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