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 <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 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 <[email protected]>. 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, const char *, 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_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 138 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 139 int flags, RtldLockState *lockstate); 140 static int rtld_dirname(const char *, char *); 141 static int rtld_dirname_abs(const char *, char *); 142 static void *rtld_dlopen(const char *name, int fd, int mode); 143 static void rtld_exit(void); 144 static char *search_library_path(const char *, const char *, const char *, 145 int *); 146 static char *search_library_pathfds(const char *, const char *, int *); 147 static const void **get_program_var_addr(const char *, RtldLockState *); 148 static void set_program_var(const char *, const void *); 149 static int symlook_default(SymLook *, const Obj_Entry *refobj); 150 static int symlook_global(SymLook *, DoneList *); 151 static void symlook_init_from_req(SymLook *, const SymLook *); 152 static int symlook_list(SymLook *, const Objlist *, DoneList *); 153 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 154 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 155 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 156 static void trace_loaded_objects(Obj_Entry *); 157 static void unlink_object(Obj_Entry *); 158 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 159 static void unref_dag(Obj_Entry *); 160 static void ref_dag(Obj_Entry *); 161 static char *origin_subst_one(Obj_Entry *, char *, const char *, 162 const char *, bool); 163 static char *origin_subst(Obj_Entry *, char *); 164 static bool obj_resolve_origin(Obj_Entry *obj); 165 static void preinit_main(void); 166 static int rtld_verify_versions(const Objlist *); 167 static int rtld_verify_object_versions(Obj_Entry *); 168 static void object_add_name(Obj_Entry *, const char *); 169 static int object_match_name(const Obj_Entry *, const char *); 170 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 171 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 172 struct dl_phdr_info *phdr_info); 173 static uint32_t gnu_hash(const char *); 174 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 175 const unsigned long); 176 177 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 178 void _r_debug_postinit(struct link_map *) __noinline __exported; 179 180 int __sys_openat(int, const char *, int, ...); 181 182 /* 183 * Data declarations. 184 */ 185 static char *error_message; /* Message for dlerror(), or NULL */ 186 struct r_debug r_debug __exported; /* for GDB; */ 187 static bool libmap_disable; /* Disable libmap */ 188 static bool ld_loadfltr; /* Immediate filters processing */ 189 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 190 static bool trust; /* False for setuid and setgid programs */ 191 static bool dangerous_ld_env; /* True if environment variables have been 192 used to affect the libraries loaded */ 193 bool ld_bind_not; /* Disable PLT update */ 194 static char *ld_bind_now; /* Environment variable for immediate binding */ 195 static char *ld_debug; /* Environment variable for debugging */ 196 static char *ld_library_path; /* Environment variable for search path */ 197 static char *ld_library_dirs; /* Environment variable for library descriptors */ 198 static char *ld_preload; /* Environment variable for libraries to 199 load first */ 200 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 201 static char *ld_tracing; /* Called from ldd to print libs */ 202 static char *ld_utrace; /* Use utrace() to log events. */ 203 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 204 static Obj_Entry *obj_main; /* The main program shared object */ 205 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 206 static unsigned int obj_count; /* Number of objects in obj_list */ 207 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 208 209 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 210 STAILQ_HEAD_INITIALIZER(list_global); 211 static Objlist list_main = /* Objects loaded at program startup */ 212 STAILQ_HEAD_INITIALIZER(list_main); 213 static Objlist list_fini = /* Objects needing fini() calls */ 214 STAILQ_HEAD_INITIALIZER(list_fini); 215 216 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 217 218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 219 220 extern Elf_Dyn _DYNAMIC; 221 #pragma weak _DYNAMIC 222 223 int dlclose(void *) __exported; 224 char *dlerror(void) __exported; 225 void *dlopen(const char *, int) __exported; 226 void *fdlopen(int, int) __exported; 227 void *dlsym(void *, const char *) __exported; 228 dlfunc_t dlfunc(void *, const char *) __exported; 229 void *dlvsym(void *, const char *, const char *) __exported; 230 int dladdr(const void *, Dl_info *) __exported; 231 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 232 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 233 int dlinfo(void *, int , void *) __exported; 234 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 235 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 236 int _rtld_get_stack_prot(void) __exported; 237 int _rtld_is_dlopened(void *) __exported; 238 void _rtld_error(const char *, ...) __exported; 239 240 int npagesizes, osreldate; 241 size_t *pagesizes; 242 243 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 244 static int max_stack_flags; 245 246 /* 247 * Global declarations normally provided by crt1. The dynamic linker is 248 * not built with crt1, so we have to provide them ourselves. 249 */ 250 char *__progname; 251 char **environ; 252 253 /* 254 * Used to pass argc, argv to init functions. 255 */ 256 int main_argc; 257 char **main_argv; 258 259 /* 260 * Globals to control TLS allocation. 261 */ 262 size_t tls_last_offset; /* Static TLS offset of last module */ 263 size_t tls_last_size; /* Static TLS size of last module */ 264 size_t tls_static_space; /* Static TLS space allocated */ 265 size_t tls_static_max_align; 266 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 267 int tls_max_index = 1; /* Largest module index allocated */ 268 269 bool ld_library_path_rpath = false; 270 271 /* 272 * Globals for path names, and such 273 */ 274 char *ld_elf_hints_default = _PATH_ELF_HINTS; 275 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 276 char *ld_path_rtld = _PATH_RTLD; 277 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 278 char *ld_env_prefix = LD_; 279 280 /* 281 * Fill in a DoneList with an allocation large enough to hold all of 282 * the currently-loaded objects. Keep this as a macro since it calls 283 * alloca and we want that to occur within the scope of the caller. 284 */ 285 #define donelist_init(dlp) \ 286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 287 assert((dlp)->objs != NULL), \ 288 (dlp)->num_alloc = obj_count, \ 289 (dlp)->num_used = 0) 290 291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294 } while (0) 295 296 static void 297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299 { 300 struct utrace_rtld ut; 301 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 302 303 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 #ifdef RTLD_VARIANT_ENV_NAMES 316 /* 317 * construct the env variable based on the type of binary that's 318 * running. 319 */ 320 static inline const char * 321 _LD(const char *var) 322 { 323 static char buffer[128]; 324 325 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 326 strlcat(buffer, var, sizeof(buffer)); 327 return (buffer); 328 } 329 #else 330 #define _LD(x) LD_ x 331 #endif 332 333 /* 334 * Main entry point for dynamic linking. The first argument is the 335 * stack pointer. The stack is expected to be laid out as described 336 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 337 * Specifically, the stack pointer points to a word containing 338 * ARGC. Following that in the stack is a null-terminated sequence 339 * of pointers to argument strings. Then comes a null-terminated 340 * sequence of pointers to environment strings. Finally, there is a 341 * sequence of "auxiliary vector" entries. 342 * 343 * The second argument points to a place to store the dynamic linker's 344 * exit procedure pointer and the third to a place to store the main 345 * program's object. 346 * 347 * The return value is the main program's entry point. 348 */ 349 func_ptr_type 350 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 351 { 352 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 353 Objlist_Entry *entry; 354 Obj_Entry *last_interposer, *obj, *preload_tail; 355 const Elf_Phdr *phdr; 356 Objlist initlist; 357 RtldLockState lockstate; 358 struct stat st; 359 Elf_Addr *argcp; 360 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 361 caddr_t imgentry; 362 char buf[MAXPATHLEN]; 363 int argc, fd, i, phnum, rtld_argc; 364 bool dir_enable, explicit_fd, search_in_path; 365 366 /* 367 * On entry, the dynamic linker itself has not been relocated yet. 368 * Be very careful not to reference any global data until after 369 * init_rtld has returned. It is OK to reference file-scope statics 370 * and string constants, and to call static and global functions. 371 */ 372 373 /* Find the auxiliary vector on the stack. */ 374 argcp = sp; 375 argc = *sp++; 376 argv = (char **) sp; 377 sp += argc + 1; /* Skip over arguments and NULL terminator */ 378 env = (char **) sp; 379 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 380 ; 381 aux = (Elf_Auxinfo *) sp; 382 383 /* Digest the auxiliary vector. */ 384 for (i = 0; i < AT_COUNT; i++) 385 aux_info[i] = NULL; 386 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 387 if (auxp->a_type < AT_COUNT) 388 aux_info[auxp->a_type] = auxp; 389 } 390 391 /* Initialize and relocate ourselves. */ 392 assert(aux_info[AT_BASE] != NULL); 393 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 394 395 __progname = obj_rtld.path; 396 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 397 environ = env; 398 main_argc = argc; 399 main_argv = argv; 400 401 trust = !issetugid(); 402 403 md_abi_variant_hook(aux_info); 404 405 fd = -1; 406 if (aux_info[AT_EXECFD] != NULL) { 407 fd = aux_info[AT_EXECFD]->a_un.a_val; 408 } else { 409 assert(aux_info[AT_PHDR] != NULL); 410 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 411 if (phdr == obj_rtld.phdr) { 412 if (!trust) { 413 _rtld_error("Tainted process refusing to run binary %s", 414 argv0); 415 rtld_die(); 416 } 417 dbg("opening main program in direct exec mode"); 418 if (argc >= 2) { 419 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 420 argv0 = argv[rtld_argc]; 421 explicit_fd = (fd != -1); 422 if (!explicit_fd) 423 fd = open_binary_fd(argv0, search_in_path); 424 if (fstat(fd, &st) == -1) { 425 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 426 explicit_fd ? "user-provided descriptor" : argv0, 427 rtld_strerror(errno)); 428 rtld_die(); 429 } 430 431 /* 432 * Rough emulation of the permission checks done by 433 * execve(2), only Unix DACs are checked, ACLs are 434 * ignored. Preserve the semantic of disabling owner 435 * to execute if owner x bit is cleared, even if 436 * others x bit is enabled. 437 * mmap(2) does not allow to mmap with PROT_EXEC if 438 * binary' file comes from noexec mount. We cannot 439 * set VV_TEXT on the binary. 440 */ 441 dir_enable = false; 442 if (st.st_uid == geteuid()) { 443 if ((st.st_mode & S_IXUSR) != 0) 444 dir_enable = true; 445 } else if (st.st_gid == getegid()) { 446 if ((st.st_mode & S_IXGRP) != 0) 447 dir_enable = true; 448 } else if ((st.st_mode & S_IXOTH) != 0) { 449 dir_enable = true; 450 } 451 if (!dir_enable) { 452 _rtld_error("No execute permission for binary %s", 453 argv0); 454 rtld_die(); 455 } 456 457 /* 458 * For direct exec mode, argv[0] is the interpreter 459 * name, we must remove it and shift arguments left 460 * before invoking binary main. Since stack layout 461 * places environment pointers and aux vectors right 462 * after the terminating NULL, we must shift 463 * environment and aux as well. 464 */ 465 main_argc = argc - rtld_argc; 466 for (i = 0; i <= main_argc; i++) 467 argv[i] = argv[i + rtld_argc]; 468 *argcp -= rtld_argc; 469 environ = env = envp = argv + main_argc + 1; 470 do { 471 *envp = *(envp + rtld_argc); 472 envp++; 473 } while (*envp != NULL); 474 aux = auxp = (Elf_Auxinfo *)envp; 475 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 476 for (;; auxp++, auxpf++) { 477 *auxp = *auxpf; 478 if (auxp->a_type == AT_NULL) 479 break; 480 } 481 } else { 482 _rtld_error("No binary"); 483 rtld_die(); 484 } 485 } 486 } 487 488 ld_bind_now = getenv(_LD("BIND_NOW")); 489 490 /* 491 * If the process is tainted, then we un-set the dangerous environment 492 * variables. The process will be marked as tainted until setuid(2) 493 * is called. If any child process calls setuid(2) we do not want any 494 * future processes to honor the potentially un-safe variables. 495 */ 496 if (!trust) { 497 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 498 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 499 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 500 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 501 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 502 _rtld_error("environment corrupt; aborting"); 503 rtld_die(); 504 } 505 } 506 ld_debug = getenv(_LD("DEBUG")); 507 if (ld_bind_now == NULL) 508 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 509 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 510 libmap_override = getenv(_LD("LIBMAP")); 511 ld_library_path = getenv(_LD("LIBRARY_PATH")); 512 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 513 ld_preload = getenv(_LD("PRELOAD")); 514 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 515 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 516 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 517 if (library_path_rpath != NULL) { 518 if (library_path_rpath[0] == 'y' || 519 library_path_rpath[0] == 'Y' || 520 library_path_rpath[0] == '1') 521 ld_library_path_rpath = true; 522 else 523 ld_library_path_rpath = false; 524 } 525 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 526 (ld_library_path != NULL) || (ld_preload != NULL) || 527 (ld_elf_hints_path != NULL) || ld_loadfltr; 528 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 529 ld_utrace = getenv(_LD("UTRACE")); 530 531 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 532 ld_elf_hints_path = ld_elf_hints_default; 533 534 if (ld_debug != NULL && *ld_debug != '\0') 535 debug = 1; 536 dbg("%s is initialized, base address = %p", __progname, 537 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 538 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 539 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 540 541 dbg("initializing thread locks"); 542 lockdflt_init(); 543 544 /* 545 * Load the main program, or process its program header if it is 546 * already loaded. 547 */ 548 if (fd != -1) { /* Load the main program. */ 549 dbg("loading main program"); 550 obj_main = map_object(fd, argv0, NULL); 551 close(fd); 552 if (obj_main == NULL) 553 rtld_die(); 554 max_stack_flags = obj_main->stack_flags; 555 } else { /* Main program already loaded. */ 556 dbg("processing main program's program header"); 557 assert(aux_info[AT_PHDR] != NULL); 558 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 559 assert(aux_info[AT_PHNUM] != NULL); 560 phnum = aux_info[AT_PHNUM]->a_un.a_val; 561 assert(aux_info[AT_PHENT] != NULL); 562 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 563 assert(aux_info[AT_ENTRY] != NULL); 564 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 565 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 566 rtld_die(); 567 } 568 569 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 570 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 571 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 572 if (kexecpath[0] == '/') 573 obj_main->path = kexecpath; 574 else if (getcwd(buf, sizeof(buf)) == NULL || 575 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 576 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 577 obj_main->path = xstrdup(argv0); 578 else 579 obj_main->path = xstrdup(buf); 580 } else { 581 dbg("No AT_EXECPATH or direct exec"); 582 obj_main->path = xstrdup(argv0); 583 } 584 dbg("obj_main path %s", obj_main->path); 585 obj_main->mainprog = true; 586 587 if (aux_info[AT_STACKPROT] != NULL && 588 aux_info[AT_STACKPROT]->a_un.a_val != 0) 589 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 590 591 #ifndef COMPAT_32BIT 592 /* 593 * Get the actual dynamic linker pathname from the executable if 594 * possible. (It should always be possible.) That ensures that 595 * gdb will find the right dynamic linker even if a non-standard 596 * one is being used. 597 */ 598 if (obj_main->interp != NULL && 599 strcmp(obj_main->interp, obj_rtld.path) != 0) { 600 free(obj_rtld.path); 601 obj_rtld.path = xstrdup(obj_main->interp); 602 __progname = obj_rtld.path; 603 } 604 #endif 605 606 digest_dynamic(obj_main, 0); 607 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 608 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 609 obj_main->dynsymcount); 610 611 linkmap_add(obj_main); 612 linkmap_add(&obj_rtld); 613 614 /* Link the main program into the list of objects. */ 615 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 616 obj_count++; 617 obj_loads++; 618 619 /* Initialize a fake symbol for resolving undefined weak references. */ 620 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 621 sym_zero.st_shndx = SHN_UNDEF; 622 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 623 624 if (!libmap_disable) 625 libmap_disable = (bool)lm_init(libmap_override); 626 627 dbg("loading LD_PRELOAD libraries"); 628 if (load_preload_objects() == -1) 629 rtld_die(); 630 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 631 632 dbg("loading needed objects"); 633 if (load_needed_objects(obj_main, 0) == -1) 634 rtld_die(); 635 636 /* Make a list of all objects loaded at startup. */ 637 last_interposer = obj_main; 638 TAILQ_FOREACH(obj, &obj_list, next) { 639 if (obj->marker) 640 continue; 641 if (obj->z_interpose && obj != obj_main) { 642 objlist_put_after(&list_main, last_interposer, obj); 643 last_interposer = obj; 644 } else { 645 objlist_push_tail(&list_main, obj); 646 } 647 obj->refcount++; 648 } 649 650 dbg("checking for required versions"); 651 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 652 rtld_die(); 653 654 if (ld_tracing) { /* We're done */ 655 trace_loaded_objects(obj_main); 656 exit(0); 657 } 658 659 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 660 dump_relocations(obj_main); 661 exit (0); 662 } 663 664 /* 665 * Processing tls relocations requires having the tls offsets 666 * initialized. Prepare offsets before starting initial 667 * relocation processing. 