1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_utrace.h" 70 #include "notes.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(void); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 77 /* Variables that cannot be static: */ 78 extern struct r_debug r_debug; /* For GDB */ 79 extern int _thread_autoinit_dummy_decl; 80 extern char* __progname; 81 extern void (*__cleanup)(void); 82 83 84 /* 85 * Function declarations. 86 */ 87 static const char *basename(const char *); 88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 89 const Elf_Dyn **, const Elf_Dyn **); 90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 91 const Elf_Dyn *); 92 static void digest_dynamic(Obj_Entry *, int); 93 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 94 static Obj_Entry *dlcheck(void *); 95 static int dlclose_locked(void *, RtldLockState *); 96 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 97 int lo_flags, int mode, RtldLockState *lockstate); 98 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 99 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 100 static bool donelist_check(DoneList *, const Obj_Entry *); 101 static void errmsg_restore(char *); 102 static char *errmsg_save(void); 103 static void *fill_search_info(const char *, size_t, void *); 104 static char *find_library(const char *, const Obj_Entry *, int *); 105 static const char *gethints(bool); 106 static void hold_object(Obj_Entry *); 107 static void unhold_object(Obj_Entry *); 108 static void init_dag(Obj_Entry *); 109 static void init_marker(Obj_Entry *); 110 static void init_pagesizes(Elf_Auxinfo **aux_info); 111 static void init_rtld(caddr_t, Elf_Auxinfo **); 112 static void initlist_add_neededs(Needed_Entry *, Objlist *); 113 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 114 static void linkmap_add(Obj_Entry *); 115 static void linkmap_delete(Obj_Entry *); 116 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 117 static void unload_filtees(Obj_Entry *, RtldLockState *); 118 static int load_needed_objects(Obj_Entry *, int); 119 static int load_preload_objects(void); 120 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 121 static void map_stacks_exec(RtldLockState *); 122 static int obj_enforce_relro(Obj_Entry *); 123 static Obj_Entry *obj_from_addr(const void *); 124 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 125 static void objlist_call_init(Objlist *, RtldLockState *); 126 static void objlist_clear(Objlist *); 127 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 128 static void objlist_init(Objlist *); 129 static void objlist_push_head(Objlist *, Obj_Entry *); 130 static void objlist_push_tail(Objlist *, Obj_Entry *); 131 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 132 static void objlist_remove(Objlist *, Obj_Entry *); 133 static int open_binary_fd(const char *argv0, bool search_in_path); 134 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 135 static int parse_integer(const char *); 136 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 137 static void print_usage(const char *argv0); 138 static void release_object(Obj_Entry *); 139 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 140 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 141 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 142 int flags, RtldLockState *lockstate); 143 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 144 RtldLockState *); 145 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 146 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 147 int flags, RtldLockState *lockstate); 148 static int rtld_dirname(const char *, char *); 149 static int rtld_dirname_abs(const char *, char *); 150 static void *rtld_dlopen(const char *name, int fd, int mode); 151 static void rtld_exit(void); 152 static char *search_library_path(const char *, const char *, const char *, 153 int *); 154 static char *search_library_pathfds(const char *, const char *, int *); 155 static const void **get_program_var_addr(const char *, RtldLockState *); 156 static void set_program_var(const char *, const void *); 157 static int symlook_default(SymLook *, const Obj_Entry *refobj); 158 static int symlook_global(SymLook *, DoneList *); 159 static void symlook_init_from_req(SymLook *, const SymLook *); 160 static int