1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 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 <jdp@polstra.com>. 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 for shared object \"%s\"", 1607 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 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1624 (refobj != NULL && 1625 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1626 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1627 (pathname = search_library_path(name, gethints(false))) != NULL || 1628 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1629 return (pathname); 1630 } else { 1631 nodeflib = objgiven ? refobj->z_nodeflib : false; 1632 if ((objgiven && 1633 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1634 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1635 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1636 (pathname = search_library_path(name, ld_library_path)) != NULL || 1637 (objgiven && 1638 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1639 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1640 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1641 (objgiven && !nodeflib && 1642 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1643 return (pathname); 1644 } 1645 1646 if (objgiven && refobj->path != NULL) { 1647 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1648 name, basename(refobj->path)); 1649 } else { 1650 _rtld_error("Shared object \"%s\" not found", name); 1651 } 1652 return NULL; 1653 } 1654 1655 /* 1656 * Given a symbol number in a referencing object, find the corresponding 1657 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1658 * no definition was found. Returns a pointer to the Obj_Entry of the 1659 * defining object via the reference parameter DEFOBJ_OUT. 1660 */ 1661 const Elf_Sym * 1662 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1663 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1664 RtldLockState *lockstate) 1665 { 1666 const Elf_Sym *ref; 1667 const Elf_Sym *def; 1668 const Obj_Entry *defobj; 1669 const Ver_Entry *ve; 1670 SymLook req; 1671 const char *name; 1672 int res; 1673 1674 /* 1675 * If we have already found this symbol, get the information from 1676 * the cache. 1677 */ 1678 if (symnum >= refobj->dynsymcount) 1679 return NULL; /* Bad object */ 1680 if (cache != NULL && cache[symnum].sym != NULL) { 1681 *defobj_out = cache[symnum].obj; 1682 return cache[symnum].sym; 1683 } 1684 1685 ref = refobj->symtab + symnum; 1686 name = refobj->strtab + ref->st_name; 1687 def = NULL; 1688 defobj = NULL; 1689 ve = NULL; 1690 1691 /* 1692 * We don't have to do a full scale lookup if the symbol is local. 1693 * We know it will bind to the instance in this load module; to 1694 * which we already have a pointer (ie ref). By not doing a lookup, 1695 * we not only improve performance, but it also avoids unresolvable 1696 * symbols when local symbols are not in the hash table. This has 1697 * been seen with the ia64 toolchain. 1698 */ 1699 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1700 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1701 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1702 symnum); 1703 } 1704 symlook_init(&req, name); 1705 req.flags = flags; 1706 ve = req.ventry = fetch_ventry(refobj, symnum); 1707 req.lockstate = lockstate; 1708 res = symlook_default(&req, refobj); 1709 if (res == 0) { 1710 def = req.sym_out; 1711 defobj = req.defobj_out; 1712 } 1713 } else { 1714 def = ref; 1715 defobj = refobj; 1716 } 1717 1718 /* 1719 * If we found no definition and the reference is weak, treat the 1720 * symbol as having the value zero. 1721 */ 1722 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1723 def = &sym_zero; 1724 defobj = obj_main; 1725 } 1726 1727 if (def != NULL) { 1728 *defobj_out = defobj; 1729 /* Record the information in the cache to avoid subsequent lookups. */ 1730 if (cache != NULL) { 1731 cache[symnum].sym = def; 1732 cache[symnum].obj = defobj; 1733 } 1734 } else { 1735 if (refobj != &obj_rtld) 1736 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1737 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1738 } 1739 return def; 1740 } 1741 1742 /* 1743 * Return the search path from the ldconfig hints file, reading it if 1744 * necessary. If nostdlib is true, then the default search paths are 1745 * not added to result. 1746 * 1747 * Returns NULL if there are problems with the hints file, 1748 * or if the search path there is empty. 1749 */ 1750 static const char * 1751 gethints(bool nostdlib) 1752 { 1753 static char *hints, *filtered_path; 1754 static struct elfhints_hdr hdr; 1755 struct fill_search_info_args sargs, hargs; 1756 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1757 struct dl_serpath *SLPpath, *hintpath; 1758 char *p; 1759 struct stat hint_stat; 1760 unsigned int SLPndx, hintndx, fndx, fcount; 1761 int fd; 1762 size_t flen; 1763 uint32_t dl; 1764 bool skip; 1765 1766 /* First call, read the hints file */ 1767 if (hints == NULL) { 1768 /* Keep from trying again in case the hints file is bad. */ 1769 hints = ""; 1770 1771 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1772 return (NULL); 1773 1774 /* 1775 * Check of hdr.dirlistlen value against type limit 1776 * intends to pacify static analyzers. Further 1777 * paranoia leads to checks that dirlist is fully 1778 * contained in the file range. 1779 */ 1780 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1781 hdr.magic != ELFHINTS_MAGIC || 1782 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1783 fstat(fd, &hint_stat) == -1) { 1784 cleanup1: 1785 close(fd); 1786 hdr.dirlistlen = 0; 1787 return (NULL); 1788 } 1789 dl = hdr.strtab; 1790 if (dl + hdr.dirlist < dl) 1791 goto cleanup1; 1792 dl += hdr.dirlist; 1793 if (dl + hdr.dirlistlen < dl) 1794 goto cleanup1; 1795 dl += hdr.dirlistlen; 1796 if (dl > hint_stat.st_size) 1797 goto cleanup1; 1798 p = xmalloc(hdr.dirlistlen + 1); 1799 1800 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1801 read(fd, p, hdr.dirlistlen + 1) != 1802 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1803 free(p); 1804 goto cleanup1; 1805 } 1806 hints = p; 1807 close(fd); 1808 } 1809 1810 /* 1811 * If caller agreed to receive list which includes the default 1812 * paths, we are done. Otherwise, if we still did not 1813 * calculated filtered result, do it now. 1814 */ 1815 if (!nostdlib) 1816 return (hints[0] != '\0' ? hints : NULL); 1817 if (filtered_path != NULL) 1818 goto filt_ret; 1819 1820 /* 1821 * Obtain the list of all configured search paths, and the 1822 * list of the default paths. 1823 * 1824 * First estimate the size of the results. 1825 */ 1826 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1827 smeta.dls_cnt = 0; 1828 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1829 hmeta.dls_cnt = 0; 1830 1831 sargs.request = RTLD_DI_SERINFOSIZE; 1832 sargs.serinfo = &smeta; 1833 hargs.request = RTLD_DI_SERINFOSIZE; 1834 hargs.serinfo = &hmeta; 1835 1836 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1837 path_enumerate(hints, fill_search_info, &hargs); 1838 1839 SLPinfo = xmalloc(smeta.dls_size); 1840 hintinfo = xmalloc(hmeta.dls_size); 1841 1842 /* 1843 * Next fetch both sets of paths. 1844 */ 1845 sargs.request = RTLD_DI_SERINFO; 1846 sargs.serinfo = SLPinfo; 1847 sargs.serpath = &SLPinfo->dls_serpath[0]; 1848 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1849 1850 hargs.request = RTLD_DI_SERINFO; 1851 hargs.serinfo = hintinfo; 1852 hargs.serpath = &hintinfo->dls_serpath[0]; 1853 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1854 1855 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1856 path_enumerate(hints, fill_search_info, &hargs); 1857 1858 /* 1859 * Now calculate the difference between two sets, by excluding 1860 * standard paths from the full set. 1861 */ 1862 fndx = 0; 1863 fcount = 0; 1864 filtered_path = xmalloc(hdr.dirlistlen + 1); 1865 hintpath = &hintinfo->dls_serpath[0]; 1866 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1867 skip = false; 1868 SLPpath = &SLPinfo->dls_serpath[0]; 1869 /* 1870 * Check each standard path against current. 1871 */ 1872 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1873 /* matched, skip the path */ 1874 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1875 skip = true; 1876 break; 1877 } 1878 } 1879 if (skip) 1880 continue; 1881 /* 1882 * Not matched against any standard path, add the path 1883 * to result. Separate consequtive paths with ':'. 1884 */ 1885 if (fcount > 0) { 1886 filtered_path[fndx] = ':'; 1887 fndx++; 1888 } 1889 fcount++; 1890 flen = strlen(hintpath->dls_name); 1891 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1892 fndx += flen; 1893 } 1894 filtered_path[fndx] = '\0'; 1895 1896 free(SLPinfo); 1897 free(hintinfo); 1898 1899 filt_ret: 1900 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1901 } 1902 1903 static void 1904 init_dag(Obj_Entry *root) 1905 { 1906 const Needed_Entry *needed; 1907 const Objlist_Entry *elm; 1908 DoneList donelist; 1909 1910 if (root->dag_inited) 1911 return; 1912 donelist_init(&donelist); 1913 1914 /* Root object belongs to own DAG. */ 1915 objlist_push_tail(&root->dldags, root); 1916 objlist_push_tail(&root->dagmembers, root); 1917 donelist_check(&donelist, root); 1918 1919 /* 1920 * Add dependencies of root object to DAG in breadth order 1921 * by exploiting the fact that each new object get added 1922 * to the tail of the dagmembers list. 1923 */ 1924 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1925 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1926 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1927 continue; 1928 objlist_push_tail(&needed->obj->dldags, root); 1929 objlist_push_tail(&root->dagmembers, needed->obj); 1930 } 1931 } 1932 root->dag_inited = true; 1933 } 1934 1935 static void 1936 init_marker(Obj_Entry *marker) 1937 { 1938 1939 bzero(marker, sizeof(*marker)); 1940 marker->marker = true; 1941 } 1942 1943 Obj_Entry * 1944 globallist_curr(const Obj_Entry *obj) 1945 { 1946 1947 for (;;) { 1948 if (obj == NULL) 1949 return (NULL); 1950 if (!obj->marker) 1951 return (__DECONST(Obj_Entry *, obj)); 1952 obj = TAILQ_PREV(obj, obj_entry_q, next); 1953 } 1954 } 1955 1956 Obj_Entry * 1957 globallist_next(const Obj_Entry *obj) 1958 { 1959 1960 for (;;) { 1961 obj = TAILQ_NEXT(obj, next); 1962 if (obj == NULL) 1963 return (NULL); 1964 if (!obj->marker) 1965 return (__DECONST(Obj_Entry *, obj)); 1966 } 1967 } 1968 1969 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1970 static void 1971 hold_object(Obj_Entry *obj) 1972 { 1973 1974 obj->holdcount++; 1975 } 1976 1977 static void 1978 unhold_object(Obj_Entry *obj) 1979 { 1980 1981 assert(obj->holdcount > 0); 1982 if (--obj->holdcount == 0 && obj->unholdfree) 1983 release_object(obj); 1984 } 1985 1986 static void 1987 process_z(Obj_Entry *root) 1988 { 1989 const Objlist_Entry *elm; 1990 Obj_Entry *obj; 1991 1992 /* 1993 * Walk over object DAG and process every dependent object 1994 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1995 * to grow their own DAG. 1996 * 1997 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1998 * symlook_global() to work. 1999 * 2000 * For DF_1_NODELETE, the DAG should have its reference upped. 2001 */ 2002 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2003 obj = elm->obj; 2004 if (obj == NULL) 2005 continue; 2006 if (obj->z_nodelete && !obj->ref_nodel) { 2007 dbg("obj %s -z nodelete", obj->path); 2008 init_dag(obj); 2009 ref_dag(obj); 2010 obj->ref_nodel = true; 2011 } 2012 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2013 dbg("obj %s -z global", obj->path); 2014 objlist_push_tail(&list_global, obj); 2015 init_dag(obj); 2016 } 2017 } 2018 } 2019 /* 2020 * Initialize the dynamic linker. The argument is the address at which 2021 * the dynamic linker has been mapped into memory. The primary task of 2022 * this function is to relocate the dynamic linker. 2023 */ 2024 static void 2025 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2026 { 2027 Obj_Entry objtmp; /* Temporary rtld object */ 2028 const Elf_Ehdr *ehdr; 2029 const Elf_Dyn *dyn_rpath; 2030 const Elf_Dyn *dyn_soname; 2031 const Elf_Dyn *dyn_runpath; 2032 2033 #ifdef RTLD_INIT_PAGESIZES_EARLY 2034 /* The page size is required by the dynamic memory allocator. */ 2035 init_pagesizes(aux_info); 2036 #endif 2037 2038 /* 2039 * Conjure up an Obj_Entry structure for the dynamic linker. 2040 * 2041 * The "path" member can't be initialized yet because string constants 2042 * cannot yet be accessed. Below we will set it correctly. 2043 */ 2044 memset(&objtmp, 0, sizeof(objtmp)); 2045 objtmp.path = NULL; 2046 objtmp.rtld = true; 2047 objtmp.mapbase = mapbase; 2048 #ifdef PIC 2049 objtmp.relocbase = mapbase; 2050 #endif 2051 2052 objtmp.dynamic = rtld_dynamic(&objtmp); 2053 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2054 assert(objtmp.needed == NULL); 2055 #if !defined(__mips__) 2056 /* MIPS has a bogus DT_TEXTREL. */ 2057 assert(!objtmp.textrel); 2058 #endif 2059 /* 2060 * Temporarily put the dynamic linker entry into the object list, so 2061 * that symbols can be found. 