1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <[email protected]>. 4 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 5 * Copyright 2012 John Marino <[email protected]>. 6 * Copyright 2014-2017 The FreeBSD Foundation 7 * All rights reserved. 8 * 9 * Portions of this software were developed by Konstantin Belousov 10 * under sponsorship from the FreeBSD Foundation. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Dynamic linker for ELF. 35 * 36 * John Polstra <[email protected]>. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <sys/param.h> 43 #include <sys/mount.h> 44 #include <sys/mman.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/uio.h> 48 #include <sys/utsname.h> 49 #include <sys/ktrace.h> 50 51 #include <dlfcn.h> 52 #include <err.h> 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <stdarg.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 #include "debug.h" 62 #include "rtld.h" 63 #include "libmap.h" 64 #include "paths.h" 65 #include "rtld_tls.h" 66 #include "rtld_printf.h" 67 #include "rtld_utrace.h" 68 #include "notes.h" 69 70 /* Types. */ 71 typedef void (*func_ptr_type)(); 72 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 73 74 /* 75 * Function declarations. 76 */ 77 static const char *basename(const char *); 78 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 79 const Elf_Dyn **, const Elf_Dyn **); 80 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 81 const Elf_Dyn *); 82 static void digest_dynamic(Obj_Entry *, int); 83 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 84 static Obj_Entry *dlcheck(void *); 85 static int dlclose_locked(void *, RtldLockState *); 86 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 87 int lo_flags, int mode, RtldLockState *lockstate); 88 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 89 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 90 static bool donelist_check(DoneList *, const Obj_Entry *); 91 static void errmsg_restore(char *); 92 static char *errmsg_save(void); 93 static void *fill_search_info(const char *, size_t, void *); 94 static char *find_library(const char *, const Obj_Entry *, int *); 95 static const char *gethints(bool); 96 static void hold_object(Obj_Entry *); 97 static void unhold_object(Obj_Entry *); 98 static void init_dag(Obj_Entry *); 99 static void init_marker(Obj_Entry *); 100 static void init_pagesizes(Elf_Auxinfo **aux_info); 101 static void init_rtld(caddr_t, Elf_Auxinfo **); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *, RtldLockState *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static int obj_enforce_relro(Obj_Entry *); 113 static Obj_Entry *obj_from_addr(const void *); 114 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 115 static void objlist_call_init(Objlist *, RtldLockState *); 116 static void objlist_clear(Objlist *); 117 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 118 static void objlist_init(Objlist *); 119 static void objlist_push_head(Objlist *, Obj_Entry *); 120 static void objlist_push_tail(Objlist *, Obj_Entry *); 121 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 122 static void objlist_remove(Objlist *, Obj_Entry *); 123 static int open_binary_fd(const char *argv0, bool search_in_path); 124 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 125 static int parse_integer(const char *); 126 static void *path_enumerate(const char *, path_enum_proc, void *); 127 static void print_usage(const char *argv0); 128 static void release_object(Obj_Entry *); 129 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 130 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 131 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 132 int flags, RtldLockState *lockstate); 133 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 134 RtldLockState *); 135 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 136 int flags, RtldLockState *lockstate); 137 static int rtld_dirname(const char *, char *); 138 static int rtld_dirname_abs(const char *, char *); 139 static void *rtld_dlopen(const char *name, int fd, int mode); 140 static void rtld_exit(void); 141 static char *search_library_path(const char *, const char *); 142 static char *search_library_pathfds(const char *, const char *, int *); 143 static const void **get_program_var_addr(const char *, RtldLockState *); 144 static void set_program_var(const char *, const void *); 145 static int symlook_default(SymLook *, const Obj_Entry *refobj); 146 static int symlook_global(SymLook *, DoneList *); 147 static void symlook_init_from_req(SymLook *, const SymLook *); 148 static int symlook_list(SymLook *, const Objlist *, DoneList *); 149 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 150 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 151 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 152 static void trace_loaded_objects(Obj_Entry *); 153 static void unlink_object(Obj_Entry *); 154 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 155 static void unref_dag(Obj_Entry *); 156 static void ref_dag(Obj_Entry *); 157 static char *origin_subst_one(Obj_Entry *, char *, const char *, 158 const char *, bool); 159 static char *origin_subst(Obj_Entry *, char *); 160 static bool obj_resolve_origin(Obj_Entry *obj); 161 static void preinit_main(void); 162 static int rtld_verify_versions(const Objlist *); 163 static int rtld_verify_object_versions(Obj_Entry *); 164 static void object_add_name(Obj_Entry *, const char *); 165 static int object_match_name(const Obj_Entry *, const char *); 166 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 167 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 168 struct dl_phdr_info *phdr_info); 169 static uint32_t gnu_hash(const char *); 170 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 171 const unsigned long); 172 173 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 174 void _r_debug_postinit(struct link_map *) __noinline __exported; 175 176 int __sys_openat(int, const char *, int, ...); 177 178 /* 179 * Data declarations. 180 */ 181 static char *error_message; /* Message for dlerror(), or NULL */ 182 struct r_debug r_debug __exported; /* for GDB; */ 183 static bool libmap_disable; /* Disable libmap */ 184 static bool ld_loadfltr; /* Immediate filters processing */ 185 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 186 static bool trust; /* False for setuid and setgid programs */ 187 static bool dangerous_ld_env; /* True if environment variables have been 188 used to affect the libraries loaded */ 189 bool ld_bind_not; /* Disable PLT update */ 190 static char *ld_bind_now; /* Environment variable for immediate binding */ 191 static char *ld_debug; /* Environment variable for debugging */ 192 static char *ld_library_path; /* Environment variable for search path */ 193 static char *ld_library_dirs; /* Environment variable for library descriptors */ 194 static char *ld_preload; /* Environment variable for libraries to 195 load first */ 196 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 197 static char *ld_tracing; /* Called from ldd to print libs */ 198 static char *ld_utrace; /* Use utrace() to log events. */ 199 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 200 static Obj_Entry *obj_main; /* The main program shared object */ 201 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 202 static unsigned int obj_count; /* Number of objects in obj_list */ 203 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 204 205 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 206 STAILQ_HEAD_INITIALIZER(list_global); 207 static Objlist list_main = /* Objects loaded at program startup */ 208 STAILQ_HEAD_INITIALIZER(list_main); 209 static Objlist list_fini = /* Objects needing fini() calls */ 210 STAILQ_HEAD_INITIALIZER(list_fini); 211 212 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 213 214 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 215 216 extern Elf_Dyn _DYNAMIC; 217 #pragma weak _DYNAMIC 218 219 int dlclose(void *) __exported; 220 char *dlerror(void) __exported; 221 void *dlopen(const char *, int) __exported; 222 void *fdlopen(int, int) __exported; 223 void *dlsym(void *, const char *) __exported; 224 dlfunc_t dlfunc(void *, const char *) __exported; 225 void *dlvsym(void *, const char *, const char *) __exported; 226 int dladdr(const void *, Dl_info *) __exported; 227 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 228 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 229 int dlinfo(void *, int , void *) __exported; 230 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 231 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 232 int _rtld_get_stack_prot(void) __exported; 233 int _rtld_is_dlopened(void *) __exported; 234 void _rtld_error(const char *, ...) __exported; 235 236 int npagesizes, osreldate; 237 size_t *pagesizes; 238 239 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 240 241 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 242 static int max_stack_flags; 243 244 /* 245 * Global declarations normally provided by crt1. The dynamic linker is 246 * not built with crt1, so we have to provide them ourselves. 247 */ 248 char *__progname; 249 char **environ; 250 251 /* 252 * Used to pass argc, argv to init functions. 253 */ 254 int main_argc; 255 char **main_argv; 256 257 /* 258 * Globals to control TLS allocation. 259 */ 260 size_t tls_last_offset; /* Static TLS offset of last module */ 261 size_t tls_last_size; /* Static TLS size of last module */ 262 size_t tls_static_space; /* Static TLS space allocated */ 263 size_t tls_static_max_align; 264 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 265 int tls_max_index = 1; /* Largest module index allocated */ 266 267 bool ld_library_path_rpath = false; 268 269 /* 270 * Globals for path names, and such 271 */ 272 char *ld_elf_hints_default = _PATH_ELF_HINTS; 273 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 274 char *ld_path_rtld = _PATH_RTLD; 275 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 276 char *ld_env_prefix = LD_; 277 278 /* 279 * Fill in a DoneList with an allocation large enough to hold all of 280 * the currently-loaded objects. Keep this as a macro since it calls 281 * alloca and we want that to occur within the scope of the caller. 282 */ 283 #define donelist_init(dlp) \ 284 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 285 assert((dlp)->objs != NULL), \ 286 (dlp)->num_alloc = obj_count, \ 287 (dlp)->num_used = 0) 288 289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 290 if (ld_utrace != NULL) \ 291 ld_utrace_log(e, h, mb, ms, r, n); \ 292 } while (0) 293 294 static void 295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 296 int refcnt, const char *name) 297 { 298 struct utrace_rtld ut; 299 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 300 301 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 302 ut.event = event; 303 ut.handle = handle; 304 ut.mapbase = mapbase; 305 ut.mapsize = mapsize; 306 ut.refcnt = refcnt; 307 bzero(ut.name, sizeof(ut.name)); 308 if (name) 309 strlcpy(ut.name, name, sizeof(ut.name)); 310 utrace(&ut, sizeof(ut)); 311 } 312 313 #ifdef RTLD_VARIANT_ENV_NAMES 314 /* 315 * construct the env variable based on the type of binary that's 316 * running. 317 */ 318 static inline const char * 319 _LD(const char *var) 320 { 321 static char buffer[128]; 322 323 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 324 strlcat(buffer, var, sizeof(buffer)); 325 return (buffer); 326 } 327 #else 328 #define _LD(x) LD_ x 329 #endif 330 331 /* 332 * Main entry point for dynamic linking. The first argument is the 333 * stack pointer. The stack is expected to be laid out as described 334 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 335 * Specifically, the stack pointer points to a word containing 336 * ARGC. Following that in the stack is a null-terminated sequence 337 * of pointers to argument strings. Then comes a null-terminated 338 * sequence of pointers to environment strings. Finally, there is a 339 * sequence of "auxiliary vector" entries. 340 * 341 * The second argument points to a place to store the dynamic linker's 342 * exit procedure pointer and the third to a place to store the main 343 * program's object. 344 * 345 * The return value is the main program's entry point. 346 */ 347 func_ptr_type 348 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 349 { 350 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 351 Objlist_Entry *entry; 352 Obj_Entry *last_interposer, *obj, *preload_tail; 353 const Elf_Phdr *phdr; 354 Objlist initlist; 355 RtldLockState lockstate; 356 struct stat st; 357 Elf_Addr *argcp; 358 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 359 caddr_t imgentry; 360 char buf[MAXPATHLEN]; 361 int argc, fd, i, mib[2], phnum, rtld_argc; 362 size_t len; 363 bool dir_enable, explicit_fd, search_in_path; 364 365 /* 366 * On entry, the dynamic linker itself has not been relocated yet. 367 * Be very careful not to reference any global data until after 368 * init_rtld has returned. It is OK to reference file-scope statics 369 * and string constants, and to call static and global functions. 370 */ 371 372 /* Find the auxiliary vector on the stack. */ 373 argcp = sp; 374 argc = *sp++; 375 argv = (char **) sp; 376 sp += argc + 1; /* Skip over arguments and NULL terminator */ 377 env = (char **) sp; 378 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 379 ; 380 aux = (Elf_Auxinfo *) sp; 381 382 /* Digest the auxiliary vector. */ 383 for (i = 0; i < AT_COUNT; i++) 384 aux_info[i] = NULL; 385 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 386 if (auxp->a_type < AT_COUNT) 387 aux_info[auxp->a_type] = auxp; 388 } 389 390 /* Initialize and relocate ourselves. */ 391 assert(aux_info[AT_BASE] != NULL); 392 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 393 394 __progname = obj_rtld.path; 395 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 396 environ = env; 397 main_argc = argc; 398 main_argv = argv; 399 400 if (aux_info[AT_CANARY] != NULL && 401 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 402 i = aux_info[AT_CANARYLEN]->a_un.a_val; 403 if (i > sizeof(__stack_chk_guard)) 404 i = sizeof(__stack_chk_guard); 405 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 406 } else { 407 mib[0] = CTL_KERN; 408 mib[1] = KERN_ARND; 409 410 len = sizeof(__stack_chk_guard); 411 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 412 len != sizeof(__stack_chk_guard)) { 413 /* If sysctl was unsuccessful, use the "terminator canary". */ 414 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 415 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 416 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 417 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 418 } 419 } 420 421 trust = !issetugid(); 422 423 md_abi_variant_hook(aux_info); 424 425 fd = -1; 426 if (aux_info[AT_EXECFD] != NULL) { 427 fd = aux_info[AT_EXECFD]->a_un.a_val; 428 } else { 429 assert(aux_info[AT_PHDR] != NULL); 430 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 431 if (phdr == obj_rtld.phdr) { 432 if (!trust) { 433 rtld_printf("Tainted process refusing to run binary %s\n", 434 argv0); 435 rtld_die(); 436 } 437 dbg("opening main program in direct exec mode"); 438 if (argc >= 2) { 439 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 440 argv0 = argv[rtld_argc]; 441 explicit_fd = (fd != -1); 442 if (!explicit_fd) 443 fd = open_binary_fd(argv0, search_in_path); 444 if (fstat(fd, &st) == -1) { 445 _rtld_error("failed to fstat FD %d (%s): %s", fd, 446 explicit_fd ? "user-provided descriptor" : argv0, 447 rtld_strerror(errno)); 448 rtld_die(); 449 } 450 451 /* 452 * Rough emulation of the permission checks done by 453 * execve(2), only Unix DACs are checked, ACLs are 454 * ignored. Preserve the semantic of disabling owner 455 * to execute if owner x bit is cleared, even if 456 * others x bit is enabled. 457 * mmap(2) does not allow to mmap with PROT_EXEC if 458 * binary' file comes from noexec mount. We cannot 459 * set VV_TEXT on the binary. 460 */ 461 dir_enable = false; 462 if (st.st_uid == geteuid()) { 463 if ((st.st_mode & S_IXUSR) != 0) 464 dir_enable = true; 465 } else if (st.st_gid == getegid()) { 466 if ((st.st_mode & S_IXGRP) != 0) 467 dir_enable = true; 468 } else if ((st.st_mode & S_IXOTH) != 0) { 469 dir_enable = true; 470 } 471 if (!dir_enable) { 472 rtld_printf("No execute permission for binary %s\n", 473 argv0); 474 rtld_die(); 475 } 476 477 /* 478 * For direct exec mode, argv[0] is the interpreter 479 * name, we must remove it and shift arguments left 480 * before invoking binary main. Since stack layout 481 * places environment pointers and aux vectors right 482 * after the terminating NULL, we must shift 483 * environment and aux as well. 484 */ 485 main_argc = argc - rtld_argc; 486 for (i = 0; i <= main_argc; i++) 487 argv[i] = argv[i + rtld_argc]; 488 *argcp -= rtld_argc; 489 environ = env = envp = argv + main_argc + 1; 490 do { 491 *envp = *(envp + rtld_argc); 492 envp++; 493 } while (*envp != NULL); 494 aux = auxp = (Elf_Auxinfo *)envp; 495 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 496 for (;; auxp++, auxpf++) { 497 *auxp = *auxpf; 498 if (auxp->a_type == AT_NULL) 499 break; 500 } 501 } else { 502 rtld_printf("no binary\n"); 503 rtld_die(); 504 } 505 } 506 } 507 508 ld_bind_now = getenv(_LD("BIND_NOW")); 509 510 /* 511 * If the process is tainted, then we un-set the dangerous environment 512 * variables. The process will be marked as tainted until setuid(2) 513 * is called. If any child process calls setuid(2) we do not want any 514 * future processes to honor the potentially un-safe variables. 515 */ 516 if (!trust) { 517 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 518 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 519 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 520 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 521 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 522 _rtld_error("environment corrupt; aborting"); 523 rtld_die(); 524 } 525 } 526 ld_debug = getenv(_LD("DEBUG")); 527 if (ld_bind_now == NULL) 528 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 529 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 530 libmap_override = getenv(_LD("LIBMAP")); 531 ld_library_path = getenv(_LD("LIBRARY_PATH")); 532 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 533 ld_preload = getenv(_LD("PRELOAD")); 534 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 535 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 536 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 537 if (library_path_rpath != NULL) { 538 if (library_path_rpath[0] == 'y' || 539 library_path_rpath[0] == 'Y' || 540 library_path_rpath[0] == '1') 541 ld_library_path_rpath = true; 542 else 543 ld_library_path_rpath = false; 544 } 545 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 546 (ld_library_path != NULL) || (ld_preload != NULL) || 547 (ld_elf_hints_path != NULL) || ld_loadfltr; 548 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 549 ld_utrace = getenv(_LD("UTRACE")); 550 551 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 552 ld_elf_hints_path = ld_elf_hints_default; 553 554 if (ld_debug != NULL && *ld_debug != '\0') 555 debug = 1; 556 dbg("%s is initialized, base address = %p", __progname, 557 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 558 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 559 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 560 561 dbg("initializing thread locks"); 562 lockdflt_init(); 563 564 /* 565 * Load the main program, or process its program header if it is 566 * already loaded. 