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_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(void); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 78 /* Variables that cannot be static: */ 79 extern struct r_debug r_debug; /* For GDB */ 80 extern int _thread_autoinit_dummy_decl; 81 extern char* __progname; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static void digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static Obj_Entry *dlcheck(void *); 96 static int dlclose_locked(void *, RtldLockState *); 97 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 98 int lo_flags, int mode, RtldLockState *lockstate); 99 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 100 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 101 static bool donelist_check(DoneList *, const Obj_Entry *); 102 static void errmsg_restore(char *); 103 static char *errmsg_save(void); 104 static void *fill_search_info(const char *, size_t, void *); 105 static char *find_library(const char *, const Obj_Entry *, int *); 106 static const char *gethints(bool); 107 static void hold_object(Obj_Entry *); 108 static void unhold_object(Obj_Entry *); 109 static void init_dag(Obj_Entry *); 110 static void init_marker(Obj_Entry *); 111 static void init_pagesizes(Elf_Auxinfo **aux_info); 112 static void init_rtld(caddr_t, Elf_Auxinfo **); 113 static void initlist_add_neededs(Needed_Entry *, Objlist *); 114 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 115 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 116 static void linkmap_add(Obj_Entry *); 117 static void linkmap_delete(Obj_Entry *); 118 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 119 static void unload_filtees(Obj_Entry *, RtldLockState *); 120 static int load_needed_objects(Obj_Entry *, int); 121 static int load_preload_objects(void); 122 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 123 static void map_stacks_exec(RtldLockState *); 124 static int obj_disable_relro(Obj_Entry *); 125 static int obj_enforce_relro(Obj_Entry *); 126 static Obj_Entry *obj_from_addr(const void *); 127 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 128 static void objlist_call_init(Objlist *, RtldLockState *); 129 static void objlist_clear(Objlist *); 130 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 131 static void objlist_init(Objlist *); 132 static void objlist_push_head(Objlist *, Obj_Entry *); 133 static void objlist_push_tail(Objlist *, Obj_Entry *); 134 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 135 static void objlist_remove(Objlist *, Obj_Entry *); 136 static int open_binary_fd(const char *argv0, bool search_in_path); 137 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 138 static int parse_integer(const char *); 139 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 140 static void print_usage(const char *argv0); 141 static void release_object(Obj_Entry *); 142 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 143 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 144 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 145 int flags, RtldLockState *lockstate); 146 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 147 RtldLockState *); 148 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 149 static int rtld_dirname(const char *, char *); 150 static int rtld_dirname_abs(const char *, char *); 151 static void *rtld_dlopen(const char *name, int fd, int mode); 152 static void rtld_exit(void); 153 static char *search_library_path(const char *, const char *, const char *, 154 int *); 155 static char *search_library_pathfds(const char *, const char *, int *); 156 static const void **get_program_var_addr(const char *, RtldLockState *); 157 static void set_program_var(const char *, const void *); 158 static int symlook_default(SymLook *, const Obj_Entry *refobj); 159 static int symlook_global(SymLook *, DoneList *); 160 static void symlook_init_from_req(SymLook *, const SymLook *); 161 static int symlook_list(SymLook *, const Objlist *, DoneList *); 162 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 163 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 164 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 165 static void trace_loaded_objects(Obj_Entry *); 166 static void unlink_object(Obj_Entry *); 167 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 168 static void unref_dag(Obj_Entry *); 169 static void ref_dag(Obj_Entry *); 170 static char *origin_subst_one(Obj_Entry *, char *, const char *, 171 const char *, bool); 172 static char *origin_subst(Obj_Entry *, const char *); 173 static bool obj_resolve_origin(Obj_Entry *obj); 174 static void preinit_main(void); 175 static int rtld_verify_versions(const Objlist *); 176 static int rtld_verify_object_versions(Obj_Entry *); 177 static void object_add_name(Obj_Entry *, const char *); 178 static int object_match_name(const Obj_Entry *, const char *); 179 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 180 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 181 struct dl_phdr_info *phdr_info); 182 static uint32_t gnu_hash(const char *); 183 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 184 const unsigned long); 185 186 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 187 void _r_debug_postinit(struct link_map *) __noinline __exported; 188 189 int __sys_openat(int, const char *, int, ...); 190 191 /* 192 * Data declarations. 193 */ 194 static char *error_message; /* Message for dlerror(), or NULL */ 195 struct r_debug r_debug __exported; /* for GDB; */ 196 static bool libmap_disable; /* Disable libmap */ 197 static bool ld_loadfltr; /* Immediate filters processing */ 198 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 199 static bool trust; /* False for setuid and setgid programs */ 200 static bool dangerous_ld_env; /* True if environment variables have been 201 used to affect the libraries loaded */ 202 bool ld_bind_not; /* Disable PLT update */ 203 static char *ld_bind_now; /* Environment variable for immediate binding */ 204 static char *ld_debug; /* Environment variable for debugging */ 205 static char *ld_library_path; /* Environment variable for search path */ 206 static char *ld_library_dirs; /* Environment variable for library descriptors */ 207 static char *ld_preload; /* Environment variable for libraries to 208 load first */ 209 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 210 static const char *ld_tracing; /* Called from ldd to print libs */ 211 static char *ld_utrace; /* Use utrace() to log events. */ 212 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 213 static Obj_Entry *obj_main; /* The main program shared object */ 214 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 215 static unsigned int obj_count; /* Number of objects in obj_list */ 216 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 217 218 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 219 STAILQ_HEAD_INITIALIZER(list_global); 220 static Objlist list_main = /* Objects loaded at program startup */ 221 STAILQ_HEAD_INITIALIZER(list_main); 222 static Objlist list_fini = /* Objects needing fini() calls */ 223 STAILQ_HEAD_INITIALIZER(list_fini); 224 225 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 226 227 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 228 229 extern Elf_Dyn _DYNAMIC; 230 #pragma weak _DYNAMIC 231 232 int dlclose(void *) __exported; 233 char *dlerror(void) __exported; 234 void *dlopen(const char *, int) __exported; 235 void *fdlopen(int, int) __exported; 236 void *dlsym(void *, const char *) __exported; 237 dlfunc_t dlfunc(void *, const char *) __exported; 238 void *dlvsym(void *, const char *, const char *) __exported; 239 int dladdr(const void *, Dl_info *) __exported; 240 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 241 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 242 int dlinfo(void *, int , void *) __exported; 243 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 244 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 245 int _rtld_get_stack_prot(void) __exported; 246 int _rtld_is_dlopened(void *) __exported; 247 void _rtld_error(const char *, ...) __exported; 248 249 /* Only here to fix -Wmissing-prototypes warnings */ 250 int __getosreldate(void); 251 void __pthread_cxa_finalize(struct dl_phdr_info *a); 252 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 253 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 254 255 256 int npagesizes; 257 static int osreldate; 258 size_t *pagesizes; 259 260 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 261 static int max_stack_flags; 262 263 /* 264 * Global declarations normally provided by crt1. The dynamic linker is 265 * not built with crt1, so we have to provide them ourselves. 266 */ 267 char *__progname; 268 char **environ; 269 270 /* 271 * Used to pass argc, argv to init functions. 272 */ 273 int main_argc; 274 char **main_argv; 275 276 /* 277 * Globals to control TLS allocation. 278 */ 279 size_t tls_last_offset; /* Static TLS offset of last module */ 280 size_t tls_last_size; /* Static TLS size of last module */ 281 size_t tls_static_space; /* Static TLS space allocated */ 282 static size_t tls_static_max_align; 283 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 284 int tls_max_index = 1; /* Largest module index allocated */ 285 286 static bool ld_library_path_rpath = false; 287 288 /* 289 * Globals for path names, and such 290 */ 291 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 292 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 293 const char *ld_path_rtld = _PATH_RTLD; 294 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 295 const char *ld_env_prefix = LD_; 296 297 /* 298 * Fill in a DoneList with an allocation large enough to hold all of 299 * the currently-loaded objects. Keep this as a macro since it calls 300 * alloca and we want that to occur within the scope of the caller. 301 */ 302 #define donelist_init(dlp) \ 303 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 304 assert((dlp)->objs != NULL), \ 305 (dlp)->num_alloc = obj_count, \ 306 (dlp)->num_used = 0) 307 308 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 309 if (ld_utrace != NULL) \ 310 ld_utrace_log(e, h, mb, ms, r, n); \ 311 } while (0) 312 313 static void 314 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 315 int refcnt, const char *name) 316 { 317 struct utrace_rtld ut; 318 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 319 320 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 321 ut.event = event; 322 ut.handle = handle; 323 ut.mapbase = mapbase; 324 ut.mapsize = mapsize; 325 ut.refcnt = refcnt; 326 bzero(ut.name, sizeof(ut.name)); 327 if (name) 328 strlcpy(ut.name, name, sizeof(ut.name)); 329 utrace(&ut, sizeof(ut)); 330 } 331 332 #ifdef RTLD_VARIANT_ENV_NAMES 333 /* 334 * construct the env variable based on the type of binary that's 335 * running. 336 */ 337 static inline const char * 338 _LD(const char *var) 339 { 340 static char buffer[128]; 341 342 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 343 strlcat(buffer, var, sizeof(buffer)); 344 return (buffer); 345 } 346 #else 347 #define _LD(x) LD_ x 348 #endif 349 350 /* 351 * Main entry point for dynamic linking. The first argument is the 352 * stack pointer. The stack is expected to be laid out as described 353 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 354 * Specifically, the stack pointer points to a word containing 355 * ARGC. Following that in the stack is a null-terminated sequence 356 * of pointers to argument strings. Then comes a null-terminated 357 * sequence of pointers to environment strings. Finally, there is a 358 * sequence of "auxiliary vector" entries. 359 * 360 * The second argument points to a place to store the dynamic linker's 361 * exit procedure pointer and the third to a place to store the main 362 * program's object. 363 * 364 * The return value is the main program's entry point. 365 */ 366 func_ptr_type 367 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 368 { 369 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 370 Objlist_Entry *entry; 371 Obj_Entry *last_interposer, *obj, *preload_tail; 372 const Elf_Phdr *phdr; 373 Objlist initlist; 374 RtldLockState lockstate; 375 struct stat st; 376 Elf_Addr *argcp; 377 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 378 const char *argv0; 379 caddr_t imgentry; 380 char buf[MAXPATHLEN]; 381 int argc, fd, i, phnum, rtld_argc; 382 bool dir_enable, explicit_fd, search_in_path; 383 384 /* 385 * On entry, the dynamic linker itself has not been relocated yet. 386 * Be very careful not to reference any global data until after 387 * init_rtld has returned. It is OK to reference file-scope statics 388 * and string constants, and to call static and global functions. 389 */ 390 391 /* Find the auxiliary vector on the stack. */ 392 argcp = sp; 393 argc = *sp++; 394 argv = (char **) sp; 395 sp += argc + 1; /* Skip over arguments and NULL terminator */ 396 env = (char **) sp; 397 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 398 ; 399 aux = (Elf_Auxinfo *) sp; 400 401 /* Digest the auxiliary vector. */ 402 for (i = 0; i < AT_COUNT; i++) 403 aux_info[i] = NULL; 404 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 405 if (auxp->a_type < AT_COUNT) 406 aux_info[auxp->a_type] = auxp; 407 } 408 409 /* Initialize and relocate ourselves. */ 410 assert(aux_info[AT_BASE] != NULL); 411 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 412 413 __progname = obj_rtld.path; 414 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 415 environ = env; 416 main_argc = argc; 417 main_argv = argv; 418 419 trust = !issetugid(); 420 421 md_abi_variant_hook(aux_info); 422 423 fd = -1; 424 if (aux_info[AT_EXECFD] != NULL) { 425 fd = aux_info[AT_EXECFD]->a_un.a_val; 426 } else { 427 assert(aux_info[AT_PHDR] != NULL); 428 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 429 if (phdr == obj_rtld.phdr) { 430 if (!trust) { 431 _rtld_error("Tainted process refusing to run binary %s", 432 argv0); 433 rtld_die(); 434 } 435 dbg("opening main program in direct exec mode"); 436 if (argc >= 2) { 437 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 438 argv0 = argv[rtld_argc]; 439 explicit_fd = (fd != -1); 440 if (!explicit_fd) 441 fd = open_binary_fd(argv0, search_in_path); 442 if (fstat(fd, &st) == -1) { 443 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 444 explicit_fd ? "user-provided descriptor" : argv0, 445 rtld_strerror(errno)); 446 rtld_die(); 447 } 448 449 /* 450 * Rough emulation of the permission checks done by 451 * execve(2), only Unix DACs are checked, ACLs are 452 * ignored. Preserve the semantic of disabling owner 453 * to execute if owner x bit is cleared, even if 454 * others x bit is enabled. 455 * mmap(2) does not allow to mmap with PROT_EXEC if 456 * binary' file comes from noexec mount. We cannot 457 * set VV_TEXT on the binary. 458 */ 459 dir_enable = false; 460 if (st.st_uid == geteuid()) { 461 if ((st.st_mode & S_IXUSR) != 0) 462 dir_enable = true; 463 } else if (st.st_gid == getegid()) { 464 if ((st.st_mode & S_IXGRP) != 0) 465 dir_enable = true; 466 } else if ((st.st_mode & S_IXOTH) != 0) { 467 dir_enable = true; 468 } 469 if (!dir_enable) { 470 _rtld_error("No execute permission for binary %s", 471 argv0); 472 rtld_die(); 473 } 474 475 /* 476 * For direct exec mode, argv[0] is the interpreter 477 * name, we must remove it and shift arguments left 478 * before invoking binary main. Since stack layout 479 * places environment pointers and aux vectors right 480 * after the terminating NULL, we must shift 481 * environment and aux as well. 482 */ 483 main_argc = argc - rtld_argc; 484 for (i = 0; i <= main_argc; i++) 485 argv[i] = argv[i + rtld_argc]; 486 *argcp -= rtld_argc; 487 environ = env = envp = argv + main_argc + 1; 488 do { 489 *envp = *(envp + rtld_argc); 490 envp++; 491 } while (*envp != NULL); 492 aux = auxp = (Elf_Auxinfo *)envp; 493 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 494 for (;; auxp++, auxpf++) { 495 *auxp = *auxpf; 496 if (auxp->a_type == AT_NULL) 497 break; 498 } 499 } else { 500 _rtld_error("No binary"); 501 rtld_die(); 502 } 503 } 504 } 505 506 ld_bind_now = getenv(_LD("BIND_NOW")); 507 508 /* 509 * If the process is tainted, then we un-set the dangerous environment 510 * variables. The process will be marked as tainted until setuid(2) 511 * is called. If any child process calls setuid(2) we do not want any 512 * future processes to honor the potentially un-safe variables. 513 */ 514 if (!trust) { 515 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 516 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 517 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 518 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 519 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 520 _rtld_error("environment corrupt; aborting"); 521 rtld_die(); 522 } 523 } 524 ld_debug = getenv(_LD("DEBUG")); 525 if (ld_bind_now == NULL) 526 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 527 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 528 libmap_override = getenv(_LD("LIBMAP")); 529 ld_library_path = getenv(_LD("LIBRARY_PATH")); 530 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 531 ld_preload = getenv(_LD("PRELOAD")); 532 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 533 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 534 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 535 if (library_path_rpath != NULL) { 536 if (library_path_rpath[0] == 'y' || 537 library_path_rpath[0] == 'Y' || 538 library_path_rpath[0] == '1') 539 ld_library_path_rpath = true; 540 else 541 ld_library_path_rpath = false; 542 } 543 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 544 (ld_library_path != NULL) || (ld_preload != NULL) || 545 (ld_elf_hints_path != NULL) || ld_loadfltr; 546 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 547 ld_utrace = getenv(_LD("UTRACE")); 548 549 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 550 ld_elf_hints_path = ld_elf_hints_default; 551 552 if (ld_debug != NULL && *ld_debug != '\0') 553 debug = 1; 554 dbg("%s is initialized, base address = %p", __progname, 555 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 556 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 557 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 558 559 dbg("initializing thread locks"); 560 lockdflt_init(); 561 562 /* 563 * Load the main program, or process its program header if it is 564 * already loaded. 