1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_utrace.h" 70 #include "notes.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(void); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 77 /* Variables that cannot be static: */ 78 extern struct r_debug r_debug; /* For GDB */ 79 extern int _thread_autoinit_dummy_decl; 80 extern char* __progname; 81 extern void (*__cleanup)(void); 82 83 84 /* 85 * Function declarations. 86 */ 87 static const char *basename(const char *); 88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 89 const Elf_Dyn **, const Elf_Dyn **); 90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 91 const Elf_Dyn *); 92 static void digest_dynamic(Obj_Entry *, int); 93 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 94 static Obj_Entry *dlcheck(void *); 95 static int dlclose_locked(void *, RtldLockState *); 96 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 97 int lo_flags, int mode, RtldLockState *lockstate); 98 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 99 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 100 static bool donelist_check(DoneList *, const Obj_Entry *); 101 static void errmsg_restore(char *); 102 static char *errmsg_save(void); 103 static void *fill_search_info(const char *, size_t, void *); 104 static char *find_library(const char *, const Obj_Entry *, int *); 105 static const char *gethints(bool); 106 static void hold_object(Obj_Entry *); 107 static void unhold_object(Obj_Entry *); 108 static void init_dag(Obj_Entry *); 109 static void init_marker(Obj_Entry *); 110 static void init_pagesizes(Elf_Auxinfo **aux_info); 111 static void init_rtld(caddr_t, Elf_Auxinfo **); 112 static void initlist_add_neededs(Needed_Entry *, Objlist *); 113 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 114 static void linkmap_add(Obj_Entry *); 115 static void linkmap_delete(Obj_Entry *); 116 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 117 static void unload_filtees(Obj_Entry *, RtldLockState *); 118 static int load_needed_objects(Obj_Entry *, int); 119 static int load_preload_objects(void); 120 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 121 static void map_stacks_exec(RtldLockState *); 122 static int obj_enforce_relro(Obj_Entry *); 123 static Obj_Entry *obj_from_addr(const void *); 124 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 125 static void objlist_call_init(Objlist *, RtldLockState *); 126 static void objlist_clear(Objlist *); 127 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 128 static void objlist_init(Objlist *); 129 static void objlist_push_head(Objlist *, Obj_Entry *); 130 static void objlist_push_tail(Objlist *, Obj_Entry *); 131 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 132 static void objlist_remove(Objlist *, Obj_Entry *); 133 static int open_binary_fd(const char *argv0, bool search_in_path); 134 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 135 static int parse_integer(const char *); 136 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 137 static void print_usage(const char *argv0); 138 static void release_object(Obj_Entry *); 139 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 140 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 141 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 142 int flags, RtldLockState *lockstate); 143 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 144 RtldLockState *); 145 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 146 int flags, RtldLockState *lockstate); 147 static int rtld_dirname(const char *, char *); 148 static int rtld_dirname_abs(const char *, char *); 149 static void *rtld_dlopen(const char *name, int fd, int mode); 150 static void rtld_exit(void); 151 static char *search_library_path(const char *, const char *, const char *, 152 int *); 153 static char *search_library_pathfds(const char *, const char *, int *); 154 static const void **get_program_var_addr(const char *, RtldLockState *); 155 static void set_program_var(const char *, const void *); 156 static int symlook_default(SymLook *, const Obj_Entry *refobj); 157 static int symlook_global(SymLook *, DoneList *); 158 static void symlook_init_from_req(SymLook *, const SymLook *); 159 static int symlook_list(SymLook *, const Objlist *, DoneList *); 160 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 161 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 162 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 163 static void trace_loaded_objects(Obj_Entry *); 164 static void unlink_object(Obj_Entry *); 165 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 166 static void unref_dag(Obj_Entry *); 167 static void ref_dag(Obj_Entry *); 168 static char *origin_subst_one(Obj_Entry *, char *, const char *, 169 const char *, bool); 170 static char *origin_subst(Obj_Entry *, const char *); 171 static bool obj_resolve_origin(Obj_Entry *obj); 172 static void preinit_main(void); 173 static int rtld_verify_versions(const Objlist *); 174 static int rtld_verify_object_versions(Obj_Entry *); 175 static void object_add_name(Obj_Entry *, const char *); 176 static int object_match_name(const Obj_Entry *, const char *); 177 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 178 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 179 struct dl_phdr_info *phdr_info); 180 static uint32_t gnu_hash(const char *); 181 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 182 const unsigned long); 183 184 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 185 void _r_debug_postinit(struct link_map *) __noinline __exported; 186 187 int __sys_openat(int, const char *, int, ...); 188 189 /* 190 * Data declarations. 191 */ 192 static char *error_message; /* Message for dlerror(), or NULL */ 193 struct r_debug r_debug __exported; /* for GDB; */ 194 static bool libmap_disable; /* Disable libmap */ 195 static bool ld_loadfltr; /* Immediate filters processing */ 196 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 197 static bool trust; /* False for setuid and setgid programs */ 198 static bool dangerous_ld_env; /* True if environment variables have been 199 used to affect the libraries loaded */ 200 bool ld_bind_not; /* Disable PLT update */ 201 static char *ld_bind_now; /* Environment variable for immediate binding */ 202 static char *ld_debug; /* Environment variable for debugging */ 203 static char *ld_library_path; /* Environment variable for search path */ 204 static char *ld_library_dirs; /* Environment variable for library descriptors */ 205 static char *ld_preload; /* Environment variable for libraries to 206 load first */ 207 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 208 static const char *ld_tracing; /* Called from ldd to print libs */ 209 static char *ld_utrace; /* Use utrace() to log events. */ 210 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 211 static Obj_Entry *obj_main; /* The main program shared object */ 212 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 213 static unsigned int obj_count; /* Number of objects in obj_list */ 214 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 215 216 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 217 STAILQ_HEAD_INITIALIZER(list_global); 218 static Objlist list_main = /* Objects loaded at program startup */ 219 STAILQ_HEAD_INITIALIZER(list_main); 220 static Objlist list_fini = /* Objects needing fini() calls */ 221 STAILQ_HEAD_INITIALIZER(list_fini); 222 223 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 224 225 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 226 227 extern Elf_Dyn _DYNAMIC; 228 #pragma weak _DYNAMIC 229 230 int dlclose(void *) __exported; 231 char *dlerror(void) __exported; 232 void *dlopen(const char *, int) __exported; 233 void *fdlopen(int, int) __exported; 234 void *dlsym(void *, const char *) __exported; 235 dlfunc_t dlfunc(void *, const char *) __exported; 236 void *dlvsym(void *, const char *, const char *) __exported; 237 int dladdr(const void *, Dl_info *) __exported; 238 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 239 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 240 int dlinfo(void *, int , void *) __exported; 241 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 242 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 243 int _rtld_get_stack_prot(void) __exported; 244 int _rtld_is_dlopened(void *) __exported; 245 void _rtld_error(const char *, ...) __exported; 246 247 /* Only here to fix -Wmissing-prototypes warnings */ 248 int __getosreldate(void); 249 void __pthread_cxa_finalize(struct dl_phdr_info *a); 250 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 251 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 252 253 254 int npagesizes; 255 static int osreldate; 256 size_t *pagesizes; 257 258 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 259 static int max_stack_flags; 260 261 /* 262 * Global declarations normally provided by crt1. The dynamic linker is 263 * not built with crt1, so we have to provide them ourselves. 264 */ 265 char *__progname; 266 char **environ; 267 268 /* 269 * Used to pass argc, argv to init functions. 270 */ 271 int main_argc; 272 char **main_argv; 273 274 /* 275 * Globals to control TLS allocation. 276 */ 277 size_t tls_last_offset; /* Static TLS offset of last module */ 278 size_t tls_last_size; /* Static TLS size of last module */ 279 size_t tls_static_space; /* Static TLS space allocated */ 280 static size_t tls_static_max_align; 281 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 282 int tls_max_index = 1; /* Largest module index allocated */ 283 284 static bool ld_library_path_rpath = false; 285 286 /* 287 * Globals for path names, and such 288 */ 289 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 290 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 291 const char *ld_path_rtld = _PATH_RTLD; 292 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 293 const char *ld_env_prefix = LD_; 294 295 /* 296 * Fill in a DoneList with an allocation large enough to hold all of 297 * the currently-loaded objects. Keep this as a macro since it calls 298 * alloca and we want that to occur within the scope of the caller. 299 */ 300 #define donelist_init(dlp) \ 301 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 302 assert((dlp)->objs != NULL), \ 303 (dlp)->num_alloc = obj_count, \ 304 (dlp)->num_used = 0) 305 306 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 307 if (ld_utrace != NULL) \ 308 ld_utrace_log(e, h, mb, ms, r, n); \ 309 } while (0) 310 311 static void 312 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 313 int refcnt, const char *name) 314 { 315 struct utrace_rtld ut; 316 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 317 318 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 319 ut.event = event; 320 ut.handle = handle; 321 ut.mapbase = mapbase; 322 ut.mapsize = mapsize; 323 ut.refcnt = refcnt; 324 bzero(ut.name, sizeof(ut.name)); 325 if (name) 326 strlcpy(ut.name, name, sizeof(ut.name)); 327 utrace(&ut, sizeof(ut)); 328 } 329 330 #ifdef RTLD_VARIANT_ENV_NAMES 331 /* 332 * construct the env variable based on the type of binary that's 333 * running. 334 */ 335 static inline const char * 336 _LD(const char *var) 337 { 338 static char buffer[128]; 339 340 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 341 strlcat(buffer, var, sizeof(buffer)); 342 return (buffer); 343 } 344 #else 345 #define _LD(x) LD_ x 346 #endif 347 348 /* 349 * Main entry point for dynamic linking. The first argument is the 350 * stack pointer. The stack is expected to be laid out as described 351 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 352 * Specifically, the stack pointer points to a word containing 353 * ARGC. Following that in the stack is a null-terminated sequence 354 * of pointers to argument strings. Then comes a null-terminated 355 * sequence of pointers to environment strings. Finally, there is a 356 * sequence of "auxiliary vector" entries. 357 * 358 * The second argument points to a place to store the dynamic linker's 359 * exit procedure pointer and the third to a place to store the main 360 * program's object. 361 * 362 * The return value is the main program's entry point. 363 */ 364 func_ptr_type 365 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 366 { 367 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 368 Objlist_Entry *entry; 369 Obj_Entry *last_interposer, *obj, *preload_tail; 370 const Elf_Phdr *phdr; 371 Objlist initlist; 372 RtldLockState lockstate; 373 struct stat st; 374 Elf_Addr *argcp; 375 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 376 const char *argv0; 377 caddr_t imgentry; 378 char buf[MAXPATHLEN]; 379 int argc, fd, i, phnum, rtld_argc; 380 bool dir_enable, explicit_fd, search_in_path; 381 382 /* 383 * On entry, the dynamic linker itself has not been relocated yet. 384 * Be very careful not to reference any global data until after 385 * init_rtld has returned. It is OK to reference file-scope statics 386 * and string constants, and to call static and global functions. 387 */ 388 389 /* Find the auxiliary vector on the stack. */ 390 argcp = sp; 391 argc = *sp++; 392 argv = (char **) sp; 393 sp += argc + 1; /* Skip over arguments and NULL terminator */ 394 env = (char **) sp; 395 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 396 ; 397 aux = (Elf_Auxinfo *) sp; 398 399 /* Digest the auxiliary vector. */ 400 for (i = 0; i < AT_COUNT; i++) 401 aux_info[i] = NULL; 402 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 403 if (auxp->a_type < AT_COUNT) 404 aux_info[auxp->a_type] = auxp; 405 } 406 407 /* Initialize and relocate ourselves. */ 408 assert(aux_info[AT_BASE] != NULL); 409 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 410 411 __progname = obj_rtld.path; 412 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 413 environ = env; 414 main_argc = argc; 415 main_argv = argv; 416 417 trust = !issetugid(); 418 419 md_abi_variant_hook(aux_info); 420 421 fd = -1; 422 if (aux_info[AT_EXECFD] != NULL) { 423 fd = aux_info[AT_EXECFD]->a_un.a_val; 424 } else { 425 assert(aux_info[AT_PHDR] != NULL); 426 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 427 if (phdr == obj_rtld.phdr) { 428 if (!trust) { 429 _rtld_error("Tainted process refusing to run binary %s", 430 argv0); 431 rtld_die(); 432 } 433 dbg("opening main program in direct exec mode"); 434 if (argc >= 2) { 435 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 436 argv0 = argv[rtld_argc]; 437 explicit_fd = (fd != -1); 438 if (!explicit_fd) 439 fd = open_binary_fd(argv0, search_in_path); 440 if (fstat(fd, &st) == -1) { 441 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 442 explicit_fd ? "user-provided descriptor" : argv0, 443 rtld_strerror(errno)); 444 rtld_die(); 445 } 446 447 /* 448 * Rough emulation of the permission checks done by 449 * execve(2), only Unix DACs are checked, ACLs are 450 * ignored. Preserve the semantic of disabling owner 451 * to execute if owner x bit is cleared, even if 452 * others x bit is enabled. 453 * mmap(2) does not allow to mmap with PROT_EXEC if 454 * binary' file comes from noexec mount. We cannot 455 * set VV_TEXT on the binary. 456 */ 457 dir_enable = false; 458 if (st.st_uid == geteuid()) { 459 if ((st.st_mode & S_IXUSR) != 0) 460 dir_enable = true; 461 } else if (st.st_gid == getegid()) { 462 if ((st.st_mode & S_IXGRP) != 0) 463 dir_enable = true; 464 } else if ((st.st_mode & S_IXOTH) != 0) { 465 dir_enable = true; 466 } 467 if (!dir_enable) { 468 _rtld_error("No execute permission for binary %s", 469 argv0); 470 rtld_die(); 471 } 472 473 /* 474 * For direct exec mode, argv[0] is the interpreter 475 * name, we must remove it and shift arguments left 476 * before invoking binary main. Since stack layout 477 * places environment pointers and aux vectors right 478 * after the terminating NULL, we must shift 479 * environment and aux as well. 480 */ 481 main_argc = argc - rtld_argc; 482 for (i = 0; i <= main_argc; i++) 483 argv[i] = argv[i + rtld_argc]; 484 *argcp -= rtld_argc; 485 environ = env = envp = argv + main_argc + 1; 486 do { 487 *envp = *(envp + rtld_argc); 488 envp++; 489 } while (*envp != NULL); 490 aux = auxp = (Elf_Auxinfo *)envp; 491 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 492 for (;; auxp++, auxpf++) { 493 *auxp = *auxpf; 494 if (auxp->a_type == AT_NULL) 495 break; 496 } 497 } else { 498 _rtld_error("No binary"); 499 rtld_die(); 500 } 501 } 502 } 503 504 ld_bind_now = getenv(_LD("BIND_NOW")); 505 506 /* 507 * If the process is tainted, then we un-set the dangerous environment 508 * variables. The process will be marked as tainted until setuid(2) 509 * is called. If any child process calls setuid(2) we do not want any 510 * future processes to honor the potentially un-safe variables. 511 */ 512 if (!trust) { 513 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 514 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 515 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 516 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 517 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 518 _rtld_error("environment corrupt; aborting"); 519 rtld_die(); 520 } 521 } 522 ld_debug = getenv(_LD("DEBUG")); 523 if (ld_bind_now == NULL) 524 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 525 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 526 libmap_override = getenv(_LD("LIBMAP")); 527 ld_library_path = getenv(_LD("LIBRARY_PATH")); 528 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 529 ld_preload = getenv(_LD("PRELOAD")); 530 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 531 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 532 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 533 if (library_path_rpath != NULL) { 534 if (library_path_rpath[0] == 'y' || 535 library_path_rpath[0] == 'Y' || 536 library_path_rpath[0] == '1') 537 ld_library_path_rpath = true; 538 else 539 ld_library_path_rpath = false; 540 } 541 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 542 (ld_library_path != NULL) || (ld_preload != NULL) || 543 (ld_elf_hints_path != NULL) || ld_loadfltr; 544 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 545 ld_utrace = getenv(_LD("UTRACE")); 546 547 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 548 ld_elf_hints_path = ld_elf_hints_default; 549 550 if (ld_debug != NULL && *ld_debug != '\0') 551 debug = 1; 552 dbg("%s is initialized, base address = %p", __progname, 553 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 554 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 555 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 556 557 dbg("initializing thread locks"); 558 lockdflt_init(); 559 560 /* 561 * Load the main program, or process its program header if it is 562 * already loaded. 