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 int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 107 static void linkmap_add(Obj_Entry *); 108 static void linkmap_delete(Obj_Entry *); 109 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 110 static void unload_filtees(Obj_Entry *, RtldLockState *); 111 static int load_needed_objects(Obj_Entry *, int); 112 static int load_preload_objects(void); 113 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 114 static void map_stacks_exec(RtldLockState *); 115 static int obj_disable_relro(Obj_Entry *); 116 static int obj_enforce_relro(Obj_Entry *); 117 static Obj_Entry *obj_from_addr(const void *); 118 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 119 static void objlist_call_init(Objlist *, RtldLockState *); 120 static void objlist_clear(Objlist *); 121 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 122 static void objlist_init(Objlist *); 123 static void objlist_push_head(Objlist *, Obj_Entry *); 124 static void objlist_push_tail(Objlist *, Obj_Entry *); 125 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 126 static void objlist_remove(Objlist *, Obj_Entry *); 127 static int open_binary_fd(const char *argv0, bool search_in_path); 128 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 129 static int parse_integer(const char *); 130 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 131 static void print_usage(const char *argv0); 132 static void release_object(Obj_Entry *); 133 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 134 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 135 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 136 int flags, RtldLockState *lockstate); 137 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 138 RtldLockState *); 139 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 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 if (!obj_main->crt_no_init) { 717 /* 718 * Make sure we don't call the main program's init and fini 719 * functions for binaries linked with old crt1 which calls 720 * _init itself. 721 */ 722 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 723 obj_main->preinit_array = obj_main->init_array = 724 obj_main->fini_array = (Elf_Addr)NULL; 725 } 726 727 /* 728 * Execute MD initializers required before we call the objects' 729 * init functions. 730 */ 731 pre_init(); 732 733 wlock_acquire(rtld_bind_lock, &lockstate); 734 735 dbg("resolving ifuncs"); 736 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 737 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 738 rtld_die(); 739 740 if (obj_main->crt_no_init) 741 preinit_main(); 742 objlist_call_init(&initlist, &lockstate); 743 _r_debug_postinit(&obj_main->linkmap); 744 objlist_clear(&initlist); 745 dbg("loading filtees"); 746 TAILQ_FOREACH(obj, &obj_list, next) { 747 if (obj->marker) 748 continue; 749 if (ld_loadfltr || obj->z_loadfltr) 750 load_filtees(obj, 0, &lockstate); 751 } 752 753 dbg("enforcing main obj relro"); 754 if (obj_enforce_relro(obj_main) == -1) 755 rtld_die(); 756 757 lock_release(rtld_bind_lock, &lockstate); 758 759 dbg("transferring control to program entry point = %p", obj_main->entry); 760 761 /* Return the exit procedure and the program entry point. */ 762 *exit_proc = rtld_exit; 763 *objp = obj_main; 764 return (func_ptr_type) obj_main->entry; 765 } 766 767 void * 768 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 769 { 770 void *ptr; 771 Elf_Addr target; 772 773 ptr = (void *)make_function_pointer(def, obj); 774 target = call_ifunc_resolver(ptr); 775 return ((void *)target); 776 } 777 778 /* 779 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 780 * Changes to this function should be applied there as well. 781 */ 782 Elf_Addr 783 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 784 { 785 const Elf_Rel *rel; 786 const Elf_Sym *def; 787 const Obj_Entry *defobj; 788 Elf_Addr *where; 789 Elf_Addr target; 790 RtldLockState lockstate; 791 792 rlock_acquire(rtld_bind_lock, &lockstate); 793 if (sigsetjmp(lockstate.env, 0) != 0) 794 lock_upgrade(rtld_bind_lock, &lockstate); 795 if (obj->pltrel) 796 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 797 else 798 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 799 800 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 801 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 802 NULL, &lockstate); 803 if (def == NULL) 804 rtld_die(); 805 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 806 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 807 else 808 target = (Elf_Addr)(defobj->relocbase + def->st_value); 809 810 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 811 defobj->strtab + def->st_name, basename(obj->path), 812 (void *)target, basename(defobj->path)); 813 814 /* 815 * Write the new contents for the jmpslot. Note that depending on 816 * architecture, the value which we need to return back to the 817 * lazy binding trampoline may or may not be the target 818 * address. The value returned from reloc_jmpslot() is the value 819 * that the trampoline needs. 820 */ 821 target = reloc_jmpslot(where, target, defobj, obj, rel); 822 lock_release(rtld_bind_lock, &lockstate); 823 return target; 824 } 825 826 /* 827 * Error reporting function. Use it like printf. If formats the message 828 * into a buffer, and sets things up so that the next call to dlerror() 829 * will return the message. 830 */ 831 void 832 _rtld_error(const char *fmt, ...) 833 { 834 static char buf[512]; 835 va_list ap; 836 837 va_start(ap, fmt); 838 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 839 error_message = buf; 840 va_end(ap); 841 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 842 } 843 844 /* 845 * Return a dynamically-allocated copy of the current error message, if any. 846 */ 847 static char * 848 errmsg_save(void) 849 { 850 return error_message == NULL ? NULL : xstrdup(error_message); 851 } 852 853 /* 854 * Restore the current error message from a copy which was previously saved 855 * by errmsg_save(). The copy is freed. 856 */ 857 static void 858 errmsg_restore(char *saved_msg) 859 { 860 if (saved_msg == NULL) 861 error_message = NULL; 862 else { 863 _rtld_error("%s", saved_msg); 864 free(saved_msg); 865 } 866 } 867 868 static const char * 869 basename(const char *name) 870 { 871 const char *p = strrchr(name, '/'); 872 return p != NULL ? p + 1 : name; 873 } 874 875 static struct utsname uts; 876 877 static char * 878 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 879 const char *subst, bool may_free) 880 { 881 char *p, *p1, *res, *resp; 882 int subst_len, kw_len, subst_count, old_len, new_len; 883 884 kw_len = strlen(kw); 885 886 /* 887 * First, count the number of the keyword occurrences, to 888 * preallocate the final string. 889 */ 890 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 891 p1 = strstr(p, kw); 892 if (p1 == NULL) 893 break; 894 } 895 896 /* 897 * If the keyword is not found, just return. 898 * 899 * Return non-substituted string if resolution failed. We 900 * cannot do anything more reasonable, the failure mode of the 901 * caller is unresolved library anyway. 902 */ 903 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 904 return (may_free ? real : xstrdup(real)); 905 if (obj != NULL) 906 subst = obj->origin_path; 907 908 /* 909 * There is indeed something to substitute. Calculate the 910 * length of the resulting string, and allocate it. 911 */ 912 subst_len = strlen(subst); 913 old_len = strlen(real); 914 new_len = old_len + (subst_len - kw_len) * subst_count; 915 res = xmalloc(new_len + 1); 916 917 /* 918 * Now, execute the substitution loop. 919 */ 920 for (p = real, resp = res, *resp = '\0';;) { 921 p1 = strstr(p, kw); 922 if (p1 != NULL) { 923 /* Copy the prefix before keyword. */ 924 memcpy(resp, p, p1 - p); 925 resp += p1 - p; 926 /* Keyword replacement. */ 927 memcpy(resp, subst, subst_len); 928 resp += subst_len; 929 *resp = '\0'; 930 p = p1 + kw_len; 931 } else 932 break; 933 } 934 935 /* Copy to the end of string and finish. */ 936 strcat(resp, p); 937 if (may_free) 938 free(real); 939 return (res); 940 } 941 942 static char * 943 origin_subst(Obj_Entry *obj, char *real) 944 { 945 char *res1, *res2, *res3, *res4; 946 947 if (obj == NULL || !trust) 948 return (xstrdup(real)); 949 if (uts.sysname[0] == '\0') { 950 if (uname(&uts) != 0) { 951 _rtld_error("utsname failed: %d", errno); 952 return (NULL); 953 } 954 } 955 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 956 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 957 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 958 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 959 return (res4); 960 } 961 962 void 963 rtld_die(void) 964 { 965 const char *msg = dlerror(); 966 967 if (msg == NULL) 968 msg = "Fatal error"; 969 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 970 rtld_fdputstr(STDERR_FILENO, msg); 971 rtld_fdputchar(STDERR_FILENO, '\n'); 972 _exit(1); 973 } 974 975 /* 976 * Process a shared object's DYNAMIC section, and save the important 977 * information in its Obj_Entry structure. 978 */ 979 static void 980 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 981 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 982 { 983 const Elf_Dyn *dynp; 984 Needed_Entry **needed_tail = &obj->needed; 985 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 986 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 987 const Elf_Hashelt *hashtab; 988 const Elf32_Word *hashval; 989 Elf32_Word bkt, nmaskwords; 990 int bloom_size32; 991 int plttype = DT_REL; 992 993 *dyn_rpath = NULL; 994 *dyn_soname = NULL; 995 *dyn_runpath = NULL; 996 997 obj->bind_now = false; 998 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 999 switch (dynp->d_tag) { 1000 1001 case DT_REL: 1002 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1003 break; 1004 1005 case DT_RELSZ: 1006 obj->relsize = dynp->d_un.d_val; 1007 break; 1008 1009 case DT_RELENT: 1010 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1011 break; 1012 1013 case DT_JMPREL: 1014 obj->pltrel = (const Elf_Rel *) 1015 (obj->relocbase + dynp->d_un.d_ptr); 1016 break; 1017 1018 case DT_PLTRELSZ: 1019 obj->pltrelsize = dynp->d_un.d_val; 1020 break; 1021 1022 case DT_RELA: 1023 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1024 break; 1025 1026 case DT_RELASZ: 1027 obj->relasize = dynp->d_un.d_val; 1028 break; 1029 1030 case DT_RELAENT: 1031 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1032 break; 1033 1034 case DT_PLTREL: 1035 plttype = dynp->d_un.d_val; 1036 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1037 break; 1038 1039 case DT_SYMTAB: 1040 obj->symtab = (const Elf_Sym *) 1041 (obj->relocbase + dynp->d_un.d_ptr); 1042 break; 1043 1044 case DT_SYMENT: 1045 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1046 break; 1047 1048 case DT_STRTAB: 1049 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1050 break; 1051 1052 case DT_STRSZ: 1053 obj->strsize = dynp->d_un.d_val; 1054 break; 1055 1056 case DT_VERNEED: 1057 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1058 dynp->d_un.d_val); 1059 break; 1060 1061 case DT_VERNEEDNUM: 1062 obj->verneednum = dynp->d_un.d_val; 1063 break; 1064 1065 case DT_VERDEF: 1066 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1067 dynp->d_un.d_val); 1068 break; 1069 1070 case DT_VERDEFNUM: 1071 obj->verdefnum = dynp->d_un.d_val; 1072 break; 1073 1074 case DT_VERSYM: 1075 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1076 dynp->d_un.d_val); 1077 break; 1078 1079 case DT_HASH: 1080 { 1081 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1082 dynp->d_un.d_ptr); 1083 obj->nbuckets = hashtab[0]; 1084 obj->nchains = hashtab[1]; 1085 obj->buckets = hashtab + 2; 1086 obj->chains = obj->buckets + obj->nbuckets; 1087 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1088 obj->buckets != NULL; 1089 } 1090 break; 1091 1092 case DT_GNU_HASH: 1093 { 1094 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1095 dynp->d_un.d_ptr); 1096 obj->nbuckets_gnu = hashtab[0]; 1097 obj->symndx_gnu = hashtab[1]; 1098 nmaskwords = hashtab[2]; 1099 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1100 obj->maskwords_bm_gnu = nmaskwords - 1; 1101 obj->shift2_gnu = hashtab[3]; 1102 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1103 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1104 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1105 obj->symndx_gnu; 1106 /* Number of bitmask words is required to be power of 2 */ 1107 obj->valid_hash_gnu = powerof2(nmaskwords) && 1108 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1109 } 1110 break; 1111 1112 case DT_NEEDED: 1113 if (!obj->rtld) { 1114 Needed_Entry *nep = NEW(Needed_Entry); 1115 nep->name = dynp->d_un.d_val; 1116 nep->obj = NULL; 1117 nep->next = NULL; 1118 1119 *needed_tail = nep; 1120 needed_tail = &nep->next; 1121 } 1122 break; 1123 1124 case DT_FILTER: 1125 if (!obj->rtld) { 1126 Needed_Entry *nep = NEW(Needed_Entry); 1127 nep->name = dynp->d_un.d_val; 1128 nep->obj = NULL; 1129 nep->next = NULL; 1130 1131 *needed_filtees_tail = nep; 1132 needed_filtees_tail = &nep->next; 1133 } 1134 break; 1135 1136 case DT_AUXILIARY: 1137 if (!obj->rtld) { 1138 Needed_Entry *nep = NEW(Needed_Entry); 1139 nep->name = dynp->d_un.d_val; 1140 nep->obj = NULL; 1141 nep->next = NULL; 1142 1143 *needed_aux_filtees_tail = nep; 1144 needed_aux_filtees_tail = &nep->next; 1145 } 1146 break; 1147 1148 case DT_PLTGOT: 1149 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1150 break; 1151 1152 case DT_TEXTREL: 1153 obj->textrel = true; 1154 break; 1155 1156 case DT_SYMBOLIC: 1157 obj->symbolic = true; 1158 break; 1159 1160 case DT_RPATH: 1161 /* 1162 * We have to wait until later to process this, because we 1163 * might not have gotten the address of the string table yet. 1164 */ 1165 *dyn_rpath = dynp; 1166 break; 1167 1168 case DT_SONAME: 1169 *dyn_soname = dynp; 1170 break; 1171 1172 case DT_RUNPATH: 1173 *dyn_runpath = dynp; 1174 break; 1175 1176 case DT_INIT: 1177 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1178 break; 1179 1180 case DT_PREINIT_ARRAY: 1181 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1182 break; 1183 1184 case DT_PREINIT_ARRAYSZ: 1185 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1186 break; 1187 1188 case DT_INIT_ARRAY: 1189 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1190 break; 1191 1192 case DT_INIT_ARRAYSZ: 1193 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1194 break; 1195 1196 case DT_FINI: 1197 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1198 break; 1199 1200 case DT_FINI_ARRAY: 1201 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1202 break; 1203 1204 case DT_FINI_ARRAYSZ: 1205 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1206 break; 1207 1208 /* 1209 * Don't process DT_DEBUG on MIPS as the dynamic section 1210 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1211 */ 1212 1213 #ifndef __mips__ 1214 case DT_DEBUG: 1215 if (!early) 1216 dbg("Filling in DT_DEBUG entry"); 1217 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1218 break; 1219 #endif 1220 1221 case DT_FLAGS: 1222 if (dynp->d_un.d_val & DF_ORIGIN) 1223 obj->z_origin = true; 1224 if (dynp->d_un.d_val & DF_SYMBOLIC) 1225 obj->symbolic = true; 1226 if (dynp->d_un.d_val & DF_TEXTREL) 1227 obj->textrel = true; 1228 if (dynp->d_un.d_val & DF_BIND_NOW) 1229 obj->bind_now = true; 1230 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1231 ;*/ 1232 break; 1233 #ifdef __mips__ 1234 case DT_MIPS_LOCAL_GOTNO: 1235 obj->local_gotno = dynp->d_un.d_val; 1236 break; 1237 1238 case DT_MIPS_SYMTABNO: 1239 obj->symtabno = dynp->d_un.d_val; 1240 break; 1241 1242 case DT_MIPS_GOTSYM: 1243 obj->gotsym = dynp->d_un.d_val; 1244 break; 1245 1246 case DT_MIPS_RLD_MAP: 1247 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1248 break; 1249 1250 case DT_MIPS_PLTGOT: 1251 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1252 dynp->d_un.d_ptr); 1253 break; 1254 1255 #endif 1256 1257 #ifdef __powerpc64__ 1258 case DT_PPC64_GLINK: 1259 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1260 break; 1261 #endif 1262 1263 case DT_FLAGS_1: 1264 if (dynp->d_un.d_val & DF_1_NOOPEN) 1265 obj->z_noopen = true; 1266 if (dynp->d_un.d_val & DF_1_ORIGIN) 1267 obj->z_origin = true; 1268 if (dynp->d_un.d_val & DF_1_GLOBAL) 1269 obj->z_global = true; 1270 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1271 obj->bind_now = true; 1272 if (dynp->d_un.d_val & DF_1_NODELETE) 1273 obj->z_nodelete = true; 1274 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1275 obj->z_loadfltr = true; 1276 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1277 obj->z_interpose = true; 1278 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1279 obj->z_nodeflib = true; 1280 break; 1281 1282 default: 1283 if (!early) { 1284 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1285 (long)dynp->d_tag); 1286 } 1287 break; 1288 } 1289 } 1290 1291 obj->traced = false; 1292 1293 if (plttype == DT_RELA) { 1294 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1295 obj->pltrel = NULL; 1296 obj->pltrelasize = obj->pltrelsize; 1297 obj->pltrelsize = 0; 1298 } 1299 1300 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1301 if (obj->valid_hash_sysv) 1302 obj->dynsymcount = obj->nchains; 1303 else if (obj->valid_hash_gnu) { 1304 obj->dynsymcount = 0; 1305 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1306 if (obj->buckets_gnu[bkt] == 0) 1307 continue; 1308 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1309 do 1310 obj->dynsymcount++; 1311 while ((*hashval++ & 1u) == 0); 1312 } 1313 obj->dynsymcount += obj->symndx_gnu; 1314 } 1315 } 1316 1317 static bool 1318 obj_resolve_origin(Obj_Entry *obj) 1319 { 1320 1321 if (obj->origin_path != NULL) 1322 return (true); 1323 obj->origin_path = xmalloc(PATH_MAX); 1324 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1325 } 1326 1327 static void 1328 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1329 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1330 { 1331 1332 if (obj->z_origin && !obj_resolve_origin(obj)) 1333 rtld_die(); 1334 1335 if (dyn_runpath != NULL) { 1336 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1337 obj->runpath = origin_subst(obj, obj->runpath); 1338 } else if (dyn_rpath != NULL) { 1339 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1340 obj->rpath = origin_subst(obj, obj->rpath); 1341 } 1342 if (dyn_soname != NULL) 1343 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1344 } 1345 1346 static void 1347 digest_dynamic(Obj_Entry *obj, int early) 1348 { 1349 const Elf_Dyn *dyn_rpath; 1350 const Elf_Dyn *dyn_soname; 1351 const Elf_Dyn *dyn_runpath; 1352 1353 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1354 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1355 } 1356 1357 /* 1358 * Process a shared object's program header. This is used only for the 1359 * main program, when the kernel has already loaded the main program 1360 * into memory before calling the dynamic linker. It creates and 1361 * returns an Obj_Entry structure. 