565 */ 566 if (fd != -1) { /* Load the main program. */ 567 dbg("loading main program"); 568 obj_main = map_object(fd, argv0, NULL); 569 close(fd); 570 if (obj_main == NULL) 571 rtld_die(); 572 max_stack_flags = obj_main->stack_flags; 573 } else { /* Main program already loaded. */ 574 dbg("processing main program's program header"); 575 assert(aux_info[AT_PHDR] != NULL); 576 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 577 assert(aux_info[AT_PHNUM] != NULL); 578 phnum = aux_info[AT_PHNUM]->a_un.a_val; 579 assert(aux_info[AT_PHENT] != NULL); 580 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 581 assert(aux_info[AT_ENTRY] != NULL); 582 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 583 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 584 rtld_die(); 585 } 586 587 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 588 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 589 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 590 if (kexecpath[0] == '/') 591 obj_main->path = kexecpath; 592 else if (getcwd(buf, sizeof(buf)) == NULL || 593 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 594 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 595 obj_main->path = xstrdup(argv0); 596 else 597 obj_main->path = xstrdup(buf); 598 } else { 599 dbg("No AT_EXECPATH or direct exec"); 600 obj_main->path = xstrdup(argv0); 601 } 602 dbg("obj_main path %s", obj_main->path); 603 obj_main->mainprog = true; 604 605 if (aux_info[AT_STACKPROT] != NULL && 606 aux_info[AT_STACKPROT]->a_un.a_val != 0) 607 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 608 609 #ifndef COMPAT_32BIT 610 /* 611 * Get the actual dynamic linker pathname from the executable if 612 * possible. (It should always be possible.) That ensures that 613 * gdb will find the right dynamic linker even if a non-standard 614 * one is being used. 615 */ 616 if (obj_main->interp != NULL && 617 strcmp(obj_main->interp, obj_rtld.path) != 0) { 618 free(obj_rtld.path); 619 obj_rtld.path = xstrdup(obj_main->interp); 620 __progname = obj_rtld.path; 621 } 622 #endif 623 624 digest_dynamic(obj_main, 0); 625 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 626 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 627 obj_main->dynsymcount); 628 629 linkmap_add(obj_main); 630 linkmap_add(&obj_rtld); 631 632 /* Link the main program into the list of objects. */ 633 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 634 obj_count++; 635 obj_loads++; 636 637 /* Initialize a fake symbol for resolving undefined weak references. */ 638 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 639 sym_zero.st_shndx = SHN_UNDEF; 640 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 641 642 if (!libmap_disable) 643 libmap_disable = (bool)lm_init(libmap_override); 644 645 dbg("loading LD_PRELOAD libraries"); 646 if (load_preload_objects() == -1) 647 rtld_die(); 648 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 649 650 dbg("loading needed objects"); 651 if (load_needed_objects(obj_main, 0) == -1) 652 rtld_die(); 653 654 /* Make a list of all objects loaded at startup. */ 655 last_interposer = obj_main; 656 TAILQ_FOREACH(obj, &obj_list, next) { 657 if (obj->marker) 658 continue; 659 if (obj->z_interpose && obj != obj_main) { 660 objlist_put_after(&list_main, last_interposer, obj); 661 last_interposer = obj; 662 } else { 663 objlist_push_tail(&list_main, obj); 664 } 665 obj->refcount++; 666 } 667 668 dbg("checking for required versions"); 669 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 670 rtld_die(); 671 672 if (ld_tracing) { /* We're done */ 673 trace_loaded_objects(obj_main); 674 exit(0); 675 } 676 677 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 678 dump_relocations(obj_main); 679 exit (0); 680 } 681 682 /* 683 * Processing tls relocations requires having the tls offsets 684 * initialized. Prepare offsets before starting initial 685 * relocation processing. 686 */ 687 dbg("initializing initial thread local storage offsets"); 688 STAILQ_FOREACH(entry, &list_main, link) { 689 /* 690 * Allocate all the initial objects out of the static TLS 691 * block even if they didn't ask for it. 692 */ 693 allocate_tls_offset(entry->obj); 694 } 695 696 if (relocate_objects(obj_main, 697 ld_bind_now != NULL && *ld_bind_now != '\0', 698 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 699 rtld_die(); 700 701 dbg("doing copy relocations"); 702 if (do_copy_relocations(obj_main) == -1) 703 rtld_die(); 704 705 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 706 dump_relocations(obj_main); 707 exit (0); 708 } 709 710 ifunc_init(aux); 711 712 /* 713 * Setup TLS for main thread. This must be done after the 714 * relocations are processed, since tls initialization section 715 * might be the subject for relocations. 716 */ 717 dbg("initializing initial thread local storage"); 718 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 719 720 dbg("initializing key program variables"); 721 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 722 set_program_var("environ", env); 723 set_program_var("__elf_aux_vector", aux); 724 725 /* Make a list of init functions to call. */ 726 objlist_init(&initlist); 727 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 728 preload_tail, &initlist); 729 730 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 731 732 map_stacks_exec(NULL); 733 734 if (!obj_main->crt_no_init) { 735 /* 736 * Make sure we don't call the main program's init and fini 737 * functions for binaries linked with old crt1 which calls 738 * _init itself. 739 */ 740 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 741 obj_main->preinit_array = obj_main->init_array = 742 obj_main->fini_array = (Elf_Addr)NULL; 743 } 744 745 /* 746 * Execute MD initializers required before we call the objects' 747 * init functions. 748 */ 749 pre_init(); 750 751 wlock_acquire(rtld_bind_lock, &lockstate); 752 753 dbg("resolving ifuncs"); 754 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 755 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 756 rtld_die(); 757 758 if (obj_main->crt_no_init) 759 preinit_main(); 760 objlist_call_init(&initlist, &lockstate); 761 _r_debug_postinit(&obj_main->linkmap); 762 objlist_clear(&initlist); 763 dbg("loading filtees"); 764 TAILQ_FOREACH(obj, &obj_list, next) { 765 if (obj->marker) 766 continue; 767 if (ld_loadfltr || obj->z_loadfltr) 768 load_filtees(obj, 0, &lockstate); 769 } 770 771 dbg("enforcing main obj relro"); 772 if (obj_enforce_relro(obj_main) == -1) 773 rtld_die(); 774 775 lock_release(rtld_bind_lock, &lockstate); 776 777 dbg("transferring control to program entry point = %p", obj_main->entry); 778 779 /* Return the exit procedure and the program entry point. */ 780 *exit_proc = rtld_exit; 781 *objp = obj_main; 782 return (func_ptr_type) obj_main->entry; 783 } 784 785 void * 786 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 787 { 788 void *ptr; 789 Elf_Addr target; 790 791 ptr = (void *)make_function_pointer(def, obj); 792 target = call_ifunc_resolver(ptr); 793 return ((void *)target); 794 } 795 796 /* 797 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 798 * Changes to this function should be applied there as well. 799 */ 800 Elf_Addr 801 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 802 { 803 const Elf_Rel *rel; 804 const Elf_Sym *def; 805 const Obj_Entry *defobj; 806 Elf_Addr *where; 807 Elf_Addr target; 808 RtldLockState lockstate; 809 810 rlock_acquire(rtld_bind_lock, &lockstate); 811 if (sigsetjmp(lockstate.env, 0) != 0) 812 lock_upgrade(rtld_bind_lock, &lockstate); 813 if (obj->pltrel) 814 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 815 else 816 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 817 818 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 819 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 820 NULL, &lockstate); 821 if (def == NULL) 822 rtld_die(); 823 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 824 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 825 else 826 target = (Elf_Addr)(defobj->relocbase + def->st_value); 827 828 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 829 defobj->strtab + def->st_name, basename(obj->path), 830 (void *)target, basename(defobj->path)); 831 832 /* 833 * Write the new contents for the jmpslot. Note that depending on 834 * architecture, the value which we need to return back to the 835 * lazy binding trampoline may or may not be the target 836 * address. The value returned from reloc_jmpslot() is the value 837 * that the trampoline needs. 838 */ 839 target = reloc_jmpslot(where, target, defobj, obj, rel); 840 lock_release(rtld_bind_lock, &lockstate); 841 return target; 842 } 843 844 /* 845 * Error reporting function. Use it like printf. If formats the message 846 * into a buffer, and sets things up so that the next call to dlerror() 847 * will return the message. 848 */ 849 void 850 _rtld_error(const char *fmt, ...) 851 { 852 static char buf[512]; 853 va_list ap; 854 855 va_start(ap, fmt); 856 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 857 error_message = buf; 858 va_end(ap); 859 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 860 } 861 862 /* 863 * Return a dynamically-allocated copy of the current error message, if any. 864 */ 865 static char * 866 errmsg_save(void) 867 { 868 return error_message == NULL ? NULL : xstrdup(error_message); 869 } 870 871 /* 872 * Restore the current error message from a copy which was previously saved 873 * by errmsg_save(). The copy is freed. 874 */ 875 static void 876 errmsg_restore(char *saved_msg) 877 { 878 if (saved_msg == NULL) 879 error_message = NULL; 880 else { 881 _rtld_error("%s", saved_msg); 882 free(saved_msg); 883 } 884 } 885 886 static const char * 887 basename(const char *name) 888 { 889 const char *p = strrchr(name, '/'); 890 return p != NULL ? p + 1 : name; 891 } 892 893 static struct utsname uts; 894 895 static char * 896 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 897 const char *subst, bool may_free) 898 { 899 char *p, *p1, *res, *resp; 900 int subst_len, kw_len, subst_count, old_len, new_len; 901 902 kw_len = strlen(kw); 903 904 /* 905 * First, count the number of the keyword occurrences, to 906 * preallocate the final string. 907 */ 908 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 909 p1 = strstr(p, kw); 910 if (p1 == NULL) 911 break; 912 } 913 914 /* 915 * If the keyword is not found, just return. 916 * 917 * Return non-substituted string if resolution failed. We 918 * cannot do anything more reasonable, the failure mode of the 919 * caller is unresolved library anyway. 920 */ 921 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 922 return (may_free ? real : xstrdup(real)); 923 if (obj != NULL) 924 subst = obj->origin_path; 925 926 /* 927 * There is indeed something to substitute. Calculate the 928 * length of the resulting string, and allocate it. 929 */ 930 subst_len = strlen(subst); 931 old_len = strlen(real); 932 new_len = old_len + (subst_len - kw_len) * subst_count; 933 res = xmalloc(new_len + 1); 934 935 /* 936 * Now, execute the substitution loop. 937 */ 938 for (p = real, resp = res, *resp = '\0';;) { 939 p1 = strstr(p, kw); 940 if (p1 != NULL) { 941 /* Copy the prefix before keyword. */ 942 memcpy(resp, p, p1 - p); 943 resp += p1 - p; 944 /* Keyword replacement. */ 945 memcpy(resp, subst, subst_len); 946 resp += subst_len; 947 *resp = '\0'; 948 p = p1 + kw_len; 949 } else 950 break; 951 } 952 953 /* Copy to the end of string and finish. */ 954 strcat(resp, p); 955 if (may_free) 956 free(real); 957 return (res); 958 } 959 960 static char * 961 origin_subst(Obj_Entry *obj, const char *real) 962 { 963 char *res1, *res2, *res3, *res4; 964 965 if (obj == NULL || !trust) 966 return (xstrdup(real)); 967 if (uts.sysname[0] == '\0') { 968 if (uname(&uts) != 0) { 969 _rtld_error("utsname failed: %d", errno); 970 return (NULL); 971 } 972 } 973 /* __DECONST is safe here since without may_free real is unchanged */ 974 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 975 false); 976 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 977 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 978 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 979 return (res4); 980 } 981 982 void 983 rtld_die(void) 984 { 985 const char *msg = dlerror(); 986 987 if (msg == NULL) 988 msg = "Fatal error"; 989 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 990 rtld_fdputstr(STDERR_FILENO, msg); 991 rtld_fdputchar(STDERR_FILENO, '\n'); 992 _exit(1); 993 } 994 995 /* 996 * Process a shared object's DYNAMIC section, and save the important 997 * information in its Obj_Entry structure. 998 */ 999 static void 1000 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1001 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1002 { 1003 const Elf_Dyn *dynp; 1004 Needed_Entry **needed_tail = &obj->needed; 1005 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1006 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1007 const Elf_Hashelt *hashtab; 1008 const Elf32_Word *hashval; 1009 Elf32_Word bkt, nmaskwords; 1010 int bloom_size32; 1011 int plttype = DT_REL; 1012 1013 *dyn_rpath = NULL; 1014 *dyn_soname = NULL; 1015 *dyn_runpath = NULL; 1016 1017 obj->bind_now = false; 1018 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1019 switch (dynp->d_tag) { 1020 1021 case DT_REL: 1022 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1023 break; 1024 1025 case DT_RELSZ: 1026 obj->relsize = dynp->d_un.d_val; 1027 break; 1028 1029 case DT_RELENT: 1030 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1031 break; 1032 1033 case DT_JMPREL: 1034 obj->pltrel = (const Elf_Rel *) 1035 (obj->relocbase + dynp->d_un.d_ptr); 1036 break; 1037 1038 case DT_PLTRELSZ: 1039 obj->pltrelsize = dynp->d_un.d_val; 1040 break; 1041 1042 case DT_RELA: 1043 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1044 break; 1045 1046 case DT_RELASZ: 1047 obj->relasize = dynp->d_un.d_val; 1048 break; 1049 1050 case DT_RELAENT: 1051 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1052 break; 1053 1054 case DT_PLTREL: 1055 plttype = dynp->d_un.d_val; 1056 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1057 break; 1058 1059 case DT_SYMTAB: 1060 obj->symtab = (const Elf_Sym *) 1061 (obj->relocbase + dynp->d_un.d_ptr); 1062 break; 1063 1064 case DT_SYMENT: 1065 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1066 break; 1067 1068 case DT_STRTAB: 1069 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1070 break; 1071 1072 case DT_STRSZ: 1073 obj->strsize = dynp->d_un.d_val; 1074 break; 1075 1076 case DT_VERNEED: 1077 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1078 dynp->d_un.d_val); 1079 break; 1080 1081 case DT_VERNEEDNUM: 1082 obj->verneednum = dynp->d_un.d_val; 1083 break; 1084 1085 case DT_VERDEF: 1086 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1087 dynp->d_un.d_val); 1088 break; 1089 1090 case DT_VERDEFNUM: 1091 obj->verdefnum = dynp->d_un.d_val; 1092 break; 1093 1094 case DT_VERSYM: 1095 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1096 dynp->d_un.d_val); 1097 break; 1098 1099 case DT_HASH: 1100 { 1101 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1102 dynp->d_un.d_ptr); 1103 obj->nbuckets = hashtab[0]; 1104 obj->nchains = hashtab[1]; 1105 obj->buckets = hashtab + 2; 1106 obj->chains = obj->buckets + obj->nbuckets; 1107 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1108 obj->buckets != NULL; 1109 } 1110 break; 1111 1112 case DT_GNU_HASH: 1113 { 1114 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1115 dynp->d_un.d_ptr); 1116 obj->nbuckets_gnu = hashtab[0]; 1117 obj->symndx_gnu = hashtab[1]; 1118 nmaskwords = hashtab[2]; 1119 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1120 obj->maskwords_bm_gnu = nmaskwords - 1; 1121 obj->shift2_gnu = hashtab[3]; 1122 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1123 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1124 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1125 obj->symndx_gnu; 1126 /* Number of bitmask words is required to be power of 2 */ 1127 obj->valid_hash_gnu = powerof2(nmaskwords) && 1128 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1129 } 1130 break; 1131 1132 case DT_NEEDED: 1133 if (!obj->rtld) { 1134 Needed_Entry *nep = NEW(Needed_Entry); 1135 nep->name = dynp->d_un.d_val; 1136 nep->obj = NULL; 1137 nep->next = NULL; 1138 1139 *needed_tail = nep; 1140 needed_tail = &nep->next; 1141 } 1142 break; 1143 1144 case DT_FILTER: 1145 if (!obj->rtld) { 1146 Needed_Entry *nep = NEW(Needed_Entry); 1147 nep->name = dynp->d_un.d_val; 1148 nep->obj = NULL; 1149 nep->next = NULL; 1150 1151 *needed_filtees_tail = nep; 1152 needed_filtees_tail = &nep->next; 1153 } 1154 break; 1155 1156 case DT_AUXILIARY: 1157 if (!obj->rtld) { 1158 Needed_Entry *nep = NEW(Needed_Entry); 1159 nep->name = dynp->d_un.d_val; 1160 nep->obj = NULL; 1161 nep->next = NULL; 1162 1163 *needed_aux_filtees_tail = nep; 1164 needed_aux_filtees_tail = &nep->next; 1165 } 1166 break; 1167 1168 case DT_PLTGOT: 1169 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1170 break; 1171 1172 case DT_TEXTREL: 1173 obj->textrel = true; 1174 break; 1175 1176 case DT_SYMBOLIC: 1177 obj->symbolic = true; 1178 break; 1179 1180 case DT_RPATH: 1181 /* 1182 * We have to wait until later to process this, because we 1183 * might not have gotten the address of the string table yet. 1184 */ 1185 *dyn_rpath = dynp; 1186 break; 1187 1188 case DT_SONAME: 1189 *dyn_soname = dynp; 1190 break; 1191 1192 case DT_RUNPATH: 1193 *dyn_runpath = dynp; 1194 break; 1195 1196 case DT_INIT: 1197 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1198 break; 1199 1200 case DT_PREINIT_ARRAY: 1201 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1202 break; 1203 1204 case DT_PREINIT_ARRAYSZ: 1205 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1206 break; 1207 1208 case DT_INIT_ARRAY: 1209 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1210 break; 1211 1212 case DT_INIT_ARRAYSZ: 1213 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1214 break; 1215 1216 case DT_FINI: 1217 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1218 break; 1219 1220 case DT_FINI_ARRAY: 1221 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1222 break; 1223 1224 case DT_FINI_ARRAYSZ: 1225 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1226 break; 1227 1228 /* 1229 * Don't process DT_DEBUG on MIPS as the dynamic section 1230 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1231 */ 1232 1233 #ifndef __mips__ 1234 case DT_DEBUG: 1235 if (!early) 1236 dbg("Filling in DT_DEBUG entry"); 1237 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1238 break; 1239 #endif 1240 1241 case DT_FLAGS: 1242 if (dynp->d_un.d_val & DF_ORIGIN) 1243 obj->z_origin = true; 1244 if (dynp->d_un.d_val & DF_SYMBOLIC) 1245 obj->symbolic = true; 1246 if (dynp->d_un.d_val & DF_TEXTREL) 1247 obj->textrel = true; 1248 if (dynp->d_un.d_val & DF_BIND_NOW) 1249 obj->bind_now = true; 1250 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1251 ;*/ 1252 break; 1253 #ifdef __mips__ 1254 case DT_MIPS_LOCAL_GOTNO: 1255 obj->local_gotno = dynp->d_un.d_val; 1256 break; 1257 1258 case DT_MIPS_SYMTABNO: 1259 obj->symtabno = dynp->d_un.d_val; 1260 break; 1261 1262 case DT_MIPS_GOTSYM: 1263 obj->gotsym = dynp->d_un.d_val; 1264 break; 1265 1266 case DT_MIPS_RLD_MAP: 1267 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1268 break; 1269 1270 case DT_MIPS_PLTGOT: 1271 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1272 dynp->d_un.d_ptr); 1273 break; 1274 1275 #endif 1276 1277 #ifdef __powerpc64__ 1278 case DT_PPC64_GLINK: 1279 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1280 break; 1281 #endif 1282 1283 case DT_FLAGS_1: 1284 if (dynp->d_un.d_val & DF_1_NOOPEN) 1285 obj->z_noopen = true; 1286 if (dynp->d_un.d_val & DF_1_ORIGIN) 1287 obj->z_origin = true; 1288 if (dynp->d_un.d_val & DF_1_GLOBAL) 1289 obj->z_global = true; 1290 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1291 obj->bind_now = true; 1292 if (dynp->d_un.d_val & DF_1_NODELETE) 1293 obj->z_nodelete = true; 1294 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1295 obj->z_loadfltr = true; 1296 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1297 obj->z_interpose = true; 1298 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1299 obj->z_nodeflib = true; 1300 break; 1301 1302 default: 1303 if (!early) { 1304 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1305 (long)dynp->d_tag); 1306 } 1307 break; 1308 } 1309 } 1310 1311 obj->traced = false; 1312 1313 if (plttype == DT_RELA) { 1314 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1315 obj->pltrel = NULL; 1316 obj->pltrelasize = obj->pltrelsize; 1317 obj->pltrelsize = 0; 1318 } 1319 1320 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1321 if (obj->valid_hash_sysv) 1322 obj->dynsymcount = obj->nchains; 1323 else if (obj->valid_hash_gnu) { 1324 obj->dynsymcount = 0; 1325 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1326 if (obj->buckets_gnu[bkt] == 0) 1327 continue; 1328 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1329 do 1330 obj->dynsymcount++; 1331 while ((*hashval++ & 1u) == 0); 1332 } 1333 obj->dynsymcount += obj->symndx_gnu; 1334 } 1335 } 1336 1337 static bool 1338 obj_resolve_origin(Obj_Entry *obj) 1339 { 1340 1341 if (obj->origin_path != NULL) 1342 return (true); 1343 obj->origin_path = xmalloc(PATH_MAX); 1344 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1345 } 1346 1347 static void 1348 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1349 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1350 { 1351 1352 if (obj->z_origin && !obj_resolve_origin(obj)) 1353 rtld_die(); 1354 1355 if (dyn_runpath != NULL) { 1356 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1357 obj->runpath = origin_subst(obj, obj->runpath); 1358 } else if (dyn_rpath != NULL) { 1359 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1360 obj->rpath = origin_subst(obj, obj->rpath); 1361 } 1362 if (dyn_soname != NULL) 1363 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1364 } 1365 1366 static void 1367 digest_dynamic(Obj_Entry *obj, int early) 1368 { 1369 const Elf_Dyn *dyn_rpath; 1370 const Elf_Dyn *dyn_soname; 1371 const Elf_Dyn *dyn_runpath; 1372 1373 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1374 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1375 } 1376 1377 /* 1378 * Process a shared object's program header. This is used only for the 1379 * main program, when the kernel has already loaded the main program 1380 * into memory before calling the dynamic linker. It creates and 1381 * returns an Obj_Entry structure. 