668 */ 669 dbg("initializing initial thread local storage offsets"); 670 STAILQ_FOREACH(entry, &list_main, link) { 671 /* 672 * Allocate all the initial objects out of the static TLS 673 * block even if they didn't ask for it. 674 */ 675 allocate_tls_offset(entry->obj); 676 } 677 678 if (relocate_objects(obj_main, 679 ld_bind_now != NULL && *ld_bind_now != '\0', 680 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 681 rtld_die(); 682 683 dbg("doing copy relocations"); 684 if (do_copy_relocations(obj_main) == -1) 685 rtld_die(); 686 687 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 688 dump_relocations(obj_main); 689 exit (0); 690 } 691 692 ifunc_init(aux); 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); 715 716 dbg("resolving ifuncs"); 717 if (resolve_objects_ifunc(obj_main, 718 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 719 NULL) == -1) 720 rtld_die(); 721 722 dbg("enforcing main obj relro"); 723 if (obj_enforce_relro(obj_main) == -1) 724 rtld_die(); 725 726 if (!obj_main->crt_no_init) { 727 /* 728 * Make sure we don't call the main program's init and fini 729 * functions for binaries linked with old crt1 which calls 730 * _init itself. 731 */ 732 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 733 obj_main->preinit_array = obj_main->init_array = 734 obj_main->fini_array = (Elf_Addr)NULL; 735 } 736 737 /* 738 * Execute MD initializers required before we call the objects' 739 * init functions. 740 */ 741 pre_init(); 742 743 wlock_acquire(rtld_bind_lock, &lockstate); 744 if (obj_main->crt_no_init) 745 preinit_main(); 746 objlist_call_init(&initlist, &lockstate); 747 _r_debug_postinit(&obj_main->linkmap); 748 objlist_clear(&initlist); 749 dbg("loading filtees"); 750 TAILQ_FOREACH(obj, &obj_list, next) { 751 if (obj->marker) 752 continue; 753 if (ld_loadfltr || obj->z_loadfltr) 754 load_filtees(obj, 0, &lockstate); 755 } 756 lock_release(rtld_bind_lock, &lockstate); 757 758 dbg("transferring control to program entry point = %p", obj_main->entry); 759 760 /* Return the exit procedure and the program entry point. */ 761 *exit_proc = rtld_exit; 762 *objp = obj_main; 763 return (func_ptr_type) obj_main->entry; 764 } 765 766 void * 767 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 768 { 769 void *ptr; 770 Elf_Addr target; 771 772 ptr = (void *)make_function_pointer(def, obj); 773 target = call_ifunc_resolver(ptr); 774 return ((void *)target); 775 } 776 777 /* 778 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 779 * Changes to this function should be applied there as well. 780 */ 781 Elf_Addr 782 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 783 { 784 const Elf_Rel *rel; 785 const Elf_Sym *def; 786 const Obj_Entry *defobj; 787 Elf_Addr *where; 788 Elf_Addr target; 789 RtldLockState lockstate; 790 791 rlock_acquire(rtld_bind_lock, &lockstate); 792 if (sigsetjmp(lockstate.env, 0) != 0) 793 lock_upgrade(rtld_bind_lock, &lockstate); 794 if (obj->pltrel) 795 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 796 else 797 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 798 799 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 800 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 801 NULL, &lockstate); 802 if (def == NULL) 803 rtld_die(); 804 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 805 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 806 else 807 target = (Elf_Addr)(defobj->relocbase + def->st_value); 808 809 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 810 defobj->strtab + def->st_name, basename(obj->path), 811 (void *)target, basename(defobj->path)); 812 813 /* 814 * Write the new contents for the jmpslot. Note that depending on 815 * architecture, the value which we need to return back to the 816 * lazy binding trampoline may or may not be the target 817 * address. The value returned from reloc_jmpslot() is the value 818 * that the trampoline needs. 819 */ 820 target = reloc_jmpslot(where, target, defobj, obj, rel); 821 lock_release(rtld_bind_lock, &lockstate); 822 return target; 823 } 824 825 /* 826 * Error reporting function. Use it like printf. If formats the message 827 * into a buffer, and sets things up so that the next call to dlerror() 828 * will return the message. 829 */ 830 void 831 _rtld_error(const char *fmt, ...) 832 { 833 static char buf[512]; 834 va_list ap; 835 836 va_start(ap, fmt); 837 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 838 error_message = buf; 839 va_end(ap); 840 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 841 } 842 843 /* 844 * Return a dynamically-allocated copy of the current error message, if any. 845 */ 846 static char * 847 errmsg_save(void) 848 { 849 return error_message == NULL ? NULL : xstrdup(error_message); 850 } 851 852 /* 853 * Restore the current error message from a copy which was previously saved 854 * by errmsg_save(). The copy is freed. 855 */ 856 static void 857 errmsg_restore(char *saved_msg) 858 { 859 if (saved_msg == NULL) 860 error_message = NULL; 861 else { 862 _rtld_error("%s", saved_msg); 863 free(saved_msg); 864 } 865 } 866 867 static const char * 868 basename(const char *name) 869 { 870 const char *p = strrchr(name, '/'); 871 return p != NULL ? p + 1 : name; 872 } 873 874 static struct utsname uts; 875 876 static char * 877 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 878 const char *subst, bool may_free) 879 { 880 char *p, *p1, *res, *resp; 881 int subst_len, kw_len, subst_count, old_len, new_len; 882 883 kw_len = strlen(kw); 884 885 /* 886 * First, count the number of the keyword occurrences, to 887 * preallocate the final string. 888 */ 889 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 890 p1 = strstr(p, kw); 891 if (p1 == NULL) 892 break; 893 } 894 895 /* 896 * If the keyword is not found, just return. 897 * 898 * Return non-substituted string if resolution failed. We 899 * cannot do anything more reasonable, the failure mode of the 900 * caller is unresolved library anyway. 901 */ 902 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 903 return (may_free ? real : xstrdup(real)); 904 if (obj != NULL) 905 subst = obj->origin_path; 906 907 /* 908 * There is indeed something to substitute. Calculate the 909 * length of the resulting string, and allocate it. 910 */ 911 subst_len = strlen(subst); 912 old_len = strlen(real); 913 new_len = old_len + (subst_len - kw_len) * subst_count; 914 res = xmalloc(new_len + 1); 915 916 /* 917 * Now, execute the substitution loop. 918 */ 919 for (p = real, resp = res, *resp = '\0';;) { 920 p1 = strstr(p, kw); 921 if (p1 != NULL) { 922 /* Copy the prefix before keyword. */ 923 memcpy(resp, p, p1 - p); 924 resp += p1 - p; 925 /* Keyword replacement. */ 926 memcpy(resp, subst, subst_len); 927 resp += subst_len; 928 *resp = '\0'; 929 p = p1 + kw_len; 930 } else 931 break; 932 } 933 934 /* Copy to the end of string and finish. */ 935 strcat(resp, p); 936 if (may_free) 937 free(real); 938 return (res); 939 } 940 941 static char * 942 origin_subst(Obj_Entry *obj, char *real) 943 { 944 char *res1, *res2, *res3, *res4; 945 946 if (obj == NULL || !trust) 947 return (xstrdup(real)); 948 if (uts.sysname[0] == '\0') { 949 if (uname(&uts) != 0) { 950 _rtld_error("utsname failed: %d", errno); 951 return (NULL); 952 } 953 } 954 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 955 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 956 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 957 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 958 return (res4); 959 } 960 961 void 962 rtld_die(void) 963 { 964 const char *msg = dlerror(); 965 966 if (msg == NULL) 967 msg = "Fatal error"; 968 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 969 rtld_fdputstr(STDERR_FILENO, msg); 970 rtld_fdputchar(STDERR_FILENO, '\n'); 971 _exit(1); 972 } 973 974 /* 975 * Process a shared object's DYNAMIC section, and save the important 976 * information in its Obj_Entry structure. 977 */ 978 static void 979 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 980 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 981 { 982 const Elf_Dyn *dynp; 983 Needed_Entry **needed_tail = &obj->needed; 984 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 985 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 986 const Elf_Hashelt *hashtab; 987 const Elf32_Word *hashval; 988 Elf32_Word bkt, nmaskwords; 989 int bloom_size32; 990 int plttype = DT_REL; 991 992 *dyn_rpath = NULL; 993 *dyn_soname = NULL; 994 *dyn_runpath = NULL; 995 996 obj->bind_now = false; 997 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 998 switch (dynp->d_tag) { 999 1000 case DT_REL: 1001 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1002 break; 1003 1004 case DT_RELSZ: 1005 obj->relsize = dynp->d_un.d_val; 1006 break; 1007 1008 case DT_RELENT: 1009 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1010 break; 1011 1012 case DT_JMPREL: 1013 obj->pltrel = (const Elf_Rel *) 1014 (obj->relocbase + dynp->d_un.d_ptr); 1015 break; 1016 1017 case DT_PLTRELSZ: 1018 obj->pltrelsize = dynp->d_un.d_val; 1019 break; 1020 1021 case DT_RELA: 1022 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1023 break; 1024 1025 case DT_RELASZ: 1026 obj->relasize = dynp->d_un.d_val; 1027 break; 1028 1029 case DT_RELAENT: 1030 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1031 break; 1032 1033 case DT_PLTREL: 1034 plttype = dynp->d_un.d_val; 1035 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1036 break; 1037 1038 case DT_SYMTAB: 1039 obj->symtab = (const Elf_Sym *) 1040 (obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_SYMENT: 1044 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1045 break; 1046 1047 case DT_STRTAB: 1048 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1049 break; 1050 1051 case DT_STRSZ: 1052 obj->strsize = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_VERNEED: 1056 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1057 dynp->d_un.d_val); 1058 break; 1059 1060 case DT_VERNEEDNUM: 1061 obj->verneednum = dynp->d_un.d_val; 1062 break; 1063 1064 case DT_VERDEF: 1065 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1066 dynp->d_un.d_val); 1067 break; 1068 1069 case DT_VERDEFNUM: 1070 obj->verdefnum = dynp->d_un.d_val; 1071 break; 1072 1073 case DT_VERSYM: 1074 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1075 dynp->d_un.d_val); 1076 break; 1077 1078 case DT_HASH: 1079 { 1080 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1081 dynp->d_un.d_ptr); 1082 obj->nbuckets = hashtab[0]; 1083 obj->nchains = hashtab[1]; 1084 obj->buckets = hashtab + 2; 1085 obj->chains = obj->buckets + obj->nbuckets; 1086 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1087 obj->buckets != NULL; 1088 } 1089 break; 1090 1091 case DT_GNU_HASH: 1092 { 1093 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1094 dynp->d_un.d_ptr); 1095 obj->nbuckets_gnu = hashtab[0]; 1096 obj->symndx_gnu = hashtab[1]; 1097 nmaskwords = hashtab[2]; 1098 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1099 obj->maskwords_bm_gnu = nmaskwords - 1; 1100 obj->shift2_gnu = hashtab[3]; 1101 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1102 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1103 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1104 obj->symndx_gnu; 1105 /* Number of bitmask words is required to be power of 2 */ 1106 obj->valid_hash_gnu = powerof2(nmaskwords) && 1107 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1108 } 1109 break; 1110 1111 case DT_NEEDED: 1112 if (!obj->rtld) { 1113 Needed_Entry *nep = NEW(Needed_Entry); 1114 nep->name = dynp->d_un.d_val; 1115 nep->obj = NULL; 1116 nep->next = NULL; 1117 1118 *needed_tail = nep; 1119 needed_tail = &nep->next; 1120 } 1121 break; 1122 1123 case DT_FILTER: 1124 if (!obj->rtld) { 1125 Needed_Entry *nep = NEW(Needed_Entry); 1126 nep->name = dynp->d_un.d_val; 1127 nep->obj = NULL; 1128 nep->next = NULL; 1129 1130 *needed_filtees_tail = nep; 1131 needed_filtees_tail = &nep->next; 1132 } 1133 break; 1134 1135 case DT_AUXILIARY: 1136 if (!obj->rtld) { 1137 Needed_Entry *nep = NEW(Needed_Entry); 1138 nep->name = dynp->d_un.d_val; 1139 nep->obj = NULL; 1140 nep->next = NULL; 1141 1142 *needed_aux_filtees_tail = nep; 1143 needed_aux_filtees_tail = &nep->next; 1144 } 1145 break; 1146 1147 case DT_PLTGOT: 1148 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1149 break; 1150 1151 case DT_TEXTREL: 1152 obj->textrel = true; 1153 break; 1154 1155 case DT_SYMBOLIC: 1156 obj->symbolic = true; 1157 break; 1158 1159 case DT_RPATH: 1160 /* 1161 * We have to wait until later to process this, because we 1162 * might not have gotten the address of the string table yet. 1163 */ 1164 *dyn_rpath = dynp; 1165 break; 1166 1167 case DT_SONAME: 1168 *dyn_soname = dynp; 1169 break; 1170 1171 case DT_RUNPATH: 1172 *dyn_runpath = dynp; 1173 break; 1174 1175 case DT_INIT: 1176 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1177 break; 1178 1179 case DT_PREINIT_ARRAY: 1180 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1181 break; 1182 1183 case DT_PREINIT_ARRAYSZ: 1184 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1185 break; 1186 1187 case DT_INIT_ARRAY: 1188 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1189 break; 1190 1191 case DT_INIT_ARRAYSZ: 1192 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1193 break; 1194 1195 case DT_FINI: 1196 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1197 break; 1198 1199 case DT_FINI_ARRAY: 1200 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1201 break; 1202 1203 case DT_FINI_ARRAYSZ: 1204 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1205 break; 1206 1207 /* 1208 * Don't process DT_DEBUG on MIPS as the dynamic section 1209 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1210 */ 1211 1212 #ifndef __mips__ 1213 case DT_DEBUG: 1214 if (!early) 1215 dbg("Filling in DT_DEBUG entry"); 1216 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1217 break; 1218 #endif 1219 1220 case DT_FLAGS: 1221 if (dynp->d_un.d_val & DF_ORIGIN) 1222 obj->z_origin = true; 1223 if (dynp->d_un.d_val & DF_SYMBOLIC) 1224 obj->symbolic = true; 1225 if (dynp->d_un.d_val & DF_TEXTREL) 1226 obj->textrel = true; 1227 if (dynp->d_un.d_val & DF_BIND_NOW) 1228 obj->bind_now = true; 1229 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1230 ;*/ 1231 break; 1232 #ifdef __mips__ 1233 case DT_MIPS_LOCAL_GOTNO: 1234 obj->local_gotno = dynp->d_un.d_val; 1235 break; 1236 1237 case DT_MIPS_SYMTABNO: 1238 obj->symtabno = dynp->d_un.d_val; 1239 break; 1240 1241 case DT_MIPS_GOTSYM: 1242 obj->gotsym = dynp->d_un.d_val; 1243 break; 1244 1245 case DT_MIPS_RLD_MAP: 1246 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1247 break; 1248 1249 case DT_MIPS_PLTGOT: 1250 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1251 dynp->d_un.d_ptr); 1252 break; 1253 1254 #endif 1255 1256 #ifdef __powerpc64__ 1257 case DT_PPC64_GLINK: 1258 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1259 break; 1260 #endif 1261 1262 case DT_FLAGS_1: 1263 if (dynp->d_un.d_val & DF_1_NOOPEN) 1264 obj->z_noopen = true; 1265 if (dynp->d_un.d_val & DF_1_ORIGIN) 1266 obj->z_origin = true; 1267 if (dynp->d_un.d_val & DF_1_GLOBAL) 1268 obj->z_global = true; 1269 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1270 obj->bind_now = true; 1271 if (dynp->d_un.d_val & DF_1_NODELETE) 1272 obj->z_nodelete = true; 1273 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1274 obj->z_loadfltr = true; 1275 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1276 obj->z_interpose = true; 1277 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1278 obj->z_nodeflib = true; 1279 break; 1280 1281 default: 1282 if (!early) { 1283 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1284 (long)dynp->d_tag); 1285 } 1286 break; 1287 } 1288 } 1289 1290 obj->traced = false; 1291 1292 if (plttype == DT_RELA) { 1293 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1294 obj->pltrel = NULL; 1295 obj->pltrelasize = obj->pltrelsize; 1296 obj->pltrelsize = 0; 1297 } 1298 1299 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1300 if (obj->valid_hash_sysv) 1301 obj->dynsymcount = obj->nchains; 1302 else if (obj->valid_hash_gnu) { 1303 obj->dynsymcount = 0; 1304 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1305 if (obj->buckets_gnu[bkt] == 0) 1306 continue; 1307 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1308 do 1309 obj->dynsymcount++; 1310 while ((*hashval++ & 1u) == 0); 1311 } 1312 obj->dynsymcount += obj->symndx_gnu; 1313 } 1314 } 1315 1316 static bool 1317 obj_resolve_origin(Obj_Entry *obj) 1318 { 1319 1320 if (obj->origin_path != NULL) 1321 return (true); 1322 obj->origin_path = xmalloc(PATH_MAX); 1323 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1324 } 1325 1326 static void 1327 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1328 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1329 { 1330 1331 if (obj->z_origin && !obj_resolve_origin(obj)) 1332 rtld_die(); 1333 1334 if (dyn_runpath != NULL) { 1335 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1336 obj->runpath = origin_subst(obj, obj->runpath); 1337 } else if (dyn_rpath != NULL) { 1338 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1339 obj->rpath = origin_subst(obj, obj->rpath); 1340 } 1341 if (dyn_soname != NULL) 1342 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1343 } 1344 1345 static void 1346 digest_dynamic(Obj_Entry *obj, int early) 1347 { 1348 const Elf_Dyn *dyn_rpath; 1349 const Elf_Dyn *dyn_soname; 1350 const Elf_Dyn *dyn_runpath; 1351 1352 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1353 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1354 } 1355 1356 /* 1357 * Process a shared object's program header. This is used only for the 1358 * main program, when the kernel has already loaded the main program 1359 * into memory before calling the dynamic linker. It creates and 1360 * returns an Obj_Entry structure. 