563 */ 564 if (fd != -1) { /* Load the main program. */ 565 dbg("loading main program"); 566 obj_main = map_object(fd, argv0, NULL); 567 close(fd); 568 if (obj_main == NULL) 569 rtld_die(); 570 max_stack_flags = obj_main->stack_flags; 571 } else { /* Main program already loaded. */ 572 dbg("processing main program's program header"); 573 assert(aux_info[AT_PHDR] != NULL); 574 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 575 assert(aux_info[AT_PHNUM] != NULL); 576 phnum = aux_info[AT_PHNUM]->a_un.a_val; 577 assert(aux_info[AT_PHENT] != NULL); 578 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 579 assert(aux_info[AT_ENTRY] != NULL); 580 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 581 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 582 rtld_die(); 583 } 584 585 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 586 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 587 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 588 if (kexecpath[0] == '/') 589 obj_main->path = kexecpath; 590 else if (getcwd(buf, sizeof(buf)) == NULL || 591 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 592 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 593 obj_main->path = xstrdup(argv0); 594 else 595 obj_main->path = xstrdup(buf); 596 } else { 597 dbg("No AT_EXECPATH or direct exec"); 598 obj_main->path = xstrdup(argv0); 599 } 600 dbg("obj_main path %s", obj_main->path); 601 obj_main->mainprog = true; 602 603 if (aux_info[AT_STACKPROT] != NULL && 604 aux_info[AT_STACKPROT]->a_un.a_val != 0) 605 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 606 607 #ifndef COMPAT_32BIT 608 /* 609 * Get the actual dynamic linker pathname from the executable if 610 * possible. (It should always be possible.) That ensures that 611 * gdb will find the right dynamic linker even if a non-standard 612 * one is being used. 613 */ 614 if (obj_main->interp != NULL && 615 strcmp(obj_main->interp, obj_rtld.path) != 0) { 616 free(obj_rtld.path); 617 obj_rtld.path = xstrdup(obj_main->interp); 618 __progname = obj_rtld.path; 619 } 620 #endif 621 622 digest_dynamic(obj_main, 0); 623 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 624 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 625 obj_main->dynsymcount); 626 627 linkmap_add(obj_main); 628 linkmap_add(&obj_rtld); 629 630 /* Link the main program into the list of objects. */ 631 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 632 obj_count++; 633 obj_loads++; 634 635 /* Initialize a fake symbol for resolving undefined weak references. */ 636 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 637 sym_zero.st_shndx = SHN_UNDEF; 638 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 639 640 if (!libmap_disable) 641 libmap_disable = (bool)lm_init(libmap_override); 642 643 dbg("loading LD_PRELOAD libraries"); 644 if (load_preload_objects() == -1) 645 rtld_die(); 646 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 647 648 dbg("loading needed objects"); 649 if (load_needed_objects(obj_main, 0) == -1) 650 rtld_die(); 651 652 /* Make a list of all objects loaded at startup. */ 653 last_interposer = obj_main; 654 TAILQ_FOREACH(obj, &obj_list, next) { 655 if (obj->marker) 656 continue; 657 if (obj->z_interpose && obj != obj_main) { 658 objlist_put_after(&list_main, last_interposer, obj); 659 last_interposer = obj; 660 } else { 661 objlist_push_tail(&list_main, obj); 662 } 663 obj->refcount++; 664 } 665 666 dbg("checking for required versions"); 667 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 668 rtld_die(); 669 670 if (ld_tracing) { /* We're done */ 671 trace_loaded_objects(obj_main); 672 exit(0); 673 } 674 675 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 676 dump_relocations(obj_main); 677 exit (0); 678 } 679 680 /* 681 * Processing tls relocations requires having the tls offsets 682 * initialized. Prepare offsets before starting initial 683 * relocation processing. 684 */ 685 dbg("initializing initial thread local storage offsets"); 686 STAILQ_FOREACH(entry, &list_main, link) { 687 /* 688 * Allocate all the initial objects out of the static TLS 689 * block even if they didn't ask for it. 690 */ 691 allocate_tls_offset(entry->obj); 692 } 693 694 if (relocate_objects(obj_main, 695 ld_bind_now != NULL && *ld_bind_now != '\0', 696 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 697 rtld_die(); 698 699 dbg("doing copy relocations"); 700 if (do_copy_relocations(obj_main) == -1) 701 rtld_die(); 702 703 dbg("enforcing main obj relro"); 704 if (obj_enforce_relro(obj_main) == -1) 705 rtld_die(); 706 707 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 708 dump_relocations(obj_main); 709 exit (0); 710 } 711 712 ifunc_init(aux); 713 714 /* 715 * Setup TLS for main thread. This must be done after the 716 * relocations are processed, since tls initialization section 717 * might be the subject for relocations. 718 */ 719 dbg("initializing initial thread local storage"); 720 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 721 722 dbg("initializing key program variables"); 723 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 724 set_program_var("environ", env); 725 set_program_var("__elf_aux_vector", aux); 726 727 /* Make a list of init functions to call. */ 728 objlist_init(&initlist); 729 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 730 preload_tail, &initlist); 731 732 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 733 734 map_stacks_exec(NULL); 735 736 dbg("resolving ifuncs"); 737 if (resolve_objects_ifunc(obj_main, 738 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 739 NULL) == -1) 740 rtld_die(); 741 742 if (!obj_main->crt_no_init) { 743 /* 744 * Make sure we don't call the main program's init and fini 745 * functions for binaries linked with old crt1 which calls 746 * _init itself. 747 */ 748 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 749 obj_main->preinit_array = obj_main->init_array = 750 obj_main->fini_array = (Elf_Addr)NULL; 751 } 752 753 /* 754 * Execute MD initializers required before we call the objects' 755 * init functions. 756 */ 757 pre_init(); 758 759 wlock_acquire(rtld_bind_lock, &lockstate); 760 if (obj_main->crt_no_init) 761 preinit_main(); 762 objlist_call_init(&initlist, &lockstate); 763 _r_debug_postinit(&obj_main->linkmap); 764 objlist_clear(&initlist); 765 dbg("loading filtees"); 766 TAILQ_FOREACH(obj, &obj_list, next) { 767 if (obj->marker) 768 continue; 769 if (ld_loadfltr || obj->z_loadfltr) 770 load_filtees(obj, 0, &lockstate); 771 } 772 lock_release(rtld_bind_lock, &lockstate); 773 774 dbg("transferring control to program entry point = %p", obj_main->entry); 775 776 /* Return the exit procedure and the program entry point. */ 777 *exit_proc = rtld_exit; 778 *objp = obj_main; 779 return (func_ptr_type) obj_main->entry; 780 } 781 782 void * 783 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 784 { 785 void *ptr; 786 Elf_Addr target; 787 788 ptr = (void *)make_function_pointer(def, obj); 789 target = call_ifunc_resolver(ptr); 790 return ((void *)target); 791 } 792 793 /* 794 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 795 * Changes to this function should be applied there as well. 796 */ 797 Elf_Addr 798 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 799 { 800 const Elf_Rel *rel; 801 const Elf_Sym *def; 802 const Obj_Entry *defobj; 803 Elf_Addr *where; 804 Elf_Addr target; 805 RtldLockState lockstate; 806 807 rlock_acquire(rtld_bind_lock, &lockstate); 808 if (sigsetjmp(lockstate.env, 0) != 0) 809 lock_upgrade(rtld_bind_lock, &lockstate); 810 if (obj->pltrel) 811 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 812 else 813 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 814 815 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 816 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 817 NULL, &lockstate); 818 if (def == NULL) 819 rtld_die(); 820 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 821 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 822 else 823 target = (Elf_Addr)(defobj->relocbase + def->st_value); 824 825 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 826 defobj->strtab + def->st_name, basename(obj->path), 827 (void *)target, basename(defobj->path)); 828 829 /* 830 * Write the new contents for the jmpslot. Note that depending on 831 * architecture, the value which we need to return back to the 832 * lazy binding trampoline may or may not be the target 833 * address. The value returned from reloc_jmpslot() is the value 834 * that the trampoline needs. 835 */ 836 target = reloc_jmpslot(where, target, defobj, obj, rel); 837 lock_release(rtld_bind_lock, &lockstate); 838 return target; 839 } 840 841 /* 842 * Error reporting function. Use it like printf. If formats the message 843 * into a buffer, and sets things up so that the next call to dlerror() 844 * will return the message. 845 */ 846 void 847 _rtld_error(const char *fmt, ...) 848 { 849 static char buf[512]; 850 va_list ap; 851 852 va_start(ap, fmt); 853 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 854 error_message = buf; 855 va_end(ap); 856 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 857 } 858 859 /* 860 * Return a dynamically-allocated copy of the current error message, if any. 861 */ 862 static char * 863 errmsg_save(void) 864 { 865 return error_message == NULL ? NULL : xstrdup(error_message); 866 } 867 868 /* 869 * Restore the current error message from a copy which was previously saved 870 * by errmsg_save(). The copy is freed. 871 */ 872 static void 873 errmsg_restore(char *saved_msg) 874 { 875 if (saved_msg == NULL) 876 error_message = NULL; 877 else { 878 _rtld_error("%s", saved_msg); 879 free(saved_msg); 880 } 881 } 882 883 static const char * 884 basename(const char *name) 885 { 886 const char *p = strrchr(name, '/'); 887 return p != NULL ? p + 1 : name; 888 } 889 890 static struct utsname uts; 891 892 static char * 893 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 894 const char *subst, bool may_free) 895 { 896 char *p, *p1, *res, *resp; 897 int subst_len, kw_len, subst_count, old_len, new_len; 898 899 kw_len = strlen(kw); 900 901 /* 902 * First, count the number of the keyword occurrences, to 903 * preallocate the final string. 904 */ 905 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 906 p1 = strstr(p, kw); 907 if (p1 == NULL) 908 break; 909 } 910 911 /* 912 * If the keyword is not found, just return. 913 * 914 * Return non-substituted string if resolution failed. We 915 * cannot do anything more reasonable, the failure mode of the 916 * caller is unresolved library anyway. 917 */ 918 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 919 return (may_free ? real : xstrdup(real)); 920 if (obj != NULL) 921 subst = obj->origin_path; 922 923 /* 924 * There is indeed something to substitute. Calculate the 925 * length of the resulting string, and allocate it. 926 */ 927 subst_len = strlen(subst); 928 old_len = strlen(real); 929 new_len = old_len + (subst_len - kw_len) * subst_count; 930 res = xmalloc(new_len + 1); 931 932 /* 933 * Now, execute the substitution loop. 934 */ 935 for (p = real, resp = res, *resp = '\0';;) { 936 p1 = strstr(p, kw); 937 if (p1 != NULL) { 938 /* Copy the prefix before keyword. */ 939 memcpy(resp, p, p1 - p); 940 resp += p1 - p; 941 /* Keyword replacement. */ 942 memcpy(resp, subst, subst_len); 943 resp += subst_len; 944 *resp = '\0'; 945 p = p1 + kw_len; 946 } else 947 break; 948 } 949 950 /* Copy to the end of string and finish. */ 951 strcat(resp, p); 952 if (may_free) 953 free(real); 954 return (res); 955 } 956 957 static char * 958 origin_subst(Obj_Entry *obj, const char *real) 959 { 960 char *res1, *res2, *res3, *res4; 961 962 if (obj == NULL || !trust) 963 return (xstrdup(real)); 964 if (uts.sysname[0] == '\0') { 965 if (uname(&uts) != 0) { 966 _rtld_error("utsname failed: %d", errno); 967 return (NULL); 968 } 969 } 970 /* __DECONST is safe here since without may_free real is unchanged */ 971 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 972 false); 973 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 974 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 975 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 976 return (res4); 977 } 978 979 void 980 rtld_die(void) 981 { 982 const char *msg = dlerror(); 983 984 if (msg == NULL) 985 msg = "Fatal error"; 986 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 987 rtld_fdputstr(STDERR_FILENO, msg); 988 rtld_fdputchar(STDERR_FILENO, '\n'); 989 _exit(1); 990 } 991 992 /* 993 * Process a shared object's DYNAMIC section, and save the important 994 * information in its Obj_Entry structure. 995 */ 996 static void 997 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 998 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 999 { 1000 const Elf_Dyn *dynp; 1001 Needed_Entry **needed_tail = &obj->needed; 1002 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1003 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1004 const Elf_Hashelt *hashtab; 1005 const Elf32_Word *hashval; 1006 Elf32_Word bkt, nmaskwords; 1007 int bloom_size32; 1008 int plttype = DT_REL; 1009 1010 *dyn_rpath = NULL; 1011 *dyn_soname = NULL; 1012 *dyn_runpath = NULL; 1013 1014 obj->bind_now = false; 1015 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1016 switch (dynp->d_tag) { 1017 1018 case DT_REL: 1019 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1020 break; 1021 1022 case DT_RELSZ: 1023 obj->relsize = dynp->d_un.d_val; 1024 break; 1025 1026 case DT_RELENT: 1027 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1028 break; 1029 1030 case DT_JMPREL: 1031 obj->pltrel = (const Elf_Rel *) 1032 (obj->relocbase + dynp->d_un.d_ptr); 1033 break; 1034 1035 case DT_PLTRELSZ: 1036 obj->pltrelsize = dynp->d_un.d_val; 1037 break; 1038 1039 case DT_RELA: 1040 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_RELASZ: 1044 obj->relasize = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_RELAENT: 1048 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1049 break; 1050 1051 case DT_PLTREL: 1052 plttype = dynp->d_un.d_val; 1053 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1054 break; 1055 1056 case DT_SYMTAB: 1057 obj->symtab = (const Elf_Sym *) 1058 (obj->relocbase + dynp->d_un.d_ptr); 1059 break; 1060 1061 case DT_SYMENT: 1062 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1063 break; 1064 1065 case DT_STRTAB: 1066 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1067 break; 1068 1069 case DT_STRSZ: 1070 obj->strsize = dynp->d_un.d_val; 1071 break; 1072 1073 case DT_VERNEED: 1074 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1075 dynp->d_un.d_val); 1076 break; 1077 1078 case DT_VERNEEDNUM: 1079 obj->verneednum = dynp->d_un.d_val; 1080 break; 1081 1082 case DT_VERDEF: 1083 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1084 dynp->d_un.d_val); 1085 break; 1086 1087 case DT_VERDEFNUM: 1088 obj->verdefnum = dynp->d_un.d_val; 1089 break; 1090 1091 case DT_VERSYM: 1092 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1093 dynp->d_un.d_val); 1094 break; 1095 1096 case DT_HASH: 1097 { 1098 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1099 dynp->d_un.d_ptr); 1100 obj->nbuckets = hashtab[0]; 1101 obj->nchains = hashtab[1]; 1102 obj->buckets = hashtab + 2; 1103 obj->chains = obj->buckets + obj->nbuckets; 1104 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1105 obj->buckets != NULL; 1106 } 1107 break; 1108 1109 case DT_GNU_HASH: 1110 { 1111 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1112 dynp->d_un.d_ptr); 1113 obj->nbuckets_gnu = hashtab[0]; 1114 obj->symndx_gnu = hashtab[1]; 1115 nmaskwords = hashtab[2]; 1116 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1117 obj->maskwords_bm_gnu = nmaskwords - 1; 1118 obj->shift2_gnu = hashtab[3]; 1119 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1120 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1121 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1122 obj->symndx_gnu; 1123 /* Number of bitmask words is required to be power of 2 */ 1124 obj->valid_hash_gnu = powerof2(nmaskwords) && 1125 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1126 } 1127 break; 1128 1129 case DT_NEEDED: 1130 if (!obj->rtld) { 1131 Needed_Entry *nep = NEW(Needed_Entry); 1132 nep->name = dynp->d_un.d_val; 1133 nep->obj = NULL; 1134 nep->next = NULL; 1135 1136 *needed_tail = nep; 1137 needed_tail = &nep->next; 1138 } 1139 break; 1140 1141 case DT_FILTER: 1142 if (!obj->rtld) { 1143 Needed_Entry *nep = NEW(Needed_Entry); 1144 nep->name = dynp->d_un.d_val; 1145 nep->obj = NULL; 1146 nep->next = NULL; 1147 1148 *needed_filtees_tail = nep; 1149 needed_filtees_tail = &nep->next; 1150 } 1151 break; 1152 1153 case DT_AUXILIARY: 1154 if (!obj->rtld) { 1155 Needed_Entry *nep = NEW(Needed_Entry); 1156 nep->name = dynp->d_un.d_val; 1157 nep->obj = NULL; 1158 nep->next = NULL; 1159 1160 *needed_aux_filtees_tail = nep; 1161 needed_aux_filtees_tail = &nep->next; 1162 } 1163 break; 1164 1165 case DT_PLTGOT: 1166 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1167 break; 1168 1169 case DT_TEXTREL: 1170 obj->textrel = true; 1171 break; 1172 1173 case DT_SYMBOLIC: 1174 obj->symbolic = true; 1175 break; 1176 1177 case DT_RPATH: 1178 /* 1179 * We have to wait until later to process this, because we 1180 * might not have gotten the address of the string table yet. 1181 */ 1182 *dyn_rpath = dynp; 1183 break; 1184 1185 case DT_SONAME: 1186 *dyn_soname = dynp; 1187 break; 1188 1189 case DT_RUNPATH: 1190 *dyn_runpath = dynp; 1191 break; 1192 1193 case DT_INIT: 1194 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1195 break; 1196 1197 case DT_PREINIT_ARRAY: 1198 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1199 break; 1200 1201 case DT_PREINIT_ARRAYSZ: 1202 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1203 break; 1204 1205 case DT_INIT_ARRAY: 1206 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1207 break; 1208 1209 case DT_INIT_ARRAYSZ: 1210 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1211 break; 1212 1213 case DT_FINI: 1214 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1215 break; 1216 1217 case DT_FINI_ARRAY: 1218 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1219 break; 1220 1221 case DT_FINI_ARRAYSZ: 1222 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1223 break; 1224 1225 /* 1226 * Don't process DT_DEBUG on MIPS as the dynamic section 1227 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1228 */ 1229 1230 #ifndef __mips__ 1231 case DT_DEBUG: 1232 if (!early) 1233 dbg("Filling in DT_DEBUG entry"); 1234 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1235 break; 1236 #endif 1237 1238 case DT_FLAGS: 1239 if (dynp->d_un.d_val & DF_ORIGIN) 1240 obj->z_origin = true; 1241 if (dynp->d_un.d_val & DF_SYMBOLIC) 1242 obj->symbolic = true; 1243 if (dynp->d_un.d_val & DF_TEXTREL) 1244 obj->textrel = true; 1245 if (dynp->d_un.d_val & DF_BIND_NOW) 1246 obj->bind_now = true; 1247 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1248 ;*/ 1249 break; 1250 #ifdef __mips__ 1251 case DT_MIPS_LOCAL_GOTNO: 1252 obj->local_gotno = dynp->d_un.d_val; 1253 break; 1254 1255 case DT_MIPS_SYMTABNO: 1256 obj->symtabno = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_MIPS_GOTSYM: 1260 obj->gotsym = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_RLD_MAP: 1264 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1265 break; 1266 1267 case DT_MIPS_PLTGOT: 1268 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1269 dynp->d_un.d_ptr); 1270 break; 1271 1272 #endif 1273 1274 #ifdef __powerpc64__ 1275 case DT_PPC64_GLINK: 1276 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1277 break; 1278 #endif 1279 1280 case DT_FLAGS_1: 1281 if (dynp->d_un.d_val & DF_1_NOOPEN) 1282 obj->z_noopen = true; 1283 if (dynp->d_un.d_val & DF_1_ORIGIN) 1284 obj->z_origin = true; 1285 if (dynp->d_un.d_val & DF_1_GLOBAL) 1286 obj->z_global = true; 1287 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1288 obj->bind_now = true; 1289 if (dynp->d_un.d_val & DF_1_NODELETE) 1290 obj->z_nodelete = true; 1291 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1292 obj->z_loadfltr = true; 1293 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1294 obj->z_interpose = true; 1295 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1296 obj->z_nodeflib = true; 1297 break; 1298 1299 default: 1300 if (!early) { 1301 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1302 (long)dynp->d_tag); 1303 } 1304 break; 1305 } 1306 } 1307 1308 obj->traced = false; 1309 1310 if (plttype == DT_RELA) { 1311 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1312 obj->pltrel = NULL; 1313 obj->pltrelasize = obj->pltrelsize; 1314 obj->pltrelsize = 0; 1315 } 1316 1317 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1318 if (obj->valid_hash_sysv) 1319 obj->dynsymcount = obj->nchains; 1320 else if (obj->valid_hash_gnu) { 1321 obj->dynsymcount = 0; 1322 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1323 if (obj->buckets_gnu[bkt] == 0) 1324 continue; 1325 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1326 do 1327 obj->dynsymcount++; 1328 while ((*hashval++ & 1u) == 0); 1329 } 1330 obj->dynsymcount += obj->symndx_gnu; 1331 } 1332 } 1333 1334 static bool 1335 obj_resolve_origin(Obj_Entry *obj) 1336 { 1337 1338 if (obj->origin_path != NULL) 1339 return (true); 1340 obj->origin_path = xmalloc(PATH_MAX); 1341 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1342 } 1343 1344 static void 1345 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1346 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1347 { 1348 1349 if (obj->z_origin && !obj_resolve_origin(obj)) 1350 rtld_die(); 1351 1352 if (dyn_runpath != NULL) { 1353 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1354 obj->runpath = origin_subst(obj, obj->runpath); 1355 } else if (dyn_rpath != NULL) { 1356 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1357 obj->rpath = origin_subst(obj, obj->rpath); 1358 } 1359 if (dyn_soname != NULL) 1360 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1361 } 1362 1363 static void 1364 digest_dynamic(Obj_Entry *obj, int early) 1365 { 1366 const Elf_Dyn *dyn_rpath; 1367 const Elf_Dyn *dyn_soname; 1368 const Elf_Dyn *dyn_runpath; 1369 1370 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1371 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1372 } 1373 1374 /* 1375 * Process a shared object's program header. This is used only for the 1376 * main program, when the kernel has already loaded the main program 1377 * into memory before calling the dynamic linker. It creates and 1378 * returns an Obj_Entry structure. 