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 if (pread(fd, p, hdr.dirlistlen + 1, 1828 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1829 p[hdr.dirlistlen] != '\0') { 1830 free(p); 1831 goto cleanup1; 1832 } 1833 hints = p; 1834 close(fd); 1835 } 1836 1837 /* 1838 * If caller agreed to receive list which includes the default 1839 * paths, we are done. Otherwise, if we still did not 1840 * calculated filtered result, do it now. 1841 */ 1842 if (!nostdlib) 1843 return (hints[0] != '\0' ? hints : NULL); 1844 if (filtered_path != NULL) 1845 goto filt_ret; 1846 1847 /* 1848 * Obtain the list of all configured search paths, and the 1849 * list of the default paths. 1850 * 1851 * First estimate the size of the results. 1852 */ 1853 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1854 smeta.dls_cnt = 0; 1855 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1856 hmeta.dls_cnt = 0; 1857 1858 sargs.request = RTLD_DI_SERINFOSIZE; 1859 sargs.serinfo = &smeta; 1860 hargs.request = RTLD_DI_SERINFOSIZE; 1861 hargs.serinfo = &hmeta; 1862 1863 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1864 path_enumerate(hints, fill_search_info, &hargs); 1865 1866 SLPinfo = xmalloc(smeta.dls_size); 1867 hintinfo = xmalloc(hmeta.dls_size); 1868 1869 /* 1870 * Next fetch both sets of paths. 1871 */ 1872 sargs.request = RTLD_DI_SERINFO; 1873 sargs.serinfo = SLPinfo; 1874 sargs.serpath = &SLPinfo->dls_serpath[0]; 1875 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1876 1877 hargs.request = RTLD_DI_SERINFO; 1878 hargs.serinfo = hintinfo; 1879 hargs.serpath = &hintinfo->dls_serpath[0]; 1880 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1881 1882 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1883 path_enumerate(hints, fill_search_info, &hargs); 1884 1885 /* 1886 * Now calculate the difference between two sets, by excluding 1887 * standard paths from the full set. 1888 */ 1889 fndx = 0; 1890 fcount = 0; 1891 filtered_path = xmalloc(hdr.dirlistlen + 1); 1892 hintpath = &hintinfo->dls_serpath[0]; 1893 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1894 skip = false; 1895 SLPpath = &SLPinfo->dls_serpath[0]; 1896 /* 1897 * Check each standard path against current. 1898 */ 1899 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1900 /* matched, skip the path */ 1901 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1902 skip = true; 1903 break; 1904 } 1905 } 1906 if (skip) 1907 continue; 1908 /* 1909 * Not matched against any standard path, add the path 1910 * to result. Separate consequtive paths with ':'. 1911 */ 1912 if (fcount > 0) { 1913 filtered_path[fndx] = ':'; 1914 fndx++; 1915 } 1916 fcount++; 1917 flen = strlen(hintpath->dls_name); 1918 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1919 fndx += flen; 1920 } 1921 filtered_path[fndx] = '\0'; 1922 1923 free(SLPinfo); 1924 free(hintinfo); 1925 1926 filt_ret: 1927 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1928 } 1929 1930 static void 1931 init_dag(Obj_Entry *root) 1932 { 1933 const Needed_Entry *needed; 1934 const Objlist_Entry *elm; 1935 DoneList donelist; 1936 1937 if (root->dag_inited) 1938 return; 1939 donelist_init(&donelist); 1940 1941 /* Root object belongs to own DAG. */ 1942 objlist_push_tail(&root->dldags, root); 1943 objlist_push_tail(&root->dagmembers, root); 1944 donelist_check(&donelist, root); 1945 1946 /* 1947 * Add dependencies of root object to DAG in breadth order 1948 * by exploiting the fact that each new object get added 1949 * to the tail of the dagmembers list. 1950 */ 1951 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1952 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1953 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1954 continue; 1955 objlist_push_tail(&needed->obj->dldags, root); 1956 objlist_push_tail(&root->dagmembers, needed->obj); 1957 } 1958 } 1959 root->dag_inited = true; 1960 } 1961 1962 static void 1963 init_marker(Obj_Entry *marker) 1964 { 1965 1966 bzero(marker, sizeof(*marker)); 1967 marker->marker = true; 1968 } 1969 1970 Obj_Entry * 1971 globallist_curr(const Obj_Entry *obj) 1972 { 1973 1974 for (;;) { 1975 if (obj == NULL) 1976 return (NULL); 1977 if (!obj->marker) 1978 return (__DECONST(Obj_Entry *, obj)); 1979 obj = TAILQ_PREV(obj, obj_entry_q, next); 1980 } 1981 } 1982 1983 Obj_Entry * 1984 globallist_next(const Obj_Entry *obj) 1985 { 1986 1987 for (;;) { 1988 obj = TAILQ_NEXT(obj, next); 1989 if (obj == NULL) 1990 return (NULL); 1991 if (!obj->marker) 1992 return (__DECONST(Obj_Entry *, obj)); 1993 } 1994 } 1995 1996 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1997 static void 1998 hold_object(Obj_Entry *obj) 1999 { 2000 2001 obj->holdcount++; 2002 } 2003 2004 static void 2005 unhold_object(Obj_Entry *obj) 2006 { 2007 2008 assert(obj->holdcount > 0); 2009 if (--obj->holdcount == 0 && obj->unholdfree) 2010 release_object(obj); 2011 } 2012 2013 static void 2014 process_z(Obj_Entry *root) 2015 { 2016 const Objlist_Entry *elm; 2017 Obj_Entry *obj; 2018 2019 /* 2020 * Walk over object DAG and process every dependent object 2021 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2022 * to grow their own DAG. 2023 * 2024 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2025 * symlook_global() to work. 2026 * 2027 * For DF_1_NODELETE, the DAG should have its reference upped. 2028 */ 2029 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2030 obj = elm->obj; 2031 if (obj == NULL) 2032 continue; 2033 if (obj->z_nodelete && !obj->ref_nodel) { 2034 dbg("obj %s -z nodelete", obj->path); 2035 init_dag(obj); 2036 ref_dag(obj); 2037 obj->ref_nodel = true; 2038 } 2039 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2040 dbg("obj %s -z global", obj->path); 2041 objlist_push_tail(&list_global, obj); 2042 init_dag(obj); 2043 } 2044 } 2045 } 2046 /* 2047 * Initialize the dynamic linker. The argument is the address at which 2048 * the dynamic linker has been mapped into memory. The primary task of 2049 * this function is to relocate the dynamic linker. 2050 */ 2051 static void 2052 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2053 { 2054 Obj_Entry objtmp; /* Temporary rtld object */ 2055 const Elf_Ehdr *ehdr; 2056 const Elf_Dyn *dyn_rpath; 2057 const Elf_Dyn *dyn_soname; 2058 const Elf_Dyn *dyn_runpath; 2059 2060 #ifdef RTLD_INIT_PAGESIZES_EARLY 2061 /* The page size is required by the dynamic memory allocator. */ 2062 init_pagesizes(aux_info); 2063 #endif 2064 2065 /* 2066 * Conjure up an Obj_Entry structure for the dynamic linker. 2067 * 2068 * The "path" member can't be initialized yet because string constants 2069 * cannot yet be accessed. Below we will set it correctly. 2070 */ 2071 memset(&objtmp, 0, sizeof(objtmp)); 2072 objtmp.path = NULL; 2073 objtmp.rtld = true; 2074 objtmp.mapbase = mapbase; 2075 #ifdef PIC 2076 objtmp.relocbase = mapbase; 2077 #endif 2078 2079 objtmp.dynamic = rtld_dynamic(&objtmp); 2080 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2081 assert(objtmp.needed == NULL); 2082 #if !defined(__mips__) 2083 /* MIPS has a bogus DT_TEXTREL. */ 2084 assert(!objtmp.textrel); 2085 #endif 2086 /* 2087 * Temporarily put the dynamic linker entry into the object list, so 2088 * that symbols can be found. 2089 */ 2090 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2091 2092 ehdr = (Elf_Ehdr *)mapbase; 2093 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2094 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2095 2096 /* Initialize the object list. */ 2097 TAILQ_INIT(&obj_list); 2098 2099 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2100 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2101 2102 #ifndef RTLD_INIT_PAGESIZES_EARLY 2103 /* The page size is required by the dynamic memory allocator. */ 2104 init_pagesizes(aux_info); 2105 #endif 2106 2107 if (aux_info[AT_OSRELDATE] != NULL) 2108 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2109 2110 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2111 2112 /* Replace the path with a dynamically allocated copy. */ 2113 obj_rtld.path = xstrdup(ld_path_rtld); 2114 2115 r_debug.r_brk = r_debug_state; 2116 r_debug.r_state = RT_CONSISTENT; 2117 } 2118 2119 /* 2120 * Retrieve the array of supported page sizes. The kernel provides the page 2121 * sizes in increasing order. 2122 */ 2123 static void 2124 init_pagesizes(Elf_Auxinfo **aux_info) 2125 { 2126 static size_t psa[MAXPAGESIZES]; 2127 int mib[2]; 2128 size_t len, size; 2129 2130 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2131 NULL) { 2132 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2133 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2134 } else { 2135 len = 2; 2136 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2137 size = sizeof(psa); 2138 else { 2139 /* As a fallback, retrieve the base page size. */ 2140 size = sizeof(psa[0]); 2141 if (aux_info[AT_PAGESZ] != NULL) { 2142 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2143 goto psa_filled; 2144 } else { 2145 mib[0] = CTL_HW; 2146 mib[1] = HW_PAGESIZE; 2147 len = 2; 2148 } 2149 } 2150 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2151 _rtld_error("sysctl for hw.pagesize(s) failed"); 2152 rtld_die(); 2153 } 2154 psa_filled: 2155 pagesizes = psa; 2156 } 2157 npagesizes = size / sizeof(pagesizes[0]); 2158 /* Discard any invalid entries at the end of the array. */ 2159 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2160 npagesizes--; 2161 } 2162 2163 /* 2164 * Add the init functions from a needed object list (and its recursive 2165 * needed objects) to "list". This is not used directly; it is a helper 2166 * function for initlist_add_objects(). The write lock must be held 2167 * when this function is called. 2168 */ 2169 static void 2170 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2171 { 2172 /* Recursively process the successor needed objects. */ 2173 if (needed->next != NULL) 2174 initlist_add_neededs(needed->next, list); 2175 2176 /* Process the current needed object. */ 2177 if (needed->obj != NULL) 2178 initlist_add_objects(needed->obj, needed->obj, list); 2179 } 2180 2181 /* 2182 * Scan all of the DAGs rooted in the range of objects from "obj" to 2183 * "tail" and add their init functions to "list". This recurses over 2184 * the DAGs and ensure the proper init ordering such that each object's 2185 * needed libraries are initialized before the object itself. At the 2186 * same time, this function adds the objects to the global finalization 2187 * list "list_fini" in the opposite order. The write lock must be 2188 * held when this function is called. 2189 */ 2190 static void 2191 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2192 { 2193 Obj_Entry *nobj; 2194 2195 if (obj->init_scanned || obj->init_done) 2196 return; 2197 obj->init_scanned = true; 2198 2199 /* Recursively process the successor objects. */ 2200 nobj = globallist_next(obj); 2201 if (nobj != NULL && obj != tail) 2202 initlist_add_objects(nobj, tail, list); 2203 2204 /* Recursively process the needed objects. */ 2205 if (obj->needed != NULL) 2206 initlist_add_neededs(obj->needed, list); 2207 if (obj->needed_filtees != NULL) 2208 initlist_add_neededs(obj->needed_filtees, list); 2209 if (obj->needed_aux_filtees != NULL) 2210 initlist_add_neededs(obj->needed_aux_filtees, list); 2211 2212 /* Add the object to the init list. */ 2213 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2214 obj->init_array != (Elf_Addr)NULL) 2215 objlist_push_tail(list, obj); 2216 2217 /* Add the object to the global fini list in the reverse order. */ 2218 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2219 && !obj->on_fini_list) { 2220 objlist_push_head(&list_fini, obj); 2221 obj->on_fini_list = true; 2222 } 2223 } 2224 2225 #ifndef FPTR_TARGET 2226 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2227 #endif 2228 2229 static void 2230 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2231 { 2232 Needed_Entry *needed, *needed1; 2233 2234 for (needed = n; needed != NULL; needed = needed->next) { 2235 if (needed->obj != NULL) { 2236 dlclose_locked(needed->obj, lockstate); 2237 needed->obj = NULL; 2238 } 2239 } 2240 for (needed = n; needed != NULL; needed = needed1) { 2241 needed1 = needed->next; 2242 free(needed); 2243 } 2244 } 2245 2246 static void 2247 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2248 { 2249 2250 free_needed_filtees(obj->needed_filtees, lockstate); 2251 obj->needed_filtees = NULL; 2252 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2253 obj->needed_aux_filtees = NULL; 2254 obj->filtees_loaded = false; 2255 } 2256 2257 static void 2258 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2259 RtldLockState *lockstate) 2260 { 2261 2262 for (; needed != NULL; needed = needed->next) { 2263 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2264 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2265 RTLD_LOCAL, lockstate); 2266 } 2267 } 2268 2269 static void 2270 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2271 { 2272 2273 lock_restart_for_upgrade(lockstate); 2274 if (!obj->filtees_loaded) { 2275 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2276 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2277 obj->filtees_loaded = true; 2278 } 2279 } 2280 2281 static int 2282 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2283 { 2284 Obj_Entry *obj1; 2285 2286 for (; needed != NULL; needed = needed->next) { 2287 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2288 flags & ~RTLD_LO_NOLOAD); 2289 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2290 return (-1); 2291 } 2292 return (0); 2293 } 2294 2295 /* 2296 * Given a shared object, traverse its list of needed objects, and load 2297 * each of them. Returns 0 on success. Generates an error message and 2298 * returns -1 on failure. 