1361 */ 1362 static Obj_Entry * 1363 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1364 { 1365 Obj_Entry *obj; 1366 const Elf_Phdr *phlimit = phdr + phnum; 1367 const Elf_Phdr *ph; 1368 Elf_Addr note_start, note_end; 1369 int nsegs = 0; 1370 1371 obj = obj_new(); 1372 for (ph = phdr; ph < phlimit; ph++) { 1373 if (ph->p_type != PT_PHDR) 1374 continue; 1375 1376 obj->phdr = phdr; 1377 obj->phsize = ph->p_memsz; 1378 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1379 break; 1380 } 1381 1382 obj->stack_flags = PF_X | PF_R | PF_W; 1383 1384 for (ph = phdr; ph < phlimit; ph++) { 1385 switch (ph->p_type) { 1386 1387 case PT_INTERP: 1388 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1389 break; 1390 1391 case PT_LOAD: 1392 if (nsegs == 0) { /* First load segment */ 1393 obj->vaddrbase = trunc_page(ph->p_vaddr); 1394 obj->mapbase = obj->vaddrbase + obj->relocbase; 1395 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1396 obj->vaddrbase; 1397 } else { /* Last load segment */ 1398 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1399 obj->vaddrbase; 1400 } 1401 nsegs++; 1402 break; 1403 1404 case PT_DYNAMIC: 1405 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1406 break; 1407 1408 case PT_TLS: 1409 obj->tlsindex = 1; 1410 obj->tlssize = ph->p_memsz; 1411 obj->tlsalign = ph->p_align; 1412 obj->tlsinitsize = ph->p_filesz; 1413 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1414 break; 1415 1416 case PT_GNU_STACK: 1417 obj->stack_flags = ph->p_flags; 1418 break; 1419 1420 case PT_GNU_RELRO: 1421 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1422 obj->relro_size = round_page(ph->p_memsz); 1423 break; 1424 1425 case PT_NOTE: 1426 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1427 note_end = note_start + ph->p_filesz; 1428 digest_notes(obj, note_start, note_end); 1429 break; 1430 } 1431 } 1432 if (nsegs < 1) { 1433 _rtld_error("%s: too few PT_LOAD segments", path); 1434 return NULL; 1435 } 1436 1437 obj->entry = entry; 1438 return obj; 1439 } 1440 1441 void 1442 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1443 { 1444 const Elf_Note *note; 1445 const char *note_name; 1446 uintptr_t p; 1447 1448 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1449 note = (const Elf_Note *)((const char *)(note + 1) + 1450 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1451 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1452 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1453 note->n_descsz != sizeof(int32_t)) 1454 continue; 1455 if (note->n_type != NT_FREEBSD_ABI_TAG && 1456 note->n_type != NT_FREEBSD_FEATURE_CTL && 1457 note->n_type != NT_FREEBSD_NOINIT_TAG) 1458 continue; 1459 note_name = (const char *)(note + 1); 1460 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1461 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1462 continue; 1463 switch (note->n_type) { 1464 case NT_FREEBSD_ABI_TAG: 1465 /* FreeBSD osrel note */ 1466 p = (uintptr_t)(note + 1); 1467 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1468 obj->osrel = *(const int32_t *)(p); 1469 dbg("note osrel %d", obj->osrel); 1470 break; 1471 case NT_FREEBSD_FEATURE_CTL: 1472 /* FreeBSD ABI feature control note */ 1473 p = (uintptr_t)(note + 1); 1474 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1475 obj->fctl0 = *(const uint32_t *)(p); 1476 dbg("note fctl0 %#x", obj->fctl0); 1477 break; 1478 case NT_FREEBSD_NOINIT_TAG: 1479 /* FreeBSD 'crt does not call init' note */ 1480 obj->crt_no_init = true; 1481 dbg("note crt_no_init"); 1482 break; 1483 } 1484 } 1485 } 1486 1487 static Obj_Entry * 1488 dlcheck(void *handle) 1489 { 1490 Obj_Entry *obj; 1491 1492 TAILQ_FOREACH(obj, &obj_list, next) { 1493 if (obj == (Obj_Entry *) handle) 1494 break; 1495 } 1496 1497 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1498 _rtld_error("Invalid shared object handle %p", handle); 1499 return NULL; 1500 } 1501 return obj; 1502 } 1503 1504 /* 1505 * If the given object is already in the donelist, return true. Otherwise 1506 * add the object to the list and return false. 1507 */ 1508 static bool 1509 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1510 { 1511 unsigned int i; 1512 1513 for (i = 0; i < dlp->num_used; i++) 1514 if (dlp->objs[i] == obj) 1515 return true; 1516 /* 1517 * Our donelist allocation should always be sufficient. But if 1518 * our threads locking isn't working properly, more shared objects 1519 * could have been loaded since we allocated the list. That should 1520 * never happen, but we'll handle it properly just in case it does. 1521 */ 1522 if (dlp->num_used < dlp->num_alloc) 1523 dlp->objs[dlp->num_used++] = obj; 1524 return false; 1525 } 1526 1527 /* 1528 * Hash function for symbol table lookup. Don't even think about changing 1529 * this. It is specified by the System V ABI. 1530 */ 1531 unsigned long 1532 elf_hash(const char *name) 1533 { 1534 const unsigned char *p = (const unsigned char *) name; 1535 unsigned long h = 0; 1536 unsigned long g; 1537 1538 while (*p != '\0') { 1539 h = (h << 4) + *p++; 1540 if ((g = h & 0xf0000000) != 0) 1541 h ^= g >> 24; 1542 h &= ~g; 1543 } 1544 return h; 1545 } 1546 1547 /* 1548 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1549 * unsigned in case it's implemented with a wider type. 1550 */ 1551 static uint32_t 1552 gnu_hash(const char *s) 1553 { 1554 uint32_t h; 1555 unsigned char c; 1556 1557 h = 5381; 1558 for (c = *s; c != '\0'; c = *++s) 1559 h = h * 33 + c; 1560 return (h & 0xffffffff); 1561 } 1562 1563 1564 /* 1565 * Find the library with the given name, and return its full pathname. 1566 * The returned string is dynamically allocated. Generates an error 1567 * message and returns NULL if the library cannot be found. 1568 * 1569 * If the second argument is non-NULL, then it refers to an already- 1570 * loaded shared object, whose library search path will be searched. 1571 * 1572 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1573 * descriptor (which is close-on-exec) will be passed out via the third 1574 * argument. 1575 * 1576 * The search order is: 1577 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1578 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1579 * LD_LIBRARY_PATH 1580 * DT_RUNPATH in the referencing file 1581 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1582 * from list) 1583 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1584 * 1585 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1586 */ 1587 static char * 1588 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1589 { 1590 char *name, *pathname, *refobj_path; 1591 bool nodeflib, objgiven; 1592 1593 objgiven = refobj != NULL; 1594 1595 if (libmap_disable || !objgiven || 1596 (name = lm_find(refobj->path, xname)) == NULL) 1597 name = (char *)xname; 1598 1599 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1600 if (name[0] != '/' && !trust) { 1601 _rtld_error("Absolute pathname required " 1602 "for shared object \"%s\"", name); 1603 return (NULL); 1604 } 1605 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1606 __DECONST(char *, name))); 1607 } 1608 1609 dbg(" Searching for \"%s\"", name); 1610 refobj_path = objgiven ? refobj->path : NULL; 1611 1612 /* 1613 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1614 * back to pre-conforming behaviour if user requested so with 1615 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1616 * nodeflib. 1617 */ 1618 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1619 pathname = search_library_path(name, ld_library_path, 1620 refobj_path, fdp); 1621 if (pathname != NULL) 1622 return (pathname); 1623 if (refobj != NULL) { 1624 pathname = search_library_path(name, refobj->rpath, 1625 refobj_path, fdp); 1626 if (pathname != NULL) 1627 return (pathname); 1628 } 1629 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1630 if (pathname != NULL) 1631 return (pathname); 1632 pathname = search_library_path(name, gethints(false), 1633 refobj_path, fdp); 1634 if (pathname != NULL) 1635 return (pathname); 1636 pathname = search_library_path(name, ld_standard_library_path, 1637 refobj_path, fdp); 1638 if (pathname != NULL) 1639 return (pathname); 1640 } else { 1641 nodeflib = objgiven ? refobj->z_nodeflib : false; 1642 if (objgiven) { 1643 pathname = search_library_path(name, refobj->rpath, 1644 refobj->path, fdp); 1645 if (pathname != NULL) 1646 return (pathname); 1647 } 1648 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1649 pathname = search_library_path(name, obj_main->rpath, 1650 refobj_path, fdp); 1651 if (pathname != NULL) 1652 return (pathname); 1653 } 1654 pathname = search_library_path(name, ld_library_path, 1655 refobj_path, fdp); 1656 if (pathname != NULL) 1657 return (pathname); 1658 if (objgiven) { 1659 pathname = search_library_path(name, refobj->runpath, 1660 refobj_path, fdp); 1661 if (pathname != NULL) 1662 return (pathname); 1663 } 1664 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1665 if (pathname != NULL) 1666 return (pathname); 1667 pathname = search_library_path(name, gethints(nodeflib), 1668 refobj_path, fdp); 1669 if (pathname != NULL) 1670 return (pathname); 1671 if (objgiven && !nodeflib) { 1672 pathname = search_library_path(name, 1673 ld_standard_library_path, refobj_path, fdp); 1674 if (pathname != NULL) 1675 return (pathname); 1676 } 1677 } 1678 1679 if (objgiven && refobj->path != NULL) { 1680 _rtld_error("Shared object \"%s\" not found, " 1681 "required by \"%s\"", name, basename(refobj->path)); 1682 } else { 1683 _rtld_error("Shared object \"%s\" not found", name); 1684 } 1685 return (NULL); 1686 } 1687 1688 /* 1689 * Given a symbol number in a referencing object, find the corresponding 1690 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1691 * no definition was found. Returns a pointer to the Obj_Entry of the 1692 * defining object via the reference parameter DEFOBJ_OUT. 1693 */ 1694 const Elf_Sym * 1695 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1696 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1697 RtldLockState *lockstate) 1698 { 1699 const Elf_Sym *ref; 1700 const Elf_Sym *def; 1701 const Obj_Entry *defobj; 1702 const Ver_Entry *ve; 1703 SymLook req; 1704 const char *name; 1705 int res; 1706 1707 /* 1708 * If we have already found this symbol, get the information from 1709 * the cache. 1710 */ 1711 if (symnum >= refobj->dynsymcount) 1712 return NULL; /* Bad object */ 1713 if (cache != NULL && cache[symnum].sym != NULL) { 1714 *defobj_out = cache[symnum].obj; 1715 return cache[symnum].sym; 1716 } 1717 1718 ref = refobj->symtab + symnum; 1719 name = refobj->strtab + ref->st_name; 1720 def = NULL; 1721 defobj = NULL; 1722 ve = NULL; 1723 1724 /* 1725 * We don't have to do a full scale lookup if the symbol is local. 1726 * We know it will bind to the instance in this load module; to 1727 * which we already have a pointer (ie ref). By not doing a lookup, 1728 * we not only improve performance, but it also avoids unresolvable 1729 * symbols when local symbols are not in the hash table. This has 1730 * been seen with the ia64 toolchain. 1731 */ 1732 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1733 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1734 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1735 symnum); 1736 } 1737 symlook_init(&req, name); 1738 req.flags = flags; 1739 ve = req.ventry = fetch_ventry(refobj, symnum); 1740 req.lockstate = lockstate; 1741 res = symlook_default(&req, refobj); 1742 if (res == 0) { 1743 def = req.sym_out; 1744 defobj = req.defobj_out; 1745 } 1746 } else { 1747 def = ref; 1748 defobj = refobj; 1749 } 1750 1751 /* 1752 * If we found no definition and the reference is weak, treat the 1753 * symbol as having the value zero. 1754 */ 1755 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1756 def = &sym_zero; 1757 defobj = obj_main; 1758 } 1759 1760 if (def != NULL) { 1761 *defobj_out = defobj; 1762 /* Record the information in the cache to avoid subsequent lookups. */ 1763 if (cache != NULL) { 1764 cache[symnum].sym = def; 1765 cache[symnum].obj = defobj; 1766 } 1767 } else { 1768 if (refobj != &obj_rtld) 1769 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1770 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1771 } 1772 return def; 1773 } 1774 1775 /* 1776 * Return the search path from the ldconfig hints file, reading it if 1777 * necessary. If nostdlib is true, then the default search paths are 1778 * not added to result. 1779 * 1780 * Returns NULL if there are problems with the hints file, 1781 * or if the search path there is empty. 1782 */ 1783 static const char * 1784 gethints(bool nostdlib) 1785 { 1786 static char *hints, *filtered_path; 1787 static struct elfhints_hdr hdr; 1788 struct fill_search_info_args sargs, hargs; 1789 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1790 struct dl_serpath *SLPpath, *hintpath; 1791 char *p; 1792 struct stat hint_stat; 1793 unsigned int SLPndx, hintndx, fndx, fcount; 1794 int fd; 1795 size_t flen; 1796 uint32_t dl; 1797 bool skip; 1798 1799 /* First call, read the hints file */ 1800 if (hints == NULL) { 1801 /* Keep from trying again in case the hints file is bad. */ 1802 hints = ""; 1803 1804 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1805 return (NULL); 1806 1807 /* 1808 * Check of hdr.dirlistlen value against type limit 1809 * intends to pacify static analyzers. Further 1810 * paranoia leads to checks that dirlist is fully 1811 * contained in the file range. 1812 */ 1813 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1814 hdr.magic != ELFHINTS_MAGIC || 1815 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1816 fstat(fd, &hint_stat) == -1) { 1817 cleanup1: 1818 close(fd); 1819 hdr.dirlistlen = 0; 1820 return (NULL); 1821 } 1822 dl = hdr.strtab; 1823 if (dl + hdr.dirlist < dl) 1824 goto cleanup1; 1825 dl += hdr.dirlist; 1826 if (dl + hdr.dirlistlen < dl) 1827 goto cleanup1; 1828 dl += hdr.dirlistlen; 1829 if (dl > hint_stat.st_size) 1830 goto cleanup1; 1831 p = xmalloc(hdr.dirlistlen + 1); 1832 if (pread(fd, p, hdr.dirlistlen + 1, 1833 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1834 p[hdr.dirlistlen] != '\0') { 1835 free(p); 1836 goto cleanup1; 1837 } 1838 hints = p; 1839 close(fd); 1840 } 1841 1842 /* 1843 * If caller agreed to receive list which includes the default 1844 * paths, we are done. Otherwise, if we still did not 1845 * calculated filtered result, do it now. 1846 */ 1847 if (!nostdlib) 1848 return (hints[0] != '\0' ? hints : NULL); 1849 if (filtered_path != NULL) 1850 goto filt_ret; 1851 1852 /* 1853 * Obtain the list of all configured search paths, and the 1854 * list of the default paths. 1855 * 1856 * First estimate the size of the results. 1857 */ 1858 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1859 smeta.dls_cnt = 0; 1860 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1861 hmeta.dls_cnt = 0; 1862 1863 sargs.request = RTLD_DI_SERINFOSIZE; 1864 sargs.serinfo = &smeta; 1865 hargs.request = RTLD_DI_SERINFOSIZE; 1866 hargs.serinfo = &hmeta; 1867 1868 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1869 &sargs); 1870 path_enumerate(hints, fill_search_info, NULL, &hargs); 1871 1872 SLPinfo = xmalloc(smeta.dls_size); 1873 hintinfo = xmalloc(hmeta.dls_size); 1874 1875 /* 1876 * Next fetch both sets of paths. 1877 */ 1878 sargs.request = RTLD_DI_SERINFO; 1879 sargs.serinfo = SLPinfo; 1880 sargs.serpath = &SLPinfo->dls_serpath[0]; 1881 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1882 1883 hargs.request = RTLD_DI_SERINFO; 1884 hargs.serinfo = hintinfo; 1885 hargs.serpath = &hintinfo->dls_serpath[0]; 1886 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1887 1888 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1889 &sargs); 1890 path_enumerate(hints, fill_search_info, NULL, &hargs); 1891 1892 /* 1893 * Now calculate the difference between two sets, by excluding 1894 * standard paths from the full set. 1895 */ 1896 fndx = 0; 1897 fcount = 0; 1898 filtered_path = xmalloc(hdr.dirlistlen + 1); 1899 hintpath = &hintinfo->dls_serpath[0]; 1900 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1901 skip = false; 1902 SLPpath = &SLPinfo->dls_serpath[0]; 1903 /* 1904 * Check each standard path against current. 1905 */ 1906 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1907 /* matched, skip the path */ 1908 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1909 skip = true; 1910 break; 1911 } 1912 } 1913 if (skip) 1914 continue; 1915 /* 1916 * Not matched against any standard path, add the path 1917 * to result. Separate consequtive paths with ':'. 1918 */ 1919 if (fcount > 0) { 1920 filtered_path[fndx] = ':'; 1921 fndx++; 1922 } 1923 fcount++; 1924 flen = strlen(hintpath->dls_name); 1925 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1926 fndx += flen; 1927 } 1928 filtered_path[fndx] = '\0'; 1929 1930 free(SLPinfo); 1931 free(hintinfo); 1932 1933 filt_ret: 1934 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1935 } 1936 1937 static void 1938 init_dag(Obj_Entry *root) 1939 { 1940 const Needed_Entry *needed; 1941 const Objlist_Entry *elm; 1942 DoneList donelist; 1943 1944 if (root->dag_inited) 1945 return; 1946 donelist_init(&donelist); 1947 1948 /* Root object belongs to own DAG. */ 1949 objlist_push_tail(&root->dldags, root); 1950 objlist_push_tail(&root->dagmembers, root); 1951 donelist_check(&donelist, root); 1952 1953 /* 1954 * Add dependencies of root object to DAG in breadth order 1955 * by exploiting the fact that each new object get added 1956 * to the tail of the dagmembers list. 1957 */ 1958 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1959 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1960 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1961 continue; 1962 objlist_push_tail(&needed->obj->dldags, root); 1963 objlist_push_tail(&root->dagmembers, needed->obj); 1964 } 1965 } 1966 root->dag_inited = true; 1967 } 1968 1969 static void 1970 init_marker(Obj_Entry *marker) 1971 { 1972 1973 bzero(marker, sizeof(*marker)); 1974 marker->marker = true; 1975 } 1976 1977 Obj_Entry * 1978 globallist_curr(const Obj_Entry *obj) 1979 { 1980 1981 for (;;) { 1982 if (obj == NULL) 1983 return (NULL); 1984 if (!obj->marker) 1985 return (__DECONST(Obj_Entry *, obj)); 1986 obj = TAILQ_PREV(obj, obj_entry_q, next); 1987 } 1988 } 1989 1990 Obj_Entry * 1991 globallist_next(const Obj_Entry *obj) 1992 { 1993 1994 for (;;) { 1995 obj = TAILQ_NEXT(obj, next); 1996 if (obj == NULL) 1997 return (NULL); 1998 if (!obj->marker) 1999 return (__DECONST(Obj_Entry *, obj)); 2000 } 2001 } 2002 2003 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2004 static void 2005 hold_object(Obj_Entry *obj) 2006 { 2007 2008 obj->holdcount++; 2009 } 2010 2011 static void 2012 unhold_object(Obj_Entry *obj) 2013 { 2014 2015 assert(obj->holdcount > 0); 2016 if (--obj->holdcount == 0 && obj->unholdfree) 2017 release_object(obj); 2018 } 2019 2020 static void 2021 process_z(Obj_Entry *root) 2022 { 2023 const Objlist_Entry *elm; 2024 Obj_Entry *obj; 2025 2026 /* 2027 * Walk over object DAG and process every dependent object 2028 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2029 * to grow their own DAG. 2030 * 2031 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2032 * symlook_global() to work. 2033 * 2034 * For DF_1_NODELETE, the DAG should have its reference upped. 2035 */ 2036 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2037 obj = elm->obj; 2038 if (obj == NULL) 2039 continue; 2040 if (obj->z_nodelete && !obj->ref_nodel) { 2041 dbg("obj %s -z nodelete", obj->path); 2042 init_dag(obj); 2043 ref_dag(obj); 2044 obj->ref_nodel = true; 2045 } 2046 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2047 dbg("obj %s -z global", obj->path); 2048 objlist_push_tail(&list_global, obj); 2049 init_dag(obj); 2050 } 2051 } 2052 } 2053 /* 2054 * Initialize the dynamic linker. The argument is the address at which 2055 * the dynamic linker has been mapped into memory. The primary task of 2056 * this function is to relocate the dynamic linker. 2057 */ 2058 static void 2059 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2060 { 2061 Obj_Entry objtmp; /* Temporary rtld object */ 2062 const Elf_Ehdr *ehdr; 2063 const Elf_Dyn *dyn_rpath; 2064 const Elf_Dyn *dyn_soname; 2065 const Elf_Dyn *dyn_runpath; 2066 2067 #ifdef RTLD_INIT_PAGESIZES_EARLY 2068 /* The page size is required by the dynamic memory allocator. */ 2069 init_pagesizes(aux_info); 2070 #endif 2071 2072 /* 2073 * Conjure up an Obj_Entry structure for the dynamic linker. 2074 * 2075 * The "path" member can't be initialized yet because string constants 2076 * cannot yet be accessed. Below we will set it correctly. 2077 */ 2078 memset(&objtmp, 0, sizeof(objtmp)); 2079 objtmp.path = NULL; 2080 objtmp.rtld = true; 2081 objtmp.mapbase = mapbase; 2082 #ifdef PIC 2083 objtmp.relocbase = mapbase; 2084 #endif 2085 2086 objtmp.dynamic = rtld_dynamic(&objtmp); 2087 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2088 assert(objtmp.needed == NULL); 2089 #if !defined(__mips__) 2090 /* MIPS has a bogus DT_TEXTREL. */ 2091 assert(!objtmp.textrel); 2092 #endif 2093 /* 2094 * Temporarily put the dynamic linker entry into the object list, so 2095 * that symbols can be found. 