1379 */ 1380 static Obj_Entry * 1381 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1382 { 1383 Obj_Entry *obj; 1384 const Elf_Phdr *phlimit = phdr + phnum; 1385 const Elf_Phdr *ph; 1386 Elf_Addr note_start, note_end; 1387 int nsegs = 0; 1388 1389 obj = obj_new(); 1390 for (ph = phdr; ph < phlimit; ph++) { 1391 if (ph->p_type != PT_PHDR) 1392 continue; 1393 1394 obj->phdr = phdr; 1395 obj->phsize = ph->p_memsz; 1396 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1397 break; 1398 } 1399 1400 obj->stack_flags = PF_X | PF_R | PF_W; 1401 1402 for (ph = phdr; ph < phlimit; ph++) { 1403 switch (ph->p_type) { 1404 1405 case PT_INTERP: 1406 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1407 break; 1408 1409 case PT_LOAD: 1410 if (nsegs == 0) { /* First load segment */ 1411 obj->vaddrbase = trunc_page(ph->p_vaddr); 1412 obj->mapbase = obj->vaddrbase + obj->relocbase; 1413 } else { /* Last load segment */ 1414 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1415 obj->vaddrbase; 1416 } 1417 nsegs++; 1418 if ((ph->p_flags & PF_X) == PF_X) { 1419 obj->textsize = MAX(obj->textsize, 1420 round_page(ph->p_vaddr + ph->p_memsz) - obj->vaddrbase); 1421 } 1422 break; 1423 1424 case PT_DYNAMIC: 1425 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1426 break; 1427 1428 case PT_TLS: 1429 obj->tlsindex = 1; 1430 obj->tlssize = ph->p_memsz; 1431 obj->tlsalign = ph->p_align; 1432 obj->tlsinitsize = ph->p_filesz; 1433 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1434 break; 1435 1436 case PT_GNU_STACK: 1437 obj->stack_flags = ph->p_flags; 1438 break; 1439 1440 case PT_GNU_RELRO: 1441 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1442 obj->relro_size = round_page(ph->p_memsz); 1443 break; 1444 1445 case PT_NOTE: 1446 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1447 note_end = note_start + ph->p_filesz; 1448 digest_notes(obj, note_start, note_end); 1449 break; 1450 } 1451 } 1452 if (nsegs < 1) { 1453 _rtld_error("%s: too few PT_LOAD segments", path); 1454 return NULL; 1455 } 1456 1457 obj->entry = entry; 1458 return obj; 1459 } 1460 1461 void 1462 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1463 { 1464 const Elf_Note *note; 1465 const char *note_name; 1466 uintptr_t p; 1467 1468 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1469 note = (const Elf_Note *)((const char *)(note + 1) + 1470 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1471 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1472 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1473 note->n_descsz != sizeof(int32_t)) 1474 continue; 1475 if (note->n_type != NT_FREEBSD_ABI_TAG && 1476 note->n_type != NT_FREEBSD_NOINIT_TAG) 1477 continue; 1478 note_name = (const char *)(note + 1); 1479 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1480 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1481 continue; 1482 switch (note->n_type) { 1483 case NT_FREEBSD_ABI_TAG: 1484 /* FreeBSD osrel note */ 1485 p = (uintptr_t)(note + 1); 1486 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1487 obj->osrel = *(const int32_t *)(p); 1488 dbg("note osrel %d", obj->osrel); 1489 break; 1490 case NT_FREEBSD_NOINIT_TAG: 1491 /* FreeBSD 'crt does not call init' note */ 1492 obj->crt_no_init = true; 1493 dbg("note crt_no_init"); 1494 break; 1495 } 1496 } 1497 } 1498 1499 static Obj_Entry * 1500 dlcheck(void *handle) 1501 { 1502 Obj_Entry *obj; 1503 1504 TAILQ_FOREACH(obj, &obj_list, next) { 1505 if (obj == (Obj_Entry *) handle) 1506 break; 1507 } 1508 1509 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1510 _rtld_error("Invalid shared object handle %p", handle); 1511 return NULL; 1512 } 1513 return obj; 1514 } 1515 1516 /* 1517 * If the given object is already in the donelist, return true. Otherwise 1518 * add the object to the list and return false. 1519 */ 1520 static bool 1521 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1522 { 1523 unsigned int i; 1524 1525 for (i = 0; i < dlp->num_used; i++) 1526 if (dlp->objs[i] == obj) 1527 return true; 1528 /* 1529 * Our donelist allocation should always be sufficient. But if 1530 * our threads locking isn't working properly, more shared objects 1531 * could have been loaded since we allocated the list. That should 1532 * never happen, but we'll handle it properly just in case it does. 1533 */ 1534 if (dlp->num_used < dlp->num_alloc) 1535 dlp->objs[dlp->num_used++] = obj; 1536 return false; 1537 } 1538 1539 /* 1540 * Hash function for symbol table lookup. Don't even think about changing 1541 * this. It is specified by the System V ABI. 1542 */ 1543 unsigned long 1544 elf_hash(const char *name) 1545 { 1546 const unsigned char *p = (const unsigned char *) name; 1547 unsigned long h = 0; 1548 unsigned long g; 1549 1550 while (*p != '\0') { 1551 h = (h << 4) + *p++; 1552 if ((g = h & 0xf0000000) != 0) 1553 h ^= g >> 24; 1554 h &= ~g; 1555 } 1556 return h; 1557 } 1558 1559 /* 1560 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1561 * unsigned in case it's implemented with a wider type. 1562 */ 1563 static uint32_t 1564 gnu_hash(const char *s) 1565 { 1566 uint32_t h; 1567 unsigned char c; 1568 1569 h = 5381; 1570 for (c = *s; c != '\0'; c = *++s) 1571 h = h * 33 + c; 1572 return (h & 0xffffffff); 1573 } 1574 1575 1576 /* 1577 * Find the library with the given name, and return its full pathname. 1578 * The returned string is dynamically allocated. Generates an error 1579 * message and returns NULL if the library cannot be found. 1580 * 1581 * If the second argument is non-NULL, then it refers to an already- 1582 * loaded shared object, whose library search path will be searched. 1583 * 1584 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1585 * descriptor (which is close-on-exec) will be passed out via the third 1586 * argument. 1587 * 1588 * The search order is: 1589 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1590 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1591 * LD_LIBRARY_PATH 1592 * DT_RUNPATH in the referencing file 1593 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1594 * from list) 1595 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1596 * 1597 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1598 */ 1599 static char * 1600 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1601 { 1602 char *pathname, *refobj_path; 1603 const char *name; 1604 bool nodeflib, objgiven; 1605 1606 objgiven = refobj != NULL; 1607 1608 if (libmap_disable || !objgiven || 1609 (name = lm_find(refobj->path, xname)) == NULL) 1610 name = xname; 1611 1612 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1613 if (name[0] != '/' && !trust) { 1614 _rtld_error("Absolute pathname required " 1615 "for shared object \"%s\"", name); 1616 return (NULL); 1617 } 1618 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1619 __DECONST(char *, name))); 1620 } 1621 1622 dbg(" Searching for \"%s\"", name); 1623 refobj_path = objgiven ? refobj->path : NULL; 1624 1625 /* 1626 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1627 * back to pre-conforming behaviour if user requested so with 1628 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1629 * nodeflib. 1630 */ 1631 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1632 pathname = search_library_path(name, ld_library_path, 1633 refobj_path, fdp); 1634 if (pathname != NULL) 1635 return (pathname); 1636 if (refobj != NULL) { 1637 pathname = search_library_path(name, refobj->rpath, 1638 refobj_path, fdp); 1639 if (pathname != NULL) 1640 return (pathname); 1641 } 1642 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1643 if (pathname != NULL) 1644 return (pathname); 1645 pathname = search_library_path(name, gethints(false), 1646 refobj_path, fdp); 1647 if (pathname != NULL) 1648 return (pathname); 1649 pathname = search_library_path(name, ld_standard_library_path, 1650 refobj_path, fdp); 1651 if (pathname != NULL) 1652 return (pathname); 1653 } else { 1654 nodeflib = objgiven ? refobj->z_nodeflib : false; 1655 if (objgiven) { 1656 pathname = search_library_path(name, refobj->rpath, 1657 refobj->path, fdp); 1658 if (pathname != NULL) 1659 return (pathname); 1660 } 1661 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1662 pathname = search_library_path(name, obj_main->rpath, 1663 refobj_path, fdp); 1664 if (pathname != NULL) 1665 return (pathname); 1666 } 1667 pathname = search_library_path(name, ld_library_path, 1668 refobj_path, fdp); 1669 if (pathname != NULL) 1670 return (pathname); 1671 if (objgiven) { 1672 pathname = search_library_path(name, refobj->runpath, 1673 refobj_path, fdp); 1674 if (pathname != NULL) 1675 return (pathname); 1676 } 1677 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1678 if (pathname != NULL) 1679 return (pathname); 1680 pathname = search_library_path(name, gethints(nodeflib), 1681 refobj_path, fdp); 1682 if (pathname != NULL) 1683 return (pathname); 1684 if (objgiven && !nodeflib) { 1685 pathname = search_library_path(name, 1686 ld_standard_library_path, refobj_path, fdp); 1687 if (pathname != NULL) 1688 return (pathname); 1689 } 1690 } 1691 1692 if (objgiven && refobj->path != NULL) { 1693 _rtld_error("Shared object \"%s\" not found, " 1694 "required by \"%s\"", name, basename(refobj->path)); 1695 } else { 1696 _rtld_error("Shared object \"%s\" not found", name); 1697 } 1698 return (NULL); 1699 } 1700 1701 /* 1702 * Given a symbol number in a referencing object, find the corresponding 1703 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1704 * no definition was found. Returns a pointer to the Obj_Entry of the 1705 * defining object via the reference parameter DEFOBJ_OUT. 1706 */ 1707 const Elf_Sym * 1708 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1709 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1710 RtldLockState *lockstate) 1711 { 1712 const Elf_Sym *ref; 1713 const Elf_Sym *def; 1714 const Obj_Entry *defobj; 1715 const Ver_Entry *ve; 1716 SymLook req; 1717 const char *name; 1718 int res; 1719 1720 /* 1721 * If we have already found this symbol, get the information from 1722 * the cache. 1723 */ 1724 if (symnum >= refobj->dynsymcount) 1725 return NULL; /* Bad object */ 1726 if (cache != NULL && cache[symnum].sym != NULL) { 1727 *defobj_out = cache[symnum].obj; 1728 return cache[symnum].sym; 1729 } 1730 1731 ref = refobj->symtab + symnum; 1732 name = refobj->strtab + ref->st_name; 1733 def = NULL; 1734 defobj = NULL; 1735 ve = NULL; 1736 1737 /* 1738 * We don't have to do a full scale lookup if the symbol is local. 1739 * We know it will bind to the instance in this load module; to 1740 * which we already have a pointer (ie ref). By not doing a lookup, 1741 * we not only improve performance, but it also avoids unresolvable 1742 * symbols when local symbols are not in the hash table. This has 1743 * been seen with the ia64 toolchain. 1744 */ 1745 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1746 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1747 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1748 symnum); 1749 } 1750 symlook_init(&req, name); 1751 req.flags = flags; 1752 ve = req.ventry = fetch_ventry(refobj, symnum); 1753 req.lockstate = lockstate; 1754 res = symlook_default(&req, refobj); 1755 if (res == 0) { 1756 def = req.sym_out; 1757 defobj = req.defobj_out; 1758 } 1759 } else { 1760 def = ref; 1761 defobj = refobj; 1762 } 1763 1764 /* 1765 * If we found no definition and the reference is weak, treat the 1766 * symbol as having the value zero. 1767 */ 1768 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1769 def = &sym_zero; 1770 defobj = obj_main; 1771 } 1772 1773 if (def != NULL) { 1774 *defobj_out = defobj; 1775 /* Record the information in the cache to avoid subsequent lookups. */ 1776 if (cache != NULL) { 1777 cache[symnum].sym = def; 1778 cache[symnum].obj = defobj; 1779 } 1780 } else { 1781 if (refobj != &obj_rtld) 1782 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1783 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1784 } 1785 return def; 1786 } 1787 1788 /* 1789 * Return the search path from the ldconfig hints file, reading it if 1790 * necessary. If nostdlib is true, then the default search paths are 1791 * not added to result. 1792 * 1793 * Returns NULL if there are problems with the hints file, 1794 * or if the search path there is empty. 1795 */ 1796 static const char * 1797 gethints(bool nostdlib) 1798 { 1799 static char *filtered_path; 1800 static const char *hints; 1801 static struct elfhints_hdr hdr; 1802 struct fill_search_info_args sargs, hargs; 1803 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1804 struct dl_serpath *SLPpath, *hintpath; 1805 char *p; 1806 struct stat hint_stat; 1807 unsigned int SLPndx, hintndx, fndx, fcount; 1808 int fd; 1809 size_t flen; 1810 uint32_t dl; 1811 bool skip; 1812 1813 /* First call, read the hints file */ 1814 if (hints == NULL) { 1815 /* Keep from trying again in case the hints file is bad. */ 1816 hints = ""; 1817 1818 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1819 return (NULL); 1820 1821 /* 1822 * Check of hdr.dirlistlen value against type limit 1823 * intends to pacify static analyzers. Further 1824 * paranoia leads to checks that dirlist is fully 1825 * contained in the file range. 1826 */ 1827 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1828 hdr.magic != ELFHINTS_MAGIC || 1829 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1830 fstat(fd, &hint_stat) == -1) { 1831 cleanup1: 1832 close(fd); 1833 hdr.dirlistlen = 0; 1834 return (NULL); 1835 } 1836 dl = hdr.strtab; 1837 if (dl + hdr.dirlist < dl) 1838 goto cleanup1; 1839 dl += hdr.dirlist; 1840 if (dl + hdr.dirlistlen < dl) 1841 goto cleanup1; 1842 dl += hdr.dirlistlen; 1843 if (dl > hint_stat.st_size) 1844 goto cleanup1; 1845 p = xmalloc(hdr.dirlistlen + 1); 1846 if (pread(fd, p, hdr.dirlistlen + 1, 1847 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1848 p[hdr.dirlistlen] != '\0') { 1849 free(p); 1850 goto cleanup1; 1851 } 1852 hints = p; 1853 close(fd); 1854 } 1855 1856 /* 1857 * If caller agreed to receive list which includes the default 1858 * paths, we are done. Otherwise, if we still did not 1859 * calculated filtered result, do it now. 1860 */ 1861 if (!nostdlib) 1862 return (hints[0] != '\0' ? hints : NULL); 1863 if (filtered_path != NULL) 1864 goto filt_ret; 1865 1866 /* 1867 * Obtain the list of all configured search paths, and the 1868 * list of the default paths. 1869 * 1870 * First estimate the size of the results. 1871 */ 1872 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1873 smeta.dls_cnt = 0; 1874 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1875 hmeta.dls_cnt = 0; 1876 1877 sargs.request = RTLD_DI_SERINFOSIZE; 1878 sargs.serinfo = &smeta; 1879 hargs.request = RTLD_DI_SERINFOSIZE; 1880 hargs.serinfo = &hmeta; 1881 1882 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1883 &sargs); 1884 path_enumerate(hints, fill_search_info, NULL, &hargs); 1885 1886 SLPinfo = xmalloc(smeta.dls_size); 1887 hintinfo = xmalloc(hmeta.dls_size); 1888 1889 /* 1890 * Next fetch both sets of paths. 1891 */ 1892 sargs.request = RTLD_DI_SERINFO; 1893 sargs.serinfo = SLPinfo; 1894 sargs.serpath = &SLPinfo->dls_serpath[0]; 1895 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1896 1897 hargs.request = RTLD_DI_SERINFO; 1898 hargs.serinfo = hintinfo; 1899 hargs.serpath = &hintinfo->dls_serpath[0]; 1900 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1901 1902 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1903 &sargs); 1904 path_enumerate(hints, fill_search_info, NULL, &hargs); 1905 1906 /* 1907 * Now calculate the difference between two sets, by excluding 1908 * standard paths from the full set. 1909 */ 1910 fndx = 0; 1911 fcount = 0; 1912 filtered_path = xmalloc(hdr.dirlistlen + 1); 1913 hintpath = &hintinfo->dls_serpath[0]; 1914 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1915 skip = false; 1916 SLPpath = &SLPinfo->dls_serpath[0]; 1917 /* 1918 * Check each standard path against current. 1919 */ 1920 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1921 /* matched, skip the path */ 1922 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1923 skip = true; 1924 break; 1925 } 1926 } 1927 if (skip) 1928 continue; 1929 /* 1930 * Not matched against any standard path, add the path 1931 * to result. Separate consequtive paths with ':'. 1932 */ 1933 if (fcount > 0) { 1934 filtered_path[fndx] = ':'; 1935 fndx++; 1936 } 1937 fcount++; 1938 flen = strlen(hintpath->dls_name); 1939 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1940 fndx += flen; 1941 } 1942 filtered_path[fndx] = '\0'; 1943 1944 free(SLPinfo); 1945 free(hintinfo); 1946 1947 filt_ret: 1948 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1949 } 1950 1951 static void 1952 init_dag(Obj_Entry *root) 1953 { 1954 const Needed_Entry *needed; 1955 const Objlist_Entry *elm; 1956 DoneList donelist; 1957 1958 if (root->dag_inited) 1959 return; 1960 donelist_init(&donelist); 1961 1962 /* Root object belongs to own DAG. */ 1963 objlist_push_tail(&root->dldags, root); 1964 objlist_push_tail(&root->dagmembers, root); 1965 donelist_check(&donelist, root); 1966 1967 /* 1968 * Add dependencies of root object to DAG in breadth order 1969 * by exploiting the fact that each new object get added 1970 * to the tail of the dagmembers list. 1971 */ 1972 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1973 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1974 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1975 continue; 1976 objlist_push_tail(&needed->obj->dldags, root); 1977 objlist_push_tail(&root->dagmembers, needed->obj); 1978 } 1979 } 1980 root->dag_inited = true; 1981 } 1982 1983 static void 1984 init_marker(Obj_Entry *marker) 1985 { 1986 1987 bzero(marker, sizeof(*marker)); 1988 marker->marker = true; 1989 } 1990 1991 Obj_Entry * 1992 globallist_curr(const Obj_Entry *obj) 1993 { 1994 1995 for (;;) { 1996 if (obj == NULL) 1997 return (NULL); 1998 if (!obj->marker) 1999 return (__DECONST(Obj_Entry *, obj)); 2000 obj = TAILQ_PREV(obj, obj_entry_q, next); 2001 } 2002 } 2003 2004 Obj_Entry * 2005 globallist_next(const Obj_Entry *obj) 2006 { 2007 2008 for (;;) { 2009 obj = TAILQ_NEXT(obj, next); 2010 if (obj == NULL) 2011 return (NULL); 2012 if (!obj->marker) 2013 return (__DECONST(Obj_Entry *, obj)); 2014 } 2015 } 2016 2017 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2018 static void 2019 hold_object(Obj_Entry *obj) 2020 { 2021 2022 obj->holdcount++; 2023 } 2024 2025 static void 2026 unhold_object(Obj_Entry *obj) 2027 { 2028 2029 assert(obj->holdcount > 0); 2030 if (--obj->holdcount == 0 && obj->unholdfree) 2031 release_object(obj); 2032 } 2033 2034 static void 2035 process_z(Obj_Entry *root) 2036 { 2037 const Objlist_Entry *elm; 2038 Obj_Entry *obj; 2039 2040 /* 2041 * Walk over object DAG and process every dependent object 2042 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2043 * to grow their own DAG. 2044 * 2045 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2046 * symlook_global() to work. 2047 * 2048 * For DF_1_NODELETE, the DAG should have its reference upped. 