2299 */ 2300 static int 2301 load_needed_objects(Obj_Entry *first, int flags) 2302 { 2303 Obj_Entry *obj; 2304 2305 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2306 if (obj->marker) 2307 continue; 2308 if (process_needed(obj, obj->needed, flags) == -1) 2309 return (-1); 2310 } 2311 return (0); 2312 } 2313 2314 static int 2315 load_preload_objects(void) 2316 { 2317 char *p = ld_preload; 2318 Obj_Entry *obj; 2319 static const char delim[] = " \t:;"; 2320 2321 if (p == NULL) 2322 return 0; 2323 2324 p += strspn(p, delim); 2325 while (*p != '\0') { 2326 size_t len = strcspn(p, delim); 2327 char savech; 2328 2329 savech = p[len]; 2330 p[len] = '\0'; 2331 obj = load_object(p, -1, NULL, 0); 2332 if (obj == NULL) 2333 return -1; /* XXX - cleanup */ 2334 obj->z_interpose = true; 2335 p[len] = savech; 2336 p += len; 2337 p += strspn(p, delim); 2338 } 2339 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2340 return 0; 2341 } 2342 2343 static const char * 2344 printable_path(const char *path) 2345 { 2346 2347 return (path == NULL ? "<unknown>" : path); 2348 } 2349 2350 /* 2351 * Load a shared object into memory, if it is not already loaded. The 2352 * object may be specified by name or by user-supplied file descriptor 2353 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2354 * duplicate is. 2355 * 2356 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2357 * on failure. 2358 */ 2359 static Obj_Entry * 2360 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2361 { 2362 Obj_Entry *obj; 2363 int fd; 2364 struct stat sb; 2365 char *path; 2366 2367 fd = -1; 2368 if (name != NULL) { 2369 TAILQ_FOREACH(obj, &obj_list, next) { 2370 if (obj->marker || obj->doomed) 2371 continue; 2372 if (object_match_name(obj, name)) 2373 return (obj); 2374 } 2375 2376 path = find_library(name, refobj, &fd); 2377 if (path == NULL) 2378 return (NULL); 2379 } else 2380 path = NULL; 2381 2382 if (fd >= 0) { 2383 /* 2384 * search_library_pathfds() opens a fresh file descriptor for the 2385 * library, so there is no need to dup(). 2386 */ 2387 } else if (fd_u == -1) { 2388 /* 2389 * If we didn't find a match by pathname, or the name is not 2390 * supplied, open the file and check again by device and inode. 2391 * This avoids false mismatches caused by multiple links or ".." 2392 * in pathnames. 2393 * 2394 * To avoid a race, we open the file and use fstat() rather than 2395 * using stat(). 2396 */ 2397 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2398 _rtld_error("Cannot open \"%s\"", path); 2399 free(path); 2400 return (NULL); 2401 } 2402 } else { 2403 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2404 if (fd == -1) { 2405 _rtld_error("Cannot dup fd"); 2406 free(path); 2407 return (NULL); 2408 } 2409 } 2410 if (fstat(fd, &sb) == -1) { 2411 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2412 close(fd); 2413 free(path); 2414 return NULL; 2415 } 2416 TAILQ_FOREACH(obj, &obj_list, next) { 2417 if (obj->marker || obj->doomed) 2418 continue; 2419 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2420 break; 2421 } 2422 if (obj != NULL && name != NULL) { 2423 object_add_name(obj, name); 2424 free(path); 2425 close(fd); 2426 return obj; 2427 } 2428 if (flags & RTLD_LO_NOLOAD) { 2429 free(path); 2430 close(fd); 2431 return (NULL); 2432 } 2433 2434 /* First use of this object, so we must map it in */ 2435 obj = do_load_object(fd, name, path, &sb, flags); 2436 if (obj == NULL) 2437 free(path); 2438 close(fd); 2439 2440 return obj; 2441 } 2442 2443 static Obj_Entry * 2444 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2445 int flags) 2446 { 2447 Obj_Entry *obj; 2448 struct statfs fs; 2449 2450 /* 2451 * but first, make sure that environment variables haven't been 2452 * used to circumvent the noexec flag on a filesystem. 2453 */ 2454 if (dangerous_ld_env) { 2455 if (fstatfs(fd, &fs) != 0) { 2456 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2457 return NULL; 2458 } 2459 if (fs.f_flags & MNT_NOEXEC) { 2460 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2461 return NULL; 2462 } 2463 } 2464 dbg("loading \"%s\"", printable_path(path)); 2465 obj = map_object(fd, printable_path(path), sbp); 2466 if (obj == NULL) 2467 return NULL; 2468 2469 /* 2470 * If DT_SONAME is present in the object, digest_dynamic2 already 2471 * added it to the object names. 2472 */ 2473 if (name != NULL) 2474 object_add_name(obj, name); 2475 obj->path = path; 2476 digest_dynamic(obj, 0); 2477 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2478 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2479 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2480 RTLD_LO_DLOPEN) { 2481 dbg("refusing to load non-loadable \"%s\"", obj->path); 2482 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2483 munmap(obj->mapbase, obj->mapsize); 2484 obj_free(obj); 2485 return (NULL); 2486 } 2487 2488 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2489 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2490 obj_count++; 2491 obj_loads++; 2492 linkmap_add(obj); /* for GDB & dlinfo() */ 2493 max_stack_flags |= obj->stack_flags; 2494 2495 dbg(" %p .. %p: %s", obj->mapbase, 2496 obj->mapbase + obj->mapsize - 1, obj->path); 2497 if (obj->textrel) 2498 dbg(" WARNING: %s has impure text", obj->path); 2499 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2500 obj->path); 2501 2502 return obj; 2503 } 2504 2505 static Obj_Entry * 2506 obj_from_addr(const void *addr) 2507 { 2508 Obj_Entry *obj; 2509 2510 TAILQ_FOREACH(obj, &obj_list, next) { 2511 if (obj->marker) 2512 continue; 2513 if (addr < (void *) obj->mapbase) 2514 continue; 2515 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2516 return obj; 2517 } 2518 return NULL; 2519 } 2520 2521 static void 2522 preinit_main(void) 2523 { 2524 Elf_Addr *preinit_addr; 2525 int index; 2526 2527 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2528 if (preinit_addr == NULL) 2529 return; 2530 2531 for (index = 0; index < obj_main->preinit_array_num; index++) { 2532 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2533 dbg("calling preinit function for %s at %p", obj_main->path, 2534 (void *)preinit_addr[index]); 2535 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2536 0, 0, obj_main->path); 2537 call_init_pointer(obj_main, preinit_addr[index]); 2538 } 2539 } 2540 } 2541 2542 /* 2543 * Call the finalization functions for each of the objects in "list" 2544 * belonging to the DAG of "root" and referenced once. If NULL "root" 2545 * is specified, every finalization function will be called regardless 2546 * of the reference count and the list elements won't be freed. All of 2547 * the objects are expected to have non-NULL fini functions. 2548 */ 2549 static void 2550 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2551 { 2552 Objlist_Entry *elm; 2553 char *saved_msg; 2554 Elf_Addr *fini_addr; 2555 int index; 2556 2557 assert(root == NULL || root->refcount == 1); 2558 2559 if (root != NULL) 2560 root->doomed = true; 2561 2562 /* 2563 * Preserve the current error message since a fini function might 2564 * call into the dynamic linker and overwrite it. 2565 */ 2566 saved_msg = errmsg_save(); 2567 do { 2568 STAILQ_FOREACH(elm, list, link) { 2569 if (root != NULL && (elm->obj->refcount != 1 || 2570 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2571 continue; 2572 /* Remove object from fini list to prevent recursive invocation. */ 2573 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2574 /* Ensure that new references cannot be acquired. */ 2575 elm->obj->doomed = true; 2576 2577 hold_object(elm->obj); 2578 lock_release(rtld_bind_lock, lockstate); 2579 /* 2580 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2581 * When this happens, DT_FINI_ARRAY is processed first. 2582 */ 2583 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2584 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2585 for (index = elm->obj->fini_array_num - 1; index >= 0; 2586 index--) { 2587 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2588 dbg("calling fini function for %s at %p", 2589 elm->obj->path, (void *)fini_addr[index]); 2590 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2591 (void *)fini_addr[index], 0, 0, elm->obj->path); 2592 call_initfini_pointer(elm->obj, fini_addr[index]); 2593 } 2594 } 2595 } 2596 if (elm->obj->fini != (Elf_Addr)NULL) { 2597 dbg("calling fini function for %s at %p", elm->obj->path, 2598 (void *)elm->obj->fini); 2599 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2600 0, 0, elm->obj->path); 2601 call_initfini_pointer(elm->obj, elm->obj->fini); 2602 } 2603 wlock_acquire(rtld_bind_lock, lockstate); 2604 unhold_object(elm->obj); 2605 /* No need to free anything if process is going down. */ 2606 if (root != NULL) 2607 free(elm); 2608 /* 2609 * We must restart the list traversal after every fini call 2610 * because a dlclose() call from the fini function or from 2611 * another thread might have modified the reference counts. 2612 */ 2613 break; 2614 } 2615 } while (elm != NULL); 2616 errmsg_restore(saved_msg); 2617 } 2618 2619 /* 2620 * Call the initialization functions for each of the objects in 2621 * "list". All of the objects are expected to have non-NULL init 2622 * functions. 2623 */ 2624 static void 2625 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2626 { 2627 Objlist_Entry *elm; 2628 Obj_Entry *obj; 2629 char *saved_msg; 2630 Elf_Addr *init_addr; 2631 int index; 2632 2633 /* 2634 * Clean init_scanned flag so that objects can be rechecked and 2635 * possibly initialized earlier if any of vectors called below 2636 * cause the change by using dlopen. 2637 */ 2638 TAILQ_FOREACH(obj, &obj_list, next) { 2639 if (obj->marker) 2640 continue; 2641 obj->init_scanned = false; 2642 } 2643 2644 /* 2645 * Preserve the current error message since an init function might 2646 * call into the dynamic linker and overwrite it. 2647 */ 2648 saved_msg = errmsg_save(); 2649 STAILQ_FOREACH(elm, list, link) { 2650 if (elm->obj->init_done) /* Initialized early. */ 2651 continue; 2652 /* 2653 * Race: other thread might try to use this object before current 2654 * one completes the initialization. Not much can be done here 2655 * without better locking. 2656 */ 2657 elm->obj->init_done = true; 2658 hold_object(elm->obj); 2659 lock_release(rtld_bind_lock, lockstate); 2660 2661 /* 2662 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2663 * When this happens, DT_INIT is processed first. 2664 */ 2665 if (elm->obj->init != (Elf_Addr)NULL) { 2666 dbg("calling init function for %s at %p", elm->obj->path, 2667 (void *)elm->obj->init); 2668 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2669 0, 0, elm->obj->path); 2670 call_initfini_pointer(elm->obj, elm->obj->init); 2671 } 2672 init_addr = (Elf_Addr *)elm->obj->init_array; 2673 if (init_addr != NULL) { 2674 for (index = 0; index < elm->obj->init_array_num; index++) { 2675 if (init_addr[index] != 0 && init_addr[index] != 1) { 2676 dbg("calling init function for %s at %p", elm->obj->path, 2677 (void *)init_addr[index]); 2678 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2679 (void *)init_addr[index], 0, 0, elm->obj->path); 2680 call_init_pointer(elm->obj, init_addr[index]); 2681 } 2682 } 2683 } 2684 wlock_acquire(rtld_bind_lock, lockstate); 2685 unhold_object(elm->obj); 2686 } 2687 errmsg_restore(saved_msg); 2688 } 2689 2690 static void 2691 objlist_clear(Objlist *list) 2692 { 2693 Objlist_Entry *elm; 2694 2695 while (!STAILQ_EMPTY(list)) { 2696 elm = STAILQ_FIRST(list); 2697 STAILQ_REMOVE_HEAD(list, link); 2698 free(elm); 2699 } 2700 } 2701 2702 static Objlist_Entry * 2703 objlist_find(Objlist *list, const Obj_Entry *obj) 2704 { 2705 Objlist_Entry *elm; 2706 2707 STAILQ_FOREACH(elm, list, link) 2708 if (elm->obj == obj) 2709 return elm; 2710 return NULL; 2711 } 2712 2713 static void 2714 objlist_init(Objlist *list) 2715 { 2716 STAILQ_INIT(list); 2717 } 2718 2719 static void 2720 objlist_push_head(Objlist *list, Obj_Entry *obj) 2721 { 2722 Objlist_Entry *elm; 2723 2724 elm = NEW(Objlist_Entry); 2725 elm->obj = obj; 2726 STAILQ_INSERT_HEAD(list, elm, link); 2727 } 2728 2729 static void 2730 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2731 { 2732 Objlist_Entry *elm; 2733 2734 elm = NEW(Objlist_Entry); 2735 elm->obj = obj; 2736 STAILQ_INSERT_TAIL(list, elm, link); 2737 } 2738 2739 static void 2740 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2741 { 2742 Objlist_Entry *elm, *listelm; 2743 2744 STAILQ_FOREACH(listelm, list, link) { 2745 if (listelm->obj == listobj) 2746 break; 2747 } 2748 elm = NEW(Objlist_Entry); 2749 elm->obj = obj; 2750 if (listelm != NULL) 2751 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2752 else 2753 STAILQ_INSERT_TAIL(list, elm, link); 2754 } 2755 2756 static void 2757 objlist_remove(Objlist *list, Obj_Entry *obj) 2758 { 2759 Objlist_Entry *elm; 2760 2761 if ((elm = objlist_find(list, obj)) != NULL) { 2762 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2763 free(elm); 2764 } 2765 } 2766 2767 /* 2768 * Relocate dag rooted in the specified object. 