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 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 704 dump_relocations(obj_main); 705 exit (0); 706 } 707 708 ifunc_init(aux); 709 710 /* 711 * Setup TLS for main thread. This must be done after the 712 * relocations are processed, since tls initialization section 713 * might be the subject for relocations. 714 */ 715 dbg("initializing initial thread local storage"); 716 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 717 718 dbg("initializing key program variables"); 719 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 720 set_program_var("environ", env); 721 set_program_var("__elf_aux_vector", aux); 722 723 /* Make a list of init functions to call. */ 724 objlist_init(&initlist); 725 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 726 preload_tail, &initlist); 727 728 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 729 730 map_stacks_exec(NULL); 731 732 dbg("resolving ifuncs"); 733 if (resolve_objects_ifunc(obj_main, 734 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 735 NULL) == -1) 736 rtld_die(); 737 738 dbg("enforcing main obj relro"); 739 if (obj_enforce_relro(obj_main) == -1) 740 rtld_die(); 741 742 if (!obj_main->crt_no_init) { 743 /* 744 * Make sure we don't call the main program's init and fini 745 * functions for binaries linked with old crt1 which calls 746 * _init itself. 747 */ 748 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 749 obj_main->preinit_array = obj_main->init_array = 750 obj_main->fini_array = (Elf_Addr)NULL; 751 } 752 753 /* 754 * Execute MD initializers required before we call the objects' 755 * init functions. 756 */ 757 pre_init(); 758 759 wlock_acquire(rtld_bind_lock, &lockstate); 760 if (obj_main->crt_no_init) 761 preinit_main(); 762 objlist_call_init(&initlist, &lockstate); 763 _r_debug_postinit(&obj_main->linkmap); 764 objlist_clear(&initlist); 765 dbg("loading filtees"); 766 TAILQ_FOREACH(obj, &obj_list, next) { 767 if (obj->marker) 768 continue; 769 if (ld_loadfltr || obj->z_loadfltr) 770 load_filtees(obj, 0, &lockstate); 771 } 772 lock_release(rtld_bind_lock, &lockstate); 773 774 dbg("transferring control to program entry point = %p", obj_main->entry); 775 776 /* Return the exit procedure and the program entry point. */ 777 *exit_proc = rtld_exit; 778 *objp = obj_main; 779 return (func_ptr_type) obj_main->entry; 780 } 781 782 void * 783 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 784 { 785 void *ptr; 786 Elf_Addr target; 787 788 ptr = (void *)make_function_pointer(def, obj); 789 target = call_ifunc_resolver(ptr); 790 return ((void *)target); 791 } 792 793 /* 794 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 795 * Changes to this function should be applied there as well. 796 */ 797 Elf_Addr 798 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 799 { 800 const Elf_Rel *rel; 801 const Elf_Sym *def; 802 const Obj_Entry *defobj; 803 Elf_Addr *where; 804 Elf_Addr target; 805 RtldLockState lockstate; 806 807 rlock_acquire(rtld_bind_lock, &lockstate); 808 if (sigsetjmp(lockstate.env, 0) != 0) 809 lock_upgrade(rtld_bind_lock, &lockstate); 810 if (obj->pltrel) 811 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 812 else 813 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 814 815 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 816 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 817 NULL, &lockstate); 818 if (def == NULL) 819 rtld_die(); 820 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 821 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 822 else 823 target = (Elf_Addr)(defobj->relocbase + def->st_value); 824 825 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 826 defobj->strtab + def->st_name, basename(obj->path), 827 (void *)target, basename(defobj->path)); 828 829 /* 830 * Write the new contents for the jmpslot. Note that depending on 831 * architecture, the value which we need to return back to the 832 * lazy binding trampoline may or may not be the target 833 * address. The value returned from reloc_jmpslot() is the value 834 * that the trampoline needs. 835 */ 836 target = reloc_jmpslot(where, target, defobj, obj, rel); 837 lock_release(rtld_bind_lock, &lockstate); 838 return target; 839 } 840 841 /* 842 * Error reporting function. Use it like printf. If formats the message 843 * into a buffer, and sets things up so that the next call to dlerror() 844 * will return the message. 845 */ 846 void 847 _rtld_error(const char *fmt, ...) 848 { 849 static char buf[512]; 850 va_list ap; 851 852 va_start(ap, fmt); 853 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 854 error_message = buf; 855 va_end(ap); 856 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 857 } 858 859 /* 860 * Return a dynamically-allocated copy of the current error message, if any. 861 */ 862 static char * 863 errmsg_save(void) 864 { 865 return error_message == NULL ? NULL : xstrdup(error_message); 866 } 867 868 /* 869 * Restore the current error message from a copy which was previously saved 870 * by errmsg_save(). The copy is freed. 871 */ 872 static void 873 errmsg_restore(char *saved_msg) 874 { 875 if (saved_msg == NULL) 876 error_message = NULL; 877 else { 878 _rtld_error("%s", saved_msg); 879 free(saved_msg); 880 } 881 } 882 883 static const char * 884 basename(const char *name) 885 { 886 const char *p = strrchr(name, '/'); 887 return p != NULL ? p + 1 : name; 888 } 889 890 static struct utsname uts; 891 892 static char * 893 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 894 const char *subst, bool may_free) 895 { 896 char *p, *p1, *res, *resp; 897 int subst_len, kw_len, subst_count, old_len, new_len; 898 899 kw_len = strlen(kw); 900 901 /* 902 * First, count the number of the keyword occurrences, to 903 * preallocate the final string. 904 */ 905 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 906 p1 = strstr(p, kw); 907 if (p1 == NULL) 908 break; 909 } 910 911 /* 912 * If the keyword is not found, just return. 913 * 914 * Return non-substituted string if resolution failed. We 915 * cannot do anything more reasonable, the failure mode of the 916 * caller is unresolved library anyway. 917 */ 918 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 919 return (may_free ? real : xstrdup(real)); 920 if (obj != NULL) 921 subst = obj->origin_path; 922 923 /* 924 * There is indeed something to substitute. Calculate the 925 * length of the resulting string, and allocate it. 926 */ 927 subst_len = strlen(subst); 928 old_len = strlen(real); 929 new_len = old_len + (subst_len - kw_len) * subst_count; 930 res = xmalloc(new_len + 1); 931 932 /* 933 * Now, execute the substitution loop. 934 */ 935 for (p = real, resp = res, *resp = '\0';;) { 936 p1 = strstr(p, kw); 937 if (p1 != NULL) { 938 /* Copy the prefix before keyword. */ 939 memcpy(resp, p, p1 - p); 940 resp += p1 - p; 941 /* Keyword replacement. */ 942 memcpy(resp, subst, subst_len); 943 resp += subst_len; 944 *resp = '\0'; 945 p = p1 + kw_len; 946 } else 947 break; 948 } 949 950 /* Copy to the end of string and finish. */ 951 strcat(resp, p); 952 if (may_free) 953 free(real); 954 return (res); 955 } 956 957 static char * 958 origin_subst(Obj_Entry *obj, const char *real) 959 { 960 char *res1, *res2, *res3, *res4; 961 962 if (obj == NULL || !trust) 963 return (xstrdup(real)); 964 if (uts.sysname[0] == '\0') { 965 if (uname(&uts) != 0) { 966 _rtld_error("utsname failed: %d", errno); 967 return (NULL); 968 } 969 } 970 /* __DECONST is safe here since without may_free real is unchanged */ 971 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 972 false); 973 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 974 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 975 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 976 return (res4); 977 } 978 979 void 980 rtld_die(void) 981 { 982 const char *msg = dlerror(); 983 984 if (msg == NULL) 985 msg = "Fatal error"; 986 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 987 rtld_fdputstr(STDERR_FILENO, msg); 988 rtld_fdputchar(STDERR_FILENO, '\n'); 989 _exit(1); 990 } 991 992 /* 993 * Process a shared object's DYNAMIC section, and save the important 994 * information in its Obj_Entry structure. 995 */ 996 static void 997 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 998 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 999 { 1000 const Elf_Dyn *dynp; 1001 Needed_Entry **needed_tail = &obj->needed; 1002 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1003 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1004 const Elf_Hashelt *hashtab; 1005 const Elf32_Word *hashval; 1006 Elf32_Word bkt, nmaskwords; 1007 int bloom_size32; 1008 int plttype = DT_REL; 1009 1010 *dyn_rpath = NULL; 1011 *dyn_soname = NULL; 1012 *dyn_runpath = NULL; 1013 1014 obj->bind_now = false; 1015 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1016 switch (dynp->d_tag) { 1017 1018 case DT_REL: 1019 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1020 break; 1021 1022 case DT_RELSZ: 1023 obj->relsize = dynp->d_un.d_val; 1024 break; 1025 1026 case DT_RELENT: 1027 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1028 break; 1029 1030 case DT_JMPREL: 1031 obj->pltrel = (const Elf_Rel *) 1032 (obj->relocbase + dynp->d_un.d_ptr); 1033 break; 1034 1035 case DT_PLTRELSZ: 1036 obj->pltrelsize = dynp->d_un.d_val; 1037 break; 1038 1039 case DT_RELA: 1040 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_RELASZ: 1044 obj->relasize = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_RELAENT: 1048 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1049 break; 1050 1051 case DT_PLTREL: 1052 plttype = dynp->d_un.d_val; 1053 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1054 break; 1055 1056 case DT_SYMTAB: 1057 obj->symtab = (const Elf_Sym *) 1058 (obj->relocbase + dynp->d_un.d_ptr); 1059 break; 1060 1061 case DT_SYMENT: 1062 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1063 break; 1064 1065 case DT_STRTAB: 1066 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1067 break; 1068 1069 case DT_STRSZ: 1070 obj->strsize = dynp->d_un.d_val; 1071 break; 1072 1073 case DT_VERNEED: 1074 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1075 dynp->d_un.d_val); 1076 break; 1077 1078 case DT_VERNEEDNUM: 1079 obj->verneednum = dynp->d_un.d_val; 1080 break; 1081 1082 case DT_VERDEF: 1083 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1084 dynp->d_un.d_val); 1085 break; 1086 1087 case DT_VERDEFNUM: 1088 obj->verdefnum = dynp->d_un.d_val; 1089 break; 1090 1091 case DT_VERSYM: 1092 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1093 dynp->d_un.d_val); 1094 break; 1095 1096 case DT_HASH: 1097 { 1098 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1099 dynp->d_un.d_ptr); 1100 obj->nbuckets = hashtab[0]; 1101 obj->nchains = hashtab[1]; 1102 obj->buckets = hashtab + 2; 1103 obj->chains = obj->buckets + obj->nbuckets; 1104 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1105 obj->buckets != NULL; 1106 } 1107 break; 1108 1109 case DT_GNU_HASH: 1110 { 1111 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1112 dynp->d_un.d_ptr); 1113 obj->nbuckets_gnu = hashtab[0]; 1114 obj->symndx_gnu = hashtab[1]; 1115 nmaskwords = hashtab[2]; 1116 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1117 obj->maskwords_bm_gnu = nmaskwords - 1; 1118 obj->shift2_gnu = hashtab[3]; 1119 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1120 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1121 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1122 obj->symndx_gnu; 1123 /* Number of bitmask words is required to be power of 2 */ 1124 obj->valid_hash_gnu = powerof2(nmaskwords) && 1125 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1126 } 1127 break; 1128 1129 case DT_NEEDED: 1130 if (!obj->rtld) { 1131 Needed_Entry *nep = NEW(Needed_Entry); 1132 nep->name = dynp->d_un.d_val; 1133 nep->obj = NULL; 1134 nep->next = NULL; 1135 1136 *needed_tail = nep; 1137 needed_tail = &nep->next; 1138 } 1139 break; 1140 1141 case DT_FILTER: 1142 if (!obj->rtld) { 1143 Needed_Entry *nep = NEW(Needed_Entry); 1144 nep->name = dynp->d_un.d_val; 1145 nep->obj = NULL; 1146 nep->next = NULL; 1147 1148 *needed_filtees_tail = nep; 1149 needed_filtees_tail = &nep->next; 1150 } 1151 break; 1152 1153 case DT_AUXILIARY: 1154 if (!obj->rtld) { 1155 Needed_Entry *nep = NEW(Needed_Entry); 1156 nep->name = dynp->d_un.d_val; 1157 nep->obj = NULL; 1158 nep->next = NULL; 1159 1160 *needed_aux_filtees_tail = nep; 1161 needed_aux_filtees_tail = &nep->next; 1162 } 1163 break; 1164 1165 case DT_PLTGOT: 1166 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1167 break; 1168 1169 case DT_TEXTREL: 1170 obj->textrel = true; 1171 break; 1172 1173 case DT_SYMBOLIC: 1174 obj->symbolic = true; 1175 break; 1176 1177 case DT_RPATH: 1178 /* 1179 * We have to wait until later to process this, because we 1180 * might not have gotten the address of the string table yet. 1181 */ 1182 *dyn_rpath = dynp; 1183 break; 1184 1185 case DT_SONAME: 1186 *dyn_soname = dynp; 1187 break; 1188 1189 case DT_RUNPATH: 1190 *dyn_runpath = dynp; 1191 break; 1192 1193 case DT_INIT: 1194 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1195 break; 1196 1197 case DT_PREINIT_ARRAY: 1198 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1199 break; 1200 1201 case DT_PREINIT_ARRAYSZ: 1202 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1203 break; 1204 1205 case DT_INIT_ARRAY: 1206 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1207 break; 1208 1209 case DT_INIT_ARRAYSZ: 1210 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1211 break; 1212 1213 case DT_FINI: 1214 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1215 break; 1216 1217 case DT_FINI_ARRAY: 1218 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1219 break; 1220 1221 case DT_FINI_ARRAYSZ: 1222 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1223 break; 1224 1225 /* 1226 * Don't process DT_DEBUG on MIPS as the dynamic section 1227 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1228 */ 1229 1230 #ifndef __mips__ 1231 case DT_DEBUG: 1232 if (!early) 1233 dbg("Filling in DT_DEBUG entry"); 1234 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1235 break; 1236 #endif 1237 1238 case DT_FLAGS: 1239 if (dynp->d_un.d_val & DF_ORIGIN) 1240 obj->z_origin = true; 1241 if (dynp->d_un.d_val & DF_SYMBOLIC) 1242 obj->symbolic = true; 1243 if (dynp->d_un.d_val & DF_TEXTREL) 1244 obj->textrel = true; 1245 if (dynp->d_un.d_val & DF_BIND_NOW) 1246 obj->bind_now = true; 1247 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1248 ;*/ 1249 break; 1250 #ifdef __mips__ 1251 case DT_MIPS_LOCAL_GOTNO: 1252 obj->local_gotno = dynp->d_un.d_val; 1253 break; 1254 1255 case DT_MIPS_SYMTABNO: 1256 obj->symtabno = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_MIPS_GOTSYM: 1260 obj->gotsym = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_RLD_MAP: 1264 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1265 break; 1266 1267 case DT_MIPS_RLD_MAP_REL: 1268 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1269 // section relative to the address of the tag itself. 1270 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1271 (Elf_Addr) &r_debug; 1272 break; 1273 1274 case DT_MIPS_PLTGOT: 1275 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1276 dynp->d_un.d_ptr); 1277 break; 1278 1279 #endif 1280 1281 #ifdef __powerpc64__ 1282 case DT_PPC64_GLINK: 1283 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1284 break; 1285 #endif 1286 1287 case DT_FLAGS_1: 1288 if (dynp->d_un.d_val & DF_1_NOOPEN) 1289 obj->z_noopen = true; 1290 if (dynp->d_un.d_val & DF_1_ORIGIN) 1291 obj->z_origin = true; 1292 if (dynp->d_un.d_val & DF_1_GLOBAL) 1293 obj->z_global = true; 1294 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1295 obj->bind_now = true; 1296 if (dynp->d_un.d_val & DF_1_NODELETE) 1297 obj->z_nodelete = true; 1298 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1299 obj->z_loadfltr = true; 1300 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1301 obj->z_interpose = true; 1302 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1303 obj->z_nodeflib = true; 1304 break; 1305 1306 default: 1307 if (!early) { 1308 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1309 (long)dynp->d_tag); 1310 } 1311 break; 1312 } 1313 } 1314 1315 obj->traced = false; 1316 1317 if (plttype == DT_RELA) { 1318 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1319 obj->pltrel = NULL; 1320 obj->pltrelasize = obj->pltrelsize; 1321 obj->pltrelsize = 0; 1322 } 1323 1324 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1325 if (obj->valid_hash_sysv) 1326 obj->dynsymcount = obj->nchains; 1327 else if (obj->valid_hash_gnu) { 1328 obj->dynsymcount = 0; 1329 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1330 if (obj->buckets_gnu[bkt] == 0) 1331 continue; 1332 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1333 do 1334 obj->dynsymcount++; 1335 while ((*hashval++ & 1u) == 0); 1336 } 1337 obj->dynsymcount += obj->symndx_gnu; 1338 } 1339 } 1340 1341 static bool 1342 obj_resolve_origin(Obj_Entry *obj) 1343 { 1344 1345 if (obj->origin_path != NULL) 1346 return (true); 1347 obj->origin_path = xmalloc(PATH_MAX); 1348 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1349 } 1350 1351 static void 1352 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1353 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1354 { 1355 1356 if (obj->z_origin && !obj_resolve_origin(obj)) 1357 rtld_die(); 1358 1359 if (dyn_runpath != NULL) { 1360 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1361 obj->runpath = origin_subst(obj, obj->runpath); 1362 } else if (dyn_rpath != NULL) { 1363 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1364 obj->rpath = origin_subst(obj, obj->rpath); 1365 } 1366 if (dyn_soname != NULL) 1367 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1368 } 1369 1370 static void 1371 digest_dynamic(Obj_Entry *obj, int early) 1372 { 1373 const Elf_Dyn *dyn_rpath; 1374 const Elf_Dyn *dyn_soname; 1375 const Elf_Dyn *dyn_runpath; 1376 1377 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1378 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1379 } 1380 1381 /* 1382 * Process a shared object's program header. This is used only for the 1383 * main program, when the kernel has already loaded the main program 1384 * into memory before calling the dynamic linker. It creates and 1385 * returns an Obj_Entry structure. 