2445 free(path); 2446 close(fd); 2447 2448 return obj; 2449 } 2450 2451 static Obj_Entry * 2452 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2453 int flags) 2454 { 2455 Obj_Entry *obj; 2456 struct statfs fs; 2457 2458 /* 2459 * but first, make sure that environment variables haven't been 2460 * used to circumvent the noexec flag on a filesystem. 2461 */ 2462 if (dangerous_ld_env) { 2463 if (fstatfs(fd, &fs) != 0) { 2464 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2465 return NULL; 2466 } 2467 if (fs.f_flags & MNT_NOEXEC) { 2468 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2469 return NULL; 2470 } 2471 } 2472 dbg("loading \"%s\"", printable_path(path)); 2473 obj = map_object(fd, printable_path(path), sbp); 2474 if (obj == NULL) 2475 return NULL; 2476 2477 /* 2478 * If DT_SONAME is present in the object, digest_dynamic2 already 2479 * added it to the object names. 2480 */ 2481 if (name != NULL) 2482 object_add_name(obj, name); 2483 obj->path = path; 2484 digest_dynamic(obj, 0); 2485 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2486 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2487 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2488 RTLD_LO_DLOPEN) { 2489 dbg("refusing to load non-loadable \"%s\"", obj->path); 2490 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2491 munmap(obj->mapbase, obj->mapsize); 2492 obj_free(obj); 2493 return (NULL); 2494 } 2495 2496 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2497 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2498 obj_count++; 2499 obj_loads++; 2500 linkmap_add(obj); /* for GDB & dlinfo() */ 2501 max_stack_flags |= obj->stack_flags; 2502 2503 dbg(" %p .. %p: %s", obj->mapbase, 2504 obj->mapbase + obj->mapsize - 1, obj->path); 2505 if (obj->textrel) 2506 dbg(" WARNING: %s has impure text", obj->path); 2507 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2508 obj->path); 2509 2510 return obj; 2511 } 2512 2513 static Obj_Entry * 2514 obj_from_addr(const void *addr) 2515 { 2516 Obj_Entry *obj; 2517 2518 TAILQ_FOREACH(obj, &obj_list, next) { 2519 if (obj->marker) 2520 continue; 2521 if (addr < (void *) obj->mapbase) 2522 continue; 2523 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2524 return obj; 2525 } 2526 return NULL; 2527 } 2528 2529 static void 2530 preinit_main(void) 2531 { 2532 Elf_Addr *preinit_addr; 2533 int index; 2534 2535 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2536 if (preinit_addr == NULL) 2537 return; 2538 2539 for (index = 0; index < obj_main->preinit_array_num; index++) { 2540 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2541 dbg("calling preinit function for %s at %p", obj_main->path, 2542 (void *)preinit_addr[index]); 2543 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2544 0, 0, obj_main->path); 2545 call_init_pointer(obj_main, preinit_addr[index]); 2546 } 2547 } 2548 } 2549 2550 /* 2551 * Call the finalization functions for each of the objects in "list" 2552 * belonging to the DAG of "root" and referenced once. If NULL "root" 2553 * is specified, every finalization function will be called regardless 2554 * of the reference count and the list elements won't be freed. All of 2555 * the objects are expected to have non-NULL fini functions. 2556 */ 2557 static void 2558 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2559 { 2560 Objlist_Entry *elm; 2561 char *saved_msg; 2562 Elf_Addr *fini_addr; 2563 int index; 2564 2565 assert(root == NULL || root->refcount == 1); 2566 2567 if (root != NULL) 2568 root->doomed = true; 2569 2570 /* 2571 * Preserve the current error message since a fini function might 2572 * call into the dynamic linker and overwrite it. 2573 */ 2574 saved_msg = errmsg_save(); 2575 do { 2576 STAILQ_FOREACH(elm, list, link) { 2577 if (root != NULL && (elm->obj->refcount != 1 || 2578 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2579 continue; 2580 /* Remove object from fini list to prevent recursive invocation. */ 2581 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2582 /* Ensure that new references cannot be acquired. */ 2583 elm->obj->doomed = true; 2584 2585 hold_object(elm->obj); 2586 lock_release(rtld_bind_lock, lockstate); 2587 /* 2588 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2589 * When this happens, DT_FINI_ARRAY is processed first. 2590 */ 2591 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2592 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2593 for (index = elm->obj->fini_array_num - 1; index >= 0; 2594 index--) { 2595 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2596 dbg("calling fini function for %s at %p", 2597 elm->obj->path, (void *)fini_addr[index]); 2598 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2599 (void *)fini_addr[index], 0, 0, elm->obj->path); 2600 call_initfini_pointer(elm->obj, fini_addr[index]); 2601 } 2602 } 2603 } 2604 if (elm->obj->fini != (Elf_Addr)NULL) { 2605 dbg("calling fini function for %s at %p", elm->obj->path, 2606 (void *)elm->obj->fini); 2607 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2608 0, 0, elm->obj->path); 2609 call_initfini_pointer(elm->obj, elm->obj->fini); 2610 } 2611 wlock_acquire(rtld_bind_lock, lockstate); 2612 unhold_object(elm->obj); 2613 /* No need to free anything if process is going down. */ 2614 if (root != NULL) 2615 free(elm); 2616 /* 2617 * We must restart the list traversal after every fini call 2618 * because a dlclose() call from the fini function or from 2619 * another thread might have modified the reference counts. 2620 */ 2621 break; 2622 } 2623 } while (elm != NULL); 2624 errmsg_restore(saved_msg); 2625 } 2626 2627 /* 2628 * Call the initialization functions for each of the objects in 2629 * "list". All of the objects are expected to have non-NULL init 2630 * functions. 2631 */ 2632 static void 2633 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2634 { 2635 Objlist_Entry *elm; 2636 Obj_Entry *obj; 2637 char *saved_msg; 2638 Elf_Addr *init_addr; 2639 int index; 2640 2641 /* 2642 * Clean init_scanned flag so that objects can be rechecked and 2643 * possibly initialized earlier if any of vectors called below 2644 * cause the change by using dlopen. 2645 */ 2646 TAILQ_FOREACH(obj, &obj_list, next) { 2647 if (obj->marker) 2648 continue; 2649 obj->init_scanned = false; 2650 } 2651 2652 /* 2653 * Preserve the current error message since an init function might 2654 * call into the dynamic linker and overwrite it. 2655 */ 2656 saved_msg = errmsg_save(); 2657 STAILQ_FOREACH(elm, list, link) { 2658 if (elm->obj->init_done) /* Initialized early. */ 2659 continue; 2660 /* 2661 * Race: other thread might try to use this object before current 2662 * one completes the initialization. Not much can be done here 2663 * without better locking. 2664 */ 2665 elm->obj->init_done = true; 2666 hold_object(elm->obj); 2667 lock_release(rtld_bind_lock, lockstate); 2668 2669 /* 2670 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2671 * When this happens, DT_INIT is processed first. 2672 */ 2673 if (elm->obj->init != (Elf_Addr)NULL) { 2674 dbg("calling init function for %s at %p", elm->obj->path, 2675 (void *)elm->obj->init); 2676 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2677 0, 0, elm->obj->path); 2678 call_initfini_pointer(elm->obj, elm->obj->init); 2679 } 2680 init_addr = (Elf_Addr *)elm->obj->init_array; 2681 if (init_addr != NULL) { 2682 for (index = 0; index < elm->obj->init_array_num; index++) { 2683 if (init_addr[index] != 0 && init_addr[index] != 1) { 2684 dbg("calling init function for %s at %p", elm->obj->path, 2685 (void *)init_addr[index]); 2686 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2687 (void *)init_addr[index], 0, 0, elm->obj->path); 2688 call_init_pointer(elm->obj, init_addr[index]); 2689 } 2690 } 2691 } 2692 wlock_acquire(rtld_bind_lock, lockstate); 2693 unhold_object(elm->obj); 2694 } 2695 errmsg_restore(saved_msg); 2696 } 2697 2698 static void 2699 objlist_clear(Objlist *list) 2700 { 2701 Objlist_Entry *elm; 2702 2703 while (!STAILQ_EMPTY(list)) { 2704 elm = STAILQ_FIRST(list); 2705 STAILQ_REMOVE_HEAD(list, link); 2706 free(elm); 2707 } 2708 } 2709 2710 static Objlist_Entry * 2711 objlist_find(Objlist *list, const Obj_Entry *obj) 2712 { 2713 Objlist_Entry *elm; 2714 2715 STAILQ_FOREACH(elm, list, link) 2716 if (elm->obj == obj) 2717 return elm; 2718 return NULL; 2719 } 2720 2721 static void 2722 objlist_init(Objlist *list) 2723 { 2724 STAILQ_INIT(list); 2725 } 2726 2727 static void 2728 objlist_push_head(Objlist *list, Obj_Entry *obj) 2729 { 2730 Objlist_Entry *elm; 2731 2732 elm = NEW(Objlist_Entry); 2733 elm->obj = obj; 2734 STAILQ_INSERT_HEAD(list, elm, link); 2735 } 2736 2737 static void 2738 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2739 { 2740 Objlist_Entry *elm; 2741 2742 elm = NEW(Objlist_Entry); 2743 elm->obj = obj; 2744 STAILQ_INSERT_TAIL(list, elm, link); 2745 } 2746 2747 static void 2748 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2749 { 2750 Objlist_Entry *elm, *listelm; 2751 2752 STAILQ_FOREACH(listelm, list, link) { 2753 if (listelm->obj == listobj) 2754 break; 2755 } 2756 elm = NEW(Objlist_Entry); 2757 elm->obj = obj; 2758 if (listelm != NULL) 2759 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2760 else 2761 STAILQ_INSERT_TAIL(list, elm, link); 2762 } 2763 2764 static void 2765 objlist_remove(Objlist *list, Obj_Entry *obj) 2766 { 2767 Objlist_Entry *elm; 2768 2769 if ((elm = objlist_find(list, obj)) != NULL) { 2770 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2771 free(elm); 2772 } 2773 } 2774 2775 /* 2776 * Relocate dag rooted in the specified object. 2777 * Returns 0 on success, or -1 on failure. 2778 */ 2779 2780 static int 2781 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2782 int flags, RtldLockState *lockstate) 2783 { 2784 Objlist_Entry *elm; 2785 int error; 2786 2787 error = 0; 2788 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2789 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2790 lockstate); 2791 if (error == -1) 2792 break; 2793 } 2794 return (error); 2795 } 2796 2797 /* 2798 * Prepare for, or clean after, relocating an object marked with 2799 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2800 * segments are remapped read-write. After relocations are done, the 2801 * segment's permissions are returned back to the modes specified in 2802 * the phdrs. If any relocation happened, or always for wired 2803 * program, COW is triggered. 