1362 */ 1363 static Obj_Entry * 1364 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1365 { 1366 Obj_Entry *obj; 1367 const Elf_Phdr *phlimit = phdr + phnum; 1368 const Elf_Phdr *ph; 1369 Elf_Addr note_start, note_end; 1370 int nsegs = 0; 1371 1372 obj = obj_new(); 1373 for (ph = phdr; ph < phlimit; ph++) { 1374 if (ph->p_type != PT_PHDR) 1375 continue; 1376 1377 obj->phdr = phdr; 1378 obj->phsize = ph->p_memsz; 1379 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1380 break; 1381 } 1382 1383 obj->stack_flags = PF_X | PF_R | PF_W; 1384 1385 for (ph = phdr; ph < phlimit; ph++) { 1386 switch (ph->p_type) { 1387 1388 case PT_INTERP: 1389 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1390 break; 1391 1392 case PT_LOAD: 1393 if (nsegs == 0) { /* First load segment */ 1394 obj->vaddrbase = trunc_page(ph->p_vaddr); 1395 obj->mapbase = obj->vaddrbase + obj->relocbase; 1396 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1397 obj->vaddrbase; 1398 } else { /* Last load segment */ 1399 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1400 obj->vaddrbase; 1401 } 1402 nsegs++; 1403 break; 1404 1405 case PT_DYNAMIC: 1406 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1407 break; 1408 1409 case PT_TLS: 1410 obj->tlsindex = 1; 1411 obj->tlssize = ph->p_memsz; 1412 obj->tlsalign = ph->p_align; 1413 obj->tlsinitsize = ph->p_filesz; 1414 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1415 break; 1416 1417 case PT_GNU_STACK: 1418 obj->stack_flags = ph->p_flags; 1419 break; 1420 1421 case PT_GNU_RELRO: 1422 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1423 obj->relro_size = round_page(ph->p_memsz); 1424 break; 1425 1426 case PT_NOTE: 1427 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1428 note_end = note_start + ph->p_filesz; 1429 digest_notes(obj, note_start, note_end); 1430 break; 1431 } 1432 } 1433 if (nsegs < 1) { 1434 _rtld_error("%s: too few PT_LOAD segments", path); 1435 return NULL; 1436 } 1437 1438 obj->entry = entry; 1439 return obj; 1440 } 1441 1442 void 1443 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1444 { 1445 const Elf_Note *note; 1446 const char *note_name; 1447 uintptr_t p; 1448 1449 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1450 note = (const Elf_Note *)((const char *)(note + 1) + 1451 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1452 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1453 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1454 note->n_descsz != sizeof(int32_t)) 1455 continue; 1456 if (note->n_type != NT_FREEBSD_ABI_TAG && 1457 note->n_type != NT_FREEBSD_FEATURE_CTL && 1458 note->n_type != NT_FREEBSD_NOINIT_TAG) 1459 continue; 1460 note_name = (const char *)(note + 1); 1461 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1462 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1463 continue; 1464 switch (note->n_type) { 1465 case NT_FREEBSD_ABI_TAG: 1466 /* FreeBSD osrel note */ 1467 p = (uintptr_t)(note + 1); 1468 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1469 obj->osrel = *(const int32_t *)(p); 1470 dbg("note osrel %d", obj->osrel); 1471 break; 1472 case NT_FREEBSD_FEATURE_CTL: 1473 /* FreeBSD ABI feature control note */ 1474 p = (uintptr_t)(note + 1); 1475 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1476 obj->fctl0 = *(const uint32_t *)(p); 1477 dbg("note fctl0 %#x", obj->fctl0); 1478 break; 1479 case NT_FREEBSD_NOINIT_TAG: 1480 /* FreeBSD 'crt does not call init' note */ 1481 obj->crt_no_init = true; 1482 dbg("note crt_no_init"); 1483 break; 1484 } 1485 } 1486 } 1487 1488 static Obj_Entry * 1489 dlcheck(void *handle) 1490 { 1491 Obj_Entry *obj; 1492 1493 TAILQ_FOREACH(obj, &obj_list, next) { 1494 if (obj == (Obj_Entry *) handle) 1495 break; 1496 } 1497 1498 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1499 _rtld_error("Invalid shared object handle %p", handle); 1500 return NULL; 1501 } 1502 return obj; 1503 } 1504 1505 /* 1506 * If the given object is already in the donelist, return true. Otherwise 1507 * add the object to the list and return false. 1508 */ 1509 static bool 1510 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1511 { 1512 unsigned int i; 1513 1514 for (i = 0; i < dlp->num_used; i++) 1515 if (dlp->objs[i] == obj) 1516 return true; 1517 /* 1518 * Our donelist allocation should always be sufficient. But if 1519 * our threads locking isn't working properly, more shared objects 1520 * could have been loaded since we allocated the list. That should 1521 * never happen, but we'll handle it properly just in case it does. 1522 */ 1523 if (dlp->num_used < dlp->num_alloc) 1524 dlp->objs[dlp->num_used++] = obj; 1525 return false; 1526 } 1527 1528 /* 1529 * Hash function for symbol table lookup. Don't even think about changing 1530 * this. It is specified by the System V ABI. 1531 */ 1532 unsigned long 1533 elf_hash(const char *name) 1534 { 1535 const unsigned char *p = (const unsigned char *) name; 1536 unsigned long h = 0; 1537 unsigned long g; 1538 1539 while (*p != '\0') { 1540 h = (h << 4) + *p++; 1541 if ((g = h & 0xf0000000) != 0) 1542 h ^= g >> 24; 1543 h &= ~g; 1544 } 1545 return h; 1546 } 1547 1548 /* 1549 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1550 * unsigned in case it's implemented with a wider type. 1551 */ 1552 static uint32_t 1553 gnu_hash(const char *s) 1554 { 1555 uint32_t h; 1556 unsigned char c; 1557 1558 h = 5381; 1559 for (c = *s; c != '\0'; c = *++s) 1560 h = h * 33 + c; 1561 return (h & 0xffffffff); 1562 } 1563 1564 1565 /* 1566 * Find the library with the given name, and return its full pathname. 1567 * The returned string is dynamically allocated. Generates an error 1568 * message and returns NULL if the library cannot be found. 1569 * 1570 * If the second argument is non-NULL, then it refers to an already- 1571 * loaded shared object, whose library search path will be searched. 1572 * 1573 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1574 * descriptor (which is close-on-exec) will be passed out via the third 1575 * argument. 1576 * 1577 * The search order is: 1578 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1579 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1580 * LD_LIBRARY_PATH 1581 * DT_RUNPATH in the referencing file 1582 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1583 * from list) 1584 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1585 * 1586 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1587 */ 1588 static char * 1589 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1590 { 1591 char *name, *pathname, *refobj_path; 1592 bool nodeflib, objgiven; 1593 1594 objgiven = refobj != NULL; 1595 1596 if (libmap_disable || !objgiven || 1597 (name = lm_find(refobj->path, xname)) == NULL) 1598 name = (char *)xname; 1599 1600 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1601 if (name[0] != '/' && !trust) { 1602 _rtld_error("Absolute pathname required " 1603 "for shared object \"%s\"", name); 1604 return (NULL); 1605 } 1606 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1607 __DECONST(char *, name))); 1608 } 1609 1610 dbg(" Searching for \"%s\"", name); 1611 refobj_path = objgiven ? refobj->path : NULL; 1612 1613 /* 1614 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1615 * back to pre-conforming behaviour if user requested so with 1616 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1617 * nodeflib. 1618 */ 1619 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1620 pathname = search_library_path(name, ld_library_path, 1621 refobj_path, fdp); 1622 if (pathname != NULL) 1623 return (pathname); 1624 if (refobj != NULL) { 1625 pathname = search_library_path(name, refobj->rpath, 1626 refobj_path, fdp); 1627 if (pathname != NULL) 1628 return (pathname); 1629 } 1630 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1631 if (pathname != NULL) 1632 return (pathname); 1633 pathname = search_library_path(name, gethints(false), 1634 refobj_path, fdp); 1635 if (pathname != NULL) 1636 return (pathname); 1637 pathname = search_library_path(name, ld_standard_library_path, 1638 refobj_path, fdp); 1639 if (pathname != NULL) 1640 return (pathname); 1641 } else { 1642 nodeflib = objgiven ? refobj->z_nodeflib : false; 1643 if (objgiven) { 1644 pathname = search_library_path(name, refobj->rpath, 1645 refobj->path, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 } 1649 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1650 pathname = search_library_path(name, obj_main->rpath, 1651 refobj_path, fdp); 1652 if (pathname != NULL) 1653 return (pathname); 1654 } 1655 pathname = search_library_path(name, ld_library_path, 1656 refobj_path, fdp); 1657 if (pathname != NULL) 1658 return (pathname); 1659 if (objgiven) { 1660 pathname = search_library_path(name, refobj->runpath, 1661 refobj_path, fdp); 1662 if (pathname != NULL) 1663 return (pathname); 1664 } 1665 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 pathname = search_library_path(name, gethints(nodeflib), 1669 refobj_path, fdp); 1670 if (pathname != NULL) 1671 return (pathname); 1672 if (objgiven && !nodeflib) { 1673 pathname = search_library_path(name, 1674 ld_standard_library_path, refobj_path, fdp); 1675 if (pathname != NULL) 1676 return (pathname); 1677 } 1678 } 1679 1680 if (objgiven && refobj->path != NULL) { 1681 _rtld_error("Shared object \"%s\" not found, " 1682 "required by \"%s\"", name, basename(refobj->path)); 1683 } else { 1684 _rtld_error("Shared object \"%s\" not found", name); 1685 } 1686 return (NULL); 1687 } 1688 1689 /* 1690 * Given a symbol number in a referencing object, find the corresponding 1691 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1692 * no definition was found. Returns a pointer to the Obj_Entry of the 1693 * defining object via the reference parameter DEFOBJ_OUT. 1694 */ 1695 const Elf_Sym * 1696 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1697 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1698 RtldLockState *lockstate) 1699 { 1700 const Elf_Sym *ref; 1701 const Elf_Sym *def; 1702 const Obj_Entry *defobj; 1703 const Ver_Entry *ve; 1704 SymLook req; 1705 const char *name; 1706 int res; 1707 1708 /* 1709 * If we have already found this symbol, get the information from 1710 * the cache. 1711 */ 1712 if (symnum >= refobj->dynsymcount) 1713 return NULL; /* Bad object */ 1714 if (cache != NULL && cache[symnum].sym != NULL) { 1715 *defobj_out = cache[symnum].obj; 1716 return cache[symnum].sym; 1717 } 1718 1719 ref = refobj->symtab + symnum; 1720 name = refobj->strtab + ref->st_name; 1721 def = NULL; 1722 defobj = NULL; 1723 ve = NULL; 1724 1725 /* 1726 * We don't have to do a full scale lookup if the symbol is local. 1727 * We know it will bind to the instance in this load module; to 1728 * which we already have a pointer (ie ref). By not doing a lookup, 1729 * we not only improve performance, but it also avoids unresolvable 1730 * symbols when local symbols are not in the hash table. This has 1731 * been seen with the ia64 toolchain. 1732 */ 1733 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1734 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1735 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1736 symnum); 1737 } 1738 symlook_init(&req, name); 1739 req.flags = flags; 1740 ve = req.ventry = fetch_ventry(refobj, symnum); 1741 req.lockstate = lockstate; 1742 res = symlook_default(&req, refobj); 1743 if (res == 0) { 1744 def = req.sym_out; 1745 defobj = req.defobj_out; 1746 } 1747 } else { 1748 def = ref; 1749 defobj = refobj; 1750 } 1751 1752 /* 1753 * If we found no definition and the reference is weak, treat the 1754 * symbol as having the value zero. 1755 */ 1756 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1757 def = &sym_zero; 1758 defobj = obj_main; 1759 } 1760 1761 if (def != NULL) { 1762 *defobj_out = defobj; 1763 /* Record the information in the cache to avoid subsequent lookups. */ 1764 if (cache != NULL) { 1765 cache[symnum].sym = def; 1766 cache[symnum].obj = defobj; 1767 } 1768 } else { 1769 if (refobj != &obj_rtld) 1770 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1771 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1772 } 1773 return def; 1774 } 1775 1776 /* 1777 * Return the search path from the ldconfig hints file, reading it if 1778 * necessary. If nostdlib is true, then the default search paths are 1779 * not added to result. 1780 * 1781 * Returns NULL if there are problems with the hints file, 1782 * or if the search path there is empty. 1783 */ 1784 static const char * 1785 gethints(bool nostdlib) 1786 { 1787 static char *hints, *filtered_path; 1788 static struct elfhints_hdr hdr; 1789 struct fill_search_info_args sargs, hargs; 1790 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1791 struct dl_serpath *SLPpath, *hintpath; 1792 char *p; 1793 struct stat hint_stat; 1794 unsigned int SLPndx, hintndx, fndx, fcount; 1795 int fd; 1796 size_t flen; 1797 uint32_t dl; 1798 bool skip; 1799 1800 /* First call, read the hints file */ 1801 if (hints == NULL) { 1802 /* Keep from trying again in case the hints file is bad. */ 1803 hints = ""; 1804 1805 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1806 return (NULL); 1807 1808 /* 1809 * Check of hdr.dirlistlen value against type limit 1810 * intends to pacify static analyzers. Further 1811 * paranoia leads to checks that dirlist is fully 1812 * contained in the file range. 1813 */ 1814 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1815 hdr.magic != ELFHINTS_MAGIC || 1816 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1817 fstat(fd, &hint_stat) == -1) { 1818 cleanup1: 1819 close(fd); 1820 hdr.dirlistlen = 0; 1821 return (NULL); 1822 } 1823 dl = hdr.strtab; 1824 if (dl + hdr.dirlist < dl) 1825 goto cleanup1; 1826 dl += hdr.dirlist; 1827 if (dl + hdr.dirlistlen < dl) 1828 goto cleanup1; 1829 dl += hdr.dirlistlen; 1830 if (dl > hint_stat.st_size) 1831 goto cleanup1; 1832 p = xmalloc(hdr.dirlistlen + 1); 1833 if (pread(fd, p, hdr.dirlistlen + 1, 1834 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1835 p[hdr.dirlistlen] != '\0') { 1836 free(p); 1837 goto cleanup1; 1838 } 1839 hints = p; 1840 close(fd); 1841 } 1842 1843 /* 1844 * If caller agreed to receive list which includes the default 1845 * paths, we are done. Otherwise, if we still did not 1846 * calculated filtered result, do it now. 1847 */ 1848 if (!nostdlib) 1849 return (hints[0] != '\0' ? hints : NULL); 1850 if (filtered_path != NULL) 1851 goto filt_ret; 1852 1853 /* 1854 * Obtain the list of all configured search paths, and the 1855 * list of the default paths. 1856 * 1857 * First estimate the size of the results. 1858 */ 1859 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1860 smeta.dls_cnt = 0; 1861 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1862 hmeta.dls_cnt = 0; 1863 1864 sargs.request = RTLD_DI_SERINFOSIZE; 1865 sargs.serinfo = &smeta; 1866 hargs.request = RTLD_DI_SERINFOSIZE; 1867 hargs.serinfo = &hmeta; 1868 1869 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1870 &sargs); 1871 path_enumerate(hints, fill_search_info, NULL, &hargs); 1872 1873 SLPinfo = xmalloc(smeta.dls_size); 1874 hintinfo = xmalloc(hmeta.dls_size); 1875 1876 /* 1877 * Next fetch both sets of paths. 