1386 */ 1387 static Obj_Entry * 1388 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1389 { 1390 Obj_Entry *obj; 1391 const Elf_Phdr *phlimit = phdr + phnum; 1392 const Elf_Phdr *ph; 1393 Elf_Addr note_start, note_end; 1394 int nsegs = 0; 1395 1396 obj = obj_new(); 1397 for (ph = phdr; ph < phlimit; ph++) { 1398 if (ph->p_type != PT_PHDR) 1399 continue; 1400 1401 obj->phdr = phdr; 1402 obj->phsize = ph->p_memsz; 1403 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1404 break; 1405 } 1406 1407 obj->stack_flags = PF_X | PF_R | PF_W; 1408 1409 for (ph = phdr; ph < phlimit; ph++) { 1410 switch (ph->p_type) { 1411 1412 case PT_INTERP: 1413 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1414 break; 1415 1416 case PT_LOAD: 1417 if (nsegs == 0) { /* First load segment */ 1418 obj->vaddrbase = trunc_page(ph->p_vaddr); 1419 obj->mapbase = obj->vaddrbase + obj->relocbase; 1420 } else { /* Last load segment */ 1421 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1422 obj->vaddrbase; 1423 } 1424 nsegs++; 1425 break; 1426 1427 case PT_DYNAMIC: 1428 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1429 break; 1430 1431 case PT_TLS: 1432 obj->tlsindex = 1; 1433 obj->tlssize = ph->p_memsz; 1434 obj->tlsalign = ph->p_align; 1435 obj->tlsinitsize = ph->p_filesz; 1436 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1437 break; 1438 1439 case PT_GNU_STACK: 1440 obj->stack_flags = ph->p_flags; 1441 break; 1442 1443 case PT_GNU_RELRO: 1444 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1445 obj->relro_size = round_page(ph->p_memsz); 1446 break; 1447 1448 case PT_NOTE: 1449 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1450 note_end = note_start + ph->p_filesz; 1451 digest_notes(obj, note_start, note_end); 1452 break; 1453 } 1454 } 1455 if (nsegs < 1) { 1456 _rtld_error("%s: too few PT_LOAD segments", path); 1457 return NULL; 1458 } 1459 1460 obj->entry = entry; 1461 return obj; 1462 } 1463 1464 void 1465 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1466 { 1467 const Elf_Note *note; 1468 const char *note_name; 1469 uintptr_t p; 1470 1471 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1472 note = (const Elf_Note *)((const char *)(note + 1) + 1473 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1474 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1475 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1476 note->n_descsz != sizeof(int32_t)) 1477 continue; 1478 if (note->n_type != NT_FREEBSD_ABI_TAG && 1479 note->n_type != NT_FREEBSD_NOINIT_TAG) 1480 continue; 1481 note_name = (const char *)(note + 1); 1482 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1483 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1484 continue; 1485 switch (note->n_type) { 1486 case NT_FREEBSD_ABI_TAG: 1487 /* FreeBSD osrel note */ 1488 p = (uintptr_t)(note + 1); 1489 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1490 obj->osrel = *(const int32_t *)(p); 1491 dbg("note osrel %d", obj->osrel); 1492 break; 1493 case NT_FREEBSD_NOINIT_TAG: 1494 /* FreeBSD 'crt does not call init' note */ 1495 obj->crt_no_init = true; 1496 dbg("note crt_no_init"); 1497 break; 1498 } 1499 } 1500 } 1501 1502 static Obj_Entry * 1503 dlcheck(void *handle) 1504 { 1505 Obj_Entry *obj; 1506 1507 TAILQ_FOREACH(obj, &obj_list, next) { 1508 if (obj == (Obj_Entry *) handle) 1509 break; 1510 } 1511 1512 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1513 _rtld_error("Invalid shared object handle %p", handle); 1514 return NULL; 1515 } 1516 return obj; 1517 } 1518 1519 /* 1520 * If the given object is already in the donelist, return true. Otherwise 1521 * add the object to the list and return false. 1522 */ 1523 static bool 1524 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1525 { 1526 unsigned int i; 1527 1528 for (i = 0; i < dlp->num_used; i++) 1529 if (dlp->objs[i] == obj) 1530 return true; 1531 /* 1532 * Our donelist allocation should always be sufficient. But if 1533 * our threads locking isn't working properly, more shared objects 1534 * could have been loaded since we allocated the list. That should 1535 * never happen, but we'll handle it properly just in case it does. 1536 */ 1537 if (dlp->num_used < dlp->num_alloc) 1538 dlp->objs[dlp->num_used++] = obj; 1539 return false; 1540 } 1541 1542 /* 1543 * Hash function for symbol table lookup. Don't even think about changing 1544 * this. It is specified by the System V ABI. 1545 */ 1546 unsigned long 1547 elf_hash(const char *name) 1548 { 1549 const unsigned char *p = (const unsigned char *) name; 1550 unsigned long h = 0; 1551 unsigned long g; 1552 1553 while (*p != '\0') { 1554 h = (h << 4) + *p++; 1555 if ((g = h & 0xf0000000) != 0) 1556 h ^= g >> 24; 1557 h &= ~g; 1558 } 1559 return h; 1560 } 1561 1562 /* 1563 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1564 * unsigned in case it's implemented with a wider type. 1565 */ 1566 static uint32_t 1567 gnu_hash(const char *s) 1568 { 1569 uint32_t h; 1570 unsigned char c; 1571 1572 h = 5381; 1573 for (c = *s; c != '\0'; c = *++s) 1574 h = h * 33 + c; 1575 return (h & 0xffffffff); 1576 } 1577 1578 1579 /* 1580 * Find the library with the given name, and return its full pathname. 1581 * The returned string is dynamically allocated. Generates an error 1582 * message and returns NULL if the library cannot be found. 1583 * 1584 * If the second argument is non-NULL, then it refers to an already- 1585 * loaded shared object, whose library search path will be searched. 1586 * 1587 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1588 * descriptor (which is close-on-exec) will be passed out via the third 1589 * argument. 1590 * 1591 * The search order is: 1592 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1593 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1594 * LD_LIBRARY_PATH 1595 * DT_RUNPATH in the referencing file 1596 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1597 * from list) 1598 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1599 * 1600 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1601 */ 1602 static char * 1603 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1604 { 1605 char *pathname, *refobj_path; 1606 const char *name; 1607 bool nodeflib, objgiven; 1608 1609 objgiven = refobj != NULL; 1610 1611 if (libmap_disable || !objgiven || 1612 (name = lm_find(refobj->path, xname)) == NULL) 1613 name = xname; 1614 1615 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1616 if (name[0] != '/' && !trust) { 1617 _rtld_error("Absolute pathname required " 1618 "for shared object \"%s\"", name); 1619 return (NULL); 1620 } 1621 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1622 __DECONST(char *, name))); 1623 } 1624 1625 dbg(" Searching for \"%s\"", name); 1626 refobj_path = objgiven ? refobj->path : NULL; 1627 1628 /* 1629 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1630 * back to pre-conforming behaviour if user requested so with 1631 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1632 * nodeflib. 1633 */ 1634 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1635 pathname = search_library_path(name, ld_library_path, 1636 refobj_path, fdp); 1637 if (pathname != NULL) 1638 return (pathname); 1639 if (refobj != NULL) { 1640 pathname = search_library_path(name, refobj->rpath, 1641 refobj_path, fdp); 1642 if (pathname != NULL) 1643 return (pathname); 1644 } 1645 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 pathname = search_library_path(name, gethints(false), 1649 refobj_path, fdp); 1650 if (pathname != NULL) 1651 return (pathname); 1652 pathname = search_library_path(name, ld_standard_library_path, 1653 refobj_path, fdp); 1654 if (pathname != NULL) 1655 return (pathname); 1656 } else { 1657 nodeflib = objgiven ? refobj->z_nodeflib : false; 1658 if (objgiven) { 1659 pathname = search_library_path(name, refobj->rpath, 1660 refobj->path, fdp); 1661 if (pathname != NULL) 1662 return (pathname); 1663 } 1664 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1665 pathname = search_library_path(name, obj_main->rpath, 1666 refobj_path, fdp); 1667 if (pathname != NULL) 1668 return (pathname); 1669 } 1670 pathname = search_library_path(name, ld_library_path, 1671 refobj_path, fdp); 1672 if (pathname != NULL) 1673 return (pathname); 1674 if (objgiven) { 1675 pathname = search_library_path(name, refobj->runpath, 1676 refobj_path, fdp); 1677 if (pathname != NULL) 1678 return (pathname); 1679 } 1680 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1681 if (pathname != NULL) 1682 return (pathname); 1683 pathname = search_library_path(name, gethints(nodeflib), 1684 refobj_path, fdp); 1685 if (pathname != NULL) 1686 return (pathname); 1687 if (objgiven && !nodeflib) { 1688 pathname = search_library_path(name, 1689 ld_standard_library_path, refobj_path, fdp); 1690 if (pathname != NULL) 1691 return (pathname); 1692 } 1693 } 1694 1695 if (objgiven && refobj->path != NULL) { 1696 _rtld_error("Shared object \"%s\" not found, " 1697 "required by \"%s\"", name, basename(refobj->path)); 1698 } else { 1699 _rtld_error("Shared object \"%s\" not found", name); 1700 } 1701 return (NULL); 1702 } 1703 1704 /* 1705 * Given a symbol number in a referencing object, find the corresponding 1706 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1707 * no definition was found. Returns a pointer to the Obj_Entry of the 1708 * defining object via the reference parameter DEFOBJ_OUT. 1709 */ 1710 const Elf_Sym * 1711 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1712 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1713 RtldLockState *lockstate) 1714 { 1715 const Elf_Sym *ref; 1716 const Elf_Sym *def; 1717 const Obj_Entry *defobj; 1718 const Ver_Entry *ve; 1719 SymLook req; 1720 const char *name; 1721 int res; 1722 1723 /* 1724 * If we have already found this symbol, get the information from 1725 * the cache. 1726 */ 1727 if (symnum >= refobj->dynsymcount) 1728 return NULL; /* Bad object */ 1729 if (cache != NULL && cache[symnum].sym != NULL) { 1730 *defobj_out = cache[symnum].obj; 1731 return cache[symnum].sym; 1732 } 1733 1734 ref = refobj->symtab + symnum; 1735 name = refobj->strtab + ref->st_name; 1736 def = NULL; 1737 defobj = NULL; 1738 ve = NULL; 1739 1740 /* 1741 * We don't have to do a full scale lookup if the symbol is local. 1742 * We know it will bind to the instance in this load module; to 1743 * which we already have a pointer (ie ref). By not doing a lookup, 1744 * we not only improve performance, but it also avoids unresolvable 1745 * symbols when local symbols are not in the hash table. This has 1746 * been seen with the ia64 toolchain. 1747 */ 1748 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1749 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1750 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1751 symnum); 1752 } 1753 symlook_init(&req, name); 1754 req.flags = flags; 1755 ve = req.ventry = fetch_ventry(refobj, symnum); 1756 req.lockstate = lockstate; 1757 res = symlook_default(&req, refobj); 1758 if (res == 0) { 1759 def = req.sym_out; 1760 defobj = req.defobj_out; 1761 } 1762 } else { 1763 def = ref; 1764 defobj = refobj; 1765 } 1766 1767 /* 1768 * If we found no definition and the reference is weak, treat the 1769 * symbol as having the value zero. 1770 */ 1771 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1772 def = &sym_zero; 1773 defobj = obj_main; 1774 } 1775 1776 if (def != NULL) { 1777 *defobj_out = defobj; 1778 /* Record the information in the cache to avoid subsequent lookups. */ 1779 if (cache != NULL) { 1780 cache[symnum].sym = def; 1781 cache[symnum].obj = defobj; 1782 } 1783 } else { 1784 if (refobj != &obj_rtld) 1785 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1786 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1787 } 1788 return def; 1789 } 1790 1791 /* 1792 * Return the search path from the ldconfig hints file, reading it if 1793 * necessary. If nostdlib is true, then the default search paths are 1794 * not added to result. 1795 * 1796 * Returns NULL if there are problems with the hints file, 1797 * or if the search path there is empty. 1798 */ 1799 static const char * 1800 gethints(bool nostdlib) 1801 { 1802 static char *filtered_path; 1803 static const char *hints; 1804 static struct elfhints_hdr hdr; 1805 struct fill_search_info_args sargs, hargs; 1806 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1807 struct dl_serpath *SLPpath, *hintpath; 1808 char *p; 1809 struct stat hint_stat; 1810 unsigned int SLPndx, hintndx, fndx, fcount; 1811 int fd; 1812 size_t flen; 1813 uint32_t dl; 1814 bool skip; 1815 1816 /* First call, read the hints file */ 1817 if (hints == NULL) { 1818 /* Keep from trying again in case the hints file is bad. */ 1819 hints = ""; 1820 1821 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1822 return (NULL); 1823 1824 /* 1825 * Check of hdr.dirlistlen value against type limit 1826 * intends to pacify static analyzers. Further 1827 * paranoia leads to checks that dirlist is fully 1828 * contained in the file range. 1829 */ 1830 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1831 hdr.magic != ELFHINTS_MAGIC || 1832 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1833 fstat(fd, &hint_stat) == -1) { 1834 cleanup1: 1835 close(fd); 1836 hdr.dirlistlen = 0; 1837 return (NULL); 1838 } 1839 dl = hdr.strtab; 1840 if (dl + hdr.dirlist < dl) 1841 goto cleanup1; 1842 dl += hdr.dirlist; 1843 if (dl + hdr.dirlistlen < dl) 1844 goto cleanup1; 1845 dl += hdr.dirlistlen; 1846 if (dl > hint_stat.st_size) 1847 goto cleanup1; 1848 p = xmalloc(hdr.dirlistlen + 1); 1849 if (pread(fd, p, hdr.dirlistlen + 1, 1850 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1851 p[hdr.dirlistlen] != '\0') { 1852 free(p); 1853 goto cleanup1; 1854 } 1855 hints = p; 1856 close(fd); 1857 } 1858 1859 /* 1860 * If caller agreed to receive list which includes the default 1861 * paths, we are done. Otherwise, if we still did not 1862 * calculated filtered result, do it now. 1863 */ 1864 if (!nostdlib) 1865 return (hints[0] != '\0' ? hints : NULL); 1866 if (filtered_path != NULL) 1867 goto filt_ret; 1868 1869 /* 1870 * Obtain the list of all configured search paths, and the 1871 * list of the default paths. 1872 * 1873 * First estimate the size of the results. 1874 */ 1875 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1876 smeta.dls_cnt = 0; 1877 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1878 hmeta.dls_cnt = 0; 1879 1880 sargs.request = RTLD_DI_SERINFOSIZE; 1881 sargs.serinfo = &smeta; 1882 hargs.request = RTLD_DI_SERINFOSIZE; 1883 hargs.serinfo = &hmeta; 1884 1885 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1886 &sargs); 1887 path_enumerate(hints, fill_search_info, NULL, &hargs); 1888 1889 SLPinfo = xmalloc(smeta.dls_size); 1890 hintinfo = xmalloc(hmeta.dls_size); 1891 1892 /* 1893 * Next fetch both sets of paths. 1894 */ 1895 sargs.request = RTLD_DI_SERINFO; 1896 sargs.serinfo = SLPinfo; 1897 sargs.serpath = &SLPinfo->dls_serpath[0]; 1898 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1899 1900 hargs.request = RTLD_DI_SERINFO; 1901 hargs.serinfo = hintinfo; 1902 hargs.serpath = &hintinfo->dls_serpath[0]; 1903 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1904 1905 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1906 &sargs); 1907 path_enumerate(hints, fill_search_info, NULL, &hargs); 1908 1909 /* 1910 * Now calculate the difference between two sets, by excluding 1911 * standard paths from the full set. 1912 */ 1913 fndx = 0; 1914 fcount = 0; 1915 filtered_path = xmalloc(hdr.dirlistlen + 1); 1916 hintpath = &hintinfo->dls_serpath[0]; 1917 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1918 skip = false; 1919 SLPpath = &SLPinfo->dls_serpath[0]; 1920 /* 1921 * Check each standard path against current. 