2769 * Returns 0 on success, or -1 on failure. 2770 */ 2771 2772 static int 2773 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2774 int flags, RtldLockState *lockstate) 2775 { 2776 Objlist_Entry *elm; 2777 int error; 2778 2779 error = 0; 2780 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2781 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2782 lockstate); 2783 if (error == -1) 2784 break; 2785 } 2786 return (error); 2787 } 2788 2789 /* 2790 * Prepare for, or clean after, relocating an object marked with 2791 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2792 * segments are remapped read-write. After relocations are done, the 2793 * segment's permissions are returned back to the modes specified in 2794 * the phdrs. If any relocation happened, or always for wired 2795 * program, COW is triggered. 2796 */ 2797 static int 2798 reloc_textrel_prot(Obj_Entry *obj, bool before) 2799 { 2800 const Elf_Phdr *ph; 2801 void *base; 2802 size_t l, sz; 2803 int prot; 2804 2805 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2806 l--, ph++) { 2807 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2808 continue; 2809 base = obj->relocbase + trunc_page(ph->p_vaddr); 2810 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2811 trunc_page(ph->p_vaddr); 2812 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2813 if (mprotect(base, sz, prot) == -1) { 2814 _rtld_error("%s: Cannot write-%sable text segment: %s", 2815 obj->path, before ? "en" : "dis", 2816 rtld_strerror(errno)); 2817 return (-1); 2818 } 2819 } 2820 return (0); 2821 } 2822 2823 /* 2824 * Relocate single object. 2825 * Returns 0 on success, or -1 on failure. 2826 */ 2827 static int 2828 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2829 int flags, RtldLockState *lockstate) 2830 { 2831 2832 if (obj->relocated) 2833 return (0); 2834 obj->relocated = true; 2835 if (obj != rtldobj) 2836 dbg("relocating \"%s\"", obj->path); 2837 2838 if (obj->symtab == NULL || obj->strtab == NULL || 2839 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2840 _rtld_error("%s: Shared object has no run-time symbol table", 2841 obj->path); 2842 return (-1); 2843 } 2844 2845 /* There are relocations to the write-protected text segment. */ 2846 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2847 return (-1); 2848 2849 /* Process the non-PLT non-IFUNC relocations. */ 2850 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2851 return (-1); 2852 2853 /* Re-protected the text segment. */ 2854 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2855 return (-1); 2856 2857 /* Set the special PLT or GOT entries. */ 2858 init_pltgot(obj); 2859 2860 /* Process the PLT relocations. */ 2861 if (reloc_plt(obj) == -1) 2862 return (-1); 2863 /* Relocate the jump slots if we are doing immediate binding. */ 2864 if (obj->bind_now || bind_now) 2865 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2866 return (-1); 2867 2868 /* 2869 * Process the non-PLT IFUNC relocations. The relocations are 2870 * processed in two phases, because IFUNC resolvers may 2871 * reference other symbols, which must be readily processed 2872 * before resolvers are called. 2873 */ 2874 if (obj->non_plt_gnu_ifunc && 2875 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2876 return (-1); 2877 2878 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2879 return (-1); 2880 2881 /* 2882 * Set up the magic number and version in the Obj_Entry. These 2883 * were checked in the crt1.o from the original ElfKit, so we 2884 * set them for backward compatibility. 2885 */ 2886 obj->magic = RTLD_MAGIC; 2887 obj->version = RTLD_VERSION; 2888 2889 return (0); 2890 } 2891 2892 /* 2893 * Relocate newly-loaded shared objects. The argument is a pointer to 2894 * the Obj_Entry for the first such object. All objects from the first 2895 * to the end of the list of objects are relocated. Returns 0 on success, 2896 * or -1 on failure. 2897 */ 2898 static int 2899 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2900 int flags, RtldLockState *lockstate) 2901 { 2902 Obj_Entry *obj; 2903 int error; 2904 2905 for (error = 0, obj = first; obj != NULL; 2906 obj = TAILQ_NEXT(obj, next)) { 2907 if (obj->marker) 2908 continue; 2909 error = relocate_object(obj, bind_now, rtldobj, flags, 2910 lockstate); 2911 if (error == -1) 2912 break; 2913 } 2914 return (error); 2915 } 2916 2917 /* 2918 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2919 * referencing STT_GNU_IFUNC symbols is postponed till the other 2920 * relocations are done. The indirect functions specified as 2921 * ifunc are allowed to call other symbols, so we need to have 2922 * objects relocated before asking for resolution from indirects. 2923 * 2924 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2925 * instead of the usual lazy handling of PLT slots. It is 2926 * consistent with how GNU does it. 2927 */ 2928 static int 2929 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2930 RtldLockState *lockstate) 2931 { 2932 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2933 return (-1); 2934 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2935 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2936 return (-1); 2937 return (0); 2938 } 2939 2940 static int 2941 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2942 RtldLockState *lockstate) 2943 { 2944 Obj_Entry *obj; 2945 2946 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2947 if (obj->marker) 2948 continue; 2949 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2950 return (-1); 2951 } 2952 return (0); 2953 } 2954 2955 static int 2956 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2957 RtldLockState *lockstate) 2958 { 2959 Objlist_Entry *elm; 2960 2961 STAILQ_FOREACH(elm, list, link) { 2962 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2963 lockstate) == -1) 2964 return (-1); 2965 } 2966 return (0); 2967 } 2968 2969 /* 2970 * Cleanup procedure. It will be called (by the atexit mechanism) just 2971 * before the process exits. 2972 */ 2973 static void 2974 rtld_exit(void) 2975 { 2976 RtldLockState lockstate; 2977 2978 wlock_acquire(rtld_bind_lock, &lockstate); 2979 dbg("rtld_exit()"); 2980 objlist_call_fini(&list_fini, NULL, &lockstate); 2981 /* No need to remove the items from the list, since we are exiting. */ 2982 if (!libmap_disable) 2983 lm_fini(); 2984 lock_release(rtld_bind_lock, &lockstate); 2985 } 2986 2987 /* 2988 * Iterate over a search path, translate each element, and invoke the 2989 * callback on the result. 2990 */ 2991 static void * 2992 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2993 { 2994 const char *trans; 2995 if (path == NULL) 2996 return (NULL); 2997 2998 path += strspn(path, ":;"); 2999 while (*path != '\0') { 3000 size_t len; 3001 char *res; 3002 3003 len = strcspn(path, ":;"); 3004 trans = lm_findn(NULL, path, len); 3005 if (trans) 3006 res = callback(trans, strlen(trans), arg); 3007 else 3008 res = callback(path, len, arg); 3009 3010 if (res != NULL) 3011 return (res); 3012 3013 path += len; 3014 path += strspn(path, ":;"); 3015 } 3016 3017 return (NULL); 3018 } 3019 3020 struct try_library_args { 3021 const char *name; 3022 size_t namelen; 3023 char *buffer; 3024 size_t buflen; 3025 }; 3026 3027 static void * 3028 try_library_path(const char *dir, size_t dirlen, void *param) 3029 { 3030 struct try_library_args *arg; 3031 3032 arg = param; 3033 if (*dir == '/' || trust) { 3034 char *pathname; 3035 3036 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3037 return (NULL); 3038 3039 pathname = arg->buffer; 3040 strncpy(pathname, dir, dirlen); 3041 pathname[dirlen] = '/'; 3042 strcpy(pathname + dirlen + 1, arg->name); 3043 3044 dbg(" Trying \"%s\"", pathname); 3045 if (access(pathname, F_OK) == 0) { /* We found it */ 3046 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3047 strcpy(pathname, arg->buffer); 3048 return (pathname); 3049 } 3050 } 3051 return (NULL); 3052 } 3053 3054 static char * 3055 search_library_path(const char *name, const char *path) 3056 { 3057 char *p; 3058 struct try_library_args arg; 3059 3060 if (path == NULL) 3061 return NULL; 3062 3063 arg.name = name; 3064 arg.namelen = strlen(name); 3065 arg.buffer = xmalloc(PATH_MAX); 3066 arg.buflen = PATH_MAX; 3067 3068 p = path_enumerate(path, try_library_path, &arg); 3069 3070 free(arg.buffer); 3071 3072 return (p); 3073 } 3074 3075 3076 /* 3077 * Finds the library with the given name using the directory descriptors 3078 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3079 * 3080 * Returns a freshly-opened close-on-exec file descriptor for the library, 3081 * or -1 if the library cannot be found. 3082 */ 3083 static char * 3084 search_library_pathfds(const char *name, const char *path, int *fdp) 3085 { 3086 char *envcopy, *fdstr, *found, *last_token; 3087 size_t len; 3088 int dirfd, fd; 3089 3090 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3091 3092 /* Don't load from user-specified libdirs into setuid binaries. */ 3093 if (!trust) 3094 return (NULL); 3095 3096 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3097 if (path == NULL) 3098 return (NULL); 3099 3100 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3101 if (name[0] == '/') { 3102 dbg("Absolute path (%s) passed to %s", name, __func__); 3103 return (NULL); 3104 } 3105 3106 /* 3107 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3108 * copy of the path, as strtok_r rewrites separator tokens 3109 * with '\0'. 3110 */ 3111 found = NULL; 3112 envcopy = xstrdup(path); 3113 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3114 fdstr = strtok_r(NULL, ":", &last_token)) { 3115 dirfd = parse_integer(fdstr); 3116 if (dirfd < 0) { 3117 _rtld_error("failed to parse directory FD: '%s'", 3118 fdstr); 3119 break; 3120 } 3121 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3122 if (fd >= 0) { 3123 *fdp = fd; 3124 len = strlen(fdstr) + strlen(name) + 3; 3125 found = xmalloc(len); 3126 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3127 _rtld_error("error generating '%d/%s'", 3128 dirfd, name); 3129 rtld_die(); 3130 } 3131 dbg("open('%s') => %d", found, fd); 3132 break; 3133 } 3134 } 3135 free(envcopy); 3136 3137 return (found); 3138 } 3139 3140 3141 int 3142 dlclose(void *handle) 3143 { 3144 RtldLockState lockstate; 3145 int error; 3146 3147 wlock_acquire(rtld_bind_lock, &lockstate); 3148 error = dlclose_locked(handle, &lockstate); 3149 lock_release(rtld_bind_lock, &lockstate); 3150 return (error); 3151 } 3152 3153 static int 3154 dlclose_locked(void *handle, RtldLockState *lockstate) 3155 { 3156 Obj_Entry *root; 3157 3158 root = dlcheck(handle); 3159 if (root == NULL) 3160 return -1; 3161 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3162 root->path); 3163 3164 /* Unreference the object and its dependencies. */ 3165 root->dl_refcount--; 3166 3167 if (root->refcount == 1) { 3168 /* 3169 * The object will be no longer referenced, so we must unload it. 3170 * First, call the fini functions. 3171 */ 3172 objlist_call_fini(&list_fini, root, lockstate); 3173 3174 unref_dag(root); 3175 3176 /* Finish cleaning up the newly-unreferenced objects. */ 3177 GDB_STATE(RT_DELETE,&root->linkmap); 3178 unload_object(root, lockstate); 3179 GDB_STATE(RT_CONSISTENT,NULL); 3180 } else 3181 unref_dag(root); 3182 3183 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3184 return 0; 3185 } 3186 3187 char * 3188 dlerror(void) 3189 { 3190 char *msg = error_message; 3191 error_message = NULL; 3192 return msg; 3193 } 3194 3195 /* 3196 * This function is deprecated and has no effect. 