567 */ 568 if (fd != -1) { /* Load the main program. */ 569 dbg("loading main program"); 570 obj_main = map_object(fd, argv0, NULL); 571 close(fd); 572 if (obj_main == NULL) 573 rtld_die(); 574 max_stack_flags = obj_main->stack_flags; 575 } else { /* Main program already loaded. */ 576 dbg("processing main program's program header"); 577 assert(aux_info[AT_PHDR] != NULL); 578 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 579 assert(aux_info[AT_PHNUM] != NULL); 580 phnum = aux_info[AT_PHNUM]->a_un.a_val; 581 assert(aux_info[AT_PHENT] != NULL); 582 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 583 assert(aux_info[AT_ENTRY] != NULL); 584 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 585 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 586 rtld_die(); 587 } 588 589 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 590 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 591 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 592 if (kexecpath[0] == '/') 593 obj_main->path = kexecpath; 594 else if (getcwd(buf, sizeof(buf)) == NULL || 595 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 596 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 597 obj_main->path = xstrdup(argv0); 598 else 599 obj_main->path = xstrdup(buf); 600 } else { 601 dbg("No AT_EXECPATH or direct exec"); 602 obj_main->path = xstrdup(argv0); 603 } 604 dbg("obj_main path %s", obj_main->path); 605 obj_main->mainprog = true; 606 607 if (aux_info[AT_STACKPROT] != NULL && 608 aux_info[AT_STACKPROT]->a_un.a_val != 0) 609 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 610 611 #ifndef COMPAT_32BIT 612 /* 613 * Get the actual dynamic linker pathname from the executable if 614 * possible. (It should always be possible.) That ensures that 615 * gdb will find the right dynamic linker even if a non-standard 616 * one is being used. 617 */ 618 if (obj_main->interp != NULL && 619 strcmp(obj_main->interp, obj_rtld.path) != 0) { 620 free(obj_rtld.path); 621 obj_rtld.path = xstrdup(obj_main->interp); 622 __progname = obj_rtld.path; 623 } 624 #endif 625 626 digest_dynamic(obj_main, 0); 627 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 628 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 629 obj_main->dynsymcount); 630 631 linkmap_add(obj_main); 632 linkmap_add(&obj_rtld); 633 634 /* Link the main program into the list of objects. */ 635 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 636 obj_count++; 637 obj_loads++; 638 639 /* Initialize a fake symbol for resolving undefined weak references. */ 640 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 641 sym_zero.st_shndx = SHN_UNDEF; 642 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 643 644 if (!libmap_disable) 645 libmap_disable = (bool)lm_init(libmap_override); 646 647 dbg("loading LD_PRELOAD libraries"); 648 if (load_preload_objects() == -1) 649 rtld_die(); 650 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 651 652 dbg("loading needed objects"); 653 if (load_needed_objects(obj_main, 0) == -1) 654 rtld_die(); 655 656 /* Make a list of all objects loaded at startup. */ 657 last_interposer = obj_main; 658 TAILQ_FOREACH(obj, &obj_list, next) { 659 if (obj->marker) 660 continue; 661 if (obj->z_interpose && obj != obj_main) { 662 objlist_put_after(&list_main, last_interposer, obj); 663 last_interposer = obj; 664 } else { 665 objlist_push_tail(&list_main, obj); 666 } 667 obj->refcount++; 668 } 669 670 dbg("checking for required versions"); 671 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 672 rtld_die(); 673 674 if (ld_tracing) { /* We're done */ 675 trace_loaded_objects(obj_main); 676 exit(0); 677 } 678 679 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 680 dump_relocations(obj_main); 681 exit (0); 682 } 683 684 /* 685 * Processing tls relocations requires having the tls offsets 686 * initialized. Prepare offsets before starting initial 687 * relocation processing. 688 */ 689 dbg("initializing initial thread local storage offsets"); 690 STAILQ_FOREACH(entry, &list_main, link) { 691 /* 692 * Allocate all the initial objects out of the static TLS 693 * block even if they didn't ask for it. 694 */ 695 allocate_tls_offset(entry->obj); 696 } 697 698 if (relocate_objects(obj_main, 699 ld_bind_now != NULL && *ld_bind_now != '\0', 700 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 701 rtld_die(); 702 703 dbg("doing copy relocations"); 704 if (do_copy_relocations(obj_main) == -1) 705 rtld_die(); 706 707 dbg("enforcing main obj relro"); 708 if (obj_enforce_relro(obj_main) == -1) 709 rtld_die(); 710 711 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 712 dump_relocations(obj_main); 713 exit (0); 714 } 715 716 /* 717 * Setup TLS for main thread. This must be done after the 718 * relocations are processed, since tls initialization section 719 * might be the subject for relocations. 720 */ 721 dbg("initializing initial thread local storage"); 722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 723 724 dbg("initializing key program variables"); 725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 726 set_program_var("environ", env); 727 set_program_var("__elf_aux_vector", aux); 728 729 /* Make a list of init functions to call. */ 730 objlist_init(&initlist); 731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 732 preload_tail, &initlist); 733 734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 735 736 map_stacks_exec(NULL); 737 ifunc_init(aux); 738 739 dbg("resolving ifuncs"); 740 if (resolve_objects_ifunc(obj_main, 741 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 742 NULL) == -1) 743 rtld_die(); 744 745 if (!obj_main->crt_no_init) { 746 /* 747 * Make sure we don't call the main program's init and fini 748 * functions for binaries linked with old crt1 which calls 749 * _init itself. 750 */ 751 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 752 obj_main->preinit_array = obj_main->init_array = 753 obj_main->fini_array = (Elf_Addr)NULL; 754 } 755 756 wlock_acquire(rtld_bind_lock, &lockstate); 757 if (obj_main->crt_no_init) 758 preinit_main(); 759 objlist_call_init(&initlist, &lockstate); 760 _r_debug_postinit(&obj_main->linkmap); 761 objlist_clear(&initlist); 762 dbg("loading filtees"); 763 TAILQ_FOREACH(obj, &obj_list, next) { 764 if (obj->marker) 765 continue; 766 if (ld_loadfltr || obj->z_loadfltr) 767 load_filtees(obj, 0, &lockstate); 768 } 769 lock_release(rtld_bind_lock, &lockstate); 770 771 dbg("transferring control to program entry point = %p", obj_main->entry); 772 773 /* Return the exit procedure and the program entry point. */ 774 *exit_proc = rtld_exit; 775 *objp = obj_main; 776 return (func_ptr_type) obj_main->entry; 777 } 778 779 void * 780 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 781 { 782 void *ptr; 783 Elf_Addr target; 784 785 ptr = (void *)make_function_pointer(def, obj); 786 target = call_ifunc_resolver(ptr); 787 return ((void *)target); 788 } 789 790 /* 791 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 792 * Changes to this function should be applied there as well. 793 */ 794 Elf_Addr 795 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 796 { 797 const Elf_Rel *rel; 798 const Elf_Sym *def; 799 const Obj_Entry *defobj; 800 Elf_Addr *where; 801 Elf_Addr target; 802 RtldLockState lockstate; 803 804 rlock_acquire(rtld_bind_lock, &lockstate); 805 if (sigsetjmp(lockstate.env, 0) != 0) 806 lock_upgrade(rtld_bind_lock, &lockstate); 807 if (obj->pltrel) 808 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 809 else 810 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 811 812 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 813 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 814 NULL, &lockstate); 815 if (def == NULL) 816 rtld_die(); 817 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 818 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 819 else 820 target = (Elf_Addr)(defobj->relocbase + def->st_value); 821 822 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 823 defobj->strtab + def->st_name, basename(obj->path), 824 (void *)target, basename(defobj->path)); 825 826 /* 827 * Write the new contents for the jmpslot. Note that depending on 828 * architecture, the value which we need to return back to the 829 * lazy binding trampoline may or may not be the target 830 * address. The value returned from reloc_jmpslot() is the value 831 * that the trampoline needs. 832 */ 833 target = reloc_jmpslot(where, target, defobj, obj, rel); 834 lock_release(rtld_bind_lock, &lockstate); 835 return target; 836 } 837 838 /* 839 * Error reporting function. Use it like printf. If formats the message 840 * into a buffer, and sets things up so that the next call to dlerror() 841 * will return the message. 842 */ 843 void 844 _rtld_error(const char *fmt, ...) 845 { 846 static char buf[512]; 847 va_list ap; 848 849 va_start(ap, fmt); 850 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 851 error_message = buf; 852 va_end(ap); 853 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 854 } 855 856 /* 857 * Return a dynamically-allocated copy of the current error message, if any. 858 */ 859 static char * 860 errmsg_save(void) 861 { 862 return error_message == NULL ? NULL : xstrdup(error_message); 863 } 864 865 /* 866 * Restore the current error message from a copy which was previously saved 867 * by errmsg_save(). The copy is freed. 868 */ 869 static void 870 errmsg_restore(char *saved_msg) 871 { 872 if (saved_msg == NULL) 873 error_message = NULL; 874 else { 875 _rtld_error("%s", saved_msg); 876 free(saved_msg); 877 } 878 } 879 880 static const char * 881 basename(const char *name) 882 { 883 const char *p = strrchr(name, '/'); 884 return p != NULL ? p + 1 : name; 885 } 886 887 static struct utsname uts; 888 889 static char * 890 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 891 const char *subst, bool may_free) 892 { 893 char *p, *p1, *res, *resp; 894 int subst_len, kw_len, subst_count, old_len, new_len; 895 896 kw_len = strlen(kw); 897 898 /* 899 * First, count the number of the keyword occurrences, to 900 * preallocate the final string. 901 */ 902 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 903 p1 = strstr(p, kw); 904 if (p1 == NULL) 905 break; 906 } 907 908 /* 909 * If the keyword is not found, just return. 910 * 911 * Return non-substituted string if resolution failed. We 912 * cannot do anything more reasonable, the failure mode of the 913 * caller is unresolved library anyway. 914 */ 915 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 916 return (may_free ? real : xstrdup(real)); 917 if (obj != NULL) 918 subst = obj->origin_path; 919 920 /* 921 * There is indeed something to substitute. Calculate the 922 * length of the resulting string, and allocate it. 923 */ 924 subst_len = strlen(subst); 925 old_len = strlen(real); 926 new_len = old_len + (subst_len - kw_len) * subst_count; 927 res = xmalloc(new_len + 1); 928 929 /* 930 * Now, execute the substitution loop. 931 */ 932 for (p = real, resp = res, *resp = '\0';;) { 933 p1 = strstr(p, kw); 934 if (p1 != NULL) { 935 /* Copy the prefix before keyword. */ 936 memcpy(resp, p, p1 - p); 937 resp += p1 - p; 938 /* Keyword replacement. */ 939 memcpy(resp, subst, subst_len); 940 resp += subst_len; 941 *resp = '\0'; 942 p = p1 + kw_len; 943 } else 944 break; 945 } 946 947 /* Copy to the end of string and finish. */ 948 strcat(resp, p); 949 if (may_free) 950 free(real); 951 return (res); 952 } 953 954 static char * 955 origin_subst(Obj_Entry *obj, char *real) 956 { 957 char *res1, *res2, *res3, *res4; 958 959 if (obj == NULL || !trust) 960 return (xstrdup(real)); 961 if (uts.sysname[0] == '\0') { 962 if (uname(&uts) != 0) { 963 _rtld_error("utsname failed: %d", errno); 964 return (NULL); 965 } 966 } 967 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 968 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 969 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 970 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 971 return (res4); 972 } 973 974 void 975 rtld_die(void) 976 { 977 const char *msg = dlerror(); 978 979 if (msg == NULL) 980 msg = "Fatal error"; 981 rtld_fdputstr(STDERR_FILENO, msg); 982 rtld_fdputchar(STDERR_FILENO, '\n'); 983 _exit(1); 984 } 985 986 /* 987 * Process a shared object's DYNAMIC section, and save the important 988 * information in its Obj_Entry structure. 989 */ 990 static void 991 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 992 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 993 { 994 const Elf_Dyn *dynp; 995 Needed_Entry **needed_tail = &obj->needed; 996 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 997 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 998 const Elf_Hashelt *hashtab; 999 const Elf32_Word *hashval; 1000 Elf32_Word bkt, nmaskwords; 1001 int bloom_size32; 1002 int plttype = DT_REL; 1003 1004 *dyn_rpath = NULL; 1005 *dyn_soname = NULL; 1006 *dyn_runpath = NULL; 1007 1008 obj->bind_now = false; 1009 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1010 switch (dynp->d_tag) { 1011 1012 case DT_REL: 1013 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1014 break; 1015 1016 case DT_RELSZ: 1017 obj->relsize = dynp->d_un.d_val; 1018 break; 1019 1020 case DT_RELENT: 1021 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1022 break; 1023 1024 case DT_JMPREL: 1025 obj->pltrel = (const Elf_Rel *) 1026 (obj->relocbase + dynp->d_un.d_ptr); 1027 break; 1028 1029 case DT_PLTRELSZ: 1030 obj->pltrelsize = dynp->d_un.d_val; 1031 break; 1032 1033 case DT_RELA: 1034 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1035 break; 1036 1037 case DT_RELASZ: 1038 obj->relasize = dynp->d_un.d_val; 1039 break; 1040 1041 case DT_RELAENT: 1042 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1043 break; 1044 1045 case DT_PLTREL: 1046 plttype = dynp->d_un.d_val; 1047 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1048 break; 1049 1050 case DT_SYMTAB: 1051 obj->symtab = (const Elf_Sym *) 1052 (obj->relocbase + dynp->d_un.d_ptr); 1053 break; 1054 1055 case DT_SYMENT: 1056 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1057 break; 1058 1059 case DT_STRTAB: 1060 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1061 break; 1062 1063 case DT_STRSZ: 1064 obj->strsize = dynp->d_un.d_val; 1065 break; 1066 1067 case DT_VERNEED: 1068 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1069 dynp->d_un.d_val); 1070 break; 1071 1072 case DT_VERNEEDNUM: 1073 obj->verneednum = dynp->d_un.d_val; 1074 break; 1075 1076 case DT_VERDEF: 1077 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1078 dynp->d_un.d_val); 1079 break; 1080 1081 case DT_VERDEFNUM: 1082 obj->verdefnum = dynp->d_un.d_val; 1083 break; 1084 1085 case DT_VERSYM: 1086 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1087 dynp->d_un.d_val); 1088 break; 1089 1090 case DT_HASH: 1091 { 1092 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1093 dynp->d_un.d_ptr); 1094 obj->nbuckets = hashtab[0]; 1095 obj->nchains = hashtab[1]; 1096 obj->buckets = hashtab + 2; 1097 obj->chains = obj->buckets + obj->nbuckets; 1098 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1099 obj->buckets != NULL; 1100 } 1101 break; 1102 1103 case DT_GNU_HASH: 1104 { 1105 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1106 dynp->d_un.d_ptr); 1107 obj->nbuckets_gnu = hashtab[0]; 1108 obj->symndx_gnu = hashtab[1]; 1109 nmaskwords = hashtab[2]; 1110 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1111 obj->maskwords_bm_gnu = nmaskwords - 1; 1112 obj->shift2_gnu = hashtab[3]; 1113 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1114 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1115 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1116 obj->symndx_gnu; 1117 /* Number of bitmask words is required to be power of 2 */ 1118 obj->valid_hash_gnu = powerof2(nmaskwords) && 1119 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1120 } 1121 break; 1122 1123 case DT_NEEDED: 1124 if (!obj->rtld) { 1125 Needed_Entry *nep = NEW(Needed_Entry); 1126 nep->name = dynp->d_un.d_val; 1127 nep->obj = NULL; 1128 nep->next = NULL; 1129 1130 *needed_tail = nep; 1131 needed_tail = &nep->next; 1132 } 1133 break; 1134 1135 case DT_FILTER: 1136 if (!obj->rtld) { 1137 Needed_Entry *nep = NEW(Needed_Entry); 1138 nep->name = dynp->d_un.d_val; 1139 nep->obj = NULL; 1140 nep->next = NULL; 1141 1142 *needed_filtees_tail = nep; 1143 needed_filtees_tail = &nep->next; 1144 } 1145 break; 1146 1147 case DT_AUXILIARY: 1148 if (!obj->rtld) { 1149 Needed_Entry *nep = NEW(Needed_Entry); 1150 nep->name = dynp->d_un.d_val; 1151 nep->obj = NULL; 1152 nep->next = NULL; 1153 1154 *needed_aux_filtees_tail = nep; 1155 needed_aux_filtees_tail = &nep->next; 1156 } 1157 break; 1158 1159 case DT_PLTGOT: 1160 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1161 break; 1162 1163 case DT_TEXTREL: 1164 obj->textrel = true; 1165 break; 1166 1167 case DT_SYMBOLIC: 1168 obj->symbolic = true; 1169 break; 1170 1171 case DT_RPATH: 1172 /* 1173 * We have to wait until later to process this, because we 1174 * might not have gotten the address of the string table yet. 1175 */ 1176 *dyn_rpath = dynp; 1177 break; 1178 1179 case DT_SONAME: 1180 *dyn_soname = dynp; 1181 break; 1182 1183 case DT_RUNPATH: 1184 *dyn_runpath = dynp; 1185 break; 1186 1187 case DT_INIT: 1188 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1189 break; 1190 1191 case DT_PREINIT_ARRAY: 1192 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1193 break; 1194 1195 case DT_PREINIT_ARRAYSZ: 1196 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1197 break; 1198 1199 case DT_INIT_ARRAY: 1200 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1201 break; 1202 1203 case DT_INIT_ARRAYSZ: 1204 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1205 break; 1206 1207 case DT_FINI: 1208 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1209 break; 1210 1211 case DT_FINI_ARRAY: 1212 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1213 break; 1214 1215 case DT_FINI_ARRAYSZ: 1216 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1217 break; 1218 1219 /* 1220 * Don't process DT_DEBUG on MIPS as the dynamic section 1221 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1222 */ 1223 1224 #ifndef __mips__ 1225 case DT_DEBUG: 1226 if (!early) 1227 dbg("Filling in DT_DEBUG entry"); 1228 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1229 break; 1230 #endif 1231 1232 case DT_FLAGS: 1233 if (dynp->d_un.d_val & DF_ORIGIN) 1234 obj->z_origin = true; 1235 if (dynp->d_un.d_val & DF_SYMBOLIC) 1236 obj->symbolic = true; 1237 if (dynp->d_un.d_val & DF_TEXTREL) 1238 obj->textrel = true; 1239 if (dynp->d_un.d_val & DF_BIND_NOW) 1240 obj->bind_now = true; 1241 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1242 ;*/ 1243 break; 1244 #ifdef __mips__ 1245 case DT_MIPS_LOCAL_GOTNO: 1246 obj->local_gotno = dynp->d_un.d_val; 1247 break; 1248 1249 case DT_MIPS_SYMTABNO: 1250 obj->symtabno = dynp->d_un.d_val; 1251 break; 1252 1253 case DT_MIPS_GOTSYM: 1254 obj->gotsym = dynp->d_un.d_val; 1255 break; 1256 1257 case DT_MIPS_RLD_MAP: 1258 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1259 break; 1260 1261 case DT_MIPS_PLTGOT: 1262 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1263 dynp->d_un.d_ptr); 1264 break; 1265 1266 #endif 1267 1268 #ifdef __powerpc64__ 1269 case DT_PPC64_GLINK: 1270 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1271 break; 1272 #endif 1273 1274 case DT_FLAGS_1: 1275 if (dynp->d_un.d_val & DF_1_NOOPEN) 1276 obj->z_noopen = true; 1277 if (dynp->d_un.d_val & DF_1_ORIGIN) 1278 obj->z_origin = true; 1279 if (dynp->d_un.d_val & DF_1_GLOBAL) 1280 obj->z_global = true; 1281 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1282 obj->bind_now = true; 1283 if (dynp->d_un.d_val & DF_1_NODELETE) 1284 obj->z_nodelete = true; 1285 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1286 obj->z_loadfltr = true; 1287 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1288 obj->z_interpose = true; 1289 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1290 obj->z_nodeflib = true; 1291 break; 1292 1293 default: 1294 if (!early) { 1295 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1296 (long)dynp->d_tag); 1297 } 1298 break; 1299 } 1300 } 1301 1302 obj->traced = false; 1303 1304 if (plttype == DT_RELA) { 1305 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1306 obj->pltrel = NULL; 1307 obj->pltrelasize = obj->pltrelsize; 1308 obj->pltrelsize = 0; 1309 } 1310 1311 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1312 if (obj->valid_hash_sysv) 1313 obj->dynsymcount = obj->nchains; 1314 else if (obj->valid_hash_gnu) { 1315 obj->dynsymcount = 0; 1316 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1317 if (obj->buckets_gnu[bkt] == 0) 1318 continue; 1319 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1320 do 1321 obj->dynsymcount++; 1322 while ((*hashval++ & 1u) == 0); 1323 } 1324 obj->dynsymcount += obj->symndx_gnu; 1325 } 1326 } 1327 1328 static bool 1329 obj_resolve_origin(Obj_Entry *obj) 1330 { 1331 1332 if (obj->origin_path != NULL) 1333 return (true); 1334 obj->origin_path = xmalloc(PATH_MAX); 1335 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1336 } 1337 1338 static void 1339 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1340 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1341 { 1342 1343 if (obj->z_origin && !obj_resolve_origin(obj)) 1344 rtld_die(); 1345 1346 if (dyn_runpath != NULL) { 1347 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1348 obj->runpath = origin_subst(obj, obj->runpath); 1349 } else if (dyn_rpath != NULL) { 1350 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1351 obj->rpath = origin_subst(obj, obj->rpath); 1352 } 1353 if (dyn_soname != NULL) 1354 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1355 } 1356 1357 static void 1358 digest_dynamic(Obj_Entry *obj, int early) 1359 { 1360 const Elf_Dyn *dyn_rpath; 1361 const Elf_Dyn *dyn_soname; 1362 const Elf_Dyn *dyn_runpath; 1363 1364 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1365 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1366 } 1367 1368 /* 1369 * Process a shared object's program header. This is used only for the 1370 * main program, when the kernel has already loaded the main program 1371 * into memory before calling the dynamic linker. It creates and 1372 * returns an Obj_Entry structure. 