1878 */ 1879 sargs.request = RTLD_DI_SERINFO; 1880 sargs.serinfo = SLPinfo; 1881 sargs.serpath = &SLPinfo->dls_serpath[0]; 1882 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1883 1884 hargs.request = RTLD_DI_SERINFO; 1885 hargs.serinfo = hintinfo; 1886 hargs.serpath = &hintinfo->dls_serpath[0]; 1887 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1888 1889 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1890 &sargs); 1891 path_enumerate(hints, fill_search_info, NULL, &hargs); 1892 1893 /* 1894 * Now calculate the difference between two sets, by excluding 1895 * standard paths from the full set. 1896 */ 1897 fndx = 0; 1898 fcount = 0; 1899 filtered_path = xmalloc(hdr.dirlistlen + 1); 1900 hintpath = &hintinfo->dls_serpath[0]; 1901 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1902 skip = false; 1903 SLPpath = &SLPinfo->dls_serpath[0]; 1904 /* 1905 * Check each standard path against current. 1906 */ 1907 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1908 /* matched, skip the path */ 1909 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1910 skip = true; 1911 break; 1912 } 1913 } 1914 if (skip) 1915 continue; 1916 /* 1917 * Not matched against any standard path, add the path 1918 * to result. Separate consequtive paths with ':'. 1919 */ 1920 if (fcount > 0) { 1921 filtered_path[fndx] = ':'; 1922 fndx++; 1923 } 1924 fcount++; 1925 flen = strlen(hintpath->dls_name); 1926 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1927 fndx += flen; 1928 } 1929 filtered_path[fndx] = '\0'; 1930 1931 free(SLPinfo); 1932 free(hintinfo); 1933 1934 filt_ret: 1935 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1936 } 1937 1938 static void 1939 init_dag(Obj_Entry *root) 1940 { 1941 const Needed_Entry *needed; 1942 const Objlist_Entry *elm; 1943 DoneList donelist; 1944 1945 if (root->dag_inited) 1946 return; 1947 donelist_init(&donelist); 1948 1949 /* Root object belongs to own DAG. */ 1950 objlist_push_tail(&root->dldags, root); 1951 objlist_push_tail(&root->dagmembers, root); 1952 donelist_check(&donelist, root); 1953 1954 /* 1955 * Add dependencies of root object to DAG in breadth order 1956 * by exploiting the fact that each new object get added 1957 * to the tail of the dagmembers list. 1958 */ 1959 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1960 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1961 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1962 continue; 1963 objlist_push_tail(&needed->obj->dldags, root); 1964 objlist_push_tail(&root->dagmembers, needed->obj); 1965 } 1966 } 1967 root->dag_inited = true; 1968 } 1969 1970 static void 1971 init_marker(Obj_Entry *marker) 1972 { 1973 1974 bzero(marker, sizeof(*marker)); 1975 marker->marker = true; 1976 } 1977 1978 Obj_Entry * 1979 globallist_curr(const Obj_Entry *obj) 1980 { 1981 1982 for (;;) { 1983 if (obj == NULL) 1984 return (NULL); 1985 if (!obj->marker) 1986 return (__DECONST(Obj_Entry *, obj)); 1987 obj = TAILQ_PREV(obj, obj_entry_q, next); 1988 } 1989 } 1990 1991 Obj_Entry * 1992 globallist_next(const Obj_Entry *obj) 1993 { 1994 1995 for (;;) { 1996 obj = TAILQ_NEXT(obj, next); 1997 if (obj == NULL) 1998 return (NULL); 1999 if (!obj->marker) 2000 return (__DECONST(Obj_Entry *, obj)); 2001 } 2002 } 2003 2004 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2005 static void 2006 hold_object(Obj_Entry *obj) 2007 { 2008 2009 obj->holdcount++; 2010 } 2011 2012 static void 2013 unhold_object(Obj_Entry *obj) 2014 { 2015 2016 assert(obj->holdcount > 0); 2017 if (--obj->holdcount == 0 && obj->unholdfree) 2018 release_object(obj); 2019 } 2020 2021 static void 2022 process_z(Obj_Entry *root) 2023 { 2024 const Objlist_Entry *elm; 2025 Obj_Entry *obj; 2026 2027 /* 2028 * Walk over object DAG and process every dependent object 2029 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2030 * to grow their own DAG. 2031 * 2032 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2033 * symlook_global() to work. 2034 * 2035 * For DF_1_NODELETE, the DAG should have its reference upped. 2036 */ 2037 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2038 obj = elm->obj; 2039 if (obj == NULL) 2040 continue; 2041 if (obj->z_nodelete && !obj->ref_nodel) { 2042 dbg("obj %s -z nodelete", obj->path); 2043 init_dag(obj); 2044 ref_dag(obj); 2045 obj->ref_nodel = true; 2046 } 2047 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2048 dbg("obj %s -z global", obj->path); 2049 objlist_push_tail(&list_global, obj); 2050 init_dag(obj); 2051 } 2052 } 2053 } 2054 /* 2055 * Initialize the dynamic linker. The argument is the address at which 2056 * the dynamic linker has been mapped into memory. The primary task of 2057 * this function is to relocate the dynamic linker. 2058 */ 2059 static void 2060 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2061 { 2062 Obj_Entry objtmp; /* Temporary rtld object */ 2063 const Elf_Ehdr *ehdr; 2064 const Elf_Dyn *dyn_rpath; 2065 const Elf_Dyn *dyn_soname; 2066 const Elf_Dyn *dyn_runpath; 2067 2068 #ifdef RTLD_INIT_PAGESIZES_EARLY 2069 /* The page size is required by the dynamic memory allocator. */ 2070 init_pagesizes(aux_info); 2071 #endif 2072 2073 /* 2074 * Conjure up an Obj_Entry structure for the dynamic linker. 2075 * 2076 * The "path" member can't be initialized yet because string constants 2077 * cannot yet be accessed. Below we will set it correctly. 2078 */ 2079 memset(&objtmp, 0, sizeof(objtmp)); 2080 objtmp.path = NULL; 2081 objtmp.rtld = true; 2082 objtmp.mapbase = mapbase; 2083 #ifdef PIC 2084 objtmp.relocbase = mapbase; 2085 #endif 2086 2087 objtmp.dynamic = rtld_dynamic(&objtmp); 2088 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2089 assert(objtmp.needed == NULL); 2090 #if !defined(__mips__) 2091 /* MIPS has a bogus DT_TEXTREL. */ 2092 assert(!objtmp.textrel); 2093 #endif 2094 /* 2095 * Temporarily put the dynamic linker entry into the object list, so 2096 * that symbols can be found. 2097 */ 2098 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2099 2100 ehdr = (Elf_Ehdr *)mapbase; 2101 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2102 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2103 2104 /* Initialize the object list. */ 2105 TAILQ_INIT(&obj_list); 2106 2107 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2108 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2109 2110 #ifndef RTLD_INIT_PAGESIZES_EARLY 2111 /* The page size is required by the dynamic memory allocator. */ 2112 init_pagesizes(aux_info); 2113 #endif 2114 2115 if (aux_info[AT_OSRELDATE] != NULL) 2116 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2117 2118 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2119 2120 /* Replace the path with a dynamically allocated copy. */ 2121 obj_rtld.path = xstrdup(ld_path_rtld); 2122 2123 r_debug.r_brk = r_debug_state; 2124 r_debug.r_state = RT_CONSISTENT; 2125 } 2126 2127 /* 2128 * Retrieve the array of supported page sizes. The kernel provides the page 2129 * sizes in increasing order. 2130 */ 2131 static void 2132 init_pagesizes(Elf_Auxinfo **aux_info) 2133 { 2134 static size_t psa[MAXPAGESIZES]; 2135 int mib[2]; 2136 size_t len, size; 2137 2138 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2139 NULL) { 2140 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2141 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2142 } else { 2143 len = 2; 2144 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2145 size = sizeof(psa); 2146 else { 2147 /* As a fallback, retrieve the base page size. */ 2148 size = sizeof(psa[0]); 2149 if (aux_info[AT_PAGESZ] != NULL) { 2150 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2151 goto psa_filled; 2152 } else { 2153 mib[0] = CTL_HW; 2154 mib[1] = HW_PAGESIZE; 2155 len = 2; 2156 } 2157 } 2158 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2159 _rtld_error("sysctl for hw.pagesize(s) failed"); 2160 rtld_die(); 2161 } 2162 psa_filled: 2163 pagesizes = psa; 2164 } 2165 npagesizes = size / sizeof(pagesizes[0]); 2166 /* Discard any invalid entries at the end of the array. */ 2167 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2168 npagesizes--; 2169 } 2170 2171 /* 2172 * Add the init functions from a needed object list (and its recursive 2173 * needed objects) to "list". This is not used directly; it is a helper 2174 * function for initlist_add_objects(). The write lock must be held 2175 * when this function is called. 2176 */ 2177 static void 2178 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2179 { 2180 /* Recursively process the successor needed objects. */ 2181 if (needed->next != NULL) 2182 initlist_add_neededs(needed->next, list); 2183 2184 /* Process the current needed object. */ 2185 if (needed->obj != NULL) 2186 initlist_add_objects(needed->obj, needed->obj, list); 2187 } 2188 2189 /* 2190 * Scan all of the DAGs rooted in the range of objects from "obj" to 2191 * "tail" and add their init functions to "list". This recurses over 2192 * the DAGs and ensure the proper init ordering such that each object's 2193 * needed libraries are initialized before the object itself. At the 2194 * same time, this function adds the objects to the global finalization 2195 * list "list_fini" in the opposite order. The write lock must be 2196 * held when this function is called. 2197 */ 2198 static void 2199 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2200 { 2201 Obj_Entry *nobj; 2202 2203 if (obj->init_scanned || obj->init_done) 2204 return; 2205 obj->init_scanned = true; 2206 2207 /* Recursively process the successor objects. */ 2208 nobj = globallist_next(obj); 2209 if (nobj != NULL && obj != tail) 2210 initlist_add_objects(nobj, tail, list); 2211 2212 /* Recursively process the needed objects. */ 2213 if (obj->needed != NULL) 2214 initlist_add_neededs(obj->needed, list); 2215 if (obj->needed_filtees != NULL) 2216 initlist_add_neededs(obj->needed_filtees, list); 2217 if (obj->needed_aux_filtees != NULL) 2218 initlist_add_neededs(obj->needed_aux_filtees, list); 2219 2220 /* Add the object to the init list. */ 2221 objlist_push_tail(list, obj); 2222 2223 /* Add the object to the global fini list in the reverse order. */ 2224 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2225 && !obj->on_fini_list) { 2226 objlist_push_head(&list_fini, obj); 2227 obj->on_fini_list = true; 2228 } 2229 } 2230 2231 #ifndef FPTR_TARGET 2232 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2233 #endif 2234 2235 static void 2236 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2237 { 2238 Needed_Entry *needed, *needed1; 2239 2240 for (needed = n; needed != NULL; needed = needed->next) { 2241 if (needed->obj != NULL) { 2242 dlclose_locked(needed->obj, lockstate); 2243 needed->obj = NULL; 2244 } 2245 } 2246 for (needed = n; needed != NULL; needed = needed1) { 2247 needed1 = needed->next; 2248 free(needed); 2249 } 2250 } 2251 2252 static void 2253 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2254 { 2255 2256 free_needed_filtees(obj->needed_filtees, lockstate); 2257 obj->needed_filtees = NULL; 2258 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2259 obj->needed_aux_filtees = NULL; 2260 obj->filtees_loaded = false; 2261 } 2262 2263 static void 2264 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2265 RtldLockState *lockstate) 2266 { 2267 2268 for (; needed != NULL; needed = needed->next) { 2269 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2270 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2271 RTLD_LOCAL, lockstate); 2272 } 2273 } 2274 2275 static void 2276 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2277 { 2278 2279 lock_restart_for_upgrade(lockstate); 2280 if (!obj->filtees_loaded) { 2281 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2282 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2283 obj->filtees_loaded = true; 2284 } 2285 } 2286 2287 static int 2288 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2289 { 2290 Obj_Entry *obj1; 2291 2292 for (; needed != NULL; needed = needed->next) { 2293 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2294 flags & ~RTLD_LO_NOLOAD); 2295 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2296 return (-1); 2297 } 2298 return (0); 2299 } 2300 2301 /* 2302 * Given a shared object, traverse its list of needed objects, and load 2303 * each of them. Returns 0 on success. Generates an error message and 2304 * returns -1 on failure. 2305 */ 2306 static int 2307 load_needed_objects(Obj_Entry *first, int flags) 2308 { 2309 Obj_Entry *obj; 2310 2311 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2312 if (obj->marker) 2313 continue; 2314 if (process_needed(obj, obj->needed, flags) == -1) 2315 return (-1); 2316 } 2317 return (0); 2318 } 2319 2320 static int 2321 load_preload_objects(void) 2322 { 2323 char *p = ld_preload; 2324 Obj_Entry *obj; 2325 static const char delim[] = " \t:;"; 2326 2327 if (p == NULL) 2328 return 0; 2329 2330 p += strspn(p, delim); 2331 while (*p != '\0') { 2332 size_t len = strcspn(p, delim); 2333 char savech; 2334 2335 savech = p[len]; 2336 p[len] = '\0'; 2337 obj = load_object(p, -1, NULL, 0); 2338 if (obj == NULL) 2339 return -1; /* XXX - cleanup */ 2340 obj->z_interpose = true; 2341 p[len] = savech; 2342 p += len; 2343 p += strspn(p, delim); 2344 } 2345 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2346 return 0; 2347 } 2348 2349 static const char * 2350 printable_path(const char *path) 2351 { 2352 2353 return (path == NULL ? "<unknown>" : path); 2354 } 2355 2356 /* 2357 * Load a shared object into memory, if it is not already loaded. The 2358 * object may be specified by name or by user-supplied file descriptor 2359 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2360 * duplicate is. 2361 * 2362 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2363 * on failure. 2364 */ 2365 static Obj_Entry * 2366 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2367 { 2368 Obj_Entry *obj; 2369 int fd; 2370 struct stat sb; 2371 char *path; 2372 2373 fd = -1; 2374 if (name != NULL) { 2375 TAILQ_FOREACH(obj, &obj_list, next) { 2376 if (obj->marker || obj->doomed) 2377 continue; 2378 if (object_match_name(obj, name)) 2379 return (obj); 2380 } 2381 2382 path = find_library(name, refobj, &fd); 2383 if (path == NULL) 2384 return (NULL); 2385 } else 2386 path = NULL; 2387 2388 if (fd >= 0) { 2389 /* 2390 * search_library_pathfds() opens a fresh file descriptor for the 2391 * library, so there is no need to dup(). 2392 */ 2393 } else if (fd_u == -1) { 2394 /* 2395 * If we didn't find a match by pathname, or the name is not 2396 * supplied, open the file and check again by device and inode. 2397 * This avoids false mismatches caused by multiple links or ".." 2398 * in pathnames. 2399 * 2400 * To avoid a race, we open the file and use fstat() rather than 2401 * using stat(). 2402 */ 2403 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2404 _rtld_error("Cannot open \"%s\"", path); 2405 free(path); 2406 return (NULL); 2407 } 2408 } else { 2409 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2410 if (fd == -1) { 2411 _rtld_error("Cannot dup fd"); 2412 free(path); 2413 return (NULL); 2414 } 2415 } 2416 if (fstat(fd, &sb) == -1) { 2417 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2418 close(fd); 2419 free(path); 2420 return NULL; 2421 } 2422 TAILQ_FOREACH(obj, &obj_list, next) { 2423 if (obj->marker || obj->doomed) 2424 continue; 2425 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2426 break; 2427 } 2428 if (obj != NULL && name != NULL) { 2429 object_add_name(obj, name); 2430 free(path); 2431 close(fd); 2432 return obj; 2433 } 2434 if (flags & RTLD_LO_NOLOAD) { 2435 free(path); 2436 close(fd); 2437 return (NULL); 2438 } 2439 2440 /* First use of this object, so we must map it in */ 2441 obj = do_load_object(fd, name, path, &sb, flags); 2442 if (obj == NULL) 2443 free(path); 2444 close(fd); 2445 2446 return obj; 2447 } 2448 2449 static Obj_Entry * 2450 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2451 int flags) 2452 { 2453 Obj_Entry *obj; 2454 struct statfs fs; 2455 2456 /* 2457 * but first, make sure that environment variables haven't been 2458 * used to circumvent the noexec flag on a filesystem. 2459 */ 2460 if (dangerous_ld_env) { 2461 if (fstatfs(fd, &fs) != 0) { 2462 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2463 return NULL; 2464 } 2465 if (fs.f_flags & MNT_NOEXEC) { 2466 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2467 return NULL; 2468 } 2469 } 2470 dbg("loading \"%s\"", printable_path(path)); 2471 obj = map_object(fd, printable_path(path), sbp); 2472 if (obj == NULL) 2473 return NULL; 2474 2475 /* 2476 * If DT_SONAME is present in the object, digest_dynamic2 already 2477 * added it to the object names. 