2062 */ 2063 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2064 2065 ehdr = (Elf_Ehdr *)mapbase; 2066 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2067 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2068 2069 /* Initialize the object list. */ 2070 TAILQ_INIT(&obj_list); 2071 2072 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2073 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2074 2075 #ifndef RTLD_INIT_PAGESIZES_EARLY 2076 /* The page size is required by the dynamic memory allocator. */ 2077 init_pagesizes(aux_info); 2078 #endif 2079 2080 if (aux_info[AT_OSRELDATE] != NULL) 2081 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2082 2083 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2084 2085 /* Replace the path with a dynamically allocated copy. */ 2086 obj_rtld.path = xstrdup(ld_path_rtld); 2087 2088 r_debug.r_brk = r_debug_state; 2089 r_debug.r_state = RT_CONSISTENT; 2090 } 2091 2092 /* 2093 * Retrieve the array of supported page sizes. The kernel provides the page 2094 * sizes in increasing order. 2095 */ 2096 static void 2097 init_pagesizes(Elf_Auxinfo **aux_info) 2098 { 2099 static size_t psa[MAXPAGESIZES]; 2100 int mib[2]; 2101 size_t len, size; 2102 2103 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2104 NULL) { 2105 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2106 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2107 } else { 2108 len = 2; 2109 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2110 size = sizeof(psa); 2111 else { 2112 /* As a fallback, retrieve the base page size. */ 2113 size = sizeof(psa[0]); 2114 if (aux_info[AT_PAGESZ] != NULL) { 2115 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2116 goto psa_filled; 2117 } else { 2118 mib[0] = CTL_HW; 2119 mib[1] = HW_PAGESIZE; 2120 len = 2; 2121 } 2122 } 2123 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2124 _rtld_error("sysctl for hw.pagesize(s) failed"); 2125 rtld_die(); 2126 } 2127 psa_filled: 2128 pagesizes = psa; 2129 } 2130 npagesizes = size / sizeof(pagesizes[0]); 2131 /* Discard any invalid entries at the end of the array. */ 2132 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2133 npagesizes--; 2134 } 2135 2136 /* 2137 * Add the init functions from a needed object list (and its recursive 2138 * needed objects) to "list". This is not used directly; it is a helper 2139 * function for initlist_add_objects(). The write lock must be held 2140 * when this function is called. 2141 */ 2142 static void 2143 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2144 { 2145 /* Recursively process the successor needed objects. */ 2146 if (needed->next != NULL) 2147 initlist_add_neededs(needed->next, list); 2148 2149 /* Process the current needed object. */ 2150 if (needed->obj != NULL) 2151 initlist_add_objects(needed->obj, needed->obj, list); 2152 } 2153 2154 /* 2155 * Scan all of the DAGs rooted in the range of objects from "obj" to 2156 * "tail" and add their init functions to "list". This recurses over 2157 * the DAGs and ensure the proper init ordering such that each object's 2158 * needed libraries are initialized before the object itself. At the 2159 * same time, this function adds the objects to the global finalization 2160 * list "list_fini" in the opposite order. The write lock must be 2161 * held when this function is called. 2162 */ 2163 static void 2164 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2165 { 2166 Obj_Entry *nobj; 2167 2168 if (obj->init_scanned || obj->init_done) 2169 return; 2170 obj->init_scanned = true; 2171 2172 /* Recursively process the successor objects. */ 2173 nobj = globallist_next(obj); 2174 if (nobj != NULL && obj != tail) 2175 initlist_add_objects(nobj, tail, list); 2176 2177 /* Recursively process the needed objects. */ 2178 if (obj->needed != NULL) 2179 initlist_add_neededs(obj->needed, list); 2180 if (obj->needed_filtees != NULL) 2181 initlist_add_neededs(obj->needed_filtees, list); 2182 if (obj->needed_aux_filtees != NULL) 2183 initlist_add_neededs(obj->needed_aux_filtees, list); 2184 2185 /* Add the object to the init list. */ 2186 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2187 obj->init_array != (Elf_Addr)NULL) 2188 objlist_push_tail(list, obj); 2189 2190 /* Add the object to the global fini list in the reverse order. */ 2191 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2192 && !obj->on_fini_list) { 2193 objlist_push_head(&list_fini, obj); 2194 obj->on_fini_list = true; 2195 } 2196 } 2197 2198 #ifndef FPTR_TARGET 2199 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2200 #endif 2201 2202 static void 2203 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2204 { 2205 Needed_Entry *needed, *needed1; 2206 2207 for (needed = n; needed != NULL; needed = needed->next) { 2208 if (needed->obj != NULL) { 2209 dlclose_locked(needed->obj, lockstate); 2210 needed->obj = NULL; 2211 } 2212 } 2213 for (needed = n; needed != NULL; needed = needed1) { 2214 needed1 = needed->next; 2215 free(needed); 2216 } 2217 } 2218 2219 static void 2220 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2221 { 2222 2223 free_needed_filtees(obj->needed_filtees, lockstate); 2224 obj->needed_filtees = NULL; 2225 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2226 obj->needed_aux_filtees = NULL; 2227 obj->filtees_loaded = false; 2228 } 2229 2230 static void 2231 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2232 RtldLockState *lockstate) 2233 { 2234 2235 for (; needed != NULL; needed = needed->next) { 2236 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2237 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2238 RTLD_LOCAL, lockstate); 2239 } 2240 } 2241 2242 static void 2243 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2244 { 2245 2246 lock_restart_for_upgrade(lockstate); 2247 if (!obj->filtees_loaded) { 2248 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2249 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2250 obj->filtees_loaded = true; 2251 } 2252 } 2253 2254 static int 2255 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2256 { 2257 Obj_Entry *obj1; 2258 2259 for (; needed != NULL; needed = needed->next) { 2260 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2261 flags & ~RTLD_LO_NOLOAD); 2262 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2263 return (-1); 2264 } 2265 return (0); 2266 } 2267 2268 /* 2269 * Given a shared object, traverse its list of needed objects, and load 2270 * each of them. Returns 0 on success. Generates an error message and 2271 * returns -1 on failure. 2272 */ 2273 static int 2274 load_needed_objects(Obj_Entry *first, int flags) 2275 { 2276 Obj_Entry *obj; 2277 2278 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2279 if (obj->marker) 2280 continue; 2281 if (process_needed(obj, obj->needed, flags) == -1) 2282 return (-1); 2283 } 2284 return (0); 2285 } 2286 2287 static int 2288 load_preload_objects(void) 2289 { 2290 char *p = ld_preload; 2291 Obj_Entry *obj; 2292 static const char delim[] = " \t:;"; 2293 2294 if (p == NULL) 2295 return 0; 2296 2297 p += strspn(p, delim); 2298 while (*p != '\0') { 2299 size_t len = strcspn(p, delim); 2300 char savech; 2301 2302 savech = p[len]; 2303 p[len] = '\0'; 2304 obj = load_object(p, -1, NULL, 0); 2305 if (obj == NULL) 2306 return -1; /* XXX - cleanup */ 2307 obj->z_interpose = true; 2308 p[len] = savech; 2309 p += len; 2310 p += strspn(p, delim); 2311 } 2312 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2313 return 0; 2314 } 2315 2316 static const char * 2317 printable_path(const char *path) 2318 { 2319 2320 return (path == NULL ? "<unknown>" : path); 2321 } 2322 2323 /* 2324 * Load a shared object into memory, if it is not already loaded. The 2325 * object may be specified by name or by user-supplied file descriptor 2326 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2327 * duplicate is. 2328 * 2329 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2330 * on failure. 2331 */ 2332 static Obj_Entry * 2333 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2334 { 2335 Obj_Entry *obj; 2336 int fd; 2337 struct stat sb; 2338 char *path; 2339 2340 fd = -1; 2341 if (name != NULL) { 2342 TAILQ_FOREACH(obj, &obj_list, next) { 2343 if (obj->marker || obj->doomed) 2344 continue; 2345 if (object_match_name(obj, name)) 2346 return (obj); 2347 } 2348 2349 path = find_library(name, refobj, &fd); 2350 if (path == NULL) 2351 return (NULL); 2352 } else 2353 path = NULL; 2354 2355 if (fd >= 0) { 2356 /* 2357 * search_library_pathfds() opens a fresh file descriptor for the 2358 * library, so there is no need to dup(). 2359 */ 2360 } else if (fd_u == -1) { 2361 /* 2362 * If we didn't find a match by pathname, or the name is not 2363 * supplied, open the file and check again by device and inode. 2364 * This avoids false mismatches caused by multiple links or ".." 2365 * in pathnames. 2366 * 2367 * To avoid a race, we open the file and use fstat() rather than 2368 * using stat(). 2369 */ 2370 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2371 _rtld_error("Cannot open \"%s\"", path); 2372 free(path); 2373 return (NULL); 2374 } 2375 } else { 2376 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2377 if (fd == -1) { 2378 _rtld_error("Cannot dup fd"); 2379 free(path); 2380 return (NULL); 2381 } 2382 } 2383 if (fstat(fd, &sb) == -1) { 2384 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2385 close(fd); 2386 free(path); 2387 return NULL; 2388 } 2389 TAILQ_FOREACH(obj, &obj_list, next) { 2390 if (obj->marker || obj->doomed) 2391 continue; 2392 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2393 break; 2394 } 2395 if (obj != NULL && name != NULL) { 2396 object_add_name(obj, name); 2397 free(path); 2398 close(fd); 2399 return obj; 2400 } 2401 if (flags & RTLD_LO_NOLOAD) { 2402 free(path); 2403 close(fd); 2404 return (NULL); 2405 } 2406 2407 /* First use of this object, so we must map it in */ 2408 obj = do_load_object(fd, name, path, &sb, flags); 2409 if (obj == NULL) 2410 free(path); 2411 close(fd); 2412 2413 return obj; 2414 } 2415 2416 static Obj_Entry * 2417 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2418 int flags) 2419 { 2420 Obj_Entry *obj; 2421 struct statfs fs; 2422 2423 /* 2424 * but first, make sure that environment variables haven't been 2425 * used to circumvent the noexec flag on a filesystem. 2426 */ 2427 if (dangerous_ld_env) { 2428 if (fstatfs(fd, &fs) != 0) { 2429 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2430 return NULL; 2431 } 2432 if (fs.f_flags & MNT_NOEXEC) { 2433 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2434 return NULL; 2435 } 2436 } 2437 dbg("loading \"%s\"", printable_path(path)); 2438 obj = map_object(fd, printable_path(path), sbp); 2439 if (obj == NULL) 2440 return NULL; 2441 2442 /* 2443 * If DT_SONAME is present in the object, digest_dynamic2 already 2444 * added it to the object names. 2445 */ 2446 if (name != NULL) 2447 object_add_name(obj, name); 2448 obj->path = path; 2449 digest_dynamic(obj, 0); 2450 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2451 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2452 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2453 RTLD_LO_DLOPEN) { 2454 dbg("refusing to load non-loadable \"%s\"", obj->path); 2455 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2456 munmap(obj->mapbase, obj->mapsize); 2457 obj_free(obj); 2458 return (NULL); 2459 } 2460 2461 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2462 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2463 obj_count++; 2464 obj_loads++; 2465 linkmap_add(obj); /* for GDB & dlinfo() */ 2466 max_stack_flags |= obj->stack_flags; 2467 2468 dbg(" %p .. %p: %s", obj->mapbase, 2469 obj->mapbase + obj->mapsize - 1, obj->path); 2470 if (obj->textrel) 2471 dbg(" WARNING: %s has impure text", obj->path); 2472 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2473 obj->path); 2474 2475 return obj; 2476 } 2477 2478 static Obj_Entry * 2479 obj_from_addr(const void *addr) 2480 { 2481 Obj_Entry *obj; 2482 2483 TAILQ_FOREACH(obj, &obj_list, next) { 2484 if (obj->marker) 2485 continue; 2486 if (addr < (void *) obj->mapbase) 2487 continue; 2488 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2489 return obj; 2490 } 2491 return NULL; 2492 } 2493 2494 static void 2495 preinit_main(void) 2496 { 2497 Elf_Addr *preinit_addr; 2498 int index; 2499 2500 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2501 if (preinit_addr == NULL) 2502 return; 2503 2504 for (index = 0; index < obj_main->preinit_array_num; index++) { 2505 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2506 dbg("calling preinit function for %s at %p", obj_main->path, 2507 (void *)preinit_addr[index]); 2508 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2509 0, 0, obj_main->path); 2510 call_init_pointer(obj_main, preinit_addr[index]); 2511 } 2512 } 2513 } 2514 2515 /* 2516 * Call the finalization functions for each of the objects in "list" 2517 * belonging to the DAG of "root" and referenced once. If NULL "root" 2518 * is specified, every finalization function will be called regardless 2519 * of the reference count and the list elements won't be freed. All of 2520 * the objects are expected to have non-NULL fini functions. 2521 */ 2522 static void 2523 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2524 { 2525 Objlist_Entry *elm; 2526 char *saved_msg; 2527 Elf_Addr *fini_addr; 2528 int index; 2529 2530 assert(root == NULL || root->refcount == 1); 2531 2532 if (root != NULL) 2533 root->doomed = true; 2534 2535 /* 2536 * Preserve the current error message since a fini function might 2537 * call into the dynamic linker and overwrite it. 2538 */ 2539 saved_msg = errmsg_save(); 2540 do { 2541 STAILQ_FOREACH(elm, list, link) { 2542 if (root != NULL && (elm->obj->refcount != 1 || 2543 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2544 continue; 2545 /* Remove object from fini list to prevent recursive invocation. */ 2546 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2547 /* Ensure that new references cannot be acquired. */ 2548 elm->obj->doomed = true; 2549 2550 hold_object(elm->obj); 2551 lock_release(rtld_bind_lock, lockstate); 2552 /* 2553 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2554 * When this happens, DT_FINI_ARRAY is processed first. 