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 /* 713 * Setup TLS for main thread. This must be done after the 714 * relocations are processed, since tls initialization section 715 * might be the subject for relocations. 716 */ 717 dbg("initializing initial thread local storage"); 718 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 719 720 dbg("initializing key program variables"); 721 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 722 set_program_var("environ", env); 723 set_program_var("__elf_aux_vector", aux); 724 725 /* Make a list of init functions to call. */ 726 objlist_init(&initlist); 727 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 728 preload_tail, &initlist); 729 730 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 731 732 map_stacks_exec(NULL); 733 ifunc_init(aux); 734 735 dbg("resolving ifuncs"); 736 if (resolve_objects_ifunc(obj_main, 737 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 738 NULL) == -1) 739 rtld_die(); 740 741 if (!obj_main->crt_no_init) { 742 /* 743 * Make sure we don't call the main program's init and fini 744 * functions for binaries linked with old crt1 which calls 745 * _init itself. 746 */ 747 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 748 obj_main->preinit_array = obj_main->init_array = 749 obj_main->fini_array = (Elf_Addr)NULL; 750 } 751 752 /* 753 * Execute MD initializers required before we call the objects' 754 * init functions. 755 */ 756 pre_init(); 757 758 wlock_acquire(rtld_bind_lock, &lockstate); 759 if (obj_main->crt_no_init) 760 preinit_main(); 761 objlist_call_init(&initlist, &lockstate); 762 _r_debug_postinit(&obj_main->linkmap); 763 objlist_clear(&initlist); 764 dbg("loading filtees"); 765 TAILQ_FOREACH(obj, &obj_list, next) { 766 if (obj->marker) 767 continue; 768 if (ld_loadfltr || obj->z_loadfltr) 769 load_filtees(obj, 0, &lockstate); 770 } 771 lock_release(rtld_bind_lock, &lockstate); 772 773 dbg("transferring control to program entry point = %p", obj_main->entry); 774 775 /* Return the exit procedure and the program entry point. */ 776 *exit_proc = rtld_exit; 777 *objp = obj_main; 778 return (func_ptr_type) obj_main->entry; 779 } 780 781 void * 782 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 783 { 784 void *ptr; 785 Elf_Addr target; 786 787 ptr = (void *)make_function_pointer(def, obj); 788 target = call_ifunc_resolver(ptr); 789 return ((void *)target); 790 } 791 792 /* 793 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 794 * Changes to this function should be applied there as well. 795 */ 796 Elf_Addr 797 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 798 { 799 const Elf_Rel *rel; 800 const Elf_Sym *def; 801 const Obj_Entry *defobj; 802 Elf_Addr *where; 803 Elf_Addr target; 804 RtldLockState lockstate; 805 806 rlock_acquire(rtld_bind_lock, &lockstate); 807 if (sigsetjmp(lockstate.env, 0) != 0) 808 lock_upgrade(rtld_bind_lock, &lockstate); 809 if (obj->pltrel) 810 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 811 else 812 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 813 814 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 815 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 816 NULL, &lockstate); 817 if (def == NULL) 818 rtld_die(); 819 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 820 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 821 else 822 target = (Elf_Addr)(defobj->relocbase + def->st_value); 823 824 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 825 defobj->strtab + def->st_name, basename(obj->path), 826 (void *)target, basename(defobj->path)); 827 828 /* 829 * Write the new contents for the jmpslot. Note that depending on 830 * architecture, the value which we need to return back to the 831 * lazy binding trampoline may or may not be the target 832 * address. The value returned from reloc_jmpslot() is the value 833 * that the trampoline needs. 834 */ 835 target = reloc_jmpslot(where, target, defobj, obj, rel); 836 lock_release(rtld_bind_lock, &lockstate); 837 return target; 838 } 839 840 /* 841 * Error reporting function. Use it like printf. If formats the message 842 * into a buffer, and sets things up so that the next call to dlerror() 843 * will return the message. 844 */ 845 void 846 _rtld_error(const char *fmt, ...) 847 { 848 static char buf[512]; 849 va_list ap; 850 851 va_start(ap, fmt); 852 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 853 error_message = buf; 854 va_end(ap); 855 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 856 } 857 858 /* 859 * Return a dynamically-allocated copy of the current error message, if any. 860 */ 861 static char * 862 errmsg_save(void) 863 { 864 return error_message == NULL ? NULL : xstrdup(error_message); 865 } 866 867 /* 868 * Restore the current error message from a copy which was previously saved 869 * by errmsg_save(). The copy is freed. 870 */ 871 static void 872 errmsg_restore(char *saved_msg) 873 { 874 if (saved_msg == NULL) 875 error_message = NULL; 876 else { 877 _rtld_error("%s", saved_msg); 878 free(saved_msg); 879 } 880 } 881 882 static const char * 883 basename(const char *name) 884 { 885 const char *p = strrchr(name, '/'); 886 return p != NULL ? p + 1 : name; 887 } 888 889 static struct utsname uts; 890 891 static char * 892 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 893 const char *subst, bool may_free) 894 { 895 char *p, *p1, *res, *resp; 896 int subst_len, kw_len, subst_count, old_len, new_len; 897 898 kw_len = strlen(kw); 899 900 /* 901 * First, count the number of the keyword occurrences, to 902 * preallocate the final string. 903 */ 904 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 905 p1 = strstr(p, kw); 906 if (p1 == NULL) 907 break; 908 } 909 910 /* 911 * If the keyword is not found, just return. 912 * 913 * Return non-substituted string if resolution failed. We 914 * cannot do anything more reasonable, the failure mode of the 915 * caller is unresolved library anyway. 916 */ 917 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 918 return (may_free ? real : xstrdup(real)); 919 if (obj != NULL) 920 subst = obj->origin_path; 921 922 /* 923 * There is indeed something to substitute. Calculate the 924 * length of the resulting string, and allocate it. 925 */ 926 subst_len = strlen(subst); 927 old_len = strlen(real); 928 new_len = old_len + (subst_len - kw_len) * subst_count; 929 res = xmalloc(new_len + 1); 930 931 /* 932 * Now, execute the substitution loop. 933 */ 934 for (p = real, resp = res, *resp = '\0';;) { 935 p1 = strstr(p, kw); 936 if (p1 != NULL) { 937 /* Copy the prefix before keyword. */ 938 memcpy(resp, p, p1 - p); 939 resp += p1 - p; 940 /* Keyword replacement. */ 941 memcpy(resp, subst, subst_len); 942 resp += subst_len; 943 *resp = '\0'; 944 p = p1 + kw_len; 945 } else 946 break; 947 } 948 949 /* Copy to the end of string and finish. */ 950 strcat(resp, p); 951 if (may_free) 952 free(real); 953 return (res); 954 } 955 956 static char * 957 origin_subst(Obj_Entry *obj, const char *real) 958 { 959 char *res1, *res2, *res3, *res4; 960 961 if (obj == NULL || !trust) 962 return (xstrdup(real)); 963 if (uts.sysname[0] == '\0') { 964 if (uname(&uts) != 0) { 965 _rtld_error("utsname failed: %d", errno); 966 return (NULL); 967 } 968 } 969 /* __DECONST is safe here since without may_free real is unchanged */ 970 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 971 false); 972 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 973 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 974 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 975 return (res4); 976 } 977 978 void 979 rtld_die(void) 980 { 981 const char *msg = dlerror(); 982 983 if (msg == NULL) 984 msg = "Fatal error"; 985 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 986 rtld_fdputstr(STDERR_FILENO, msg); 987 rtld_fdputchar(STDERR_FILENO, '\n'); 988 _exit(1); 989 } 990 991 /* 992 * Process a shared object's DYNAMIC section, and save the important 993 * information in its Obj_Entry structure. 994 */ 995 static void 996 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 997 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 998 { 999 const Elf_Dyn *dynp; 1000 Needed_Entry **needed_tail = &obj->needed; 1001 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1002 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1003 const Elf_Hashelt *hashtab; 1004 const Elf32_Word *hashval; 1005 Elf32_Word bkt, nmaskwords; 1006 int bloom_size32; 1007 int plttype = DT_REL; 1008 1009 *dyn_rpath = NULL; 1010 *dyn_soname = NULL; 1011 *dyn_runpath = NULL; 1012 1013 obj->bind_now = false; 1014 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1015 switch (dynp->d_tag) { 1016 1017 case DT_REL: 1018 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1019 break; 1020 1021 case DT_RELSZ: 1022 obj->relsize = dynp->d_un.d_val; 1023 break; 1024 1025 case DT_RELENT: 1026 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1027 break; 1028 1029 case DT_JMPREL: 1030 obj->pltrel = (const Elf_Rel *) 1031 (obj->relocbase + dynp->d_un.d_ptr); 1032 break; 1033 1034 case DT_PLTRELSZ: 1035 obj->pltrelsize = dynp->d_un.d_val; 1036 break; 1037 1038 case DT_RELA: 1039 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1040 break; 1041 1042 case DT_RELASZ: 1043 obj->relasize = dynp->d_un.d_val; 1044 break; 1045 1046 case DT_RELAENT: 1047 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1048 break; 1049 1050 case DT_PLTREL: 1051 plttype = dynp->d_un.d_val; 1052 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1053 break; 1054 1055 case DT_SYMTAB: 1056 obj->symtab = (const Elf_Sym *) 1057 (obj->relocbase + dynp->d_un.d_ptr); 1058 break; 1059 1060 case DT_SYMENT: 1061 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1062 break; 1063 1064 case DT_STRTAB: 1065 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1066 break; 1067 1068 case DT_STRSZ: 1069 obj->strsize = dynp->d_un.d_val; 1070 break; 1071 1072 case DT_VERNEED: 1073 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1074 dynp->d_un.d_val); 1075 break; 1076 1077 case DT_VERNEEDNUM: 1078 obj->verneednum = dynp->d_un.d_val; 1079 break; 1080 1081 case DT_VERDEF: 1082 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1083 dynp->d_un.d_val); 1084 break; 1085 1086 case DT_VERDEFNUM: 1087 obj->verdefnum = dynp->d_un.d_val; 1088 break; 1089 1090 case DT_VERSYM: 1091 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1092 dynp->d_un.d_val); 1093 break; 1094 1095 case DT_HASH: 1096 { 1097 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1098 dynp->d_un.d_ptr); 1099 obj->nbuckets = hashtab[0]; 1100 obj->nchains = hashtab[1]; 1101 obj->buckets = hashtab + 2; 1102 obj->chains = obj->buckets + obj->nbuckets; 1103 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1104 obj->buckets != NULL; 1105 } 1106 break; 1107 1108 case DT_GNU_HASH: 1109 { 1110 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1111 dynp->d_un.d_ptr); 1112 obj->nbuckets_gnu = hashtab[0]; 1113 obj->symndx_gnu = hashtab[1]; 1114 nmaskwords = hashtab[2]; 1115 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1116 obj->maskwords_bm_gnu = nmaskwords - 1; 1117 obj->shift2_gnu = hashtab[3]; 1118 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1119 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1120 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1121 obj->symndx_gnu; 1122 /* Number of bitmask words is required to be power of 2 */ 1123 obj->valid_hash_gnu = powerof2(nmaskwords) && 1124 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1125 } 1126 break; 1127 1128 case DT_NEEDED: 1129 if (!obj->rtld) { 1130 Needed_Entry *nep = NEW(Needed_Entry); 1131 nep->name = dynp->d_un.d_val; 1132 nep->obj = NULL; 1133 nep->next = NULL; 1134 1135 *needed_tail = nep; 1136 needed_tail = &nep->next; 1137 } 1138 break; 1139 1140 case DT_FILTER: 1141 if (!obj->rtld) { 1142 Needed_Entry *nep = NEW(Needed_Entry); 1143 nep->name = dynp->d_un.d_val; 1144 nep->obj = NULL; 1145 nep->next = NULL; 1146 1147 *needed_filtees_tail = nep; 1148 needed_filtees_tail = &nep->next; 1149 } 1150 break; 1151 1152 case DT_AUXILIARY: 1153 if (!obj->rtld) { 1154 Needed_Entry *nep = NEW(Needed_Entry); 1155 nep->name = dynp->d_un.d_val; 1156 nep->obj = NULL; 1157 nep->next = NULL; 1158 1159 *needed_aux_filtees_tail = nep; 1160 needed_aux_filtees_tail = &nep->next; 1161 } 1162 break; 1163 1164 case DT_PLTGOT: 1165 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1166 break; 1167 1168 case DT_TEXTREL: 1169 obj->textrel = true; 1170 break; 1171 1172 case DT_SYMBOLIC: 1173 obj->symbolic = true; 1174 break; 1175 1176 case DT_RPATH: 1177 /* 1178 * We have to wait until later to process this, because we 1179 * might not have gotten the address of the string table yet. 1180 */ 1181 *dyn_rpath = dynp; 1182 break; 1183 1184 case DT_SONAME: 1185 *dyn_soname = dynp; 1186 break; 1187 1188 case DT_RUNPATH: 1189 *dyn_runpath = dynp; 1190 break; 1191 1192 case DT_INIT: 1193 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1194 break; 1195 1196 case DT_PREINIT_ARRAY: 1197 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1198 break; 1199 1200 case DT_PREINIT_ARRAYSZ: 1201 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1202 break; 1203 1204 case DT_INIT_ARRAY: 1205 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1206 break; 1207 1208 case DT_INIT_ARRAYSZ: 1209 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1210 break; 1211 1212 case DT_FINI: 1213 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1214 break; 1215 1216 case DT_FINI_ARRAY: 1217 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1218 break; 1219 1220 case DT_FINI_ARRAYSZ: 1221 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1222 break; 1223 1224 /* 1225 * Don't process DT_DEBUG on MIPS as the dynamic section 1226 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1227 */ 1228 1229 #ifndef __mips__ 1230 case DT_DEBUG: 1231 if (!early) 1232 dbg("Filling in DT_DEBUG entry"); 1233 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1234 break; 1235 #endif 1236 1237 case DT_FLAGS: 1238 if (dynp->d_un.d_val & DF_ORIGIN) 1239 obj->z_origin = true; 1240 if (dynp->d_un.d_val & DF_SYMBOLIC) 1241 obj->symbolic = true; 1242 if (dynp->d_un.d_val & DF_TEXTREL) 1243 obj->textrel = true; 1244 if (dynp->d_un.d_val & DF_BIND_NOW) 1245 obj->bind_now = true; 1246 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1247 ;*/ 1248 break; 1249 #ifdef __mips__ 1250 case DT_MIPS_LOCAL_GOTNO: 1251 obj->local_gotno = dynp->d_un.d_val; 1252 break; 1253 1254 case DT_MIPS_SYMTABNO: 1255 obj->symtabno = dynp->d_un.d_val; 1256 break; 1257 1258 case DT_MIPS_GOTSYM: 1259 obj->gotsym = dynp->d_un.d_val; 1260 break; 1261 1262 case DT_MIPS_RLD_MAP: 1263 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1264 break; 1265 1266 case DT_MIPS_PLTGOT: 1267 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1268 dynp->d_un.d_ptr); 1269 break; 1270 1271 #endif 1272 1273 #ifdef __powerpc64__ 1274 case DT_PPC64_GLINK: 1275 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1276 break; 1277 #endif 1278 1279 case DT_FLAGS_1: 1280 if (dynp->d_un.d_val & DF_1_NOOPEN) 1281 obj->z_noopen = true; 1282 if (dynp->d_un.d_val & DF_1_ORIGIN) 1283 obj->z_origin = true; 1284 if (dynp->d_un.d_val & DF_1_GLOBAL) 1285 obj->z_global = true; 1286 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1287 obj->bind_now = true; 1288 if (dynp->d_un.d_val & DF_1_NODELETE) 1289 obj->z_nodelete = true; 1290 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1291 obj->z_loadfltr = true; 1292 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1293 obj->z_interpose = true; 1294 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1295 obj->z_nodeflib = true; 1296 break; 1297 1298 default: 1299 if (!early) { 1300 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1301 (long)dynp->d_tag); 1302 } 1303 break; 1304 } 1305 } 1306 1307 obj->traced = false; 1308 1309 if (plttype == DT_RELA) { 1310 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1311 obj->pltrel = NULL; 1312 obj->pltrelasize = obj->pltrelsize; 1313 obj->pltrelsize = 0; 1314 } 1315 1316 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1317 if (obj->valid_hash_sysv) 1318 obj->dynsymcount = obj->nchains; 1319 else if (obj->valid_hash_gnu) { 1320 obj->dynsymcount = 0; 1321 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1322 if (obj->buckets_gnu[bkt] == 0) 1323 continue; 1324 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1325 do 1326 obj->dynsymcount++; 1327 while ((*hashval++ & 1u) == 0); 1328 } 1329 obj->dynsymcount += obj->symndx_gnu; 1330 } 1331 } 1332 1333 static bool 1334 obj_resolve_origin(Obj_Entry *obj) 1335 { 1336 1337 if (obj->origin_path != NULL) 1338 return (true); 1339 obj->origin_path = xmalloc(PATH_MAX); 1340 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1341 } 1342 1343 static void 1344 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1345 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1346 { 1347 1348 if (obj->z_origin && !obj_resolve_origin(obj)) 1349 rtld_die(); 1350 1351 if (dyn_runpath != NULL) { 1352 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1353 obj->runpath = origin_subst(obj, obj->runpath); 1354 } else if (dyn_rpath != NULL) { 1355 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1356 obj->rpath = origin_subst(obj, obj->rpath); 1357 } 1358 if (dyn_soname != NULL) 1359 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1360 } 1361 1362 static void 1363 digest_dynamic(Obj_Entry *obj, int early) 1364 { 1365 const Elf_Dyn *dyn_rpath; 1366 const Elf_Dyn *dyn_soname; 1367 const Elf_Dyn *dyn_runpath; 1368 1369 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1370 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1371 } 1372 1373 /* 1374 * Process a shared object's program header. This is used only for the 1375 * main program, when the kernel has already loaded the main program 1376 * into memory before calling the dynamic linker. It creates and 1377 * returns an Obj_Entry structure. 