2096 */ 2097 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2098 2099 ehdr = (Elf_Ehdr *)mapbase; 2100 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2101 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2102 2103 /* Initialize the object list. */ 2104 TAILQ_INIT(&obj_list); 2105 2106 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2107 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2108 2109 #ifndef RTLD_INIT_PAGESIZES_EARLY 2110 /* The page size is required by the dynamic memory allocator. */ 2111 init_pagesizes(aux_info); 2112 #endif 2113 2114 if (aux_info[AT_OSRELDATE] != NULL) 2115 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2116 2117 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2118 2119 /* Replace the path with a dynamically allocated copy. */ 2120 obj_rtld.path = xstrdup(ld_path_rtld); 2121 2122 r_debug.r_brk = r_debug_state; 2123 r_debug.r_state = RT_CONSISTENT; 2124 } 2125 2126 /* 2127 * Retrieve the array of supported page sizes. The kernel provides the page 2128 * sizes in increasing order. 2129 */ 2130 static void 2131 init_pagesizes(Elf_Auxinfo **aux_info) 2132 { 2133 static size_t psa[MAXPAGESIZES]; 2134 int mib[2]; 2135 size_t len, size; 2136 2137 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2138 NULL) { 2139 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2140 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2141 } else { 2142 len = 2; 2143 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2144 size = sizeof(psa); 2145 else { 2146 /* As a fallback, retrieve the base page size. */ 2147 size = sizeof(psa[0]); 2148 if (aux_info[AT_PAGESZ] != NULL) { 2149 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2150 goto psa_filled; 2151 } else { 2152 mib[0] = CTL_HW; 2153 mib[1] = HW_PAGESIZE; 2154 len = 2; 2155 } 2156 } 2157 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2158 _rtld_error("sysctl for hw.pagesize(s) failed"); 2159 rtld_die(); 2160 } 2161 psa_filled: 2162 pagesizes = psa; 2163 } 2164 npagesizes = size / sizeof(pagesizes[0]); 2165 /* Discard any invalid entries at the end of the array. */ 2166 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2167 npagesizes--; 2168 } 2169 2170 /* 2171 * Add the init functions from a needed object list (and its recursive 2172 * needed objects) to "list". This is not used directly; it is a helper 2173 * function for initlist_add_objects(). The write lock must be held 2174 * when this function is called. 2175 */ 2176 static void 2177 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2178 { 2179 /* Recursively process the successor needed objects. */ 2180 if (needed->next != NULL) 2181 initlist_add_neededs(needed->next, list); 2182 2183 /* Process the current needed object. */ 2184 if (needed->obj != NULL) 2185 initlist_add_objects(needed->obj, needed->obj, list); 2186 } 2187 2188 /* 2189 * Scan all of the DAGs rooted in the range of objects from "obj" to 2190 * "tail" and add their init functions to "list". This recurses over 2191 * the DAGs and ensure the proper init ordering such that each object's 2192 * needed libraries are initialized before the object itself. At the 2193 * same time, this function adds the objects to the global finalization 2194 * list "list_fini" in the opposite order. The write lock must be 2195 * held when this function is called. 2196 */ 2197 static void 2198 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2199 { 2200 Obj_Entry *nobj; 2201 2202 if (obj->init_scanned || obj->init_done) 2203 return; 2204 obj->init_scanned = true; 2205 2206 /* Recursively process the successor objects. */ 2207 nobj = globallist_next(obj); 2208 if (nobj != NULL && obj != tail) 2209 initlist_add_objects(nobj, tail, list); 2210 2211 /* Recursively process the needed objects. */ 2212 if (obj->needed != NULL) 2213 initlist_add_neededs(obj->needed, list); 2214 if (obj->needed_filtees != NULL) 2215 initlist_add_neededs(obj->needed_filtees, list); 2216 if (obj->needed_aux_filtees != NULL) 2217 initlist_add_neededs(obj->needed_aux_filtees, list); 2218 2219 /* Add the object to the init list. */ 2220 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2221 obj->init_array != (Elf_Addr)NULL) 2222 objlist_push_tail(list, obj); 2223 2224 /* Add the object to the global fini list in the reverse order. */ 2225 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2226 && !obj->on_fini_list) { 2227 objlist_push_head(&list_fini, obj); 2228 obj->on_fini_list = true; 2229 } 2230 } 2231 2232 #ifndef FPTR_TARGET 2233 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2234 #endif 2235 2236 static void 2237 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2238 { 2239 Needed_Entry *needed, *needed1; 2240 2241 for (needed = n; needed != NULL; needed = needed->next) { 2242 if (needed->obj != NULL) { 2243 dlclose_locked(needed->obj, lockstate); 2244 needed->obj = NULL; 2245 } 2246 } 2247 for (needed = n; needed != NULL; needed = needed1) { 2248 needed1 = needed->next; 2249 free(needed); 2250 } 2251 } 2252 2253 static void 2254 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2255 { 2256 2257 free_needed_filtees(obj->needed_filtees, lockstate); 2258 obj->needed_filtees = NULL; 2259 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2260 obj->needed_aux_filtees = NULL; 2261 obj->filtees_loaded = false; 2262 } 2263 2264 static void 2265 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2266 RtldLockState *lockstate) 2267 { 2268 2269 for (; needed != NULL; needed = needed->next) { 2270 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2271 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2272 RTLD_LOCAL, lockstate); 2273 } 2274 } 2275 2276 static void 2277 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2278 { 2279 2280 lock_restart_for_upgrade(lockstate); 2281 if (!obj->filtees_loaded) { 2282 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2283 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2284 obj->filtees_loaded = true; 2285 } 2286 } 2287 2288 static int 2289 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2290 { 2291 Obj_Entry *obj1; 2292 2293 for (; needed != NULL; needed = needed->next) { 2294 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2295 flags & ~RTLD_LO_NOLOAD); 2296 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2297 return (-1); 2298 } 2299 return (0); 2300 } 2301 2302 /* 2303 * Given a shared object, traverse its list of needed objects, and load 2304 * each of them. Returns 0 on success. Generates an error message and 2305 * returns -1 on failure. 2306 */ 2307 static int 2308 load_needed_objects(Obj_Entry *first, int flags) 2309 { 2310 Obj_Entry *obj; 2311 2312 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2313 if (obj->marker) 2314 continue; 2315 if (process_needed(obj, obj->needed, flags) == -1) 2316 return (-1); 2317 } 2318 return (0); 2319 } 2320 2321 static int 2322 load_preload_objects(void) 2323 { 2324 char *p = ld_preload; 2325 Obj_Entry *obj; 2326 static const char delim[] = " \t:;"; 2327 2328 if (p == NULL) 2329 return 0; 2330 2331 p += strspn(p, delim); 2332 while (*p != '\0') { 2333 size_t len = strcspn(p, delim); 2334 char savech; 2335 2336 savech = p[len]; 2337 p[len] = '\0'; 2338 obj = load_object(p, -1, NULL, 0); 2339 if (obj == NULL) 2340 return -1; /* XXX - cleanup */ 2341 obj->z_interpose = true; 2342 p[len] = savech; 2343 p += len; 2344 p += strspn(p, delim); 2345 } 2346 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2347 return 0; 2348 } 2349 2350 static const char * 2351 printable_path(const char *path) 2352 { 2353 2354 return (path == NULL ? "<unknown>" : path); 2355 } 2356 2357 /* 2358 * Load a shared object into memory, if it is not already loaded. The 2359 * object may be specified by name or by user-supplied file descriptor 2360 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2361 * duplicate is. 2362 * 2363 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2364 * on failure. 2365 */ 2366 static Obj_Entry * 2367 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2368 { 2369 Obj_Entry *obj; 2370 int fd; 2371 struct stat sb; 2372 char *path; 2373 2374 fd = -1; 2375 if (name != NULL) { 2376 TAILQ_FOREACH(obj, &obj_list, next) { 2377 if (obj->marker || obj->doomed) 2378 continue; 2379 if (object_match_name(obj, name)) 2380 return (obj); 2381 } 2382 2383 path = find_library(name, refobj, &fd); 2384 if (path == NULL) 2385 return (NULL); 2386 } else 2387 path = NULL; 2388 2389 if (fd >= 0) { 2390 /* 2391 * search_library_pathfds() opens a fresh file descriptor for the 2392 * library, so there is no need to dup(). 2393 */ 2394 } else if (fd_u == -1) { 2395 /* 2396 * If we didn't find a match by pathname, or the name is not 2397 * supplied, open the file and check again by device and inode. 2398 * This avoids false mismatches caused by multiple links or ".." 2399 * in pathnames. 2400 * 2401 * To avoid a race, we open the file and use fstat() rather than 2402 * using stat(). 2403 */ 2404 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2405 _rtld_error("Cannot open \"%s\"", path); 2406 free(path); 2407 return (NULL); 2408 } 2409 } else { 2410 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2411 if (fd == -1) { 2412 _rtld_error("Cannot dup fd"); 2413 free(path); 2414 return (NULL); 2415 } 2416 } 2417 if (fstat(fd, &sb) == -1) { 2418 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2419 close(fd); 2420 free(path); 2421 return NULL; 2422 } 2423 TAILQ_FOREACH(obj, &obj_list, next) { 2424 if (obj->marker || obj->doomed) 2425 continue; 2426 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2427 break; 2428 } 2429 if (obj != NULL && name != NULL) { 2430 object_add_name(obj, name); 2431 free(path); 2432 close(fd); 2433 return obj; 2434 } 2435 if (flags & RTLD_LO_NOLOAD) { 2436 free(path); 2437 close(fd); 2438 return (NULL); 2439 } 2440 2441 /* First use of this object, so we must map it in */ 2442 obj = do_load_object(fd, name, path, &sb, flags); 2443 if (obj == NULL) 2444 free(path); 2445 close(fd); 2446 2447 return obj; 2448 } 2449 2450 static Obj_Entry * 2451 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2452 int flags) 2453 { 2454 Obj_Entry *obj; 2455 struct statfs fs; 2456 2457 /* 2458 * but first, make sure that environment variables haven't been 2459 * used to circumvent the noexec flag on a filesystem. 2460 */ 2461 if (dangerous_ld_env) { 2462 if (fstatfs(fd, &fs) != 0) { 2463 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2464 return NULL; 2465 } 2466 if (fs.f_flags & MNT_NOEXEC) { 2467 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2468 return NULL; 2469 } 2470 } 2471 dbg("loading \"%s\"", printable_path(path)); 2472 obj = map_object(fd, printable_path(path), sbp); 2473 if (obj == NULL) 2474 return NULL; 2475 2476 /* 2477 * If DT_SONAME is present in the object, digest_dynamic2 already 2478 * added it to the object names. 2479 */ 2480 if (name != NULL) 2481 object_add_name(obj, name); 2482 obj->path = path; 2483 digest_dynamic(obj, 0); 2484 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2485 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2486 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2487 RTLD_LO_DLOPEN) { 2488 dbg("refusing to load non-loadable \"%s\"", obj->path); 2489 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2490 munmap(obj->mapbase, obj->mapsize); 2491 obj_free(obj); 2492 return (NULL); 2493 } 2494 2495 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2496 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2497 obj_count++; 2498 obj_loads++; 2499 linkmap_add(obj); /* for GDB & dlinfo() */ 2500 max_stack_flags |= obj->stack_flags; 2501 2502 dbg(" %p .. %p: %s", obj->mapbase, 2503 obj->mapbase + obj->mapsize - 1, obj->path); 2504 if (obj->textrel) 2505 dbg(" WARNING: %s has impure text", obj->path); 2506 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2507 obj->path); 2508 2509 return obj; 2510 } 2511 2512 static Obj_Entry * 2513 obj_from_addr(const void *addr) 2514 { 2515 Obj_Entry *obj; 2516 2517 TAILQ_FOREACH(obj, &obj_list, next) { 2518 if (obj->marker) 2519 continue; 2520 if (addr < (void *) obj->mapbase) 2521 continue; 2522 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2523 return obj; 2524 } 2525 return NULL; 2526 } 2527 2528 static void 2529 preinit_main(void) 2530 { 2531 Elf_Addr *preinit_addr; 2532 int index; 2533 2534 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2535 if (preinit_addr == NULL) 2536 return; 2537 2538 for (index = 0; index < obj_main->preinit_array_num; index++) { 2539 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2540 dbg("calling preinit function for %s at %p", obj_main->path, 2541 (void *)preinit_addr[index]); 2542 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2543 0, 0, obj_main->path); 2544 call_init_pointer(obj_main, preinit_addr[index]); 2545 } 2546 } 2547 } 2548 2549 /* 2550 * Call the finalization functions for each of the objects in "list" 2551 * belonging to the DAG of "root" and referenced once. If NULL "root" 2552 * is specified, every finalization function will be called regardless 2553 * of the reference count and the list elements won't be freed. All of 2554 * the objects are expected to have non-NULL fini functions. 2555 */ 2556 static void 2557 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2558 { 2559 Objlist_Entry *elm; 2560 char *saved_msg; 2561 Elf_Addr *fini_addr; 2562 int index; 2563 2564 assert(root == NULL || root->refcount == 1); 2565 2566 if (root != NULL) 2567 root->doomed = true; 2568 2569 /* 2570 * Preserve the current error message since a fini function might 2571 * call into the dynamic linker and overwrite it. 2572 */ 2573 saved_msg = errmsg_save(); 2574 do { 2575 STAILQ_FOREACH(elm, list, link) { 2576 if (root != NULL && (elm->obj->refcount != 1 || 2577 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2578 continue; 2579 /* Remove object from fini list to prevent recursive invocation. */ 2580 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2581 /* Ensure that new references cannot be acquired. */ 2582 elm->obj->doomed = true; 2583 2584 hold_object(elm->obj); 2585 lock_release(rtld_bind_lock, lockstate); 2586 /* 2587 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2588 * When this happens, DT_FINI_ARRAY is processed first. 2589 */ 2590 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2591 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2592 for (index = elm->obj->fini_array_num - 1; index >= 0; 2593 index--) { 2594 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2595 dbg("calling fini function for %s at %p", 2596 elm->obj->path, (void *)fini_addr[index]); 2597 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2598 (void *)fini_addr[index], 0, 0, elm->obj->path); 2599 call_initfini_pointer(elm->obj, fini_addr[index]); 2600 } 2601 } 2602 } 2603 if (elm->obj->fini != (Elf_Addr)NULL) { 2604 dbg("calling fini function for %s at %p", elm->obj->path, 2605 (void *)elm->obj->fini); 2606 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2607 0, 0, elm->obj->path); 2608 call_initfini_pointer(elm->obj, elm->obj->fini); 2609 } 2610 wlock_acquire(rtld_bind_lock, lockstate); 2611 unhold_object(elm->obj); 2612 /* No need to free anything if process is going down. */ 2613 if (root != NULL) 2614 free(elm); 2615 /* 2616 * We must restart the list traversal after every fini call 2617 * because a dlclose() call from the fini function or from 2618 * another thread might have modified the reference counts. 2619 */ 2620 break; 2621 } 2622 } while (elm != NULL); 2623 errmsg_restore(saved_msg); 2624 } 2625 2626 /* 2627 * Call the initialization functions for each of the objects in 2628 * "list". All of the objects are expected to have non-NULL init 2629 * functions. 2630 */ 2631 static void 2632 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2633 { 2634 Objlist_Entry *elm; 2635 Obj_Entry *obj; 2636 char *saved_msg; 2637 Elf_Addr *init_addr; 2638 int index; 2639 2640 /* 2641 * Clean init_scanned flag so that objects can be rechecked and 2642 * possibly initialized earlier if any of vectors called below 2643 * cause the change by using dlopen. 2644 */ 2645 TAILQ_FOREACH(obj, &obj_list, next) { 2646 if (obj->marker) 2647 continue; 2648 obj->init_scanned = false; 2649 } 2650 2651 /* 2652 * Preserve the current error message since an init function might 2653 * call into the dynamic linker and overwrite it. 2654 */ 2655 saved_msg = errmsg_save(); 2656 STAILQ_FOREACH(elm, list, link) { 2657 if (elm->obj->init_done) /* Initialized early. */ 2658 continue; 2659 /* 2660 * Race: other thread might try to use this object before current 2661 * one completes the initialization. Not much can be done here 2662 * without better locking. 2663 */ 2664 elm->obj->init_done = true; 2665 hold_object(elm->obj); 2666 lock_release(rtld_bind_lock, lockstate); 2667 2668 /* 2669 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2670 * When this happens, DT_INIT is processed first. 2671 */ 2672 if (elm->obj->init != (Elf_Addr)NULL) { 2673 dbg("calling init function for %s at %p", elm->obj->path, 2674 (void *)elm->obj->init); 2675 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2676 0, 0, elm->obj->path); 2677 call_initfini_pointer(elm->obj, elm->obj->init); 2678 } 2679 init_addr = (Elf_Addr *)elm->obj->init_array; 2680 if (init_addr != NULL) { 2681 for (index = 0; index < elm->obj->init_array_num; index++) { 2682 if (init_addr[index] != 0 && init_addr[index] != 1) { 2683 dbg("calling init function for %s at %p", elm->obj->path, 2684 (void *)init_addr[index]); 2685 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2686 (void *)init_addr[index], 0, 0, elm->obj->path); 2687 call_init_pointer(elm->obj, init_addr[index]); 2688 } 2689 } 2690 } 2691 wlock_acquire(rtld_bind_lock, lockstate); 2692 unhold_object(elm->obj); 2693 } 2694 errmsg_restore(saved_msg); 2695 } 2696 2697 static void 2698 objlist_clear(Objlist *list) 2699 { 2700 Objlist_Entry *elm; 2701 2702 while (!STAILQ_EMPTY(list)) { 2703 elm = STAILQ_FIRST(list); 2704 STAILQ_REMOVE_HEAD(list, link); 2705 free(elm); 2706 } 2707 } 2708 2709 static Objlist_Entry * 2710 objlist_find(Objlist *list, const Obj_Entry *obj) 2711 { 2712 Objlist_Entry *elm; 2713 2714 STAILQ_FOREACH(elm, list, link) 2715 if (elm->obj == obj) 2716 return elm; 2717 return NULL; 2718 } 2719 2720 static void 2721 objlist_init(Objlist *list) 2722 { 2723 STAILQ_INIT(list); 2724 } 2725 2726 static void 2727 objlist_push_head(Objlist *list, Obj_Entry *obj) 2728 { 2729 Objlist_Entry *elm; 2730 2731 elm = NEW(Objlist_Entry); 2732 elm->obj = obj; 2733 STAILQ_INSERT_HEAD(list, elm, link); 2734 } 2735 2736 static void 2737 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2738 { 2739 Objlist_Entry *elm; 2740 2741 elm = NEW(Objlist_Entry); 2742 elm->obj = obj; 2743 STAILQ_INSERT_TAIL(list, elm, link); 2744 } 2745 2746 static void 2747 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2748 { 2749 Objlist_Entry *elm, *listelm; 2750 2751 STAILQ_FOREACH(listelm, list, link) { 2752 if (listelm->obj == listobj) 2753 break; 2754 } 2755 elm = NEW(Objlist_Entry); 2756 elm->obj = obj; 2757 if (listelm != NULL) 2758 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2759 else 2760 STAILQ_INSERT_TAIL(list, elm, link); 2761 } 2762 2763 static void 2764 objlist_remove(Objlist *list, Obj_Entry *obj) 2765 { 2766 Objlist_Entry *elm; 2767 2768 if ((elm = objlist_find(list, obj)) != NULL) { 2769 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2770 free(elm); 2771 } 2772 } 2773 2774 /* 2775 * Relocate dag rooted in the specified object. 