2478 */ 2479 if (name != NULL) 2480 object_add_name(obj, name); 2481 obj->path = path; 2482 digest_dynamic(obj, 0); 2483 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2484 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2485 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2486 RTLD_LO_DLOPEN) { 2487 dbg("refusing to load non-loadable \"%s\"", obj->path); 2488 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2489 munmap(obj->mapbase, obj->mapsize); 2490 obj_free(obj); 2491 return (NULL); 2492 } 2493 2494 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2495 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2496 obj_count++; 2497 obj_loads++; 2498 linkmap_add(obj); /* for GDB & dlinfo() */ 2499 max_stack_flags |= obj->stack_flags; 2500 2501 dbg(" %p .. %p: %s", obj->mapbase, 2502 obj->mapbase + obj->mapsize - 1, obj->path); 2503 if (obj->textrel) 2504 dbg(" WARNING: %s has impure text", obj->path); 2505 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2506 obj->path); 2507 2508 return obj; 2509 } 2510 2511 static Obj_Entry * 2512 obj_from_addr(const void *addr) 2513 { 2514 Obj_Entry *obj; 2515 2516 TAILQ_FOREACH(obj, &obj_list, next) { 2517 if (obj->marker) 2518 continue; 2519 if (addr < (void *) obj->mapbase) 2520 continue; 2521 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2522 return obj; 2523 } 2524 return NULL; 2525 } 2526 2527 static void 2528 preinit_main(void) 2529 { 2530 Elf_Addr *preinit_addr; 2531 int index; 2532 2533 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2534 if (preinit_addr == NULL) 2535 return; 2536 2537 for (index = 0; index < obj_main->preinit_array_num; index++) { 2538 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2539 dbg("calling preinit function for %s at %p", obj_main->path, 2540 (void *)preinit_addr[index]); 2541 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2542 0, 0, obj_main->path); 2543 call_init_pointer(obj_main, preinit_addr[index]); 2544 } 2545 } 2546 } 2547 2548 /* 2549 * Call the finalization functions for each of the objects in "list" 2550 * belonging to the DAG of "root" and referenced once. If NULL "root" 2551 * is specified, every finalization function will be called regardless 2552 * of the reference count and the list elements won't be freed. All of 2553 * the objects are expected to have non-NULL fini functions. 2554 */ 2555 static void 2556 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2557 { 2558 Objlist_Entry *elm; 2559 char *saved_msg; 2560 Elf_Addr *fini_addr; 2561 int index; 2562 2563 assert(root == NULL || root->refcount == 1); 2564 2565 if (root != NULL) 2566 root->doomed = true; 2567 2568 /* 2569 * Preserve the current error message since a fini function might 2570 * call into the dynamic linker and overwrite it. 2571 */ 2572 saved_msg = errmsg_save(); 2573 do { 2574 STAILQ_FOREACH(elm, list, link) { 2575 if (root != NULL && (elm->obj->refcount != 1 || 2576 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2577 continue; 2578 /* Remove object from fini list to prevent recursive invocation. */ 2579 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2580 /* Ensure that new references cannot be acquired. */ 2581 elm->obj->doomed = true; 2582 2583 hold_object(elm->obj); 2584 lock_release(rtld_bind_lock, lockstate); 2585 /* 2586 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2587 * When this happens, DT_FINI_ARRAY is processed first. 2588 */ 2589 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2590 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2591 for (index = elm->obj->fini_array_num - 1; index >= 0; 2592 index--) { 2593 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2594 dbg("calling fini function for %s at %p", 2595 elm->obj->path, (void *)fini_addr[index]); 2596 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2597 (void *)fini_addr[index], 0, 0, elm->obj->path); 2598 call_initfini_pointer(elm->obj, fini_addr[index]); 2599 } 2600 } 2601 } 2602 if (elm->obj->fini != (Elf_Addr)NULL) { 2603 dbg("calling fini function for %s at %p", elm->obj->path, 2604 (void *)elm->obj->fini); 2605 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2606 0, 0, elm->obj->path); 2607 call_initfini_pointer(elm->obj, elm->obj->fini); 2608 } 2609 wlock_acquire(rtld_bind_lock, lockstate); 2610 unhold_object(elm->obj); 2611 /* No need to free anything if process is going down. */ 2612 if (root != NULL) 2613 free(elm); 2614 /* 2615 * We must restart the list traversal after every fini call 2616 * because a dlclose() call from the fini function or from 2617 * another thread might have modified the reference counts. 2618 */ 2619 break; 2620 } 2621 } while (elm != NULL); 2622 errmsg_restore(saved_msg); 2623 } 2624 2625 /* 2626 * Call the initialization functions for each of the objects in 2627 * "list". All of the objects are expected to have non-NULL init 2628 * functions. 2629 */ 2630 static void 2631 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2632 { 2633 Objlist_Entry *elm; 2634 Obj_Entry *obj; 2635 char *saved_msg; 2636 Elf_Addr *init_addr; 2637 int index; 2638 2639 /* 2640 * Clean init_scanned flag so that objects can be rechecked and 2641 * possibly initialized earlier if any of vectors called below 2642 * cause the change by using dlopen. 2643 */ 2644 TAILQ_FOREACH(obj, &obj_list, next) { 2645 if (obj->marker) 2646 continue; 2647 obj->init_scanned = false; 2648 } 2649 2650 /* 2651 * Preserve the current error message since an init function might 2652 * call into the dynamic linker and overwrite it. 2653 */ 2654 saved_msg = errmsg_save(); 2655 STAILQ_FOREACH(elm, list, link) { 2656 if (elm->obj->init_done) /* Initialized early. */ 2657 continue; 2658 /* 2659 * Race: other thread might try to use this object before current 2660 * one completes the initialization. Not much can be done here 2661 * without better locking. 2662 */ 2663 elm->obj->init_done = true; 2664 hold_object(elm->obj); 2665 lock_release(rtld_bind_lock, lockstate); 2666 2667 /* 2668 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2669 * When this happens, DT_INIT is processed first. 2670 */ 2671 if (elm->obj->init != (Elf_Addr)NULL) { 2672 dbg("calling init function for %s at %p", elm->obj->path, 2673 (void *)elm->obj->init); 2674 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2675 0, 0, elm->obj->path); 2676 call_initfini_pointer(elm->obj, elm->obj->init); 2677 } 2678 init_addr = (Elf_Addr *)elm->obj->init_array; 2679 if (init_addr != NULL) { 2680 for (index = 0; index < elm->obj->init_array_num; index++) { 2681 if (init_addr[index] != 0 && init_addr[index] != 1) { 2682 dbg("calling init function for %s at %p", elm->obj->path, 2683 (void *)init_addr[index]); 2684 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2685 (void *)init_addr[index], 0, 0, elm->obj->path); 2686 call_init_pointer(elm->obj, init_addr[index]); 2687 } 2688 } 2689 } 2690 wlock_acquire(rtld_bind_lock, lockstate); 2691 unhold_object(elm->obj); 2692 } 2693 errmsg_restore(saved_msg); 2694 } 2695 2696 static void 2697 objlist_clear(Objlist *list) 2698 { 2699 Objlist_Entry *elm; 2700 2701 while (!STAILQ_EMPTY(list)) { 2702 elm = STAILQ_FIRST(list); 2703 STAILQ_REMOVE_HEAD(list, link); 2704 free(elm); 2705 } 2706 } 2707 2708 static Objlist_Entry * 2709 objlist_find(Objlist *list, const Obj_Entry *obj) 2710 { 2711 Objlist_Entry *elm; 2712 2713 STAILQ_FOREACH(elm, list, link) 2714 if (elm->obj == obj) 2715 return elm; 2716 return NULL; 2717 } 2718 2719 static void 2720 objlist_init(Objlist *list) 2721 { 2722 STAILQ_INIT(list); 2723 } 2724 2725 static void 2726 objlist_push_head(Objlist *list, Obj_Entry *obj) 2727 { 2728 Objlist_Entry *elm; 2729 2730 elm = NEW(Objlist_Entry); 2731 elm->obj = obj; 2732 STAILQ_INSERT_HEAD(list, elm, link); 2733 } 2734 2735 static void 2736 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2737 { 2738 Objlist_Entry *elm; 2739 2740 elm = NEW(Objlist_Entry); 2741 elm->obj = obj; 2742 STAILQ_INSERT_TAIL(list, elm, link); 2743 } 2744 2745 static void 2746 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2747 { 2748 Objlist_Entry *elm, *listelm; 2749 2750 STAILQ_FOREACH(listelm, list, link) { 2751 if (listelm->obj == listobj) 2752 break; 2753 } 2754 elm = NEW(Objlist_Entry); 2755 elm->obj = obj; 2756 if (listelm != NULL) 2757 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2758 else 2759 STAILQ_INSERT_TAIL(list, elm, link); 2760 } 2761 2762 static void 2763 objlist_remove(Objlist *list, Obj_Entry *obj) 2764 { 2765 Objlist_Entry *elm; 2766 2767 if ((elm = objlist_find(list, obj)) != NULL) { 2768 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2769 free(elm); 2770 } 2771 } 2772 2773 /* 2774 * Relocate dag rooted in the specified object. 2775 * Returns 0 on success, or -1 on failure. 2776 */ 2777 2778 static int 2779 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2780 int flags, RtldLockState *lockstate) 2781 { 2782 Objlist_Entry *elm; 2783 int error; 2784 2785 error = 0; 2786 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2787 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2788 lockstate); 2789 if (error == -1) 2790 break; 2791 } 2792 return (error); 2793 } 2794 2795 /* 2796 * Prepare for, or clean after, relocating an object marked with 2797 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2798 * segments are remapped read-write. After relocations are done, the 2799 * segment's permissions are returned back to the modes specified in 2800 * the phdrs. If any relocation happened, or always for wired 2801 * program, COW is triggered. 2802 */ 2803 static int 2804 reloc_textrel_prot(Obj_Entry *obj, bool before) 2805 { 2806 const Elf_Phdr *ph; 2807 void *base; 2808 size_t l, sz; 2809 int prot; 2810 2811 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2812 l--, ph++) { 2813 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2814 continue; 2815 base = obj->relocbase + trunc_page(ph->p_vaddr); 2816 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2817 trunc_page(ph->p_vaddr); 2818 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2819 if (mprotect(base, sz, prot) == -1) { 2820 _rtld_error("%s: Cannot write-%sable text segment: %s", 2821 obj->path, before ? "en" : "dis", 2822 rtld_strerror(errno)); 2823 return (-1); 2824 } 2825 } 2826 return (0); 2827 } 2828 2829 /* 2830 * Relocate single object. 2831 * Returns 0 on success, or -1 on failure. 2832 */ 2833 static int 2834 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2835 int flags, RtldLockState *lockstate) 2836 { 2837 2838 if (obj->relocated) 2839 return (0); 2840 obj->relocated = true; 2841 if (obj != rtldobj) 2842 dbg("relocating \"%s\"", obj->path); 2843 2844 if (obj->symtab == NULL || obj->strtab == NULL || 2845 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2846 _rtld_error("%s: Shared object has no run-time symbol table", 2847 obj->path); 2848 return (-1); 2849 } 2850 2851 /* There are relocations to the write-protected text segment. */ 2852 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2853 return (-1); 2854 2855 /* Process the non-PLT non-IFUNC relocations. */ 2856 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2857 return (-1); 2858 2859 /* Re-protected the text segment. */ 2860 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2861 return (-1); 2862 2863 /* Set the special PLT or GOT entries. */ 2864 init_pltgot(obj); 2865 2866 /* Process the PLT relocations. */ 2867 if (reloc_plt(obj, flags, lockstate) == -1) 2868 return (-1); 2869 /* Relocate the jump slots if we are doing immediate binding. */ 2870 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2871 lockstate) == -1) 2872 return (-1); 2873 2874 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2875 return (-1); 2876 2877 /* 2878 * Set up the magic number and version in the Obj_Entry. These 2879 * were checked in the crt1.o from the original ElfKit, so we 2880 * set them for backward compatibility. 2881 */ 2882 obj->magic = RTLD_MAGIC; 2883 obj->version = RTLD_VERSION; 2884 2885 return (0); 2886 } 2887 2888 /* 2889 * Relocate newly-loaded shared objects. The argument is a pointer to 2890 * the Obj_Entry for the first such object. All objects from the first 2891 * to the end of the list of objects are relocated. Returns 0 on success, 2892 * or -1 on failure. 2893 */ 2894 static int 2895 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2896 int flags, RtldLockState *lockstate) 2897 { 2898 Obj_Entry *obj; 2899 int error; 2900 2901 for (error = 0, obj = first; obj != NULL; 2902 obj = TAILQ_NEXT(obj, next)) { 2903 if (obj->marker) 2904 continue; 2905 error = relocate_object(obj, bind_now, rtldobj, flags, 2906 lockstate); 2907 if (error == -1) 2908 break; 2909 } 2910 return (error); 2911 } 2912 2913 /* 2914 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2915 * referencing STT_GNU_IFUNC symbols is postponed till the other 2916 * relocations are done. The indirect functions specified as 2917 * ifunc are allowed to call other symbols, so we need to have 2918 * objects relocated before asking for resolution from indirects. 2919 * 2920 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2921 * instead of the usual lazy handling of PLT slots. It is 2922 * consistent with how GNU does it. 2923 */ 2924 static int 2925 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2926 RtldLockState *lockstate) 2927 { 2928 2929 if (obj->ifuncs_resolved) 2930 return (0); 2931 obj->ifuncs_resolved = true; 2932 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2933 return (-1); 2934 if ((obj->bind_now || bind_now) && obj->gnu_ifunc) { 2935 if (obj_disable_relro(obj) || 2936 reloc_gnu_ifunc(obj, flags, lockstate) == -1 || 2937 obj_enforce_relro(obj)) 2938 return (-1); 2939 } 2940 return (0); 2941 } 2942 2943 static int 2944 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2945 RtldLockState *lockstate) 2946 { 2947 Objlist_Entry *elm; 2948 Obj_Entry *obj; 2949 2950 STAILQ_FOREACH(elm, list, link) { 2951 obj = elm->obj; 2952 if (obj->marker) 2953 continue; 2954 if (resolve_object_ifunc(obj, bind_now, flags, 2955 lockstate) == -1) 2956 return (-1); 2957 } 2958 return (0); 2959 } 2960 2961 /* 2962 * Cleanup procedure. It will be called (by the atexit mechanism) just 2963 * before the process exits. 2964 */ 2965 static void 2966 rtld_exit(void) 2967 { 2968 RtldLockState lockstate; 2969 2970 wlock_acquire(rtld_bind_lock, &lockstate); 2971 dbg("rtld_exit()"); 2972 objlist_call_fini(&list_fini, NULL, &lockstate); 2973 /* No need to remove the items from the list, since we are exiting. */ 2974 if (!libmap_disable) 2975 lm_fini(); 2976 lock_release(rtld_bind_lock, &lockstate); 2977 } 2978 2979 /* 2980 * Iterate over a search path, translate each element, and invoke the 2981 * callback on the result. 2982 */ 2983 static void * 2984 path_enumerate(const char *path, path_enum_proc callback, 2985 const char *refobj_path, void *arg) 2986 { 2987 const char *trans; 2988 if (path == NULL) 2989 return (NULL); 2990 2991 path += strspn(path, ":;"); 2992 while (*path != '\0') { 2993 size_t len; 2994 char *res; 2995 2996 len = strcspn(path, ":;"); 2997 trans = lm_findn(refobj_path, path, len); 2998 if (trans) 2999 res = callback(trans, strlen(trans), arg); 3000 else 3001 res = callback(path, len, arg); 3002 3003 if (res != NULL) 3004 return (res); 3005 3006 path += len; 3007 path += strspn(path, ":;"); 3008 } 3009 3010 return (NULL); 3011 } 3012 3013 struct try_library_args { 3014 const char *name; 3015 size_t namelen; 3016 char *buffer; 3017 size_t buflen; 3018 int fd; 3019 }; 3020 3021 static void * 3022 try_library_path(const char *dir, size_t dirlen, void *param) 3023 { 3024 struct try_library_args *arg; 3025 int fd; 3026 3027 arg = param; 3028 if (*dir == '/' || trust) { 3029 char *pathname; 3030 3031 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3032 return (NULL); 3033 3034 pathname = arg->buffer; 3035 strncpy(pathname, dir, dirlen); 3036 pathname[dirlen] = '/'; 3037 strcpy(pathname + dirlen + 1, arg->name); 3038 3039 dbg(" Trying \"%s\"", pathname); 3040 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3041 if (fd >= 0) { 3042 dbg(" Opened \"%s\", fd %d", pathname, fd); 3043 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3044 strcpy(pathname, arg->buffer); 3045 arg->fd = fd; 3046 return (pathname); 3047 } else { 3048 dbg(" Failed to open \"%s\": %s", 3049 pathname, rtld_strerror(errno)); 3050 } 3051 } 3052 return (NULL); 3053 } 3054 3055 static char * 3056 search_library_path(const char *name, const char *path, 3057 const char *refobj_path, int *fdp) 3058 { 3059 char *p; 3060 struct try_library_args arg; 3061 3062 if (path == NULL) 3063 return NULL; 3064 3065 arg.name = name; 3066 arg.namelen = strlen(name); 3067 arg.buffer = xmalloc(PATH_MAX); 3068 arg.buflen = PATH_MAX; 3069 arg.fd = -1; 3070 3071 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3072 *fdp = arg.fd; 3073 3074 free(arg.buffer); 3075 3076 return (p); 3077 } 3078 3079 3080 /* 3081 * Finds the library with the given name using the directory descriptors 3082 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3083 * 3084 * Returns a freshly-opened close-on-exec file descriptor for the library, 3085 * or -1 if the library cannot be found. 3086 */ 3087 static char * 3088 search_library_pathfds(const char *name, const char *path, int *fdp) 3089 { 3090 char *envcopy, *fdstr, *found, *last_token; 3091 size_t len; 3092 int dirfd, fd; 3093 3094 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3095 3096 /* Don't load from user-specified libdirs into setuid binaries. */ 3097 if (!trust) 3098 return (NULL); 3099 3100 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3101 if (path == NULL) 3102 return (NULL); 3103 3104 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3105 if (name[0] == '/') { 3106 dbg("Absolute path (%s) passed to %s", name, __func__); 3107 return (NULL); 3108 } 3109 3110 /* 3111 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3112 * copy of the path, as strtok_r rewrites separator tokens 3113 * with '\0'. 