1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_utrace.h" 70 #include "notes.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 81 const Elf_Dyn **, const Elf_Dyn **); 82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 83 const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static int dlclose_locked(void *, RtldLockState *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *, int *); 97 static const char *gethints(bool); 98 static void hold_object(Obj_Entry *); 99 static void unhold_object(Obj_Entry *); 100 static void init_dag(Obj_Entry *); 101 static void init_marker(Obj_Entry *); 102 static void init_pagesizes(Elf_Auxinfo **aux_info); 103 static void init_rtld(caddr_t, Elf_Auxinfo **); 104 static void initlist_add_neededs(Needed_Entry *, Objlist *); 105 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 106 static void linkmap_add(Obj_Entry *); 107 static void linkmap_delete(Obj_Entry *); 108 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 109 static void unload_filtees(Obj_Entry *, RtldLockState *); 110 static int load_needed_objects(Obj_Entry *, int); 111 static int load_preload_objects(void); 112 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 113 static void map_stacks_exec(RtldLockState *); 114 static int obj_enforce_relro(Obj_Entry *); 115 static Obj_Entry *obj_from_addr(const void *); 116 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 117 static void objlist_call_init(Objlist *, RtldLockState *); 118 static void objlist_clear(Objlist *); 119 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 120 static void objlist_init(Objlist *); 121 static void objlist_push_head(Objlist *, Obj_Entry *); 122 static void objlist_push_tail(Objlist *, Obj_Entry *); 123 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 124 static void objlist_remove(Objlist *, Obj_Entry *); 125 static int open_binary_fd(const char *argv0, bool search_in_path); 126 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 127 static int parse_integer(const char *); 128 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 129 static void print_usage(const char *argv0); 130 static void release_object(Obj_Entry *); 131 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 132 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 133 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 134 int flags, RtldLockState *lockstate); 135 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 136 RtldLockState *); 137 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 138 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 139 int flags, RtldLockState *lockstate); 140 static int rtld_dirname(const char *, char *); 141 static int rtld_dirname_abs(const char *, char *); 142 static void *rtld_dlopen(const char *name, int fd, int mode); 143 static void rtld_exit(void); 144 static char *search_library_path(const char *, const char *, const char *, 145 int *); 146 static char *search_library_pathfds(const char *, const char *, int *); 147 static const void **get_program_var_addr(const char *, RtldLockState *); 148 static void set_program_var(const char *, const void *); 149 static int symlook_default(SymLook *, const Obj_Entry *refobj); 150 static int symlook_global(SymLook *, DoneList *); 151 static void symlook_init_from_req(SymLook *, const SymLook *); 152 static int symlook_list(SymLook *, const Objlist *, DoneList *); 153 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 154 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 155 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 156 static void trace_loaded_objects(Obj_Entry *); 157 static void unlink_object(Obj_Entry *); 158 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 159 static void unref_dag(Obj_Entry *); 160 static void ref_dag(Obj_Entry *); 161 static char *origin_subst_one(Obj_Entry *, char *, const char *, 162 const char *, bool); 163 static char *origin_subst(Obj_Entry *, char *); 164 static bool obj_resolve_origin(Obj_Entry *obj); 165 static void preinit_main(void); 166 static int rtld_verify_versions(const Objlist *); 167 static int rtld_verify_object_versions(Obj_Entry *); 168 static void object_add_name(Obj_Entry *, const char *); 169 static int object_match_name(const Obj_Entry *, const char *); 170 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 171 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 172 struct dl_phdr_info *phdr_info); 173 static uint32_t gnu_hash(const char *); 174 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 175 const unsigned long); 176 177 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 178 void _r_debug_postinit(struct link_map *) __noinline __exported; 179 180 int __sys_openat(int, const char *, int, ...); 181 182 /* 183 * Data declarations. 184 */ 185 static char *error_message; /* Message for dlerror(), or NULL */ 186 struct r_debug r_debug __exported; /* for GDB; */ 187 static bool libmap_disable; /* Disable libmap */ 188 static bool ld_loadfltr; /* Immediate filters processing */ 189 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 190 static bool trust; /* False for setuid and setgid programs */ 191 static bool dangerous_ld_env; /* True if environment variables have been 192 used to affect the libraries loaded */ 193 bool ld_bind_not; /* Disable PLT update */ 194 static char *ld_bind_now; /* Environment variable for immediate binding */ 195 static char *ld_debug; /* Environment variable for debugging */ 196 static char *ld_library_path; /* Environment variable for search path */ 197 static char *ld_library_dirs; /* Environment variable for library descriptors */ 198 static char *ld_preload; /* Environment variable for libraries to 199 load first */ 200 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 201 static char *ld_tracing; /* Called from ldd to print libs */ 202 static char *ld_utrace; /* Use utrace() to log events. */ 203 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 204 static Obj_Entry *obj_main; /* The main program shared object */ 205 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 206 static unsigned int obj_count; /* Number of objects in obj_list */ 207 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 208 209 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 210 STAILQ_HEAD_INITIALIZER(list_global); 211 static Objlist list_main = /* Objects loaded at program startup */ 212 STAILQ_HEAD_INITIALIZER(list_main); 213 static Objlist list_fini = /* Objects needing fini() calls */ 214 STAILQ_HEAD_INITIALIZER(list_fini); 215 216 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 217 218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 219 220 extern Elf_Dyn _DYNAMIC; 221 #pragma weak _DYNAMIC 222 223 int dlclose(void *) __exported; 224 char *dlerror(void) __exported; 225 void *dlopen(const char *, int) __exported; 226 void *fdlopen(int, int) __exported; 227 void *dlsym(void *, const char *) __exported; 228 dlfunc_t dlfunc(void *, const char *) __exported; 229 void *dlvsym(void *, const char *, const char *) __exported; 230 int dladdr(const void *, Dl_info *) __exported; 231 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 232 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 233 int dlinfo(void *, int , void *) __exported; 234 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 235 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 236 int _rtld_get_stack_prot(void) __exported; 237 int _rtld_is_dlopened(void *) __exported; 238 void _rtld_error(const char *, ...) __exported; 239 240 int npagesizes, osreldate; 241 size_t *pagesizes; 242 243 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 244 static int max_stack_flags; 245 246 /* 247 * Global declarations normally provided by crt1. The dynamic linker is 248 * not built with crt1, so we have to provide them ourselves. 249 */ 250 char *__progname; 251 char **environ; 252 253 /* 254 * Used to pass argc, argv to init functions. 255 */ 256 int main_argc; 257 char **main_argv; 258 259 /* 260 * Globals to control TLS allocation. 261 */ 262 size_t tls_last_offset; /* Static TLS offset of last module */ 263 size_t tls_last_size; /* Static TLS size of last module */ 264 size_t tls_static_space; /* Static TLS space allocated */ 265 size_t tls_static_max_align; 266 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 267 int tls_max_index = 1; /* Largest module index allocated */ 268 269 bool ld_library_path_rpath = false; 270 271 /* 272 * Globals for path names, and such 273 */ 274 char *ld_elf_hints_default = _PATH_ELF_HINTS; 275 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 276 char *ld_path_rtld = _PATH_RTLD; 277 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 278 char *ld_env_prefix = LD_; 279 280 /* 281 * Fill in a DoneList with an allocation large enough to hold all of 282 * the currently-loaded objects. Keep this as a macro since it calls 283 * alloca and we want that to occur within the scope of the caller. 284 */ 285 #define donelist_init(dlp) \ 286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 287 assert((dlp)->objs != NULL), \ 288 (dlp)->num_alloc = obj_count, \ 289 (dlp)->num_used = 0) 290 291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294 } while (0) 295 296 static void 297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299 { 300 struct utrace_rtld ut; 301 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 302 303 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 #ifdef RTLD_VARIANT_ENV_NAMES 316 /* 317 * construct the env variable based on the type of binary that's 318 * running. 319 */ 320 static inline const char * 321 _LD(const char *var) 322 { 323 static char buffer[128]; 324 325 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 326 strlcat(buffer, var, sizeof(buffer)); 327 return (buffer); 328 } 329 #else 330 #define _LD(x) LD_ x 331 #endif 332 333 /* 334 * Main entry point for dynamic linking. The first argument is the 335 * stack pointer. The stack is expected to be laid out as described 336 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 337 * Specifically, the stack pointer points to a word containing 338 * ARGC. Following that in the stack is a null-terminated sequence 339 * of pointers to argument strings. Then comes a null-terminated 340 * sequence of pointers to environment strings. Finally, there is a 341 * sequence of "auxiliary vector" entries. 342 * 343 * The second argument points to a place to store the dynamic linker's 344 * exit procedure pointer and the third to a place to store the main 345 * program's object. 346 * 347 * The return value is the main program's entry point. 348 */ 349 func_ptr_type 350 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 351 { 352 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 353 Objlist_Entry *entry; 354 Obj_Entry *last_interposer, *obj, *preload_tail; 355 const Elf_Phdr *phdr; 356 Objlist initlist; 357 RtldLockState lockstate; 358 struct stat st; 359 Elf_Addr *argcp; 360 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 361 caddr_t imgentry; 362 char buf[MAXPATHLEN]; 363 int argc, fd, i, phnum, rtld_argc; 364 bool dir_enable, explicit_fd, search_in_path; 365 366 /* 367 * On entry, the dynamic linker itself has not been relocated yet. 368 * Be very careful not to reference any global data until after 369 * init_rtld has returned. It is OK to reference file-scope statics 370 * and string constants, and to call static and global functions. 371 */ 372 373 /* Find the auxiliary vector on the stack. */ 374 argcp = sp; 375 argc = *sp++; 376 argv = (char **) sp; 377 sp += argc + 1; /* Skip over arguments and NULL terminator */ 378 env = (char **) sp; 379 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 380 ; 381 aux = (Elf_Auxinfo *) sp; 382 383 /* Digest the auxiliary vector. */ 384 for (i = 0; i < AT_COUNT; i++) 385 aux_info[i] = NULL; 386 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 387 if (auxp->a_type < AT_COUNT) 388 aux_info[auxp->a_type] = auxp; 389 } 390 391 /* Initialize and relocate ourselves. */ 392 assert(aux_info[AT_BASE] != NULL); 393 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 394 395 __progname = obj_rtld.path; 396 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 397 environ = env; 398 main_argc = argc; 399 main_argv = argv; 400 401 trust = !issetugid(); 402 403 md_abi_variant_hook(aux_info); 404 405 fd = -1; 406 if (aux_info[AT_EXECFD] != NULL) { 407 fd = aux_info[AT_EXECFD]->a_un.a_val; 408 } else { 409 assert(aux_info[AT_PHDR] != NULL); 410 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 411 if (phdr == obj_rtld.phdr) { 412 if (!trust) { 413 _rtld_error("Tainted process refusing to run binary %s", 414 argv0); 415 rtld_die(); 416 } 417 dbg("opening main program in direct exec mode"); 418 if (argc >= 2) { 419 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 420 argv0 = argv[rtld_argc]; 421 explicit_fd = (fd != -1); 422 if (!explicit_fd) 423 fd = open_binary_fd(argv0, search_in_path); 424 if (fstat(fd, &st) == -1) { 425 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 426 explicit_fd ? "user-provided descriptor" : argv0, 427 rtld_strerror(errno)); 428 rtld_die(); 429 } 430 431 /* 432 * Rough emulation of the permission checks done by 433 * execve(2), only Unix DACs are checked, ACLs are 434 * ignored. Preserve the semantic of disabling owner 435 * to execute if owner x bit is cleared, even if 436 * others x bit is enabled. 437 * mmap(2) does not allow to mmap with PROT_EXEC if 438 * binary' file comes from noexec mount. We cannot 439 * set VV_TEXT on the binary. 440 */ 441 dir_enable = false; 442 if (st.st_uid == geteuid()) { 443 if ((st.st_mode & S_IXUSR) != 0) 444 dir_enable = true; 445 } else if (st.st_gid == getegid()) { 446 if ((st.st_mode & S_IXGRP) != 0) 447 dir_enable = true; 448 } else if ((st.st_mode & S_IXOTH) != 0) { 449 dir_enable = true; 450 } 451 if (!dir_enable) { 452 _rtld_error("No execute permission for binary %s", 453 argv0); 454 rtld_die(); 455 } 456 457 /* 458 * For direct exec mode, argv[0] is the interpreter 459 * name, we must remove it and shift arguments left 460 * before invoking binary main. Since stack layout 461 * places environment pointers and aux vectors right 462 * after the terminating NULL, we must shift 463 * environment and aux as well. 464 */ 465 main_argc = argc - rtld_argc; 466 for (i = 0; i <= main_argc; i++) 467 argv[i] = argv[i + rtld_argc]; 468 *argcp -= rtld_argc; 469 environ = env = envp = argv + main_argc + 1; 470 do { 471 *envp = *(envp + rtld_argc); 472 envp++; 473 } while (*envp != NULL); 474 aux = auxp = (Elf_Auxinfo *)envp; 475 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 476 for (;; auxp++, auxpf++) { 477 *auxp = *auxpf; 478 if (auxp->a_type == AT_NULL) 479 break; 480 } 481 } else { 482 _rtld_error("No binary"); 483 rtld_die(); 484 } 485 } 486 } 487 488 ld_bind_now = getenv(_LD("BIND_NOW")); 489 490 /* 491 * If the process is tainted, then we un-set the dangerous environment 492 * variables. The process will be marked as tainted until setuid(2) 493 * is called. If any child process calls setuid(2) we do not want any 494 * future processes to honor the potentially un-safe variables. 495 */ 496 if (!trust) { 497 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 498 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 499 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 500 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 501 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 502 _rtld_error("environment corrupt; aborting"); 503 rtld_die(); 504 } 505 } 506 ld_debug = getenv(_LD("DEBUG")); 507 if (ld_bind_now == NULL) 508 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 509 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 510 libmap_override = getenv(_LD("LIBMAP")); 511 ld_library_path = getenv(_LD("LIBRARY_PATH")); 512 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 513 ld_preload = getenv(_LD("PRELOAD")); 514 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 515 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 516 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 517 if (library_path_rpath != NULL) { 518 if (library_path_rpath[0] == 'y' || 519 library_path_rpath[0] == 'Y' || 520 library_path_rpath[0] == '1') 521 ld_library_path_rpath = true; 522 else 523 ld_library_path_rpath = false; 524 } 525 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 526 (ld_library_path != NULL) || (ld_preload != NULL) || 527 (ld_elf_hints_path != NULL) || ld_loadfltr; 528 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 529 ld_utrace = getenv(_LD("UTRACE")); 530 531 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 532 ld_elf_hints_path = ld_elf_hints_default; 533 534 if (ld_debug != NULL && *ld_debug != '\0') 535 debug = 1; 536 dbg("%s is initialized, base address = %p", __progname, 537 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 538 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 539 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 540 541 dbg("initializing thread locks"); 542 lockdflt_init(); 543 544 /* 545 * Load the main program, or process its program header if it is 546 * already loaded. 547 */ 548 if (fd != -1) { /* Load the main program. */ 549 dbg("loading main program"); 550 obj_main = map_object(fd, argv0, NULL); 551 close(fd); 552 if (obj_main == NULL) 553 rtld_die(); 554 max_stack_flags = obj_main->stack_flags; 555 } else { /* Main program already loaded. */ 556 dbg("processing main program's program header"); 557 assert(aux_info[AT_PHDR] != NULL); 558 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 559 assert(aux_info[AT_PHNUM] != NULL); 560 phnum = aux_info[AT_PHNUM]->a_un.a_val; 561 assert(aux_info[AT_PHENT] != NULL); 562 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 563 assert(aux_info[AT_ENTRY] != NULL); 564 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 565 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 566 rtld_die(); 567 } 568 569 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 570 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 571 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 572 if (kexecpath[0] == '/') 573 obj_main->path = kexecpath; 574 else if (getcwd(buf, sizeof(buf)) == NULL || 575 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 576 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 577 obj_main->path = xstrdup(argv0); 578 else 579 obj_main->path = xstrdup(buf); 580 } else { 581 dbg("No AT_EXECPATH or direct exec"); 582 obj_main->path = xstrdup(argv0); 583 } 584 dbg("obj_main path %s", obj_main->path); 585 obj_main->mainprog = true; 586 587 if (aux_info[AT_STACKPROT] != NULL && 588 aux_info[AT_STACKPROT]->a_un.a_val != 0) 589 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 590 591 #ifndef COMPAT_32BIT 592 /* 593 * Get the actual dynamic linker pathname from the executable if 594 * possible. (It should always be possible.) That ensures that 595 * gdb will find the right dynamic linker even if a non-standard 596 * one is being used. 597 */ 598 if (obj_main->interp != NULL && 599 strcmp(obj_main->interp, obj_rtld.path) != 0) { 600 free(obj_rtld.path); 601 obj_rtld.path = xstrdup(obj_main->interp); 602 __progname = obj_rtld.path; 603 } 604 #endif 605 606 digest_dynamic(obj_main, 0); 607 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 608 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 609 obj_main->dynsymcount); 610 611 linkmap_add(obj_main); 612 linkmap_add(&obj_rtld); 613 614 /* Link the main program into the list of objects. */ 615 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 616 obj_count++; 617 obj_loads++; 618 619 /* Initialize a fake symbol for resolving undefined weak references. */ 620 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 621 sym_zero.st_shndx = SHN_UNDEF; 622 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 623 624 if (!libmap_disable) 625 libmap_disable = (bool)lm_init(libmap_override); 626 627 dbg("loading LD_PRELOAD libraries"); 628 if (load_preload_objects() == -1) 629 rtld_die(); 630 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 631 632 dbg("loading needed objects"); 633 if (load_needed_objects(obj_main, 0) == -1) 634 rtld_die(); 635 636 /* Make a list of all objects loaded at startup. */ 637 last_interposer = obj_main; 638 TAILQ_FOREACH(obj, &obj_list, next) { 639 if (obj->marker) 640 continue; 641 if (obj->z_interpose && obj != obj_main) { 642 objlist_put_after(&list_main, last_interposer, obj); 643 last_interposer = obj; 644 } else { 645 objlist_push_tail(&list_main, obj); 646 } 647 obj->refcount++; 648 } 649 650 dbg("checking for required versions"); 651 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 652 rtld_die(); 653 654 if (ld_tracing) { /* We're done */ 655 trace_loaded_objects(obj_main); 656 exit(0); 657 } 658 659 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 660 dump_relocations(obj_main); 661 exit (0); 662 } 663 664 /* 665 * Processing tls relocations requires having the tls offsets 666 * initialized. Prepare offsets before starting initial 667 * relocation processing. 