2776 * Returns 0 on success, or -1 on failure. 2777 */ 2778 2779 static int 2780 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2781 int flags, RtldLockState *lockstate) 2782 { 2783 Objlist_Entry *elm; 2784 int error; 2785 2786 error = 0; 2787 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2788 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2789 lockstate); 2790 if (error == -1) 2791 break; 2792 } 2793 return (error); 2794 } 2795 2796 /* 2797 * Prepare for, or clean after, relocating an object marked with 2798 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2799 * segments are remapped read-write. After relocations are done, the 2800 * segment's permissions are returned back to the modes specified in 2801 * the phdrs. If any relocation happened, or always for wired 2802 * program, COW is triggered. 2803 */ 2804 static int 2805 reloc_textrel_prot(Obj_Entry *obj, bool before) 2806 { 2807 const Elf_Phdr *ph; 2808 void *base; 2809 size_t l, sz; 2810 int prot; 2811 2812 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2813 l--, ph++) { 2814 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2815 continue; 2816 base = obj->relocbase + trunc_page(ph->p_vaddr); 2817 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2818 trunc_page(ph->p_vaddr); 2819 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2820 if (mprotect(base, sz, prot) == -1) { 2821 _rtld_error("%s: Cannot write-%sable text segment: %s", 2822 obj->path, before ? "en" : "dis", 2823 rtld_strerror(errno)); 2824 return (-1); 2825 } 2826 } 2827 return (0); 2828 } 2829 2830 /* 2831 * Relocate single object. 2832 * Returns 0 on success, or -1 on failure. 2833 */ 2834 static int 2835 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2836 int flags, RtldLockState *lockstate) 2837 { 2838 2839 if (obj->relocated) 2840 return (0); 2841 obj->relocated = true; 2842 if (obj != rtldobj) 2843 dbg("relocating \"%s\"", obj->path); 2844 2845 if (obj->symtab == NULL || obj->strtab == NULL || 2846 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2847 _rtld_error("%s: Shared object has no run-time symbol table", 2848 obj->path); 2849 return (-1); 2850 } 2851 2852 /* There are relocations to the write-protected text segment. */ 2853 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2854 return (-1); 2855 2856 /* Process the non-PLT non-IFUNC relocations. */ 2857 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2858 return (-1); 2859 2860 /* Re-protected the text segment. */ 2861 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2862 return (-1); 2863 2864 /* Set the special PLT or GOT entries. */ 2865 init_pltgot(obj); 2866 2867 /* Process the PLT relocations. */ 2868 if (reloc_plt(obj) == -1) 2869 return (-1); 2870 /* Relocate the jump slots if we are doing immediate binding. */ 2871 if (obj->bind_now || bind_now) { 2872 if (reloc_jmpslots(obj, flags, lockstate) == -1 || 2873 resolve_object_ifunc(obj, true, flags, lockstate) == -1) 2874 return (-1); 2875 } 2876 2877 /* 2878 * Process the non-PLT IFUNC relocations. The relocations are 2879 * processed in two phases, because IFUNC resolvers may 2880 * reference other symbols, which must be readily processed 2881 * before resolvers are called. 2882 */ 2883 if (obj->non_plt_gnu_ifunc && 2884 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2885 return (-1); 2886 2887 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2888 return (-1); 2889 2890 /* 2891 * Set up the magic number and version in the Obj_Entry. These 2892 * were checked in the crt1.o from the original ElfKit, so we 2893 * set them for backward compatibility. 2894 */ 2895 obj->magic = RTLD_MAGIC; 2896 obj->version = RTLD_VERSION; 2897 2898 return (0); 2899 } 2900 2901 /* 2902 * Relocate newly-loaded shared objects. The argument is a pointer to 2903 * the Obj_Entry for the first such object. All objects from the first 2904 * to the end of the list of objects are relocated. Returns 0 on success, 2905 * or -1 on failure. 2906 */ 2907 static int 2908 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2909 int flags, RtldLockState *lockstate) 2910 { 2911 Obj_Entry *obj; 2912 int error; 2913 2914 for (error = 0, obj = first; obj != NULL; 2915 obj = TAILQ_NEXT(obj, next)) { 2916 if (obj->marker) 2917 continue; 2918 error = relocate_object(obj, bind_now, rtldobj, flags, 2919 lockstate); 2920 if (error == -1) 2921 break; 2922 } 2923 return (error); 2924 } 2925 2926 /* 2927 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2928 * referencing STT_GNU_IFUNC symbols is postponed till the other 2929 * relocations are done. The indirect functions specified as 2930 * ifunc are allowed to call other symbols, so we need to have 2931 * objects relocated before asking for resolution from indirects. 2932 * 2933 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2934 * instead of the usual lazy handling of PLT slots. It is 2935 * consistent with how GNU does it. 2936 */ 2937 static int 2938 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2939 RtldLockState *lockstate) 2940 { 2941 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2942 return (-1); 2943 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2944 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2945 return (-1); 2946 return (0); 2947 } 2948 2949 static int 2950 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2951 RtldLockState *lockstate) 2952 { 2953 Obj_Entry *obj; 2954 2955 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2956 if (obj->marker) 2957 continue; 2958 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2959 return (-1); 2960 } 2961 return (0); 2962 } 2963 2964 static int 2965 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2966 RtldLockState *lockstate) 2967 { 2968 Objlist_Entry *elm; 2969 2970 STAILQ_FOREACH(elm, list, link) { 2971 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2972 lockstate) == -1) 2973 return (-1); 2974 } 2975 return (0); 2976 } 2977 2978 /* 2979 * Cleanup procedure. It will be called (by the atexit mechanism) just 2980 * before the process exits. 2981 */ 2982 static void 2983 rtld_exit(void) 2984 { 2985 RtldLockState lockstate; 2986 2987 wlock_acquire(rtld_bind_lock, &lockstate); 2988 dbg("rtld_exit()"); 2989 objlist_call_fini(&list_fini, NULL, &lockstate); 2990 /* No need to remove the items from the list, since we are exiting. */ 2991 if (!libmap_disable) 2992 lm_fini(); 2993 lock_release(rtld_bind_lock, &lockstate); 2994 } 2995 2996 /* 2997 * Iterate over a search path, translate each element, and invoke the 2998 * callback on the result. 2999 */ 3000 static void * 3001 path_enumerate(const char *path, path_enum_proc callback, 3002 const char *refobj_path, void *arg) 3003 { 3004 const char *trans; 3005 if (path == NULL) 3006 return (NULL); 3007 3008 path += strspn(path, ":;"); 3009 while (*path != '\0') { 3010 size_t len; 3011 char *res; 3012 3013 len = strcspn(path, ":;"); 3014 trans = lm_findn(refobj_path, path, len); 3015 if (trans) 3016 res = callback(trans, strlen(trans), arg); 3017 else 3018 res = callback(path, len, arg); 3019 3020 if (res != NULL) 3021 return (res); 3022 3023 path += len; 3024 path += strspn(path, ":;"); 3025 } 3026 3027 return (NULL); 3028 } 3029 3030 struct try_library_args { 3031 const char *name; 3032 size_t namelen; 3033 char *buffer; 3034 size_t buflen; 3035 int fd; 3036 }; 3037 3038 static void * 3039 try_library_path(const char *dir, size_t dirlen, void *param) 3040 { 3041 struct try_library_args *arg; 3042 int fd; 3043 3044 arg = param; 3045 if (*dir == '/' || trust) { 3046 char *pathname; 3047 3048 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3049 return (NULL); 3050 3051 pathname = arg->buffer; 3052 strncpy(pathname, dir, dirlen); 3053 pathname[dirlen] = '/'; 3054 strcpy(pathname + dirlen + 1, arg->name); 3055 3056 dbg(" Trying \"%s\"", pathname); 3057 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3058 if (fd >= 0) { 3059 dbg(" Opened \"%s\", fd %d", pathname, fd); 3060 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3061 strcpy(pathname, arg->buffer); 3062 arg->fd = fd; 3063 return (pathname); 3064 } else { 3065 dbg(" Failed to open \"%s\": %s", 3066 pathname, rtld_strerror(errno)); 3067 } 3068 } 3069 return (NULL); 3070 } 3071 3072 static char * 3073 search_library_path(const char *name, const char *path, 3074 const char *refobj_path, int *fdp) 3075 { 3076 char *p; 3077 struct try_library_args arg; 3078 3079 if (path == NULL) 3080 return NULL; 3081 3082 arg.name = name; 3083 arg.namelen = strlen(name); 3084 arg.buffer = xmalloc(PATH_MAX); 3085 arg.buflen = PATH_MAX; 3086 arg.fd = -1; 3087 3088 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3089 *fdp = arg.fd; 3090 3091 free(arg.buffer); 3092 3093 return (p); 3094 } 3095 3096 3097 /* 3098 * Finds the library with the given name using the directory descriptors 3099 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3100 * 3101 * Returns a freshly-opened close-on-exec file descriptor for the library, 3102 * or -1 if the library cannot be found. 3103 */ 3104 static char * 3105 search_library_pathfds(const char *name, const char *path, int *fdp) 3106 { 3107 char *envcopy, *fdstr, *found, *last_token; 3108 size_t len; 3109 int dirfd, fd; 3110 3111 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3112 3113 /* Don't load from user-specified libdirs into setuid binaries. */ 3114 if (!trust) 3115 return (NULL); 3116 3117 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3118 if (path == NULL) 3119 return (NULL); 3120 3121 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3122 if (name[0] == '/') { 3123 dbg("Absolute path (%s) passed to %s", name, __func__); 3124 return (NULL); 3125 } 3126 3127 /* 3128 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3129 * copy of the path, as strtok_r rewrites separator tokens 3130 * with '\0'. 3131 */ 3132 found = NULL; 3133 envcopy = xstrdup(path); 3134 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3135 fdstr = strtok_r(NULL, ":", &last_token)) { 3136 dirfd = parse_integer(fdstr); 3137 if (dirfd < 0) { 3138 _rtld_error("failed to parse directory FD: '%s'", 3139 fdstr); 3140 break; 3141 } 3142 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3143 if (fd >= 0) { 3144 *fdp = fd; 3145 len = strlen(fdstr) + strlen(name) + 3; 3146 found = xmalloc(len); 3147 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3148 _rtld_error("error generating '%d/%s'", 3149 dirfd, name); 3150 rtld_die(); 3151 } 3152 dbg("open('%s') => %d", found, fd); 3153 break; 3154 } 3155 } 3156 free(envcopy); 3157 3158 return (found); 3159 } 3160 3161 3162 int 3163 dlclose(void *handle) 3164 { 3165 RtldLockState lockstate; 3166 int error; 3167 3168 wlock_acquire(rtld_bind_lock, &lockstate); 3169 error = dlclose_locked(handle, &lockstate); 3170 lock_release(rtld_bind_lock, &lockstate); 3171 return (error); 3172 } 3173 3174 static int 3175 dlclose_locked(void *handle, RtldLockState *lockstate) 3176 { 3177 Obj_Entry *root; 3178 3179 root = dlcheck(handle); 3180 if (root == NULL) 3181 return -1; 3182 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3183 root->path); 3184 3185 /* Unreference the object and its dependencies. */ 3186 root->dl_refcount--; 3187 3188 if (root->refcount == 1) { 3189 /* 3190 * The object will be no longer referenced, so we must unload it. 3191 * First, call the fini functions. 3192 */ 3193 objlist_call_fini(&list_fini, root, lockstate); 3194 3195 unref_dag(root); 3196 3197 /* Finish cleaning up the newly-unreferenced objects. */ 3198 GDB_STATE(RT_DELETE,&root->linkmap); 3199 unload_object(root, lockstate); 3200 GDB_STATE(RT_CONSISTENT,NULL); 3201 } else 3202 unref_dag(root); 3203 3204 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3205 return 0; 3206 } 3207 3208 char * 3209 dlerror(void) 3210 { 3211 char *msg = error_message; 3212 error_message = NULL; 3213 return msg; 3214 } 3215 3216 /* 3217 * This function is deprecated and has no effect. 3218 */ 3219 void 3220 dllockinit(void *context, 3221 void *(*lock_create)(void *context), 3222 void (*rlock_acquire)(void *lock), 3223 void (*wlock_acquire)(void *lock), 3224 void (*lock_release)(void *lock), 3225 void (*lock_destroy)(void *lock), 3226 void (*context_destroy)(void *context)) 3227 { 3228 static void *cur_context; 3229 static void (*cur_context_destroy)(void *); 3230 3231 /* Just destroy the context from the previous call, if necessary. */ 3232 if (cur_context_destroy != NULL) 3233 cur_context_destroy(cur_context); 3234 cur_context = context; 3235 cur_context_destroy = context_destroy; 3236 } 3237 3238 void * 3239 dlopen(const char *name, int mode) 3240 { 3241 3242 return (rtld_dlopen(name, -1, mode)); 3243 } 3244 3245 void * 3246 fdlopen(int fd, int mode) 3247 { 3248 3249 return (rtld_dlopen(NULL, fd, mode)); 3250 } 3251 3252 static void * 3253 rtld_dlopen(const char *name, int fd, int mode) 3254 { 3255 RtldLockState lockstate; 3256 int lo_flags; 3257 3258 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3259 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3260 if (ld_tracing != NULL) { 3261 rlock_acquire(rtld_bind_lock, &lockstate); 3262 if (sigsetjmp(lockstate.env, 0) != 0) 3263 lock_upgrade(rtld_bind_lock, &lockstate); 3264 environ = (char **)*get_program_var_addr("environ", &lockstate); 3265 lock_release(rtld_bind_lock, &lockstate); 3266 } 3267 lo_flags = RTLD_LO_DLOPEN; 3268 if (mode & RTLD_NODELETE) 3269 lo_flags |= RTLD_LO_NODELETE; 3270 if (mode & RTLD_NOLOAD) 3271 lo_flags |= RTLD_LO_NOLOAD; 3272 if (ld_tracing != NULL) 3273 lo_flags |= RTLD_LO_TRACE; 3274 3275 return (dlopen_object(name, fd, obj_main, lo_flags, 3276 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3277 } 3278 3279 static void 3280 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3281 { 3282 3283 obj->dl_refcount--; 3284 unref_dag(obj); 3285 if (obj->refcount == 0) 3286 unload_object(obj, lockstate); 3287 } 3288 3289 static Obj_Entry * 3290 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3291 int mode, RtldLockState *lockstate) 3292 { 3293 Obj_Entry *old_obj_tail; 3294 Obj_Entry *obj; 3295 Objlist initlist; 3296 RtldLockState mlockstate; 3297 int result; 3298 3299 objlist_init(&initlist); 3300 3301 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3302 wlock_acquire(rtld_bind_lock, &mlockstate); 3303 lockstate = &mlockstate; 3304 } 3305 GDB_STATE(RT_ADD,NULL); 3306 3307 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3308 obj = NULL; 3309 if (name == NULL && fd == -1) { 3310 obj = obj_main; 3311 obj->refcount++; 3312 } else { 3313 obj = load_object(name, fd, refobj, lo_flags); 3314 } 3315 3316 if (obj) { 3317 obj->dl_refcount++; 3318 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3319 objlist_push_tail(&list_global, obj); 3320 if (globallist_next(old_obj_tail) != NULL) { 3321 /* We loaded something new. */ 3322 assert(globallist_next(old_obj_tail) == obj); 3323 result = load_needed_objects(obj, 3324 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3325 init_dag(obj); 3326 ref_dag(obj); 3327 if (result != -1) 3328 result = rtld_verify_versions(&obj->dagmembers); 3329 if (result != -1 && ld_tracing) 3330 goto trace; 3331 if (result == -1 || relocate_object_dag(obj, 3332 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3333 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3334 lockstate) == -1) { 3335 dlopen_cleanup(obj, lockstate); 3336 obj = NULL; 3337 } else if (lo_flags & RTLD_LO_EARLY) { 3338 /* 3339 * Do not call the init functions for early loaded 3340 * filtees. The image is still not initialized enough 3341 * for them to work. 3342 * 3343 * Our object is found by the global object list and 3344 * will be ordered among all init calls done right 3345 * before transferring control to main. 3346 */ 3347 } else { 3348 /* Make list of init functions to call. */ 3349 initlist_add_objects(obj, obj, &initlist); 3350 } 3351 /* 3352 * Process all no_delete or global objects here, given 3353 * them own DAGs to prevent their dependencies from being 3354 * unloaded. This has to be done after we have loaded all 3355 * of the dependencies, so that we do not miss any. 3356 */ 3357 if (obj != NULL) 3358 process_z(obj); 3359 } else { 3360 /* 3361 * Bump the reference counts for objects on this DAG. If 3362 * this is the first dlopen() call for the object that was 3363 * already loaded as a dependency, initialize the dag 3364 * starting at it. 3365 */ 3366 init_dag(obj); 3367 ref_dag(obj); 3368 3369 if ((lo_flags & RTLD_LO_TRACE) != 0) 3370 goto trace; 3371 } 3372 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3373 obj->z_nodelete) && !obj->ref_nodel) { 3374 dbg("obj %s nodelete", obj->path); 3375 ref_dag(obj); 3376 obj->z_nodelete = obj->ref_nodel = true; 3377 } 3378 } 3379 3380 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3381 name); 3382 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3383 3384 if (!(lo_flags & RTLD_LO_EARLY)) { 3385 map_stacks_exec(lockstate); 3386 } 3387 3388 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3389 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3390 lockstate) == -1) { 3391 objlist_clear(&initlist); 3392 dlopen_cleanup(obj, lockstate); 3393 if (lockstate == &mlockstate) 3394 lock_release(rtld_bind_lock, lockstate); 3395 return (NULL); 3396 } 3397 3398 if (!(lo_flags & RTLD_LO_EARLY)) { 3399 /* Call the init functions. */ 3400 objlist_call_init(&initlist, lockstate); 3401 } 3402 objlist_clear(&initlist); 3403 if (lockstate == &mlockstate) 3404 lock_release(rtld_bind_lock, lockstate); 3405 return obj; 3406 trace: 3407 trace_loaded_objects(obj); 3408 if (lockstate == &mlockstate) 3409 lock_release(rtld_bind_lock, lockstate); 3410 exit(0); 3411 } 3412 3413 static void * 3414 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3415 int flags) 3416 { 3417 DoneList donelist; 3418 const Obj_Entry *obj, *defobj; 3419 const Elf_Sym *def; 3420 SymLook req; 3421 RtldLockState lockstate; 3422 tls_index ti; 3423 void *sym; 3424 int res; 3425 3426 def = NULL; 3427 defobj = NULL; 3428 symlook_init(&req, name); 3429 req.ventry = ve; 3430 req.flags = flags | SYMLOOK_IN_PLT; 3431 req.lockstate = &lockstate; 3432 3433 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3434 rlock_acquire(rtld_bind_lock, &lockstate); 3435 if (sigsetjmp(lockstate.env, 0) != 0) 3436 lock_upgrade(rtld_bind_lock, &lockstate); 3437 if (handle == NULL || handle == RTLD_NEXT || 3438 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3439 3440 if ((obj = obj_from_addr(retaddr)) == NULL) { 3441 _rtld_error("Cannot determine caller's shared object"); 3442 lock_release(rtld_bind_lock, &lockstate); 3443 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3444 return NULL; 3445 } 3446 if (handle == NULL) { /* Just the caller's shared object. */ 3447 res = symlook_obj(&req, obj); 3448 if (res == 0) { 3449 def = req.sym_out; 3450 defobj = req.defobj_out; 3451 } 3452 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3453 handle == RTLD_SELF) { /* ... caller included */ 3454 if (handle == RTLD_NEXT) 3455 obj = globallist_next(obj); 3456 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3457 if (obj->marker) 3458 continue; 3459 res = symlook_obj(&req, obj); 3460 if (res == 0) { 3461 if (def == NULL || 3462 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3463 def = req.sym_out; 3464 defobj = req.defobj_out; 3465 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3466 break; 3467 } 3468 } 3469 } 3470 /* 3471 * Search the dynamic linker itself, and possibly resolve the 3472 * symbol from there. This is how the application links to 3473 * dynamic linker services such as dlopen. 