3114 */ 3115 found = NULL; 3116 envcopy = xstrdup(path); 3117 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3118 fdstr = strtok_r(NULL, ":", &last_token)) { 3119 dirfd = parse_integer(fdstr); 3120 if (dirfd < 0) { 3121 _rtld_error("failed to parse directory FD: '%s'", 3122 fdstr); 3123 break; 3124 } 3125 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3126 if (fd >= 0) { 3127 *fdp = fd; 3128 len = strlen(fdstr) + strlen(name) + 3; 3129 found = xmalloc(len); 3130 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3131 _rtld_error("error generating '%d/%s'", 3132 dirfd, name); 3133 rtld_die(); 3134 } 3135 dbg("open('%s') => %d", found, fd); 3136 break; 3137 } 3138 } 3139 free(envcopy); 3140 3141 return (found); 3142 } 3143 3144 3145 int 3146 dlclose(void *handle) 3147 { 3148 RtldLockState lockstate; 3149 int error; 3150 3151 wlock_acquire(rtld_bind_lock, &lockstate); 3152 error = dlclose_locked(handle, &lockstate); 3153 lock_release(rtld_bind_lock, &lockstate); 3154 return (error); 3155 } 3156 3157 static int 3158 dlclose_locked(void *handle, RtldLockState *lockstate) 3159 { 3160 Obj_Entry *root; 3161 3162 root = dlcheck(handle); 3163 if (root == NULL) 3164 return -1; 3165 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3166 root->path); 3167 3168 /* Unreference the object and its dependencies. */ 3169 root->dl_refcount--; 3170 3171 if (root->refcount == 1) { 3172 /* 3173 * The object will be no longer referenced, so we must unload it. 3174 * First, call the fini functions. 3175 */ 3176 objlist_call_fini(&list_fini, root, lockstate); 3177 3178 unref_dag(root); 3179 3180 /* Finish cleaning up the newly-unreferenced objects. */ 3181 GDB_STATE(RT_DELETE,&root->linkmap); 3182 unload_object(root, lockstate); 3183 GDB_STATE(RT_CONSISTENT,NULL); 3184 } else 3185 unref_dag(root); 3186 3187 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3188 return 0; 3189 } 3190 3191 char * 3192 dlerror(void) 3193 { 3194 char *msg = error_message; 3195 error_message = NULL; 3196 return msg; 3197 } 3198 3199 /* 3200 * This function is deprecated and has no effect. 3201 */ 3202 void 3203 dllockinit(void *context, 3204 void *(*lock_create)(void *context), 3205 void (*rlock_acquire)(void *lock), 3206 void (*wlock_acquire)(void *lock), 3207 void (*lock_release)(void *lock), 3208 void (*lock_destroy)(void *lock), 3209 void (*context_destroy)(void *context)) 3210 { 3211 static void *cur_context; 3212 static void (*cur_context_destroy)(void *); 3213 3214 /* Just destroy the context from the previous call, if necessary. */ 3215 if (cur_context_destroy != NULL) 3216 cur_context_destroy(cur_context); 3217 cur_context = context; 3218 cur_context_destroy = context_destroy; 3219 } 3220 3221 void * 3222 dlopen(const char *name, int mode) 3223 { 3224 3225 return (rtld_dlopen(name, -1, mode)); 3226 } 3227 3228 void * 3229 fdlopen(int fd, int mode) 3230 { 3231 3232 return (rtld_dlopen(NULL, fd, mode)); 3233 } 3234 3235 static void * 3236 rtld_dlopen(const char *name, int fd, int mode) 3237 { 3238 RtldLockState lockstate; 3239 int lo_flags; 3240 3241 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3242 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3243 if (ld_tracing != NULL) { 3244 rlock_acquire(rtld_bind_lock, &lockstate); 3245 if (sigsetjmp(lockstate.env, 0) != 0) 3246 lock_upgrade(rtld_bind_lock, &lockstate); 3247 environ = (char **)*get_program_var_addr("environ", &lockstate); 3248 lock_release(rtld_bind_lock, &lockstate); 3249 } 3250 lo_flags = RTLD_LO_DLOPEN; 3251 if (mode & RTLD_NODELETE) 3252 lo_flags |= RTLD_LO_NODELETE; 3253 if (mode & RTLD_NOLOAD) 3254 lo_flags |= RTLD_LO_NOLOAD; 3255 if (ld_tracing != NULL) 3256 lo_flags |= RTLD_LO_TRACE; 3257 3258 return (dlopen_object(name, fd, obj_main, lo_flags, 3259 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3260 } 3261 3262 static void 3263 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3264 { 3265 3266 obj->dl_refcount--; 3267 unref_dag(obj); 3268 if (obj->refcount == 0) 3269 unload_object(obj, lockstate); 3270 } 3271 3272 static Obj_Entry * 3273 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3274 int mode, RtldLockState *lockstate) 3275 { 3276 Obj_Entry *old_obj_tail; 3277 Obj_Entry *obj; 3278 Objlist initlist; 3279 RtldLockState mlockstate; 3280 int result; 3281 3282 objlist_init(&initlist); 3283 3284 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3285 wlock_acquire(rtld_bind_lock, &mlockstate); 3286 lockstate = &mlockstate; 3287 } 3288 GDB_STATE(RT_ADD,NULL); 3289 3290 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3291 obj = NULL; 3292 if (name == NULL && fd == -1) { 3293 obj = obj_main; 3294 obj->refcount++; 3295 } else { 3296 obj = load_object(name, fd, refobj, lo_flags); 3297 } 3298 3299 if (obj) { 3300 obj->dl_refcount++; 3301 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3302 objlist_push_tail(&list_global, obj); 3303 if (globallist_next(old_obj_tail) != NULL) { 3304 /* We loaded something new. */ 3305 assert(globallist_next(old_obj_tail) == obj); 3306 result = load_needed_objects(obj, 3307 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3308 init_dag(obj); 3309 ref_dag(obj); 3310 if (result != -1) 3311 result = rtld_verify_versions(&obj->dagmembers); 3312 if (result != -1 && ld_tracing) 3313 goto trace; 3314 if (result == -1 || relocate_object_dag(obj, 3315 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3316 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3317 lockstate) == -1) { 3318 dlopen_cleanup(obj, lockstate); 3319 obj = NULL; 3320 } else if (lo_flags & RTLD_LO_EARLY) { 3321 /* 3322 * Do not call the init functions for early loaded 3323 * filtees. The image is still not initialized enough 3324 * for them to work. 3325 * 3326 * Our object is found by the global object list and 3327 * will be ordered among all init calls done right 3328 * before transferring control to main. 3329 */ 3330 } else { 3331 /* Make list of init functions to call. */ 3332 initlist_add_objects(obj, obj, &initlist); 3333 } 3334 /* 3335 * Process all no_delete or global objects here, given 3336 * them own DAGs to prevent their dependencies from being 3337 * unloaded. This has to be done after we have loaded all 3338 * of the dependencies, so that we do not miss any. 3339 */ 3340 if (obj != NULL) 3341 process_z(obj); 3342 } else { 3343 /* 3344 * Bump the reference counts for objects on this DAG. If 3345 * this is the first dlopen() call for the object that was 3346 * already loaded as a dependency, initialize the dag 3347 * starting at it. 3348 */ 3349 init_dag(obj); 3350 ref_dag(obj); 3351 3352 if ((lo_flags & RTLD_LO_TRACE) != 0) 3353 goto trace; 3354 } 3355 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3356 obj->z_nodelete) && !obj->ref_nodel) { 3357 dbg("obj %s nodelete", obj->path); 3358 ref_dag(obj); 3359 obj->z_nodelete = obj->ref_nodel = true; 3360 } 3361 } 3362 3363 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3364 name); 3365 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3366 3367 if (!(lo_flags & RTLD_LO_EARLY)) { 3368 map_stacks_exec(lockstate); 3369 } 3370 3371 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3372 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3373 lockstate) == -1) { 3374 objlist_clear(&initlist); 3375 dlopen_cleanup(obj, lockstate); 3376 if (lockstate == &mlockstate) 3377 lock_release(rtld_bind_lock, lockstate); 3378 return (NULL); 3379 } 3380 3381 if (!(lo_flags & RTLD_LO_EARLY)) { 3382 /* Call the init functions. */ 3383 objlist_call_init(&initlist, lockstate); 3384 } 3385 objlist_clear(&initlist); 3386 if (lockstate == &mlockstate) 3387 lock_release(rtld_bind_lock, lockstate); 3388 return obj; 3389 trace: 3390 trace_loaded_objects(obj); 3391 if (lockstate == &mlockstate) 3392 lock_release(rtld_bind_lock, lockstate); 3393 exit(0); 3394 } 3395 3396 static void * 3397 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3398 int flags) 3399 { 3400 DoneList donelist; 3401 const Obj_Entry *obj, *defobj; 3402 const Elf_Sym *def; 3403 SymLook req; 3404 RtldLockState lockstate; 3405 tls_index ti; 3406 void *sym; 3407 int res; 3408 3409 def = NULL; 3410 defobj = NULL; 3411 symlook_init(&req, name); 3412 req.ventry = ve; 3413 req.flags = flags | SYMLOOK_IN_PLT; 3414 req.lockstate = &lockstate; 3415 3416 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3417 rlock_acquire(rtld_bind_lock, &lockstate); 3418 if (sigsetjmp(lockstate.env, 0) != 0) 3419 lock_upgrade(rtld_bind_lock, &lockstate); 3420 if (handle == NULL || handle == RTLD_NEXT || 3421 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3422 3423 if ((obj = obj_from_addr(retaddr)) == NULL) { 3424 _rtld_error("Cannot determine caller's shared object"); 3425 lock_release(rtld_bind_lock, &lockstate); 3426 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3427 return NULL; 3428 } 3429 if (handle == NULL) { /* Just the caller's shared object. */ 3430 res = symlook_obj(&req, obj); 3431 if (res == 0) { 3432 def = req.sym_out; 3433 defobj = req.defobj_out; 3434 } 3435 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3436 handle == RTLD_SELF) { /* ... caller included */ 3437 if (handle == RTLD_NEXT) 3438 obj = globallist_next(obj); 3439 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3440 if (obj->marker) 3441 continue; 3442 res = symlook_obj(&req, obj); 3443 if (res == 0) { 3444 if (def == NULL || 3445 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3446 def = req.sym_out; 3447 defobj = req.defobj_out; 3448 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3449 break; 3450 } 3451 } 3452 } 3453 /* 3454 * Search the dynamic linker itself, and possibly resolve the 3455 * symbol from there. This is how the application links to 3456 * dynamic linker services such as dlopen. 3457 */ 3458 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3459 res = symlook_obj(&req, &obj_rtld); 3460 if (res == 0) { 3461 def = req.sym_out; 3462 defobj = req.defobj_out; 3463 } 3464 } 3465 } else { 3466 assert(handle == RTLD_DEFAULT); 3467 res = symlook_default(&req, obj); 3468 if (res == 0) { 3469 defobj = req.defobj_out; 3470 def = req.sym_out; 3471 } 3472 } 3473 } else { 3474 if ((obj = dlcheck(handle)) == NULL) { 3475 lock_release(rtld_bind_lock, &lockstate); 3476 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3477 return NULL; 3478 } 3479 3480 donelist_init(&donelist); 3481 if (obj->mainprog) { 3482 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3483 res = symlook_global(&req, &donelist); 3484 if (res == 0) { 3485 def = req.sym_out; 3486 defobj = req.defobj_out; 3487 } 3488 /* 3489 * Search the dynamic linker itself, and possibly resolve the 3490 * symbol from there. This is how the application links to 3491 * dynamic linker services such as dlopen. 3492 */ 3493 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3494 res = symlook_obj(&req, &obj_rtld); 3495 if (res == 0) { 3496 def = req.sym_out; 3497 defobj = req.defobj_out; 3498 } 3499 } 3500 } 3501 else { 3502 /* Search the whole DAG rooted at the given object. */ 3503 res = symlook_list(&req, &obj->dagmembers, &donelist); 3504 if (res == 0) { 3505 def = req.sym_out; 3506 defobj = req.defobj_out; 3507 } 3508 } 3509 } 3510 3511 if (def != NULL) { 3512 lock_release(rtld_bind_lock, &lockstate); 3513 3514 /* 3515 * The value required by the caller is derived from the value 3516 * of the symbol. this is simply the relocated value of the 3517 * symbol. 3518 */ 3519 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3520 sym = make_function_pointer(def, defobj); 3521 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3522 sym = rtld_resolve_ifunc(defobj, def); 3523 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3524 ti.ti_module = defobj->tlsindex; 3525 ti.ti_offset = def->st_value; 3526 sym = __tls_get_addr(&ti); 3527 } else 3528 sym = defobj->relocbase + def->st_value; 3529 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3530 return (sym); 3531 } 3532 3533 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3534 ve != NULL ? ve->name : ""); 3535 lock_release(rtld_bind_lock, &lockstate); 3536 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3537 return NULL; 3538 } 3539 3540 void * 3541 dlsym(void *handle, const char *name) 3542 { 3543 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3544 SYMLOOK_DLSYM); 3545 } 3546 3547 dlfunc_t 3548 dlfunc(void *handle, const char *name) 3549 { 3550 union { 3551 void *d; 3552 dlfunc_t f; 3553 } rv; 3554 3555 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3556 SYMLOOK_DLSYM); 3557 return (rv.f); 3558 } 3559 3560 void * 3561 dlvsym(void *handle, const char *name, const char *version) 3562 { 3563 Ver_Entry ventry; 3564 3565 ventry.name = version; 3566 ventry.file = NULL; 3567 ventry.hash = elf_hash(version); 3568 ventry.flags= 0; 3569 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3570 SYMLOOK_DLSYM); 3571 } 3572 3573 int 3574 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3575 { 3576 const Obj_Entry *obj; 3577 RtldLockState lockstate; 3578 3579 rlock_acquire(rtld_bind_lock, &lockstate); 3580 obj = obj_from_addr(addr); 3581 if (obj == NULL) { 3582 _rtld_error("No shared object contains address"); 3583 lock_release(rtld_bind_lock, &lockstate); 3584 return (0); 3585 } 3586 rtld_fill_dl_phdr_info(obj, phdr_info); 3587 lock_release(rtld_bind_lock, &lockstate); 3588 return (1); 3589 } 3590 3591 int 3592 dladdr(const void *addr, Dl_info *info) 3593 { 3594 const Obj_Entry *obj; 3595 const Elf_Sym *def; 3596 void *symbol_addr; 3597 unsigned long symoffset; 3598 RtldLockState lockstate; 3599 3600 rlock_acquire(rtld_bind_lock, &lockstate); 3601 obj = obj_from_addr(addr); 3602 if (obj == NULL) { 3603 _rtld_error("No shared object contains address"); 3604 lock_release(rtld_bind_lock, &lockstate); 3605 return 0; 3606 } 3607 info->dli_fname = obj->path; 3608 info->dli_fbase = obj->mapbase; 3609 info->dli_saddr = (void *)0; 3610 info->dli_sname = NULL; 3611 3612 /* 3613 * Walk the symbol list looking for the symbol whose address is 3614 * closest to the address sent in. 3615 */ 3616 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3617 def = obj->symtab + symoffset; 3618 3619 /* 3620 * For skip the symbol if st_shndx is either SHN_UNDEF or 3621 * SHN_COMMON. 3622 */ 3623 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3624 continue; 3625 3626 /* 3627 * If the symbol is greater than the specified address, or if it 3628 * is further away from addr than the current nearest symbol, 3629 * then reject it. 3630 */ 3631 symbol_addr = obj->relocbase + def->st_value; 3632 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3633 continue; 3634 3635 /* Update our idea of the nearest symbol. */ 3636 info->dli_sname = obj->strtab + def->st_name; 3637 info->dli_saddr = symbol_addr; 3638 3639 /* Exact match? */ 3640 if (info->dli_saddr == addr) 3641 break; 3642 } 3643 lock_release(rtld_bind_lock, &lockstate); 3644 return 1; 3645 } 3646 3647 int 3648 dlinfo(void *handle, int request, void *p) 3649 { 3650 const Obj_Entry *obj; 3651 RtldLockState lockstate; 3652 int error; 3653 3654 rlock_acquire(rtld_bind_lock, &lockstate); 3655 3656 if (handle == NULL || handle == RTLD_SELF) { 3657 void *retaddr; 3658 3659 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3660 if ((obj = obj_from_addr(retaddr)) == NULL) 3661 _rtld_error("Cannot determine caller's shared object"); 3662 } else 3663 obj = dlcheck(handle); 3664 3665 if (obj == NULL) { 3666 lock_release(rtld_bind_lock, &lockstate); 3667 return (-1); 3668 } 3669 3670 error = 0; 3671 switch (request) { 3672 case RTLD_DI_LINKMAP: 3673 *((struct link_map const **)p) = &obj->linkmap; 3674 break; 3675 case RTLD_DI_ORIGIN: 3676 error = rtld_dirname(obj->path, p); 3677 break; 3678 3679 case RTLD_DI_SERINFOSIZE: 3680 case RTLD_DI_SERINFO: 3681 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3682 break; 3683 3684 default: 3685 _rtld_error("Invalid request %d passed to dlinfo()", request); 3686 error = -1; 3687 } 3688 3689 lock_release(rtld_bind_lock, &lockstate); 3690 3691 return (error); 3692 } 3693 3694 static void 3695 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3696 { 3697 3698 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3699 phdr_info->dlpi_name = obj->path; 3700 phdr_info->dlpi_phdr = obj->phdr; 3701 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3702 phdr_info->dlpi_tls_modid = obj->tlsindex; 3703 phdr_info->dlpi_tls_data = obj->tlsinit; 3704 phdr_info->dlpi_adds = obj_loads; 3705 phdr_info->dlpi_subs = obj_loads - obj_count; 3706 } 3707 3708 int 3709 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3710 { 3711 struct dl_phdr_info phdr_info; 3712 Obj_Entry *obj, marker; 3713 RtldLockState bind_lockstate, phdr_lockstate; 3714 int error; 3715 3716 init_marker(&marker); 3717 error = 0; 3718 3719 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3720 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3721 