1373 */ 1374 static Obj_Entry * 1375 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1376 { 1377 Obj_Entry *obj; 1378 const Elf_Phdr *phlimit = phdr + phnum; 1379 const Elf_Phdr *ph; 1380 Elf_Addr note_start, note_end; 1381 int nsegs = 0; 1382 1383 obj = obj_new(); 1384 for (ph = phdr; ph < phlimit; ph++) { 1385 if (ph->p_type != PT_PHDR) 1386 continue; 1387 1388 obj->phdr = phdr; 1389 obj->phsize = ph->p_memsz; 1390 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1391 break; 1392 } 1393 1394 obj->stack_flags = PF_X | PF_R | PF_W; 1395 1396 for (ph = phdr; ph < phlimit; ph++) { 1397 switch (ph->p_type) { 1398 1399 case PT_INTERP: 1400 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1401 break; 1402 1403 case PT_LOAD: 1404 if (nsegs == 0) { /* First load segment */ 1405 obj->vaddrbase = trunc_page(ph->p_vaddr); 1406 obj->mapbase = obj->vaddrbase + obj->relocbase; 1407 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1408 obj->vaddrbase; 1409 } else { /* Last load segment */ 1410 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1411 obj->vaddrbase; 1412 } 1413 nsegs++; 1414 break; 1415 1416 case PT_DYNAMIC: 1417 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1418 break; 1419 1420 case PT_TLS: 1421 obj->tlsindex = 1; 1422 obj->tlssize = ph->p_memsz; 1423 obj->tlsalign = ph->p_align; 1424 obj->tlsinitsize = ph->p_filesz; 1425 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1426 break; 1427 1428 case PT_GNU_STACK: 1429 obj->stack_flags = ph->p_flags; 1430 break; 1431 1432 case PT_GNU_RELRO: 1433 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1434 obj->relro_size = round_page(ph->p_memsz); 1435 break; 1436 1437 case PT_NOTE: 1438 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1439 note_end = note_start + ph->p_filesz; 1440 digest_notes(obj, note_start, note_end); 1441 break; 1442 } 1443 } 1444 if (nsegs < 1) { 1445 _rtld_error("%s: too few PT_LOAD segments", path); 1446 return NULL; 1447 } 1448 1449 obj->entry = entry; 1450 return obj; 1451 } 1452 1453 void 1454 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1455 { 1456 const Elf_Note *note; 1457 const char *note_name; 1458 uintptr_t p; 1459 1460 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1461 note = (const Elf_Note *)((const char *)(note + 1) + 1462 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1463 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1464 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1465 note->n_descsz != sizeof(int32_t)) 1466 continue; 1467 if (note->n_type != NT_FREEBSD_ABI_TAG && 1468 note->n_type != NT_FREEBSD_NOINIT_TAG) 1469 continue; 1470 note_name = (const char *)(note + 1); 1471 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1472 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1473 continue; 1474 switch (note->n_type) { 1475 case NT_FREEBSD_ABI_TAG: 1476 /* FreeBSD osrel note */ 1477 p = (uintptr_t)(note + 1); 1478 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1479 obj->osrel = *(const int32_t *)(p); 1480 dbg("note osrel %d", obj->osrel); 1481 break; 1482 case NT_FREEBSD_NOINIT_TAG: 1483 /* FreeBSD 'crt does not call init' note */ 1484 obj->crt_no_init = true; 1485 dbg("note crt_no_init"); 1486 break; 1487 } 1488 } 1489 } 1490 1491 static Obj_Entry * 1492 dlcheck(void *handle) 1493 { 1494 Obj_Entry *obj; 1495 1496 TAILQ_FOREACH(obj, &obj_list, next) { 1497 if (obj == (Obj_Entry *) handle) 1498 break; 1499 } 1500 1501 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1502 _rtld_error("Invalid shared object handle %p", handle); 1503 return NULL; 1504 } 1505 return obj; 1506 } 1507 1508 /* 1509 * If the given object is already in the donelist, return true. Otherwise 1510 * add the object to the list and return false. 1511 */ 1512 static bool 1513 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1514 { 1515 unsigned int i; 1516 1517 for (i = 0; i < dlp->num_used; i++) 1518 if (dlp->objs[i] == obj) 1519 return true; 1520 /* 1521 * Our donelist allocation should always be sufficient. But if 1522 * our threads locking isn't working properly, more shared objects 1523 * could have been loaded since we allocated the list. That should 1524 * never happen, but we'll handle it properly just in case it does. 1525 */ 1526 if (dlp->num_used < dlp->num_alloc) 1527 dlp->objs[dlp->num_used++] = obj; 1528 return false; 1529 } 1530 1531 /* 1532 * Hash function for symbol table lookup. Don't even think about changing 1533 * this. It is specified by the System V ABI. 1534 */ 1535 unsigned long 1536 elf_hash(const char *name) 1537 { 1538 const unsigned char *p = (const unsigned char *) name; 1539 unsigned long h = 0; 1540 unsigned long g; 1541 1542 while (*p != '\0') { 1543 h = (h << 4) + *p++; 1544 if ((g = h & 0xf0000000) != 0) 1545 h ^= g >> 24; 1546 h &= ~g; 1547 } 1548 return h; 1549 } 1550 1551 /* 1552 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1553 * unsigned in case it's implemented with a wider type. 1554 */ 1555 static uint32_t 1556 gnu_hash(const char *s) 1557 { 1558 uint32_t h; 1559 unsigned char c; 1560 1561 h = 5381; 1562 for (c = *s; c != '\0'; c = *++s) 1563 h = h * 33 + c; 1564 return (h & 0xffffffff); 1565 } 1566 1567 1568 /* 1569 * Find the library with the given name, and return its full pathname. 1570 * The returned string is dynamically allocated. Generates an error 1571 * message and returns NULL if the library cannot be found. 1572 * 1573 * If the second argument is non-NULL, then it refers to an already- 1574 * loaded shared object, whose library search path will be searched. 1575 * 1576 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1577 * descriptor (which is close-on-exec) will be passed out via the third 1578 * argument. 1579 * 1580 * The search order is: 1581 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1582 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1583 * LD_LIBRARY_PATH 1584 * DT_RUNPATH in the referencing file 1585 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1586 * from list) 1587 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1588 * 1589 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1590 */ 1591 static char * 1592 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1593 { 1594 char *pathname; 1595 char *name; 1596 bool nodeflib, objgiven; 1597 1598 objgiven = refobj != NULL; 1599 1600 if (libmap_disable || !objgiven || 1601 (name = lm_find(refobj->path, xname)) == NULL) 1602 name = (char *)xname; 1603 1604 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1605 if (name[0] != '/' && !trust) { 1606 _rtld_error("Absolute pathname required " 1607 "for shared object \"%s\"", name); 1608 return (NULL); 1609 } 1610 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1611 __DECONST(char *, name))); 1612 } 1613 1614 dbg(" Searching for \"%s\"", name); 1615 1616 /* 1617 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1618 * back to pre-conforming behaviour if user requested so with 1619 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1620 * nodeflib. 1621 */ 1622 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1623 pathname = search_library_path(name, ld_library_path); 1624 if (pathname != NULL) 1625 return (pathname); 1626 if (refobj != NULL) { 1627 pathname = search_library_path(name, refobj->rpath); 1628 if (pathname != NULL) 1629 return (pathname); 1630 } 1631 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1632 if (pathname != NULL) 1633 return (pathname); 1634 pathname = search_library_path(name, gethints(false)); 1635 if (pathname != NULL) 1636 return (pathname); 1637 pathname = search_library_path(name, ld_standard_library_path); 1638 if (pathname != NULL) 1639 return (pathname); 1640 } else { 1641 nodeflib = objgiven ? refobj->z_nodeflib : false; 1642 if (objgiven) { 1643 pathname = search_library_path(name, refobj->rpath); 1644 if (pathname != NULL) 1645 return (pathname); 1646 } 1647 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1648 pathname = search_library_path(name, obj_main->rpath); 1649 if (pathname != NULL) 1650 return (pathname); 1651 } 1652 pathname = search_library_path(name, ld_library_path); 1653 if (pathname != NULL) 1654 return (pathname); 1655 if (objgiven) { 1656 pathname = search_library_path(name, refobj->runpath); 1657 if (pathname != NULL) 1658 return (pathname); 1659 } 1660 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1661 if (pathname != NULL) 1662 return (pathname); 1663 pathname = search_library_path(name, gethints(nodeflib)); 1664 if (pathname != NULL) 1665 return (pathname); 1666 if (objgiven && !nodeflib) { 1667 pathname = search_library_path(name, 1668 ld_standard_library_path); 1669 if (pathname != NULL) 1670 return (pathname); 1671 } 1672 } 1673 1674 if (objgiven && refobj->path != NULL) { 1675 _rtld_error("Shared object \"%s\" not found, " 1676 "required by \"%s\"", name, basename(refobj->path)); 1677 } else { 1678 _rtld_error("Shared object \"%s\" not found", name); 1679 } 1680 return (NULL); 1681 } 1682 1683 /* 1684 * Given a symbol number in a referencing object, find the corresponding 1685 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1686 * no definition was found. Returns a pointer to the Obj_Entry of the 1687 * defining object via the reference parameter DEFOBJ_OUT. 1688 */ 1689 const Elf_Sym * 1690 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1691 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1692 RtldLockState *lockstate) 1693 { 1694 const Elf_Sym *ref; 1695 const Elf_Sym *def; 1696 const Obj_Entry *defobj; 1697 const Ver_Entry *ve; 1698 SymLook req; 1699 const char *name; 1700 int res; 1701 1702 /* 1703 * If we have already found this symbol, get the information from 1704 * the cache. 1705 */ 1706 if (symnum >= refobj->dynsymcount) 1707 return NULL; /* Bad object */ 1708 if (cache != NULL && cache[symnum].sym != NULL) { 1709 *defobj_out = cache[symnum].obj; 1710 return cache[symnum].sym; 1711 } 1712 1713 ref = refobj->symtab + symnum; 1714 name = refobj->strtab + ref->st_name; 1715 def = NULL; 1716 defobj = NULL; 1717 ve = NULL; 1718 1719 /* 1720 * We don't have to do a full scale lookup if the symbol is local. 1721 * We know it will bind to the instance in this load module; to 1722 * which we already have a pointer (ie ref). By not doing a lookup, 1723 * we not only improve performance, but it also avoids unresolvable 1724 * symbols when local symbols are not in the hash table. This has 1725 * been seen with the ia64 toolchain. 1726 */ 1727 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1728 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1729 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1730 symnum); 1731 } 1732 symlook_init(&req, name); 1733 req.flags = flags; 1734 ve = req.ventry = fetch_ventry(refobj, symnum); 1735 req.lockstate = lockstate; 1736 res = symlook_default(&req, refobj); 1737 if (res == 0) { 1738 def = req.sym_out; 1739 defobj = req.defobj_out; 1740 } 1741 } else { 1742 def = ref; 1743 defobj = refobj; 1744 } 1745 1746 /* 1747 * If we found no definition and the reference is weak, treat the 1748 * symbol as having the value zero. 1749 */ 1750 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1751 def = &sym_zero; 1752 defobj = obj_main; 1753 } 1754 1755 if (def != NULL) { 1756 *defobj_out = defobj; 1757 /* Record the information in the cache to avoid subsequent lookups. */ 1758 if (cache != NULL) { 1759 cache[symnum].sym = def; 1760 cache[symnum].obj = defobj; 1761 } 1762 } else { 1763 if (refobj != &obj_rtld) 1764 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1765 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1766 } 1767 return def; 1768 } 1769 1770 /* 1771 * Return the search path from the ldconfig hints file, reading it if 1772 * necessary. If nostdlib is true, then the default search paths are 1773 * not added to result. 1774 * 1775 * Returns NULL if there are problems with the hints file, 1776 * or if the search path there is empty. 1777 */ 1778 static const char * 1779 gethints(bool nostdlib) 1780 { 1781 static char *hints, *filtered_path; 1782 static struct elfhints_hdr hdr; 1783 struct fill_search_info_args sargs, hargs; 1784 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1785 struct dl_serpath *SLPpath, *hintpath; 1786 char *p; 1787 struct stat hint_stat; 1788 unsigned int SLPndx, hintndx, fndx, fcount; 1789 int fd; 1790 size_t flen; 1791 uint32_t dl; 1792 bool skip; 1793 1794 /* First call, read the hints file */ 1795 if (hints == NULL) { 1796 /* Keep from trying again in case the hints file is bad. */ 1797 hints = ""; 1798 1799 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1800 return (NULL); 1801 1802 /* 1803 * Check of hdr.dirlistlen value against type limit 1804 * intends to pacify static analyzers. Further 1805 * paranoia leads to checks that dirlist is fully 1806 * contained in the file range. 1807 */ 1808 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1809 hdr.magic != ELFHINTS_MAGIC || 1810 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1811 fstat(fd, &hint_stat) == -1) { 1812 cleanup1: 1813 close(fd); 1814 hdr.dirlistlen = 0; 1815 return (NULL); 1816 } 1817 dl = hdr.strtab; 1818 if (dl + hdr.dirlist < dl) 1819 goto cleanup1; 1820 dl += hdr.dirlist; 1821 if (dl + hdr.dirlistlen < dl) 1822 goto cleanup1; 1823 dl += hdr.dirlistlen; 1824 if (dl > hint_stat.st_size) 1825 goto cleanup1; 1826 p = xmalloc(hdr.dirlistlen + 1); 1827 1828 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1829 read(fd, p, hdr.dirlistlen + 1) != 1830 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1831 free(p); 1832 goto cleanup1; 1833 } 1834 hints = p; 1835 close(fd); 1836 } 1837 1838 /* 1839 * If caller agreed to receive list which includes the default 1840 * paths, we are done. Otherwise, if we still did not 1841 * calculated filtered result, do it now. 1842 */ 1843 if (!nostdlib) 1844 return (hints[0] != '\0' ? hints : NULL); 1845 if (filtered_path != NULL) 1846 goto filt_ret; 1847 1848 /* 1849 * Obtain the list of all configured search paths, and the 1850 * list of the default paths. 1851 * 1852 * First estimate the size of the results. 1853 */ 1854 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1855 smeta.dls_cnt = 0; 1856 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1857 hmeta.dls_cnt = 0; 1858 1859 sargs.request = RTLD_DI_SERINFOSIZE; 1860 sargs.serinfo = &smeta; 1861 hargs.request = RTLD_DI_SERINFOSIZE; 1862 hargs.serinfo = &hmeta; 1863 1864 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1865 path_enumerate(hints, fill_search_info, &hargs); 1866 1867 SLPinfo = xmalloc(smeta.dls_size); 1868 hintinfo = xmalloc(hmeta.dls_size); 1869 1870 /* 1871 * Next fetch both sets of paths. 1872 */ 1873 sargs.request = RTLD_DI_SERINFO; 1874 sargs.serinfo = SLPinfo; 1875 sargs.serpath = &SLPinfo->dls_serpath[0]; 1876 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1877 1878 hargs.request = RTLD_DI_SERINFO; 1879 hargs.serinfo = hintinfo; 1880 hargs.serpath = &hintinfo->dls_serpath[0]; 1881 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1882 1883 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1884 path_enumerate(hints, fill_search_info, &hargs); 1885 1886 /* 1887 * Now calculate the difference between two sets, by excluding 1888 * standard paths from the full set. 1889 */ 1890 fndx = 0; 1891 fcount = 0; 1892 filtered_path = xmalloc(hdr.dirlistlen + 1); 1893 hintpath = &hintinfo->dls_serpath[0]; 1894 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1895 skip = false; 1896 SLPpath = &SLPinfo->dls_serpath[0]; 1897 /* 1898 * Check each standard path against current. 1899 */ 1900 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1901 /* matched, skip the path */ 1902 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1903 skip = true; 1904 break; 1905 } 1906 } 1907 if (skip) 1908 continue; 1909 /* 1910 * Not matched against any standard path, add the path 1911 * to result. Separate consequtive paths with ':'. 