1382 */ 1383 static Obj_Entry * 1384 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1385 { 1386 Obj_Entry *obj; 1387 const Elf_Phdr *phlimit = phdr + phnum; 1388 const Elf_Phdr *ph; 1389 Elf_Addr note_start, note_end; 1390 int nsegs = 0; 1391 1392 obj = obj_new(); 1393 for (ph = phdr; ph < phlimit; ph++) { 1394 if (ph->p_type != PT_PHDR) 1395 continue; 1396 1397 obj->phdr = phdr; 1398 obj->phsize = ph->p_memsz; 1399 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1400 break; 1401 } 1402 1403 obj->stack_flags = PF_X | PF_R | PF_W; 1404 1405 for (ph = phdr; ph < phlimit; ph++) { 1406 switch (ph->p_type) { 1407 1408 case PT_INTERP: 1409 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1410 break; 1411 1412 case PT_LOAD: 1413 if (nsegs == 0) { /* First load segment */ 1414 obj->vaddrbase = trunc_page(ph->p_vaddr); 1415 obj->mapbase = obj->vaddrbase + obj->relocbase; 1416 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1417 obj->vaddrbase; 1418 } else { /* Last load segment */ 1419 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1420 obj->vaddrbase; 1421 } 1422 nsegs++; 1423 break; 1424 1425 case PT_DYNAMIC: 1426 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1427 break; 1428 1429 case PT_TLS: 1430 obj->tlsindex = 1; 1431 obj->tlssize = ph->p_memsz; 1432 obj->tlsalign = ph->p_align; 1433 obj->tlsinitsize = ph->p_filesz; 1434 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1435 break; 1436 1437 case PT_GNU_STACK: 1438 obj->stack_flags = ph->p_flags; 1439 break; 1440 1441 case PT_GNU_RELRO: 1442 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1443 obj->relro_size = round_page(ph->p_memsz); 1444 break; 1445 1446 case PT_NOTE: 1447 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1448 note_end = note_start + ph->p_filesz; 1449 digest_notes(obj, note_start, note_end); 1450 break; 1451 } 1452 } 1453 if (nsegs < 1) { 1454 _rtld_error("%s: too few PT_LOAD segments", path); 1455 return NULL; 1456 } 1457 1458 obj->entry = entry; 1459 return obj; 1460 } 1461 1462 void 1463 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1464 { 1465 const Elf_Note *note; 1466 const char *note_name; 1467 uintptr_t p; 1468 1469 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1470 note = (const Elf_Note *)((const char *)(note + 1) + 1471 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1472 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1473 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1474 note->n_descsz != sizeof(int32_t)) 1475 continue; 1476 if (note->n_type != NT_FREEBSD_ABI_TAG && 1477 note->n_type != NT_FREEBSD_FEATURE_CTL && 1478 note->n_type != NT_FREEBSD_NOINIT_TAG) 1479 continue; 1480 note_name = (const char *)(note + 1); 1481 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1482 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1483 continue; 1484 switch (note->n_type) { 1485 case NT_FREEBSD_ABI_TAG: 1486 /* FreeBSD osrel note */ 1487 p = (uintptr_t)(note + 1); 1488 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1489 obj->osrel = *(const int32_t *)(p); 1490 dbg("note osrel %d", obj->osrel); 1491 break; 1492 case NT_FREEBSD_FEATURE_CTL: 1493 /* FreeBSD ABI feature control note */ 1494 p = (uintptr_t)(note + 1); 1495 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1496 obj->fctl0 = *(const uint32_t *)(p); 1497 dbg("note fctl0 %#x", obj->fctl0); 1498 break; 1499 case NT_FREEBSD_NOINIT_TAG: 1500 /* FreeBSD 'crt does not call init' note */ 1501 obj->crt_no_init = true; 1502 dbg("note crt_no_init"); 1503 break; 1504 } 1505 } 1506 } 1507 1508 static Obj_Entry * 1509 dlcheck(void *handle) 1510 { 1511 Obj_Entry *obj; 1512 1513 TAILQ_FOREACH(obj, &obj_list, next) { 1514 if (obj == (Obj_Entry *) handle) 1515 break; 1516 } 1517 1518 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1519 _rtld_error("Invalid shared object handle %p", handle); 1520 return NULL; 1521 } 1522 return obj; 1523 } 1524 1525 /* 1526 * If the given object is already in the donelist, return true. Otherwise 1527 * add the object to the list and return false. 1528 */ 1529 static bool 1530 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1531 { 1532 unsigned int i; 1533 1534 for (i = 0; i < dlp->num_used; i++) 1535 if (dlp->objs[i] == obj) 1536 return true; 1537 /* 1538 * Our donelist allocation should always be sufficient. But if 1539 * our threads locking isn't working properly, more shared objects 1540 * could have been loaded since we allocated the list. That should 1541 * never happen, but we'll handle it properly just in case it does. 1542 */ 1543 if (dlp->num_used < dlp->num_alloc) 1544 dlp->objs[dlp->num_used++] = obj; 1545 return false; 1546 } 1547 1548 /* 1549 * Hash function for symbol table lookup. Don't even think about changing 1550 * this. It is specified by the System V ABI. 1551 */ 1552 unsigned long 1553 elf_hash(const char *name) 1554 { 1555 const unsigned char *p = (const unsigned char *) name; 1556 unsigned long h = 0; 1557 unsigned long g; 1558 1559 while (*p != '\0') { 1560 h = (h << 4) + *p++; 1561 if ((g = h & 0xf0000000) != 0) 1562 h ^= g >> 24; 1563 h &= ~g; 1564 } 1565 return h; 1566 } 1567 1568 /* 1569 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1570 * unsigned in case it's implemented with a wider type. 1571 */ 1572 static uint32_t 1573 gnu_hash(const char *s) 1574 { 1575 uint32_t h; 1576 unsigned char c; 1577 1578 h = 5381; 1579 for (c = *s; c != '\0'; c = *++s) 1580 h = h * 33 + c; 1581 return (h & 0xffffffff); 1582 } 1583 1584 1585 /* 1586 * Find the library with the given name, and return its full pathname. 1587 * The returned string is dynamically allocated. Generates an error 1588 * message and returns NULL if the library cannot be found. 1589 * 1590 * If the second argument is non-NULL, then it refers to an already- 1591 * loaded shared object, whose library search path will be searched. 1592 * 1593 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1594 * descriptor (which is close-on-exec) will be passed out via the third 1595 * argument. 1596 * 1597 * The search order is: 1598 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1599 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1600 * LD_LIBRARY_PATH 1601 * DT_RUNPATH in the referencing file 1602 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1603 * from list) 1604 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1605 * 1606 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1607 */ 1608 static char * 1609 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1610 { 1611 char *pathname, *refobj_path; 1612 const char *name; 1613 bool nodeflib, objgiven; 1614 1615 objgiven = refobj != NULL; 1616 1617 if (libmap_disable || !objgiven || 1618 (name = lm_find(refobj->path, xname)) == NULL) 1619 name = xname; 1620 1621 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1622 if (name[0] != '/' && !trust) { 1623 _rtld_error("Absolute pathname required " 1624 "for shared object \"%s\"", name); 1625 return (NULL); 1626 } 1627 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1628 __DECONST(char *, name))); 1629 } 1630 1631 dbg(" Searching for \"%s\"", name); 1632 refobj_path = objgiven ? refobj->path : NULL; 1633 1634 /* 1635 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1636 * back to pre-conforming behaviour if user requested so with 1637 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1638 * nodeflib. 1639 */ 1640 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1641 pathname = search_library_path(name, ld_library_path, 1642 refobj_path, fdp); 1643 if (pathname != NULL) 1644 return (pathname); 1645 if (refobj != NULL) { 1646 pathname = search_library_path(name, refobj->rpath, 1647 refobj_path, fdp); 1648 if (pathname != NULL) 1649 return (pathname); 1650 } 1651 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1652 if (pathname != NULL) 1653 return (pathname); 1654 pathname = search_library_path(name, gethints(false), 1655 refobj_path, fdp); 1656 if (pathname != NULL) 1657 return (pathname); 1658 pathname = search_library_path(name, ld_standard_library_path, 1659 refobj_path, fdp); 1660 if (pathname != NULL) 1661 return (pathname); 1662 } else { 1663 nodeflib = objgiven ? refobj->z_nodeflib : false; 1664 if (objgiven) { 1665 pathname = search_library_path(name, refobj->rpath, 1666 refobj->path, fdp); 1667 if (pathname != NULL) 1668 return (pathname); 1669 } 1670 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1671 pathname = search_library_path(name, obj_main->rpath, 1672 refobj_path, fdp); 1673 if (pathname != NULL) 1674 return (pathname); 1675 } 1676 pathname = search_library_path(name, ld_library_path, 1677 refobj_path, fdp); 1678 if (pathname != NULL) 1679 return (pathname); 1680 if (objgiven) { 1681 pathname = search_library_path(name, refobj->runpath, 1682 refobj_path, fdp); 1683 if (pathname != NULL) 1684 return (pathname); 1685 } 1686 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1687 if (pathname != NULL) 1688 return (pathname); 1689 pathname = search_library_path(name, gethints(nodeflib), 1690 refobj_path, fdp); 1691 if (pathname != NULL) 1692 return (pathname); 1693 if (objgiven && !nodeflib) { 1694 pathname = search_library_path(name, 1695 ld_standard_library_path, refobj_path, fdp); 1696 if (pathname != NULL) 1697 return (pathname); 1698 } 1699 } 1700 1701 if (objgiven && refobj->path != NULL) { 1702 _rtld_error("Shared object \"%s\" not found, " 1703 "required by \"%s\"", name, basename(refobj->path)); 1704 } else { 1705 _rtld_error("Shared object \"%s\" not found", name); 1706 } 1707 return (NULL); 1708 } 1709 1710 /* 1711 * Given a symbol number in a referencing object, find the corresponding 1712 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1713 * no definition was found. Returns a pointer to the Obj_Entry of the 1714 * defining object via the reference parameter DEFOBJ_OUT. 1715 */ 1716 const Elf_Sym * 1717 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1718 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1719 RtldLockState *lockstate) 1720 { 1721 const Elf_Sym *ref; 1722 const Elf_Sym *def; 1723 const Obj_Entry *defobj; 1724 const Ver_Entry *ve; 1725 SymLook req; 1726 const char *name; 1727 int res; 1728 1729 /* 1730 * If we have already found this symbol, get the information from 1731 * the cache. 1732 */ 1733 if (symnum >= refobj->dynsymcount) 1734 return NULL; /* Bad object */ 1735 if (cache != NULL && cache[symnum].sym != NULL) { 1736 *defobj_out = cache[symnum].obj; 1737 return cache[symnum].sym; 1738 } 1739 1740 ref = refobj->symtab + symnum; 1741 name = refobj->strtab + ref->st_name; 1742 def = NULL; 1743 defobj = NULL; 1744 ve = NULL; 1745 1746 /* 1747 * We don't have to do a full scale lookup if the symbol is local. 1748 * We know it will bind to the instance in this load module; to 1749 * which we already have a pointer (ie ref). By not doing a lookup, 1750 * we not only improve performance, but it also avoids unresolvable 1751 * symbols when local symbols are not in the hash table. This has 1752 * been seen with the ia64 toolchain. 1753 */ 1754 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1755 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1756 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1757 symnum); 1758 } 1759 symlook_init(&req, name); 1760 req.flags = flags; 1761 ve = req.ventry = fetch_ventry(refobj, symnum); 1762 req.lockstate = lockstate; 1763 res = symlook_default(&req, refobj); 1764 if (res == 0) { 1765 def = req.sym_out; 1766 defobj = req.defobj_out; 1767 } 1768 } else { 1769 def = ref; 1770 defobj = refobj; 1771 } 1772 1773 /* 1774 * If we found no definition and the reference is weak, treat the 1775 * symbol as having the value zero. 1776 */ 1777 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1778 def = &sym_zero; 1779 defobj = obj_main; 1780 } 1781 1782 if (def != NULL) { 1783 *defobj_out = defobj; 1784 /* Record the information in the cache to avoid subsequent lookups. */ 1785 if (cache != NULL) { 1786 cache[symnum].sym = def; 1787 cache[symnum].obj = defobj; 1788 } 1789 } else { 1790 if (refobj != &obj_rtld) 1791 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1792 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1793 } 1794 return def; 1795 } 1796 1797 /* 1798 * Return the search path from the ldconfig hints file, reading it if 1799 * necessary. If nostdlib is true, then the default search paths are 1800 * not added to result. 1801 * 1802 * Returns NULL if there are problems with the hints file, 1803 * or if the search path there is empty. 1804 */ 1805 static const char * 1806 gethints(bool nostdlib) 1807 { 1808 static char *filtered_path; 1809 static const char *hints; 1810 static struct elfhints_hdr hdr; 1811 struct fill_search_info_args sargs, hargs; 1812 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1813 struct dl_serpath *SLPpath, *hintpath; 1814 char *p; 1815 struct stat hint_stat; 1816 unsigned int SLPndx, hintndx, fndx, fcount; 1817 int fd; 1818 size_t flen; 1819 uint32_t dl; 1820 bool skip; 1821 1822 /* First call, read the hints file */ 1823 if (hints == NULL) { 1824 /* Keep from trying again in case the hints file is bad. */ 1825 hints = ""; 1826 1827 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1828 return (NULL); 1829 1830 /* 1831 * Check of hdr.dirlistlen value against type limit 1832 * intends to pacify static analyzers. Further 1833 * paranoia leads to checks that dirlist is fully 1834 * contained in the file range. 1835 */ 1836 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1837 hdr.magic != ELFHINTS_MAGIC || 1838 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1839 fstat(fd, &hint_stat) == -1) { 1840 cleanup1: 1841 close(fd); 1842 hdr.dirlistlen = 0; 1843 return (NULL); 1844 } 1845 dl = hdr.strtab; 1846 if (dl + hdr.dirlist < dl) 1847 goto cleanup1; 1848 dl += hdr.dirlist; 1849 if (dl + hdr.dirlistlen < dl) 1850 goto cleanup1; 1851 dl += hdr.dirlistlen; 1852 if (dl > hint_stat.st_size) 1853 goto cleanup1; 1854 p = xmalloc(hdr.dirlistlen + 1); 1855 if (pread(fd, p, hdr.dirlistlen + 1, 1856 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1857 p[hdr.dirlistlen] != '\0') { 1858 free(p); 1859 goto cleanup1; 1860 } 1861 hints = p; 1862 close(fd); 1863 } 1864 1865 /* 1866 * If caller agreed to receive list which includes the default 1867 * paths, we are done. Otherwise, if we still did not 1868 * calculated filtered result, do it now. 1869 */ 1870 if (!nostdlib) 1871 return (hints[0] != '\0' ? hints : NULL); 1872 if (filtered_path != NULL) 1873 goto filt_ret; 1874 1875 /* 1876 * Obtain the list of all configured search paths, and the 1877 * list of the default paths. 1878 * 1879 * First estimate the size of the results. 1880 */ 1881 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1882 smeta.dls_cnt = 0; 1883 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1884 hmeta.dls_cnt = 0; 1885 1886 sargs.request = RTLD_DI_SERINFOSIZE; 1887 sargs.serinfo = &smeta; 1888 hargs.request = RTLD_DI_SERINFOSIZE; 1889 hargs.serinfo = &hmeta; 1890 1891 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1892 &sargs); 1893 path_enumerate(hints, fill_search_info, NULL, &hargs); 1894 1895 SLPinfo = xmalloc(smeta.dls_size); 1896 hintinfo = xmalloc(hmeta.dls_size); 1897 1898 /* 1899 * Next fetch both sets of paths. 1900 */ 1901 sargs.request = RTLD_DI_SERINFO; 1902 sargs.serinfo = SLPinfo; 1903 sargs.serpath = &SLPinfo->dls_serpath[0]; 1904 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1905 1906 hargs.request = RTLD_DI_SERINFO; 1907 hargs.serinfo = hintinfo; 1908 hargs.serpath = &hintinfo->dls_serpath[0]; 1909 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1910 1911 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1912 &sargs); 1913 path_enumerate(hints, fill_search_info, NULL, &hargs); 1914 1915 /* 1916 * Now calculate the difference between two sets, by excluding 1917 * standard paths from the full set. 1918 */ 1919 fndx = 0; 1920 fcount = 0; 1921 filtered_path = xmalloc(hdr.dirlistlen + 1); 1922 hintpath = &hintinfo->dls_serpath[0]; 1923 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1924 skip = false; 1925 SLPpath = &SLPinfo->dls_serpath[0]; 1926 /* 1927 * Check each standard path against current. 1928 */ 1929 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1930 /* matched, skip the path */ 1931 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1932 skip = true; 1933 break; 1934 } 1935 } 1936 if (skip) 1937 continue; 1938 /* 1939 * Not matched against any standard path, add the path 1940 * to result. Separate consequtive paths with ':'. 1941 */ 1942 if (fcount > 0) { 1943 filtered_path[fndx] = ':'; 1944 fndx++; 1945 } 1946 fcount++; 1947 flen = strlen(hintpath->dls_name); 1948 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1949 fndx += flen; 1950 } 1951 filtered_path[fndx] = '\0'; 1952 1953 free(SLPinfo); 1954 free(hintinfo); 1955 1956 filt_ret: 1957 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1958 } 1959 1960 static void 1961 init_dag(Obj_Entry *root) 1962 { 1963 const Needed_Entry *needed; 1964 const Objlist_Entry *elm; 1965 DoneList donelist; 1966 1967 if (root->dag_inited) 1968 return; 1969 donelist_init(&donelist); 1970 1971 /* Root object belongs to own DAG. */ 1972 objlist_push_tail(&root->dldags, root); 1973 objlist_push_tail(&root->dagmembers, root); 1974 donelist_check(&donelist, root); 1975 1976 /* 1977 * Add dependencies of root object to DAG in breadth order 1978 * by exploiting the fact that each new object get added 1979 * to the tail of the dagmembers list. 1980 */ 1981 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1982 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1983 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1984 continue; 1985 objlist_push_tail(&needed->obj->dldags, root); 1986 objlist_push_tail(&root->dagmembers, needed->obj); 1987 } 1988 } 1989 root->dag_inited = true; 1990 } 1991 1992 static void 1993 init_marker(Obj_Entry *marker) 1994 { 1995 1996 bzero(marker, sizeof(*marker)); 1997 marker->marker = true; 1998 } 1999 2000 Obj_Entry * 2001 globallist_curr(const Obj_Entry *obj) 2002 { 2003 2004 for (;;) { 2005 if (obj == NULL) 2006 return (NULL); 2007 if (!obj->marker) 2008 return (__DECONST(Obj_Entry *, obj)); 2009 obj = TAILQ_PREV(obj, obj_entry_q, next); 2010 } 2011 } 2012 2013 Obj_Entry * 2014 globallist_next(const Obj_Entry *obj) 2015 { 2016 2017 for (;;) { 2018 obj = TAILQ_NEXT(obj, next); 2019 if (obj == NULL) 2020 return (NULL); 2021 if (!obj->marker) 2022 return (__DECONST(Obj_Entry *, obj)); 2023 } 2024 } 2025 2026 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2027 static void 2028 hold_object(Obj_Entry *obj) 2029 { 2030 2031 obj->holdcount++; 2032 } 2033 2034 static void 2035 unhold_object(Obj_Entry *obj) 2036 { 2037 2038 assert(obj->holdcount > 0); 2039 if (--obj->holdcount == 0 && obj->unholdfree) 2040 release_object(obj); 2041 } 2042 2043 static void 2044 process_z(Obj_Entry *root) 2045 { 2046 const Objlist_Entry *elm; 2047 Obj_Entry *obj; 2048 2049 /* 2050 * Walk over object DAG and process every dependent object 2051 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2052 * to grow their own DAG. 2053 * 2054 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2055 * symlook_global() to work. 2056 * 2057 * For DF_1_NODELETE, the DAG should have its reference upped. 