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3722 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3723 rtld_fill_dl_phdr_info(obj, &phdr_info); 3724 hold_object(obj); 3725 lock_release(rtld_bind_lock, &bind_lockstate); 3726 3727 error = callback(&phdr_info, sizeof phdr_info, param); 3728 3729 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3730 unhold_object(obj); 3731 obj = globallist_next(&marker); 3732 TAILQ_REMOVE(&obj_list, &marker, next); 3733 if (error != 0) { 3734 lock_release(rtld_bind_lock, &bind_lockstate); 3735 lock_release(rtld_phdr_lock, &phdr_lockstate); 3736 return (error); 3737 } 3738 } 3739 3740 if (error == 0) { 3741 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3742 lock_release(rtld_bind_lock, &bind_lockstate); 3743 error = callback(&phdr_info, sizeof(phdr_info), param); 3744 } 3745 lock_release(rtld_phdr_lock, &phdr_lockstate); 3746 return (error); 3747 } 3748 3749 static void * 3750 fill_search_info(const char *dir, size_t dirlen, void *param) 3751 { 3752 struct fill_search_info_args *arg; 3753 3754 arg = param; 3755 3756 if (arg->request == RTLD_DI_SERINFOSIZE) { 3757 arg->serinfo->dls_cnt ++; 3758 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3759 } else { 3760 struct dl_serpath *s_entry; 3761 3762 s_entry = arg->serpath; 3763 s_entry->dls_name = arg->strspace; 3764 s_entry->dls_flags = arg->flags; 3765 3766 strncpy(arg->strspace, dir, dirlen); 3767 arg->strspace[dirlen] = '\0'; 3768 3769 arg->strspace += dirlen + 1; 3770 arg->serpath++; 3771 } 3772 3773 return (NULL); 3774 } 3775 3776 static int 3777 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3778 { 3779 struct dl_serinfo _info; 3780 struct fill_search_info_args args; 3781 3782 args.request = RTLD_DI_SERINFOSIZE; 3783 args.serinfo = &_info; 3784 3785 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3786 _info.dls_cnt = 0; 3787 3788 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3789 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3790 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3791 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3792 if (!obj->z_nodeflib) 3793 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3794 3795 3796 if (request == RTLD_DI_SERINFOSIZE) { 3797 info->dls_size = _info.dls_size; 3798 info->dls_cnt = _info.dls_cnt; 3799 return (0); 3800 } 3801 3802 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3803 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3804 return (-1); 3805 } 3806 3807 args.request = RTLD_DI_SERINFO; 3808 args.serinfo = info; 3809 args.serpath = &info->dls_serpath[0]; 3810 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3811 3812 args.flags = LA_SER_RUNPATH; 3813 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3814 return (-1); 3815 3816 args.flags = LA_SER_LIBPATH; 3817 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3818 return (-1); 3819 3820 args.flags = LA_SER_RUNPATH; 3821 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3822 return (-1); 3823 3824 args.flags = LA_SER_CONFIG; 3825 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3826 != NULL) 3827 return (-1); 3828 3829 args.flags = LA_SER_DEFAULT; 3830 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3831 fill_search_info, NULL, &args) != NULL) 3832 return (-1); 3833 return (0); 3834 } 3835 3836 static int 3837 rtld_dirname(const char *path, char *bname) 3838 { 3839 const char *endp; 3840 3841 /* Empty or NULL string gets treated as "." */ 3842 if (path == NULL || *path == '\0') { 3843 bname[0] = '.'; 3844 bname[1] = '\0'; 3845 return (0); 3846 } 3847 3848 /* Strip trailing slashes */ 3849 endp = path + strlen(path) - 1; 3850 while (endp > path && *endp == '/') 3851 endp--; 3852 3853 /* Find the start of the dir */ 3854 while (endp > path && *endp != '/') 3855 endp--; 3856 3857 /* Either the dir is "/" or there are no slashes */ 3858 if (endp == path) { 3859 bname[0] = *endp == '/' ? '/' : '.'; 3860 bname[1] = '\0'; 3861 return (0); 3862 } else { 3863 do { 3864 endp--; 3865 } while (endp > path && *endp == '/'); 3866 } 3867 3868 if (endp - path + 2 > PATH_MAX) 3869 { 3870 _rtld_error("Filename is too long: %s", path); 3871 return(-1); 3872 } 3873 3874 strncpy(bname, path, endp - path + 1); 3875 bname[endp - path + 1] = '\0'; 3876 return (0); 3877 } 3878 3879 static int 3880 rtld_dirname_abs(const char *path, char *base) 3881 { 3882 char *last; 3883 3884 if (realpath(path, base) == NULL) 3885 return (-1); 3886 dbg("%s -> %s", path, base); 3887 last = strrchr(base, '/'); 3888 if (last == NULL) 3889 return (-1); 3890 if (last != base) 3891 *last = '\0'; 3892 return (0); 3893 } 3894 3895 static void 3896 linkmap_add(Obj_Entry *obj) 3897 { 3898 struct link_map *l = &obj->linkmap; 3899 struct link_map *prev; 3900 3901 obj->linkmap.l_name = obj->path; 3902 obj->linkmap.l_addr = obj->mapbase; 3903 obj->linkmap.l_ld = obj->dynamic; 3904 #ifdef __mips__ 3905 /* GDB needs load offset on MIPS to use the symbols */ 3906 obj->linkmap.l_offs = obj->relocbase; 3907 #endif 3908 3909 if (r_debug.r_map == NULL) { 3910 r_debug.r_map = l; 3911 return; 3912 } 3913 3914 /* 3915 * Scan to the end of the list, but not past the entry for the 3916 * dynamic linker, which we want to keep at the very end. 3917 */ 3918 for (prev = r_debug.r_map; 3919 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3920 prev = prev->l_next) 3921 ; 3922 3923 /* Link in the new entry. */ 3924 l->l_prev = prev; 3925 l->l_next = prev->l_next; 3926 if (l->l_next != NULL) 3927 l->l_next->l_prev = l; 3928 prev->l_next = l; 3929 } 3930 3931 static void 3932 linkmap_delete(Obj_Entry *obj) 3933 { 3934 struct link_map *l = &obj->linkmap; 3935 3936 if (l->l_prev == NULL) { 3937 if ((r_debug.r_map = l->l_next) != NULL) 3938 l->l_next->l_prev = NULL; 3939 return; 3940 } 3941 3942 if ((l->l_prev->l_next = l->l_next) != NULL) 3943 l->l_next->l_prev = l->l_prev; 3944 } 3945 3946 /* 3947 * Function for the debugger to set a breakpoint on to gain control. 3948 * 3949 * The two parameters allow the debugger to easily find and determine 3950 * what the runtime loader is doing and to whom it is doing it. 3951 * 3952 * When the loadhook trap is hit (r_debug_state, set at program 3953 * initialization), the arguments can be found on the stack: 3954 * 3955 * +8 struct link_map *m 3956 * +4 struct r_debug *rd 3957 * +0 RetAddr 3958 */ 3959 void 3960 r_debug_state(struct r_debug* rd, struct link_map *m) 3961 { 3962 /* 3963 * The following is a hack to force the compiler to emit calls to 3964 * this function, even when optimizing. If the function is empty, 3965 * the compiler is not obliged to emit any code for calls to it, 3966 * even when marked __noinline. However, gdb depends on those 3967 * calls being made. 3968 */ 3969 __compiler_membar(); 3970 } 3971 3972 /* 3973 * A function called after init routines have completed. This can be used to 3974 * break before a program's entry routine is called, and can be used when 3975 * main is not available in the symbol table. 3976 */ 3977 void 3978 _r_debug_postinit(struct link_map *m) 3979 { 3980 3981 /* See r_debug_state(). */ 3982 __compiler_membar(); 3983 } 3984 3985 static void 3986 release_object(Obj_Entry *obj) 3987 { 3988 3989 if (obj->holdcount > 0) { 3990 obj->unholdfree = true; 3991 return; 3992 } 3993 munmap(obj->mapbase, obj->mapsize); 3994 linkmap_delete(obj); 3995 obj_free(obj); 3996 } 3997 3998 /* 3999 * Get address of the pointer variable in the main program. 4000 * Prefer non-weak symbol over the weak one. 4001 */ 4002 static const void ** 4003 get_program_var_addr(const char *name, RtldLockState *lockstate) 4004 { 4005 SymLook req; 4006 DoneList donelist; 4007 4008 symlook_init(&req, name); 4009 req.lockstate = lockstate; 4010 donelist_init(&donelist); 4011 if (symlook_global(&req, &donelist) != 0) 4012 return (NULL); 4013 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4014 return ((const void **)make_function_pointer(req.sym_out, 4015 req.defobj_out)); 4016 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4017 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4018 else 4019 return ((const void **)(req.defobj_out->relocbase + 4020 req.sym_out->st_value)); 4021 } 4022 4023 /* 4024 * Set a pointer variable in the main program to the given value. This 4025 * is used to set key variables such as "environ" before any of the 4026 * init functions are called. 4027 */ 4028 static void 4029 set_program_var(const char *name, const void *value) 4030 { 4031 const void **addr; 4032 4033 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4034 dbg("\"%s\": *%p <-- %p", name, addr, value); 4035 *addr = value; 4036 } 4037 } 4038 4039 /* 4040 * Search the global objects, including dependencies and main object, 4041 * for the given symbol. 4042 */ 4043 static int 4044 symlook_global(SymLook *req, DoneList *donelist) 4045 { 4046 SymLook req1; 4047 const Objlist_Entry *elm; 4048 int res; 4049 4050 symlook_init_from_req(&req1, req); 4051 4052 /* Search all objects loaded at program start up. */ 4053 if (req->defobj_out == NULL || 4054 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4055 res = symlook_list(&req1, &list_main, donelist); 4056 if (res == 0 && (req->defobj_out == NULL || 4057 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4058 req->sym_out = req1.sym_out; 4059 req->defobj_out = req1.defobj_out; 4060 assert(req->defobj_out != NULL); 4061 } 4062 } 4063 4064 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4065 STAILQ_FOREACH(elm, &list_global, link) { 4066 if (req->defobj_out != NULL && 4067 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4068 break; 4069 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4070 if (res == 0 && (req->defobj_out == NULL || 4071 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4072 req->sym_out = req1.sym_out; 4073 req->defobj_out = req1.defobj_out; 4074 assert(req->defobj_out != NULL); 4075 } 4076 } 4077 4078 return (req->sym_out != NULL ? 0 : ESRCH); 4079 } 4080 4081 /* 4082 * Given a symbol name in a referencing object, find the corresponding 4083 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4084 * no definition was found. Returns a pointer to the Obj_Entry of the 4085 * defining object via the reference parameter DEFOBJ_OUT. 4086 */ 4087 static int 4088 symlook_default(SymLook *req, const Obj_Entry *refobj) 4089 { 4090 DoneList donelist; 4091 const Objlist_Entry *elm; 4092 SymLook req1; 4093 int res; 4094 4095 donelist_init(&donelist); 4096 symlook_init_from_req(&req1, req); 4097 4098 /* 4099 * Look first in the referencing object if linked symbolically, 4100 * and similarly handle protected symbols. 4101 */ 4102 res = symlook_obj(&req1, refobj); 4103 if (res == 0 && (refobj->symbolic || 4104 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4105 req->sym_out = req1.sym_out; 4106 req->defobj_out = req1.defobj_out; 4107 assert(req->defobj_out != NULL); 4108 } 4109 if (refobj->symbolic || req->defobj_out != NULL) 4110 donelist_check(&donelist, refobj); 4111 4112 symlook_global(req, &donelist); 4113 4114 /* Search all dlopened DAGs containing the referencing object. */ 4115 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4116 if (req->sym_out != NULL && 4117 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4118 break; 4119 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4120 if (res == 0 && (req->sym_out == NULL || 4121 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4122 req->sym_out = req1.sym_out; 4123 req->defobj_out = req1.defobj_out; 4124 assert(req->defobj_out != NULL); 4125 } 4126 } 4127 4128 /* 4129 * Search the dynamic linker itself, and possibly resolve the 4130 * symbol from there. This is how the application links to 4131 * dynamic linker services such as dlopen. 4132 */ 4133 if (req->sym_out == NULL || 4134 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4135 res = symlook_obj(&req1, &obj_rtld); 4136 if (res == 0) { 4137 req->sym_out = req1.sym_out; 4138 req->defobj_out = req1.defobj_out; 4139 assert(req->defobj_out != NULL); 4140 } 4141 } 4142 4143 return (req->sym_out != NULL ? 0 : ESRCH); 4144 } 4145 4146 static int 4147 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4148 { 4149 const Elf_Sym *def; 4150 const Obj_Entry *defobj; 4151 const Objlist_Entry *elm; 4152 SymLook req1; 4153 int res; 4154 4155 def = NULL; 4156 defobj = NULL; 4157 STAILQ_FOREACH(elm, objlist, link) { 4158 if (donelist_check(dlp, elm->obj)) 4159 continue; 4160 symlook_init_from_req(&req1, req); 4161 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4162 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4163 def = req1.sym_out; 4164 defobj = req1.defobj_out; 4165 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4166 break; 4167 } 4168 } 4169 } 4170 if (def != NULL) { 4171 req->sym_out = def; 4172 req->defobj_out = defobj; 4173 return (0); 4174 } 4175 return (ESRCH); 4176 } 4177 4178 /* 4179 * Search the chain of DAGS cointed to by the given Needed_Entry 4180 * for a symbol of the given name. Each DAG is scanned completely 4181 * before advancing to the next one. Returns a pointer to the symbol, 4182 * or NULL if no definition was found. 4183 */ 4184 static int 4185 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4186 { 4187 const Elf_Sym *def; 4188 const Needed_Entry *n; 4189 const Obj_Entry *defobj; 4190 SymLook req1; 4191 int res; 4192 4193 def = NULL; 4194 defobj = NULL; 4195 symlook_init_from_req(&req1, req); 4196 for (n = needed; n != NULL; n = n->next) { 4197 if (n->obj == NULL || 4198 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4199 continue; 4200 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4201 def = req1.sym_out; 4202 defobj = req1.defobj_out; 4203 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4204 break; 4205 } 4206 } 4207 if (def != NULL) { 4208 req->sym_out = def; 4209 req->defobj_out = defobj; 4210 return (0); 4211 } 4212 return (ESRCH); 4213 } 4214 4215 /* 4216 * Search the symbol table of a single shared object for a symbol of 4217 * the given name and version, if requested. Returns a pointer to the 4218 * symbol, or NULL if no definition was found. If the object is 4219 * filter, return filtered symbol from filtee. 4220 * 4221 * The symbol's hash value is passed in for efficiency reasons; that 4222 * eliminates many recomputations of the hash value. 4223 */ 4224 int 4225 symlook_obj(SymLook *req, const Obj_Entry *obj) 4226 { 4227 DoneList donelist; 4228 SymLook req1; 4229 int flags, res, mres; 4230 4231 /* 4232 * If there is at least one valid hash at this point, we prefer to 4233 * use the faster GNU version if available. 4234 */ 4235 if (obj->valid_hash_gnu) 4236 mres = symlook_obj1_gnu(req, obj); 4237 else if (obj->valid_hash_sysv) 4238 mres = symlook_obj1_sysv(req, obj); 4239 else 4240 return (EINVAL); 4241 4242 if (mres == 0) { 4243 if (obj->needed_filtees != NULL) { 4244 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4245 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4246 donelist_init(&donelist); 4247 symlook_init_from_req(&req1, req); 4248 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4249 if (res == 0) { 4250 req->sym_out = req1.sym_out; 4251 req->defobj_out = req1.defobj_out; 4252 } 4253 return (res); 4254 } 4255 if (obj->needed_aux_filtees != NULL) { 4256 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4257 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4258 donelist_init(&donelist); 4259 symlook_init_from_req(&req1, req); 4260 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4261 if (res == 0) { 4262 req->sym_out = req1.sym_out; 4263 req->defobj_out = req1.defobj_out; 4264 return (res); 4265 } 4266 } 4267 } 4268 return (mres); 4269 } 4270 4271 /* Symbol match routine common to both hash functions */ 4272 static bool 4273 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4274 const unsigned long symnum) 4275 { 4276 Elf_Versym verndx; 4277 const Elf_Sym *symp; 4278 const char *strp; 4279 4280 symp = obj->symtab + symnum; 4281 strp = obj->strtab + symp->st_name; 4282 4283 switch (ELF_ST_TYPE(symp->st_info)) { 4284 case STT_FUNC: 4285 case STT_NOTYPE: 4286 case STT_OBJECT: 4287 case STT_COMMON: 4288 case STT_GNU_IFUNC: 4289 if (symp->st_value == 0) 4290 return (false); 4291 /* fallthrough */ 4292 case STT_TLS: 4293 if (symp->st_shndx != SHN_UNDEF) 4294 break; 4295 #ifndef __mips__ 4296 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4297 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4298 break; 4299 /* fallthrough */ 4300 #endif 4301 default: 4302 return (false); 4303 } 4304 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4305 return (false); 4306 4307 if (req->ventry == NULL) { 4308 if (obj->versyms != NULL) { 4309 verndx = VER_NDX(obj->versyms[symnum]); 4310 if (verndx > obj->vernum) { 4311 _rtld_error( 4312 "%s: symbol %s references wrong version %d", 4313 obj->path, obj->strtab + symnum, verndx); 4314 return (false); 4315 } 4316 /* 4317 * If we are not called from dlsym (i.e. this 4318 * is a normal relocation from unversioned 4319 * binary), accept the symbol immediately if 4320 * it happens to have first version after this 4321 * shared object became versioned. Otherwise, 4322 * if symbol is versioned and not hidden, 4323 * remember it. If it is the only symbol with 4324 * this name exported by the shared object, it 4325 * will be returned as a match by the calling 4326 * function. If symbol is global (verndx < 2) 4327 * accept it unconditionally. 