1378 */ 1379 static Obj_Entry * 1380 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1381 { 1382 Obj_Entry *obj; 1383 const Elf_Phdr *phlimit = phdr + phnum; 1384 const Elf_Phdr *ph; 1385 Elf_Addr note_start, note_end; 1386 int nsegs = 0; 1387 1388 obj = obj_new(); 1389 for (ph = phdr; ph < phlimit; ph++) { 1390 if (ph->p_type != PT_PHDR) 1391 continue; 1392 1393 obj->phdr = phdr; 1394 obj->phsize = ph->p_memsz; 1395 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1396 break; 1397 } 1398 1399 obj->stack_flags = PF_X | PF_R | PF_W; 1400 1401 for (ph = phdr; ph < phlimit; ph++) { 1402 switch (ph->p_type) { 1403 1404 case PT_INTERP: 1405 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1406 break; 1407 1408 case PT_LOAD: 1409 if (nsegs == 0) { /* First load segment */ 1410 obj->vaddrbase = trunc_page(ph->p_vaddr); 1411 obj->mapbase = obj->vaddrbase + obj->relocbase; 1412 } else { /* Last load segment */ 1413 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1414 obj->vaddrbase; 1415 } 1416 nsegs++; 1417 if ((ph->p_flags & PF_X) == PF_X) { 1418 obj->textsize = MAX(obj->textsize, 1419 round_page(ph->p_vaddr + ph->p_memsz) - obj->vaddrbase); 1420 } 1421 break; 1422 1423 case PT_DYNAMIC: 1424 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1425 break; 1426 1427 case PT_TLS: 1428 obj->tlsindex = 1; 1429 obj->tlssize = ph->p_memsz; 1430 obj->tlsalign = ph->p_align; 1431 obj->tlsinitsize = ph->p_filesz; 1432 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1433 break; 1434 1435 case PT_GNU_STACK: 1436 obj->stack_flags = ph->p_flags; 1437 break; 1438 1439 case PT_GNU_RELRO: 1440 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1441 obj->relro_size = round_page(ph->p_memsz); 1442 break; 1443 1444 case PT_NOTE: 1445 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1446 note_end = note_start + ph->p_filesz; 1447 digest_notes(obj, note_start, note_end); 1448 break; 1449 } 1450 } 1451 if (nsegs < 1) { 1452 _rtld_error("%s: too few PT_LOAD segments", path); 1453 return NULL; 1454 } 1455 1456 obj->entry = entry; 1457 return obj; 1458 } 1459 1460 void 1461 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1462 { 1463 const Elf_Note *note; 1464 const char *note_name; 1465 uintptr_t p; 1466 1467 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1468 note = (const Elf_Note *)((const char *)(note + 1) + 1469 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1470 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1471 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1472 note->n_descsz != sizeof(int32_t)) 1473 continue; 1474 if (note->n_type != NT_FREEBSD_ABI_TAG && 1475 note->n_type != NT_FREEBSD_NOINIT_TAG) 1476 continue; 1477 note_name = (const char *)(note + 1); 1478 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1479 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1480 continue; 1481 switch (note->n_type) { 1482 case NT_FREEBSD_ABI_TAG: 1483 /* FreeBSD osrel note */ 1484 p = (uintptr_t)(note + 1); 1485 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1486 obj->osrel = *(const int32_t *)(p); 1487 dbg("note osrel %d", obj->osrel); 1488 break; 1489 case NT_FREEBSD_NOINIT_TAG: 1490 /* FreeBSD 'crt does not call init' note */ 1491 obj->crt_no_init = true; 1492 dbg("note crt_no_init"); 1493 break; 1494 } 1495 } 1496 } 1497 1498 static Obj_Entry * 1499 dlcheck(void *handle) 1500 { 1501 Obj_Entry *obj; 1502 1503 TAILQ_FOREACH(obj, &obj_list, next) { 1504 if (obj == (Obj_Entry *) handle) 1505 break; 1506 } 1507 1508 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1509 _rtld_error("Invalid shared object handle %p", handle); 1510 return NULL; 1511 } 1512 return obj; 1513 } 1514 1515 /* 1516 * If the given object is already in the donelist, return true. Otherwise 1517 * add the object to the list and return false. 1518 */ 1519 static bool 1520 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1521 { 1522 unsigned int i; 1523 1524 for (i = 0; i < dlp->num_used; i++) 1525 if (dlp->objs[i] == obj) 1526 return true; 1527 /* 1528 * Our donelist allocation should always be sufficient. But if 1529 * our threads locking isn't working properly, more shared objects 1530 * could have been loaded since we allocated the list. That should 1531 * never happen, but we'll handle it properly just in case it does. 1532 */ 1533 if (dlp->num_used < dlp->num_alloc) 1534 dlp->objs[dlp->num_used++] = obj; 1535 return false; 1536 } 1537 1538 /* 1539 * Hash function for symbol table lookup. Don't even think about changing 1540 * this. It is specified by the System V ABI. 1541 */ 1542 unsigned long 1543 elf_hash(const char *name) 1544 { 1545 const unsigned char *p = (const unsigned char *) name; 1546 unsigned long h = 0; 1547 unsigned long g; 1548 1549 while (*p != '\0') { 1550 h = (h << 4) + *p++; 1551 if ((g = h & 0xf0000000) != 0) 1552 h ^= g >> 24; 1553 h &= ~g; 1554 } 1555 return h; 1556 } 1557 1558 /* 1559 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1560 * unsigned in case it's implemented with a wider type. 1561 */ 1562 static uint32_t 1563 gnu_hash(const char *s) 1564 { 1565 uint32_t h; 1566 unsigned char c; 1567 1568 h = 5381; 1569 for (c = *s; c != '\0'; c = *++s) 1570 h = h * 33 + c; 1571 return (h & 0xffffffff); 1572 } 1573 1574 1575 /* 1576 * Find the library with the given name, and return its full pathname. 1577 * The returned string is dynamically allocated. Generates an error 1578 * message and returns NULL if the library cannot be found. 1579 * 1580 * If the second argument is non-NULL, then it refers to an already- 1581 * loaded shared object, whose library search path will be searched. 1582 * 1583 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1584 * descriptor (which is close-on-exec) will be passed out via the third 1585 * argument. 1586 * 1587 * The search order is: 1588 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1589 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1590 * LD_LIBRARY_PATH 1591 * DT_RUNPATH in the referencing file 1592 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1593 * from list) 1594 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1595 * 1596 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1597 */ 1598 static char * 1599 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1600 { 1601 char *pathname, *refobj_path; 1602 const char *name; 1603 bool nodeflib, objgiven; 1604 1605 objgiven = refobj != NULL; 1606 1607 if (libmap_disable || !objgiven || 1608 (name = lm_find(refobj->path, xname)) == NULL) 1609 name = xname; 1610 1611 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1612 if (name[0] != '/' && !trust) { 1613 _rtld_error("Absolute pathname required " 1614 "for shared object \"%s\"", name); 1615 return (NULL); 1616 } 1617 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1618 __DECONST(char *, name))); 1619 } 1620 1621 dbg(" Searching for \"%s\"", name); 1622 refobj_path = objgiven ? refobj->path : NULL; 1623 1624 /* 1625 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1626 * back to pre-conforming behaviour if user requested so with 1627 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1628 * nodeflib. 1629 */ 1630 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1631 pathname = search_library_path(name, ld_library_path, 1632 refobj_path, fdp); 1633 if (pathname != NULL) 1634 return (pathname); 1635 if (refobj != NULL) { 1636 pathname = search_library_path(name, refobj->rpath, 1637 refobj_path, fdp); 1638 if (pathname != NULL) 1639 return (pathname); 1640 } 1641 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1642 if (pathname != NULL) 1643 return (pathname); 1644 pathname = search_library_path(name, gethints(false), 1645 refobj_path, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 pathname = search_library_path(name, ld_standard_library_path, 1649 refobj_path, fdp); 1650 if (pathname != NULL) 1651 return (pathname); 1652 } else { 1653 nodeflib = objgiven ? refobj->z_nodeflib : false; 1654 if (objgiven) { 1655 pathname = search_library_path(name, refobj->rpath, 1656 refobj->path, fdp); 1657 if (pathname != NULL) 1658 return (pathname); 1659 } 1660 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1661 pathname = search_library_path(name, obj_main->rpath, 1662 refobj_path, fdp); 1663 if (pathname != NULL) 1664 return (pathname); 1665 } 1666 pathname = search_library_path(name, ld_library_path, 1667 refobj_path, fdp); 1668 if (pathname != NULL) 1669 return (pathname); 1670 if (objgiven) { 1671 pathname = search_library_path(name, refobj->runpath, 1672 refobj_path, fdp); 1673 if (pathname != NULL) 1674 return (pathname); 1675 } 1676 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1677 if (pathname != NULL) 1678 return (pathname); 1679 pathname = search_library_path(name, gethints(nodeflib), 1680 refobj_path, fdp); 1681 if (pathname != NULL) 1682 return (pathname); 1683 if (objgiven && !nodeflib) { 1684 pathname = search_library_path(name, 1685 ld_standard_library_path, refobj_path, fdp); 1686 if (pathname != NULL) 1687 return (pathname); 1688 } 1689 } 1690 1691 if (objgiven && refobj->path != NULL) { 1692 _rtld_error("Shared object \"%s\" not found, " 1693 "required by \"%s\"", name, basename(refobj->path)); 1694 } else { 1695 _rtld_error("Shared object \"%s\" not found", name); 1696 } 1697 return (NULL); 1698 } 1699 1700 /* 1701 * Given a symbol number in a referencing object, find the corresponding 1702 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1703 * no definition was found. Returns a pointer to the Obj_Entry of the 1704 * defining object via the reference parameter DEFOBJ_OUT. 1705 */ 1706 const Elf_Sym * 1707 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1708 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1709 RtldLockState *lockstate) 1710 { 1711 const Elf_Sym *ref; 1712 const Elf_Sym *def; 1713 const Obj_Entry *defobj; 1714 const Ver_Entry *ve; 1715 SymLook req; 1716 const char *name; 1717 int res; 1718 1719 /* 1720 * If we have already found this symbol, get the information from 1721 * the cache. 1722 */ 1723 if (symnum >= refobj->dynsymcount) 1724 return NULL; /* Bad object */ 1725 if (cache != NULL && cache[symnum].sym != NULL) { 1726 *defobj_out = cache[symnum].obj; 1727 return cache[symnum].sym; 1728 } 1729 1730 ref = refobj->symtab + symnum; 1731 name = refobj->strtab + ref->st_name; 1732 def = NULL; 1733 defobj = NULL; 1734 ve = NULL; 1735 1736 /* 1737 * We don't have to do a full scale lookup if the symbol is local. 1738 * We know it will bind to the instance in this load module; to 1739 * which we already have a pointer (ie ref). By not doing a lookup, 1740 * we not only improve performance, but it also avoids unresolvable 1741 * symbols when local symbols are not in the hash table. This has 1742 * been seen with the ia64 toolchain. 1743 */ 1744 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1745 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1746 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1747 symnum); 1748 } 1749 symlook_init(&req, name); 1750 req.flags = flags; 1751 ve = req.ventry = fetch_ventry(refobj, symnum); 1752 req.lockstate = lockstate; 1753 res = symlook_default(&req, refobj); 1754 if (res == 0) { 1755 def = req.sym_out; 1756 defobj = req.defobj_out; 1757 } 1758 } else { 1759 def = ref; 1760 defobj = refobj; 1761 } 1762 1763 /* 1764 * If we found no definition and the reference is weak, treat the 1765 * symbol as having the value zero. 1766 */ 1767 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1768 def = &sym_zero; 1769 defobj = obj_main; 1770 } 1771 1772 if (def != NULL) { 1773 *defobj_out = defobj; 1774 /* Record the information in the cache to avoid subsequent lookups. */ 1775 if (cache != NULL) { 1776 cache[symnum].sym = def; 1777 cache[symnum].obj = defobj; 1778 } 1779 } else { 1780 if (refobj != &obj_rtld) 1781 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1782 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1783 } 1784 return def; 1785 } 1786 1787 /* 1788 * Return the search path from the ldconfig hints file, reading it if 1789 * necessary. If nostdlib is true, then the default search paths are 1790 * not added to result. 1791 * 1792 * Returns NULL if there are problems with the hints file, 1793 * or if the search path there is empty. 1794 */ 1795 static const char * 1796 gethints(bool nostdlib) 1797 { 1798 static char *filtered_path; 1799 static const char *hints; 1800 static struct elfhints_hdr hdr; 1801 struct fill_search_info_args sargs, hargs; 1802 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1803 struct dl_serpath *SLPpath, *hintpath; 1804 char *p; 1805 struct stat hint_stat; 1806 unsigned int SLPndx, hintndx, fndx, fcount; 1807 int fd; 1808 size_t flen; 1809 uint32_t dl; 1810 bool skip; 1811 1812 /* First call, read the hints file */ 1813 if (hints == NULL) { 1814 /* Keep from trying again in case the hints file is bad. */ 1815 hints = ""; 1816 1817 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1818 return (NULL); 1819 1820 /* 1821 * Check of hdr.dirlistlen value against type limit 1822 * intends to pacify static analyzers. Further 1823 * paranoia leads to checks that dirlist is fully 1824 * contained in the file range. 1825 */ 1826 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1827 hdr.magic != ELFHINTS_MAGIC || 1828 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1829 fstat(fd, &hint_stat) == -1) { 1830 cleanup1: 1831 close(fd); 1832 hdr.dirlistlen = 0; 1833 return (NULL); 1834 } 1835 dl = hdr.strtab; 1836 if (dl + hdr.dirlist < dl) 1837 goto cleanup1; 1838 dl += hdr.dirlist; 1839 if (dl + hdr.dirlistlen < dl) 1840 goto cleanup1; 1841 dl += hdr.dirlistlen; 1842 if (dl > hint_stat.st_size) 1843 goto cleanup1; 1844 p = xmalloc(hdr.dirlistlen + 1); 1845 if (pread(fd, p, hdr.dirlistlen + 1, 1846 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1847 p[hdr.dirlistlen] != '\0') { 1848 free(p); 1849 goto cleanup1; 1850 } 1851 hints = p; 1852 close(fd); 1853 } 1854 1855 /* 1856 * If caller agreed to receive list which includes the default 1857 * paths, we are done. Otherwise, if we still did not 1858 * calculated filtered result, do it now. 1859 */ 1860 if (!nostdlib) 1861 return (hints[0] != '\0' ? hints : NULL); 1862 if (filtered_path != NULL) 1863 goto filt_ret; 1864 1865 /* 1866 * Obtain the list of all configured search paths, and the 1867 * list of the default paths. 1868 * 1869 * First estimate the size of the results. 1870 */ 1871 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1872 smeta.dls_cnt = 0; 1873 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1874 hmeta.dls_cnt = 0; 1875 1876 sargs.request = RTLD_DI_SERINFOSIZE; 1877 sargs.serinfo = &smeta; 1878 hargs.request = RTLD_DI_SERINFOSIZE; 1879 hargs.serinfo = &hmeta; 1880 1881 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1882 &sargs); 1883 path_enumerate(hints, fill_search_info, NULL, &hargs); 1884 1885 SLPinfo = xmalloc(smeta.dls_size); 1886 hintinfo = xmalloc(hmeta.dls_size); 1887 1888 /* 1889 * Next fetch both sets of paths. 1890 */ 1891 sargs.request = RTLD_DI_SERINFO; 1892 sargs.serinfo = SLPinfo; 1893 sargs.serpath = &SLPinfo->dls_serpath[0]; 1894 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1895 1896 hargs.request = RTLD_DI_SERINFO; 1897 hargs.serinfo = hintinfo; 1898 hargs.serpath = &hintinfo->dls_serpath[0]; 1899 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1900 1901 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1902 &sargs); 1903 path_enumerate(hints, fill_search_info, NULL, &hargs); 1904 1905 /* 1906 * Now calculate the difference between two sets, by excluding 1907 * standard paths from the full set. 1908 */ 1909 fndx = 0; 1910 fcount = 0; 1911 filtered_path = xmalloc(hdr.dirlistlen + 1); 1912 hintpath = &hintinfo->dls_serpath[0]; 1913 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1914 skip = false; 1915 SLPpath = &SLPinfo->dls_serpath[0]; 1916 /* 1917 * Check each standard path against current. 