2555 */ 2556 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2557 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2558 for (index = elm->obj->fini_array_num - 1; index >= 0; 2559 index--) { 2560 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2561 dbg("calling fini function for %s at %p", 2562 elm->obj->path, (void *)fini_addr[index]); 2563 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2564 (void *)fini_addr[index], 0, 0, elm->obj->path); 2565 call_initfini_pointer(elm->obj, fini_addr[index]); 2566 } 2567 } 2568 } 2569 if (elm->obj->fini != (Elf_Addr)NULL) { 2570 dbg("calling fini function for %s at %p", elm->obj->path, 2571 (void *)elm->obj->fini); 2572 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2573 0, 0, elm->obj->path); 2574 call_initfini_pointer(elm->obj, elm->obj->fini); 2575 } 2576 wlock_acquire(rtld_bind_lock, lockstate); 2577 unhold_object(elm->obj); 2578 /* No need to free anything if process is going down. */ 2579 if (root != NULL) 2580 free(elm); 2581 /* 2582 * We must restart the list traversal after every fini call 2583 * because a dlclose() call from the fini function or from 2584 * another thread might have modified the reference counts. 2585 */ 2586 break; 2587 } 2588 } while (elm != NULL); 2589 errmsg_restore(saved_msg); 2590 } 2591 2592 /* 2593 * Call the initialization functions for each of the objects in 2594 * "list". All of the objects are expected to have non-NULL init 2595 * functions. 2596 */ 2597 static void 2598 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2599 { 2600 Objlist_Entry *elm; 2601 Obj_Entry *obj; 2602 char *saved_msg; 2603 Elf_Addr *init_addr; 2604 int index; 2605 2606 /* 2607 * Clean init_scanned flag so that objects can be rechecked and 2608 * possibly initialized earlier if any of vectors called below 2609 * cause the change by using dlopen. 2610 */ 2611 TAILQ_FOREACH(obj, &obj_list, next) { 2612 if (obj->marker) 2613 continue; 2614 obj->init_scanned = false; 2615 } 2616 2617 /* 2618 * Preserve the current error message since an init function might 2619 * call into the dynamic linker and overwrite it. 2620 */ 2621 saved_msg = errmsg_save(); 2622 STAILQ_FOREACH(elm, list, link) { 2623 if (elm->obj->init_done) /* Initialized early. */ 2624 continue; 2625 /* 2626 * Race: other thread might try to use this object before current 2627 * one completes the initialization. Not much can be done here 2628 * without better locking. 2629 */ 2630 elm->obj->init_done = true; 2631 hold_object(elm->obj); 2632 lock_release(rtld_bind_lock, lockstate); 2633 2634 /* 2635 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2636 * When this happens, DT_INIT is processed first. 2637 */ 2638 if (elm->obj->init != (Elf_Addr)NULL) { 2639 dbg("calling init function for %s at %p", elm->obj->path, 2640 (void *)elm->obj->init); 2641 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2642 0, 0, elm->obj->path); 2643 call_initfini_pointer(elm->obj, elm->obj->init); 2644 } 2645 init_addr = (Elf_Addr *)elm->obj->init_array; 2646 if (init_addr != NULL) { 2647 for (index = 0; index < elm->obj->init_array_num; index++) { 2648 if (init_addr[index] != 0 && init_addr[index] != 1) { 2649 dbg("calling init function for %s at %p", elm->obj->path, 2650 (void *)init_addr[index]); 2651 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2652 (void *)init_addr[index], 0, 0, elm->obj->path); 2653 call_init_pointer(elm->obj, init_addr[index]); 2654 } 2655 } 2656 } 2657 wlock_acquire(rtld_bind_lock, lockstate); 2658 unhold_object(elm->obj); 2659 } 2660 errmsg_restore(saved_msg); 2661 } 2662 2663 static void 2664 objlist_clear(Objlist *list) 2665 { 2666 Objlist_Entry *elm; 2667 2668 while (!STAILQ_EMPTY(list)) { 2669 elm = STAILQ_FIRST(list); 2670 STAILQ_REMOVE_HEAD(list, link); 2671 free(elm); 2672 } 2673 } 2674 2675 static Objlist_Entry * 2676 objlist_find(Objlist *list, const Obj_Entry *obj) 2677 { 2678 Objlist_Entry *elm; 2679 2680 STAILQ_FOREACH(elm, list, link) 2681 if (elm->obj == obj) 2682 return elm; 2683 return NULL; 2684 } 2685 2686 static void 2687 objlist_init(Objlist *list) 2688 { 2689 STAILQ_INIT(list); 2690 } 2691 2692 static void 2693 objlist_push_head(Objlist *list, Obj_Entry *obj) 2694 { 2695 Objlist_Entry *elm; 2696 2697 elm = NEW(Objlist_Entry); 2698 elm->obj = obj; 2699 STAILQ_INSERT_HEAD(list, elm, link); 2700 } 2701 2702 static void 2703 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2704 { 2705 Objlist_Entry *elm; 2706 2707 elm = NEW(Objlist_Entry); 2708 elm->obj = obj; 2709 STAILQ_INSERT_TAIL(list, elm, link); 2710 } 2711 2712 static void 2713 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2714 { 2715 Objlist_Entry *elm, *listelm; 2716 2717 STAILQ_FOREACH(listelm, list, link) { 2718 if (listelm->obj == listobj) 2719 break; 2720 } 2721 elm = NEW(Objlist_Entry); 2722 elm->obj = obj; 2723 if (listelm != NULL) 2724 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2725 else 2726 STAILQ_INSERT_TAIL(list, elm, link); 2727 } 2728 2729 static void 2730 objlist_remove(Objlist *list, Obj_Entry *obj) 2731 { 2732 Objlist_Entry *elm; 2733 2734 if ((elm = objlist_find(list, obj)) != NULL) { 2735 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2736 free(elm); 2737 } 2738 } 2739 2740 /* 2741 * Relocate dag rooted in the specified object. 2742 * Returns 0 on success, or -1 on failure. 2743 */ 2744 2745 static int 2746 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2747 int flags, RtldLockState *lockstate) 2748 { 2749 Objlist_Entry *elm; 2750 int error; 2751 2752 error = 0; 2753 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2754 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2755 lockstate); 2756 if (error == -1) 2757 break; 2758 } 2759 return (error); 2760 } 2761 2762 /* 2763 * Prepare for, or clean after, relocating an object marked with 2764 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2765 * segments are remapped read-write. After relocations are done, the 2766 * segment's permissions are returned back to the modes specified in 2767 * the phdrs. If any relocation happened, or always for wired 2768 * program, COW is triggered. 2769 */ 2770 static int 2771 reloc_textrel_prot(Obj_Entry *obj, bool before) 2772 { 2773 const Elf_Phdr *ph; 2774 void *base; 2775 size_t l, sz; 2776 int prot; 2777 2778 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2779 l--, ph++) { 2780 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2781 continue; 2782 base = obj->relocbase + trunc_page(ph->p_vaddr); 2783 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2784 trunc_page(ph->p_vaddr); 2785 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2786 if (mprotect(base, sz, prot) == -1) { 2787 _rtld_error("%s: Cannot write-%sable text segment: %s", 2788 obj->path, before ? "en" : "dis", 2789 rtld_strerror(errno)); 2790 return (-1); 2791 } 2792 } 2793 return (0); 2794 } 2795 2796 /* 2797 * Relocate single object. 2798 * Returns 0 on success, or -1 on failure. 2799 */ 2800 static int 2801 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2802 int flags, RtldLockState *lockstate) 2803 { 2804 2805 if (obj->relocated) 2806 return (0); 2807 obj->relocated = true; 2808 if (obj != rtldobj) 2809 dbg("relocating \"%s\"", obj->path); 2810 2811 if (obj->symtab == NULL || obj->strtab == NULL || 2812 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2813 _rtld_error("%s: Shared object has no run-time symbol table", 2814 obj->path); 2815 return (-1); 2816 } 2817 2818 /* There are relocations to the write-protected text segment. */ 2819 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2820 return (-1); 2821 2822 /* Process the non-PLT non-IFUNC relocations. */ 2823 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2824 return (-1); 2825 2826 /* Re-protected the text segment. */ 2827 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2828 return (-1); 2829 2830 /* Set the special PLT or GOT entries. */ 2831 init_pltgot(obj); 2832 2833 /* Process the PLT relocations. */ 2834 if (reloc_plt(obj) == -1) 2835 return (-1); 2836 /* Relocate the jump slots if we are doing immediate binding. */ 2837 if (obj->bind_now || bind_now) 2838 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2839 return (-1); 2840 2841 /* 2842 * Process the non-PLT IFUNC relocations. The relocations are 2843 * processed in two phases, because IFUNC resolvers may 2844 * reference other symbols, which must be readily processed 2845 * before resolvers are called. 2846 */ 2847 if (obj->non_plt_gnu_ifunc && 2848 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2849 return (-1); 2850 2851 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2852 return (-1); 2853 2854 /* 2855 * Set up the magic number and version in the Obj_Entry. These 2856 * were checked in the crt1.o from the original ElfKit, so we 2857 * set them for backward compatibility. 2858 */ 2859 obj->magic = RTLD_MAGIC; 2860 obj->version = RTLD_VERSION; 2861 2862 return (0); 2863 } 2864 2865 /* 2866 * Relocate newly-loaded shared objects. The argument is a pointer to 2867 * the Obj_Entry for the first such object. All objects from the first 2868 * to the end of the list of objects are relocated. Returns 0 on success, 2869 * or -1 on failure. 2870 */ 2871 static int 2872 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2873 int flags, RtldLockState *lockstate) 2874 { 2875 Obj_Entry *obj; 2876 int error; 2877 2878 for (error = 0, obj = first; obj != NULL; 2879 obj = TAILQ_NEXT(obj, next)) { 2880 if (obj->marker) 2881 continue; 2882 error = relocate_object(obj, bind_now, rtldobj, flags, 2883 lockstate); 2884 if (error == -1) 2885 break; 2886 } 2887 return (error); 2888 } 2889 2890 /* 2891 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2892 * referencing STT_GNU_IFUNC symbols is postponed till the other 2893 * relocations are done. The indirect functions specified as 2894 * ifunc are allowed to call other symbols, so we need to have 2895 * objects relocated before asking for resolution from indirects. 2896 * 2897 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2898 * instead of the usual lazy handling of PLT slots. It is 2899 * consistent with how GNU does it. 2900 */ 2901 static int 2902 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2903 RtldLockState *lockstate) 2904 { 2905 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2906 return (-1); 2907 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2908 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2909 return (-1); 2910 return (0); 2911 } 2912 2913 static int 2914 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2915 RtldLockState *lockstate) 2916 { 2917 Obj_Entry *obj; 2918 2919 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2920 if (obj->marker) 2921 continue; 2922 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2923 return (-1); 2924 } 2925 return (0); 2926 } 2927 2928 static int 2929 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2930 RtldLockState *lockstate) 2931 { 2932 Objlist_Entry *elm; 2933 2934 STAILQ_FOREACH(elm, list, link) { 2935 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2936 lockstate) == -1) 2937 return (-1); 2938 } 2939 return (0); 2940 } 2941 2942 /* 2943 * Cleanup procedure. It will be called (by the atexit mechanism) just 2944 * before the process exits. 2945 */ 2946 static void 2947 rtld_exit(void) 2948 { 2949 RtldLockState lockstate; 2950 2951 wlock_acquire(rtld_bind_lock, &lockstate); 2952 dbg("rtld_exit()"); 2953 objlist_call_fini(&list_fini, NULL, &lockstate); 2954 /* No need to remove the items from the list, since we are exiting. */ 2955 if (!libmap_disable) 2956 lm_fini(); 2957 lock_release(rtld_bind_lock, &lockstate); 2958 } 2959 2960 /* 2961 * Iterate over a search path, translate each element, and invoke the 2962 * callback on the result. 2963 */ 2964 static void * 2965 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2966 { 2967 const char *trans; 2968 if (path == NULL) 2969 return (NULL); 2970 2971 path += strspn(path, ":;"); 2972 while (*path != '\0') { 2973 size_t len; 2974 char *res; 2975 2976 len = strcspn(path, ":;"); 2977 trans = lm_findn(NULL, path, len); 2978 if (trans) 2979 res = callback(trans, strlen(trans), arg); 2980 else 2981 res = callback(path, len, arg); 2982 2983 if (res != NULL) 2984 return (res); 2985 2986 path += len; 2987 path += strspn(path, ":;"); 2988 } 2989 2990 return (NULL); 2991 } 2992 2993 struct try_library_args { 2994 const char *name; 2995 size_t namelen; 2996 char *buffer; 2997 size_t buflen; 2998 }; 2999 3000 static void * 3001 try_library_path(const char *dir, size_t dirlen, void *param) 3002 { 3003 struct try_library_args *arg; 3004 3005 arg = param; 3006 if (*dir == '/' || trust) { 3007 char *pathname; 3008 3009 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3010 return (NULL); 3011 3012 pathname = arg->buffer; 3013 strncpy(pathname, dir, dirlen); 3014 pathname[dirlen] = '/'; 3015 strcpy(pathname + dirlen + 1, arg->name); 3016 3017 dbg(" Trying \"%s\"", pathname); 3018 if (access(pathname, F_OK) == 0) { /* We found it */ 3019 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3020 strcpy(pathname, arg->buffer); 3021 return (pathname); 3022 } 3023 } 3024 return (NULL); 3025 } 3026 3027 static char * 3028 search_library_path(const char *name, const char *path) 3029 { 3030 char *p; 3031 struct try_library_args arg; 3032 3033 if (path == NULL) 3034 return NULL; 3035 3036 arg.name = name; 3037 arg.namelen = strlen(name); 3038 arg.buffer = xmalloc(PATH_MAX); 3039 arg.buflen = PATH_MAX; 3040 3041 p = path_enumerate(path, try_library_path, &arg); 3042 3043 free(arg.buffer); 3044 3045 return (p); 3046 } 3047 3048 3049 /* 3050 * Finds the library with the given name using the directory descriptors 3051 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3052 * 3053 * Returns a freshly-opened close-on-exec file descriptor for the library, 3054 * or -1 if the library cannot be found. 