2804 */ 2805 static int 2806 reloc_textrel_prot(Obj_Entry *obj, bool before) 2807 { 2808 const Elf_Phdr *ph; 2809 void *base; 2810 size_t l, sz; 2811 int prot; 2812 2813 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2814 l--, ph++) { 2815 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2816 continue; 2817 base = obj->relocbase + trunc_page(ph->p_vaddr); 2818 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2819 trunc_page(ph->p_vaddr); 2820 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2821 if (mprotect(base, sz, prot) == -1) { 2822 _rtld_error("%s: Cannot write-%sable text segment: %s", 2823 obj->path, before ? "en" : "dis", 2824 rtld_strerror(errno)); 2825 return (-1); 2826 } 2827 } 2828 return (0); 2829 } 2830 2831 /* 2832 * Relocate single object. 2833 * Returns 0 on success, or -1 on failure. 2834 */ 2835 static int 2836 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2837 int flags, RtldLockState *lockstate) 2838 { 2839 2840 if (obj->relocated) 2841 return (0); 2842 obj->relocated = true; 2843 if (obj != rtldobj) 2844 dbg("relocating \"%s\"", obj->path); 2845 2846 if (obj->symtab == NULL || obj->strtab == NULL || 2847 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2848 _rtld_error("%s: Shared object has no run-time symbol table", 2849 obj->path); 2850 return (-1); 2851 } 2852 2853 /* There are relocations to the write-protected text segment. */ 2854 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2855 return (-1); 2856 2857 /* Process the non-PLT non-IFUNC relocations. */ 2858 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2859 return (-1); 2860 2861 /* Re-protected the text segment. */ 2862 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2863 return (-1); 2864 2865 /* Set the special PLT or GOT entries. */ 2866 init_pltgot(obj); 2867 2868 /* Process the PLT relocations. */ 2869 if (reloc_plt(obj) == -1) 2870 return (-1); 2871 /* Relocate the jump slots if we are doing immediate binding. */ 2872 if (obj->bind_now || bind_now) 2873 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2874 return (-1); 2875 2876 /* 2877 * Process the non-PLT IFUNC relocations. The relocations are 2878 * processed in two phases, because IFUNC resolvers may 2879 * reference other symbols, which must be readily processed 2880 * before resolvers are called. 2881 */ 2882 if (obj->non_plt_gnu_ifunc && 2883 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2884 return (-1); 2885 2886 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2887 return (-1); 2888 2889 /* 2890 * Set up the magic number and version in the Obj_Entry. These 2891 * were checked in the crt1.o from the original ElfKit, so we 2892 * set them for backward compatibility. 2893 */ 2894 obj->magic = RTLD_MAGIC; 2895 obj->version = RTLD_VERSION; 2896 2897 return (0); 2898 } 2899 2900 /* 2901 * Relocate newly-loaded shared objects. The argument is a pointer to 2902 * the Obj_Entry for the first such object. All objects from the first 2903 * to the end of the list of objects are relocated. Returns 0 on success, 2904 * or -1 on failure. 2905 */ 2906 static int 2907 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2908 int flags, RtldLockState *lockstate) 2909 { 2910 Obj_Entry *obj; 2911 int error; 2912 2913 for (error = 0, obj = first; obj != NULL; 2914 obj = TAILQ_NEXT(obj, next)) { 2915 if (obj->marker) 2916 continue; 2917 error = relocate_object(obj, bind_now, rtldobj, flags, 2918 lockstate); 2919 if (error == -1) 2920 break; 2921 } 2922 return (error); 2923 } 2924 2925 /* 2926 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2927 * referencing STT_GNU_IFUNC symbols is postponed till the other 2928 * relocations are done. The indirect functions specified as 2929 * ifunc are allowed to call other symbols, so we need to have 2930 * objects relocated before asking for resolution from indirects. 2931 * 2932 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2933 * instead of the usual lazy handling of PLT slots. It is 2934 * consistent with how GNU does it. 2935 */ 2936 static int 2937 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2938 RtldLockState *lockstate) 2939 { 2940 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2941 return (-1); 2942 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2943 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2944 return (-1); 2945 return (0); 2946 } 2947 2948 static int 2949 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2950 RtldLockState *lockstate) 2951 { 2952 Obj_Entry *obj; 2953 2954 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2955 if (obj->marker) 2956 continue; 2957 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2958 return (-1); 2959 } 2960 return (0); 2961 } 2962 2963 static int 2964 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2965 RtldLockState *lockstate) 2966 { 2967 Objlist_Entry *elm; 2968 2969 STAILQ_FOREACH(elm, list, link) { 2970 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2971 lockstate) == -1) 2972 return (-1); 2973 } 2974 return (0); 2975 } 2976 2977 /* 2978 * Cleanup procedure. It will be called (by the atexit mechanism) just 2979 * before the process exits. 2980 */ 2981 static void 2982 rtld_exit(void) 2983 { 2984 RtldLockState lockstate; 2985 2986 wlock_acquire(rtld_bind_lock, &lockstate); 2987 dbg("rtld_exit()"); 2988 objlist_call_fini(&list_fini, NULL, &lockstate); 2989 /* No need to remove the items from the list, since we are exiting. */ 2990 if (!libmap_disable) 2991 lm_fini(); 2992 lock_release(rtld_bind_lock, &lockstate); 2993 } 2994 2995 /* 2996 * Iterate over a search path, translate each element, and invoke the 2997 * callback on the result. 2998 */ 2999 static void * 3000 path_enumerate(const char *path, path_enum_proc callback, void *arg) 3001 { 3002 const char *trans; 3003 if (path == NULL) 3004 return (NULL); 3005 3006 path += strspn(path, ":;"); 3007 while (*path != '\0') { 3008 size_t len; 3009 char *res; 3010 3011 len = strcspn(path, ":;"); 3012 trans = lm_findn(NULL, path, len); 3013 if (trans) 3014 res = callback(trans, strlen(trans), arg); 3015 else 3016 res = callback(path, len, arg); 3017 3018 if (res != NULL) 3019 return (res); 3020 3021 path += len; 3022 path += strspn(path, ":;"); 3023 } 3024 3025 return (NULL); 3026 } 3027 3028 struct try_library_args { 3029 const char *name; 3030 size_t namelen; 3031 char *buffer; 3032 size_t buflen; 3033 int fd; 3034 }; 3035 3036 static void * 3037 try_library_path(const char *dir, size_t dirlen, void *param) 3038 { 3039 struct try_library_args *arg; 3040 int fd; 3041 3042 arg = param; 3043 if (*dir == '/' || trust) { 3044 char *pathname; 3045 3046 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3047 return (NULL); 3048 3049 pathname = arg->buffer; 3050 strncpy(pathname, dir, dirlen); 3051 pathname[dirlen] = '/'; 3052 strcpy(pathname + dirlen + 1, arg->name); 3053 3054 dbg(" Trying \"%s\"", pathname); 3055 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3056 if (fd >= 0) { 3057 dbg(" Opened \"%s\", fd %d", pathname, fd); 3058 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3059 strcpy(pathname, arg->buffer); 3060 arg->fd = fd; 3061 return (pathname); 3062 } else { 3063 dbg(" Failed to open \"%s\": %s", 3064 pathname, rtld_strerror(errno)); 3065 } 3066 } 3067 return (NULL); 3068 } 3069 3070 static char * 3071 search_library_path(const char *name, const char *path, int *fdp) 3072 { 3073 char *p; 3074 struct try_library_args arg; 3075 3076 if (path == NULL) 3077 return NULL; 3078 3079 arg.name = name; 3080 arg.namelen = strlen(name); 3081 arg.buffer = xmalloc(PATH_MAX); 3082 arg.buflen = PATH_MAX; 3083 arg.fd = -1; 3084 3085 p = path_enumerate(path, try_library_path, &arg); 3086 *fdp = arg.fd; 3087 3088 free(arg.buffer); 3089 3090 return (p); 3091 } 3092 3093 3094 /* 3095 * Finds the library with the given name using the directory descriptors 3096 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3097 * 3098 * Returns a freshly-opened close-on-exec file descriptor for the library, 3099 * or -1 if the library cannot be found. 3100 */ 3101 static char * 3102 search_library_pathfds(const char *name, const char *path, int *fdp) 3103 { 3104 char *envcopy, *fdstr, *found, *last_token; 3105 size_t len; 3106 int dirfd, fd; 3107 3108 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3109 3110 /* Don't load from user-specified libdirs into setuid binaries. */ 3111 if (!trust) 3112 return (NULL); 3113 3114 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3115 if (path == NULL) 3116 return (NULL); 3117 3118 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3119 if (name[0] == '/') { 3120 dbg("Absolute path (%s) passed to %s", name, __func__); 3121 return (NULL); 3122 } 3123 3124 /* 3125 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3126 * copy of the path, as strtok_r rewrites separator tokens 3127 * with '\0'. 3128 */ 3129 found = NULL; 3130 envcopy = xstrdup(path); 3131 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3132 fdstr = strtok_r(NULL, ":", &last_token)) { 3133 dirfd = parse_integer(fdstr); 3134 if (dirfd < 0) { 3135 _rtld_error("failed to parse directory FD: '%s'", 3136 fdstr); 3137 break; 3138 } 3139 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3140 if (fd >= 0) { 3141 *fdp = fd; 3142 len = strlen(fdstr) + strlen(name) + 3; 3143 found = xmalloc(len); 3144 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3145 _rtld_error("error generating '%d/%s'", 3146 dirfd, name); 3147 rtld_die(); 3148 } 3149 dbg("open('%s') => %d", found, fd); 3150 break; 3151 } 3152 } 3153 free(envcopy); 3154 3155 return (found); 3156 } 3157 3158 3159 int 3160 dlclose(void *handle) 3161 { 3162 RtldLockState lockstate; 3163 int error; 3164 3165 wlock_acquire(rtld_bind_lock, &lockstate); 3166 error = dlclose_locked(handle, &lockstate); 3167 lock_release(rtld_bind_lock, &lockstate); 3168 return (error); 3169 } 3170 3171 static int 3172 dlclose_locked(void *handle, RtldLockState *lockstate) 3173 { 3174 Obj_Entry *root; 3175 3176 root = dlcheck(handle); 3177 if (root == NULL) 3178 return -1; 3179 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3180 root->path); 3181 3182 /* Unreference the object and its dependencies. */ 3183 root->dl_refcount--; 3184 3185 if (root->refcount == 1) { 3186 /* 3187 * The object will be no longer referenced, so we must unload it. 3188 * First, call the fini functions. 3189 */ 3190 objlist_call_fini(&list_fini, root, lockstate); 3191 3192 unref_dag(root); 3193 3194 /* Finish cleaning up the newly-unreferenced objects. */ 3195 GDB_STATE(RT_DELETE,&root->linkmap); 3196 unload_object(root, lockstate); 3197 GDB_STATE(RT_CONSISTENT,NULL); 3198 } else 3199 unref_dag(root); 3200 3201 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3202 return 0; 3203 } 3204 3205 char * 3206 dlerror(void) 3207 { 3208 char *msg = error_message; 3209 error_message = NULL; 3210 return msg; 3211 } 3212 3213 /* 3214 * This function is deprecated and has no effect. 