1918 */ 1919 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1920 /* matched, skip the path */ 1921 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1922 skip = true; 1923 break; 1924 } 1925 } 1926 if (skip) 1927 continue; 1928 /* 1929 * Not matched against any standard path, add the path 1930 * to result. Separate consequtive paths with ':'. 1931 */ 1932 if (fcount > 0) { 1933 filtered_path[fndx] = ':'; 1934 fndx++; 1935 } 1936 fcount++; 1937 flen = strlen(hintpath->dls_name); 1938 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1939 fndx += flen; 1940 } 1941 filtered_path[fndx] = '\0'; 1942 1943 free(SLPinfo); 1944 free(hintinfo); 1945 1946 filt_ret: 1947 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1948 } 1949 1950 static void 1951 init_dag(Obj_Entry *root) 1952 { 1953 const Needed_Entry *needed; 1954 const Objlist_Entry *elm; 1955 DoneList donelist; 1956 1957 if (root->dag_inited) 1958 return; 1959 donelist_init(&donelist); 1960 1961 /* Root object belongs to own DAG. */ 1962 objlist_push_tail(&root->dldags, root); 1963 objlist_push_tail(&root->dagmembers, root); 1964 donelist_check(&donelist, root); 1965 1966 /* 1967 * Add dependencies of root object to DAG in breadth order 1968 * by exploiting the fact that each new object get added 1969 * to the tail of the dagmembers list. 1970 */ 1971 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1972 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1973 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1974 continue; 1975 objlist_push_tail(&needed->obj->dldags, root); 1976 objlist_push_tail(&root->dagmembers, needed->obj); 1977 } 1978 } 1979 root->dag_inited = true; 1980 } 1981 1982 static void 1983 init_marker(Obj_Entry *marker) 1984 { 1985 1986 bzero(marker, sizeof(*marker)); 1987 marker->marker = true; 1988 } 1989 1990 Obj_Entry * 1991 globallist_curr(const Obj_Entry *obj) 1992 { 1993 1994 for (;;) { 1995 if (obj == NULL) 1996 return (NULL); 1997 if (!obj->marker) 1998 return (__DECONST(Obj_Entry *, obj)); 1999 obj = TAILQ_PREV(obj, obj_entry_q, next); 2000 } 2001 } 2002 2003 Obj_Entry * 2004 globallist_next(const Obj_Entry *obj) 2005 { 2006 2007 for (;;) { 2008 obj = TAILQ_NEXT(obj, next); 2009 if (obj == NULL) 2010 return (NULL); 2011 if (!obj->marker) 2012 return (__DECONST(Obj_Entry *, obj)); 2013 } 2014 } 2015 2016 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2017 static void 2018 hold_object(Obj_Entry *obj) 2019 { 2020 2021 obj->holdcount++; 2022 } 2023 2024 static void 2025 unhold_object(Obj_Entry *obj) 2026 { 2027 2028 assert(obj->holdcount > 0); 2029 if (--obj->holdcount == 0 && obj->unholdfree) 2030 release_object(obj); 2031 } 2032 2033 static void 2034 process_z(Obj_Entry *root) 2035 { 2036 const Objlist_Entry *elm; 2037 Obj_Entry *obj; 2038 2039 /* 2040 * Walk over object DAG and process every dependent object 2041 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2042 * to grow their own DAG. 2043 * 2044 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2045 * symlook_global() to work. 2046 * 2047 * For DF_1_NODELETE, the DAG should have its reference upped. 2048 */ 2049 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2050 obj = elm->obj; 2051 if (obj == NULL) 2052 continue; 2053 if (obj->z_nodelete && !obj->ref_nodel) { 2054 dbg("obj %s -z nodelete", obj->path); 2055 init_dag(obj); 2056 ref_dag(obj); 2057 obj->ref_nodel = true; 2058 } 2059 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2060 dbg("obj %s -z global", obj->path); 2061 objlist_push_tail(&list_global, obj); 2062 init_dag(obj); 2063 } 2064 } 2065 } 2066 /* 2067 * Initialize the dynamic linker. The argument is the address at which 2068 * the dynamic linker has been mapped into memory. The primary task of 2069 * this function is to relocate the dynamic linker. 2070 */ 2071 static void 2072 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2073 { 2074 Obj_Entry objtmp; /* Temporary rtld object */ 2075 const Elf_Ehdr *ehdr; 2076 const Elf_Dyn *dyn_rpath; 2077 const Elf_Dyn *dyn_soname; 2078 const Elf_Dyn *dyn_runpath; 2079 2080 #ifdef RTLD_INIT_PAGESIZES_EARLY 2081 /* The page size is required by the dynamic memory allocator. */ 2082 init_pagesizes(aux_info); 2083 #endif 2084 2085 /* 2086 * Conjure up an Obj_Entry structure for the dynamic linker. 2087 * 2088 * The "path" member can't be initialized yet because string constants 2089 * cannot yet be accessed. Below we will set it correctly. 2090 */ 2091 memset(&objtmp, 0, sizeof(objtmp)); 2092 objtmp.path = NULL; 2093 objtmp.rtld = true; 2094 objtmp.mapbase = mapbase; 2095 #ifdef PIC 2096 objtmp.relocbase = mapbase; 2097 #endif 2098 2099 objtmp.dynamic = rtld_dynamic(&objtmp); 2100 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2101 assert(objtmp.needed == NULL); 2102 #if !defined(__mips__) 2103 /* MIPS has a bogus DT_TEXTREL. */ 2104 assert(!objtmp.textrel); 2105 #endif 2106 /* 2107 * Temporarily put the dynamic linker entry into the object list, so 2108 * that symbols can be found. 2109 */ 2110 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2111 2112 ehdr = (Elf_Ehdr *)mapbase; 2113 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2114 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2115 2116 /* Initialize the object list. */ 2117 TAILQ_INIT(&obj_list); 2118 2119 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2120 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2121 2122 #ifndef RTLD_INIT_PAGESIZES_EARLY 2123 /* The page size is required by the dynamic memory allocator. */ 2124 init_pagesizes(aux_info); 2125 #endif 2126 2127 if (aux_info[AT_OSRELDATE] != NULL) 2128 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2129 2130 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2131 2132 /* Replace the path with a dynamically allocated copy. */ 2133 obj_rtld.path = xstrdup(ld_path_rtld); 2134 2135 r_debug.r_brk = r_debug_state; 2136 r_debug.r_state = RT_CONSISTENT; 2137 } 2138 2139 /* 2140 * Retrieve the array of supported page sizes. The kernel provides the page 2141 * sizes in increasing order. 2142 */ 2143 static void 2144 init_pagesizes(Elf_Auxinfo **aux_info) 2145 { 2146 static size_t psa[MAXPAGESIZES]; 2147 int mib[2]; 2148 size_t len, size; 2149 2150 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2151 NULL) { 2152 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2153 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2154 } else { 2155 len = 2; 2156 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2157 size = sizeof(psa); 2158 else { 2159 /* As a fallback, retrieve the base page size. */ 2160 size = sizeof(psa[0]); 2161 if (aux_info[AT_PAGESZ] != NULL) { 2162 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2163 goto psa_filled; 2164 } else { 2165 mib[0] = CTL_HW; 2166 mib[1] = HW_PAGESIZE; 2167 len = 2; 2168 } 2169 } 2170 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2171 _rtld_error("sysctl for hw.pagesize(s) failed"); 2172 rtld_die(); 2173 } 2174 psa_filled: 2175 pagesizes = psa; 2176 } 2177 npagesizes = size / sizeof(pagesizes[0]); 2178 /* Discard any invalid entries at the end of the array. */ 2179 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2180 npagesizes--; 2181 } 2182 2183 /* 2184 * Add the init functions from a needed object list (and its recursive 2185 * needed objects) to "list". This is not used directly; it is a helper 2186 * function for initlist_add_objects(). The write lock must be held 2187 * when this function is called. 2188 */ 2189 static void 2190 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2191 { 2192 /* Recursively process the successor needed objects. */ 2193 if (needed->next != NULL) 2194 initlist_add_neededs(needed->next, list); 2195 2196 /* Process the current needed object. */ 2197 if (needed->obj != NULL) 2198 initlist_add_objects(needed->obj, needed->obj, list); 2199 } 2200 2201 /* 2202 * Scan all of the DAGs rooted in the range of objects from "obj" to 2203 * "tail" and add their init functions to "list". This recurses over 2204 * the DAGs and ensure the proper init ordering such that each object's 2205 * needed libraries are initialized before the object itself. At the 2206 * same time, this function adds the objects to the global finalization 2207 * list "list_fini" in the opposite order. The write lock must be 2208 * held when this function is called. 2209 */ 2210 static void 2211 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2212 { 2213 Obj_Entry *nobj; 2214 2215 if (obj->init_scanned || obj->init_done) 2216 return; 2217 obj->init_scanned = true; 2218 2219 /* Recursively process the successor objects. */ 2220 nobj = globallist_next(obj); 2221 if (nobj != NULL && obj != tail) 2222 initlist_add_objects(nobj, tail, list); 2223 2224 /* Recursively process the needed objects. */ 2225 if (obj->needed != NULL) 2226 initlist_add_neededs(obj->needed, list); 2227 if (obj->needed_filtees != NULL) 2228 initlist_add_neededs(obj->needed_filtees, list); 2229 if (obj->needed_aux_filtees != NULL) 2230 initlist_add_neededs(obj->needed_aux_filtees, list); 2231 2232 /* Add the object to the init list. */ 2233 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2234 obj->init_array != (Elf_Addr)NULL) 2235 objlist_push_tail(list, obj); 2236 2237 /* Add the object to the global fini list in the reverse order. */ 2238 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2239 && !obj->on_fini_list) { 2240 objlist_push_head(&list_fini, obj); 2241 obj->on_fini_list = true; 2242 } 2243 } 2244 2245 #ifndef FPTR_TARGET 2246 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2247 #endif 2248 2249 static void 2250 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2251 { 2252 Needed_Entry *needed, *needed1; 2253 2254 for (needed = n; needed != NULL; needed = needed->next) { 2255 if (needed->obj != NULL) { 2256 dlclose_locked(needed->obj, lockstate); 2257 needed->obj = NULL; 2258 } 2259 } 2260 for (needed = n; needed != NULL; needed = needed1) { 2261 needed1 = needed->next; 2262 free(needed); 2263 } 2264 } 2265 2266 static void 2267 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2268 { 2269 2270 free_needed_filtees(obj->needed_filtees, lockstate); 2271 obj->needed_filtees = NULL; 2272 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2273 obj->needed_aux_filtees = NULL; 2274 obj->filtees_loaded = false; 2275 } 2276 2277 static void 2278 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2279 RtldLockState *lockstate) 2280 { 2281 2282 for (; needed != NULL; needed = needed->next) { 2283 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2284 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2285 RTLD_LOCAL, lockstate); 2286 } 2287 } 2288 2289 static void 2290 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2291 { 2292 2293 lock_restart_for_upgrade(lockstate); 2294 if (!obj->filtees_loaded) { 2295 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2296 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2297 obj->filtees_loaded = true; 2298 } 2299 } 2300 2301 static int 2302 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2303 { 2304 Obj_Entry *obj1; 2305 2306 for (; needed != NULL; needed = needed->next) { 2307 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2308 flags & ~RTLD_LO_NOLOAD); 2309 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2310 return (-1); 2311 } 2312 return (0); 2313 } 2314 2315 /* 2316 * Given a shared object, traverse its list of needed objects, and load 2317 * each of them. Returns 0 on success. Generates an error message and 2318 * returns -1 on failure. 2319 */ 2320 static int 2321 load_needed_objects(Obj_Entry *first, int flags) 2322 { 2323 Obj_Entry *obj; 2324 2325 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2326 if (obj->marker) 2327 continue; 2328 if (process_needed(obj, obj->needed, flags) == -1) 2329 return (-1); 2330 } 2331 return (0); 2332 } 2333 2334 static int 2335 load_preload_objects(void) 2336 { 2337 char *p = ld_preload; 2338 Obj_Entry *obj; 2339 static const char delim[] = " \t:;"; 2340 2341 if (p == NULL) 2342 return 0; 2343 2344 p += strspn(p, delim); 2345 while (*p != '\0') { 2346 size_t len = strcspn(p, delim); 2347 char savech; 2348 2349 savech = p[len]; 2350 p[len] = '\0'; 2351 obj = load_object(p, -1, NULL, 0); 2352 if (obj == NULL) 2353 return -1; /* XXX - cleanup */ 2354 obj->z_interpose = true; 2355 p[len] = savech; 2356 p += len; 2357 p += strspn(p, delim); 2358 } 2359 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2360 return 0; 2361 } 2362 2363 static const char * 2364 printable_path(const char *path) 2365 { 2366 2367 return (path == NULL ? "<unknown>" : path); 2368 } 2369 2370 /* 2371 * Load a shared object into memory, if it is not already loaded. The 2372 * object may be specified by name or by user-supplied file descriptor 2373 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2374 * duplicate is. 2375 * 2376 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2377 * on failure. 2378 */ 2379 static Obj_Entry * 2380 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2381 { 2382 Obj_Entry *obj; 2383 int fd; 2384 struct stat sb; 2385 char *path; 2386 2387 fd = -1; 2388 if (name != NULL) { 2389 TAILQ_FOREACH(obj, &obj_list, next) { 2390 if (obj->marker || obj->doomed) 2391 continue; 2392 if (object_match_name(obj, name)) 2393 return (obj); 2394 } 2395 2396 path = find_library(name, refobj, &fd); 2397 if (path == NULL) 2398 return (NULL); 2399 } else 2400 path = NULL; 2401 2402 if (fd >= 0) { 2403 /* 2404 * search_library_pathfds() opens a fresh file descriptor for the 2405 * library, so there is no need to dup(). 2406 */ 2407 } else if (fd_u == -1) { 2408 /* 2409 * If we didn't find a match by pathname, or the name is not 2410 * supplied, open the file and check again by device and inode. 2411 * This avoids false mismatches caused by multiple links or ".." 2412 * in pathnames. 2413 * 2414 * To avoid a race, we open the file and use fstat() rather than 2415 * using stat(). 2416 */ 2417 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2418 _rtld_error("Cannot open \"%s\"", path); 2419 free(path); 2420 return (NULL); 2421 } 2422 } else { 2423 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2424 if (fd == -1) { 2425 _rtld_error("Cannot dup fd"); 2426 free(path); 2427 return (NULL); 2428 } 2429 } 2430 if (fstat(fd, &sb) == -1) { 2431 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2432 close(fd); 2433 free(path); 2434 return NULL; 2435 } 2436 TAILQ_FOREACH(obj, &obj_list, next) { 2437 if (obj->marker || obj->doomed) 2438 continue; 2439 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2440 break; 2441 } 2442 if (obj != NULL && name != NULL) { 2443 object_add_name(obj, name); 2444 free(path); 2445 close(fd); 2446 return obj; 2447 } 2448 if (flags & RTLD_LO_NOLOAD) { 2449 free(path); 2450 close(fd); 2451 return (NULL); 2452 } 2453 2454 /* First use of this object, so we must map it in */ 2455 obj = do_load_object(fd, name, path, &sb, flags); 2456 if (obj == NULL) 2457 free(path); 2458 close(fd); 2459 2460 return obj; 2461 } 2462 2463 static Obj_Entry * 2464 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2465 int flags) 2466 { 2467 Obj_Entry *obj; 2468 struct statfs fs; 2469 2470 /* 2471 * but first, make sure that environment variables haven't been 2472 * used to circumvent the noexec flag on a filesystem. 2473 */ 2474 if (dangerous_ld_env) { 2475 if (fstatfs(fd, &fs) != 0) { 2476 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2477 return NULL; 2478 } 2479 if (fs.f_flags & MNT_NOEXEC) { 2480 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2481 return NULL; 2482 } 2483 } 2484 dbg("loading \"%s\"", printable_path(path)); 2485 obj = map_object(fd, printable_path(path), sbp); 2486 if (obj == NULL) 2487 return NULL; 2488 2489 /* 2490 * If DT_SONAME is present in the object, digest_dynamic2 already 2491 * added it to the object names. 2492 */ 2493 if (name != NULL) 2494 object_add_name(obj, name); 2495 obj->path = path; 2496 digest_dynamic(obj, 0); 2497 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2498 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2499 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2500 RTLD_LO_DLOPEN) { 2501 dbg("refusing to load non-loadable \"%s\"", obj->path); 2502 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2503 munmap(obj->mapbase, obj->mapsize); 2504 obj_free(obj); 2505 return (NULL); 2506 } 2507 2508 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2509 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2510 obj_count++; 2511 obj_loads++; 2512 linkmap_add(obj); /* for GDB & dlinfo() */ 2513 max_stack_flags |= obj->stack_flags; 2514 2515 dbg(" %p .. %p: %s", obj->mapbase, 2516 obj->mapbase + obj->mapsize - 1, obj->path); 2517 if (obj->textrel) 2518 dbg(" WARNING: %s has impure text", obj->path); 2519 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2520 obj->path); 2521 2522 return obj; 2523 } 2524 2525 static Obj_Entry * 2526 obj_from_addr(const void *addr) 2527 { 2528 Obj_Entry *obj; 2529 2530 TAILQ_FOREACH(obj, &obj_list, next) { 2531 if (obj->marker) 2532 continue; 2533 if (addr < (void *) obj->mapbase) 2534 continue; 2535 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2536 return obj; 2537 } 2538 return NULL; 2539 } 2540 2541 static void 2542 preinit_main(void) 2543 { 2544 Elf_Addr *preinit_addr; 2545 int index; 2546 2547 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2548 if (preinit_addr == NULL) 2549 return; 2550 2551 for (index = 0; index < obj_main->preinit_array_num; index++) { 2552 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2553 dbg("calling preinit function for %s at %p", obj_main->path, 2554 (void *)preinit_addr[index]); 2555 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2556 0, 0, obj_main->path); 2557 call_init_pointer(obj_main, preinit_addr[index]); 2558 } 2559 } 2560 } 2561 2562 /* 2563 * Call the finalization functions for each of the objects in "list" 2564 * belonging to the DAG of "root" and referenced once. If NULL "root" 2565 * is specified, every finalization function will be called regardless 2566 * of the reference count and the list elements won't be freed. All of 2567 * the objects are expected to have non-NULL fini functions. 