3474 */ 3475 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3476 res = symlook_obj(&req, &obj_rtld); 3477 if (res == 0) { 3478 def = req.sym_out; 3479 defobj = req.defobj_out; 3480 } 3481 } 3482 } else { 3483 assert(handle == RTLD_DEFAULT); 3484 res = symlook_default(&req, obj); 3485 if (res == 0) { 3486 defobj = req.defobj_out; 3487 def = req.sym_out; 3488 } 3489 } 3490 } else { 3491 if ((obj = dlcheck(handle)) == NULL) { 3492 lock_release(rtld_bind_lock, &lockstate); 3493 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3494 return NULL; 3495 } 3496 3497 donelist_init(&donelist); 3498 if (obj->mainprog) { 3499 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3500 res = symlook_global(&req, &donelist); 3501 if (res == 0) { 3502 def = req.sym_out; 3503 defobj = req.defobj_out; 3504 } 3505 /* 3506 * Search the dynamic linker itself, and possibly resolve the 3507 * symbol from there. This is how the application links to 3508 * dynamic linker services such as dlopen. 3509 */ 3510 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3511 res = symlook_obj(&req, &obj_rtld); 3512 if (res == 0) { 3513 def = req.sym_out; 3514 defobj = req.defobj_out; 3515 } 3516 } 3517 } 3518 else { 3519 /* Search the whole DAG rooted at the given object. */ 3520 res = symlook_list(&req, &obj->dagmembers, &donelist); 3521 if (res == 0) { 3522 def = req.sym_out; 3523 defobj = req.defobj_out; 3524 } 3525 } 3526 } 3527 3528 if (def != NULL) { 3529 lock_release(rtld_bind_lock, &lockstate); 3530 3531 /* 3532 * The value required by the caller is derived from the value 3533 * of the symbol. this is simply the relocated value of the 3534 * symbol. 3535 */ 3536 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3537 sym = make_function_pointer(def, defobj); 3538 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3539 sym = rtld_resolve_ifunc(defobj, def); 3540 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3541 ti.ti_module = defobj->tlsindex; 3542 ti.ti_offset = def->st_value; 3543 sym = __tls_get_addr(&ti); 3544 } else 3545 sym = defobj->relocbase + def->st_value; 3546 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3547 return (sym); 3548 } 3549 3550 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3551 ve != NULL ? ve->name : ""); 3552 lock_release(rtld_bind_lock, &lockstate); 3553 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3554 return NULL; 3555 } 3556 3557 void * 3558 dlsym(void *handle, const char *name) 3559 { 3560 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3561 SYMLOOK_DLSYM); 3562 } 3563 3564 dlfunc_t 3565 dlfunc(void *handle, const char *name) 3566 { 3567 union { 3568 void *d; 3569 dlfunc_t f; 3570 } rv; 3571 3572 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3573 SYMLOOK_DLSYM); 3574 return (rv.f); 3575 } 3576 3577 void * 3578 dlvsym(void *handle, const char *name, const char *version) 3579 { 3580 Ver_Entry ventry; 3581 3582 ventry.name = version; 3583 ventry.file = NULL; 3584 ventry.hash = elf_hash(version); 3585 ventry.flags= 0; 3586 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3587 SYMLOOK_DLSYM); 3588 } 3589 3590 int 3591 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3592 { 3593 const Obj_Entry *obj; 3594 RtldLockState lockstate; 3595 3596 rlock_acquire(rtld_bind_lock, &lockstate); 3597 obj = obj_from_addr(addr); 3598 if (obj == NULL) { 3599 _rtld_error("No shared object contains address"); 3600 lock_release(rtld_bind_lock, &lockstate); 3601 return (0); 3602 } 3603 rtld_fill_dl_phdr_info(obj, phdr_info); 3604 lock_release(rtld_bind_lock, &lockstate); 3605 return (1); 3606 } 3607 3608 int 3609 dladdr(const void *addr, Dl_info *info) 3610 { 3611 const Obj_Entry *obj; 3612 const Elf_Sym *def; 3613 void *symbol_addr; 3614 unsigned long symoffset; 3615 RtldLockState lockstate; 3616 3617 rlock_acquire(rtld_bind_lock, &lockstate); 3618 obj = obj_from_addr(addr); 3619 if (obj == NULL) { 3620 _rtld_error("No shared object contains address"); 3621 lock_release(rtld_bind_lock, &lockstate); 3622 return 0; 3623 } 3624 info->dli_fname = obj->path; 3625 info->dli_fbase = obj->mapbase; 3626 info->dli_saddr = (void *)0; 3627 info->dli_sname = NULL; 3628 3629 /* 3630 * Walk the symbol list looking for the symbol whose address is 3631 * closest to the address sent in. 3632 */ 3633 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3634 def = obj->symtab + symoffset; 3635 3636 /* 3637 * For skip the symbol if st_shndx is either SHN_UNDEF or 3638 * SHN_COMMON. 3639 */ 3640 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3641 continue; 3642 3643 /* 3644 * If the symbol is greater than the specified address, or if it 3645 * is further away from addr than the current nearest symbol, 3646 * then reject it. 3647 */ 3648 symbol_addr = obj->relocbase + def->st_value; 3649 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3650 continue; 3651 3652 /* Update our idea of the nearest symbol. */ 3653 info->dli_sname = obj->strtab + def->st_name; 3654 info->dli_saddr = symbol_addr; 3655 3656 /* Exact match? */ 3657 if (info->dli_saddr == addr) 3658 break; 3659 } 3660 lock_release(rtld_bind_lock, &lockstate); 3661 return 1; 3662 } 3663 3664 int 3665 dlinfo(void *handle, int request, void *p) 3666 { 3667 const Obj_Entry *obj; 3668 RtldLockState lockstate; 3669 int error; 3670 3671 rlock_acquire(rtld_bind_lock, &lockstate); 3672 3673 if (handle == NULL || handle == RTLD_SELF) { 3674 void *retaddr; 3675 3676 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3677 if ((obj = obj_from_addr(retaddr)) == NULL) 3678 _rtld_error("Cannot determine caller's shared object"); 3679 } else 3680 obj = dlcheck(handle); 3681 3682 if (obj == NULL) { 3683 lock_release(rtld_bind_lock, &lockstate); 3684 return (-1); 3685 } 3686 3687 error = 0; 3688 switch (request) { 3689 case RTLD_DI_LINKMAP: 3690 *((struct link_map const **)p) = &obj->linkmap; 3691 break; 3692 case RTLD_DI_ORIGIN: 3693 error = rtld_dirname(obj->path, p); 3694 break; 3695 3696 case RTLD_DI_SERINFOSIZE: 3697 case RTLD_DI_SERINFO: 3698 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3699 break; 3700 3701 default: 3702 _rtld_error("Invalid request %d passed to dlinfo()", request); 3703 error = -1; 3704 } 3705 3706 lock_release(rtld_bind_lock, &lockstate); 3707 3708 return (error); 3709 } 3710 3711 static void 3712 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3713 { 3714 3715 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3716 phdr_info->dlpi_name = obj->path; 3717 phdr_info->dlpi_phdr = obj->phdr; 3718 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3719 phdr_info->dlpi_tls_modid = obj->tlsindex; 3720 phdr_info->dlpi_tls_data = obj->tlsinit; 3721 phdr_info->dlpi_adds = obj_loads; 3722 phdr_info->dlpi_subs = obj_loads - obj_count; 3723 } 3724 3725 int 3726 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3727 { 3728 struct dl_phdr_info phdr_info; 3729 Obj_Entry *obj, marker; 3730 RtldLockState bind_lockstate, phdr_lockstate; 3731 int error; 3732 3733 init_marker(&marker); 3734 error = 0; 3735 3736 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3737 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3738 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3739 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3740 rtld_fill_dl_phdr_info(obj, &phdr_info); 3741 hold_object(obj); 3742 lock_release(rtld_bind_lock, &bind_lockstate); 3743 3744 error = callback(&phdr_info, sizeof phdr_info, param); 3745 3746 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3747 unhold_object(obj); 3748 obj = globallist_next(&marker); 3749 TAILQ_REMOVE(&obj_list, &marker, next); 3750 if (error != 0) { 3751 lock_release(rtld_bind_lock, &bind_lockstate); 3752 lock_release(rtld_phdr_lock, &phdr_lockstate); 3753 return (error); 3754 } 3755 } 3756 3757 if (error == 0) { 3758 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3759 lock_release(rtld_bind_lock, &bind_lockstate); 3760 error = callback(&phdr_info, sizeof(phdr_info), param); 3761 } 3762 lock_release(rtld_phdr_lock, &phdr_lockstate); 3763 return (error); 3764 } 3765 3766 static void * 3767 fill_search_info(const char *dir, size_t dirlen, void *param) 3768 { 3769 struct fill_search_info_args *arg; 3770 3771 arg = param; 3772 3773 if (arg->request == RTLD_DI_SERINFOSIZE) { 3774 arg->serinfo->dls_cnt ++; 3775 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3776 } else { 3777 struct dl_serpath *s_entry; 3778 3779 s_entry = arg->serpath; 3780 s_entry->dls_name = arg->strspace; 3781 s_entry->dls_flags = arg->flags; 3782 3783 strncpy(arg->strspace, dir, dirlen); 3784 arg->strspace[dirlen] = '\0'; 3785 3786 arg->strspace += dirlen + 1; 3787 arg->serpath++; 3788 } 3789 3790 return (NULL); 3791 } 3792 3793 static int 3794 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3795 { 3796 struct dl_serinfo _info; 3797 struct fill_search_info_args args; 3798 3799 args.request = RTLD_DI_SERINFOSIZE; 3800 args.serinfo = &_info; 3801 3802 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3803 _info.dls_cnt = 0; 3804 3805 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3806 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3807 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3808 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3809 if (!obj->z_nodeflib) 3810 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3811 3812 3813 if (request == RTLD_DI_SERINFOSIZE) { 3814 info->dls_size = _info.dls_size; 3815 info->dls_cnt = _info.dls_cnt; 3816 return (0); 3817 } 3818 3819 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3820 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3821 return (-1); 3822 } 3823 3824 args.request = RTLD_DI_SERINFO; 3825 args.serinfo = info; 3826 args.serpath = &info->dls_serpath[0]; 3827 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3828 3829 args.flags = LA_SER_RUNPATH; 3830 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3831 return (-1); 3832 3833 args.flags = LA_SER_LIBPATH; 3834 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3835 return (-1); 3836 3837 args.flags = LA_SER_RUNPATH; 3838 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3839 return (-1); 3840 3841 args.flags = LA_SER_CONFIG; 3842 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3843 != NULL) 3844 return (-1); 3845 3846 args.flags = LA_SER_DEFAULT; 3847 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3848 fill_search_info, NULL, &args) != NULL) 3849 return (-1); 3850 return (0); 3851 } 3852 3853 static int 3854 rtld_dirname(const char *path, char *bname) 3855 { 3856 const char *endp; 3857 3858 /* Empty or NULL string gets treated as "." */ 3859 if (path == NULL || *path == '\0') { 3860 bname[0] = '.'; 3861 bname[1] = '\0'; 3862 return (0); 3863 } 3864 3865 /* Strip trailing slashes */ 3866 endp = path + strlen(path) - 1; 3867 while (endp > path && *endp == '/') 3868 endp--; 3869 3870 /* Find the start of the dir */ 3871 while (endp > path && *endp != '/') 3872 endp--; 3873 3874 /* Either the dir is "/" or there are no slashes */ 3875 if (endp == path) { 3876 bname[0] = *endp == '/' ? '/' : '.'; 3877 bname[1] = '\0'; 3878 return (0); 3879 } else { 3880 do { 3881 endp--; 3882 } while (endp > path && *endp == '/'); 3883 } 3884 3885 if (endp - path + 2 > PATH_MAX) 3886 { 3887 _rtld_error("Filename is too long: %s", path); 3888 return(-1); 3889 } 3890 3891 strncpy(bname, path, endp - path + 1); 3892 bname[endp - path + 1] = '\0'; 3893 return (0); 3894 } 3895 3896 static int 3897 rtld_dirname_abs(const char *path, char *base) 3898 { 3899 char *last; 3900 3901 if (realpath(path, base) == NULL) 3902 return (-1); 3903 dbg("%s -> %s", path, base); 3904 last = strrchr(base, '/'); 3905 if (last == NULL) 3906 return (-1); 3907 if (last != base) 3908 *last = '\0'; 3909 return (0); 3910 } 3911 3912 static void 3913 linkmap_add(Obj_Entry *obj) 3914 { 3915 struct link_map *l = &obj->linkmap; 3916 struct link_map *prev; 3917 3918 obj->linkmap.l_name = obj->path; 3919 obj->linkmap.l_addr = obj->mapbase; 3920 obj->linkmap.l_ld = obj->dynamic; 3921 #ifdef __mips__ 3922 /* GDB needs load offset on MIPS to use the symbols */ 3923 obj->linkmap.l_offs = obj->relocbase; 3924 #endif 3925 3926 if (r_debug.r_map == NULL) { 3927 r_debug.r_map = l; 3928 return; 3929 } 3930 3931 /* 3932 * Scan to the end of the list, but not past the entry for the 3933 * dynamic linker, which we want to keep at the very end. 3934 */ 3935 for (prev = r_debug.r_map; 3936 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3937 prev = prev->l_next) 3938 ; 3939 3940 /* Link in the new entry. */ 3941 l->l_prev = prev; 3942 l->l_next = prev->l_next; 3943 if (l->l_next != NULL) 3944 l->l_next->l_prev = l; 3945 prev->l_next = l; 3946 } 3947 3948 static void 3949 linkmap_delete(Obj_Entry *obj) 3950 { 3951 struct link_map *l = &obj->linkmap; 3952 3953 if (l->l_prev == NULL) { 3954 if ((r_debug.r_map = l->l_next) != NULL) 3955 l->l_next->l_prev = NULL; 3956 return; 3957 } 3958 3959 if ((l->l_prev->l_next = l->l_next) != NULL) 3960 l->l_next->l_prev = l->l_prev; 3961 } 3962 3963 /* 3964 * Function for the debugger to set a breakpoint on to gain control. 3965 * 3966 * The two parameters allow the debugger to easily find and determine 3967 * what the runtime loader is doing and to whom it is doing it. 3968 * 3969 * When the loadhook trap is hit (r_debug_state, set at program 3970 * initialization), the arguments can be found on the stack: 3971 * 3972 * +8 struct link_map *m 3973 * +4 struct r_debug *rd 3974 * +0 RetAddr 3975 */ 3976 void 3977 r_debug_state(struct r_debug* rd, struct link_map *m) 3978 { 3979 /* 3980 * The following is a hack to force the compiler to emit calls to 3981 * this function, even when optimizing. If the function is empty, 3982 * the compiler is not obliged to emit any code for calls to it, 3983 * even when marked __noinline. However, gdb depends on those 3984 * calls being made. 3985 */ 3986 __compiler_membar(); 3987 } 3988 3989 /* 3990 * A function called after init routines have completed. This can be used to 3991 * break before a program's entry routine is called, and can be used when 3992 * main is not available in the symbol table. 3993 */ 3994 void 3995 _r_debug_postinit(struct link_map *m) 3996 { 3997 3998 /* See r_debug_state(). */ 3999 __compiler_membar(); 4000 } 4001 4002 static void 4003 release_object(Obj_Entry *obj) 4004 { 4005 4006 if (obj->holdcount > 0) { 4007 obj->unholdfree = true; 4008 return; 4009 } 4010 munmap(obj->mapbase, obj->mapsize); 4011 linkmap_delete(obj); 4012 obj_free(obj); 4013 } 4014 4015 /* 4016 * Get address of the pointer variable in the main program. 4017 * Prefer non-weak symbol over the weak one. 4018 */ 4019 static const void ** 4020 get_program_var_addr(const char *name, RtldLockState *lockstate) 4021 { 4022 SymLook req; 4023 DoneList donelist; 4024 4025 symlook_init(&req, name); 4026 req.lockstate = lockstate; 4027 donelist_init(&donelist); 4028 if (symlook_global(&req, &donelist) != 0) 4029 return (NULL); 4030 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4031 return ((const void **)make_function_pointer(req.sym_out, 4032 req.defobj_out)); 4033 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4034 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4035 else 4036 return ((const void **)(req.defobj_out->relocbase + 4037 req.sym_out->st_value)); 4038 } 4039 4040 /* 4041 * Set a pointer variable in the main program to the given value. This 4042 * is used to set key variables such as "environ" before any of the 4043 * init functions are called. 4044 */ 4045 static void 4046 set_program_var(const char *name, const void *value) 4047 { 4048 const void **addr; 4049 4050 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4051 dbg("\"%s\": *%p <-- %p", name, addr, value); 4052 *addr = value; 4053 } 4054 } 4055 4056 /* 4057 * Search the global objects, including dependencies and main object, 4058 * for the given symbol. 4059 */ 4060 static int 4061 symlook_global(SymLook *req, DoneList *donelist) 4062 { 4063 SymLook req1; 4064 const Objlist_Entry *elm; 4065 int res; 4066 4067 symlook_init_from_req(&req1, req); 4068 4069 /* Search all objects loaded at program start up. */ 4070 if (req->defobj_out == NULL || 4071 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4072 res = symlook_list(&req1, &list_main, donelist); 4073 if (res == 0 && (req->defobj_out == NULL || 4074 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4075 req->sym_out = req1.sym_out; 4076 req->defobj_out = req1.defobj_out; 4077 assert(req->defobj_out != NULL); 4078 } 4079 } 4080 4081 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4082 STAILQ_FOREACH(elm, &list_global, link) { 4083 if (req->defobj_out != NULL && 4084 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4085 break; 4086 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4087 if (res == 0 && (req->defobj_out == NULL || 4088 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4089 req->sym_out = req1.sym_out; 4090 req->defobj_out = req1.defobj_out; 4091 assert(req->defobj_out != NULL); 4092 } 4093 } 4094 4095 return (req->sym_out != NULL ? 0 : ESRCH); 4096 } 4097 4098 /* 4099 * Given a symbol name in a referencing object, find the corresponding 4100 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4101 * no definition was found. Returns a pointer to the Obj_Entry of the 4102 * defining object via the reference parameter DEFOBJ_OUT. 4103 */ 4104 static int 4105 symlook_default(SymLook *req, const Obj_Entry *refobj) 4106 { 4107 DoneList donelist; 4108 const Objlist_Entry *elm; 4109 SymLook req1; 4110 int res; 4111 4112 donelist_init(&donelist); 4113 symlook_init_from_req(&req1, req); 4114 4115 /* 4116 * Look first in the referencing object if linked symbolically, 4117 * and similarly handle protected symbols. 4118 */ 4119 res = symlook_obj(&req1, refobj); 4120 if (res == 0 && (refobj->symbolic || 4121 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4122 req->sym_out = req1.sym_out; 4123 req->defobj_out = req1.defobj_out; 4124 assert(req->defobj_out != NULL); 4125 } 4126 if (refobj->symbolic || req->defobj_out != NULL) 4127 donelist_check(&donelist, refobj); 4128 4129 symlook_global(req, &donelist); 4130 4131 /* Search all dlopened DAGs containing the referencing object. */ 4132 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4133 if (req->sym_out != NULL && 4134 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4135 break; 4136 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4137 if (res == 0 && (req->sym_out == NULL || 4138 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4139 req->sym_out = req1.sym_out; 4140 req->defobj_out = req1.defobj_out; 4141 assert(req->defobj_out != NULL); 4142 } 4143 } 4144 4145 /* 4146 * Search the dynamic linker itself, and possibly resolve the 4147 * symbol from there. This is how the application links to 4148 * dynamic linker services such as dlopen. 4149 */ 4150 if (req->sym_out == NULL || 4151 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4152 res = symlook_obj(&req1, &obj_rtld); 4153 if (res == 0) { 4154 req->sym_out = req1.sym_out; 4155 req->defobj_out = req1.defobj_out; 4156 assert(req->defobj_out != NULL); 4157 } 4158 } 4159 4160 return (req->sym_out != NULL ? 