4328 */ 4329 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4330 verndx == VER_NDX_GIVEN) { 4331 result->sym_out = symp; 4332 return (true); 4333 } 4334 else if (verndx >= VER_NDX_GIVEN) { 4335 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4336 == 0) { 4337 if (result->vsymp == NULL) 4338 result->vsymp = symp; 4339 result->vcount++; 4340 } 4341 return (false); 4342 } 4343 } 4344 result->sym_out = symp; 4345 return (true); 4346 } 4347 if (obj->versyms == NULL) { 4348 if (object_match_name(obj, req->ventry->name)) { 4349 _rtld_error("%s: object %s should provide version %s " 4350 "for symbol %s", obj_rtld.path, obj->path, 4351 req->ventry->name, obj->strtab + symnum); 4352 return (false); 4353 } 4354 } else { 4355 verndx = VER_NDX(obj->versyms[symnum]); 4356 if (verndx > obj->vernum) { 4357 _rtld_error("%s: symbol %s references wrong version %d", 4358 obj->path, obj->strtab + symnum, verndx); 4359 return (false); 4360 } 4361 if (obj->vertab[verndx].hash != req->ventry->hash || 4362 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4363 /* 4364 * Version does not match. Look if this is a 4365 * global symbol and if it is not hidden. If 4366 * global symbol (verndx < 2) is available, 4367 * use it. Do not return symbol if we are 4368 * called by dlvsym, because dlvsym looks for 4369 * a specific version and default one is not 4370 * what dlvsym wants. 4371 */ 4372 if ((req->flags & SYMLOOK_DLSYM) || 4373 (verndx >= VER_NDX_GIVEN) || 4374 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4375 return (false); 4376 } 4377 } 4378 result->sym_out = symp; 4379 return (true); 4380 } 4381 4382 /* 4383 * Search for symbol using SysV hash function. 4384 * obj->buckets is known not to be NULL at this point; the test for this was 4385 * performed with the obj->valid_hash_sysv assignment. 4386 */ 4387 static int 4388 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4389 { 4390 unsigned long symnum; 4391 Sym_Match_Result matchres; 4392 4393 matchres.sym_out = NULL; 4394 matchres.vsymp = NULL; 4395 matchres.vcount = 0; 4396 4397 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4398 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4399 if (symnum >= obj->nchains) 4400 return (ESRCH); /* Bad object */ 4401 4402 if (matched_symbol(req, obj, &matchres, symnum)) { 4403 req->sym_out = matchres.sym_out; 4404 req->defobj_out = obj; 4405 return (0); 4406 } 4407 } 4408 if (matchres.vcount == 1) { 4409 req->sym_out = matchres.vsymp; 4410 req->defobj_out = obj; 4411 return (0); 4412 } 4413 return (ESRCH); 4414 } 4415 4416 /* Search for symbol using GNU hash function */ 4417 static int 4418 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4419 { 4420 Elf_Addr bloom_word; 4421 const Elf32_Word *hashval; 4422 Elf32_Word bucket; 4423 Sym_Match_Result matchres; 4424 unsigned int h1, h2; 4425 unsigned long symnum; 4426 4427 matchres.sym_out = NULL; 4428 matchres.vsymp = NULL; 4429 matchres.vcount = 0; 4430 4431 /* Pick right bitmask word from Bloom filter array */ 4432 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4433 obj->maskwords_bm_gnu]; 4434 4435 /* Calculate modulus word size of gnu hash and its derivative */ 4436 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4437 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4438 4439 /* Filter out the "definitely not in set" queries */ 4440 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4441 return (ESRCH); 4442 4443 /* Locate hash chain and corresponding value element*/ 4444 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4445 if (bucket == 0) 4446 return (ESRCH); 4447 hashval = &obj->chain_zero_gnu[bucket]; 4448 do { 4449 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4450 symnum = hashval - obj->chain_zero_gnu; 4451 if (matched_symbol(req, obj, &matchres, symnum)) { 4452 req->sym_out = matchres.sym_out; 4453 req->defobj_out = obj; 4454 return (0); 4455 } 4456 } 4457 } while ((*hashval++ & 1) == 0); 4458 if (matchres.vcount == 1) { 4459 req->sym_out = matchres.vsymp; 4460 req->defobj_out = obj; 4461 return (0); 4462 } 4463 return (ESRCH); 4464 } 4465 4466 static void 4467 trace_loaded_objects(Obj_Entry *obj) 4468 { 4469 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4470 int c; 4471 4472 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4473 main_local = ""; 4474 4475 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4476 fmt1 = "\t%o => %p (%x)\n"; 4477 4478 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4479 fmt2 = "\t%o (%x)\n"; 4480 4481 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4482 4483 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4484 Needed_Entry *needed; 4485 char *name, *path; 4486 bool is_lib; 4487 4488 if (obj->marker) 4489 continue; 4490 if (list_containers && obj->needed != NULL) 4491 rtld_printf("%s:\n", obj->path); 4492 for (needed = obj->needed; needed; needed = needed->next) { 4493 if (needed->obj != NULL) { 4494 if (needed->obj->traced && !list_containers) 4495 continue; 4496 needed->obj->traced = true; 4497 path = needed->obj->path; 4498 } else 4499 path = "not found"; 4500 4501 name = (char *)obj->strtab + needed->name; 4502 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4503 4504 fmt = is_lib ? fmt1 : fmt2; 4505 while ((c = *fmt++) != '\0') { 4506 switch (c) { 4507 default: 4508 rtld_putchar(c); 4509 continue; 4510 case '\\': 4511 switch (c = *fmt) { 4512 case '\0': 4513 continue; 4514 case 'n': 4515 rtld_putchar('\n'); 4516 break; 4517 case 't': 4518 rtld_putchar('\t'); 4519 break; 4520 } 4521 break; 4522 case '%': 4523 switch (c = *fmt) { 4524 case '\0': 4525 continue; 4526 case '%': 4527 default: 4528 rtld_putchar(c); 4529 break; 4530 case 'A': 4531 rtld_putstr(main_local); 4532 break; 4533 case 'a': 4534 rtld_putstr(obj_main->path); 4535 break; 4536 case 'o': 4537 rtld_putstr(name); 4538 break; 4539 #if 0 4540 case 'm': 4541 rtld_printf("%d", sodp->sod_major); 4542 break; 4543 case 'n': 4544 rtld_printf("%d", sodp->sod_minor); 4545 break; 4546 #endif 4547 case 'p': 4548 rtld_putstr(path); 4549 break; 4550 case 'x': 4551 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4552 0); 4553 break; 4554 } 4555 break; 4556 } 4557 ++fmt; 4558 } 4559 } 4560 } 4561 } 4562 4563 /* 4564 * Unload a dlopened object and its dependencies from memory and from 4565 * our data structures. It is assumed that the DAG rooted in the 4566 * object has already been unreferenced, and that the object has a 4567 * reference count of 0. 4568 */ 4569 static void 4570 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4571 { 4572 Obj_Entry marker, *obj, *next; 4573 4574 assert(root->refcount == 0); 4575 4576 /* 4577 * Pass over the DAG removing unreferenced objects from 4578 * appropriate lists. 4579 */ 4580 unlink_object(root); 4581 4582 /* Unmap all objects that are no longer referenced. */ 4583 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4584 next = TAILQ_NEXT(obj, next); 4585 if (obj->marker || obj->refcount != 0) 4586 continue; 4587 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4588 obj->mapsize, 0, obj->path); 4589 dbg("unloading \"%s\"", obj->path); 4590 /* 4591 * Unlink the object now to prevent new references from 4592 * being acquired while the bind lock is dropped in 4593 * recursive dlclose() invocations. 4594 */ 4595 TAILQ_REMOVE(&obj_list, obj, next); 4596 obj_count--; 4597 4598 if (obj->filtees_loaded) { 4599 if (next != NULL) { 4600 init_marker(&marker); 4601 TAILQ_INSERT_BEFORE(next, &marker, next); 4602 unload_filtees(obj, lockstate); 4603 next = TAILQ_NEXT(&marker, next); 4604 TAILQ_REMOVE(&obj_list, &marker, next); 4605 } else 4606 unload_filtees(obj, lockstate); 4607 } 4608 release_object(obj); 4609 } 4610 } 4611 4612 static void 4613 unlink_object(Obj_Entry *root) 4614 { 4615 Objlist_Entry *elm; 4616 4617 if (root->refcount == 0) { 4618 /* Remove the object from the RTLD_GLOBAL list. */ 4619 objlist_remove(&list_global, root); 4620 4621 /* Remove the object from all objects' DAG lists. */ 4622 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4623 objlist_remove(&elm->obj->dldags, root); 4624 if (elm->obj != root) 4625 unlink_object(elm->obj); 4626 } 4627 } 4628 } 4629 4630 static void 4631 ref_dag(Obj_Entry *root) 4632 { 4633 Objlist_Entry *elm; 4634 4635 assert(root->dag_inited); 4636 STAILQ_FOREACH(elm, &root->dagmembers, link) 4637 elm->obj->refcount++; 4638 } 4639 4640 static void 4641 unref_dag(Obj_Entry *root) 4642 { 4643 Objlist_Entry *elm; 4644 4645 assert(root->dag_inited); 4646 STAILQ_FOREACH(elm, &root->dagmembers, link) 4647 elm->obj->refcount--; 4648 } 4649 4650 /* 4651 * Common code for MD __tls_get_addr(). 4652 */ 4653 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4654 static void * 4655 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4656 { 4657 Elf_Addr *newdtv, *dtv; 4658 RtldLockState lockstate; 4659 int to_copy; 4660 4661 dtv = *dtvp; 4662 /* Check dtv generation in case new modules have arrived */ 4663 if (dtv[0] != tls_dtv_generation) { 4664 wlock_acquire(rtld_bind_lock, &lockstate); 4665 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4666 to_copy = dtv[1]; 4667 if (to_copy > tls_max_index) 4668 to_copy = tls_max_index; 4669 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4670 newdtv[0] = tls_dtv_generation; 4671 newdtv[1] = tls_max_index; 4672 free(dtv); 4673 lock_release(rtld_bind_lock, &lockstate); 4674 dtv = *dtvp = newdtv; 4675 } 4676 4677 /* Dynamically allocate module TLS if necessary */ 4678 if (dtv[index + 1] == 0) { 4679 /* Signal safe, wlock will block out signals. */ 4680 wlock_acquire(rtld_bind_lock, &lockstate); 4681 if (!dtv[index + 1]) 4682 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4683 lock_release(rtld_bind_lock, &lockstate); 4684 } 4685 return ((void *)(dtv[index + 1] + offset)); 4686 } 4687 4688 void * 4689 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4690 { 4691 Elf_Addr *dtv; 4692 4693 dtv = *dtvp; 4694 /* Check dtv generation in case new modules have arrived */ 4695 if (__predict_true(dtv[0] == tls_dtv_generation && 4696 dtv[index + 1] != 0)) 4697 return ((void *)(dtv[index + 1] + offset)); 4698 return (tls_get_addr_slow(dtvp, index, offset)); 4699 } 4700 4701 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4702 defined(__powerpc__) || defined(__riscv) 4703 4704 /* 4705 * Return pointer to allocated TLS block 4706 */ 4707 static void * 4708 get_tls_block_ptr(void *tcb, size_t tcbsize) 4709 { 4710 size_t extra_size, post_size, pre_size, tls_block_size; 4711 size_t tls_init_align; 4712 4713 tls_init_align = MAX(obj_main->tlsalign, 1); 4714 4715 /* Compute fragments sizes. */ 4716 extra_size = tcbsize - TLS_TCB_SIZE; 4717 post_size = calculate_tls_post_size(tls_init_align); 4718 tls_block_size = tcbsize + post_size; 4719 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4720 4721 return ((char *)tcb - pre_size - extra_size); 4722 } 4723 4724 /* 4725 * Allocate Static TLS using the Variant I method. 4726 * 4727 * For details on the layout, see lib/libc/gen/tls.c. 4728 * 4729 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4730 * it is based on tls_last_offset, and TLS offsets here are really TCB 4731 * offsets, whereas libc's tls_static_space is just the executable's static 4732 * TLS segment. 4733 */ 4734 void * 4735 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4736 { 4737 Obj_Entry *obj; 4738 char *tls_block; 4739 Elf_Addr *dtv, **tcb; 4740 Elf_Addr addr; 4741 int i; 4742 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4743 size_t tls_init_align; 4744 4745 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4746 return (oldtcb); 4747 4748 assert(tcbsize >= TLS_TCB_SIZE); 4749 maxalign = MAX(tcbalign, tls_static_max_align); 4750 tls_init_align = MAX(obj_main->tlsalign, 1); 4751 4752 /* Compute fragmets sizes. */ 4753 extra_size = tcbsize - TLS_TCB_SIZE; 4754 post_size = calculate_tls_post_size(tls_init_align); 4755 tls_block_size = tcbsize + post_size; 4756 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4757 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4758 4759 /* Allocate whole TLS block */ 4760 tls_block = malloc_aligned(tls_block_size, maxalign); 4761 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4762 4763 if (oldtcb != NULL) { 4764 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4765 tls_static_space); 4766 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4767 4768 /* Adjust the DTV. */ 4769 dtv = tcb[0]; 4770 for (i = 0; i < dtv[1]; i++) { 4771 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4772 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4773 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4774 } 4775 } 4776 } else { 4777 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4778 tcb[0] = dtv; 4779 dtv[0] = tls_dtv_generation; 4780 dtv[1] = tls_max_index; 4781 4782 for (obj = globallist_curr(objs); obj != NULL; 4783 obj = globallist_next(obj)) { 4784 if (obj->tlsoffset > 0) { 4785 addr = (Elf_Addr)tcb + obj->tlsoffset; 4786 if (obj->tlsinitsize > 0) 4787 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4788 if (obj->tlssize > obj->tlsinitsize) 4789 memset((void*) (addr + obj->tlsinitsize), 0, 4790 obj->tlssize - obj->tlsinitsize); 4791 dtv[obj->tlsindex + 1] = addr; 4792 } 4793 } 4794 } 4795 4796 return (tcb); 4797 } 4798 4799 void 4800 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4801 { 4802 Elf_Addr *dtv; 4803 Elf_Addr tlsstart, tlsend; 4804 size_t post_size; 4805 size_t dtvsize, i, tls_init_align; 4806 4807 assert(tcbsize >= TLS_TCB_SIZE); 4808 tls_init_align = MAX(obj_main->tlsalign, 1); 4809 4810 /* Compute fragments sizes. */ 4811 post_size = calculate_tls_post_size(tls_init_align); 4812 4813 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4814 tlsend = (Elf_Addr)tcb + tls_static_space; 4815 4816 dtv = *(Elf_Addr **)tcb; 4817 dtvsize = dtv[1]; 4818 for (i = 0; i < dtvsize; i++) { 4819 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4820 free((void*)dtv[i+2]); 4821 } 4822 } 4823 free(dtv); 4824 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4825 } 4826 4827 #endif 4828 4829 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4830 4831 /* 4832 * Allocate Static TLS using the Variant II method. 4833 */ 4834 void * 4835 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4836 { 4837 Obj_Entry *obj; 4838 size_t size, ralign; 4839 char *tls; 4840 Elf_Addr *dtv, *olddtv; 4841 Elf_Addr segbase, oldsegbase, addr; 4842 int i; 4843 4844 ralign = tcbalign; 4845 if (tls_static_max_align > ralign) 4846 ralign = tls_static_max_align; 4847 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4848 4849 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4850 tls = malloc_aligned(size, ralign); 4851 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4852 4853 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4854 ((Elf_Addr*)segbase)[0] = segbase; 4855 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4856 4857 dtv[0] = tls_dtv_generation; 4858 dtv[1] = tls_max_index; 4859 4860 if (oldtls) { 4861 /* 4862 * Copy the static TLS block over whole. 4863 */ 4864 oldsegbase = (Elf_Addr) oldtls; 4865 memcpy((void *)(segbase - tls_static_space), 4866 (const void *)(oldsegbase - tls_static_space), 4867 tls_static_space); 4868 4869 /* 4870 * If any dynamic TLS blocks have been created tls_get_addr(), 4871 * move them over. 4872 */ 4873 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4874 for (i = 0; i < olddtv[1]; i++) { 4875 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4876 dtv[i+2] = olddtv[i+2]; 4877 olddtv[i+2] = 0; 4878 } 4879 } 4880 4881 /* 4882 * We assume that this block was the one we created with 4883 * allocate_initial_tls(). 4884 */ 4885 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4886 } else { 4887 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4888 if (obj->marker || obj->tlsoffset == 0) 4889 continue; 4890 addr = segbase - obj->tlsoffset; 4891 memset((void*) (addr + obj->tlsinitsize), 4892 0, obj->tlssize - obj->tlsinitsize); 4893 if (obj->tlsinit) 4894 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4895 dtv[obj->tlsindex + 1] = addr; 4896 } 4897 } 4898 4899 return (void*) segbase; 4900 } 4901 4902 void 4903 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4904 { 4905 Elf_Addr* dtv; 4906 size_t size, ralign; 4907 int dtvsize, i; 4908 Elf_Addr tlsstart, tlsend; 4909 4910 /* 4911 * Figure out the size of the initial TLS block so that we can 4912 * find stuff which ___tls_get_addr() allocated dynamically. 4913 */ 4914 ralign = tcbalign; 4915 if (tls_static_max_align > ralign) 4916 ralign = tls_static_max_align; 4917 size = round(tls_static_space, ralign); 4918 4919 dtv = ((Elf_Addr**)tls)[1]; 4920 dtvsize = dtv[1]; 4921 tlsend = (Elf_Addr) tls; 4922 tlsstart = tlsend - size; 4923 for (i = 0; i < dtvsize; i++) { 4924 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4925 free_aligned((void *)dtv[i + 2]); 4926 } 4927 } 4928 4929 free_aligned((void *)tlsstart); 4930 free((void*) dtv); 4931 } 4932 4933 #endif 4934 4935 /* 4936 * Allocate TLS block for module with given index. 