2568 */ 2569 static void 2570 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2571 { 2572 Objlist_Entry *elm; 2573 char *saved_msg; 2574 Elf_Addr *fini_addr; 2575 int index; 2576 2577 assert(root == NULL || root->refcount == 1); 2578 2579 if (root != NULL) 2580 root->doomed = true; 2581 2582 /* 2583 * Preserve the current error message since a fini function might 2584 * call into the dynamic linker and overwrite it. 2585 */ 2586 saved_msg = errmsg_save(); 2587 do { 2588 STAILQ_FOREACH(elm, list, link) { 2589 if (root != NULL && (elm->obj->refcount != 1 || 2590 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2591 continue; 2592 /* Remove object from fini list to prevent recursive invocation. */ 2593 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2594 /* Ensure that new references cannot be acquired. */ 2595 elm->obj->doomed = true; 2596 2597 hold_object(elm->obj); 2598 lock_release(rtld_bind_lock, lockstate); 2599 /* 2600 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2601 * When this happens, DT_FINI_ARRAY is processed first. 2602 */ 2603 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2604 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2605 for (index = elm->obj->fini_array_num - 1; index >= 0; 2606 index--) { 2607 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2608 dbg("calling fini function for %s at %p", 2609 elm->obj->path, (void *)fini_addr[index]); 2610 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2611 (void *)fini_addr[index], 0, 0, elm->obj->path); 2612 call_initfini_pointer(elm->obj, fini_addr[index]); 2613 } 2614 } 2615 } 2616 if (elm->obj->fini != (Elf_Addr)NULL) { 2617 dbg("calling fini function for %s at %p", elm->obj->path, 2618 (void *)elm->obj->fini); 2619 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2620 0, 0, elm->obj->path); 2621 call_initfini_pointer(elm->obj, elm->obj->fini); 2622 } 2623 wlock_acquire(rtld_bind_lock, lockstate); 2624 unhold_object(elm->obj); 2625 /* No need to free anything if process is going down. */ 2626 if (root != NULL) 2627 free(elm); 2628 /* 2629 * We must restart the list traversal after every fini call 2630 * because a dlclose() call from the fini function or from 2631 * another thread might have modified the reference counts. 2632 */ 2633 break; 2634 } 2635 } while (elm != NULL); 2636 errmsg_restore(saved_msg); 2637 } 2638 2639 /* 2640 * Call the initialization functions for each of the objects in 2641 * "list". All of the objects are expected to have non-NULL init 2642 * functions. 2643 */ 2644 static void 2645 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2646 { 2647 Objlist_Entry *elm; 2648 Obj_Entry *obj; 2649 char *saved_msg; 2650 Elf_Addr *init_addr; 2651 int index; 2652 2653 /* 2654 * Clean init_scanned flag so that objects can be rechecked and 2655 * possibly initialized earlier if any of vectors called below 2656 * cause the change by using dlopen. 2657 */ 2658 TAILQ_FOREACH(obj, &obj_list, next) { 2659 if (obj->marker) 2660 continue; 2661 obj->init_scanned = false; 2662 } 2663 2664 /* 2665 * Preserve the current error message since an init function might 2666 * call into the dynamic linker and overwrite it. 2667 */ 2668 saved_msg = errmsg_save(); 2669 STAILQ_FOREACH(elm, list, link) { 2670 if (elm->obj->init_done) /* Initialized early. */ 2671 continue; 2672 /* 2673 * Race: other thread might try to use this object before current 2674 * one completes the initialization. Not much can be done here 2675 * without better locking. 2676 */ 2677 elm->obj->init_done = true; 2678 hold_object(elm->obj); 2679 lock_release(rtld_bind_lock, lockstate); 2680 2681 /* 2682 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2683 * When this happens, DT_INIT is processed first. 2684 */ 2685 if (elm->obj->init != (Elf_Addr)NULL) { 2686 dbg("calling init function for %s at %p", elm->obj->path, 2687 (void *)elm->obj->init); 2688 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2689 0, 0, elm->obj->path); 2690 call_initfini_pointer(elm->obj, elm->obj->init); 2691 } 2692 init_addr = (Elf_Addr *)elm->obj->init_array; 2693 if (init_addr != NULL) { 2694 for (index = 0; index < elm->obj->init_array_num; index++) { 2695 if (init_addr[index] != 0 && init_addr[index] != 1) { 2696 dbg("calling init function for %s at %p", elm->obj->path, 2697 (void *)init_addr[index]); 2698 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2699 (void *)init_addr[index], 0, 0, elm->obj->path); 2700 call_init_pointer(elm->obj, init_addr[index]); 2701 } 2702 } 2703 } 2704 wlock_acquire(rtld_bind_lock, lockstate); 2705 unhold_object(elm->obj); 2706 } 2707 errmsg_restore(saved_msg); 2708 } 2709 2710 static void 2711 objlist_clear(Objlist *list) 2712 { 2713 Objlist_Entry *elm; 2714 2715 while (!STAILQ_EMPTY(list)) { 2716 elm = STAILQ_FIRST(list); 2717 STAILQ_REMOVE_HEAD(list, link); 2718 free(elm); 2719 } 2720 } 2721 2722 static Objlist_Entry * 2723 objlist_find(Objlist *list, const Obj_Entry *obj) 2724 { 2725 Objlist_Entry *elm; 2726 2727 STAILQ_FOREACH(elm, list, link) 2728 if (elm->obj == obj) 2729 return elm; 2730 return NULL; 2731 } 2732 2733 static void 2734 objlist_init(Objlist *list) 2735 { 2736 STAILQ_INIT(list); 2737 } 2738 2739 static void 2740 objlist_push_head(Objlist *list, Obj_Entry *obj) 2741 { 2742 Objlist_Entry *elm; 2743 2744 elm = NEW(Objlist_Entry); 2745 elm->obj = obj; 2746 STAILQ_INSERT_HEAD(list, elm, link); 2747 } 2748 2749 static void 2750 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2751 { 2752 Objlist_Entry *elm; 2753 2754 elm = NEW(Objlist_Entry); 2755 elm->obj = obj; 2756 STAILQ_INSERT_TAIL(list, elm, link); 2757 } 2758 2759 static void 2760 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2761 { 2762 Objlist_Entry *elm, *listelm; 2763 2764 STAILQ_FOREACH(listelm, list, link) { 2765 if (listelm->obj == listobj) 2766 break; 2767 } 2768 elm = NEW(Objlist_Entry); 2769 elm->obj = obj; 2770 if (listelm != NULL) 2771 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2772 else 2773 STAILQ_INSERT_TAIL(list, elm, link); 2774 } 2775 2776 static void 2777 objlist_remove(Objlist *list, Obj_Entry *obj) 2778 { 2779 Objlist_Entry *elm; 2780 2781 if ((elm = objlist_find(list, obj)) != NULL) { 2782 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2783 free(elm); 2784 } 2785 } 2786 2787 /* 2788 * Relocate dag rooted in the specified object. 2789 * Returns 0 on success, or -1 on failure. 2790 */ 2791 2792 static int 2793 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2794 int flags, RtldLockState *lockstate) 2795 { 2796 Objlist_Entry *elm; 2797 int error; 2798 2799 error = 0; 2800 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2801 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2802 lockstate); 2803 if (error == -1) 2804 break; 2805 } 2806 return (error); 2807 } 2808 2809 /* 2810 * Prepare for, or clean after, relocating an object marked with 2811 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2812 * segments are remapped read-write. After relocations are done, the 2813 * segment's permissions are returned back to the modes specified in 2814 * the phdrs. If any relocation happened, or always for wired 2815 * program, COW is triggered. 2816 */ 2817 static int 2818 reloc_textrel_prot(Obj_Entry *obj, bool before) 2819 { 2820 const Elf_Phdr *ph; 2821 void *base; 2822 size_t l, sz; 2823 int prot; 2824 2825 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2826 l--, ph++) { 2827 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2828 continue; 2829 base = obj->relocbase + trunc_page(ph->p_vaddr); 2830 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2831 trunc_page(ph->p_vaddr); 2832 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2833 if (mprotect(base, sz, prot) == -1) { 2834 _rtld_error("%s: Cannot write-%sable text segment: %s", 2835 obj->path, before ? "en" : "dis", 2836 rtld_strerror(errno)); 2837 return (-1); 2838 } 2839 } 2840 return (0); 2841 } 2842 2843 /* 2844 * Relocate single object. 2845 * Returns 0 on success, or -1 on failure. 2846 */ 2847 static int 2848 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2849 int flags, RtldLockState *lockstate) 2850 { 2851 2852 if (obj->relocated) 2853 return (0); 2854 obj->relocated = true; 2855 if (obj != rtldobj) 2856 dbg("relocating \"%s\"", obj->path); 2857 2858 if (obj->symtab == NULL || obj->strtab == NULL || 2859 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2860 _rtld_error("%s: Shared object has no run-time symbol table", 2861 obj->path); 2862 return (-1); 2863 } 2864 2865 /* There are relocations to the write-protected text segment. */ 2866 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2867 return (-1); 2868 2869 /* Process the non-PLT non-IFUNC relocations. */ 2870 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2871 return (-1); 2872 2873 /* Re-protected the text segment. */ 2874 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2875 return (-1); 2876 2877 /* Set the special PLT or GOT entries. */ 2878 init_pltgot(obj); 2879 2880 /* Process the PLT relocations. */ 2881 if (reloc_plt(obj) == -1) 2882 return (-1); 2883 /* Relocate the jump slots if we are doing immediate binding. */ 2884 if (obj->bind_now || bind_now) 2885 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2886 return (-1); 2887 2888 /* 2889 * Process the non-PLT IFUNC relocations. The relocations are 2890 * processed in two phases, because IFUNC resolvers may 2891 * reference other symbols, which must be readily processed 2892 * before resolvers are called. 2893 */ 2894 if (obj->non_plt_gnu_ifunc && 2895 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2896 return (-1); 2897 2898 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2899 return (-1); 2900 2901 /* 2902 * Set up the magic number and version in the Obj_Entry. These 2903 * were checked in the crt1.o from the original ElfKit, so we 2904 * set them for backward compatibility. 2905 */ 2906 obj->magic = RTLD_MAGIC; 2907 obj->version = RTLD_VERSION; 2908 2909 return (0); 2910 } 2911 2912 /* 2913 * Relocate newly-loaded shared objects. The argument is a pointer to 2914 * the Obj_Entry for the first such object. All objects from the first 2915 * to the end of the list of objects are relocated. Returns 0 on success, 2916 * or -1 on failure. 2917 */ 2918 static int 2919 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2920 int flags, RtldLockState *lockstate) 2921 { 2922 Obj_Entry *obj; 2923 int error; 2924 2925 for (error = 0, obj = first; obj != NULL; 2926 obj = TAILQ_NEXT(obj, next)) { 2927 if (obj->marker) 2928 continue; 2929 error = relocate_object(obj, bind_now, rtldobj, flags, 2930 lockstate); 2931 if (error == -1) 2932 break; 2933 } 2934 return (error); 2935 } 2936 2937 /* 2938 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2939 * referencing STT_GNU_IFUNC symbols is postponed till the other 2940 * relocations are done. The indirect functions specified as 2941 * ifunc are allowed to call other symbols, so we need to have 2942 * objects relocated before asking for resolution from indirects. 2943 * 2944 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2945 * instead of the usual lazy handling of PLT slots. It is 2946 * consistent with how GNU does it. 2947 */ 2948 static int 2949 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2950 RtldLockState *lockstate) 2951 { 2952 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2953 return (-1); 2954 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2955 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2956 return (-1); 2957 return (0); 2958 } 2959 2960 static int 2961 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2962 RtldLockState *lockstate) 2963 { 2964 Obj_Entry *obj; 2965 2966 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2967 if (obj->marker) 2968 continue; 2969 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2970 return (-1); 2971 } 2972 return (0); 2973 } 2974 2975 static int 2976 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2977 RtldLockState *lockstate) 2978 { 2979 Objlist_Entry *elm; 2980 2981 STAILQ_FOREACH(elm, list, link) { 2982 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2983 lockstate) == -1) 2984 return (-1); 2985 } 2986 return (0); 2987 } 2988 2989 /* 2990 * Cleanup procedure. It will be called (by the atexit mechanism) just 2991 * before the process exits. 2992 */ 2993 static void 2994 rtld_exit(void) 2995 { 2996 RtldLockState lockstate; 2997 2998 wlock_acquire(rtld_bind_lock, &lockstate); 2999 dbg("rtld_exit()"); 3000 objlist_call_fini(&list_fini, NULL, &lockstate); 3001 /* No need to remove the items from the list, since we are exiting. */ 3002 if (!libmap_disable) 3003 lm_fini(); 3004 lock_release(rtld_bind_lock, &lockstate); 3005 } 3006 3007 /* 3008 * Iterate over a search path, translate each element, and invoke the 3009 * callback on the result. 3010 */ 3011 static void * 3012 path_enumerate(const char *path, path_enum_proc callback, 3013 const char *refobj_path, void *arg) 3014 { 3015 const char *trans; 3016 if (path == NULL) 3017 return (NULL); 3018 3019 path += strspn(path, ":;"); 3020 while (*path != '\0') { 3021 size_t len; 3022 char *res; 3023 3024 len = strcspn(path, ":;"); 3025 trans = lm_findn(refobj_path, path, len); 3026 if (trans) 3027 res = callback(trans, strlen(trans), arg); 3028 else 3029 res = callback(path, len, arg); 3030 3031 if (res != NULL) 3032 return (res); 3033 3034 path += len; 3035 path += strspn(path, ":;"); 3036 } 3037 3038 return (NULL); 3039 } 3040 3041 struct try_library_args { 3042 const char *name; 3043 size_t namelen; 3044 char *buffer; 3045 size_t buflen; 3046 int fd; 3047 }; 3048 3049 static void * 3050 try_library_path(const char *dir, size_t dirlen, void *param) 3051 { 3052 struct try_library_args *arg; 3053 int fd; 3054 3055 arg = param; 3056 if (*dir == '/' || trust) { 3057 char *pathname; 3058 3059 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3060 return (NULL); 3061 3062 pathname = arg->buffer; 3063 strncpy(pathname, dir, dirlen); 3064 pathname[dirlen] = '/'; 3065 strcpy(pathname + dirlen + 1, arg->name); 3066 3067 dbg(" Trying \"%s\"", pathname); 3068 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3069 if (fd >= 0) { 3070 dbg(" Opened \"%s\", fd %d", pathname, fd); 3071 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3072 strcpy(pathname, arg->buffer); 3073 arg->fd = fd; 3074 return (pathname); 3075 } else { 3076 dbg(" Failed to open \"%s\": %s", 3077 pathname, rtld_strerror(errno)); 3078 } 3079 } 3080 return (NULL); 3081 } 3082 3083 static char * 3084 search_library_path(const char *name, const char *path, 3085 const char *refobj_path, int *fdp) 3086 { 3087 char *p; 3088 struct try_library_args arg; 3089 3090 if (path == NULL) 3091 return NULL; 3092 3093 arg.name = name; 3094 arg.namelen = strlen(name); 3095 arg.buffer = xmalloc(PATH_MAX); 3096 arg.buflen = PATH_MAX; 3097 arg.fd = -1; 3098 3099 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3100 *fdp = arg.fd; 3101 3102 free(arg.buffer); 3103 3104 return (p); 3105 } 3106 3107 3108 /* 3109 * Finds the library with the given name using the directory descriptors 3110 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3111 * 3112 * Returns a freshly-opened close-on-exec file descriptor for the library, 3113 * or -1 if the library cannot be found. 3114 */ 3115 static char * 3116 search_library_pathfds(const char *name, const char *path, int *fdp) 3117 { 3118 char *envcopy, *fdstr, *found, *last_token; 3119 size_t len; 3120 int dirfd, fd; 3121 3122 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3123 3124 /* Don't load from user-specified libdirs into setuid binaries. */ 3125 if (!trust) 3126 return (NULL); 3127 3128 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3129 if (path == NULL) 3130 return (NULL); 3131 3132 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3133 if (name[0] == '/') { 3134 dbg("Absolute path (%s) passed to %s", name, __func__); 3135 return (NULL); 3136 } 3137 3138 /* 3139 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3140 * copy of the path, as strtok_r rewrites separator tokens 3141 * with '\0'. 