0 : ESRCH); 4161 } 4162 4163 static int 4164 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4165 { 4166 const Elf_Sym *def; 4167 const Obj_Entry *defobj; 4168 const Objlist_Entry *elm; 4169 SymLook req1; 4170 int res; 4171 4172 def = NULL; 4173 defobj = NULL; 4174 STAILQ_FOREACH(elm, objlist, link) { 4175 if (donelist_check(dlp, elm->obj)) 4176 continue; 4177 symlook_init_from_req(&req1, req); 4178 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4179 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4180 def = req1.sym_out; 4181 defobj = req1.defobj_out; 4182 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4183 break; 4184 } 4185 } 4186 } 4187 if (def != NULL) { 4188 req->sym_out = def; 4189 req->defobj_out = defobj; 4190 return (0); 4191 } 4192 return (ESRCH); 4193 } 4194 4195 /* 4196 * Search the chain of DAGS cointed to by the given Needed_Entry 4197 * for a symbol of the given name. Each DAG is scanned completely 4198 * before advancing to the next one. Returns a pointer to the symbol, 4199 * or NULL if no definition was found. 4200 */ 4201 static int 4202 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4203 { 4204 const Elf_Sym *def; 4205 const Needed_Entry *n; 4206 const Obj_Entry *defobj; 4207 SymLook req1; 4208 int res; 4209 4210 def = NULL; 4211 defobj = NULL; 4212 symlook_init_from_req(&req1, req); 4213 for (n = needed; n != NULL; n = n->next) { 4214 if (n->obj == NULL || 4215 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4216 continue; 4217 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4218 def = req1.sym_out; 4219 defobj = req1.defobj_out; 4220 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4221 break; 4222 } 4223 } 4224 if (def != NULL) { 4225 req->sym_out = def; 4226 req->defobj_out = defobj; 4227 return (0); 4228 } 4229 return (ESRCH); 4230 } 4231 4232 /* 4233 * Search the symbol table of a single shared object for a symbol of 4234 * the given name and version, if requested. Returns a pointer to the 4235 * symbol, or NULL if no definition was found. If the object is 4236 * filter, return filtered symbol from filtee. 4237 * 4238 * The symbol's hash value is passed in for efficiency reasons; that 4239 * eliminates many recomputations of the hash value. 4240 */ 4241 int 4242 symlook_obj(SymLook *req, const Obj_Entry *obj) 4243 { 4244 DoneList donelist; 4245 SymLook req1; 4246 int flags, res, mres; 4247 4248 /* 4249 * If there is at least one valid hash at this point, we prefer to 4250 * use the faster GNU version if available. 4251 */ 4252 if (obj->valid_hash_gnu) 4253 mres = symlook_obj1_gnu(req, obj); 4254 else if (obj->valid_hash_sysv) 4255 mres = symlook_obj1_sysv(req, obj); 4256 else 4257 return (EINVAL); 4258 4259 if (mres == 0) { 4260 if (obj->needed_filtees != NULL) { 4261 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4262 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4263 donelist_init(&donelist); 4264 symlook_init_from_req(&req1, req); 4265 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4266 if (res == 0) { 4267 req->sym_out = req1.sym_out; 4268 req->defobj_out = req1.defobj_out; 4269 } 4270 return (res); 4271 } 4272 if (obj->needed_aux_filtees != NULL) { 4273 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4274 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4275 donelist_init(&donelist); 4276 symlook_init_from_req(&req1, req); 4277 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4278 if (res == 0) { 4279 req->sym_out = req1.sym_out; 4280 req->defobj_out = req1.defobj_out; 4281 return (res); 4282 } 4283 } 4284 } 4285 return (mres); 4286 } 4287 4288 /* Symbol match routine common to both hash functions */ 4289 static bool 4290 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4291 const unsigned long symnum) 4292 { 4293 Elf_Versym verndx; 4294 const Elf_Sym *symp; 4295 const char *strp; 4296 4297 symp = obj->symtab + symnum; 4298 strp = obj->strtab + symp->st_name; 4299 4300 switch (ELF_ST_TYPE(symp->st_info)) { 4301 case STT_FUNC: 4302 case STT_NOTYPE: 4303 case STT_OBJECT: 4304 case STT_COMMON: 4305 case STT_GNU_IFUNC: 4306 if (symp->st_value == 0) 4307 return (false); 4308 /* fallthrough */ 4309 case STT_TLS: 4310 if (symp->st_shndx != SHN_UNDEF) 4311 break; 4312 #ifndef __mips__ 4313 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4314 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4315 break; 4316 /* fallthrough */ 4317 #endif 4318 default: 4319 return (false); 4320 } 4321 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4322 return (false); 4323 4324 if (req->ventry == NULL) { 4325 if (obj->versyms != NULL) { 4326 verndx = VER_NDX(obj->versyms[symnum]); 4327 if (verndx > obj->vernum) { 4328 _rtld_error( 4329 "%s: symbol %s references wrong version %d", 4330 obj->path, obj->strtab + symnum, verndx); 4331 return (false); 4332 } 4333 /* 4334 * If we are not called from dlsym (i.e. this 4335 * is a normal relocation from unversioned 4336 * binary), accept the symbol immediately if 4337 * it happens to have first version after this 4338 * shared object became versioned. Otherwise, 4339 * if symbol is versioned and not hidden, 4340 * remember it. If it is the only symbol with 4341 * this name exported by the shared object, it 4342 * will be returned as a match by the calling 4343 * function. If symbol is global (verndx < 2) 4344 * accept it unconditionally. 4345 */ 4346 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4347 verndx == VER_NDX_GIVEN) { 4348 result->sym_out = symp; 4349 return (true); 4350 } 4351 else if (verndx >= VER_NDX_GIVEN) { 4352 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4353 == 0) { 4354 if (result->vsymp == NULL) 4355 result->vsymp = symp; 4356 result->vcount++; 4357 } 4358 return (false); 4359 } 4360 } 4361 result->sym_out = symp; 4362 return (true); 4363 } 4364 if (obj->versyms == NULL) { 4365 if (object_match_name(obj, req->ventry->name)) { 4366 _rtld_error("%s: object %s should provide version %s " 4367 "for symbol %s", obj_rtld.path, obj->path, 4368 req->ventry->name, obj->strtab + symnum); 4369 return (false); 4370 } 4371 } else { 4372 verndx = VER_NDX(obj->versyms[symnum]); 4373 if (verndx > obj->vernum) { 4374 _rtld_error("%s: symbol %s references wrong version %d", 4375 obj->path, obj->strtab + symnum, verndx); 4376 return (false); 4377 } 4378 if (obj->vertab[verndx].hash != req->ventry->hash || 4379 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4380 /* 4381 * Version does not match. Look if this is a 4382 * global symbol and if it is not hidden. If 4383 * global symbol (verndx < 2) is available, 4384 * use it. Do not return symbol if we are 4385 * called by dlvsym, because dlvsym looks for 4386 * a specific version and default one is not 4387 * what dlvsym wants. 4388 */ 4389 if ((req->flags & SYMLOOK_DLSYM) || 4390 (verndx >= VER_NDX_GIVEN) || 4391 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4392 return (false); 4393 } 4394 } 4395 result->sym_out = symp; 4396 return (true); 4397 } 4398 4399 /* 4400 * Search for symbol using SysV hash function. 4401 * obj->buckets is known not to be NULL at this point; the test for this was 4402 * performed with the obj->valid_hash_sysv assignment. 4403 */ 4404 static int 4405 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4406 { 4407 unsigned long symnum; 4408 Sym_Match_Result matchres; 4409 4410 matchres.sym_out = NULL; 4411 matchres.vsymp = NULL; 4412 matchres.vcount = 0; 4413 4414 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4415 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4416 if (symnum >= obj->nchains) 4417 return (ESRCH); /* Bad object */ 4418 4419 if (matched_symbol(req, obj, &matchres, symnum)) { 4420 req->sym_out = matchres.sym_out; 4421 req->defobj_out = obj; 4422 return (0); 4423 } 4424 } 4425 if (matchres.vcount == 1) { 4426 req->sym_out = matchres.vsymp; 4427 req->defobj_out = obj; 4428 return (0); 4429 } 4430 return (ESRCH); 4431 } 4432 4433 /* Search for symbol using GNU hash function */ 4434 static int 4435 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4436 { 4437 Elf_Addr bloom_word; 4438 const Elf32_Word *hashval; 4439 Elf32_Word bucket; 4440 Sym_Match_Result matchres; 4441 unsigned int h1, h2; 4442 unsigned long symnum; 4443 4444 matchres.sym_out = NULL; 4445 matchres.vsymp = NULL; 4446 matchres.vcount = 0; 4447 4448 /* Pick right bitmask word from Bloom filter array */ 4449 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4450 obj->maskwords_bm_gnu]; 4451 4452 /* Calculate modulus word size of gnu hash and its derivative */ 4453 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4454 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4455 4456 /* Filter out the "definitely not in set" queries */ 4457 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4458 return (ESRCH); 4459 4460 /* Locate hash chain and corresponding value element*/ 4461 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4462 if (bucket == 0) 4463 return (ESRCH); 4464 hashval = &obj->chain_zero_gnu[bucket]; 4465 do { 4466 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4467 symnum = hashval - obj->chain_zero_gnu; 4468 if (matched_symbol(req, obj, &matchres, symnum)) { 4469 req->sym_out = matchres.sym_out; 4470 req->defobj_out = obj; 4471 return (0); 4472 } 4473 } 4474 } while ((*hashval++ & 1) == 0); 4475 if (matchres.vcount == 1) { 4476 req->sym_out = matchres.vsymp; 4477 req->defobj_out = obj; 4478 return (0); 4479 } 4480 return (ESRCH); 4481 } 4482 4483 static void 4484 trace_loaded_objects(Obj_Entry *obj) 4485 { 4486 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4487 int c; 4488 4489 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4490 main_local = ""; 4491 4492 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4493 fmt1 = "\t%o => %p (%x)\n"; 4494 4495 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4496 fmt2 = "\t%o (%x)\n"; 4497 4498 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4499 4500 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4501 Needed_Entry *needed; 4502 char *name, *path; 4503 bool is_lib; 4504 4505 if (obj->marker) 4506 continue; 4507 if (list_containers && obj->needed != NULL) 4508 rtld_printf("%s:\n", obj->path); 4509 for (needed = obj->needed; needed; needed = needed->next) { 4510 if (needed->obj != NULL) { 4511 if (needed->obj->traced && !list_containers) 4512 continue; 4513 needed->obj->traced = true; 4514 path = needed->obj->path; 4515 } else 4516 path = "not found"; 4517 4518 name = (char *)obj->strtab + needed->name; 4519 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4520 4521 fmt = is_lib ? fmt1 : fmt2; 4522 while ((c = *fmt++) != '\0') { 4523 switch (c) { 4524 default: 4525 rtld_putchar(c); 4526 continue; 4527 case '\\': 4528 switch (c = *fmt) { 4529 case '\0': 4530 continue; 4531 case 'n': 4532 rtld_putchar('\n'); 4533 break; 4534 case 't': 4535 rtld_putchar('\t'); 4536 break; 4537 } 4538 break; 4539 case '%': 4540 switch (c = *fmt) { 4541 case '\0': 4542 continue; 4543 case '%': 4544 default: 4545 rtld_putchar(c); 4546 break; 4547 case 'A': 4548 rtld_putstr(main_local); 4549 break; 4550 case 'a': 4551 rtld_putstr(obj_main->path); 4552 break; 4553 case 'o': 4554 rtld_putstr(name); 4555 break; 4556 #if 0 4557 case 'm': 4558 rtld_printf("%d", sodp->sod_major); 4559 break; 4560 case 'n': 4561 rtld_printf("%d", sodp->sod_minor); 4562 break; 4563 #endif 4564 case 'p': 4565 rtld_putstr(path); 4566 break; 4567 case 'x': 4568 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4569 0); 4570 break; 4571 } 4572 break; 4573 } 4574 ++fmt; 4575 } 4576 } 4577 } 4578 } 4579 4580 /* 4581 * Unload a dlopened object and its dependencies from memory and from 4582 * our data structures. It is assumed that the DAG rooted in the 4583 * object has already been unreferenced, and that the object has a 4584 * reference count of 0. 4585 */ 4586 static void 4587 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4588 { 4589 Obj_Entry marker, *obj, *next; 4590 4591 assert(root->refcount == 0); 4592 4593 /* 4594 * Pass over the DAG removing unreferenced objects from 4595 * appropriate lists. 4596 */ 4597 unlink_object(root); 4598 4599 /* Unmap all objects that are no longer referenced. */ 4600 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4601 next = TAILQ_NEXT(obj, next); 4602 if (obj->marker || obj->refcount != 0) 4603 continue; 4604 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4605 obj->mapsize, 0, obj->path); 4606 dbg("unloading \"%s\"", obj->path); 4607 /* 4608 * Unlink the object now to prevent new references from 4609 * being acquired while the bind lock is dropped in 4610 * recursive dlclose() invocations. 4611 */ 4612 TAILQ_REMOVE(&obj_list, obj, next); 4613 obj_count--; 4614 4615 if (obj->filtees_loaded) { 4616 if (next != NULL) { 4617 init_marker(&marker); 4618 TAILQ_INSERT_BEFORE(next, &marker, next); 4619 unload_filtees(obj, lockstate); 4620 next = TAILQ_NEXT(&marker, next); 4621 TAILQ_REMOVE(&obj_list, &marker, next); 4622 } else 4623 unload_filtees(obj, lockstate); 4624 } 4625 release_object(obj); 4626 } 4627 } 4628 4629 static void 4630 unlink_object(Obj_Entry *root) 4631 { 4632 Objlist_Entry *elm; 4633 4634 if (root->refcount == 0) { 4635 /* Remove the object from the RTLD_GLOBAL list. */ 4636 objlist_remove(&list_global, root); 4637 4638 /* Remove the object from all objects' DAG lists. */ 4639 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4640 objlist_remove(&elm->obj->dldags, root); 4641 if (elm->obj != root) 4642 unlink_object(elm->obj); 4643 } 4644 } 4645 } 4646 4647 static void 4648 ref_dag(Obj_Entry *root) 4649 { 4650 Objlist_Entry *elm; 4651 4652 assert(root->dag_inited); 4653 STAILQ_FOREACH(elm, &root->dagmembers, link) 4654 elm->obj->refcount++; 4655 } 4656 4657 static void 4658 unref_dag(Obj_Entry *root) 4659 { 4660 Objlist_Entry *elm; 4661 4662 assert(root->dag_inited); 4663 STAILQ_FOREACH(elm, &root->dagmembers, link) 4664 elm->obj->refcount--; 4665 } 4666 4667 /* 4668 * Common code for MD __tls_get_addr(). 4669 */ 4670 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4671 static void * 4672 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4673 { 4674 Elf_Addr *newdtv, *dtv; 4675 RtldLockState lockstate; 4676 int to_copy; 4677 4678 dtv = *dtvp; 4679 /* Check dtv generation in case new modules have arrived */ 4680 if (dtv[0] != tls_dtv_generation) { 4681 wlock_acquire(rtld_bind_lock, &lockstate); 4682 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4683 to_copy = dtv[1]; 4684 if (to_copy > tls_max_index) 4685 to_copy = tls_max_index; 4686 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4687 newdtv[0] = tls_dtv_generation; 4688 newdtv[1] = tls_max_index; 4689 free(dtv); 4690 lock_release(rtld_bind_lock, &lockstate); 4691 dtv = *dtvp = newdtv; 4692 } 4693 4694 /* Dynamically allocate module TLS if necessary */ 4695 if (dtv[index + 1] == 0) { 4696 /* Signal safe, wlock will block out signals. */ 4697 wlock_acquire(rtld_bind_lock, &lockstate); 4698 if (!dtv[index + 1]) 4699 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4700 lock_release(rtld_bind_lock, &lockstate); 4701 } 4702 return ((void *)(dtv[index + 1] + offset)); 4703 } 4704 4705 void * 4706 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4707 { 4708 Elf_Addr *dtv; 4709 4710 dtv = *dtvp; 4711 /* Check dtv generation in case new modules have arrived */ 4712 if (__predict_true(dtv[0] == tls_dtv_generation && 4713 dtv[index + 1] != 0)) 4714 return ((void *)(dtv[index + 1] + offset)); 4715 return (tls_get_addr_slow(dtvp, index, offset)); 4716 } 4717 4718 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4719 defined(__powerpc__) || defined(__riscv) 4720 4721 /* 4722 * Return pointer to allocated TLS block 4723 */ 4724 static void * 4725 get_tls_block_ptr(void *tcb, size_t tcbsize) 4726 { 4727 size_t extra_size, post_size, pre_size, tls_block_size; 4728 size_t tls_init_align; 4729 4730 tls_init_align = MAX(obj_main->tlsalign, 1); 4731 4732 /* Compute fragments sizes. */ 4733 extra_size = tcbsize - TLS_TCB_SIZE; 4734 post_size = calculate_tls_post_size(tls_init_align); 4735 tls_block_size = tcbsize + post_size; 4736 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4737 4738 return ((char *)tcb - pre_size - extra_size); 4739 } 4740 4741 /* 4742 * Allocate Static TLS using the Variant I method. 4743 * 4744 * For details on the layout, see lib/libc/gen/tls.c. 4745 * 4746 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4747 * it is based on tls_last_offset, and TLS offsets here are really TCB 4748 * offsets, whereas libc's tls_static_space is just the executable's static 4749 * TLS segment. 4750 */ 4751 void * 4752 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4753 { 4754 Obj_Entry *obj; 4755 char *tls_block; 4756 Elf_Addr *dtv, **tcb; 4757 Elf_Addr addr; 4758 int i; 4759 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4760 size_t tls_init_align; 4761 4762 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4763 return (oldtcb); 4764 4765 assert(tcbsize >= TLS_TCB_SIZE); 4766 maxalign = MAX(tcbalign, tls_static_max_align); 4767 tls_init_align = MAX(obj_main->tlsalign, 1); 4768 4769 /* Compute fragmets sizes. */ 4770 extra_size = tcbsize - TLS_TCB_SIZE; 4771 post_size = calculate_tls_post_size(tls_init_align); 4772 tls_block_size = tcbsize + post_size; 4773 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4774 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4775 4776 /* Allocate whole TLS block */ 4777 tls_block = malloc_aligned(tls_block_size, maxalign); 4778 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4779 4780 if (oldtcb != NULL) { 4781 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4782 tls_static_space); 4783 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4784 4785 /* Adjust the DTV. */ 4786 dtv = tcb[0]; 4787 for (i = 0; i < dtv[1]; i++) { 4788 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4789 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4790 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4791 } 4792 } 4793 } else { 4794 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4795 tcb[0] = dtv; 4796 dtv[0] = tls_dtv_generation; 4797 dtv[1] = tls_max_index; 4798 4799 for (obj = globallist_curr(objs); obj != NULL; 4800 obj = globallist_next(obj)) { 4801 if (obj->tlsoffset > 0) { 4802 addr = (Elf_Addr)tcb + obj->tlsoffset; 4803 if (obj->tlsinitsize > 0) 4804 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4805 if (obj->tlssize > obj->tlsinitsize) 4806 memset((void*) (addr + obj->tlsinitsize), 0, 4807 obj->tlssize - obj->tlsinitsize); 4808 dtv[obj->tlsindex + 1] = addr; 4809 } 4810 } 4811 } 4812 4813 return (tcb); 4814 } 4815 4816 void 4817 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4818 { 4819 Elf_Addr *dtv; 4820 Elf_Addr tlsstart, tlsend; 4821 size_t post_size; 4822 size_t dtvsize, i, tls_init_align; 4823 4824 assert(tcbsize >= TLS_TCB_SIZE); 4825 tls_init_align = MAX(obj_main->tlsalign, 1); 4826 4827 /* Compute fragments sizes. */ 4828 post_size = calculate_tls_post_size(tls_init_align); 4829 4830 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4831 tlsend = (Elf_Addr)tcb + tls_static_space; 4832 4833 dtv = *(Elf_Addr **)tcb; 4834 dtvsize = dtv[1]; 4835 for (i = 0; i < dtvsize; i++) { 4836 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4837 free((void*)dtv[i+2]); 4838 } 4839 } 4840 free(dtv); 4841 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4842 } 4843 4844 #endif 4845 4846 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4847 4848 /* 4849 * Allocate Static TLS using the Variant II method. 