3055 */ 3056 static char * 3057 search_library_pathfds(const char *name, const char *path, int *fdp) 3058 { 3059 char *envcopy, *fdstr, *found, *last_token; 3060 size_t len; 3061 int dirfd, fd; 3062 3063 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3064 3065 /* Don't load from user-specified libdirs into setuid binaries. */ 3066 if (!trust) 3067 return (NULL); 3068 3069 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3070 if (path == NULL) 3071 return (NULL); 3072 3073 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3074 if (name[0] == '/') { 3075 dbg("Absolute path (%s) passed to %s", name, __func__); 3076 return (NULL); 3077 } 3078 3079 /* 3080 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3081 * copy of the path, as strtok_r rewrites separator tokens 3082 * with '\0'. 3083 */ 3084 found = NULL; 3085 envcopy = xstrdup(path); 3086 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3087 fdstr = strtok_r(NULL, ":", &last_token)) { 3088 dirfd = parse_integer(fdstr); 3089 if (dirfd < 0) { 3090 _rtld_error("failed to parse directory FD: '%s'", 3091 fdstr); 3092 break; 3093 } 3094 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3095 if (fd >= 0) { 3096 *fdp = fd; 3097 len = strlen(fdstr) + strlen(name) + 3; 3098 found = xmalloc(len); 3099 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3100 _rtld_error("error generating '%d/%s'", 3101 dirfd, name); 3102 rtld_die(); 3103 } 3104 dbg("open('%s') => %d", found, fd); 3105 break; 3106 } 3107 } 3108 free(envcopy); 3109 3110 return (found); 3111 } 3112 3113 3114 int 3115 dlclose(void *handle) 3116 { 3117 RtldLockState lockstate; 3118 int error; 3119 3120 wlock_acquire(rtld_bind_lock, &lockstate); 3121 error = dlclose_locked(handle, &lockstate); 3122 lock_release(rtld_bind_lock, &lockstate); 3123 return (error); 3124 } 3125 3126 static int 3127 dlclose_locked(void *handle, RtldLockState *lockstate) 3128 { 3129 Obj_Entry *root; 3130 3131 root = dlcheck(handle); 3132 if (root == NULL) 3133 return -1; 3134 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3135 root->path); 3136 3137 /* Unreference the object and its dependencies. */ 3138 root->dl_refcount--; 3139 3140 if (root->refcount == 1) { 3141 /* 3142 * The object will be no longer referenced, so we must unload it. 3143 * First, call the fini functions. 3144 */ 3145 objlist_call_fini(&list_fini, root, lockstate); 3146 3147 unref_dag(root); 3148 3149 /* Finish cleaning up the newly-unreferenced objects. */ 3150 GDB_STATE(RT_DELETE,&root->linkmap); 3151 unload_object(root, lockstate); 3152 GDB_STATE(RT_CONSISTENT,NULL); 3153 } else 3154 unref_dag(root); 3155 3156 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3157 return 0; 3158 } 3159 3160 char * 3161 dlerror(void) 3162 { 3163 char *msg = error_message; 3164 error_message = NULL; 3165 return msg; 3166 } 3167 3168 /* 3169 * This function is deprecated and has no effect. 3170 */ 3171 void 3172 dllockinit(void *context, 3173 void *(*lock_create)(void *context), 3174 void (*rlock_acquire)(void *lock), 3175 void (*wlock_acquire)(void *lock), 3176 void (*lock_release)(void *lock), 3177 void (*lock_destroy)(void *lock), 3178 void (*context_destroy)(void *context)) 3179 { 3180 static void *cur_context; 3181 static void (*cur_context_destroy)(void *); 3182 3183 /* Just destroy the context from the previous call, if necessary. */ 3184 if (cur_context_destroy != NULL) 3185 cur_context_destroy(cur_context); 3186 cur_context = context; 3187 cur_context_destroy = context_destroy; 3188 } 3189 3190 void * 3191 dlopen(const char *name, int mode) 3192 { 3193 3194 return (rtld_dlopen(name, -1, mode)); 3195 } 3196 3197 void * 3198 fdlopen(int fd, int mode) 3199 { 3200 3201 return (rtld_dlopen(NULL, fd, mode)); 3202 } 3203 3204 static void * 3205 rtld_dlopen(const char *name, int fd, int mode) 3206 { 3207 RtldLockState lockstate; 3208 int lo_flags; 3209 3210 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3211 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3212 if (ld_tracing != NULL) { 3213 rlock_acquire(rtld_bind_lock, &lockstate); 3214 if (sigsetjmp(lockstate.env, 0) != 0) 3215 lock_upgrade(rtld_bind_lock, &lockstate); 3216 environ = (char **)*get_program_var_addr("environ", &lockstate); 3217 lock_release(rtld_bind_lock, &lockstate); 3218 } 3219 lo_flags = RTLD_LO_DLOPEN; 3220 if (mode & RTLD_NODELETE) 3221 lo_flags |= RTLD_LO_NODELETE; 3222 if (mode & RTLD_NOLOAD) 3223 lo_flags |= RTLD_LO_NOLOAD; 3224 if (ld_tracing != NULL) 3225 lo_flags |= RTLD_LO_TRACE; 3226 3227 return (dlopen_object(name, fd, obj_main, lo_flags, 3228 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3229 } 3230 3231 static void 3232 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3233 { 3234 3235 obj->dl_refcount--; 3236 unref_dag(obj); 3237 if (obj->refcount == 0) 3238 unload_object(obj, lockstate); 3239 } 3240 3241 static Obj_Entry * 3242 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3243 int mode, RtldLockState *lockstate) 3244 { 3245 Obj_Entry *old_obj_tail; 3246 Obj_Entry *obj; 3247 Objlist initlist; 3248 RtldLockState mlockstate; 3249 int result; 3250 3251 objlist_init(&initlist); 3252 3253 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3254 wlock_acquire(rtld_bind_lock, &mlockstate); 3255 lockstate = &mlockstate; 3256 } 3257 GDB_STATE(RT_ADD,NULL); 3258 3259 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3260 obj = NULL; 3261 if (name == NULL && fd == -1) { 3262 obj = obj_main; 3263 obj->refcount++; 3264 } else { 3265 obj = load_object(name, fd, refobj, lo_flags); 3266 } 3267 3268 if (obj) { 3269 obj->dl_refcount++; 3270 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3271 objlist_push_tail(&list_global, obj); 3272 if (globallist_next(old_obj_tail) != NULL) { 3273 /* We loaded something new. */ 3274 assert(globallist_next(old_obj_tail) == obj); 3275 result = load_needed_objects(obj, 3276 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3277 init_dag(obj); 3278 ref_dag(obj); 3279 if (result != -1) 3280 result = rtld_verify_versions(&obj->dagmembers); 3281 if (result != -1 && ld_tracing) 3282 goto trace; 3283 if (result == -1 || relocate_object_dag(obj, 3284 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3285 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3286 lockstate) == -1) { 3287 dlopen_cleanup(obj, lockstate); 3288 obj = NULL; 3289 } else if (lo_flags & RTLD_LO_EARLY) { 3290 /* 3291 * Do not call the init functions for early loaded 3292 * filtees. The image is still not initialized enough 3293 * for them to work. 3294 * 3295 * Our object is found by the global object list and 3296 * will be ordered among all init calls done right 3297 * before transferring control to main. 3298 */ 3299 } else { 3300 /* Make list of init functions to call. */ 3301 initlist_add_objects(obj, obj, &initlist); 3302 } 3303 /* 3304 * Process all no_delete or global objects here, given 3305 * them own DAGs to prevent their dependencies from being 3306 * unloaded. This has to be done after we have loaded all 3307 * of the dependencies, so that we do not miss any. 3308 */ 3309 if (obj != NULL) 3310 process_z(obj); 3311 } else { 3312 /* 3313 * Bump the reference counts for objects on this DAG. If 3314 * this is the first dlopen() call for the object that was 3315 * already loaded as a dependency, initialize the dag 3316 * starting at it. 3317 */ 3318 init_dag(obj); 3319 ref_dag(obj); 3320 3321 if ((lo_flags & RTLD_LO_TRACE) != 0) 3322 goto trace; 3323 } 3324 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3325 obj->z_nodelete) && !obj->ref_nodel) { 3326 dbg("obj %s nodelete", obj->path); 3327 ref_dag(obj); 3328 obj->z_nodelete = obj->ref_nodel = true; 3329 } 3330 } 3331 3332 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3333 name); 3334 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3335 3336 if (!(lo_flags & RTLD_LO_EARLY)) { 3337 map_stacks_exec(lockstate); 3338 } 3339 3340 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3341 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3342 lockstate) == -1) { 3343 objlist_clear(&initlist); 3344 dlopen_cleanup(obj, lockstate); 3345 if (lockstate == &mlockstate) 3346 lock_release(rtld_bind_lock, lockstate); 3347 return (NULL); 3348 } 3349 3350 if (!(lo_flags & RTLD_LO_EARLY)) { 3351 /* Call the init functions. */ 3352 objlist_call_init(&initlist, lockstate); 3353 } 3354 objlist_clear(&initlist); 3355 if (lockstate == &mlockstate) 3356 lock_release(rtld_bind_lock, lockstate); 3357 return obj; 3358 trace: 3359 trace_loaded_objects(obj); 3360 if (lockstate == &mlockstate) 3361 lock_release(rtld_bind_lock, lockstate); 3362 exit(0); 3363 } 3364 3365 static void * 3366 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3367 int flags) 3368 { 3369 DoneList donelist; 3370 const Obj_Entry *obj, *defobj; 3371 const Elf_Sym *def; 3372 SymLook req; 3373 RtldLockState lockstate; 3374 tls_index ti; 3375 void *sym; 3376 int res; 3377 3378 def = NULL; 3379 defobj = NULL; 3380 symlook_init(&req, name); 3381 req.ventry = ve; 3382 req.flags = flags | SYMLOOK_IN_PLT; 3383 req.lockstate = &lockstate; 3384 3385 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3386 rlock_acquire(rtld_bind_lock, &lockstate); 3387 if (sigsetjmp(lockstate.env, 0) != 0) 3388 lock_upgrade(rtld_bind_lock, &lockstate); 3389 if (handle == NULL || handle == RTLD_NEXT || 3390 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3391 3392 if ((obj = obj_from_addr(retaddr)) == NULL) { 3393 _rtld_error("Cannot determine caller's shared object"); 3394 lock_release(rtld_bind_lock, &lockstate); 3395 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3396 return NULL; 3397 } 3398 if (handle == NULL) { /* Just the caller's shared object. */ 3399 res = symlook_obj(&req, obj); 3400 if (res == 0) { 3401 def = req.sym_out; 3402 defobj = req.defobj_out; 3403 } 3404 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3405 handle == RTLD_SELF) { /* ... caller included */ 3406 if (handle == RTLD_NEXT) 3407 obj = globallist_next(obj); 3408 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3409 if (obj->marker) 3410 continue; 3411 res = symlook_obj(&req, obj); 3412 if (res == 0) { 3413 if (def == NULL || 3414 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3415 def = req.sym_out; 3416 defobj = req.defobj_out; 3417 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3418 break; 3419 } 3420 } 3421 } 3422 /* 3423 * Search the dynamic linker itself, and possibly resolve the 3424 * symbol from there. This is how the application links to 3425 * dynamic linker services such as dlopen. 3426 */ 3427 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3428 res = symlook_obj(&req, &obj_rtld); 3429 if (res == 0) { 3430 def = req.sym_out; 3431 defobj = req.defobj_out; 3432 } 3433 } 3434 } else { 3435 assert(handle == RTLD_DEFAULT); 3436 res = symlook_default(&req, obj); 3437 if (res == 0) { 3438 defobj = req.defobj_out; 3439 def = req.sym_out; 3440 } 3441 } 3442 } else { 3443 if ((obj = dlcheck(handle)) == NULL) { 3444 lock_release(rtld_bind_lock, &lockstate); 3445 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3446 return NULL; 3447 } 3448 3449 donelist_init(&donelist); 3450 if (obj->mainprog) { 3451 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3452 res = symlook_global(&req, &donelist); 3453 if (res == 0) { 3454 def = req.sym_out; 3455 defobj = req.defobj_out; 3456 } 3457 /* 3458 * Search the dynamic linker itself, and possibly resolve the 3459 * symbol from there. This is how the application links to 3460 * dynamic linker services such as dlopen. 3461 */ 3462 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3463 res = symlook_obj(&req, &obj_rtld); 3464 if (res == 0) { 3465 def = req.sym_out; 3466 defobj = req.defobj_out; 3467 } 3468 } 3469 } 3470 else { 3471 /* Search the whole DAG rooted at the given object. */ 3472 res = symlook_list(&req, &obj->dagmembers, &donelist); 3473 if (res == 0) { 3474 def = req.sym_out; 3475 defobj = req.defobj_out; 3476 } 3477 } 3478 } 3479 3480 if (def != NULL) { 3481 lock_release(rtld_bind_lock, &lockstate); 3482 3483 /* 3484 * The value required by the caller is derived from the value 3485 * of the symbol. this is simply the relocated value of the 3486 * symbol. 