3142 */ 3143 found = NULL; 3144 envcopy = xstrdup(path); 3145 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3146 fdstr = strtok_r(NULL, ":", &last_token)) { 3147 dirfd = parse_integer(fdstr); 3148 if (dirfd < 0) { 3149 _rtld_error("failed to parse directory FD: '%s'", 3150 fdstr); 3151 break; 3152 } 3153 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3154 if (fd >= 0) { 3155 *fdp = fd; 3156 len = strlen(fdstr) + strlen(name) + 3; 3157 found = xmalloc(len); 3158 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3159 _rtld_error("error generating '%d/%s'", 3160 dirfd, name); 3161 rtld_die(); 3162 } 3163 dbg("open('%s') => %d", found, fd); 3164 break; 3165 } 3166 } 3167 free(envcopy); 3168 3169 return (found); 3170 } 3171 3172 3173 int 3174 dlclose(void *handle) 3175 { 3176 RtldLockState lockstate; 3177 int error; 3178 3179 wlock_acquire(rtld_bind_lock, &lockstate); 3180 error = dlclose_locked(handle, &lockstate); 3181 lock_release(rtld_bind_lock, &lockstate); 3182 return (error); 3183 } 3184 3185 static int 3186 dlclose_locked(void *handle, RtldLockState *lockstate) 3187 { 3188 Obj_Entry *root; 3189 3190 root = dlcheck(handle); 3191 if (root == NULL) 3192 return -1; 3193 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3194 root->path); 3195 3196 /* Unreference the object and its dependencies. */ 3197 root->dl_refcount--; 3198 3199 if (root->refcount == 1) { 3200 /* 3201 * The object will be no longer referenced, so we must unload it. 3202 * First, call the fini functions. 3203 */ 3204 objlist_call_fini(&list_fini, root, lockstate); 3205 3206 unref_dag(root); 3207 3208 /* Finish cleaning up the newly-unreferenced objects. */ 3209 GDB_STATE(RT_DELETE,&root->linkmap); 3210 unload_object(root, lockstate); 3211 GDB_STATE(RT_CONSISTENT,NULL); 3212 } else 3213 unref_dag(root); 3214 3215 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3216 return 0; 3217 } 3218 3219 char * 3220 dlerror(void) 3221 { 3222 char *msg = error_message; 3223 error_message = NULL; 3224 return msg; 3225 } 3226 3227 /* 3228 * This function is deprecated and has no effect. 3229 */ 3230 void 3231 dllockinit(void *context, 3232 void *(*_lock_create)(void *context) __unused, 3233 void (*_rlock_acquire)(void *lock) __unused, 3234 void (*_wlock_acquire)(void *lock) __unused, 3235 void (*_lock_release)(void *lock) __unused, 3236 void (*_lock_destroy)(void *lock) __unused, 3237 void (*context_destroy)(void *context)) 3238 { 3239 static void *cur_context; 3240 static void (*cur_context_destroy)(void *); 3241 3242 /* Just destroy the context from the previous call, if necessary. */ 3243 if (cur_context_destroy != NULL) 3244 cur_context_destroy(cur_context); 3245 cur_context = context; 3246 cur_context_destroy = context_destroy; 3247 } 3248 3249 void * 3250 dlopen(const char *name, int mode) 3251 { 3252 3253 return (rtld_dlopen(name, -1, mode)); 3254 } 3255 3256 void * 3257 fdlopen(int fd, int mode) 3258 { 3259 3260 return (rtld_dlopen(NULL, fd, mode)); 3261 } 3262 3263 static void * 3264 rtld_dlopen(const char *name, int fd, int mode) 3265 { 3266 RtldLockState lockstate; 3267 int lo_flags; 3268 3269 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3270 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3271 if (ld_tracing != NULL) { 3272 rlock_acquire(rtld_bind_lock, &lockstate); 3273 if (sigsetjmp(lockstate.env, 0) != 0) 3274 lock_upgrade(rtld_bind_lock, &lockstate); 3275 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3276 lock_release(rtld_bind_lock, &lockstate); 3277 } 3278 lo_flags = RTLD_LO_DLOPEN; 3279 if (mode & RTLD_NODELETE) 3280 lo_flags |= RTLD_LO_NODELETE; 3281 if (mode & RTLD_NOLOAD) 3282 lo_flags |= RTLD_LO_NOLOAD; 3283 if (ld_tracing != NULL) 3284 lo_flags |= RTLD_LO_TRACE; 3285 3286 return (dlopen_object(name, fd, obj_main, lo_flags, 3287 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3288 } 3289 3290 static void 3291 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3292 { 3293 3294 obj->dl_refcount--; 3295 unref_dag(obj); 3296 if (obj->refcount == 0) 3297 unload_object(obj, lockstate); 3298 } 3299 3300 static Obj_Entry * 3301 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3302 int mode, RtldLockState *lockstate) 3303 { 3304 Obj_Entry *old_obj_tail; 3305 Obj_Entry *obj; 3306 Objlist initlist; 3307 RtldLockState mlockstate; 3308 int result; 3309 3310 objlist_init(&initlist); 3311 3312 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3313 wlock_acquire(rtld_bind_lock, &mlockstate); 3314 lockstate = &mlockstate; 3315 } 3316 GDB_STATE(RT_ADD,NULL); 3317 3318 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3319 obj = NULL; 3320 if (name == NULL && fd == -1) { 3321 obj = obj_main; 3322 obj->refcount++; 3323 } else { 3324 obj = load_object(name, fd, refobj, lo_flags); 3325 } 3326 3327 if (obj) { 3328 obj->dl_refcount++; 3329 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3330 objlist_push_tail(&list_global, obj); 3331 if (globallist_next(old_obj_tail) != NULL) { 3332 /* We loaded something new. */ 3333 assert(globallist_next(old_obj_tail) == obj); 3334 result = load_needed_objects(obj, 3335 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3336 init_dag(obj); 3337 ref_dag(obj); 3338 if (result != -1) 3339 result = rtld_verify_versions(&obj->dagmembers); 3340 if (result != -1 && ld_tracing) 3341 goto trace; 3342 if (result == -1 || relocate_object_dag(obj, 3343 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3344 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3345 lockstate) == -1) { 3346 dlopen_cleanup(obj, lockstate); 3347 obj = NULL; 3348 } else if (lo_flags & RTLD_LO_EARLY) { 3349 /* 3350 * Do not call the init functions for early loaded 3351 * filtees. The image is still not initialized enough 3352 * for them to work. 3353 * 3354 * Our object is found by the global object list and 3355 * will be ordered among all init calls done right 3356 * before transferring control to main. 3357 */ 3358 } else { 3359 /* Make list of init functions to call. */ 3360 initlist_add_objects(obj, obj, &initlist); 3361 } 3362 /* 3363 * Process all no_delete or global objects here, given 3364 * them own DAGs to prevent their dependencies from being 3365 * unloaded. This has to be done after we have loaded all 3366 * of the dependencies, so that we do not miss any. 3367 */ 3368 if (obj != NULL) 3369 process_z(obj); 3370 } else { 3371 /* 3372 * Bump the reference counts for objects on this DAG. If 3373 * this is the first dlopen() call for the object that was 3374 * already loaded as a dependency, initialize the dag 3375 * starting at it. 3376 */ 3377 init_dag(obj); 3378 ref_dag(obj); 3379 3380 if ((lo_flags & RTLD_LO_TRACE) != 0) 3381 goto trace; 3382 } 3383 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3384 obj->z_nodelete) && !obj->ref_nodel) { 3385 dbg("obj %s nodelete", obj->path); 3386 ref_dag(obj); 3387 obj->z_nodelete = obj->ref_nodel = true; 3388 } 3389 } 3390 3391 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3392 name); 3393 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3394 3395 if (!(lo_flags & RTLD_LO_EARLY)) { 3396 map_stacks_exec(lockstate); 3397 } 3398 3399 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3400 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3401 lockstate) == -1) { 3402 objlist_clear(&initlist); 3403 dlopen_cleanup(obj, lockstate); 3404 if (lockstate == &mlockstate) 3405 lock_release(rtld_bind_lock, lockstate); 3406 return (NULL); 3407 } 3408 3409 if (!(lo_flags & RTLD_LO_EARLY)) { 3410 /* Call the init functions. */ 3411 objlist_call_init(&initlist, lockstate); 3412 } 3413 objlist_clear(&initlist); 3414 if (lockstate == &mlockstate) 3415 lock_release(rtld_bind_lock, lockstate); 3416 return obj; 3417 trace: 3418 trace_loaded_objects(obj); 3419 if (lockstate == &mlockstate) 3420 lock_release(rtld_bind_lock, lockstate); 3421 exit(0); 3422 } 3423 3424 static void * 3425 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3426 int flags) 3427 { 3428 DoneList donelist; 3429 const Obj_Entry *obj, *defobj; 3430 const Elf_Sym *def; 3431 SymLook req; 3432 RtldLockState lockstate; 3433 tls_index ti; 3434 void *sym; 3435 int res; 3436 3437 def = NULL; 3438 defobj = NULL; 3439 symlook_init(&req, name); 3440 req.ventry = ve; 3441 req.flags = flags | SYMLOOK_IN_PLT; 3442 req.lockstate = &lockstate; 3443 3444 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3445 rlock_acquire(rtld_bind_lock, &lockstate); 3446 if (sigsetjmp(lockstate.env, 0) != 0) 3447 lock_upgrade(rtld_bind_lock, &lockstate); 3448 if (handle == NULL || handle == RTLD_NEXT || 3449 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3450 3451 if ((obj = obj_from_addr(retaddr)) == NULL) { 3452 _rtld_error("Cannot determine caller's shared object"); 3453 lock_release(rtld_bind_lock, &lockstate); 3454 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3455 return NULL; 3456 } 3457 if (handle == NULL) { /* Just the caller's shared object. */ 3458 res = symlook_obj(&req, obj); 3459 if (res == 0) { 3460 def = req.sym_out; 3461 defobj = req.defobj_out; 3462 } 3463 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3464 handle == RTLD_SELF) { /* ... caller included */ 3465 if (handle == RTLD_NEXT) 3466 obj = globallist_next(obj); 3467 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3468 if (obj->marker) 3469 continue; 3470 res = symlook_obj(&req, obj); 3471 if (res == 0) { 3472 if (def == NULL || 3473 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3474 def = req.sym_out; 3475 defobj = req.defobj_out; 3476 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3477 break; 3478 } 3479 } 3480 } 3481 /* 3482 * Search the dynamic linker itself, and possibly resolve the 3483 * symbol from there. This is how the application links to 3484 * dynamic linker services such as dlopen. 3485 */ 3486 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3487 res = symlook_obj(&req, &obj_rtld); 3488 if (res == 0) { 3489 def = req.sym_out; 3490 defobj = req.defobj_out; 3491 } 3492 } 3493 } else { 3494 assert(handle == RTLD_DEFAULT); 3495 res = symlook_default(&req, obj); 3496 if (res == 0) { 3497 defobj = req.defobj_out; 3498 def = req.sym_out; 3499 } 3500 } 3501 } else { 3502 if ((obj = dlcheck(handle)) == NULL) { 3503 lock_release(rtld_bind_lock, &lockstate); 3504 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3505 return NULL; 3506 } 3507 3508 donelist_init(&donelist); 3509 if (obj->mainprog) { 3510 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3511 res = symlook_global(&req, &donelist); 3512 if (res == 0) { 3513 def = req.sym_out; 3514 defobj = req.defobj_out; 3515 } 3516 /* 3517 * Search the dynamic linker itself, and possibly resolve the 3518 * symbol from there. This is how the application links to 3519 * dynamic linker services such as dlopen. 3520 */ 3521 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3522 res = symlook_obj(&req, &obj_rtld); 3523 if (res == 0) { 3524 def = req.sym_out; 3525 defobj = req.defobj_out; 3526 } 3527 } 3528 } 3529 else { 3530 /* Search the whole DAG rooted at the given object. */ 3531 res = symlook_list(&req, &obj->dagmembers, &donelist); 3532 if (res == 0) { 3533 def = req.sym_out; 3534 defobj = req.defobj_out; 3535 } 3536 } 3537 } 3538 3539 if (def != NULL) { 3540 lock_release(rtld_bind_lock, &lockstate); 3541 3542 /* 3543 * The value required by the caller is derived from the value 3544 * of the symbol. this is simply the relocated value of the 3545 * symbol. 3546 */ 3547 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3548 sym = make_function_pointer(def, defobj); 3549 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3550 sym = rtld_resolve_ifunc(defobj, def); 3551 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3552 ti.ti_module = defobj->tlsindex; 3553 ti.ti_offset = def->st_value; 3554 sym = __tls_get_addr(&ti); 3555 } else 3556 sym = defobj->relocbase + def->st_value; 3557 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3558 return (sym); 3559 } 3560 3561 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3562 ve != NULL ? ve->name : ""); 3563 lock_release(rtld_bind_lock, &lockstate); 3564 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3565 return NULL; 3566 } 3567 3568 void * 3569 dlsym(void *handle, const char *name) 3570 { 3571 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3572 SYMLOOK_DLSYM); 3573 } 3574 3575 dlfunc_t 3576 dlfunc(void *handle, const char *name) 3577 { 3578 union { 3579 void *d; 3580 dlfunc_t f; 3581 } rv; 3582 3583 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3584 SYMLOOK_DLSYM); 3585 return (rv.f); 3586 } 3587 3588 void * 3589 dlvsym(void *handle, const char *name, const char *version) 3590 { 3591 Ver_Entry ventry; 3592 3593 ventry.name = version; 3594 ventry.file = NULL; 3595 ventry.hash = elf_hash(version); 3596 ventry.flags= 0; 3597 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3598 SYMLOOK_DLSYM); 3599 } 3600 3601 int 3602 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3603 { 3604 const Obj_Entry *obj; 3605 RtldLockState lockstate; 3606 3607 rlock_acquire(rtld_bind_lock, &lockstate); 3608 obj = obj_from_addr(addr); 3609 if (obj == NULL) { 3610 _rtld_error("No shared object contains address"); 3611 lock_release(rtld_bind_lock, &lockstate); 3612 return (0); 3613 } 3614 rtld_fill_dl_phdr_info(obj, phdr_info); 3615 lock_release(rtld_bind_lock, &lockstate); 3616 return (1); 3617 } 3618 3619 int 3620 dladdr(const void *addr, Dl_info *info) 3621 { 3622 const Obj_Entry *obj; 3623 const Elf_Sym *def; 3624 void *symbol_addr; 3625 unsigned long symoffset; 3626 RtldLockState lockstate; 3627 3628 rlock_acquire(rtld_bind_lock, &lockstate); 3629 obj = obj_from_addr(addr); 3630 if (obj == NULL) { 3631 _rtld_error("No shared object contains address"); 3632 lock_release(rtld_bind_lock, &lockstate); 3633 return 0; 3634 } 3635 info->dli_fname = obj->path; 3636 info->dli_fbase = obj->mapbase; 3637 info->dli_saddr = (void *)0; 3638 info->dli_sname = NULL; 3639 3640 /* 3641 * Walk the symbol list looking for the symbol whose address is 3642 * closest to the address sent in. 3643 */ 3644 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3645 def = obj->symtab + symoffset; 3646 3647 /* 3648 * For skip the symbol if st_shndx is either SHN_UNDEF or 3649 * SHN_COMMON. 