1922 */ 1923 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1924 /* matched, skip the path */ 1925 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1926 skip = true; 1927 break; 1928 } 1929 } 1930 if (skip) 1931 continue; 1932 /* 1933 * Not matched against any standard path, add the path 1934 * to result. Separate consequtive paths with ':'. 1935 */ 1936 if (fcount > 0) { 1937 filtered_path[fndx] = ':'; 1938 fndx++; 1939 } 1940 fcount++; 1941 flen = strlen(hintpath->dls_name); 1942 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1943 fndx += flen; 1944 } 1945 filtered_path[fndx] = '\0'; 1946 1947 free(SLPinfo); 1948 free(hintinfo); 1949 1950 filt_ret: 1951 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1952 } 1953 1954 static void 1955 init_dag(Obj_Entry *root) 1956 { 1957 const Needed_Entry *needed; 1958 const Objlist_Entry *elm; 1959 DoneList donelist; 1960 1961 if (root->dag_inited) 1962 return; 1963 donelist_init(&donelist); 1964 1965 /* Root object belongs to own DAG. */ 1966 objlist_push_tail(&root->dldags, root); 1967 objlist_push_tail(&root->dagmembers, root); 1968 donelist_check(&donelist, root); 1969 1970 /* 1971 * Add dependencies of root object to DAG in breadth order 1972 * by exploiting the fact that each new object get added 1973 * to the tail of the dagmembers list. 1974 */ 1975 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1976 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1977 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1978 continue; 1979 objlist_push_tail(&needed->obj->dldags, root); 1980 objlist_push_tail(&root->dagmembers, needed->obj); 1981 } 1982 } 1983 root->dag_inited = true; 1984 } 1985 1986 static void 1987 init_marker(Obj_Entry *marker) 1988 { 1989 1990 bzero(marker, sizeof(*marker)); 1991 marker->marker = true; 1992 } 1993 1994 Obj_Entry * 1995 globallist_curr(const Obj_Entry *obj) 1996 { 1997 1998 for (;;) { 1999 if (obj == NULL) 2000 return (NULL); 2001 if (!obj->marker) 2002 return (__DECONST(Obj_Entry *, obj)); 2003 obj = TAILQ_PREV(obj, obj_entry_q, next); 2004 } 2005 } 2006 2007 Obj_Entry * 2008 globallist_next(const Obj_Entry *obj) 2009 { 2010 2011 for (;;) { 2012 obj = TAILQ_NEXT(obj, next); 2013 if (obj == NULL) 2014 return (NULL); 2015 if (!obj->marker) 2016 return (__DECONST(Obj_Entry *, obj)); 2017 } 2018 } 2019 2020 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2021 static void 2022 hold_object(Obj_Entry *obj) 2023 { 2024 2025 obj->holdcount++; 2026 } 2027 2028 static void 2029 unhold_object(Obj_Entry *obj) 2030 { 2031 2032 assert(obj->holdcount > 0); 2033 if (--obj->holdcount == 0 && obj->unholdfree) 2034 release_object(obj); 2035 } 2036 2037 static void 2038 process_z(Obj_Entry *root) 2039 { 2040 const Objlist_Entry *elm; 2041 Obj_Entry *obj; 2042 2043 /* 2044 * Walk over object DAG and process every dependent object 2045 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2046 * to grow their own DAG. 2047 * 2048 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2049 * symlook_global() to work. 2050 * 2051 * For DF_1_NODELETE, the DAG should have its reference upped. 2052 */ 2053 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2054 obj = elm->obj; 2055 if (obj == NULL) 2056 continue; 2057 if (obj->z_nodelete && !obj->ref_nodel) { 2058 dbg("obj %s -z nodelete", obj->path); 2059 init_dag(obj); 2060 ref_dag(obj); 2061 obj->ref_nodel = true; 2062 } 2063 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2064 dbg("obj %s -z global", obj->path); 2065 objlist_push_tail(&list_global, obj); 2066 init_dag(obj); 2067 } 2068 } 2069 } 2070 /* 2071 * Initialize the dynamic linker. The argument is the address at which 2072 * the dynamic linker has been mapped into memory. The primary task of 2073 * this function is to relocate the dynamic linker. 2074 */ 2075 static void 2076 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2077 { 2078 Obj_Entry objtmp; /* Temporary rtld object */ 2079 const Elf_Ehdr *ehdr; 2080 const Elf_Dyn *dyn_rpath; 2081 const Elf_Dyn *dyn_soname; 2082 const Elf_Dyn *dyn_runpath; 2083 2084 #ifdef RTLD_INIT_PAGESIZES_EARLY 2085 /* The page size is required by the dynamic memory allocator. */ 2086 init_pagesizes(aux_info); 2087 #endif 2088 2089 /* 2090 * Conjure up an Obj_Entry structure for the dynamic linker. 2091 * 2092 * The "path" member can't be initialized yet because string constants 2093 * cannot yet be accessed. Below we will set it correctly. 2094 */ 2095 memset(&objtmp, 0, sizeof(objtmp)); 2096 objtmp.path = NULL; 2097 objtmp.rtld = true; 2098 objtmp.mapbase = mapbase; 2099 #ifdef PIC 2100 objtmp.relocbase = mapbase; 2101 #endif 2102 2103 objtmp.dynamic = rtld_dynamic(&objtmp); 2104 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2105 assert(objtmp.needed == NULL); 2106 #if !defined(__mips__) 2107 /* MIPS has a bogus DT_TEXTREL. */ 2108 assert(!objtmp.textrel); 2109 #endif 2110 /* 2111 * Temporarily put the dynamic linker entry into the object list, so 2112 * that symbols can be found. 2113 */ 2114 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2115 2116 ehdr = (Elf_Ehdr *)mapbase; 2117 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2118 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2119 2120 /* Initialize the object list. */ 2121 TAILQ_INIT(&obj_list); 2122 2123 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2124 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2125 2126 #ifndef RTLD_INIT_PAGESIZES_EARLY 2127 /* The page size is required by the dynamic memory allocator. */ 2128 init_pagesizes(aux_info); 2129 #endif 2130 2131 if (aux_info[AT_OSRELDATE] != NULL) 2132 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2133 2134 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2135 2136 /* Replace the path with a dynamically allocated copy. */ 2137 obj_rtld.path = xstrdup(ld_path_rtld); 2138 2139 r_debug.r_brk = r_debug_state; 2140 r_debug.r_state = RT_CONSISTENT; 2141 } 2142 2143 /* 2144 * Retrieve the array of supported page sizes. The kernel provides the page 2145 * sizes in increasing order. 2146 */ 2147 static void 2148 init_pagesizes(Elf_Auxinfo **aux_info) 2149 { 2150 static size_t psa[MAXPAGESIZES]; 2151 int mib[2]; 2152 size_t len, size; 2153 2154 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2155 NULL) { 2156 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2157 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2158 } else { 2159 len = 2; 2160 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2161 size = sizeof(psa); 2162 else { 2163 /* As a fallback, retrieve the base page size. */ 2164 size = sizeof(psa[0]); 2165 if (aux_info[AT_PAGESZ] != NULL) { 2166 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2167 goto psa_filled; 2168 } else { 2169 mib[0] = CTL_HW; 2170 mib[1] = HW_PAGESIZE; 2171 len = 2; 2172 } 2173 } 2174 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2175 _rtld_error("sysctl for hw.pagesize(s) failed"); 2176 rtld_die(); 2177 } 2178 psa_filled: 2179 pagesizes = psa; 2180 } 2181 npagesizes = size / sizeof(pagesizes[0]); 2182 /* Discard any invalid entries at the end of the array. */ 2183 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2184 npagesizes--; 2185 } 2186 2187 /* 2188 * Add the init functions from a needed object list (and its recursive 2189 * needed objects) to "list". This is not used directly; it is a helper 2190 * function for initlist_add_objects(). The write lock must be held 2191 * when this function is called. 2192 */ 2193 static void 2194 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2195 { 2196 /* Recursively process the successor needed objects. */ 2197 if (needed->next != NULL) 2198 initlist_add_neededs(needed->next, list); 2199 2200 /* Process the current needed object. */ 2201 if (needed->obj != NULL) 2202 initlist_add_objects(needed->obj, needed->obj, list); 2203 } 2204 2205 /* 2206 * Scan all of the DAGs rooted in the range of objects from "obj" to 2207 * "tail" and add their init functions to "list". This recurses over 2208 * the DAGs and ensure the proper init ordering such that each object's 2209 * needed libraries are initialized before the object itself. At the 2210 * same time, this function adds the objects to the global finalization 2211 * list "list_fini" in the opposite order. The write lock must be 2212 * held when this function is called. 2213 */ 2214 static void 2215 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2216 { 2217 Obj_Entry *nobj; 2218 2219 if (obj->init_scanned || obj->init_done) 2220 return; 2221 obj->init_scanned = true; 2222 2223 /* Recursively process the successor objects. */ 2224 nobj = globallist_next(obj); 2225 if (nobj != NULL && obj != tail) 2226 initlist_add_objects(nobj, tail, list); 2227 2228 /* Recursively process the needed objects. */ 2229 if (obj->needed != NULL) 2230 initlist_add_neededs(obj->needed, list); 2231 if (obj->needed_filtees != NULL) 2232 initlist_add_neededs(obj->needed_filtees, list); 2233 if (obj->needed_aux_filtees != NULL) 2234 initlist_add_neededs(obj->needed_aux_filtees, list); 2235 2236 /* Add the object to the init list. */ 2237 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2238 obj->init_array != (Elf_Addr)NULL) 2239 objlist_push_tail(list, obj); 2240 2241 /* Add the object to the global fini list in the reverse order. */ 2242 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2243 && !obj->on_fini_list) { 2244 objlist_push_head(&list_fini, obj); 2245 obj->on_fini_list = true; 2246 } 2247 } 2248 2249 #ifndef FPTR_TARGET 2250 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2251 #endif 2252 2253 static void 2254 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2255 { 2256 Needed_Entry *needed, *needed1; 2257 2258 for (needed = n; needed != NULL; needed = needed->next) { 2259 if (needed->obj != NULL) { 2260 dlclose_locked(needed->obj, lockstate); 2261 needed->obj = NULL; 2262 } 2263 } 2264 for (needed = n; needed != NULL; needed = needed1) { 2265 needed1 = needed->next; 2266 free(needed); 2267 } 2268 } 2269 2270 static void 2271 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2272 { 2273 2274 free_needed_filtees(obj->needed_filtees, lockstate); 2275 obj->needed_filtees = NULL; 2276 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2277 obj->needed_aux_filtees = NULL; 2278 obj->filtees_loaded = false; 2279 } 2280 2281 static void 2282 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2283 RtldLockState *lockstate) 2284 { 2285 2286 for (; needed != NULL; needed = needed->next) { 2287 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2288 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2289 RTLD_LOCAL, lockstate); 2290 } 2291 } 2292 2293 static void 2294 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2295 { 2296 2297 lock_restart_for_upgrade(lockstate); 2298 if (!obj->filtees_loaded) { 2299 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2300 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2301 obj->filtees_loaded = true; 2302 } 2303 } 2304 2305 static int 2306 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2307 { 2308 Obj_Entry *obj1; 2309 2310 for (; needed != NULL; needed = needed->next) { 2311 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2312 flags & ~RTLD_LO_NOLOAD); 2313 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2314 return (-1); 2315 } 2316 return (0); 2317 } 2318 2319 /* 2320 * Given a shared object, traverse its list of needed objects, and load 2321 * each of them. Returns 0 on success. Generates an error message and 2322 * returns -1 on failure. 2323 */ 2324 static int 2325 load_needed_objects(Obj_Entry *first, int flags) 2326 { 2327 Obj_Entry *obj; 2328 2329 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2330 if (obj->marker) 2331 continue; 2332 if (process_needed(obj, obj->needed, flags) == -1) 2333 return (-1); 2334 } 2335 return (0); 2336 } 2337 2338 static int 2339 load_preload_objects(void) 2340 { 2341 char *p = ld_preload; 2342 Obj_Entry *obj; 2343 static const char delim[] = " \t:;"; 2344 2345 if (p == NULL) 2346 return 0; 2347 2348 p += strspn(p, delim); 2349 while (*p != '\0') { 2350 size_t len = strcspn(p, delim); 2351 char savech; 2352 2353 savech = p[len]; 2354 p[len] = '\0'; 2355 obj = load_object(p, -1, NULL, 0); 2356 if (obj == NULL) 2357 return -1; /* XXX - cleanup */ 2358 obj->z_interpose = true; 2359 p[len] = savech; 2360 p += len; 2361 p += strspn(p, delim); 2362 } 2363 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2364 return 0; 2365 } 2366 2367 static const char * 2368 printable_path(const char *path) 2369 { 2370 2371 return (path == NULL ? "<unknown>" : path); 2372 } 2373 2374 /* 2375 * Load a shared object into memory, if it is not already loaded. The 2376 * object may be specified by name or by user-supplied file descriptor 2377 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2378 * duplicate is. 2379 * 2380 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2381 * on failure. 2382 */ 2383 static Obj_Entry * 2384 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2385 { 2386 Obj_Entry *obj; 2387 int fd; 2388 struct stat sb; 2389 char *path; 2390 2391 fd = -1; 2392 if (name != NULL) { 2393 TAILQ_FOREACH(obj, &obj_list, next) { 2394 if (obj->marker || obj->doomed) 2395 continue; 2396 if (object_match_name(obj, name)) 2397 return (obj); 2398 } 2399 2400 path = find_library(name, refobj, &fd); 2401 if (path == NULL) 2402 return (NULL); 2403 } else 2404 path = NULL; 2405 2406 if (fd >= 0) { 2407 /* 2408 * search_library_pathfds() opens a fresh file descriptor for the 2409 * library, so there is no need to dup(). 2410 */ 2411 } else if (fd_u == -1) { 2412 /* 2413 * If we didn't find a match by pathname, or the name is not 2414 * supplied, open the file and check again by device and inode. 2415 * This avoids false mismatches caused by multiple links or ".." 2416 * in pathnames. 2417 * 2418 * To avoid a race, we open the file and use fstat() rather than 2419 * using stat(). 2420 */ 2421 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2422 _rtld_error("Cannot open \"%s\"", path); 2423 free(path); 2424 return (NULL); 2425 } 2426 } else { 2427 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2428 if (fd == -1) { 2429 _rtld_error("Cannot dup fd"); 2430 free(path); 2431 return (NULL); 2432 } 2433 } 2434 if (fstat(fd, &sb) == -1) { 2435 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2436 close(fd); 2437 free(path); 2438 return NULL; 2439 } 2440 TAILQ_FOREACH(obj, &obj_list, next) { 2441 if (obj->marker || obj->doomed) 2442 continue; 2443 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2444 break; 2445 } 2446 if (obj != NULL && name != NULL) { 2447 object_add_name(obj, name); 2448 free(path); 2449 close(fd); 2450 return obj; 2451 } 2452 if (flags & RTLD_LO_NOLOAD) { 2453 free(path); 2454 close(fd); 2455 return (NULL); 2456 } 2457 2458 /* First use of this object, so we must map it in */ 2459 obj = do_load_object(fd, name, path, &sb, flags); 2460 if (obj == NULL) 2461 free(path); 2462 close(fd); 2463 2464 return obj; 2465 } 2466 2467 static Obj_Entry * 2468 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2469 int flags) 2470 { 2471 Obj_Entry *obj; 2472 struct statfs fs; 2473 2474 /* 2475 * but first, make sure that environment variables haven't been 2476 * used to circumvent the noexec flag on a filesystem. 2477 */ 2478 if (dangerous_ld_env) { 2479 if (fstatfs(fd, &fs) != 0) { 2480 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2481 return NULL; 2482 } 2483 if (fs.f_flags & MNT_NOEXEC) { 2484 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2485 return NULL; 2486 } 2487 } 2488 dbg("loading \"%s\"", printable_path(path)); 2489 obj = map_object(fd, printable_path(path), sbp); 2490 if (obj == NULL) 2491 return NULL; 2492 2493 /* 2494 * If DT_SONAME is present in the object, digest_dynamic2 already 2495 * added it to the object names. 