3215 */ 3216 void 3217 dllockinit(void *context, 3218 void *(*lock_create)(void *context), 3219 void (*rlock_acquire)(void *lock), 3220 void (*wlock_acquire)(void *lock), 3221 void (*lock_release)(void *lock), 3222 void (*lock_destroy)(void *lock), 3223 void (*context_destroy)(void *context)) 3224 { 3225 static void *cur_context; 3226 static void (*cur_context_destroy)(void *); 3227 3228 /* Just destroy the context from the previous call, if necessary. */ 3229 if (cur_context_destroy != NULL) 3230 cur_context_destroy(cur_context); 3231 cur_context = context; 3232 cur_context_destroy = context_destroy; 3233 } 3234 3235 void * 3236 dlopen(const char *name, int mode) 3237 { 3238 3239 return (rtld_dlopen(name, -1, mode)); 3240 } 3241 3242 void * 3243 fdlopen(int fd, int mode) 3244 { 3245 3246 return (rtld_dlopen(NULL, fd, mode)); 3247 } 3248 3249 static void * 3250 rtld_dlopen(const char *name, int fd, int mode) 3251 { 3252 RtldLockState lockstate; 3253 int lo_flags; 3254 3255 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3256 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3257 if (ld_tracing != NULL) { 3258 rlock_acquire(rtld_bind_lock, &lockstate); 3259 if (sigsetjmp(lockstate.env, 0) != 0) 3260 lock_upgrade(rtld_bind_lock, &lockstate); 3261 environ = (char **)*get_program_var_addr("environ", &lockstate); 3262 lock_release(rtld_bind_lock, &lockstate); 3263 } 3264 lo_flags = RTLD_LO_DLOPEN; 3265 if (mode & RTLD_NODELETE) 3266 lo_flags |= RTLD_LO_NODELETE; 3267 if (mode & RTLD_NOLOAD) 3268 lo_flags |= RTLD_LO_NOLOAD; 3269 if (ld_tracing != NULL) 3270 lo_flags |= RTLD_LO_TRACE; 3271 3272 return (dlopen_object(name, fd, obj_main, lo_flags, 3273 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3274 } 3275 3276 static void 3277 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3278 { 3279 3280 obj->dl_refcount--; 3281 unref_dag(obj); 3282 if (obj->refcount == 0) 3283 unload_object(obj, lockstate); 3284 } 3285 3286 static Obj_Entry * 3287 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3288 int mode, RtldLockState *lockstate) 3289 { 3290 Obj_Entry *old_obj_tail; 3291 Obj_Entry *obj; 3292 Objlist initlist; 3293 RtldLockState mlockstate; 3294 int result; 3295 3296 objlist_init(&initlist); 3297 3298 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3299 wlock_acquire(rtld_bind_lock, &mlockstate); 3300 lockstate = &mlockstate; 3301 } 3302 GDB_STATE(RT_ADD,NULL); 3303 3304 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3305 obj = NULL; 3306 if (name == NULL && fd == -1) { 3307 obj = obj_main; 3308 obj->refcount++; 3309 } else { 3310 obj = load_object(name, fd, refobj, lo_flags); 3311 } 3312 3313 if (obj) { 3314 obj->dl_refcount++; 3315 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3316 objlist_push_tail(&list_global, obj); 3317 if (globallist_next(old_obj_tail) != NULL) { 3318 /* We loaded something new. */ 3319 assert(globallist_next(old_obj_tail) == obj); 3320 result = load_needed_objects(obj, 3321 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3322 init_dag(obj); 3323 ref_dag(obj); 3324 if (result != -1) 3325 result = rtld_verify_versions(&obj->dagmembers); 3326 if (result != -1 && ld_tracing) 3327 goto trace; 3328 if (result == -1 || relocate_object_dag(obj, 3329 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3330 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3331 lockstate) == -1) { 3332 dlopen_cleanup(obj, lockstate); 3333 obj = NULL; 3334 } else if (lo_flags & RTLD_LO_EARLY) { 3335 /* 3336 * Do not call the init functions for early loaded 3337 * filtees. The image is still not initialized enough 3338 * for them to work. 3339 * 3340 * Our object is found by the global object list and 3341 * will be ordered among all init calls done right 3342 * before transferring control to main. 3343 */ 3344 } else { 3345 /* Make list of init functions to call. */ 3346 initlist_add_objects(obj, obj, &initlist); 3347 } 3348 /* 3349 * Process all no_delete or global objects here, given 3350 * them own DAGs to prevent their dependencies from being 3351 * unloaded. This has to be done after we have loaded all 3352 * of the dependencies, so that we do not miss any. 3353 */ 3354 if (obj != NULL) 3355 process_z(obj); 3356 } else { 3357 /* 3358 * Bump the reference counts for objects on this DAG. If 3359 * this is the first dlopen() call for the object that was 3360 * already loaded as a dependency, initialize the dag 3361 * starting at it. 3362 */ 3363 init_dag(obj); 3364 ref_dag(obj); 3365 3366 if ((lo_flags & RTLD_LO_TRACE) != 0) 3367 goto trace; 3368 } 3369 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3370 obj->z_nodelete) && !obj->ref_nodel) { 3371 dbg("obj %s nodelete", obj->path); 3372 ref_dag(obj); 3373 obj->z_nodelete = obj->ref_nodel = true; 3374 } 3375 } 3376 3377 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3378 name); 3379 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3380 3381 if (!(lo_flags & RTLD_LO_EARLY)) { 3382 map_stacks_exec(lockstate); 3383 } 3384 3385 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3386 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3387 lockstate) == -1) { 3388 objlist_clear(&initlist); 3389 dlopen_cleanup(obj, lockstate); 3390 if (lockstate == &mlockstate) 3391 lock_release(rtld_bind_lock, lockstate); 3392 return (NULL); 3393 } 3394 3395 if (!(lo_flags & RTLD_LO_EARLY)) { 3396 /* Call the init functions. */ 3397 objlist_call_init(&initlist, lockstate); 3398 } 3399 objlist_clear(&initlist); 3400 if (lockstate == &mlockstate) 3401 lock_release(rtld_bind_lock, lockstate); 3402 return obj; 3403 trace: 3404 trace_loaded_objects(obj); 3405 if (lockstate == &mlockstate) 3406 lock_release(rtld_bind_lock, lockstate); 3407 exit(0); 3408 } 3409 3410 static void * 3411 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3412 int flags) 3413 { 3414 DoneList donelist; 3415 const Obj_Entry *obj, *defobj; 3416 const Elf_Sym *def; 3417 SymLook req; 3418 RtldLockState lockstate; 3419 tls_index ti; 3420 void *sym; 3421 int res; 3422 3423 def = NULL; 3424 defobj = NULL; 3425 symlook_init(&req, name); 3426 req.ventry = ve; 3427 req.flags = flags | SYMLOOK_IN_PLT; 3428 req.lockstate = &lockstate; 3429 3430 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3431 rlock_acquire(rtld_bind_lock, &lockstate); 3432 if (sigsetjmp(lockstate.env, 0) != 0) 3433 lock_upgrade(rtld_bind_lock, &lockstate); 3434 if (handle == NULL || handle == RTLD_NEXT || 3435 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3436 3437 if ((obj = obj_from_addr(retaddr)) == NULL) { 3438 _rtld_error("Cannot determine caller's shared object"); 3439 lock_release(rtld_bind_lock, &lockstate); 3440 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3441 return NULL; 3442 } 3443 if (handle == NULL) { /* Just the caller's shared object. */ 3444 res = symlook_obj(&req, obj); 3445 if (res == 0) { 3446 def = req.sym_out; 3447 defobj = req.defobj_out; 3448 } 3449 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3450 handle == RTLD_SELF) { /* ... caller included */ 3451 if (handle == RTLD_NEXT) 3452 obj = globallist_next(obj); 3453 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3454 if (obj->marker) 3455 continue; 3456 res = symlook_obj(&req, obj); 3457 if (res == 0) { 3458 if (def == NULL || 3459 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3460 def = req.sym_out; 3461 defobj = req.defobj_out; 3462 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3463 break; 3464 } 3465 } 3466 } 3467 /* 3468 * Search the dynamic linker itself, and possibly resolve the 3469 * symbol from there. This is how the application links to 3470 * dynamic linker services such as dlopen. 3471 */ 3472 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3473 res = symlook_obj(&req, &obj_rtld); 3474 if (res == 0) { 3475 def = req.sym_out; 3476 defobj = req.defobj_out; 3477 } 3478 } 3479 } else { 3480 assert(handle == RTLD_DEFAULT); 3481 res = symlook_default(&req, obj); 3482 if (res == 0) { 3483 defobj = req.defobj_out; 3484 def = req.sym_out; 3485 } 3486 } 3487 } else { 3488 if ((obj = dlcheck(handle)) == NULL) { 3489 lock_release(rtld_bind_lock, &lockstate); 3490 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3491 return NULL; 3492 } 3493 3494 donelist_init(&donelist); 3495 if (obj->mainprog) { 3496 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3497 res = symlook_global(&req, &donelist); 3498 if (res == 0) { 3499 def = req.sym_out; 3500 defobj = req.defobj_out; 3501 } 3502 /* 3503 * Search the dynamic linker itself, and possibly resolve the 3504 * symbol from there. This is how the application links to 3505 * dynamic linker services such as dlopen. 3506 */ 3507 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3508 res = symlook_obj(&req, &obj_rtld); 3509 if (res == 0) { 3510 def = req.sym_out; 3511 defobj = req.defobj_out; 3512 } 3513 } 3514 } 3515 else { 3516 /* Search the whole DAG rooted at the given object. */ 3517 res = symlook_list(&req, &obj->dagmembers, &donelist); 3518 if (res == 0) { 3519 def = req.sym_out; 3520 defobj = req.defobj_out; 3521 } 3522 } 3523 } 3524 3525 if (def != NULL) { 3526 lock_release(rtld_bind_lock, &lockstate); 3527 3528 /* 3529 * The value required by the caller is derived from the value 3530 * of the symbol. this is simply the relocated value of the 3531 * symbol. 