1912 */ 1913 if (fcount > 0) { 1914 filtered_path[fndx] = ':'; 1915 fndx++; 1916 } 1917 fcount++; 1918 flen = strlen(hintpath->dls_name); 1919 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1920 fndx += flen; 1921 } 1922 filtered_path[fndx] = '\0'; 1923 1924 free(SLPinfo); 1925 free(hintinfo); 1926 1927 filt_ret: 1928 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1929 } 1930 1931 static void 1932 init_dag(Obj_Entry *root) 1933 { 1934 const Needed_Entry *needed; 1935 const Objlist_Entry *elm; 1936 DoneList donelist; 1937 1938 if (root->dag_inited) 1939 return; 1940 donelist_init(&donelist); 1941 1942 /* Root object belongs to own DAG. */ 1943 objlist_push_tail(&root->dldags, root); 1944 objlist_push_tail(&root->dagmembers, root); 1945 donelist_check(&donelist, root); 1946 1947 /* 1948 * Add dependencies of root object to DAG in breadth order 1949 * by exploiting the fact that each new object get added 1950 * to the tail of the dagmembers list. 1951 */ 1952 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1953 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1954 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1955 continue; 1956 objlist_push_tail(&needed->obj->dldags, root); 1957 objlist_push_tail(&root->dagmembers, needed->obj); 1958 } 1959 } 1960 root->dag_inited = true; 1961 } 1962 1963 static void 1964 init_marker(Obj_Entry *marker) 1965 { 1966 1967 bzero(marker, sizeof(*marker)); 1968 marker->marker = true; 1969 } 1970 1971 Obj_Entry * 1972 globallist_curr(const Obj_Entry *obj) 1973 { 1974 1975 for (;;) { 1976 if (obj == NULL) 1977 return (NULL); 1978 if (!obj->marker) 1979 return (__DECONST(Obj_Entry *, obj)); 1980 obj = TAILQ_PREV(obj, obj_entry_q, next); 1981 } 1982 } 1983 1984 Obj_Entry * 1985 globallist_next(const Obj_Entry *obj) 1986 { 1987 1988 for (;;) { 1989 obj = TAILQ_NEXT(obj, next); 1990 if (obj == NULL) 1991 return (NULL); 1992 if (!obj->marker) 1993 return (__DECONST(Obj_Entry *, obj)); 1994 } 1995 } 1996 1997 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1998 static void 1999 hold_object(Obj_Entry *obj) 2000 { 2001 2002 obj->holdcount++; 2003 } 2004 2005 static void 2006 unhold_object(Obj_Entry *obj) 2007 { 2008 2009 assert(obj->holdcount > 0); 2010 if (--obj->holdcount == 0 && obj->unholdfree) 2011 release_object(obj); 2012 } 2013 2014 static void 2015 process_z(Obj_Entry *root) 2016 { 2017 const Objlist_Entry *elm; 2018 Obj_Entry *obj; 2019 2020 /* 2021 * Walk over object DAG and process every dependent object 2022 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2023 * to grow their own DAG. 2024 * 2025 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2026 * symlook_global() to work. 2027 * 2028 * For DF_1_NODELETE, the DAG should have its reference upped. 2029 */ 2030 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2031 obj = elm->obj; 2032 if (obj == NULL) 2033 continue; 2034 if (obj->z_nodelete && !obj->ref_nodel) { 2035 dbg("obj %s -z nodelete", obj->path); 2036 init_dag(obj); 2037 ref_dag(obj); 2038 obj->ref_nodel = true; 2039 } 2040 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2041 dbg("obj %s -z global", obj->path); 2042 objlist_push_tail(&list_global, obj); 2043 init_dag(obj); 2044 } 2045 } 2046 } 2047 /* 2048 * Initialize the dynamic linker. The argument is the address at which 2049 * the dynamic linker has been mapped into memory. The primary task of 2050 * this function is to relocate the dynamic linker. 2051 */ 2052 static void 2053 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2054 { 2055 Obj_Entry objtmp; /* Temporary rtld object */ 2056 const Elf_Ehdr *ehdr; 2057 const Elf_Dyn *dyn_rpath; 2058 const Elf_Dyn *dyn_soname; 2059 const Elf_Dyn *dyn_runpath; 2060 2061 #ifdef RTLD_INIT_PAGESIZES_EARLY 2062 /* The page size is required by the dynamic memory allocator. */ 2063 init_pagesizes(aux_info); 2064 #endif 2065 2066 /* 2067 * Conjure up an Obj_Entry structure for the dynamic linker. 2068 * 2069 * The "path" member can't be initialized yet because string constants 2070 * cannot yet be accessed. Below we will set it correctly. 2071 */ 2072 memset(&objtmp, 0, sizeof(objtmp)); 2073 objtmp.path = NULL; 2074 objtmp.rtld = true; 2075 objtmp.mapbase = mapbase; 2076 #ifdef PIC 2077 objtmp.relocbase = mapbase; 2078 #endif 2079 2080 objtmp.dynamic = rtld_dynamic(&objtmp); 2081 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2082 assert(objtmp.needed == NULL); 2083 #if !defined(__mips__) 2084 /* MIPS has a bogus DT_TEXTREL. */ 2085 assert(!objtmp.textrel); 2086 #endif 2087 /* 2088 * Temporarily put the dynamic linker entry into the object list, so 2089 * that symbols can be found. 2090 */ 2091 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2092 2093 ehdr = (Elf_Ehdr *)mapbase; 2094 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2095 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2096 2097 /* Initialize the object list. */ 2098 TAILQ_INIT(&obj_list); 2099 2100 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2101 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2102 2103 #ifndef RTLD_INIT_PAGESIZES_EARLY 2104 /* The page size is required by the dynamic memory allocator. */ 2105 init_pagesizes(aux_info); 2106 #endif 2107 2108 if (aux_info[AT_OSRELDATE] != NULL) 2109 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2110 2111 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2112 2113 /* Replace the path with a dynamically allocated copy. */ 2114 obj_rtld.path = xstrdup(ld_path_rtld); 2115 2116 r_debug.r_brk = r_debug_state; 2117 r_debug.r_state = RT_CONSISTENT; 2118 } 2119 2120 /* 2121 * Retrieve the array of supported page sizes. The kernel provides the page 2122 * sizes in increasing order. 2123 */ 2124 static void 2125 init_pagesizes(Elf_Auxinfo **aux_info) 2126 { 2127 static size_t psa[MAXPAGESIZES]; 2128 int mib[2]; 2129 size_t len, size; 2130 2131 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2132 NULL) { 2133 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2134 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2135 } else { 2136 len = 2; 2137 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2138 size = sizeof(psa); 2139 else { 2140 /* As a fallback, retrieve the base page size. */ 2141 size = sizeof(psa[0]); 2142 if (aux_info[AT_PAGESZ] != NULL) { 2143 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2144 goto psa_filled; 2145 } else { 2146 mib[0] = CTL_HW; 2147 mib[1] = HW_PAGESIZE; 2148 len = 2; 2149 } 2150 } 2151 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2152 _rtld_error("sysctl for hw.pagesize(s) failed"); 2153 rtld_die(); 2154 } 2155 psa_filled: 2156 pagesizes = psa; 2157 } 2158 npagesizes = size / sizeof(pagesizes[0]); 2159 /* Discard any invalid entries at the end of the array. */ 2160 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2161 npagesizes--; 2162 } 2163 2164 /* 2165 * Add the init functions from a needed object list (and its recursive 2166 * needed objects) to "list". This is not used directly; it is a helper 2167 * function for initlist_add_objects(). The write lock must be held 2168 * when this function is called. 2169 */ 2170 static void 2171 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2172 { 2173 /* Recursively process the successor needed objects. */ 2174 if (needed->next != NULL) 2175 initlist_add_neededs(needed->next, list); 2176 2177 /* Process the current needed object. */ 2178 if (needed->obj != NULL) 2179 initlist_add_objects(needed->obj, needed->obj, list); 2180 } 2181 2182 /* 2183 * Scan all of the DAGs rooted in the range of objects from "obj" to 2184 * "tail" and add their init functions to "list". This recurses over 2185 * the DAGs and ensure the proper init ordering such that each object's 2186 * needed libraries are initialized before the object itself. At the 2187 * same time, this function adds the objects to the global finalization 2188 * list "list_fini" in the opposite order. The write lock must be 2189 * held when this function is called. 2190 */ 2191 static void 2192 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2193 { 2194 Obj_Entry *nobj; 2195 2196 if (obj->init_scanned || obj->init_done) 2197 return; 2198 obj->init_scanned = true; 2199 2200 /* Recursively process the successor objects. */ 2201 nobj = globallist_next(obj); 2202 if (nobj != NULL && obj != tail) 2203 initlist_add_objects(nobj, tail, list); 2204 2205 /* Recursively process the needed objects. */ 2206 if (obj->needed != NULL) 2207 initlist_add_neededs(obj->needed, list); 2208 if (obj->needed_filtees != NULL) 2209 initlist_add_neededs(obj->needed_filtees, list); 2210 if (obj->needed_aux_filtees != NULL) 2211 initlist_add_neededs(obj->needed_aux_filtees, list); 2212 2213 /* Add the object to the init list. */ 2214 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2215 obj->init_array != (Elf_Addr)NULL) 2216 objlist_push_tail(list, obj); 2217 2218 /* Add the object to the global fini list in the reverse order. */ 2219 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2220 && !obj->on_fini_list) { 2221 objlist_push_head(&list_fini, obj); 2222 obj->on_fini_list = true; 2223 } 2224 } 2225 2226 #ifndef FPTR_TARGET 2227 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2228 #endif 2229 2230 static void 2231 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2232 { 2233 Needed_Entry *needed, *needed1; 2234 2235 for (needed = n; needed != NULL; needed = needed->next) { 2236 if (needed->obj != NULL) { 2237 dlclose_locked(needed->obj, lockstate); 2238 needed->obj = NULL; 2239 } 2240 } 2241 for (needed = n; needed != NULL; needed = needed1) { 2242 needed1 = needed->next; 2243 free(needed); 2244 } 2245 } 2246 2247 static void 2248 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2249 { 2250 2251 free_needed_filtees(obj->needed_filtees, lockstate); 2252 obj->needed_filtees = NULL; 2253 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2254 obj->needed_aux_filtees = NULL; 2255 obj->filtees_loaded = false; 2256 } 2257 2258 static void 2259 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2260 RtldLockState *lockstate) 2261 { 2262 2263 for (; needed != NULL; needed = needed->next) { 2264 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2265 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2266 RTLD_LOCAL, lockstate); 2267 } 2268 } 2269 2270 static void 2271 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2272 { 2273 2274 lock_restart_for_upgrade(lockstate); 2275 if (!obj->filtees_loaded) { 2276 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2277 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2278 obj->filtees_loaded = true; 2279 } 2280 } 2281 2282 static int 2283 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2284 { 2285 Obj_Entry *obj1; 2286 2287 for (; needed != NULL; needed = needed->next) { 2288 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2289 flags & ~RTLD_LO_NOLOAD); 2290 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2291 return (-1); 2292 } 2293 return (0); 2294 } 2295 2296 /* 2297 * Given a shared object, traverse its list of needed objects, and load 2298 * each of them. Returns 0 on success. Generates an error message and 2299 * returns -1 on failure. 2300 */ 2301 static int 2302 load_needed_objects(Obj_Entry *first, int flags) 2303 { 2304 Obj_Entry *obj; 2305 2306 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2307 if (obj->marker) 2308 continue; 2309 if (process_needed(obj, obj->needed, flags) == -1) 2310 return (-1); 2311 } 2312 return (0); 2313 } 2314 2315 static int 2316 load_preload_objects(void) 2317 { 2318 char *p = ld_preload; 2319 Obj_Entry *obj; 2320 static const char delim[] = " \t:;"; 2321 2322 if (p == NULL) 2323 return 0; 2324 2325 p += strspn(p, delim); 2326 while (*p != '\0') { 2327 size_t len = strcspn(p, delim); 2328 char savech; 2329 2330 savech = p[len]; 2331 p[len] = '\0'; 2332 obj = load_object(p, -1, NULL, 0); 2333 if (obj == NULL) 2334 return -1; /* XXX - cleanup */ 2335 obj->z_interpose = true; 2336 p[len] = savech; 2337 p += len; 2338 p += strspn(p, delim); 2339 } 2340 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2341 return 0; 2342 } 2343 2344 static const char * 2345 printable_path(const char *path) 2346 { 2347 2348 return (path == NULL ? "<unknown>" : path); 2349 } 2350 2351 /* 2352 * Load a shared object into memory, if it is not already loaded. The 2353 * object may be specified by name or by user-supplied file descriptor 2354 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2355 * duplicate is. 2356 * 2357 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2358 * on failure. 2359 */ 2360 static Obj_Entry * 2361 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2362 { 2363 Obj_Entry *obj; 2364 int fd; 2365 struct stat sb; 2366 char *path; 2367 2368 fd = -1; 2369 if (name != NULL) { 2370 TAILQ_FOREACH(obj, &obj_list, next) { 2371 if (obj->marker || obj->doomed) 2372 continue; 2373 if (object_match_name(obj, name)) 2374 return (obj); 2375 } 2376 2377 path = find_library(name, refobj, &fd); 2378 if (path == NULL) 2379 return (NULL); 2380 } else 2381 path = NULL; 2382 2383 if (fd >= 0) { 2384 /* 2385 * search_library_pathfds() opens a fresh file descriptor for the 2386 * library, so there is no need to dup(). 2387 */ 2388 } else if (fd_u == -1) { 2389 /* 2390 * If we didn't find a match by pathname, or the name is not 2391 * supplied, open the file and check again by device and inode. 2392 * This avoids false mismatches caused by multiple links or ".." 2393 * in pathnames. 2394 * 2395 * To avoid a race, we open the file and use fstat() rather than 2396 * using stat(). 2397 */ 2398 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2399 _rtld_error("Cannot open \"%s\"", path); 2400 free(path); 2401 return (NULL); 2402 } 2403 } else { 2404 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2405 if (fd == -1) { 2406 _rtld_error("Cannot dup fd"); 2407 free(path); 2408 return (NULL); 2409 } 2410 } 2411 if (fstat(fd, &sb) == -1) { 2412 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2413 close(fd); 2414 free(path); 2415 return NULL; 2416 } 2417 TAILQ_FOREACH(obj, &obj_list, next) { 2418 if (obj->marker || obj->doomed) 2419 continue; 2420 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2421 break; 2422 } 2423 if (obj != NULL && name != NULL) { 2424 object_add_name(obj, name); 2425 free(path); 2426 close(fd); 2427 return obj; 2428 } 2429 if (flags & RTLD_LO_NOLOAD) { 2430 free(path); 2431 close(fd); 2432 return (NULL); 2433 } 2434 2435 /* First use of this object, so we must map it in */ 2436 obj = do_load_object(fd, name, path, &sb, flags); 2437 if (obj == NULL) 2438 free(path); 2439 close(fd); 2440 2441 return obj; 2442 } 2443 2444 static Obj_Entry * 2445 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2446 int flags) 2447 { 2448 Obj_Entry *obj; 2449 struct statfs fs; 2450 2451 /* 2452 * but first, make sure that environment variables haven't been 2453 * used to circumvent the noexec flag on a filesystem. 2454 */ 2455 if (dangerous_ld_env) { 2456 if (fstatfs(fd, &fs) != 0) { 2457 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2458 return NULL; 2459 } 2460 if (fs.f_flags & MNT_NOEXEC) { 2461 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2462 return NULL; 2463 } 2464 } 2465 dbg("loading \"%s\"", printable_path(path)); 2466 obj = map_object(fd, printable_path(path), sbp); 2467 if (obj == NULL) 2468 return NULL; 2469 2470 /* 2471 * If DT_SONAME is present in the object, digest_dynamic2 already 2472 * added it to the object names. 2473 */ 2474 if (name != NULL) 2475 object_add_name(obj, name); 2476 obj->path = path; 2477 digest_dynamic(obj, 0); 2478 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2479 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2480 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2481 RTLD_LO_DLOPEN) { 2482 dbg("refusing to load non-loadable \"%s\"", obj->path); 2483 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2484 munmap(obj->mapbase, obj->mapsize); 2485 obj_free(obj); 2486 return (NULL); 2487 } 2488 2489 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2490 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2491 obj_count++; 2492 obj_loads++; 2493 linkmap_add(obj); /* for GDB & dlinfo() */ 2494 max_stack_flags |= obj->stack_flags; 2495 2496 dbg(" %p .. %p: %s", obj->mapbase, 2497 obj->mapbase + obj->mapsize - 1, obj->path); 2498 if (obj->textrel) 2499 dbg(" WARNING: %s has impure text", obj->path); 2500 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2501 obj->path); 2502 2503 return obj; 2504 } 2505 2506 static Obj_Entry * 2507 obj_from_addr(const void *addr) 2508 { 2509 Obj_Entry *obj; 2510 2511 TAILQ_FOREACH(obj, &obj_list, next) { 2512 if (obj->marker) 2513 continue; 2514 if (addr < (void *) obj->mapbase) 2515 continue; 2516 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2517 return obj; 2518 } 2519 return NULL; 2520 } 2521 2522 static void 2523 preinit_main(void) 2524 { 2525 Elf_Addr *preinit_addr; 2526 int index; 2527 2528 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2529 if (preinit_addr == NULL) 2530 return; 2531 2532 for (index = 0; index < obj_main->preinit_array_num; index++) { 2533 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2534 dbg("calling preinit function for %s at %p", obj_main->path, 2535 (void *)preinit_addr[index]); 2536 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2537 0, 0, obj_main->path); 2538 call_init_pointer(obj_main, preinit_addr[index]); 2539 } 2540 } 2541 } 2542 2543 /* 2544 * Call the finalization functions for each of the objects in "list" 2545 * belonging to the DAG of "root" and referenced once. If NULL "root" 2546 * is specified, every finalization function will be called regardless 2547 * of the reference count and the list elements won't be freed. All of 2548 * the objects are expected to have non-NULL fini functions. 2549 */ 2550 static void 2551 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2552 { 2553 Objlist_Entry *elm; 2554 char *saved_msg; 2555 Elf_Addr *fini_addr; 2556 int index; 2557 2558 assert(root == NULL || root->refcount == 1); 2559 2560 if (root != NULL) 2561 root->doomed = true; 2562 2563 /* 2564 * Preserve the current error message since a fini function might 2565 * call into the dynamic linker and overwrite it. 2566 */ 2567 saved_msg = errmsg_save(); 2568 do { 2569 STAILQ_FOREACH(elm, list, link) { 2570 if (root != NULL && (elm->obj->refcount != 1 || 2571 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2572 continue; 2573 /* Remove object from fini list to prevent recursive invocation. */ 2574 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2575 /* Ensure that new references cannot be acquired. */ 2576 elm->obj->doomed = true; 2577 2578 hold_object(elm->obj); 2579 lock_release(rtld_bind_lock, lockstate); 2580 /* 2581 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2582 * When this happens, DT_FINI_ARRAY is processed first. 2583 */ 2584 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2585 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2586 for (index = elm->obj->fini_array_num - 1; index >= 0; 2587 index--) { 2588 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2589 dbg("calling fini function for %s at %p", 2590 elm->obj->path, (void *)fini_addr[index]); 2591 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2592 (void *)fini_addr[index], 0, 0, elm->obj->path); 2593 call_initfini_pointer(elm->obj, fini_addr[index]); 2594 } 2595 } 2596 } 2597 if (elm->obj->fini != (Elf_Addr)NULL) { 2598 dbg("calling fini function for %s at %p", elm->obj->path, 2599 (void *)elm->obj->fini); 2600 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2601 0, 0, elm->obj->path); 2602 call_initfini_pointer(elm->obj, elm->obj->fini); 2603 } 2604 wlock_acquire(rtld_bind_lock, lockstate); 2605 unhold_object(elm->obj); 2606 /* No need to free anything if process is going down. */ 2607 if (root != NULL) 2608 free(elm); 2609 /* 2610 * We must restart the list traversal after every fini call 2611 * because a dlclose() call from the fini function or from 2612 * another thread might have modified the reference counts. 2613 */ 2614 break; 2615 } 2616 } while (elm != NULL); 2617 errmsg_restore(saved_msg); 2618 } 2619 2620 /* 2621 * Call the initialization functions for each of the objects in 2622 * "list". All of the objects are expected to have non-NULL init 2623 * functions. 2624 */ 2625 static void 2626 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2627 { 2628 Objlist_Entry *elm; 2629 Obj_Entry *obj; 2630 char *saved_msg; 2631 Elf_Addr *init_addr; 2632 int index; 2633 2634 /* 2635 * Clean init_scanned flag so that objects can be rechecked and 2636 * possibly initialized earlier if any of vectors called below 2637 * cause the change by using dlopen. 