2058 */ 2059 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2060 obj = elm->obj; 2061 if (obj == NULL) 2062 continue; 2063 if (obj->z_nodelete && !obj->ref_nodel) { 2064 dbg("obj %s -z nodelete", obj->path); 2065 init_dag(obj); 2066 ref_dag(obj); 2067 obj->ref_nodel = true; 2068 } 2069 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2070 dbg("obj %s -z global", obj->path); 2071 objlist_push_tail(&list_global, obj); 2072 init_dag(obj); 2073 } 2074 } 2075 } 2076 /* 2077 * Initialize the dynamic linker. The argument is the address at which 2078 * the dynamic linker has been mapped into memory. The primary task of 2079 * this function is to relocate the dynamic linker. 2080 */ 2081 static void 2082 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2083 { 2084 Obj_Entry objtmp; /* Temporary rtld object */ 2085 const Elf_Ehdr *ehdr; 2086 const Elf_Dyn *dyn_rpath; 2087 const Elf_Dyn *dyn_soname; 2088 const Elf_Dyn *dyn_runpath; 2089 2090 #ifdef RTLD_INIT_PAGESIZES_EARLY 2091 /* The page size is required by the dynamic memory allocator. */ 2092 init_pagesizes(aux_info); 2093 #endif 2094 2095 /* 2096 * Conjure up an Obj_Entry structure for the dynamic linker. 2097 * 2098 * The "path" member can't be initialized yet because string constants 2099 * cannot yet be accessed. Below we will set it correctly. 2100 */ 2101 memset(&objtmp, 0, sizeof(objtmp)); 2102 objtmp.path = NULL; 2103 objtmp.rtld = true; 2104 objtmp.mapbase = mapbase; 2105 #ifdef PIC 2106 objtmp.relocbase = mapbase; 2107 #endif 2108 2109 objtmp.dynamic = rtld_dynamic(&objtmp); 2110 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2111 assert(objtmp.needed == NULL); 2112 #if !defined(__mips__) 2113 /* MIPS has a bogus DT_TEXTREL. */ 2114 assert(!objtmp.textrel); 2115 #endif 2116 /* 2117 * Temporarily put the dynamic linker entry into the object list, so 2118 * that symbols can be found. 2119 */ 2120 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2121 2122 ehdr = (Elf_Ehdr *)mapbase; 2123 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2124 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2125 2126 /* Initialize the object list. */ 2127 TAILQ_INIT(&obj_list); 2128 2129 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2130 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2131 2132 #ifndef RTLD_INIT_PAGESIZES_EARLY 2133 /* The page size is required by the dynamic memory allocator. */ 2134 init_pagesizes(aux_info); 2135 #endif 2136 2137 if (aux_info[AT_OSRELDATE] != NULL) 2138 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2139 2140 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2141 2142 /* Replace the path with a dynamically allocated copy. */ 2143 obj_rtld.path = xstrdup(ld_path_rtld); 2144 2145 r_debug.r_brk = r_debug_state; 2146 r_debug.r_state = RT_CONSISTENT; 2147 } 2148 2149 /* 2150 * Retrieve the array of supported page sizes. The kernel provides the page 2151 * sizes in increasing order. 2152 */ 2153 static void 2154 init_pagesizes(Elf_Auxinfo **aux_info) 2155 { 2156 static size_t psa[MAXPAGESIZES]; 2157 int mib[2]; 2158 size_t len, size; 2159 2160 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2161 NULL) { 2162 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2163 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2164 } else { 2165 len = 2; 2166 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2167 size = sizeof(psa); 2168 else { 2169 /* As a fallback, retrieve the base page size. */ 2170 size = sizeof(psa[0]); 2171 if (aux_info[AT_PAGESZ] != NULL) { 2172 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2173 goto psa_filled; 2174 } else { 2175 mib[0] = CTL_HW; 2176 mib[1] = HW_PAGESIZE; 2177 len = 2; 2178 } 2179 } 2180 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2181 _rtld_error("sysctl for hw.pagesize(s) failed"); 2182 rtld_die(); 2183 } 2184 psa_filled: 2185 pagesizes = psa; 2186 } 2187 npagesizes = size / sizeof(pagesizes[0]); 2188 /* Discard any invalid entries at the end of the array. */ 2189 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2190 npagesizes--; 2191 } 2192 2193 /* 2194 * Add the init functions from a needed object list (and its recursive 2195 * needed objects) to "list". This is not used directly; it is a helper 2196 * function for initlist_add_objects(). The write lock must be held 2197 * when this function is called. 2198 */ 2199 static void 2200 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2201 { 2202 /* Recursively process the successor needed objects. */ 2203 if (needed->next != NULL) 2204 initlist_add_neededs(needed->next, list); 2205 2206 /* Process the current needed object. */ 2207 if (needed->obj != NULL) 2208 initlist_add_objects(needed->obj, needed->obj, list); 2209 } 2210 2211 /* 2212 * Scan all of the DAGs rooted in the range of objects from "obj" to 2213 * "tail" and add their init functions to "list". This recurses over 2214 * the DAGs and ensure the proper init ordering such that each object's 2215 * needed libraries are initialized before the object itself. At the 2216 * same time, this function adds the objects to the global finalization 2217 * list "list_fini" in the opposite order. The write lock must be 2218 * held when this function is called. 2219 */ 2220 static void 2221 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2222 { 2223 Obj_Entry *nobj; 2224 2225 if (obj->init_scanned || obj->init_done) 2226 return; 2227 obj->init_scanned = true; 2228 2229 /* Recursively process the successor objects. */ 2230 nobj = globallist_next(obj); 2231 if (nobj != NULL && obj != tail) 2232 initlist_add_objects(nobj, tail, list); 2233 2234 /* Recursively process the needed objects. */ 2235 if (obj->needed != NULL) 2236 initlist_add_neededs(obj->needed, list); 2237 if (obj->needed_filtees != NULL) 2238 initlist_add_neededs(obj->needed_filtees, list); 2239 if (obj->needed_aux_filtees != NULL) 2240 initlist_add_neededs(obj->needed_aux_filtees, list); 2241 2242 /* Add the object to the init list. */ 2243 objlist_push_tail(list, obj); 2244 2245 /* Add the object to the global fini list in the reverse order. */ 2246 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2247 && !obj->on_fini_list) { 2248 objlist_push_head(&list_fini, obj); 2249 obj->on_fini_list = true; 2250 } 2251 } 2252 2253 #ifndef FPTR_TARGET 2254 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2255 #endif 2256 2257 static void 2258 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2259 { 2260 Needed_Entry *needed, *needed1; 2261 2262 for (needed = n; needed != NULL; needed = needed->next) { 2263 if (needed->obj != NULL) { 2264 dlclose_locked(needed->obj, lockstate); 2265 needed->obj = NULL; 2266 } 2267 } 2268 for (needed = n; needed != NULL; needed = needed1) { 2269 needed1 = needed->next; 2270 free(needed); 2271 } 2272 } 2273 2274 static void 2275 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2276 { 2277 2278 free_needed_filtees(obj->needed_filtees, lockstate); 2279 obj->needed_filtees = NULL; 2280 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2281 obj->needed_aux_filtees = NULL; 2282 obj->filtees_loaded = false; 2283 } 2284 2285 static void 2286 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2287 RtldLockState *lockstate) 2288 { 2289 2290 for (; needed != NULL; needed = needed->next) { 2291 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2292 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2293 RTLD_LOCAL, lockstate); 2294 } 2295 } 2296 2297 static void 2298 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2299 { 2300 2301 lock_restart_for_upgrade(lockstate); 2302 if (!obj->filtees_loaded) { 2303 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2304 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2305 obj->filtees_loaded = true; 2306 } 2307 } 2308 2309 static int 2310 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2311 { 2312 Obj_Entry *obj1; 2313 2314 for (; needed != NULL; needed = needed->next) { 2315 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2316 flags & ~RTLD_LO_NOLOAD); 2317 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2318 return (-1); 2319 } 2320 return (0); 2321 } 2322 2323 /* 2324 * Given a shared object, traverse its list of needed objects, and load 2325 * each of them. Returns 0 on success. Generates an error message and 2326 * returns -1 on failure. 2327 */ 2328 static int 2329 load_needed_objects(Obj_Entry *first, int flags) 2330 { 2331 Obj_Entry *obj; 2332 2333 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2334 if (obj->marker) 2335 continue; 2336 if (process_needed(obj, obj->needed, flags) == -1) 2337 return (-1); 2338 } 2339 return (0); 2340 } 2341 2342 static int 2343 load_preload_objects(void) 2344 { 2345 char *p = ld_preload; 2346 Obj_Entry *obj; 2347 static const char delim[] = " \t:;"; 2348 2349 if (p == NULL) 2350 return 0; 2351 2352 p += strspn(p, delim); 2353 while (*p != '\0') { 2354 size_t len = strcspn(p, delim); 2355 char savech; 2356 2357 savech = p[len]; 2358 p[len] = '\0'; 2359 obj = load_object(p, -1, NULL, 0); 2360 if (obj == NULL) 2361 return -1; /* XXX - cleanup */ 2362 obj->z_interpose = true; 2363 p[len] = savech; 2364 p += len; 2365 p += strspn(p, delim); 2366 } 2367 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2368 return 0; 2369 } 2370 2371 static const char * 2372 printable_path(const char *path) 2373 { 2374 2375 return (path == NULL ? "<unknown>" : path); 2376 } 2377 2378 /* 2379 * Load a shared object into memory, if it is not already loaded. The 2380 * object may be specified by name or by user-supplied file descriptor 2381 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2382 * duplicate is. 2383 * 2384 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2385 * on failure. 2386 */ 2387 static Obj_Entry * 2388 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2389 { 2390 Obj_Entry *obj; 2391 int fd; 2392 struct stat sb; 2393 char *path; 2394 2395 fd = -1; 2396 if (name != NULL) { 2397 TAILQ_FOREACH(obj, &obj_list, next) { 2398 if (obj->marker || obj->doomed) 2399 continue; 2400 if (object_match_name(obj, name)) 2401 return (obj); 2402 } 2403 2404 path = find_library(name, refobj, &fd); 2405 if (path == NULL) 2406 return (NULL); 2407 } else 2408 path = NULL; 2409 2410 if (fd >= 0) { 2411 /* 2412 * search_library_pathfds() opens a fresh file descriptor for the 2413 * library, so there is no need to dup(). 2414 */ 2415 } else if (fd_u == -1) { 2416 /* 2417 * If we didn't find a match by pathname, or the name is not 2418 * supplied, open the file and check again by device and inode. 2419 * This avoids false mismatches caused by multiple links or ".." 2420 * in pathnames. 2421 * 2422 * To avoid a race, we open the file and use fstat() rather than 2423 * using stat(). 2424 */ 2425 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2426 _rtld_error("Cannot open \"%s\"", path); 2427 free(path); 2428 return (NULL); 2429 } 2430 } else { 2431 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2432 if (fd == -1) { 2433 _rtld_error("Cannot dup fd"); 2434 free(path); 2435 return (NULL); 2436 } 2437 } 2438 if (fstat(fd, &sb) == -1) { 2439 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2440 close(fd); 2441 free(path); 2442 return NULL; 2443 } 2444 TAILQ_FOREACH(obj, &obj_list, next) { 2445 if (obj->marker || obj->doomed) 2446 continue; 2447 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2448 break; 2449 } 2450 if (obj != NULL && name != NULL) { 2451 object_add_name(obj, name); 2452 free(path); 2453 close(fd); 2454 return obj; 2455 } 2456 if (flags & RTLD_LO_NOLOAD) { 2457 free(path); 2458 close(fd); 2459 return (NULL); 2460 } 2461 2462 /* First use of this object, so we must map it in */ 2463 obj = do_load_object(fd, name, path, &sb, flags); 2464 if (obj == NULL) 2465 free(path); 2466 close(fd); 2467 2468 return obj; 2469 } 2470 2471 static Obj_Entry * 2472 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2473 int flags) 2474 { 2475 Obj_Entry *obj; 2476 struct statfs fs; 2477 2478 /* 2479 * but first, make sure that environment variables haven't been 2480 * used to circumvent the noexec flag on a filesystem. 2481 */ 2482 if (dangerous_ld_env) { 2483 if (fstatfs(fd, &fs) != 0) { 2484 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2485 return NULL; 2486 } 2487 if (fs.f_flags & MNT_NOEXEC) { 2488 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2489 return NULL; 2490 } 2491 } 2492 dbg("loading \"%s\"", printable_path(path)); 2493 obj = map_object(fd, printable_path(path), sbp); 2494 if (obj == NULL) 2495 return NULL; 2496 2497 /* 2498 * If DT_SONAME is present in the object, digest_dynamic2 already 2499 * added it to the object names. 2500 */ 2501 if (name != NULL) 2502 object_add_name(obj, name); 2503 obj->path = path; 2504 digest_dynamic(obj, 0); 2505 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2506 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2507 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2508 RTLD_LO_DLOPEN) { 2509 dbg("refusing to load non-loadable \"%s\"", obj->path); 2510 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2511 munmap(obj->mapbase, obj->mapsize); 2512 obj_free(obj); 2513 return (NULL); 2514 } 2515 2516 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2517 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2518 obj_count++; 2519 obj_loads++; 2520 linkmap_add(obj); /* for GDB & dlinfo() */ 2521 max_stack_flags |= obj->stack_flags; 2522 2523 dbg(" %p .. %p: %s", obj->mapbase, 2524 obj->mapbase + obj->mapsize - 1, obj->path); 2525 if (obj->textrel) 2526 dbg(" WARNING: %s has impure text", obj->path); 2527 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2528 obj->path); 2529 2530 return obj; 2531 } 2532 2533 static Obj_Entry * 2534 obj_from_addr(const void *addr) 2535 { 2536 Obj_Entry *obj; 2537 2538 TAILQ_FOREACH(obj, &obj_list, next) { 2539 if (obj->marker) 2540 continue; 2541 if (addr < (void *) obj->mapbase) 2542 continue; 2543 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2544 return obj; 2545 } 2546 return NULL; 2547 } 2548 2549 static void 2550 preinit_main(void) 2551 { 2552 Elf_Addr *preinit_addr; 2553 int index; 2554 2555 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2556 if (preinit_addr == NULL) 2557 return; 2558 2559 for (index = 0; index < obj_main->preinit_array_num; index++) { 2560 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2561 dbg("calling preinit function for %s at %p", obj_main->path, 2562 (void *)preinit_addr[index]); 2563 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2564 0, 0, obj_main->path); 2565 call_init_pointer(obj_main, preinit_addr[index]); 2566 } 2567 } 2568 } 2569 2570 /* 2571 * Call the finalization functions for each of the objects in "list" 2572 * belonging to the DAG of "root" and referenced once. If NULL "root" 2573 * is specified, every finalization function will be called regardless 2574 * of the reference count and the list elements won't be freed. All of 2575 * the objects are expected to have non-NULL fini functions. 2576 */ 2577 static void 2578 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2579 { 2580 Objlist_Entry *elm; 2581 char *saved_msg; 2582 Elf_Addr *fini_addr; 2583 int index; 2584 2585 assert(root == NULL || root->refcount == 1); 2586 2587 if (root != NULL) 2588 root->doomed = true; 2589 2590 /* 2591 * Preserve the current error message since a fini function might 2592 * call into the dynamic linker and overwrite it. 2593 */ 2594 saved_msg = errmsg_save(); 2595 do { 2596 STAILQ_FOREACH(elm, list, link) { 2597 if (root != NULL && (elm->obj->refcount != 1 || 2598 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2599 continue; 2600 /* Remove object from fini list to prevent recursive invocation. */ 2601 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2602 /* Ensure that new references cannot be acquired. */ 2603 elm->obj->doomed = true; 2604 2605 hold_object(elm->obj); 2606 lock_release(rtld_bind_lock, lockstate); 2607 /* 2608 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2609 * When this happens, DT_FINI_ARRAY is processed first. 2610 */ 2611 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2612 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2613 for (index = elm->obj->fini_array_num - 1; index >= 0; 2614 index--) { 2615 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2616 dbg("calling fini function for %s at %p", 2617 elm->obj->path, (void *)fini_addr[index]); 2618 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2619 (void *)fini_addr[index], 0, 0, elm->obj->path); 2620 call_initfini_pointer(elm->obj, fini_addr[index]); 2621 } 2622 } 2623 } 2624 if (elm->obj->fini != (Elf_Addr)NULL) { 2625 dbg("calling fini function for %s at %p", elm->obj->path, 2626 (void *)elm->obj->fini); 2627 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2628 0, 0, elm->obj->path); 2629 call_initfini_pointer(elm->obj, elm->obj->fini); 2630 } 2631 wlock_acquire(rtld_bind_lock, lockstate); 2632 unhold_object(elm->obj); 2633 /* No need to free anything if process is going down. */ 2634 if (root != NULL) 2635 free(elm); 2636 /* 2637 * We must restart the list traversal after every fini call 2638 * because a dlclose() call from the fini function or from 2639 * another thread might have modified the reference counts. 2640 */ 2641 break; 2642 } 2643 } while (elm != NULL); 2644 errmsg_restore(saved_msg); 2645 } 2646 2647 /* 2648 * Call the initialization functions for each of the objects in 2649 * "list". All of the objects are expected to have non-NULL init 2650 * functions. 2651 */ 2652 static void 2653 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2654 { 2655 Objlist_Entry *elm; 2656 Obj_Entry *obj; 2657 char *saved_msg; 2658 Elf_Addr *init_addr; 2659 int index; 2660 2661 /* 2662 * Clean init_scanned flag so that objects can be rechecked and 2663 * possibly initialized earlier if any of vectors called below 2664 * cause the change by using dlopen. 2665 */ 2666 TAILQ_FOREACH(obj, &obj_list, next) { 2667 if (obj->marker) 2668 continue; 2669 obj->init_scanned = false; 2670 } 2671 2672 /* 2673 * Preserve the current error message since an init function might 2674 * call into the dynamic linker and overwrite it. 2675 */ 2676 saved_msg = errmsg_save(); 2677 STAILQ_FOREACH(elm, list, link) { 2678 if (elm->obj->init_done) /* Initialized early. */ 2679 continue; 2680 /* 2681 * Race: other thread might try to use this object before current 2682 * one completes the initialization. Not much can be done here 2683 * without better locking. 2684 */ 2685 elm->obj->init_done = true; 2686 hold_object(elm->obj); 2687 lock_release(rtld_bind_lock, lockstate); 2688 2689 /* 2690 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2691 * When this happens, DT_INIT is processed first. 