668 */ 669 dbg("initializing initial thread local storage offsets"); 670 STAILQ_FOREACH(entry, &list_main, link) { 671 /* 672 * Allocate all the initial objects out of the static TLS 673 * block even if they didn't ask for it. 674 */ 675 allocate_tls_offset(entry->obj); 676 } 677 678 if (relocate_objects(obj_main, 679 ld_bind_now != NULL && *ld_bind_now != '\0', 680 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 681 rtld_die(); 682 683 dbg("doing copy relocations"); 684 if (do_copy_relocations(obj_main) == -1) 685 rtld_die(); 686 687 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 688 dump_relocations(obj_main); 689 exit (0); 690 } 691 692 ifunc_init(aux); 693 694 /* 695 * Setup TLS for main thread. This must be done after the 696 * relocations are processed, since tls initialization section 697 * might be the subject for relocations. 698 */ 699 dbg("initializing initial thread local storage"); 700 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 701 702 dbg("initializing key program variables"); 703 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 704 set_program_var("environ", env); 705 set_program_var("__elf_aux_vector", aux); 706 707 /* Make a list of init functions to call. */ 708 objlist_init(&initlist); 709 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 710 preload_tail, &initlist); 711 712 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 713 714 map_stacks_exec(NULL); 715 716 dbg("resolving ifuncs"); 717 if (resolve_objects_ifunc(obj_main, 718 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 719 NULL) == -1) 720 rtld_die(); 721 722 dbg("enforcing main obj relro"); 723 if (obj_enforce_relro(obj_main) == -1) 724 rtld_die(); 725 726 if (!obj_main->crt_no_init) { 727 /* 728 * Make sure we don't call the main program's init and fini 729 * functions for binaries linked with old crt1 which calls 730 * _init itself. 731 */ 732 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 733 obj_main->preinit_array = obj_main->init_array = 734 obj_main->fini_array = (Elf_Addr)NULL; 735 } 736 737 /* 738 * Execute MD initializers required before we call the objects' 739 * init functions. 740 */ 741 pre_init(); 742 743 wlock_acquire(rtld_bind_lock, &lockstate); 744 if (obj_main->crt_no_init) 745 preinit_main(); 746 objlist_call_init(&initlist, &lockstate); 747 _r_debug_postinit(&obj_main->linkmap); 748 objlist_clear(&initlist); 749 dbg("loading filtees"); 750 TAILQ_FOREACH(obj, &obj_list, next) { 751 if (obj->marker) 752 continue; 753 if (ld_loadfltr || obj->z_loadfltr) 754 load_filtees(obj, 0, &lockstate); 755 } 756 lock_release(rtld_bind_lock, &lockstate); 757 758 dbg("transferring control to program entry point = %p", obj_main->entry); 759 760 /* Return the exit procedure and the program entry point. */ 761 *exit_proc = rtld_exit; 762 *objp = obj_main; 763 return (func_ptr_type) obj_main->entry; 764 } 765 766 void * 767 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 768 { 769 void *ptr; 770 Elf_Addr target; 771 772 ptr = (void *)make_function_pointer(def, obj); 773 target = call_ifunc_resolver(ptr); 774 return ((void *)target); 775 } 776 777 /* 778 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 779 * Changes to this function should be applied there as well. 780 */ 781 Elf_Addr 782 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 783 { 784 const Elf_Rel *rel; 785 const Elf_Sym *def; 786 const Obj_Entry *defobj; 787 Elf_Addr *where; 788 Elf_Addr target; 789 RtldLockState lockstate; 790 791 rlock_acquire(rtld_bind_lock, &lockstate); 792 if (sigsetjmp(lockstate.env, 0) != 0) 793 lock_upgrade(rtld_bind_lock, &lockstate); 794 if (obj->pltrel) 795 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 796 else 797 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 798 799 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 800 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 801 NULL, &lockstate); 802 if (def == NULL) 803 rtld_die(); 804 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 805 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 806 else 807 target = (Elf_Addr)(defobj->relocbase + def->st_value); 808 809 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 810 defobj->strtab + def->st_name, basename(obj->path), 811 (void *)target, basename(defobj->path)); 812 813 /* 814 * Write the new contents for the jmpslot. Note that depending on 815 * architecture, the value which we need to return back to the 816 * lazy binding trampoline may or may not be the target 817 * address. The value returned from reloc_jmpslot() is the value 818 * that the trampoline needs. 819 */ 820 target = reloc_jmpslot(where, target, defobj, obj, rel); 821 lock_release(rtld_bind_lock, &lockstate); 822 return target; 823 } 824 825 /* 826 * Error reporting function. Use it like printf. If formats the message 827 * into a buffer, and sets things up so that the next call to dlerror() 828 * will return the message. 829 */ 830 void 831 _rtld_error(const char *fmt, ...) 832 { 833 static char buf[512]; 834 va_list ap; 835 836 va_start(ap, fmt); 837 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 838 error_message = buf; 839 va_end(ap); 840 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 841 } 842 843 /* 844 * Return a dynamically-allocated copy of the current error message, if any. 845 */ 846 static char * 847 errmsg_save(void) 848 { 849 return error_message == NULL ? NULL : xstrdup(error_message); 850 } 851 852 /* 853 * Restore the current error message from a copy which was previously saved 854 * by errmsg_save(). The copy is freed. 855 */ 856 static void 857 errmsg_restore(char *saved_msg) 858 { 859 if (saved_msg == NULL) 860 error_message = NULL; 861 else { 862 _rtld_error("%s", saved_msg); 863 free(saved_msg); 864 } 865 } 866 867 static const char * 868 basename(const char *name) 869 { 870 const char *p = strrchr(name, '/'); 871 return p != NULL ? p + 1 : name; 872 } 873 874 static struct utsname uts; 875 876 static char * 877 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 878 const char *subst, bool may_free) 879 { 880 char *p, *p1, *res, *resp; 881 int subst_len, kw_len, subst_count, old_len, new_len; 882 883 kw_len = strlen(kw); 884 885 /* 886 * First, count the number of the keyword occurrences, to 887 * preallocate the final string. 888 */ 889 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 890 p1 = strstr(p, kw); 891 if (p1 == NULL) 892 break; 893 } 894 895 /* 896 * If the keyword is not found, just return. 897 * 898 * Return non-substituted string if resolution failed. We 899 * cannot do anything more reasonable, the failure mode of the 900 * caller is unresolved library anyway. 901 */ 902 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 903 return (may_free ? real : xstrdup(real)); 904 if (obj != NULL) 905 subst = obj->origin_path; 906 907 /* 908 * There is indeed something to substitute. Calculate the 909 * length of the resulting string, and allocate it. 910 */ 911 subst_len = strlen(subst); 912 old_len = strlen(real); 913 new_len = old_len + (subst_len - kw_len) * subst_count; 914 res = xmalloc(new_len + 1); 915 916 /* 917 * Now, execute the substitution loop. 918 */ 919 for (p = real, resp = res, *resp = '\0';;) { 920 p1 = strstr(p, kw); 921 if (p1 != NULL) { 922 /* Copy the prefix before keyword. */ 923 memcpy(resp, p, p1 - p); 924 resp += p1 - p; 925 /* Keyword replacement. */ 926 memcpy(resp, subst, subst_len); 927 resp += subst_len; 928 *resp = '\0'; 929 p = p1 + kw_len; 930 } else 931 break; 932 } 933 934 /* Copy to the end of string and finish. */ 935 strcat(resp, p); 936 if (may_free) 937 free(real); 938 return (res); 939 } 940 941 static char * 942 origin_subst(Obj_Entry *obj, char *real) 943 { 944 char *res1, *res2, *res3, *res4; 945 946 if (obj == NULL || !trust) 947 return (xstrdup(real)); 948 if (uts.sysname[0] == '\0') { 949 if (uname(&uts) != 0) { 950 _rtld_error("utsname failed: %d", errno); 951 return (NULL); 952 } 953 } 954 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 955 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 956 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 957 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 958 return (res4); 959 } 960 961 void 962 rtld_die(void) 963 { 964 const char *msg = dlerror(); 965 966 if (msg == NULL) 967 msg = "Fatal error"; 968 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 969 rtld_fdputstr(STDERR_FILENO, msg); 970 rtld_fdputchar(STDERR_FILENO, '\n'); 971 _exit(1); 972 } 973 974 /* 975 * Process a shared object's DYNAMIC section, and save the important 976 * information in its Obj_Entry structure. 977 */ 978 static void 979 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 980 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 981 { 982 const Elf_Dyn *dynp; 983 Needed_Entry **needed_tail = &obj->needed; 984 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 985 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 986 const Elf_Hashelt *hashtab; 987 const Elf32_Word *hashval; 988 Elf32_Word bkt, nmaskwords; 989 int bloom_size32; 990 int plttype = DT_REL; 991 992 *dyn_rpath = NULL; 993 *dyn_soname = NULL; 994 *dyn_runpath = NULL; 995 996 obj->bind_now = false; 997 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 998 switch (dynp->d_tag) { 999 1000 case DT_REL: 1001 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1002 break; 1003 1004 case DT_RELSZ: 1005 obj->relsize = dynp->d_un.d_val; 1006 break; 1007 1008 case DT_RELENT: 1009 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1010 break; 1011 1012 case DT_JMPREL: 1013 obj->pltrel = (const Elf_Rel *) 1014 (obj->relocbase + dynp->d_un.d_ptr); 1015 break; 1016 1017 case DT_PLTRELSZ: 1018 obj->pltrelsize = dynp->d_un.d_val; 1019 break; 1020 1021 case DT_RELA: 1022 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1023 break; 1024 1025 case DT_RELASZ: 1026 obj->relasize = dynp->d_un.d_val; 1027 break; 1028 1029 case DT_RELAENT: 1030 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1031 break; 1032 1033 case DT_PLTREL: 1034 plttype = dynp->d_un.d_val; 1035 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1036 break; 1037 1038 case DT_SYMTAB: 1039 obj->symtab = (const Elf_Sym *) 1040 (obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_SYMENT: 1044 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1045 break; 1046 1047 case DT_STRTAB: 1048 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1049 break; 1050 1051 case DT_STRSZ: 1052 obj->strsize = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_VERNEED: 1056 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1057 dynp->d_un.d_val); 1058 break; 1059 1060 case DT_VERNEEDNUM: 1061 obj->verneednum = dynp->d_un.d_val; 1062 break; 1063 1064 case DT_VERDEF: 1065 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1066 dynp->d_un.d_val); 1067 break; 1068 1069 case DT_VERDEFNUM: 1070 obj->verdefnum = dynp->d_un.d_val; 1071 break; 1072 1073 case DT_VERSYM: 1074 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1075 dynp->d_un.d_val); 1076 break; 1077 1078 case DT_HASH: 1079 { 1080 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1081 dynp->d_un.d_ptr); 1082 obj->nbuckets = hashtab[0]; 1083 obj->nchains = hashtab[1]; 1084 obj->buckets = hashtab + 2; 1085 obj->chains = obj->buckets + obj->nbuckets; 1086 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1087 obj->buckets != NULL; 1088 } 1089 break; 1090 1091 case DT_GNU_HASH: 1092 { 1093 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1094 dynp->d_un.d_ptr); 1095 obj->nbuckets_gnu = hashtab[0]; 1096 obj->symndx_gnu = hashtab[1]; 1097 nmaskwords = hashtab[2]; 1098 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1099 obj->maskwords_bm_gnu = nmaskwords - 1; 1100 obj->shift2_gnu = hashtab[3]; 1101 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1102 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1103 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1104 obj->symndx_gnu; 1105 /* Number of bitmask words is required to be power of 2 */ 1106 obj->valid_hash_gnu = powerof2(nmaskwords) && 1107 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1108 } 1109 break; 1110 1111 case DT_NEEDED: 1112 if (!obj->rtld) { 1113 Needed_Entry *nep = NEW(Needed_Entry); 1114 nep->name = dynp->d_un.d_val; 1115 nep->obj = NULL; 1116 nep->next = NULL; 1117 1118 *needed_tail = nep; 1119 needed_tail = &nep->next; 1120 } 1121 break; 1122 1123 case DT_FILTER: 1124 if (!obj->rtld) { 1125 Needed_Entry *nep = NEW(Needed_Entry); 1126 nep->name = dynp->d_un.d_val; 1127 nep->obj = NULL; 1128 nep->next = NULL; 1129 1130 *needed_filtees_tail = nep; 1131 needed_filtees_tail = &nep->next; 1132 } 1133 break; 1134 1135 case DT_AUXILIARY: 1136 if (!obj->rtld) { 1137 Needed_Entry *nep = NEW(Needed_Entry); 1138 nep->name = dynp->d_un.d_val; 1139 nep->obj = NULL; 1140 nep->next = NULL; 1141 1142 *needed_aux_filtees_tail = nep; 1143 needed_aux_filtees_tail = &nep->next; 1144 } 1145 break; 1146 1147 case DT_PLTGOT: 1148 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1149 break; 1150 1151 case DT_TEXTREL: 1152 obj->textrel = true; 1153 break; 1154 1155 case DT_SYMBOLIC: 1156 obj->symbolic = true; 1157 break; 1158 1159 case DT_RPATH: 1160 /* 1161 * We have to wait until later to process this, because we 1162 * might not have gotten the address of the string table yet. 1163 */ 1164 *dyn_rpath = dynp; 1165 break; 1166 1167 case DT_SONAME: 1168 *dyn_soname = dynp; 1169 break; 1170 1171 case DT_RUNPATH: 1172 *dyn_runpath = dynp; 1173 break; 1174 1175 case DT_INIT: 1176 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1177 break; 1178 1179 case DT_PREINIT_ARRAY: 1180 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1181 break; 1182 1183 case DT_PREINIT_ARRAYSZ: 1184 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1185 break; 1186 1187 case DT_INIT_ARRAY: 1188 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1189 break; 1190 1191 case DT_INIT_ARRAYSZ: 1192 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1193 break; 1194 1195 case DT_FINI: 1196 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1197 break; 1198 1199 case DT_FINI_ARRAY: 1200 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1201 break; 1202 1203 case DT_FINI_ARRAYSZ: 1204 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1205 break; 1206 1207 /* 1208 * Don't process DT_DEBUG on MIPS as the dynamic section 1209 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1210 */ 1211 1212 #ifndef __mips__ 1213 case DT_DEBUG: 1214 if (!early) 1215 dbg("Filling in DT_DEBUG entry"); 1216 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1217 break; 1218 #endif 1219 1220 case DT_FLAGS: 1221 if (dynp->d_un.d_val & DF_ORIGIN) 1222 obj->z_origin = true; 1223 if (dynp->d_un.d_val & DF_SYMBOLIC) 1224 obj->symbolic = true; 1225 if (dynp->d_un.d_val & DF_TEXTREL) 1226 obj->textrel = true; 1227 if (dynp->d_un.d_val & DF_BIND_NOW) 1228 obj->bind_now = true; 1229 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1230 ;*/ 1231 break; 1232 #ifdef __mips__ 1233 case DT_MIPS_LOCAL_GOTNO: 1234 obj->local_gotno = dynp->d_un.d_val; 1235 break; 1236 1237 case DT_MIPS_SYMTABNO: 1238 obj->symtabno = dynp->d_un.d_val; 1239 break; 1240 1241 case DT_MIPS_GOTSYM: 1242 obj->gotsym = dynp->d_un.d_val; 1243 break; 1244 1245 case DT_MIPS_RLD_MAP: 1246 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1247 break; 1248 1249 case DT_MIPS_PLTGOT: 1250 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1251 dynp->d_un.d_ptr); 1252 break; 1253 1254 #endif 1255 1256 #ifdef __powerpc64__ 1257 case DT_PPC64_GLINK: 1258 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1259 break; 1260 #endif 1261 1262 case DT_FLAGS_1: 1263 if (dynp->d_un.d_val & DF_1_NOOPEN) 1264 obj->z_noopen = true; 1265 if (dynp->d_un.d_val & DF_1_ORIGIN) 1266 obj->z_origin = true; 1267 if (dynp->d_un.d_val & DF_1_GLOBAL) 1268 obj->z_global = true; 1269 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1270 obj->bind_now = true; 1271 if (dynp->d_un.d_val & DF_1_NODELETE) 1272 obj->z_nodelete = true; 1273 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1274 obj->z_loadfltr = true; 1275 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1276 obj->z_interpose = true; 1277 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1278 obj->z_nodeflib = true; 1279 break; 1280 1281 default: 1282 if (!early) { 1283 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1284 (long)dynp->d_tag); 1285 } 1286 break; 1287 } 1288 } 1289 1290 obj->traced = false; 1291 1292 if (plttype == DT_RELA) { 1293 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1294 obj->pltrel = NULL; 1295 obj->pltrelasize = obj->pltrelsize; 1296 obj->pltrelsize = 0; 1297 } 1298 1299 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1300 if (obj->valid_hash_sysv) 1301 obj->dynsymcount = obj->nchains; 1302 else if (obj->valid_hash_gnu) { 1303 obj->dynsymcount = 0; 1304 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1305 if (obj->buckets_gnu[bkt] == 0) 1306 continue; 1307 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1308 do 1309 obj->dynsymcount++; 1310 while ((*hashval++ & 1u) == 0); 1311 } 1312 obj->dynsymcount += obj->symndx_gnu; 1313 } 1314 } 1315 1316 static bool 1317 obj_resolve_origin(Obj_Entry *obj) 1318 { 1319 1320 if (obj->origin_path != NULL) 1321 return (true); 1322 obj->origin_path = xmalloc(PATH_MAX); 1323 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1324 } 1325 1326 static void 1327 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1328 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1329 { 1330 1331 if (obj->z_origin && !obj_resolve_origin(obj)) 1332 rtld_die(); 1333 1334 if (dyn_runpath != NULL) { 1335 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1336 obj->runpath = origin_subst(obj, obj->runpath); 1337 } else if (dyn_rpath != NULL) { 1338 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1339 obj->rpath = origin_subst(obj, obj->rpath); 1340 } 1341 if (dyn_soname != NULL) 1342 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1343 } 1344 1345 static void 1346 digest_dynamic(Obj_Entry *obj, int early) 1347 { 1348 const Elf_Dyn *dyn_rpath; 1349 const Elf_Dyn *dyn_soname; 1350 const Elf_Dyn *dyn_runpath; 1351 1352 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1353 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1354 } 1355 1356 /* 1357 * Process a shared object's program header. This is used only for the 1358 * main program, when the kernel has already loaded the main program 1359 * into memory before calling the dynamic linker. It creates and 1360 * returns an Obj_Entry structure. 