4850 */ 4851 void * 4852 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4853 { 4854 Obj_Entry *obj; 4855 size_t size, ralign; 4856 char *tls; 4857 Elf_Addr *dtv, *olddtv; 4858 Elf_Addr segbase, oldsegbase, addr; 4859 int i; 4860 4861 ralign = tcbalign; 4862 if (tls_static_max_align > ralign) 4863 ralign = tls_static_max_align; 4864 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4865 4866 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4867 tls = malloc_aligned(size, ralign); 4868 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4869 4870 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4871 ((Elf_Addr*)segbase)[0] = segbase; 4872 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4873 4874 dtv[0] = tls_dtv_generation; 4875 dtv[1] = tls_max_index; 4876 4877 if (oldtls) { 4878 /* 4879 * Copy the static TLS block over whole. 4880 */ 4881 oldsegbase = (Elf_Addr) oldtls; 4882 memcpy((void *)(segbase - tls_static_space), 4883 (const void *)(oldsegbase - tls_static_space), 4884 tls_static_space); 4885 4886 /* 4887 * If any dynamic TLS blocks have been created tls_get_addr(), 4888 * move them over. 4889 */ 4890 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4891 for (i = 0; i < olddtv[1]; i++) { 4892 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4893 dtv[i+2] = olddtv[i+2]; 4894 olddtv[i+2] = 0; 4895 } 4896 } 4897 4898 /* 4899 * We assume that this block was the one we created with 4900 * allocate_initial_tls(). 4901 */ 4902 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4903 } else { 4904 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4905 if (obj->marker || obj->tlsoffset == 0) 4906 continue; 4907 addr = segbase - obj->tlsoffset; 4908 memset((void*) (addr + obj->tlsinitsize), 4909 0, obj->tlssize - obj->tlsinitsize); 4910 if (obj->tlsinit) 4911 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4912 dtv[obj->tlsindex + 1] = addr; 4913 } 4914 } 4915 4916 return (void*) segbase; 4917 } 4918 4919 void 4920 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4921 { 4922 Elf_Addr* dtv; 4923 size_t size, ralign; 4924 int dtvsize, i; 4925 Elf_Addr tlsstart, tlsend; 4926 4927 /* 4928 * Figure out the size of the initial TLS block so that we can 4929 * find stuff which ___tls_get_addr() allocated dynamically. 4930 */ 4931 ralign = tcbalign; 4932 if (tls_static_max_align > ralign) 4933 ralign = tls_static_max_align; 4934 size = round(tls_static_space, ralign); 4935 4936 dtv = ((Elf_Addr**)tls)[1]; 4937 dtvsize = dtv[1]; 4938 tlsend = (Elf_Addr) tls; 4939 tlsstart = tlsend - size; 4940 for (i = 0; i < dtvsize; i++) { 4941 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4942 free_aligned((void *)dtv[i + 2]); 4943 } 4944 } 4945 4946 free_aligned((void *)tlsstart); 4947 free((void*) dtv); 4948 } 4949 4950 #endif 4951 4952 /* 4953 * Allocate TLS block for module with given index. 4954 */ 4955 void * 4956 allocate_module_tls(int index) 4957 { 4958 Obj_Entry* obj; 4959 char* p; 4960 4961 TAILQ_FOREACH(obj, &obj_list, next) { 4962 if (obj->marker) 4963 continue; 4964 if (obj->tlsindex == index) 4965 break; 4966 } 4967 if (!obj) { 4968 _rtld_error("Can't find module with TLS index %d", index); 4969 rtld_die(); 4970 } 4971 4972 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4973 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4974 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4975 4976 return p; 4977 } 4978 4979 bool 4980 allocate_tls_offset(Obj_Entry *obj) 4981 { 4982 size_t off; 4983 4984 if (obj->tls_done) 4985 return true; 4986 4987 if (obj->tlssize == 0) { 4988 obj->tls_done = true; 4989 return true; 4990 } 4991 4992 if (tls_last_offset == 0) 4993 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4994 else 4995 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4996 obj->tlssize, obj->tlsalign); 4997 4998 /* 4999 * If we have already fixed the size of the static TLS block, we 5000 * must stay within that size. When allocating the static TLS, we 5001 * leave a small amount of space spare to be used for dynamically 5002 * loading modules which use static TLS. 5003 */ 5004 if (tls_static_space != 0) { 5005 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5006 return false; 5007 } else if (obj->tlsalign > tls_static_max_align) { 5008 tls_static_max_align = obj->tlsalign; 5009 } 5010 5011 tls_last_offset = obj->tlsoffset = off; 5012 tls_last_size = obj->tlssize; 5013 obj->tls_done = true; 5014 5015 return true; 5016 } 5017 5018 void 5019 free_tls_offset(Obj_Entry *obj) 5020 { 5021 5022 /* 5023 * If we were the last thing to allocate out of the static TLS 5024 * block, we give our space back to the 'allocator'. This is a 5025 * simplistic workaround to allow libGL.so.1 to be loaded and 5026 * unloaded multiple times. 5027 */ 5028 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5029 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5030 tls_last_offset -= obj->tlssize; 5031 tls_last_size = 0; 5032 } 5033 } 5034 5035 void * 5036 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5037 { 5038 void *ret; 5039 RtldLockState lockstate; 5040 5041 wlock_acquire(rtld_bind_lock, &lockstate); 5042 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5043 tcbsize, tcbalign); 5044 lock_release(rtld_bind_lock, &lockstate); 5045 return (ret); 5046 } 5047 5048 void 5049 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5050 { 5051 RtldLockState lockstate; 5052 5053 wlock_acquire(rtld_bind_lock, &lockstate); 5054 free_tls(tcb, tcbsize, tcbalign); 5055 lock_release(rtld_bind_lock, &lockstate); 5056 } 5057 5058 static void 5059 object_add_name(Obj_Entry *obj, const char *name) 5060 { 5061 Name_Entry *entry; 5062 size_t len; 5063 5064 len = strlen(name); 5065 entry = malloc(sizeof(Name_Entry) + len); 5066 5067 if (entry != NULL) { 5068 strcpy(entry->name, name); 5069 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5070 } 5071 } 5072 5073 static int 5074 object_match_name(const Obj_Entry *obj, const char *name) 5075 { 5076 Name_Entry *entry; 5077 5078 STAILQ_FOREACH(entry, &obj->names, link) { 5079 if (strcmp(name, entry->name) == 0) 5080 return (1); 5081 } 5082 return (0); 5083 } 5084 5085 static Obj_Entry * 5086 locate_dependency(const Obj_Entry *obj, const char *name) 5087 { 5088 const Objlist_Entry *entry; 5089 const Needed_Entry *needed; 5090 5091 STAILQ_FOREACH(entry, &list_main, link) { 5092 if (object_match_name(entry->obj, name)) 5093 return entry->obj; 5094 } 5095 5096 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5097 if (strcmp(obj->strtab + needed->name, name) == 0 || 5098 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5099 /* 5100 * If there is DT_NEEDED for the name we are looking for, 5101 * we are all set. Note that object might not be found if 5102 * dependency was not loaded yet, so the function can 5103 * return NULL here. This is expected and handled 5104 * properly by the caller. 5105 */ 5106 return (needed->obj); 5107 } 5108 } 5109 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5110 obj->path, name); 5111 rtld_die(); 5112 } 5113 5114 static int 5115 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5116 const Elf_Vernaux *vna) 5117 { 5118 const Elf_Verdef *vd; 5119 const char *vername; 5120 5121 vername = refobj->strtab + vna->vna_name; 5122 vd = depobj->verdef; 5123 if (vd == NULL) { 5124 _rtld_error("%s: version %s required by %s not defined", 5125 depobj->path, vername, refobj->path); 5126 return (-1); 5127 } 5128 for (;;) { 5129 if (vd->vd_version != VER_DEF_CURRENT) { 5130 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5131 depobj->path, vd->vd_version); 5132 return (-1); 5133 } 5134 if (vna->vna_hash == vd->vd_hash) { 5135 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5136 ((char *)vd + vd->vd_aux); 5137 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5138 return (0); 5139 } 5140 if (vd->vd_next == 0) 5141 break; 5142 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5143 } 5144 if (vna->vna_flags & VER_FLG_WEAK) 5145 return (0); 5146 _rtld_error("%s: version %s required by %s not found", 5147 depobj->path, vername, refobj->path); 5148 return (-1); 5149 } 5150 5151 static int 5152 rtld_verify_object_versions(Obj_Entry *obj) 5153 { 5154 const Elf_Verneed *vn; 5155 const Elf_Verdef *vd; 5156 const Elf_Verdaux *vda; 5157 const Elf_Vernaux *vna; 5158 const Obj_Entry *depobj; 5159 int maxvernum, vernum; 5160 5161 if (obj->ver_checked) 5162 return (0); 5163 obj->ver_checked = true; 5164 5165 maxvernum = 0; 5166 /* 5167 * Walk over defined and required version records and figure out 5168 * max index used by any of them. Do very basic sanity checking 5169 * while there. 5170 */ 5171 vn = obj->verneed; 5172 while (vn != NULL) { 5173 if (vn->vn_version != VER_NEED_CURRENT) { 5174 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5175 obj->path, vn->vn_version); 5176 return (-1); 5177 } 5178 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5179 for (;;) { 5180 vernum = VER_NEED_IDX(vna->vna_other); 5181 if (vernum > maxvernum) 5182 maxvernum = vernum; 5183 if (vna->vna_next == 0) 5184 break; 5185 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5186 } 5187 if (vn->vn_next == 0) 5188 break; 5189 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5190 } 5191 5192 vd = obj->verdef; 5193 while (vd != NULL) { 5194 if (vd->vd_version != VER_DEF_CURRENT) { 5195 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5196 obj->path, vd->vd_version); 5197 return (-1); 5198 } 5199 vernum = VER_DEF_IDX(vd->vd_ndx); 5200 if (vernum > maxvernum) 5201 maxvernum = vernum; 5202 if (vd->vd_next == 0) 5203 break; 5204 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5205 } 5206 5207 if (maxvernum == 0) 5208 return (0); 5209 5210 /* 5211 * Store version information in array indexable by version index. 5212 * Verify that object version requirements are satisfied along the 5213 * way. 5214 */ 5215 obj->vernum = maxvernum + 1; 5216 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5217 5218 vd = obj->verdef; 5219 while (vd != NULL) { 5220 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5221 vernum = VER_DEF_IDX(vd->vd_ndx); 5222 assert(vernum <= maxvernum); 5223 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5224 obj->vertab[vernum].hash = vd->vd_hash; 5225 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5226 obj->vertab[vernum].file = NULL; 5227 obj->vertab[vernum].flags = 0; 5228 } 5229 if (vd->vd_next == 0) 5230 break; 5231 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5232 } 5233 5234 vn = obj->verneed; 5235 while (vn != NULL) { 5236 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5237 if (depobj == NULL) 5238 return (-1); 5239 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5240 for (;;) { 5241 if (check_object_provided_version(obj, depobj, vna)) 5242 return (-1); 5243 vernum = VER_NEED_IDX(vna->vna_other); 5244 assert(vernum <= maxvernum); 5245 obj->vertab[vernum].hash = vna->vna_hash; 5246 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5247 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5248 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5249 VER_INFO_HIDDEN : 0; 5250 if (vna->vna_next == 0) 5251 break; 5252 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5253 } 5254 if (vn->vn_next == 0) 5255 break; 5256 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5257 } 5258 return 0; 5259 } 5260 5261 static int 5262 rtld_verify_versions(const Objlist *objlist) 5263 { 5264 Objlist_Entry *entry; 5265 int rc; 5266 5267 rc = 0; 5268 STAILQ_FOREACH(entry, objlist, link) { 5269 /* 5270 * Skip dummy objects or objects that have their version requirements 5271 * already checked. 5272 */ 5273 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5274 continue; 5275 if (rtld_verify_object_versions(entry->obj) == -1) { 5276 rc = -1; 5277 if (ld_tracing == NULL) 5278 break; 5279 } 5280 } 5281 if (rc == 0 || ld_tracing != NULL) 5282 rc = rtld_verify_object_versions(&obj_rtld); 5283 return rc; 5284 } 5285 5286 const Ver_Entry * 5287 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5288 { 5289 Elf_Versym vernum; 5290 5291 if (obj->vertab) { 5292 vernum = VER_NDX(obj->versyms[symnum]); 5293 if (vernum >= obj->vernum) { 5294 _rtld_error("%s: symbol %s has wrong verneed value %d", 5295 obj->path, obj->strtab + symnum, vernum); 5296 } else if (obj->vertab[vernum].hash != 0) { 5297 return &obj->vertab[vernum]; 5298 } 5299 } 5300 return NULL; 5301 } 5302 5303 int 5304 _rtld_get_stack_prot(void) 5305 { 5306 5307 return (stack_prot); 5308 } 5309 5310 int 5311 _rtld_is_dlopened(void *arg) 5312 { 5313 Obj_Entry *obj; 5314 RtldLockState lockstate; 5315 int res; 5316 5317 rlock_acquire(rtld_bind_lock, &lockstate); 5318 obj = dlcheck(arg); 5319 if (obj == NULL) 5320 obj = obj_from_addr(arg); 5321 if (obj == NULL) { 5322 _rtld_error("No shared object contains address"); 5323 lock_release(rtld_bind_lock, &lockstate); 5324 return (-1); 5325 } 5326 res = obj->dlopened ? 1 : 0; 5327 lock_release(rtld_bind_lock, &lockstate); 5328 return (res); 5329 } 5330 5331 int 5332 obj_enforce_relro(Obj_Entry *obj) 5333 { 5334 5335 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5336 PROT_READ) == -1) { 5337 _rtld_error("%s: Cannot enforce relro protection: %s", 5338 obj->path, rtld_strerror(errno)); 5339 return (-1); 5340 } 5341 return (0); 5342 } 5343 5344 static void 5345 map_stacks_exec(RtldLockState *lockstate) 5346 { 5347 void (*thr_map_stacks_exec)(void); 5348 5349 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5350 return; 5351 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5352 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5353 if (thr_map_stacks_exec != NULL) { 5354 stack_prot |= PROT_EXEC; 5355 thr_map_stacks_exec(); 5356 } 5357 } 5358 5359 void 5360 symlook_init(SymLook *dst, const char *name) 5361 { 5362 5363 bzero(dst, sizeof(*dst)); 5364 dst->name = name; 5365 dst->hash = elf_hash(name); 5366 dst->hash_gnu = gnu_hash(name); 5367 } 5368 5369 static void 5370 symlook_init_from_req(SymLook *dst, const SymLook *src) 5371 { 5372 5373 dst->name = src->name; 5374 dst->hash = src->hash; 5375 dst->hash_gnu = src->hash_gnu; 5376 dst->ventry = src->ventry; 5377 dst->flags = src->flags; 5378 dst->defobj_out = NULL; 5379 dst->sym_out = NULL; 5380 dst->lockstate = src->lockstate; 5381 } 5382 5383 static int 5384 open_binary_fd(const char *argv0, bool search_in_path) 5385 { 5386 char *pathenv, *pe, binpath[PATH_MAX]; 5387 int fd; 5388 5389 if (search_in_path && strchr(argv0, '/') == NULL) { 5390 pathenv = getenv("PATH"); 5391 if (pathenv == NULL) { 5392 _rtld_error("-p and no PATH environment variable"); 5393 rtld_die(); 5394 } 5395 pathenv = strdup(pathenv); 5396 if (pathenv == NULL) { 5397 _rtld_error("Cannot allocate memory"); 5398 rtld_die(); 5399 } 5400 fd = -1; 5401 errno = ENOENT; 5402 while ((pe = strsep(&pathenv, ":")) != NULL) { 5403 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5404 sizeof(binpath)) 5405 continue; 5406 if (binpath[0] != '\0' && 5407 strlcat(binpath, "/", sizeof(binpath)) >= 5408 sizeof(binpath)) 5409 continue; 5410 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5411 sizeof(binpath)) 5412 continue; 5413 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5414 if (fd != -1 || errno != ENOENT) 5415 break; 5416 } 5417 free(pathenv); 5418 } else { 5419 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5420 } 5421 5422 if (fd == -1) { 5423 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5424 rtld_die(); 5425 } 5426 return (fd); 5427 } 5428 5429 /* 5430 * Parse a set of command-line arguments. 5431 */ 5432 static int 5433 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5434 { 5435 const char *arg; 5436 int fd, i, j, arglen; 5437 char opt; 5438 5439 dbg("Parsing command-line arguments"); 5440 *use_pathp = false; 5441 *fdp = -1; 5442 5443 for (i = 1; i < argc; i++ ) { 5444 arg = argv[i]; 5445 dbg("argv[%d]: '%s'", i, arg); 5446 5447 /* 5448 * rtld arguments end with an explicit "--" or with the first 5449 * non-prefixed argument. 5450 */ 5451 if (strcmp(arg, "--") == 0) { 5452 i++; 5453 break; 5454 } 5455 if (arg[0] != '-') 5456 break; 5457 5458 /* 5459 * All other arguments are single-character options that can 5460 * be combined, so we need to search through `arg` for them. 5461 */ 5462 arglen = strlen(arg); 5463 for (j = 1; j < arglen; j++) { 5464 opt = arg[j]; 5465 if (opt == 'h') { 5466 print_usage(argv[0]); 5467 _exit(0); 5468 } else if (opt == 'f') { 5469 /* 5470 * -f XX can be used to specify a descriptor for the 5471 * binary named at the command line (i.e., the later 5472 * argument will specify the process name but the 5473 * descriptor is what will actually be executed) 5474 */ 5475 if (j != arglen - 1) { 5476 /* -f must be the last option in, e.g., -abcf */ 5477 _rtld_error("Invalid options: %s", arg); 5478 rtld_die(); 5479 } 5480 i++; 5481 fd = parse_integer(argv[i]); 5482 if (fd == -1) { 5483 _rtld_error("Invalid file descriptor: '%s'", 5484 argv[i]); 5485 rtld_die(); 5486 } 5487 *fdp = fd; 5488 break; 5489 } else if (opt == 'p') { 5490 *use_pathp = true; 5491 } else { 5492 _rtld_error("Invalid argument: '%s'", arg); 5493 print_usage(argv[0]); 5494 rtld_die(); 5495 } 5496 } 5497 } 5498 5499 return (i); 5500 } 5501 5502 /* 5503 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5504 */ 5505 static int 5506 parse_integer(const char *str) 5507 { 5508 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5509 const char *orig; 5510 int n; 5511 char c; 5512 5513 orig = str; 5514 n = 0; 5515 for (c = *str; c != '\0'; c = *++str) { 5516 if (c < '0' || c > '9') 5517 return (-1); 5518 5519 n *= RADIX; 5520 n += c - '0'; 5521 } 5522 5523 /* Make sure we actually parsed something. */ 5524 if (str == orig) 5525 return (-1); 5526 return (n); 5527 } 5528 5529 static void 5530 print_usage(const char *argv0) 5531 { 5532 5533 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5534 "\n" 5535 "Options:\n" 5536 " -h Display this help message\n" 5537 " -p Search in PATH for named binary\n" 5538 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5539 " -- End of RTLD options\n" 5540 " <binary> Name of process to execute\n" 5541 " <args> Arguments to the executed process\n", argv0); 5542 } 5543 5544 /* 5545 * Overrides for libc_pic-provided functions. 5546 */ 5547 5548 int 5549 __getosreldate(void) 5550 { 5551 size_t len; 5552 int oid[2]; 5553 int error, osrel; 5554 5555 if (osreldate != 0) 5556 return (osreldate); 5557 5558 oid[0] = CTL_KERN; 5559 oid[1] = KERN_OSRELDATE; 5560 osrel = 0; 5561 len = sizeof(osrel); 5562 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5563 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5564 osreldate = osrel; 5565 return (osreldate); 5566 } 5567 5568 void 5569 exit(int status) 5570 { 5571 5572 _exit(status); 5573 } 5574 5575 void (*__cleanup)(void); 5576 int __isthreaded = 0; 5577 int _thread_autoinit_dummy_decl = 1; 5578 5579 /* 5580 * No unresolved symbols for rtld. 5581 */ 5582 void 5583 __pthread_cxa_finalize(struct dl_phdr_info *a) 5584 { 5585 } 5586 5587 const char * 5588 rtld_strerror(int errnum) 5589 { 5590 5591 if (errnum < 0 || errnum >= sys_nerr) 5592 return ("Unknown error"); 5593 return (sys_errlist[errnum]); 5594 } 5595