2692 */ 2693 if (elm->obj->init != (Elf_Addr)NULL) { 2694 dbg("calling init function for %s at %p", elm->obj->path, 2695 (void *)elm->obj->init); 2696 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2697 0, 0, elm->obj->path); 2698 call_initfini_pointer(elm->obj, elm->obj->init); 2699 } 2700 init_addr = (Elf_Addr *)elm->obj->init_array; 2701 if (init_addr != NULL) { 2702 for (index = 0; index < elm->obj->init_array_num; index++) { 2703 if (init_addr[index] != 0 && init_addr[index] != 1) { 2704 dbg("calling init function for %s at %p", elm->obj->path, 2705 (void *)init_addr[index]); 2706 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2707 (void *)init_addr[index], 0, 0, elm->obj->path); 2708 call_init_pointer(elm->obj, init_addr[index]); 2709 } 2710 } 2711 } 2712 wlock_acquire(rtld_bind_lock, lockstate); 2713 unhold_object(elm->obj); 2714 } 2715 errmsg_restore(saved_msg); 2716 } 2717 2718 static void 2719 objlist_clear(Objlist *list) 2720 { 2721 Objlist_Entry *elm; 2722 2723 while (!STAILQ_EMPTY(list)) { 2724 elm = STAILQ_FIRST(list); 2725 STAILQ_REMOVE_HEAD(list, link); 2726 free(elm); 2727 } 2728 } 2729 2730 static Objlist_Entry * 2731 objlist_find(Objlist *list, const Obj_Entry *obj) 2732 { 2733 Objlist_Entry *elm; 2734 2735 STAILQ_FOREACH(elm, list, link) 2736 if (elm->obj == obj) 2737 return elm; 2738 return NULL; 2739 } 2740 2741 static void 2742 objlist_init(Objlist *list) 2743 { 2744 STAILQ_INIT(list); 2745 } 2746 2747 static void 2748 objlist_push_head(Objlist *list, Obj_Entry *obj) 2749 { 2750 Objlist_Entry *elm; 2751 2752 elm = NEW(Objlist_Entry); 2753 elm->obj = obj; 2754 STAILQ_INSERT_HEAD(list, elm, link); 2755 } 2756 2757 static void 2758 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2759 { 2760 Objlist_Entry *elm; 2761 2762 elm = NEW(Objlist_Entry); 2763 elm->obj = obj; 2764 STAILQ_INSERT_TAIL(list, elm, link); 2765 } 2766 2767 static void 2768 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2769 { 2770 Objlist_Entry *elm, *listelm; 2771 2772 STAILQ_FOREACH(listelm, list, link) { 2773 if (listelm->obj == listobj) 2774 break; 2775 } 2776 elm = NEW(Objlist_Entry); 2777 elm->obj = obj; 2778 if (listelm != NULL) 2779 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2780 else 2781 STAILQ_INSERT_TAIL(list, elm, link); 2782 } 2783 2784 static void 2785 objlist_remove(Objlist *list, Obj_Entry *obj) 2786 { 2787 Objlist_Entry *elm; 2788 2789 if ((elm = objlist_find(list, obj)) != NULL) { 2790 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2791 free(elm); 2792 } 2793 } 2794 2795 /* 2796 * Relocate dag rooted in the specified object. 2797 * Returns 0 on success, or -1 on failure. 2798 */ 2799 2800 static int 2801 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2802 int flags, RtldLockState *lockstate) 2803 { 2804 Objlist_Entry *elm; 2805 int error; 2806 2807 error = 0; 2808 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2809 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2810 lockstate); 2811 if (error == -1) 2812 break; 2813 } 2814 return (error); 2815 } 2816 2817 /* 2818 * Prepare for, or clean after, relocating an object marked with 2819 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2820 * segments are remapped read-write. After relocations are done, the 2821 * segment's permissions are returned back to the modes specified in 2822 * the phdrs. If any relocation happened, or always for wired 2823 * program, COW is triggered. 2824 */ 2825 static int 2826 reloc_textrel_prot(Obj_Entry *obj, bool before) 2827 { 2828 const Elf_Phdr *ph; 2829 void *base; 2830 size_t l, sz; 2831 int prot; 2832 2833 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2834 l--, ph++) { 2835 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2836 continue; 2837 base = obj->relocbase + trunc_page(ph->p_vaddr); 2838 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2839 trunc_page(ph->p_vaddr); 2840 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2841 if (mprotect(base, sz, prot) == -1) { 2842 _rtld_error("%s: Cannot write-%sable text segment: %s", 2843 obj->path, before ? "en" : "dis", 2844 rtld_strerror(errno)); 2845 return (-1); 2846 } 2847 } 2848 return (0); 2849 } 2850 2851 /* 2852 * Relocate single object. 2853 * Returns 0 on success, or -1 on failure. 2854 */ 2855 static int 2856 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2857 int flags, RtldLockState *lockstate) 2858 { 2859 2860 if (obj->relocated) 2861 return (0); 2862 obj->relocated = true; 2863 if (obj != rtldobj) 2864 dbg("relocating \"%s\"", obj->path); 2865 2866 if (obj->symtab == NULL || obj->strtab == NULL || 2867 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2868 _rtld_error("%s: Shared object has no run-time symbol table", 2869 obj->path); 2870 return (-1); 2871 } 2872 2873 /* There are relocations to the write-protected text segment. */ 2874 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2875 return (-1); 2876 2877 /* Process the non-PLT non-IFUNC relocations. */ 2878 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2879 return (-1); 2880 2881 /* Re-protected the text segment. */ 2882 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2883 return (-1); 2884 2885 /* Set the special PLT or GOT entries. */ 2886 init_pltgot(obj); 2887 2888 /* Process the PLT relocations. */ 2889 if (reloc_plt(obj, flags, lockstate) == -1) 2890 return (-1); 2891 /* Relocate the jump slots if we are doing immediate binding. */ 2892 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2893 lockstate) == -1) 2894 return (-1); 2895 2896 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2897 return (-1); 2898 2899 /* 2900 * Set up the magic number and version in the Obj_Entry. These 2901 * were checked in the crt1.o from the original ElfKit, so we 2902 * set them for backward compatibility. 2903 */ 2904 obj->magic = RTLD_MAGIC; 2905 obj->version = RTLD_VERSION; 2906 2907 return (0); 2908 } 2909 2910 /* 2911 * Relocate newly-loaded shared objects. The argument is a pointer to 2912 * the Obj_Entry for the first such object. All objects from the first 2913 * to the end of the list of objects are relocated. Returns 0 on success, 2914 * or -1 on failure. 2915 */ 2916 static int 2917 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2918 int flags, RtldLockState *lockstate) 2919 { 2920 Obj_Entry *obj; 2921 int error; 2922 2923 for (error = 0, obj = first; obj != NULL; 2924 obj = TAILQ_NEXT(obj, next)) { 2925 if (obj->marker) 2926 continue; 2927 error = relocate_object(obj, bind_now, rtldobj, flags, 2928 lockstate); 2929 if (error == -1) 2930 break; 2931 } 2932 return (error); 2933 } 2934 2935 /* 2936 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2937 * referencing STT_GNU_IFUNC symbols is postponed till the other 2938 * relocations are done. The indirect functions specified as 2939 * ifunc are allowed to call other symbols, so we need to have 2940 * objects relocated before asking for resolution from indirects. 2941 * 2942 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2943 * instead of the usual lazy handling of PLT slots. It is 2944 * consistent with how GNU does it. 2945 */ 2946 static int 2947 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2948 RtldLockState *lockstate) 2949 { 2950 2951 if (obj->ifuncs_resolved) 2952 return (0); 2953 obj->ifuncs_resolved = true; 2954 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2955 return (-1); 2956 if ((obj->bind_now || bind_now) && obj->gnu_ifunc) { 2957 if (obj_disable_relro(obj) || 2958 reloc_gnu_ifunc(obj, flags, lockstate) == -1 || 2959 obj_enforce_relro(obj)) 2960 return (-1); 2961 } 2962 return (0); 2963 } 2964 2965 static int 2966 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2967 RtldLockState *lockstate) 2968 { 2969 Objlist_Entry *elm; 2970 Obj_Entry *obj; 2971 2972 STAILQ_FOREACH(elm, list, link) { 2973 obj = elm->obj; 2974 if (obj->marker) 2975 continue; 2976 if (resolve_object_ifunc(obj, bind_now, flags, 2977 lockstate) == -1) 2978 return (-1); 2979 } 2980 return (0); 2981 } 2982 2983 /* 2984 * Cleanup procedure. It will be called (by the atexit mechanism) just 2985 * before the process exits. 2986 */ 2987 static void 2988 rtld_exit(void) 2989 { 2990 RtldLockState lockstate; 2991 2992 wlock_acquire(rtld_bind_lock, &lockstate); 2993 dbg("rtld_exit()"); 2994 objlist_call_fini(&list_fini, NULL, &lockstate); 2995 /* No need to remove the items from the list, since we are exiting. */ 2996 if (!libmap_disable) 2997 lm_fini(); 2998 lock_release(rtld_bind_lock, &lockstate); 2999 } 3000 3001 /* 3002 * Iterate over a search path, translate each element, and invoke the 3003 * callback on the result. 3004 */ 3005 static void * 3006 path_enumerate(const char *path, path_enum_proc callback, 3007 const char *refobj_path, void *arg) 3008 { 3009 const char *trans; 3010 if (path == NULL) 3011 return (NULL); 3012 3013 path += strspn(path, ":;"); 3014 while (*path != '\0') { 3015 size_t len; 3016 char *res; 3017 3018 len = strcspn(path, ":;"); 3019 trans = lm_findn(refobj_path, path, len); 3020 if (trans) 3021 res = callback(trans, strlen(trans), arg); 3022 else 3023 res = callback(path, len, arg); 3024 3025 if (res != NULL) 3026 return (res); 3027 3028 path += len; 3029 path += strspn(path, ":;"); 3030 } 3031 3032 return (NULL); 3033 } 3034 3035 struct try_library_args { 3036 const char *name; 3037 size_t namelen; 3038 char *buffer; 3039 size_t buflen; 3040 int fd; 3041 }; 3042 3043 static void * 3044 try_library_path(const char *dir, size_t dirlen, void *param) 3045 { 3046 struct try_library_args *arg; 3047 int fd; 3048 3049 arg = param; 3050 if (*dir == '/' || trust) { 3051 char *pathname; 3052 3053 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3054 return (NULL); 3055 3056 pathname = arg->buffer; 3057 strncpy(pathname, dir, dirlen); 3058 pathname[dirlen] = '/'; 3059 strcpy(pathname + dirlen + 1, arg->name); 3060 3061 dbg(" Trying \"%s\"", pathname); 3062 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3063 if (fd >= 0) { 3064 dbg(" Opened \"%s\", fd %d", pathname, fd); 3065 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3066 strcpy(pathname, arg->buffer); 3067 arg->fd = fd; 3068 return (pathname); 3069 } else { 3070 dbg(" Failed to open \"%s\": %s", 3071 pathname, rtld_strerror(errno)); 3072 } 3073 } 3074 return (NULL); 3075 } 3076 3077 static char * 3078 search_library_path(const char *name, const char *path, 3079 const char *refobj_path, int *fdp) 3080 { 3081 char *p; 3082 struct try_library_args arg; 3083 3084 if (path == NULL) 3085 return NULL; 3086 3087 arg.name = name; 3088 arg.namelen = strlen(name); 3089 arg.buffer = xmalloc(PATH_MAX); 3090 arg.buflen = PATH_MAX; 3091 arg.fd = -1; 3092 3093 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3094 *fdp = arg.fd; 3095 3096 free(arg.buffer); 3097 3098 return (p); 3099 } 3100 3101 3102 /* 3103 * Finds the library with the given name using the directory descriptors 3104 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3105 * 3106 * Returns a freshly-opened close-on-exec file descriptor for the library, 3107 * or -1 if the library cannot be found. 3108 */ 3109 static char * 3110 search_library_pathfds(const char *name, const char *path, int *fdp) 3111 { 3112 char *envcopy, *fdstr, *found, *last_token; 3113 size_t len; 3114 int dirfd, fd; 3115 3116 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3117 3118 /* Don't load from user-specified libdirs into setuid binaries. */ 3119 if (!trust) 3120 return (NULL); 3121 3122 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3123 if (path == NULL) 3124 return (NULL); 3125 3126 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3127 if (name[0] == '/') { 3128 dbg("Absolute path (%s) passed to %s", name, __func__); 3129 return (NULL); 3130 } 3131 3132 /* 3133 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3134 * copy of the path, as strtok_r rewrites separator tokens 3135 * with '\0'. 3136 */ 3137 found = NULL; 3138 envcopy = xstrdup(path); 3139 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3140 fdstr = strtok_r(NULL, ":", &last_token)) { 3141 dirfd = parse_integer(fdstr); 3142 if (dirfd < 0) { 3143 _rtld_error("failed to parse directory FD: '%s'", 3144 fdstr); 3145 break; 3146 } 3147 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3148 if (fd >= 0) { 3149 *fdp = fd; 3150 len = strlen(fdstr) + strlen(name) + 3; 3151 found = xmalloc(len); 3152 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3153 _rtld_error("error generating '%d/%s'", 3154 dirfd, name); 3155 rtld_die(); 3156 } 3157 dbg("open('%s') => %d", found, fd); 3158 break; 3159 } 3160 } 3161 free(envcopy); 3162 3163 return (found); 3164 } 3165 3166 3167 int 3168 dlclose(void *handle) 3169 { 3170 RtldLockState lockstate; 3171 int error; 3172 3173 wlock_acquire(rtld_bind_lock, &lockstate); 3174 error = dlclose_locked(handle, &lockstate); 3175 lock_release(rtld_bind_lock, &lockstate); 3176 return (error); 3177 } 3178 3179 static int 3180 dlclose_locked(void *handle, RtldLockState *lockstate) 3181 { 3182 Obj_Entry *root; 3183 3184 root = dlcheck(handle); 3185 if (root == NULL) 3186 return -1; 3187 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3188 root->path); 3189 3190 /* Unreference the object and its dependencies. */ 3191 root->dl_refcount--; 3192 3193 if (root->refcount == 1) { 3194 /* 3195 * The object will be no longer referenced, so we must unload it. 3196 * First, call the fini functions. 3197 */ 3198 objlist_call_fini(&list_fini, root, lockstate); 3199 3200 unref_dag(root); 3201 3202 /* Finish cleaning up the newly-unreferenced objects. */ 3203 GDB_STATE(RT_DELETE,&root->linkmap); 3204 unload_object(root, lockstate); 3205 GDB_STATE(RT_CONSISTENT,NULL); 3206 } else 3207 unref_dag(root); 3208 3209 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3210 return 0; 3211 } 3212 3213 char * 3214 dlerror(void) 3215 { 3216 char *msg = error_message; 3217 error_message = NULL; 3218 return msg; 3219 } 3220 3221 /* 3222 * This function is deprecated and has no effect. 3223 */ 3224 void 3225 dllockinit(void *context, 3226 void *(*_lock_create)(void *context) __unused, 3227 void (*_rlock_acquire)(void *lock) __unused, 3228 void (*_wlock_acquire)(void *lock) __unused, 3229 void (*_lock_release)(void *lock) __unused, 3230 void (*_lock_destroy)(void *lock) __unused, 3231 void (*context_destroy)(void *context)) 3232 { 3233 static void *cur_context; 3234 static void (*cur_context_destroy)(void *); 3235 3236 /* Just destroy the context from the previous call, if necessary. */ 3237 if (cur_context_destroy != NULL) 3238 cur_context_destroy(cur_context); 3239 cur_context = context; 3240 cur_context_destroy = context_destroy; 3241 } 3242 3243 void * 3244 dlopen(const char *name, int mode) 3245 { 3246 3247 return (rtld_dlopen(name, -1, mode)); 3248 } 3249 3250 void * 3251 fdlopen(int fd, int mode) 3252 { 3253 3254 return (rtld_dlopen(NULL, fd, mode)); 3255 } 3256 3257 static void * 3258 rtld_dlopen(const char *name, int fd, int mode) 3259 { 3260 RtldLockState lockstate; 3261 int lo_flags; 3262 3263 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3264 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3265 if (ld_tracing != NULL) { 3266 rlock_acquire(rtld_bind_lock, &lockstate); 3267 if (sigsetjmp(lockstate.env, 0) != 0) 3268 lock_upgrade(rtld_bind_lock, &lockstate); 3269 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3270 lock_release(rtld_bind_lock, &lockstate); 3271 } 3272 lo_flags = RTLD_LO_DLOPEN; 3273 if (mode & RTLD_NODELETE) 3274 lo_flags |= RTLD_LO_NODELETE; 3275 if (mode & RTLD_NOLOAD) 3276 lo_flags |= RTLD_LO_NOLOAD; 3277 if (ld_tracing != NULL) 3278 lo_flags |= RTLD_LO_TRACE; 3279 3280 return (dlopen_object(name, fd, obj_main, lo_flags, 3281 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3282 } 3283 3284 static void 3285 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3286 { 3287 3288 obj->dl_refcount--; 3289 unref_dag(obj); 3290 if (obj->refcount == 0) 3291 unload_object(obj, lockstate); 3292 } 3293 3294 static Obj_Entry * 3295 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3296 int mode, RtldLockState *lockstate) 3297 { 3298 Obj_Entry *old_obj_tail; 3299 Obj_Entry *obj; 3300 Objlist initlist; 3301 RtldLockState mlockstate; 3302 int result; 3303 3304 objlist_init(&initlist); 3305 3306 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3307 wlock_acquire(rtld_bind_lock, &mlockstate); 3308 lockstate = &mlockstate; 3309 } 3310 GDB_STATE(RT_ADD,NULL); 3311 3312 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3313 obj = NULL; 3314 if (name == NULL && fd == -1) { 3315 obj = obj_main; 3316 obj->refcount++; 3317 } else { 3318 obj = load_object(name, fd, refobj, lo_flags); 3319 } 3320 3321 if (obj) { 3322 obj->dl_refcount++; 3323 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3324 objlist_push_tail(&list_global, obj); 3325 if (globallist_next(old_obj_tail) != NULL) { 3326 /* We loaded something new. */ 3327 assert(globallist_next(old_obj_tail) == obj); 3328 result = load_needed_objects(obj, 3329 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3330 init_dag(obj); 3331 ref_dag(obj); 3332 if (result != -1) 3333 result = rtld_verify_versions(&obj->dagmembers); 3334 if (result != -1 && ld_tracing) 3335 goto trace; 3336 if (result == -1 || relocate_object_dag(obj, 3337 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3338 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3339 lockstate) == -1) { 3340 dlopen_cleanup(obj, lockstate); 3341 obj = NULL; 3342 } else if (lo_flags & RTLD_LO_EARLY) { 3343 /* 3344 * Do not call the init functions for early loaded 3345 * filtees. The image is still not initialized enough 3346 * for them to work. 3347 * 3348 * Our object is found by the global object list and 3349 * will be ordered among all init calls done right 3350 * before transferring control to main. 3351 */ 3352 } else { 3353 /* Make list of init functions to call. */ 3354 initlist_add_objects(obj, obj, &initlist); 3355 } 3356 /* 3357 * Process all no_delete or global objects here, given 3358 * them own DAGs to prevent their dependencies from being 3359 * unloaded. This has to be done after we have loaded all 3360 * of the dependencies, so that we do not miss any. 3361 */ 3362 if (obj != NULL) 3363 process_z(obj); 3364 } else { 3365 /* 3366 * Bump the reference counts for objects on this DAG. If 3367 * this is the first dlopen() call for the object that was 3368 * already loaded as a dependency, initialize the dag 3369 * starting at it. 3370 */ 3371 init_dag(obj); 3372 ref_dag(obj); 3373 3374 if ((lo_flags & RTLD_LO_TRACE) != 0) 3375 goto trace; 3376 } 3377 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3378 obj->z_nodelete) && !obj->ref_nodel) { 3379 dbg("obj %s nodelete", obj->path); 3380 ref_dag(obj); 3381 obj->z_nodelete = obj->ref_nodel = true; 3382 } 3383 } 3384 3385 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3386 name); 3387 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3388 3389 if (!(lo_flags & RTLD_LO_EARLY)) { 3390 map_stacks_exec(lockstate); 3391 } 3392 3393 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3394 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3395 lockstate) == -1) { 3396 objlist_clear(&initlist); 3397 dlopen_cleanup(obj, lockstate); 3398 if (lockstate == &mlockstate) 3399 lock_release(rtld_bind_lock, lockstate); 3400 return (NULL); 3401 } 3402 3403 if (!(lo_flags & RTLD_LO_EARLY)) { 3404 /* Call the init functions. */ 3405 objlist_call_init(&initlist, lockstate); 3406 } 3407 objlist_clear(&initlist); 3408 if (lockstate == &mlockstate) 3409 lock_release(rtld_bind_lock, lockstate); 3410 return obj; 3411 trace: 3412 trace_loaded_objects(obj); 3413 if (lockstate == &mlockstate) 3414 lock_release(rtld_bind_lock, lockstate); 3415 exit(0); 3416 } 3417 3418 static void * 3419 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3420 int flags) 3421 { 3422 DoneList donelist; 3423 const Obj_Entry *obj, *defobj; 3424 const Elf_Sym *def; 3425 SymLook req; 3426 RtldLockState lockstate; 3427 tls_index ti; 3428 void *sym; 3429 int res; 3430 3431 def = NULL; 3432 defobj = NULL; 3433 symlook_init(&req, name); 3434 req.ventry = ve; 3435 req.flags = flags | SYMLOOK_IN_PLT; 3436 req.lockstate = &lockstate; 3437 3438 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3439 rlock_acquire(rtld_bind_lock, &lockstate); 3440 if (sigsetjmp(lockstate.env, 0) != 0) 3441 lock_upgrade(rtld_bind_lock, &lockstate); 3442 if (handle == NULL || handle == RTLD_NEXT || 3443 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3444 3445 if ((obj = obj_from_addr(retaddr)) == NULL) { 3446 _rtld_error("Cannot determine caller's shared object"); 3447 lock_release(rtld_bind_lock, &lockstate); 3448 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3449 return NULL; 3450 } 3451 if (handle == NULL) { /* Just the caller's shared object. */ 3452 res = symlook_obj(&req, obj); 3453 if (res == 0) { 3454 def = req.sym_out; 3455 defobj = req.defobj_out; 3456 } 3457 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3458 handle == RTLD_SELF) { /* ... caller included */ 3459 if (handle == RTLD_NEXT) 3460 obj = globallist_next(obj); 3461 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3462 if (obj->marker) 3463 continue; 3464 res = symlook_obj(&req, obj); 3465 if (res == 0) { 3466 if (def == NULL || 3467 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3468 def = req.sym_out; 3469 defobj = req.defobj_out; 3470 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3471 break; 3472 } 3473 } 3474 } 3475 /* 3476 * Search the dynamic linker itself, and possibly resolve the 3477 * symbol from there. This is how the application links to 3478 * dynamic linker services such as dlopen. 