1361 */ 1362 static Obj_Entry * 1363 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1364 { 1365 Obj_Entry *obj; 1366 const Elf_Phdr *phlimit = phdr + phnum; 1367 const Elf_Phdr *ph; 1368 Elf_Addr note_start, note_end; 1369 int nsegs = 0; 1370 1371 obj = obj_new(); 1372 for (ph = phdr; ph < phlimit; ph++) { 1373 if (ph->p_type != PT_PHDR) 1374 continue; 1375 1376 obj->phdr = phdr; 1377 obj->phsize = ph->p_memsz; 1378 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1379 break; 1380 } 1381 1382 obj->stack_flags = PF_X | PF_R | PF_W; 1383 1384 for (ph = phdr; ph < phlimit; ph++) { 1385 switch (ph->p_type) { 1386 1387 case PT_INTERP: 1388 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1389 break; 1390 1391 case PT_LOAD: 1392 if (nsegs == 0) { /* First load segment */ 1393 obj->vaddrbase = trunc_page(ph->p_vaddr); 1394 obj->mapbase = obj->vaddrbase + obj->relocbase; 1395 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1396 obj->vaddrbase; 1397 } else { /* Last load segment */ 1398 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1399 obj->vaddrbase; 1400 } 1401 nsegs++; 1402 break; 1403 1404 case PT_DYNAMIC: 1405 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1406 break; 1407 1408 case PT_TLS: 1409 obj->tlsindex = 1; 1410 obj->tlssize = ph->p_memsz; 1411 obj->tlsalign = ph->p_align; 1412 obj->tlsinitsize = ph->p_filesz; 1413 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1414 break; 1415 1416 case PT_GNU_STACK: 1417 obj->stack_flags = ph->p_flags; 1418 break; 1419 1420 case PT_GNU_RELRO: 1421 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1422 obj->relro_size = round_page(ph->p_memsz); 1423 break; 1424 1425 case PT_NOTE: 1426 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1427 note_end = note_start + ph->p_filesz; 1428 digest_notes(obj, note_start, note_end); 1429 break; 1430 } 1431 } 1432 if (nsegs < 1) { 1433 _rtld_error("%s: too few PT_LOAD segments", path); 1434 return NULL; 1435 } 1436 1437 obj->entry = entry; 1438 return obj; 1439 } 1440 1441 void 1442 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1443 { 1444 const Elf_Note *note; 1445 const char *note_name; 1446 uintptr_t p; 1447 1448 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1449 note = (const Elf_Note *)((const char *)(note + 1) + 1450 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1451 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1452 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1453 note->n_descsz != sizeof(int32_t)) 1454 continue; 1455 if (note->n_type != NT_FREEBSD_ABI_TAG && 1456 note->n_type != NT_FREEBSD_NOINIT_TAG) 1457 continue; 1458 note_name = (const char *)(note + 1); 1459 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1460 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1461 continue; 1462 switch (note->n_type) { 1463 case NT_FREEBSD_ABI_TAG: 1464 /* FreeBSD osrel note */ 1465 p = (uintptr_t)(note + 1); 1466 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1467 obj->osrel = *(const int32_t *)(p); 1468 dbg("note osrel %d", obj->osrel); 1469 break; 1470 case NT_FREEBSD_NOINIT_TAG: 1471 /* FreeBSD 'crt does not call init' note */ 1472 obj->crt_no_init = true; 1473 dbg("note crt_no_init"); 1474 break; 1475 } 1476 } 1477 } 1478 1479 static Obj_Entry * 1480 dlcheck(void *handle) 1481 { 1482 Obj_Entry *obj; 1483 1484 TAILQ_FOREACH(obj, &obj_list, next) { 1485 if (obj == (Obj_Entry *) handle) 1486 break; 1487 } 1488 1489 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1490 _rtld_error("Invalid shared object handle %p", handle); 1491 return NULL; 1492 } 1493 return obj; 1494 } 1495 1496 /* 1497 * If the given object is already in the donelist, return true. Otherwise 1498 * add the object to the list and return false. 1499 */ 1500 static bool 1501 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1502 { 1503 unsigned int i; 1504 1505 for (i = 0; i < dlp->num_used; i++) 1506 if (dlp->objs[i] == obj) 1507 return true; 1508 /* 1509 * Our donelist allocation should always be sufficient. But if 1510 * our threads locking isn't working properly, more shared objects 1511 * could have been loaded since we allocated the list. That should 1512 * never happen, but we'll handle it properly just in case it does. 1513 */ 1514 if (dlp->num_used < dlp->num_alloc) 1515 dlp->objs[dlp->num_used++] = obj; 1516 return false; 1517 } 1518 1519 /* 1520 * Hash function for symbol table lookup. Don't even think about changing 1521 * this. It is specified by the System V ABI. 1522 */ 1523 unsigned long 1524 elf_hash(const char *name) 1525 { 1526 const unsigned char *p = (const unsigned char *) name; 1527 unsigned long h = 0; 1528 unsigned long g; 1529 1530 while (*p != '\0') { 1531 h = (h << 4) + *p++; 1532 if ((g = h & 0xf0000000) != 0) 1533 h ^= g >> 24; 1534 h &= ~g; 1535 } 1536 return h; 1537 } 1538 1539 /* 1540 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1541 * unsigned in case it's implemented with a wider type. 1542 */ 1543 static uint32_t 1544 gnu_hash(const char *s) 1545 { 1546 uint32_t h; 1547 unsigned char c; 1548 1549 h = 5381; 1550 for (c = *s; c != '\0'; c = *++s) 1551 h = h * 33 + c; 1552 return (h & 0xffffffff); 1553 } 1554 1555 1556 /* 1557 * Find the library with the given name, and return its full pathname. 1558 * The returned string is dynamically allocated. Generates an error 1559 * message and returns NULL if the library cannot be found. 1560 * 1561 * If the second argument is non-NULL, then it refers to an already- 1562 * loaded shared object, whose library search path will be searched. 1563 * 1564 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1565 * descriptor (which is close-on-exec) will be passed out via the third 1566 * argument. 1567 * 1568 * The search order is: 1569 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1570 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1571 * LD_LIBRARY_PATH 1572 * DT_RUNPATH in the referencing file 1573 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1574 * from list) 1575 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1576 * 1577 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1578 */ 1579 static char * 1580 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1581 { 1582 char *name, *pathname, *refobj_path; 1583 bool nodeflib, objgiven; 1584 1585 objgiven = refobj != NULL; 1586 1587 if (libmap_disable || !objgiven || 1588 (name = lm_find(refobj->path, xname)) == NULL) 1589 name = (char *)xname; 1590 1591 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1592 if (name[0] != '/' && !trust) { 1593 _rtld_error("Absolute pathname required " 1594 "for shared object \"%s\"", name); 1595 return (NULL); 1596 } 1597 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1598 __DECONST(char *, name))); 1599 } 1600 1601 dbg(" Searching for \"%s\"", name); 1602 refobj_path = objgiven ? refobj->path : NULL; 1603 1604 /* 1605 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1606 * back to pre-conforming behaviour if user requested so with 1607 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1608 * nodeflib. 1609 */ 1610 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1611 pathname = search_library_path(name, ld_library_path, 1612 refobj_path, fdp); 1613 if (pathname != NULL) 1614 return (pathname); 1615 if (refobj != NULL) { 1616 pathname = search_library_path(name, refobj->rpath, 1617 refobj_path, fdp); 1618 if (pathname != NULL) 1619 return (pathname); 1620 } 1621 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1622 if (pathname != NULL) 1623 return (pathname); 1624 pathname = search_library_path(name, gethints(false), 1625 refobj_path, fdp); 1626 if (pathname != NULL) 1627 return (pathname); 1628 pathname = search_library_path(name, ld_standard_library_path, 1629 refobj_path, fdp); 1630 if (pathname != NULL) 1631 return (pathname); 1632 } else { 1633 nodeflib = objgiven ? refobj->z_nodeflib : false; 1634 if (objgiven) { 1635 pathname = search_library_path(name, refobj->rpath, 1636 refobj->path, fdp); 1637 if (pathname != NULL) 1638 return (pathname); 1639 } 1640 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1641 pathname = search_library_path(name, obj_main->rpath, 1642 refobj_path, fdp); 1643 if (pathname != NULL) 1644 return (pathname); 1645 } 1646 pathname = search_library_path(name, ld_library_path, 1647 refobj_path, fdp); 1648 if (pathname != NULL) 1649 return (pathname); 1650 if (objgiven) { 1651 pathname = search_library_path(name, refobj->runpath, 1652 refobj_path, fdp); 1653 if (pathname != NULL) 1654 return (pathname); 1655 } 1656 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1657 if (pathname != NULL) 1658 return (pathname); 1659 pathname = search_library_path(name, gethints(nodeflib), 1660 refobj_path, fdp); 1661 if (pathname != NULL) 1662 return (pathname); 1663 if (objgiven && !nodeflib) { 1664 pathname = search_library_path(name, 1665 ld_standard_library_path, refobj_path, fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 } 1669 } 1670 1671 if (objgiven && refobj->path != NULL) { 1672 _rtld_error("Shared object \"%s\" not found, " 1673 "required by \"%s\"", name, basename(refobj->path)); 1674 } else { 1675 _rtld_error("Shared object \"%s\" not found", name); 1676 } 1677 return (NULL); 1678 } 1679 1680 /* 1681 * Given a symbol number in a referencing object, find the corresponding 1682 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1683 * no definition was found. Returns a pointer to the Obj_Entry of the 1684 * defining object via the reference parameter DEFOBJ_OUT. 1685 */ 1686 const Elf_Sym * 1687 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1688 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1689 RtldLockState *lockstate) 1690 { 1691 const Elf_Sym *ref; 1692 const Elf_Sym *def; 1693 const Obj_Entry *defobj; 1694 const Ver_Entry *ve; 1695 SymLook req; 1696 const char *name; 1697 int res; 1698 1699 /* 1700 * If we have already found this symbol, get the information from 1701 * the cache. 1702 */ 1703 if (symnum >= refobj->dynsymcount) 1704 return NULL; /* Bad object */ 1705 if (cache != NULL && cache[symnum].sym != NULL) { 1706 *defobj_out = cache[symnum].obj; 1707 return cache[symnum].sym; 1708 } 1709 1710 ref = refobj->symtab + symnum; 1711 name = refobj->strtab + ref->st_name; 1712 def = NULL; 1713 defobj = NULL; 1714 ve = NULL; 1715 1716 /* 1717 * We don't have to do a full scale lookup if the symbol is local. 1718 * We know it will bind to the instance in this load module; to 1719 * which we already have a pointer (ie ref). By not doing a lookup, 1720 * we not only improve performance, but it also avoids unresolvable 1721 * symbols when local symbols are not in the hash table. This has 1722 * been seen with the ia64 toolchain. 1723 */ 1724 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1725 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1726 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1727 symnum); 1728 } 1729 symlook_init(&req, name); 1730 req.flags = flags; 1731 ve = req.ventry = fetch_ventry(refobj, symnum); 1732 req.lockstate = lockstate; 1733 res = symlook_default(&req, refobj); 1734 if (res == 0) { 1735 def = req.sym_out; 1736 defobj = req.defobj_out; 1737 } 1738 } else { 1739 def = ref; 1740 defobj = refobj; 1741 } 1742 1743 /* 1744 * If we found no definition and the reference is weak, treat the 1745 * symbol as having the value zero. 1746 */ 1747 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1748 def = &sym_zero; 1749 defobj = obj_main; 1750 } 1751 1752 if (def != NULL) { 1753 *defobj_out = defobj; 1754 /* Record the information in the cache to avoid subsequent lookups. */ 1755 if (cache != NULL) { 1756 cache[symnum].sym = def; 1757 cache[symnum].obj = defobj; 1758 } 1759 } else { 1760 if (refobj != &obj_rtld) 1761 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1762 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1763 } 1764 return def; 1765 } 1766 1767 /* 1768 * Return the search path from the ldconfig hints file, reading it if 1769 * necessary. If nostdlib is true, then the default search paths are 1770 * not added to result. 1771 * 1772 * Returns NULL if there are problems with the hints file, 1773 * or if the search path there is empty. 1774 */ 1775 static const char * 1776 gethints(bool nostdlib) 1777 { 1778 static char *hints, *filtered_path; 1779 static struct elfhints_hdr hdr; 1780 struct fill_search_info_args sargs, hargs; 1781 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1782 struct dl_serpath *SLPpath, *hintpath; 1783 char *p; 1784 struct stat hint_stat; 1785 unsigned int SLPndx, hintndx, fndx, fcount; 1786 int fd; 1787 size_t flen; 1788 uint32_t dl; 1789 bool skip; 1790 1791 /* First call, read the hints file */ 1792 if (hints == NULL) { 1793 /* Keep from trying again in case the hints file is bad. */ 1794 hints = ""; 1795 1796 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1797 return (NULL); 1798 1799 /* 1800 * Check of hdr.dirlistlen value against type limit 1801 * intends to pacify static analyzers. Further 1802 * paranoia leads to checks that dirlist is fully 1803 * contained in the file range. 1804 */ 1805 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1806 hdr.magic != ELFHINTS_MAGIC || 1807 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1808 fstat(fd, &hint_stat) == -1) { 1809 cleanup1: 1810 close(fd); 1811 hdr.dirlistlen = 0; 1812 return (NULL); 1813 } 1814 dl = hdr.strtab; 1815 if (dl + hdr.dirlist < dl) 1816 goto cleanup1; 1817 dl += hdr.dirlist; 1818 if (dl + hdr.dirlistlen < dl) 1819 goto cleanup1; 1820 dl += hdr.dirlistlen; 1821 if (dl > hint_stat.st_size) 1822 goto cleanup1; 1823 p = xmalloc(hdr.dirlistlen + 1); 1824 if (pread(fd, p, hdr.dirlistlen + 1, 1825 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1826 p[hdr.dirlistlen] != '\0') { 1827 free(p); 1828 goto cleanup1; 1829 } 1830 hints = p; 1831 close(fd); 1832 } 1833 1834 /* 1835 * If caller agreed to receive list which includes the default 1836 * paths, we are done. Otherwise, if we still did not 1837 * calculated filtered result, do it now. 1838 */ 1839 if (!nostdlib) 1840 return (hints[0] != '\0' ? hints : NULL); 1841 if (filtered_path != NULL) 1842 goto filt_ret; 1843 1844 /* 1845 * Obtain the list of all configured search paths, and the 1846 * list of the default paths. 1847 * 1848 * First estimate the size of the results. 1849 */ 1850 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1851 smeta.dls_cnt = 0; 1852 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1853 hmeta.dls_cnt = 0; 1854 1855 sargs.request = RTLD_DI_SERINFOSIZE; 1856 sargs.serinfo = &smeta; 1857 hargs.request = RTLD_DI_SERINFOSIZE; 1858 hargs.serinfo = &hmeta; 1859 1860 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1861 &sargs); 1862 path_enumerate(hints, fill_search_info, NULL, &hargs); 1863 1864 SLPinfo = xmalloc(smeta.dls_size); 1865 hintinfo = xmalloc(hmeta.dls_size); 1866 1867 /* 1868 * Next fetch both sets of paths. 1869 */ 1870 sargs.request = RTLD_DI_SERINFO; 1871 sargs.serinfo = SLPinfo; 1872 sargs.serpath = &SLPinfo->dls_serpath[0]; 1873 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1874 1875 hargs.request = RTLD_DI_SERINFO; 1876 hargs.serinfo = hintinfo; 1877 hargs.serpath = &hintinfo->dls_serpath[0]; 1878 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1879 1880 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1881 &sargs); 1882 path_enumerate(hints, fill_search_info, NULL, &hargs); 1883 1884 /* 1885 * Now calculate the difference between two sets, by excluding 1886 * standard paths from the full set. 1887 */ 1888 fndx = 0; 1889 fcount = 0; 1890 filtered_path = xmalloc(hdr.dirlistlen + 1); 1891 hintpath = &hintinfo->dls_serpath[0]; 1892 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1893 skip = false; 1894 SLPpath = &SLPinfo->dls_serpath[0]; 1895 /* 1896 * Check each standard path against current. 1897 */ 1898 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1899 /* matched, skip the path */ 1900 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1901 skip = true; 1902 break; 1903 } 1904 } 1905 if (skip) 1906 continue; 1907 /* 1908 * Not matched against any standard path, add the path 1909 * to result. Separate consequtive paths with ':'. 1910 */ 1911 if (fcount > 0) { 1912 filtered_path[fndx] = ':'; 1913 fndx++; 1914 } 1915 fcount++; 1916 flen = strlen(hintpath->dls_name); 1917 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1918 fndx += flen; 1919 } 1920 filtered_path[fndx] = '\0'; 1921 1922 free(SLPinfo); 1923 free(hintinfo); 1924 1925 filt_ret: 1926 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1927 } 1928 1929 static void 1930 init_dag(Obj_Entry *root) 1931 { 1932 const Needed_Entry *needed; 1933 const Objlist_Entry *elm; 1934 DoneList donelist; 1935 1936 if (root->dag_inited) 1937 return; 1938 donelist_init(&donelist); 1939 1940 /* Root object belongs to own DAG. */ 1941 objlist_push_tail(&root->dldags, root); 1942 objlist_push_tail(&root->dagmembers, root); 1943 donelist_check(&donelist, root); 1944 1945 /* 1946 * Add dependencies of root object to DAG in breadth order 1947 * by exploiting the fact that each new object get added 1948 * to the tail of the dagmembers list. 1949 */ 1950 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1951 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1952 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1953 continue; 1954 objlist_push_tail(&needed->obj->dldags, root); 1955 objlist_push_tail(&root->dagmembers, needed->obj); 1956 } 1957 } 1958 root->dag_inited = true; 1959 } 1960 1961 static void 1962 init_marker(Obj_Entry *marker) 1963 { 1964 1965 bzero(marker, sizeof(*marker)); 1966 marker->marker = true; 1967 } 1968 1969 Obj_Entry * 1970 globallist_curr(const Obj_Entry *obj) 1971 { 1972 1973 for (;;) { 1974 if (obj == NULL) 1975 return (NULL); 1976 if (!obj->marker) 1977 return (__DECONST(Obj_Entry *, obj)); 1978 obj = TAILQ_PREV(obj, obj_entry_q, next); 1979 } 1980 } 1981 1982 Obj_Entry * 1983 globallist_next(const Obj_Entry *obj) 1984 { 1985 1986 for (;;) { 1987 obj = TAILQ_NEXT(obj, next); 1988 if (obj == NULL) 1989 return (NULL); 1990 if (!obj->marker) 1991 return (__DECONST(Obj_Entry *, obj)); 1992 } 1993 } 1994 1995 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1996 static void 1997 hold_object(Obj_Entry *obj) 1998 { 1999 2000 obj->holdcount++; 2001 } 2002 2003 static void 2004 unhold_object(Obj_Entry *obj) 2005 { 2006 2007 assert(obj->holdcount > 0); 2008 if (--obj->holdcount == 0 && obj->unholdfree) 2009 release_object(obj); 2010 } 2011 2012 static void 2013 process_z(Obj_Entry *root) 2014 { 2015 const Objlist_Entry *elm; 2016 Obj_Entry *obj; 2017 2018 /* 2019 * Walk over object DAG and process every dependent object 2020 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2021 * to grow their own DAG. 2022 * 2023 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2024 * symlook_global() to work. 2025 * 2026 * For DF_1_NODELETE, the DAG should have its reference upped. 2027 */ 2028 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2029 obj = elm->obj; 2030 if (obj == NULL) 2031 continue; 2032 if (obj->z_nodelete && !obj->ref_nodel) { 2033 dbg("obj %s -z nodelete", obj->path); 2034 init_dag(obj); 2035 ref_dag(obj); 2036 obj->ref_nodel = true; 2037 } 2038 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2039 dbg("obj %s -z global", obj->path); 2040 objlist_push_tail(&list_global, obj); 2041 init_dag(obj); 2042 } 2043 } 2044 } 2045 /* 2046 * Initialize the dynamic linker. The argument is the address at which 2047 * the dynamic linker has been mapped into memory. The primary task of 2048 * this function is to relocate the dynamic linker. 