2638 */ 2639 TAILQ_FOREACH(obj, &obj_list, next) { 2640 if (obj->marker) 2641 continue; 2642 obj->init_scanned = false; 2643 } 2644 2645 /* 2646 * Preserve the current error message since an init function might 2647 * call into the dynamic linker and overwrite it. 2648 */ 2649 saved_msg = errmsg_save(); 2650 STAILQ_FOREACH(elm, list, link) { 2651 if (elm->obj->init_done) /* Initialized early. */ 2652 continue; 2653 /* 2654 * Race: other thread might try to use this object before current 2655 * one completes the initialization. Not much can be done here 2656 * without better locking. 2657 */ 2658 elm->obj->init_done = true; 2659 hold_object(elm->obj); 2660 lock_release(rtld_bind_lock, lockstate); 2661 2662 /* 2663 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2664 * When this happens, DT_INIT is processed first. 2665 */ 2666 if (elm->obj->init != (Elf_Addr)NULL) { 2667 dbg("calling init function for %s at %p", elm->obj->path, 2668 (void *)elm->obj->init); 2669 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2670 0, 0, elm->obj->path); 2671 call_initfini_pointer(elm->obj, elm->obj->init); 2672 } 2673 init_addr = (Elf_Addr *)elm->obj->init_array; 2674 if (init_addr != NULL) { 2675 for (index = 0; index < elm->obj->init_array_num; index++) { 2676 if (init_addr[index] != 0 && init_addr[index] != 1) { 2677 dbg("calling init function for %s at %p", elm->obj->path, 2678 (void *)init_addr[index]); 2679 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2680 (void *)init_addr[index], 0, 0, elm->obj->path); 2681 call_init_pointer(elm->obj, init_addr[index]); 2682 } 2683 } 2684 } 2685 wlock_acquire(rtld_bind_lock, lockstate); 2686 unhold_object(elm->obj); 2687 } 2688 errmsg_restore(saved_msg); 2689 } 2690 2691 static void 2692 objlist_clear(Objlist *list) 2693 { 2694 Objlist_Entry *elm; 2695 2696 while (!STAILQ_EMPTY(list)) { 2697 elm = STAILQ_FIRST(list); 2698 STAILQ_REMOVE_HEAD(list, link); 2699 free(elm); 2700 } 2701 } 2702 2703 static Objlist_Entry * 2704 objlist_find(Objlist *list, const Obj_Entry *obj) 2705 { 2706 Objlist_Entry *elm; 2707 2708 STAILQ_FOREACH(elm, list, link) 2709 if (elm->obj == obj) 2710 return elm; 2711 return NULL; 2712 } 2713 2714 static void 2715 objlist_init(Objlist *list) 2716 { 2717 STAILQ_INIT(list); 2718 } 2719 2720 static void 2721 objlist_push_head(Objlist *list, Obj_Entry *obj) 2722 { 2723 Objlist_Entry *elm; 2724 2725 elm = NEW(Objlist_Entry); 2726 elm->obj = obj; 2727 STAILQ_INSERT_HEAD(list, elm, link); 2728 } 2729 2730 static void 2731 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2732 { 2733 Objlist_Entry *elm; 2734 2735 elm = NEW(Objlist_Entry); 2736 elm->obj = obj; 2737 STAILQ_INSERT_TAIL(list, elm, link); 2738 } 2739 2740 static void 2741 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2742 { 2743 Objlist_Entry *elm, *listelm; 2744 2745 STAILQ_FOREACH(listelm, list, link) { 2746 if (listelm->obj == listobj) 2747 break; 2748 } 2749 elm = NEW(Objlist_Entry); 2750 elm->obj = obj; 2751 if (listelm != NULL) 2752 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2753 else 2754 STAILQ_INSERT_TAIL(list, elm, link); 2755 } 2756 2757 static void 2758 objlist_remove(Objlist *list, Obj_Entry *obj) 2759 { 2760 Objlist_Entry *elm; 2761 2762 if ((elm = objlist_find(list, obj)) != NULL) { 2763 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2764 free(elm); 2765 } 2766 } 2767 2768 /* 2769 * Relocate dag rooted in the specified object. 2770 * Returns 0 on success, or -1 on failure. 2771 */ 2772 2773 static int 2774 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2775 int flags, RtldLockState *lockstate) 2776 { 2777 Objlist_Entry *elm; 2778 int error; 2779 2780 error = 0; 2781 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2782 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2783 lockstate); 2784 if (error == -1) 2785 break; 2786 } 2787 return (error); 2788 } 2789 2790 /* 2791 * Prepare for, or clean after, relocating an object marked with 2792 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2793 * segments are remapped read-write. After relocations are done, the 2794 * segment's permissions are returned back to the modes specified in 2795 * the phdrs. If any relocation happened, or always for wired 2796 * program, COW is triggered. 2797 */ 2798 static int 2799 reloc_textrel_prot(Obj_Entry *obj, bool before) 2800 { 2801 const Elf_Phdr *ph; 2802 void *base; 2803 size_t l, sz; 2804 int prot; 2805 2806 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2807 l--, ph++) { 2808 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2809 continue; 2810 base = obj->relocbase + trunc_page(ph->p_vaddr); 2811 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2812 trunc_page(ph->p_vaddr); 2813 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2814 if (mprotect(base, sz, prot) == -1) { 2815 _rtld_error("%s: Cannot write-%sable text segment: %s", 2816 obj->path, before ? "en" : "dis", 2817 rtld_strerror(errno)); 2818 return (-1); 2819 } 2820 } 2821 return (0); 2822 } 2823 2824 /* 2825 * Relocate single object. 2826 * Returns 0 on success, or -1 on failure. 2827 */ 2828 static int 2829 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2830 int flags, RtldLockState *lockstate) 2831 { 2832 2833 if (obj->relocated) 2834 return (0); 2835 obj->relocated = true; 2836 if (obj != rtldobj) 2837 dbg("relocating \"%s\"", obj->path); 2838 2839 if (obj->symtab == NULL || obj->strtab == NULL || 2840 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2841 _rtld_error("%s: Shared object has no run-time symbol table", 2842 obj->path); 2843 return (-1); 2844 } 2845 2846 /* There are relocations to the write-protected text segment. */ 2847 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2848 return (-1); 2849 2850 /* Process the non-PLT non-IFUNC relocations. */ 2851 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2852 return (-1); 2853 2854 /* Re-protected the text segment. */ 2855 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2856 return (-1); 2857 2858 /* Set the special PLT or GOT entries. */ 2859 init_pltgot(obj); 2860 2861 /* Process the PLT relocations. */ 2862 if (reloc_plt(obj) == -1) 2863 return (-1); 2864 /* Relocate the jump slots if we are doing immediate binding. */ 2865 if (obj->bind_now || bind_now) 2866 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2867 return (-1); 2868 2869 /* 2870 * Process the non-PLT IFUNC relocations. The relocations are 2871 * processed in two phases, because IFUNC resolvers may 2872 * reference other symbols, which must be readily processed 2873 * before resolvers are called. 2874 */ 2875 if (obj->non_plt_gnu_ifunc && 2876 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2877 return (-1); 2878 2879 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2880 return (-1); 2881 2882 /* 2883 * Set up the magic number and version in the Obj_Entry. These 2884 * were checked in the crt1.o from the original ElfKit, so we 2885 * set them for backward compatibility. 2886 */ 2887 obj->magic = RTLD_MAGIC; 2888 obj->version = RTLD_VERSION; 2889 2890 return (0); 2891 } 2892 2893 /* 2894 * Relocate newly-loaded shared objects. The argument is a pointer to 2895 * the Obj_Entry for the first such object. All objects from the first 2896 * to the end of the list of objects are relocated. Returns 0 on success, 2897 * or -1 on failure. 2898 */ 2899 static int 2900 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2901 int flags, RtldLockState *lockstate) 2902 { 2903 Obj_Entry *obj; 2904 int error; 2905 2906 for (error = 0, obj = first; obj != NULL; 2907 obj = TAILQ_NEXT(obj, next)) { 2908 if (obj->marker) 2909 continue; 2910 error = relocate_object(obj, bind_now, rtldobj, flags, 2911 lockstate); 2912 if (error == -1) 2913 break; 2914 } 2915 return (error); 2916 } 2917 2918 /* 2919 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2920 * referencing STT_GNU_IFUNC symbols is postponed till the other 2921 * relocations are done. The indirect functions specified as 2922 * ifunc are allowed to call other symbols, so we need to have 2923 * objects relocated before asking for resolution from indirects. 2924 * 2925 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2926 * instead of the usual lazy handling of PLT slots. It is 2927 * consistent with how GNU does it. 2928 */ 2929 static int 2930 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2931 RtldLockState *lockstate) 2932 { 2933 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2934 return (-1); 2935 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2936 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2937 return (-1); 2938 return (0); 2939 } 2940 2941 static int 2942 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2943 RtldLockState *lockstate) 2944 { 2945 Obj_Entry *obj; 2946 2947 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2948 if (obj->marker) 2949 continue; 2950 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2951 return (-1); 2952 } 2953 return (0); 2954 } 2955 2956 static int 2957 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2958 RtldLockState *lockstate) 2959 { 2960 Objlist_Entry *elm; 2961 2962 STAILQ_FOREACH(elm, list, link) { 2963 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2964 lockstate) == -1) 2965 return (-1); 2966 } 2967 return (0); 2968 } 2969 2970 /* 2971 * Cleanup procedure. It will be called (by the atexit mechanism) just 2972 * before the process exits. 2973 */ 2974 static void 2975 rtld_exit(void) 2976 { 2977 RtldLockState lockstate; 2978 2979 wlock_acquire(rtld_bind_lock, &lockstate); 2980 dbg("rtld_exit()"); 2981 objlist_call_fini(&list_fini, NULL, &lockstate); 2982 /* No need to remove the items from the list, since we are exiting. */ 2983 if (!libmap_disable) 2984 lm_fini(); 2985 lock_release(rtld_bind_lock, &lockstate); 2986 } 2987 2988 /* 2989 * Iterate over a search path, translate each element, and invoke the 2990 * callback on the result. 2991 */ 2992 static void * 2993 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2994 { 2995 const char *trans; 2996 if (path == NULL) 2997 return (NULL); 2998 2999 path += strspn(path, ":;"); 3000 while (*path != '\0') { 3001 size_t len; 3002 char *res; 3003 3004 len = strcspn(path, ":;"); 3005 trans = lm_findn(NULL, path, len); 3006 if (trans) 3007 res = callback(trans, strlen(trans), arg); 3008 else 3009 res = callback(path, len, arg); 3010 3011 if (res != NULL) 3012 return (res); 3013 3014 path += len; 3015 path += strspn(path, ":;"); 3016 } 3017 3018 return (NULL); 3019 } 3020 3021 struct try_library_args { 3022 const char *name; 3023 size_t namelen; 3024 char *buffer; 3025 size_t buflen; 3026 }; 3027 3028 static void * 3029 try_library_path(const char *dir, size_t dirlen, void *param) 3030 { 3031 struct try_library_args *arg; 3032 3033 arg = param; 3034 if (*dir == '/' || trust) { 3035 char *pathname; 3036 3037 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3038 return (NULL); 3039 3040 pathname = arg->buffer; 3041 strncpy(pathname, dir, dirlen); 3042 pathname[dirlen] = '/'; 3043 strcpy(pathname + dirlen + 1, arg->name); 3044 3045 dbg(" Trying \"%s\"", pathname); 3046 if (access(pathname, F_OK) == 0) { /* We found it */ 3047 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3048 strcpy(pathname, arg->buffer); 3049 return (pathname); 3050 } 3051 } 3052 return (NULL); 3053 } 3054 3055 static char * 3056 search_library_path(const char *name, const char *path) 3057 { 3058 char *p; 3059 struct try_library_args arg; 3060 3061 if (path == NULL) 3062 return NULL; 3063 3064 arg.name = name; 3065 arg.namelen = strlen(name); 3066 arg.buffer = xmalloc(PATH_MAX); 3067 arg.buflen = PATH_MAX; 3068 3069 p = path_enumerate(path, try_library_path, &arg); 3070 3071 free(arg.buffer); 3072 3073 return (p); 3074 } 3075 3076 3077 /* 3078 * Finds the library with the given name using the directory descriptors 3079 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3080 * 3081 * Returns a freshly-opened close-on-exec file descriptor for the library, 3082 * or -1 if the library cannot be found. 3083 */ 3084 static char * 3085 search_library_pathfds(const char *name, const char *path, int *fdp) 3086 { 3087 char *envcopy, *fdstr, *found, *last_token; 3088 size_t len; 3089 int dirfd, fd; 3090 3091 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3092 3093 /* Don't load from user-specified libdirs into setuid binaries. */ 3094 if (!trust) 3095 return (NULL); 3096 3097 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3098 if (path == NULL) 3099 return (NULL); 3100 3101 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3102 if (name[0] == '/') { 3103 dbg("Absolute path (%s) passed to %s", name, __func__); 3104 return (NULL); 3105 } 3106 3107 /* 3108 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3109 * copy of the path, as strtok_r rewrites separator tokens 3110 * with '\0'. 3111 */ 3112 found = NULL; 3113 envcopy = xstrdup(path); 3114 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3115 fdstr = strtok_r(NULL, ":", &last_token)) { 3116 dirfd = parse_integer(fdstr); 3117 if (dirfd < 0) { 3118 _rtld_error("failed to parse directory FD: '%s'", 3119 fdstr); 3120 break; 3121 } 3122 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3123 if (fd >= 0) { 3124 *fdp = fd; 3125 len = strlen(fdstr) + strlen(name) + 3; 3126 found = xmalloc(len); 3127 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3128 _rtld_error("error generating '%d/%s'", 3129 dirfd, name); 3130 rtld_die(); 3131 } 3132 dbg("open('%s') => %d", found, fd); 3133 break; 3134 } 3135 } 3136 free(envcopy); 3137 3138 return (found); 3139 } 3140 3141 3142 int 3143 dlclose(void *handle) 3144 { 3145 RtldLockState lockstate; 3146 int error; 3147 3148 wlock_acquire(rtld_bind_lock, &lockstate); 3149 error = dlclose_locked(handle, &lockstate); 3150 lock_release(rtld_bind_lock, &lockstate); 3151 return (error); 3152 } 3153 3154 static int 3155 dlclose_locked(void *handle, RtldLockState *lockstate) 3156 { 3157 Obj_Entry *root; 3158 3159 root = dlcheck(handle); 3160 if (root == NULL) 3161 return -1; 3162 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3163 root->path); 3164 3165 /* Unreference the object and its dependencies. */ 3166 root->dl_refcount--; 3167 3168 if (root->refcount == 1) { 3169 /* 3170 * The object will be no longer referenced, so we must unload it. 3171 * First, call the fini functions. 3172 */ 3173 objlist_call_fini(&list_fini, root, lockstate); 3174 3175 unref_dag(root); 3176 3177 /* Finish cleaning up the newly-unreferenced objects. */ 3178 GDB_STATE(RT_DELETE,&root->linkmap); 3179 unload_object(root, lockstate); 3180 GDB_STATE(RT_CONSISTENT,NULL); 3181 } else 3182 unref_dag(root); 3183 3184 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3185 return 0; 3186 } 3187 3188 char * 3189 dlerror(void) 3190 { 3191 char *msg = error_message; 3192 error_message = NULL; 3193 return msg; 3194 } 3195 3196 /* 3197 * This function is deprecated and has no effect. 3198 */ 3199 void 3200 dllockinit(void *context, 3201 void *(*lock_create)(void *context), 3202 void (*rlock_acquire)(void *lock), 3203 void (*wlock_acquire)(void *lock), 3204 void (*lock_release)(void *lock), 3205 void (*lock_destroy)(void *lock), 3206 void (*context_destroy)(void *context)) 3207 { 3208 static void *cur_context; 3209 static void (*cur_context_destroy)(void *); 3210 3211 /* Just destroy the context from the previous call, if necessary. */ 3212 if (cur_context_destroy != NULL) 3213 cur_context_destroy(cur_context); 3214 cur_context = context; 3215 cur_context_destroy = context_destroy; 3216 } 3217 3218 void * 3219 dlopen(const char *name, int mode) 3220 { 3221 3222 return (rtld_dlopen(name, -1, mode)); 3223 } 3224 3225 void * 3226 fdlopen(int fd, int mode) 3227 { 3228 3229 return (rtld_dlopen(NULL, fd, mode)); 3230 } 3231 3232 static void * 3233 rtld_dlopen(const char *name, int fd, int mode) 3234 { 3235 RtldLockState lockstate; 3236 int lo_flags; 3237 3238 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3239 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3240 if (ld_tracing != NULL) { 3241 rlock_acquire(rtld_bind_lock, &lockstate); 3242 if (sigsetjmp(lockstate.env, 0) != 0) 3243 lock_upgrade(rtld_bind_lock, &lockstate); 3244 environ = (char **)*get_program_var_addr("environ", &lockstate); 3245 lock_release(rtld_bind_lock, &lockstate); 3246 } 3247 lo_flags = RTLD_LO_DLOPEN; 3248 if (mode & RTLD_NODELETE) 3249 lo_flags |= RTLD_LO_NODELETE; 3250 if (mode & RTLD_NOLOAD) 3251 lo_flags |= RTLD_LO_NOLOAD; 3252 if (ld_tracing != NULL) 3253 lo_flags |= RTLD_LO_TRACE; 3254 3255 return (dlopen_object(name, fd, obj_main, lo_flags, 3256 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3257 } 3258 3259 static void 3260 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3261 { 3262 3263 obj->dl_refcount--; 3264 unref_dag(obj); 3265 if (obj->refcount == 0) 3266 unload_object(obj, lockstate); 3267 } 3268 3269 static Obj_Entry * 3270 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3271 int mode, RtldLockState *lockstate) 3272 { 3273 Obj_Entry *old_obj_tail; 3274 Obj_Entry *obj; 3275 Objlist initlist; 3276 RtldLockState mlockstate; 3277 int result; 3278 3279 objlist_init(&initlist); 3280 3281 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3282 wlock_acquire(rtld_bind_lock, &mlockstate); 3283 lockstate = &mlockstate; 3284 } 3285 GDB_STATE(RT_ADD,NULL); 3286 3287 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3288 obj = NULL; 3289 if (name == NULL && fd == -1) { 3290 obj = obj_main; 3291 obj->refcount++; 3292 } else { 3293 obj = load_object(name, fd, refobj, lo_flags); 3294 } 3295 3296 if (obj) { 3297 obj->dl_refcount++; 3298 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3299 objlist_push_tail(&list_global, obj); 3300 if (globallist_next(old_obj_tail) != NULL) { 3301 /* We loaded something new. */ 3302 assert(globallist_next(old_obj_tail) == obj); 3303 result = load_needed_objects(obj, 3304 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3305 init_dag(obj); 3306 ref_dag(obj); 3307 if (result != -1) 3308 result = rtld_verify_versions(&obj->dagmembers); 3309 if (result != -1 && ld_tracing) 3310 goto trace; 3311 if (result == -1 || relocate_object_dag(obj, 3312 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3313 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3314 lockstate) == -1) { 3315 dlopen_cleanup(obj, lockstate); 3316 obj = NULL; 3317 } else if (lo_flags & RTLD_LO_EARLY) { 3318 /* 3319 * Do not call the init functions for early loaded 3320 * filtees. The image is still not initialized enough 3321 * for them to work. 3322 * 3323 * Our object is found by the global object list and 3324 * will be ordered among all init calls done right 3325 * before transferring control to main. 3326 */ 3327 } else { 3328 /* Make list of init functions to call. */ 3329 initlist_add_objects(obj, obj, &initlist); 3330 } 3331 /* 3332 * Process all no_delete or global objects here, given 3333 * them own DAGs to prevent their dependencies from being 3334 * unloaded. This has to be done after we have loaded all 3335 * of the dependencies, so that we do not miss any. 3336 */ 3337 if (obj != NULL) 3338 process_z(obj); 3339 } else { 3340 /* 3341 * Bump the reference counts for objects on this DAG. If 3342 * this is the first dlopen() call for the object that was 3343 * already loaded as a dependency, initialize the dag 3344 * starting at it. 3345 */ 3346 init_dag(obj); 3347 ref_dag(obj); 3348 3349 if ((lo_flags & RTLD_LO_TRACE) != 0) 3350 goto trace; 3351 } 3352 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3353 obj->z_nodelete) && !obj->ref_nodel) { 3354 dbg("obj %s nodelete", obj->path); 3355 ref_dag(obj); 3356 obj->z_nodelete = obj->ref_nodel = true; 3357 } 3358 } 3359 3360 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3361 name); 3362 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3363 3364 if (!