symlook_list(SymLook *, const Objlist *, DoneList *); 161 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 162 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 163 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 164 static void trace_loaded_objects(Obj_Entry *); 165 static void unlink_object(Obj_Entry *); 166 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 167 static void unref_dag(Obj_Entry *); 168 static void ref_dag(Obj_Entry *); 169 static char *origin_subst_one(Obj_Entry *, char *, const char *, 170 const char *, bool); 171 static char *origin_subst(Obj_Entry *, const char *); 172 static bool obj_resolve_origin(Obj_Entry *obj); 173 static void preinit_main(void); 174 static int rtld_verify_versions(const Objlist *); 175 static int rtld_verify_object_versions(Obj_Entry *); 176 static void object_add_name(Obj_Entry *, const char *); 177 static int object_match_name(const Obj_Entry *, const char *); 178 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 179 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 180 struct dl_phdr_info *phdr_info); 181 static uint32_t gnu_hash(const char *); 182 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 183 const unsigned long); 184 185 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 186 void _r_debug_postinit(struct link_map *) __noinline __exported; 187 188 int __sys_openat(int, const char *, int, ...); 189 190 /* 191 * Data declarations. 192 */ 193 static char *error_message; /* Message for dlerror(), or NULL */ 194 struct r_debug r_debug __exported; /* for GDB; */ 195 static bool libmap_disable; /* Disable libmap */ 196 static bool ld_loadfltr; /* Immediate filters processing */ 197 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 198 static bool trust; /* False for setuid and setgid programs */ 199 static bool dangerous_ld_env; /* True if environment variables have been 200 used to affect the libraries loaded */ 201 bool ld_bind_not; /* Disable PLT update */ 202 static char *ld_bind_now; /* Environment variable for immediate binding */ 203 static char *ld_debug; /* Environment variable for debugging */ 204 static char *ld_library_path; /* Environment variable for search path */ 205 static char *ld_library_dirs; /* Environment variable for library descriptors */ 206 static char *ld_preload; /* Environment variable for libraries to 207 load first */ 208 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 209 static const char *ld_tracing; /* Called from ldd to print libs */ 210 static char *ld_utrace; /* Use utrace() to log events. */ 211 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 212 static Obj_Entry *obj_main; /* The main program shared object */ 213 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 214 static unsigned int obj_count; /* Number of objects in obj_list */ 215 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 216 217 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 218 STAILQ_HEAD_INITIALIZER(list_global); 219 static Objlist list_main = /* Objects loaded at program startup */ 220 STAILQ_HEAD_INITIALIZER(list_main); 221 static Objlist list_fini = /* Objects needing fini() calls */ 222 STAILQ_HEAD_INITIALIZER(list_fini); 223 224 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 225 226 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 227 228 extern Elf_Dyn _DYNAMIC; 229 #pragma weak _DYNAMIC 230 231 int dlclose(void *) __exported; 232 char *dlerror(void) __exported; 233 void *dlopen(const char *, int) __exported; 234 void *fdlopen(int, int) __exported; 235 void *dlsym(void *, const char *) __exported; 236 dlfunc_t dlfunc(void *, const char *) __exported; 237 void *dlvsym(void *, const char *, const char *) __exported; 238 int dladdr(const void *, Dl_info *) __exported; 239 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 240 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 241 int dlinfo(void *, int , void *) __exported; 242 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 243 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 244 int _rtld_get_stack_prot(void) __exported; 245 int _rtld_is_dlopened(void *) __exported; 246 void _rtld_error(const char *, ...) __exported; 247 248 /* Only here to fix -Wmissing-prototypes warnings */ 249 int __getosreldate(void); 250 void __pthread_cxa_finalize(struct dl_phdr_info *a); 251 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 252 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 253 254 255 int npagesizes; 256 static int osreldate; 257 size_t *pagesizes; 258 259 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 260 static int max_stack_flags; 261 262 /* 263 * Global declarations normally provided by crt1. The dynamic linker is 264 * not built with crt1, so we have to provide them ourselves. 