3532 */ 3533 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3534 sym = make_function_pointer(def, defobj); 3535 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3536 sym = rtld_resolve_ifunc(defobj, def); 3537 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3538 ti.ti_module = defobj->tlsindex; 3539 ti.ti_offset = def->st_value; 3540 sym = __tls_get_addr(&ti); 3541 } else 3542 sym = defobj->relocbase + def->st_value; 3543 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3544 return (sym); 3545 } 3546 3547 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3548 ve != NULL ? ve->name : ""); 3549 lock_release(rtld_bind_lock, &lockstate); 3550 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3551 return NULL; 3552 } 3553 3554 void * 3555 dlsym(void *handle, const char *name) 3556 { 3557 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3558 SYMLOOK_DLSYM); 3559 } 3560 3561 dlfunc_t 3562 dlfunc(void *handle, const char *name) 3563 { 3564 union { 3565 void *d; 3566 dlfunc_t f; 3567 } rv; 3568 3569 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3570 SYMLOOK_DLSYM); 3571 return (rv.f); 3572 } 3573 3574 void * 3575 dlvsym(void *handle, const char *name, const char *version) 3576 { 3577 Ver_Entry ventry; 3578 3579 ventry.name = version; 3580 ventry.file = NULL; 3581 ventry.hash = elf_hash(version); 3582 ventry.flags= 0; 3583 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3584 SYMLOOK_DLSYM); 3585 } 3586 3587 int 3588 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3589 { 3590 const Obj_Entry *obj; 3591 RtldLockState lockstate; 3592 3593 rlock_acquire(rtld_bind_lock, &lockstate); 3594 obj = obj_from_addr(addr); 3595 if (obj == NULL) { 3596 _rtld_error("No shared object contains address"); 3597 lock_release(rtld_bind_lock, &lockstate); 3598 return (0); 3599 } 3600 rtld_fill_dl_phdr_info(obj, phdr_info); 3601 lock_release(rtld_bind_lock, &lockstate); 3602 return (1); 3603 } 3604 3605 int 3606 dladdr(const void *addr, Dl_info *info) 3607 { 3608 const Obj_Entry *obj; 3609 const Elf_Sym *def; 3610 void *symbol_addr; 3611 unsigned long symoffset; 3612 RtldLockState lockstate; 3613 3614 rlock_acquire(rtld_bind_lock, &lockstate); 3615 obj = obj_from_addr(addr); 3616 if (obj == NULL) { 3617 _rtld_error("No shared object contains address"); 3618 lock_release(rtld_bind_lock, &lockstate); 3619 return 0; 3620 } 3621 info->dli_fname = obj->path; 3622 info->dli_fbase = obj->mapbase; 3623 info->dli_saddr = (void *)0; 3624 info->dli_sname = NULL; 3625 3626 /* 3627 * Walk the symbol list looking for the symbol whose address is 3628 * closest to the address sent in. 3629 */ 3630 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3631 def = obj->symtab + symoffset; 3632 3633 /* 3634 * For skip the symbol if st_shndx is either SHN_UNDEF or 3635 * SHN_COMMON. 3636 */ 3637 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3638 continue; 3639 3640 /* 3641 * If the symbol is greater than the specified address, or if it 3642 * is further away from addr than the current nearest symbol, 3643 * then reject it. 3644 */ 3645 symbol_addr = obj->relocbase + def->st_value; 3646 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3647 continue; 3648 3649 /* Update our idea of the nearest symbol. */ 3650 info->dli_sname = obj->strtab + def->st_name; 3651 info->dli_saddr = symbol_addr; 3652 3653 /* Exact match? */ 3654 if (info->dli_saddr == addr) 3655 break; 3656 } 3657 lock_release(rtld_bind_lock, &lockstate); 3658 return 1; 3659 } 3660 3661 int 3662 dlinfo(void *handle, int request, void *p) 3663 { 3664 const Obj_Entry *obj; 3665 RtldLockState lockstate; 3666 int error; 3667 3668 rlock_acquire(rtld_bind_lock, &lockstate); 3669 3670 if (handle == NULL || handle == RTLD_SELF) { 3671 void *retaddr; 3672 3673 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3674 if ((obj = obj_from_addr(retaddr)) == NULL) 3675 _rtld_error("Cannot determine caller's shared object"); 3676 } else 3677 obj = dlcheck(handle); 3678 3679 if (obj == NULL) { 3680 lock_release(rtld_bind_lock, &lockstate); 3681 return (-1); 3682 } 3683 3684 error = 0; 3685 switch (request) { 3686 case RTLD_DI_LINKMAP: 3687 *((struct link_map const **)p) = &obj->linkmap; 3688 break; 3689 case RTLD_DI_ORIGIN: 3690 error = rtld_dirname(obj->path, p); 3691 break; 3692 3693 case RTLD_DI_SERINFOSIZE: 3694 case RTLD_DI_SERINFO: 3695 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3696 break; 3697 3698 default: 3699 _rtld_error("Invalid request %d passed to dlinfo()", request); 3700 error = -1; 3701 } 3702 3703 lock_release(rtld_bind_lock, &lockstate); 3704 3705 return (error); 3706 } 3707 3708 static void 3709 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3710 { 3711 3712 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3713 phdr_info->dlpi_name = obj->path; 3714 phdr_info->dlpi_phdr = obj->phdr; 3715 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3716 phdr_info->dlpi_tls_modid = obj->tlsindex; 3717 phdr_info->dlpi_tls_data = obj->tlsinit; 3718 phdr_info->dlpi_adds = obj_loads; 3719 phdr_info->dlpi_subs = obj_loads - obj_count; 3720 } 3721 3722 int 3723 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3724 { 3725 struct dl_phdr_info phdr_info; 3726 Obj_Entry *obj, marker; 3727 RtldLockState bind_lockstate, phdr_lockstate; 3728 int error; 3729 3730 init_marker(&marker); 3731 error = 0; 3732 3733 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3734 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3735 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3736 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3737 rtld_fill_dl_phdr_info(obj, &phdr_info); 3738 hold_object(obj); 3739 lock_release(rtld_bind_lock, &bind_lockstate); 3740 3741 error = callback(&phdr_info, sizeof phdr_info, param); 3742 3743 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3744 unhold_object(obj); 3745 obj = globallist_next(&marker); 3746 TAILQ_REMOVE(&obj_list, &marker, next); 3747 if (error != 0) { 3748 lock_release(rtld_bind_lock, &bind_lockstate); 3749 lock_release(rtld_phdr_lock, &phdr_lockstate); 3750 return (error); 3751 } 3752 } 3753 3754 if (error == 0) { 3755 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3756 lock_release(rtld_bind_lock, &bind_lockstate); 3757 error = callback(&phdr_info, sizeof(phdr_info), param); 3758 } 3759 lock_release(rtld_phdr_lock, &phdr_lockstate); 3760 return (error); 3761 } 3762 3763 static void * 3764 fill_search_info(const char *dir, size_t dirlen, void *param) 3765 { 3766 struct fill_search_info_args *arg; 3767 3768 arg = param; 3769 3770 if (arg->request == RTLD_DI_SERINFOSIZE) { 3771 arg->serinfo->dls_cnt ++; 3772 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3773 } else { 3774 struct dl_serpath *s_entry; 3775 3776 s_entry = arg->serpath; 3777 s_entry->dls_name = arg->strspace; 3778 s_entry->dls_flags = arg->flags; 3779 3780 strncpy(arg->strspace, dir, dirlen); 3781 arg->strspace[dirlen] = '\0'; 3782 3783 arg->strspace += dirlen + 1; 3784 arg->serpath++; 3785 } 3786 3787 return (NULL); 3788 } 3789 3790 static int 3791 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3792 { 3793 struct dl_serinfo _info; 3794 struct fill_search_info_args args; 3795 3796 args.request = RTLD_DI_SERINFOSIZE; 3797 args.serinfo = &_info; 3798 3799 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3800 _info.dls_cnt = 0; 3801 3802 path_enumerate(obj->rpath, fill_search_info, &args); 3803 path_enumerate(ld_library_path, fill_search_info, &args); 3804 path_enumerate(obj->runpath, fill_search_info, &args); 3805 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3806 if (!obj->z_nodeflib) 3807 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3808 3809 3810 if (request == RTLD_DI_SERINFOSIZE) { 3811 info->dls_size = _info.dls_size; 3812 info->dls_cnt = _info.dls_cnt; 3813 return (0); 3814 } 3815 3816 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3817 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3818 return (-1); 3819 } 3820 3821 args.request = RTLD_DI_SERINFO; 3822 args.serinfo = info; 3823 args.serpath = &info->dls_serpath[0]; 3824 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3825 3826 args.flags = LA_SER_RUNPATH; 3827 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3828 return (-1); 3829 3830 args.flags = LA_SER_LIBPATH; 3831 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3832 return (-1); 3833 3834 args.flags = LA_SER_RUNPATH; 3835 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3836 return (-1); 3837 3838 args.flags = LA_SER_CONFIG; 3839 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3840 != NULL) 3841 return (-1); 3842 3843 args.flags = LA_SER_DEFAULT; 3844 if (!obj->z_nodeflib && 3845 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3846 return (-1); 3847 return (0); 3848 } 3849 3850 static int 3851 rtld_dirname(const char *path, char *bname) 3852 { 3853 const char *endp; 3854 3855 /* Empty or NULL string gets treated as "." */ 3856 if (path == NULL || *path == '\0') { 3857 bname[0] = '.'; 3858 bname[1] = '\0'; 3859 return (0); 3860 } 3861 3862 /* Strip trailing slashes */ 3863 endp = path + strlen(path) - 1; 3864 while (endp > path && *endp == '/') 3865 endp--; 3866 3867 /* Find the start of the dir */ 3868 while (endp > path && *endp != '/') 3869 endp--; 3870 3871 /* Either the dir is "/" or there are no slashes */ 3872 if (endp == path) { 3873 bname[0] = *endp == '/' ? '/' : '.'; 3874 bname[1] = '\0'; 3875 return (0); 3876 } else { 3877 do { 3878 endp--; 3879 } while (endp > path && *endp == '/'); 3880 } 3881 3882 if (endp - path + 2 > PATH_MAX) 3883 { 3884 _rtld_error("Filename is too long: %s", path); 3885 return(-1); 3886 } 3887 3888 strncpy(bname, path, endp - path + 1); 3889 bname[endp - path + 1] = '\0'; 3890 return (0); 3891 } 3892 3893 static int 3894 rtld_dirname_abs(const char *path, char *base) 3895 { 3896 char *last; 3897 3898 if (realpath(path, base) == NULL) 3899 return (-1); 3900 dbg("%s -> %s", path, base); 3901 last = strrchr(base, '/'); 3902 if (last == NULL) 3903 return (-1); 3904 if (last != base) 3905 *last = '\0'; 3906 return (0); 3907 } 3908 3909 static void 3910 linkmap_add(Obj_Entry *obj) 3911 { 3912 struct link_map *l = &obj->linkmap; 3913 struct link_map *prev; 3914 3915 obj->linkmap.l_name = obj->path; 3916 obj->linkmap.l_addr = obj->mapbase; 3917 obj->linkmap.l_ld = obj->dynamic; 3918 #ifdef __mips__ 3919 /* GDB needs load offset on MIPS to use the symbols */ 3920 obj->linkmap.l_offs = obj->relocbase; 3921 #endif 3922 3923 if (r_debug.r_map == NULL) { 3924 r_debug.r_map = l; 3925 return; 3926 } 3927 3928 /* 3929 * Scan to the end of the list, but not past the entry for the 3930 * dynamic linker, which we want to keep at the very end. 3931 */ 3932 for (prev = r_debug.r_map; 3933 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3934 prev = prev->l_next) 3935 ; 3936 3937 /* Link in the new entry. */ 3938 l->l_prev = prev; 3939 l->l_next = prev->l_next; 3940 if (l->l_next != NULL) 3941 l->l_next->l_prev = l; 3942 prev->l_next = l; 3943 } 3944 3945 static void 3946 linkmap_delete(Obj_Entry *obj) 3947 { 3948 struct link_map *l = &obj->linkmap; 3949 3950 if (l->l_prev == NULL) { 3951 if ((r_debug.r_map = l->l_next) != NULL) 3952 l->l_next->l_prev = NULL; 3953 return; 3954 } 3955 3956 if ((l->l_prev->l_next = l->l_next) != NULL) 3957 l->l_next->l_prev = l->l_prev; 3958 } 3959 3960 /* 3961 * Function for the debugger to set a breakpoint on to gain control. 3962 * 3963 * The two parameters allow the debugger to easily find and determine 3964 * what the runtime loader is doing and to whom it is doing it. 3965 * 3966 * When the loadhook trap is hit (r_debug_state, set at program 3967 * initialization), the arguments can be found on the stack: 3968 * 3969 * +8 struct link_map *m 3970 * +4 struct r_debug *rd 3971 * +0 RetAddr 3972 */ 3973 void 3974 r_debug_state(struct r_debug* rd, struct link_map *m) 3975 { 3976 /* 3977 * The following is a hack to force the compiler to emit calls to 3978 * this function, even when optimizing. If the function is empty, 3979 * the compiler is not obliged to emit any code for calls to it, 3980 * even when marked __noinline. However, gdb depends on those 3981 * calls being made. 3982 */ 3983 __compiler_membar(); 3984 } 3985 3986 /* 3987 * A function called after init routines have completed. This can be used to 3988 * break before a program's entry routine is called, and can be used when 3989 * main is not available in the symbol table. 