3487 */ 3488 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3489 sym = make_function_pointer(def, defobj); 3490 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3491 sym = rtld_resolve_ifunc(defobj, def); 3492 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3493 ti.ti_module = defobj->tlsindex; 3494 ti.ti_offset = def->st_value; 3495 sym = __tls_get_addr(&ti); 3496 } else 3497 sym = defobj->relocbase + def->st_value; 3498 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3499 return (sym); 3500 } 3501 3502 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3503 ve != NULL ? ve->name : ""); 3504 lock_release(rtld_bind_lock, &lockstate); 3505 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3506 return NULL; 3507 } 3508 3509 void * 3510 dlsym(void *handle, const char *name) 3511 { 3512 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3513 SYMLOOK_DLSYM); 3514 } 3515 3516 dlfunc_t 3517 dlfunc(void *handle, const char *name) 3518 { 3519 union { 3520 void *d; 3521 dlfunc_t f; 3522 } rv; 3523 3524 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3525 SYMLOOK_DLSYM); 3526 return (rv.f); 3527 } 3528 3529 void * 3530 dlvsym(void *handle, const char *name, const char *version) 3531 { 3532 Ver_Entry ventry; 3533 3534 ventry.name = version; 3535 ventry.file = NULL; 3536 ventry.hash = elf_hash(version); 3537 ventry.flags= 0; 3538 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3539 SYMLOOK_DLSYM); 3540 } 3541 3542 int 3543 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3544 { 3545 const Obj_Entry *obj; 3546 RtldLockState lockstate; 3547 3548 rlock_acquire(rtld_bind_lock, &lockstate); 3549 obj = obj_from_addr(addr); 3550 if (obj == NULL) { 3551 _rtld_error("No shared object contains address"); 3552 lock_release(rtld_bind_lock, &lockstate); 3553 return (0); 3554 } 3555 rtld_fill_dl_phdr_info(obj, phdr_info); 3556 lock_release(rtld_bind_lock, &lockstate); 3557 return (1); 3558 } 3559 3560 int 3561 dladdr(const void *addr, Dl_info *info) 3562 { 3563 const Obj_Entry *obj; 3564 const Elf_Sym *def; 3565 void *symbol_addr; 3566 unsigned long symoffset; 3567 RtldLockState lockstate; 3568 3569 rlock_acquire(rtld_bind_lock, &lockstate); 3570 obj = obj_from_addr(addr); 3571 if (obj == NULL) { 3572 _rtld_error("No shared object contains address"); 3573 lock_release(rtld_bind_lock, &lockstate); 3574 return 0; 3575 } 3576 info->dli_fname = obj->path; 3577 info->dli_fbase = obj->mapbase; 3578 info->dli_saddr = (void *)0; 3579 info->dli_sname = NULL; 3580 3581 /* 3582 * Walk the symbol list looking for the symbol whose address is 3583 * closest to the address sent in. 3584 */ 3585 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3586 def = obj->symtab + symoffset; 3587 3588 /* 3589 * For skip the symbol if st_shndx is either SHN_UNDEF or 3590 * SHN_COMMON. 3591 */ 3592 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3593 continue; 3594 3595 /* 3596 * If the symbol is greater than the specified address, or if it 3597 * is further away from addr than the current nearest symbol, 3598 * then reject it. 3599 */ 3600 symbol_addr = obj->relocbase + def->st_value; 3601 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3602 continue; 3603 3604 /* Update our idea of the nearest symbol. */ 3605 info->dli_sname = obj->strtab + def->st_name; 3606 info->dli_saddr = symbol_addr; 3607 3608 /* Exact match? */ 3609 if (info->dli_saddr == addr) 3610 break; 3611 } 3612 lock_release(rtld_bind_lock, &lockstate); 3613 return 1; 3614 } 3615 3616 int 3617 dlinfo(void *handle, int request, void *p) 3618 { 3619 const Obj_Entry *obj; 3620 RtldLockState lockstate; 3621 int error; 3622 3623 rlock_acquire(rtld_bind_lock, &lockstate); 3624 3625 if (handle == NULL || handle == RTLD_SELF) { 3626 void *retaddr; 3627 3628 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3629 if ((obj = obj_from_addr(retaddr)) == NULL) 3630 _rtld_error("Cannot determine caller's shared object"); 3631 } else 3632 obj = dlcheck(handle); 3633 3634 if (obj == NULL) { 3635 lock_release(rtld_bind_lock, &lockstate); 3636 return (-1); 3637 } 3638 3639 error = 0; 3640 switch (request) { 3641 case RTLD_DI_LINKMAP: 3642 *((struct link_map const **)p) = &obj->linkmap; 3643 break; 3644 case RTLD_DI_ORIGIN: 3645 error = rtld_dirname(obj->path, p); 3646 break; 3647 3648 case RTLD_DI_SERINFOSIZE: 3649 case RTLD_DI_SERINFO: 3650 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3651 break; 3652 3653 default: 3654 _rtld_error("Invalid request %d passed to dlinfo()", request); 3655 error = -1; 3656 } 3657 3658 lock_release(rtld_bind_lock, &lockstate); 3659 3660 return (error); 3661 } 3662 3663 static void 3664 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3665 { 3666 3667 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3668 phdr_info->dlpi_name = obj->path; 3669 phdr_info->dlpi_phdr = obj->phdr; 3670 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3671 phdr_info->dlpi_tls_modid = obj->tlsindex; 3672 phdr_info->dlpi_tls_data = obj->tlsinit; 3673 phdr_info->dlpi_adds = obj_loads; 3674 phdr_info->dlpi_subs = obj_loads - obj_count; 3675 } 3676 3677 int 3678 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3679 { 3680 struct dl_phdr_info phdr_info; 3681 Obj_Entry *obj, marker; 3682 RtldLockState bind_lockstate, phdr_lockstate; 3683 int error; 3684 3685 init_marker(&marker); 3686 error = 0; 3687 3688 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3689 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3690 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3691 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3692 rtld_fill_dl_phdr_info(obj, &phdr_info); 3693 hold_object(obj); 3694 lock_release(rtld_bind_lock, &bind_lockstate); 3695 3696 error = callback(&phdr_info, sizeof phdr_info, param); 3697 3698 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3699 unhold_object(obj); 3700 obj = globallist_next(&marker); 3701 TAILQ_REMOVE(&obj_list, &marker, next); 3702 if (error != 0) { 3703 lock_release(rtld_bind_lock, &bind_lockstate); 3704 lock_release(rtld_phdr_lock, &phdr_lockstate); 3705 return (error); 3706 } 3707 } 3708 3709 if (error == 0) { 3710 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3711 lock_release(rtld_bind_lock, &bind_lockstate); 3712 error = callback(&phdr_info, sizeof(phdr_info), param); 3713 } 3714 lock_release(rtld_phdr_lock, &phdr_lockstate); 3715 return (error); 3716 } 3717 3718 static void * 3719 fill_search_info(const char *dir, size_t dirlen, void *param) 3720 { 3721 struct fill_search_info_args *arg; 3722 3723 arg = param; 3724 3725 if (arg->request == RTLD_DI_SERINFOSIZE) { 3726 arg->serinfo->dls_cnt ++; 3727 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3728 } else { 3729 struct dl_serpath *s_entry; 3730 3731 s_entry = arg->serpath; 3732 s_entry->dls_name = arg->strspace; 3733 s_entry->dls_flags = arg->flags; 3734 3735 strncpy(arg->strspace, dir, dirlen); 3736 arg->strspace[dirlen] = '\0'; 3737 3738 arg->strspace += dirlen + 1; 3739 arg->serpath++; 3740 } 3741 3742 return (NULL); 3743 } 3744 3745 static int 3746 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3747 { 3748 struct dl_serinfo _info; 3749 struct fill_search_info_args args; 3750 3751 args.request = RTLD_DI_SERINFOSIZE; 3752 args.serinfo = &_info; 3753 3754 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3755 _info.dls_cnt = 0; 3756 3757 path_enumerate(obj->rpath, fill_search_info, &args); 3758 path_enumerate(ld_library_path, fill_search_info, &args); 3759 path_enumerate(obj->runpath, fill_search_info, &args); 3760 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3761 if (!obj->z_nodeflib) 3762 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3763 3764 3765 if (request == RTLD_DI_SERINFOSIZE) { 3766 info->dls_size = _info.dls_size; 3767 info->dls_cnt = _info.dls_cnt; 3768 return (0); 3769 } 3770 3771 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3772 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3773 return (-1); 3774 } 3775 3776 args.request = RTLD_DI_SERINFO; 3777 args.serinfo = info; 3778 args.serpath = &info->dls_serpath[0]; 3779 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3780 3781 args.flags = LA_SER_RUNPATH; 3782 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3783 return (-1); 3784 3785 args.flags = LA_SER_LIBPATH; 3786 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3787 return (-1); 3788 3789 args.flags = LA_SER_RUNPATH; 3790 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3791 return (-1); 3792 3793 args.flags = LA_SER_CONFIG; 3794 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3795 != NULL) 3796 return (-1); 3797 3798 args.flags = LA_SER_DEFAULT; 3799 if (!obj->z_nodeflib && 3800 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3801 return (-1); 3802 return (0); 3803 } 3804 3805 static int 3806 rtld_dirname(const char *path, char *bname) 3807 { 3808 const char *endp; 3809 3810 /* Empty or NULL string gets treated as "." */ 3811 if (path == NULL || *path == '\0') { 3812 bname[0] = '.'; 3813 bname[1] = '\0'; 3814 return (0); 3815 } 3816 3817 /* Strip trailing slashes */ 3818 endp = path + strlen(path) - 1; 3819 while (endp > path && *endp == '/') 3820 endp--; 3821 3822 /* Find the start of the dir */ 3823 while (endp > path && *endp != '/') 3824 endp--; 3825 3826 /* Either the dir is "/" or there are no slashes */ 3827 if (endp == path) { 3828 bname[0] = *endp == '/' ? '/' : '.'; 3829 bname[1] = '\0'; 3830 return (0); 3831 } else { 3832 do { 3833 endp--; 3834 } while (endp > path && *endp == '/'); 3835 } 3836 3837 if (endp - path + 2 > PATH_MAX) 3838 { 3839 _rtld_error("Filename is too long: %s", path); 3840 return(-1); 3841 } 3842 3843 strncpy(bname, path, endp - path + 1); 3844 bname[endp - path + 1] = '\0'; 3845 return (0); 3846 } 3847 3848 static int 3849 rtld_dirname_abs(const char *path, char *base) 3850 { 3851 char *last; 3852 3853 if (realpath(path, base) == NULL) 3854 return (-1); 3855 dbg("%s -> %s", path, base); 3856 last = strrchr(base, '/'); 3857 if (last == NULL) 3858 return (-1); 3859 if (last != base) 3860 *last = '\0'; 3861 return (0); 3862 } 3863 3864 static void 3865 linkmap_add(Obj_Entry *obj) 3866 { 3867 struct link_map *l = &obj->linkmap; 3868 struct link_map *prev; 3869 3870 obj->linkmap.l_name = obj->path; 3871 obj->linkmap.l_addr = obj->mapbase; 3872 obj->linkmap.l_ld = obj->dynamic; 3873 #ifdef __mips__ 3874 /* GDB needs load offset on MIPS to use the symbols */ 3875 obj->linkmap.l_offs = obj->relocbase; 3876 #endif 3877 3878 if (r_debug.r_map == NULL) { 3879 r_debug.r_map = l; 3880 return; 3881 } 3882 3883 /* 3884 * Scan to the end of the list, but not past the entry for the 3885 * dynamic linker, which we want to keep at the very end. 3886 */ 3887 for (prev = r_debug.r_map; 3888 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3889 prev = prev->l_next) 3890 ; 3891 3892 /* Link in the new entry. */ 3893 l->l_prev = prev; 3894 l->l_next = prev->l_next; 3895 if (l->l_next != NULL) 3896 l->l_next->l_prev = l; 3897 prev->l_next = l; 3898 } 3899 3900 static void 3901 linkmap_delete(Obj_Entry *obj) 3902 { 3903 struct link_map *l = &obj->linkmap; 3904 3905 if (l->l_prev == NULL) { 3906 if ((r_debug.r_map = l->l_next) != NULL) 3907 l->l_next->l_prev = NULL; 3908 return; 3909 } 3910 3911 if ((l->l_prev->l_next = l->l_next) != NULL) 3912 l->l_next->l_prev = l->l_prev; 3913 } 3914 3915 /* 3916 * Function for the debugger to set a breakpoint on to gain control. 3917 * 3918 * The two parameters allow the debugger to easily find and determine 3919 * what the runtime loader is doing and to whom it is doing it. 3920 * 3921 * When the loadhook trap is hit (r_debug_state, set at program 3922 * initialization), the arguments can be found on the stack: 3923 * 3924 * +8 struct link_map *m 3925 * +4 struct r_debug *rd 3926 * +0 RetAddr 3927 */ 3928 void 3929 r_debug_state(struct r_debug* rd, struct link_map *m) 3930 { 3931 /* 3932 * The following is a hack to force the compiler to emit calls to 3933 * this function, even when optimizing. If the function is empty, 3934 * the compiler is not obliged to emit any code for calls to it, 3935 * even when marked __noinline. However, gdb depends on those 3936 * calls being made. 3937 */ 3938 __compiler_membar(); 3939 } 3940 3941 /* 3942 * A function called after init routines have completed. This can be used to 3943 * break before a program's entry routine is called, and can be used when 3944 * main is not available in the symbol table. 3945 */ 3946 void 3947 _r_debug_postinit(struct link_map *m) 3948 { 3949 3950 /* See r_debug_state(). */ 3951 __compiler_membar(); 3952 } 3953 3954 static void 3955 release_object(Obj_Entry *obj) 3956 { 3957 3958 if (obj->holdcount > 0) { 3959 obj->unholdfree = true; 3960 return; 3961 } 3962 munmap(obj->mapbase, obj->mapsize); 3963 linkmap_delete(obj); 3964 obj_free(obj); 3965 } 3966 3967 /* 3968 * Get address of the pointer variable in the main program. 3969 * Prefer non-weak symbol over the weak one. 3970 */ 3971 static const void ** 3972 get_program_var_addr(const char *name, RtldLockState *lockstate) 3973 { 3974 SymLook req; 3975 DoneList donelist; 3976 3977 symlook_init(&req, name); 3978 req.lockstate = lockstate; 3979 donelist_init(&donelist); 3980 if (symlook_global(&req, &donelist) != 0) 3981 return (NULL); 3982 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3983 return ((const void **)make_function_pointer(req.sym_out, 3984 req.defobj_out)); 3985 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3986 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3987 else 3988 return ((const void **)(req.defobj_out->relocbase + 3989 req.sym_out->st_value)); 3990 } 3991 3992 /* 3993 * Set a pointer variable in the main program to the given value. This 3994 * is used to set key variables such as "environ" before any of the 3995 * init functions are called. 3996 */ 3997 static void 3998 set_program_var(const char *name, const void *value) 3999 { 4000 const void **addr; 4001 4002 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4003 dbg("\"%s\": *%p <-- %p", name, addr, value); 4004 *addr = value; 4005 } 4006 } 4007 4008 /* 4009 * Search the global objects, including dependencies and main object, 4010 * for the given symbol. 