2049 */ 2050 static void 2051 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2052 { 2053 Obj_Entry objtmp; /* Temporary rtld object */ 2054 const Elf_Ehdr *ehdr; 2055 const Elf_Dyn *dyn_rpath; 2056 const Elf_Dyn *dyn_soname; 2057 const Elf_Dyn *dyn_runpath; 2058 2059 #ifdef RTLD_INIT_PAGESIZES_EARLY 2060 /* The page size is required by the dynamic memory allocator. */ 2061 init_pagesizes(aux_info); 2062 #endif 2063 2064 /* 2065 * Conjure up an Obj_Entry structure for the dynamic linker. 2066 * 2067 * The "path" member can't be initialized yet because string constants 2068 * cannot yet be accessed. Below we will set it correctly. 2069 */ 2070 memset(&objtmp, 0, sizeof(objtmp)); 2071 objtmp.path = NULL; 2072 objtmp.rtld = true; 2073 objtmp.mapbase = mapbase; 2074 #ifdef PIC 2075 objtmp.relocbase = mapbase; 2076 #endif 2077 2078 objtmp.dynamic = rtld_dynamic(&objtmp); 2079 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2080 assert(objtmp.needed == NULL); 2081 #if !defined(__mips__) 2082 /* MIPS has a bogus DT_TEXTREL. */ 2083 assert(!objtmp.textrel); 2084 #endif 2085 /* 2086 * Temporarily put the dynamic linker entry into the object list, so 2087 * that symbols can be found. 2088 */ 2089 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2090 2091 ehdr = (Elf_Ehdr *)mapbase; 2092 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2093 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2094 2095 /* Initialize the object list. */ 2096 TAILQ_INIT(&obj_list); 2097 2098 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2099 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2100 2101 #ifndef RTLD_INIT_PAGESIZES_EARLY 2102 /* The page size is required by the dynamic memory allocator. */ 2103 init_pagesizes(aux_info); 2104 #endif 2105 2106 if (aux_info[AT_OSRELDATE] != NULL) 2107 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2108 2109 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2110 2111 /* Replace the path with a dynamically allocated copy. */ 2112 obj_rtld.path = xstrdup(ld_path_rtld); 2113 2114 r_debug.r_brk = r_debug_state; 2115 r_debug.r_state = RT_CONSISTENT; 2116 } 2117 2118 /* 2119 * Retrieve the array of supported page sizes. The kernel provides the page 2120 * sizes in increasing order. 2121 */ 2122 static void 2123 init_pagesizes(Elf_Auxinfo **aux_info) 2124 { 2125 static size_t psa[MAXPAGESIZES]; 2126 int mib[2]; 2127 size_t len, size; 2128 2129 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2130 NULL) { 2131 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2132 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2133 } else { 2134 len = 2; 2135 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2136 size = sizeof(psa); 2137 else { 2138 /* As a fallback, retrieve the base page size. */ 2139 size = sizeof(psa[0]); 2140 if (aux_info[AT_PAGESZ] != NULL) { 2141 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2142 goto psa_filled; 2143 } else { 2144 mib[0] = CTL_HW; 2145 mib[1] = HW_PAGESIZE; 2146 len = 2; 2147 } 2148 } 2149 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2150 _rtld_error("sysctl for hw.pagesize(s) failed"); 2151 rtld_die(); 2152 } 2153 psa_filled: 2154 pagesizes = psa; 2155 } 2156 npagesizes = size / sizeof(pagesizes[0]); 2157 /* Discard any invalid entries at the end of the array. */ 2158 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2159 npagesizes--; 2160 } 2161 2162 /* 2163 * Add the init functions from a needed object list (and its recursive 2164 * needed objects) to "list". This is not used directly; it is a helper 2165 * function for initlist_add_objects(). The write lock must be held 2166 * when this function is called. 2167 */ 2168 static void 2169 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2170 { 2171 /* Recursively process the successor needed objects. */ 2172 if (needed->next != NULL) 2173 initlist_add_neededs(needed->next, list); 2174 2175 /* Process the current needed object. */ 2176 if (needed->obj != NULL) 2177 initlist_add_objects(needed->obj, needed->obj, list); 2178 } 2179 2180 /* 2181 * Scan all of the DAGs rooted in the range of objects from "obj" to 2182 * "tail" and add their init functions to "list". This recurses over 2183 * the DAGs and ensure the proper init ordering such that each object's 2184 * needed libraries are initialized before the object itself. At the 2185 * same time, this function adds the objects to the global finalization 2186 * list "list_fini" in the opposite order. The write lock must be 2187 * held when this function is called. 2188 */ 2189 static void 2190 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2191 { 2192 Obj_Entry *nobj; 2193 2194 if (obj->init_scanned || obj->init_done) 2195 return; 2196 obj->init_scanned = true; 2197 2198 /* Recursively process the successor objects. */ 2199 nobj = globallist_next(obj); 2200 if (nobj != NULL && obj != tail) 2201 initlist_add_objects(nobj, tail, list); 2202 2203 /* Recursively process the needed objects. */ 2204 if (obj->needed != NULL) 2205 initlist_add_neededs(obj->needed, list); 2206 if (obj->needed_filtees != NULL) 2207 initlist_add_neededs(obj->needed_filtees, list); 2208 if (obj->needed_aux_filtees != NULL) 2209 initlist_add_neededs(obj->needed_aux_filtees, list); 2210 2211 /* Add the object to the init list. */ 2212 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2213 obj->init_array != (Elf_Addr)NULL) 2214 objlist_push_tail(list, obj); 2215 2216 /* Add the object to the global fini list in the reverse order. */ 2217 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2218 && !obj->on_fini_list) { 2219 objlist_push_head(&list_fini, obj); 2220 obj->on_fini_list = true; 2221 } 2222 } 2223 2224 #ifndef FPTR_TARGET 2225 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2226 #endif 2227 2228 static void 2229 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2230 { 2231 Needed_Entry *needed, *needed1; 2232 2233 for (needed = n; needed != NULL; needed = needed->next) { 2234 if (needed->obj != NULL) { 2235 dlclose_locked(needed->obj, lockstate); 2236 needed->obj = NULL; 2237 } 2238 } 2239 for (needed = n; needed != NULL; needed = needed1) { 2240 needed1 = needed->next; 2241 free(needed); 2242 } 2243 } 2244 2245 static void 2246 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2247 { 2248 2249 free_needed_filtees(obj->needed_filtees, lockstate); 2250 obj->needed_filtees = NULL; 2251 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2252 obj->needed_aux_filtees = NULL; 2253 obj->filtees_loaded = false; 2254 } 2255 2256 static void 2257 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2258 RtldLockState *lockstate) 2259 { 2260 2261 for (; needed != NULL; needed = needed->next) { 2262 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2263 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2264 RTLD_LOCAL, lockstate); 2265 } 2266 } 2267 2268 static void 2269 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2270 { 2271 2272 lock_restart_for_upgrade(lockstate); 2273 if (!obj->filtees_loaded) { 2274 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2275 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2276 obj->filtees_loaded = true; 2277 } 2278 } 2279 2280 static int 2281 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2282 { 2283 Obj_Entry *obj1; 2284 2285 for (; needed != NULL; needed = needed->next) { 2286 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2287 flags & ~RTLD_LO_NOLOAD); 2288 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2289 return (-1); 2290 } 2291 return (0); 2292 } 2293 2294 /* 2295 * Given a shared object, traverse its list of needed objects, and load 2296 * each of them. Returns 0 on success. Generates an error message and 2297 * returns -1 on failure. 2298 */ 2299 static int 2300 load_needed_objects(Obj_Entry *first, int flags) 2301 { 2302 Obj_Entry *obj; 2303 2304 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2305 if (obj->marker) 2306 continue; 2307 if (process_needed(obj, obj->needed, flags) == -1) 2308 return (-1); 2309 } 2310 return (0); 2311 } 2312 2313 static int 2314 load_preload_objects(void) 2315 { 2316 char *p = ld_preload; 2317 Obj_Entry *obj; 2318 static const char delim[] = " \t:;"; 2319 2320 if (p == NULL) 2321 return 0; 2322 2323 p += strspn(p, delim); 2324 while (*p != '\0') { 2325 size_t len = strcspn(p, delim); 2326 char savech; 2327 2328 savech = p[len]; 2329 p[len] = '\0'; 2330 obj = load_object(p, -1, NULL, 0); 2331 if (obj == NULL) 2332 return -1; /* XXX - cleanup */ 2333 obj->z_interpose = true; 2334 p[len] = savech; 2335 p += len; 2336 p += strspn(p, delim); 2337 } 2338 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2339 return 0; 2340 } 2341 2342 static const char * 2343 printable_path(const char *path) 2344 { 2345 2346 return (path == NULL ? "<unknown>" : path); 2347 } 2348 2349 /* 2350 * Load a shared object into memory, if it is not already loaded. The 2351 * object may be specified by name or by user-supplied file descriptor 2352 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2353 * duplicate is. 2354 * 2355 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2356 * on failure. 2357 */ 2358 static Obj_Entry * 2359 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2360 { 2361 Obj_Entry *obj; 2362 int fd; 2363 struct stat sb; 2364 char *path; 2365 2366 fd = -1; 2367 if (name != NULL) { 2368 TAILQ_FOREACH(obj, &obj_list, next) { 2369 if (obj->marker || obj->doomed) 2370 continue; 2371 if (object_match_name(obj, name)) 2372 return (obj); 2373 } 2374 2375 path = find_library(name, refobj, &fd); 2376 if (path == NULL) 2377 return (NULL); 2378 } else 2379 path = NULL; 2380 2381 if (fd >= 0) { 2382 /* 2383 * search_library_pathfds() opens a fresh file descriptor for the 2384 * library, so there is no need to dup(). 2385 */ 2386 } else if (fd_u == -1) { 2387 /* 2388 * If we didn't find a match by pathname, or the name is not 2389 * supplied, open the file and check again by device and inode. 2390 * This avoids false mismatches caused by multiple links or ".." 2391 * in pathnames. 2392 * 2393 * To avoid a race, we open the file and use fstat() rather than 2394 * using stat(). 2395 */ 2396 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2397 _rtld_error("Cannot open \"%s\"", path); 2398 free(path); 2399 return (NULL); 2400 } 2401 } else { 2402 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2403 if (fd == -1) { 2404 _rtld_error("Cannot dup fd"); 2405 free(path); 2406 return (NULL); 2407 } 2408 } 2409 if (fstat(fd, &sb) == -1) { 2410 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2411 close(fd); 2412 free(path); 2413 return NULL; 2414 } 2415 TAILQ_FOREACH(obj, &obj_list, next) { 2416 if (obj->marker || obj->doomed) 2417 continue; 2418 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2419 break; 2420 } 2421 if (obj != NULL && name != NULL) { 2422 object_add_name(obj, name); 2423 free(path); 2424 close(fd); 2425 return obj; 2426 } 2427 if (flags & RTLD_LO_NOLOAD) { 2428 free(path); 2429 close(fd); 2430 return (NULL); 2431 } 2432 2433 /* First use of this object, so we must map it in */ 2434 obj = do_load_object(fd, name, path, &sb, flags); 2435 if (obj == NULL) 2436 free(path); 2437 close(fd); 2438 2439 return obj; 2440 } 2441 2442 static Obj_Entry * 2443 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2444 int flags) 2445 { 2446 Obj_Entry *obj; 2447 struct statfs fs; 2448 2449 /* 2450 * but first, make sure that environment variables haven't been 2451 * used to circumvent the noexec flag on a filesystem. 2452 */ 2453 if (dangerous_ld_env) { 2454 if (fstatfs(fd, &fs) != 0) { 2455 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2456 return NULL; 2457 } 2458 if (fs.f_flags & MNT_NOEXEC) { 2459 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2460 return NULL; 2461 } 2462 } 2463 dbg("loading \"%s\"", printable_path(path)); 2464 obj = map_object(fd, printable_path(path), sbp); 2465 if (obj == NULL) 2466 return NULL; 2467 2468 /* 2469 * If DT_SONAME is present in the object, digest_dynamic2 already 2470 * added it to the object names. 2471 */ 2472 if (name != NULL) 2473 object_add_name(obj, name); 2474 obj->path = path; 2475 digest_dynamic(obj, 0); 2476 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2477 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2478 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2479 RTLD_LO_DLOPEN) { 2480 dbg("refusing to load non-loadable \"%s\"", obj->path); 2481 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2482 munmap(obj->mapbase, obj->mapsize); 2483 obj_free(obj); 2484 return (NULL); 2485 } 2486 2487 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2488 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2489 obj_count++; 2490 obj_loads++; 2491 linkmap_add(obj); /* for GDB & dlinfo() */ 2492 max_stack_flags |= obj->stack_flags; 2493 2494 dbg(" %p .. %p: %s", obj->mapbase, 2495 obj->mapbase + obj->mapsize - 1, obj->path); 2496 if (obj->textrel) 2497 dbg(" WARNING: %s has impure text", obj->path); 2498 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2499 obj->path); 2500 2501 return obj; 2502 } 2503 2504 static Obj_Entry * 2505 obj_from_addr(const void *addr) 2506 { 2507 Obj_Entry *obj; 2508 2509 TAILQ_FOREACH(obj, &obj_list, next) { 2510 if (obj->marker) 2511 continue; 2512 if (addr < (void *) obj->mapbase) 2513 continue; 2514 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2515 return obj; 2516 } 2517 return NULL; 2518 } 2519 2520 static void 2521 preinit_main(void) 2522 { 2523 Elf_Addr *preinit_addr; 2524 int index; 2525 2526 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2527 if (preinit_addr == NULL) 2528 return; 2529 2530 for (index = 0; index < obj_main->preinit_array_num; index++) { 2531 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2532 dbg("calling preinit function for %s at %p", obj_main->path, 2533 (void *)preinit_addr[index]); 2534 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2535 0, 0, obj_main->path); 2536 call_init_pointer(obj_main, preinit_addr[index]); 2537 } 2538 } 2539 } 2540 2541 /* 2542 * Call the finalization functions for each of the objects in "list" 2543 * belonging to the DAG of "root" and referenced once. If NULL "root" 2544 * is specified, every finalization function will be called regardless 2545 * of the reference count and the list elements won't be freed. All of 2546 * the objects are expected to have non-NULL fini functions. 2547 */ 2548 static void 2549 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2550 { 2551 Objlist_Entry *elm; 2552 char *saved_msg; 2553 Elf_Addr *fini_addr; 2554 int index; 2555 2556 assert(root == NULL || root->refcount == 1); 2557 2558 if (root != NULL) 2559 root->doomed = true; 2560 2561 /* 2562 * Preserve the current error message since a fini function might 2563 * call into the dynamic linker and overwrite it. 2564 */ 2565 saved_msg = errmsg_save(); 2566 do { 2567 STAILQ_FOREACH(elm, list, link) { 2568 if (root != NULL && (elm->obj->refcount != 1 || 2569 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2570 continue; 2571 /* Remove object from fini list to prevent recursive invocation. */ 2572 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2573 /* Ensure that new references cannot be acquired. */ 2574 elm->obj->doomed = true; 2575 2576 hold_object(elm->obj); 2577 lock_release(rtld_bind_lock, lockstate); 2578 /* 2579 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2580 * When this happens, DT_FINI_ARRAY is processed first. 2581 */ 2582 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2583 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2584 for (index = elm->obj->fini_array_num - 1; index >= 0; 2585 index--) { 2586 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2587 dbg("calling fini function for %s at %p", 2588 elm->obj->path, (void *)fini_addr[index]); 2589 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2590 (void *)fini_addr[index], 0, 0, elm->obj->path); 2591 call_initfini_pointer(elm->obj, fini_addr[index]); 2592 } 2593 } 2594 } 2595 if (elm->obj->fini != (Elf_Addr)NULL) { 2596 dbg("calling fini function for %s at %p", elm->obj->path, 2597 (void *)elm->obj->fini); 2598 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2599 0, 0, elm->obj->path); 2600 call_initfini_pointer(elm->obj, elm->obj->fini); 2601 } 2602 wlock_acquire(rtld_bind_lock, lockstate); 2603 unhold_object(elm->obj); 2604 /* No need to free anything if process is going down. */ 2605 if (root != NULL) 2606 free(elm); 2607 /* 2608 * We must restart the list traversal after every fini call 2609 * because a dlclose() call from the fini function or from 2610 * another thread might have modified the reference counts. 2611 */ 2612 break; 2613 } 2614 } while (elm != NULL); 2615 errmsg_restore(saved_msg); 2616 } 2617 2618 /* 2619 * Call the initialization functions for each of the objects in 2620 * "list". All of the objects are expected to have non-NULL init 2621 * functions. 2622 */ 2623 static void 2624 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2625 { 2626 Objlist_Entry *elm; 2627 Obj_Entry *obj; 2628 char *saved_msg; 2629 Elf_Addr *init_addr; 2630 int index; 2631 2632 /* 2633 * Clean init_scanned flag so that objects can be rechecked and 2634 * possibly initialized earlier if any of vectors called below 2635 * cause the change by using dlopen. 2636 */ 2637 TAILQ_FOREACH(obj, &obj_list, next) { 2638 if (obj->marker) 2639 continue; 2640 obj->init_scanned = false; 2641 } 2642 2643 /* 2644 * Preserve the current error message since an init function might 2645 * call into the dynamic linker and overwrite it. 2646 */ 2647 saved_msg = errmsg_save(); 2648 STAILQ_FOREACH(elm, list, link) { 2649 if (elm->obj->init_done) /* Initialized early. */ 2650 continue; 2651 /* 2652 * Race: other thread might try to use this object before current 2653 * one completes the initialization. Not much can be done here 2654 * without better locking. 2655 */ 2656 elm->obj->init_done = true; 2657 hold_object(elm->obj); 2658 lock_release(rtld_bind_lock, lockstate); 2659 2660 /* 2661 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2662 * When this happens, DT_INIT is processed first. 2663 */ 2664 if (elm->obj->init != (Elf_Addr)NULL) { 2665 dbg("calling init function for %s at %p", elm->obj->path, 2666 (void *)elm->obj->init); 2667 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2668 0, 0, elm->obj->path); 2669 call_initfini_pointer(elm->obj, elm->obj->init); 2670 } 2671 init_addr = (Elf_Addr *)elm->obj->init_array; 2672 if (init_addr != NULL) { 2673 for (index = 0; index < elm->obj->init_array_num; index++) { 2674 if (init_addr[index] != 0 && init_addr[index] != 1) { 2675 dbg("calling init function for %s at %p", elm->obj->path, 2676 (void *)init_addr[index]); 2677 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2678 (void *)init_addr[index], 0, 0, elm->obj->path); 2679 call_init_pointer(elm->obj, init_addr[index]); 2680 } 2681 } 2682 } 2683 wlock_acquire(rtld_bind_lock, lockstate); 2684 unhold_object(elm->obj); 2685 } 2686 errmsg_restore(saved_msg); 2687 } 2688 2689 static void 2690 objlist_clear(Objlist *list) 2691 { 2692 Objlist_Entry *elm; 2693 2694 while (!STAILQ_EMPTY(list)) { 2695 elm = STAILQ_FIRST(list); 2696 STAILQ_REMOVE_HEAD(list, link); 2697 free(elm); 2698 } 2699 } 2700 2701 static Objlist_Entry * 2702 objlist_find(Objlist *list, const Obj_Entry *obj) 2703 { 2704 Objlist_Entry *elm; 2705 2706 STAILQ_FOREACH(elm, list, link) 2707 if (elm->obj == obj) 2708 return elm; 2709 return NULL; 2710 } 2711 2712 static void 2713 objlist_init(Objlist *list) 2714 { 2715 STAILQ_INIT(list); 2716 } 2717 2718 static void 2719 objlist_push_head(Objlist *list, Obj_Entry *obj) 2720 { 2721 Objlist_Entry *elm; 2722 2723 elm = NEW(Objlist_Entry); 2724 elm->obj = obj; 2725 STAILQ_INSERT_HEAD(list, elm, link); 2726 } 2727 2728 static void 2729 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2730 { 2731 Objlist_Entry *elm; 2732 2733 elm = NEW(Objlist_Entry); 2734 elm->obj = obj; 2735 STAILQ_INSERT_TAIL(list, elm, link); 2736 } 2737 2738 static void 2739 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2740 { 2741 Objlist_Entry *elm, *listelm; 2742 2743 STAILQ_FOREACH(listelm, list, link) { 2744 if (listelm->obj == listobj) 2745 break; 2746 } 2747 elm = NEW(Objlist_Entry); 2748 elm->obj = obj; 2749 if (listelm != NULL) 2750 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2751 else 2752 STAILQ_INSERT_TAIL(list, elm, link); 2753 } 2754 2755 static void 2756 objlist_remove(Objlist *list, Obj_Entry *obj) 2757 { 2758 Objlist_Entry *elm; 2759 2760 if ((elm = objlist_find(list, obj)) != NULL) { 2761 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2762 free(elm); 2763 } 2764 } 2765 2766 /* 2767 * Relocate dag rooted in the specified object. 