3990 */ 3991 void 3992 _r_debug_postinit(struct link_map *m) 3993 { 3994 3995 /* See r_debug_state(). */ 3996 __compiler_membar(); 3997 } 3998 3999 static void 4000 release_object(Obj_Entry *obj) 4001 { 4002 4003 if (obj->holdcount > 0) { 4004 obj->unholdfree = true; 4005 return; 4006 } 4007 munmap(obj->mapbase, obj->mapsize); 4008 linkmap_delete(obj); 4009 obj_free(obj); 4010 } 4011 4012 /* 4013 * Get address of the pointer variable in the main program. 4014 * Prefer non-weak symbol over the weak one. 4015 */ 4016 static const void ** 4017 get_program_var_addr(const char *name, RtldLockState *lockstate) 4018 { 4019 SymLook req; 4020 DoneList donelist; 4021 4022 symlook_init(&req, name); 4023 req.lockstate = lockstate; 4024 donelist_init(&donelist); 4025 if (symlook_global(&req, &donelist) != 0) 4026 return (NULL); 4027 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4028 return ((const void **)make_function_pointer(req.sym_out, 4029 req.defobj_out)); 4030 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4031 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4032 else 4033 return ((const void **)(req.defobj_out->relocbase + 4034 req.sym_out->st_value)); 4035 } 4036 4037 /* 4038 * Set a pointer variable in the main program to the given value. This 4039 * is used to set key variables such as "environ" before any of the 4040 * init functions are called. 4041 */ 4042 static void 4043 set_program_var(const char *name, const void *value) 4044 { 4045 const void **addr; 4046 4047 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4048 dbg("\"%s\": *%p <-- %p", name, addr, value); 4049 *addr = value; 4050 } 4051 } 4052 4053 /* 4054 * Search the global objects, including dependencies and main object, 4055 * for the given symbol. 4056 */ 4057 static int 4058 symlook_global(SymLook *req, DoneList *donelist) 4059 { 4060 SymLook req1; 4061 const Objlist_Entry *elm; 4062 int res; 4063 4064 symlook_init_from_req(&req1, req); 4065 4066 /* Search all objects loaded at program start up. */ 4067 if (req->defobj_out == NULL || 4068 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4069 res = symlook_list(&req1, &list_main, donelist); 4070 if (res == 0 && (req->defobj_out == NULL || 4071 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4072 req->sym_out = req1.sym_out; 4073 req->defobj_out = req1.defobj_out; 4074 assert(req->defobj_out != NULL); 4075 } 4076 } 4077 4078 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4079 STAILQ_FOREACH(elm, &list_global, link) { 4080 if (req->defobj_out != NULL && 4081 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4082 break; 4083 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4084 if (res == 0 && (req->defobj_out == NULL || 4085 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4086 req->sym_out = req1.sym_out; 4087 req->defobj_out = req1.defobj_out; 4088 assert(req->defobj_out != NULL); 4089 } 4090 } 4091 4092 return (req->sym_out != NULL ? 0 : ESRCH); 4093 } 4094 4095 /* 4096 * Given a symbol name in a referencing object, find the corresponding 4097 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4098 * no definition was found. Returns a pointer to the Obj_Entry of the 4099 * defining object via the reference parameter DEFOBJ_OUT. 4100 */ 4101 static int 4102 symlook_default(SymLook *req, const Obj_Entry *refobj) 4103 { 4104 DoneList donelist; 4105 const Objlist_Entry *elm; 4106 SymLook req1; 4107 int res; 4108 4109 donelist_init(&donelist); 4110 symlook_init_from_req(&req1, req); 4111 4112 /* 4113 * Look first in the referencing object if linked symbolically, 4114 * and similarly handle protected symbols. 4115 */ 4116 res = symlook_obj(&req1, refobj); 4117 if (res == 0 && (refobj->symbolic || 4118 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4119 req->sym_out = req1.sym_out; 4120 req->defobj_out = req1.defobj_out; 4121 assert(req->defobj_out != NULL); 4122 } 4123 if (refobj->symbolic || req->defobj_out != NULL) 4124 donelist_check(&donelist, refobj); 4125 4126 symlook_global(req, &donelist); 4127 4128 /* Search all dlopened DAGs containing the referencing object. */ 4129 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4130 if (req->sym_out != NULL && 4131 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4132 break; 4133 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4134 if (res == 0 && (req->sym_out == NULL || 4135 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4136 req->sym_out = req1.sym_out; 4137 req->defobj_out = req1.defobj_out; 4138 assert(req->defobj_out != NULL); 4139 } 4140 } 4141 4142 /* 4143 * Search the dynamic linker itself, and possibly resolve the 4144 * symbol from there. This is how the application links to 4145 * dynamic linker services such as dlopen. 4146 */ 4147 if (req->sym_out == NULL || 4148 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4149 res = symlook_obj(&req1, &obj_rtld); 4150 if (res == 0) { 4151 req->sym_out = req1.sym_out; 4152 req->defobj_out = req1.defobj_out; 4153 assert(req->defobj_out != NULL); 4154 } 4155 } 4156 4157 return (req->sym_out != NULL ? 0 : ESRCH); 4158 } 4159 4160 static int 4161 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4162 { 4163 const Elf_Sym *def; 4164 const Obj_Entry *defobj; 4165 const Objlist_Entry *elm; 4166 SymLook req1; 4167 int res; 4168 4169 def = NULL; 4170 defobj = NULL; 4171 STAILQ_FOREACH(elm, objlist, link) { 4172 if (donelist_check(dlp, elm->obj)) 4173 continue; 4174 symlook_init_from_req(&req1, req); 4175 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4176 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4177 def = req1.sym_out; 4178 defobj = req1.defobj_out; 4179 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4180 break; 4181 } 4182 } 4183 } 4184 if (def != NULL) { 4185 req->sym_out = def; 4186 req->defobj_out = defobj; 4187 return (0); 4188 } 4189 return (ESRCH); 4190 } 4191 4192 /* 4193 * Search the chain of DAGS cointed to by the given Needed_Entry 4194 * for a symbol of the given name. Each DAG is scanned completely 4195 * before advancing to the next one. Returns a pointer to the symbol, 4196 * or NULL if no definition was found. 4197 */ 4198 static int 4199 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4200 { 4201 const Elf_Sym *def; 4202 const Needed_Entry *n; 4203 const Obj_Entry *defobj; 4204 SymLook req1; 4205 int res; 4206 4207 def = NULL; 4208 defobj = NULL; 4209 symlook_init_from_req(&req1, req); 4210 for (n = needed; n != NULL; n = n->next) { 4211 if (n->obj == NULL || 4212 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4213 continue; 4214 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4215 def = req1.sym_out; 4216 defobj = req1.defobj_out; 4217 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4218 break; 4219 } 4220 } 4221 if (def != NULL) { 4222 req->sym_out = def; 4223 req->defobj_out = defobj; 4224 return (0); 4225 } 4226 return (ESRCH); 4227 } 4228 4229 /* 4230 * Search the symbol table of a single shared object for a symbol of 4231 * the given name and version, if requested. Returns a pointer to the 4232 * symbol, or NULL if no definition was found. If the object is 4233 * filter, return filtered symbol from filtee. 4234 * 4235 * The symbol's hash value is passed in for efficiency reasons; that 4236 * eliminates many recomputations of the hash value. 4237 */ 4238 int 4239 symlook_obj(SymLook *req, const Obj_Entry *obj) 4240 { 4241 DoneList donelist; 4242 SymLook req1; 4243 int flags, res, mres; 4244 4245 /* 4246 * If there is at least one valid hash at this point, we prefer to 4247 * use the faster GNU version if available. 4248 */ 4249 if (obj->valid_hash_gnu) 4250 mres = symlook_obj1_gnu(req, obj); 4251 else if (obj->valid_hash_sysv) 4252 mres = symlook_obj1_sysv(req, obj); 4253 else 4254 return (EINVAL); 4255 4256 if (mres == 0) { 4257 if (obj->needed_filtees != NULL) { 4258 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4259 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4260 donelist_init(&donelist); 4261 symlook_init_from_req(&req1, req); 4262 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4263 if (res == 0) { 4264 req->sym_out = req1.sym_out; 4265 req->defobj_out = req1.defobj_out; 4266 } 4267 return (res); 4268 } 4269 if (obj->needed_aux_filtees != NULL) { 4270 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4271 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4272 donelist_init(&donelist); 4273 symlook_init_from_req(&req1, req); 4274 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4275 if (res == 0) { 4276 req->sym_out = req1.sym_out; 4277 req->defobj_out = req1.defobj_out; 4278 return (res); 4279 } 4280 } 4281 } 4282 return (mres); 4283 } 4284 4285 /* Symbol match routine common to both hash functions */ 4286 static bool 4287 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4288 const unsigned long symnum) 4289 { 4290 Elf_Versym verndx; 4291 const Elf_Sym *symp; 4292 const char *strp; 4293 4294 symp = obj->symtab + symnum; 4295 strp = obj->strtab + symp->st_name; 4296 4297 switch (ELF_ST_TYPE(symp->st_info)) { 4298 case STT_FUNC: 4299 case STT_NOTYPE: 4300 case STT_OBJECT: 4301 case STT_COMMON: 4302 case STT_GNU_IFUNC: 4303 if (symp->st_value == 0) 4304 return (false); 4305 /* fallthrough */ 4306 case STT_TLS: 4307 if (symp->st_shndx != SHN_UNDEF) 4308 break; 4309 #ifndef __mips__ 4310 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4311 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4312 break; 4313 /* fallthrough */ 4314 #endif 4315 default: 4316 return (false); 4317 } 4318 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4319 return (false); 4320 4321 if (req->ventry == NULL) { 4322 if (obj->versyms != NULL) { 4323 verndx = VER_NDX(obj->versyms[symnum]); 4324 if (verndx > obj->vernum) { 4325 _rtld_error( 4326 "%s: symbol %s references wrong version %d", 4327 obj->path, obj->strtab + symnum, verndx); 4328 return (false); 4329 } 4330 /* 4331 * If we are not called from dlsym (i.e. this 4332 * is a normal relocation from unversioned 4333 * binary), accept the symbol immediately if 4334 * it happens to have first version after this 4335 * shared object became versioned. Otherwise, 4336 * if symbol is versioned and not hidden, 4337 * remember it. If it is the only symbol with 4338 * this name exported by the shared object, it 4339 * will be returned as a match by the calling 4340 * function. If symbol is global (verndx < 2) 4341 * accept it unconditionally. 