2049 */ 2050 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2051 obj = elm->obj; 2052 if (obj == NULL) 2053 continue; 2054 if (obj->z_nodelete && !obj->ref_nodel) { 2055 dbg("obj %s -z nodelete", obj->path); 2056 init_dag(obj); 2057 ref_dag(obj); 2058 obj->ref_nodel = true; 2059 } 2060 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2061 dbg("obj %s -z global", obj->path); 2062 objlist_push_tail(&list_global, obj); 2063 init_dag(obj); 2064 } 2065 } 2066 } 2067 /* 2068 * Initialize the dynamic linker. The argument is the address at which 2069 * the dynamic linker has been mapped into memory. The primary task of 2070 * this function is to relocate the dynamic linker. 2071 */ 2072 static void 2073 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2074 { 2075 Obj_Entry objtmp; /* Temporary rtld object */ 2076 const Elf_Ehdr *ehdr; 2077 const Elf_Dyn *dyn_rpath; 2078 const Elf_Dyn *dyn_soname; 2079 const Elf_Dyn *dyn_runpath; 2080 2081 #ifdef RTLD_INIT_PAGESIZES_EARLY 2082 /* The page size is required by the dynamic memory allocator. */ 2083 init_pagesizes(aux_info); 2084 #endif 2085 2086 /* 2087 * Conjure up an Obj_Entry structure for the dynamic linker. 2088 * 2089 * The "path" member can't be initialized yet because string constants 2090 * cannot yet be accessed. Below we will set it correctly. 2091 */ 2092 memset(&objtmp, 0, sizeof(objtmp)); 2093 objtmp.path = NULL; 2094 objtmp.rtld = true; 2095 objtmp.mapbase = mapbase; 2096 #ifdef PIC 2097 objtmp.relocbase = mapbase; 2098 #endif 2099 2100 objtmp.dynamic = rtld_dynamic(&objtmp); 2101 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2102 assert(objtmp.needed == NULL); 2103 #if !defined(__mips__) 2104 /* MIPS has a bogus DT_TEXTREL. */ 2105 assert(!objtmp.textrel); 2106 #endif 2107 /* 2108 * Temporarily put the dynamic linker entry into the object list, so 2109 * that symbols can be found. 2110 */ 2111 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2112 2113 ehdr = (Elf_Ehdr *)mapbase; 2114 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2115 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2116 2117 /* Initialize the object list. */ 2118 TAILQ_INIT(&obj_list); 2119 2120 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2121 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2122 2123 #ifndef RTLD_INIT_PAGESIZES_EARLY 2124 /* The page size is required by the dynamic memory allocator. */ 2125 init_pagesizes(aux_info); 2126 #endif 2127 2128 if (aux_info[AT_OSRELDATE] != NULL) 2129 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2130 2131 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2132 2133 /* Replace the path with a dynamically allocated copy. */ 2134 obj_rtld.path = xstrdup(ld_path_rtld); 2135 2136 r_debug.r_brk = r_debug_state; 2137 r_debug.r_state = RT_CONSISTENT; 2138 } 2139 2140 /* 2141 * Retrieve the array of supported page sizes. The kernel provides the page 2142 * sizes in increasing order. 2143 */ 2144 static void 2145 init_pagesizes(Elf_Auxinfo **aux_info) 2146 { 2147 static size_t psa[MAXPAGESIZES]; 2148 int mib[2]; 2149 size_t len, size; 2150 2151 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2152 NULL) { 2153 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2154 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2155 } else { 2156 len = 2; 2157 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2158 size = sizeof(psa); 2159 else { 2160 /* As a fallback, retrieve the base page size. */ 2161 size = sizeof(psa[0]); 2162 if (aux_info[AT_PAGESZ] != NULL) { 2163 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2164 goto psa_filled; 2165 } else { 2166 mib[0] = CTL_HW; 2167 mib[1] = HW_PAGESIZE; 2168 len = 2; 2169 } 2170 } 2171 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2172 _rtld_error("sysctl for hw.pagesize(s) failed"); 2173 rtld_die(); 2174 } 2175 psa_filled: 2176 pagesizes = psa; 2177 } 2178 npagesizes = size / sizeof(pagesizes[0]); 2179 /* Discard any invalid entries at the end of the array. */ 2180 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2181 npagesizes--; 2182 } 2183 2184 /* 2185 * Add the init functions from a needed object list (and its recursive 2186 * needed objects) to "list". This is not used directly; it is a helper 2187 * function for initlist_add_objects(). The write lock must be held 2188 * when this function is called. 2189 */ 2190 static void 2191 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2192 { 2193 /* Recursively process the successor needed objects. */ 2194 if (needed->next != NULL) 2195 initlist_add_neededs(needed->next, list); 2196 2197 /* Process the current needed object. */ 2198 if (needed->obj != NULL) 2199 initlist_add_objects(needed->obj, needed->obj, list); 2200 } 2201 2202 /* 2203 * Scan all of the DAGs rooted in the range of objects from "obj" to 2204 * "tail" and add their init functions to "list". This recurses over 2205 * the DAGs and ensure the proper init ordering such that each object's 2206 * needed libraries are initialized before the object itself. At the 2207 * same time, this function adds the objects to the global finalization 2208 * list "list_fini" in the opposite order. The write lock must be 2209 * held when this function is called. 2210 */ 2211 static void 2212 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2213 { 2214 Obj_Entry *nobj; 2215 2216 if (obj->init_scanned || obj->init_done) 2217 return; 2218 obj->init_scanned = true; 2219 2220 /* Recursively process the successor objects. */ 2221 nobj = globallist_next(obj); 2222 if (nobj != NULL && obj != tail) 2223 initlist_add_objects(nobj, tail, list); 2224 2225 /* Recursively process the needed objects. */ 2226 if (obj->needed != NULL) 2227 initlist_add_neededs(obj->needed, list); 2228 if (obj->needed_filtees != NULL) 2229 initlist_add_neededs(obj->needed_filtees, list); 2230 if (obj->needed_aux_filtees != NULL) 2231 initlist_add_neededs(obj->needed_aux_filtees, list); 2232 2233 /* Add the object to the init list. */ 2234 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2235 obj->init_array != (Elf_Addr)NULL) 2236 objlist_push_tail(list, obj); 2237 2238 /* Add the object to the global fini list in the reverse order. */ 2239 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2240 && !obj->on_fini_list) { 2241 objlist_push_head(&list_fini, obj); 2242 obj->on_fini_list = true; 2243 } 2244 } 2245 2246 #ifndef FPTR_TARGET 2247 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2248 #endif 2249 2250 static void 2251 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2252 { 2253 Needed_Entry *needed, *needed1; 2254 2255 for (needed = n; needed != NULL; needed = needed->next) { 2256 if (needed->obj != NULL) { 2257 dlclose_locked(needed->obj, lockstate); 2258 needed->obj = NULL; 2259 } 2260 } 2261 for (needed = n; needed != NULL; needed = needed1) { 2262 needed1 = needed->next; 2263 free(needed); 2264 } 2265 } 2266 2267 static void 2268 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2269 { 2270 2271 free_needed_filtees(obj->needed_filtees, lockstate); 2272 obj->needed_filtees = NULL; 2273 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2274 obj->needed_aux_filtees = NULL; 2275 obj->filtees_loaded = false; 2276 } 2277 2278 static void 2279 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2280 RtldLockState *lockstate) 2281 { 2282 2283 for (; needed != NULL; needed = needed->next) { 2284 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2285 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2286 RTLD_LOCAL, lockstate); 2287 } 2288 } 2289 2290 static void 2291 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2292 { 2293 2294 lock_restart_for_upgrade(lockstate); 2295 if (!obj->filtees_loaded) { 2296 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2297 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2298 obj->filtees_loaded = true; 2299 } 2300 } 2301 2302 static int 2303 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2304 { 2305 Obj_Entry *obj1; 2306 2307 for (; needed != NULL; needed = needed->next) { 2308 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2309 flags & ~RTLD_LO_NOLOAD); 2310 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2311 return (-1); 2312 } 2313 return (0); 2314 } 2315 2316 /* 2317 * Given a shared object, traverse its list of needed objects, and load 2318 * each of them. Returns 0 on success. Generates an error message and 2319 * returns -1 on failure. 2320 */ 2321 static int 2322 load_needed_objects(Obj_Entry *first, int flags) 2323 { 2324 Obj_Entry *obj; 2325 2326 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2327 if (obj->marker) 2328 continue; 2329 if (process_needed(obj, obj->needed, flags) == -1) 2330 return (-1); 2331 } 2332 return (0); 2333 } 2334 2335 static int 2336 load_preload_objects(void) 2337 { 2338 char *p = ld_preload; 2339 Obj_Entry *obj; 2340 static const char delim[] = " \t:;"; 2341 2342 if (p == NULL) 2343 return 0; 2344 2345 p += strspn(p, delim); 2346 while (*p != '\0') { 2347 size_t len = strcspn(p, delim); 2348 char savech; 2349 2350 savech = p[len]; 2351 p[len] = '\0'; 2352 obj = load_object(p, -1, NULL, 0); 2353 if (obj == NULL) 2354 return -1; /* XXX - cleanup */ 2355 obj->z_interpose = true; 2356 p[len] = savech; 2357 p += len; 2358 p += strspn(p, delim); 2359 } 2360 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2361 return 0; 2362 } 2363 2364 static const char * 2365 printable_path(const char *path) 2366 { 2367 2368 return (path == NULL ? "<unknown>" : path); 2369 } 2370 2371 /* 2372 * Load a shared object into memory, if it is not already loaded. The 2373 * object may be specified by name or by user-supplied file descriptor 2374 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2375 * duplicate is. 2376 * 2377 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2378 * on failure. 2379 */ 2380 static Obj_Entry * 2381 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2382 { 2383 Obj_Entry *obj; 2384 int fd; 2385 struct stat sb; 2386 char *path; 2387 2388 fd = -1; 2389 if (name != NULL) { 2390 TAILQ_FOREACH(obj, &obj_list, next) { 2391 if (obj->marker || obj->doomed) 2392 continue; 2393 if (object_match_name(obj, name)) 2394 return (obj); 2395 } 2396 2397 path = find_library(name, refobj, &fd); 2398 if (path == NULL) 2399 return (NULL); 2400 } else 2401 path = NULL; 2402 2403 if (fd >= 0) { 2404 /* 2405 * search_library_pathfds() opens a fresh file descriptor for the 2406 * library, so there is no need to dup(). 2407 */ 2408 } else if (fd_u == -1) { 2409 /* 2410 * If we didn't find a match by pathname, or the name is not 2411 * supplied, open the file and check again by device and inode. 2412 * This avoids false mismatches caused by multiple links or ".." 2413 * in pathnames. 2414 * 2415 * To avoid a race, we open the file and use fstat() rather than 2416 * using stat(). 2417 */ 2418 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2419 _rtld_error("Cannot open \"%s\"", path); 2420 free(path); 2421 return (NULL); 2422 } 2423 } else { 2424 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2425 if (fd == -1) { 2426 _rtld_error("Cannot dup fd"); 2427 free(path); 2428 return (NULL); 2429 } 2430 } 2431 if (fstat(fd, &sb) == -1) { 2432 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2433 close(fd); 2434 free(path); 2435 return NULL; 2436 } 2437 TAILQ_FOREACH(obj, &obj_list, next) { 2438 if (obj->marker || obj->doomed) 2439 continue; 2440 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2441 break; 2442 } 2443 if (obj != NULL && name != NULL) { 2444 object_add_name(obj, name); 2445 free(path); 2446 close(fd); 2447 return obj; 2448 } 2449 if (flags & RTLD_LO_NOLOAD) { 2450 free(path); 2451 close(fd); 2452 return (NULL); 2453 } 2454 2455 /* First use of this object, so we must map it in */ 2456 obj = do_load_object(fd, name, path, &sb, flags); 2457 if (obj == NULL) 2458 free(path); 2459 close(fd); 2460 2461 return obj; 2462 } 2463 2464 static Obj_Entry * 2465 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2466 int flags) 2467 { 2468 Obj_Entry *obj; 2469 struct statfs fs; 2470 2471 /* 2472 * but first, make sure that environment variables haven't been 2473 * used to circumvent the noexec flag on a filesystem. 2474 */ 2475 if (dangerous_ld_env) { 2476 if (fstatfs(fd, &fs) != 0) { 2477 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2478 return NULL; 2479 } 2480 if (fs.f_flags & MNT_NOEXEC) { 2481 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2482 return NULL; 2483 } 2484 } 2485 dbg("loading \"%s\"", printable_path(path)); 2486 obj = map_object(fd, printable_path(path), sbp); 2487 if (obj == NULL) 2488 return NULL; 2489 2490 /* 2491 * If DT_SONAME is present in the object, digest_dynamic2 already 2492 * added it to the object names. 2493 */ 2494 if (name != NULL) 2495 object_add_name(obj, name); 2496 obj->path = path; 2497 digest_dynamic(obj, 0); 2498 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2499 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2500 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2501 RTLD_LO_DLOPEN) { 2502 dbg("refusing to load non-loadable \"%s\"", obj->path); 2503 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2504 munmap(obj->mapbase, obj->mapsize); 2505 obj_free(obj); 2506 return (NULL); 2507 } 2508 2509 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2510 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2511 obj_count++; 2512 obj_loads++; 2513 linkmap_add(obj); /* for GDB & dlinfo() */ 2514 max_stack_flags |= obj->stack_flags; 2515 2516 dbg(" %p .. %p: %s", obj->mapbase, 2517 obj->mapbase + obj->mapsize - 1, obj->path); 2518 if (obj->textrel) 2519 dbg(" WARNING: %s has impure text", obj->path); 2520 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2521 obj->path); 2522 2523 return obj; 2524 } 2525 2526 static Obj_Entry * 2527 obj_from_addr(const void *addr) 2528 { 2529 Obj_Entry *obj; 2530 2531 TAILQ_FOREACH(obj, &obj_list, next) { 2532 if (obj->marker) 2533 continue; 2534 if (addr < (void *) obj->mapbase) 2535 continue; 2536 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2537 return obj; 2538 } 2539 return NULL; 2540 } 2541 2542 static void 2543 preinit_main(void) 2544 { 2545 Elf_Addr *preinit_addr; 2546 int index; 2547 2548 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2549 if (preinit_addr == NULL) 2550 return; 2551 2552 for (index = 0; index < obj_main->preinit_array_num; index++) { 2553 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2554 dbg("calling preinit function for %s at %p", obj_main->path, 2555 (void *)preinit_addr[index]); 2556 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2557 0, 0, obj_main->path); 2558 call_init_pointer(obj_main, preinit_addr[index]); 2559 } 2560 } 2561 } 2562 2563 /* 2564 * Call the finalization functions for each of the objects in "list" 2565 * belonging to the DAG of "root" and referenced once. If NULL "root" 2566 * is specified, every finalization function will be called regardless 2567 * of the reference count and the list elements won't be freed. All of 2568 * the objects are expected to have non-NULL fini functions. 2569 */ 2570 static void 2571 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2572 { 2573 Objlist_Entry *elm; 2574 char *saved_msg; 2575 Elf_Addr *fini_addr; 2576 int index; 2577 2578 assert(root == NULL || root->refcount == 1); 2579 2580 if (root != NULL) 2581 root->doomed = true; 2582 2583 /* 2584 * Preserve the current error message since a fini function might 2585 * call into the dynamic linker and overwrite it. 2586 */ 2587 saved_msg = errmsg_save(); 2588 do { 2589 STAILQ_FOREACH(elm, list, link) { 2590 if (root != NULL && (elm->obj->refcount != 1 || 2591 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2592 continue; 2593 /* Remove object from fini list to prevent recursive invocation. */ 2594 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2595 /* Ensure that new references cannot be acquired. */ 2596 elm->obj->doomed = true; 2597 2598 hold_object(elm->obj); 2599 lock_release(rtld_bind_lock, lockstate); 2600 /* 2601 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2602 * When this happens, DT_FINI_ARRAY is processed first. 2603 */ 2604 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2605 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2606 for (index = elm->obj->fini_array_num - 1; index >= 0; 2607 index--) { 2608 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2609 dbg("calling fini function for %s at %p", 2610 elm->obj->path, (void *)fini_addr[index]); 2611 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2612 (void *)fini_addr[index], 0, 0, elm->obj->path); 2613 call_initfini_pointer(elm->obj, fini_addr[index]); 2614 } 2615 } 2616 } 2617 if (elm->obj->fini != (Elf_Addr)NULL) { 2618 dbg("calling fini function for %s at %p", elm->obj->path, 2619 (void *)elm->obj->fini); 2620 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2621 0, 0, elm->obj->path); 2622 call_initfini_pointer(elm->obj, elm->obj->fini); 2623 } 2624 wlock_acquire(rtld_bind_lock, lockstate); 2625 unhold_object(elm->obj); 2626 /* No need to free anything if process is going down. */ 2627 if (root != NULL) 2628 free(elm); 2629 /* 2630 * We must restart the list traversal after every fini call 2631 * because a dlclose() call from the fini function or from 2632 * another thread might have modified the reference counts. 2633 */ 2634 break; 2635 } 2636 } while (elm != NULL); 2637 errmsg_restore(saved_msg); 2638 } 2639 2640 /* 2641 * Call the initialization functions for each of the objects in 2642 * "list". All of the objects are expected to have non-NULL init 2643 * functions. 2644 */ 2645 static void 2646 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2647 { 2648 Objlist_Entry *elm; 2649 Obj_Entry *obj; 2650 char *saved_msg; 2651 Elf_Addr *init_addr; 2652 int index; 2653 2654 /* 2655 * Clean init_scanned flag so that objects can be rechecked and 2656 * possibly initialized earlier if any of vectors called below 2657 * cause the change by using dlopen. 2658 */ 2659 TAILQ_FOREACH(obj, &obj_list, next) { 2660 if (obj->marker) 2661 continue; 2662 obj->init_scanned = false; 2663 } 2664 2665 /* 2666 * Preserve the current error message since an init function might 2667 * call into the dynamic linker and overwrite it. 2668 */ 2669 saved_msg = errmsg_save(); 2670 STAILQ_FOREACH(elm, list, link) { 2671 if (elm->obj->init_done) /* Initialized early. */ 2672 continue; 2673 /* 2674 * Race: other thread might try to use this object before current 2675 * one completes the initialization. Not much can be done here 2676 * without better locking. 2677 */ 2678 elm->obj->init_done = true; 2679 hold_object(elm->obj); 2680 lock_release(rtld_bind_lock, lockstate); 2681 2682 /* 2683 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2684 * When this happens, DT_INIT is processed first. 