3650 */ 3651 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3652 continue; 3653 3654 /* 3655 * If the symbol is greater than the specified address, or if it 3656 * is further away from addr than the current nearest symbol, 3657 * then reject it. 3658 */ 3659 symbol_addr = obj->relocbase + def->st_value; 3660 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3661 continue; 3662 3663 /* Update our idea of the nearest symbol. */ 3664 info->dli_sname = obj->strtab + def->st_name; 3665 info->dli_saddr = symbol_addr; 3666 3667 /* Exact match? */ 3668 if (info->dli_saddr == addr) 3669 break; 3670 } 3671 lock_release(rtld_bind_lock, &lockstate); 3672 return 1; 3673 } 3674 3675 int 3676 dlinfo(void *handle, int request, void *p) 3677 { 3678 const Obj_Entry *obj; 3679 RtldLockState lockstate; 3680 int error; 3681 3682 rlock_acquire(rtld_bind_lock, &lockstate); 3683 3684 if (handle == NULL || handle == RTLD_SELF) { 3685 void *retaddr; 3686 3687 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3688 if ((obj = obj_from_addr(retaddr)) == NULL) 3689 _rtld_error("Cannot determine caller's shared object"); 3690 } else 3691 obj = dlcheck(handle); 3692 3693 if (obj == NULL) { 3694 lock_release(rtld_bind_lock, &lockstate); 3695 return (-1); 3696 } 3697 3698 error = 0; 3699 switch (request) { 3700 case RTLD_DI_LINKMAP: 3701 *((struct link_map const **)p) = &obj->linkmap; 3702 break; 3703 case RTLD_DI_ORIGIN: 3704 error = rtld_dirname(obj->path, p); 3705 break; 3706 3707 case RTLD_DI_SERINFOSIZE: 3708 case RTLD_DI_SERINFO: 3709 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3710 break; 3711 3712 default: 3713 _rtld_error("Invalid request %d passed to dlinfo()", request); 3714 error = -1; 3715 } 3716 3717 lock_release(rtld_bind_lock, &lockstate); 3718 3719 return (error); 3720 } 3721 3722 static void 3723 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3724 { 3725 3726 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3727 phdr_info->dlpi_name = obj->path; 3728 phdr_info->dlpi_phdr = obj->phdr; 3729 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3730 phdr_info->dlpi_tls_modid = obj->tlsindex; 3731 phdr_info->dlpi_tls_data = obj->tlsinit; 3732 phdr_info->dlpi_adds = obj_loads; 3733 phdr_info->dlpi_subs = obj_loads - obj_count; 3734 } 3735 3736 int 3737 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3738 { 3739 struct dl_phdr_info phdr_info; 3740 Obj_Entry *obj, marker; 3741 RtldLockState bind_lockstate, phdr_lockstate; 3742 int error; 3743 3744 init_marker(&marker); 3745 error = 0; 3746 3747 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3748 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3749 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3750 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3751 rtld_fill_dl_phdr_info(obj, &phdr_info); 3752 hold_object(obj); 3753 lock_release(rtld_bind_lock, &bind_lockstate); 3754 3755 error = callback(&phdr_info, sizeof phdr_info, param); 3756 3757 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3758 unhold_object(obj); 3759 obj = globallist_next(&marker); 3760 TAILQ_REMOVE(&obj_list, &marker, next); 3761 if (error != 0) { 3762 lock_release(rtld_bind_lock, &bind_lockstate); 3763 lock_release(rtld_phdr_lock, &phdr_lockstate); 3764 return (error); 3765 } 3766 } 3767 3768 if (error == 0) { 3769 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3770 lock_release(rtld_bind_lock, &bind_lockstate); 3771 error = callback(&phdr_info, sizeof(phdr_info), param); 3772 } 3773 lock_release(rtld_phdr_lock, &phdr_lockstate); 3774 return (error); 3775 } 3776 3777 static void * 3778 fill_search_info(const char *dir, size_t dirlen, void *param) 3779 { 3780 struct fill_search_info_args *arg; 3781 3782 arg = param; 3783 3784 if (arg->request == RTLD_DI_SERINFOSIZE) { 3785 arg->serinfo->dls_cnt ++; 3786 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3787 } else { 3788 struct dl_serpath *s_entry; 3789 3790 s_entry = arg->serpath; 3791 s_entry->dls_name = arg->strspace; 3792 s_entry->dls_flags = arg->flags; 3793 3794 strncpy(arg->strspace, dir, dirlen); 3795 arg->strspace[dirlen] = '\0'; 3796 3797 arg->strspace += dirlen + 1; 3798 arg->serpath++; 3799 } 3800 3801 return (NULL); 3802 } 3803 3804 static int 3805 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3806 { 3807 struct dl_serinfo _info; 3808 struct fill_search_info_args args; 3809 3810 args.request = RTLD_DI_SERINFOSIZE; 3811 args.serinfo = &_info; 3812 3813 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3814 _info.dls_cnt = 0; 3815 3816 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3817 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3818 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3819 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3820 if (!obj->z_nodeflib) 3821 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3822 3823 3824 if (request == RTLD_DI_SERINFOSIZE) { 3825 info->dls_size = _info.dls_size; 3826 info->dls_cnt = _info.dls_cnt; 3827 return (0); 3828 } 3829 3830 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3831 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3832 return (-1); 3833 } 3834 3835 args.request = RTLD_DI_SERINFO; 3836 args.serinfo = info; 3837 args.serpath = &info->dls_serpath[0]; 3838 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3839 3840 args.flags = LA_SER_RUNPATH; 3841 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3842 return (-1); 3843 3844 args.flags = LA_SER_LIBPATH; 3845 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3846 return (-1); 3847 3848 args.flags = LA_SER_RUNPATH; 3849 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3850 return (-1); 3851 3852 args.flags = LA_SER_CONFIG; 3853 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3854 != NULL) 3855 return (-1); 3856 3857 args.flags = LA_SER_DEFAULT; 3858 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3859 fill_search_info, NULL, &args) != NULL) 3860 return (-1); 3861 return (0); 3862 } 3863 3864 static int 3865 rtld_dirname(const char *path, char *bname) 3866 { 3867 const char *endp; 3868 3869 /* Empty or NULL string gets treated as "." */ 3870 if (path == NULL || *path == '\0') { 3871 bname[0] = '.'; 3872 bname[1] = '\0'; 3873 return (0); 3874 } 3875 3876 /* Strip trailing slashes */ 3877 endp = path + strlen(path) - 1; 3878 while (endp > path && *endp == '/') 3879 endp--; 3880 3881 /* Find the start of the dir */ 3882 while (endp > path && *endp != '/') 3883 endp--; 3884 3885 /* Either the dir is "/" or there are no slashes */ 3886 if (endp == path) { 3887 bname[0] = *endp == '/' ? '/' : '.'; 3888 bname[1] = '\0'; 3889 return (0); 3890 } else { 3891 do { 3892 endp--; 3893 } while (endp > path && *endp == '/'); 3894 } 3895 3896 if (endp - path + 2 > PATH_MAX) 3897 { 3898 _rtld_error("Filename is too long: %s", path); 3899 return(-1); 3900 } 3901 3902 strncpy(bname, path, endp - path + 1); 3903 bname[endp - path + 1] = '\0'; 3904 return (0); 3905 } 3906 3907 static int 3908 rtld_dirname_abs(const char *path, char *base) 3909 { 3910 char *last; 3911 3912 if (realpath(path, base) == NULL) 3913 return (-1); 3914 dbg("%s -> %s", path, base); 3915 last = strrchr(base, '/'); 3916 if (last == NULL) 3917 return (-1); 3918 if (last != base) 3919 *last = '\0'; 3920 return (0); 3921 } 3922 3923 static void 3924 linkmap_add(Obj_Entry *obj) 3925 { 3926 struct link_map *l = &obj->linkmap; 3927 struct link_map *prev; 3928 3929 obj->linkmap.l_name = obj->path; 3930 obj->linkmap.l_addr = obj->mapbase; 3931 obj->linkmap.l_ld = obj->dynamic; 3932 #ifdef __mips__ 3933 /* GDB needs load offset on MIPS to use the symbols */ 3934 obj->linkmap.l_offs = obj->relocbase; 3935 #endif 3936 3937 if (r_debug.r_map == NULL) { 3938 r_debug.r_map = l; 3939 return; 3940 } 3941 3942 /* 3943 * Scan to the end of the list, but not past the entry for the 3944 * dynamic linker, which we want to keep at the very end. 3945 */ 3946 for (prev = r_debug.r_map; 3947 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3948 prev = prev->l_next) 3949 ; 3950 3951 /* Link in the new entry. */ 3952 l->l_prev = prev; 3953 l->l_next = prev->l_next; 3954 if (l->l_next != NULL) 3955 l->l_next->l_prev = l; 3956 prev->l_next = l; 3957 } 3958 3959 static void 3960 linkmap_delete(Obj_Entry *obj) 3961 { 3962 struct link_map *l = &obj->linkmap; 3963 3964 if (l->l_prev == NULL) { 3965 if ((r_debug.r_map = l->l_next) != NULL) 3966 l->l_next->l_prev = NULL; 3967 return; 3968 } 3969 3970 if ((l->l_prev->l_next = l->l_next) != NULL) 3971 l->l_next->l_prev = l->l_prev; 3972 } 3973 3974 /* 3975 * Function for the debugger to set a breakpoint on to gain control. 3976 * 3977 * The two parameters allow the debugger to easily find and determine 3978 * what the runtime loader is doing and to whom it is doing it. 3979 * 3980 * When the loadhook trap is hit (r_debug_state, set at program 3981 * initialization), the arguments can be found on the stack: 3982 * 3983 * +8 struct link_map *m 3984 * +4 struct r_debug *rd 3985 * +0 RetAddr 3986 */ 3987 void 3988 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3989 { 3990 /* 3991 * The following is a hack to force the compiler to emit calls to 3992 * this function, even when optimizing. If the function is empty, 3993 * the compiler is not obliged to emit any code for calls to it, 3994 * even when marked __noinline. However, gdb depends on those 3995 * calls being made. 3996 */ 3997 __compiler_membar(); 3998 } 3999 4000 /* 4001 * A function called after init routines have completed. This can be used to 4002 * break before a program's entry routine is called, and can be used when 4003 * main is not available in the symbol table. 4004 */ 4005 void 4006 _r_debug_postinit(struct link_map *m __unused) 4007 { 4008 4009 /* See r_debug_state(). */ 4010 __compiler_membar(); 4011 } 4012 4013 static void 4014 release_object(Obj_Entry *obj) 4015 { 4016 4017 if (obj->holdcount > 0) { 4018 obj->unholdfree = true; 4019 return; 4020 } 4021 munmap(obj->mapbase, obj->mapsize); 4022 linkmap_delete(obj); 4023 obj_free(obj); 4024 } 4025 4026 /* 4027 * Get address of the pointer variable in the main program. 4028 * Prefer non-weak symbol over the weak one. 4029 */ 4030 static const void ** 4031 get_program_var_addr(const char *name, RtldLockState *lockstate) 4032 { 4033 SymLook req; 4034 DoneList donelist; 4035 4036 symlook_init(&req, name); 4037 req.lockstate = lockstate; 4038 donelist_init(&donelist); 4039 if (symlook_global(&req, &donelist) != 0) 4040 return (NULL); 4041 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4042 return ((const void **)make_function_pointer(req.sym_out, 4043 req.defobj_out)); 4044 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4045 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4046 else 4047 return ((const void **)(req.defobj_out->relocbase + 4048 req.sym_out->st_value)); 4049 } 4050 4051 /* 4052 * Set a pointer variable in the main program to the given value. This 4053 * is used to set key variables such as "environ" before any of the 4054 * init functions are called. 4055 */ 4056 static void 4057 set_program_var(const char *name, const void *value) 4058 { 4059 const void **addr; 4060 4061 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4062 dbg("\"%s\": *%p <-- %p", name, addr, value); 4063 *addr = value; 4064 } 4065 } 4066 4067 /* 4068 * Search the global objects, including dependencies and main object, 4069 * for the given symbol. 4070 */ 4071 static int 4072 symlook_global(SymLook *req, DoneList *donelist) 4073 { 4074 SymLook req1; 4075 const Objlist_Entry *elm; 4076 int res; 4077 4078 symlook_init_from_req(&req1, req); 4079 4080 /* Search all objects loaded at program start up. */ 4081 if (req->defobj_out == NULL || 4082 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4083 res = symlook_list(&req1, &list_main, donelist); 4084 if (res == 0 && (req->defobj_out == NULL || 4085 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4086 req->sym_out = req1.sym_out; 4087 req->defobj_out = req1.defobj_out; 4088 assert(req->defobj_out != NULL); 4089 } 4090 } 4091 4092 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4093 STAILQ_FOREACH(elm, &list_global, link) { 4094 if (req->defobj_out != NULL && 4095 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4096 break; 4097 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4098 if (res == 0 && (req->defobj_out == NULL || 4099 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4100 req->sym_out = req1.sym_out; 4101 req->defobj_out = req1.defobj_out; 4102 assert(req->defobj_out != NULL); 4103 } 4104 } 4105 4106 return (req->sym_out != NULL ? 0 : ESRCH); 4107 } 4108 4109 /* 4110 * Given a symbol name in a referencing object, find the corresponding 4111 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4112 * no definition was found. Returns a pointer to the Obj_Entry of the 4113 * defining object via the reference parameter DEFOBJ_OUT. 4114 */ 4115 static int 4116 symlook_default(SymLook *req, const Obj_Entry *refobj) 4117 { 4118 DoneList donelist; 4119 const Objlist_Entry *elm; 4120 SymLook req1; 4121 int res; 4122 4123 donelist_init(&donelist); 4124 symlook_init_from_req(&req1, req); 4125 4126 /* 4127 * Look first in the referencing object if linked symbolically, 4128 * and similarly handle protected symbols. 4129 */ 4130 res = symlook_obj(&req1, refobj); 4131 if (res == 0 && (refobj->symbolic || 4132 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4133 req->sym_out = req1.sym_out; 4134 req->defobj_out = req1.defobj_out; 4135 assert(req->defobj_out != NULL); 4136 } 4137 if (refobj->symbolic || req->defobj_out != NULL) 4138 donelist_check(&donelist, refobj); 4139 4140 symlook_global(req, &donelist); 4141 4142 /* Search all dlopened DAGs containing the referencing object. */ 4143 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4144 if (req->sym_out != NULL && 4145 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4146 break; 4147 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4148 if (res == 0 && (req->sym_out == NULL || 4149 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4150 req->sym_out = req1.sym_out; 4151 req->defobj_out = req1.defobj_out; 4152 assert(req->defobj_out != NULL); 4153 } 4154 } 4155 4156 /* 4157 * Search the dynamic linker itself, and possibly resolve the 4158 * symbol from there. This is how the application links to 4159 * dynamic linker services such as dlopen. 4160 */ 4161 if (req->sym_out == NULL || 4162 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4163 res = symlook_obj(&req1, &obj_rtld); 4164 if (res == 0) { 4165 req->sym_out = req1.sym_out; 4166 req->defobj_out = req1.defobj_out; 4167 assert(req->defobj_out != NULL); 4168 } 4169 } 4170 4171 return (req->sym_out != NULL ? 0 : ESRCH); 4172 } 4173 4174 static int 4175 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4176 { 4177 const Elf_Sym *def; 4178 const Obj_Entry *defobj; 4179 const Objlist_Entry *elm; 4180 SymLook req1; 4181 int res; 4182 4183 def = NULL; 4184 defobj = NULL; 4185 STAILQ_FOREACH(elm, objlist, link) { 4186 if (donelist_check(dlp, elm->obj)) 4187 continue; 4188 symlook_init_from_req(&req1, req); 4189 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4190 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4191 def = req1.sym_out; 4192 defobj = req1.defobj_out; 4193 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4194 break; 4195 } 4196 } 4197 } 4198 if (def != NULL) { 4199 req->sym_out = def; 4200 req->defobj_out = defobj; 4201 return (0); 4202 } 4203 return (ESRCH); 4204 } 4205 4206 /* 4207 * Search the chain of DAGS cointed to by the given Needed_Entry 4208 * for a symbol of the given name. Each DAG is scanned completely 4209 * before advancing to the next one. Returns a pointer to the symbol, 4210 * or NULL if no definition was found. 4211 */ 4212 static int 4213 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4214 { 4215 const Elf_Sym *def; 4216 const Needed_Entry *n; 4217 const Obj_Entry *defobj; 4218 SymLook req1; 4219 int res; 4220 4221 def = NULL; 4222 defobj = NULL; 4223 symlook_init_from_req(&req1, req); 4224 for (n = needed; n != NULL; n = n->next) { 4225 if (n->obj == NULL || 4226 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4227 continue; 4228 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4229 def = req1.sym_out; 4230 defobj = req1.defobj_out; 4231 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4232 break; 4233 } 4234 } 4235 if (def != NULL) { 4236 req->sym_out = def; 4237 req->defobj_out = defobj; 4238 return (0); 4239 } 4240 return (ESRCH); 4241 } 4242 4243 /* 4244 * Search the symbol table of a single shared object for a symbol of 4245 * the given name and version, if requested. Returns a pointer to the 4246 * symbol, or NULL if no definition was found. If the object is 4247 * filter, return filtered symbol from filtee. 4248 * 4249 * The symbol's hash value is passed in for efficiency reasons; that 4250 * eliminates many recomputations of the hash value. 4251 */ 4252 int 4253 symlook_obj(SymLook *req, const Obj_Entry *obj) 4254 { 4255 DoneList donelist; 4256 SymLook req1; 4257 int flags, res, mres; 4258 4259 /* 4260 * If there is at least one valid hash at this point, we prefer to 4261 * use the faster GNU version if available. 4262 */ 4263 if (obj->valid_hash_gnu) 4264 mres = symlook_obj1_gnu(req, obj); 4265 else if (obj->valid_hash_sysv) 4266 mres = symlook_obj1_sysv(req, obj); 4267 else 4268 return (EINVAL); 4269 4270 if (mres == 0) { 4271 if (obj->needed_filtees != NULL) { 4272 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4273 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4274 donelist_init(&donelist); 4275 symlook_init_from_req(&req1, req); 4276 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4277 if (res == 0) { 4278 req->sym_out = req1.sym_out; 4279 req->defobj_out = req1.defobj_out; 4280 } 4281 return (res); 4282 } 4283 if (obj->needed_aux_filtees != NULL) { 4284 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4285 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4286 donelist_init(&donelist); 4287 symlook_init_from_req(&req1, req); 4288 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4289 if (res == 0) { 4290 req->sym_out = req1.sym_out; 4291 req->defobj_out = req1.defobj_out; 4292 return (res); 4293 } 4294 } 4295 } 4296 return (mres); 4297 } 4298 4299 /* Symbol match routine common to both hash functions */ 4300 static bool 4301 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4302 const unsigned long symnum) 4303 { 4304 Elf_Versym verndx; 4305 const Elf_Sym *symp; 4306 const char *strp; 4307 4308 symp = obj->symtab + symnum; 4309 strp = obj->strtab + symp->st_name; 4310 4311 switch (ELF_ST_TYPE(symp->st_info)) { 4312 case STT_FUNC: 4313 case STT_NOTYPE: 4314 case STT_OBJECT: 4315 case STT_COMMON: 4316 case STT_GNU_IFUNC: 4317 if (symp->st_value == 0) 4318 return (false); 4319 /* fallthrough */ 4320 case STT_TLS: 4321 if (symp->st_shndx != SHN_UNDEF) 4322 break; 4323 #ifndef __mips__ 4324 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4325 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4326 break; 4327 #endif 4328 /* fallthrough */ 4329 default: 4330 return (false); 4331 } 4332 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4333 return (false); 4334 4335 if (req->ventry == NULL) { 4336 if (obj->versyms != NULL) { 4337 verndx = VER_NDX(obj->versyms[symnum]); 4338 if (verndx > obj->vernum) { 4339 _rtld_error( 4340 "%s: symbol %s references wrong version %d", 4341 obj->path, obj->strtab + symnum, verndx); 4342 return (false); 4343 } 4344 /* 4345 * If we are not called from dlsym (i.e. this 4346 * is a normal relocation from unversioned 4347 * binary), accept the symbol immediately if 4348 * it happens to have first version after this 4349 * shared object became versioned. Otherwise, 4350 * if symbol is versioned and not hidden, 4351 * remember it. If it is the only symbol with 4352 * this name exported by the shared object, it 4353 * will be returned as a match by the calling 4354 * function. If symbol is global (verndx < 2) 4355 * accept it unconditionally. 