(lo_flags & RTLD_LO_EARLY)) { 3365 map_stacks_exec(lockstate); 3366 } 3367 3368 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3369 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3370 lockstate) == -1) { 3371 objlist_clear(&initlist); 3372 dlopen_cleanup(obj, lockstate); 3373 if (lockstate == &mlockstate) 3374 lock_release(rtld_bind_lock, lockstate); 3375 return (NULL); 3376 } 3377 3378 if (!(lo_flags & RTLD_LO_EARLY)) { 3379 /* Call the init functions. */ 3380 objlist_call_init(&initlist, lockstate); 3381 } 3382 objlist_clear(&initlist); 3383 if (lockstate == &mlockstate) 3384 lock_release(rtld_bind_lock, lockstate); 3385 return obj; 3386 trace: 3387 trace_loaded_objects(obj); 3388 if (lockstate == &mlockstate) 3389 lock_release(rtld_bind_lock, lockstate); 3390 exit(0); 3391 } 3392 3393 static void * 3394 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3395 int flags) 3396 { 3397 DoneList donelist; 3398 const Obj_Entry *obj, *defobj; 3399 const Elf_Sym *def; 3400 SymLook req; 3401 RtldLockState lockstate; 3402 tls_index ti; 3403 void *sym; 3404 int res; 3405 3406 def = NULL; 3407 defobj = NULL; 3408 symlook_init(&req, name); 3409 req.ventry = ve; 3410 req.flags = flags | SYMLOOK_IN_PLT; 3411 req.lockstate = &lockstate; 3412 3413 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3414 rlock_acquire(rtld_bind_lock, &lockstate); 3415 if (sigsetjmp(lockstate.env, 0) != 0) 3416 lock_upgrade(rtld_bind_lock, &lockstate); 3417 if (handle == NULL || handle == RTLD_NEXT || 3418 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3419 3420 if ((obj = obj_from_addr(retaddr)) == NULL) { 3421 _rtld_error("Cannot determine caller's shared object"); 3422 lock_release(rtld_bind_lock, &lockstate); 3423 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3424 return NULL; 3425 } 3426 if (handle == NULL) { /* Just the caller's shared object. */ 3427 res = symlook_obj(&req, obj); 3428 if (res == 0) { 3429 def = req.sym_out; 3430 defobj = req.defobj_out; 3431 } 3432 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3433 handle == RTLD_SELF) { /* ... caller included */ 3434 if (handle == RTLD_NEXT) 3435 obj = globallist_next(obj); 3436 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3437 if (obj->marker) 3438 continue; 3439 res = symlook_obj(&req, obj); 3440 if (res == 0) { 3441 if (def == NULL || 3442 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3443 def = req.sym_out; 3444 defobj = req.defobj_out; 3445 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3446 break; 3447 } 3448 } 3449 } 3450 /* 3451 * Search the dynamic linker itself, and possibly resolve the 3452 * symbol from there. This is how the application links to 3453 * dynamic linker services such as dlopen. 3454 */ 3455 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3456 res = symlook_obj(&req, &obj_rtld); 3457 if (res == 0) { 3458 def = req.sym_out; 3459 defobj = req.defobj_out; 3460 } 3461 } 3462 } else { 3463 assert(handle == RTLD_DEFAULT); 3464 res = symlook_default(&req, obj); 3465 if (res == 0) { 3466 defobj = req.defobj_out; 3467 def = req.sym_out; 3468 } 3469 } 3470 } else { 3471 if ((obj = dlcheck(handle)) == NULL) { 3472 lock_release(rtld_bind_lock, &lockstate); 3473 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3474 return NULL; 3475 } 3476 3477 donelist_init(&donelist); 3478 if (obj->mainprog) { 3479 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3480 res = symlook_global(&req, &donelist); 3481 if (res == 0) { 3482 def = req.sym_out; 3483 defobj = req.defobj_out; 3484 } 3485 /* 3486 * Search the dynamic linker itself, and possibly resolve the 3487 * symbol from there. This is how the application links to 3488 * dynamic linker services such as dlopen. 3489 */ 3490 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3491 res = symlook_obj(&req, &obj_rtld); 3492 if (res == 0) { 3493 def = req.sym_out; 3494 defobj = req.defobj_out; 3495 } 3496 } 3497 } 3498 else { 3499 /* Search the whole DAG rooted at the given object. */ 3500 res = symlook_list(&req, &obj->dagmembers, &donelist); 3501 if (res == 0) { 3502 def = req.sym_out; 3503 defobj = req.defobj_out; 3504 } 3505 } 3506 } 3507 3508 if (def != NULL) { 3509 lock_release(rtld_bind_lock, &lockstate); 3510 3511 /* 3512 * The value required by the caller is derived from the value 3513 * of the symbol. this is simply the relocated value of the 3514 * symbol. 3515 */ 3516 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3517 sym = make_function_pointer(def, defobj); 3518 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3519 sym = rtld_resolve_ifunc(defobj, def); 3520 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3521 ti.ti_module = defobj->tlsindex; 3522 ti.ti_offset = def->st_value; 3523 sym = __tls_get_addr(&ti); 3524 } else 3525 sym = defobj->relocbase + def->st_value; 3526 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3527 return (sym); 3528 } 3529 3530 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3531 ve != NULL ? ve->name : ""); 3532 lock_release(rtld_bind_lock, &lockstate); 3533 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3534 return NULL; 3535 } 3536 3537 void * 3538 dlsym(void *handle, const char *name) 3539 { 3540 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3541 SYMLOOK_DLSYM); 3542 } 3543 3544 dlfunc_t 3545 dlfunc(void *handle, const char *name) 3546 { 3547 union { 3548 void *d; 3549 dlfunc_t f; 3550 } rv; 3551 3552 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3553 SYMLOOK_DLSYM); 3554 return (rv.f); 3555 } 3556 3557 void * 3558 dlvsym(void *handle, const char *name, const char *version) 3559 { 3560 Ver_Entry ventry; 3561 3562 ventry.name = version; 3563 ventry.file = NULL; 3564 ventry.hash = elf_hash(version); 3565 ventry.flags= 0; 3566 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3567 SYMLOOK_DLSYM); 3568 } 3569 3570 int 3571 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3572 { 3573 const Obj_Entry *obj; 3574 RtldLockState lockstate; 3575 3576 rlock_acquire(rtld_bind_lock, &lockstate); 3577 obj = obj_from_addr(addr); 3578 if (obj == NULL) { 3579 _rtld_error("No shared object contains address"); 3580 lock_release(rtld_bind_lock, &lockstate); 3581 return (0); 3582 } 3583 rtld_fill_dl_phdr_info(obj, phdr_info); 3584 lock_release(rtld_bind_lock, &lockstate); 3585 return (1); 3586 } 3587 3588 int 3589 dladdr(const void *addr, Dl_info *info) 3590 { 3591 const Obj_Entry *obj; 3592 const Elf_Sym *def; 3593 void *symbol_addr; 3594 unsigned long symoffset; 3595 RtldLockState lockstate; 3596 3597 rlock_acquire(rtld_bind_lock, &lockstate); 3598 obj = obj_from_addr(addr); 3599 if (obj == NULL) { 3600 _rtld_error("No shared object contains address"); 3601 lock_release(rtld_bind_lock, &lockstate); 3602 return 0; 3603 } 3604 info->dli_fname = obj->path; 3605 info->dli_fbase = obj->mapbase; 3606 info->dli_saddr = (void *)0; 3607 info->dli_sname = NULL; 3608 3609 /* 3610 * Walk the symbol list looking for the symbol whose address is 3611 * closest to the address sent in. 3612 */ 3613 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3614 def = obj->symtab + symoffset; 3615 3616 /* 3617 * For skip the symbol if st_shndx is either SHN_UNDEF or 3618 * SHN_COMMON. 3619 */ 3620 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3621 continue; 3622 3623 /* 3624 * If the symbol is greater than the specified address, or if it 3625 * is further away from addr than the current nearest symbol, 3626 * then reject it. 3627 */ 3628 symbol_addr = obj->relocbase + def->st_value; 3629 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3630 continue; 3631 3632 /* Update our idea of the nearest symbol. */ 3633 info->dli_sname = obj->strtab + def->st_name; 3634 info->dli_saddr = symbol_addr; 3635 3636 /* Exact match? */ 3637 if (info->dli_saddr == addr) 3638 break; 3639 } 3640 lock_release(rtld_bind_lock, &lockstate); 3641 return 1; 3642 } 3643 3644 int 3645 dlinfo(void *handle, int request, void *p) 3646 { 3647 const Obj_Entry *obj; 3648 RtldLockState lockstate; 3649 int error; 3650 3651 rlock_acquire(rtld_bind_lock, &lockstate); 3652 3653 if (handle == NULL || handle == RTLD_SELF) { 3654 void *retaddr; 3655 3656 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3657 if ((obj = obj_from_addr(retaddr)) == NULL) 3658 _rtld_error("Cannot determine caller's shared object"); 3659 } else 3660 obj = dlcheck(handle); 3661 3662 if (obj == NULL) { 3663 lock_release(rtld_bind_lock, &lockstate); 3664 return (-1); 3665 } 3666 3667 error = 0; 3668 switch (request) { 3669 case RTLD_DI_LINKMAP: 3670 *((struct link_map const **)p) = &obj->linkmap; 3671 break; 3672 case RTLD_DI_ORIGIN: 3673 error = rtld_dirname(obj->path, p); 3674 break; 3675 3676 case RTLD_DI_SERINFOSIZE: 3677 case RTLD_DI_SERINFO: 3678 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3679 break; 3680 3681 default: 3682 _rtld_error("Invalid request %d passed to dlinfo()", request); 3683 error = -1; 3684 } 3685 3686 lock_release(rtld_bind_lock, &lockstate); 3687 3688 return (error); 3689 } 3690 3691 static void 3692 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3693 { 3694 3695 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3696 phdr_info->dlpi_name = obj->path; 3697 phdr_info->dlpi_phdr = obj->phdr; 3698 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3699 phdr_info->dlpi_tls_modid = obj->tlsindex; 3700 phdr_info->dlpi_tls_data = obj->tlsinit; 3701 phdr_info->dlpi_adds = obj_loads; 3702 phdr_info->dlpi_subs = obj_loads - obj_count; 3703 } 3704 3705 int 3706 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3707 { 3708 struct dl_phdr_info phdr_info; 3709 Obj_Entry *obj, marker; 3710 RtldLockState bind_lockstate, phdr_lockstate; 3711 int error; 3712 3713 init_marker(&marker); 3714 error = 0; 3715 3716 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3717 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3718 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3719 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3720 rtld_fill_dl_phdr_info(obj, &phdr_info); 3721 hold_object(obj); 3722 lock_release(rtld_bind_lock, &bind_lockstate); 3723 3724 error = callback(&phdr_info, sizeof phdr_info, param); 3725 3726 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3727 unhold_object(obj); 3728 obj = globallist_next(&marker); 3729 TAILQ_REMOVE(&obj_list, &marker, next); 3730 if (error != 0) { 3731 lock_release(rtld_bind_lock, &bind_lockstate); 3732 lock_release(rtld_phdr_lock, &phdr_lockstate); 3733 return (error); 3734 } 3735 } 3736 3737 if (error == 0) { 3738 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3739 lock_release(rtld_bind_lock, &bind_lockstate); 3740 error = callback(&phdr_info, sizeof(phdr_info), param); 3741 } 3742 lock_release(rtld_phdr_lock, &phdr_lockstate); 3743 return (error); 3744 } 3745 3746 static void * 3747 fill_search_info(const char *dir, size_t dirlen, void *param) 3748 { 3749 struct fill_search_info_args *arg; 3750 3751 arg = param; 3752 3753 if (arg->request == RTLD_DI_SERINFOSIZE) { 3754 arg->serinfo->dls_cnt ++; 3755 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3756 } else { 3757 struct dl_serpath *s_entry; 3758 3759 s_entry = arg->serpath; 3760 s_entry->dls_name = arg->strspace; 3761 s_entry->dls_flags = arg->flags; 3762 3763 strncpy(arg->strspace, dir, dirlen); 3764 arg->strspace[dirlen] = '\0'; 3765 3766 arg->strspace += dirlen + 1; 3767 arg->serpath++; 3768 } 3769 3770 return (NULL); 3771 } 3772 3773 static int 3774 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3775 { 3776 struct dl_serinfo _info; 3777 struct fill_search_info_args args; 3778 3779 args.request = RTLD_DI_SERINFOSIZE; 3780 args.serinfo = &_info; 3781 3782 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3783 _info.dls_cnt = 0; 3784 3785 path_enumerate(obj->rpath, fill_search_info, &args); 3786 path_enumerate(ld_library_path, fill_search_info, &args); 3787 path_enumerate(obj->runpath, fill_search_info, &args); 3788 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3789 if (!obj->z_nodeflib) 3790 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3791 3792 3793 if (request == RTLD_DI_SERINFOSIZE) { 3794 info->dls_size = _info.dls_size; 3795 info->dls_cnt = _info.dls_cnt; 3796 return (0); 3797 } 3798 3799 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3800 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3801 return (-1); 3802 } 3803 3804 args.request = RTLD_DI_SERINFO; 3805 args.serinfo = info; 3806 args.serpath = &info->dls_serpath[0]; 3807 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3808 3809 args.flags = LA_SER_RUNPATH; 3810 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3811 return (-1); 3812 3813 args.flags = LA_SER_LIBPATH; 3814 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3815 return (-1); 3816 3817 args.flags = LA_SER_RUNPATH; 3818 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3819 return (-1); 3820 3821 args.flags = LA_SER_CONFIG; 3822 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3823 != NULL) 3824 return (-1); 3825 3826 args.flags = LA_SER_DEFAULT; 3827 if (!obj->z_nodeflib && 3828 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3829 return (-1); 3830 return (0); 3831 } 3832 3833 static int 3834 rtld_dirname(const char *path, char *bname) 3835 { 3836 const char *endp; 3837 3838 /* Empty or NULL string gets treated as "." */ 3839 if (path == NULL || *path == '\0') { 3840 bname[0] = '.'; 3841 bname[1] = '\0'; 3842 return (0); 3843 } 3844 3845 /* Strip trailing slashes */ 3846 endp = path + strlen(path) - 1; 3847 while (endp > path && *endp == '/') 3848 endp--; 3849 3850 /* Find the start of the dir */ 3851 while (endp > path && *endp != '/') 3852 endp--; 3853 3854 /* Either the dir is "/" or there are no slashes */ 3855 if (endp == path) { 3856 bname[0] = *endp == '/' ? '/' : '.'; 3857 bname[1] = '\0'; 3858 return (0); 3859 } else { 3860 do { 3861 endp--; 3862 } while (endp > path && *endp == '/'); 3863 } 3864 3865 if (endp - path + 2 > PATH_MAX) 3866 { 3867 _rtld_error("Filename is too long: %s", path); 3868 return(-1); 3869 } 3870 3871 strncpy(bname, path, endp - path + 1); 3872 bname[endp - path + 1] = '\0'; 3873 return (0); 3874 } 3875 3876 static int 3877 rtld_dirname_abs(const char *path, char *base) 3878 { 3879 char *last; 3880 3881 if (realpath(path, base) == NULL) 3882 return (-1); 3883 dbg("%s -> %s", path, base); 3884 last = strrchr(base, '/'); 3885 if (last == NULL) 3886 return (-1); 3887 if (last != base) 3888 *last = '\0'; 3889 return (0); 3890 } 3891 3892 static void 3893 linkmap_add(Obj_Entry *obj) 3894 { 3895 struct link_map *l = &obj->linkmap; 3896 struct link_map *prev; 3897 3898 obj->linkmap.l_name = obj->path; 3899 obj->linkmap.l_addr = obj->mapbase; 3900 obj->linkmap.l_ld = obj->dynamic; 3901 #ifdef __mips__ 3902 /* GDB needs load offset on MIPS to use the symbols */ 3903 obj->linkmap.l_offs = obj->relocbase; 3904 #endif 3905 3906 if (r_debug.r_map == NULL) { 3907 r_debug.r_map = l; 3908 return; 3909 } 3910 3911 /* 3912 * Scan to the end of the list, but not past the entry for the 3913 * dynamic linker, which we want to keep at the very end. 3914 */ 3915 for (prev = r_debug.r_map; 3916 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3917 prev = prev->l_next) 3918 ; 3919 3920 /* Link in the new entry. */ 3921 l->l_prev = prev; 3922 l->l_next = prev->l_next; 3923 if (l->l_next != NULL) 3924 l->l_next->l_prev = l; 3925 prev->l_next = l; 3926 } 3927 3928 static void 3929 linkmap_delete(Obj_Entry *obj) 3930 { 3931 struct link_map *l = &obj->linkmap; 3932 3933 if (l->l_prev == NULL) { 3934 if ((r_debug.r_map = l->l_next) != NULL) 3935 l->l_next->l_prev = NULL; 3936 return; 3937 } 3938 3939 if ((l->l_prev->l_next = l->l_next) != NULL) 3940 l->l_next->l_prev = l->l_prev; 3941 } 3942 3943 /* 3944 * Function for the debugger to set a breakpoint on to gain control. 3945 * 3946 * The two parameters allow the debugger to easily find and determine 3947 * what the runtime loader is doing and to whom it is doing it. 3948 * 3949 * When the loadhook trap is hit (r_debug_state, set at program 3950 * initialization), the arguments can be found on the stack: 3951 * 3952 * +8 struct link_map *m 3953 * +4 struct r_debug *rd 3954 * +0 RetAddr 3955 */ 3956 void 3957 r_debug_state(struct r_debug* rd, struct link_map *m) 3958 { 3959 /* 3960 * The following is a hack to force the compiler to emit calls to 3961 * this function, even when optimizing. If the function is empty, 3962 * the compiler is not obliged to emit any code for calls to it, 3963 * even when marked __noinline. However, gdb depends on those 3964 * calls being made. 3965 */ 3966 __compiler_membar(); 3967 } 3968 3969 /* 3970 * A function called after init routines have completed. This can be used to 3971 * break before a program's entry routine is called, and can be used when 3972 * main is not available in the symbol table. 3973 */ 3974 void 3975 _r_debug_postinit(struct link_map *m) 3976 { 3977 3978 /* See r_debug_state(). */ 3979 __compiler_membar(); 3980 } 3981 3982 static void 3983 release_object(Obj_Entry *obj) 3984 { 3985 3986 if (obj->holdcount > 0) { 3987 obj->unholdfree = true; 3988 return; 3989 } 3990 munmap(obj->mapbase, obj->mapsize); 3991 linkmap_delete(obj); 3992 obj_free(obj); 3993 } 3994 3995 /* 3996 * Get address of the pointer variable in the main program. 3997 * Prefer non-weak symbol over the weak one. 3998 */ 3999 static const void ** 4000 get_program_var_addr(const char *name, RtldLockState *lockstate) 4001 { 4002 SymLook req; 4003 DoneList donelist; 4004 4005 symlook_init(&req, name); 4006 req.lockstate = lockstate; 4007 donelist_init(&donelist); 4008 if (symlook_global(&req, &donelist) != 0) 4009 return (NULL); 4010 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4011 return ((const void **)make_function_pointer(req.sym_out, 4012 req.defobj_out)); 4013 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4014 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4015 else 4016 return ((const void **)(req.defobj_out->relocbase + 4017 req.sym_out->st_value)); 4018 } 4019 4020 /* 4021 * Set a pointer variable in the main program to the given value. This 4022 * is used to set key variables such as "environ" before any of the 4023 * init functions are called. 4024 */ 4025 static void 4026 set_program_var(const char *name, const void *value) 4027 { 4028 const void **addr; 4029 4030 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4031 dbg("\"%s\": *%p <-- %p", name, addr, value); 4032 *addr = value; 4033 } 4034 } 4035 4036 /* 4037 * Search the global objects, including dependencies and main object, 4038 * for the given symbol. 4039 */ 4040 static int 4041 symlook_global(SymLook *req, DoneList *donelist) 4042 { 4043 SymLook req1; 4044 const Objlist_Entry *elm; 4045 int res; 4046 4047 symlook_init_from_req(&req1, req); 4048 4049 /* Search all objects loaded at program start up. */ 4050 if (req->defobj_out == NULL || 4051 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4052 res = symlook_list(&req1, &list_main, donelist); 4053 if (res == 0 && (req->defobj_out == NULL || 4054 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4055 req->sym_out = req1.sym_out; 4056 req->defobj_out = req1.defobj_out; 4057 assert(req->defobj_out != NULL); 4058 } 4059 } 4060 4061 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4062 STAILQ_FOREACH(elm, &list_global, link) { 4063 if (req->defobj_out != NULL && 4064 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4065 break; 4066 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4067 if (res == 0 && (req->defobj_out == NULL || 4068 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4069 req->sym_out = req1.sym_out; 4070 req->defobj_out = req1.defobj_out; 4071 assert(req->defobj_out != NULL); 4072 } 4073 } 4074 4075 return (req->sym_out != NULL ? 