2685 */ 2686 if (elm->obj->init != (Elf_Addr)NULL) { 2687 dbg("calling init function for %s at %p", elm->obj->path, 2688 (void *)elm->obj->init); 2689 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2690 0, 0, elm->obj->path); 2691 call_initfini_pointer(elm->obj, elm->obj->init); 2692 } 2693 init_addr = (Elf_Addr *)elm->obj->init_array; 2694 if (init_addr != NULL) { 2695 for (index = 0; index < elm->obj->init_array_num; index++) { 2696 if (init_addr[index] != 0 && init_addr[index] != 1) { 2697 dbg("calling init function for %s at %p", elm->obj->path, 2698 (void *)init_addr[index]); 2699 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2700 (void *)init_addr[index], 0, 0, elm->obj->path); 2701 call_init_pointer(elm->obj, init_addr[index]); 2702 } 2703 } 2704 } 2705 wlock_acquire(rtld_bind_lock, lockstate); 2706 unhold_object(elm->obj); 2707 } 2708 errmsg_restore(saved_msg); 2709 } 2710 2711 static void 2712 objlist_clear(Objlist *list) 2713 { 2714 Objlist_Entry *elm; 2715 2716 while (!STAILQ_EMPTY(list)) { 2717 elm = STAILQ_FIRST(list); 2718 STAILQ_REMOVE_HEAD(list, link); 2719 free(elm); 2720 } 2721 } 2722 2723 static Objlist_Entry * 2724 objlist_find(Objlist *list, const Obj_Entry *obj) 2725 { 2726 Objlist_Entry *elm; 2727 2728 STAILQ_FOREACH(elm, list, link) 2729 if (elm->obj == obj) 2730 return elm; 2731 return NULL; 2732 } 2733 2734 static void 2735 objlist_init(Objlist *list) 2736 { 2737 STAILQ_INIT(list); 2738 } 2739 2740 static void 2741 objlist_push_head(Objlist *list, Obj_Entry *obj) 2742 { 2743 Objlist_Entry *elm; 2744 2745 elm = NEW(Objlist_Entry); 2746 elm->obj = obj; 2747 STAILQ_INSERT_HEAD(list, elm, link); 2748 } 2749 2750 static void 2751 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2752 { 2753 Objlist_Entry *elm; 2754 2755 elm = NEW(Objlist_Entry); 2756 elm->obj = obj; 2757 STAILQ_INSERT_TAIL(list, elm, link); 2758 } 2759 2760 static void 2761 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2762 { 2763 Objlist_Entry *elm, *listelm; 2764 2765 STAILQ_FOREACH(listelm, list, link) { 2766 if (listelm->obj == listobj) 2767 break; 2768 } 2769 elm = NEW(Objlist_Entry); 2770 elm->obj = obj; 2771 if (listelm != NULL) 2772 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2773 else 2774 STAILQ_INSERT_TAIL(list, elm, link); 2775 } 2776 2777 static void 2778 objlist_remove(Objlist *list, Obj_Entry *obj) 2779 { 2780 Objlist_Entry *elm; 2781 2782 if ((elm = objlist_find(list, obj)) != NULL) { 2783 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2784 free(elm); 2785 } 2786 } 2787 2788 /* 2789 * Relocate dag rooted in the specified object. 2790 * Returns 0 on success, or -1 on failure. 2791 */ 2792 2793 static int 2794 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2795 int flags, RtldLockState *lockstate) 2796 { 2797 Objlist_Entry *elm; 2798 int error; 2799 2800 error = 0; 2801 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2802 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2803 lockstate); 2804 if (error == -1) 2805 break; 2806 } 2807 return (error); 2808 } 2809 2810 /* 2811 * Prepare for, or clean after, relocating an object marked with 2812 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2813 * segments are remapped read-write. After relocations are done, the 2814 * segment's permissions are returned back to the modes specified in 2815 * the phdrs. If any relocation happened, or always for wired 2816 * program, COW is triggered. 2817 */ 2818 static int 2819 reloc_textrel_prot(Obj_Entry *obj, bool before) 2820 { 2821 const Elf_Phdr *ph; 2822 void *base; 2823 size_t l, sz; 2824 int prot; 2825 2826 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2827 l--, ph++) { 2828 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2829 continue; 2830 base = obj->relocbase + trunc_page(ph->p_vaddr); 2831 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2832 trunc_page(ph->p_vaddr); 2833 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2834 if (mprotect(base, sz, prot) == -1) { 2835 _rtld_error("%s: Cannot write-%sable text segment: %s", 2836 obj->path, before ? "en" : "dis", 2837 rtld_strerror(errno)); 2838 return (-1); 2839 } 2840 } 2841 return (0); 2842 } 2843 2844 /* 2845 * Relocate single object. 2846 * Returns 0 on success, or -1 on failure. 2847 */ 2848 static int 2849 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2850 int flags, RtldLockState *lockstate) 2851 { 2852 2853 if (obj->relocated) 2854 return (0); 2855 obj->relocated = true; 2856 if (obj != rtldobj) 2857 dbg("relocating \"%s\"", obj->path); 2858 2859 if (obj->symtab == NULL || obj->strtab == NULL || 2860 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2861 _rtld_error("%s: Shared object has no run-time symbol table", 2862 obj->path); 2863 return (-1); 2864 } 2865 2866 /* There are relocations to the write-protected text segment. */ 2867 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2868 return (-1); 2869 2870 /* Process the non-PLT non-IFUNC relocations. */ 2871 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2872 return (-1); 2873 2874 /* Re-protected the text segment. */ 2875 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2876 return (-1); 2877 2878 /* Set the special PLT or GOT entries. */ 2879 init_pltgot(obj); 2880 2881 /* Process the PLT relocations. */ 2882 if (reloc_plt(obj) == -1) 2883 return (-1); 2884 /* Relocate the jump slots if we are doing immediate binding. */ 2885 if (obj->bind_now || bind_now) 2886 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2887 return (-1); 2888 2889 /* 2890 * Process the non-PLT IFUNC relocations. The relocations are 2891 * processed in two phases, because IFUNC resolvers may 2892 * reference other symbols, which must be readily processed 2893 * before resolvers are called. 2894 */ 2895 if (obj->non_plt_gnu_ifunc && 2896 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2897 return (-1); 2898 2899 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2900 return (-1); 2901 2902 /* 2903 * Set up the magic number and version in the Obj_Entry. These 2904 * were checked in the crt1.o from the original ElfKit, so we 2905 * set them for backward compatibility. 2906 */ 2907 obj->magic = RTLD_MAGIC; 2908 obj->version = RTLD_VERSION; 2909 2910 return (0); 2911 } 2912 2913 /* 2914 * Relocate newly-loaded shared objects. The argument is a pointer to 2915 * the Obj_Entry for the first such object. All objects from the first 2916 * to the end of the list of objects are relocated. Returns 0 on success, 2917 * or -1 on failure. 2918 */ 2919 static int 2920 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2921 int flags, RtldLockState *lockstate) 2922 { 2923 Obj_Entry *obj; 2924 int error; 2925 2926 for (error = 0, obj = first; obj != NULL; 2927 obj = TAILQ_NEXT(obj, next)) { 2928 if (obj->marker) 2929 continue; 2930 error = relocate_object(obj, bind_now, rtldobj, flags, 2931 lockstate); 2932 if (error == -1) 2933 break; 2934 } 2935 return (error); 2936 } 2937 2938 /* 2939 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2940 * referencing STT_GNU_IFUNC symbols is postponed till the other 2941 * relocations are done. The indirect functions specified as 2942 * ifunc are allowed to call other symbols, so we need to have 2943 * objects relocated before asking for resolution from indirects. 2944 * 2945 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2946 * instead of the usual lazy handling of PLT slots. It is 2947 * consistent with how GNU does it. 2948 */ 2949 static int 2950 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2951 RtldLockState *lockstate) 2952 { 2953 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2954 return (-1); 2955 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2956 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2957 return (-1); 2958 return (0); 2959 } 2960 2961 static int 2962 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2963 RtldLockState *lockstate) 2964 { 2965 Obj_Entry *obj; 2966 2967 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2968 if (obj->marker) 2969 continue; 2970 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2971 return (-1); 2972 } 2973 return (0); 2974 } 2975 2976 static int 2977 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2978 RtldLockState *lockstate) 2979 { 2980 Objlist_Entry *elm; 2981 2982 STAILQ_FOREACH(elm, list, link) { 2983 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2984 lockstate) == -1) 2985 return (-1); 2986 } 2987 return (0); 2988 } 2989 2990 /* 2991 * Cleanup procedure. It will be called (by the atexit mechanism) just 2992 * before the process exits. 2993 */ 2994 static void 2995 rtld_exit(void) 2996 { 2997 RtldLockState lockstate; 2998 2999 wlock_acquire(rtld_bind_lock, &lockstate); 3000 dbg("rtld_exit()"); 3001 objlist_call_fini(&list_fini, NULL, &lockstate); 3002 /* No need to remove the items from the list, since we are exiting. */ 3003 if (!libmap_disable) 3004 lm_fini(); 3005 lock_release(rtld_bind_lock, &lockstate); 3006 } 3007 3008 /* 3009 * Iterate over a search path, translate each element, and invoke the 3010 * callback on the result. 3011 */ 3012 static void * 3013 path_enumerate(const char *path, path_enum_proc callback, 3014 const char *refobj_path, void *arg) 3015 { 3016 const char *trans; 3017 if (path == NULL) 3018 return (NULL); 3019 3020 path += strspn(path, ":;"); 3021 while (*path != '\0') { 3022 size_t len; 3023 char *res; 3024 3025 len = strcspn(path, ":;"); 3026 trans = lm_findn(refobj_path, path, len); 3027 if (trans) 3028 res = callback(trans, strlen(trans), arg); 3029 else 3030 res = callback(path, len, arg); 3031 3032 if (res != NULL) 3033 return (res); 3034 3035 path += len; 3036 path += strspn(path, ":;"); 3037 } 3038 3039 return (NULL); 3040 } 3041 3042 struct try_library_args { 3043 const char *name; 3044 size_t namelen; 3045 char *buffer; 3046 size_t buflen; 3047 int fd; 3048 }; 3049 3050 static void * 3051 try_library_path(const char *dir, size_t dirlen, void *param) 3052 { 3053 struct try_library_args *arg; 3054 int fd; 3055 3056 arg = param; 3057 if (*dir == '/' || trust) { 3058 char *pathname; 3059 3060 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3061 return (NULL); 3062 3063 pathname = arg->buffer; 3064 strncpy(pathname, dir, dirlen); 3065 pathname[dirlen] = '/'; 3066 strcpy(pathname + dirlen + 1, arg->name); 3067 3068 dbg(" Trying \"%s\"", pathname); 3069 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3070 if (fd >= 0) { 3071 dbg(" Opened \"%s\", fd %d", pathname, fd); 3072 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3073 strcpy(pathname, arg->buffer); 3074 arg->fd = fd; 3075 return (pathname); 3076 } else { 3077 dbg(" Failed to open \"%s\": %s", 3078 pathname, rtld_strerror(errno)); 3079 } 3080 } 3081 return (NULL); 3082 } 3083 3084 static char * 3085 search_library_path(const char *name, const char *path, 3086 const char *refobj_path, int *fdp) 3087 { 3088 char *p; 3089 struct try_library_args arg; 3090 3091 if (path == NULL) 3092 return NULL; 3093 3094 arg.name = name; 3095 arg.namelen = strlen(name); 3096 arg.buffer = xmalloc(PATH_MAX); 3097 arg.buflen = PATH_MAX; 3098 arg.fd = -1; 3099 3100 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3101 *fdp = arg.fd; 3102 3103 free(arg.buffer); 3104 3105 return (p); 3106 } 3107 3108 3109 /* 3110 * Finds the library with the given name using the directory descriptors 3111 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3112 * 3113 * Returns a freshly-opened close-on-exec file descriptor for the library, 3114 * or -1 if the library cannot be found. 3115 */ 3116 static char * 3117 search_library_pathfds(const char *name, const char *path, int *fdp) 3118 { 3119 char *envcopy, *fdstr, *found, *last_token; 3120 size_t len; 3121 int dirfd, fd; 3122 3123 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3124 3125 /* Don't load from user-specified libdirs into setuid binaries. */ 3126 if (!trust) 3127 return (NULL); 3128 3129 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3130 if (path == NULL) 3131 return (NULL); 3132 3133 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3134 if (name[0] == '/') { 3135 dbg("Absolute path (%s) passed to %s", name, __func__); 3136 return (NULL); 3137 } 3138 3139 /* 3140 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3141 * copy of the path, as strtok_r rewrites separator tokens 3142 * with '\0'. 3143 */ 3144 found = NULL; 3145 envcopy = xstrdup(path); 3146 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3147 fdstr = strtok_r(NULL, ":", &last_token)) { 3148 dirfd = parse_integer(fdstr); 3149 if (dirfd < 0) { 3150 _rtld_error("failed to parse directory FD: '%s'", 3151 fdstr); 3152 break; 3153 } 3154 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3155 if (fd >= 0) { 3156 *fdp = fd; 3157 len = strlen(fdstr) + strlen(name) + 3; 3158 found = xmalloc(len); 3159 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3160 _rtld_error("error generating '%d/%s'", 3161 dirfd, name); 3162 rtld_die(); 3163 } 3164 dbg("open('%s') => %d", found, fd); 3165 break; 3166 } 3167 } 3168 free(envcopy); 3169 3170 return (found); 3171 } 3172 3173 3174 int 3175 dlclose(void *handle) 3176 { 3177 RtldLockState lockstate; 3178 int error; 3179 3180 wlock_acquire(rtld_bind_lock, &lockstate); 3181 error = dlclose_locked(handle, &lockstate); 3182 lock_release(rtld_bind_lock, &lockstate); 3183 return (error); 3184 } 3185 3186 static int 3187 dlclose_locked(void *handle, RtldLockState *lockstate) 3188 { 3189 Obj_Entry *root; 3190 3191 root = dlcheck(handle); 3192 if (root == NULL) 3193 return -1; 3194 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3195 root->path); 3196 3197 /* Unreference the object and its dependencies. */ 3198 root->dl_refcount--; 3199 3200 if (root->refcount == 1) { 3201 /* 3202 * The object will be no longer referenced, so we must unload it. 3203 * First, call the fini functions. 3204 */ 3205 objlist_call_fini(&list_fini, root, lockstate); 3206 3207 unref_dag(root); 3208 3209 /* Finish cleaning up the newly-unreferenced objects. */ 3210 GDB_STATE(RT_DELETE,&root->linkmap); 3211 unload_object(root, lockstate); 3212 GDB_STATE(RT_CONSISTENT,NULL); 3213 } else 3214 unref_dag(root); 3215 3216 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3217 return 0; 3218 } 3219 3220 char * 3221 dlerror(void) 3222 { 3223 char *msg = error_message; 3224 error_message = NULL; 3225 return msg; 3226 } 3227 3228 /* 3229 * This function is deprecated and has no effect. 3230 */ 3231 void 3232 dllockinit(void *context, 3233 void *(*_lock_create)(void *context) __unused, 3234 void (*_rlock_acquire)(void *lock) __unused, 3235 void (*_wlock_acquire)(void *lock) __unused, 3236 void (*_lock_release)(void *lock) __unused, 3237 void (*_lock_destroy)(void *lock) __unused, 3238 void (*context_destroy)(void *context)) 3239 { 3240 static void *cur_context; 3241 static void (*cur_context_destroy)(void *); 3242 3243 /* Just destroy the context from the previous call, if necessary. */ 3244 if (cur_context_destroy != NULL) 3245 cur_context_destroy(cur_context); 3246 cur_context = context; 3247 cur_context_destroy = context_destroy; 3248 } 3249 3250 void * 3251 dlopen(const char *name, int mode) 3252 { 3253 3254 return (rtld_dlopen(name, -1, mode)); 3255 } 3256 3257 void * 3258 fdlopen(int fd, int mode) 3259 { 3260 3261 return (rtld_dlopen(NULL, fd, mode)); 3262 } 3263 3264 static void * 3265 rtld_dlopen(const char *name, int fd, int mode) 3266 { 3267 RtldLockState lockstate; 3268 int lo_flags; 3269 3270 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3271 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3272 if (ld_tracing != NULL) { 3273 rlock_acquire(rtld_bind_lock, &lockstate); 3274 if (sigsetjmp(lockstate.env, 0) != 0) 3275 lock_upgrade(rtld_bind_lock, &lockstate); 3276 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3277 lock_release(rtld_bind_lock, &lockstate); 3278 } 3279 lo_flags = RTLD_LO_DLOPEN; 3280 if (mode & RTLD_NODELETE) 3281 lo_flags |= RTLD_LO_NODELETE; 3282 if (mode & RTLD_NOLOAD) 3283 lo_flags |= RTLD_LO_NOLOAD; 3284 if (ld_tracing != NULL) 3285 lo_flags |= RTLD_LO_TRACE; 3286 3287 return (dlopen_object(name, fd, obj_main, lo_flags, 3288 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3289 } 3290 3291 static void 3292 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3293 { 3294 3295 obj->dl_refcount--; 3296 unref_dag(obj); 3297 if (obj->refcount == 0) 3298 unload_object(obj, lockstate); 3299 } 3300 3301 static Obj_Entry * 3302 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3303 int mode, RtldLockState *lockstate) 3304 { 3305 Obj_Entry *old_obj_tail; 3306 Obj_Entry *obj; 3307 Objlist initlist; 3308 RtldLockState mlockstate; 3309 int result; 3310 3311 objlist_init(&initlist); 3312 3313 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3314 wlock_acquire(rtld_bind_lock, &mlockstate); 3315 lockstate = &mlockstate; 3316 } 3317 GDB_STATE(RT_ADD,NULL); 3318 3319 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3320 obj = NULL; 3321 if (name == NULL && fd == -1) { 3322 obj = obj_main; 3323 obj->refcount++; 3324 } else { 3325 obj = load_object(name, fd, refobj, lo_flags); 3326 } 3327 3328 if (obj) { 3329 obj->dl_refcount++; 3330 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3331 objlist_push_tail(&list_global, obj); 3332 if (globallist_next(old_obj_tail) != NULL) { 3333 /* We loaded something new. */ 3334 assert(globallist_next(old_obj_tail) == obj); 3335 result = load_needed_objects(obj, 3336 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3337 init_dag(obj); 3338 ref_dag(obj); 3339 if (result != -1) 3340 result = rtld_verify_versions(&obj->dagmembers); 3341 if (result != -1 && ld_tracing) 3342 goto trace; 3343 if (result == -1 || relocate_object_dag(obj, 3344 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3345 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3346 lockstate) == -1) { 3347 dlopen_cleanup(obj, lockstate); 3348 obj = NULL; 3349 } else if (lo_flags & RTLD_LO_EARLY) { 3350 /* 3351 * Do not call the init functions for early loaded 3352 * filtees. The image is still not initialized enough 3353 * for them to work. 3354 * 3355 * Our object is found by the global object list and 3356 * will be ordered among all init calls done right 3357 * before transferring control to main. 3358 */ 3359 } else { 3360 /* Make list of init functions to call. */ 3361 initlist_add_objects(obj, obj, &initlist); 3362 } 3363 /* 3364 * Process all no_delete or global objects here, given 3365 * them own DAGs to prevent their dependencies from being 3366 * unloaded. This has to be done after we have loaded all 3367 * of the dependencies, so that we do not miss any. 3368 */ 3369 if (obj != NULL) 3370 process_z(obj); 3371 } else { 3372 /* 3373 * Bump the reference counts for objects on this DAG. If 3374 * this is the first dlopen() call for the object that was 3375 * already loaded as a dependency, initialize the dag 3376 * starting at it. 3377 */ 3378 init_dag(obj); 3379 ref_dag(obj); 3380 3381 if ((lo_flags & RTLD_LO_TRACE) != 0) 3382 goto trace; 3383 } 3384 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3385 obj->z_nodelete) && !obj->ref_nodel) { 3386 dbg("obj %s nodelete", obj->path); 3387 ref_dag(obj); 3388 obj->z_nodelete = obj->ref_nodel = true; 3389 } 3390 } 3391 3392 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3393 name); 3394 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3395 3396 if (!(lo_flags & RTLD_LO_EARLY)) { 3397 map_stacks_exec(lockstate); 3398 } 3399 3400 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3401 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3402 lockstate) == -1) { 3403 objlist_clear(&initlist); 3404 dlopen_cleanup(obj, lockstate); 3405 if (lockstate == &mlockstate) 3406 lock_release(rtld_bind_lock, lockstate); 3407 return (NULL); 3408 } 3409 3410 if (!