3197 */ 3198 void 3199 dllockinit(void *context, 3200 void *(*lock_create)(void *context), 3201 void (*rlock_acquire)(void *lock), 3202 void (*wlock_acquire)(void *lock), 3203 void (*lock_release)(void *lock), 3204 void (*lock_destroy)(void *lock), 3205 void (*context_destroy)(void *context)) 3206 { 3207 static void *cur_context; 3208 static void (*cur_context_destroy)(void *); 3209 3210 /* Just destroy the context from the previous call, if necessary. */ 3211 if (cur_context_destroy != NULL) 3212 cur_context_destroy(cur_context); 3213 cur_context = context; 3214 cur_context_destroy = context_destroy; 3215 } 3216 3217 void * 3218 dlopen(const char *name, int mode) 3219 { 3220 3221 return (rtld_dlopen(name, -1, mode)); 3222 } 3223 3224 void * 3225 fdlopen(int fd, int mode) 3226 { 3227 3228 return (rtld_dlopen(NULL, fd, mode)); 3229 } 3230 3231 static void * 3232 rtld_dlopen(const char *name, int fd, int mode) 3233 { 3234 RtldLockState lockstate; 3235 int lo_flags; 3236 3237 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3238 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3239 if (ld_tracing != NULL) { 3240 rlock_acquire(rtld_bind_lock, &lockstate); 3241 if (sigsetjmp(lockstate.env, 0) != 0) 3242 lock_upgrade(rtld_bind_lock, &lockstate); 3243 environ = (char **)*get_program_var_addr("environ", &lockstate); 3244 lock_release(rtld_bind_lock, &lockstate); 3245 } 3246 lo_flags = RTLD_LO_DLOPEN; 3247 if (mode & RTLD_NODELETE) 3248 lo_flags |= RTLD_LO_NODELETE; 3249 if (mode & RTLD_NOLOAD) 3250 lo_flags |= RTLD_LO_NOLOAD; 3251 if (ld_tracing != NULL) 3252 lo_flags |= RTLD_LO_TRACE; 3253 3254 return (dlopen_object(name, fd, obj_main, lo_flags, 3255 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3256 } 3257 3258 static void 3259 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3260 { 3261 3262 obj->dl_refcount--; 3263 unref_dag(obj); 3264 if (obj->refcount == 0) 3265 unload_object(obj, lockstate); 3266 } 3267 3268 static Obj_Entry * 3269 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3270 int mode, RtldLockState *lockstate) 3271 { 3272 Obj_Entry *old_obj_tail; 3273 Obj_Entry *obj; 3274 Objlist initlist; 3275 RtldLockState mlockstate; 3276 int result; 3277 3278 objlist_init(&initlist); 3279 3280 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3281 wlock_acquire(rtld_bind_lock, &mlockstate); 3282 lockstate = &mlockstate; 3283 } 3284 GDB_STATE(RT_ADD,NULL); 3285 3286 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3287 obj = NULL; 3288 if (name == NULL && fd == -1) { 3289 obj = obj_main; 3290 obj->refcount++; 3291 } else { 3292 obj = load_object(name, fd, refobj, lo_flags); 3293 } 3294 3295 if (obj) { 3296 obj->dl_refcount++; 3297 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3298 objlist_push_tail(&list_global, obj); 3299 if (globallist_next(old_obj_tail) != NULL) { 3300 /* We loaded something new. */ 3301 assert(globallist_next(old_obj_tail) == obj); 3302 result = load_needed_objects(obj, 3303 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3304 init_dag(obj); 3305 ref_dag(obj); 3306 if (result != -1) 3307 result = rtld_verify_versions(&obj->dagmembers); 3308 if (result != -1 && ld_tracing) 3309 goto trace; 3310 if (result == -1 || relocate_object_dag(obj, 3311 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3312 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3313 lockstate) == -1) { 3314 dlopen_cleanup(obj, lockstate); 3315 obj = NULL; 3316 } else if (lo_flags & RTLD_LO_EARLY) { 3317 /* 3318 * Do not call the init functions for early loaded 3319 * filtees. The image is still not initialized enough 3320 * for them to work. 3321 * 3322 * Our object is found by the global object list and 3323 * will be ordered among all init calls done right 3324 * before transferring control to main. 3325 */ 3326 } else { 3327 /* Make list of init functions to call. */ 3328 initlist_add_objects(obj, obj, &initlist); 3329 } 3330 /* 3331 * Process all no_delete or global objects here, given 3332 * them own DAGs to prevent their dependencies from being 3333 * unloaded. This has to be done after we have loaded all 3334 * of the dependencies, so that we do not miss any. 3335 */ 3336 if (obj != NULL) 3337 process_z(obj); 3338 } else { 3339 /* 3340 * Bump the reference counts for objects on this DAG. If 3341 * this is the first dlopen() call for the object that was 3342 * already loaded as a dependency, initialize the dag 3343 * starting at it. 3344 */ 3345 init_dag(obj); 3346 ref_dag(obj); 3347 3348 if ((lo_flags & RTLD_LO_TRACE) != 0) 3349 goto trace; 3350 } 3351 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3352 obj->z_nodelete) && !obj->ref_nodel) { 3353 dbg("obj %s nodelete", obj->path); 3354 ref_dag(obj); 3355 obj->z_nodelete = obj->ref_nodel = true; 3356 } 3357 } 3358 3359 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3360 name); 3361 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3362 3363 if (!(lo_flags & RTLD_LO_EARLY)) { 3364 map_stacks_exec(lockstate); 3365 } 3366 3367 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3368 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3369 lockstate) == -1) { 3370 objlist_clear(&initlist); 3371 dlopen_cleanup(obj, lockstate); 3372 if (lockstate == &mlockstate) 3373 lock_release(rtld_bind_lock, lockstate); 3374 return (NULL); 3375 } 3376 3377 if (!(lo_flags & RTLD_LO_EARLY)) { 3378 /* Call the init functions. */ 3379 objlist_call_init(&initlist, lockstate); 3380 } 3381 objlist_clear(&initlist); 3382 if (lockstate == &mlockstate) 3383 lock_release(rtld_bind_lock, lockstate); 3384 return obj; 3385 trace: 3386 trace_loaded_objects(obj); 3387 if (lockstate == &mlockstate) 3388 lock_release(rtld_bind_lock, lockstate); 3389 exit(0); 3390 } 3391 3392 static void * 3393 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3394 int flags) 3395 { 3396 DoneList donelist; 3397 const Obj_Entry *obj, *defobj; 3398 const Elf_Sym *def; 3399 SymLook req; 3400 RtldLockState lockstate; 3401 tls_index ti; 3402 void *sym; 3403 int res; 3404 3405 def = NULL; 3406 defobj = NULL; 3407 symlook_init(&req, name); 3408 req.ventry = ve; 3409 req.flags = flags | SYMLOOK_IN_PLT; 3410 req.lockstate = &lockstate; 3411 3412 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3413 rlock_acquire(rtld_bind_lock, &lockstate); 3414 if (sigsetjmp(lockstate.env, 0) != 0) 3415 lock_upgrade(rtld_bind_lock, &lockstate); 3416 if (handle == NULL || handle == RTLD_NEXT || 3417 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3418 3419 if ((obj = obj_from_addr(retaddr)) == NULL) { 3420 _rtld_error("Cannot determine caller's shared object"); 3421 lock_release(rtld_bind_lock, &lockstate); 3422 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3423 return NULL; 3424 } 3425 if (handle == NULL) { /* Just the caller's shared object. */ 3426 res = symlook_obj(&req, obj); 3427 if (res == 0) { 3428 def = req.sym_out; 3429 defobj = req.defobj_out; 3430 } 3431 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3432 handle == RTLD_SELF) { /* ... caller included */ 3433 if (handle == RTLD_NEXT) 3434 obj = globallist_next(obj); 3435 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3436 if (obj->marker) 3437 continue; 3438 res = symlook_obj(&req, obj); 3439 if (res == 0) { 3440 if (def == NULL || 3441 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3442 def = req.sym_out; 3443 defobj = req.defobj_out; 3444 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3445 break; 3446 } 3447 } 3448 } 3449 /* 3450 * Search the dynamic linker itself, and possibly resolve the 3451 * symbol from there. This is how the application links to 3452 * dynamic linker services such as dlopen. 3453 */ 3454 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3455 res = symlook_obj(&req, &obj_rtld); 3456 if (res == 0) { 3457 def = req.sym_out; 3458 defobj = req.defobj_out; 3459 } 3460 } 3461 } else { 3462 assert(handle == RTLD_DEFAULT); 3463 res = symlook_default(&req, obj); 3464 if (res == 0) { 3465 defobj = req.defobj_out; 3466 def = req.sym_out; 3467 } 3468 } 3469 } else { 3470 if ((obj = dlcheck(handle)) == NULL) { 3471 lock_release(rtld_bind_lock, &lockstate); 3472 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3473 return NULL; 3474 } 3475 3476 donelist_init(&donelist); 3477 if (obj->mainprog) { 3478 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3479 res = symlook_global(&req, &donelist); 3480 if (res == 0) { 3481 def = req.sym_out; 3482 defobj = req.defobj_out; 3483 } 3484 /* 3485 * Search the dynamic linker itself, and possibly resolve the 3486 * symbol from there. This is how the application links to 3487 * dynamic linker services such as dlopen. 3488 */ 3489 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3490 res = symlook_obj(&req, &obj_rtld); 3491 if (res == 0) { 3492 def = req.sym_out; 3493 defobj = req.defobj_out; 3494 } 3495 } 3496 } 3497 else { 3498 /* Search the whole DAG rooted at the given object. */ 3499 res = symlook_list(&req, &obj->dagmembers, &donelist); 3500 if (res == 0) { 3501 def = req.sym_out; 3502 defobj = req.defobj_out; 3503 } 3504 } 3505 } 3506 3507 if (def != NULL) { 3508 lock_release(rtld_bind_lock, &lockstate); 3509 3510 /* 3511 * The value required by the caller is derived from the value 3512 * of the symbol. this is simply the relocated value of the 3513 * symbol. 3514 */ 3515 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3516 sym = make_function_pointer(def, defobj); 3517 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3518 sym = rtld_resolve_ifunc(defobj, def); 3519 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3520 ti.ti_module = defobj->tlsindex; 3521 ti.ti_offset = def->st_value; 3522 sym = __tls_get_addr(&ti); 3523 } else 3524 sym = defobj->relocbase + def->st_value; 3525 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3526 return (sym); 3527 } 3528 3529 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3530 ve != NULL ? ve->name : ""); 3531 lock_release(rtld_bind_lock, &lockstate); 3532 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3533 return NULL; 3534 } 3535 3536 void * 3537 dlsym(void *handle, const char *name) 3538 { 3539 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3540 SYMLOOK_DLSYM); 3541 } 3542 3543 dlfunc_t 3544 dlfunc(void *handle, const char *name) 3545 { 3546 union { 3547 void *d; 3548 dlfunc_t f; 3549 } rv; 3550 3551 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3552 SYMLOOK_DLSYM); 3553 return (rv.f); 3554 } 3555 3556 void * 3557 dlvsym(void *handle, const char *name, const char *version) 3558 { 3559 Ver_Entry ventry; 3560 3561 ventry.name = version; 3562 ventry.file = NULL; 3563 ventry.hash = elf_hash(version); 3564 ventry.flags= 0; 3565 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3566 SYMLOOK_DLSYM); 3567 } 3568 3569 int 3570 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3571 { 3572 const Obj_Entry *obj; 3573 RtldLockState lockstate; 3574 3575 rlock_acquire(rtld_bind_lock, &lockstate); 3576 obj = obj_from_addr(addr); 3577 if (obj == NULL) { 3578 _rtld_error("No shared object contains address"); 3579 lock_release(rtld_bind_lock, &lockstate); 3580 return (0); 3581 } 3582 rtld_fill_dl_phdr_info(obj, phdr_info); 3583 lock_release(rtld_bind_lock, &lockstate); 3584 return (1); 3585 } 3586 3587 int 3588 dladdr(const void *addr, Dl_info *info) 3589 { 3590 const Obj_Entry *obj; 3591 const Elf_Sym *def; 3592 void *symbol_addr; 3593 unsigned long symoffset; 3594 RtldLockState lockstate; 3595 3596 rlock_acquire(rtld_bind_lock, &lockstate); 3597 obj = obj_from_addr(addr); 3598 if (obj == NULL) { 3599 _rtld_error("No shared object contains address"); 3600 lock_release(rtld_bind_lock, &lockstate); 3601 return 0; 3602 } 3603 info->dli_fname = obj->path; 3604 info->dli_fbase = obj->mapbase; 3605 info->dli_saddr = (void *)0; 3606 info->dli_sname = NULL; 3607 3608 /* 3609 * Walk the symbol list looking for the symbol whose address is 3610 * closest to the address sent in. 3611 */ 3612 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3613 def = obj->symtab + symoffset; 3614 3615 /* 3616 * For skip the symbol if st_shndx is either SHN_UNDEF or 3617 * SHN_COMMON. 