3479 */ 3480 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3481 res = symlook_obj(&req, &obj_rtld); 3482 if (res == 0) { 3483 def = req.sym_out; 3484 defobj = req.defobj_out; 3485 } 3486 } 3487 } else { 3488 assert(handle == RTLD_DEFAULT); 3489 res = symlook_default(&req, obj); 3490 if (res == 0) { 3491 defobj = req.defobj_out; 3492 def = req.sym_out; 3493 } 3494 } 3495 } else { 3496 if ((obj = dlcheck(handle)) == NULL) { 3497 lock_release(rtld_bind_lock, &lockstate); 3498 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3499 return NULL; 3500 } 3501 3502 donelist_init(&donelist); 3503 if (obj->mainprog) { 3504 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3505 res = symlook_global(&req, &donelist); 3506 if (res == 0) { 3507 def = req.sym_out; 3508 defobj = req.defobj_out; 3509 } 3510 /* 3511 * Search the dynamic linker itself, and possibly resolve the 3512 * symbol from there. This is how the application links to 3513 * dynamic linker services such as dlopen. 3514 */ 3515 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3516 res = symlook_obj(&req, &obj_rtld); 3517 if (res == 0) { 3518 def = req.sym_out; 3519 defobj = req.defobj_out; 3520 } 3521 } 3522 } 3523 else { 3524 /* Search the whole DAG rooted at the given object. */ 3525 res = symlook_list(&req, &obj->dagmembers, &donelist); 3526 if (res == 0) { 3527 def = req.sym_out; 3528 defobj = req.defobj_out; 3529 } 3530 } 3531 } 3532 3533 if (def != NULL) { 3534 lock_release(rtld_bind_lock, &lockstate); 3535 3536 /* 3537 * The value required by the caller is derived from the value 3538 * of the symbol. this is simply the relocated value of the 3539 * symbol. 3540 */ 3541 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3542 sym = make_function_pointer(def, defobj); 3543 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3544 sym = rtld_resolve_ifunc(defobj, def); 3545 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3546 ti.ti_module = defobj->tlsindex; 3547 ti.ti_offset = def->st_value; 3548 sym = __tls_get_addr(&ti); 3549 } else 3550 sym = defobj->relocbase + def->st_value; 3551 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3552 return (sym); 3553 } 3554 3555 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3556 ve != NULL ? ve->name : ""); 3557 lock_release(rtld_bind_lock, &lockstate); 3558 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3559 return NULL; 3560 } 3561 3562 void * 3563 dlsym(void *handle, const char *name) 3564 { 3565 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3566 SYMLOOK_DLSYM); 3567 } 3568 3569 dlfunc_t 3570 dlfunc(void *handle, const char *name) 3571 { 3572 union { 3573 void *d; 3574 dlfunc_t f; 3575 } rv; 3576 3577 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3578 SYMLOOK_DLSYM); 3579 return (rv.f); 3580 } 3581 3582 void * 3583 dlvsym(void *handle, const char *name, const char *version) 3584 { 3585 Ver_Entry ventry; 3586 3587 ventry.name = version; 3588 ventry.file = NULL; 3589 ventry.hash = elf_hash(version); 3590 ventry.flags= 0; 3591 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3592 SYMLOOK_DLSYM); 3593 } 3594 3595 int 3596 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3597 { 3598 const Obj_Entry *obj; 3599 RtldLockState lockstate; 3600 3601 rlock_acquire(rtld_bind_lock, &lockstate); 3602 obj = obj_from_addr(addr); 3603 if (obj == NULL) { 3604 _rtld_error("No shared object contains address"); 3605 lock_release(rtld_bind_lock, &lockstate); 3606 return (0); 3607 } 3608 rtld_fill_dl_phdr_info(obj, phdr_info); 3609 lock_release(rtld_bind_lock, &lockstate); 3610 return (1); 3611 } 3612 3613 int 3614 dladdr(const void *addr, Dl_info *info) 3615 { 3616 const Obj_Entry *obj; 3617 const Elf_Sym *def; 3618 void *symbol_addr; 3619 unsigned long symoffset; 3620 RtldLockState lockstate; 3621 3622 rlock_acquire(rtld_bind_lock, &lockstate); 3623 obj = obj_from_addr(addr); 3624 if (obj == NULL) { 3625 _rtld_error("No shared object contains address"); 3626 lock_release(rtld_bind_lock, &lockstate); 3627 return 0; 3628 } 3629 info->dli_fname = obj->path; 3630 info->dli_fbase = obj->mapbase; 3631 info->dli_saddr = (void *)0; 3632 info->dli_sname = NULL; 3633 3634 /* 3635 * Walk the symbol list looking for the symbol whose address is 3636 * closest to the address sent in. 3637 */ 3638 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3639 def = obj->symtab + symoffset; 3640 3641 /* 3642 * For skip the symbol if st_shndx is either SHN_UNDEF or 3643 * SHN_COMMON. 3644 */ 3645 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3646 continue; 3647 3648 /* 3649 * If the symbol is greater than the specified address, or if it 3650 * is further away from addr than the current nearest symbol, 3651 * then reject it. 3652 */ 3653 symbol_addr = obj->relocbase + def->st_value; 3654 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3655 continue; 3656 3657 /* Update our idea of the nearest symbol. */ 3658 info->dli_sname = obj->strtab + def->st_name; 3659 info->dli_saddr = symbol_addr; 3660 3661 /* Exact match? */ 3662 if (info->dli_saddr == addr) 3663 break; 3664 } 3665 lock_release(rtld_bind_lock, &lockstate); 3666 return 1; 3667 } 3668 3669 int 3670 dlinfo(void *handle, int request, void *p) 3671 { 3672 const Obj_Entry *obj; 3673 RtldLockState lockstate; 3674 int error; 3675 3676 rlock_acquire(rtld_bind_lock, &lockstate); 3677 3678 if (handle == NULL || handle == RTLD_SELF) { 3679 void *retaddr; 3680 3681 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3682 if ((obj = obj_from_addr(retaddr)) == NULL) 3683 _rtld_error("Cannot determine caller's shared object"); 3684 } else 3685 obj = dlcheck(handle); 3686 3687 if (obj == NULL) { 3688 lock_release(rtld_bind_lock, &lockstate); 3689 return (-1); 3690 } 3691 3692 error = 0; 3693 switch (request) { 3694 case RTLD_DI_LINKMAP: 3695 *((struct link_map const **)p) = &obj->linkmap; 3696 break; 3697 case RTLD_DI_ORIGIN: 3698 error = rtld_dirname(obj->path, p); 3699 break; 3700 3701 case RTLD_DI_SERINFOSIZE: 3702 case RTLD_DI_SERINFO: 3703 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3704 break; 3705 3706 default: 3707 _rtld_error("Invalid request %d passed to dlinfo()", request); 3708 error = -1; 3709 } 3710 3711 lock_release(rtld_bind_lock, &lockstate); 3712 3713 return (error); 3714 } 3715 3716 static void 3717 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3718 { 3719 3720 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3721 phdr_info->dlpi_name = obj->path; 3722 phdr_info->dlpi_phdr = obj->phdr; 3723 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3724 phdr_info->dlpi_tls_modid = obj->tlsindex; 3725 phdr_info->dlpi_tls_data = obj->tlsinit; 3726 phdr_info->dlpi_adds = obj_loads; 3727 phdr_info->dlpi_subs = obj_loads - obj_count; 3728 } 3729 3730 int 3731 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3732 { 3733 struct dl_phdr_info phdr_info; 3734 Obj_Entry *obj, marker; 3735 RtldLockState bind_lockstate, phdr_lockstate; 3736 int error; 3737 3738 init_marker(&marker); 3739 error = 0; 3740 3741 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3742 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3743 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3744 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3745 rtld_fill_dl_phdr_info(obj, &phdr_info); 3746 hold_object(obj); 3747 lock_release(rtld_bind_lock, &bind_lockstate); 3748 3749 error = callback(&phdr_info, sizeof phdr_info, param); 3750 3751 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3752 unhold_object(obj); 3753 obj = globallist_next(&marker); 3754 TAILQ_REMOVE(&obj_list, &marker, next); 3755 if (error != 0) { 3756 lock_release(rtld_bind_lock, &bind_lockstate); 3757 lock_release(rtld_phdr_lock, &phdr_lockstate); 3758 return (error); 3759 } 3760 } 3761 3762 if (error == 0) { 3763 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3764 lock_release(rtld_bind_lock, &bind_lockstate); 3765 error = callback(&phdr_info, sizeof(phdr_info), param); 3766 } 3767 lock_release(rtld_phdr_lock, &phdr_lockstate); 3768 return (error); 3769 } 3770 3771 static void * 3772 fill_search_info(const char *dir, size_t dirlen, void *param) 3773 { 3774 struct fill_search_info_args *arg; 3775 3776 arg = param; 3777 3778 if (arg->request == RTLD_DI_SERINFOSIZE) { 3779 arg->serinfo->dls_cnt ++; 3780 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3781 } else { 3782 struct dl_serpath *s_entry; 3783 3784 s_entry = arg->serpath; 3785 s_entry->dls_name = arg->strspace; 3786 s_entry->dls_flags = arg->flags; 3787 3788 strncpy(arg->strspace, dir, dirlen); 3789 arg->strspace[dirlen] = '\0'; 3790 3791 arg->strspace += dirlen + 1; 3792 arg->serpath++; 3793 } 3794 3795 return (NULL); 3796 } 3797 3798 static int 3799 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3800 { 3801 struct dl_serinfo _info; 3802 struct fill_search_info_args args; 3803 3804 args.request = RTLD_DI_SERINFOSIZE; 3805 args.serinfo = &_info; 3806 3807 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3808 _info.dls_cnt = 0; 3809 3810 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3811 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3812 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3813 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3814 if (!obj->z_nodeflib) 3815 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3816 3817 3818 if (request == RTLD_DI_SERINFOSIZE) { 3819 info->dls_size = _info.dls_size; 3820 info->dls_cnt = _info.dls_cnt; 3821 return (0); 3822 } 3823 3824 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3825 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3826 return (-1); 3827 } 3828 3829 args.request = RTLD_DI_SERINFO; 3830 args.serinfo = info; 3831 args.serpath = &info->dls_serpath[0]; 3832 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3833 3834 args.flags = LA_SER_RUNPATH; 3835 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3836 return (-1); 3837 3838 args.flags = LA_SER_LIBPATH; 3839 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3840 return (-1); 3841 3842 args.flags = LA_SER_RUNPATH; 3843 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3844 return (-1); 3845 3846 args.flags = LA_SER_CONFIG; 3847 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3848 != NULL) 3849 return (-1); 3850 3851 args.flags = LA_SER_DEFAULT; 3852 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3853 fill_search_info, NULL, &args) != NULL) 3854 return (-1); 3855 return (0); 3856 } 3857 3858 static int 3859 rtld_dirname(const char *path, char *bname) 3860 { 3861 const char *endp; 3862 3863 /* Empty or NULL string gets treated as "." */ 3864 if (path == NULL || *path == '\0') { 3865 bname[0] = '.'; 3866 bname[1] = '\0'; 3867 return (0); 3868 } 3869 3870 /* Strip trailing slashes */ 3871 endp = path + strlen(path) - 1; 3872 while (endp > path && *endp == '/') 3873 endp--; 3874 3875 /* Find the start of the dir */ 3876 while (endp > path && *endp != '/') 3877 endp--; 3878 3879 /* Either the dir is "/" or there are no slashes */ 3880 if (endp == path) { 3881 bname[0] = *endp == '/' ? '/' : '.'; 3882 bname[1] = '\0'; 3883 return (0); 3884 } else { 3885 do { 3886 endp--; 3887 } while (endp > path && *endp == '/'); 3888 } 3889 3890 if (endp - path + 2 > PATH_MAX) 3891 { 3892 _rtld_error("Filename is too long: %s", path); 3893 return(-1); 3894 } 3895 3896 strncpy(bname, path, endp - path + 1); 3897 bname[endp - path + 1] = '\0'; 3898 return (0); 3899 } 3900 3901 static int 3902 rtld_dirname_abs(const char *path, char *base) 3903 { 3904 char *last; 3905 3906 if (realpath(path, base) == NULL) 3907 return (-1); 3908 dbg("%s -> %s", path, base); 3909 last = strrchr(base, '/'); 3910 if (last == NULL) 3911 return (-1); 3912 if (last != base) 3913 *last = '\0'; 3914 return (0); 3915 } 3916 3917 static void 3918 linkmap_add(Obj_Entry *obj) 3919 { 3920 struct link_map *l = &obj->linkmap; 3921 struct link_map *prev; 3922 3923 obj->linkmap.l_name = obj->path; 3924 obj->linkmap.l_addr = obj->mapbase; 3925 obj->linkmap.l_ld = obj->dynamic; 3926 #ifdef __mips__ 3927 /* GDB needs load offset on MIPS to use the symbols */ 3928 obj->linkmap.l_offs = obj->relocbase; 3929 #endif 3930 3931 if (r_debug.r_map == NULL) { 3932 r_debug.r_map = l; 3933 return; 3934 } 3935 3936 /* 3937 * Scan to the end of the list, but not past the entry for the 3938 * dynamic linker, which we want to keep at the very end. 3939 */ 3940 for (prev = r_debug.r_map; 3941 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3942 prev = prev->l_next) 3943 ; 3944 3945 /* Link in the new entry. */ 3946 l->l_prev = prev; 3947 l->l_next = prev->l_next; 3948 if (l->l_next != NULL) 3949 l->l_next->l_prev = l; 3950 prev->l_next = l; 3951 } 3952 3953 static void 3954 linkmap_delete(Obj_Entry *obj) 3955 { 3956 struct link_map *l = &obj->linkmap; 3957 3958 if (l->l_prev == NULL) { 3959 if ((r_debug.r_map = l->l_next) != NULL) 3960 l->l_next->l_prev = NULL; 3961 return; 3962 } 3963 3964 if ((l->l_prev->l_next = l->l_next) != NULL) 3965 l->l_next->l_prev = l->l_prev; 3966 } 3967 3968 /* 3969 * Function for the debugger to set a breakpoint on to gain control. 3970 * 3971 * The two parameters allow the debugger to easily find and determine 3972 * what the runtime loader is doing and to whom it is doing it. 3973 * 3974 * When the loadhook trap is hit (r_debug_state, set at program 3975 * initialization), the arguments can be found on the stack: 3976 * 3977 * +8 struct link_map *m 3978 * +4 struct r_debug *rd 3979 * +0 RetAddr 3980 */ 3981 void 3982 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3983 { 3984 /* 3985 * The following is a hack to force the compiler to emit calls to 3986 * this function, even when optimizing. If the function is empty, 3987 * the compiler is not obliged to emit any code for calls to it, 3988 * even when marked __noinline. However, gdb depends on those 3989 * calls being made. 3990 */ 3991 __compiler_membar(); 3992 } 3993 3994 /* 3995 * A function called after init routines have completed. This can be used to 3996 * break before a program's entry routine is called, and can be used when 3997 * main is not available in the symbol table. 3998 */ 3999 void 4000 _r_debug_postinit(struct link_map *m __unused) 4001 { 4002 4003 /* See r_debug_state(). */ 4004 __compiler_membar(); 4005 } 4006 4007 static void 4008 release_object(Obj_Entry *obj) 4009 { 4010 4011 if (obj->holdcount > 0) { 4012 obj->unholdfree = true; 4013 return; 4014 } 4015 munmap(obj->mapbase, obj->mapsize); 4016 linkmap_delete(obj); 4017 obj_free(obj); 4018 } 4019 4020 /* 4021 * Get address of the pointer variable in the main program. 4022 * Prefer non-weak symbol over the weak one. 4023 */ 4024 static const void ** 4025 get_program_var_addr(const char *name, RtldLockState *lockstate) 4026 { 4027 SymLook req; 4028 DoneList donelist; 4029 4030 symlook_init(&req, name); 4031 req.lockstate = lockstate; 4032 donelist_init(&donelist); 4033 if (symlook_global(&req, &donelist) != 0) 4034 return (NULL); 4035 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4036 return ((const void **)make_function_pointer(req.sym_out, 4037 req.defobj_out)); 4038 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4039 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4040 else 4041 return ((const void **)(req.defobj_out->relocbase + 4042 req.sym_out->st_value)); 4043 } 4044 4045 /* 4046 * Set a pointer variable in the main program to the given value. This 4047 * is used to set key variables such as "environ" before any of the 4048 * init functions are called. 4049 */ 4050 static void 4051 set_program_var(const char *name, const void *value) 4052 { 4053 const void **addr; 4054 4055 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4056 dbg("\"%s\": *%p <-- %p", name, addr, value); 4057 *addr = value; 4058 } 4059 } 4060 4061 /* 4062 * Search the global objects, including dependencies and main object, 4063 * for the given symbol. 4064 */ 4065 static int 4066 symlook_global(SymLook *req, DoneList *donelist) 4067 { 4068 SymLook req1; 4069 const Objlist_Entry *elm; 4070 int res; 4071 4072 symlook_init_from_req(&req1, req); 4073 4074 /* Search all objects loaded at program start up. */ 4075 if (req->defobj_out == NULL || 4076 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4077 res = symlook_list(&req1, &list_main, donelist); 4078 if (res == 0 && (req->defobj_out == NULL || 4079 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4080 req->sym_out = req1.sym_out; 4081 req->defobj_out = req1.defobj_out; 4082 assert(req->defobj_out != NULL); 4083 } 4084 } 4085 4086 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4087 STAILQ_FOREACH(elm, &list_global, link) { 4088 if (req->defobj_out != NULL && 4089 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4090 break; 4091 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4092 if (res == 0 && (req->defobj_out == NULL || 4093 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4094 req->sym_out = req1.sym_out; 4095 req->defobj_out = req1.defobj_out; 4096 assert(req->defobj_out != NULL); 4097 } 4098 } 4099 4100 return (req->sym_out != NULL ? 0 : ESRCH); 4101 } 4102 4103 /* 4104 * Given a symbol name in a referencing object, find the corresponding 4105 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4106 * no definition was found. Returns a pointer to the Obj_Entry of the 4107 * defining object via the reference parameter DEFOBJ_OUT. 4108 */ 4109 static int 4110 symlook_default(SymLook *req, const Obj_Entry *refobj) 4111 { 4112 DoneList donelist; 4113 const Objlist_Entry *elm; 4114 SymLook req1; 4115 int res; 4116 4117 donelist_init(&donelist); 4118 symlook_init_from_req(&req1, req); 4119 4120 /* 4121 * Look first in the referencing object if linked symbolically, 4122 * and similarly handle protected symbols. 4123 */ 4124 res = symlook_obj(&req1, refobj); 4125 if (res == 0 && (refobj->symbolic || 4126 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4127 req->sym_out = req1.sym_out; 4128 req->defobj_out = req1.defobj_out; 4129 assert(req->defobj_out != NULL); 4130 } 4131 if (refobj->symbolic || req->defobj_out != NULL) 4132 donelist_check(&donelist, refobj); 4133 4134 symlook_global(req, &donelist); 4135 4136 /* Search all dlopened DAGs containing the referencing object. */ 4137 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4138 if (req->sym_out != NULL && 4139 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4140 break; 4141 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4142 if (res == 0 && (req->sym_out == NULL || 4143 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4144 req->sym_out = req1.sym_out; 4145 req->defobj_out = req1.defobj_out; 4146 assert(req->defobj_out != NULL); 4147 } 4148 } 4149 4150 /* 4151 * Search the dynamic linker itself, and possibly resolve the 4152 * symbol from there. This is how the application links to 4153 * dynamic linker services such as dlopen. 4154 */ 4155 if (req->sym_out == NULL || 4156 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4157 res = symlook_obj(&req1, &obj_rtld); 4158 if (res == 0) { 4159 req->sym_out = req1.sym_out; 4160 req->defobj_out = req1.defobj_out; 4161 assert(req->defobj_out != NULL); 4162 } 4163 } 4164 4165 return (req->sym_out != NULL ? 