4011 */ 4012 static int 4013 symlook_global(SymLook *req, DoneList *donelist) 4014 { 4015 SymLook req1; 4016 const Objlist_Entry *elm; 4017 int res; 4018 4019 symlook_init_from_req(&req1, req); 4020 4021 /* Search all objects loaded at program start up. */ 4022 if (req->defobj_out == NULL || 4023 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4024 res = symlook_list(&req1, &list_main, donelist); 4025 if (res == 0 && (req->defobj_out == NULL || 4026 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4027 req->sym_out = req1.sym_out; 4028 req->defobj_out = req1.defobj_out; 4029 assert(req->defobj_out != NULL); 4030 } 4031 } 4032 4033 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4034 STAILQ_FOREACH(elm, &list_global, link) { 4035 if (req->defobj_out != NULL && 4036 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4037 break; 4038 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4039 if (res == 0 && (req->defobj_out == NULL || 4040 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4041 req->sym_out = req1.sym_out; 4042 req->defobj_out = req1.defobj_out; 4043 assert(req->defobj_out != NULL); 4044 } 4045 } 4046 4047 return (req->sym_out != NULL ? 0 : ESRCH); 4048 } 4049 4050 /* 4051 * Given a symbol name in a referencing object, find the corresponding 4052 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4053 * no definition was found. Returns a pointer to the Obj_Entry of the 4054 * defining object via the reference parameter DEFOBJ_OUT. 4055 */ 4056 static int 4057 symlook_default(SymLook *req, const Obj_Entry *refobj) 4058 { 4059 DoneList donelist; 4060 const Objlist_Entry *elm; 4061 SymLook req1; 4062 int res; 4063 4064 donelist_init(&donelist); 4065 symlook_init_from_req(&req1, req); 4066 4067 /* 4068 * Look first in the referencing object if linked symbolically, 4069 * and similarly handle protected symbols. 4070 */ 4071 res = symlook_obj(&req1, refobj); 4072 if (res == 0 && (refobj->symbolic || 4073 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4074 req->sym_out = req1.sym_out; 4075 req->defobj_out = req1.defobj_out; 4076 assert(req->defobj_out != NULL); 4077 } 4078 if (refobj->symbolic || req->defobj_out != NULL) 4079 donelist_check(&donelist, refobj); 4080 4081 symlook_global(req, &donelist); 4082 4083 /* Search all dlopened DAGs containing the referencing object. */ 4084 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4085 if (req->sym_out != NULL && 4086 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4087 break; 4088 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4089 if (res == 0 && (req->sym_out == NULL || 4090 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4091 req->sym_out = req1.sym_out; 4092 req->defobj_out = req1.defobj_out; 4093 assert(req->defobj_out != NULL); 4094 } 4095 } 4096 4097 /* 4098 * Search the dynamic linker itself, and possibly resolve the 4099 * symbol from there. This is how the application links to 4100 * dynamic linker services such as dlopen. 4101 */ 4102 if (req->sym_out == NULL || 4103 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4104 res = symlook_obj(&req1, &obj_rtld); 4105 if (res == 0) { 4106 req->sym_out = req1.sym_out; 4107 req->defobj_out = req1.defobj_out; 4108 assert(req->defobj_out != NULL); 4109 } 4110 } 4111 4112 return (req->sym_out != NULL ? 0 : ESRCH); 4113 } 4114 4115 static int 4116 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4117 { 4118 const Elf_Sym *def; 4119 const Obj_Entry *defobj; 4120 const Objlist_Entry *elm; 4121 SymLook req1; 4122 int res; 4123 4124 def = NULL; 4125 defobj = NULL; 4126 STAILQ_FOREACH(elm, objlist, link) { 4127 if (donelist_check(dlp, elm->obj)) 4128 continue; 4129 symlook_init_from_req(&req1, req); 4130 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4131 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4132 def = req1.sym_out; 4133 defobj = req1.defobj_out; 4134 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4135 break; 4136 } 4137 } 4138 } 4139 if (def != NULL) { 4140 req->sym_out = def; 4141 req->defobj_out = defobj; 4142 return (0); 4143 } 4144 return (ESRCH); 4145 } 4146 4147 /* 4148 * Search the chain of DAGS cointed to by the given Needed_Entry 4149 * for a symbol of the given name. Each DAG is scanned completely 4150 * before advancing to the next one. Returns a pointer to the symbol, 4151 * or NULL if no definition was found. 4152 */ 4153 static int 4154 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4155 { 4156 const Elf_Sym *def; 4157 const Needed_Entry *n; 4158 const Obj_Entry *defobj; 4159 SymLook req1; 4160 int res; 4161 4162 def = NULL; 4163 defobj = NULL; 4164 symlook_init_from_req(&req1, req); 4165 for (n = needed; n != NULL; n = n->next) { 4166 if (n->obj == NULL || 4167 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4168 continue; 4169 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4170 def = req1.sym_out; 4171 defobj = req1.defobj_out; 4172 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4173 break; 4174 } 4175 } 4176 if (def != NULL) { 4177 req->sym_out = def; 4178 req->defobj_out = defobj; 4179 return (0); 4180 } 4181 return (ESRCH); 4182 } 4183 4184 /* 4185 * Search the symbol table of a single shared object for a symbol of 4186 * the given name and version, if requested. Returns a pointer to the 4187 * symbol, or NULL if no definition was found. If the object is 4188 * filter, return filtered symbol from filtee. 4189 * 4190 * The symbol's hash value is passed in for efficiency reasons; that 4191 * eliminates many recomputations of the hash value. 4192 */ 4193 int 4194 symlook_obj(SymLook *req, const Obj_Entry *obj) 4195 { 4196 DoneList donelist; 4197 SymLook req1; 4198 int flags, res, mres; 4199 4200 /* 4201 * If there is at least one valid hash at this point, we prefer to 4202 * use the faster GNU version if available. 4203 */ 4204 if (obj->valid_hash_gnu) 4205 mres = symlook_obj1_gnu(req, obj); 4206 else if (obj->valid_hash_sysv) 4207 mres = symlook_obj1_sysv(req, obj); 4208 else 4209 return (EINVAL); 4210 4211 if (mres == 0) { 4212 if (obj->needed_filtees != NULL) { 4213 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4214 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4215 donelist_init(&donelist); 4216 symlook_init_from_req(&req1, req); 4217 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4218 if (res == 0) { 4219 req->sym_out = req1.sym_out; 4220 req->defobj_out = req1.defobj_out; 4221 } 4222 return (res); 4223 } 4224 if (obj->needed_aux_filtees != NULL) { 4225 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4226 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4227 donelist_init(&donelist); 4228 symlook_init_from_req(&req1, req); 4229 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4230 if (res == 0) { 4231 req->sym_out = req1.sym_out; 4232 req->defobj_out = req1.defobj_out; 4233 return (res); 4234 } 4235 } 4236 } 4237 return (mres); 4238 } 4239 4240 /* Symbol match routine common to both hash functions */ 4241 static bool 4242 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4243 const unsigned long symnum) 4244 { 4245 Elf_Versym verndx; 4246 const Elf_Sym *symp; 4247 const char *strp; 4248 4249 symp = obj->symtab + symnum; 4250 strp = obj->strtab + symp->st_name; 4251 4252 switch (ELF_ST_TYPE(symp->st_info)) { 4253 case STT_FUNC: 4254 case STT_NOTYPE: 4255 case STT_OBJECT: 4256 case STT_COMMON: 4257 case STT_GNU_IFUNC: 4258 if (symp->st_value == 0) 4259 return (false); 4260 /* fallthrough */ 4261 case STT_TLS: 4262 if (symp->st_shndx != SHN_UNDEF) 4263 break; 4264 #ifndef __mips__ 4265 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4266 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4267 break; 4268 /* fallthrough */ 4269 #endif 4270 default: 4271 return (false); 4272 } 4273 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4274 return (false); 4275 4276 if (req->ventry == NULL) { 4277 if (obj->versyms != NULL) { 4278 verndx = VER_NDX(obj->versyms[symnum]); 4279 if (verndx > obj->vernum) { 4280 _rtld_error( 4281 "%s: symbol %s references wrong version %d", 4282 obj->path, obj->strtab + symnum, verndx); 4283 return (false); 4284 } 4285 /* 4286 * If we are not called from dlsym (i.e. this 4287 * is a normal relocation from unversioned 4288 * binary), accept the symbol immediately if 4289 * it happens to have first version after this 4290 * shared object became versioned. Otherwise, 4291 * if symbol is versioned and not hidden, 4292 * remember it. If it is the only symbol with 4293 * this name exported by the shared object, it 4294 * will be returned as a match by the calling 4295 * function. If symbol is global (verndx < 2) 4296 * accept it unconditionally. 4297 */ 4298 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4299 verndx == VER_NDX_GIVEN) { 4300 result->sym_out = symp; 4301 return (true); 4302 } 4303 else if (verndx >= VER_NDX_GIVEN) { 4304 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4305 == 0) { 4306 if (result->vsymp == NULL) 4307 result->vsymp = symp; 4308 result->vcount++; 4309 } 4310 return (false); 4311 } 4312 } 4313 result->sym_out = symp; 4314 return (true); 4315 } 4316 if (obj->versyms == NULL) { 4317 if (object_match_name(obj, req->ventry->name)) { 4318 _rtld_error("%s: object %s should provide version %s " 4319 "for symbol %s", obj_rtld.path, obj->path, 4320 req->ventry->name, obj->strtab + symnum); 4321 return (false); 4322 } 4323 } else { 4324 verndx = VER_NDX(obj->versyms[symnum]); 4325 if (verndx > obj->vernum) { 4326 _rtld_error("%s: symbol %s references wrong version %d", 4327 obj->path, obj->strtab + symnum, verndx); 4328 return (false); 4329 } 4330 if (obj->vertab[verndx].hash != req->ventry->hash || 4331 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4332 /* 4333 * Version does not match. Look if this is a 4334 * global symbol and if it is not hidden. If 4335 * global symbol (verndx < 2) is available, 4336 * use it. Do not return symbol if we are 4337 * called by dlvsym, because dlvsym looks for 4338 * a specific version and default one is not 4339 * what dlvsym wants. 4340 */ 4341 if ((req->flags & SYMLOOK_DLSYM) || 4342 (verndx >= VER_NDX_GIVEN) || 4343 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4344 return (false); 4345 } 4346 } 4347 result->sym_out = symp; 4348 return (true); 4349 } 4350 4351 /* 4352 * Search for symbol using SysV hash function. 4353 * obj->buckets is known not to be NULL at this point; the test for this was 4354 * performed with the obj->valid_hash_sysv assignment. 4355 */ 4356 static int 4357 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4358 { 4359 unsigned long symnum; 4360 Sym_Match_Result matchres; 4361 4362 matchres.sym_out = NULL; 4363 matchres.vsymp = NULL; 4364 matchres.vcount = 0; 4365 4366 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4367 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4368 if (symnum >= obj->nchains) 4369 return (ESRCH); /* Bad object */ 4370 4371 if (matched_symbol(req, obj, &matchres, symnum)) { 4372 req->sym_out = matchres.sym_out; 4373 req->defobj_out = obj; 4374 return (0); 4375 } 4376 } 4377 if (matchres.vcount == 1) { 4378 req->sym_out = matchres.vsymp; 4379 req->defobj_out = obj; 4380 return (0); 4381 } 4382 return (ESRCH); 4383 } 4384 4385 /* Search for symbol using GNU hash function */ 4386 static int 4387 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4388 { 4389 Elf_Addr bloom_word; 4390 const Elf32_Word *hashval; 4391 Elf32_Word bucket; 4392 Sym_Match_Result matchres; 4393 unsigned int h1, h2; 4394 unsigned long symnum; 4395 4396 matchres.sym_out = NULL; 4397 matchres.vsymp = NULL; 4398 matchres.vcount = 0; 4399 4400 /* Pick right bitmask word from Bloom filter array */ 4401 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4402 obj->maskwords_bm_gnu]; 4403 4404 /* Calculate modulus word size of gnu hash and its derivative */ 4405 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4406 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4407 4408 /* Filter out the "definitely not in set" queries */ 4409 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4410 return (ESRCH); 4411 4412 /* Locate hash chain and corresponding value element*/ 4413 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4414 if (bucket == 0) 4415 return (ESRCH); 4416 hashval = &obj->chain_zero_gnu[bucket]; 4417 do { 4418 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4419 symnum = hashval - obj->chain_zero_gnu; 4420 if (matched_symbol(req, obj, &matchres, symnum)) { 4421 req->sym_out = matchres.sym_out; 4422 req->defobj_out = obj; 4423 return (0); 4424 } 4425 } 4426 } while ((*hashval++ & 1) == 0); 4427 if (matchres.vcount == 1) { 4428 req->sym_out = matchres.vsymp; 4429 req->defobj_out = obj; 4430 return (0); 4431 } 4432 return (ESRCH); 4433 } 4434 4435 static void 4436 trace_loaded_objects(Obj_Entry *obj) 4437 { 4438 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4439 int c; 4440 4441 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4442 main_local = ""; 4443 4444 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4445 fmt1 = "\t%o => %p (%x)\n"; 4446 4447 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4448 fmt2 = "\t%o (%x)\n"; 4449 4450 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4451 4452 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4453 Needed_Entry *needed; 4454 char *name, *path; 4455 bool is_lib; 4456 4457 if (obj->marker) 4458 continue; 4459 if (list_containers && obj->needed != NULL) 4460 rtld_printf("%s:\n", obj->path); 4461 for (needed = obj->needed; needed; needed = needed->next) { 4462 if (needed->obj != NULL) { 4463 if (needed->obj->traced && !list_containers) 4464 continue; 4465 needed->obj->traced = true; 4466 path = needed->obj->path; 4467 } else 4468 path = "not found"; 4469 4470 name = (char *)obj->strtab + needed->name; 4471 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4472 4473 fmt = is_lib ? fmt1 : fmt2; 4474 while ((c = *fmt++) != '\0') { 4475 switch (c) { 4476 default: 4477 rtld_putchar(c); 4478 continue; 4479 case '\\': 4480 switch (c = *fmt) { 4481 case '\0': 4482 continue; 4483 case 'n': 4484 rtld_putchar('\n'); 4485 break; 4486 case 't': 4487 rtld_putchar('\t'); 4488 break; 4489 } 4490 break; 4491 case '%': 4492 switch (c = *fmt) { 4493 case '\0': 4494 continue; 4495 case '%': 4496 default: 4497 rtld_putchar(c); 4498 break; 4499 case 'A': 4500 rtld_putstr(main_local); 4501 break; 4502 case 'a': 4503 rtld_putstr(obj_main->path); 4504 break; 4505 case 'o': 4506 rtld_putstr(name); 4507 break; 4508 #if 0 4509 case 'm': 4510 rtld_printf("%d", sodp->sod_major); 4511 break; 4512 case 'n': 4513 rtld_printf("%d", sodp->sod_minor); 4514 break; 4515 #endif 4516 case 'p': 4517 rtld_putstr(path); 4518 break; 4519 case 'x': 4520 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4521 0); 4522 break; 4523 } 4524 break; 4525 } 4526 ++fmt; 4527 } 4528 } 4529 } 4530 } 4531 4532 /* 4533 * Unload a dlopened object and its dependencies from memory and from 4534 * our data structures. It is assumed that the DAG rooted in the 4535 * object has already been unreferenced, and that the object has a 4536 * reference count of 0. 