2496 */ 2497 if (name != NULL) 2498 object_add_name(obj, name); 2499 obj->path = path; 2500 digest_dynamic(obj, 0); 2501 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2502 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2503 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2504 RTLD_LO_DLOPEN) { 2505 dbg("refusing to load non-loadable \"%s\"", obj->path); 2506 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2507 munmap(obj->mapbase, obj->mapsize); 2508 obj_free(obj); 2509 return (NULL); 2510 } 2511 2512 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2513 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2514 obj_count++; 2515 obj_loads++; 2516 linkmap_add(obj); /* for GDB & dlinfo() */ 2517 max_stack_flags |= obj->stack_flags; 2518 2519 dbg(" %p .. %p: %s", obj->mapbase, 2520 obj->mapbase + obj->mapsize - 1, obj->path); 2521 if (obj->textrel) 2522 dbg(" WARNING: %s has impure text", obj->path); 2523 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2524 obj->path); 2525 2526 return obj; 2527 } 2528 2529 static Obj_Entry * 2530 obj_from_addr(const void *addr) 2531 { 2532 Obj_Entry *obj; 2533 2534 TAILQ_FOREACH(obj, &obj_list, next) { 2535 if (obj->marker) 2536 continue; 2537 if (addr < (void *) obj->mapbase) 2538 continue; 2539 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2540 return obj; 2541 } 2542 return NULL; 2543 } 2544 2545 static void 2546 preinit_main(void) 2547 { 2548 Elf_Addr *preinit_addr; 2549 int index; 2550 2551 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2552 if (preinit_addr == NULL) 2553 return; 2554 2555 for (index = 0; index < obj_main->preinit_array_num; index++) { 2556 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2557 dbg("calling preinit function for %s at %p", obj_main->path, 2558 (void *)preinit_addr[index]); 2559 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2560 0, 0, obj_main->path); 2561 call_init_pointer(obj_main, preinit_addr[index]); 2562 } 2563 } 2564 } 2565 2566 /* 2567 * Call the finalization functions for each of the objects in "list" 2568 * belonging to the DAG of "root" and referenced once. If NULL "root" 2569 * is specified, every finalization function will be called regardless 2570 * of the reference count and the list elements won't be freed. All of 2571 * the objects are expected to have non-NULL fini functions. 2572 */ 2573 static void 2574 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2575 { 2576 Objlist_Entry *elm; 2577 char *saved_msg; 2578 Elf_Addr *fini_addr; 2579 int index; 2580 2581 assert(root == NULL || root->refcount == 1); 2582 2583 if (root != NULL) 2584 root->doomed = true; 2585 2586 /* 2587 * Preserve the current error message since a fini function might 2588 * call into the dynamic linker and overwrite it. 2589 */ 2590 saved_msg = errmsg_save(); 2591 do { 2592 STAILQ_FOREACH(elm, list, link) { 2593 if (root != NULL && (elm->obj->refcount != 1 || 2594 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2595 continue; 2596 /* Remove object from fini list to prevent recursive invocation. */ 2597 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2598 /* Ensure that new references cannot be acquired. */ 2599 elm->obj->doomed = true; 2600 2601 hold_object(elm->obj); 2602 lock_release(rtld_bind_lock, lockstate); 2603 /* 2604 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2605 * When this happens, DT_FINI_ARRAY is processed first. 2606 */ 2607 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2608 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2609 for (index = elm->obj->fini_array_num - 1; index >= 0; 2610 index--) { 2611 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2612 dbg("calling fini function for %s at %p", 2613 elm->obj->path, (void *)fini_addr[index]); 2614 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2615 (void *)fini_addr[index], 0, 0, elm->obj->path); 2616 call_initfini_pointer(elm->obj, fini_addr[index]); 2617 } 2618 } 2619 } 2620 if (elm->obj->fini != (Elf_Addr)NULL) { 2621 dbg("calling fini function for %s at %p", elm->obj->path, 2622 (void *)elm->obj->fini); 2623 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2624 0, 0, elm->obj->path); 2625 call_initfini_pointer(elm->obj, elm->obj->fini); 2626 } 2627 wlock_acquire(rtld_bind_lock, lockstate); 2628 unhold_object(elm->obj); 2629 /* No need to free anything if process is going down. */ 2630 if (root != NULL) 2631 free(elm); 2632 /* 2633 * We must restart the list traversal after every fini call 2634 * because a dlclose() call from the fini function or from 2635 * another thread might have modified the reference counts. 2636 */ 2637 break; 2638 } 2639 } while (elm != NULL); 2640 errmsg_restore(saved_msg); 2641 } 2642 2643 /* 2644 * Call the initialization functions for each of the objects in 2645 * "list". All of the objects are expected to have non-NULL init 2646 * functions. 2647 */ 2648 static void 2649 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2650 { 2651 Objlist_Entry *elm; 2652 Obj_Entry *obj; 2653 char *saved_msg; 2654 Elf_Addr *init_addr; 2655 int index; 2656 2657 /* 2658 * Clean init_scanned flag so that objects can be rechecked and 2659 * possibly initialized earlier if any of vectors called below 2660 * cause the change by using dlopen. 2661 */ 2662 TAILQ_FOREACH(obj, &obj_list, next) { 2663 if (obj->marker) 2664 continue; 2665 obj->init_scanned = false; 2666 } 2667 2668 /* 2669 * Preserve the current error message since an init function might 2670 * call into the dynamic linker and overwrite it. 2671 */ 2672 saved_msg = errmsg_save(); 2673 STAILQ_FOREACH(elm, list, link) { 2674 if (elm->obj->init_done) /* Initialized early. */ 2675 continue; 2676 /* 2677 * Race: other thread might try to use this object before current 2678 * one completes the initialization. Not much can be done here 2679 * without better locking. 2680 */ 2681 elm->obj->init_done = true; 2682 hold_object(elm->obj); 2683 lock_release(rtld_bind_lock, lockstate); 2684 2685 /* 2686 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2687 * When this happens, DT_INIT is processed first. 2688 */ 2689 if (elm->obj->init != (Elf_Addr)NULL) { 2690 dbg("calling init function for %s at %p", elm->obj->path, 2691 (void *)elm->obj->init); 2692 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2693 0, 0, elm->obj->path); 2694 call_initfini_pointer(elm->obj, elm->obj->init); 2695 } 2696 init_addr = (Elf_Addr *)elm->obj->init_array; 2697 if (init_addr != NULL) { 2698 for (index = 0; index < elm->obj->init_array_num; index++) { 2699 if (init_addr[index] != 0 && init_addr[index] != 1) { 2700 dbg("calling init function for %s at %p", elm->obj->path, 2701 (void *)init_addr[index]); 2702 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2703 (void *)init_addr[index], 0, 0, elm->obj->path); 2704 call_init_pointer(elm->obj, init_addr[index]); 2705 } 2706 } 2707 } 2708 wlock_acquire(rtld_bind_lock, lockstate); 2709 unhold_object(elm->obj); 2710 } 2711 errmsg_restore(saved_msg); 2712 } 2713 2714 static void 2715 objlist_clear(Objlist *list) 2716 { 2717 Objlist_Entry *elm; 2718 2719 while (!STAILQ_EMPTY(list)) { 2720 elm = STAILQ_FIRST(list); 2721 STAILQ_REMOVE_HEAD(list, link); 2722 free(elm); 2723 } 2724 } 2725 2726 static Objlist_Entry * 2727 objlist_find(Objlist *list, const Obj_Entry *obj) 2728 { 2729 Objlist_Entry *elm; 2730 2731 STAILQ_FOREACH(elm, list, link) 2732 if (elm->obj == obj) 2733 return elm; 2734 return NULL; 2735 } 2736 2737 static void 2738 objlist_init(Objlist *list) 2739 { 2740 STAILQ_INIT(list); 2741 } 2742 2743 static void 2744 objlist_push_head(Objlist *list, Obj_Entry *obj) 2745 { 2746 Objlist_Entry *elm; 2747 2748 elm = NEW(Objlist_Entry); 2749 elm->obj = obj; 2750 STAILQ_INSERT_HEAD(list, elm, link); 2751 } 2752 2753 static void 2754 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2755 { 2756 Objlist_Entry *elm; 2757 2758 elm = NEW(Objlist_Entry); 2759 elm->obj = obj; 2760 STAILQ_INSERT_TAIL(list, elm, link); 2761 } 2762 2763 static void 2764 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2765 { 2766 Objlist_Entry *elm, *listelm; 2767 2768 STAILQ_FOREACH(listelm, list, link) { 2769 if (listelm->obj == listobj) 2770 break; 2771 } 2772 elm = NEW(Objlist_Entry); 2773 elm->obj = obj; 2774 if (listelm != NULL) 2775 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2776 else 2777 STAILQ_INSERT_TAIL(list, elm, link); 2778 } 2779 2780 static void 2781 objlist_remove(Objlist *list, Obj_Entry *obj) 2782 { 2783 Objlist_Entry *elm; 2784 2785 if ((elm = objlist_find(list, obj)) != NULL) { 2786 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2787 free(elm); 2788 } 2789 } 2790 2791 /* 2792 * Relocate dag rooted in the specified object. 2793 * Returns 0 on success, or -1 on failure. 2794 */ 2795 2796 static int 2797 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2798 int flags, RtldLockState *lockstate) 2799 { 2800 Objlist_Entry *elm; 2801 int error; 2802 2803 error = 0; 2804 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2805 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2806 lockstate); 2807 if (error == -1) 2808 break; 2809 } 2810 return (error); 2811 } 2812 2813 /* 2814 * Prepare for, or clean after, relocating an object marked with 2815 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2816 * segments are remapped read-write. After relocations are done, the 2817 * segment's permissions are returned back to the modes specified in 2818 * the phdrs. If any relocation happened, or always for wired 2819 * program, COW is triggered. 2820 */ 2821 static int 2822 reloc_textrel_prot(Obj_Entry *obj, bool before) 2823 { 2824 const Elf_Phdr *ph; 2825 void *base; 2826 size_t l, sz; 2827 int prot; 2828 2829 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2830 l--, ph++) { 2831 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2832 continue; 2833 base = obj->relocbase + trunc_page(ph->p_vaddr); 2834 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2835 trunc_page(ph->p_vaddr); 2836 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2837 if (mprotect(base, sz, prot) == -1) { 2838 _rtld_error("%s: Cannot write-%sable text segment: %s", 2839 obj->path, before ? "en" : "dis", 2840 rtld_strerror(errno)); 2841 return (-1); 2842 } 2843 } 2844 return (0); 2845 } 2846 2847 /* 2848 * Relocate single object. 2849 * Returns 0 on success, or -1 on failure. 2850 */ 2851 static int 2852 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2853 int flags, RtldLockState *lockstate) 2854 { 2855 2856 if (obj->relocated) 2857 return (0); 2858 obj->relocated = true; 2859 if (obj != rtldobj) 2860 dbg("relocating \"%s\"", obj->path); 2861 2862 if (obj->symtab == NULL || obj->strtab == NULL || 2863 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2864 _rtld_error("%s: Shared object has no run-time symbol table", 2865 obj->path); 2866 return (-1); 2867 } 2868 2869 /* There are relocations to the write-protected text segment. */ 2870 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2871 return (-1); 2872 2873 /* Process the non-PLT non-IFUNC relocations. */ 2874 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2875 return (-1); 2876 2877 /* Re-protected the text segment. */ 2878 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2879 return (-1); 2880 2881 /* Set the special PLT or GOT entries. */ 2882 init_pltgot(obj); 2883 2884 /* Process the PLT relocations. */ 2885 if (reloc_plt(obj) == -1) 2886 return (-1); 2887 /* Relocate the jump slots if we are doing immediate binding. */ 2888 if (obj->bind_now || bind_now) 2889 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2890 return (-1); 2891 2892 /* 2893 * Process the non-PLT IFUNC relocations. The relocations are 2894 * processed in two phases, because IFUNC resolvers may 2895 * reference other symbols, which must be readily processed 2896 * before resolvers are called. 2897 */ 2898 if (obj->non_plt_gnu_ifunc && 2899 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2900 return (-1); 2901 2902 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2903 return (-1); 2904 2905 /* 2906 * Set up the magic number and version in the Obj_Entry. These 2907 * were checked in the crt1.o from the original ElfKit, so we 2908 * set them for backward compatibility. 2909 */ 2910 obj->magic = RTLD_MAGIC; 2911 obj->version = RTLD_VERSION; 2912 2913 return (0); 2914 } 2915 2916 /* 2917 * Relocate newly-loaded shared objects. The argument is a pointer to 2918 * the Obj_Entry for the first such object. All objects from the first 2919 * to the end of the list of objects are relocated. Returns 0 on success, 2920 * or -1 on failure. 2921 */ 2922 static int 2923 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2924 int flags, RtldLockState *lockstate) 2925 { 2926 Obj_Entry *obj; 2927 int error; 2928 2929 for (error = 0, obj = first; obj != NULL; 2930 obj = TAILQ_NEXT(obj, next)) { 2931 if (obj->marker) 2932 continue; 2933 error = relocate_object(obj, bind_now, rtldobj, flags, 2934 lockstate); 2935 if (error == -1) 2936 break; 2937 } 2938 return (error); 2939 } 2940 2941 /* 2942 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2943 * referencing STT_GNU_IFUNC symbols is postponed till the other 2944 * relocations are done. The indirect functions specified as 2945 * ifunc are allowed to call other symbols, so we need to have 2946 * objects relocated before asking for resolution from indirects. 2947 * 2948 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2949 * instead of the usual lazy handling of PLT slots. It is 2950 * consistent with how GNU does it. 2951 */ 2952 static int 2953 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2954 RtldLockState *lockstate) 2955 { 2956 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2957 return (-1); 2958 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2959 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2960 return (-1); 2961 return (0); 2962 } 2963 2964 static int 2965 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2966 RtldLockState *lockstate) 2967 { 2968 Obj_Entry *obj; 2969 2970 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2971 if (obj->marker) 2972 continue; 2973 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2974 return (-1); 2975 } 2976 return (0); 2977 } 2978 2979 static int 2980 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2981 RtldLockState *lockstate) 2982 { 2983 Objlist_Entry *elm; 2984 2985 STAILQ_FOREACH(elm, list, link) { 2986 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2987 lockstate) == -1) 2988 return (-1); 2989 } 2990 return (0); 2991 } 2992 2993 /* 2994 * Cleanup procedure. It will be called (by the atexit mechanism) just 2995 * before the process exits. 2996 */ 2997 static void 2998 rtld_exit(void) 2999 { 3000 RtldLockState lockstate; 3001 3002 wlock_acquire(rtld_bind_lock, &lockstate); 3003 dbg("rtld_exit()"); 3004 objlist_call_fini(&list_fini, NULL, &lockstate); 3005 /* No need to remove the items from the list, since we are exiting. */ 3006 if (!libmap_disable) 3007 lm_fini(); 3008 lock_release(rtld_bind_lock, &lockstate); 3009 } 3010 3011 /* 3012 * Iterate over a search path, translate each element, and invoke the 3013 * callback on the result. 3014 */ 3015 static void * 3016 path_enumerate(const char *path, path_enum_proc callback, 3017 const char *refobj_path, void *arg) 3018 { 3019 const char *trans; 3020 if (path == NULL) 3021 return (NULL); 3022 3023 path += strspn(path, ":;"); 3024 while (*path != '\0') { 3025 size_t len; 3026 char *res; 3027 3028 len = strcspn(path, ":;"); 3029 trans = lm_findn(refobj_path, path, len); 3030 if (trans) 3031 res = callback(trans, strlen(trans), arg); 3032 else 3033 res = callback(path, len, arg); 3034 3035 if (res != NULL) 3036 return (res); 3037 3038 path += len; 3039 path += strspn(path, ":;"); 3040 } 3041 3042 return (NULL); 3043 } 3044 3045 struct try_library_args { 3046 const char *name; 3047 size_t namelen; 3048 char *buffer; 3049 size_t buflen; 3050 int fd; 3051 }; 3052 3053 static void * 3054 try_library_path(const char *dir, size_t dirlen, void *param) 3055 { 3056 struct try_library_args *arg; 3057 int fd; 3058 3059 arg = param; 3060 if (*dir == '/' || trust) { 3061 char *pathname; 3062 3063 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3064 return (NULL); 3065 3066 pathname = arg->buffer; 3067 strncpy(pathname, dir, dirlen); 3068 pathname[dirlen] = '/'; 3069 strcpy(pathname + dirlen + 1, arg->name); 3070 3071 dbg(" Trying \"%s\"", pathname); 3072 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3073 if (fd >= 0) { 3074 dbg(" Opened \"%s\", fd %d", pathname, fd); 3075 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3076 strcpy(pathname, arg->buffer); 3077 arg->fd = fd; 3078 return (pathname); 3079 } else { 3080 dbg(" Failed to open \"%s\": %s", 3081 pathname, rtld_strerror(errno)); 3082 } 3083 } 3084 return (NULL); 3085 } 3086 3087 static char * 3088 search_library_path(const char *name, const char *path, 3089 const char *refobj_path, int *fdp) 3090 { 3091 char *p; 3092 struct try_library_args arg; 3093 3094 if (path == NULL) 3095 return NULL; 3096 3097 arg.name = name; 3098 arg.namelen = strlen(name); 3099 arg.buffer = xmalloc(PATH_MAX); 3100 arg.buflen = PATH_MAX; 3101 arg.fd = -1; 3102 3103 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3104 *fdp = arg.fd; 3105 3106 free(arg.buffer); 3107 3108 return (p); 3109 } 3110 3111 3112 /* 3113 * Finds the library with the given name using the directory descriptors 3114 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3115 * 3116 * Returns a freshly-opened close-on-exec file descriptor for the library, 3117 * or -1 if the library cannot be found. 3118 */ 3119 static char * 3120 search_library_pathfds(const char *name, const char *path, int *fdp) 3121 { 3122 char *envcopy, *fdstr, *found, *last_token; 3123 size_t len; 3124 int dirfd, fd; 3125 3126 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3127 3128 /* Don't load from user-specified libdirs into setuid binaries. */ 3129 if (!trust) 3130 return (NULL); 3131 3132 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3133 if (path == NULL) 3134 return (NULL); 3135 3136 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3137 if (name[0] == '/') { 3138 dbg("Absolute path (%s) passed to %s", name, __func__); 3139 return (NULL); 3140 } 3141 3142 /* 3143 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3144 * copy of the path, as strtok_r rewrites separator tokens 3145 * with '\0'. 