2768 * Returns 0 on success, or -1 on failure. 2769 */ 2770 2771 static int 2772 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2773 int flags, RtldLockState *lockstate) 2774 { 2775 Objlist_Entry *elm; 2776 int error; 2777 2778 error = 0; 2779 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2780 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2781 lockstate); 2782 if (error == -1) 2783 break; 2784 } 2785 return (error); 2786 } 2787 2788 /* 2789 * Prepare for, or clean after, relocating an object marked with 2790 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2791 * segments are remapped read-write. After relocations are done, the 2792 * segment's permissions are returned back to the modes specified in 2793 * the phdrs. If any relocation happened, or always for wired 2794 * program, COW is triggered. 2795 */ 2796 static int 2797 reloc_textrel_prot(Obj_Entry *obj, bool before) 2798 { 2799 const Elf_Phdr *ph; 2800 void *base; 2801 size_t l, sz; 2802 int prot; 2803 2804 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2805 l--, ph++) { 2806 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2807 continue; 2808 base = obj->relocbase + trunc_page(ph->p_vaddr); 2809 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2810 trunc_page(ph->p_vaddr); 2811 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2812 if (mprotect(base, sz, prot) == -1) { 2813 _rtld_error("%s: Cannot write-%sable text segment: %s", 2814 obj->path, before ? "en" : "dis", 2815 rtld_strerror(errno)); 2816 return (-1); 2817 } 2818 } 2819 return (0); 2820 } 2821 2822 /* 2823 * Relocate single object. 2824 * Returns 0 on success, or -1 on failure. 2825 */ 2826 static int 2827 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2828 int flags, RtldLockState *lockstate) 2829 { 2830 2831 if (obj->relocated) 2832 return (0); 2833 obj->relocated = true; 2834 if (obj != rtldobj) 2835 dbg("relocating \"%s\"", obj->path); 2836 2837 if (obj->symtab == NULL || obj->strtab == NULL || 2838 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2839 _rtld_error("%s: Shared object has no run-time symbol table", 2840 obj->path); 2841 return (-1); 2842 } 2843 2844 /* There are relocations to the write-protected text segment. */ 2845 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2846 return (-1); 2847 2848 /* Process the non-PLT non-IFUNC relocations. */ 2849 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2850 return (-1); 2851 2852 /* Re-protected the text segment. */ 2853 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2854 return (-1); 2855 2856 /* Set the special PLT or GOT entries. */ 2857 init_pltgot(obj); 2858 2859 /* Process the PLT relocations. */ 2860 if (reloc_plt(obj) == -1) 2861 return (-1); 2862 /* Relocate the jump slots if we are doing immediate binding. */ 2863 if (obj->bind_now || bind_now) { 2864 if (reloc_jmpslots(obj, flags, lockstate) == -1 || 2865 resolve_object_ifunc(obj, true, flags, lockstate) == -1) 2866 return (-1); 2867 } 2868 2869 /* 2870 * Process the non-PLT IFUNC relocations. The relocations are 2871 * processed in two phases, because IFUNC resolvers may 2872 * reference other symbols, which must be readily processed 2873 * before resolvers are called. 2874 */ 2875 if (obj->non_plt_gnu_ifunc && 2876 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2877 return (-1); 2878 2879 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2880 return (-1); 2881 2882 /* 2883 * Set up the magic number and version in the Obj_Entry. These 2884 * were checked in the crt1.o from the original ElfKit, so we 2885 * set them for backward compatibility. 2886 */ 2887 obj->magic = RTLD_MAGIC; 2888 obj->version = RTLD_VERSION; 2889 2890 return (0); 2891 } 2892 2893 /* 2894 * Relocate newly-loaded shared objects. The argument is a pointer to 2895 * the Obj_Entry for the first such object. All objects from the first 2896 * to the end of the list of objects are relocated. Returns 0 on success, 2897 * or -1 on failure. 2898 */ 2899 static int 2900 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2901 int flags, RtldLockState *lockstate) 2902 { 2903 Obj_Entry *obj; 2904 int error; 2905 2906 for (error = 0, obj = first; obj != NULL; 2907 obj = TAILQ_NEXT(obj, next)) { 2908 if (obj->marker) 2909 continue; 2910 error = relocate_object(obj, bind_now, rtldobj, flags, 2911 lockstate); 2912 if (error == -1) 2913 break; 2914 } 2915 return (error); 2916 } 2917 2918 /* 2919 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2920 * referencing STT_GNU_IFUNC symbols is postponed till the other 2921 * relocations are done. The indirect functions specified as 2922 * ifunc are allowed to call other symbols, so we need to have 2923 * objects relocated before asking for resolution from indirects. 2924 * 2925 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2926 * instead of the usual lazy handling of PLT slots. It is 2927 * consistent with how GNU does it. 2928 */ 2929 static int 2930 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2931 RtldLockState *lockstate) 2932 { 2933 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2934 return (-1); 2935 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2936 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2937 return (-1); 2938 return (0); 2939 } 2940 2941 static int 2942 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2943 RtldLockState *lockstate) 2944 { 2945 Obj_Entry *obj; 2946 2947 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2948 if (obj->marker) 2949 continue; 2950 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2951 return (-1); 2952 } 2953 return (0); 2954 } 2955 2956 static int 2957 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2958 RtldLockState *lockstate) 2959 { 2960 Objlist_Entry *elm; 2961 2962 STAILQ_FOREACH(elm, list, link) { 2963 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2964 lockstate) == -1) 2965 return (-1); 2966 } 2967 return (0); 2968 } 2969 2970 /* 2971 * Cleanup procedure. It will be called (by the atexit mechanism) just 2972 * before the process exits. 2973 */ 2974 static void 2975 rtld_exit(void) 2976 { 2977 RtldLockState lockstate; 2978 2979 wlock_acquire(rtld_bind_lock, &lockstate); 2980 dbg("rtld_exit()"); 2981 objlist_call_fini(&list_fini, NULL, &lockstate); 2982 /* No need to remove the items from the list, since we are exiting. */ 2983 if (!libmap_disable) 2984 lm_fini(); 2985 lock_release(rtld_bind_lock, &lockstate); 2986 } 2987 2988 /* 2989 * Iterate over a search path, translate each element, and invoke the 2990 * callback on the result. 2991 */ 2992 static void * 2993 path_enumerate(const char *path, path_enum_proc callback, 2994 const char *refobj_path, void *arg) 2995 { 2996 const char *trans; 2997 if (path == NULL) 2998 return (NULL); 2999 3000 path += strspn(path, ":;"); 3001 while (*path != '\0') { 3002 size_t len; 3003 char *res; 3004 3005 len = strcspn(path, ":;"); 3006 trans = lm_findn(refobj_path, path, len); 3007 if (trans) 3008 res = callback(trans, strlen(trans), arg); 3009 else 3010 res = callback(path, len, arg); 3011 3012 if (res != NULL) 3013 return (res); 3014 3015 path += len; 3016 path += strspn(path, ":;"); 3017 } 3018 3019 return (NULL); 3020 } 3021 3022 struct try_library_args { 3023 const char *name; 3024 size_t namelen; 3025 char *buffer; 3026 size_t buflen; 3027 int fd; 3028 }; 3029 3030 static void * 3031 try_library_path(const char *dir, size_t dirlen, void *param) 3032 { 3033 struct try_library_args *arg; 3034 int fd; 3035 3036 arg = param; 3037 if (*dir == '/' || trust) { 3038 char *pathname; 3039 3040 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3041 return (NULL); 3042 3043 pathname = arg->buffer; 3044 strncpy(pathname, dir, dirlen); 3045 pathname[dirlen] = '/'; 3046 strcpy(pathname + dirlen + 1, arg->name); 3047 3048 dbg(" Trying \"%s\"", pathname); 3049 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3050 if (fd >= 0) { 3051 dbg(" Opened \"%s\", fd %d", pathname, fd); 3052 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3053 strcpy(pathname, arg->buffer); 3054 arg->fd = fd; 3055 return (pathname); 3056 } else { 3057 dbg(" Failed to open \"%s\": %s", 3058 pathname, rtld_strerror(errno)); 3059 } 3060 } 3061 return (NULL); 3062 } 3063 3064 static char * 3065 search_library_path(const char *name, const char *path, 3066 const char *refobj_path, int *fdp) 3067 { 3068 char *p; 3069 struct try_library_args arg; 3070 3071 if (path == NULL) 3072 return NULL; 3073 3074 arg.name = name; 3075 arg.namelen = strlen(name); 3076 arg.buffer = xmalloc(PATH_MAX); 3077 arg.buflen = PATH_MAX; 3078 arg.fd = -1; 3079 3080 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3081 *fdp = arg.fd; 3082 3083 free(arg.buffer); 3084 3085 return (p); 3086 } 3087 3088 3089 /* 3090 * Finds the library with the given name using the directory descriptors 3091 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3092 * 3093 * Returns a freshly-opened close-on-exec file descriptor for the library, 3094 * or -1 if the library cannot be found. 3095 */ 3096 static char * 3097 search_library_pathfds(const char *name, const char *path, int *fdp) 3098 { 3099 char *envcopy, *fdstr, *found, *last_token; 3100 size_t len; 3101 int dirfd, fd; 3102 3103 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3104 3105 /* Don't load from user-specified libdirs into setuid binaries. */ 3106 if (!trust) 3107 return (NULL); 3108 3109 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3110 if (path == NULL) 3111 return (NULL); 3112 3113 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3114 if (name[0] == '/') { 3115 dbg("Absolute path (%s) passed to %s", name, __func__); 3116 return (NULL); 3117 } 3118 3119 /* 3120 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3121 * copy of the path, as strtok_r rewrites separator tokens 3122 * with '\0'. 3123 */ 3124 found = NULL; 3125 envcopy = xstrdup(path); 3126 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3127 fdstr = strtok_r(NULL, ":", &last_token)) { 3128 dirfd = parse_integer(fdstr); 3129 if (dirfd < 0) { 3130 _rtld_error("failed to parse directory FD: '%s'", 3131 fdstr); 3132 break; 3133 } 3134 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3135 if (fd >= 0) { 3136 *fdp = fd; 3137 len = strlen(fdstr) + strlen(name) + 3; 3138 found = xmalloc(len); 3139 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3140 _rtld_error("error generating '%d/%s'", 3141 dirfd, name); 3142 rtld_die(); 3143 } 3144 dbg("open('%s') => %d", found, fd); 3145 break; 3146 } 3147 } 3148 free(envcopy); 3149 3150 return (found); 3151 } 3152 3153 3154 int 3155 dlclose(void *handle) 3156 { 3157 RtldLockState lockstate; 3158 int error; 3159 3160 wlock_acquire(rtld_bind_lock, &lockstate); 3161 error = dlclose_locked(handle, &lockstate); 3162 lock_release(rtld_bind_lock, &lockstate); 3163 return (error); 3164 } 3165 3166 static int 3167 dlclose_locked(void *handle, RtldLockState *lockstate) 3168 { 3169 Obj_Entry *root; 3170 3171 root = dlcheck(handle); 3172 if (root == NULL) 3173 return -1; 3174 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3175 root->path); 3176 3177 /* Unreference the object and its dependencies. */ 3178 root->dl_refcount--; 3179 3180 if (root->refcount == 1) { 3181 /* 3182 * The object will be no longer referenced, so we must unload it. 3183 * First, call the fini functions. 3184 */ 3185 objlist_call_fini(&list_fini, root, lockstate); 3186 3187 unref_dag(root); 3188 3189 /* Finish cleaning up the newly-unreferenced objects. */ 3190 GDB_STATE(RT_DELETE,&root->linkmap); 3191 unload_object(root, lockstate); 3192 GDB_STATE(RT_CONSISTENT,NULL); 3193 } else 3194 unref_dag(root); 3195 3196 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3197 return 0; 3198 } 3199 3200 char * 3201 dlerror(void) 3202 { 3203 char *msg = error_message; 3204 error_message = NULL; 3205 return msg; 3206 } 3207 3208 /* 3209 * This function is deprecated and has no effect. 3210 */ 3211 void 3212 dllockinit(void *context, 3213 void *(*lock_create)(void *context), 3214 void (*rlock_acquire)(void *lock), 3215 void (*wlock_acquire)(void *lock), 3216 void (*lock_release)(void *lock), 3217 void (*lock_destroy)(void *lock), 3218 void (*context_destroy)(void *context)) 3219 { 3220 static void *cur_context; 3221 static void (*cur_context_destroy)(void *); 3222 3223 /* Just destroy the context from the previous call, if necessary. */ 3224 if (cur_context_destroy != NULL) 3225 cur_context_destroy(cur_context); 3226 cur_context = context; 3227 cur_context_destroy = context_destroy; 3228 } 3229 3230 void * 3231 dlopen(const char *name, int mode) 3232 { 3233 3234 return (rtld_dlopen(name, -1, mode)); 3235 } 3236 3237 void * 3238 fdlopen(int fd, int mode) 3239 { 3240 3241 return (rtld_dlopen(NULL, fd, mode)); 3242 } 3243 3244 static void * 3245 rtld_dlopen(const char *name, int fd, int mode) 3246 { 3247 RtldLockState lockstate; 3248 int lo_flags; 3249 3250 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3251 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3252 if (ld_tracing != NULL) { 3253 rlock_acquire(rtld_bind_lock, &lockstate); 3254 if (sigsetjmp(lockstate.env, 0) != 0) 3255 lock_upgrade(rtld_bind_lock, &lockstate); 3256 environ = (char **)*get_program_var_addr("environ", &lockstate); 3257 lock_release(rtld_bind_lock, &lockstate); 3258 } 3259 lo_flags = RTLD_LO_DLOPEN; 3260 if (mode & RTLD_NODELETE) 3261 lo_flags |= RTLD_LO_NODELETE; 3262 if (mode & RTLD_NOLOAD) 3263 lo_flags |= RTLD_LO_NOLOAD; 3264 if (ld_tracing != NULL) 3265 lo_flags |= RTLD_LO_TRACE; 3266 3267 return (dlopen_object(name, fd, obj_main, lo_flags, 3268 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3269 } 3270 3271 static void 3272 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3273 { 3274 3275 obj->dl_refcount--; 3276 unref_dag(obj); 3277 if (obj->refcount == 0) 3278 unload_object(obj, lockstate); 3279 } 3280 3281 static Obj_Entry * 3282 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3283 int mode, RtldLockState *lockstate) 3284 { 3285 Obj_Entry *old_obj_tail; 3286 Obj_Entry *obj; 3287 Objlist initlist; 3288 RtldLockState mlockstate; 3289 int result; 3290 3291 objlist_init(&initlist); 3292 3293 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3294 wlock_acquire(rtld_bind_lock, &mlockstate); 3295 lockstate = &mlockstate; 3296 } 3297 GDB_STATE(RT_ADD,NULL); 3298 3299 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3300 obj = NULL; 3301 if (name == NULL && fd == -1) { 3302 obj = obj_main; 3303 obj->refcount++; 3304 } else { 3305 obj = load_object(name, fd, refobj, lo_flags); 3306 } 3307 3308 if (obj) { 3309 obj->dl_refcount++; 3310 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3311 objlist_push_tail(&list_global, obj); 3312 if (globallist_next(old_obj_tail) != NULL) { 3313 /* We loaded something new. */ 3314 assert(globallist_next(old_obj_tail) == obj); 3315 result = load_needed_objects(obj, 3316 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3317 init_dag(obj); 3318 ref_dag(obj); 3319 if (result != -1) 3320 result = rtld_verify_versions(&obj->dagmembers); 3321 if (result != -1 && ld_tracing) 3322 goto trace; 3323 if (result == -1 || relocate_object_dag(obj, 3324 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3325 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3326 lockstate) == -1) { 3327 dlopen_cleanup(obj, lockstate); 3328 obj = NULL; 3329 } else if (lo_flags & RTLD_LO_EARLY) { 3330 /* 3331 * Do not call the init functions for early loaded 3332 * filtees. The image is still not initialized enough 3333 * for them to work. 3334 * 3335 * Our object is found by the global object list and 3336 * will be ordered among all init calls done right 3337 * before transferring control to main. 3338 */ 3339 } else { 3340 /* Make list of init functions to call. */ 3341 initlist_add_objects(obj, obj, &initlist); 3342 } 3343 /* 3344 * Process all no_delete or global objects here, given 3345 * them own DAGs to prevent their dependencies from being 3346 * unloaded. This has to be done after we have loaded all 3347 * of the dependencies, so that we do not miss any. 3348 */ 3349 if (obj != NULL) 3350 process_z(obj); 3351 } else { 3352 /* 3353 * Bump the reference counts for objects on this DAG. If 3354 * this is the first dlopen() call for the object that was 3355 * already loaded as a dependency, initialize the dag 3356 * starting at it. 3357 */ 3358 init_dag(obj); 3359 ref_dag(obj); 3360 3361 if ((lo_flags & RTLD_LO_TRACE) != 0) 3362 goto trace; 3363 } 3364 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3365 obj->z_nodelete) && !obj->ref_nodel) { 3366 dbg("obj %s nodelete", obj->path); 3367 ref_dag(obj); 3368 obj->z_nodelete = obj->ref_nodel = true; 3369 } 3370 } 3371 3372 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3373 name); 3374 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3375 3376 if (!(lo_flags & RTLD_LO_EARLY)) { 3377 map_stacks_exec(lockstate); 3378 } 3379 3380 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3381 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3382 lockstate) == -1) { 3383 objlist_clear(&initlist); 3384 dlopen_cleanup(obj, lockstate); 3385 if (lockstate == &mlockstate) 3386 lock_release(rtld_bind_lock, lockstate); 3387 return (NULL); 3388 } 3389 3390 if (!(lo_flags & RTLD_LO_EARLY)) { 3391 /* Call the init functions. */ 3392 objlist_call_init(&initlist, lockstate); 3393 } 3394 objlist_clear(&initlist); 3395 if (lockstate == &mlockstate) 3396 lock_release(rtld_bind_lock, lockstate); 3397 return obj; 3398 trace: 3399 trace_loaded_objects(obj); 3400 if (lockstate == &mlockstate) 3401 lock_release(rtld_bind_lock, lockstate); 3402 exit(0); 3403 } 3404 3405 static void * 3406 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3407 int flags) 3408 { 3409 DoneList donelist; 3410 const Obj_Entry *obj, *defobj; 3411 const Elf_Sym *def; 3412 SymLook req; 3413 RtldLockState lockstate; 3414 tls_index ti; 3415 void *sym; 3416 int res; 3417 3418 def = NULL; 3419 defobj = NULL; 3420 symlook_init(&req, name); 3421 req.ventry = ve; 3422 req.flags = flags | SYMLOOK_IN_PLT; 3423 req.lockstate = &lockstate; 3424 3425 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3426 rlock_acquire(rtld_bind_lock, &lockstate); 3427 if (sigsetjmp(lockstate.env, 0) != 0) 3428 lock_upgrade(rtld_bind_lock, &lockstate); 3429 if (handle == NULL || handle == RTLD_NEXT || 3430 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3431 3432 if ((obj = obj_from_addr(retaddr)) == NULL) { 3433 _rtld_error("Cannot determine caller's shared object"); 3434 lock_release(rtld_bind_lock, &lockstate); 3435 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3436 return NULL; 3437 } 3438 if (handle == NULL) { /* Just the caller's shared object. */ 3439 res = symlook_obj(&req, obj); 3440 if (res == 0) { 3441 def = req.sym_out; 3442 defobj = req.defobj_out; 3443 } 3444 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3445 handle == RTLD_SELF) { /* ... caller included */ 3446 if (handle == RTLD_NEXT) 3447 obj = globallist_next(obj); 3448 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3449 if (obj->marker) 3450 continue; 3451 res = symlook_obj(&req, obj); 3452 if (res == 0) { 3453 if (def == NULL || 3454 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3455 def = req.sym_out; 3456 defobj = req.defobj_out; 3457 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3458 break; 3459 } 3460 } 3461 } 3462 /* 3463 * Search the dynamic linker itself, and possibly resolve the 3464 * symbol from there. This is how the application links to 3465 * dynamic linker services such as dlopen. 