(lo_flags & RTLD_LO_EARLY)) { 3411 /* Call the init functions. */ 3412 objlist_call_init(&initlist, lockstate); 3413 } 3414 objlist_clear(&initlist); 3415 if (lockstate == &mlockstate) 3416 lock_release(rtld_bind_lock, lockstate); 3417 return obj; 3418 trace: 3419 trace_loaded_objects(obj); 3420 if (lockstate == &mlockstate) 3421 lock_release(rtld_bind_lock, lockstate); 3422 exit(0); 3423 } 3424 3425 static void * 3426 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3427 int flags) 3428 { 3429 DoneList donelist; 3430 const Obj_Entry *obj, *defobj; 3431 const Elf_Sym *def; 3432 SymLook req; 3433 RtldLockState lockstate; 3434 tls_index ti; 3435 void *sym; 3436 int res; 3437 3438 def = NULL; 3439 defobj = NULL; 3440 symlook_init(&req, name); 3441 req.ventry = ve; 3442 req.flags = flags | SYMLOOK_IN_PLT; 3443 req.lockstate = &lockstate; 3444 3445 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3446 rlock_acquire(rtld_bind_lock, &lockstate); 3447 if (sigsetjmp(lockstate.env, 0) != 0) 3448 lock_upgrade(rtld_bind_lock, &lockstate); 3449 if (handle == NULL || handle == RTLD_NEXT || 3450 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3451 3452 if ((obj = obj_from_addr(retaddr)) == NULL) { 3453 _rtld_error("Cannot determine caller's shared object"); 3454 lock_release(rtld_bind_lock, &lockstate); 3455 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3456 return NULL; 3457 } 3458 if (handle == NULL) { /* Just the caller's shared object. */ 3459 res = symlook_obj(&req, obj); 3460 if (res == 0) { 3461 def = req.sym_out; 3462 defobj = req.defobj_out; 3463 } 3464 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3465 handle == RTLD_SELF) { /* ... caller included */ 3466 if (handle == RTLD_NEXT) 3467 obj = globallist_next(obj); 3468 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3469 if (obj->marker) 3470 continue; 3471 res = symlook_obj(&req, obj); 3472 if (res == 0) { 3473 if (def == NULL || 3474 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3475 def = req.sym_out; 3476 defobj = req.defobj_out; 3477 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3478 break; 3479 } 3480 } 3481 } 3482 /* 3483 * Search the dynamic linker itself, and possibly resolve the 3484 * symbol from there. This is how the application links to 3485 * dynamic linker services such as dlopen. 3486 */ 3487 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3488 res = symlook_obj(&req, &obj_rtld); 3489 if (res == 0) { 3490 def = req.sym_out; 3491 defobj = req.defobj_out; 3492 } 3493 } 3494 } else { 3495 assert(handle == RTLD_DEFAULT); 3496 res = symlook_default(&req, obj); 3497 if (res == 0) { 3498 defobj = req.defobj_out; 3499 def = req.sym_out; 3500 } 3501 } 3502 } else { 3503 if ((obj = dlcheck(handle)) == NULL) { 3504 lock_release(rtld_bind_lock, &lockstate); 3505 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3506 return NULL; 3507 } 3508 3509 donelist_init(&donelist); 3510 if (obj->mainprog) { 3511 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3512 res = symlook_global(&req, &donelist); 3513 if (res == 0) { 3514 def = req.sym_out; 3515 defobj = req.defobj_out; 3516 } 3517 /* 3518 * Search the dynamic linker itself, and possibly resolve the 3519 * symbol from there. This is how the application links to 3520 * dynamic linker services such as dlopen. 3521 */ 3522 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3523 res = symlook_obj(&req, &obj_rtld); 3524 if (res == 0) { 3525 def = req.sym_out; 3526 defobj = req.defobj_out; 3527 } 3528 } 3529 } 3530 else { 3531 /* Search the whole DAG rooted at the given object. */ 3532 res = symlook_list(&req, &obj->dagmembers, &donelist); 3533 if (res == 0) { 3534 def = req.sym_out; 3535 defobj = req.defobj_out; 3536 } 3537 } 3538 } 3539 3540 if (def != NULL) { 3541 lock_release(rtld_bind_lock, &lockstate); 3542 3543 /* 3544 * The value required by the caller is derived from the value 3545 * of the symbol. this is simply the relocated value of the 3546 * symbol. 3547 */ 3548 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3549 sym = make_function_pointer(def, defobj); 3550 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3551 sym = rtld_resolve_ifunc(defobj, def); 3552 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3553 ti.ti_module = defobj->tlsindex; 3554 ti.ti_offset = def->st_value; 3555 sym = __tls_get_addr(&ti); 3556 } else 3557 sym = defobj->relocbase + def->st_value; 3558 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3559 return (sym); 3560 } 3561 3562 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3563 ve != NULL ? ve->name : ""); 3564 lock_release(rtld_bind_lock, &lockstate); 3565 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3566 return NULL; 3567 } 3568 3569 void * 3570 dlsym(void *handle, const char *name) 3571 { 3572 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3573 SYMLOOK_DLSYM); 3574 } 3575 3576 dlfunc_t 3577 dlfunc(void *handle, const char *name) 3578 { 3579 union { 3580 void *d; 3581 dlfunc_t f; 3582 } rv; 3583 3584 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3585 SYMLOOK_DLSYM); 3586 return (rv.f); 3587 } 3588 3589 void * 3590 dlvsym(void *handle, const char *name, const char *version) 3591 { 3592 Ver_Entry ventry; 3593 3594 ventry.name = version; 3595 ventry.file = NULL; 3596 ventry.hash = elf_hash(version); 3597 ventry.flags= 0; 3598 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3599 SYMLOOK_DLSYM); 3600 } 3601 3602 int 3603 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3604 { 3605 const Obj_Entry *obj; 3606 RtldLockState lockstate; 3607 3608 rlock_acquire(rtld_bind_lock, &lockstate); 3609 obj = obj_from_addr(addr); 3610 if (obj == NULL) { 3611 _rtld_error("No shared object contains address"); 3612 lock_release(rtld_bind_lock, &lockstate); 3613 return (0); 3614 } 3615 rtld_fill_dl_phdr_info(obj, phdr_info); 3616 lock_release(rtld_bind_lock, &lockstate); 3617 return (1); 3618 } 3619 3620 int 3621 dladdr(const void *addr, Dl_info *info) 3622 { 3623 const Obj_Entry *obj; 3624 const Elf_Sym *def; 3625 void *symbol_addr; 3626 unsigned long symoffset; 3627 RtldLockState lockstate; 3628 3629 rlock_acquire(rtld_bind_lock, &lockstate); 3630 obj = obj_from_addr(addr); 3631 if (obj == NULL) { 3632 _rtld_error("No shared object contains address"); 3633 lock_release(rtld_bind_lock, &lockstate); 3634 return 0; 3635 } 3636 info->dli_fname = obj->path; 3637 info->dli_fbase = obj->mapbase; 3638 info->dli_saddr = (void *)0; 3639 info->dli_sname = NULL; 3640 3641 /* 3642 * Walk the symbol list looking for the symbol whose address is 3643 * closest to the address sent in. 3644 */ 3645 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3646 def = obj->symtab + symoffset; 3647 3648 /* 3649 * For skip the symbol if st_shndx is either SHN_UNDEF or 3650 * SHN_COMMON. 3651 */ 3652 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3653 continue; 3654 3655 /* 3656 * If the symbol is greater than the specified address, or if it 3657 * is further away from addr than the current nearest symbol, 3658 * then reject it. 3659 */ 3660 symbol_addr = obj->relocbase + def->st_value; 3661 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3662 continue; 3663 3664 /* Update our idea of the nearest symbol. */ 3665 info->dli_sname = obj->strtab + def->st_name; 3666 info->dli_saddr = symbol_addr; 3667 3668 /* Exact match? */ 3669 if (info->dli_saddr == addr) 3670 break; 3671 } 3672 lock_release(rtld_bind_lock, &lockstate); 3673 return 1; 3674 } 3675 3676 int 3677 dlinfo(void *handle, int request, void *p) 3678 { 3679 const Obj_Entry *obj; 3680 RtldLockState lockstate; 3681 int error; 3682 3683 rlock_acquire(rtld_bind_lock, &lockstate); 3684 3685 if (handle == NULL || handle == RTLD_SELF) { 3686 void *retaddr; 3687 3688 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3689 if ((obj = obj_from_addr(retaddr)) == NULL) 3690 _rtld_error("Cannot determine caller's shared object"); 3691 } else 3692 obj = dlcheck(handle); 3693 3694 if (obj == NULL) { 3695 lock_release(rtld_bind_lock, &lockstate); 3696 return (-1); 3697 } 3698 3699 error = 0; 3700 switch (request) { 3701 case RTLD_DI_LINKMAP: 3702 *((struct link_map const **)p) = &obj->linkmap; 3703 break; 3704 case RTLD_DI_ORIGIN: 3705 error = rtld_dirname(obj->path, p); 3706 break; 3707 3708 case RTLD_DI_SERINFOSIZE: 3709 case RTLD_DI_SERINFO: 3710 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3711 break; 3712 3713 default: 3714 _rtld_error("Invalid request %d passed to dlinfo()", request); 3715 error = -1; 3716 } 3717 3718 lock_release(rtld_bind_lock, &lockstate); 3719 3720 return (error); 3721 } 3722 3723 static void 3724 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3725 { 3726 3727 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3728 phdr_info->dlpi_name = obj->path; 3729 phdr_info->dlpi_phdr = obj->phdr; 3730 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3731 phdr_info->dlpi_tls_modid = obj->tlsindex; 3732 phdr_info->dlpi_tls_data = obj->tlsinit; 3733 phdr_info->dlpi_adds = obj_loads; 3734 phdr_info->dlpi_subs = obj_loads - obj_count; 3735 } 3736 3737 int 3738 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3739 { 3740 struct dl_phdr_info phdr_info; 3741 Obj_Entry *obj, marker; 3742 RtldLockState bind_lockstate, phdr_lockstate; 3743 int error; 3744 3745 init_marker(&marker); 3746 error = 0; 3747 3748 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3749 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3750 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3751 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3752 rtld_fill_dl_phdr_info(obj, &phdr_info); 3753 hold_object(obj); 3754 lock_release(rtld_bind_lock, &bind_lockstate); 3755 3756 error = callback(&phdr_info, sizeof phdr_info, param); 3757 3758 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3759 unhold_object(obj); 3760 obj = globallist_next(&marker); 3761 TAILQ_REMOVE(&obj_list, &marker, next); 3762 if (error != 0) { 3763 lock_release(rtld_bind_lock, &bind_lockstate); 3764 lock_release(rtld_phdr_lock, &phdr_lockstate); 3765 return (error); 3766 } 3767 } 3768 3769 if (error == 0) { 3770 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3771 lock_release(rtld_bind_lock, &bind_lockstate); 3772 error = callback(&phdr_info, sizeof(phdr_info), param); 3773 } 3774 lock_release(rtld_phdr_lock, &phdr_lockstate); 3775 return (error); 3776 } 3777 3778 static void * 3779 fill_search_info(const char *dir, size_t dirlen, void *param) 3780 { 3781 struct fill_search_info_args *arg; 3782 3783 arg = param; 3784 3785 if (arg->request == RTLD_DI_SERINFOSIZE) { 3786 arg->serinfo->dls_cnt ++; 3787 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3788 } else { 3789 struct dl_serpath *s_entry; 3790 3791 s_entry = arg->serpath; 3792 s_entry->dls_name = arg->strspace; 3793 s_entry->dls_flags = arg->flags; 3794 3795 strncpy(arg->strspace, dir, dirlen); 3796 arg->strspace[dirlen] = '\0'; 3797 3798 arg->strspace += dirlen + 1; 3799 arg->serpath++; 3800 } 3801 3802 return (NULL); 3803 } 3804 3805 static int 3806 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3807 { 3808 struct dl_serinfo _info; 3809 struct fill_search_info_args args; 3810 3811 args.request = RTLD_DI_SERINFOSIZE; 3812 args.serinfo = &_info; 3813 3814 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3815 _info.dls_cnt = 0; 3816 3817 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3818 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3819 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3820 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3821 if (!obj->z_nodeflib) 3822 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3823 3824 3825 if (request == RTLD_DI_SERINFOSIZE) { 3826 info->dls_size = _info.dls_size; 3827 info->dls_cnt = _info.dls_cnt; 3828 return (0); 3829 } 3830 3831 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3832 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3833 return (-1); 3834 } 3835 3836 args.request = RTLD_DI_SERINFO; 3837 args.serinfo = info; 3838 args.serpath = &info->dls_serpath[0]; 3839 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3840 3841 args.flags = LA_SER_RUNPATH; 3842 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3843 return (-1); 3844 3845 args.flags = LA_SER_LIBPATH; 3846 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3847 return (-1); 3848 3849 args.flags = LA_SER_RUNPATH; 3850 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3851 return (-1); 3852 3853 args.flags = LA_SER_CONFIG; 3854 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3855 != NULL) 3856 return (-1); 3857 3858 args.flags = LA_SER_DEFAULT; 3859 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3860 fill_search_info, NULL, &args) != NULL) 3861 return (-1); 3862 return (0); 3863 } 3864 3865 static int 3866 rtld_dirname(const char *path, char *bname) 3867 { 3868 const char *endp; 3869 3870 /* Empty or NULL string gets treated as "." */ 3871 if (path == NULL || *path == '\0') { 3872 bname[0] = '.'; 3873 bname[1] = '\0'; 3874 return (0); 3875 } 3876 3877 /* Strip trailing slashes */ 3878 endp = path + strlen(path) - 1; 3879 while (endp > path && *endp == '/') 3880 endp--; 3881 3882 /* Find the start of the dir */ 3883 while (endp > path && *endp != '/') 3884 endp--; 3885 3886 /* Either the dir is "/" or there are no slashes */ 3887 if (endp == path) { 3888 bname[0] = *endp == '/' ? '/' : '.'; 3889 bname[1] = '\0'; 3890 return (0); 3891 } else { 3892 do { 3893 endp--; 3894 } while (endp > path && *endp == '/'); 3895 } 3896 3897 if (endp - path + 2 > PATH_MAX) 3898 { 3899 _rtld_error("Filename is too long: %s", path); 3900 return(-1); 3901 } 3902 3903 strncpy(bname, path, endp - path + 1); 3904 bname[endp - path + 1] = '\0'; 3905 return (0); 3906 } 3907 3908 static int 3909 rtld_dirname_abs(const char *path, char *base) 3910 { 3911 char *last; 3912 3913 if (realpath(path, base) == NULL) 3914 return (-1); 3915 dbg("%s -> %s", path, base); 3916 last = strrchr(base, '/'); 3917 if (last == NULL) 3918 return (-1); 3919 if (last != base) 3920 *last = '\0'; 3921 return (0); 3922 } 3923 3924 static void 3925 linkmap_add(Obj_Entry *obj) 3926 { 3927 struct link_map *l = &obj->linkmap; 3928 struct link_map *prev; 3929 3930 obj->linkmap.l_name = obj->path; 3931 obj->linkmap.l_addr = obj->mapbase; 3932 obj->linkmap.l_ld = obj->dynamic; 3933 #ifdef __mips__ 3934 /* GDB needs load offset on MIPS to use the symbols */ 3935 obj->linkmap.l_offs = obj->relocbase; 3936 #endif 3937 3938 if (r_debug.r_map == NULL) { 3939 r_debug.r_map = l; 3940 return; 3941 } 3942 3943 /* 3944 * Scan to the end of the list, but not past the entry for the 3945 * dynamic linker, which we want to keep at the very end. 3946 */ 3947 for (prev = r_debug.r_map; 3948 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3949 prev = prev->l_next) 3950 ; 3951 3952 /* Link in the new entry. */ 3953 l->l_prev = prev; 3954 l->l_next = prev->l_next; 3955 if (l->l_next != NULL) 3956 l->l_next->l_prev = l; 3957 prev->l_next = l; 3958 } 3959 3960 static void 3961 linkmap_delete(Obj_Entry *obj) 3962 { 3963 struct link_map *l = &obj->linkmap; 3964 3965 if (l->l_prev == NULL) { 3966 if ((r_debug.r_map = l->l_next) != NULL) 3967 l->l_next->l_prev = NULL; 3968 return; 3969 } 3970 3971 if ((l->l_prev->l_next = l->l_next) != NULL) 3972 l->l_next->l_prev = l->l_prev; 3973 } 3974 3975 /* 3976 * Function for the debugger to set a breakpoint on to gain control. 3977 * 3978 * The two parameters allow the debugger to easily find and determine 3979 * what the runtime loader is doing and to whom it is doing it. 3980 * 3981 * When the loadhook trap is hit (r_debug_state, set at program 3982 * initialization), the arguments can be found on the stack: 3983 * 3984 * +8 struct link_map *m 3985 * +4 struct r_debug *rd 3986 * +0 RetAddr 3987 */ 3988 void 3989 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3990 { 3991 /* 3992 * The following is a hack to force the compiler to emit calls to 3993 * this function, even when optimizing. If the function is empty, 3994 * the compiler is not obliged to emit any code for calls to it, 3995 * even when marked __noinline. However, gdb depends on those 3996 * calls being made. 3997 */ 3998 __compiler_membar(); 3999 } 4000 4001 /* 4002 * A function called after init routines have completed. This can be used to 4003 * break before a program's entry routine is called, and can be used when 4004 * main is not available in the symbol table. 4005 */ 4006 void 4007 _r_debug_postinit(struct link_map *m __unused) 4008 { 4009 4010 /* See r_debug_state(). */ 4011 __compiler_membar(); 4012 } 4013 4014 static void 4015 release_object(Obj_Entry *obj) 4016 { 4017 4018 if (obj->holdcount > 0) { 4019 obj->unholdfree = true; 4020 return; 4021 } 4022 munmap(obj->mapbase, obj->mapsize); 4023 linkmap_delete(obj); 4024 obj_free(obj); 4025 } 4026 4027 /* 4028 * Get address of the pointer variable in the main program. 4029 * Prefer non-weak symbol over the weak one. 4030 */ 4031 static const void ** 4032 get_program_var_addr(const char *name, RtldLockState *lockstate) 4033 { 4034 SymLook req; 4035 DoneList donelist; 4036 4037 symlook_init(&req, name); 4038 req.lockstate = lockstate; 4039 donelist_init(&donelist); 4040 if (symlook_global(&req, &donelist) != 0) 4041 return (NULL); 4042 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4043 return ((const void **)make_function_pointer(req.sym_out, 4044 req.defobj_out)); 4045 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4046 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4047 else 4048 return ((const void **)(req.defobj_out->relocbase + 4049 req.sym_out->st_value)); 4050 } 4051 4052 /* 4053 * Set a pointer variable in the main program to the given value. This 4054 * is used to set key variables such as "environ" before any of the 4055 * init functions are called. 4056 */ 4057 static void 4058 set_program_var(const char *name, const void *value) 4059 { 4060 const void **addr; 4061 4062 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4063 dbg("\"%s\": *%p <-- %p", name, addr, value); 4064 *addr = value; 4065 } 4066 } 4067 4068 /* 4069 * Search the global objects, including dependencies and main object, 4070 * for the given symbol. 4071 */ 4072 static int 4073 symlook_global(SymLook *req, DoneList *donelist) 4074 { 4075 SymLook req1; 4076 const Objlist_Entry *elm; 4077 int res; 4078 4079 symlook_init_from_req(&req1, req); 4080 4081 /* Search all objects loaded at program start up. */ 4082 if (req->defobj_out == NULL || 4083 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4084 res = symlook_list(&req1, &list_main, donelist); 4085 if (res == 0 && (req->defobj_out == NULL || 4086 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4087 req->sym_out = req1.sym_out; 4088 req->defobj_out = req1.defobj_out; 4089 assert(req->defobj_out != NULL); 4090 } 4091 } 4092 4093 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4094 STAILQ_FOREACH(elm, &list_global, link) { 4095 if (req->defobj_out != NULL && 4096 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4097 break; 4098 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4099 if (res == 0 && (req->defobj_out == NULL || 4100 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4101 req->sym_out = req1.sym_out; 4102 req->defobj_out = req1.defobj_out; 4103 assert(req->defobj_out != NULL); 4104 } 4105 } 4106 4107 return (req->sym_out != NULL ? 0 : ESRCH); 4108 } 4109 4110 /* 4111 * Given a symbol name in a referencing object, find the corresponding 4112 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4113 * no definition was found. Returns a pointer to the Obj_Entry of the 4114 * defining object via the reference parameter DEFOBJ_OUT. 4115 */ 4116 static int 4117 symlook_default(SymLook *req, const Obj_Entry *refobj) 4118 { 4119 DoneList donelist; 4120 const Objlist_Entry *elm; 4121 SymLook req1; 4122 int res; 4123 4124 donelist_init(&donelist); 4125 symlook_init_from_req(&req1, req); 4126 4127 /* 4128 * Look first in the referencing object if linked symbolically, 4129 * and similarly handle protected symbols. 