265 */ 266 char *__progname; 267 char **environ; 268 269 /* 270 * Used to pass argc, argv to init functions. 271 */ 272 int main_argc; 273 char **main_argv; 274 275 /* 276 * Globals to control TLS allocation. 277 */ 278 size_t tls_last_offset; /* Static TLS offset of last module */ 279 size_t tls_last_size; /* Static TLS size of last module */ 280 size_t tls_static_space; /* Static TLS space allocated */ 281 static size_t tls_static_max_align; 282 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 283 int tls_max_index = 1; /* Largest module index allocated */ 284 285 static bool ld_library_path_rpath = false; 286 287 /* 288 * Globals for path names, and such 289 */ 290 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 291 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 292 const char *ld_path_rtld = _PATH_RTLD; 293 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 294 const char *ld_env_prefix = LD_; 295 296 /* 297 * Fill in a DoneList with an allocation large enough to hold all of 298 * the currently-loaded objects. Keep this as a macro since it calls 299 * alloca and we want that to occur within the scope of the caller. 300 */ 301 #define donelist_init(dlp) \ 302 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 303 assert((dlp)->objs != NULL), \ 304 (dlp)->num_alloc = obj_count, \ 305 (dlp)->num_used = 0) 306 307 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 308 if (ld_utrace != NULL) \ 309 ld_utrace_log(e, h, mb, ms, r, n); \ 310 } while (0) 311 312 static void 313 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 314 int refcnt, const char *name) 315 { 316 struct utrace_rtld ut; 317 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 318 319 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 320 ut.event = event; 321 ut.handle = handle; 322 ut.mapbase = mapbase; 323 ut.mapsize = mapsize; 324 ut.refcnt = refcnt; 325 bzero(ut.name, sizeof(ut.name)); 326 if (name) 327 strlcpy(ut.name, name, sizeof(ut.name)); 328 utrace(&ut, sizeof(ut)); 329 } 330 331 #ifdef RTLD_VARIANT_ENV_NAMES 332 /* 333 * construct the env variable based on the type of binary that's 334 * running. 335 */ 336 static inline const char * 337 _LD(const char *var) 338 { 339 static char buffer[128]; 340 341 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 342 strlcat(buffer, var, sizeof(buffer)); 343 return (buffer); 344 } 345 #else 346 #define _LD(x) LD_ x 347 #endif 348 349 /* 350 * Main entry point for dynamic linking. The first argument is the 351 * stack pointer. The stack is expected to be laid out as described 352 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 353 * Specifically, the stack pointer points to a word containing 354 * ARGC. Following that in the stack is a null-terminated sequence 355 * of pointers to argument strings. Then comes a null-terminated 356 * sequence of pointers to environment strings. Finally, there is a 357 * sequence of "auxiliary vector" entries. 358 * 359 * The second argument points to a place to store the dynamic linker's 360 * exit procedure pointer and the third to a place to store the main 361 * program's object. 362 * 363 * The return value is the main program's entry point. 364 */ 365 func_ptr_type 366 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 367 { 368 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 369 Objlist_Entry *entry; 370 Obj_Entry *last_interposer, *obj, *preload_tail; 371 const Elf_Phdr *phdr; 372 Objlist initlist; 373 RtldLockState lockstate; 374 struct stat st; 375 Elf_Addr *argcp; 376 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 377 const char *argv0; 378 caddr_t imgentry; 379 char buf[MAXPATHLEN]; 380 int argc, fd, i, phnum, rtld_argc; 381 bool dir_enable, explicit_fd, search_in_path; 382 383 /* 384 * On entry, the dynamic linker itself has not been relocated yet. 385 * Be very careful not to reference any global data until after 386 * init_rtld has returned. It is OK to reference file-scope statics 387 * and string constants, and to call static and global functions. 