0 : ESRCH); 4076 } 4077 4078 /* 4079 * Given a symbol name in a referencing object, find the corresponding 4080 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4081 * no definition was found. Returns a pointer to the Obj_Entry of the 4082 * defining object via the reference parameter DEFOBJ_OUT. 4083 */ 4084 static int 4085 symlook_default(SymLook *req, const Obj_Entry *refobj) 4086 { 4087 DoneList donelist; 4088 const Objlist_Entry *elm; 4089 SymLook req1; 4090 int res; 4091 4092 donelist_init(&donelist); 4093 symlook_init_from_req(&req1, req); 4094 4095 /* 4096 * Look first in the referencing object if linked symbolically, 4097 * and similarly handle protected symbols. 4098 */ 4099 res = symlook_obj(&req1, refobj); 4100 if (res == 0 && (refobj->symbolic || 4101 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4102 req->sym_out = req1.sym_out; 4103 req->defobj_out = req1.defobj_out; 4104 assert(req->defobj_out != NULL); 4105 } 4106 if (refobj->symbolic || req->defobj_out != NULL) 4107 donelist_check(&donelist, refobj); 4108 4109 symlook_global(req, &donelist); 4110 4111 /* Search all dlopened DAGs containing the referencing object. */ 4112 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4113 if (req->sym_out != NULL && 4114 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4115 break; 4116 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4117 if (res == 0 && (req->sym_out == NULL || 4118 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4119 req->sym_out = req1.sym_out; 4120 req->defobj_out = req1.defobj_out; 4121 assert(req->defobj_out != NULL); 4122 } 4123 } 4124 4125 /* 4126 * Search the dynamic linker itself, and possibly resolve the 4127 * symbol from there. This is how the application links to 4128 * dynamic linker services such as dlopen. 4129 */ 4130 if (req->sym_out == NULL || 4131 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4132 res = symlook_obj(&req1, &obj_rtld); 4133 if (res == 0) { 4134 req->sym_out = req1.sym_out; 4135 req->defobj_out = req1.defobj_out; 4136 assert(req->defobj_out != NULL); 4137 } 4138 } 4139 4140 return (req->sym_out != NULL ? 0 : ESRCH); 4141 } 4142 4143 static int 4144 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4145 { 4146 const Elf_Sym *def; 4147 const Obj_Entry *defobj; 4148 const Objlist_Entry *elm; 4149 SymLook req1; 4150 int res; 4151 4152 def = NULL; 4153 defobj = NULL; 4154 STAILQ_FOREACH(elm, objlist, link) { 4155 if (donelist_check(dlp, elm->obj)) 4156 continue; 4157 symlook_init_from_req(&req1, req); 4158 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4159 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4160 def = req1.sym_out; 4161 defobj = req1.defobj_out; 4162 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4163 break; 4164 } 4165 } 4166 } 4167 if (def != NULL) { 4168 req->sym_out = def; 4169 req->defobj_out = defobj; 4170 return (0); 4171 } 4172 return (ESRCH); 4173 } 4174 4175 /* 4176 * Search the chain of DAGS cointed to by the given Needed_Entry 4177 * for a symbol of the given name. Each DAG is scanned completely 4178 * before advancing to the next one. Returns a pointer to the symbol, 4179 * or NULL if no definition was found. 4180 */ 4181 static int 4182 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4183 { 4184 const Elf_Sym *def; 4185 const Needed_Entry *n; 4186 const Obj_Entry *defobj; 4187 SymLook req1; 4188 int res; 4189 4190 def = NULL; 4191 defobj = NULL; 4192 symlook_init_from_req(&req1, req); 4193 for (n = needed; n != NULL; n = n->next) { 4194 if (n->obj == NULL || 4195 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4196 continue; 4197 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4198 def = req1.sym_out; 4199 defobj = req1.defobj_out; 4200 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4201 break; 4202 } 4203 } 4204 if (def != NULL) { 4205 req->sym_out = def; 4206 req->defobj_out = defobj; 4207 return (0); 4208 } 4209 return (ESRCH); 4210 } 4211 4212 /* 4213 * Search the symbol table of a single shared object for a symbol of 4214 * the given name and version, if requested. Returns a pointer to the 4215 * symbol, or NULL if no definition was found. If the object is 4216 * filter, return filtered symbol from filtee. 4217 * 4218 * The symbol's hash value is passed in for efficiency reasons; that 4219 * eliminates many recomputations of the hash value. 4220 */ 4221 int 4222 symlook_obj(SymLook *req, const Obj_Entry *obj) 4223 { 4224 DoneList donelist; 4225 SymLook req1; 4226 int flags, res, mres; 4227 4228 /* 4229 * If there is at least one valid hash at this point, we prefer to 4230 * use the faster GNU version if available. 4231 */ 4232 if (obj->valid_hash_gnu) 4233 mres = symlook_obj1_gnu(req, obj); 4234 else if (obj->valid_hash_sysv) 4235 mres = symlook_obj1_sysv(req, obj); 4236 else 4237 return (EINVAL); 4238 4239 if (mres == 0) { 4240 if (obj->needed_filtees != NULL) { 4241 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4242 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4243 donelist_init(&donelist); 4244 symlook_init_from_req(&req1, req); 4245 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4246 if (res == 0) { 4247 req->sym_out = req1.sym_out; 4248 req->defobj_out = req1.defobj_out; 4249 } 4250 return (res); 4251 } 4252 if (obj->needed_aux_filtees != NULL) { 4253 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4254 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4255 donelist_init(&donelist); 4256 symlook_init_from_req(&req1, req); 4257 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4258 if (res == 0) { 4259 req->sym_out = req1.sym_out; 4260 req->defobj_out = req1.defobj_out; 4261 return (res); 4262 } 4263 } 4264 } 4265 return (mres); 4266 } 4267 4268 /* Symbol match routine common to both hash functions */ 4269 static bool 4270 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4271 const unsigned long symnum) 4272 { 4273 Elf_Versym verndx; 4274 const Elf_Sym *symp; 4275 const char *strp; 4276 4277 symp = obj->symtab + symnum; 4278 strp = obj->strtab + symp->st_name; 4279 4280 switch (ELF_ST_TYPE(symp->st_info)) { 4281 case STT_FUNC: 4282 case STT_NOTYPE: 4283 case STT_OBJECT: 4284 case STT_COMMON: 4285 case STT_GNU_IFUNC: 4286 if (symp->st_value == 0) 4287 return (false); 4288 /* fallthrough */ 4289 case STT_TLS: 4290 if (symp->st_shndx != SHN_UNDEF) 4291 break; 4292 #ifndef __mips__ 4293 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4294 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4295 break; 4296 /* fallthrough */ 4297 #endif 4298 default: 4299 return (false); 4300 } 4301 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4302 return (false); 4303 4304 if (req->ventry == NULL) { 4305 if (obj->versyms != NULL) { 4306 verndx = VER_NDX(obj->versyms[symnum]); 4307 if (verndx > obj->vernum) { 4308 _rtld_error( 4309 "%s: symbol %s references wrong version %d", 4310 obj->path, obj->strtab + symnum, verndx); 4311 return (false); 4312 } 4313 /* 4314 * If we are not called from dlsym (i.e. this 4315 * is a normal relocation from unversioned 4316 * binary), accept the symbol immediately if 4317 * it happens to have first version after this 4318 * shared object became versioned. Otherwise, 4319 * if symbol is versioned and not hidden, 4320 * remember it. If it is the only symbol with 4321 * this name exported by the shared object, it 4322 * will be returned as a match by the calling 4323 * function. If symbol is global (verndx < 2) 4324 * accept it unconditionally. 4325 */ 4326 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4327 verndx == VER_NDX_GIVEN) { 4328 result->sym_out = symp; 4329 return (true); 4330 } 4331 else if (verndx >= VER_NDX_GIVEN) { 4332 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4333 == 0) { 4334 if (result->vsymp == NULL) 4335 result->vsymp = symp; 4336 result->vcount++; 4337 } 4338 return (false); 4339 } 4340 } 4341 result->sym_out = symp; 4342 return (true); 4343 } 4344 if (obj->versyms == NULL) { 4345 if (object_match_name(obj, req->ventry->name)) { 4346 _rtld_error("%s: object %s should provide version %s " 4347 "for symbol %s", obj_rtld.path, obj->path, 4348 req->ventry->name, obj->strtab + symnum); 4349 return (false); 4350 } 4351 } else { 4352 verndx = VER_NDX(obj->versyms[symnum]); 4353 if (verndx > obj->vernum) { 4354 _rtld_error("%s: symbol %s references wrong version %d", 4355 obj->path, obj->strtab + symnum, verndx); 4356 return (false); 4357 } 4358 if (obj->vertab[verndx].hash != req->ventry->hash || 4359 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4360 /* 4361 * Version does not match. Look if this is a 4362 * global symbol and if it is not hidden. If 4363 * global symbol (verndx < 2) is available, 4364 * use it. Do not return symbol if we are 4365 * called by dlvsym, because dlvsym looks for 4366 * a specific version and default one is not 4367 * what dlvsym wants. 4368 */ 4369 if ((req->flags & SYMLOOK_DLSYM) || 4370 (verndx >= VER_NDX_GIVEN) || 4371 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4372 return (false); 4373 } 4374 } 4375 result->sym_out = symp; 4376 return (true); 4377 } 4378 4379 /* 4380 * Search for symbol using SysV hash function. 4381 * obj->buckets is known not to be NULL at this point; the test for this was 4382 * performed with the obj->valid_hash_sysv assignment. 4383 */ 4384 static int 4385 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4386 { 4387 unsigned long symnum; 4388 Sym_Match_Result matchres; 4389 4390 matchres.sym_out = NULL; 4391 matchres.vsymp = NULL; 4392 matchres.vcount = 0; 4393 4394 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4395 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4396 if (symnum >= obj->nchains) 4397 return (ESRCH); /* Bad object */ 4398 4399 if (matched_symbol(req, obj, &matchres, symnum)) { 4400 req->sym_out = matchres.sym_out; 4401 req->defobj_out = obj; 4402 return (0); 4403 } 4404 } 4405 if (matchres.vcount == 1) { 4406 req->sym_out = matchres.vsymp; 4407 req->defobj_out = obj; 4408 return (0); 4409 } 4410 return (ESRCH); 4411 } 4412 4413 /* Search for symbol using GNU hash function */ 4414 static int 4415 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4416 { 4417 Elf_Addr bloom_word; 4418 const Elf32_Word *hashval; 4419 Elf32_Word bucket; 4420 Sym_Match_Result matchres; 4421 unsigned int h1, h2; 4422 unsigned long symnum; 4423 4424 matchres.sym_out = NULL; 4425 matchres.vsymp = NULL; 4426 matchres.vcount = 0; 4427 4428 /* Pick right bitmask word from Bloom filter array */ 4429 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4430 obj->maskwords_bm_gnu]; 4431 4432 /* Calculate modulus word size of gnu hash and its derivative */ 4433 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4434 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4435 4436 /* Filter out the "definitely not in set" queries */ 4437 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4438 return (ESRCH); 4439 4440 /* Locate hash chain and corresponding value element*/ 4441 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4442 if (bucket == 0) 4443 return (ESRCH); 4444 hashval = &obj->chain_zero_gnu[bucket]; 4445 do { 4446 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4447 symnum = hashval - obj->chain_zero_gnu; 4448 if (matched_symbol(req, obj, &matchres, symnum)) { 4449 req->sym_out = matchres.sym_out; 4450 req->defobj_out = obj; 4451 return (0); 4452 } 4453 } 4454 } while ((*hashval++ & 1) == 0); 4455 if (matchres.vcount == 1) { 4456 req->sym_out = matchres.vsymp; 4457 req->defobj_out = obj; 4458 return (0); 4459 } 4460 return (ESRCH); 4461 } 4462 4463 static void 4464 trace_loaded_objects(Obj_Entry *obj) 4465 { 4466 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4467 int c; 4468 4469 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4470 main_local = ""; 4471 4472 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4473 fmt1 = "\t%o => %p (%x)\n"; 4474 4475 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4476 fmt2 = "\t%o (%x)\n"; 4477 4478 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4479 4480 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4481 Needed_Entry *needed; 4482 char *name, *path; 4483 bool is_lib; 4484 4485 if (obj->marker) 4486 continue; 4487 if (list_containers && obj->needed != NULL) 4488 rtld_printf("%s:\n", obj->path); 4489 for (needed = obj->needed; needed; needed = needed->next) { 4490 if (needed->obj != NULL) { 4491 if (needed->obj->traced && !list_containers) 4492 continue; 4493 needed->obj->traced = true; 4494 path = needed->obj->path; 4495 } else 4496 path = "not found"; 4497 4498 name = (char *)obj->strtab + needed->name; 4499 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4500 4501 fmt = is_lib ? fmt1 : fmt2; 4502 while ((c = *fmt++) != '\0') { 4503 switch (c) { 4504 default: 4505 rtld_putchar(c); 4506 continue; 4507 case '\\': 4508 switch (c = *fmt) { 4509 case '\0': 4510 continue; 4511 case 'n': 4512 rtld_putchar('\n'); 4513 break; 4514 case 't': 4515 rtld_putchar('\t'); 4516 break; 4517 } 4518 break; 4519 case '%': 4520 switch (c = *fmt) { 4521 case '\0': 4522 continue; 4523 case '%': 4524 default: 4525 rtld_putchar(c); 4526 break; 4527 case 'A': 4528 rtld_putstr(main_local); 4529 break; 4530 case 'a': 4531 rtld_putstr(obj_main->path); 4532 break; 4533 case 'o': 4534 rtld_putstr(name); 4535 break; 4536 #if 0 4537 case 'm': 4538 rtld_printf("%d", sodp->sod_major); 4539 break; 4540 case 'n': 4541 rtld_printf("%d", sodp->sod_minor); 4542 break; 4543 #endif 4544 case 'p': 4545 rtld_putstr(path); 4546 break; 4547 case 'x': 4548 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4549 0); 4550 break; 4551 } 4552 break; 4553 } 4554 ++fmt; 4555 } 4556 } 4557 } 4558 } 4559 4560 /* 4561 * Unload a dlopened object and its dependencies from memory and from 4562 * our data structures. It is assumed that the DAG rooted in the 4563 * object has already been unreferenced, and that the object has a 4564 * reference count of 0. 4565 */ 4566 static void 4567 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4568 { 4569 Obj_Entry marker, *obj, *next; 4570 4571 assert(root->refcount == 0); 4572 4573 /* 4574 * Pass over the DAG removing unreferenced objects from 4575 * appropriate lists. 4576 */ 4577 unlink_object(root); 4578 4579 /* Unmap all objects that are no longer referenced. */ 4580 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4581 next = TAILQ_NEXT(obj, next); 4582 if (obj->marker || obj->refcount != 0) 4583 continue; 4584 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4585 obj->mapsize, 0, obj->path); 4586 dbg("unloading \"%s\"", obj->path); 4587 /* 4588 * Unlink the object now to prevent new references from 4589 * being acquired while the bind lock is dropped in 4590 * recursive dlclose() invocations. 4591 */ 4592 TAILQ_REMOVE(&obj_list, obj, next); 4593 obj_count--; 4594 4595 if (obj->filtees_loaded) { 4596 if (next != NULL) { 4597 init_marker(&marker); 4598 TAILQ_INSERT_BEFORE(next, &marker, next); 4599 unload_filtees(obj, lockstate); 4600 next = TAILQ_NEXT(&marker, next); 4601 TAILQ_REMOVE(&obj_list, &marker, next); 4602 } else 4603 unload_filtees(obj, lockstate); 4604 } 4605 release_object(obj); 4606 } 4607 } 4608 4609 static void 4610 unlink_object(Obj_Entry *root) 4611 { 4612 Objlist_Entry *elm; 4613 4614 if (root->refcount == 0) { 4615 /* Remove the object from the RTLD_GLOBAL list. */ 4616 objlist_remove(&list_global, root); 4617 4618 /* Remove the object from all objects' DAG lists. */ 4619 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4620 objlist_remove(&elm->obj->dldags, root); 4621 if (elm->obj != root) 4622 unlink_object(elm->obj); 4623 } 4624 } 4625 } 4626 4627 static void 4628 ref_dag(Obj_Entry *root) 4629 { 4630 Objlist_Entry *elm; 4631 4632 assert(root->dag_inited); 4633 STAILQ_FOREACH(elm, &root->dagmembers, link) 4634 elm->obj->refcount++; 4635 } 4636 4637 static void 4638 unref_dag(Obj_Entry *root) 4639 { 4640 Objlist_Entry *elm; 4641 4642 assert(root->dag_inited); 4643 STAILQ_FOREACH(elm, &root->dagmembers, link) 4644 elm->obj->refcount--; 4645 } 4646 4647 /* 4648 * Common code for MD __tls_get_addr(). 4649 */ 4650 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4651 static void * 4652 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4653 { 4654 Elf_Addr *newdtv, *dtv; 4655 RtldLockState lockstate; 4656 int to_copy; 4657 4658 dtv = *dtvp; 4659 /* Check dtv generation in case new modules have arrived */ 4660 if (dtv[0] != tls_dtv_generation) { 4661 wlock_acquire(rtld_bind_lock, &lockstate); 4662 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4663 to_copy = dtv[1]; 4664 if (to_copy > tls_max_index) 4665 to_copy = tls_max_index; 4666 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4667 newdtv[0] = tls_dtv_generation; 4668 newdtv[1] = tls_max_index; 4669 free(dtv); 4670 lock_release(rtld_bind_lock, &lockstate); 4671 dtv = *dtvp = newdtv; 4672 } 4673 4674 /* Dynamically allocate module TLS if necessary */ 4675 if (dtv[index + 1] == 0) { 4676 /* Signal safe, wlock will block out signals. */ 4677 wlock_acquire(rtld_bind_lock, &lockstate); 4678 if (!dtv[index + 1]) 4679 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4680 lock_release(rtld_bind_lock, &lockstate); 4681 } 4682 return ((void *)(dtv[index + 1] + offset)); 4683 } 4684 4685 void * 4686 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4687 { 4688 Elf_Addr *dtv; 4689 4690 dtv = *dtvp; 4691 /* Check dtv generation in case new modules have arrived */ 4692 if (__predict_true(dtv[0] == tls_dtv_generation && 4693 dtv[index + 1] != 0)) 4694 return ((void *)(dtv[index + 1] + offset)); 4695 return (tls_get_addr_slow(dtvp, index, offset)); 4696 } 4697 4698 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4699 defined(__powerpc__) || defined(__riscv) 4700 4701 /* 4702 * Allocate Static TLS using the Variant I method. 4703 */ 4704 void * 4705 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4706 { 4707 Obj_Entry *obj; 4708 char *tcb; 4709 Elf_Addr **tls; 4710 Elf_Addr *dtv; 4711 Elf_Addr addr; 4712 int i; 4713 4714 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4715 return (oldtcb); 4716 4717 assert(tcbsize >= TLS_TCB_SIZE); 4718 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4719 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4720 4721 if (oldtcb != NULL) { 4722 memcpy(tls, oldtcb, tls_static_space); 4723 free(oldtcb); 4724 4725 /* Adjust the DTV. */ 4726 dtv = tls[0]; 4727 for (i = 0; i < dtv[1]; i++) { 4728 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4729 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4730 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4731 } 4732 } 4733 } else { 4734 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4735 tls[0] = dtv; 4736 dtv[0] = tls_dtv_generation; 4737 dtv[1] = tls_max_index; 4738 4739 for (obj = globallist_curr(objs); obj != NULL; 4740 obj = globallist_next(obj)) { 4741 if (obj->tlsoffset > 0) { 4742 addr = (Elf_Addr)tls + obj->tlsoffset; 4743 if (obj->tlsinitsize > 0) 4744 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4745 if (obj->tlssize > obj->tlsinitsize) 4746 memset((void*) (addr + obj->tlsinitsize), 0, 4747 obj->tlssize - obj->tlsinitsize); 4748 dtv[obj->tlsindex + 1] = addr; 4749 } 4750 } 4751 } 4752 4753 return (tcb); 4754 } 4755 4756 void 4757 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4758 { 4759 Elf_Addr *dtv; 4760 Elf_Addr tlsstart, tlsend; 4761 int dtvsize, i; 4762 4763 assert(tcbsize >= TLS_TCB_SIZE); 4764 4765 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4766 tlsend = tlsstart + tls_static_space; 4767 4768 dtv = *(Elf_Addr **)tlsstart; 4769 dtvsize = dtv[1]; 4770 for (i = 0; i < dtvsize; i++) { 4771 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4772 free((void*)dtv[i+2]); 4773 } 4774 } 4775 free(dtv); 4776 free(tcb); 4777 } 4778 4779 #endif 4780 4781 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4782 4783 /* 4784 * Allocate Static TLS using the Variant II method. 