4537 */ 4538 static void 4539 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4540 { 4541 Obj_Entry marker, *obj, *next; 4542 4543 assert(root->refcount == 0); 4544 4545 /* 4546 * Pass over the DAG removing unreferenced objects from 4547 * appropriate lists. 4548 */ 4549 unlink_object(root); 4550 4551 /* Unmap all objects that are no longer referenced. */ 4552 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4553 next = TAILQ_NEXT(obj, next); 4554 if (obj->marker || obj->refcount != 0) 4555 continue; 4556 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4557 obj->mapsize, 0, obj->path); 4558 dbg("unloading \"%s\"", obj->path); 4559 /* 4560 * Unlink the object now to prevent new references from 4561 * being acquired while the bind lock is dropped in 4562 * recursive dlclose() invocations. 4563 */ 4564 TAILQ_REMOVE(&obj_list, obj, next); 4565 obj_count--; 4566 4567 if (obj->filtees_loaded) { 4568 if (next != NULL) { 4569 init_marker(&marker); 4570 TAILQ_INSERT_BEFORE(next, &marker, next); 4571 unload_filtees(obj, lockstate); 4572 next = TAILQ_NEXT(&marker, next); 4573 TAILQ_REMOVE(&obj_list, &marker, next); 4574 } else 4575 unload_filtees(obj, lockstate); 4576 } 4577 release_object(obj); 4578 } 4579 } 4580 4581 static void 4582 unlink_object(Obj_Entry *root) 4583 { 4584 Objlist_Entry *elm; 4585 4586 if (root->refcount == 0) { 4587 /* Remove the object from the RTLD_GLOBAL list. */ 4588 objlist_remove(&list_global, root); 4589 4590 /* Remove the object from all objects' DAG lists. */ 4591 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4592 objlist_remove(&elm->obj->dldags, root); 4593 if (elm->obj != root) 4594 unlink_object(elm->obj); 4595 } 4596 } 4597 } 4598 4599 static void 4600 ref_dag(Obj_Entry *root) 4601 { 4602 Objlist_Entry *elm; 4603 4604 assert(root->dag_inited); 4605 STAILQ_FOREACH(elm, &root->dagmembers, link) 4606 elm->obj->refcount++; 4607 } 4608 4609 static void 4610 unref_dag(Obj_Entry *root) 4611 { 4612 Objlist_Entry *elm; 4613 4614 assert(root->dag_inited); 4615 STAILQ_FOREACH(elm, &root->dagmembers, link) 4616 elm->obj->refcount--; 4617 } 4618 4619 /* 4620 * Common code for MD __tls_get_addr(). 4621 */ 4622 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4623 static void * 4624 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4625 { 4626 Elf_Addr *newdtv, *dtv; 4627 RtldLockState lockstate; 4628 int to_copy; 4629 4630 dtv = *dtvp; 4631 /* Check dtv generation in case new modules have arrived */ 4632 if (dtv[0] != tls_dtv_generation) { 4633 wlock_acquire(rtld_bind_lock, &lockstate); 4634 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4635 to_copy = dtv[1]; 4636 if (to_copy > tls_max_index) 4637 to_copy = tls_max_index; 4638 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4639 newdtv[0] = tls_dtv_generation; 4640 newdtv[1] = tls_max_index; 4641 free(dtv); 4642 lock_release(rtld_bind_lock, &lockstate); 4643 dtv = *dtvp = newdtv; 4644 } 4645 4646 /* Dynamically allocate module TLS if necessary */ 4647 if (dtv[index + 1] == 0) { 4648 /* Signal safe, wlock will block out signals. */ 4649 wlock_acquire(rtld_bind_lock, &lockstate); 4650 if (!dtv[index + 1]) 4651 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4652 lock_release(rtld_bind_lock, &lockstate); 4653 } 4654 return ((void *)(dtv[index + 1] + offset)); 4655 } 4656 4657 void * 4658 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4659 { 4660 Elf_Addr *dtv; 4661 4662 dtv = *dtvp; 4663 /* Check dtv generation in case new modules have arrived */ 4664 if (__predict_true(dtv[0] == tls_dtv_generation && 4665 dtv[index + 1] != 0)) 4666 return ((void *)(dtv[index + 1] + offset)); 4667 return (tls_get_addr_slow(dtvp, index, offset)); 4668 } 4669 4670 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4671 defined(__powerpc__) || defined(__riscv) 4672 4673 /* 4674 * Allocate Static TLS using the Variant I method. 4675 */ 4676 void * 4677 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4678 { 4679 Obj_Entry *obj; 4680 char *tcb; 4681 Elf_Addr **tls; 4682 Elf_Addr *dtv; 4683 Elf_Addr addr; 4684 int i; 4685 4686 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4687 return (oldtcb); 4688 4689 assert(tcbsize >= TLS_TCB_SIZE); 4690 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4691 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4692 4693 if (oldtcb != NULL) { 4694 memcpy(tls, oldtcb, tls_static_space); 4695 free(oldtcb); 4696 4697 /* Adjust the DTV. */ 4698 dtv = tls[0]; 4699 for (i = 0; i < dtv[1]; i++) { 4700 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4701 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4702 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4703 } 4704 } 4705 } else { 4706 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4707 tls[0] = dtv; 4708 dtv[0] = tls_dtv_generation; 4709 dtv[1] = tls_max_index; 4710 4711 for (obj = globallist_curr(objs); obj != NULL; 4712 obj = globallist_next(obj)) { 4713 if (obj->tlsoffset > 0) { 4714 addr = (Elf_Addr)tls + obj->tlsoffset; 4715 if (obj->tlsinitsize > 0) 4716 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4717 if (obj->tlssize > obj->tlsinitsize) 4718 memset((void*) (addr + obj->tlsinitsize), 0, 4719 obj->tlssize - obj->tlsinitsize); 4720 dtv[obj->tlsindex + 1] = addr; 4721 } 4722 } 4723 } 4724 4725 return (tcb); 4726 } 4727 4728 void 4729 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4730 { 4731 Elf_Addr *dtv; 4732 Elf_Addr tlsstart, tlsend; 4733 int dtvsize, i; 4734 4735 assert(tcbsize >= TLS_TCB_SIZE); 4736 4737 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4738 tlsend = tlsstart + tls_static_space; 4739 4740 dtv = *(Elf_Addr **)tlsstart; 4741 dtvsize = dtv[1]; 4742 for (i = 0; i < dtvsize; i++) { 4743 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4744 free((void*)dtv[i+2]); 4745 } 4746 } 4747 free(dtv); 4748 free(tcb); 4749 } 4750 4751 #endif 4752 4753 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4754 4755 /* 4756 * Allocate Static TLS using the Variant II method. 4757 */ 4758 void * 4759 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4760 { 4761 Obj_Entry *obj; 4762 size_t size, ralign; 4763 char *tls; 4764 Elf_Addr *dtv, *olddtv; 4765 Elf_Addr segbase, oldsegbase, addr; 4766 int i; 4767 4768 ralign = tcbalign; 4769 if (tls_static_max_align > ralign) 4770 ralign = tls_static_max_align; 4771 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4772 4773 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4774 tls = malloc_aligned(size, ralign); 4775 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4776 4777 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4778 ((Elf_Addr*)segbase)[0] = segbase; 4779 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4780 4781 dtv[0] = tls_dtv_generation; 4782 dtv[1] = tls_max_index; 4783 4784 if (oldtls) { 4785 /* 4786 * Copy the static TLS block over whole. 4787 */ 4788 oldsegbase = (Elf_Addr) oldtls; 4789 memcpy((void *)(segbase - tls_static_space), 4790 (const void *)(oldsegbase - tls_static_space), 4791 tls_static_space); 4792 4793 /* 4794 * If any dynamic TLS blocks have been created tls_get_addr(), 4795 * move them over. 4796 */ 4797 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4798 for (i = 0; i < olddtv[1]; i++) { 4799 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4800 dtv[i+2] = olddtv[i+2]; 4801 olddtv[i+2] = 0; 4802 } 4803 } 4804 4805 /* 4806 * We assume that this block was the one we created with 4807 * allocate_initial_tls(). 4808 */ 4809 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4810 } else { 4811 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4812 if (obj->marker || obj->tlsoffset == 0) 4813 continue; 4814 addr = segbase - obj->tlsoffset; 4815 memset((void*) (addr + obj->tlsinitsize), 4816 0, obj->tlssize - obj->tlsinitsize); 4817 if (obj->tlsinit) 4818 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4819 dtv[obj->tlsindex + 1] = addr; 4820 } 4821 } 4822 4823 return (void*) segbase; 4824 } 4825 4826 void 4827 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4828 { 4829 Elf_Addr* dtv; 4830 size_t size, ralign; 4831 int dtvsize, i; 4832 Elf_Addr tlsstart, tlsend; 4833 4834 /* 4835 * Figure out the size of the initial TLS block so that we can 4836 * find stuff which ___tls_get_addr() allocated dynamically. 4837 */ 4838 ralign = tcbalign; 4839 if (tls_static_max_align > ralign) 4840 ralign = tls_static_max_align; 4841 size = round(tls_static_space, ralign); 4842 4843 dtv = ((Elf_Addr**)tls)[1]; 4844 dtvsize = dtv[1]; 4845 tlsend = (Elf_Addr) tls; 4846 tlsstart = tlsend - size; 4847 for (i = 0; i < dtvsize; i++) { 4848 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4849 free_aligned((void *)dtv[i + 2]); 4850 } 4851 } 4852 4853 free_aligned((void *)tlsstart); 4854 free((void*) dtv); 4855 } 4856 4857 #endif 4858 4859 /* 4860 * Allocate TLS block for module with given index. 4861 */ 4862 void * 4863 allocate_module_tls(int index) 4864 { 4865 Obj_Entry* obj; 4866 char* p; 4867 4868 TAILQ_FOREACH(obj, &obj_list, next) { 4869 if (obj->marker) 4870 continue; 4871 if (obj->tlsindex == index) 4872 break; 4873 } 4874 if (!obj) { 4875 _rtld_error("Can't find module with TLS index %d", index); 4876 rtld_die(); 4877 } 4878 4879 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4880 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4881 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4882 4883 return p; 4884 } 4885 4886 bool 4887 allocate_tls_offset(Obj_Entry *obj) 4888 { 4889 size_t off; 4890 4891 if (obj->tls_done) 4892 return true; 4893 4894 if (obj->tlssize == 0) { 4895 obj->tls_done = true; 4896 return true; 4897 } 4898 4899 if (tls_last_offset == 0) 4900 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4901 else 4902 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4903 obj->tlssize, obj->tlsalign); 4904 4905 /* 4906 * If we have already fixed the size of the static TLS block, we 4907 * must stay within that size. When allocating the static TLS, we 4908 * leave a small amount of space spare to be used for dynamically 4909 * loading modules which use static TLS. 4910 */ 4911 if (tls_static_space != 0) { 4912 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4913 return false; 4914 } else if (obj->tlsalign > tls_static_max_align) { 4915 tls_static_max_align = obj->tlsalign; 4916 } 4917 4918 tls_last_offset = obj->tlsoffset = off; 4919 tls_last_size = obj->tlssize; 4920 obj->tls_done = true; 4921 4922 return true; 4923 } 4924 4925 void 4926 free_tls_offset(Obj_Entry *obj) 4927 { 4928 4929 /* 4930 * If we were the last thing to allocate out of the static TLS 4931 * block, we give our space back to the 'allocator'. This is a 4932 * simplistic workaround to allow libGL.so.1 to be loaded and 4933 * unloaded multiple times. 4934 */ 4935 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4936 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4937 tls_last_offset -= obj->tlssize; 4938 tls_last_size = 0; 4939 } 4940 } 4941 4942 void * 4943 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4944 { 4945 void *ret; 4946 RtldLockState lockstate; 4947 4948 wlock_acquire(rtld_bind_lock, &lockstate); 4949 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4950 tcbsize, tcbalign); 4951 lock_release(rtld_bind_lock, &lockstate); 4952 return (ret); 4953 } 4954 4955 void 4956 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4957 { 4958 RtldLockState lockstate; 4959 4960 wlock_acquire(rtld_bind_lock, &lockstate); 4961 free_tls(tcb, tcbsize, tcbalign); 4962 lock_release(rtld_bind_lock, &lockstate); 4963 } 4964 4965 static void 4966 object_add_name(Obj_Entry *obj, const char *name) 4967 { 4968 Name_Entry *entry; 4969 size_t len; 4970 4971 len = strlen(name); 4972 entry = malloc(sizeof(Name_Entry) + len); 4973 4974 if (entry != NULL) { 4975 strcpy(entry->name, name); 4976 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4977 } 4978 } 4979 4980 static int 4981 object_match_name(const Obj_Entry *obj, const char *name) 4982 { 4983 Name_Entry *entry; 4984 4985 STAILQ_FOREACH(entry, &obj->names, link) { 4986 if (strcmp(name, entry->name) == 0) 4987 return (1); 4988 } 4989 return (0); 4990 } 4991 4992 static Obj_Entry * 4993 locate_dependency(const Obj_Entry *obj, const char *name) 4994 { 4995 const Objlist_Entry *entry; 4996 const Needed_Entry *needed; 4997 4998 STAILQ_FOREACH(entry, &list_main, link) { 4999 if (object_match_name(entry->obj, name)) 5000 return entry->obj; 5001 } 5002 5003 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5004 if (strcmp(obj->strtab + needed->name, name) == 0 || 5005 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5006 /* 5007 * If there is DT_NEEDED for the name we are looking for, 5008 * we are all set. Note that object might not be found if 5009 * dependency was not loaded yet, so the function can 5010 * return NULL here. This is expected and handled 5011 * properly by the caller. 