3146 */ 3147 found = NULL; 3148 envcopy = xstrdup(path); 3149 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3150 fdstr = strtok_r(NULL, ":", &last_token)) { 3151 dirfd = parse_integer(fdstr); 3152 if (dirfd < 0) { 3153 _rtld_error("failed to parse directory FD: '%s'", 3154 fdstr); 3155 break; 3156 } 3157 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3158 if (fd >= 0) { 3159 *fdp = fd; 3160 len = strlen(fdstr) + strlen(name) + 3; 3161 found = xmalloc(len); 3162 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3163 _rtld_error("error generating '%d/%s'", 3164 dirfd, name); 3165 rtld_die(); 3166 } 3167 dbg("open('%s') => %d", found, fd); 3168 break; 3169 } 3170 } 3171 free(envcopy); 3172 3173 return (found); 3174 } 3175 3176 3177 int 3178 dlclose(void *handle) 3179 { 3180 RtldLockState lockstate; 3181 int error; 3182 3183 wlock_acquire(rtld_bind_lock, &lockstate); 3184 error = dlclose_locked(handle, &lockstate); 3185 lock_release(rtld_bind_lock, &lockstate); 3186 return (error); 3187 } 3188 3189 static int 3190 dlclose_locked(void *handle, RtldLockState *lockstate) 3191 { 3192 Obj_Entry *root; 3193 3194 root = dlcheck(handle); 3195 if (root == NULL) 3196 return -1; 3197 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3198 root->path); 3199 3200 /* Unreference the object and its dependencies. */ 3201 root->dl_refcount--; 3202 3203 if (root->refcount == 1) { 3204 /* 3205 * The object will be no longer referenced, so we must unload it. 3206 * First, call the fini functions. 3207 */ 3208 objlist_call_fini(&list_fini, root, lockstate); 3209 3210 unref_dag(root); 3211 3212 /* Finish cleaning up the newly-unreferenced objects. */ 3213 GDB_STATE(RT_DELETE,&root->linkmap); 3214 unload_object(root, lockstate); 3215 GDB_STATE(RT_CONSISTENT,NULL); 3216 } else 3217 unref_dag(root); 3218 3219 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3220 return 0; 3221 } 3222 3223 char * 3224 dlerror(void) 3225 { 3226 char *msg = error_message; 3227 error_message = NULL; 3228 return msg; 3229 } 3230 3231 /* 3232 * This function is deprecated and has no effect. 3233 */ 3234 void 3235 dllockinit(void *context, 3236 void *(*_lock_create)(void *context) __unused, 3237 void (*_rlock_acquire)(void *lock) __unused, 3238 void (*_wlock_acquire)(void *lock) __unused, 3239 void (*_lock_release)(void *lock) __unused, 3240 void (*_lock_destroy)(void *lock) __unused, 3241 void (*context_destroy)(void *context)) 3242 { 3243 static void *cur_context; 3244 static void (*cur_context_destroy)(void *); 3245 3246 /* Just destroy the context from the previous call, if necessary. */ 3247 if (cur_context_destroy != NULL) 3248 cur_context_destroy(cur_context); 3249 cur_context = context; 3250 cur_context_destroy = context_destroy; 3251 } 3252 3253 void * 3254 dlopen(const char *name, int mode) 3255 { 3256 3257 return (rtld_dlopen(name, -1, mode)); 3258 } 3259 3260 void * 3261 fdlopen(int fd, int mode) 3262 { 3263 3264 return (rtld_dlopen(NULL, fd, mode)); 3265 } 3266 3267 static void * 3268 rtld_dlopen(const char *name, int fd, int mode) 3269 { 3270 RtldLockState lockstate; 3271 int lo_flags; 3272 3273 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3274 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3275 if (ld_tracing != NULL) { 3276 rlock_acquire(rtld_bind_lock, &lockstate); 3277 if (sigsetjmp(lockstate.env, 0) != 0) 3278 lock_upgrade(rtld_bind_lock, &lockstate); 3279 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3280 lock_release(rtld_bind_lock, &lockstate); 3281 } 3282 lo_flags = RTLD_LO_DLOPEN; 3283 if (mode & RTLD_NODELETE) 3284 lo_flags |= RTLD_LO_NODELETE; 3285 if (mode & RTLD_NOLOAD) 3286 lo_flags |= RTLD_LO_NOLOAD; 3287 if (ld_tracing != NULL) 3288 lo_flags |= RTLD_LO_TRACE; 3289 3290 return (dlopen_object(name, fd, obj_main, lo_flags, 3291 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3292 } 3293 3294 static void 3295 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3296 { 3297 3298 obj->dl_refcount--; 3299 unref_dag(obj); 3300 if (obj->refcount == 0) 3301 unload_object(obj, lockstate); 3302 } 3303 3304 static Obj_Entry * 3305 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3306 int mode, RtldLockState *lockstate) 3307 { 3308 Obj_Entry *old_obj_tail; 3309 Obj_Entry *obj; 3310 Objlist initlist; 3311 RtldLockState mlockstate; 3312 int result; 3313 3314 objlist_init(&initlist); 3315 3316 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3317 wlock_acquire(rtld_bind_lock, &mlockstate); 3318 lockstate = &mlockstate; 3319 } 3320 GDB_STATE(RT_ADD,NULL); 3321 3322 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3323 obj = NULL; 3324 if (name == NULL && fd == -1) { 3325 obj = obj_main; 3326 obj->refcount++; 3327 } else { 3328 obj = load_object(name, fd, refobj, lo_flags); 3329 } 3330 3331 if (obj) { 3332 obj->dl_refcount++; 3333 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3334 objlist_push_tail(&list_global, obj); 3335 if (globallist_next(old_obj_tail) != NULL) { 3336 /* We loaded something new. */ 3337 assert(globallist_next(old_obj_tail) == obj); 3338 result = load_needed_objects(obj, 3339 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3340 init_dag(obj); 3341 ref_dag(obj); 3342 if (result != -1) 3343 result = rtld_verify_versions(&obj->dagmembers); 3344 if (result != -1 && ld_tracing) 3345 goto trace; 3346 if (result == -1 || relocate_object_dag(obj, 3347 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3348 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3349 lockstate) == -1) { 3350 dlopen_cleanup(obj, lockstate); 3351 obj = NULL; 3352 } else if (lo_flags & RTLD_LO_EARLY) { 3353 /* 3354 * Do not call the init functions for early loaded 3355 * filtees. The image is still not initialized enough 3356 * for them to work. 3357 * 3358 * Our object is found by the global object list and 3359 * will be ordered among all init calls done right 3360 * before transferring control to main. 3361 */ 3362 } else { 3363 /* Make list of init functions to call. */ 3364 initlist_add_objects(obj, obj, &initlist); 3365 } 3366 /* 3367 * Process all no_delete or global objects here, given 3368 * them own DAGs to prevent their dependencies from being 3369 * unloaded. This has to be done after we have loaded all 3370 * of the dependencies, so that we do not miss any. 3371 */ 3372 if (obj != NULL) 3373 process_z(obj); 3374 } else { 3375 /* 3376 * Bump the reference counts for objects on this DAG. If 3377 * this is the first dlopen() call for the object that was 3378 * already loaded as a dependency, initialize the dag 3379 * starting at it. 3380 */ 3381 init_dag(obj); 3382 ref_dag(obj); 3383 3384 if ((lo_flags & RTLD_LO_TRACE) != 0) 3385 goto trace; 3386 } 3387 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3388 obj->z_nodelete) && !obj->ref_nodel) { 3389 dbg("obj %s nodelete", obj->path); 3390 ref_dag(obj); 3391 obj->z_nodelete = obj->ref_nodel = true; 3392 } 3393 } 3394 3395 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3396 name); 3397 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3398 3399 if (!(lo_flags & RTLD_LO_EARLY)) { 3400 map_stacks_exec(lockstate); 3401 } 3402 3403 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3404 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3405 lockstate) == -1) { 3406 objlist_clear(&initlist); 3407 dlopen_cleanup(obj, lockstate); 3408 if (lockstate == &mlockstate) 3409 lock_release(rtld_bind_lock, lockstate); 3410 return (NULL); 3411 } 3412 3413 if (!(lo_flags & RTLD_LO_EARLY)) { 3414 /* Call the init functions. */ 3415 objlist_call_init(&initlist, lockstate); 3416 } 3417 objlist_clear(&initlist); 3418 if (lockstate == &mlockstate) 3419 lock_release(rtld_bind_lock, lockstate); 3420 return obj; 3421 trace: 3422 trace_loaded_objects(obj); 3423 if (lockstate == &mlockstate) 3424 lock_release(rtld_bind_lock, lockstate); 3425 exit(0); 3426 } 3427 3428 static void * 3429 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3430 int flags) 3431 { 3432 DoneList donelist; 3433 const Obj_Entry *obj, *defobj; 3434 const Elf_Sym *def; 3435 SymLook req; 3436 RtldLockState lockstate; 3437 tls_index ti; 3438 void *sym; 3439 int res; 3440 3441 def = NULL; 3442 defobj = NULL; 3443 symlook_init(&req, name); 3444 req.ventry = ve; 3445 req.flags = flags | SYMLOOK_IN_PLT; 3446 req.lockstate = &lockstate; 3447 3448 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3449 rlock_acquire(rtld_bind_lock, &lockstate); 3450 if (sigsetjmp(lockstate.env, 0) != 0) 3451 lock_upgrade(rtld_bind_lock, &lockstate); 3452 if (handle == NULL || handle == RTLD_NEXT || 3453 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3454 3455 if ((obj = obj_from_addr(retaddr)) == NULL) { 3456 _rtld_error("Cannot determine caller's shared object"); 3457 lock_release(rtld_bind_lock, &lockstate); 3458 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3459 return NULL; 3460 } 3461 if (handle == NULL) { /* Just the caller's shared object. */ 3462 res = symlook_obj(&req, obj); 3463 if (res == 0) { 3464 def = req.sym_out; 3465 defobj = req.defobj_out; 3466 } 3467 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3468 handle == RTLD_SELF) { /* ... caller included */ 3469 if (handle == RTLD_NEXT) 3470 obj = globallist_next(obj); 3471 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3472 if (obj->marker) 3473 continue; 3474 res = symlook_obj(&req, obj); 3475 if (res == 0) { 3476 if (def == NULL || 3477 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3478 def = req.sym_out; 3479 defobj = req.defobj_out; 3480 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3481 break; 3482 } 3483 } 3484 } 3485 /* 3486 * Search the dynamic linker itself, and possibly resolve the 3487 * symbol from there. This is how the application links to 3488 * dynamic linker services such as dlopen. 3489 */ 3490 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3491 res = symlook_obj(&req, &obj_rtld); 3492 if (res == 0) { 3493 def = req.sym_out; 3494 defobj = req.defobj_out; 3495 } 3496 } 3497 } else { 3498 assert(handle == RTLD_DEFAULT); 3499 res = symlook_default(&req, obj); 3500 if (res == 0) { 3501 defobj = req.defobj_out; 3502 def = req.sym_out; 3503 } 3504 } 3505 } else { 3506 if ((obj = dlcheck(handle)) == NULL) { 3507 lock_release(rtld_bind_lock, &lockstate); 3508 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3509 return NULL; 3510 } 3511 3512 donelist_init(&donelist); 3513 if (obj->mainprog) { 3514 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3515 res = symlook_global(&req, &donelist); 3516 if (res == 0) { 3517 def = req.sym_out; 3518 defobj = req.defobj_out; 3519 } 3520 /* 3521 * Search the dynamic linker itself, and possibly resolve the 3522 * symbol from there. This is how the application links to 3523 * dynamic linker services such as dlopen. 3524 */ 3525 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3526 res = symlook_obj(&req, &obj_rtld); 3527 if (res == 0) { 3528 def = req.sym_out; 3529 defobj = req.defobj_out; 3530 } 3531 } 3532 } 3533 else { 3534 /* Search the whole DAG rooted at the given object. */ 3535 res = symlook_list(&req, &obj->dagmembers, &donelist); 3536 if (res == 0) { 3537 def = req.sym_out; 3538 defobj = req.defobj_out; 3539 } 3540 } 3541 } 3542 3543 if (def != NULL) { 3544 lock_release(rtld_bind_lock, &lockstate); 3545 3546 /* 3547 * The value required by the caller is derived from the value 3548 * of the symbol. this is simply the relocated value of the 3549 * symbol. 3550 */ 3551 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3552 sym = make_function_pointer(def, defobj); 3553 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3554 sym = rtld_resolve_ifunc(defobj, def); 3555 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3556 ti.ti_module = defobj->tlsindex; 3557 ti.ti_offset = def->st_value; 3558 sym = __tls_get_addr(&ti); 3559 } else 3560 sym = defobj->relocbase + def->st_value; 3561 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3562 return (sym); 3563 } 3564 3565 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3566 ve != NULL ? ve->name : ""); 3567 lock_release(rtld_bind_lock, &lockstate); 3568 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3569 return NULL; 3570 } 3571 3572 void * 3573 dlsym(void *handle, const char *name) 3574 { 3575 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3576 SYMLOOK_DLSYM); 3577 } 3578 3579 dlfunc_t 3580 dlfunc(void *handle, const char *name) 3581 { 3582 union { 3583 void *d; 3584 dlfunc_t f; 3585 } rv; 3586 3587 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3588 SYMLOOK_DLSYM); 3589 return (rv.f); 3590 } 3591 3592 void * 3593 dlvsym(void *handle, const char *name, const char *version) 3594 { 3595 Ver_Entry ventry; 3596 3597 ventry.name = version; 3598 ventry.file = NULL; 3599 ventry.hash = elf_hash(version); 3600 ventry.flags= 0; 3601 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3602 SYMLOOK_DLSYM); 3603 } 3604 3605 int 3606 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3607 { 3608 const Obj_Entry *obj; 3609 RtldLockState lockstate; 3610 3611 rlock_acquire(rtld_bind_lock, &lockstate); 3612 obj = obj_from_addr(addr); 3613 if (obj == NULL) { 3614 _rtld_error("No shared object contains address"); 3615 lock_release(rtld_bind_lock, &lockstate); 3616 return (0); 3617 } 3618 rtld_fill_dl_phdr_info(obj, phdr_info); 3619 lock_release(rtld_bind_lock, &lockstate); 3620 return (1); 3621 } 3622 3623 int 3624 dladdr(const void *addr, Dl_info *info) 3625 { 3626 const Obj_Entry *obj; 3627 const Elf_Sym *def; 3628 void *symbol_addr; 3629 unsigned long symoffset; 3630 RtldLockState lockstate; 3631 3632 rlock_acquire(rtld_bind_lock, &lockstate); 3633 obj = obj_from_addr(addr); 3634 if (obj == NULL) { 3635 _rtld_error("No shared object contains address"); 3636 lock_release(rtld_bind_lock, &lockstate); 3637 return 0; 3638 } 3639 info->dli_fname = obj->path; 3640 info->dli_fbase = obj->mapbase; 3641 info->dli_saddr = (void *)0; 3642 info->dli_sname = NULL; 3643 3644 /* 3645 * Walk the symbol list looking for the symbol whose address is 3646 * closest to the address sent in. 3647 */ 3648 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3649 def = obj->symtab + symoffset; 3650 3651 /* 3652 * For skip the symbol if st_shndx is either SHN_UNDEF or 3653 * SHN_COMMON. 