4342 */ 4343 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4344 verndx == VER_NDX_GIVEN) { 4345 result->sym_out = symp; 4346 return (true); 4347 } 4348 else if (verndx >= VER_NDX_GIVEN) { 4349 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4350 == 0) { 4351 if (result->vsymp == NULL) 4352 result->vsymp = symp; 4353 result->vcount++; 4354 } 4355 return (false); 4356 } 4357 } 4358 result->sym_out = symp; 4359 return (true); 4360 } 4361 if (obj->versyms == NULL) { 4362 if (object_match_name(obj, req->ventry->name)) { 4363 _rtld_error("%s: object %s should provide version %s " 4364 "for symbol %s", obj_rtld.path, obj->path, 4365 req->ventry->name, obj->strtab + symnum); 4366 return (false); 4367 } 4368 } else { 4369 verndx = VER_NDX(obj->versyms[symnum]); 4370 if (verndx > obj->vernum) { 4371 _rtld_error("%s: symbol %s references wrong version %d", 4372 obj->path, obj->strtab + symnum, verndx); 4373 return (false); 4374 } 4375 if (obj->vertab[verndx].hash != req->ventry->hash || 4376 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4377 /* 4378 * Version does not match. Look if this is a 4379 * global symbol and if it is not hidden. If 4380 * global symbol (verndx < 2) is available, 4381 * use it. Do not return symbol if we are 4382 * called by dlvsym, because dlvsym looks for 4383 * a specific version and default one is not 4384 * what dlvsym wants. 4385 */ 4386 if ((req->flags & SYMLOOK_DLSYM) || 4387 (verndx >= VER_NDX_GIVEN) || 4388 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4389 return (false); 4390 } 4391 } 4392 result->sym_out = symp; 4393 return (true); 4394 } 4395 4396 /* 4397 * Search for symbol using SysV hash function. 4398 * obj->buckets is known not to be NULL at this point; the test for this was 4399 * performed with the obj->valid_hash_sysv assignment. 4400 */ 4401 static int 4402 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4403 { 4404 unsigned long symnum; 4405 Sym_Match_Result matchres; 4406 4407 matchres.sym_out = NULL; 4408 matchres.vsymp = NULL; 4409 matchres.vcount = 0; 4410 4411 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4412 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4413 if (symnum >= obj->nchains) 4414 return (ESRCH); /* Bad object */ 4415 4416 if (matched_symbol(req, obj, &matchres, symnum)) { 4417 req->sym_out = matchres.sym_out; 4418 req->defobj_out = obj; 4419 return (0); 4420 } 4421 } 4422 if (matchres.vcount == 1) { 4423 req->sym_out = matchres.vsymp; 4424 req->defobj_out = obj; 4425 return (0); 4426 } 4427 return (ESRCH); 4428 } 4429 4430 /* Search for symbol using GNU hash function */ 4431 static int 4432 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4433 { 4434 Elf_Addr bloom_word; 4435 const Elf32_Word *hashval; 4436 Elf32_Word bucket; 4437 Sym_Match_Result matchres; 4438 unsigned int h1, h2; 4439 unsigned long symnum; 4440 4441 matchres.sym_out = NULL; 4442 matchres.vsymp = NULL; 4443 matchres.vcount = 0; 4444 4445 /* Pick right bitmask word from Bloom filter array */ 4446 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4447 obj->maskwords_bm_gnu]; 4448 4449 /* Calculate modulus word size of gnu hash and its derivative */ 4450 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4451 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4452 4453 /* Filter out the "definitely not in set" queries */ 4454 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4455 return (ESRCH); 4456 4457 /* Locate hash chain and corresponding value element*/ 4458 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4459 if (bucket == 0) 4460 return (ESRCH); 4461 hashval = &obj->chain_zero_gnu[bucket]; 4462 do { 4463 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4464 symnum = hashval - obj->chain_zero_gnu; 4465 if (matched_symbol(req, obj, &matchres, symnum)) { 4466 req->sym_out = matchres.sym_out; 4467 req->defobj_out = obj; 4468 return (0); 4469 } 4470 } 4471 } while ((*hashval++ & 1) == 0); 4472 if (matchres.vcount == 1) { 4473 req->sym_out = matchres.vsymp; 4474 req->defobj_out = obj; 4475 return (0); 4476 } 4477 return (ESRCH); 4478 } 4479 4480 static void 4481 trace_loaded_objects(Obj_Entry *obj) 4482 { 4483 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4484 int c; 4485 4486 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4487 main_local = ""; 4488 4489 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4490 fmt1 = "\t%o => %p (%x)\n"; 4491 4492 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4493 fmt2 = "\t%o (%x)\n"; 4494 4495 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4496 4497 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4498 Needed_Entry *needed; 4499 char *name, *path; 4500 bool is_lib; 4501 4502 if (obj->marker) 4503 continue; 4504 if (list_containers && obj->needed != NULL) 4505 rtld_printf("%s:\n", obj->path); 4506 for (needed = obj->needed; needed; needed = needed->next) { 4507 if (needed->obj != NULL) { 4508 if (needed->obj->traced && !list_containers) 4509 continue; 4510 needed->obj->traced = true; 4511 path = needed->obj->path; 4512 } else 4513 path = "not found"; 4514 4515 name = (char *)obj->strtab + needed->name; 4516 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4517 4518 fmt = is_lib ? fmt1 : fmt2; 4519 while ((c = *fmt++) != '\0') { 4520 switch (c) { 4521 default: 4522 rtld_putchar(c); 4523 continue; 4524 case '\\': 4525 switch (c = *fmt) { 4526 case '\0': 4527 continue; 4528 case 'n': 4529 rtld_putchar('\n'); 4530 break; 4531 case 't': 4532 rtld_putchar('\t'); 4533 break; 4534 } 4535 break; 4536 case '%': 4537 switch (c = *fmt) { 4538 case '\0': 4539 continue; 4540 case '%': 4541 default: 4542 rtld_putchar(c); 4543 break; 4544 case 'A': 4545 rtld_putstr(main_local); 4546 break; 4547 case 'a': 4548 rtld_putstr(obj_main->path); 4549 break; 4550 case 'o': 4551 rtld_putstr(name); 4552 break; 4553 #if 0 4554 case 'm': 4555 rtld_printf("%d", sodp->sod_major); 4556 break; 4557 case 'n': 4558 rtld_printf("%d", sodp->sod_minor); 4559 break; 4560 #endif 4561 case 'p': 4562 rtld_putstr(path); 4563 break; 4564 case 'x': 4565 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4566 0); 4567 break; 4568 } 4569 break; 4570 } 4571 ++fmt; 4572 } 4573 } 4574 } 4575 } 4576 4577 /* 4578 * Unload a dlopened object and its dependencies from memory and from 4579 * our data structures. It is assumed that the DAG rooted in the 4580 * object has already been unreferenced, and that the object has a 4581 * reference count of 0. 4582 */ 4583 static void 4584 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4585 { 4586 Obj_Entry marker, *obj, *next; 4587 4588 assert(root->refcount == 0); 4589 4590 /* 4591 * Pass over the DAG removing unreferenced objects from 4592 * appropriate lists. 4593 */ 4594 unlink_object(root); 4595 4596 /* Unmap all objects that are no longer referenced. */ 4597 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4598 next = TAILQ_NEXT(obj, next); 4599 if (obj->marker || obj->refcount != 0) 4600 continue; 4601 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4602 obj->mapsize, 0, obj->path); 4603 dbg("unloading \"%s\"", obj->path); 4604 /* 4605 * Unlink the object now to prevent new references from 4606 * being acquired while the bind lock is dropped in 4607 * recursive dlclose() invocations. 4608 */ 4609 TAILQ_REMOVE(&obj_list, obj, next); 4610 obj_count--; 4611 4612 if (obj->filtees_loaded) { 4613 if (next != NULL) { 4614 init_marker(&marker); 4615 TAILQ_INSERT_BEFORE(next, &marker, next); 4616 unload_filtees(obj, lockstate); 4617 next = TAILQ_NEXT(&marker, next); 4618 TAILQ_REMOVE(&obj_list, &marker, next); 4619 } else 4620 unload_filtees(obj, lockstate); 4621 } 4622 release_object(obj); 4623 } 4624 } 4625 4626 static void 4627 unlink_object(Obj_Entry *root) 4628 { 4629 Objlist_Entry *elm; 4630 4631 if (root->refcount == 0) { 4632 /* Remove the object from the RTLD_GLOBAL list. */ 4633 objlist_remove(&list_global, root); 4634 4635 /* Remove the object from all objects' DAG lists. */ 4636 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4637 objlist_remove(&elm->obj->dldags, root); 4638 if (elm->obj != root) 4639 unlink_object(elm->obj); 4640 } 4641 } 4642 } 4643 4644 static void 4645 ref_dag(Obj_Entry *root) 4646 { 4647 Objlist_Entry *elm; 4648 4649 assert(root->dag_inited); 4650 STAILQ_FOREACH(elm, &root->dagmembers, link) 4651 elm->obj->refcount++; 4652 } 4653 4654 static void 4655 unref_dag(Obj_Entry *root) 4656 { 4657 Objlist_Entry *elm; 4658 4659 assert(root->dag_inited); 4660 STAILQ_FOREACH(elm, &root->dagmembers, link) 4661 elm->obj->refcount--; 4662 } 4663 4664 /* 4665 * Common code for MD __tls_get_addr(). 4666 */ 4667 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4668 static void * 4669 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4670 { 4671 Elf_Addr *newdtv, *dtv; 4672 RtldLockState lockstate; 4673 int to_copy; 4674 4675 dtv = *dtvp; 4676 /* Check dtv generation in case new modules have arrived */ 4677 if (dtv[0] != tls_dtv_generation) { 4678 wlock_acquire(rtld_bind_lock, &lockstate); 4679 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4680 to_copy = dtv[1]; 4681 if (to_copy > tls_max_index) 4682 to_copy = tls_max_index; 4683 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4684 newdtv[0] = tls_dtv_generation; 4685 newdtv[1] = tls_max_index; 4686 free(dtv); 4687 lock_release(rtld_bind_lock, &lockstate); 4688 dtv = *dtvp = newdtv; 4689 } 4690 4691 /* Dynamically allocate module TLS if necessary */ 4692 if (dtv[index + 1] == 0) { 4693 /* Signal safe, wlock will block out signals. */ 4694 wlock_acquire(rtld_bind_lock, &lockstate); 4695 if (!dtv[index + 1]) 4696 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4697 lock_release(rtld_bind_lock, &lockstate); 4698 } 4699 return ((void *)(dtv[index + 1] + offset)); 4700 } 4701 4702 void * 4703 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4704 { 4705 Elf_Addr *dtv; 4706 4707 dtv = *dtvp; 4708 /* Check dtv generation in case new modules have arrived */ 4709 if (__predict_true(dtv[0] == tls_dtv_generation && 4710 dtv[index + 1] != 0)) 4711 return ((void *)(dtv[index + 1] + offset)); 4712 return (tls_get_addr_slow(dtvp, index, offset)); 4713 } 4714 4715 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4716 defined(__powerpc__) || defined(__riscv) 4717 4718 /* 4719 * Allocate Static TLS using the Variant I method. 