4356 */ 4357 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4358 verndx == VER_NDX_GIVEN) { 4359 result->sym_out = symp; 4360 return (true); 4361 } 4362 else if (verndx >= VER_NDX_GIVEN) { 4363 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4364 == 0) { 4365 if (result->vsymp == NULL) 4366 result->vsymp = symp; 4367 result->vcount++; 4368 } 4369 return (false); 4370 } 4371 } 4372 result->sym_out = symp; 4373 return (true); 4374 } 4375 if (obj->versyms == NULL) { 4376 if (object_match_name(obj, req->ventry->name)) { 4377 _rtld_error("%s: object %s should provide version %s " 4378 "for symbol %s", obj_rtld.path, obj->path, 4379 req->ventry->name, obj->strtab + symnum); 4380 return (false); 4381 } 4382 } else { 4383 verndx = VER_NDX(obj->versyms[symnum]); 4384 if (verndx > obj->vernum) { 4385 _rtld_error("%s: symbol %s references wrong version %d", 4386 obj->path, obj->strtab + symnum, verndx); 4387 return (false); 4388 } 4389 if (obj->vertab[verndx].hash != req->ventry->hash || 4390 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4391 /* 4392 * Version does not match. Look if this is a 4393 * global symbol and if it is not hidden. If 4394 * global symbol (verndx < 2) is available, 4395 * use it. Do not return symbol if we are 4396 * called by dlvsym, because dlvsym looks for 4397 * a specific version and default one is not 4398 * what dlvsym wants. 4399 */ 4400 if ((req->flags & SYMLOOK_DLSYM) || 4401 (verndx >= VER_NDX_GIVEN) || 4402 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4403 return (false); 4404 } 4405 } 4406 result->sym_out = symp; 4407 return (true); 4408 } 4409 4410 /* 4411 * Search for symbol using SysV hash function. 4412 * obj->buckets is known not to be NULL at this point; the test for this was 4413 * performed with the obj->valid_hash_sysv assignment. 4414 */ 4415 static int 4416 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4417 { 4418 unsigned long symnum; 4419 Sym_Match_Result matchres; 4420 4421 matchres.sym_out = NULL; 4422 matchres.vsymp = NULL; 4423 matchres.vcount = 0; 4424 4425 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4426 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4427 if (symnum >= obj->nchains) 4428 return (ESRCH); /* Bad object */ 4429 4430 if (matched_symbol(req, obj, &matchres, symnum)) { 4431 req->sym_out = matchres.sym_out; 4432 req->defobj_out = obj; 4433 return (0); 4434 } 4435 } 4436 if (matchres.vcount == 1) { 4437 req->sym_out = matchres.vsymp; 4438 req->defobj_out = obj; 4439 return (0); 4440 } 4441 return (ESRCH); 4442 } 4443 4444 /* Search for symbol using GNU hash function */ 4445 static int 4446 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4447 { 4448 Elf_Addr bloom_word; 4449 const Elf32_Word *hashval; 4450 Elf32_Word bucket; 4451 Sym_Match_Result matchres; 4452 unsigned int h1, h2; 4453 unsigned long symnum; 4454 4455 matchres.sym_out = NULL; 4456 matchres.vsymp = NULL; 4457 matchres.vcount = 0; 4458 4459 /* Pick right bitmask word from Bloom filter array */ 4460 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4461 obj->maskwords_bm_gnu]; 4462 4463 /* Calculate modulus word size of gnu hash and its derivative */ 4464 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4465 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4466 4467 /* Filter out the "definitely not in set" queries */ 4468 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4469 return (ESRCH); 4470 4471 /* Locate hash chain and corresponding value element*/ 4472 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4473 if (bucket == 0) 4474 return (ESRCH); 4475 hashval = &obj->chain_zero_gnu[bucket]; 4476 do { 4477 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4478 symnum = hashval - obj->chain_zero_gnu; 4479 if (matched_symbol(req, obj, &matchres, symnum)) { 4480 req->sym_out = matchres.sym_out; 4481 req->defobj_out = obj; 4482 return (0); 4483 } 4484 } 4485 } while ((*hashval++ & 1) == 0); 4486 if (matchres.vcount == 1) { 4487 req->sym_out = matchres.vsymp; 4488 req->defobj_out = obj; 4489 return (0); 4490 } 4491 return (ESRCH); 4492 } 4493 4494 static void 4495 trace_loaded_objects(Obj_Entry *obj) 4496 { 4497 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4498 int c; 4499 4500 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4501 main_local = ""; 4502 4503 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4504 fmt1 = "\t%o => %p (%x)\n"; 4505 4506 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4507 fmt2 = "\t%o (%x)\n"; 4508 4509 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4510 4511 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4512 Needed_Entry *needed; 4513 const char *name, *path; 4514 bool is_lib; 4515 4516 if (obj->marker) 4517 continue; 4518 if (list_containers && obj->needed != NULL) 4519 rtld_printf("%s:\n", obj->path); 4520 for (needed = obj->needed; needed; needed = needed->next) { 4521 if (needed->obj != NULL) { 4522 if (needed->obj->traced && !list_containers) 4523 continue; 4524 needed->obj->traced = true; 4525 path = needed->obj->path; 4526 } else 4527 path = "not found"; 4528 4529 name = obj->strtab + needed->name; 4530 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4531 4532 fmt = is_lib ? fmt1 : fmt2; 4533 while ((c = *fmt++) != '\0') { 4534 switch (c) { 4535 default: 4536 rtld_putchar(c); 4537 continue; 4538 case '\\': 4539 switch (c = *fmt) { 4540 case '\0': 4541 continue; 4542 case 'n': 4543 rtld_putchar('\n'); 4544 break; 4545 case 't': 4546 rtld_putchar('\t'); 4547 break; 4548 } 4549 break; 4550 case '%': 4551 switch (c = *fmt) { 4552 case '\0': 4553 continue; 4554 case '%': 4555 default: 4556 rtld_putchar(c); 4557 break; 4558 case 'A': 4559 rtld_putstr(main_local); 4560 break; 4561 case 'a': 4562 rtld_putstr(obj_main->path); 4563 break; 4564 case 'o': 4565 rtld_putstr(name); 4566 break; 4567 #if 0 4568 case 'm': 4569 rtld_printf("%d", sodp->sod_major); 4570 break; 4571 case 'n': 4572 rtld_printf("%d", sodp->sod_minor); 4573 break; 4574 #endif 4575 case 'p': 4576 rtld_putstr(path); 4577 break; 4578 case 'x': 4579 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4580 0); 4581 break; 4582 } 4583 break; 4584 } 4585 ++fmt; 4586 } 4587 } 4588 } 4589 } 4590 4591 /* 4592 * Unload a dlopened object and its dependencies from memory and from 4593 * our data structures. It is assumed that the DAG rooted in the 4594 * object has already been unreferenced, and that the object has a 4595 * reference count of 0. 4596 */ 4597 static void 4598 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4599 { 4600 Obj_Entry marker, *obj, *next; 4601 4602 assert(root->refcount == 0); 4603 4604 /* 4605 * Pass over the DAG removing unreferenced objects from 4606 * appropriate lists. 4607 */ 4608 unlink_object(root); 4609 4610 /* Unmap all objects that are no longer referenced. */ 4611 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4612 next = TAILQ_NEXT(obj, next); 4613 if (obj->marker || obj->refcount != 0) 4614 continue; 4615 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4616 obj->mapsize, 0, obj->path); 4617 dbg("unloading \"%s\"", obj->path); 4618 /* 4619 * Unlink the object now to prevent new references from 4620 * being acquired while the bind lock is dropped in 4621 * recursive dlclose() invocations. 4622 */ 4623 TAILQ_REMOVE(&obj_list, obj, next); 4624 obj_count--; 4625 4626 if (obj->filtees_loaded) { 4627 if (next != NULL) { 4628 init_marker(&marker); 4629 TAILQ_INSERT_BEFORE(next, &marker, next); 4630 unload_filtees(obj, lockstate); 4631 next = TAILQ_NEXT(&marker, next); 4632 TAILQ_REMOVE(&obj_list, &marker, next); 4633 } else 4634 unload_filtees(obj, lockstate); 4635 } 4636 release_object(obj); 4637 } 4638 } 4639 4640 static void 4641 unlink_object(Obj_Entry *root) 4642 { 4643 Objlist_Entry *elm; 4644 4645 if (root->refcount == 0) { 4646 /* Remove the object from the RTLD_GLOBAL list. */ 4647 objlist_remove(&list_global, root); 4648 4649 /* Remove the object from all objects' DAG lists. */ 4650 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4651 objlist_remove(&elm->obj->dldags, root); 4652 if (elm->obj != root) 4653 unlink_object(elm->obj); 4654 } 4655 } 4656 } 4657 4658 static void 4659 ref_dag(Obj_Entry *root) 4660 { 4661 Objlist_Entry *elm; 4662 4663 assert(root->dag_inited); 4664 STAILQ_FOREACH(elm, &root->dagmembers, link) 4665 elm->obj->refcount++; 4666 } 4667 4668 static void 4669 unref_dag(Obj_Entry *root) 4670 { 4671 Objlist_Entry *elm; 4672 4673 assert(root->dag_inited); 4674 STAILQ_FOREACH(elm, &root->dagmembers, link) 4675 elm->obj->refcount--; 4676 } 4677 4678 /* 4679 * Common code for MD __tls_get_addr(). 4680 */ 4681 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4682 static void * 4683 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4684 { 4685 Elf_Addr *newdtv, *dtv; 4686 RtldLockState lockstate; 4687 int to_copy; 4688 4689 dtv = *dtvp; 4690 /* Check dtv generation in case new modules have arrived */ 4691 if (dtv[0] != tls_dtv_generation) { 4692 wlock_acquire(rtld_bind_lock, &lockstate); 4693 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4694 to_copy = dtv[1]; 4695 if (to_copy > tls_max_index) 4696 to_copy = tls_max_index; 4697 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4698 newdtv[0] = tls_dtv_generation; 4699 newdtv[1] = tls_max_index; 4700 free(dtv); 4701 lock_release(rtld_bind_lock, &lockstate); 4702 dtv = *dtvp = newdtv; 4703 } 4704 4705 /* Dynamically allocate module TLS if necessary */ 4706 if (dtv[index + 1] == 0) { 4707 /* Signal safe, wlock will block out signals. */ 4708 wlock_acquire(rtld_bind_lock, &lockstate); 4709 if (!dtv[index + 1]) 4710 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4711 lock_release(rtld_bind_lock, &lockstate); 4712 } 4713 return ((void *)(dtv[index + 1] + offset)); 4714 } 4715 4716 void * 4717 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4718 { 4719 Elf_Addr *dtv; 4720 4721 dtv = *dtvp; 4722 /* Check dtv generation in case new modules have arrived */ 4723 if (__predict_true(dtv[0] == tls_dtv_generation && 4724 dtv[index + 1] != 0)) 4725 return ((void *)(dtv[index + 1] + offset)); 4726 return (tls_get_addr_slow(dtvp, index, offset)); 4727 } 4728 4729 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4730 defined(__powerpc__) || defined(__riscv) 4731 4732 /* 4733 * Return pointer to allocated TLS block 4734 */ 4735 static void * 4736 get_tls_block_ptr(void *tcb, size_t tcbsize) 4737 { 4738 size_t extra_size, post_size, pre_size, tls_block_size; 4739 size_t tls_init_align; 4740 4741 tls_init_align = MAX(obj_main->tlsalign, 1); 4742 4743 /* Compute fragments sizes. */ 4744 extra_size = tcbsize - TLS_TCB_SIZE; 4745 post_size = calculate_tls_post_size(tls_init_align); 4746 tls_block_size = tcbsize + post_size; 4747 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4748 4749 return ((char *)tcb - pre_size - extra_size); 4750 } 4751 4752 /* 4753 * Allocate Static TLS using the Variant I method. 4754 * 4755 * For details on the layout, see lib/libc/gen/tls.c. 4756 * 4757 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4758 * it is based on tls_last_offset, and TLS offsets here are really TCB 4759 * offsets, whereas libc's tls_static_space is just the executable's static 4760 * TLS segment. 4761 */ 4762 void * 4763 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4764 { 4765 Obj_Entry *obj; 4766 char *tls_block; 4767 Elf_Addr *dtv, **tcb; 4768 Elf_Addr addr; 4769 Elf_Addr i; 4770 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4771 size_t tls_init_align; 4772 4773 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4774 return (oldtcb); 4775 4776 assert(tcbsize >= TLS_TCB_SIZE); 4777 maxalign = MAX(tcbalign, tls_static_max_align); 4778 tls_init_align = MAX(obj_main->tlsalign, 1); 4779 4780 /* Compute fragmets sizes. */ 4781 extra_size = tcbsize - TLS_TCB_SIZE; 4782 post_size = calculate_tls_post_size(tls_init_align); 4783 tls_block_size = tcbsize + post_size; 4784 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4785 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4786 4787 /* Allocate whole TLS block */ 4788 tls_block = malloc_aligned(tls_block_size, maxalign); 4789 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4790 4791 if (oldtcb != NULL) { 4792 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4793 tls_static_space); 4794 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4795 4796 /* Adjust the DTV. */ 4797 dtv = tcb[0]; 4798 for (i = 0; i < dtv[1]; i++) { 4799 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4800 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4801 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4802 } 4803 } 4804 } else { 4805 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4806 tcb[0] = dtv; 4807 dtv[0] = tls_dtv_generation; 4808 dtv[1] = tls_max_index; 4809 4810 for (obj = globallist_curr(objs); obj != NULL; 4811 obj = globallist_next(obj)) { 4812 if (obj->tlsoffset > 0) { 4813 addr = (Elf_Addr)tcb + obj->tlsoffset; 4814 if (obj->tlsinitsize > 0) 4815 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4816 if (obj->tlssize > obj->tlsinitsize) 4817 memset((void*)(addr + obj->tlsinitsize), 0, 4818 obj->tlssize - obj->tlsinitsize); 4819 dtv[obj->tlsindex + 1] = addr; 4820 } 4821 } 4822 } 4823 4824 return (tcb); 4825 } 4826 4827 void 4828 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4829 { 4830 Elf_Addr *dtv; 4831 Elf_Addr tlsstart, tlsend; 4832 size_t post_size; 4833 size_t dtvsize, i, tls_init_align; 4834 4835 assert(tcbsize >= TLS_TCB_SIZE); 4836 tls_init_align = MAX(obj_main->tlsalign, 1); 4837 4838 /* Compute fragments sizes. */ 4839 post_size = calculate_tls_post_size(tls_init_align); 4840 4841 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4842 tlsend = (Elf_Addr)tcb + tls_static_space; 4843 4844 dtv = *(Elf_Addr **)tcb; 4845 dtvsize = dtv[1]; 4846 for (i = 0; i < dtvsize; i++) { 4847 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4848 free((void*)dtv[i+2]); 4849 } 4850 } 4851 free(dtv); 4852 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4853 } 4854 4855 #endif 4856 4857 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4858 4859 /* 4860 * Allocate Static TLS using the Variant II method. 4861 */ 4862 void * 4863 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4864 { 4865 Obj_Entry *obj; 4866 size_t size, ralign; 4867 char *tls; 4868 Elf_Addr *dtv, *olddtv; 4869 Elf_Addr segbase, oldsegbase, addr; 4870 size_t i; 4871 4872 ralign = tcbalign; 4873 if (tls_static_max_align > ralign) 4874 ralign = tls_static_max_align; 4875 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4876 4877 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4878 tls = malloc_aligned(size, ralign); 4879 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4880 4881 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4882 ((Elf_Addr*)segbase)[0] = segbase; 4883 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4884 4885 dtv[0] = tls_dtv_generation; 4886 dtv[1] = tls_max_index; 4887 4888 if (oldtls) { 4889 /* 4890 * Copy the static TLS block over whole. 4891 */ 4892 oldsegbase = (Elf_Addr) oldtls; 4893 memcpy((void *)(segbase - tls_static_space), 4894 (const void *)(oldsegbase - tls_static_space), 4895 tls_static_space); 4896 4897 /* 4898 * If any dynamic TLS blocks have been created tls_get_addr(), 4899 * move them over. 4900 */ 4901 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4902 for (i = 0; i < olddtv[1]; i++) { 4903 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4904 dtv[i+2] = olddtv[i+2]; 4905 olddtv[i+2] = 0; 4906 } 4907 } 4908 4909 /* 4910 * We assume that this block was the one we created with 4911 * allocate_initial_tls(). 4912 */ 4913 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4914 } else { 4915 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4916 if (obj->marker || obj->tlsoffset == 0) 4917 continue; 4918 addr = segbase - obj->tlsoffset; 4919 memset((void*)(addr + obj->tlsinitsize), 4920 0, obj->tlssize - obj->tlsinitsize); 4921 if (obj->tlsinit) 4922 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4923 dtv[obj->tlsindex + 1] = addr; 4924 } 4925 } 4926 4927 return (void*) segbase; 4928 } 4929 4930 void 4931 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4932 { 4933 Elf_Addr* dtv; 4934 size_t size, ralign; 4935 int dtvsize, i; 4936 Elf_Addr tlsstart, tlsend; 4937 4938 /* 4939 * Figure out the size of the initial TLS block so that we can 4940 * find stuff which ___tls_get_addr() allocated dynamically. 