3654 */ 3655 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3656 continue; 3657 3658 /* 3659 * If the symbol is greater than the specified address, or if it 3660 * is further away from addr than the current nearest symbol, 3661 * then reject it. 3662 */ 3663 symbol_addr = obj->relocbase + def->st_value; 3664 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3665 continue; 3666 3667 /* Update our idea of the nearest symbol. */ 3668 info->dli_sname = obj->strtab + def->st_name; 3669 info->dli_saddr = symbol_addr; 3670 3671 /* Exact match? */ 3672 if (info->dli_saddr == addr) 3673 break; 3674 } 3675 lock_release(rtld_bind_lock, &lockstate); 3676 return 1; 3677 } 3678 3679 int 3680 dlinfo(void *handle, int request, void *p) 3681 { 3682 const Obj_Entry *obj; 3683 RtldLockState lockstate; 3684 int error; 3685 3686 rlock_acquire(rtld_bind_lock, &lockstate); 3687 3688 if (handle == NULL || handle == RTLD_SELF) { 3689 void *retaddr; 3690 3691 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3692 if ((obj = obj_from_addr(retaddr)) == NULL) 3693 _rtld_error("Cannot determine caller's shared object"); 3694 } else 3695 obj = dlcheck(handle); 3696 3697 if (obj == NULL) { 3698 lock_release(rtld_bind_lock, &lockstate); 3699 return (-1); 3700 } 3701 3702 error = 0; 3703 switch (request) { 3704 case RTLD_DI_LINKMAP: 3705 *((struct link_map const **)p) = &obj->linkmap; 3706 break; 3707 case RTLD_DI_ORIGIN: 3708 error = rtld_dirname(obj->path, p); 3709 break; 3710 3711 case RTLD_DI_SERINFOSIZE: 3712 case RTLD_DI_SERINFO: 3713 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3714 break; 3715 3716 default: 3717 _rtld_error("Invalid request %d passed to dlinfo()", request); 3718 error = -1; 3719 } 3720 3721 lock_release(rtld_bind_lock, &lockstate); 3722 3723 return (error); 3724 } 3725 3726 static void 3727 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3728 { 3729 3730 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3731 phdr_info->dlpi_name = obj->path; 3732 phdr_info->dlpi_phdr = obj->phdr; 3733 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3734 phdr_info->dlpi_tls_modid = obj->tlsindex; 3735 phdr_info->dlpi_tls_data = obj->tlsinit; 3736 phdr_info->dlpi_adds = obj_loads; 3737 phdr_info->dlpi_subs = obj_loads - obj_count; 3738 } 3739 3740 int 3741 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3742 { 3743 struct dl_phdr_info phdr_info; 3744 Obj_Entry *obj, marker; 3745 RtldLockState bind_lockstate, phdr_lockstate; 3746 int error; 3747 3748 init_marker(&marker); 3749 error = 0; 3750 3751 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3752 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3753 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3754 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3755 rtld_fill_dl_phdr_info(obj, &phdr_info); 3756 hold_object(obj); 3757 lock_release(rtld_bind_lock, &bind_lockstate); 3758 3759 error = callback(&phdr_info, sizeof phdr_info, param); 3760 3761 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3762 unhold_object(obj); 3763 obj = globallist_next(&marker); 3764 TAILQ_REMOVE(&obj_list, &marker, next); 3765 if (error != 0) { 3766 lock_release(rtld_bind_lock, &bind_lockstate); 3767 lock_release(rtld_phdr_lock, &phdr_lockstate); 3768 return (error); 3769 } 3770 } 3771 3772 if (error == 0) { 3773 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3774 lock_release(rtld_bind_lock, &bind_lockstate); 3775 error = callback(&phdr_info, sizeof(phdr_info), param); 3776 } 3777 lock_release(rtld_phdr_lock, &phdr_lockstate); 3778 return (error); 3779 } 3780 3781 static void * 3782 fill_search_info(const char *dir, size_t dirlen, void *param) 3783 { 3784 struct fill_search_info_args *arg; 3785 3786 arg = param; 3787 3788 if (arg->request == RTLD_DI_SERINFOSIZE) { 3789 arg->serinfo->dls_cnt ++; 3790 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3791 } else { 3792 struct dl_serpath *s_entry; 3793 3794 s_entry = arg->serpath; 3795 s_entry->dls_name = arg->strspace; 3796 s_entry->dls_flags = arg->flags; 3797 3798 strncpy(arg->strspace, dir, dirlen); 3799 arg->strspace[dirlen] = '\0'; 3800 3801 arg->strspace += dirlen + 1; 3802 arg->serpath++; 3803 } 3804 3805 return (NULL); 3806 } 3807 3808 static int 3809 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3810 { 3811 struct dl_serinfo _info; 3812 struct fill_search_info_args args; 3813 3814 args.request = RTLD_DI_SERINFOSIZE; 3815 args.serinfo = &_info; 3816 3817 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3818 _info.dls_cnt = 0; 3819 3820 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3821 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3822 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3823 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3824 if (!obj->z_nodeflib) 3825 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3826 3827 3828 if (request == RTLD_DI_SERINFOSIZE) { 3829 info->dls_size = _info.dls_size; 3830 info->dls_cnt = _info.dls_cnt; 3831 return (0); 3832 } 3833 3834 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3835 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3836 return (-1); 3837 } 3838 3839 args.request = RTLD_DI_SERINFO; 3840 args.serinfo = info; 3841 args.serpath = &info->dls_serpath[0]; 3842 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3843 3844 args.flags = LA_SER_RUNPATH; 3845 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3846 return (-1); 3847 3848 args.flags = LA_SER_LIBPATH; 3849 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3850 return (-1); 3851 3852 args.flags = LA_SER_RUNPATH; 3853 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3854 return (-1); 3855 3856 args.flags = LA_SER_CONFIG; 3857 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3858 != NULL) 3859 return (-1); 3860 3861 args.flags = LA_SER_DEFAULT; 3862 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3863 fill_search_info, NULL, &args) != NULL) 3864 return (-1); 3865 return (0); 3866 } 3867 3868 static int 3869 rtld_dirname(const char *path, char *bname) 3870 { 3871 const char *endp; 3872 3873 /* Empty or NULL string gets treated as "." */ 3874 if (path == NULL || *path == '\0') { 3875 bname[0] = '.'; 3876 bname[1] = '\0'; 3877 return (0); 3878 } 3879 3880 /* Strip trailing slashes */ 3881 endp = path + strlen(path) - 1; 3882 while (endp > path && *endp == '/') 3883 endp--; 3884 3885 /* Find the start of the dir */ 3886 while (endp > path && *endp != '/') 3887 endp--; 3888 3889 /* Either the dir is "/" or there are no slashes */ 3890 if (endp == path) { 3891 bname[0] = *endp == '/' ? '/' : '.'; 3892 bname[1] = '\0'; 3893 return (0); 3894 } else { 3895 do { 3896 endp--; 3897 } while (endp > path && *endp == '/'); 3898 } 3899 3900 if (endp - path + 2 > PATH_MAX) 3901 { 3902 _rtld_error("Filename is too long: %s", path); 3903 return(-1); 3904 } 3905 3906 strncpy(bname, path, endp - path + 1); 3907 bname[endp - path + 1] = '\0'; 3908 return (0); 3909 } 3910 3911 static int 3912 rtld_dirname_abs(const char *path, char *base) 3913 { 3914 char *last; 3915 3916 if (realpath(path, base) == NULL) 3917 return (-1); 3918 dbg("%s -> %s", path, base); 3919 last = strrchr(base, '/'); 3920 if (last == NULL) 3921 return (-1); 3922 if (last != base) 3923 *last = '\0'; 3924 return (0); 3925 } 3926 3927 static void 3928 linkmap_add(Obj_Entry *obj) 3929 { 3930 struct link_map *l = &obj->linkmap; 3931 struct link_map *prev; 3932 3933 obj->linkmap.l_name = obj->path; 3934 obj->linkmap.l_addr = obj->mapbase; 3935 obj->linkmap.l_ld = obj->dynamic; 3936 #ifdef __mips__ 3937 /* GDB needs load offset on MIPS to use the symbols */ 3938 obj->linkmap.l_offs = obj->relocbase; 3939 #endif 3940 3941 if (r_debug.r_map == NULL) { 3942 r_debug.r_map = l; 3943 return; 3944 } 3945 3946 /* 3947 * Scan to the end of the list, but not past the entry for the 3948 * dynamic linker, which we want to keep at the very end. 3949 */ 3950 for (prev = r_debug.r_map; 3951 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3952 prev = prev->l_next) 3953 ; 3954 3955 /* Link in the new entry. */ 3956 l->l_prev = prev; 3957 l->l_next = prev->l_next; 3958 if (l->l_next != NULL) 3959 l->l_next->l_prev = l; 3960 prev->l_next = l; 3961 } 3962 3963 static void 3964 linkmap_delete(Obj_Entry *obj) 3965 { 3966 struct link_map *l = &obj->linkmap; 3967 3968 if (l->l_prev == NULL) { 3969 if ((r_debug.r_map = l->l_next) != NULL) 3970 l->l_next->l_prev = NULL; 3971 return; 3972 } 3973 3974 if ((l->l_prev->l_next = l->l_next) != NULL) 3975 l->l_next->l_prev = l->l_prev; 3976 } 3977 3978 /* 3979 * Function for the debugger to set a breakpoint on to gain control. 3980 * 3981 * The two parameters allow the debugger to easily find and determine 3982 * what the runtime loader is doing and to whom it is doing it. 3983 * 3984 * When the loadhook trap is hit (r_debug_state, set at program 3985 * initialization), the arguments can be found on the stack: 3986 * 3987 * +8 struct link_map *m 3988 * +4 struct r_debug *rd 3989 * +0 RetAddr 3990 */ 3991 void 3992 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3993 { 3994 /* 3995 * The following is a hack to force the compiler to emit calls to 3996 * this function, even when optimizing. If the function is empty, 3997 * the compiler is not obliged to emit any code for calls to it, 3998 * even when marked __noinline. However, gdb depends on those 3999 * calls being made. 4000 */ 4001 __compiler_membar(); 4002 } 4003 4004 /* 4005 * A function called after init routines have completed. This can be used to 4006 * break before a program's entry routine is called, and can be used when 4007 * main is not available in the symbol table. 4008 */ 4009 void 4010 _r_debug_postinit(struct link_map *m __unused) 4011 { 4012 4013 /* See r_debug_state(). */ 4014 __compiler_membar(); 4015 } 4016 4017 static void 4018 release_object(Obj_Entry *obj) 4019 { 4020 4021 if (obj->holdcount > 0) { 4022 obj->unholdfree = true; 4023 return; 4024 } 4025 munmap(obj->mapbase, obj->mapsize); 4026 linkmap_delete(obj); 4027 obj_free(obj); 4028 } 4029 4030 /* 4031 * Get address of the pointer variable in the main program. 4032 * Prefer non-weak symbol over the weak one. 4033 */ 4034 static const void ** 4035 get_program_var_addr(const char *name, RtldLockState *lockstate) 4036 { 4037 SymLook req; 4038 DoneList donelist; 4039 4040 symlook_init(&req, name); 4041 req.lockstate = lockstate; 4042 donelist_init(&donelist); 4043 if (symlook_global(&req, &donelist) != 0) 4044 return (NULL); 4045 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4046 return ((const void **)make_function_pointer(req.sym_out, 4047 req.defobj_out)); 4048 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4049 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4050 else 4051 return ((const void **)(req.defobj_out->relocbase + 4052 req.sym_out->st_value)); 4053 } 4054 4055 /* 4056 * Set a pointer variable in the main program to the given value. This 4057 * is used to set key variables such as "environ" before any of the 4058 * init functions are called. 4059 */ 4060 static void 4061 set_program_var(const char *name, const void *value) 4062 { 4063 const void **addr; 4064 4065 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4066 dbg("\"%s\": *%p <-- %p", name, addr, value); 4067 *addr = value; 4068 } 4069 } 4070 4071 /* 4072 * Search the global objects, including dependencies and main object, 4073 * for the given symbol. 4074 */ 4075 static int 4076 symlook_global(SymLook *req, DoneList *donelist) 4077 { 4078 SymLook req1; 4079 const Objlist_Entry *elm; 4080 int res; 4081 4082 symlook_init_from_req(&req1, req); 4083 4084 /* Search all objects loaded at program start up. */ 4085 if (req->defobj_out == NULL || 4086 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4087 res = symlook_list(&req1, &list_main, donelist); 4088 if (res == 0 && (req->defobj_out == NULL || 4089 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4090 req->sym_out = req1.sym_out; 4091 req->defobj_out = req1.defobj_out; 4092 assert(req->defobj_out != NULL); 4093 } 4094 } 4095 4096 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4097 STAILQ_FOREACH(elm, &list_global, link) { 4098 if (req->defobj_out != NULL && 4099 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4100 break; 4101 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4102 if (res == 0 && (req->defobj_out == NULL || 4103 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4104 req->sym_out = req1.sym_out; 4105 req->defobj_out = req1.defobj_out; 4106 assert(req->defobj_out != NULL); 4107 } 4108 } 4109 4110 return (req->sym_out != NULL ? 0 : ESRCH); 4111 } 4112 4113 /* 4114 * Given a symbol name in a referencing object, find the corresponding 4115 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4116 * no definition was found. Returns a pointer to the Obj_Entry of the 4117 * defining object via the reference parameter DEFOBJ_OUT. 4118 */ 4119 static int 4120 symlook_default(SymLook *req, const Obj_Entry *refobj) 4121 { 4122 DoneList donelist; 4123 const Objlist_Entry *elm; 4124 SymLook req1; 4125 int res; 4126 4127 donelist_init(&donelist); 4128 symlook_init_from_req(&req1, req); 4129 4130 /* 4131 * Look first in the referencing object if linked symbolically, 4132 * and similarly handle protected symbols. 4133 */ 4134 res = symlook_obj(&req1, refobj); 4135 if (res == 0 && (refobj->symbolic || 4136 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4137 req->sym_out = req1.sym_out; 4138 req->defobj_out = req1.defobj_out; 4139 assert(req->defobj_out != NULL); 4140 } 4141 if (refobj->symbolic || req->defobj_out != NULL) 4142 donelist_check(&donelist, refobj); 4143 4144 symlook_global(req, &donelist); 4145 4146 /* Search all dlopened DAGs containing the referencing object. */ 4147 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4148 if (req->sym_out != NULL && 4149 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4150 break; 4151 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4152 if (res == 0 && (req->sym_out == NULL || 4153 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4154 req->sym_out = req1.sym_out; 4155 req->defobj_out = req1.defobj_out; 4156 assert(req->defobj_out != NULL); 4157 } 4158 } 4159 4160 /* 4161 * Search the dynamic linker itself, and possibly resolve the 4162 * symbol from there. This is how the application links to 4163 * dynamic linker services such as dlopen. 4164 */ 4165 if (req->sym_out == NULL || 4166 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4167 res = symlook_obj(&req1, &obj_rtld); 4168 if (res == 0) { 4169 req->sym_out = req1.sym_out; 4170 req->defobj_out = req1.defobj_out; 4171 assert(req->defobj_out != NULL); 4172 } 4173 } 4174 4175 return (req->sym_out != NULL ? 0 : ESRCH); 4176 } 4177 4178 static int 4179 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4180 { 4181 const Elf_Sym *def; 4182 const Obj_Entry *defobj; 4183 const Objlist_Entry *elm; 4184 SymLook req1; 4185 int res; 4186 4187 def = NULL; 4188 defobj = NULL; 4189 STAILQ_FOREACH(elm, objlist, link) { 4190 if (donelist_check(dlp, elm->obj)) 4191 continue; 4192 symlook_init_from_req(&req1, req); 4193 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4194 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4195 def = req1.sym_out; 4196 defobj = req1.defobj_out; 4197 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4198 break; 4199 } 4200 } 4201 } 4202 if (def != NULL) { 4203 req->sym_out = def; 4204 req->defobj_out = defobj; 4205 return (0); 4206 } 4207 return (ESRCH); 4208 } 4209 4210 /* 4211 * Search the chain of DAGS cointed to by the given Needed_Entry 4212 * for a symbol of the given name. Each DAG is scanned completely 4213 * before advancing to the next one. Returns a pointer to the symbol, 4214 * or NULL if no definition was found. 4215 */ 4216 static int 4217 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4218 { 4219 const Elf_Sym *def; 4220 const Needed_Entry *n; 4221 const Obj_Entry *defobj; 4222 SymLook req1; 4223 int res; 4224 4225 def = NULL; 4226 defobj = NULL; 4227 symlook_init_from_req(&req1, req); 4228 for (n = needed; n != NULL; n = n->next) { 4229 if (n->obj == NULL || 4230 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4231 continue; 4232 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4233 def = req1.sym_out; 4234 defobj = req1.defobj_out; 4235 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4236 break; 4237 } 4238 } 4239 if (def != NULL) { 4240 req->sym_out = def; 4241 req->defobj_out = defobj; 4242 return (0); 4243 } 4244 return (ESRCH); 4245 } 4246 4247 /* 4248 * Search the symbol table of a single shared object for a symbol of 4249 * the given name and version, if requested. Returns a pointer to the 4250 * symbol, or NULL if no definition was found. If the object is 4251 * filter, return filtered symbol from filtee. 4252 * 4253 * The symbol's hash value is passed in for efficiency reasons; that 4254 * eliminates many recomputations of the hash value. 4255 */ 4256 int 4257 symlook_obj(SymLook *req, const Obj_Entry *obj) 4258 { 4259 DoneList donelist; 4260 SymLook req1; 4261 int flags, res, mres; 4262 4263 /* 4264 * If there is at least one valid hash at this point, we prefer to 4265 * use the faster GNU version if available. 4266 */ 4267 if (obj->valid_hash_gnu) 4268 mres = symlook_obj1_gnu(req, obj); 4269 else if (obj->valid_hash_sysv) 4270 mres = symlook_obj1_sysv(req, obj); 4271 else 4272 return (EINVAL); 4273 4274 if (mres == 0) { 4275 if (obj->needed_filtees != NULL) { 4276 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4277 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4278 donelist_init(&donelist); 4279 symlook_init_from_req(&req1, req); 4280 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4281 if (res == 0) { 4282 req->sym_out = req1.sym_out; 4283 req->defobj_out = req1.defobj_out; 4284 } 4285 return (res); 4286 } 4287 if (obj->needed_aux_filtees != NULL) { 4288 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4289 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4290 donelist_init(&donelist); 4291 symlook_init_from_req(&req1, req); 4292 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4293 if (res == 0) { 4294 req->sym_out = req1.sym_out; 4295 req->defobj_out = req1.defobj_out; 4296 return (res); 4297 } 4298 } 4299 } 4300 return (mres); 4301 } 4302 4303 /* Symbol match routine common to both hash functions */ 4304 static bool 4305 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4306 const unsigned long symnum) 4307 { 4308 Elf_Versym verndx; 4309 const Elf_Sym *symp; 4310 const char *strp; 4311 4312 symp = obj->symtab + symnum; 4313 strp = obj->strtab + symp->st_name; 4314 4315 switch (ELF_ST_TYPE(symp->st_info)) { 4316 case STT_FUNC: 4317 case STT_NOTYPE: 4318 case STT_OBJECT: 4319 case STT_COMMON: 4320 case STT_GNU_IFUNC: 4321 if (symp->st_value == 0) 4322 return (false); 4323 /* fallthrough */ 4324 case STT_TLS: 4325 if (symp->st_shndx != SHN_UNDEF) 4326 break; 4327 #ifndef __mips__ 4328 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4329 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4330 break; 4331 #endif 4332 /* fallthrough */ 4333 default: 4334 return (false); 4335 } 4336 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4337 return (false); 4338 4339 if (req->ventry == NULL) { 4340 if (obj->versyms != NULL) { 4341 verndx = VER_NDX(obj->versyms[symnum]); 4342 if (verndx > obj->vernum) { 4343 _rtld_error( 4344 "%s: symbol %s references wrong version %d", 4345 obj->path, obj->strtab + symnum, verndx); 4346 return (false); 4347 } 4348 /* 4349 * If we are not called from dlsym (i.e. this 4350 * is a normal relocation from unversioned 4351 * binary), accept the symbol immediately if 4352 * it happens to have first version after this 4353 * shared object became versioned. Otherwise, 4354 * if symbol is versioned and not hidden, 4355 * remember it. If it is the only symbol with 4356 * this name exported by the shared object, it 4357 * will be returned as a match by the calling 4358 * function. If symbol is global (verndx < 2) 4359 * accept it unconditionally. 