4720 */ 4721 void * 4722 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4723 { 4724 Obj_Entry *obj; 4725 char *tcb; 4726 Elf_Addr **tls; 4727 Elf_Addr *dtv; 4728 Elf_Addr addr; 4729 int i; 4730 4731 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4732 return (oldtcb); 4733 4734 assert(tcbsize >= TLS_TCB_SIZE); 4735 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4736 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4737 4738 if (oldtcb != NULL) { 4739 memcpy(tls, oldtcb, tls_static_space); 4740 free(oldtcb); 4741 4742 /* Adjust the DTV. */ 4743 dtv = tls[0]; 4744 for (i = 0; i < dtv[1]; i++) { 4745 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4746 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4747 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4748 } 4749 } 4750 } else { 4751 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4752 tls[0] = dtv; 4753 dtv[0] = tls_dtv_generation; 4754 dtv[1] = tls_max_index; 4755 4756 for (obj = globallist_curr(objs); obj != NULL; 4757 obj = globallist_next(obj)) { 4758 if (obj->tlsoffset > 0) { 4759 addr = (Elf_Addr)tls + obj->tlsoffset; 4760 if (obj->tlsinitsize > 0) 4761 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4762 if (obj->tlssize > obj->tlsinitsize) 4763 memset((void*) (addr + obj->tlsinitsize), 0, 4764 obj->tlssize - obj->tlsinitsize); 4765 dtv[obj->tlsindex + 1] = addr; 4766 } 4767 } 4768 } 4769 4770 return (tcb); 4771 } 4772 4773 void 4774 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4775 { 4776 Elf_Addr *dtv; 4777 Elf_Addr tlsstart, tlsend; 4778 int dtvsize, i; 4779 4780 assert(tcbsize >= TLS_TCB_SIZE); 4781 4782 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4783 tlsend = tlsstart + tls_static_space; 4784 4785 dtv = *(Elf_Addr **)tlsstart; 4786 dtvsize = dtv[1]; 4787 for (i = 0; i < dtvsize; i++) { 4788 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4789 free((void*)dtv[i+2]); 4790 } 4791 } 4792 free(dtv); 4793 free(tcb); 4794 } 4795 4796 #endif 4797 4798 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4799 4800 /* 4801 * Allocate Static TLS using the Variant II method. 4802 */ 4803 void * 4804 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4805 { 4806 Obj_Entry *obj; 4807 size_t size, ralign; 4808 char *tls; 4809 Elf_Addr *dtv, *olddtv; 4810 Elf_Addr segbase, oldsegbase, addr; 4811 int i; 4812 4813 ralign = tcbalign; 4814 if (tls_static_max_align > ralign) 4815 ralign = tls_static_max_align; 4816 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4817 4818 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4819 tls = malloc_aligned(size, ralign); 4820 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4821 4822 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4823 ((Elf_Addr*)segbase)[0] = segbase; 4824 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4825 4826 dtv[0] = tls_dtv_generation; 4827 dtv[1] = tls_max_index; 4828 4829 if (oldtls) { 4830 /* 4831 * Copy the static TLS block over whole. 4832 */ 4833 oldsegbase = (Elf_Addr) oldtls; 4834 memcpy((void *)(segbase - tls_static_space), 4835 (const void *)(oldsegbase - tls_static_space), 4836 tls_static_space); 4837 4838 /* 4839 * If any dynamic TLS blocks have been created tls_get_addr(), 4840 * move them over. 4841 */ 4842 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4843 for (i = 0; i < olddtv[1]; i++) { 4844 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4845 dtv[i+2] = olddtv[i+2]; 4846 olddtv[i+2] = 0; 4847 } 4848 } 4849 4850 /* 4851 * We assume that this block was the one we created with 4852 * allocate_initial_tls(). 4853 */ 4854 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4855 } else { 4856 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4857 if (obj->marker || obj->tlsoffset == 0) 4858 continue; 4859 addr = segbase - obj->tlsoffset; 4860 memset((void*) (addr + obj->tlsinitsize), 4861 0, obj->tlssize - obj->tlsinitsize); 4862 if (obj->tlsinit) 4863 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4864 dtv[obj->tlsindex + 1] = addr; 4865 } 4866 } 4867 4868 return (void*) segbase; 4869 } 4870 4871 void 4872 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4873 { 4874 Elf_Addr* dtv; 4875 size_t size, ralign; 4876 int dtvsize, i; 4877 Elf_Addr tlsstart, tlsend; 4878 4879 /* 4880 * Figure out the size of the initial TLS block so that we can 4881 * find stuff which ___tls_get_addr() allocated dynamically. 4882 */ 4883 ralign = tcbalign; 4884 if (tls_static_max_align > ralign) 4885 ralign = tls_static_max_align; 4886 size = round(tls_static_space, ralign); 4887 4888 dtv = ((Elf_Addr**)tls)[1]; 4889 dtvsize = dtv[1]; 4890 tlsend = (Elf_Addr) tls; 4891 tlsstart = tlsend - size; 4892 for (i = 0; i < dtvsize; i++) { 4893 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4894 free_aligned((void *)dtv[i + 2]); 4895 } 4896 } 4897 4898 free_aligned((void *)tlsstart); 4899 free((void*) dtv); 4900 } 4901 4902 #endif 4903 4904 /* 4905 * Allocate TLS block for module with given index. 4906 */ 4907 void * 4908 allocate_module_tls(int index) 4909 { 4910 Obj_Entry* obj; 4911 char* p; 4912 4913 TAILQ_FOREACH(obj, &obj_list, next) { 4914 if (obj->marker) 4915 continue; 4916 if (obj->tlsindex == index) 4917 break; 4918 } 4919 if (!obj) { 4920 _rtld_error("Can't find module with TLS index %d", index); 4921 rtld_die(); 4922 } 4923 4924 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4925 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4926 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4927 4928 return p; 4929 } 4930 4931 bool 4932 allocate_tls_offset(Obj_Entry *obj) 4933 { 4934 size_t off; 4935 4936 if (obj->tls_done) 4937 return true; 4938 4939 if (obj->tlssize == 0) { 4940 obj->tls_done = true; 4941 return true; 4942 } 4943 4944 if (tls_last_offset == 0) 4945 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4946 else 4947 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4948 obj->tlssize, obj->tlsalign); 4949 4950 /* 4951 * If we have already fixed the size of the static TLS block, we 4952 * must stay within that size. When allocating the static TLS, we 4953 * leave a small amount of space spare to be used for dynamically 4954 * loading modules which use static TLS. 4955 */ 4956 if (tls_static_space != 0) { 4957 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4958 return false; 4959 } else if (obj->tlsalign > tls_static_max_align) { 4960 tls_static_max_align = obj->tlsalign; 4961 } 4962 4963 tls_last_offset = obj->tlsoffset = off; 4964 tls_last_size = obj->tlssize; 4965 obj->tls_done = true; 4966 4967 return true; 4968 } 4969 4970 void 4971 free_tls_offset(Obj_Entry *obj) 4972 { 4973 4974 /* 4975 * If we were the last thing to allocate out of the static TLS 4976 * block, we give our space back to the 'allocator'. This is a 4977 * simplistic workaround to allow libGL.so.1 to be loaded and 4978 * unloaded multiple times. 4979 */ 4980 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4981 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4982 tls_last_offset -= obj->tlssize; 4983 tls_last_size = 0; 4984 } 4985 } 4986 4987 void * 4988 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4989 { 4990 void *ret; 4991 RtldLockState lockstate; 4992 4993 wlock_acquire(rtld_bind_lock, &lockstate); 4994 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4995 tcbsize, tcbalign); 4996 lock_release(rtld_bind_lock, &lockstate); 4997 return (ret); 4998 } 4999 5000 void 5001 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5002 { 5003 RtldLockState lockstate; 5004 5005 wlock_acquire(rtld_bind_lock, &lockstate); 5006 free_tls(tcb, tcbsize, tcbalign); 5007 lock_release(rtld_bind_lock, &lockstate); 5008 } 5009 5010 static void 5011 object_add_name(Obj_Entry *obj, const char *name) 5012 { 5013 Name_Entry *entry; 5014 size_t len; 5015 5016 len = strlen(name); 5017 entry = malloc(sizeof(Name_Entry) + len); 5018 5019 if (entry != NULL) { 5020 strcpy(entry->name, name); 5021 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5022 } 5023 } 5024 5025 static int 5026 object_match_name(const Obj_Entry *obj, const char *name) 5027 { 5028 Name_Entry *entry; 5029 5030 STAILQ_FOREACH(entry, &obj->names, link) { 5031 if (strcmp(name, entry->name) == 0) 5032 return (1); 5033 } 5034 return (0); 5035 } 5036 5037 static Obj_Entry * 5038 locate_dependency(const Obj_Entry *obj, const char *name) 5039 { 5040 const Objlist_Entry *entry; 5041 const Needed_Entry *needed; 5042 5043 STAILQ_FOREACH(entry, &list_main, link) { 5044 if (object_match_name(entry->obj, name)) 5045 return entry->obj; 5046 } 5047 5048 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5049 if (strcmp(obj->strtab + needed->name, name) == 0 || 5050 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5051 /* 5052 * If there is DT_NEEDED for the name we are looking for, 5053 * we are all set. Note that object might not be found if 5054 * dependency was not loaded yet, so the function can 5055 * return NULL here. This is expected and handled 5056 * properly by the caller. 5057 */ 5058 return (needed->obj); 5059 } 5060 } 5061 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5062 obj->path, name); 5063 rtld_die(); 5064 } 5065 5066 static int 5067 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5068 const Elf_Vernaux *vna) 5069 { 5070 const Elf_Verdef *vd; 5071 const char *vername; 5072 5073 vername = refobj->strtab + vna->vna_name; 5074 vd = depobj->verdef; 5075 if (vd == NULL) { 5076 _rtld_error("%s: version %s required by %s not defined", 5077 depobj->path, vername, refobj->path); 5078 return (-1); 5079 } 5080 for (;;) { 5081 if (vd->vd_version != VER_DEF_CURRENT) { 5082 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5083 depobj->path, vd->vd_version); 5084 return (-1); 5085 } 5086 if (vna->vna_hash == vd->vd_hash) { 5087 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5088 ((char *)vd + vd->vd_aux); 5089 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5090 return (0); 5091 } 5092 if (vd->vd_next == 0) 5093 break; 5094 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5095 } 5096 if (vna->vna_flags & VER_FLG_WEAK) 5097 return (0); 5098 _rtld_error("%s: version %s required by %s not found", 5099 depobj->path, vername, refobj->path); 5100 return (-1); 5101 } 5102 5103 static int 5104 rtld_verify_object_versions(Obj_Entry *obj) 5105 { 5106 const Elf_Verneed *vn; 5107 const Elf_Verdef *vd; 5108 const Elf_Verdaux *vda; 5109 const Elf_Vernaux *vna; 5110 const Obj_Entry *depobj; 5111 int maxvernum, vernum; 5112 5113 if (obj->ver_checked) 5114 return (0); 5115 obj->ver_checked = true; 5116 5117 maxvernum = 0; 5118 /* 5119 * Walk over defined and required version records and figure out 5120 * max index used by any of them. Do very basic sanity checking 5121 * while there. 