3618 */ 3619 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3620 continue; 3621 3622 /* 3623 * If the symbol is greater than the specified address, or if it 3624 * is further away from addr than the current nearest symbol, 3625 * then reject it. 3626 */ 3627 symbol_addr = obj->relocbase + def->st_value; 3628 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3629 continue; 3630 3631 /* Update our idea of the nearest symbol. */ 3632 info->dli_sname = obj->strtab + def->st_name; 3633 info->dli_saddr = symbol_addr; 3634 3635 /* Exact match? */ 3636 if (info->dli_saddr == addr) 3637 break; 3638 } 3639 lock_release(rtld_bind_lock, &lockstate); 3640 return 1; 3641 } 3642 3643 int 3644 dlinfo(void *handle, int request, void *p) 3645 { 3646 const Obj_Entry *obj; 3647 RtldLockState lockstate; 3648 int error; 3649 3650 rlock_acquire(rtld_bind_lock, &lockstate); 3651 3652 if (handle == NULL || handle == RTLD_SELF) { 3653 void *retaddr; 3654 3655 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3656 if ((obj = obj_from_addr(retaddr)) == NULL) 3657 _rtld_error("Cannot determine caller's shared object"); 3658 } else 3659 obj = dlcheck(handle); 3660 3661 if (obj == NULL) { 3662 lock_release(rtld_bind_lock, &lockstate); 3663 return (-1); 3664 } 3665 3666 error = 0; 3667 switch (request) { 3668 case RTLD_DI_LINKMAP: 3669 *((struct link_map const **)p) = &obj->linkmap; 3670 break; 3671 case RTLD_DI_ORIGIN: 3672 error = rtld_dirname(obj->path, p); 3673 break; 3674 3675 case RTLD_DI_SERINFOSIZE: 3676 case RTLD_DI_SERINFO: 3677 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3678 break; 3679 3680 default: 3681 _rtld_error("Invalid request %d passed to dlinfo()", request); 3682 error = -1; 3683 } 3684 3685 lock_release(rtld_bind_lock, &lockstate); 3686 3687 return (error); 3688 } 3689 3690 static void 3691 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3692 { 3693 3694 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3695 phdr_info->dlpi_name = obj->path; 3696 phdr_info->dlpi_phdr = obj->phdr; 3697 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3698 phdr_info->dlpi_tls_modid = obj->tlsindex; 3699 phdr_info->dlpi_tls_data = obj->tlsinit; 3700 phdr_info->dlpi_adds = obj_loads; 3701 phdr_info->dlpi_subs = obj_loads - obj_count; 3702 } 3703 3704 int 3705 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3706 { 3707 struct dl_phdr_info phdr_info; 3708 Obj_Entry *obj, marker; 3709 RtldLockState bind_lockstate, phdr_lockstate; 3710 int error; 3711 3712 init_marker(&marker); 3713 error = 0; 3714 3715 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3716 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3717 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3718 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3719 rtld_fill_dl_phdr_info(obj, &phdr_info); 3720 hold_object(obj); 3721 lock_release(rtld_bind_lock, &bind_lockstate); 3722 3723 error = callback(&phdr_info, sizeof phdr_info, param); 3724 3725 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3726 unhold_object(obj); 3727 obj = globallist_next(&marker); 3728 TAILQ_REMOVE(&obj_list, &marker, next); 3729 if (error != 0) { 3730 lock_release(rtld_bind_lock, &bind_lockstate); 3731 lock_release(rtld_phdr_lock, &phdr_lockstate); 3732 return (error); 3733 } 3734 } 3735 3736 if (error == 0) { 3737 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3738 lock_release(rtld_bind_lock, &bind_lockstate); 3739 error = callback(&phdr_info, sizeof(phdr_info), param); 3740 } 3741 lock_release(rtld_phdr_lock, &phdr_lockstate); 3742 return (error); 3743 } 3744 3745 static void * 3746 fill_search_info(const char *dir, size_t dirlen, void *param) 3747 { 3748 struct fill_search_info_args *arg; 3749 3750 arg = param; 3751 3752 if (arg->request == RTLD_DI_SERINFOSIZE) { 3753 arg->serinfo->dls_cnt ++; 3754 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3755 } else { 3756 struct dl_serpath *s_entry; 3757 3758 s_entry = arg->serpath; 3759 s_entry->dls_name = arg->strspace; 3760 s_entry->dls_flags = arg->flags; 3761 3762 strncpy(arg->strspace, dir, dirlen); 3763 arg->strspace[dirlen] = '\0'; 3764 3765 arg->strspace += dirlen + 1; 3766 arg->serpath++; 3767 } 3768 3769 return (NULL); 3770 } 3771 3772 static int 3773 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3774 { 3775 struct dl_serinfo _info; 3776 struct fill_search_info_args args; 3777 3778 args.request = RTLD_DI_SERINFOSIZE; 3779 args.serinfo = &_info; 3780 3781 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3782 _info.dls_cnt = 0; 3783 3784 path_enumerate(obj->rpath, fill_search_info, &args); 3785 path_enumerate(ld_library_path, fill_search_info, &args); 3786 path_enumerate(obj->runpath, fill_search_info, &args); 3787 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3788 if (!obj->z_nodeflib) 3789 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3790 3791 3792 if (request == RTLD_DI_SERINFOSIZE) { 3793 info->dls_size = _info.dls_size; 3794 info->dls_cnt = _info.dls_cnt; 3795 return (0); 3796 } 3797 3798 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3799 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3800 return (-1); 3801 } 3802 3803 args.request = RTLD_DI_SERINFO; 3804 args.serinfo = info; 3805 args.serpath = &info->dls_serpath[0]; 3806 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3807 3808 args.flags = LA_SER_RUNPATH; 3809 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3810 return (-1); 3811 3812 args.flags = LA_SER_LIBPATH; 3813 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3814 return (-1); 3815 3816 args.flags = LA_SER_RUNPATH; 3817 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3818 return (-1); 3819 3820 args.flags = LA_SER_CONFIG; 3821 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3822 != NULL) 3823 return (-1); 3824 3825 args.flags = LA_SER_DEFAULT; 3826 if (!obj->z_nodeflib && 3827 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3828 return (-1); 3829 return (0); 3830 } 3831 3832 static int 3833 rtld_dirname(const char *path, char *bname) 3834 { 3835 const char *endp; 3836 3837 /* Empty or NULL string gets treated as "." */ 3838 if (path == NULL || *path == '\0') { 3839 bname[0] = '.'; 3840 bname[1] = '\0'; 3841 return (0); 3842 } 3843 3844 /* Strip trailing slashes */ 3845 endp = path + strlen(path) - 1; 3846 while (endp > path && *endp == '/') 3847 endp--; 3848 3849 /* Find the start of the dir */ 3850 while (endp > path && *endp != '/') 3851 endp--; 3852 3853 /* Either the dir is "/" or there are no slashes */ 3854 if (endp == path) { 3855 bname[0] = *endp == '/' ? '/' : '.'; 3856 bname[1] = '\0'; 3857 return (0); 3858 } else { 3859 do { 3860 endp--; 3861 } while (endp > path && *endp == '/'); 3862 } 3863 3864 if (endp - path + 2 > PATH_MAX) 3865 { 3866 _rtld_error("Filename is too long: %s", path); 3867 return(-1); 3868 } 3869 3870 strncpy(bname, path, endp - path + 1); 3871 bname[endp - path + 1] = '\0'; 3872 return (0); 3873 } 3874 3875 static int 3876 rtld_dirname_abs(const char *path, char *base) 3877 { 3878 char *last; 3879 3880 if (realpath(path, base) == NULL) 3881 return (-1); 3882 dbg("%s -> %s", path, base); 3883 last = strrchr(base, '/'); 3884 if (last == NULL) 3885 return (-1); 3886 if (last != base) 3887 *last = '\0'; 3888 return (0); 3889 } 3890 3891 static void 3892 linkmap_add(Obj_Entry *obj) 3893 { 3894 struct link_map *l = &obj->linkmap; 3895 struct link_map *prev; 3896 3897 obj->linkmap.l_name = obj->path; 3898 obj->linkmap.l_addr = obj->mapbase; 3899 obj->linkmap.l_ld = obj->dynamic; 3900 #ifdef __mips__ 3901 /* GDB needs load offset on MIPS to use the symbols */ 3902 obj->linkmap.l_offs = obj->relocbase; 3903 #endif 3904 3905 if (r_debug.r_map == NULL) { 3906 r_debug.r_map = l; 3907 return; 3908 } 3909 3910 /* 3911 * Scan to the end of the list, but not past the entry for the 3912 * dynamic linker, which we want to keep at the very end. 3913 */ 3914 for (prev = r_debug.r_map; 3915 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3916 prev = prev->l_next) 3917 ; 3918 3919 /* Link in the new entry. */ 3920 l->l_prev = prev; 3921 l->l_next = prev->l_next; 3922 if (l->l_next != NULL) 3923 l->l_next->l_prev = l; 3924 prev->l_next = l; 3925 } 3926 3927 static void 3928 linkmap_delete(Obj_Entry *obj) 3929 { 3930 struct link_map *l = &obj->linkmap; 3931 3932 if (l->l_prev == NULL) { 3933 if ((r_debug.r_map = l->l_next) != NULL) 3934 l->l_next->l_prev = NULL; 3935 return; 3936 } 3937 3938 if ((l->l_prev->l_next = l->l_next) != NULL) 3939 l->l_next->l_prev = l->l_prev; 3940 } 3941 3942 /* 3943 * Function for the debugger to set a breakpoint on to gain control. 3944 * 3945 * The two parameters allow the debugger to easily find and determine 3946 * what the runtime loader is doing and to whom it is doing it. 3947 * 3948 * When the loadhook trap is hit (r_debug_state, set at program 3949 * initialization), the arguments can be found on the stack: 3950 * 3951 * +8 struct link_map *m 3952 * +4 struct r_debug *rd 3953 * +0 RetAddr 3954 */ 3955 void 3956 r_debug_state(struct r_debug* rd, struct link_map *m) 3957 { 3958 /* 3959 * The following is a hack to force the compiler to emit calls to 3960 * this function, even when optimizing. If the function is empty, 3961 * the compiler is not obliged to emit any code for calls to it, 3962 * even when marked __noinline. However, gdb depends on those 3963 * calls being made. 3964 */ 3965 __compiler_membar(); 3966 } 3967 3968 /* 3969 * A function called after init routines have completed. This can be used to 3970 * break before a program's entry routine is called, and can be used when 3971 * main is not available in the symbol table. 3972 */ 3973 void 3974 _r_debug_postinit(struct link_map *m) 3975 { 3976 3977 /* See r_debug_state(). */ 3978 __compiler_membar(); 3979 } 3980 3981 static void 3982 release_object(Obj_Entry *obj) 3983 { 3984 3985 if (obj->holdcount > 0) { 3986 obj->unholdfree = true; 3987 return; 3988 } 3989 munmap(obj->mapbase, obj->mapsize); 3990 linkmap_delete(obj); 3991 obj_free(obj); 3992 } 3993 3994 /* 3995 * Get address of the pointer variable in the main program. 3996 * Prefer non-weak symbol over the weak one. 3997 */ 3998 static const void ** 3999 get_program_var_addr(const char *name, RtldLockState *lockstate) 4000 { 4001 SymLook req; 4002 DoneList donelist; 4003 4004 symlook_init(&req, name); 4005 req.lockstate = lockstate; 4006 donelist_init(&donelist); 4007 if (symlook_global(&req, &donelist) != 0) 4008 return (NULL); 4009 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4010 return ((const void **)make_function_pointer(req.sym_out, 4011 req.defobj_out)); 4012 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4013 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4014 else 4015 return ((const void **)(req.defobj_out->relocbase + 4016 req.sym_out->st_value)); 4017 } 4018 4019 /* 4020 * Set a pointer variable in the main program to the given value. This 4021 * is used to set key variables such as "environ" before any of the 4022 * init functions are called. 4023 */ 4024 static void 4025 set_program_var(const char *name, const void *value) 4026 { 4027 const void **addr; 4028 4029 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4030 dbg("\"%s\": *%p <-- %p", name, addr, value); 4031 *addr = value; 4032 } 4033 } 4034 4035 /* 4036 * Search the global objects, including dependencies and main object, 4037 * for the given symbol. 4038 */ 4039 static int 4040 symlook_global(SymLook *req, DoneList *donelist) 4041 { 4042 SymLook req1; 4043 const Objlist_Entry *elm; 4044 int res; 4045 4046 symlook_init_from_req(&req1, req); 4047 4048 /* Search all objects loaded at program start up. */ 4049 if (req->defobj_out == NULL || 4050 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4051 res = symlook_list(&req1, &list_main, donelist); 4052 if (res == 0 && (req->defobj_out == NULL || 4053 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4054 req->sym_out = req1.sym_out; 4055 req->defobj_out = req1.defobj_out; 4056 assert(req->defobj_out != NULL); 4057 } 4058 } 4059 4060 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4061 STAILQ_FOREACH(elm, &list_global, link) { 4062 if (req->defobj_out != NULL && 4063 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4064 break; 4065 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4066 if (res == 0 && (req->defobj_out == NULL || 4067 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4068 req->sym_out = req1.sym_out; 4069 req->defobj_out = req1.defobj_out; 4070 assert(req->defobj_out != NULL); 4071 } 4072 } 4073 4074 return (req->sym_out != NULL ? 0 : ESRCH); 4075 } 4076 4077 /* 4078 * Given a symbol name in a referencing object, find the corresponding 4079 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4080 * no definition was found. Returns a pointer to the Obj_Entry of the 4081 * defining object via the reference parameter DEFOBJ_OUT. 4082 */ 4083 static int 4084 symlook_default(SymLook *req, const Obj_Entry *refobj) 4085 { 4086 DoneList donelist; 4087 const Objlist_Entry *elm; 4088 SymLook req1; 4089 int res; 4090 4091 donelist_init(&donelist); 4092 symlook_init_from_req(&req1, req); 4093 4094 /* 4095 * Look first in the referencing object if linked symbolically, 4096 * and similarly handle protected symbols. 