4360 */ 4361 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4362 verndx == VER_NDX_GIVEN) { 4363 result->sym_out = symp; 4364 return (true); 4365 } 4366 else if (verndx >= VER_NDX_GIVEN) { 4367 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4368 == 0) { 4369 if (result->vsymp == NULL) 4370 result->vsymp = symp; 4371 result->vcount++; 4372 } 4373 return (false); 4374 } 4375 } 4376 result->sym_out = symp; 4377 return (true); 4378 } 4379 if (obj->versyms == NULL) { 4380 if (object_match_name(obj, req->ventry->name)) { 4381 _rtld_error("%s: object %s should provide version %s " 4382 "for symbol %s", obj_rtld.path, obj->path, 4383 req->ventry->name, obj->strtab + symnum); 4384 return (false); 4385 } 4386 } else { 4387 verndx = VER_NDX(obj->versyms[symnum]); 4388 if (verndx > obj->vernum) { 4389 _rtld_error("%s: symbol %s references wrong version %d", 4390 obj->path, obj->strtab + symnum, verndx); 4391 return (false); 4392 } 4393 if (obj->vertab[verndx].hash != req->ventry->hash || 4394 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4395 /* 4396 * Version does not match. Look if this is a 4397 * global symbol and if it is not hidden. If 4398 * global symbol (verndx < 2) is available, 4399 * use it. Do not return symbol if we are 4400 * called by dlvsym, because dlvsym looks for 4401 * a specific version and default one is not 4402 * what dlvsym wants. 4403 */ 4404 if ((req->flags & SYMLOOK_DLSYM) || 4405 (verndx >= VER_NDX_GIVEN) || 4406 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4407 return (false); 4408 } 4409 } 4410 result->sym_out = symp; 4411 return (true); 4412 } 4413 4414 /* 4415 * Search for symbol using SysV hash function. 4416 * obj->buckets is known not to be NULL at this point; the test for this was 4417 * performed with the obj->valid_hash_sysv assignment. 4418 */ 4419 static int 4420 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4421 { 4422 unsigned long symnum; 4423 Sym_Match_Result matchres; 4424 4425 matchres.sym_out = NULL; 4426 matchres.vsymp = NULL; 4427 matchres.vcount = 0; 4428 4429 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4430 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4431 if (symnum >= obj->nchains) 4432 return (ESRCH); /* Bad object */ 4433 4434 if (matched_symbol(req, obj, &matchres, symnum)) { 4435 req->sym_out = matchres.sym_out; 4436 req->defobj_out = obj; 4437 return (0); 4438 } 4439 } 4440 if (matchres.vcount == 1) { 4441 req->sym_out = matchres.vsymp; 4442 req->defobj_out = obj; 4443 return (0); 4444 } 4445 return (ESRCH); 4446 } 4447 4448 /* Search for symbol using GNU hash function */ 4449 static int 4450 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4451 { 4452 Elf_Addr bloom_word; 4453 const Elf32_Word *hashval; 4454 Elf32_Word bucket; 4455 Sym_Match_Result matchres; 4456 unsigned int h1, h2; 4457 unsigned long symnum; 4458 4459 matchres.sym_out = NULL; 4460 matchres.vsymp = NULL; 4461 matchres.vcount = 0; 4462 4463 /* Pick right bitmask word from Bloom filter array */ 4464 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4465 obj->maskwords_bm_gnu]; 4466 4467 /* Calculate modulus word size of gnu hash and its derivative */ 4468 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4469 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4470 4471 /* Filter out the "definitely not in set" queries */ 4472 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4473 return (ESRCH); 4474 4475 /* Locate hash chain and corresponding value element*/ 4476 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4477 if (bucket == 0) 4478 return (ESRCH); 4479 hashval = &obj->chain_zero_gnu[bucket]; 4480 do { 4481 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4482 symnum = hashval - obj->chain_zero_gnu; 4483 if (matched_symbol(req, obj, &matchres, symnum)) { 4484 req->sym_out = matchres.sym_out; 4485 req->defobj_out = obj; 4486 return (0); 4487 } 4488 } 4489 } while ((*hashval++ & 1) == 0); 4490 if (matchres.vcount == 1) { 4491 req->sym_out = matchres.vsymp; 4492 req->defobj_out = obj; 4493 return (0); 4494 } 4495 return (ESRCH); 4496 } 4497 4498 static void 4499 trace_loaded_objects(Obj_Entry *obj) 4500 { 4501 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4502 int c; 4503 4504 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4505 main_local = ""; 4506 4507 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4508 fmt1 = "\t%o => %p (%x)\n"; 4509 4510 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4511 fmt2 = "\t%o (%x)\n"; 4512 4513 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4514 4515 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4516 Needed_Entry *needed; 4517 const char *name, *path; 4518 bool is_lib; 4519 4520 if (obj->marker) 4521 continue; 4522 if (list_containers && obj->needed != NULL) 4523 rtld_printf("%s:\n", obj->path); 4524 for (needed = obj->needed; needed; needed = needed->next) { 4525 if (needed->obj != NULL) { 4526 if (needed->obj->traced && !list_containers) 4527 continue; 4528 needed->obj->traced = true; 4529 path = needed->obj->path; 4530 } else 4531 path = "not found"; 4532 4533 name = obj->strtab + needed->name; 4534 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4535 4536 fmt = is_lib ? fmt1 : fmt2; 4537 while ((c = *fmt++) != '\0') { 4538 switch (c) { 4539 default: 4540 rtld_putchar(c); 4541 continue; 4542 case '\\': 4543 switch (c = *fmt) { 4544 case '\0': 4545 continue; 4546 case 'n': 4547 rtld_putchar('\n'); 4548 break; 4549 case 't': 4550 rtld_putchar('\t'); 4551 break; 4552 } 4553 break; 4554 case '%': 4555 switch (c = *fmt) { 4556 case '\0': 4557 continue; 4558 case '%': 4559 default: 4560 rtld_putchar(c); 4561 break; 4562 case 'A': 4563 rtld_putstr(main_local); 4564 break; 4565 case 'a': 4566 rtld_putstr(obj_main->path); 4567 break; 4568 case 'o': 4569 rtld_putstr(name); 4570 break; 4571 #if 0 4572 case 'm': 4573 rtld_printf("%d", sodp->sod_major); 4574 break; 4575 case 'n': 4576 rtld_printf("%d", sodp->sod_minor); 4577 break; 4578 #endif 4579 case 'p': 4580 rtld_putstr(path); 4581 break; 4582 case 'x': 4583 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4584 0); 4585 break; 4586 } 4587 break; 4588 } 4589 ++fmt; 4590 } 4591 } 4592 } 4593 } 4594 4595 /* 4596 * Unload a dlopened object and its dependencies from memory and from 4597 * our data structures. It is assumed that the DAG rooted in the 4598 * object has already been unreferenced, and that the object has a 4599 * reference count of 0. 4600 */ 4601 static void 4602 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4603 { 4604 Obj_Entry marker, *obj, *next; 4605 4606 assert(root->refcount == 0); 4607 4608 /* 4609 * Pass over the DAG removing unreferenced objects from 4610 * appropriate lists. 4611 */ 4612 unlink_object(root); 4613 4614 /* Unmap all objects that are no longer referenced. */ 4615 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4616 next = TAILQ_NEXT(obj, next); 4617 if (obj->marker || obj->refcount != 0) 4618 continue; 4619 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4620 obj->mapsize, 0, obj->path); 4621 dbg("unloading \"%s\"", obj->path); 4622 /* 4623 * Unlink the object now to prevent new references from 4624 * being acquired while the bind lock is dropped in 4625 * recursive dlclose() invocations. 4626 */ 4627 TAILQ_REMOVE(&obj_list, obj, next); 4628 obj_count--; 4629 4630 if (obj->filtees_loaded) { 4631 if (next != NULL) { 4632 init_marker(&marker); 4633 TAILQ_INSERT_BEFORE(next, &marker, next); 4634 unload_filtees(obj, lockstate); 4635 next = TAILQ_NEXT(&marker, next); 4636 TAILQ_REMOVE(&obj_list, &marker, next); 4637 } else 4638 unload_filtees(obj, lockstate); 4639 } 4640 release_object(obj); 4641 } 4642 } 4643 4644 static void 4645 unlink_object(Obj_Entry *root) 4646 { 4647 Objlist_Entry *elm; 4648 4649 if (root->refcount == 0) { 4650 /* Remove the object from the RTLD_GLOBAL list. */ 4651 objlist_remove(&list_global, root); 4652 4653 /* Remove the object from all objects' DAG lists. */ 4654 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4655 objlist_remove(&elm->obj->dldags, root); 4656 if (elm->obj != root) 4657 unlink_object(elm->obj); 4658 } 4659 } 4660 } 4661 4662 static void 4663 ref_dag(Obj_Entry *root) 4664 { 4665 Objlist_Entry *elm; 4666 4667 assert(root->dag_inited); 4668 STAILQ_FOREACH(elm, &root->dagmembers, link) 4669 elm->obj->refcount++; 4670 } 4671 4672 static void 4673 unref_dag(Obj_Entry *root) 4674 { 4675 Objlist_Entry *elm; 4676 4677 assert(root->dag_inited); 4678 STAILQ_FOREACH(elm, &root->dagmembers, link) 4679 elm->obj->refcount--; 4680 } 4681 4682 /* 4683 * Common code for MD __tls_get_addr(). 4684 */ 4685 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4686 static void * 4687 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4688 { 4689 Elf_Addr *newdtv, *dtv; 4690 RtldLockState lockstate; 4691 int to_copy; 4692 4693 dtv = *dtvp; 4694 /* Check dtv generation in case new modules have arrived */ 4695 if (dtv[0] != tls_dtv_generation) { 4696 wlock_acquire(rtld_bind_lock, &lockstate); 4697 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4698 to_copy = dtv[1]; 4699 if (to_copy > tls_max_index) 4700 to_copy = tls_max_index; 4701 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4702 newdtv[0] = tls_dtv_generation; 4703 newdtv[1] = tls_max_index; 4704 free(dtv); 4705 lock_release(rtld_bind_lock, &lockstate); 4706 dtv = *dtvp = newdtv; 4707 } 4708 4709 /* Dynamically allocate module TLS if necessary */ 4710 if (dtv[index + 1] == 0) { 4711 /* Signal safe, wlock will block out signals. */ 4712 wlock_acquire(rtld_bind_lock, &lockstate); 4713 if (!dtv[index + 1]) 4714 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4715 lock_release(rtld_bind_lock, &lockstate); 4716 } 4717 return ((void *)(dtv[index + 1] + offset)); 4718 } 4719 4720 void * 4721 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4722 { 4723 Elf_Addr *dtv; 4724 4725 dtv = *dtvp; 4726 /* Check dtv generation in case new modules have arrived */ 4727 if (__predict_true(dtv[0] == tls_dtv_generation && 4728 dtv[index + 1] != 0)) 4729 return ((void *)(dtv[index + 1] + offset)); 4730 return (tls_get_addr_slow(dtvp, index, offset)); 4731 } 4732 4733 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4734 defined(__powerpc__) || defined(__riscv) 4735 4736 /* 4737 * Return pointer to allocated TLS block 4738 */ 4739 static void * 4740 get_tls_block_ptr(void *tcb, size_t tcbsize) 4741 { 4742 size_t extra_size, post_size, pre_size, tls_block_size; 4743 size_t tls_init_align; 4744 4745 tls_init_align = MAX(obj_main->tlsalign, 1); 4746 4747 /* Compute fragments sizes. */ 4748 extra_size = tcbsize - TLS_TCB_SIZE; 4749 post_size = calculate_tls_post_size(tls_init_align); 4750 tls_block_size = tcbsize + post_size; 4751 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4752 4753 return ((char *)tcb - pre_size - extra_size); 4754 } 4755 4756 /* 4757 * Allocate Static TLS using the Variant I method. 4758 * 4759 * For details on the layout, see lib/libc/gen/tls.c. 4760 * 4761 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4762 * it is based on tls_last_offset, and TLS offsets here are really TCB 4763 * offsets, whereas libc's tls_static_space is just the executable's static 4764 * TLS segment. 4765 */ 4766 void * 4767 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4768 { 4769 Obj_Entry *obj; 4770 char *tls_block; 4771 Elf_Addr *dtv, **tcb; 4772 Elf_Addr addr; 4773 Elf_Addr i; 4774 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4775 size_t tls_init_align; 4776 4777 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4778 return (oldtcb); 4779 4780 assert(tcbsize >= TLS_TCB_SIZE); 4781 maxalign = MAX(tcbalign, tls_static_max_align); 4782 tls_init_align = MAX(obj_main->tlsalign, 1); 4783 4784 /* Compute fragmets sizes. */ 4785 extra_size = tcbsize - TLS_TCB_SIZE; 4786 post_size = calculate_tls_post_size(tls_init_align); 4787 tls_block_size = tcbsize + post_size; 4788 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4789 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4790 4791 /* Allocate whole TLS block */ 4792 tls_block = malloc_aligned(tls_block_size, maxalign); 4793 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4794 4795 if (oldtcb != NULL) { 4796 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4797 tls_static_space); 4798 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4799 4800 /* Adjust the DTV. */ 4801 dtv = tcb[0]; 4802 for (i = 0; i < dtv[1]; i++) { 4803 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4804 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4805 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4806 } 4807 } 4808 } else { 4809 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4810 tcb[0] = dtv; 4811 dtv[0] = tls_dtv_generation; 4812 dtv[1] = tls_max_index; 4813 4814 for (obj = globallist_curr(objs); obj != NULL; 4815 obj = globallist_next(obj)) { 4816 if (obj->tlsoffset > 0) { 4817 addr = (Elf_Addr)tcb + obj->tlsoffset; 4818 if (obj->tlsinitsize > 0) 4819 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4820 if (obj->tlssize > obj->tlsinitsize) 4821 memset((void*)(addr + obj->tlsinitsize), 0, 4822 obj->tlssize - obj->tlsinitsize); 4823 dtv[obj->tlsindex + 1] = addr; 4824 } 4825 } 4826 } 4827 4828 return (tcb); 4829 } 4830 4831 void 4832 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4833 { 4834 Elf_Addr *dtv; 4835 Elf_Addr tlsstart, tlsend; 4836 size_t post_size; 4837 size_t dtvsize, i, tls_init_align; 4838 4839 assert(tcbsize >= TLS_TCB_SIZE); 4840 tls_init_align = MAX(obj_main->tlsalign, 1); 4841 4842 /* Compute fragments sizes. */ 4843 post_size = calculate_tls_post_size(tls_init_align); 4844 4845 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4846 tlsend = (Elf_Addr)tcb + tls_static_space; 4847 4848 dtv = *(Elf_Addr **)tcb; 4849 dtvsize = dtv[1]; 4850 for (i = 0; i < dtvsize; i++) { 4851 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4852 free((void*)dtv[i+2]); 4853 } 4854 } 4855 free(dtv); 4856 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4857 } 4858 4859 #endif 4860 4861 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4862 4863 /* 4864 * Allocate Static TLS using the Variant II method. 4865 */ 4866 void * 4867 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4868 { 4869 Obj_Entry *obj; 4870 size_t size, ralign; 4871 char *tls; 4872 Elf_Addr *dtv, *olddtv; 4873 Elf_Addr segbase, oldsegbase, addr; 4874 size_t i; 4875 4876 ralign = tcbalign; 4877 if (tls_static_max_align > ralign) 4878 ralign = tls_static_max_align; 4879 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4880 4881 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4882 tls = malloc_aligned(size, ralign); 4883 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4884 4885 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4886 ((Elf_Addr*)segbase)[0] = segbase; 4887 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4888 4889 dtv[0] = tls_dtv_generation; 4890 dtv[1] = tls_max_index; 4891 4892 if (oldtls) { 4893 /* 4894 * Copy the static TLS block over whole. 4895 */ 4896 oldsegbase = (Elf_Addr) oldtls; 4897 memcpy((void *)(segbase - tls_static_space), 4898 (const void *)(oldsegbase - tls_static_space), 4899 tls_static_space); 4900 4901 /* 4902 * If any dynamic TLS blocks have been created tls_get_addr(), 4903 * move them over. 4904 */ 4905 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4906 for (i = 0; i < olddtv[1]; i++) { 4907 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4908 dtv[i+2] = olddtv[i+2]; 4909 olddtv[i+2] = 0; 4910 } 4911 } 4912 4913 /* 4914 * We assume that this block was the one we created with 4915 * allocate_initial_tls(). 4916 */ 4917 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4918 } else { 4919 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4920 if (obj->marker || obj->tlsoffset == 0) 4921 continue; 4922 addr = segbase - obj->tlsoffset; 4923 memset((void*)(addr + obj->tlsinitsize), 4924 0, obj->tlssize - obj->tlsinitsize); 4925 if (obj->tlsinit) 4926 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4927 dtv[obj->tlsindex + 1] = addr; 4928 } 4929 } 4930 4931 return (void*) segbase; 4932 } 4933 4934 void 4935 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4936 { 4937 Elf_Addr* dtv; 4938 size_t size, ralign; 4939 int dtvsize, i; 4940 Elf_Addr tlsstart, tlsend; 4941 4942 /* 4943 * Figure out the size of the initial TLS block so that we can 4944 * find stuff which ___tls_get_addr() allocated dynamically. 