4785 */ 4786 void * 4787 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4788 { 4789 Obj_Entry *obj; 4790 size_t size, ralign; 4791 char *tls; 4792 Elf_Addr *dtv, *olddtv; 4793 Elf_Addr segbase, oldsegbase, addr; 4794 int i; 4795 4796 ralign = tcbalign; 4797 if (tls_static_max_align > ralign) 4798 ralign = tls_static_max_align; 4799 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4800 4801 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4802 tls = malloc_aligned(size, ralign); 4803 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4804 4805 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4806 ((Elf_Addr*)segbase)[0] = segbase; 4807 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4808 4809 dtv[0] = tls_dtv_generation; 4810 dtv[1] = tls_max_index; 4811 4812 if (oldtls) { 4813 /* 4814 * Copy the static TLS block over whole. 4815 */ 4816 oldsegbase = (Elf_Addr) oldtls; 4817 memcpy((void *)(segbase - tls_static_space), 4818 (const void *)(oldsegbase - tls_static_space), 4819 tls_static_space); 4820 4821 /* 4822 * If any dynamic TLS blocks have been created tls_get_addr(), 4823 * move them over. 4824 */ 4825 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4826 for (i = 0; i < olddtv[1]; i++) { 4827 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4828 dtv[i+2] = olddtv[i+2]; 4829 olddtv[i+2] = 0; 4830 } 4831 } 4832 4833 /* 4834 * We assume that this block was the one we created with 4835 * allocate_initial_tls(). 4836 */ 4837 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4838 } else { 4839 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4840 if (obj->marker || obj->tlsoffset == 0) 4841 continue; 4842 addr = segbase - obj->tlsoffset; 4843 memset((void*) (addr + obj->tlsinitsize), 4844 0, obj->tlssize - obj->tlsinitsize); 4845 if (obj->tlsinit) 4846 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4847 dtv[obj->tlsindex + 1] = addr; 4848 } 4849 } 4850 4851 return (void*) segbase; 4852 } 4853 4854 void 4855 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4856 { 4857 Elf_Addr* dtv; 4858 size_t size, ralign; 4859 int dtvsize, i; 4860 Elf_Addr tlsstart, tlsend; 4861 4862 /* 4863 * Figure out the size of the initial TLS block so that we can 4864 * find stuff which ___tls_get_addr() allocated dynamically. 4865 */ 4866 ralign = tcbalign; 4867 if (tls_static_max_align > ralign) 4868 ralign = tls_static_max_align; 4869 size = round(tls_static_space, ralign); 4870 4871 dtv = ((Elf_Addr**)tls)[1]; 4872 dtvsize = dtv[1]; 4873 tlsend = (Elf_Addr) tls; 4874 tlsstart = tlsend - size; 4875 for (i = 0; i < dtvsize; i++) { 4876 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4877 free_aligned((void *)dtv[i + 2]); 4878 } 4879 } 4880 4881 free_aligned((void *)tlsstart); 4882 free((void*) dtv); 4883 } 4884 4885 #endif 4886 4887 /* 4888 * Allocate TLS block for module with given index. 4889 */ 4890 void * 4891 allocate_module_tls(int index) 4892 { 4893 Obj_Entry* obj; 4894 char* p; 4895 4896 TAILQ_FOREACH(obj, &obj_list, next) { 4897 if (obj->marker) 4898 continue; 4899 if (obj->tlsindex == index) 4900 break; 4901 } 4902 if (!obj) { 4903 _rtld_error("Can't find module with TLS index %d", index); 4904 rtld_die(); 4905 } 4906 4907 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4908 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4909 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4910 4911 return p; 4912 } 4913 4914 bool 4915 allocate_tls_offset(Obj_Entry *obj) 4916 { 4917 size_t off; 4918 4919 if (obj->tls_done) 4920 return true; 4921 4922 if (obj->tlssize == 0) { 4923 obj->tls_done = true; 4924 return true; 4925 } 4926 4927 if (tls_last_offset == 0) 4928 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4929 else 4930 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4931 obj->tlssize, obj->tlsalign); 4932 4933 /* 4934 * If we have already fixed the size of the static TLS block, we 4935 * must stay within that size. When allocating the static TLS, we 4936 * leave a small amount of space spare to be used for dynamically 4937 * loading modules which use static TLS. 4938 */ 4939 if (tls_static_space != 0) { 4940 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4941 return false; 4942 } else if (obj->tlsalign > tls_static_max_align) { 4943 tls_static_max_align = obj->tlsalign; 4944 } 4945 4946 tls_last_offset = obj->tlsoffset = off; 4947 tls_last_size = obj->tlssize; 4948 obj->tls_done = true; 4949 4950 return true; 4951 } 4952 4953 void 4954 free_tls_offset(Obj_Entry *obj) 4955 { 4956 4957 /* 4958 * If we were the last thing to allocate out of the static TLS 4959 * block, we give our space back to the 'allocator'. This is a 4960 * simplistic workaround to allow libGL.so.1 to be loaded and 4961 * unloaded multiple times. 4962 */ 4963 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4964 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4965 tls_last_offset -= obj->tlssize; 4966 tls_last_size = 0; 4967 } 4968 } 4969 4970 void * 4971 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4972 { 4973 void *ret; 4974 RtldLockState lockstate; 4975 4976 wlock_acquire(rtld_bind_lock, &lockstate); 4977 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4978 tcbsize, tcbalign); 4979 lock_release(rtld_bind_lock, &lockstate); 4980 return (ret); 4981 } 4982 4983 void 4984 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4985 { 4986 RtldLockState lockstate; 4987 4988 wlock_acquire(rtld_bind_lock, &lockstate); 4989 free_tls(tcb, tcbsize, tcbalign); 4990 lock_release(rtld_bind_lock, &lockstate); 4991 } 4992 4993 static void 4994 object_add_name(Obj_Entry *obj, const char *name) 4995 { 4996 Name_Entry *entry; 4997 size_t len; 4998 4999 len = strlen(name); 5000 entry = malloc(sizeof(Name_Entry) + len); 5001 5002 if (entry != NULL) { 5003 strcpy(entry->name, name); 5004 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5005 } 5006 } 5007 5008 static int 5009 object_match_name(const Obj_Entry *obj, const char *name) 5010 { 5011 Name_Entry *entry; 5012 5013 STAILQ_FOREACH(entry, &obj->names, link) { 5014 if (strcmp(name, entry->name) == 0) 5015 return (1); 5016 } 5017 return (0); 5018 } 5019 5020 static Obj_Entry * 5021 locate_dependency(const Obj_Entry *obj, const char *name) 5022 { 5023 const Objlist_Entry *entry; 5024 const Needed_Entry *needed; 5025 5026 STAILQ_FOREACH(entry, &list_main, link) { 5027 if (object_match_name(entry->obj, name)) 5028 return entry->obj; 5029 } 5030 5031 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5032 if (strcmp(obj->strtab + needed->name, name) == 0 || 5033 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5034 /* 5035 * If there is DT_NEEDED for the name we are looking for, 5036 * we are all set. Note that object might not be found if 5037 * dependency was not loaded yet, so the function can 5038 * return NULL here. This is expected and handled 5039 * properly by the caller. 5040 */ 5041 return (needed->obj); 5042 } 5043 } 5044 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5045 obj->path, name); 5046 rtld_die(); 5047 } 5048 5049 static int 5050 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5051 const Elf_Vernaux *vna) 5052 { 5053 const Elf_Verdef *vd; 5054 const char *vername; 5055 5056 vername = refobj->strtab + vna->vna_name; 5057 vd = depobj->verdef; 5058 if (vd == NULL) { 5059 _rtld_error("%s: version %s required by %s not defined", 5060 depobj->path, vername, refobj->path); 5061 return (-1); 5062 } 5063 for (;;) { 5064 if (vd->vd_version != VER_DEF_CURRENT) { 5065 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5066 depobj->path, vd->vd_version); 5067 return (-1); 5068 } 5069 if (vna->vna_hash == vd->vd_hash) { 5070 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5071 ((char *)vd + vd->vd_aux); 5072 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5073 return (0); 5074 } 5075 if (vd->vd_next == 0) 5076 break; 5077 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5078 } 5079 if (vna->vna_flags & VER_FLG_WEAK) 5080 return (0); 5081 _rtld_error("%s: version %s required by %s not found", 5082 depobj->path, vername, refobj->path); 5083 return (-1); 5084 } 5085 5086 static int 5087 rtld_verify_object_versions(Obj_Entry *obj) 5088 { 5089 const Elf_Verneed *vn; 5090 const Elf_Verdef *vd; 5091 const Elf_Verdaux *vda; 5092 const Elf_Vernaux *vna; 5093 const Obj_Entry *depobj; 5094 int maxvernum, vernum; 5095 5096 if (obj->ver_checked) 5097 return (0); 5098 obj->ver_checked = true; 5099 5100 maxvernum = 0; 5101 /* 5102 * Walk over defined and required version records and figure out 5103 * max index used by any of them. Do very basic sanity checking 5104 * while there. 5105 */ 5106 vn = obj->verneed; 5107 while (vn != NULL) { 5108 if (vn->vn_version != VER_NEED_CURRENT) { 5109 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5110 obj->path, vn->vn_version); 5111 return (-1); 5112 } 5113 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5114 for (;;) { 5115 vernum = VER_NEED_IDX(vna->vna_other); 5116 if (vernum > maxvernum) 5117 maxvernum = vernum; 5118 if (vna->vna_next == 0) 5119 break; 5120 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5121 } 5122 if (vn->vn_next == 0) 5123 break; 5124 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5125 } 5126 5127 vd = obj->verdef; 5128 while (vd != NULL) { 5129 if (vd->vd_version != VER_DEF_CURRENT) { 5130 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5131 obj->path, vd->vd_version); 5132 return (-1); 5133 } 5134 vernum = VER_DEF_IDX(vd->vd_ndx); 5135 if (vernum > maxvernum) 5136 maxvernum = vernum; 5137 if (vd->vd_next == 0) 5138 break; 5139 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5140 } 5141 5142 if (maxvernum == 0) 5143 return (0); 5144 5145 /* 5146 * Store version information in array indexable by version index. 5147 * Verify that object version requirements are satisfied along the 5148 * way. 5149 */ 5150 obj->vernum = maxvernum + 1; 5151 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5152 5153 vd = obj->verdef; 5154 while (vd != NULL) { 5155 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5156 vernum = VER_DEF_IDX(vd->vd_ndx); 5157 assert(vernum <= maxvernum); 5158 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5159 obj->vertab[vernum].hash = vd->vd_hash; 5160 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5161 obj->vertab[vernum].file = NULL; 5162 obj->vertab[vernum].flags = 0; 5163 } 5164 if (vd->vd_next == 0) 5165 break; 5166 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5167 } 5168 5169 vn = obj->verneed; 5170 while (vn != NULL) { 5171 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5172 if (depobj == NULL) 5173 return (-1); 5174 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5175 for (;;) { 5176 if (check_object_provided_version(obj, depobj, vna)) 5177 return (-1); 5178 vernum = VER_NEED_IDX(vna->vna_other); 5179 assert(vernum <= maxvernum); 5180 obj->vertab[vernum].hash = vna->vna_hash; 5181 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5182 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5183 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5184 VER_INFO_HIDDEN : 0; 5185 if (vna->vna_next == 0) 5186 break; 5187 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5188 } 5189 if (vn->vn_next == 0) 5190 break; 5191 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5192 } 5193 return 0; 5194 } 5195 5196 static int 5197 rtld_verify_versions(const Objlist *objlist) 5198 { 5199 Objlist_Entry *entry; 5200 int rc; 5201 5202 rc = 0; 5203 STAILQ_FOREACH(entry, objlist, link) { 5204 /* 5205 * Skip dummy objects or objects that have their version requirements 5206 * already checked. 5207 */ 5208 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5209 continue; 5210 if (rtld_verify_object_versions(entry->obj) == -1) { 5211 rc = -1; 5212 if (ld_tracing == NULL) 5213 break; 5214 } 5215 } 5216 if (rc == 0 || ld_tracing != NULL) 5217 rc = rtld_verify_object_versions(&obj_rtld); 5218 return rc; 5219 } 5220 5221 const Ver_Entry * 5222 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5223 { 5224 Elf_Versym vernum; 5225 5226 if (obj->vertab) { 5227 vernum = VER_NDX(obj->versyms[symnum]); 5228 if (vernum >= obj->vernum) { 5229 _rtld_error("%s: symbol %s has wrong verneed value %d", 5230 obj->path, obj->strtab + symnum, vernum); 5231 } else if (obj->vertab[vernum].hash != 0) { 5232 return &obj->vertab[vernum]; 5233 } 5234 } 5235 return NULL; 5236 } 5237 5238 int 5239 _rtld_get_stack_prot(void) 5240 { 5241 5242 return (stack_prot); 5243 } 5244 5245 int 5246 _rtld_is_dlopened(void *arg) 5247 { 5248 Obj_Entry *obj; 5249 RtldLockState lockstate; 5250 int res; 5251 5252 rlock_acquire(rtld_bind_lock, &lockstate); 5253 obj = dlcheck(arg); 5254 if (obj == NULL) 5255 obj = obj_from_addr(arg); 5256 if (obj == NULL) { 5257 _rtld_error("No shared object contains address"); 5258 lock_release(rtld_bind_lock, &lockstate); 5259 return (-1); 5260 } 5261 res = obj->dlopened ? 1 : 0; 5262 lock_release(rtld_bind_lock, &lockstate); 5263 return (res); 5264 } 5265 5266 int 5267 obj_enforce_relro(Obj_Entry *obj) 5268 { 5269 5270 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5271 PROT_READ) == -1) { 5272 _rtld_error("%s: Cannot enforce relro protection: %s", 5273 obj->path, rtld_strerror(errno)); 5274 return (-1); 5275 } 5276 return (0); 5277 } 5278 5279 static void 5280 map_stacks_exec(RtldLockState *lockstate) 5281 { 5282 void (*thr_map_stacks_exec)(void); 5283 5284 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5285 return; 5286 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5287 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5288 if (thr_map_stacks_exec != NULL) { 5289 stack_prot |= PROT_EXEC; 5290 thr_map_stacks_exec(); 5291 } 5292 } 5293 5294 void 5295 symlook_init(SymLook *dst, const char *name) 5296 { 5297 5298 bzero(dst, sizeof(*dst)); 5299 dst->name = name; 5300 dst->hash = elf_hash(name); 5301 dst->hash_gnu = gnu_hash(name); 5302 } 5303 5304 static void 5305 symlook_init_from_req(SymLook *dst, const SymLook *src) 5306 { 5307 5308 dst->name = src->name; 5309 dst->hash = src->hash; 5310 dst->hash_gnu = src->hash_gnu; 5311 dst->ventry = src->ventry; 5312 dst->flags = src->flags; 5313 dst->defobj_out = NULL; 5314 dst->sym_out = NULL; 5315 dst->lockstate = src->lockstate; 5316 } 5317 5318 static int 5319 open_binary_fd(const char *argv0, bool search_in_path) 5320 { 5321 char *pathenv, *pe, binpath[PATH_MAX]; 5322 int fd; 5323 5324 if (search_in_path && strchr(argv0, '/') == NULL) { 5325 pathenv = getenv("PATH"); 5326 if (pathenv == NULL) { 5327 rtld_printf("-p and no PATH environment variable\n"); 5328 rtld_die(); 5329 } 5330 pathenv = strdup(pathenv); 5331 if (pathenv == NULL) { 5332 rtld_printf("Cannot allocate memory\n"); 5333 rtld_die(); 5334 } 5335 fd = -1; 5336 errno = ENOENT; 5337 while ((pe = strsep(&pathenv, ":")) != NULL) { 5338 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5339 sizeof(binpath)) 5340 continue; 5341 if (binpath[0] != '\0' && 5342 strlcat(binpath, "/", sizeof(binpath)) >= 5343 sizeof(binpath)) 5344 continue; 5345 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5346 sizeof(binpath)) 5347 continue; 5348 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5349 if (fd != -1 || errno != ENOENT) 5350 break; 5351 } 5352 free(pathenv); 5353 } else { 5354 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5355 } 5356 5357 if (fd == -1) { 5358 rtld_printf("Opening %s: %s\n", argv0, 5359 rtld_strerror(errno)); 5360 rtld_die(); 5361 } 5362 return (fd); 5363 } 5364 5365 /* 5366 * Parse a set of command-line arguments. 5367 */ 5368 static int 5369 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5370 { 5371 const char *arg; 5372 int fd, i, j, arglen; 5373 char opt; 5374 5375 dbg("Parsing command-line arguments"); 5376 *use_pathp = false; 5377 *fdp = -1; 5378 5379 for (i = 1; i < argc; i++ ) { 5380 arg = argv[i]; 5381 dbg("argv[%d]: '%s'", i, arg); 5382 5383 /* 5384 * rtld arguments end with an explicit "--" or with the first 5385 * non-prefixed argument. 5386 */ 5387 if (strcmp(arg, "--") == 0) { 5388 i++; 5389 break; 5390 } 5391 if (arg[0] != '-') 5392 break; 5393 5394 /* 5395 * All other arguments are single-character options that can 5396 * be combined, so we need to search through `arg` for them. 5397 */ 5398 arglen = strlen(arg); 5399 for (j = 1; j < arglen; j++) { 5400 opt = arg[j]; 5401 if (opt == 'h') { 5402 print_usage(argv[0]); 5403 rtld_die(); 5404 } else if (opt == 'f') { 5405 /* 5406 * -f XX can be used to specify a descriptor for the 5407 * binary named at the command line (i.e., the later 5408 * argument will specify the process name but the 5409 * descriptor is what will actually be executed) 5410 */ 5411 if (j != arglen - 1) { 5412 /* -f must be the last option in, e.g., -abcf */ 5413 _rtld_error("invalid options: %s", arg); 5414 rtld_die(); 5415 } 5416 i++; 5417 fd = parse_integer(argv[i]); 5418 if (fd == -1) { 5419 _rtld_error("invalid file descriptor: '%s'", 5420 argv[i]); 5421 rtld_die(); 5422 } 5423 *fdp = fd; 5424 break; 5425 } else if (opt == 'p') { 5426 *use_pathp = true; 5427 } else { 5428 rtld_printf("invalid argument: '%s'\n", arg); 5429 print_usage(argv[0]); 5430 rtld_die(); 5431 } 5432 } 5433 } 5434 5435 return (i); 5436 } 5437 5438 /* 5439 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5440 */ 5441 static int 5442 parse_integer(const char *str) 5443 { 5444 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5445 const char *orig; 5446 int n; 5447 char c; 5448 5449 orig = str; 5450 n = 0; 5451 for (c = *str; c != '\0'; c = *++str) { 5452 if (c < '0' || c > '9') 5453 return (-1); 5454 5455 n *= RADIX; 5456 n += c - '0'; 5457 } 5458 5459 /* Make sure we actually parsed something. */ 5460 if (str == orig) 5461 return (-1); 5462 return (n); 5463 } 5464 5465 static void 5466 print_usage(const char *argv0) 5467 { 5468 5469 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5470 "\n" 5471 "Options:\n" 5472 " -h Display this help message\n" 5473 " -p Search in PATH for named binary\n" 5474 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5475 " -- End of RTLD options\n" 5476 " <binary> Name of process to execute\n" 5477 " <args> Arguments to the executed process\n", argv0); 5478 } 5479 5480 /* 5481 * Overrides for libc_pic-provided functions. 5482 */ 5483 5484 int 5485 __getosreldate(void) 5486 { 5487 size_t len; 5488 int oid[2]; 5489 int error, osrel; 5490 5491 if (osreldate != 0) 5492 return (osreldate); 5493 5494 oid[0] = CTL_KERN; 5495 oid[1] = KERN_OSRELDATE; 5496 osrel = 0; 5497 len = sizeof(osrel); 5498 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5499 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5500 osreldate = osrel; 5501 return (osreldate); 5502 } 5503 5504 void 5505 exit(int status) 5506 { 5507 5508 _exit(status); 5509 } 5510 5511 void (*__cleanup)(void); 5512 int __isthreaded = 0; 5513 int _thread_autoinit_dummy_decl = 1; 5514 5515 /* 5516 * No unresolved symbols for rtld. 5517 */ 5518 void 5519 __pthread_cxa_finalize(struct dl_phdr_info *a) 5520 { 5521 } 5522 5523 void 5524 __stack_chk_fail(void) 5525 { 5526 5527 _rtld_error("stack overflow detected; terminated"); 5528 rtld_die(); 5529 } 5530 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5531 5532 void 5533 __chk_fail(void) 5534 { 5535 5536 _rtld_error("buffer overflow detected; terminated"); 5537 rtld_die(); 5538 } 5539 5540 const char * 5541 rtld_strerror(int errnum) 5542 { 5543 5544 if (errnum < 0 || errnum >= sys_nerr) 5545 return ("Unknown error"); 5546 return (sys_errlist[errnum]); 5547 } 5548