4097 */ 4098 res = symlook_obj(&req1, refobj); 4099 if (res == 0 && (refobj->symbolic || 4100 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4101 req->sym_out = req1.sym_out; 4102 req->defobj_out = req1.defobj_out; 4103 assert(req->defobj_out != NULL); 4104 } 4105 if (refobj->symbolic || req->defobj_out != NULL) 4106 donelist_check(&donelist, refobj); 4107 4108 symlook_global(req, &donelist); 4109 4110 /* Search all dlopened DAGs containing the referencing object. */ 4111 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4112 if (req->sym_out != NULL && 4113 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4114 break; 4115 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4116 if (res == 0 && (req->sym_out == NULL || 4117 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4118 req->sym_out = req1.sym_out; 4119 req->defobj_out = req1.defobj_out; 4120 assert(req->defobj_out != NULL); 4121 } 4122 } 4123 4124 /* 4125 * Search the dynamic linker itself, and possibly resolve the 4126 * symbol from there. This is how the application links to 4127 * dynamic linker services such as dlopen. 4128 */ 4129 if (req->sym_out == NULL || 4130 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4131 res = symlook_obj(&req1, &obj_rtld); 4132 if (res == 0) { 4133 req->sym_out = req1.sym_out; 4134 req->defobj_out = req1.defobj_out; 4135 assert(req->defobj_out != NULL); 4136 } 4137 } 4138 4139 return (req->sym_out != NULL ? 0 : ESRCH); 4140 } 4141 4142 static int 4143 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4144 { 4145 const Elf_Sym *def; 4146 const Obj_Entry *defobj; 4147 const Objlist_Entry *elm; 4148 SymLook req1; 4149 int res; 4150 4151 def = NULL; 4152 defobj = NULL; 4153 STAILQ_FOREACH(elm, objlist, link) { 4154 if (donelist_check(dlp, elm->obj)) 4155 continue; 4156 symlook_init_from_req(&req1, req); 4157 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4158 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4159 def = req1.sym_out; 4160 defobj = req1.defobj_out; 4161 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4162 break; 4163 } 4164 } 4165 } 4166 if (def != NULL) { 4167 req->sym_out = def; 4168 req->defobj_out = defobj; 4169 return (0); 4170 } 4171 return (ESRCH); 4172 } 4173 4174 /* 4175 * Search the chain of DAGS cointed to by the given Needed_Entry 4176 * for a symbol of the given name. Each DAG is scanned completely 4177 * before advancing to the next one. Returns a pointer to the symbol, 4178 * or NULL if no definition was found. 4179 */ 4180 static int 4181 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4182 { 4183 const Elf_Sym *def; 4184 const Needed_Entry *n; 4185 const Obj_Entry *defobj; 4186 SymLook req1; 4187 int res; 4188 4189 def = NULL; 4190 defobj = NULL; 4191 symlook_init_from_req(&req1, req); 4192 for (n = needed; n != NULL; n = n->next) { 4193 if (n->obj == NULL || 4194 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4195 continue; 4196 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4197 def = req1.sym_out; 4198 defobj = req1.defobj_out; 4199 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4200 break; 4201 } 4202 } 4203 if (def != NULL) { 4204 req->sym_out = def; 4205 req->defobj_out = defobj; 4206 return (0); 4207 } 4208 return (ESRCH); 4209 } 4210 4211 /* 4212 * Search the symbol table of a single shared object for a symbol of 4213 * the given name and version, if requested. Returns a pointer to the 4214 * symbol, or NULL if no definition was found. If the object is 4215 * filter, return filtered symbol from filtee. 4216 * 4217 * The symbol's hash value is passed in for efficiency reasons; that 4218 * eliminates many recomputations of the hash value. 4219 */ 4220 int 4221 symlook_obj(SymLook *req, const Obj_Entry *obj) 4222 { 4223 DoneList donelist; 4224 SymLook req1; 4225 int flags, res, mres; 4226 4227 /* 4228 * If there is at least one valid hash at this point, we prefer to 4229 * use the faster GNU version if available. 4230 */ 4231 if (obj->valid_hash_gnu) 4232 mres = symlook_obj1_gnu(req, obj); 4233 else if (obj->valid_hash_sysv) 4234 mres = symlook_obj1_sysv(req, obj); 4235 else 4236 return (EINVAL); 4237 4238 if (mres == 0) { 4239 if (obj->needed_filtees != NULL) { 4240 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4241 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4242 donelist_init(&donelist); 4243 symlook_init_from_req(&req1, req); 4244 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4245 if (res == 0) { 4246 req->sym_out = req1.sym_out; 4247 req->defobj_out = req1.defobj_out; 4248 } 4249 return (res); 4250 } 4251 if (obj->needed_aux_filtees != NULL) { 4252 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4253 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4254 donelist_init(&donelist); 4255 symlook_init_from_req(&req1, req); 4256 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4257 if (res == 0) { 4258 req->sym_out = req1.sym_out; 4259 req->defobj_out = req1.defobj_out; 4260 return (res); 4261 } 4262 } 4263 } 4264 return (mres); 4265 } 4266 4267 /* Symbol match routine common to both hash functions */ 4268 static bool 4269 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4270 const unsigned long symnum) 4271 { 4272 Elf_Versym verndx; 4273 const Elf_Sym *symp; 4274 const char *strp; 4275 4276 symp = obj->symtab + symnum; 4277 strp = obj->strtab + symp->st_name; 4278 4279 switch (ELF_ST_TYPE(symp->st_info)) { 4280 case STT_FUNC: 4281 case STT_NOTYPE: 4282 case STT_OBJECT: 4283 case STT_COMMON: 4284 case STT_GNU_IFUNC: 4285 if (symp->st_value == 0) 4286 return (false); 4287 /* fallthrough */ 4288 case STT_TLS: 4289 if (symp->st_shndx != SHN_UNDEF) 4290 break; 4291 #ifndef __mips__ 4292 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4293 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4294 break; 4295 /* fallthrough */ 4296 #endif 4297 default: 4298 return (false); 4299 } 4300 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4301 return (false); 4302 4303 if (req->ventry == NULL) { 4304 if (obj->versyms != NULL) { 4305 verndx = VER_NDX(obj->versyms[symnum]); 4306 if (verndx > obj->vernum) { 4307 _rtld_error( 4308 "%s: symbol %s references wrong version %d", 4309 obj->path, obj->strtab + symnum, verndx); 4310 return (false); 4311 } 4312 /* 4313 * If we are not called from dlsym (i.e. this 4314 * is a normal relocation from unversioned 4315 * binary), accept the symbol immediately if 4316 * it happens to have first version after this 4317 * shared object became versioned. Otherwise, 4318 * if symbol is versioned and not hidden, 4319 * remember it. If it is the only symbol with 4320 * this name exported by the shared object, it 4321 * will be returned as a match by the calling 4322 * function. If symbol is global (verndx < 2) 4323 * accept it unconditionally. 4324 */ 4325 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4326 verndx == VER_NDX_GIVEN) { 4327 result->sym_out = symp; 4328 return (true); 4329 } 4330 else if (verndx >= VER_NDX_GIVEN) { 4331 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4332 == 0) { 4333 if (result->vsymp == NULL) 4334 result->vsymp = symp; 4335 result->vcount++; 4336 } 4337 return (false); 4338 } 4339 } 4340 result->sym_out = symp; 4341 return (true); 4342 } 4343 if (obj->versyms == NULL) { 4344 if (object_match_name(obj, req->ventry->name)) { 4345 _rtld_error("%s: object %s should provide version %s " 4346 "for symbol %s", obj_rtld.path, obj->path, 4347 req->ventry->name, obj->strtab + symnum); 4348 return (false); 4349 } 4350 } else { 4351 verndx = VER_NDX(obj->versyms[symnum]); 4352 if (verndx > obj->vernum) { 4353 _rtld_error("%s: symbol %s references wrong version %d", 4354 obj->path, obj->strtab + symnum, verndx); 4355 return (false); 4356 } 4357 if (obj->vertab[verndx].hash != req->ventry->hash || 4358 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4359 /* 4360 * Version does not match. Look if this is a 4361 * global symbol and if it is not hidden. If 4362 * global symbol (verndx < 2) is available, 4363 * use it. Do not return symbol if we are 4364 * called by dlvsym, because dlvsym looks for 4365 * a specific version and default one is not 4366 * what dlvsym wants. 4367 */ 4368 if ((req->flags & SYMLOOK_DLSYM) || 4369 (verndx >= VER_NDX_GIVEN) || 4370 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4371 return (false); 4372 } 4373 } 4374 result->sym_out = symp; 4375 return (true); 4376 } 4377 4378 /* 4379 * Search for symbol using SysV hash function. 4380 * obj->buckets is known not to be NULL at this point; the test for this was 4381 * performed with the obj->valid_hash_sysv assignment. 4382 */ 4383 static int 4384 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4385 { 4386 unsigned long symnum; 4387 Sym_Match_Result matchres; 4388 4389 matchres.sym_out = NULL; 4390 matchres.vsymp = NULL; 4391 matchres.vcount = 0; 4392 4393 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4394 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4395 if (symnum >= obj->nchains) 4396 return (ESRCH); /* Bad object */ 4397 4398 if (matched_symbol(req, obj, &matchres, symnum)) { 4399 req->sym_out = matchres.sym_out; 4400 req->defobj_out = obj; 4401 return (0); 4402 } 4403 } 4404 if (matchres.vcount == 1) { 4405 req->sym_out = matchres.vsymp; 4406 req->defobj_out = obj; 4407 return (0); 4408 } 4409 return (ESRCH); 4410 } 4411 4412 /* Search for symbol using GNU hash function */ 4413 static int 4414 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4415 { 4416 Elf_Addr bloom_word; 4417 const Elf32_Word *hashval; 4418 Elf32_Word bucket; 4419 Sym_Match_Result matchres; 4420 unsigned int h1, h2; 4421 unsigned long symnum; 4422 4423 matchres.sym_out = NULL; 4424 matchres.vsymp = NULL; 4425 matchres.vcount = 0; 4426 4427 /* Pick right bitmask word from Bloom filter array */ 4428 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4429 obj->maskwords_bm_gnu]; 4430 4431 /* Calculate modulus word size of gnu hash and its derivative */ 4432 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4433 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4434 4435 /* Filter out the "definitely not in set" queries */ 4436 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4437 return (ESRCH); 4438 4439 /* Locate hash chain and corresponding value element*/ 4440 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4441 if (bucket == 0) 4442 return (ESRCH); 4443 hashval = &obj->chain_zero_gnu[bucket]; 4444 do { 4445 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4446 symnum = hashval - obj->chain_zero_gnu; 4447 if (matched_symbol(req, obj, &matchres, symnum)) { 4448 req->sym_out = matchres.sym_out; 4449 req->defobj_out = obj; 4450 return (0); 4451 } 4452 } 4453 } while ((*hashval++ & 1) == 0); 4454 if (matchres.vcount == 1) { 4455 req->sym_out = matchres.vsymp; 4456 req->defobj_out = obj; 4457 return (0); 4458 } 4459 return (ESRCH); 4460 } 4461 4462 static void 4463 trace_loaded_objects(Obj_Entry *obj) 4464 { 4465 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4466 int c; 4467 4468 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4469 main_local = ""; 4470 4471 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4472 fmt1 = "\t%o => %p (%x)\n"; 4473 4474 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4475 fmt2 = "\t%o (%x)\n"; 4476 4477 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4478 4479 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4480 Needed_Entry *needed; 4481 char *name, *path; 4482 bool is_lib; 4483 4484 if (obj->marker) 4485 continue; 4486 if (list_containers && obj->needed != NULL) 4487 rtld_printf("%s:\n", obj->path); 4488 for (needed = obj->needed; needed; needed = needed->next) { 4489 if (needed->obj != NULL) { 4490 if (needed->obj->traced && !list_containers) 4491 continue; 4492 needed->obj->traced = true; 4493 path = needed->obj->path; 4494 } else 4495 path = "not found"; 4496 4497 name = (char *)obj->strtab + needed->name; 4498 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4499 4500 fmt = is_lib ? fmt1 : fmt2; 4501 while ((c = *fmt++) != '\0') { 4502 switch (c) { 4503 default: 4504 rtld_putchar(c); 4505 continue; 4506 case '\\': 4507 switch (c = *fmt) { 4508 case '\0': 4509 continue; 4510 case 'n': 4511 rtld_putchar('\n'); 4512 break; 4513 case 't': 4514 rtld_putchar('\t'); 4515 break; 4516 } 4517 break; 4518 case '%': 4519 switch (c = *fmt) { 4520 case '\0': 4521 continue; 4522 case '%': 4523 default: 4524 rtld_putchar(c); 4525 break; 4526 case 'A': 4527 rtld_putstr(main_local); 4528 break; 4529 case 'a': 4530 rtld_putstr(obj_main->path); 4531 break; 4532 case 'o': 4533 rtld_putstr(name); 4534 break; 4535 #if 0 4536 case 'm': 4537 rtld_printf("%d", sodp->sod_major); 4538 break; 4539 case 'n': 4540 rtld_printf("%d", sodp->sod_minor); 4541 break; 4542 #endif 4543 case 'p': 4544 rtld_putstr(path); 4545 break; 4546 case 'x': 4547 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4548 0); 4549 break; 4550 } 4551 break; 4552 } 4553 ++fmt; 4554 } 4555 } 4556 } 4557 } 4558 4559 /* 4560 * Unload a dlopened object and its dependencies from memory and from 4561 * our data structures. It is assumed that the DAG rooted in the 4562 * object has already been unreferenced, and that the object has a 4563 * reference count of 0. 