4945 */ 4946 ralign = tcbalign; 4947 if (tls_static_max_align > ralign) 4948 ralign = tls_static_max_align; 4949 size = round(tls_static_space, ralign); 4950 4951 dtv = ((Elf_Addr**)tls)[1]; 4952 dtvsize = dtv[1]; 4953 tlsend = (Elf_Addr) tls; 4954 tlsstart = tlsend - size; 4955 for (i = 0; i < dtvsize; i++) { 4956 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4957 free_aligned((void *)dtv[i + 2]); 4958 } 4959 } 4960 4961 free_aligned((void *)tlsstart); 4962 free((void*) dtv); 4963 } 4964 4965 #endif 4966 4967 /* 4968 * Allocate TLS block for module with given index. 4969 */ 4970 void * 4971 allocate_module_tls(int index) 4972 { 4973 Obj_Entry* obj; 4974 char* p; 4975 4976 TAILQ_FOREACH(obj, &obj_list, next) { 4977 if (obj->marker) 4978 continue; 4979 if (obj->tlsindex == index) 4980 break; 4981 } 4982 if (!obj) { 4983 _rtld_error("Can't find module with TLS index %d", index); 4984 rtld_die(); 4985 } 4986 4987 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4988 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4989 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4990 4991 return p; 4992 } 4993 4994 bool 4995 allocate_tls_offset(Obj_Entry *obj) 4996 { 4997 size_t off; 4998 4999 if (obj->tls_done) 5000 return true; 5001 5002 if (obj->tlssize == 0) { 5003 obj->tls_done = true; 5004 return true; 5005 } 5006 5007 if (tls_last_offset == 0) 5008 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5009 else 5010 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5011 obj->tlssize, obj->tlsalign); 5012 5013 /* 5014 * If we have already fixed the size of the static TLS block, we 5015 * must stay within that size. When allocating the static TLS, we 5016 * leave a small amount of space spare to be used for dynamically 5017 * loading modules which use static TLS. 5018 */ 5019 if (tls_static_space != 0) { 5020 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5021 return false; 5022 } else if (obj->tlsalign > tls_static_max_align) { 5023 tls_static_max_align = obj->tlsalign; 5024 } 5025 5026 tls_last_offset = obj->tlsoffset = off; 5027 tls_last_size = obj->tlssize; 5028 obj->tls_done = true; 5029 5030 return true; 5031 } 5032 5033 void 5034 free_tls_offset(Obj_Entry *obj) 5035 { 5036 5037 /* 5038 * If we were the last thing to allocate out of the static TLS 5039 * block, we give our space back to the 'allocator'. This is a 5040 * simplistic workaround to allow libGL.so.1 to be loaded and 5041 * unloaded multiple times. 5042 */ 5043 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5044 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5045 tls_last_offset -= obj->tlssize; 5046 tls_last_size = 0; 5047 } 5048 } 5049 5050 void * 5051 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5052 { 5053 void *ret; 5054 RtldLockState lockstate; 5055 5056 wlock_acquire(rtld_bind_lock, &lockstate); 5057 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5058 tcbsize, tcbalign); 5059 lock_release(rtld_bind_lock, &lockstate); 5060 return (ret); 5061 } 5062 5063 void 5064 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5065 { 5066 RtldLockState lockstate; 5067 5068 wlock_acquire(rtld_bind_lock, &lockstate); 5069 free_tls(tcb, tcbsize, tcbalign); 5070 lock_release(rtld_bind_lock, &lockstate); 5071 } 5072 5073 static void 5074 object_add_name(Obj_Entry *obj, const char *name) 5075 { 5076 Name_Entry *entry; 5077 size_t len; 5078 5079 len = strlen(name); 5080 entry = malloc(sizeof(Name_Entry) + len); 5081 5082 if (entry != NULL) { 5083 strcpy(entry->name, name); 5084 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5085 } 5086 } 5087 5088 static int 5089 object_match_name(const Obj_Entry *obj, const char *name) 5090 { 5091 Name_Entry *entry; 5092 5093 STAILQ_FOREACH(entry, &obj->names, link) { 5094 if (strcmp(name, entry->name) == 0) 5095 return (1); 5096 } 5097 return (0); 5098 } 5099 5100 static Obj_Entry * 5101 locate_dependency(const Obj_Entry *obj, const char *name) 5102 { 5103 const Objlist_Entry *entry; 5104 const Needed_Entry *needed; 5105 5106 STAILQ_FOREACH(entry, &list_main, link) { 5107 if (object_match_name(entry->obj, name)) 5108 return entry->obj; 5109 } 5110 5111 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5112 if (strcmp(obj->strtab + needed->name, name) == 0 || 5113 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5114 /* 5115 * If there is DT_NEEDED for the name we are looking for, 5116 * we are all set. Note that object might not be found if 5117 * dependency was not loaded yet, so the function can 5118 * return NULL here. This is expected and handled 5119 * properly by the caller. 5120 */ 5121 return (needed->obj); 5122 } 5123 } 5124 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5125 obj->path, name); 5126 rtld_die(); 5127 } 5128 5129 static int 5130 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5131 const Elf_Vernaux *vna) 5132 { 5133 const Elf_Verdef *vd; 5134 const char *vername; 5135 5136 vername = refobj->strtab + vna->vna_name; 5137 vd = depobj->verdef; 5138 if (vd == NULL) { 5139 _rtld_error("%s: version %s required by %s not defined", 5140 depobj->path, vername, refobj->path); 5141 return (-1); 5142 } 5143 for (;;) { 5144 if (vd->vd_version != VER_DEF_CURRENT) { 5145 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5146 depobj->path, vd->vd_version); 5147 return (-1); 5148 } 5149 if (vna->vna_hash == vd->vd_hash) { 5150 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5151 ((const char *)vd + vd->vd_aux); 5152 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5153 return (0); 5154 } 5155 if (vd->vd_next == 0) 5156 break; 5157 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5158 } 5159 if (vna->vna_flags & VER_FLG_WEAK) 5160 return (0); 5161 _rtld_error("%s: version %s required by %s not found", 5162 depobj->path, vername, refobj->path); 5163 return (-1); 5164 } 5165 5166 static int 5167 rtld_verify_object_versions(Obj_Entry *obj) 5168 { 5169 const Elf_Verneed *vn; 5170 const Elf_Verdef *vd; 5171 const Elf_Verdaux *vda; 5172 const Elf_Vernaux *vna; 5173 const Obj_Entry *depobj; 5174 int maxvernum, vernum; 5175 5176 if (obj->ver_checked) 5177 return (0); 5178 obj->ver_checked = true; 5179 5180 maxvernum = 0; 5181 /* 5182 * Walk over defined and required version records and figure out 5183 * max index used by any of them. Do very basic sanity checking 5184 * while there. 5185 */ 5186 vn = obj->verneed; 5187 while (vn != NULL) { 5188 if (vn->vn_version != VER_NEED_CURRENT) { 5189 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5190 obj->path, vn->vn_version); 5191 return (-1); 5192 } 5193 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5194 for (;;) { 5195 vernum = VER_NEED_IDX(vna->vna_other); 5196 if (vernum > maxvernum) 5197 maxvernum = vernum; 5198 if (vna->vna_next == 0) 5199 break; 5200 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5201 } 5202 if (vn->vn_next == 0) 5203 break; 5204 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5205 } 5206 5207 vd = obj->verdef; 5208 while (vd != NULL) { 5209 if (vd->vd_version != VER_DEF_CURRENT) { 5210 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5211 obj->path, vd->vd_version); 5212 return (-1); 5213 } 5214 vernum = VER_DEF_IDX(vd->vd_ndx); 5215 if (vernum > maxvernum) 5216 maxvernum = vernum; 5217 if (vd->vd_next == 0) 5218 break; 5219 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5220 } 5221 5222 if (maxvernum == 0) 5223 return (0); 5224 5225 /* 5226 * Store version information in array indexable by version index. 5227 * Verify that object version requirements are satisfied along the 5228 * way. 5229 */ 5230 obj->vernum = maxvernum + 1; 5231 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5232 5233 vd = obj->verdef; 5234 while (vd != NULL) { 5235 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5236 vernum = VER_DEF_IDX(vd->vd_ndx); 5237 assert(vernum <= maxvernum); 5238 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5239 obj->vertab[vernum].hash = vd->vd_hash; 5240 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5241 obj->vertab[vernum].file = NULL; 5242 obj->vertab[vernum].flags = 0; 5243 } 5244 if (vd->vd_next == 0) 5245 break; 5246 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5247 } 5248 5249 vn = obj->verneed; 5250 while (vn != NULL) { 5251 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5252 if (depobj == NULL) 5253 return (-1); 5254 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5255 for (;;) { 5256 if (check_object_provided_version(obj, depobj, vna)) 5257 return (-1); 5258 vernum = VER_NEED_IDX(vna->vna_other); 5259 assert(vernum <= maxvernum); 5260 obj->vertab[vernum].hash = vna->vna_hash; 5261 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5262 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5263 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5264 VER_INFO_HIDDEN : 0; 5265 if (vna->vna_next == 0) 5266 break; 5267 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5268 } 5269 if (vn->vn_next == 0) 5270 break; 5271 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5272 } 5273 return 0; 5274 } 5275 5276 static int 5277 rtld_verify_versions(const Objlist *objlist) 5278 { 5279 Objlist_Entry *entry; 5280 int rc; 5281 5282 rc = 0; 5283 STAILQ_FOREACH(entry, objlist, link) { 5284 /* 5285 * Skip dummy objects or objects that have their version requirements 5286 * already checked. 5287 */ 5288 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5289 continue; 5290 if (rtld_verify_object_versions(entry->obj) == -1) { 5291 rc = -1; 5292 if (ld_tracing == NULL) 5293 break; 5294 } 5295 } 5296 if (rc == 0 || ld_tracing != NULL) 5297 rc = rtld_verify_object_versions(&obj_rtld); 5298 return rc; 5299 } 5300 5301 const Ver_Entry * 5302 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5303 { 5304 Elf_Versym vernum; 5305 5306 if (obj->vertab) { 5307 vernum = VER_NDX(obj->versyms[symnum]); 5308 if (vernum >= obj->vernum) { 5309 _rtld_error("%s: symbol %s has wrong verneed value %d", 5310 obj->path, obj->strtab + symnum, vernum); 5311 } else if (obj->vertab[vernum].hash != 0) { 5312 return &obj->vertab[vernum]; 5313 } 5314 } 5315 return NULL; 5316 } 5317 5318 int 5319 _rtld_get_stack_prot(void) 5320 { 5321 5322 return (stack_prot); 5323 } 5324 5325 int 5326 _rtld_is_dlopened(void *arg) 5327 { 5328 Obj_Entry *obj; 5329 RtldLockState lockstate; 5330 int res; 5331 5332 rlock_acquire(rtld_bind_lock, &lockstate); 5333 obj = dlcheck(arg); 5334 if (obj == NULL) 5335 obj = obj_from_addr(arg); 5336 if (obj == NULL) { 5337 _rtld_error("No shared object contains address"); 5338 lock_release(rtld_bind_lock, &lockstate); 5339 return (-1); 5340 } 5341 res = obj->dlopened ? 1 : 0; 5342 lock_release(rtld_bind_lock, &lockstate); 5343 return (res); 5344 } 5345 5346 int 5347 obj_enforce_relro(Obj_Entry *obj) 5348 { 5349 5350 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5351 PROT_READ) == -1) { 5352 _rtld_error("%s: Cannot enforce relro protection: %s", 5353 obj->path, rtld_strerror(errno)); 5354 return (-1); 5355 } 5356 return (0); 5357 } 5358 5359 static void 5360 map_stacks_exec(RtldLockState *lockstate) 5361 { 5362 void (*thr_map_stacks_exec)(void); 5363 5364 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5365 return; 5366 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5367 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5368 if (thr_map_stacks_exec != NULL) { 5369 stack_prot |= PROT_EXEC; 5370 thr_map_stacks_exec(); 5371 } 5372 } 5373 5374 void 5375 symlook_init(SymLook *dst, const char *name) 5376 { 5377 5378 bzero(dst, sizeof(*dst)); 5379 dst->name = name; 5380 dst->hash = elf_hash(name); 5381 dst->hash_gnu = gnu_hash(name); 5382 } 5383 5384 static void 5385 symlook_init_from_req(SymLook *dst, const SymLook *src) 5386 { 5387 5388 dst->name = src->name; 5389 dst->hash = src->hash; 5390 dst->hash_gnu = src->hash_gnu; 5391 dst->ventry = src->ventry; 5392 dst->flags = src->flags; 5393 dst->defobj_out = NULL; 5394 dst->sym_out = NULL; 5395 dst->lockstate = src->lockstate; 5396 } 5397 5398 static int 5399 open_binary_fd(const char *argv0, bool search_in_path) 5400 { 5401 char *pathenv, *pe, binpath[PATH_MAX]; 5402 int fd; 5403 5404 if (search_in_path && strchr(argv0, '/') == NULL) { 5405 pathenv = getenv("PATH"); 5406 if (pathenv == NULL) { 5407 _rtld_error("-p and no PATH environment variable"); 5408 rtld_die(); 5409 } 5410 pathenv = strdup(pathenv); 5411 if (pathenv == NULL) { 5412 _rtld_error("Cannot allocate memory"); 5413 rtld_die(); 5414 } 5415 fd = -1; 5416 errno = ENOENT; 5417 while ((pe = strsep(&pathenv, ":")) != NULL) { 5418 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5419 sizeof(binpath)) 5420 continue; 5421 if (binpath[0] != '\0' && 5422 strlcat(binpath, "/", sizeof(binpath)) >= 5423 sizeof(binpath)) 5424 continue; 5425 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5426 sizeof(binpath)) 5427 continue; 5428 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5429 if (fd != -1 || errno != ENOENT) 5430 break; 5431 } 5432 free(pathenv); 5433 } else { 5434 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5435 } 5436 5437 if (fd == -1) { 5438 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5439 rtld_die(); 5440 } 5441 return (fd); 5442 } 5443 5444 /* 5445 * Parse a set of command-line arguments. 5446 */ 5447 static int 5448 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5449 { 5450 const char *arg; 5451 int fd, i, j, arglen; 5452 char opt; 5453 5454 dbg("Parsing command-line arguments"); 5455 *use_pathp = false; 5456 *fdp = -1; 5457 5458 for (i = 1; i < argc; i++ ) { 5459 arg = argv[i]; 5460 dbg("argv[%d]: '%s'", i, arg); 5461 5462 /* 5463 * rtld arguments end with an explicit "--" or with the first 5464 * non-prefixed argument. 5465 */ 5466 if (strcmp(arg, "--") == 0) { 5467 i++; 5468 break; 5469 } 5470 if (arg[0] != '-') 5471 break; 5472 5473 /* 5474 * All other arguments are single-character options that can 5475 * be combined, so we need to search through `arg` for them. 5476 */ 5477 arglen = strlen(arg); 5478 for (j = 1; j < arglen; j++) { 5479 opt = arg[j]; 5480 if (opt == 'h') { 5481 print_usage(argv[0]); 5482 _exit(0); 5483 } else if (opt == 'f') { 5484 /* 5485 * -f XX can be used to specify a descriptor for the 5486 * binary named at the command line (i.e., the later 5487 * argument will specify the process name but the 5488 * descriptor is what will actually be executed) 5489 */ 5490 if (j != arglen - 1) { 5491 /* -f must be the last option in, e.g., -abcf */ 5492 _rtld_error("Invalid options: %s", arg); 5493 rtld_die(); 5494 } 5495 i++; 5496 fd = parse_integer(argv[i]); 5497 if (fd == -1) { 5498 _rtld_error("Invalid file descriptor: '%s'", 5499 argv[i]); 5500 rtld_die(); 5501 } 5502 *fdp = fd; 5503 break; 5504 } else if (opt == 'p') { 5505 *use_pathp = true; 5506 } else { 5507 _rtld_error("Invalid argument: '%s'", arg); 5508 print_usage(argv[0]); 5509 rtld_die(); 5510 } 5511 } 5512 } 5513 5514 return (i); 5515 } 5516 5517 /* 5518 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5519 */ 5520 static int 5521 parse_integer(const char *str) 5522 { 5523 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5524 const char *orig; 5525 int n; 5526 char c; 5527 5528 orig = str; 5529 n = 0; 5530 for (c = *str; c != '\0'; c = *++str) { 5531 if (c < '0' || c > '9') 5532 return (-1); 5533 5534 n *= RADIX; 5535 n += c - '0'; 5536 } 5537 5538 /* Make sure we actually parsed something. */ 5539 if (str == orig) 5540 return (-1); 5541 return (n); 5542 } 5543 5544 static void 5545 print_usage(const char *argv0) 5546 { 5547 5548 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5549 "\n" 5550 "Options:\n" 5551 " -h Display this help message\n" 5552 " -p Search in PATH for named binary\n" 5553 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5554 " -- End of RTLD options\n" 5555 " <binary> Name of process to execute\n" 5556 " <args> Arguments to the executed process\n", argv0); 5557 } 5558 5559 /* 5560 * Overrides for libc_pic-provided functions. 5561 */ 5562 5563 int 5564 __getosreldate(void) 5565 { 5566 size_t len; 5567 int oid[2]; 5568 int error, osrel; 5569 5570 if (osreldate != 0) 5571 return (osreldate); 5572 5573 oid[0] = CTL_KERN; 5574 oid[1] = KERN_OSRELDATE; 5575 osrel = 0; 5576 len = sizeof(osrel); 5577 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5578 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5579 osreldate = osrel; 5580 return (osreldate); 5581 } 5582 5583 void 5584 exit(int status) 5585 { 5586 5587 _exit(status); 5588 } 5589 5590 void (*__cleanup)(void); 5591 int __isthreaded = 0; 5592 int _thread_autoinit_dummy_decl = 1; 5593 5594 /* 5595 * No unresolved symbols for rtld. 5596 */ 5597 void 5598 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5599 { 5600 } 5601 5602 const char * 5603 rtld_strerror(int errnum) 5604 { 5605 5606 if (errnum < 0 || errnum >= sys_nerr) 5607 return ("Unknown error"); 5608 return (sys_errlist[errnum]); 5609 } 5610