4941 */ 4942 ralign = tcbalign; 4943 if (tls_static_max_align > ralign) 4944 ralign = tls_static_max_align; 4945 size = round(tls_static_space, ralign); 4946 4947 dtv = ((Elf_Addr**)tls)[1]; 4948 dtvsize = dtv[1]; 4949 tlsend = (Elf_Addr) tls; 4950 tlsstart = tlsend - size; 4951 for (i = 0; i < dtvsize; i++) { 4952 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4953 free_aligned((void *)dtv[i + 2]); 4954 } 4955 } 4956 4957 free_aligned((void *)tlsstart); 4958 free((void*) dtv); 4959 } 4960 4961 #endif 4962 4963 /* 4964 * Allocate TLS block for module with given index. 4965 */ 4966 void * 4967 allocate_module_tls(int index) 4968 { 4969 Obj_Entry* obj; 4970 char* p; 4971 4972 TAILQ_FOREACH(obj, &obj_list, next) { 4973 if (obj->marker) 4974 continue; 4975 if (obj->tlsindex == index) 4976 break; 4977 } 4978 if (!obj) { 4979 _rtld_error("Can't find module with TLS index %d", index); 4980 rtld_die(); 4981 } 4982 4983 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4984 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4985 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4986 4987 return p; 4988 } 4989 4990 bool 4991 allocate_tls_offset(Obj_Entry *obj) 4992 { 4993 size_t off; 4994 4995 if (obj->tls_done) 4996 return true; 4997 4998 if (obj->tlssize == 0) { 4999 obj->tls_done = true; 5000 return true; 5001 } 5002 5003 if (tls_last_offset == 0) 5004 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5005 else 5006 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5007 obj->tlssize, obj->tlsalign); 5008 5009 /* 5010 * If we have already fixed the size of the static TLS block, we 5011 * must stay within that size. When allocating the static TLS, we 5012 * leave a small amount of space spare to be used for dynamically 5013 * loading modules which use static TLS. 5014 */ 5015 if (tls_static_space != 0) { 5016 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5017 return false; 5018 } else if (obj->tlsalign > tls_static_max_align) { 5019 tls_static_max_align = obj->tlsalign; 5020 } 5021 5022 tls_last_offset = obj->tlsoffset = off; 5023 tls_last_size = obj->tlssize; 5024 obj->tls_done = true; 5025 5026 return true; 5027 } 5028 5029 void 5030 free_tls_offset(Obj_Entry *obj) 5031 { 5032 5033 /* 5034 * If we were the last thing to allocate out of the static TLS 5035 * block, we give our space back to the 'allocator'. This is a 5036 * simplistic workaround to allow libGL.so.1 to be loaded and 5037 * unloaded multiple times. 5038 */ 5039 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5040 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5041 tls_last_offset -= obj->tlssize; 5042 tls_last_size = 0; 5043 } 5044 } 5045 5046 void * 5047 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5048 { 5049 void *ret; 5050 RtldLockState lockstate; 5051 5052 wlock_acquire(rtld_bind_lock, &lockstate); 5053 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5054 tcbsize, tcbalign); 5055 lock_release(rtld_bind_lock, &lockstate); 5056 return (ret); 5057 } 5058 5059 void 5060 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5061 { 5062 RtldLockState lockstate; 5063 5064 wlock_acquire(rtld_bind_lock, &lockstate); 5065 free_tls(tcb, tcbsize, tcbalign); 5066 lock_release(rtld_bind_lock, &lockstate); 5067 } 5068 5069 static void 5070 object_add_name(Obj_Entry *obj, const char *name) 5071 { 5072 Name_Entry *entry; 5073 size_t len; 5074 5075 len = strlen(name); 5076 entry = malloc(sizeof(Name_Entry) + len); 5077 5078 if (entry != NULL) { 5079 strcpy(entry->name, name); 5080 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5081 } 5082 } 5083 5084 static int 5085 object_match_name(const Obj_Entry *obj, const char *name) 5086 { 5087 Name_Entry *entry; 5088 5089 STAILQ_FOREACH(entry, &obj->names, link) { 5090 if (strcmp(name, entry->name) == 0) 5091 return (1); 5092 } 5093 return (0); 5094 } 5095 5096 static Obj_Entry * 5097 locate_dependency(const Obj_Entry *obj, const char *name) 5098 { 5099 const Objlist_Entry *entry; 5100 const Needed_Entry *needed; 5101 5102 STAILQ_FOREACH(entry, &list_main, link) { 5103 if (object_match_name(entry->obj, name)) 5104 return entry->obj; 5105 } 5106 5107 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5108 if (strcmp(obj->strtab + needed->name, name) == 0 || 5109 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5110 /* 5111 * If there is DT_NEEDED for the name we are looking for, 5112 * we are all set. Note that object might not be found if 5113 * dependency was not loaded yet, so the function can 5114 * return NULL here. This is expected and handled 5115 * properly by the caller. 5116 */ 5117 return (needed->obj); 5118 } 5119 } 5120 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5121 obj->path, name); 5122 rtld_die(); 5123 } 5124 5125 static int 5126 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5127 const Elf_Vernaux *vna) 5128 { 5129 const Elf_Verdef *vd; 5130 const char *vername; 5131 5132 vername = refobj->strtab + vna->vna_name; 5133 vd = depobj->verdef; 5134 if (vd == NULL) { 5135 _rtld_error("%s: version %s required by %s not defined", 5136 depobj->path, vername, refobj->path); 5137 return (-1); 5138 } 5139 for (;;) { 5140 if (vd->vd_version != VER_DEF_CURRENT) { 5141 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5142 depobj->path, vd->vd_version); 5143 return (-1); 5144 } 5145 if (vna->vna_hash == vd->vd_hash) { 5146 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5147 ((const char *)vd + vd->vd_aux); 5148 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5149 return (0); 5150 } 5151 if (vd->vd_next == 0) 5152 break; 5153 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5154 } 5155 if (vna->vna_flags & VER_FLG_WEAK) 5156 return (0); 5157 _rtld_error("%s: version %s required by %s not found", 5158 depobj->path, vername, refobj->path); 5159 return (-1); 5160 } 5161 5162 static int 5163 rtld_verify_object_versions(Obj_Entry *obj) 5164 { 5165 const Elf_Verneed *vn; 5166 const Elf_Verdef *vd; 5167 const Elf_Verdaux *vda; 5168 const Elf_Vernaux *vna; 5169 const Obj_Entry *depobj; 5170 int maxvernum, vernum; 5171 5172 if (obj->ver_checked) 5173 return (0); 5174 obj->ver_checked = true; 5175 5176 maxvernum = 0; 5177 /* 5178 * Walk over defined and required version records and figure out 5179 * max index used by any of them. Do very basic sanity checking 5180 * while there. 5181 */ 5182 vn = obj->verneed; 5183 while (vn != NULL) { 5184 if (vn->vn_version != VER_NEED_CURRENT) { 5185 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5186 obj->path, vn->vn_version); 5187 return (-1); 5188 } 5189 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5190 for (;;) { 5191 vernum = VER_NEED_IDX(vna->vna_other); 5192 if (vernum > maxvernum) 5193 maxvernum = vernum; 5194 if (vna->vna_next == 0) 5195 break; 5196 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5197 } 5198 if (vn->vn_next == 0) 5199 break; 5200 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5201 } 5202 5203 vd = obj->verdef; 5204 while (vd != NULL) { 5205 if (vd->vd_version != VER_DEF_CURRENT) { 5206 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5207 obj->path, vd->vd_version); 5208 return (-1); 5209 } 5210 vernum = VER_DEF_IDX(vd->vd_ndx); 5211 if (vernum > maxvernum) 5212 maxvernum = vernum; 5213 if (vd->vd_next == 0) 5214 break; 5215 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5216 } 5217 5218 if (maxvernum == 0) 5219 return (0); 5220 5221 /* 5222 * Store version information in array indexable by version index. 5223 * Verify that object version requirements are satisfied along the 5224 * way. 5225 */ 5226 obj->vernum = maxvernum + 1; 5227 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5228 5229 vd = obj->verdef; 5230 while (vd != NULL) { 5231 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5232 vernum = VER_DEF_IDX(vd->vd_ndx); 5233 assert(vernum <= maxvernum); 5234 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5235 obj->vertab[vernum].hash = vd->vd_hash; 5236 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5237 obj->vertab[vernum].file = NULL; 5238 obj->vertab[vernum].flags = 0; 5239 } 5240 if (vd->vd_next == 0) 5241 break; 5242 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5243 } 5244 5245 vn = obj->verneed; 5246 while (vn != NULL) { 5247 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5248 if (depobj == NULL) 5249 return (-1); 5250 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5251 for (;;) { 5252 if (check_object_provided_version(obj, depobj, vna)) 5253 return (-1); 5254 vernum = VER_NEED_IDX(vna->vna_other); 5255 assert(vernum <= maxvernum); 5256 obj->vertab[vernum].hash = vna->vna_hash; 5257 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5258 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5259 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5260 VER_INFO_HIDDEN : 0; 5261 if (vna->vna_next == 0) 5262 break; 5263 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5264 } 5265 if (vn->vn_next == 0) 5266 break; 5267 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5268 } 5269 return 0; 5270 } 5271 5272 static int 5273 rtld_verify_versions(const Objlist *objlist) 5274 { 5275 Objlist_Entry *entry; 5276 int rc; 5277 5278 rc = 0; 5279 STAILQ_FOREACH(entry, objlist, link) { 5280 /* 5281 * Skip dummy objects or objects that have their version requirements 5282 * already checked. 5283 */ 5284 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5285 continue; 5286 if (rtld_verify_object_versions(entry->obj) == -1) { 5287 rc = -1; 5288 if (ld_tracing == NULL) 5289 break; 5290 } 5291 } 5292 if (rc == 0 || ld_tracing != NULL) 5293 rc = rtld_verify_object_versions(&obj_rtld); 5294 return rc; 5295 } 5296 5297 const Ver_Entry * 5298 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5299 { 5300 Elf_Versym vernum; 5301 5302 if (obj->vertab) { 5303 vernum = VER_NDX(obj->versyms[symnum]); 5304 if (vernum >= obj->vernum) { 5305 _rtld_error("%s: symbol %s has wrong verneed value %d", 5306 obj->path, obj->strtab + symnum, vernum); 5307 } else if (obj->vertab[vernum].hash != 0) { 5308 return &obj->vertab[vernum]; 5309 } 5310 } 5311 return NULL; 5312 } 5313 5314 int 5315 _rtld_get_stack_prot(void) 5316 { 5317 5318 return (stack_prot); 5319 } 5320 5321 int 5322 _rtld_is_dlopened(void *arg) 5323 { 5324 Obj_Entry *obj; 5325 RtldLockState lockstate; 5326 int res; 5327 5328 rlock_acquire(rtld_bind_lock, &lockstate); 5329 obj = dlcheck(arg); 5330 if (obj == NULL) 5331 obj = obj_from_addr(arg); 5332 if (obj == NULL) { 5333 _rtld_error("No shared object contains address"); 5334 lock_release(rtld_bind_lock, &lockstate); 5335 return (-1); 5336 } 5337 res = obj->dlopened ? 1 : 0; 5338 lock_release(rtld_bind_lock, &lockstate); 5339 return (res); 5340 } 5341 5342 int 5343 obj_enforce_relro(Obj_Entry *obj) 5344 { 5345 5346 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5347 PROT_READ) == -1) { 5348 _rtld_error("%s: Cannot enforce relro protection: %s", 5349 obj->path, rtld_strerror(errno)); 5350 return (-1); 5351 } 5352 return (0); 5353 } 5354 5355 static void 5356 map_stacks_exec(RtldLockState *lockstate) 5357 { 5358 void (*thr_map_stacks_exec)(void); 5359 5360 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5361 return; 5362 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5363 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5364 if (thr_map_stacks_exec != NULL) { 5365 stack_prot |= PROT_EXEC; 5366 thr_map_stacks_exec(); 5367 } 5368 } 5369 5370 void 5371 symlook_init(SymLook *dst, const char *name) 5372 { 5373 5374 bzero(dst, sizeof(*dst)); 5375 dst->name = name; 5376 dst->hash = elf_hash(name); 5377 dst->hash_gnu = gnu_hash(name); 5378 } 5379 5380 static void 5381 symlook_init_from_req(SymLook *dst, const SymLook *src) 5382 { 5383 5384 dst->name = src->name; 5385 dst->hash = src->hash; 5386 dst->hash_gnu = src->hash_gnu; 5387 dst->ventry = src->ventry; 5388 dst->flags = src->flags; 5389 dst->defobj_out = NULL; 5390 dst->sym_out = NULL; 5391 dst->lockstate = src->lockstate; 5392 } 5393 5394 static int 5395 open_binary_fd(const char *argv0, bool search_in_path) 5396 { 5397 char *pathenv, *pe, binpath[PATH_MAX]; 5398 int fd; 5399 5400 if (search_in_path && strchr(argv0, '/') == NULL) { 5401 pathenv = getenv("PATH"); 5402 if (pathenv == NULL) { 5403 _rtld_error("-p and no PATH environment variable"); 5404 rtld_die(); 5405 } 5406 pathenv = strdup(pathenv); 5407 if (pathenv == NULL) { 5408 _rtld_error("Cannot allocate memory"); 5409 rtld_die(); 5410 } 5411 fd = -1; 5412 errno = ENOENT; 5413 while ((pe = strsep(&pathenv, ":")) != NULL) { 5414 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5415 sizeof(binpath)) 5416 continue; 5417 if (binpath[0] != '\0' && 5418 strlcat(binpath, "/", sizeof(binpath)) >= 5419 sizeof(binpath)) 5420 continue; 5421 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5422 sizeof(binpath)) 5423 continue; 5424 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5425 if (fd != -1 || errno != ENOENT) 5426 break; 5427 } 5428 free(pathenv); 5429 } else { 5430 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5431 } 5432 5433 if (fd == -1) { 5434 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5435 rtld_die(); 5436 } 5437 return (fd); 5438 } 5439 5440 /* 5441 * Parse a set of command-line arguments. 5442 */ 5443 static int 5444 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5445 { 5446 const char *arg; 5447 int fd, i, j, arglen; 5448 char opt; 5449 5450 dbg("Parsing command-line arguments"); 5451 *use_pathp = false; 5452 *fdp = -1; 5453 5454 for (i = 1; i < argc; i++ ) { 5455 arg = argv[i]; 5456 dbg("argv[%d]: '%s'", i, arg); 5457 5458 /* 5459 * rtld arguments end with an explicit "--" or with the first 5460 * non-prefixed argument. 5461 */ 5462 if (strcmp(arg, "--") == 0) { 5463 i++; 5464 break; 5465 } 5466 if (arg[0] != '-') 5467 break; 5468 5469 /* 5470 * All other arguments are single-character options that can 5471 * be combined, so we need to search through `arg` for them. 5472 */ 5473 arglen = strlen(arg); 5474 for (j = 1; j < arglen; j++) { 5475 opt = arg[j]; 5476 if (opt == 'h') { 5477 print_usage(argv[0]); 5478 _exit(0); 5479 } else if (opt == 'f') { 5480 /* 5481 * -f XX can be used to specify a descriptor for the 5482 * binary named at the command line (i.e., the later 5483 * argument will specify the process name but the 5484 * descriptor is what will actually be executed) 5485 */ 5486 if (j != arglen - 1) { 5487 /* -f must be the last option in, e.g., -abcf */ 5488 _rtld_error("Invalid options: %s", arg); 5489 rtld_die(); 5490 } 5491 i++; 5492 fd = parse_integer(argv[i]); 5493 if (fd == -1) { 5494 _rtld_error("Invalid file descriptor: '%s'", 5495 argv[i]); 5496 rtld_die(); 5497 } 5498 *fdp = fd; 5499 break; 5500 } else if (opt == 'p') { 5501 *use_pathp = true; 5502 } else { 5503 _rtld_error("Invalid argument: '%s'", arg); 5504 print_usage(argv[0]); 5505 rtld_die(); 5506 } 5507 } 5508 } 5509 5510 return (i); 5511 } 5512 5513 /* 5514 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5515 */ 5516 static int 5517 parse_integer(const char *str) 5518 { 5519 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5520 const char *orig; 5521 int n; 5522 char c; 5523 5524 orig = str; 5525 n = 0; 5526 for (c = *str; c != '\0'; c = *++str) { 5527 if (c < '0' || c > '9') 5528 return (-1); 5529 5530 n *= RADIX; 5531 n += c - '0'; 5532 } 5533 5534 /* Make sure we actually parsed something. */ 5535 if (str == orig) 5536 return (-1); 5537 return (n); 5538 } 5539 5540 static void 5541 print_usage(const char *argv0) 5542 { 5543 5544 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5545 "\n" 5546 "Options:\n" 5547 " -h Display this help message\n" 5548 " -p Search in PATH for named binary\n" 5549 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5550 " -- End of RTLD options\n" 5551 " <binary> Name of process to execute\n" 5552 " <args> Arguments to the executed process\n", argv0); 5553 } 5554 5555 /* 5556 * Overrides for libc_pic-provided functions. 5557 */ 5558 5559 int 5560 __getosreldate(void) 5561 { 5562 size_t len; 5563 int oid[2]; 5564 int error, osrel; 5565 5566 if (osreldate != 0) 5567 return (osreldate); 5568 5569 oid[0] = CTL_KERN; 5570 oid[1] = KERN_OSRELDATE; 5571 osrel = 0; 5572 len = sizeof(osrel); 5573 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5574 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5575 osreldate = osrel; 5576 return (osreldate); 5577 } 5578 5579 void 5580 exit(int status) 5581 { 5582 5583 _exit(status); 5584 } 5585 5586 void (*__cleanup)(void); 5587 int __isthreaded = 0; 5588 int _thread_autoinit_dummy_decl = 1; 5589 5590 /* 5591 * No unresolved symbols for rtld. 5592 */ 5593 void 5594 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5595 { 5596 } 5597 5598 const char * 5599 rtld_strerror(int errnum) 5600 { 5601 5602 if (errnum < 0 || errnum >= sys_nerr) 5603 return ("Unknown error"); 5604 return (sys_errlist[errnum]); 5605 } 5606