5012 */ 5013 return (needed->obj); 5014 } 5015 } 5016 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5017 obj->path, name); 5018 rtld_die(); 5019 } 5020 5021 static int 5022 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5023 const Elf_Vernaux *vna) 5024 { 5025 const Elf_Verdef *vd; 5026 const char *vername; 5027 5028 vername = refobj->strtab + vna->vna_name; 5029 vd = depobj->verdef; 5030 if (vd == NULL) { 5031 _rtld_error("%s: version %s required by %s not defined", 5032 depobj->path, vername, refobj->path); 5033 return (-1); 5034 } 5035 for (;;) { 5036 if (vd->vd_version != VER_DEF_CURRENT) { 5037 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5038 depobj->path, vd->vd_version); 5039 return (-1); 5040 } 5041 if (vna->vna_hash == vd->vd_hash) { 5042 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5043 ((char *)vd + vd->vd_aux); 5044 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5045 return (0); 5046 } 5047 if (vd->vd_next == 0) 5048 break; 5049 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5050 } 5051 if (vna->vna_flags & VER_FLG_WEAK) 5052 return (0); 5053 _rtld_error("%s: version %s required by %s not found", 5054 depobj->path, vername, refobj->path); 5055 return (-1); 5056 } 5057 5058 static int 5059 rtld_verify_object_versions(Obj_Entry *obj) 5060 { 5061 const Elf_Verneed *vn; 5062 const Elf_Verdef *vd; 5063 const Elf_Verdaux *vda; 5064 const Elf_Vernaux *vna; 5065 const Obj_Entry *depobj; 5066 int maxvernum, vernum; 5067 5068 if (obj->ver_checked) 5069 return (0); 5070 obj->ver_checked = true; 5071 5072 maxvernum = 0; 5073 /* 5074 * Walk over defined and required version records and figure out 5075 * max index used by any of them. Do very basic sanity checking 5076 * while there. 5077 */ 5078 vn = obj->verneed; 5079 while (vn != NULL) { 5080 if (vn->vn_version != VER_NEED_CURRENT) { 5081 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5082 obj->path, vn->vn_version); 5083 return (-1); 5084 } 5085 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5086 for (;;) { 5087 vernum = VER_NEED_IDX(vna->vna_other); 5088 if (vernum > maxvernum) 5089 maxvernum = vernum; 5090 if (vna->vna_next == 0) 5091 break; 5092 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5093 } 5094 if (vn->vn_next == 0) 5095 break; 5096 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5097 } 5098 5099 vd = obj->verdef; 5100 while (vd != NULL) { 5101 if (vd->vd_version != VER_DEF_CURRENT) { 5102 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5103 obj->path, vd->vd_version); 5104 return (-1); 5105 } 5106 vernum = VER_DEF_IDX(vd->vd_ndx); 5107 if (vernum > maxvernum) 5108 maxvernum = vernum; 5109 if (vd->vd_next == 0) 5110 break; 5111 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5112 } 5113 5114 if (maxvernum == 0) 5115 return (0); 5116 5117 /* 5118 * Store version information in array indexable by version index. 5119 * Verify that object version requirements are satisfied along the 5120 * way. 5121 */ 5122 obj->vernum = maxvernum + 1; 5123 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5124 5125 vd = obj->verdef; 5126 while (vd != NULL) { 5127 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5128 vernum = VER_DEF_IDX(vd->vd_ndx); 5129 assert(vernum <= maxvernum); 5130 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5131 obj->vertab[vernum].hash = vd->vd_hash; 5132 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5133 obj->vertab[vernum].file = NULL; 5134 obj->vertab[vernum].flags = 0; 5135 } 5136 if (vd->vd_next == 0) 5137 break; 5138 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5139 } 5140 5141 vn = obj->verneed; 5142 while (vn != NULL) { 5143 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5144 if (depobj == NULL) 5145 return (-1); 5146 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5147 for (;;) { 5148 if (check_object_provided_version(obj, depobj, vna)) 5149 return (-1); 5150 vernum = VER_NEED_IDX(vna->vna_other); 5151 assert(vernum <= maxvernum); 5152 obj->vertab[vernum].hash = vna->vna_hash; 5153 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5154 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5155 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5156 VER_INFO_HIDDEN : 0; 5157 if (vna->vna_next == 0) 5158 break; 5159 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5160 } 5161 if (vn->vn_next == 0) 5162 break; 5163 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5164 } 5165 return 0; 5166 } 5167 5168 static int 5169 rtld_verify_versions(const Objlist *objlist) 5170 { 5171 Objlist_Entry *entry; 5172 int rc; 5173 5174 rc = 0; 5175 STAILQ_FOREACH(entry, objlist, link) { 5176 /* 5177 * Skip dummy objects or objects that have their version requirements 5178 * already checked. 5179 */ 5180 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5181 continue; 5182 if (rtld_verify_object_versions(entry->obj) == -1) { 5183 rc = -1; 5184 if (ld_tracing == NULL) 5185 break; 5186 } 5187 } 5188 if (rc == 0 || ld_tracing != NULL) 5189 rc = rtld_verify_object_versions(&obj_rtld); 5190 return rc; 5191 } 5192 5193 const Ver_Entry * 5194 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5195 { 5196 Elf_Versym vernum; 5197 5198 if (obj->vertab) { 5199 vernum = VER_NDX(obj->versyms[symnum]); 5200 if (vernum >= obj->vernum) { 5201 _rtld_error("%s: symbol %s has wrong verneed value %d", 5202 obj->path, obj->strtab + symnum, vernum); 5203 } else if (obj->vertab[vernum].hash != 0) { 5204 return &obj->vertab[vernum]; 5205 } 5206 } 5207 return NULL; 5208 } 5209 5210 int 5211 _rtld_get_stack_prot(void) 5212 { 5213 5214 return (stack_prot); 5215 } 5216 5217 int 5218 _rtld_is_dlopened(void *arg) 5219 { 5220 Obj_Entry *obj; 5221 RtldLockState lockstate; 5222 int res; 5223 5224 rlock_acquire(rtld_bind_lock, &lockstate); 5225 obj = dlcheck(arg); 5226 if (obj == NULL) 5227 obj = obj_from_addr(arg); 5228 if (obj == NULL) { 5229 _rtld_error("No shared object contains address"); 5230 lock_release(rtld_bind_lock, &lockstate); 5231 return (-1); 5232 } 5233 res = obj->dlopened ? 1 : 0; 5234 lock_release(rtld_bind_lock, &lockstate); 5235 return (res); 5236 } 5237 5238 int 5239 obj_enforce_relro(Obj_Entry *obj) 5240 { 5241 5242 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5243 PROT_READ) == -1) { 5244 _rtld_error("%s: Cannot enforce relro protection: %s", 5245 obj->path, rtld_strerror(errno)); 5246 return (-1); 5247 } 5248 return (0); 5249 } 5250 5251 static void 5252 map_stacks_exec(RtldLockState *lockstate) 5253 { 5254 void (*thr_map_stacks_exec)(void); 5255 5256 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5257 return; 5258 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5259 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5260 if (thr_map_stacks_exec != NULL) { 5261 stack_prot |= PROT_EXEC; 5262 thr_map_stacks_exec(); 5263 } 5264 } 5265 5266 void 5267 symlook_init(SymLook *dst, const char *name) 5268 { 5269 5270 bzero(dst, sizeof(*dst)); 5271 dst->name = name; 5272 dst->hash = elf_hash(name); 5273 dst->hash_gnu = gnu_hash(name); 5274 } 5275 5276 static void 5277 symlook_init_from_req(SymLook *dst, const SymLook *src) 5278 { 5279 5280 dst->name = src->name; 5281 dst->hash = src->hash; 5282 dst->hash_gnu = src->hash_gnu; 5283 dst->ventry = src->ventry; 5284 dst->flags = src->flags; 5285 dst->defobj_out = NULL; 5286 dst->sym_out = NULL; 5287 dst->lockstate = src->lockstate; 5288 } 5289 5290 static int 5291 open_binary_fd(const char *argv0, bool search_in_path) 5292 { 5293 char *pathenv, *pe, binpath[PATH_MAX]; 5294 int fd; 5295 5296 if (search_in_path && strchr(argv0, '/') == NULL) { 5297 pathenv = getenv("PATH"); 5298 if (pathenv == NULL) { 5299 rtld_printf("-p and no PATH environment variable\n"); 5300 rtld_die(); 5301 } 5302 pathenv = strdup(pathenv); 5303 if (pathenv == NULL) { 5304 rtld_printf("Cannot allocate memory\n"); 5305 rtld_die(); 5306 } 5307 fd = -1; 5308 errno = ENOENT; 5309 while ((pe = strsep(&pathenv, ":")) != NULL) { 5310 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5311 sizeof(binpath)) 5312 continue; 5313 if (binpath[0] != '\0' && 5314 strlcat(binpath, "/", sizeof(binpath)) >= 5315 sizeof(binpath)) 5316 continue; 5317 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5318 sizeof(binpath)) 5319 continue; 5320 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5321 if (fd != -1 || errno != ENOENT) 5322 break; 5323 } 5324 free(pathenv); 5325 } else { 5326 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5327 } 5328 5329 if (fd == -1) { 5330 rtld_printf("Opening %s: %s\n", argv0, 5331 rtld_strerror(errno)); 5332 rtld_die(); 5333 } 5334 return (fd); 5335 } 5336 5337 /* 5338 * Parse a set of command-line arguments. 5339 */ 5340 static int 5341 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5342 { 5343 const char *arg; 5344 int fd, i, j, arglen; 5345 char opt; 5346 5347 dbg("Parsing command-line arguments"); 5348 *use_pathp = false; 5349 *fdp = -1; 5350 5351 for (i = 1; i < argc; i++ ) { 5352 arg = argv[i]; 5353 dbg("argv[%d]: '%s'", i, arg); 5354 5355 /* 5356 * rtld arguments end with an explicit "--" or with the first 5357 * non-prefixed argument. 5358 */ 5359 if (strcmp(arg, "--") == 0) { 5360 i++; 5361 break; 5362 } 5363 if (arg[0] != '-') 5364 break; 5365 5366 /* 5367 * All other arguments are single-character options that can 5368 * be combined, so we need to search through `arg` for them. 5369 */ 5370 arglen = strlen(arg); 5371 for (j = 1; j < arglen; j++) { 5372 opt = arg[j]; 5373 if (opt == 'h') { 5374 print_usage(argv[0]); 5375 rtld_die(); 5376 } else if (opt == 'f') { 5377 /* 5378 * -f XX can be used to specify a descriptor for the 5379 * binary named at the command line (i.e., the later 5380 * argument will specify the process name but the 5381 * descriptor is what will actually be executed) 5382 */ 5383 if (j != arglen - 1) { 5384 /* -f must be the last option in, e.g., -abcf */ 5385 _rtld_error("invalid options: %s", arg); 5386 rtld_die(); 5387 } 5388 i++; 5389 fd = parse_integer(argv[i]); 5390 if (fd == -1) { 5391 _rtld_error("invalid file descriptor: '%s'", 5392 argv[i]); 5393 rtld_die(); 5394 } 5395 *fdp = fd; 5396 break; 5397 } else if (opt == 'p') { 5398 *use_pathp = true; 5399 } else { 5400 rtld_printf("invalid argument: '%s'\n", arg); 5401 print_usage(argv[0]); 5402 rtld_die(); 5403 } 5404 } 5405 } 5406 5407 return (i); 5408 } 5409 5410 /* 5411 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5412 */ 5413 static int 5414 parse_integer(const char *str) 5415 { 5416 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5417 const char *orig; 5418 int n; 5419 char c; 5420 5421 orig = str; 5422 n = 0; 5423 for (c = *str; c != '\0'; c = *++str) { 5424 if (c < '0' || c > '9') 5425 return (-1); 5426 5427 n *= RADIX; 5428 n += c - '0'; 5429 } 5430 5431 /* Make sure we actually parsed something. */ 5432 if (str == orig) 5433 return (-1); 5434 return (n); 5435 } 5436 5437 static void 5438 print_usage(const char *argv0) 5439 { 5440 5441 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5442 "\n" 5443 "Options:\n" 5444 " -h Display this help message\n" 5445 " -p Search in PATH for named binary\n" 5446 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5447 " -- End of RTLD options\n" 5448 " <binary> Name of process to execute\n" 5449 " <args> Arguments to the executed process\n", argv0); 5450 } 5451 5452 /* 5453 * Overrides for libc_pic-provided functions. 5454 */ 5455 5456 int 5457 __getosreldate(void) 5458 { 5459 size_t len; 5460 int oid[2]; 5461 int error, osrel; 5462 5463 if (osreldate != 0) 5464 return (osreldate); 5465 5466 oid[0] = CTL_KERN; 5467 oid[1] = KERN_OSRELDATE; 5468 osrel = 0; 5469 len = sizeof(osrel); 5470 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5471 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5472 osreldate = osrel; 5473 return (osreldate); 5474 } 5475 5476 void 5477 exit(int status) 5478 { 5479 5480 _exit(status); 5481 } 5482 5483 void (*__cleanup)(void); 5484 int __isthreaded = 0; 5485 int _thread_autoinit_dummy_decl = 1; 5486 5487 /* 5488 * No unresolved symbols for rtld. 5489 */ 5490 void 5491 __pthread_cxa_finalize(struct dl_phdr_info *a) 5492 { 5493 } 5494 5495 void 5496 __stack_chk_fail(void) 5497 { 5498 5499 _rtld_error("stack overflow detected; terminated"); 5500 rtld_die(); 5501 } 5502 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5503 5504 void 5505 __chk_fail(void) 5506 { 5507 5508 _rtld_error("buffer overflow detected; terminated"); 5509 rtld_die(); 5510 } 5511 5512 const char * 5513 rtld_strerror(int errnum) 5514 { 5515 5516 if (errnum < 0 || errnum >= sys_nerr) 5517 return ("Unknown error"); 5518 return (sys_errlist[errnum]); 5519 } 5520