0 : ESRCH); 4166 } 4167 4168 static int 4169 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4170 { 4171 const Elf_Sym *def; 4172 const Obj_Entry *defobj; 4173 const Objlist_Entry *elm; 4174 SymLook req1; 4175 int res; 4176 4177 def = NULL; 4178 defobj = NULL; 4179 STAILQ_FOREACH(elm, objlist, link) { 4180 if (donelist_check(dlp, elm->obj)) 4181 continue; 4182 symlook_init_from_req(&req1, req); 4183 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4184 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4185 def = req1.sym_out; 4186 defobj = req1.defobj_out; 4187 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4188 break; 4189 } 4190 } 4191 } 4192 if (def != NULL) { 4193 req->sym_out = def; 4194 req->defobj_out = defobj; 4195 return (0); 4196 } 4197 return (ESRCH); 4198 } 4199 4200 /* 4201 * Search the chain of DAGS cointed to by the given Needed_Entry 4202 * for a symbol of the given name. Each DAG is scanned completely 4203 * before advancing to the next one. Returns a pointer to the symbol, 4204 * or NULL if no definition was found. 4205 */ 4206 static int 4207 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4208 { 4209 const Elf_Sym *def; 4210 const Needed_Entry *n; 4211 const Obj_Entry *defobj; 4212 SymLook req1; 4213 int res; 4214 4215 def = NULL; 4216 defobj = NULL; 4217 symlook_init_from_req(&req1, req); 4218 for (n = needed; n != NULL; n = n->next) { 4219 if (n->obj == NULL || 4220 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4221 continue; 4222 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4223 def = req1.sym_out; 4224 defobj = req1.defobj_out; 4225 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4226 break; 4227 } 4228 } 4229 if (def != NULL) { 4230 req->sym_out = def; 4231 req->defobj_out = defobj; 4232 return (0); 4233 } 4234 return (ESRCH); 4235 } 4236 4237 /* 4238 * Search the symbol table of a single shared object for a symbol of 4239 * the given name and version, if requested. Returns a pointer to the 4240 * symbol, or NULL if no definition was found. If the object is 4241 * filter, return filtered symbol from filtee. 4242 * 4243 * The symbol's hash value is passed in for efficiency reasons; that 4244 * eliminates many recomputations of the hash value. 4245 */ 4246 int 4247 symlook_obj(SymLook *req, const Obj_Entry *obj) 4248 { 4249 DoneList donelist; 4250 SymLook req1; 4251 int flags, res, mres; 4252 4253 /* 4254 * If there is at least one valid hash at this point, we prefer to 4255 * use the faster GNU version if available. 4256 */ 4257 if (obj->valid_hash_gnu) 4258 mres = symlook_obj1_gnu(req, obj); 4259 else if (obj->valid_hash_sysv) 4260 mres = symlook_obj1_sysv(req, obj); 4261 else 4262 return (EINVAL); 4263 4264 if (mres == 0) { 4265 if (obj->needed_filtees != NULL) { 4266 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4267 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4268 donelist_init(&donelist); 4269 symlook_init_from_req(&req1, req); 4270 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4271 if (res == 0) { 4272 req->sym_out = req1.sym_out; 4273 req->defobj_out = req1.defobj_out; 4274 } 4275 return (res); 4276 } 4277 if (obj->needed_aux_filtees != NULL) { 4278 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4279 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4280 donelist_init(&donelist); 4281 symlook_init_from_req(&req1, req); 4282 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4283 if (res == 0) { 4284 req->sym_out = req1.sym_out; 4285 req->defobj_out = req1.defobj_out; 4286 return (res); 4287 } 4288 } 4289 } 4290 return (mres); 4291 } 4292 4293 /* Symbol match routine common to both hash functions */ 4294 static bool 4295 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4296 const unsigned long symnum) 4297 { 4298 Elf_Versym verndx; 4299 const Elf_Sym *symp; 4300 const char *strp; 4301 4302 symp = obj->symtab + symnum; 4303 strp = obj->strtab + symp->st_name; 4304 4305 switch (ELF_ST_TYPE(symp->st_info)) { 4306 case STT_FUNC: 4307 case STT_NOTYPE: 4308 case STT_OBJECT: 4309 case STT_COMMON: 4310 case STT_GNU_IFUNC: 4311 if (symp->st_value == 0) 4312 return (false); 4313 /* fallthrough */ 4314 case STT_TLS: 4315 if (symp->st_shndx != SHN_UNDEF) 4316 break; 4317 #ifndef __mips__ 4318 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4319 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4320 break; 4321 #endif 4322 /* fallthrough */ 4323 default: 4324 return (false); 4325 } 4326 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4327 return (false); 4328 4329 if (req->ventry == NULL) { 4330 if (obj->versyms != NULL) { 4331 verndx = VER_NDX(obj->versyms[symnum]); 4332 if (verndx > obj->vernum) { 4333 _rtld_error( 4334 "%s: symbol %s references wrong version %d", 4335 obj->path, obj->strtab + symnum, verndx); 4336 return (false); 4337 } 4338 /* 4339 * If we are not called from dlsym (i.e. this 4340 * is a normal relocation from unversioned 4341 * binary), accept the symbol immediately if 4342 * it happens to have first version after this 4343 * shared object became versioned. Otherwise, 4344 * if symbol is versioned and not hidden, 4345 * remember it. If it is the only symbol with 4346 * this name exported by the shared object, it 4347 * will be returned as a match by the calling 4348 * function. If symbol is global (verndx < 2) 4349 * accept it unconditionally. 4350 */ 4351 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4352 verndx == VER_NDX_GIVEN) { 4353 result->sym_out = symp; 4354 return (true); 4355 } 4356 else if (verndx >= VER_NDX_GIVEN) { 4357 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4358 == 0) { 4359 if (result->vsymp == NULL) 4360 result->vsymp = symp; 4361 result->vcount++; 4362 } 4363 return (false); 4364 } 4365 } 4366 result->sym_out = symp; 4367 return (true); 4368 } 4369 if (obj->versyms == NULL) { 4370 if (object_match_name(obj, req->ventry->name)) { 4371 _rtld_error("%s: object %s should provide version %s " 4372 "for symbol %s", obj_rtld.path, obj->path, 4373 req->ventry->name, obj->strtab + symnum); 4374 return (false); 4375 } 4376 } else { 4377 verndx = VER_NDX(obj->versyms[symnum]); 4378 if (verndx > obj->vernum) { 4379 _rtld_error("%s: symbol %s references wrong version %d", 4380 obj->path, obj->strtab + symnum, verndx); 4381 return (false); 4382 } 4383 if (obj->vertab[verndx].hash != req->ventry->hash || 4384 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4385 /* 4386 * Version does not match. Look if this is a 4387 * global symbol and if it is not hidden. If 4388 * global symbol (verndx < 2) is available, 4389 * use it. Do not return symbol if we are 4390 * called by dlvsym, because dlvsym looks for 4391 * a specific version and default one is not 4392 * what dlvsym wants. 4393 */ 4394 if ((req->flags & SYMLOOK_DLSYM) || 4395 (verndx >= VER_NDX_GIVEN) || 4396 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4397 return (false); 4398 } 4399 } 4400 result->sym_out = symp; 4401 return (true); 4402 } 4403 4404 /* 4405 * Search for symbol using SysV hash function. 4406 * obj->buckets is known not to be NULL at this point; the test for this was 4407 * performed with the obj->valid_hash_sysv assignment. 4408 */ 4409 static int 4410 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4411 { 4412 unsigned long symnum; 4413 Sym_Match_Result matchres; 4414 4415 matchres.sym_out = NULL; 4416 matchres.vsymp = NULL; 4417 matchres.vcount = 0; 4418 4419 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4420 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4421 if (symnum >= obj->nchains) 4422 return (ESRCH); /* Bad object */ 4423 4424 if (matched_symbol(req, obj, &matchres, symnum)) { 4425 req->sym_out = matchres.sym_out; 4426 req->defobj_out = obj; 4427 return (0); 4428 } 4429 } 4430 if (matchres.vcount == 1) { 4431 req->sym_out = matchres.vsymp; 4432 req->defobj_out = obj; 4433 return (0); 4434 } 4435 return (ESRCH); 4436 } 4437 4438 /* Search for symbol using GNU hash function */ 4439 static int 4440 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4441 { 4442 Elf_Addr bloom_word; 4443 const Elf32_Word *hashval; 4444 Elf32_Word bucket; 4445 Sym_Match_Result matchres; 4446 unsigned int h1, h2; 4447 unsigned long symnum; 4448 4449 matchres.sym_out = NULL; 4450 matchres.vsymp = NULL; 4451 matchres.vcount = 0; 4452 4453 /* Pick right bitmask word from Bloom filter array */ 4454 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4455 obj->maskwords_bm_gnu]; 4456 4457 /* Calculate modulus word size of gnu hash and its derivative */ 4458 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4459 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4460 4461 /* Filter out the "definitely not in set" queries */ 4462 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4463 return (ESRCH); 4464 4465 /* Locate hash chain and corresponding value element*/ 4466 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4467 if (bucket == 0) 4468 return (ESRCH); 4469 hashval = &obj->chain_zero_gnu[bucket]; 4470 do { 4471 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4472 symnum = hashval - obj->chain_zero_gnu; 4473 if (matched_symbol(req, obj, &matchres, symnum)) { 4474 req->sym_out = matchres.sym_out; 4475 req->defobj_out = obj; 4476 return (0); 4477 } 4478 } 4479 } while ((*hashval++ & 1) == 0); 4480 if (matchres.vcount == 1) { 4481 req->sym_out = matchres.vsymp; 4482 req->defobj_out = obj; 4483 return (0); 4484 } 4485 return (ESRCH); 4486 } 4487 4488 static void 4489 trace_loaded_objects(Obj_Entry *obj) 4490 { 4491 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4492 int c; 4493 4494 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4495 main_local = ""; 4496 4497 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4498 fmt1 = "\t%o => %p (%x)\n"; 4499 4500 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4501 fmt2 = "\t%o (%x)\n"; 4502 4503 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4504 4505 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4506 Needed_Entry *needed; 4507 const char *name, *path; 4508 bool is_lib; 4509 4510 if (obj->marker) 4511 continue; 4512 if (list_containers && obj->needed != NULL) 4513 rtld_printf("%s:\n", obj->path); 4514 for (needed = obj->needed; needed; needed = needed->next) { 4515 if (needed->obj != NULL) { 4516 if (needed->obj->traced && !list_containers) 4517 continue; 4518 needed->obj->traced = true; 4519 path = needed->obj->path; 4520 } else 4521 path = "not found"; 4522 4523 name = obj->strtab + needed->name; 4524 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4525 4526 fmt = is_lib ? fmt1 : fmt2; 4527 while ((c = *fmt++) != '\0') { 4528 switch (c) { 4529 default: 4530 rtld_putchar(c); 4531 continue; 4532 case '\\': 4533 switch (c = *fmt) { 4534 case '\0': 4535 continue; 4536 case 'n': 4537 rtld_putchar('\n'); 4538 break; 4539 case 't': 4540 rtld_putchar('\t'); 4541 break; 4542 } 4543 break; 4544 case '%': 4545 switch (c = *fmt) { 4546 case '\0': 4547 continue; 4548 case '%': 4549 default: 4550 rtld_putchar(c); 4551 break; 4552 case 'A': 4553 rtld_putstr(main_local); 4554 break; 4555 case 'a': 4556 rtld_putstr(obj_main->path); 4557 break; 4558 case 'o': 4559 rtld_putstr(name); 4560 break; 4561 #if 0 4562 case 'm': 4563 rtld_printf("%d", sodp->sod_major); 4564 break; 4565 case 'n': 4566 rtld_printf("%d", sodp->sod_minor); 4567 break; 4568 #endif 4569 case 'p': 4570 rtld_putstr(path); 4571 break; 4572 case 'x': 4573 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4574 0); 4575 break; 4576 } 4577 break; 4578 } 4579 ++fmt; 4580 } 4581 } 4582 } 4583 } 4584 4585 /* 4586 * Unload a dlopened object and its dependencies from memory and from 4587 * our data structures. It is assumed that the DAG rooted in the 4588 * object has already been unreferenced, and that the object has a 4589 * reference count of 0. 4590 */ 4591 static void 4592 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4593 { 4594 Obj_Entry marker, *obj, *next; 4595 4596 assert(root->refcount == 0); 4597 4598 /* 4599 * Pass over the DAG removing unreferenced objects from 4600 * appropriate lists. 4601 */ 4602 unlink_object(root); 4603 4604 /* Unmap all objects that are no longer referenced. */ 4605 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4606 next = TAILQ_NEXT(obj, next); 4607 if (obj->marker || obj->refcount != 0) 4608 continue; 4609 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4610 obj->mapsize, 0, obj->path); 4611 dbg("unloading \"%s\"", obj->path); 4612 /* 4613 * Unlink the object now to prevent new references from 4614 * being acquired while the bind lock is dropped in 4615 * recursive dlclose() invocations. 4616 */ 4617 TAILQ_REMOVE(&obj_list, obj, next); 4618 obj_count--; 4619 4620 if (obj->filtees_loaded) { 4621 if (next != NULL) { 4622 init_marker(&marker); 4623 TAILQ_INSERT_BEFORE(next, &marker, next); 4624 unload_filtees(obj, lockstate); 4625 next = TAILQ_NEXT(&marker, next); 4626 TAILQ_REMOVE(&obj_list, &marker, next); 4627 } else 4628 unload_filtees(obj, lockstate); 4629 } 4630 release_object(obj); 4631 } 4632 } 4633 4634 static void 4635 unlink_object(Obj_Entry *root) 4636 { 4637 Objlist_Entry *elm; 4638 4639 if (root->refcount == 0) { 4640 /* Remove the object from the RTLD_GLOBAL list. */ 4641 objlist_remove(&list_global, root); 4642 4643 /* Remove the object from all objects' DAG lists. */ 4644 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4645 objlist_remove(&elm->obj->dldags, root); 4646 if (elm->obj != root) 4647 unlink_object(elm->obj); 4648 } 4649 } 4650 } 4651 4652 static void 4653 ref_dag(Obj_Entry *root) 4654 { 4655 Objlist_Entry *elm; 4656 4657 assert(root->dag_inited); 4658 STAILQ_FOREACH(elm, &root->dagmembers, link) 4659 elm->obj->refcount++; 4660 } 4661 4662 static void 4663 unref_dag(Obj_Entry *root) 4664 { 4665 Objlist_Entry *elm; 4666 4667 assert(root->dag_inited); 4668 STAILQ_FOREACH(elm, &root->dagmembers, link) 4669 elm->obj->refcount--; 4670 } 4671 4672 /* 4673 * Common code for MD __tls_get_addr(). 4674 */ 4675 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4676 static void * 4677 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4678 { 4679 Elf_Addr *newdtv, *dtv; 4680 RtldLockState lockstate; 4681 int to_copy; 4682 4683 dtv = *dtvp; 4684 /* Check dtv generation in case new modules have arrived */ 4685 if (dtv[0] != tls_dtv_generation) { 4686 wlock_acquire(rtld_bind_lock, &lockstate); 4687 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4688 to_copy = dtv[1]; 4689 if (to_copy > tls_max_index) 4690 to_copy = tls_max_index; 4691 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4692 newdtv[0] = tls_dtv_generation; 4693 newdtv[1] = tls_max_index; 4694 free(dtv); 4695 lock_release(rtld_bind_lock, &lockstate); 4696 dtv = *dtvp = newdtv; 4697 } 4698 4699 /* Dynamically allocate module TLS if necessary */ 4700 if (dtv[index + 1] == 0) { 4701 /* Signal safe, wlock will block out signals. */ 4702 wlock_acquire(rtld_bind_lock, &lockstate); 4703 if (!dtv[index + 1]) 4704 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4705 lock_release(rtld_bind_lock, &lockstate); 4706 } 4707 return ((void *)(dtv[index + 1] + offset)); 4708 } 4709 4710 void * 4711 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4712 { 4713 Elf_Addr *dtv; 4714 4715 dtv = *dtvp; 4716 /* Check dtv generation in case new modules have arrived */ 4717 if (__predict_true(dtv[0] == tls_dtv_generation && 4718 dtv[index + 1] != 0)) 4719 return ((void *)(dtv[index + 1] + offset)); 4720 return (tls_get_addr_slow(dtvp, index, offset)); 4721 } 4722 4723 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4724 defined(__powerpc__) || defined(__riscv) 4725 4726 /* 4727 * Return pointer to allocated TLS block 4728 */ 4729 static void * 4730 get_tls_block_ptr(void *tcb, size_t tcbsize) 4731 { 4732 size_t extra_size, post_size, pre_size, tls_block_size; 4733 size_t tls_init_align; 4734 4735 tls_init_align = MAX(obj_main->tlsalign, 1); 4736 4737 /* Compute fragments sizes. */ 4738 extra_size = tcbsize - TLS_TCB_SIZE; 4739 post_size = calculate_tls_post_size(tls_init_align); 4740 tls_block_size = tcbsize + post_size; 4741 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4742 4743 return ((char *)tcb - pre_size - extra_size); 4744 } 4745 4746 /* 4747 * Allocate Static TLS using the Variant I method. 4748 * 4749 * For details on the layout, see lib/libc/gen/tls.c. 4750 * 4751 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4752 * it is based on tls_last_offset, and TLS offsets here are really TCB 4753 * offsets, whereas libc's tls_static_space is just the executable's static 4754 * TLS segment. 4755 */ 4756 void * 4757 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4758 { 4759 Obj_Entry *obj; 4760 char *tls_block; 4761 Elf_Addr *dtv, **tcb; 4762 Elf_Addr addr; 4763 Elf_Addr i; 4764 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4765 size_t tls_init_align; 4766 4767 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4768 return (oldtcb); 4769 4770 assert(tcbsize >= TLS_TCB_SIZE); 4771 maxalign = MAX(tcbalign, tls_static_max_align); 4772 tls_init_align = MAX(obj_main->tlsalign, 1); 4773 4774 /* Compute fragmets sizes. */ 4775 extra_size = tcbsize - TLS_TCB_SIZE; 4776 post_size = calculate_tls_post_size(tls_init_align); 4777 tls_block_size = tcbsize + post_size; 4778 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4779 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4780 4781 /* Allocate whole TLS block */ 4782 tls_block = malloc_aligned(tls_block_size, maxalign); 4783 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4784 4785 if (oldtcb != NULL) { 4786 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4787 tls_static_space); 4788 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4789 4790 /* Adjust the DTV. */ 4791 dtv = tcb[0]; 4792 for (i = 0; i < dtv[1]; i++) { 4793 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4794 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4795 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4796 } 4797 } 4798 } else { 4799 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4800 tcb[0] = dtv; 4801 dtv[0] = tls_dtv_generation; 4802 dtv[1] = tls_max_index; 4803 4804 for (obj = globallist_curr(objs); obj != NULL; 4805 obj = globallist_next(obj)) { 4806 if (obj->tlsoffset > 0) { 4807 addr = (Elf_Addr)tcb + obj->tlsoffset; 4808 if (obj->tlsinitsize > 0) 4809 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4810 if (obj->tlssize > obj->tlsinitsize) 4811 memset((void*)(addr + obj->tlsinitsize), 0, 4812 obj->tlssize - obj->tlsinitsize); 4813 dtv[obj->tlsindex + 1] = addr; 4814 } 4815 } 4816 } 4817 4818 return (tcb); 4819 } 4820 4821 void 4822 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4823 { 4824 Elf_Addr *dtv; 4825 Elf_Addr tlsstart, tlsend; 4826 size_t post_size; 4827 size_t dtvsize, i, tls_init_align; 4828 4829 assert(tcbsize >= TLS_TCB_SIZE); 4830 tls_init_align = MAX(obj_main->tlsalign, 1); 4831 4832 /* Compute fragments sizes. */ 4833 post_size = calculate_tls_post_size(tls_init_align); 4834 4835 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4836 tlsend = (Elf_Addr)tcb + tls_static_space; 4837 4838 dtv = *(Elf_Addr **)tcb; 4839 dtvsize = dtv[1]; 4840 for (i = 0; i < dtvsize; i++) { 4841 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4842 free((void*)dtv[i+2]); 4843 } 4844 } 4845 free(dtv); 4846 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4847 } 4848 4849 #endif 4850 4851 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4852 4853 /* 4854 * Allocate Static TLS using the Variant II method. 