3466 */ 3467 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3468 res = symlook_obj(&req, &obj_rtld); 3469 if (res == 0) { 3470 def = req.sym_out; 3471 defobj = req.defobj_out; 3472 } 3473 } 3474 } else { 3475 assert(handle == RTLD_DEFAULT); 3476 res = symlook_default(&req, obj); 3477 if (res == 0) { 3478 defobj = req.defobj_out; 3479 def = req.sym_out; 3480 } 3481 } 3482 } else { 3483 if ((obj = dlcheck(handle)) == NULL) { 3484 lock_release(rtld_bind_lock, &lockstate); 3485 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3486 return NULL; 3487 } 3488 3489 donelist_init(&donelist); 3490 if (obj->mainprog) { 3491 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3492 res = symlook_global(&req, &donelist); 3493 if (res == 0) { 3494 def = req.sym_out; 3495 defobj = req.defobj_out; 3496 } 3497 /* 3498 * Search the dynamic linker itself, and possibly resolve the 3499 * symbol from there. This is how the application links to 3500 * dynamic linker services such as dlopen. 3501 */ 3502 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3503 res = symlook_obj(&req, &obj_rtld); 3504 if (res == 0) { 3505 def = req.sym_out; 3506 defobj = req.defobj_out; 3507 } 3508 } 3509 } 3510 else { 3511 /* Search the whole DAG rooted at the given object. */ 3512 res = symlook_list(&req, &obj->dagmembers, &donelist); 3513 if (res == 0) { 3514 def = req.sym_out; 3515 defobj = req.defobj_out; 3516 } 3517 } 3518 } 3519 3520 if (def != NULL) { 3521 lock_release(rtld_bind_lock, &lockstate); 3522 3523 /* 3524 * The value required by the caller is derived from the value 3525 * of the symbol. this is simply the relocated value of the 3526 * symbol. 3527 */ 3528 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3529 sym = make_function_pointer(def, defobj); 3530 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3531 sym = rtld_resolve_ifunc(defobj, def); 3532 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3533 ti.ti_module = defobj->tlsindex; 3534 ti.ti_offset = def->st_value; 3535 sym = __tls_get_addr(&ti); 3536 } else 3537 sym = defobj->relocbase + def->st_value; 3538 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3539 return (sym); 3540 } 3541 3542 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3543 ve != NULL ? ve->name : ""); 3544 lock_release(rtld_bind_lock, &lockstate); 3545 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3546 return NULL; 3547 } 3548 3549 void * 3550 dlsym(void *handle, const char *name) 3551 { 3552 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3553 SYMLOOK_DLSYM); 3554 } 3555 3556 dlfunc_t 3557 dlfunc(void *handle, const char *name) 3558 { 3559 union { 3560 void *d; 3561 dlfunc_t f; 3562 } rv; 3563 3564 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3565 SYMLOOK_DLSYM); 3566 return (rv.f); 3567 } 3568 3569 void * 3570 dlvsym(void *handle, const char *name, const char *version) 3571 { 3572 Ver_Entry ventry; 3573 3574 ventry.name = version; 3575 ventry.file = NULL; 3576 ventry.hash = elf_hash(version); 3577 ventry.flags= 0; 3578 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3579 SYMLOOK_DLSYM); 3580 } 3581 3582 int 3583 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3584 { 3585 const Obj_Entry *obj; 3586 RtldLockState lockstate; 3587 3588 rlock_acquire(rtld_bind_lock, &lockstate); 3589 obj = obj_from_addr(addr); 3590 if (obj == NULL) { 3591 _rtld_error("No shared object contains address"); 3592 lock_release(rtld_bind_lock, &lockstate); 3593 return (0); 3594 } 3595 rtld_fill_dl_phdr_info(obj, phdr_info); 3596 lock_release(rtld_bind_lock, &lockstate); 3597 return (1); 3598 } 3599 3600 int 3601 dladdr(const void *addr, Dl_info *info) 3602 { 3603 const Obj_Entry *obj; 3604 const Elf_Sym *def; 3605 void *symbol_addr; 3606 unsigned long symoffset; 3607 RtldLockState lockstate; 3608 3609 rlock_acquire(rtld_bind_lock, &lockstate); 3610 obj = obj_from_addr(addr); 3611 if (obj == NULL) { 3612 _rtld_error("No shared object contains address"); 3613 lock_release(rtld_bind_lock, &lockstate); 3614 return 0; 3615 } 3616 info->dli_fname = obj->path; 3617 info->dli_fbase = obj->mapbase; 3618 info->dli_saddr = (void *)0; 3619 info->dli_sname = NULL; 3620 3621 /* 3622 * Walk the symbol list looking for the symbol whose address is 3623 * closest to the address sent in. 3624 */ 3625 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3626 def = obj->symtab + symoffset; 3627 3628 /* 3629 * For skip the symbol if st_shndx is either SHN_UNDEF or 3630 * SHN_COMMON. 3631 */ 3632 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3633 continue; 3634 3635 /* 3636 * If the symbol is greater than the specified address, or if it 3637 * is further away from addr than the current nearest symbol, 3638 * then reject it. 3639 */ 3640 symbol_addr = obj->relocbase + def->st_value; 3641 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3642 continue; 3643 3644 /* Update our idea of the nearest symbol. */ 3645 info->dli_sname = obj->strtab + def->st_name; 3646 info->dli_saddr = symbol_addr; 3647 3648 /* Exact match? */ 3649 if (info->dli_saddr == addr) 3650 break; 3651 } 3652 lock_release(rtld_bind_lock, &lockstate); 3653 return 1; 3654 } 3655 3656 int 3657 dlinfo(void *handle, int request, void *p) 3658 { 3659 const Obj_Entry *obj; 3660 RtldLockState lockstate; 3661 int error; 3662 3663 rlock_acquire(rtld_bind_lock, &lockstate); 3664 3665 if (handle == NULL || handle == RTLD_SELF) { 3666 void *retaddr; 3667 3668 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3669 if ((obj = obj_from_addr(retaddr)) == NULL) 3670 _rtld_error("Cannot determine caller's shared object"); 3671 } else 3672 obj = dlcheck(handle); 3673 3674 if (obj == NULL) { 3675 lock_release(rtld_bind_lock, &lockstate); 3676 return (-1); 3677 } 3678 3679 error = 0; 3680 switch (request) { 3681 case RTLD_DI_LINKMAP: 3682 *((struct link_map const **)p) = &obj->linkmap; 3683 break; 3684 case RTLD_DI_ORIGIN: 3685 error = rtld_dirname(obj->path, p); 3686 break; 3687 3688 case RTLD_DI_SERINFOSIZE: 3689 case RTLD_DI_SERINFO: 3690 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3691 break; 3692 3693 default: 3694 _rtld_error("Invalid request %d passed to dlinfo()", request); 3695 error = -1; 3696 } 3697 3698 lock_release(rtld_bind_lock, &lockstate); 3699 3700 return (error); 3701 } 3702 3703 static void 3704 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3705 { 3706 3707 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3708 phdr_info->dlpi_name = obj->path; 3709 phdr_info->dlpi_phdr = obj->phdr; 3710 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3711 phdr_info->dlpi_tls_modid = obj->tlsindex; 3712 phdr_info->dlpi_tls_data = obj->tlsinit; 3713 phdr_info->dlpi_adds = obj_loads; 3714 phdr_info->dlpi_subs = obj_loads - obj_count; 3715 } 3716 3717 int 3718 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3719 { 3720 struct dl_phdr_info phdr_info; 3721 Obj_Entry *obj, marker; 3722 RtldLockState bind_lockstate, phdr_lockstate; 3723 int error; 3724 3725 init_marker(&marker); 3726 error = 0; 3727 3728 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3729 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3730 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3731 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3732 rtld_fill_dl_phdr_info(obj, &phdr_info); 3733 hold_object(obj); 3734 lock_release(rtld_bind_lock, &bind_lockstate); 3735 3736 error = callback(&phdr_info, sizeof phdr_info, param); 3737 3738 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3739 unhold_object(obj); 3740 obj = globallist_next(&marker); 3741 TAILQ_REMOVE(&obj_list, &marker, next); 3742 if (error != 0) { 3743 lock_release(rtld_bind_lock, &bind_lockstate); 3744 lock_release(rtld_phdr_lock, &phdr_lockstate); 3745 return (error); 3746 } 3747 } 3748 3749 if (error == 0) { 3750 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3751 lock_release(rtld_bind_lock, &bind_lockstate); 3752 error = callback(&phdr_info, sizeof(phdr_info), param); 3753 } 3754 lock_release(rtld_phdr_lock, &phdr_lockstate); 3755 return (error); 3756 } 3757 3758 static void * 3759 fill_search_info(const char *dir, size_t dirlen, void *param) 3760 { 3761 struct fill_search_info_args *arg; 3762 3763 arg = param; 3764 3765 if (arg->request == RTLD_DI_SERINFOSIZE) { 3766 arg->serinfo->dls_cnt ++; 3767 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3768 } else { 3769 struct dl_serpath *s_entry; 3770 3771 s_entry = arg->serpath; 3772 s_entry->dls_name = arg->strspace; 3773 s_entry->dls_flags = arg->flags; 3774 3775 strncpy(arg->strspace, dir, dirlen); 3776 arg->strspace[dirlen] = '\0'; 3777 3778 arg->strspace += dirlen + 1; 3779 arg->serpath++; 3780 } 3781 3782 return (NULL); 3783 } 3784 3785 static int 3786 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3787 { 3788 struct dl_serinfo _info; 3789 struct fill_search_info_args args; 3790 3791 args.request = RTLD_DI_SERINFOSIZE; 3792 args.serinfo = &_info; 3793 3794 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3795 _info.dls_cnt = 0; 3796 3797 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3798 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3799 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3800 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3801 if (!obj->z_nodeflib) 3802 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3803 3804 3805 if (request == RTLD_DI_SERINFOSIZE) { 3806 info->dls_size = _info.dls_size; 3807 info->dls_cnt = _info.dls_cnt; 3808 return (0); 3809 } 3810 3811 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3812 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3813 return (-1); 3814 } 3815 3816 args.request = RTLD_DI_SERINFO; 3817 args.serinfo = info; 3818 args.serpath = &info->dls_serpath[0]; 3819 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3820 3821 args.flags = LA_SER_RUNPATH; 3822 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3823 return (-1); 3824 3825 args.flags = LA_SER_LIBPATH; 3826 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3827 return (-1); 3828 3829 args.flags = LA_SER_RUNPATH; 3830 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3831 return (-1); 3832 3833 args.flags = LA_SER_CONFIG; 3834 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3835 != NULL) 3836 return (-1); 3837 3838 args.flags = LA_SER_DEFAULT; 3839 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3840 fill_search_info, NULL, &args) != NULL) 3841 return (-1); 3842 return (0); 3843 } 3844 3845 static int 3846 rtld_dirname(const char *path, char *bname) 3847 { 3848 const char *endp; 3849 3850 /* Empty or NULL string gets treated as "." */ 3851 if (path == NULL || *path == '\0') { 3852 bname[0] = '.'; 3853 bname[1] = '\0'; 3854 return (0); 3855 } 3856 3857 /* Strip trailing slashes */ 3858 endp = path + strlen(path) - 1; 3859 while (endp > path && *endp == '/') 3860 endp--; 3861 3862 /* Find the start of the dir */ 3863 while (endp > path && *endp != '/') 3864 endp--; 3865 3866 /* Either the dir is "/" or there are no slashes */ 3867 if (endp == path) { 3868 bname[0] = *endp == '/' ? '/' : '.'; 3869 bname[1] = '\0'; 3870 return (0); 3871 } else { 3872 do { 3873 endp--; 3874 } while (endp > path && *endp == '/'); 3875 } 3876 3877 if (endp - path + 2 > PATH_MAX) 3878 { 3879 _rtld_error("Filename is too long: %s", path); 3880 return(-1); 3881 } 3882 3883 strncpy(bname, path, endp - path + 1); 3884 bname[endp - path + 1] = '\0'; 3885 return (0); 3886 } 3887 3888 static int 3889 rtld_dirname_abs(const char *path, char *base) 3890 { 3891 char *last; 3892 3893 if (realpath(path, base) == NULL) 3894 return (-1); 3895 dbg("%s -> %s", path, base); 3896 last = strrchr(base, '/'); 3897 if (last == NULL) 3898 return (-1); 3899 if (last != base) 3900 *last = '\0'; 3901 return (0); 3902 } 3903 3904 static void 3905 linkmap_add(Obj_Entry *obj) 3906 { 3907 struct link_map *l = &obj->linkmap; 3908 struct link_map *prev; 3909 3910 obj->linkmap.l_name = obj->path; 3911 obj->linkmap.l_addr = obj->mapbase; 3912 obj->linkmap.l_ld = obj->dynamic; 3913 #ifdef __mips__ 3914 /* GDB needs load offset on MIPS to use the symbols */ 3915 obj->linkmap.l_offs = obj->relocbase; 3916 #endif 3917 3918 if (r_debug.r_map == NULL) { 3919 r_debug.r_map = l; 3920 return; 3921 } 3922 3923 /* 3924 * Scan to the end of the list, but not past the entry for the 3925 * dynamic linker, which we want to keep at the very end. 3926 */ 3927 for (prev = r_debug.r_map; 3928 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3929 prev = prev->l_next) 3930 ; 3931 3932 /* Link in the new entry. */ 3933 l->l_prev = prev; 3934 l->l_next = prev->l_next; 3935 if (l->l_next != NULL) 3936 l->l_next->l_prev = l; 3937 prev->l_next = l; 3938 } 3939 3940 static void 3941 linkmap_delete(Obj_Entry *obj) 3942 { 3943 struct link_map *l = &obj->linkmap; 3944 3945 if (l->l_prev == NULL) { 3946 if ((r_debug.r_map = l->l_next) != NULL) 3947 l->l_next->l_prev = NULL; 3948 return; 3949 } 3950 3951 if ((l->l_prev->l_next = l->l_next) != NULL) 3952 l->l_next->l_prev = l->l_prev; 3953 } 3954 3955 /* 3956 * Function for the debugger to set a breakpoint on to gain control. 3957 * 3958 * The two parameters allow the debugger to easily find and determine 3959 * what the runtime loader is doing and to whom it is doing it. 3960 * 3961 * When the loadhook trap is hit (r_debug_state, set at program 3962 * initialization), the arguments can be found on the stack: 3963 * 3964 * +8 struct link_map *m 3965 * +4 struct r_debug *rd 3966 * +0 RetAddr 3967 */ 3968 void 3969 r_debug_state(struct r_debug* rd, struct link_map *m) 3970 { 3971 /* 3972 * The following is a hack to force the compiler to emit calls to 3973 * this function, even when optimizing. If the function is empty, 3974 * the compiler is not obliged to emit any code for calls to it, 3975 * even when marked __noinline. However, gdb depends on those 3976 * calls being made. 3977 */ 3978 __compiler_membar(); 3979 } 3980 3981 /* 3982 * A function called after init routines have completed. This can be used to 3983 * break before a program's entry routine is called, and can be used when 3984 * main is not available in the symbol table. 3985 */ 3986 void 3987 _r_debug_postinit(struct link_map *m) 3988 { 3989 3990 /* See r_debug_state(). */ 3991 __compiler_membar(); 3992 } 3993 3994 static void 3995 release_object(Obj_Entry *obj) 3996 { 3997 3998 if (obj->holdcount > 0) { 3999 obj->unholdfree = true; 4000 return; 4001 } 4002 munmap(obj->mapbase, obj->mapsize); 4003 linkmap_delete(obj); 4004 obj_free(obj); 4005 } 4006 4007 /* 4008 * Get address of the pointer variable in the main program. 4009 * Prefer non-weak symbol over the weak one. 4010 */ 4011 static const void ** 4012 get_program_var_addr(const char *name, RtldLockState *lockstate) 4013 { 4014 SymLook req; 4015 DoneList donelist; 4016 4017 symlook_init(&req, name); 4018 req.lockstate = lockstate; 4019 donelist_init(&donelist); 4020 if (symlook_global(&req, &donelist) != 0) 4021 return (NULL); 4022 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4023 return ((const void **)make_function_pointer(req.sym_out, 4024 req.defobj_out)); 4025 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4026 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4027 else 4028 return ((const void **)(req.defobj_out->relocbase + 4029 req.sym_out->st_value)); 4030 } 4031 4032 /* 4033 * Set a pointer variable in the main program to the given value. This 4034 * is used to set key variables such as "environ" before any of the 4035 * init functions are called. 4036 */ 4037 static void 4038 set_program_var(const char *name, const void *value) 4039 { 4040 const void **addr; 4041 4042 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4043 dbg("\"%s\": *%p <-- %p", name, addr, value); 4044 *addr = value; 4045 } 4046 } 4047 4048 /* 4049 * Search the global objects, including dependencies and main object, 4050 * for the given symbol. 4051 */ 4052 static int 4053 symlook_global(SymLook *req, DoneList *donelist) 4054 { 4055 SymLook req1; 4056 const Objlist_Entry *elm; 4057 int res; 4058 4059 symlook_init_from_req(&req1, req); 4060 4061 /* Search all objects loaded at program start up. */ 4062 if (req->defobj_out == NULL || 4063 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4064 res = symlook_list(&req1, &list_main, donelist); 4065 if (res == 0 && (req->defobj_out == NULL || 4066 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4067 req->sym_out = req1.sym_out; 4068 req->defobj_out = req1.defobj_out; 4069 assert(req->defobj_out != NULL); 4070 } 4071 } 4072 4073 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4074 STAILQ_FOREACH(elm, &list_global, link) { 4075 if (req->defobj_out != NULL && 4076 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4077 break; 4078 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4079 if (res == 0 && (req->defobj_out == NULL || 4080 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4081 req->sym_out = req1.sym_out; 4082 req->defobj_out = req1.defobj_out; 4083 assert(req->defobj_out != NULL); 4084 } 4085 } 4086 4087 return (req->sym_out != NULL ? 0 : ESRCH); 4088 } 4089 4090 /* 4091 * Given a symbol name in a referencing object, find the corresponding 4092 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4093 * no definition was found. Returns a pointer to the Obj_Entry of the 4094 * defining object via the reference parameter DEFOBJ_OUT. 4095 */ 4096 static int 4097 symlook_default(SymLook *req, const Obj_Entry *refobj) 4098 { 4099 DoneList donelist; 4100 const Objlist_Entry *elm; 4101 SymLook req1; 4102 int res; 4103 4104 donelist_init(&donelist); 4105 symlook_init_from_req(&req1, req); 4106 4107 /* 4108 * Look first in the referencing object if linked symbolically, 4109 * and similarly handle protected symbols. 4110 */ 4111 res = symlook_obj(&req1, refobj); 4112 if (res == 0 && (refobj->symbolic || 4113 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4114 req->sym_out = req1.sym_out; 4115 req->defobj_out = req1.defobj_out; 4116 assert(req->defobj_out != NULL); 4117 } 4118 if (refobj->symbolic || req->defobj_out != NULL) 4119 donelist_check(&donelist, refobj); 4120 4121 symlook_global(req, &donelist); 4122 4123 /* Search all dlopened DAGs containing the referencing object. */ 4124 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4125 if (req->sym_out != NULL && 4126 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4127 break; 4128 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4129 if (res == 0 && (req->sym_out == NULL || 4130 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4131 req->sym_out = req1.sym_out; 4132 req->defobj_out = req1.defobj_out; 4133 assert(req->defobj_out != NULL); 4134 } 4135 } 4136 4137 /* 4138 * Search the dynamic linker itself, and possibly resolve the 4139 * symbol from there. This is how the application links to 4140 * dynamic linker services such as dlopen. 