388 */ 389 390 /* Find the auxiliary vector on the stack. */ 391 argcp = sp; 392 argc = *sp++; 393 argv = (char **) sp; 394 sp += argc + 1; /* Skip over arguments and NULL terminator */ 395 env = (char **) sp; 396 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 397 ; 398 aux = (Elf_Auxinfo *) sp; 399 400 /* Digest the auxiliary vector. */ 401 for (i = 0; i < AT_COUNT; i++) 402 aux_info[i] = NULL; 403 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 404 if (auxp->a_type < AT_COUNT) 405 aux_info[auxp->a_type] = auxp; 406 } 407 408 /* Initialize and relocate ourselves. */ 409 assert(aux_info[AT_BASE] != NULL); 410 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 411 412 __progname = obj_rtld.path; 413 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 414 environ = env; 415 main_argc = argc; 416 main_argv = argv; 417 418 trust = !issetugid(); 419 420 md_abi_variant_hook(aux_info); 421 422 fd = -1; 423 if (aux_info[AT_EXECFD] != NULL) { 424 fd = aux_info[AT_EXECFD]->a_un.a_val; 425 } else { 426 assert(aux_info[AT_PHDR] != NULL); 427 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 428 if (phdr == obj_rtld.phdr) { 429 if (!trust) { 430 _rtld_error("Tainted process refusing to run binary %s", 431 argv0); 432 rtld_die(); 433 } 434 dbg("opening main program in direct exec mode"); 435 if (argc >= 2) { 436 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 437 argv0 = argv[rtld_argc]; 438 explicit_fd = (fd != -1); 439 if (!explicit_fd) 440 fd = open_binary_fd(argv0, search_in_path); 441 if (fstat(fd, &st) == -1) { 442 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 443 explicit_fd ? "user-provided descriptor" : argv0, 444 rtld_strerror(errno)); 445 rtld_die(); 446 } 447 448 /* 449 * Rough emulation of the permission checks done by 450 * execve(2), only Unix DACs are checked, ACLs are 451 * ignored. Preserve the semantic of disabling owner 452 * to execute if owner x bit is cleared, even if 453 * others x bit is enabled. 454 * mmap(2) does not allow to mmap with PROT_EXEC if 455 * binary' file comes from noexec mount. We cannot 456 * set VV_TEXT on the binary. 457 */ 458 dir_enable = false; 459 if (st.st_uid == geteuid()) { 460 if ((st.st_mode & S_IXUSR) != 0) 461 dir_enable = true; 462 } else if (st.st_gid == getegid()) { 463 if ((st.st_mode & S_IXGRP) != 0) 464 dir_enable = true; 465 } else if ((st.st_mode & S_IXOTH) != 0) { 466 dir_enable = true; 467 } 468 if (!dir_enable) { 469 _rtld_error("No execute permission for binary %s", 470 argv0); 471 rtld_die(); 472 } 473 474 /* 475 * For direct exec mode, argv[0] is the interpreter 476 * name, we must remove it and shift arguments left 477 * before invoking binary main. Since stack layout 478 * places environment pointers and aux vectors right 479 * after the terminating NULL, we must shift 480 * environment and aux as well. 481 */ 482 main_argc = argc - rtld_argc; 483 for (i = 0; i <= main_argc; i++) 484 argv[i] = argv[i + rtld_argc]; 485 *argcp -= rtld_argc; 486 environ = env = envp = argv + main_argc + 1; 487 do { 488 *envp = *(envp + rtld_argc); 489 envp++; 490 } while (*envp != NULL); 491 aux = auxp = (Elf_Auxinfo *)envp; 492 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 493 for (;; auxp++, auxpf++) { 494 *auxp = *auxpf; 495 if (auxp->a_type == AT_NULL) 496 break; 497 } 498 } else { 499 _rtld_error("No binary"); 500 rtld_die(); 501 } 502 } 503 } 504 505 ld_bind_now = getenv(_LD("BIND_NOW")); 506 507 /* 508 * If the process is tainted, then we un-set the dangerous environment 509 * variables. The process will be marked as tainted until setuid(2) 510 * is called. If any child process calls setuid(2) we do not want any 511 * future processes to honor the potentially un-safe variables. 