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