4937 */ 4938 void * 4939 allocate_module_tls(int index) 4940 { 4941 Obj_Entry* obj; 4942 char* p; 4943 4944 TAILQ_FOREACH(obj, &obj_list, next) { 4945 if (obj->marker) 4946 continue; 4947 if (obj->tlsindex == index) 4948 break; 4949 } 4950 if (!obj) { 4951 _rtld_error("Can't find module with TLS index %d", index); 4952 rtld_die(); 4953 } 4954 4955 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4956 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4957 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4958 4959 return p; 4960 } 4961 4962 bool 4963 allocate_tls_offset(Obj_Entry *obj) 4964 { 4965 size_t off; 4966 4967 if (obj->tls_done) 4968 return true; 4969 4970 if (obj->tlssize == 0) { 4971 obj->tls_done = true; 4972 return true; 4973 } 4974 4975 if (tls_last_offset == 0) 4976 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4977 else 4978 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4979 obj->tlssize, obj->tlsalign); 4980 4981 /* 4982 * If we have already fixed the size of the static TLS block, we 4983 * must stay within that size. When allocating the static TLS, we 4984 * leave a small amount of space spare to be used for dynamically 4985 * loading modules which use static TLS. 4986 */ 4987 if (tls_static_space != 0) { 4988 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4989 return false; 4990 } else if (obj->tlsalign > tls_static_max_align) { 4991 tls_static_max_align = obj->tlsalign; 4992 } 4993 4994 tls_last_offset = obj->tlsoffset = off; 4995 tls_last_size = obj->tlssize; 4996 obj->tls_done = true; 4997 4998 return true; 4999 } 5000 5001 void 5002 free_tls_offset(Obj_Entry *obj) 5003 { 5004 5005 /* 5006 * If we were the last thing to allocate out of the static TLS 5007 * block, we give our space back to the 'allocator'. This is a 5008 * simplistic workaround to allow libGL.so.1 to be loaded and 5009 * unloaded multiple times. 5010 */ 5011 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5012 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5013 tls_last_offset -= obj->tlssize; 5014 tls_last_size = 0; 5015 } 5016 } 5017 5018 void * 5019 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5020 { 5021 void *ret; 5022 RtldLockState lockstate; 5023 5024 wlock_acquire(rtld_bind_lock, &lockstate); 5025 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5026 tcbsize, tcbalign); 5027 lock_release(rtld_bind_lock, &lockstate); 5028 return (ret); 5029 } 5030 5031 void 5032 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5033 { 5034 RtldLockState lockstate; 5035 5036 wlock_acquire(rtld_bind_lock, &lockstate); 5037 free_tls(tcb, tcbsize, tcbalign); 5038 lock_release(rtld_bind_lock, &lockstate); 5039 } 5040 5041 static void 5042 object_add_name(Obj_Entry *obj, const char *name) 5043 { 5044 Name_Entry *entry; 5045 size_t len; 5046 5047 len = strlen(name); 5048 entry = malloc(sizeof(Name_Entry) + len); 5049 5050 if (entry != NULL) { 5051 strcpy(entry->name, name); 5052 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5053 } 5054 } 5055 5056 static int 5057 object_match_name(const Obj_Entry *obj, const char *name) 5058 { 5059 Name_Entry *entry; 5060 5061 STAILQ_FOREACH(entry, &obj->names, link) { 5062 if (strcmp(name, entry->name) == 0) 5063 return (1); 5064 } 5065 return (0); 5066 } 5067 5068 static Obj_Entry * 5069 locate_dependency(const Obj_Entry *obj, const char *name) 5070 { 5071 const Objlist_Entry *entry; 5072 const Needed_Entry *needed; 5073 5074 STAILQ_FOREACH(entry, &list_main, link) { 5075 if (object_match_name(entry->obj, name)) 5076 return entry->obj; 5077 } 5078 5079 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5080 if (strcmp(obj->strtab + needed->name, name) == 0 || 5081 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5082 /* 5083 * If there is DT_NEEDED for the name we are looking for, 5084 * we are all set. Note that object might not be found if 5085 * dependency was not loaded yet, so the function can 5086 * return NULL here. This is expected and handled 5087 * properly by the caller. 5088 */ 5089 return (needed->obj); 5090 } 5091 } 5092 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5093 obj->path, name); 5094 rtld_die(); 5095 } 5096 5097 static int 5098 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5099 const Elf_Vernaux *vna) 5100 { 5101 const Elf_Verdef *vd; 5102 const char *vername; 5103 5104 vername = refobj->strtab + vna->vna_name; 5105 vd = depobj->verdef; 5106 if (vd == NULL) { 5107 _rtld_error("%s: version %s required by %s not defined", 5108 depobj->path, vername, refobj->path); 5109 return (-1); 5110 } 5111 for (;;) { 5112 if (vd->vd_version != VER_DEF_CURRENT) { 5113 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5114 depobj->path, vd->vd_version); 5115 return (-1); 5116 } 5117 if (vna->vna_hash == vd->vd_hash) { 5118 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5119 ((char *)vd + vd->vd_aux); 5120 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5121 return (0); 5122 } 5123 if (vd->vd_next == 0) 5124 break; 5125 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5126 } 5127 if (vna->vna_flags & VER_FLG_WEAK) 5128 return (0); 5129 _rtld_error("%s: version %s required by %s not found", 5130 depobj->path, vername, refobj->path); 5131 return (-1); 5132 } 5133 5134 static int 5135 rtld_verify_object_versions(Obj_Entry *obj) 5136 { 5137 const Elf_Verneed *vn; 5138 const Elf_Verdef *vd; 5139 const Elf_Verdaux *vda; 5140 const Elf_Vernaux *vna; 5141 const Obj_Entry *depobj; 5142 int maxvernum, vernum; 5143 5144 if (obj->ver_checked) 5145 return (0); 5146 obj->ver_checked = true; 5147 5148 maxvernum = 0; 5149 /* 5150 * Walk over defined and required version records and figure out 5151 * max index used by any of them. Do very basic sanity checking 5152 * while there. 5153 */ 5154 vn = obj->verneed; 5155 while (vn != NULL) { 5156 if (vn->vn_version != VER_NEED_CURRENT) { 5157 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5158 obj->path, vn->vn_version); 5159 return (-1); 5160 } 5161 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5162 for (;;) { 5163 vernum = VER_NEED_IDX(vna->vna_other); 5164 if (vernum > maxvernum) 5165 maxvernum = vernum; 5166 if (vna->vna_next == 0) 5167 break; 5168 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5169 } 5170 if (vn->vn_next == 0) 5171 break; 5172 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5173 } 5174 5175 vd = obj->verdef; 5176 while (vd != NULL) { 5177 if (vd->vd_version != VER_DEF_CURRENT) { 5178 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5179 obj->path, vd->vd_version); 5180 return (-1); 5181 } 5182 vernum = VER_DEF_IDX(vd->vd_ndx); 5183 if (vernum > maxvernum) 5184 maxvernum = vernum; 5185 if (vd->vd_next == 0) 5186 break; 5187 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5188 } 5189 5190 if (maxvernum == 0) 5191 return (0); 5192 5193 /* 5194 * Store version information in array indexable by version index. 5195 * Verify that object version requirements are satisfied along the 5196 * way. 5197 */ 5198 obj->vernum = maxvernum + 1; 5199 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5200 5201 vd = obj->verdef; 5202 while (vd != NULL) { 5203 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5204 vernum = VER_DEF_IDX(vd->vd_ndx); 5205 assert(vernum <= maxvernum); 5206 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5207 obj->vertab[vernum].hash = vd->vd_hash; 5208 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5209 obj->vertab[vernum].file = NULL; 5210 obj->vertab[vernum].flags = 0; 5211 } 5212 if (vd->vd_next == 0) 5213 break; 5214 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5215 } 5216 5217 vn = obj->verneed; 5218 while (vn != NULL) { 5219 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5220 if (depobj == NULL) 5221 return (-1); 5222 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5223 for (;;) { 5224 if (check_object_provided_version(obj, depobj, vna)) 5225 return (-1); 5226 vernum = VER_NEED_IDX(vna->vna_other); 5227 assert(vernum <= maxvernum); 5228 obj->vertab[vernum].hash = vna->vna_hash; 5229 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5230 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5231 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5232 VER_INFO_HIDDEN : 0; 5233 if (vna->vna_next == 0) 5234 break; 5235 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5236 } 5237 if (vn->vn_next == 0) 5238 break; 5239 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5240 } 5241 return 0; 5242 } 5243 5244 static int 5245 rtld_verify_versions(const Objlist *objlist) 5246 { 5247 Objlist_Entry *entry; 5248 int rc; 5249 5250 rc = 0; 5251 STAILQ_FOREACH(entry, objlist, link) { 5252 /* 5253 * Skip dummy objects or objects that have their version requirements 5254 * already checked. 5255 */ 5256 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5257 continue; 5258 if (rtld_verify_object_versions(entry->obj) == -1) { 5259 rc = -1; 5260 if (ld_tracing == NULL) 5261 break; 5262 } 5263 } 5264 if (rc == 0 || ld_tracing != NULL) 5265 rc = rtld_verify_object_versions(&obj_rtld); 5266 return rc; 5267 } 5268 5269 const Ver_Entry * 5270 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5271 { 5272 Elf_Versym vernum; 5273 5274 if (obj->vertab) { 5275 vernum = VER_NDX(obj->versyms[symnum]); 5276 if (vernum >= obj->vernum) { 5277 _rtld_error("%s: symbol %s has wrong verneed value %d", 5278 obj->path, obj->strtab + symnum, vernum); 5279 } else if (obj->vertab[vernum].hash != 0) { 5280 return &obj->vertab[vernum]; 5281 } 5282 } 5283 return NULL; 5284 } 5285 5286 int 5287 _rtld_get_stack_prot(void) 5288 { 5289 5290 return (stack_prot); 5291 } 5292 5293 int 5294 _rtld_is_dlopened(void *arg) 5295 { 5296 Obj_Entry *obj; 5297 RtldLockState lockstate; 5298 int res; 5299 5300 rlock_acquire(rtld_bind_lock, &lockstate); 5301 obj = dlcheck(arg); 5302 if (obj == NULL) 5303 obj = obj_from_addr(arg); 5304 if (obj == NULL) { 5305 _rtld_error("No shared object contains address"); 5306 lock_release(rtld_bind_lock, &lockstate); 5307 return (-1); 5308 } 5309 res = obj->dlopened ? 1 : 0; 5310 lock_release(rtld_bind_lock, &lockstate); 5311 return (res); 5312 } 5313 5314 static int 5315 obj_remap_relro(Obj_Entry *obj, int prot) 5316 { 5317 5318 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5319 prot) == -1) { 5320 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5321 obj->path, prot, rtld_strerror(errno)); 5322 return (-1); 5323 } 5324 return (0); 5325 } 5326 5327 static int 5328 obj_disable_relro(Obj_Entry *obj) 5329 { 5330 5331 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5332 } 5333 5334 static int 5335 obj_enforce_relro(Obj_Entry *obj) 5336 { 5337 5338 return (obj_remap_relro(obj, PROT_READ)); 5339 } 5340 5341 static void 5342 map_stacks_exec(RtldLockState *lockstate) 5343 { 5344 void (*thr_map_stacks_exec)(void); 5345 5346 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5347 return; 5348 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5349 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5350 if (thr_map_stacks_exec != NULL) { 5351 stack_prot |= PROT_EXEC; 5352 thr_map_stacks_exec(); 5353 } 5354 } 5355 5356 void 5357 symlook_init(SymLook *dst, const char *name) 5358 { 5359 5360 bzero(dst, sizeof(*dst)); 5361 dst->name = name; 5362 dst->hash = elf_hash(name); 5363 dst->hash_gnu = gnu_hash(name); 5364 } 5365 5366 static void 5367 symlook_init_from_req(SymLook *dst, const SymLook *src) 5368 { 5369 5370 dst->name = src->name; 5371 dst->hash = src->hash; 5372 dst->hash_gnu = src->hash_gnu; 5373 dst->ventry = src->ventry; 5374 dst->flags = src->flags; 5375 dst->defobj_out = NULL; 5376 dst->sym_out = NULL; 5377 dst->lockstate = src->lockstate; 5378 } 5379 5380 static int 5381 open_binary_fd(const char *argv0, bool search_in_path) 5382 { 5383 char *pathenv, *pe, binpath[PATH_MAX]; 5384 int fd; 5385 5386 if (search_in_path && strchr(argv0, '/') == NULL) { 5387 pathenv = getenv("PATH"); 5388 if (pathenv == NULL) { 5389 _rtld_error("-p and no PATH environment variable"); 5390 rtld_die(); 5391 } 5392 pathenv = strdup(pathenv); 5393 if (pathenv == NULL) { 5394 _rtld_error("Cannot allocate memory"); 5395 rtld_die(); 5396 } 5397 fd = -1; 5398 errno = ENOENT; 5399 while ((pe = strsep(&pathenv, ":")) != NULL) { 5400 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5401 sizeof(binpath)) 5402 continue; 5403 if (binpath[0] != '\0' && 5404 strlcat(binpath, "/", sizeof(binpath)) >= 5405 sizeof(binpath)) 5406 continue; 5407 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5408 sizeof(binpath)) 5409 continue; 5410 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5411 if (fd != -1 || errno != ENOENT) 5412 break; 5413 } 5414 free(pathenv); 5415 } else { 5416 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5417 } 5418 5419 if (fd == -1) { 5420 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5421 rtld_die(); 5422 } 5423 return (fd); 5424 } 5425 5426 /* 5427 * Parse a set of command-line arguments. 5428 */ 5429 static int 5430 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5431 { 5432 const char *arg; 5433 int fd, i, j, arglen; 5434 char opt; 5435 5436 dbg("Parsing command-line arguments"); 5437 *use_pathp = false; 5438 *fdp = -1; 5439 5440 for (i = 1; i < argc; i++ ) { 5441 arg = argv[i]; 5442 dbg("argv[%d]: '%s'", i, arg); 5443 5444 /* 5445 * rtld arguments end with an explicit "--" or with the first 5446 * non-prefixed argument. 5447 */ 5448 if (strcmp(arg, "--") == 0) { 5449 i++; 5450 break; 5451 } 5452 if (arg[0] != '-') 5453 break; 5454 5455 /* 5456 * All other arguments are single-character options that can 5457 * be combined, so we need to search through `arg` for them. 5458 */ 5459 arglen = strlen(arg); 5460 for (j = 1; j < arglen; j++) { 5461 opt = arg[j]; 5462 if (opt == 'h') { 5463 print_usage(argv[0]); 5464 _exit(0); 5465 } else if (opt == 'f') { 5466 /* 5467 * -f XX can be used to specify a descriptor for the 5468 * binary named at the command line (i.e., the later 5469 * argument will specify the process name but the 5470 * descriptor is what will actually be executed) 5471 */ 5472 if (j != arglen - 1) { 5473 /* -f must be the last option in, e.g., -abcf */ 5474 _rtld_error("Invalid options: %s", arg); 5475 rtld_die(); 5476 } 5477 i++; 5478 fd = parse_integer(argv[i]); 5479 if (fd == -1) { 5480 _rtld_error("Invalid file descriptor: '%s'", 5481 argv[i]); 5482 rtld_die(); 5483 } 5484 *fdp = fd; 5485 break; 5486 } else if (opt == 'p') { 5487 *use_pathp = true; 5488 } else { 5489 _rtld_error("Invalid argument: '%s'", arg); 5490 print_usage(argv[0]); 5491 rtld_die(); 5492 } 5493 } 5494 } 5495 5496 return (i); 5497 } 5498 5499 /* 5500 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5501 */ 5502 static int 5503 parse_integer(const char *str) 5504 { 5505 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5506 const char *orig; 5507 int n; 5508 char c; 5509 5510 orig = str; 5511 n = 0; 5512 for (c = *str; c != '\0'; c = *++str) { 5513 if (c < '0' || c > '9') 5514 return (-1); 5515 5516 n *= RADIX; 5517 n += c - '0'; 5518 } 5519 5520 /* Make sure we actually parsed something. */ 5521 if (str == orig) 5522 return (-1); 5523 return (n); 5524 } 5525 5526 static void 5527 print_usage(const char *argv0) 5528 { 5529 5530 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5531 "\n" 5532 "Options:\n" 5533 " -h Display this help message\n" 5534 " -p Search in PATH for named binary\n" 5535 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5536 " -- End of RTLD options\n" 5537 " <binary> Name of process to execute\n" 5538 " <args> Arguments to the executed process\n", argv0); 5539 } 5540 5541 /* 5542 * Overrides for libc_pic-provided functions. 5543 */ 5544 5545 int 5546 __getosreldate(void) 5547 { 5548 size_t len; 5549 int oid[2]; 5550 int error, osrel; 5551 5552 if (osreldate != 0) 5553 return (osreldate); 5554 5555 oid[0] = CTL_KERN; 5556 oid[1] = KERN_OSRELDATE; 5557 osrel = 0; 5558 len = sizeof(osrel); 5559 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5560 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5561 osreldate = osrel; 5562 return (osreldate); 5563 } 5564 5565 void 5566 exit(int status) 5567 { 5568 5569 _exit(status); 5570 } 5571 5572 void (*__cleanup)(void); 5573 int __isthreaded = 0; 5574 int _thread_autoinit_dummy_decl = 1; 5575 5576 /* 5577 * No unresolved symbols for rtld. 5578 */ 5579 void 5580 __pthread_cxa_finalize(struct dl_phdr_info *a) 5581 { 5582 } 5583 5584 const char * 5585 rtld_strerror(int errnum) 5586 { 5587 5588 if (errnum < 0 || errnum >= sys_nerr) 5589 return ("Unknown error"); 5590 return (sys_errlist[errnum]); 5591 } 5592 5593 /* 5594 * No ifunc relocations. 5595 */ 5596 void * 5597 memset(void *dest, int c, size_t len) 5598 { 5599 size_t i; 5600 5601 for (i = 0; i < len; i++) 5602 ((char *)dest)[i] = c; 5603 return (dest); 5604 } 5605 5606 void 5607 bzero(void *dest, size_t len) 5608 { 5609 size_t i; 5610 5611 for (i = 0; i < len; i++) 5612 ((char *)dest)[i] = 0; 5613 } 5614