4141 */ 4142 if (req->sym_out == NULL || 4143 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4144 res = symlook_obj(&req1, &obj_rtld); 4145 if (res == 0) { 4146 req->sym_out = req1.sym_out; 4147 req->defobj_out = req1.defobj_out; 4148 assert(req->defobj_out != NULL); 4149 } 4150 } 4151 4152 return (req->sym_out != NULL ? 0 : ESRCH); 4153 } 4154 4155 static int 4156 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4157 { 4158 const Elf_Sym *def; 4159 const Obj_Entry *defobj; 4160 const Objlist_Entry *elm; 4161 SymLook req1; 4162 int res; 4163 4164 def = NULL; 4165 defobj = NULL; 4166 STAILQ_FOREACH(elm, objlist, link) { 4167 if (donelist_check(dlp, elm->obj)) 4168 continue; 4169 symlook_init_from_req(&req1, req); 4170 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4171 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4172 def = req1.sym_out; 4173 defobj = req1.defobj_out; 4174 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4175 break; 4176 } 4177 } 4178 } 4179 if (def != NULL) { 4180 req->sym_out = def; 4181 req->defobj_out = defobj; 4182 return (0); 4183 } 4184 return (ESRCH); 4185 } 4186 4187 /* 4188 * Search the chain of DAGS cointed to by the given Needed_Entry 4189 * for a symbol of the given name. Each DAG is scanned completely 4190 * before advancing to the next one. Returns a pointer to the symbol, 4191 * or NULL if no definition was found. 4192 */ 4193 static int 4194 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4195 { 4196 const Elf_Sym *def; 4197 const Needed_Entry *n; 4198 const Obj_Entry *defobj; 4199 SymLook req1; 4200 int res; 4201 4202 def = NULL; 4203 defobj = NULL; 4204 symlook_init_from_req(&req1, req); 4205 for (n = needed; n != NULL; n = n->next) { 4206 if (n->obj == NULL || 4207 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4208 continue; 4209 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4210 def = req1.sym_out; 4211 defobj = req1.defobj_out; 4212 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4213 break; 4214 } 4215 } 4216 if (def != NULL) { 4217 req->sym_out = def; 4218 req->defobj_out = defobj; 4219 return (0); 4220 } 4221 return (ESRCH); 4222 } 4223 4224 /* 4225 * Search the symbol table of a single shared object for a symbol of 4226 * the given name and version, if requested. Returns a pointer to the 4227 * symbol, or NULL if no definition was found. If the object is 4228 * filter, return filtered symbol from filtee. 4229 * 4230 * The symbol's hash value is passed in for efficiency reasons; that 4231 * eliminates many recomputations of the hash value. 4232 */ 4233 int 4234 symlook_obj(SymLook *req, const Obj_Entry *obj) 4235 { 4236 DoneList donelist; 4237 SymLook req1; 4238 int flags, res, mres; 4239 4240 /* 4241 * If there is at least one valid hash at this point, we prefer to 4242 * use the faster GNU version if available. 4243 */ 4244 if (obj->valid_hash_gnu) 4245 mres = symlook_obj1_gnu(req, obj); 4246 else if (obj->valid_hash_sysv) 4247 mres = symlook_obj1_sysv(req, obj); 4248 else 4249 return (EINVAL); 4250 4251 if (mres == 0) { 4252 if (obj->needed_filtees != NULL) { 4253 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4254 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4255 donelist_init(&donelist); 4256 symlook_init_from_req(&req1, req); 4257 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4258 if (res == 0) { 4259 req->sym_out = req1.sym_out; 4260 req->defobj_out = req1.defobj_out; 4261 } 4262 return (res); 4263 } 4264 if (obj->needed_aux_filtees != NULL) { 4265 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4266 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4267 donelist_init(&donelist); 4268 symlook_init_from_req(&req1, req); 4269 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4270 if (res == 0) { 4271 req->sym_out = req1.sym_out; 4272 req->defobj_out = req1.defobj_out; 4273 return (res); 4274 } 4275 } 4276 } 4277 return (mres); 4278 } 4279 4280 /* Symbol match routine common to both hash functions */ 4281 static bool 4282 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4283 const unsigned long symnum) 4284 { 4285 Elf_Versym verndx; 4286 const Elf_Sym *symp; 4287 const char *strp; 4288 4289 symp = obj->symtab + symnum; 4290 strp = obj->strtab + symp->st_name; 4291 4292 switch (ELF_ST_TYPE(symp->st_info)) { 4293 case STT_FUNC: 4294 case STT_NOTYPE: 4295 case STT_OBJECT: 4296 case STT_COMMON: 4297 case STT_GNU_IFUNC: 4298 if (symp->st_value == 0) 4299 return (false); 4300 /* fallthrough */ 4301 case STT_TLS: 4302 if (symp->st_shndx != SHN_UNDEF) 4303 break; 4304 #ifndef __mips__ 4305 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4306 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4307 break; 4308 /* fallthrough */ 4309 #endif 4310 default: 4311 return (false); 4312 } 4313 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4314 return (false); 4315 4316 if (req->ventry == NULL) { 4317 if (obj->versyms != NULL) { 4318 verndx = VER_NDX(obj->versyms[symnum]); 4319 if (verndx > obj->vernum) { 4320 _rtld_error( 4321 "%s: symbol %s references wrong version %d", 4322 obj->path, obj->strtab + symnum, verndx); 4323 return (false); 4324 } 4325 /* 4326 * If we are not called from dlsym (i.e. this 4327 * is a normal relocation from unversioned 4328 * binary), accept the symbol immediately if 4329 * it happens to have first version after this 4330 * shared object became versioned. Otherwise, 4331 * if symbol is versioned and not hidden, 4332 * remember it. If it is the only symbol with 4333 * this name exported by the shared object, it 4334 * will be returned as a match by the calling 4335 * function. If symbol is global (verndx < 2) 4336 * accept it unconditionally. 4337 */ 4338 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4339 verndx == VER_NDX_GIVEN) { 4340 result->sym_out = symp; 4341 return (true); 4342 } 4343 else if (verndx >= VER_NDX_GIVEN) { 4344 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4345 == 0) { 4346 if (result->vsymp == NULL) 4347 result->vsymp = symp; 4348 result->vcount++; 4349 } 4350 return (false); 4351 } 4352 } 4353 result->sym_out = symp; 4354 return (true); 4355 } 4356 if (obj->versyms == NULL) { 4357 if (object_match_name(obj, req->ventry->name)) { 4358 _rtld_error("%s: object %s should provide version %s " 4359 "for symbol %s", obj_rtld.path, obj->path, 4360 req->ventry->name, obj->strtab + symnum); 4361 return (false); 4362 } 4363 } else { 4364 verndx = VER_NDX(obj->versyms[symnum]); 4365 if (verndx > obj->vernum) { 4366 _rtld_error("%s: symbol %s references wrong version %d", 4367 obj->path, obj->strtab + symnum, verndx); 4368 return (false); 4369 } 4370 if (obj->vertab[verndx].hash != req->ventry->hash || 4371 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4372 /* 4373 * Version does not match. Look if this is a 4374 * global symbol and if it is not hidden. If 4375 * global symbol (verndx < 2) is available, 4376 * use it. Do not return symbol if we are 4377 * called by dlvsym, because dlvsym looks for 4378 * a specific version and default one is not 4379 * what dlvsym wants. 4380 */ 4381 if ((req->flags & SYMLOOK_DLSYM) || 4382 (verndx >= VER_NDX_GIVEN) || 4383 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4384 return (false); 4385 } 4386 } 4387 result->sym_out = symp; 4388 return (true); 4389 } 4390 4391 /* 4392 * Search for symbol using SysV hash function. 4393 * obj->buckets is known not to be NULL at this point; the test for this was 4394 * performed with the obj->valid_hash_sysv assignment. 4395 */ 4396 static int 4397 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4398 { 4399 unsigned long symnum; 4400 Sym_Match_Result matchres; 4401 4402 matchres.sym_out = NULL; 4403 matchres.vsymp = NULL; 4404 matchres.vcount = 0; 4405 4406 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4407 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4408 if (symnum >= obj->nchains) 4409 return (ESRCH); /* Bad object */ 4410 4411 if (matched_symbol(req, obj, &matchres, symnum)) { 4412 req->sym_out = matchres.sym_out; 4413 req->defobj_out = obj; 4414 return (0); 4415 } 4416 } 4417 if (matchres.vcount == 1) { 4418 req->sym_out = matchres.vsymp; 4419 req->defobj_out = obj; 4420 return (0); 4421 } 4422 return (ESRCH); 4423 } 4424 4425 /* Search for symbol using GNU hash function */ 4426 static int 4427 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4428 { 4429 Elf_Addr bloom_word; 4430 const Elf32_Word *hashval; 4431 Elf32_Word bucket; 4432 Sym_Match_Result matchres; 4433 unsigned int h1, h2; 4434 unsigned long symnum; 4435 4436 matchres.sym_out = NULL; 4437 matchres.vsymp = NULL; 4438 matchres.vcount = 0; 4439 4440 /* Pick right bitmask word from Bloom filter array */ 4441 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4442 obj->maskwords_bm_gnu]; 4443 4444 /* Calculate modulus word size of gnu hash and its derivative */ 4445 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4446 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4447 4448 /* Filter out the "definitely not in set" queries */ 4449 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4450 return (ESRCH); 4451 4452 /* Locate hash chain and corresponding value element*/ 4453 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4454 if (bucket == 0) 4455 return (ESRCH); 4456 hashval = &obj->chain_zero_gnu[bucket]; 4457 do { 4458 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4459 symnum = hashval - obj->chain_zero_gnu; 4460 if (matched_symbol(req, obj, &matchres, symnum)) { 4461 req->sym_out = matchres.sym_out; 4462 req->defobj_out = obj; 4463 return (0); 4464 } 4465 } 4466 } while ((*hashval++ & 1) == 0); 4467 if (matchres.vcount == 1) { 4468 req->sym_out = matchres.vsymp; 4469 req->defobj_out = obj; 4470 return (0); 4471 } 4472 return (ESRCH); 4473 } 4474 4475 static void 4476 trace_loaded_objects(Obj_Entry *obj) 4477 { 4478 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4479 int c; 4480 4481 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4482 main_local = ""; 4483 4484 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4485 fmt1 = "\t%o => %p (%x)\n"; 4486 4487 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4488 fmt2 = "\t%o (%x)\n"; 4489 4490 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4491 4492 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4493 Needed_Entry *needed; 4494 char *name, *path; 4495 bool is_lib; 4496 4497 if (obj->marker) 4498 continue; 4499 if (list_containers && obj->needed != NULL) 4500 rtld_printf("%s:\n", obj->path); 4501 for (needed = obj->needed; needed; needed = needed->next) { 4502 if (needed->obj != NULL) { 4503 if (needed->obj->traced && !list_containers) 4504 continue; 4505 needed->obj->traced = true; 4506 path = needed->obj->path; 4507 } else 4508 path = "not found"; 4509 4510 name = (char *)obj->strtab + needed->name; 4511 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4512 4513 fmt = is_lib ? fmt1 : fmt2; 4514 while ((c = *fmt++) != '\0') { 4515 switch (c) { 4516 default: 4517 rtld_putchar(c); 4518 continue; 4519 case '\\': 4520 switch (c = *fmt) { 4521 case '\0': 4522 continue; 4523 case 'n': 4524 rtld_putchar('\n'); 4525 break; 4526 case 't': 4527 rtld_putchar('\t'); 4528 break; 4529 } 4530 break; 4531 case '%': 4532 switch (c = *fmt) { 4533 case '\0': 4534 continue; 4535 case '%': 4536 default: 4537 rtld_putchar(c); 4538 break; 4539 case 'A': 4540 rtld_putstr(main_local); 4541 break; 4542 case 'a': 4543 rtld_putstr(obj_main->path); 4544 break; 4545 case 'o': 4546 rtld_putstr(name); 4547 break; 4548 #if 0 4549 case 'm': 4550 rtld_printf("%d", sodp->sod_major); 4551 break; 4552 case 'n': 4553 rtld_printf("%d", sodp->sod_minor); 4554 break; 4555 #endif 4556 case 'p': 4557 rtld_putstr(path); 4558 break; 4559 case 'x': 4560 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4561 0); 4562 break; 4563 } 4564 break; 4565 } 4566 ++fmt; 4567 } 4568 } 4569 } 4570 } 4571 4572 /* 4573 * Unload a dlopened object and its dependencies from memory and from 4574 * our data structures. It is assumed that the DAG rooted in the 4575 * object has already been unreferenced, and that the object has a 4576 * reference count of 0. 4577 */ 4578 static void 4579 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4580 { 4581 Obj_Entry marker, *obj, *next; 4582 4583 assert(root->refcount == 0); 4584 4585 /* 4586 * Pass over the DAG removing unreferenced objects from 4587 * appropriate lists. 4588 */ 4589 unlink_object(root); 4590 4591 /* Unmap all objects that are no longer referenced. */ 4592 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4593 next = TAILQ_NEXT(obj, next); 4594 if (obj->marker || obj->refcount != 0) 4595 continue; 4596 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4597 obj->mapsize, 0, obj->path); 4598 dbg("unloading \"%s\"", obj->path); 4599 /* 4600 * Unlink the object now to prevent new references from 4601 * being acquired while the bind lock is dropped in 4602 * recursive dlclose() invocations. 4603 */ 4604 TAILQ_REMOVE(&obj_list, obj, next); 4605 obj_count--; 4606 4607 if (obj->filtees_loaded) { 4608 if (next != NULL) { 4609 init_marker(&marker); 4610 TAILQ_INSERT_BEFORE(next, &marker, next); 4611 unload_filtees(obj, lockstate); 4612 next = TAILQ_NEXT(&marker, next); 4613 TAILQ_REMOVE(&obj_list, &marker, next); 4614 } else 4615 unload_filtees(obj, lockstate); 4616 } 4617 release_object(obj); 4618 } 4619 } 4620 4621 static void 4622 unlink_object(Obj_Entry *root) 4623 { 4624 Objlist_Entry *elm; 4625 4626 if (root->refcount == 0) { 4627 /* Remove the object from the RTLD_GLOBAL list. */ 4628 objlist_remove(&list_global, root); 4629 4630 /* Remove the object from all objects' DAG lists. */ 4631 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4632 objlist_remove(&elm->obj->dldags, root); 4633 if (elm->obj != root) 4634 unlink_object(elm->obj); 4635 } 4636 } 4637 } 4638 4639 static void 4640 ref_dag(Obj_Entry *root) 4641 { 4642 Objlist_Entry *elm; 4643 4644 assert(root->dag_inited); 4645 STAILQ_FOREACH(elm, &root->dagmembers, link) 4646 elm->obj->refcount++; 4647 } 4648 4649 static void 4650 unref_dag(Obj_Entry *root) 4651 { 4652 Objlist_Entry *elm; 4653 4654 assert(root->dag_inited); 4655 STAILQ_FOREACH(elm, &root->dagmembers, link) 4656 elm->obj->refcount--; 4657 } 4658 4659 /* 4660 * Common code for MD __tls_get_addr(). 4661 */ 4662 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4663 static void * 4664 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4665 { 4666 Elf_Addr *newdtv, *dtv; 4667 RtldLockState lockstate; 4668 int to_copy; 4669 4670 dtv = *dtvp; 4671 /* Check dtv generation in case new modules have arrived */ 4672 if (dtv[0] != tls_dtv_generation) { 4673 wlock_acquire(rtld_bind_lock, &lockstate); 4674 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4675 to_copy = dtv[1]; 4676 if (to_copy > tls_max_index) 4677 to_copy = tls_max_index; 4678 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4679 newdtv[0] = tls_dtv_generation; 4680 newdtv[1] = tls_max_index; 4681 free(dtv); 4682 lock_release(rtld_bind_lock, &lockstate); 4683 dtv = *dtvp = newdtv; 4684 } 4685 4686 /* Dynamically allocate module TLS if necessary */ 4687 if (dtv[index + 1] == 0) { 4688 /* Signal safe, wlock will block out signals. */ 4689 wlock_acquire(rtld_bind_lock, &lockstate); 4690 if (!dtv[index + 1]) 4691 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4692 lock_release(rtld_bind_lock, &lockstate); 4693 } 4694 return ((void *)(dtv[index + 1] + offset)); 4695 } 4696 4697 void * 4698 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4699 { 4700 Elf_Addr *dtv; 4701 4702 dtv = *dtvp; 4703 /* Check dtv generation in case new modules have arrived */ 4704 if (__predict_true(dtv[0] == tls_dtv_generation && 4705 dtv[index + 1] != 0)) 4706 return ((void *)(dtv[index + 1] + offset)); 4707 return (tls_get_addr_slow(dtvp, index, offset)); 4708 } 4709 4710 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4711 defined(__powerpc__) || defined(__riscv) 4712 4713 /* 4714 * Return pointer to allocated TLS block 4715 */ 4716 static void * 4717 get_tls_block_ptr(void *tcb, size_t tcbsize) 4718 { 4719 size_t extra_size, post_size, pre_size, tls_block_size; 4720 size_t tls_init_align; 4721 4722 tls_init_align = MAX(obj_main->tlsalign, 1); 4723 4724 /* Compute fragments sizes. */ 4725 extra_size = tcbsize - TLS_TCB_SIZE; 4726 post_size = calculate_tls_post_size(tls_init_align); 4727 tls_block_size = tcbsize + post_size; 4728 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4729 4730 return ((char *)tcb - pre_size - extra_size); 4731 } 4732 4733 /* 4734 * Allocate Static TLS using the Variant I method. 4735 * 4736 * For details on the layout, see lib/libc/gen/tls.c. 4737 * 4738 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4739 * it is based on tls_last_offset, and TLS offsets here are really TCB 4740 * offsets, whereas libc's tls_static_space is just the executable's static 4741 * TLS segment. 4742 */ 4743 void * 4744 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4745 { 4746 Obj_Entry *obj; 4747 char *tls_block; 4748 Elf_Addr *dtv, **tcb; 4749 Elf_Addr addr; 4750 int i; 4751 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4752 size_t tls_init_align; 4753 4754 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4755 return (oldtcb); 4756 4757 assert(tcbsize >= TLS_TCB_SIZE); 4758 maxalign = MAX(tcbalign, tls_static_max_align); 4759 tls_init_align = MAX(obj_main->tlsalign, 1); 4760 4761 /* Compute fragmets sizes. */ 4762 extra_size = tcbsize - TLS_TCB_SIZE; 4763 post_size = calculate_tls_post_size(tls_init_align); 4764 tls_block_size = tcbsize + post_size; 4765 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4766 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4767 4768 /* Allocate whole TLS block */ 4769 tls_block = malloc_aligned(tls_block_size, maxalign); 4770 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4771 4772 if (oldtcb != NULL) { 4773 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4774 tls_static_space); 4775 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4776 4777 /* Adjust the DTV. */ 4778 dtv = tcb[0]; 4779 for (i = 0; i < dtv[1]; i++) { 4780 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4781 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4782 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4783 } 4784 } 4785 } else { 4786 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4787 tcb[0] = dtv; 4788 dtv[0] = tls_dtv_generation; 4789 dtv[1] = tls_max_index; 4790 4791 for (obj = globallist_curr(objs); obj != NULL; 4792 obj = globallist_next(obj)) { 4793 if (obj->tlsoffset > 0) { 4794 addr = (Elf_Addr)tcb + obj->tlsoffset; 4795 if (obj->tlsinitsize > 0) 4796 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4797 if (obj->tlssize > obj->tlsinitsize) 4798 memset((void*) (addr + obj->tlsinitsize), 0, 4799 obj->tlssize - obj->tlsinitsize); 4800 dtv[obj->tlsindex + 1] = addr; 4801 } 4802 } 4803 } 4804 4805 return (tcb); 4806 } 4807 4808 void 4809 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4810 { 4811 Elf_Addr *dtv; 4812 Elf_Addr tlsstart, tlsend; 4813 size_t post_size; 4814 size_t dtvsize, i, tls_init_align; 4815 4816 assert(tcbsize >= TLS_TCB_SIZE); 4817 tls_init_align = MAX(obj_main->tlsalign, 1); 4818 4819 /* Compute fragments sizes. */ 4820 post_size = calculate_tls_post_size(tls_init_align); 4821 4822 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4823 tlsend = (Elf_Addr)tcb + tls_static_space; 4824 4825 dtv = *(Elf_Addr **)tcb; 4826 dtvsize = dtv[1]; 4827 for (i = 0; i < dtvsize; i++) { 4828 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4829 free((void*)dtv[i+2]); 4830 } 4831 } 4832 free(dtv); 4833 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4834 } 4835 4836 #endif 4837 4838 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4839 4840 /* 4841 * Allocate Static TLS using the Variant II method. 