4130 */ 4131 res = symlook_obj(&req1, refobj); 4132 if (res == 0 && (refobj->symbolic || 4133 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4134 req->sym_out = req1.sym_out; 4135 req->defobj_out = req1.defobj_out; 4136 assert(req->defobj_out != NULL); 4137 } 4138 if (refobj->symbolic || req->defobj_out != NULL) 4139 donelist_check(&donelist, refobj); 4140 4141 symlook_global(req, &donelist); 4142 4143 /* Search all dlopened DAGs containing the referencing object. */ 4144 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4145 if (req->sym_out != NULL && 4146 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4147 break; 4148 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4149 if (res == 0 && (req->sym_out == NULL || 4150 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4151 req->sym_out = req1.sym_out; 4152 req->defobj_out = req1.defobj_out; 4153 assert(req->defobj_out != NULL); 4154 } 4155 } 4156 4157 /* 4158 * Search the dynamic linker itself, and possibly resolve the 4159 * symbol from there. This is how the application links to 4160 * dynamic linker services such as dlopen. 4161 */ 4162 if (req->sym_out == NULL || 4163 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4164 res = symlook_obj(&req1, &obj_rtld); 4165 if (res == 0) { 4166 req->sym_out = req1.sym_out; 4167 req->defobj_out = req1.defobj_out; 4168 assert(req->defobj_out != NULL); 4169 } 4170 } 4171 4172 return (req->sym_out != NULL ? 0 : ESRCH); 4173 } 4174 4175 static int 4176 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4177 { 4178 const Elf_Sym *def; 4179 const Obj_Entry *defobj; 4180 const Objlist_Entry *elm; 4181 SymLook req1; 4182 int res; 4183 4184 def = NULL; 4185 defobj = NULL; 4186 STAILQ_FOREACH(elm, objlist, link) { 4187 if (donelist_check(dlp, elm->obj)) 4188 continue; 4189 symlook_init_from_req(&req1, req); 4190 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4191 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4192 def = req1.sym_out; 4193 defobj = req1.defobj_out; 4194 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4195 break; 4196 } 4197 } 4198 } 4199 if (def != NULL) { 4200 req->sym_out = def; 4201 req->defobj_out = defobj; 4202 return (0); 4203 } 4204 return (ESRCH); 4205 } 4206 4207 /* 4208 * Search the chain of DAGS cointed to by the given Needed_Entry 4209 * for a symbol of the given name. Each DAG is scanned completely 4210 * before advancing to the next one. Returns a pointer to the symbol, 4211 * or NULL if no definition was found. 4212 */ 4213 static int 4214 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4215 { 4216 const Elf_Sym *def; 4217 const Needed_Entry *n; 4218 const Obj_Entry *defobj; 4219 SymLook req1; 4220 int res; 4221 4222 def = NULL; 4223 defobj = NULL; 4224 symlook_init_from_req(&req1, req); 4225 for (n = needed; n != NULL; n = n->next) { 4226 if (n->obj == NULL || 4227 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4228 continue; 4229 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4230 def = req1.sym_out; 4231 defobj = req1.defobj_out; 4232 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4233 break; 4234 } 4235 } 4236 if (def != NULL) { 4237 req->sym_out = def; 4238 req->defobj_out = defobj; 4239 return (0); 4240 } 4241 return (ESRCH); 4242 } 4243 4244 /* 4245 * Search the symbol table of a single shared object for a symbol of 4246 * the given name and version, if requested. Returns a pointer to the 4247 * symbol, or NULL if no definition was found. If the object is 4248 * filter, return filtered symbol from filtee. 4249 * 4250 * The symbol's hash value is passed in for efficiency reasons; that 4251 * eliminates many recomputations of the hash value. 4252 */ 4253 int 4254 symlook_obj(SymLook *req, const Obj_Entry *obj) 4255 { 4256 DoneList donelist; 4257 SymLook req1; 4258 int flags, res, mres; 4259 4260 /* 4261 * If there is at least one valid hash at this point, we prefer to 4262 * use the faster GNU version if available. 4263 */ 4264 if (obj->valid_hash_gnu) 4265 mres = symlook_obj1_gnu(req, obj); 4266 else if (obj->valid_hash_sysv) 4267 mres = symlook_obj1_sysv(req, obj); 4268 else 4269 return (EINVAL); 4270 4271 if (mres == 0) { 4272 if (obj->needed_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_filtees, &donelist); 4278 if (res == 0) { 4279 req->sym_out = req1.sym_out; 4280 req->defobj_out = req1.defobj_out; 4281 } 4282 return (res); 4283 } 4284 if (obj->needed_aux_filtees != NULL) { 4285 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4286 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4287 donelist_init(&donelist); 4288 symlook_init_from_req(&req1, req); 4289 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4290 if (res == 0) { 4291 req->sym_out = req1.sym_out; 4292 req->defobj_out = req1.defobj_out; 4293 return (res); 4294 } 4295 } 4296 } 4297 return (mres); 4298 } 4299 4300 /* Symbol match routine common to both hash functions */ 4301 static bool 4302 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4303 const unsigned long symnum) 4304 { 4305 Elf_Versym verndx; 4306 const Elf_Sym *symp; 4307 const char *strp; 4308 4309 symp = obj->symtab + symnum; 4310 strp = obj->strtab + symp->st_name; 4311 4312 switch (ELF_ST_TYPE(symp->st_info)) { 4313 case STT_FUNC: 4314 case STT_NOTYPE: 4315 case STT_OBJECT: 4316 case STT_COMMON: 4317 case STT_GNU_IFUNC: 4318 if (symp->st_value == 0) 4319 return (false); 4320 /* fallthrough */ 4321 case STT_TLS: 4322 if (symp->st_shndx != SHN_UNDEF) 4323 break; 4324 #ifndef __mips__ 4325 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4326 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4327 break; 4328 #endif 4329 /* fallthrough */ 4330 default: 4331 return (false); 4332 } 4333 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4334 return (false); 4335 4336 if (req->ventry == NULL) { 4337 if (obj->versyms != NULL) { 4338 verndx = VER_NDX(obj->versyms[symnum]); 4339 if (verndx > obj->vernum) { 4340 _rtld_error( 4341 "%s: symbol %s references wrong version %d", 4342 obj->path, obj->strtab + symnum, verndx); 4343 return (false); 4344 } 4345 /* 4346 * If we are not called from dlsym (i.e. this 4347 * is a normal relocation from unversioned 4348 * binary), accept the symbol immediately if 4349 * it happens to have first version after this 4350 * shared object became versioned. Otherwise, 4351 * if symbol is versioned and not hidden, 4352 * remember it. If it is the only symbol with 4353 * this name exported by the shared object, it 4354 * will be returned as a match by the calling 4355 * function. If symbol is global (verndx < 2) 4356 * accept it unconditionally. 4357 */ 4358 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4359 verndx == VER_NDX_GIVEN) { 4360 result->sym_out = symp; 4361 return (true); 4362 } 4363 else if (verndx >= VER_NDX_GIVEN) { 4364 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4365 == 0) { 4366 if (result->vsymp == NULL) 4367 result->vsymp = symp; 4368 result->vcount++; 4369 } 4370 return (false); 4371 } 4372 } 4373 result->sym_out = symp; 4374 return (true); 4375 } 4376 if (obj->versyms == NULL) { 4377 if (object_match_name(obj, req->ventry->name)) { 4378 _rtld_error("%s: object %s should provide version %s " 4379 "for symbol %s", obj_rtld.path, obj->path, 4380 req->ventry->name, obj->strtab + symnum); 4381 return (false); 4382 } 4383 } else { 4384 verndx = VER_NDX(obj->versyms[symnum]); 4385 if (verndx > obj->vernum) { 4386 _rtld_error("%s: symbol %s references wrong version %d", 4387 obj->path, obj->strtab + symnum, verndx); 4388 return (false); 4389 } 4390 if (obj->vertab[verndx].hash != req->ventry->hash || 4391 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4392 /* 4393 * Version does not match. Look if this is a 4394 * global symbol and if it is not hidden. If 4395 * global symbol (verndx < 2) is available, 4396 * use it. Do not return symbol if we are 4397 * called by dlvsym, because dlvsym looks for 4398 * a specific version and default one is not 4399 * what dlvsym wants. 4400 */ 4401 if ((req->flags & SYMLOOK_DLSYM) || 4402 (verndx >= VER_NDX_GIVEN) || 4403 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4404 return (false); 4405 } 4406 } 4407 result->sym_out = symp; 4408 return (true); 4409 } 4410 4411 /* 4412 * Search for symbol using SysV hash function. 4413 * obj->buckets is known not to be NULL at this point; the test for this was 4414 * performed with the obj->valid_hash_sysv assignment. 4415 */ 4416 static int 4417 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4418 { 4419 unsigned long symnum; 4420 Sym_Match_Result matchres; 4421 4422 matchres.sym_out = NULL; 4423 matchres.vsymp = NULL; 4424 matchres.vcount = 0; 4425 4426 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4427 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4428 if (symnum >= obj->nchains) 4429 return (ESRCH); /* Bad object */ 4430 4431 if (matched_symbol(req, obj, &matchres, symnum)) { 4432 req->sym_out = matchres.sym_out; 4433 req->defobj_out = obj; 4434 return (0); 4435 } 4436 } 4437 if (matchres.vcount == 1) { 4438 req->sym_out = matchres.vsymp; 4439 req->defobj_out = obj; 4440 return (0); 4441 } 4442 return (ESRCH); 4443 } 4444 4445 /* Search for symbol using GNU hash function */ 4446 static int 4447 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4448 { 4449 Elf_Addr bloom_word; 4450 const Elf32_Word *hashval; 4451 Elf32_Word bucket; 4452 Sym_Match_Result matchres; 4453 unsigned int h1, h2; 4454 unsigned long symnum; 4455 4456 matchres.sym_out = NULL; 4457 matchres.vsymp = NULL; 4458 matchres.vcount = 0; 4459 4460 /* Pick right bitmask word from Bloom filter array */ 4461 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4462 obj->maskwords_bm_gnu]; 4463 4464 /* Calculate modulus word size of gnu hash and its derivative */ 4465 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4466 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4467 4468 /* Filter out the "definitely not in set" queries */ 4469 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4470 return (ESRCH); 4471 4472 /* Locate hash chain and corresponding value element*/ 4473 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4474 if (bucket == 0) 4475 return (ESRCH); 4476 hashval = &obj->chain_zero_gnu[bucket]; 4477 do { 4478 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4479 symnum = hashval - obj->chain_zero_gnu; 4480 if (matched_symbol(req, obj, &matchres, symnum)) { 4481 req->sym_out = matchres.sym_out; 4482 req->defobj_out = obj; 4483 return (0); 4484 } 4485 } 4486 } while ((*hashval++ & 1) == 0); 4487 if (matchres.vcount == 1) { 4488 req->sym_out = matchres.vsymp; 4489 req->defobj_out = obj; 4490 return (0); 4491 } 4492 return (ESRCH); 4493 } 4494 4495 static void 4496 trace_loaded_objects(Obj_Entry *obj) 4497 { 4498 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4499 int c; 4500 4501 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4502 main_local = ""; 4503 4504 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4505 fmt1 = "\t%o => %p (%x)\n"; 4506 4507 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4508 fmt2 = "\t%o (%x)\n"; 4509 4510 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4511 4512 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4513 Needed_Entry *needed; 4514 const char *name, *path; 4515 bool is_lib; 4516 4517 if (obj->marker) 4518 continue; 4519 if (list_containers && obj->needed != NULL) 4520 rtld_printf("%s:\n", obj->path); 4521 for (needed = obj->needed; needed; needed = needed->next) { 4522 if (needed->obj != NULL) { 4523 if (needed->obj->traced && !list_containers) 4524 continue; 4525 needed->obj->traced = true; 4526 path = needed->obj->path; 4527 } else 4528 path = "not found"; 4529 4530 name = obj->strtab + needed->name; 4531 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4532 4533 fmt = is_lib ? fmt1 : fmt2; 4534 while ((c = *fmt++) != '\0') { 4535 switch (c) { 4536 default: 4537 rtld_putchar(c); 4538 continue; 4539 case '\\': 4540 switch (c = *fmt) { 4541 case '\0': 4542 continue; 4543 case 'n': 4544 rtld_putchar('\n'); 4545 break; 4546 case 't': 4547 rtld_putchar('\t'); 4548 break; 4549 } 4550 break; 4551 case '%': 4552 switch (c = *fmt) { 4553 case '\0': 4554 continue; 4555 case '%': 4556 default: 4557 rtld_putchar(c); 4558 break; 4559 case 'A': 4560 rtld_putstr(main_local); 4561 break; 4562 case 'a': 4563 rtld_putstr(obj_main->path); 4564 break; 4565 case 'o': 4566 rtld_putstr(name); 4567 break; 4568 #if 0 4569 case 'm': 4570 rtld_printf("%d", sodp->sod_major); 4571 break; 4572 case 'n': 4573 rtld_printf("%d", sodp->sod_minor); 4574 break; 4575 #endif 4576 case 'p': 4577 rtld_putstr(path); 4578 break; 4579 case 'x': 4580 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4581 0); 4582 break; 4583 } 4584 break; 4585 } 4586 ++fmt; 4587 } 4588 } 4589 } 4590 } 4591 4592 /* 4593 * Unload a dlopened object and its dependencies from memory and from 4594 * our data structures. It is assumed that the DAG rooted in the 4595 * object has already been unreferenced, and that the object has a 4596 * reference count of 0. 4597 */ 4598 static void 4599 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4600 { 4601 Obj_Entry marker, *obj, *next; 4602 4603 assert(root->refcount == 0); 4604 4605 /* 4606 * Pass over the DAG removing unreferenced objects from 4607 * appropriate lists. 4608 */ 4609 unlink_object(root); 4610 4611 /* Unmap all objects that are no longer referenced. */ 4612 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4613 next = TAILQ_NEXT(obj, next); 4614 if (obj->marker || obj->refcount != 0) 4615 continue; 4616 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4617 obj->mapsize, 0, obj->path); 4618 dbg("unloading \"%s\"", obj->path); 4619 /* 4620 * Unlink the object now to prevent new references from 4621 * being acquired while the bind lock is dropped in 4622 * recursive dlclose() invocations. 4623 */ 4624 TAILQ_REMOVE(&obj_list, obj, next); 4625 obj_count--; 4626 4627 if (obj->filtees_loaded) { 4628 if (next != NULL) { 4629 init_marker(&marker); 4630 TAILQ_INSERT_BEFORE(next, &marker, next); 4631 unload_filtees(obj, lockstate); 4632 next = TAILQ_NEXT(&marker, next); 4633 TAILQ_REMOVE(&obj_list, &marker, next); 4634 } else 4635 unload_filtees(obj, lockstate); 4636 } 4637 release_object(obj); 4638 } 4639 } 4640 4641 static void 4642 unlink_object(Obj_Entry *root) 4643 { 4644 Objlist_Entry *elm; 4645 4646 if (root->refcount == 0) { 4647 /* Remove the object from the RTLD_GLOBAL list. */ 4648 objlist_remove(&list_global, root); 4649 4650 /* Remove the object from all objects' DAG lists. */ 4651 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4652 objlist_remove(&elm->obj->dldags, root); 4653 if (elm->obj != root) 4654 unlink_object(elm->obj); 4655 } 4656 } 4657 } 4658 4659 static void 4660 ref_dag(Obj_Entry *root) 4661 { 4662 Objlist_Entry *elm; 4663 4664 assert(root->dag_inited); 4665 STAILQ_FOREACH(elm, &root->dagmembers, link) 4666 elm->obj->refcount++; 4667 } 4668 4669 static void 4670 unref_dag(Obj_Entry *root) 4671 { 4672 Objlist_Entry *elm; 4673 4674 assert(root->dag_inited); 4675 STAILQ_FOREACH(elm, &root->dagmembers, link) 4676 elm->obj->refcount--; 4677 } 4678 4679 /* 4680 * Common code for MD __tls_get_addr(). 4681 */ 4682 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4683 static void * 4684 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4685 { 4686 Elf_Addr *newdtv, *dtv; 4687 RtldLockState lockstate; 4688 int to_copy; 4689 4690 dtv = *dtvp; 4691 /* Check dtv generation in case new modules have arrived */ 4692 if (dtv[0] != tls_dtv_generation) { 4693 wlock_acquire(rtld_bind_lock, &lockstate); 4694 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4695 to_copy = dtv[1]; 4696 if (to_copy > tls_max_index) 4697 to_copy = tls_max_index; 4698 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4699 newdtv[0] = tls_dtv_generation; 4700 newdtv[1] = tls_max_index; 4701 free(dtv); 4702 lock_release(rtld_bind_lock, &lockstate); 4703 dtv = *dtvp = newdtv; 4704 } 4705 4706 /* Dynamically allocate module TLS if necessary */ 4707 if (dtv[index + 1] == 0) { 4708 /* Signal safe, wlock will block out signals. */ 4709 wlock_acquire(rtld_bind_lock, &lockstate); 4710 if (!dtv[index + 1]) 4711 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4712 lock_release(rtld_bind_lock, &lockstate); 4713 } 4714 return ((void *)(dtv[index + 1] + offset)); 4715 } 4716 4717 void * 4718 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4719 { 4720 Elf_Addr *dtv; 4721 4722 dtv = *dtvp; 4723 /* Check dtv generation in case new modules have arrived */ 4724 if (__predict_true(dtv[0] == tls_dtv_generation && 4725 dtv[index + 1] != 0)) 4726 return ((void *)(dtv[index + 1] + offset)); 4727 return (tls_get_addr_slow(dtvp, index, offset)); 4728 } 4729 4730 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4731 defined(__powerpc__) || defined(__riscv) 4732 4733 /* 4734 * Return pointer to allocated TLS block 4735 */ 4736 static void * 4737 get_tls_block_ptr(void *tcb, size_t tcbsize) 4738 { 4739 size_t extra_size, post_size, pre_size, tls_block_size; 4740 size_t tls_init_align; 4741 4742 tls_init_align = MAX(obj_main->tlsalign, 1); 4743 4744 /* Compute fragments sizes. */ 4745 extra_size = tcbsize - TLS_TCB_SIZE; 4746 post_size = calculate_tls_post_size(tls_init_align); 4747 tls_block_size = tcbsize + post_size; 4748 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4749 4750 return ((char *)tcb - pre_size - extra_size); 4751 } 4752 4753 /* 4754 * Allocate Static TLS using the Variant I method. 4755 * 4756 * For details on the layout, see lib/libc/gen/tls.c. 4757 * 4758 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4759 * it is based on tls_last_offset, and TLS offsets here are really TCB 4760 * offsets, whereas libc's tls_static_space is just the executable's static 4761 * TLS segment. 4762 */ 4763 void * 4764 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4765 { 4766 Obj_Entry *obj; 4767 char *tls_block; 4768 Elf_Addr *dtv, **tcb; 4769 Elf_Addr addr; 4770 Elf_Addr i; 4771 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4772 size_t tls_init_align; 4773 4774 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4775 return (oldtcb); 4776 4777 assert(tcbsize >= TLS_TCB_SIZE); 4778 maxalign = MAX(tcbalign, tls_static_max_align); 4779 tls_init_align = MAX(obj_main->tlsalign, 1); 4780 4781 /* Compute fragmets sizes. */ 4782 extra_size = tcbsize - TLS_TCB_SIZE; 4783 post_size = calculate_tls_post_size(tls_init_align); 4784 tls_block_size = tcbsize + post_size; 4785 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4786 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4787 4788 /* Allocate whole TLS block */ 4789 tls_block = malloc_aligned(tls_block_size, maxalign); 4790 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4791 4792 if (oldtcb != NULL) { 4793 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4794 tls_static_space); 4795 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4796 4797 /* Adjust the DTV. */ 4798 dtv = tcb[0]; 4799 for (i = 0; i < dtv[1]; i++) { 4800 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4801 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4802 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4803 } 4804 } 4805 } else { 4806 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4807 tcb[0] = dtv; 4808 dtv[0] = tls_dtv_generation; 4809 dtv[1] = tls_max_index; 4810 4811 for (obj = globallist_curr(objs); obj != NULL; 4812 obj = globallist_next(obj)) { 4813 if (obj->tlsoffset > 0) { 4814 addr = (Elf_Addr)tcb + obj->tlsoffset; 4815 if (obj->tlsinitsize > 0) 4816 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4817 if (obj->tlssize > obj->tlsinitsize) 4818 memset((void*)(addr + obj->tlsinitsize), 0, 4819 obj->tlssize - obj->tlsinitsize); 4820 dtv[obj->tlsindex + 1] = addr; 4821 } 4822 } 4823 } 4824 4825 return (tcb); 4826 } 4827 4828 void 4829 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4830 { 4831 Elf_Addr *dtv; 4832 Elf_Addr tlsstart, tlsend; 4833 size_t post_size; 4834 size_t dtvsize, i, tls_init_align; 4835 4836 assert(tcbsize >= TLS_TCB_SIZE); 4837 tls_init_align = MAX(obj_main->tlsalign, 1); 4838 4839 /* Compute fragments sizes. */ 4840 post_size = calculate_tls_post_size(tls_init_align); 4841 4842 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4843 tlsend = (Elf_Addr)tcb + tls_static_space; 4844 4845 dtv = *(Elf_Addr **)tcb; 4846 dtvsize = dtv[1]; 4847 for (i = 0; i < dtvsize; i++) { 4848 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4849 free((void*)dtv[i+2]); 4850 } 4851 } 4852 free(dtv); 4853 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4854 } 4855 4856 #endif 4857 4858 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4859 4860 /* 4861 * Allocate Static TLS using the Variant II method. 