4564 */ 4565 static void 4566 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4567 { 4568 Obj_Entry marker, *obj, *next; 4569 4570 assert(root->refcount == 0); 4571 4572 /* 4573 * Pass over the DAG removing unreferenced objects from 4574 * appropriate lists. 4575 */ 4576 unlink_object(root); 4577 4578 /* Unmap all objects that are no longer referenced. */ 4579 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4580 next = TAILQ_NEXT(obj, next); 4581 if (obj->marker || obj->refcount != 0) 4582 continue; 4583 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4584 obj->mapsize, 0, obj->path); 4585 dbg("unloading \"%s\"", obj->path); 4586 /* 4587 * Unlink the object now to prevent new references from 4588 * being acquired while the bind lock is dropped in 4589 * recursive dlclose() invocations. 4590 */ 4591 TAILQ_REMOVE(&obj_list, obj, next); 4592 obj_count--; 4593 4594 if (obj->filtees_loaded) { 4595 if (next != NULL) { 4596 init_marker(&marker); 4597 TAILQ_INSERT_BEFORE(next, &marker, next); 4598 unload_filtees(obj, lockstate); 4599 next = TAILQ_NEXT(&marker, next); 4600 TAILQ_REMOVE(&obj_list, &marker, next); 4601 } else 4602 unload_filtees(obj, lockstate); 4603 } 4604 release_object(obj); 4605 } 4606 } 4607 4608 static void 4609 unlink_object(Obj_Entry *root) 4610 { 4611 Objlist_Entry *elm; 4612 4613 if (root->refcount == 0) { 4614 /* Remove the object from the RTLD_GLOBAL list. */ 4615 objlist_remove(&list_global, root); 4616 4617 /* Remove the object from all objects' DAG lists. */ 4618 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4619 objlist_remove(&elm->obj->dldags, root); 4620 if (elm->obj != root) 4621 unlink_object(elm->obj); 4622 } 4623 } 4624 } 4625 4626 static void 4627 ref_dag(Obj_Entry *root) 4628 { 4629 Objlist_Entry *elm; 4630 4631 assert(root->dag_inited); 4632 STAILQ_FOREACH(elm, &root->dagmembers, link) 4633 elm->obj->refcount++; 4634 } 4635 4636 static void 4637 unref_dag(Obj_Entry *root) 4638 { 4639 Objlist_Entry *elm; 4640 4641 assert(root->dag_inited); 4642 STAILQ_FOREACH(elm, &root->dagmembers, link) 4643 elm->obj->refcount--; 4644 } 4645 4646 /* 4647 * Common code for MD __tls_get_addr(). 4648 */ 4649 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4650 static void * 4651 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4652 { 4653 Elf_Addr *newdtv, *dtv; 4654 RtldLockState lockstate; 4655 int to_copy; 4656 4657 dtv = *dtvp; 4658 /* Check dtv generation in case new modules have arrived */ 4659 if (dtv[0] != tls_dtv_generation) { 4660 wlock_acquire(rtld_bind_lock, &lockstate); 4661 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4662 to_copy = dtv[1]; 4663 if (to_copy > tls_max_index) 4664 to_copy = tls_max_index; 4665 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4666 newdtv[0] = tls_dtv_generation; 4667 newdtv[1] = tls_max_index; 4668 free(dtv); 4669 lock_release(rtld_bind_lock, &lockstate); 4670 dtv = *dtvp = newdtv; 4671 } 4672 4673 /* Dynamically allocate module TLS if necessary */ 4674 if (dtv[index + 1] == 0) { 4675 /* Signal safe, wlock will block out signals. */ 4676 wlock_acquire(rtld_bind_lock, &lockstate); 4677 if (!dtv[index + 1]) 4678 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4679 lock_release(rtld_bind_lock, &lockstate); 4680 } 4681 return ((void *)(dtv[index + 1] + offset)); 4682 } 4683 4684 void * 4685 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4686 { 4687 Elf_Addr *dtv; 4688 4689 dtv = *dtvp; 4690 /* Check dtv generation in case new modules have arrived */ 4691 if (__predict_true(dtv[0] == tls_dtv_generation && 4692 dtv[index + 1] != 0)) 4693 return ((void *)(dtv[index + 1] + offset)); 4694 return (tls_get_addr_slow(dtvp, index, offset)); 4695 } 4696 4697 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4698 defined(__powerpc__) || defined(__riscv) 4699 4700 /* 4701 * Allocate Static TLS using the Variant I method. 4702 */ 4703 void * 4704 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4705 { 4706 Obj_Entry *obj; 4707 char *tcb; 4708 Elf_Addr **tls; 4709 Elf_Addr *dtv; 4710 Elf_Addr addr; 4711 int i; 4712 4713 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4714 return (oldtcb); 4715 4716 assert(tcbsize >= TLS_TCB_SIZE); 4717 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4718 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4719 4720 if (oldtcb != NULL) { 4721 memcpy(tls, oldtcb, tls_static_space); 4722 free(oldtcb); 4723 4724 /* Adjust the DTV. */ 4725 dtv = tls[0]; 4726 for (i = 0; i < dtv[1]; i++) { 4727 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4728 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4729 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4730 } 4731 } 4732 } else { 4733 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4734 tls[0] = dtv; 4735 dtv[0] = tls_dtv_generation; 4736 dtv[1] = tls_max_index; 4737 4738 for (obj = globallist_curr(objs); obj != NULL; 4739 obj = globallist_next(obj)) { 4740 if (obj->tlsoffset > 0) { 4741 addr = (Elf_Addr)tls + obj->tlsoffset; 4742 if (obj->tlsinitsize > 0) 4743 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4744 if (obj->tlssize > obj->tlsinitsize) 4745 memset((void*) (addr + obj->tlsinitsize), 0, 4746 obj->tlssize - obj->tlsinitsize); 4747 dtv[obj->tlsindex + 1] = addr; 4748 } 4749 } 4750 } 4751 4752 return (tcb); 4753 } 4754 4755 void 4756 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4757 { 4758 Elf_Addr *dtv; 4759 Elf_Addr tlsstart, tlsend; 4760 int dtvsize, i; 4761 4762 assert(tcbsize >= TLS_TCB_SIZE); 4763 4764 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4765 tlsend = tlsstart + tls_static_space; 4766 4767 dtv = *(Elf_Addr **)tlsstart; 4768 dtvsize = dtv[1]; 4769 for (i = 0; i < dtvsize; i++) { 4770 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4771 free((void*)dtv[i+2]); 4772 } 4773 } 4774 free(dtv); 4775 free(tcb); 4776 } 4777 4778 #endif 4779 4780 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4781 4782 /* 4783 * Allocate Static TLS using the Variant II method. 4784 */ 4785 void * 4786 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4787 { 4788 Obj_Entry *obj; 4789 size_t size, ralign; 4790 char *tls; 4791 Elf_Addr *dtv, *olddtv; 4792 Elf_Addr segbase, oldsegbase, addr; 4793 int i; 4794 4795 ralign = tcbalign; 4796 if (tls_static_max_align > ralign) 4797 ralign = tls_static_max_align; 4798 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4799 4800 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4801 tls = malloc_aligned(size, ralign); 4802 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4803 4804 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4805 ((Elf_Addr*)segbase)[0] = segbase; 4806 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4807 4808 dtv[0] = tls_dtv_generation; 4809 dtv[1] = tls_max_index; 4810 4811 if (oldtls) { 4812 /* 4813 * Copy the static TLS block over whole. 4814 */ 4815 oldsegbase = (Elf_Addr) oldtls; 4816 memcpy((void *)(segbase - tls_static_space), 4817 (const void *)(oldsegbase - tls_static_space), 4818 tls_static_space); 4819 4820 /* 4821 * If any dynamic TLS blocks have been created tls_get_addr(), 4822 * move them over. 4823 */ 4824 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4825 for (i = 0; i < olddtv[1]; i++) { 4826 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4827 dtv[i+2] = olddtv[i+2]; 4828 olddtv[i+2] = 0; 4829 } 4830 } 4831 4832 /* 4833 * We assume that this block was the one we created with 4834 * allocate_initial_tls(). 4835 */ 4836 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4837 } else { 4838 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4839 if (obj->marker || obj->tlsoffset == 0) 4840 continue; 4841 addr = segbase - obj->tlsoffset; 4842 memset((void*) (addr + obj->tlsinitsize), 4843 0, obj->tlssize - obj->tlsinitsize); 4844 if (obj->tlsinit) 4845 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4846 dtv[obj->tlsindex + 1] = addr; 4847 } 4848 } 4849 4850 return (void*) segbase; 4851 } 4852 4853 void 4854 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4855 { 4856 Elf_Addr* dtv; 4857 size_t size, ralign; 4858 int dtvsize, i; 4859 Elf_Addr tlsstart, tlsend; 4860 4861 /* 4862 * Figure out the size of the initial TLS block so that we can 4863 * find stuff which ___tls_get_addr() allocated dynamically. 4864 */ 4865 ralign = tcbalign; 4866 if (tls_static_max_align > ralign) 4867 ralign = tls_static_max_align; 4868 size = round(tls_static_space, ralign); 4869 4870 dtv = ((Elf_Addr**)tls)[1]; 4871 dtvsize = dtv[1]; 4872 tlsend = (Elf_Addr) tls; 4873 tlsstart = tlsend - size; 4874 for (i = 0; i < dtvsize; i++) { 4875 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4876 free_aligned((void *)dtv[i + 2]); 4877 } 4878 } 4879 4880 free_aligned((void *)tlsstart); 4881 free((void*) dtv); 4882 } 4883 4884 #endif 4885 4886 /* 4887 * Allocate TLS block for module with given index. 4888 */ 4889 void * 4890 allocate_module_tls(int index) 4891 { 4892 Obj_Entry* obj; 4893 char* p; 4894 4895 TAILQ_FOREACH(obj, &obj_list, next) { 4896 if (obj->marker) 4897 continue; 4898 if (obj->tlsindex == index) 4899 break; 4900 } 4901 if (!obj) { 4902 _rtld_error("Can't find module with TLS index %d", index); 4903 rtld_die(); 4904 } 4905 4906 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4907 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4908 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4909 4910 return p; 4911 } 4912 4913 bool 4914 allocate_tls_offset(Obj_Entry *obj) 4915 { 4916 size_t off; 4917 4918 if (obj->tls_done) 4919 return true; 4920 4921 if (obj->tlssize == 0) { 4922 obj->tls_done = true; 4923 return true; 4924 } 4925 4926 if (tls_last_offset == 0) 4927 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4928 else 4929 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4930 obj->tlssize, obj->tlsalign); 4931 4932 /* 4933 * If we have already fixed the size of the static TLS block, we 4934 * must stay within that size. When allocating the static TLS, we 4935 * leave a small amount of space spare to be used for dynamically 4936 * loading modules which use static TLS. 4937 */ 4938 if (tls_static_space != 0) { 4939 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4940 return false; 4941 } else if (obj->tlsalign > tls_static_max_align) { 4942 tls_static_max_align = obj->tlsalign; 4943 } 4944 4945 tls_last_offset = obj->tlsoffset = off; 4946 tls_last_size = obj->tlssize; 4947 obj->tls_done = true; 4948 4949 return true; 4950 } 4951 4952 void 4953 free_tls_offset(Obj_Entry *obj) 4954 { 4955 4956 /* 4957 * If we were the last thing to allocate out of the static TLS 4958 * block, we give our space back to the 'allocator'. This is a 4959 * simplistic workaround to allow libGL.so.1 to be loaded and 4960 * unloaded multiple times. 4961 */ 4962 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4963 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4964 tls_last_offset -= obj->tlssize; 4965 tls_last_size = 0; 4966 } 4967 } 4968 4969 void * 4970 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4971 { 4972 void *ret; 4973 RtldLockState lockstate; 4974 4975 wlock_acquire(rtld_bind_lock, &lockstate); 4976 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4977 tcbsize, tcbalign); 4978 lock_release(rtld_bind_lock, &lockstate); 4979 return (ret); 4980 } 4981 4982 void 4983 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4984 { 4985 RtldLockState lockstate; 4986 4987 wlock_acquire(rtld_bind_lock, &lockstate); 4988 free_tls(tcb, tcbsize, tcbalign); 4989 lock_release(rtld_bind_lock, &lockstate); 4990 } 4991 4992 static void 4993 object_add_name(Obj_Entry *obj, const char *name) 4994 { 4995 Name_Entry *entry; 4996 size_t len; 4997 4998 len = strlen(name); 4999 entry = malloc(sizeof(Name_Entry) + len); 5000 5001 if (entry != NULL) { 5002 strcpy(entry->name, name); 5003 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5004 } 5005 } 5006 5007 static int 5008 object_match_name(const Obj_Entry *obj, const char *name) 5009 { 5010 Name_Entry *entry; 5011 5012 STAILQ_FOREACH(entry, &obj->names, link) { 5013 if (strcmp(name, entry->name) == 0) 5014 return (1); 5015 } 5016 return (0); 5017 } 5018 5019 static Obj_Entry * 5020 locate_dependency(const Obj_Entry *obj, const char *name) 5021 { 5022 const Objlist_Entry *entry; 5023 const Needed_Entry *needed; 5024 5025 STAILQ_FOREACH(entry, &list_main, link) { 5026 if (object_match_name(entry->obj, name)) 5027 return entry->obj; 5028 } 5029 5030 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5031 if (strcmp(obj->strtab + needed->name, name) == 0 || 5032 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5033 /* 5034 * If there is DT_NEEDED for the name we are looking for, 5035 * we are all set. Note that object might not be found if 5036 * dependency was not loaded yet, so the function can 5037 * return NULL here. This is expected and handled 5038 * properly by the caller. 