4842 */ 4843 void * 4844 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4845 { 4846 Obj_Entry *obj; 4847 size_t size, ralign; 4848 char *tls; 4849 Elf_Addr *dtv, *olddtv; 4850 Elf_Addr segbase, oldsegbase, addr; 4851 int i; 4852 4853 ralign = tcbalign; 4854 if (tls_static_max_align > ralign) 4855 ralign = tls_static_max_align; 4856 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4857 4858 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4859 tls = malloc_aligned(size, ralign); 4860 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4861 4862 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4863 ((Elf_Addr*)segbase)[0] = segbase; 4864 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4865 4866 dtv[0] = tls_dtv_generation; 4867 dtv[1] = tls_max_index; 4868 4869 if (oldtls) { 4870 /* 4871 * Copy the static TLS block over whole. 4872 */ 4873 oldsegbase = (Elf_Addr) oldtls; 4874 memcpy((void *)(segbase - tls_static_space), 4875 (const void *)(oldsegbase - tls_static_space), 4876 tls_static_space); 4877 4878 /* 4879 * If any dynamic TLS blocks have been created tls_get_addr(), 4880 * move them over. 4881 */ 4882 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4883 for (i = 0; i < olddtv[1]; i++) { 4884 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4885 dtv[i+2] = olddtv[i+2]; 4886 olddtv[i+2] = 0; 4887 } 4888 } 4889 4890 /* 4891 * We assume that this block was the one we created with 4892 * allocate_initial_tls(). 4893 */ 4894 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4895 } else { 4896 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4897 if (obj->marker || obj->tlsoffset == 0) 4898 continue; 4899 addr = segbase - obj->tlsoffset; 4900 memset((void*) (addr + obj->tlsinitsize), 4901 0, obj->tlssize - obj->tlsinitsize); 4902 if (obj->tlsinit) 4903 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4904 dtv[obj->tlsindex + 1] = addr; 4905 } 4906 } 4907 4908 return (void*) segbase; 4909 } 4910 4911 void 4912 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4913 { 4914 Elf_Addr* dtv; 4915 size_t size, ralign; 4916 int dtvsize, i; 4917 Elf_Addr tlsstart, tlsend; 4918 4919 /* 4920 * Figure out the size of the initial TLS block so that we can 4921 * find stuff which ___tls_get_addr() allocated dynamically. 4922 */ 4923 ralign = tcbalign; 4924 if (tls_static_max_align > ralign) 4925 ralign = tls_static_max_align; 4926 size = round(tls_static_space, ralign); 4927 4928 dtv = ((Elf_Addr**)tls)[1]; 4929 dtvsize = dtv[1]; 4930 tlsend = (Elf_Addr) tls; 4931 tlsstart = tlsend - size; 4932 for (i = 0; i < dtvsize; i++) { 4933 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4934 free_aligned((void *)dtv[i + 2]); 4935 } 4936 } 4937 4938 free_aligned((void *)tlsstart); 4939 free((void*) dtv); 4940 } 4941 4942 #endif 4943 4944 /* 4945 * Allocate TLS block for module with given index. 4946 */ 4947 void * 4948 allocate_module_tls(int index) 4949 { 4950 Obj_Entry* obj; 4951 char* p; 4952 4953 TAILQ_FOREACH(obj, &obj_list, next) { 4954 if (obj->marker) 4955 continue; 4956 if (obj->tlsindex == index) 4957 break; 4958 } 4959 if (!obj) { 4960 _rtld_error("Can't find module with TLS index %d", index); 4961 rtld_die(); 4962 } 4963 4964 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4965 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4966 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4967 4968 return p; 4969 } 4970 4971 bool 4972 allocate_tls_offset(Obj_Entry *obj) 4973 { 4974 size_t off; 4975 4976 if (obj->tls_done) 4977 return true; 4978 4979 if (obj->tlssize == 0) { 4980 obj->tls_done = true; 4981 return true; 4982 } 4983 4984 if (tls_last_offset == 0) 4985 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4986 else 4987 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4988 obj->tlssize, obj->tlsalign); 4989 4990 /* 4991 * If we have already fixed the size of the static TLS block, we 4992 * must stay within that size. When allocating the static TLS, we 4993 * leave a small amount of space spare to be used for dynamically 4994 * loading modules which use static TLS. 4995 */ 4996 if (tls_static_space != 0) { 4997 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4998 return false; 4999 } else if (obj->tlsalign > tls_static_max_align) { 5000 tls_static_max_align = obj->tlsalign; 5001 } 5002 5003 tls_last_offset = obj->tlsoffset = off; 5004 tls_last_size = obj->tlssize; 5005 obj->tls_done = true; 5006 5007 return true; 5008 } 5009 5010 void 5011 free_tls_offset(Obj_Entry *obj) 5012 { 5013 5014 /* 5015 * If we were the last thing to allocate out of the static TLS 5016 * block, we give our space back to the 'allocator'. This is a 5017 * simplistic workaround to allow libGL.so.1 to be loaded and 5018 * unloaded multiple times. 5019 */ 5020 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5021 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5022 tls_last_offset -= obj->tlssize; 5023 tls_last_size = 0; 5024 } 5025 } 5026 5027 void * 5028 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5029 { 5030 void *ret; 5031 RtldLockState lockstate; 5032 5033 wlock_acquire(rtld_bind_lock, &lockstate); 5034 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5035 tcbsize, tcbalign); 5036 lock_release(rtld_bind_lock, &lockstate); 5037 return (ret); 5038 } 5039 5040 void 5041 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5042 { 5043 RtldLockState lockstate; 5044 5045 wlock_acquire(rtld_bind_lock, &lockstate); 5046 free_tls(tcb, tcbsize, tcbalign); 5047 lock_release(rtld_bind_lock, &lockstate); 5048 } 5049 5050 static void 5051 object_add_name(Obj_Entry *obj, const char *name) 5052 { 5053 Name_Entry *entry; 5054 size_t len; 5055 5056 len = strlen(name); 5057 entry = malloc(sizeof(Name_Entry) + len); 5058 5059 if (entry != NULL) { 5060 strcpy(entry->name, name); 5061 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5062 } 5063 } 5064 5065 static int 5066 object_match_name(const Obj_Entry *obj, const char *name) 5067 { 5068 Name_Entry *entry; 5069 5070 STAILQ_FOREACH(entry, &obj->names, link) { 5071 if (strcmp(name, entry->name) == 0) 5072 return (1); 5073 } 5074 return (0); 5075 } 5076 5077 static Obj_Entry * 5078 locate_dependency(const Obj_Entry *obj, const char *name) 5079 { 5080 const Objlist_Entry *entry; 5081 const Needed_Entry *needed; 5082 5083 STAILQ_FOREACH(entry, &list_main, link) { 5084 if (object_match_name(entry->obj, name)) 5085 return entry->obj; 5086 } 5087 5088 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5089 if (strcmp(obj->strtab + needed->name, name) == 0 || 5090 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5091 /* 5092 * If there is DT_NEEDED for the name we are looking for, 5093 * we are all set. Note that object might not be found if 5094 * dependency was not loaded yet, so the function can 5095 * return NULL here. This is expected and handled 5096 * properly by the caller. 5097 */ 5098 return (needed->obj); 5099 } 5100 } 5101 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5102 obj->path, name); 5103 rtld_die(); 5104 } 5105 5106 static int 5107 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5108 const Elf_Vernaux *vna) 5109 { 5110 const Elf_Verdef *vd; 5111 const char *vername; 5112 5113 vername = refobj->strtab + vna->vna_name; 5114 vd = depobj->verdef; 5115 if (vd == NULL) { 5116 _rtld_error("%s: version %s required by %s not defined", 5117 depobj->path, vername, refobj->path); 5118 return (-1); 5119 } 5120 for (;;) { 5121 if (vd->vd_version != VER_DEF_CURRENT) { 5122 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5123 depobj->path, vd->vd_version); 5124 return (-1); 5125 } 5126 if (vna->vna_hash == vd->vd_hash) { 5127 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5128 ((char *)vd + vd->vd_aux); 5129 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5130 return (0); 5131 } 5132 if (vd->vd_next == 0) 5133 break; 5134 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5135 } 5136 if (vna->vna_flags & VER_FLG_WEAK) 5137 return (0); 5138 _rtld_error("%s: version %s required by %s not found", 5139 depobj->path, vername, refobj->path); 5140 return (-1); 5141 } 5142 5143 static int 5144 rtld_verify_object_versions(Obj_Entry *obj) 5145 { 5146 const Elf_Verneed *vn; 5147 const Elf_Verdef *vd; 5148 const Elf_Verdaux *vda; 5149 const Elf_Vernaux *vna; 5150 const Obj_Entry *depobj; 5151 int maxvernum, vernum; 5152 5153 if (obj->ver_checked) 5154 return (0); 5155 obj->ver_checked = true; 5156 5157 maxvernum = 0; 5158 /* 5159 * Walk over defined and required version records and figure out 5160 * max index used by any of them. Do very basic sanity checking 5161 * while there. 5162 */ 5163 vn = obj->verneed; 5164 while (vn != NULL) { 5165 if (vn->vn_version != VER_NEED_CURRENT) { 5166 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5167 obj->path, vn->vn_version); 5168 return (-1); 5169 } 5170 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5171 for (;;) { 5172 vernum = VER_NEED_IDX(vna->vna_other); 5173 if (vernum > maxvernum) 5174 maxvernum = vernum; 5175 if (vna->vna_next == 0) 5176 break; 5177 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5178 } 5179 if (vn->vn_next == 0) 5180 break; 5181 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5182 } 5183 5184 vd = obj->verdef; 5185 while (vd != NULL) { 5186 if (vd->vd_version != VER_DEF_CURRENT) { 5187 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5188 obj->path, vd->vd_version); 5189 return (-1); 5190 } 5191 vernum = VER_DEF_IDX(vd->vd_ndx); 5192 if (vernum > maxvernum) 5193 maxvernum = vernum; 5194 if (vd->vd_next == 0) 5195 break; 5196 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5197 } 5198 5199 if (maxvernum == 0) 5200 return (0); 5201 5202 /* 5203 * Store version information in array indexable by version index. 5204 * Verify that object version requirements are satisfied along the 5205 * way. 5206 */ 5207 obj->vernum = maxvernum + 1; 5208 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5209 5210 vd = obj->verdef; 5211 while (vd != NULL) { 5212 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5213 vernum = VER_DEF_IDX(vd->vd_ndx); 5214 assert(vernum <= maxvernum); 5215 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5216 obj->vertab[vernum].hash = vd->vd_hash; 5217 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5218 obj->vertab[vernum].file = NULL; 5219 obj->vertab[vernum].flags = 0; 5220 } 5221 if (vd->vd_next == 0) 5222 break; 5223 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5224 } 5225 5226 vn = obj->verneed; 5227 while (vn != NULL) { 5228 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5229 if (depobj == NULL) 5230 return (-1); 5231 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5232 for (;;) { 5233 if (check_object_provided_version(obj, depobj, vna)) 5234 return (-1); 5235 vernum = VER_NEED_IDX(vna->vna_other); 5236 assert(vernum <= maxvernum); 5237 obj->vertab[vernum].hash = vna->vna_hash; 5238 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5239 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5240 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5241 VER_INFO_HIDDEN : 0; 5242 if (vna->vna_next == 0) 5243 break; 5244 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5245 } 5246 if (vn->vn_next == 0) 5247 break; 5248 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5249 } 5250 return 0; 5251 } 5252 5253 static int 5254 rtld_verify_versions(const Objlist *objlist) 5255 { 5256 Objlist_Entry *entry; 5257 int rc; 5258 5259 rc = 0; 5260 STAILQ_FOREACH(entry, objlist, link) { 5261 /* 5262 * Skip dummy objects or objects that have their version requirements 5263 * already checked. 5264 */ 5265 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5266 continue; 5267 if (rtld_verify_object_versions(entry->obj) == -1) { 5268 rc = -1; 5269 if (ld_tracing == NULL) 5270 break; 5271 } 5272 } 5273 if (rc == 0 || ld_tracing != NULL) 5274 rc = rtld_verify_object_versions(&obj_rtld); 5275 return rc; 5276 } 5277 5278 const Ver_Entry * 5279 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5280 { 5281 Elf_Versym vernum; 5282 5283 if (obj->vertab) { 5284 vernum = VER_NDX(obj->versyms[symnum]); 5285 if (vernum >= obj->vernum) { 5286 _rtld_error("%s: symbol %s has wrong verneed value %d", 5287 obj->path, obj->strtab + symnum, vernum); 5288 } else if (obj->vertab[vernum].hash != 0) { 5289 return &obj->vertab[vernum]; 5290 } 5291 } 5292 return NULL; 5293 } 5294 5295 int 5296 _rtld_get_stack_prot(void) 5297 { 5298 5299 return (stack_prot); 5300 } 5301 5302 int 5303 _rtld_is_dlopened(void *arg) 5304 { 5305 Obj_Entry *obj; 5306 RtldLockState lockstate; 5307 int res; 5308 5309 rlock_acquire(rtld_bind_lock, &lockstate); 5310 obj = dlcheck(arg); 5311 if (obj == NULL) 5312 obj = obj_from_addr(arg); 5313 if (obj == NULL) { 5314 _rtld_error("No shared object contains address"); 5315 lock_release(rtld_bind_lock, &lockstate); 5316 return (-1); 5317 } 5318 res = obj->dlopened ? 1 : 0; 5319 lock_release(rtld_bind_lock, &lockstate); 5320 return (res); 5321 } 5322 5323 int 5324 obj_enforce_relro(Obj_Entry *obj) 5325 { 5326 5327 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5328 PROT_READ) == -1) { 5329 _rtld_error("%s: Cannot enforce relro protection: %s", 5330 obj->path, rtld_strerror(errno)); 5331 return (-1); 5332 } 5333 return (0); 5334 } 5335 5336 static void 5337 map_stacks_exec(RtldLockState *lockstate) 5338 { 5339 void (*thr_map_stacks_exec)(void); 5340 5341 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5342 return; 5343 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5344 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5345 if (thr_map_stacks_exec != NULL) { 5346 stack_prot |= PROT_EXEC; 5347 thr_map_stacks_exec(); 5348 } 5349 } 5350 5351 void 5352 symlook_init(SymLook *dst, const char *name) 5353 { 5354 5355 bzero(dst, sizeof(*dst)); 5356 dst->name = name; 5357 dst->hash = elf_hash(name); 5358 dst->hash_gnu = gnu_hash(name); 5359 } 5360 5361 static void 5362 symlook_init_from_req(SymLook *dst, const SymLook *src) 5363 { 5364 5365 dst->name = src->name; 5366 dst->hash = src->hash; 5367 dst->hash_gnu = src->hash_gnu; 5368 dst->ventry = src->ventry; 5369 dst->flags = src->flags; 5370 dst->defobj_out = NULL; 5371 dst->sym_out = NULL; 5372 dst->lockstate = src->lockstate; 5373 } 5374 5375 static int 5376 open_binary_fd(const char *argv0, bool search_in_path) 5377 { 5378 char *pathenv, *pe, binpath[PATH_MAX]; 5379 int fd; 5380 5381 if (search_in_path && strchr(argv0, '/') == NULL) { 5382 pathenv = getenv("PATH"); 5383 if (pathenv == NULL) { 5384 _rtld_error("-p and no PATH environment variable"); 5385 rtld_die(); 5386 } 5387 pathenv = strdup(pathenv); 5388 if (pathenv == NULL) { 5389 _rtld_error("Cannot allocate memory"); 5390 rtld_die(); 5391 } 5392 fd = -1; 5393 errno = ENOENT; 5394 while ((pe = strsep(&pathenv, ":")) != NULL) { 5395 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5396 sizeof(binpath)) 5397 continue; 5398 if (binpath[0] != '\0' && 5399 strlcat(binpath, "/", sizeof(binpath)) >= 5400 sizeof(binpath)) 5401 continue; 5402 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5403 sizeof(binpath)) 5404 continue; 5405 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5406 if (fd != -1 || errno != ENOENT) 5407 break; 5408 } 5409 free(pathenv); 5410 } else { 5411 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5412 } 5413 5414 if (fd == -1) { 5415 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5416 rtld_die(); 5417 } 5418 return (fd); 5419 } 5420 5421 /* 5422 * Parse a set of command-line arguments. 5423 */ 5424 static int 5425 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5426 { 5427 const char *arg; 5428 int fd, i, j, arglen; 5429 char opt; 5430 5431 dbg("Parsing command-line arguments"); 5432 *use_pathp = false; 5433 *fdp = -1; 5434 5435 for (i = 1; i < argc; i++ ) { 5436 arg = argv[i]; 5437 dbg("argv[%d]: '%s'", i, arg); 5438 5439 /* 5440 * rtld arguments end with an explicit "--" or with the first 5441 * non-prefixed argument. 5442 */ 5443 if (strcmp(arg, "--") == 0) { 5444 i++; 5445 break; 5446 } 5447 if (arg[0] != '-') 5448 break; 5449 5450 /* 5451 * All other arguments are single-character options that can 5452 * be combined, so we need to search through `arg` for them. 5453 */ 5454 arglen = strlen(arg); 5455 for (j = 1; j < arglen; j++) { 5456 opt = arg[j]; 5457 if (opt == 'h') { 5458 print_usage(argv[0]); 5459 _exit(0); 5460 } else if (opt == 'f') { 5461 /* 5462 * -f XX can be used to specify a descriptor for the 5463 * binary named at the command line (i.e., the later 5464 * argument will specify the process name but the 5465 * descriptor is what will actually be executed) 5466 */ 5467 if (j != arglen - 1) { 5468 /* -f must be the last option in, e.g., -abcf */ 5469 _rtld_error("Invalid options: %s", arg); 5470 rtld_die(); 5471 } 5472 i++; 5473 fd = parse_integer(argv[i]); 5474 if (fd == -1) { 5475 _rtld_error("Invalid file descriptor: '%s'", 5476 argv[i]); 5477 rtld_die(); 5478 } 5479 *fdp = fd; 5480 break; 5481 } else if (opt == 'p') { 5482 *use_pathp = true; 5483 } else { 5484 _rtld_error("Invalid argument: '%s'", arg); 5485 print_usage(argv[0]); 5486 rtld_die(); 5487 } 5488 } 5489 } 5490 5491 return (i); 5492 } 5493 5494 /* 5495 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5496 */ 5497 static int 5498 parse_integer(const char *str) 5499 { 5500 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5501 const char *orig; 5502 int n; 5503 char c; 5504 5505 orig = str; 5506 n = 0; 5507 for (c = *str; c != '\0'; c = *++str) { 5508 if (c < '0' || c > '9') 5509 return (-1); 5510 5511 n *= RADIX; 5512 n += c - '0'; 5513 } 5514 5515 /* Make sure we actually parsed something. */ 5516 if (str == orig) 5517 return (-1); 5518 return (n); 5519 } 5520 5521 static void 5522 print_usage(const char *argv0) 5523 { 5524 5525 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5526 "\n" 5527 "Options:\n" 5528 " -h Display this help message\n" 5529 " -p Search in PATH for named binary\n" 5530 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5531 " -- End of RTLD options\n" 5532 " <binary> Name of process to execute\n" 5533 " <args> Arguments to the executed process\n", argv0); 5534 } 5535 5536 /* 5537 * Overrides for libc_pic-provided functions. 5538 */ 5539 5540 int 5541 __getosreldate(void) 5542 { 5543 size_t len; 5544 int oid[2]; 5545 int error, osrel; 5546 5547 if (osreldate != 0) 5548 return (osreldate); 5549 5550 oid[0] = CTL_KERN; 5551 oid[1] = KERN_OSRELDATE; 5552 osrel = 0; 5553 len = sizeof(osrel); 5554 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5555 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5556 osreldate = osrel; 5557 return (osreldate); 5558 } 5559 5560 void 5561 exit(int status) 5562 { 5563 5564 _exit(status); 5565 } 5566 5567 void (*__cleanup)(void); 5568 int __isthreaded = 0; 5569 int _thread_autoinit_dummy_decl = 1; 5570 5571 /* 5572 * No unresolved symbols for rtld. 5573 */ 5574 void 5575 __pthread_cxa_finalize(struct dl_phdr_info *a) 5576 { 5577 } 5578 5579 const char * 5580 rtld_strerror(int errnum) 5581 { 5582 5583 if (errnum < 0 || errnum >= sys_nerr) 5584 return ("Unknown error"); 5585 return (sys_errlist[errnum]); 5586 } 5587