4862 */ 4863 void * 4864 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4865 { 4866 Obj_Entry *obj; 4867 size_t size, ralign; 4868 char *tls; 4869 Elf_Addr *dtv, *olddtv; 4870 Elf_Addr segbase, oldsegbase, addr; 4871 size_t i; 4872 4873 ralign = tcbalign; 4874 if (tls_static_max_align > ralign) 4875 ralign = tls_static_max_align; 4876 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4877 4878 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4879 tls = malloc_aligned(size, ralign); 4880 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4881 4882 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4883 ((Elf_Addr*)segbase)[0] = segbase; 4884 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4885 4886 dtv[0] = tls_dtv_generation; 4887 dtv[1] = tls_max_index; 4888 4889 if (oldtls) { 4890 /* 4891 * Copy the static TLS block over whole. 4892 */ 4893 oldsegbase = (Elf_Addr) oldtls; 4894 memcpy((void *)(segbase - tls_static_space), 4895 (const void *)(oldsegbase - tls_static_space), 4896 tls_static_space); 4897 4898 /* 4899 * If any dynamic TLS blocks have been created tls_get_addr(), 4900 * move them over. 4901 */ 4902 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4903 for (i = 0; i < olddtv[1]; i++) { 4904 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4905 dtv[i+2] = olddtv[i+2]; 4906 olddtv[i+2] = 0; 4907 } 4908 } 4909 4910 /* 4911 * We assume that this block was the one we created with 4912 * allocate_initial_tls(). 4913 */ 4914 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4915 } else { 4916 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4917 if (obj->marker || obj->tlsoffset == 0) 4918 continue; 4919 addr = segbase - obj->tlsoffset; 4920 memset((void*)(addr + obj->tlsinitsize), 4921 0, obj->tlssize - obj->tlsinitsize); 4922 if (obj->tlsinit) 4923 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4924 dtv[obj->tlsindex + 1] = addr; 4925 } 4926 } 4927 4928 return (void*) segbase; 4929 } 4930 4931 void 4932 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4933 { 4934 Elf_Addr* dtv; 4935 size_t size, ralign; 4936 int dtvsize, i; 4937 Elf_Addr tlsstart, tlsend; 4938 4939 /* 4940 * Figure out the size of the initial TLS block so that we can 4941 * find stuff which ___tls_get_addr() allocated dynamically. 4942 */ 4943 ralign = tcbalign; 4944 if (tls_static_max_align > ralign) 4945 ralign = tls_static_max_align; 4946 size = round(tls_static_space, ralign); 4947 4948 dtv = ((Elf_Addr**)tls)[1]; 4949 dtvsize = dtv[1]; 4950 tlsend = (Elf_Addr) tls; 4951 tlsstart = tlsend - size; 4952 for (i = 0; i < dtvsize; i++) { 4953 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4954 free_aligned((void *)dtv[i + 2]); 4955 } 4956 } 4957 4958 free_aligned((void *)tlsstart); 4959 free((void*) dtv); 4960 } 4961 4962 #endif 4963 4964 /* 4965 * Allocate TLS block for module with given index. 4966 */ 4967 void * 4968 allocate_module_tls(int index) 4969 { 4970 Obj_Entry* obj; 4971 char* p; 4972 4973 TAILQ_FOREACH(obj, &obj_list, next) { 4974 if (obj->marker) 4975 continue; 4976 if (obj->tlsindex == index) 4977 break; 4978 } 4979 if (!obj) { 4980 _rtld_error("Can't find module with TLS index %d", index); 4981 rtld_die(); 4982 } 4983 4984 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4985 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4986 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4987 4988 return p; 4989 } 4990 4991 bool 4992 allocate_tls_offset(Obj_Entry *obj) 4993 { 4994 size_t off; 4995 4996 if (obj->tls_done) 4997 return true; 4998 4999 if (obj->tlssize == 0) { 5000 obj->tls_done = true; 5001 return true; 5002 } 5003 5004 if (tls_last_offset == 0) 5005 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5006 else 5007 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5008 obj->tlssize, obj->tlsalign); 5009 5010 /* 5011 * If we have already fixed the size of the static TLS block, we 5012 * must stay within that size. When allocating the static TLS, we 5013 * leave a small amount of space spare to be used for dynamically 5014 * loading modules which use static TLS. 5015 */ 5016 if (tls_static_space != 0) { 5017 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5018 return false; 5019 } else if (obj->tlsalign > tls_static_max_align) { 5020 tls_static_max_align = obj->tlsalign; 5021 } 5022 5023 tls_last_offset = obj->tlsoffset = off; 5024 tls_last_size = obj->tlssize; 5025 obj->tls_done = true; 5026 5027 return true; 5028 } 5029 5030 void 5031 free_tls_offset(Obj_Entry *obj) 5032 { 5033 5034 /* 5035 * If we were the last thing to allocate out of the static TLS 5036 * block, we give our space back to the 'allocator'. This is a 5037 * simplistic workaround to allow libGL.so.1 to be loaded and 5038 * unloaded multiple times. 5039 */ 5040 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5041 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5042 tls_last_offset -= obj->tlssize; 5043 tls_last_size = 0; 5044 } 5045 } 5046 5047 void * 5048 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5049 { 5050 void *ret; 5051 RtldLockState lockstate; 5052 5053 wlock_acquire(rtld_bind_lock, &lockstate); 5054 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5055 tcbsize, tcbalign); 5056 lock_release(rtld_bind_lock, &lockstate); 5057 return (ret); 5058 } 5059 5060 void 5061 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5062 { 5063 RtldLockState lockstate; 5064 5065 wlock_acquire(rtld_bind_lock, &lockstate); 5066 free_tls(tcb, tcbsize, tcbalign); 5067 lock_release(rtld_bind_lock, &lockstate); 5068 } 5069 5070 static void 5071 object_add_name(Obj_Entry *obj, const char *name) 5072 { 5073 Name_Entry *entry; 5074 size_t len; 5075 5076 len = strlen(name); 5077 entry = malloc(sizeof(Name_Entry) + len); 5078 5079 if (entry != NULL) { 5080 strcpy(entry->name, name); 5081 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5082 } 5083 } 5084 5085 static int 5086 object_match_name(const Obj_Entry *obj, const char *name) 5087 { 5088 Name_Entry *entry; 5089 5090 STAILQ_FOREACH(entry, &obj->names, link) { 5091 if (strcmp(name, entry->name) == 0) 5092 return (1); 5093 } 5094 return (0); 5095 } 5096 5097 static Obj_Entry * 5098 locate_dependency(const Obj_Entry *obj, const char *name) 5099 { 5100 const Objlist_Entry *entry; 5101 const Needed_Entry *needed; 5102 5103 STAILQ_FOREACH(entry, &list_main, link) { 5104 if (object_match_name(entry->obj, name)) 5105 return entry->obj; 5106 } 5107 5108 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5109 if (strcmp(obj->strtab + needed->name, name) == 0 || 5110 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5111 /* 5112 * If there is DT_NEEDED for the name we are looking for, 5113 * we are all set. Note that object might not be found if 5114 * dependency was not loaded yet, so the function can 5115 * return NULL here. This is expected and handled 5116 * properly by the caller. 5117 */ 5118 return (needed->obj); 5119 } 5120 } 5121 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5122 obj->path, name); 5123 rtld_die(); 5124 } 5125 5126 static int 5127 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5128 const Elf_Vernaux *vna) 5129 { 5130 const Elf_Verdef *vd; 5131 const char *vername; 5132 5133 vername = refobj->strtab + vna->vna_name; 5134 vd = depobj->verdef; 5135 if (vd == NULL) { 5136 _rtld_error("%s: version %s required by %s not defined", 5137 depobj->path, vername, refobj->path); 5138 return (-1); 5139 } 5140 for (;;) { 5141 if (vd->vd_version != VER_DEF_CURRENT) { 5142 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5143 depobj->path, vd->vd_version); 5144 return (-1); 5145 } 5146 if (vna->vna_hash == vd->vd_hash) { 5147 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5148 ((const char *)vd + vd->vd_aux); 5149 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5150 return (0); 5151 } 5152 if (vd->vd_next == 0) 5153 break; 5154 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5155 } 5156 if (vna->vna_flags & VER_FLG_WEAK) 5157 return (0); 5158 _rtld_error("%s: version %s required by %s not found", 5159 depobj->path, vername, refobj->path); 5160 return (-1); 5161 } 5162 5163 static int 5164 rtld_verify_object_versions(Obj_Entry *obj) 5165 { 5166 const Elf_Verneed *vn; 5167 const Elf_Verdef *vd; 5168 const Elf_Verdaux *vda; 5169 const Elf_Vernaux *vna; 5170 const Obj_Entry *depobj; 5171 int maxvernum, vernum; 5172 5173 if (obj->ver_checked) 5174 return (0); 5175 obj->ver_checked = true; 5176 5177 maxvernum = 0; 5178 /* 5179 * Walk over defined and required version records and figure out 5180 * max index used by any of them. Do very basic sanity checking 5181 * while there. 5182 */ 5183 vn = obj->verneed; 5184 while (vn != NULL) { 5185 if (vn->vn_version != VER_NEED_CURRENT) { 5186 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5187 obj->path, vn->vn_version); 5188 return (-1); 5189 } 5190 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5191 for (;;) { 5192 vernum = VER_NEED_IDX(vna->vna_other); 5193 if (vernum > maxvernum) 5194 maxvernum = vernum; 5195 if (vna->vna_next == 0) 5196 break; 5197 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5198 } 5199 if (vn->vn_next == 0) 5200 break; 5201 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5202 } 5203 5204 vd = obj->verdef; 5205 while (vd != NULL) { 5206 if (vd->vd_version != VER_DEF_CURRENT) { 5207 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5208 obj->path, vd->vd_version); 5209 return (-1); 5210 } 5211 vernum = VER_DEF_IDX(vd->vd_ndx); 5212 if (vernum > maxvernum) 5213 maxvernum = vernum; 5214 if (vd->vd_next == 0) 5215 break; 5216 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5217 } 5218 5219 if (maxvernum == 0) 5220 return (0); 5221 5222 /* 5223 * Store version information in array indexable by version index. 5224 * Verify that object version requirements are satisfied along the 5225 * way. 5226 */ 5227 obj->vernum = maxvernum + 1; 5228 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5229 5230 vd = obj->verdef; 5231 while (vd != NULL) { 5232 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5233 vernum = VER_DEF_IDX(vd->vd_ndx); 5234 assert(vernum <= maxvernum); 5235 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5236 obj->vertab[vernum].hash = vd->vd_hash; 5237 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5238 obj->vertab[vernum].file = NULL; 5239 obj->vertab[vernum].flags = 0; 5240 } 5241 if (vd->vd_next == 0) 5242 break; 5243 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5244 } 5245 5246 vn = obj->verneed; 5247 while (vn != NULL) { 5248 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5249 if (depobj == NULL) 5250 return (-1); 5251 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5252 for (;;) { 5253 if (check_object_provided_version(obj, depobj, vna)) 5254 return (-1); 5255 vernum = VER_NEED_IDX(vna->vna_other); 5256 assert(vernum <= maxvernum); 5257 obj->vertab[vernum].hash = vna->vna_hash; 5258 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5259 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5260 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5261 VER_INFO_HIDDEN : 0; 5262 if (vna->vna_next == 0) 5263 break; 5264 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5265 } 5266 if (vn->vn_next == 0) 5267 break; 5268 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5269 } 5270 return 0; 5271 } 5272 5273 static int 5274 rtld_verify_versions(const Objlist *objlist) 5275 { 5276 Objlist_Entry *entry; 5277 int rc; 5278 5279 rc = 0; 5280 STAILQ_FOREACH(entry, objlist, link) { 5281 /* 5282 * Skip dummy objects or objects that have their version requirements 5283 * already checked. 5284 */ 5285 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5286 continue; 5287 if (rtld_verify_object_versions(entry->obj) == -1) { 5288 rc = -1; 5289 if (ld_tracing == NULL) 5290 break; 5291 } 5292 } 5293 if (rc == 0 || ld_tracing != NULL) 5294 rc = rtld_verify_object_versions(&obj_rtld); 5295 return rc; 5296 } 5297 5298 const Ver_Entry * 5299 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5300 { 5301 Elf_Versym vernum; 5302 5303 if (obj->vertab) { 5304 vernum = VER_NDX(obj->versyms[symnum]); 5305 if (vernum >= obj->vernum) { 5306 _rtld_error("%s: symbol %s has wrong verneed value %d", 5307 obj->path, obj->strtab + symnum, vernum); 5308 } else if (obj->vertab[vernum].hash != 0) { 5309 return &obj->vertab[vernum]; 5310 } 5311 } 5312 return NULL; 5313 } 5314 5315 int 5316 _rtld_get_stack_prot(void) 5317 { 5318 5319 return (stack_prot); 5320 } 5321 5322 int 5323 _rtld_is_dlopened(void *arg) 5324 { 5325 Obj_Entry *obj; 5326 RtldLockState lockstate; 5327 int res; 5328 5329 rlock_acquire(rtld_bind_lock, &lockstate); 5330 obj = dlcheck(arg); 5331 if (obj == NULL) 5332 obj = obj_from_addr(arg); 5333 if (obj == NULL) { 5334 _rtld_error("No shared object contains address"); 5335 lock_release(rtld_bind_lock, &lockstate); 5336 return (-1); 5337 } 5338 res = obj->dlopened ? 1 : 0; 5339 lock_release(rtld_bind_lock, &lockstate); 5340 return (res); 5341 } 5342 5343 int 5344 obj_enforce_relro(Obj_Entry *obj) 5345 { 5346 5347 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5348 PROT_READ) == -1) { 5349 _rtld_error("%s: Cannot enforce relro protection: %s", 5350 obj->path, rtld_strerror(errno)); 5351 return (-1); 5352 } 5353 return (0); 5354 } 5355 5356 static void 5357 map_stacks_exec(RtldLockState *lockstate) 5358 { 5359 void (*thr_map_stacks_exec)(void); 5360 5361 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5362 return; 5363 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5364 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5365 if (thr_map_stacks_exec != NULL) { 5366 stack_prot |= PROT_EXEC; 5367 thr_map_stacks_exec(); 5368 } 5369 } 5370 5371 void 5372 symlook_init(SymLook *dst, const char *name) 5373 { 5374 5375 bzero(dst, sizeof(*dst)); 5376 dst->name = name; 5377 dst->hash = elf_hash(name); 5378 dst->hash_gnu = gnu_hash(name); 5379 } 5380 5381 static void 5382 symlook_init_from_req(SymLook *dst, const SymLook *src) 5383 { 5384 5385 dst->name = src->name; 5386 dst->hash = src->hash; 5387 dst->hash_gnu = src->hash_gnu; 5388 dst->ventry = src->ventry; 5389 dst->flags = src->flags; 5390 dst->defobj_out = NULL; 5391 dst->sym_out = NULL; 5392 dst->lockstate = src->lockstate; 5393 } 5394 5395 static int 5396 open_binary_fd(const char *argv0, bool search_in_path) 5397 { 5398 char *pathenv, *pe, binpath[PATH_MAX]; 5399 int fd; 5400 5401 if (search_in_path && strchr(argv0, '/') == NULL) { 5402 pathenv = getenv("PATH"); 5403 if (pathenv == NULL) { 5404 _rtld_error("-p and no PATH environment variable"); 5405 rtld_die(); 5406 } 5407 pathenv = strdup(pathenv); 5408 if (pathenv == NULL) { 5409 _rtld_error("Cannot allocate memory"); 5410 rtld_die(); 5411 } 5412 fd = -1; 5413 errno = ENOENT; 5414 while ((pe = strsep(&pathenv, ":")) != NULL) { 5415 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5416 sizeof(binpath)) 5417 continue; 5418 if (binpath[0] != '\0' && 5419 strlcat(binpath, "/", sizeof(binpath)) >= 5420 sizeof(binpath)) 5421 continue; 5422 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5423 sizeof(binpath)) 5424 continue; 5425 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5426 if (fd != -1 || errno != ENOENT) 5427 break; 5428 } 5429 free(pathenv); 5430 } else { 5431 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5432 } 5433 5434 if (fd == -1) { 5435 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5436 rtld_die(); 5437 } 5438 return (fd); 5439 } 5440 5441 /* 5442 * Parse a set of command-line arguments. 5443 */ 5444 static int 5445 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5446 { 5447 const char *arg; 5448 int fd, i, j, arglen; 5449 char opt; 5450 5451 dbg("Parsing command-line arguments"); 5452 *use_pathp = false; 5453 *fdp = -1; 5454 5455 for (i = 1; i < argc; i++ ) { 5456 arg = argv[i]; 5457 dbg("argv[%d]: '%s'", i, arg); 5458 5459 /* 5460 * rtld arguments end with an explicit "--" or with the first 5461 * non-prefixed argument. 5462 */ 5463 if (strcmp(arg, "--") == 0) { 5464 i++; 5465 break; 5466 } 5467 if (arg[0] != '-') 5468 break; 5469 5470 /* 5471 * All other arguments are single-character options that can 5472 * be combined, so we need to search through `arg` for them. 5473 */ 5474 arglen = strlen(arg); 5475 for (j = 1; j < arglen; j++) { 5476 opt = arg[j]; 5477 if (opt == 'h') { 5478 print_usage(argv[0]); 5479 _exit(0); 5480 } else if (opt == 'f') { 5481 /* 5482 * -f XX can be used to specify a descriptor for the 5483 * binary named at the command line (i.e., the later 5484 * argument will specify the process name but the 5485 * descriptor is what will actually be executed) 5486 */ 5487 if (j != arglen - 1) { 5488 /* -f must be the last option in, e.g., -abcf */ 5489 _rtld_error("Invalid options: %s", arg); 5490 rtld_die(); 5491 } 5492 i++; 5493 fd = parse_integer(argv[i]); 5494 if (fd == -1) { 5495 _rtld_error("Invalid file descriptor: '%s'", 5496 argv[i]); 5497 rtld_die(); 5498 } 5499 *fdp = fd; 5500 break; 5501 } else if (opt == 'p') { 5502 *use_pathp = true; 5503 } else { 5504 _rtld_error("Invalid argument: '%s'", arg); 5505 print_usage(argv[0]); 5506 rtld_die(); 5507 } 5508 } 5509 } 5510 5511 return (i); 5512 } 5513 5514 /* 5515 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5516 */ 5517 static int 5518 parse_integer(const char *str) 5519 { 5520 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5521 const char *orig; 5522 int n; 5523 char c; 5524 5525 orig = str; 5526 n = 0; 5527 for (c = *str; c != '\0'; c = *++str) { 5528 if (c < '0' || c > '9') 5529 return (-1); 5530 5531 n *= RADIX; 5532 n += c - '0'; 5533 } 5534 5535 /* Make sure we actually parsed something. */ 5536 if (str == orig) 5537 return (-1); 5538 return (n); 5539 } 5540 5541 static void 5542 print_usage(const char *argv0) 5543 { 5544 5545 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5546 "\n" 5547 "Options:\n" 5548 " -h Display this help message\n" 5549 " -p Search in PATH for named binary\n" 5550 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5551 " -- End of RTLD options\n" 5552 " <binary> Name of process to execute\n" 5553 " <args> Arguments to the executed process\n", argv0); 5554 } 5555 5556 /* 5557 * Overrides for libc_pic-provided functions. 5558 */ 5559 5560 int 5561 __getosreldate(void) 5562 { 5563 size_t len; 5564 int oid[2]; 5565 int error, osrel; 5566 5567 if (osreldate != 0) 5568 return (osreldate); 5569 5570 oid[0] = CTL_KERN; 5571 oid[1] = KERN_OSRELDATE; 5572 osrel = 0; 5573 len = sizeof(osrel); 5574 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5575 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5576 osreldate = osrel; 5577 return (osreldate); 5578 } 5579 5580 void 5581 exit(int status) 5582 { 5583 5584 _exit(status); 5585 } 5586 5587 void (*__cleanup)(void); 5588 int __isthreaded = 0; 5589 int _thread_autoinit_dummy_decl = 1; 5590 5591 /* 5592 * No unresolved symbols for rtld. 5593 */ 5594 void 5595 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5596 { 5597 } 5598 5599 const char * 5600 rtld_strerror(int errnum) 5601 { 5602 5603 if (errnum < 0 || errnum >= sys_nerr) 5604 return ("Unknown error"); 5605 return (sys_errlist[errnum]); 5606 } 5607