5122 */ 5123 vn = obj->verneed; 5124 while (vn != NULL) { 5125 if (vn->vn_version != VER_NEED_CURRENT) { 5126 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5127 obj->path, vn->vn_version); 5128 return (-1); 5129 } 5130 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5131 for (;;) { 5132 vernum = VER_NEED_IDX(vna->vna_other); 5133 if (vernum > maxvernum) 5134 maxvernum = vernum; 5135 if (vna->vna_next == 0) 5136 break; 5137 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5138 } 5139 if (vn->vn_next == 0) 5140 break; 5141 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5142 } 5143 5144 vd = obj->verdef; 5145 while (vd != NULL) { 5146 if (vd->vd_version != VER_DEF_CURRENT) { 5147 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5148 obj->path, vd->vd_version); 5149 return (-1); 5150 } 5151 vernum = VER_DEF_IDX(vd->vd_ndx); 5152 if (vernum > maxvernum) 5153 maxvernum = vernum; 5154 if (vd->vd_next == 0) 5155 break; 5156 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5157 } 5158 5159 if (maxvernum == 0) 5160 return (0); 5161 5162 /* 5163 * Store version information in array indexable by version index. 5164 * Verify that object version requirements are satisfied along the 5165 * way. 5166 */ 5167 obj->vernum = maxvernum + 1; 5168 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5169 5170 vd = obj->verdef; 5171 while (vd != NULL) { 5172 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5173 vernum = VER_DEF_IDX(vd->vd_ndx); 5174 assert(vernum <= maxvernum); 5175 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5176 obj->vertab[vernum].hash = vd->vd_hash; 5177 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5178 obj->vertab[vernum].file = NULL; 5179 obj->vertab[vernum].flags = 0; 5180 } 5181 if (vd->vd_next == 0) 5182 break; 5183 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5184 } 5185 5186 vn = obj->verneed; 5187 while (vn != NULL) { 5188 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5189 if (depobj == NULL) 5190 return (-1); 5191 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5192 for (;;) { 5193 if (check_object_provided_version(obj, depobj, vna)) 5194 return (-1); 5195 vernum = VER_NEED_IDX(vna->vna_other); 5196 assert(vernum <= maxvernum); 5197 obj->vertab[vernum].hash = vna->vna_hash; 5198 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5199 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5200 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5201 VER_INFO_HIDDEN : 0; 5202 if (vna->vna_next == 0) 5203 break; 5204 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5205 } 5206 if (vn->vn_next == 0) 5207 break; 5208 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5209 } 5210 return 0; 5211 } 5212 5213 static int 5214 rtld_verify_versions(const Objlist *objlist) 5215 { 5216 Objlist_Entry *entry; 5217 int rc; 5218 5219 rc = 0; 5220 STAILQ_FOREACH(entry, objlist, link) { 5221 /* 5222 * Skip dummy objects or objects that have their version requirements 5223 * already checked. 5224 */ 5225 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5226 continue; 5227 if (rtld_verify_object_versions(entry->obj) == -1) { 5228 rc = -1; 5229 if (ld_tracing == NULL) 5230 break; 5231 } 5232 } 5233 if (rc == 0 || ld_tracing != NULL) 5234 rc = rtld_verify_object_versions(&obj_rtld); 5235 return rc; 5236 } 5237 5238 const Ver_Entry * 5239 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5240 { 5241 Elf_Versym vernum; 5242 5243 if (obj->vertab) { 5244 vernum = VER_NDX(obj->versyms[symnum]); 5245 if (vernum >= obj->vernum) { 5246 _rtld_error("%s: symbol %s has wrong verneed value %d", 5247 obj->path, obj->strtab + symnum, vernum); 5248 } else if (obj->vertab[vernum].hash != 0) { 5249 return &obj->vertab[vernum]; 5250 } 5251 } 5252 return NULL; 5253 } 5254 5255 int 5256 _rtld_get_stack_prot(void) 5257 { 5258 5259 return (stack_prot); 5260 } 5261 5262 int 5263 _rtld_is_dlopened(void *arg) 5264 { 5265 Obj_Entry *obj; 5266 RtldLockState lockstate; 5267 int res; 5268 5269 rlock_acquire(rtld_bind_lock, &lockstate); 5270 obj = dlcheck(arg); 5271 if (obj == NULL) 5272 obj = obj_from_addr(arg); 5273 if (obj == NULL) { 5274 _rtld_error("No shared object contains address"); 5275 lock_release(rtld_bind_lock, &lockstate); 5276 return (-1); 5277 } 5278 res = obj->dlopened ? 1 : 0; 5279 lock_release(rtld_bind_lock, &lockstate); 5280 return (res); 5281 } 5282 5283 int 5284 obj_enforce_relro(Obj_Entry *obj) 5285 { 5286 5287 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5288 PROT_READ) == -1) { 5289 _rtld_error("%s: Cannot enforce relro protection: %s", 5290 obj->path, rtld_strerror(errno)); 5291 return (-1); 5292 } 5293 return (0); 5294 } 5295 5296 static void 5297 map_stacks_exec(RtldLockState *lockstate) 5298 { 5299 void (*thr_map_stacks_exec)(void); 5300 5301 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5302 return; 5303 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5304 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5305 if (thr_map_stacks_exec != NULL) { 5306 stack_prot |= PROT_EXEC; 5307 thr_map_stacks_exec(); 5308 } 5309 } 5310 5311 void 5312 symlook_init(SymLook *dst, const char *name) 5313 { 5314 5315 bzero(dst, sizeof(*dst)); 5316 dst->name = name; 5317 dst->hash = elf_hash(name); 5318 dst->hash_gnu = gnu_hash(name); 5319 } 5320 5321 static void 5322 symlook_init_from_req(SymLook *dst, const SymLook *src) 5323 { 5324 5325 dst->name = src->name; 5326 dst->hash = src->hash; 5327 dst->hash_gnu = src->hash_gnu; 5328 dst->ventry = src->ventry; 5329 dst->flags = src->flags; 5330 dst->defobj_out = NULL; 5331 dst->sym_out = NULL; 5332 dst->lockstate = src->lockstate; 5333 } 5334 5335 static int 5336 open_binary_fd(const char *argv0, bool search_in_path) 5337 { 5338 char *pathenv, *pe, binpath[PATH_MAX]; 5339 int fd; 5340 5341 if (search_in_path && strchr(argv0, '/') == NULL) { 5342 pathenv = getenv("PATH"); 5343 if (pathenv == NULL) { 5344 rtld_printf("-p and no PATH environment variable\n"); 5345 rtld_die(); 5346 } 5347 pathenv = strdup(pathenv); 5348 if (pathenv == NULL) { 5349 rtld_printf("Cannot allocate memory\n"); 5350 rtld_die(); 5351 } 5352 fd = -1; 5353 errno = ENOENT; 5354 while ((pe = strsep(&pathenv, ":")) != NULL) { 5355 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5356 sizeof(binpath)) 5357 continue; 5358 if (binpath[0] != '\0' && 5359 strlcat(binpath, "/", sizeof(binpath)) >= 5360 sizeof(binpath)) 5361 continue; 5362 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5363 sizeof(binpath)) 5364 continue; 5365 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5366 if (fd != -1 || errno != ENOENT) 5367 break; 5368 } 5369 free(pathenv); 5370 } else { 5371 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5372 } 5373 5374 if (fd == -1) { 5375 rtld_printf("Opening %s: %s\n", argv0, 5376 rtld_strerror(errno)); 5377 rtld_die(); 5378 } 5379 return (fd); 5380 } 5381 5382 /* 5383 * Parse a set of command-line arguments. 5384 */ 5385 static int 5386 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5387 { 5388 const char *arg; 5389 int fd, i, j, arglen; 5390 char opt; 5391 5392 dbg("Parsing command-line arguments"); 5393 *use_pathp = false; 5394 *fdp = -1; 5395 5396 for (i = 1; i < argc; i++ ) { 5397 arg = argv[i]; 5398 dbg("argv[%d]: '%s'", i, arg); 5399 5400 /* 5401 * rtld arguments end with an explicit "--" or with the first 5402 * non-prefixed argument. 5403 */ 5404 if (strcmp(arg, "--") == 0) { 5405 i++; 5406 break; 5407 } 5408 if (arg[0] != '-') 5409 break; 5410 5411 /* 5412 * All other arguments are single-character options that can 5413 * be combined, so we need to search through `arg` for them. 5414 */ 5415 arglen = strlen(arg); 5416 for (j = 1; j < arglen; j++) { 5417 opt = arg[j]; 5418 if (opt == 'h') { 5419 print_usage(argv[0]); 5420 rtld_die(); 5421 } else if (opt == 'f') { 5422 /* 5423 * -f XX can be used to specify a descriptor for the 5424 * binary named at the command line (i.e., the later 5425 * argument will specify the process name but the 5426 * descriptor is what will actually be executed) 5427 */ 5428 if (j != arglen - 1) { 5429 /* -f must be the last option in, e.g., -abcf */ 5430 _rtld_error("invalid options: %s", arg); 5431 rtld_die(); 5432 } 5433 i++; 5434 fd = parse_integer(argv[i]); 5435 if (fd == -1) { 5436 _rtld_error("invalid file descriptor: '%s'", 5437 argv[i]); 5438 rtld_die(); 5439 } 5440 *fdp = fd; 5441 break; 5442 } else if (opt == 'p') { 5443 *use_pathp = true; 5444 } else { 5445 rtld_printf("invalid argument: '%s'\n", arg); 5446 print_usage(argv[0]); 5447 rtld_die(); 5448 } 5449 } 5450 } 5451 5452 return (i); 5453 } 5454 5455 /* 5456 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5457 */ 5458 static int 5459 parse_integer(const char *str) 5460 { 5461 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5462 const char *orig; 5463 int n; 5464 char c; 5465 5466 orig = str; 5467 n = 0; 5468 for (c = *str; c != '\0'; c = *++str) { 5469 if (c < '0' || c > '9') 5470 return (-1); 5471 5472 n *= RADIX; 5473 n += c - '0'; 5474 } 5475 5476 /* Make sure we actually parsed something. */ 5477 if (str == orig) 5478 return (-1); 5479 return (n); 5480 } 5481 5482 static void 5483 print_usage(const char *argv0) 5484 { 5485 5486 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5487 "\n" 5488 "Options:\n" 5489 " -h Display this help message\n" 5490 " -p Search in PATH for named binary\n" 5491 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5492 " -- End of RTLD options\n" 5493 " <binary> Name of process to execute\n" 5494 " <args> Arguments to the executed process\n", argv0); 5495 } 5496 5497 /* 5498 * Overrides for libc_pic-provided functions. 5499 */ 5500 5501 int 5502 __getosreldate(void) 5503 { 5504 size_t len; 5505 int oid[2]; 5506 int error, osrel; 5507 5508 if (osreldate != 0) 5509 return (osreldate); 5510 5511 oid[0] = CTL_KERN; 5512 oid[1] = KERN_OSRELDATE; 5513 osrel = 0; 5514 len = sizeof(osrel); 5515 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5516 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5517 osreldate = osrel; 5518 return (osreldate); 5519 } 5520 5521 void 5522 exit(int status) 5523 { 5524 5525 _exit(status); 5526 } 5527 5528 void (*__cleanup)(void); 5529 int __isthreaded = 0; 5530 int _thread_autoinit_dummy_decl = 1; 5531 5532 /* 5533 * No unresolved symbols for rtld. 5534 */ 5535 void 5536 __pthread_cxa_finalize(struct dl_phdr_info *a) 5537 { 5538 } 5539 5540 void 5541 __stack_chk_fail(void) 5542 { 5543 5544 _rtld_error("stack overflow detected; terminated"); 5545 rtld_die(); 5546 } 5547 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5548 5549 void 5550 __chk_fail(void) 5551 { 5552 5553 _rtld_error("buffer overflow detected; terminated"); 5554 rtld_die(); 5555 } 5556 5557 const char * 5558 rtld_strerror(int errnum) 5559 { 5560 5561 if (errnum < 0 || errnum >= sys_nerr) 5562 return ("Unknown error"); 5563 return (sys_errlist[errnum]); 5564 } 5565