5039 */ 5040 return (needed->obj); 5041 } 5042 } 5043 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5044 obj->path, name); 5045 rtld_die(); 5046 } 5047 5048 static int 5049 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5050 const Elf_Vernaux *vna) 5051 { 5052 const Elf_Verdef *vd; 5053 const char *vername; 5054 5055 vername = refobj->strtab + vna->vna_name; 5056 vd = depobj->verdef; 5057 if (vd == NULL) { 5058 _rtld_error("%s: version %s required by %s not defined", 5059 depobj->path, vername, refobj->path); 5060 return (-1); 5061 } 5062 for (;;) { 5063 if (vd->vd_version != VER_DEF_CURRENT) { 5064 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5065 depobj->path, vd->vd_version); 5066 return (-1); 5067 } 5068 if (vna->vna_hash == vd->vd_hash) { 5069 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5070 ((char *)vd + vd->vd_aux); 5071 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5072 return (0); 5073 } 5074 if (vd->vd_next == 0) 5075 break; 5076 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5077 } 5078 if (vna->vna_flags & VER_FLG_WEAK) 5079 return (0); 5080 _rtld_error("%s: version %s required by %s not found", 5081 depobj->path, vername, refobj->path); 5082 return (-1); 5083 } 5084 5085 static int 5086 rtld_verify_object_versions(Obj_Entry *obj) 5087 { 5088 const Elf_Verneed *vn; 5089 const Elf_Verdef *vd; 5090 const Elf_Verdaux *vda; 5091 const Elf_Vernaux *vna; 5092 const Obj_Entry *depobj; 5093 int maxvernum, vernum; 5094 5095 if (obj->ver_checked) 5096 return (0); 5097 obj->ver_checked = true; 5098 5099 maxvernum = 0; 5100 /* 5101 * Walk over defined and required version records and figure out 5102 * max index used by any of them. Do very basic sanity checking 5103 * while there. 5104 */ 5105 vn = obj->verneed; 5106 while (vn != NULL) { 5107 if (vn->vn_version != VER_NEED_CURRENT) { 5108 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5109 obj->path, vn->vn_version); 5110 return (-1); 5111 } 5112 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5113 for (;;) { 5114 vernum = VER_NEED_IDX(vna->vna_other); 5115 if (vernum > maxvernum) 5116 maxvernum = vernum; 5117 if (vna->vna_next == 0) 5118 break; 5119 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5120 } 5121 if (vn->vn_next == 0) 5122 break; 5123 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5124 } 5125 5126 vd = obj->verdef; 5127 while (vd != NULL) { 5128 if (vd->vd_version != VER_DEF_CURRENT) { 5129 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5130 obj->path, vd->vd_version); 5131 return (-1); 5132 } 5133 vernum = VER_DEF_IDX(vd->vd_ndx); 5134 if (vernum > maxvernum) 5135 maxvernum = vernum; 5136 if (vd->vd_next == 0) 5137 break; 5138 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5139 } 5140 5141 if (maxvernum == 0) 5142 return (0); 5143 5144 /* 5145 * Store version information in array indexable by version index. 5146 * Verify that object version requirements are satisfied along the 5147 * way. 5148 */ 5149 obj->vernum = maxvernum + 1; 5150 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5151 5152 vd = obj->verdef; 5153 while (vd != NULL) { 5154 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5155 vernum = VER_DEF_IDX(vd->vd_ndx); 5156 assert(vernum <= maxvernum); 5157 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5158 obj->vertab[vernum].hash = vd->vd_hash; 5159 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5160 obj->vertab[vernum].file = NULL; 5161 obj->vertab[vernum].flags = 0; 5162 } 5163 if (vd->vd_next == 0) 5164 break; 5165 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5166 } 5167 5168 vn = obj->verneed; 5169 while (vn != NULL) { 5170 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5171 if (depobj == NULL) 5172 return (-1); 5173 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5174 for (;;) { 5175 if (check_object_provided_version(obj, depobj, vna)) 5176 return (-1); 5177 vernum = VER_NEED_IDX(vna->vna_other); 5178 assert(vernum <= maxvernum); 5179 obj->vertab[vernum].hash = vna->vna_hash; 5180 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5181 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5182 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5183 VER_INFO_HIDDEN : 0; 5184 if (vna->vna_next == 0) 5185 break; 5186 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5187 } 5188 if (vn->vn_next == 0) 5189 break; 5190 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5191 } 5192 return 0; 5193 } 5194 5195 static int 5196 rtld_verify_versions(const Objlist *objlist) 5197 { 5198 Objlist_Entry *entry; 5199 int rc; 5200 5201 rc = 0; 5202 STAILQ_FOREACH(entry, objlist, link) { 5203 /* 5204 * Skip dummy objects or objects that have their version requirements 5205 * already checked. 5206 */ 5207 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5208 continue; 5209 if (rtld_verify_object_versions(entry->obj) == -1) { 5210 rc = -1; 5211 if (ld_tracing == NULL) 5212 break; 5213 } 5214 } 5215 if (rc == 0 || ld_tracing != NULL) 5216 rc = rtld_verify_object_versions(&obj_rtld); 5217 return rc; 5218 } 5219 5220 const Ver_Entry * 5221 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5222 { 5223 Elf_Versym vernum; 5224 5225 if (obj->vertab) { 5226 vernum = VER_NDX(obj->versyms[symnum]); 5227 if (vernum >= obj->vernum) { 5228 _rtld_error("%s: symbol %s has wrong verneed value %d", 5229 obj->path, obj->strtab + symnum, vernum); 5230 } else if (obj->vertab[vernum].hash != 0) { 5231 return &obj->vertab[vernum]; 5232 } 5233 } 5234 return NULL; 5235 } 5236 5237 int 5238 _rtld_get_stack_prot(void) 5239 { 5240 5241 return (stack_prot); 5242 } 5243 5244 int 5245 _rtld_is_dlopened(void *arg) 5246 { 5247 Obj_Entry *obj; 5248 RtldLockState lockstate; 5249 int res; 5250 5251 rlock_acquire(rtld_bind_lock, &lockstate); 5252 obj = dlcheck(arg); 5253 if (obj == NULL) 5254 obj = obj_from_addr(arg); 5255 if (obj == NULL) { 5256 _rtld_error("No shared object contains address"); 5257 lock_release(rtld_bind_lock, &lockstate); 5258 return (-1); 5259 } 5260 res = obj->dlopened ? 1 : 0; 5261 lock_release(rtld_bind_lock, &lockstate); 5262 return (res); 5263 } 5264 5265 int 5266 obj_enforce_relro(Obj_Entry *obj) 5267 { 5268 5269 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5270 PROT_READ) == -1) { 5271 _rtld_error("%s: Cannot enforce relro protection: %s", 5272 obj->path, rtld_strerror(errno)); 5273 return (-1); 5274 } 5275 return (0); 5276 } 5277 5278 static void 5279 map_stacks_exec(RtldLockState *lockstate) 5280 { 5281 void (*thr_map_stacks_exec)(void); 5282 5283 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5284 return; 5285 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5286 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5287 if (thr_map_stacks_exec != NULL) { 5288 stack_prot |= PROT_EXEC; 5289 thr_map_stacks_exec(); 5290 } 5291 } 5292 5293 void 5294 symlook_init(SymLook *dst, const char *name) 5295 { 5296 5297 bzero(dst, sizeof(*dst)); 5298 dst->name = name; 5299 dst->hash = elf_hash(name); 5300 dst->hash_gnu = gnu_hash(name); 5301 } 5302 5303 static void 5304 symlook_init_from_req(SymLook *dst, const SymLook *src) 5305 { 5306 5307 dst->name = src->name; 5308 dst->hash = src->hash; 5309 dst->hash_gnu = src->hash_gnu; 5310 dst->ventry = src->ventry; 5311 dst->flags = src->flags; 5312 dst->defobj_out = NULL; 5313 dst->sym_out = NULL; 5314 dst->lockstate = src->lockstate; 5315 } 5316 5317 static int 5318 open_binary_fd(const char *argv0, bool search_in_path) 5319 { 5320 char *pathenv, *pe, binpath[PATH_MAX]; 5321 int fd; 5322 5323 if (search_in_path && strchr(argv0, '/') == NULL) { 5324 pathenv = getenv("PATH"); 5325 if (pathenv == NULL) { 5326 rtld_printf("-p and no PATH environment variable\n"); 5327 rtld_die(); 5328 } 5329 pathenv = strdup(pathenv); 5330 if (pathenv == NULL) { 5331 rtld_printf("Cannot allocate memory\n"); 5332 rtld_die(); 5333 } 5334 fd = -1; 5335 errno = ENOENT; 5336 while ((pe = strsep(&pathenv, ":")) != NULL) { 5337 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5338 sizeof(binpath)) 5339 continue; 5340 if (binpath[0] != '\0' && 5341 strlcat(binpath, "/", sizeof(binpath)) >= 5342 sizeof(binpath)) 5343 continue; 5344 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5345 sizeof(binpath)) 5346 continue; 5347 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5348 if (fd != -1 || errno != ENOENT) 5349 break; 5350 } 5351 free(pathenv); 5352 } else { 5353 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5354 } 5355 5356 if (fd == -1) { 5357 rtld_printf("Opening %s: %s\n", argv0, 5358 rtld_strerror(errno)); 5359 rtld_die(); 5360 } 5361 return (fd); 5362 } 5363 5364 /* 5365 * Parse a set of command-line arguments. 5366 */ 5367 static int 5368 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5369 { 5370 const char *arg; 5371 int fd, i, j, arglen; 5372 char opt; 5373 5374 dbg("Parsing command-line arguments"); 5375 *use_pathp = false; 5376 *fdp = -1; 5377 5378 for (i = 1; i < argc; i++ ) { 5379 arg = argv[i]; 5380 dbg("argv[%d]: '%s'", i, arg); 5381 5382 /* 5383 * rtld arguments end with an explicit "--" or with the first 5384 * non-prefixed argument. 5385 */ 5386 if (strcmp(arg, "--") == 0) { 5387 i++; 5388 break; 5389 } 5390 if (arg[0] != '-') 5391 break; 5392 5393 /* 5394 * All other arguments are single-character options that can 5395 * be combined, so we need to search through `arg` for them. 5396 */ 5397 arglen = strlen(arg); 5398 for (j = 1; j < arglen; j++) { 5399 opt = arg[j]; 5400 if (opt == 'h') { 5401 print_usage(argv[0]); 5402 rtld_die(); 5403 } else if (opt == 'f') { 5404 /* 5405 * -f XX can be used to specify a descriptor for the 5406 * binary named at the command line (i.e., the later 5407 * argument will specify the process name but the 5408 * descriptor is what will actually be executed) 5409 */ 5410 if (j != arglen - 1) { 5411 /* -f must be the last option in, e.g., -abcf */ 5412 _rtld_error("invalid options: %s", arg); 5413 rtld_die(); 5414 } 5415 i++; 5416 fd = parse_integer(argv[i]); 5417 if (fd == -1) { 5418 _rtld_error("invalid file descriptor: '%s'", 5419 argv[i]); 5420 rtld_die(); 5421 } 5422 *fdp = fd; 5423 break; 5424 } else if (opt == 'p') { 5425 *use_pathp = true; 5426 } else { 5427 rtld_printf("invalid argument: '%s'\n", arg); 5428 print_usage(argv[0]); 5429 rtld_die(); 5430 } 5431 } 5432 } 5433 5434 return (i); 5435 } 5436 5437 /* 5438 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5439 */ 5440 static int 5441 parse_integer(const char *str) 5442 { 5443 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5444 const char *orig; 5445 int n; 5446 char c; 5447 5448 orig = str; 5449 n = 0; 5450 for (c = *str; c != '\0'; c = *++str) { 5451 if (c < '0' || c > '9') 5452 return (-1); 5453 5454 n *= RADIX; 5455 n += c - '0'; 5456 } 5457 5458 /* Make sure we actually parsed something. */ 5459 if (str == orig) 5460 return (-1); 5461 return (n); 5462 } 5463 5464 static void 5465 print_usage(const char *argv0) 5466 { 5467 5468 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5469 "\n" 5470 "Options:\n" 5471 " -h Display this help message\n" 5472 " -p Search in PATH for named binary\n" 5473 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5474 " -- End of RTLD options\n" 5475 " <binary> Name of process to execute\n" 5476 " <args> Arguments to the executed process\n", argv0); 5477 } 5478 5479 /* 5480 * Overrides for libc_pic-provided functions. 5481 */ 5482 5483 int 5484 __getosreldate(void) 5485 { 5486 size_t len; 5487 int oid[2]; 5488 int error, osrel; 5489 5490 if (osreldate != 0) 5491 return (osreldate); 5492 5493 oid[0] = CTL_KERN; 5494 oid[1] = KERN_OSRELDATE; 5495 osrel = 0; 5496 len = sizeof(osrel); 5497 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5498 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5499 osreldate = osrel; 5500 return (osreldate); 5501 } 5502 5503 void 5504 exit(int status) 5505 { 5506 5507 _exit(status); 5508 } 5509 5510 void (*__cleanup)(void); 5511 int __isthreaded = 0; 5512 int _thread_autoinit_dummy_decl = 1; 5513 5514 /* 5515 * No unresolved symbols for rtld. 5516 */ 5517 void 5518 __pthread_cxa_finalize(struct dl_phdr_info *a) 5519 { 5520 } 5521 5522 void 5523 __stack_chk_fail(void) 5524 { 5525 5526 _rtld_error("stack overflow detected; terminated"); 5527 rtld_die(); 5528 } 5529 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5530 5531 void 5532 __chk_fail(void) 5533 { 5534 5535 _rtld_error("buffer overflow detected; terminated"); 5536 rtld_die(); 5537 } 5538 5539 const char * 5540 rtld_strerror(int errnum) 5541 { 5542 5543 if (errnum < 0 || errnum >= sys_nerr) 5544 return ("Unknown error"); 5545 return (sys_errlist[errnum]); 5546 } 5547