4855 */ 4856 void * 4857 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4858 { 4859 Obj_Entry *obj; 4860 size_t size, ralign; 4861 char *tls; 4862 Elf_Addr *dtv, *olddtv; 4863 Elf_Addr segbase, oldsegbase, addr; 4864 size_t i; 4865 4866 ralign = tcbalign; 4867 if (tls_static_max_align > ralign) 4868 ralign = tls_static_max_align; 4869 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4870 4871 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4872 tls = malloc_aligned(size, ralign); 4873 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4874 4875 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4876 ((Elf_Addr*)segbase)[0] = segbase; 4877 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4878 4879 dtv[0] = tls_dtv_generation; 4880 dtv[1] = tls_max_index; 4881 4882 if (oldtls) { 4883 /* 4884 * Copy the static TLS block over whole. 4885 */ 4886 oldsegbase = (Elf_Addr) oldtls; 4887 memcpy((void *)(segbase - tls_static_space), 4888 (const void *)(oldsegbase - tls_static_space), 4889 tls_static_space); 4890 4891 /* 4892 * If any dynamic TLS blocks have been created tls_get_addr(), 4893 * move them over. 4894 */ 4895 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4896 for (i = 0; i < olddtv[1]; i++) { 4897 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4898 dtv[i+2] = olddtv[i+2]; 4899 olddtv[i+2] = 0; 4900 } 4901 } 4902 4903 /* 4904 * We assume that this block was the one we created with 4905 * allocate_initial_tls(). 4906 */ 4907 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4908 } else { 4909 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4910 if (obj->marker || obj->tlsoffset == 0) 4911 continue; 4912 addr = segbase - obj->tlsoffset; 4913 memset((void*)(addr + obj->tlsinitsize), 4914 0, obj->tlssize - obj->tlsinitsize); 4915 if (obj->tlsinit) 4916 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4917 dtv[obj->tlsindex + 1] = addr; 4918 } 4919 } 4920 4921 return (void*) segbase; 4922 } 4923 4924 void 4925 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4926 { 4927 Elf_Addr* dtv; 4928 size_t size, ralign; 4929 int dtvsize, i; 4930 Elf_Addr tlsstart, tlsend; 4931 4932 /* 4933 * Figure out the size of the initial TLS block so that we can 4934 * find stuff which ___tls_get_addr() allocated dynamically. 4935 */ 4936 ralign = tcbalign; 4937 if (tls_static_max_align > ralign) 4938 ralign = tls_static_max_align; 4939 size = round(tls_static_space, ralign); 4940 4941 dtv = ((Elf_Addr**)tls)[1]; 4942 dtvsize = dtv[1]; 4943 tlsend = (Elf_Addr) tls; 4944 tlsstart = tlsend - size; 4945 for (i = 0; i < dtvsize; i++) { 4946 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4947 free_aligned((void *)dtv[i + 2]); 4948 } 4949 } 4950 4951 free_aligned((void *)tlsstart); 4952 free((void*) dtv); 4953 } 4954 4955 #endif 4956 4957 /* 4958 * Allocate TLS block for module with given index. 4959 */ 4960 void * 4961 allocate_module_tls(int index) 4962 { 4963 Obj_Entry* obj; 4964 char* p; 4965 4966 TAILQ_FOREACH(obj, &obj_list, next) { 4967 if (obj->marker) 4968 continue; 4969 if (obj->tlsindex == index) 4970 break; 4971 } 4972 if (!obj) { 4973 _rtld_error("Can't find module with TLS index %d", index); 4974 rtld_die(); 4975 } 4976 4977 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4978 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4979 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4980 4981 return p; 4982 } 4983 4984 bool 4985 allocate_tls_offset(Obj_Entry *obj) 4986 { 4987 size_t off; 4988 4989 if (obj->tls_done) 4990 return true; 4991 4992 if (obj->tlssize == 0) { 4993 obj->tls_done = true; 4994 return true; 4995 } 4996 4997 if (tls_last_offset == 0) 4998 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4999 else 5000 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5001 obj->tlssize, obj->tlsalign); 5002 5003 /* 5004 * If we have already fixed the size of the static TLS block, we 5005 * must stay within that size. When allocating the static TLS, we 5006 * leave a small amount of space spare to be used for dynamically 5007 * loading modules which use static TLS. 5008 */ 5009 if (tls_static_space != 0) { 5010 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5011 return false; 5012 } else if (obj->tlsalign > tls_static_max_align) { 5013 tls_static_max_align = obj->tlsalign; 5014 } 5015 5016 tls_last_offset = obj->tlsoffset = off; 5017 tls_last_size = obj->tlssize; 5018 obj->tls_done = true; 5019 5020 return true; 5021 } 5022 5023 void 5024 free_tls_offset(Obj_Entry *obj) 5025 { 5026 5027 /* 5028 * If we were the last thing to allocate out of the static TLS 5029 * block, we give our space back to the 'allocator'. This is a 5030 * simplistic workaround to allow libGL.so.1 to be loaded and 5031 * unloaded multiple times. 5032 */ 5033 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5034 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5035 tls_last_offset -= obj->tlssize; 5036 tls_last_size = 0; 5037 } 5038 } 5039 5040 void * 5041 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5042 { 5043 void *ret; 5044 RtldLockState lockstate; 5045 5046 wlock_acquire(rtld_bind_lock, &lockstate); 5047 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5048 tcbsize, tcbalign); 5049 lock_release(rtld_bind_lock, &lockstate); 5050 return (ret); 5051 } 5052 5053 void 5054 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5055 { 5056 RtldLockState lockstate; 5057 5058 wlock_acquire(rtld_bind_lock, &lockstate); 5059 free_tls(tcb, tcbsize, tcbalign); 5060 lock_release(rtld_bind_lock, &lockstate); 5061 } 5062 5063 static void 5064 object_add_name(Obj_Entry *obj, const char *name) 5065 { 5066 Name_Entry *entry; 5067 size_t len; 5068 5069 len = strlen(name); 5070 entry = malloc(sizeof(Name_Entry) + len); 5071 5072 if (entry != NULL) { 5073 strcpy(entry->name, name); 5074 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5075 } 5076 } 5077 5078 static int 5079 object_match_name(const Obj_Entry *obj, const char *name) 5080 { 5081 Name_Entry *entry; 5082 5083 STAILQ_FOREACH(entry, &obj->names, link) { 5084 if (strcmp(name, entry->name) == 0) 5085 return (1); 5086 } 5087 return (0); 5088 } 5089 5090 static Obj_Entry * 5091 locate_dependency(const Obj_Entry *obj, const char *name) 5092 { 5093 const Objlist_Entry *entry; 5094 const Needed_Entry *needed; 5095 5096 STAILQ_FOREACH(entry, &list_main, link) { 5097 if (object_match_name(entry->obj, name)) 5098 return entry->obj; 5099 } 5100 5101 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5102 if (strcmp(obj->strtab + needed->name, name) == 0 || 5103 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5104 /* 5105 * If there is DT_NEEDED for the name we are looking for, 5106 * we are all set. Note that object might not be found if 5107 * dependency was not loaded yet, so the function can 5108 * return NULL here. This is expected and handled 5109 * properly by the caller. 5110 */ 5111 return (needed->obj); 5112 } 5113 } 5114 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5115 obj->path, name); 5116 rtld_die(); 5117 } 5118 5119 static int 5120 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5121 const Elf_Vernaux *vna) 5122 { 5123 const Elf_Verdef *vd; 5124 const char *vername; 5125 5126 vername = refobj->strtab + vna->vna_name; 5127 vd = depobj->verdef; 5128 if (vd == NULL) { 5129 _rtld_error("%s: version %s required by %s not defined", 5130 depobj->path, vername, refobj->path); 5131 return (-1); 5132 } 5133 for (;;) { 5134 if (vd->vd_version != VER_DEF_CURRENT) { 5135 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5136 depobj->path, vd->vd_version); 5137 return (-1); 5138 } 5139 if (vna->vna_hash == vd->vd_hash) { 5140 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5141 ((const char *)vd + vd->vd_aux); 5142 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5143 return (0); 5144 } 5145 if (vd->vd_next == 0) 5146 break; 5147 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5148 } 5149 if (vna->vna_flags & VER_FLG_WEAK) 5150 return (0); 5151 _rtld_error("%s: version %s required by %s not found", 5152 depobj->path, vername, refobj->path); 5153 return (-1); 5154 } 5155 5156 static int 5157 rtld_verify_object_versions(Obj_Entry *obj) 5158 { 5159 const Elf_Verneed *vn; 5160 const Elf_Verdef *vd; 5161 const Elf_Verdaux *vda; 5162 const Elf_Vernaux *vna; 5163 const Obj_Entry *depobj; 5164 int maxvernum, vernum; 5165 5166 if (obj->ver_checked) 5167 return (0); 5168 obj->ver_checked = true; 5169 5170 maxvernum = 0; 5171 /* 5172 * Walk over defined and required version records and figure out 5173 * max index used by any of them. Do very basic sanity checking 5174 * while there. 5175 */ 5176 vn = obj->verneed; 5177 while (vn != NULL) { 5178 if (vn->vn_version != VER_NEED_CURRENT) { 5179 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5180 obj->path, vn->vn_version); 5181 return (-1); 5182 } 5183 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5184 for (;;) { 5185 vernum = VER_NEED_IDX(vna->vna_other); 5186 if (vernum > maxvernum) 5187 maxvernum = vernum; 5188 if (vna->vna_next == 0) 5189 break; 5190 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5191 } 5192 if (vn->vn_next == 0) 5193 break; 5194 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5195 } 5196 5197 vd = obj->verdef; 5198 while (vd != NULL) { 5199 if (vd->vd_version != VER_DEF_CURRENT) { 5200 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5201 obj->path, vd->vd_version); 5202 return (-1); 5203 } 5204 vernum = VER_DEF_IDX(vd->vd_ndx); 5205 if (vernum > maxvernum) 5206 maxvernum = vernum; 5207 if (vd->vd_next == 0) 5208 break; 5209 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5210 } 5211 5212 if (maxvernum == 0) 5213 return (0); 5214 5215 /* 5216 * Store version information in array indexable by version index. 5217 * Verify that object version requirements are satisfied along the 5218 * way. 5219 */ 5220 obj->vernum = maxvernum + 1; 5221 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5222 5223 vd = obj->verdef; 5224 while (vd != NULL) { 5225 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5226 vernum = VER_DEF_IDX(vd->vd_ndx); 5227 assert(vernum <= maxvernum); 5228 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5229 obj->vertab[vernum].hash = vd->vd_hash; 5230 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5231 obj->vertab[vernum].file = NULL; 5232 obj->vertab[vernum].flags = 0; 5233 } 5234 if (vd->vd_next == 0) 5235 break; 5236 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5237 } 5238 5239 vn = obj->verneed; 5240 while (vn != NULL) { 5241 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5242 if (depobj == NULL) 5243 return (-1); 5244 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5245 for (;;) { 5246 if (check_object_provided_version(obj, depobj, vna)) 5247 return (-1); 5248 vernum = VER_NEED_IDX(vna->vna_other); 5249 assert(vernum <= maxvernum); 5250 obj->vertab[vernum].hash = vna->vna_hash; 5251 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5252 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5253 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5254 VER_INFO_HIDDEN : 0; 5255 if (vna->vna_next == 0) 5256 break; 5257 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5258 } 5259 if (vn->vn_next == 0) 5260 break; 5261 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5262 } 5263 return 0; 5264 } 5265 5266 static int 5267 rtld_verify_versions(const Objlist *objlist) 5268 { 5269 Objlist_Entry *entry; 5270 int rc; 5271 5272 rc = 0; 5273 STAILQ_FOREACH(entry, objlist, link) { 5274 /* 5275 * Skip dummy objects or objects that have their version requirements 5276 * already checked. 5277 */ 5278 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5279 continue; 5280 if (rtld_verify_object_versions(entry->obj) == -1) { 5281 rc = -1; 5282 if (ld_tracing == NULL) 5283 break; 5284 } 5285 } 5286 if (rc == 0 || ld_tracing != NULL) 5287 rc = rtld_verify_object_versions(&obj_rtld); 5288 return rc; 5289 } 5290 5291 const Ver_Entry * 5292 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5293 { 5294 Elf_Versym vernum; 5295 5296 if (obj->vertab) { 5297 vernum = VER_NDX(obj->versyms[symnum]); 5298 if (vernum >= obj->vernum) { 5299 _rtld_error("%s: symbol %s has wrong verneed value %d", 5300 obj->path, obj->strtab + symnum, vernum); 5301 } else if (obj->vertab[vernum].hash != 0) { 5302 return &obj->vertab[vernum]; 5303 } 5304 } 5305 return NULL; 5306 } 5307 5308 int 5309 _rtld_get_stack_prot(void) 5310 { 5311 5312 return (stack_prot); 5313 } 5314 5315 int 5316 _rtld_is_dlopened(void *arg) 5317 { 5318 Obj_Entry *obj; 5319 RtldLockState lockstate; 5320 int res; 5321 5322 rlock_acquire(rtld_bind_lock, &lockstate); 5323 obj = dlcheck(arg); 5324 if (obj == NULL) 5325 obj = obj_from_addr(arg); 5326 if (obj == NULL) { 5327 _rtld_error("No shared object contains address"); 5328 lock_release(rtld_bind_lock, &lockstate); 5329 return (-1); 5330 } 5331 res = obj->dlopened ? 1 : 0; 5332 lock_release(rtld_bind_lock, &lockstate); 5333 return (res); 5334 } 5335 5336 static int 5337 obj_remap_relro(Obj_Entry *obj, int prot) 5338 { 5339 5340 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5341 prot) == -1) { 5342 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5343 obj->path, prot, rtld_strerror(errno)); 5344 return (-1); 5345 } 5346 return (0); 5347 } 5348 5349 static int 5350 obj_disable_relro(Obj_Entry *obj) 5351 { 5352 5353 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5354 } 5355 5356 static int 5357 obj_enforce_relro(Obj_Entry *obj) 5358 { 5359 5360 return (obj_remap_relro(obj, PROT_READ)); 5361 } 5362 5363 static void 5364 map_stacks_exec(RtldLockState *lockstate) 5365 { 5366 void (*thr_map_stacks_exec)(void); 5367 5368 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5369 return; 5370 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5371 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5372 if (thr_map_stacks_exec != NULL) { 5373 stack_prot |= PROT_EXEC; 5374 thr_map_stacks_exec(); 5375 } 5376 } 5377 5378 void 5379 symlook_init(SymLook *dst, const char *name) 5380 { 5381 5382 bzero(dst, sizeof(*dst)); 5383 dst->name = name; 5384 dst->hash = elf_hash(name); 5385 dst->hash_gnu = gnu_hash(name); 5386 } 5387 5388 static void 5389 symlook_init_from_req(SymLook *dst, const SymLook *src) 5390 { 5391 5392 dst->name = src->name; 5393 dst->hash = src->hash; 5394 dst->hash_gnu = src->hash_gnu; 5395 dst->ventry = src->ventry; 5396 dst->flags = src->flags; 5397 dst->defobj_out = NULL; 5398 dst->sym_out = NULL; 5399 dst->lockstate = src->lockstate; 5400 } 5401 5402 static int 5403 open_binary_fd(const char *argv0, bool search_in_path) 5404 { 5405 char *pathenv, *pe, binpath[PATH_MAX]; 5406 int fd; 5407 5408 if (search_in_path && strchr(argv0, '/') == NULL) { 5409 pathenv = getenv("PATH"); 5410 if (pathenv == NULL) { 5411 _rtld_error("-p and no PATH environment variable"); 5412 rtld_die(); 5413 } 5414 pathenv = strdup(pathenv); 5415 if (pathenv == NULL) { 5416 _rtld_error("Cannot allocate memory"); 5417 rtld_die(); 5418 } 5419 fd = -1; 5420 errno = ENOENT; 5421 while ((pe = strsep(&pathenv, ":")) != NULL) { 5422 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5423 sizeof(binpath)) 5424 continue; 5425 if (binpath[0] != '\0' && 5426 strlcat(binpath, "/", sizeof(binpath)) >= 5427 sizeof(binpath)) 5428 continue; 5429 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5430 sizeof(binpath)) 5431 continue; 5432 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5433 if (fd != -1 || errno != ENOENT) 5434 break; 5435 } 5436 free(pathenv); 5437 } else { 5438 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5439 } 5440 5441 if (fd == -1) { 5442 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5443 rtld_die(); 5444 } 5445 return (fd); 5446 } 5447 5448 /* 5449 * Parse a set of command-line arguments. 5450 */ 5451 static int 5452 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5453 { 5454 const char *arg; 5455 int fd, i, j, arglen; 5456 char opt; 5457 5458 dbg("Parsing command-line arguments"); 5459 *use_pathp = false; 5460 *fdp = -1; 5461 5462 for (i = 1; i < argc; i++ ) { 5463 arg = argv[i]; 5464 dbg("argv[%d]: '%s'", i, arg); 5465 5466 /* 5467 * rtld arguments end with an explicit "--" or with the first 5468 * non-prefixed argument. 5469 */ 5470 if (strcmp(arg, "--") == 0) { 5471 i++; 5472 break; 5473 } 5474 if (arg[0] != '-') 5475 break; 5476 5477 /* 5478 * All other arguments are single-character options that can 5479 * be combined, so we need to search through `arg` for them. 5480 */ 5481 arglen = strlen(arg); 5482 for (j = 1; j < arglen; j++) { 5483 opt = arg[j]; 5484 if (opt == 'h') { 5485 print_usage(argv[0]); 5486 _exit(0); 5487 } else if (opt == 'f') { 5488 /* 5489 * -f XX can be used to specify a descriptor for the 5490 * binary named at the command line (i.e., the later 5491 * argument will specify the process name but the 5492 * descriptor is what will actually be executed) 5493 */ 5494 if (j != arglen - 1) { 5495 /* -f must be the last option in, e.g., -abcf */ 5496 _rtld_error("Invalid options: %s", arg); 5497 rtld_die(); 5498 } 5499 i++; 5500 fd = parse_integer(argv[i]); 5501 if (fd == -1) { 5502 _rtld_error("Invalid file descriptor: '%s'", 5503 argv[i]); 5504 rtld_die(); 5505 } 5506 *fdp = fd; 5507 break; 5508 } else if (opt == 'p') { 5509 *use_pathp = true; 5510 } else { 5511 _rtld_error("Invalid argument: '%s'", arg); 5512 print_usage(argv[0]); 5513 rtld_die(); 5514 } 5515 } 5516 } 5517 5518 return (i); 5519 } 5520 5521 /* 5522 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5523 */ 5524 static int 5525 parse_integer(const char *str) 5526 { 5527 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5528 const char *orig; 5529 int n; 5530 char c; 5531 5532 orig = str; 5533 n = 0; 5534 for (c = *str; c != '\0'; c = *++str) { 5535 if (c < '0' || c > '9') 5536 return (-1); 5537 5538 n *= RADIX; 5539 n += c - '0'; 5540 } 5541 5542 /* Make sure we actually parsed something. */ 5543 if (str == orig) 5544 return (-1); 5545 return (n); 5546 } 5547 5548 static void 5549 print_usage(const char *argv0) 5550 { 5551 5552 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5553 "\n" 5554 "Options:\n" 5555 " -h Display this help message\n" 5556 " -p Search in PATH for named binary\n" 5557 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5558 " -- End of RTLD options\n" 5559 " <binary> Name of process to execute\n" 5560 " <args> Arguments to the executed process\n", argv0); 5561 } 5562 5563 /* 5564 * Overrides for libc_pic-provided functions. 5565 */ 5566 5567 int 5568 __getosreldate(void) 5569 { 5570 size_t len; 5571 int oid[2]; 5572 int error, osrel; 5573 5574 if (osreldate != 0) 5575 return (osreldate); 5576 5577 oid[0] = CTL_KERN; 5578 oid[1] = KERN_OSRELDATE; 5579 osrel = 0; 5580 len = sizeof(osrel); 5581 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5582 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5583 osreldate = osrel; 5584 return (osreldate); 5585 } 5586 5587 void 5588 exit(int status) 5589 { 5590 5591 _exit(status); 5592 } 5593 5594 void (*__cleanup)(void); 5595 int __isthreaded = 0; 5596 int _thread_autoinit_dummy_decl = 1; 5597 5598 /* 5599 * No unresolved symbols for rtld. 5600 */ 5601 void 5602 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5603 { 5604 } 5605 5606 const char * 5607 rtld_strerror(int errnum) 5608 { 5609 5610 if (errnum < 0 || errnum >= sys_nerr) 5611 return ("Unknown error"); 5612 return (sys_errlist[errnum]); 5613 } 5614 5615 /* 5616 * No ifunc relocations. 5617 */ 5618 void * 5619 memset(void *dest, int c, size_t len) 5620 { 5621 size_t i; 5622 5623 for (i = 0; i < len; i++) 5624 ((char *)dest)[i] = c; 5625 return (dest); 5626 } 5627 5628 void 5629 bzero(void *dest, size_t len) 5630 { 5631 size_t i; 5632 5633 for (i = 0; i < len; i++) 5634 ((char *)dest)[i] = 0; 5635 } 5636 5637 /* malloc */ 5638 void * 5639 malloc(size_t nbytes) 5640 { 5641 5642 return (__crt_malloc(nbytes)); 5643 } 5644 5645 void * 5646 calloc(size_t num, size_t size) 5647 { 5648 5649 return (__crt_calloc(num, size)); 5650 } 5651 5652 void 5653 free(void *cp) 5654 { 5655 5656 __crt_free(cp); 5657 } 5658 5659 void * 5660 realloc(void *cp, size_t nbytes) 5661 { 5662 5663 return (__crt_realloc(cp, nbytes)); 5664 } 5665