512 */ 513 if (!trust) { 514 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 515 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 516 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 517 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 518 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 519 _rtld_error("environment corrupt; aborting"); 520 rtld_die(); 521 } 522 } 523 ld_debug = getenv(_LD("DEBUG")); 524 if (ld_bind_now == NULL) 525 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 526 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 527 libmap_override = getenv(_LD("LIBMAP")); 528 ld_library_path = getenv(_LD("LIBRARY_PATH")); 529 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 530 ld_preload = getenv(_LD("PRELOAD")); 531 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 532 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 533 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 534 if (library_path_rpath != NULL) { 535 if (library_path_rpath[0] == 'y' || 536 library_path_rpath[0] == 'Y' || 537 library_path_rpath[0] == '1') 538 ld_library_path_rpath = true; 539 else 540 ld_library_path_rpath = false; 541 } 542 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 543 (ld_library_path != NULL) || (ld_preload != NULL) || 544 (ld_elf_hints_path != NULL) || ld_loadfltr; 545 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 546 ld_utrace = getenv(_LD("UTRACE")); 547 548 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 549 ld_elf_hints_path = ld_elf_hints_default; 550 551 if (ld_debug != NULL && *ld_debug != '\0') 552 debug = 1; 553 dbg("%s is initialized, base address = %p", __progname, 554 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 555 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 556 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 557 558 dbg("initializing thread locks"); 559 lockdflt_init(); 560 561 /* 562 * Load the main program, or process its program header if it is 563 * already loaded. 564 */ 565 if (fd != -1) { /* Load the main program. */ 566 dbg("loading main program"); 567 obj_main = map_object(fd, argv0, NULL); 568 close(fd); 569 if (obj_main == NULL) 570 rtld_die(); 571 max_stack_flags = obj_main->stack_flags; 572 } else { /* Main program already loaded. */ 573 dbg("processing main program's program header"); 574 assert(aux_info[AT_PHDR] != NULL); 575 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 576 assert(aux_info[AT_PHNUM] != NULL); 577 phnum = aux_info[AT_PHNUM]->a_un.a_val; 578 assert(aux_info[AT_PHENT] != NULL); 579 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 580 assert(aux_info[AT_ENTRY] != NULL); 581 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 582 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 583 rtld_die(); 584 } 585 586 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 587 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 588 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 589 if (kexecpath[0] == '/') 590 obj_main->path = kexecpath; 591 else if (getcwd(buf, sizeof(buf)) == NULL || 592 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 593 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 594 obj_main->path = xstrdup(argv0); 595 else 596 obj_main->path = xstrdup(buf); 597 } else { 598 dbg("No AT_EXECPATH or direct exec"); 599 obj_main->path = xstrdup(argv0); 600 } 601 dbg("obj_main path %s", obj_main->path); 602 obj_main->mainprog = true; 603 604 if (aux_info[AT_STACKPROT] != NULL && 605 aux_info[AT_STACKPROT]->a_un.a_val != 0) 606 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 607 608 #ifndef COMPAT_32BIT 609 /* 610 * Get the actual dynamic linker pathname from the executable if 611 * possible. (It should always be possible.) That ensures that 612 * gdb will find the right dynamic linker even if a non-standard 613 * one is being used. 614 */ 615 if (obj_main->interp != NULL && 616 strcmp(obj_main->interp, obj_rtld.path) != 0) { 617 free(obj_rtld.path); 618 obj_rtld.path = xstrdup(obj_main->interp); 619 __progname = obj_rtld.path; 620 } 621 #endif 622 623 digest_dynamic(obj_main, 0); 624 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 625 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 626 obj_main->dynsymcount); 627 628 linkmap_add(obj_main); 629 linkmap_add(&obj_rtld); 630 631 /* Link the main program into the list of objects. */ 632 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 633 obj_count++; 634 obj_loads++; 635 636 /* Initialize a fake symbol for resolving undefined weak references. */ 637 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 638 sym_zero.st_shndx = SHN_UNDEF; 639 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 640 641 if (!libmap_disable) 642 libmap_disable = (bool)lm_init(libmap_override); 643 644 dbg("loading LD_PRELOAD libraries"); 645 if (load_preload_objects() == -1) 646 rtld_die(); 647 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 648 649 dbg("loading needed objects"); 650 if (load_needed_objects(obj_main, 0) == -1) 651 rtld_die(); 652 653 /* Make a list of all objects loaded at startup. */ 654 last_interposer = obj_main; 655 TAILQ_FOREACH(obj, &obj_list, next) { 656 if (obj->marker) 657 continue; 658 if (obj->z_interpose && obj != obj_main) { 659 objlist_put_after(&list_main, last_interposer, obj); 660 last_interposer = obj; 661 } else { 662 objlist_push_tail(&list_main, obj); 663 } 664 obj->refcount++; 665 } 666 667 dbg("checking for required versions"); 668 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 669 rtld_die(); 670 671 if (ld_tracing) { /* We're done */ 672 trace_loaded_objects(obj_main); 673 exit(0); 674 } 675 676 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 677 dump_relocations(obj_main); 678 exit (0); 679 } 680 681 /* 682 * Processing tls relocations requires having the tls offsets 683 * initialized. Prepare offsets before starting initial 684 * relocation processing. 685 */ 686 dbg("initializing initial thread local storage offsets"); 687 STAILQ_FOREACH(entry, &list_main, link) { 688 /* 689 * Allocate all the initial objects out of the static TLS 690 * block even if they didn't ask for it. 691 */ 692 allocate_tls_offset(entry->obj); 693 } 694 695 if (relocate_objects(obj_main, 696 ld_bind_now != NULL && *ld_bind_now != '\0', 697 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 698 rtld_die(); 699 700 dbg("doing copy relocations"); 701 if (do_copy_relocations(obj_main) == -1) 702 rtld_die(); 703 704 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 705 dump_relocations(obj_main); 706 exit (0); 707 } 708 709 ifunc_init(aux); 710 711 /* 712 * Setup TLS for main thread. This must be done after the 713 * relocations are processed, since tls initialization section 714 * might be the subject for relocations. 715 */ 716 dbg("initializing initial thread local storage"); 717 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 718 719 dbg("initializing key program variables"); 720 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 721 set_program_var("environ", env); 722 set_program_var("__elf_aux_vector", aux); 723 724 /* Make a list of init functions to call. */ 725 objlist_init(&initlist); 726 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 727 preload_tail, &initlist); 728 729 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 730 731 map_stacks_exec(NULL); 732 733 dbg("resolving ifuncs"); 734 if (resolve_objects_ifunc(obj_main, 735 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 736 NULL) == -1) 737 rtld_die(); 738 739 dbg("enforcing main obj relro"); 740 if (obj_enforce_relro(obj_main) == -1) 741 rtld_die(); 742 743 if (!obj_main->crt_no_init) { 744 /* 745 * Make sure we don't call the main program's init and fini 746 * functions for binaries linked with old crt1 which calls 747 * _init itself. 748 */ 749 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 750 obj_main->preinit_array = obj_main->init_array = 751 obj_main->fini_array = (Elf_Addr)NULL; 752 } 753 754 /* 755 * Execute MD initializers required before we call the objects' 756 * init functions. 757 */ 758 pre_init(); 759 760 wlock_acquire(rtld_bind_lock, &lockstate); 761 if (obj_main->crt_no_init) 762 preinit_main(); 763 objlist_call_init(&initlist, &lockstate); 764 _r_debug_postinit(&obj_main->linkmap); 765 objlist_clear(&initlist); 766 dbg("loading filtees"); 767 TAILQ_FOREACH(obj, &obj_list, next) { 768 if (obj->marker) 769 continue; 770 if (ld_loadfltr || obj->z_loadfltr) 771 load_filtees(obj, 0, &lockstate); 772 } 773 lock_release(rtld_bind_lock, &lockstate); 774 775 dbg("transferring control to program entry point = %p", obj_main->entry); 776 777 /* Return the exit procedure and the program entry point. */ 778 *exit_proc = rtld_exit; 779 *objp = obj_main; 780 return (func_ptr_type) obj_main->entry; 781 } 782 783 void * 784 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 785 { 786 void *ptr; 787 Elf_Addr target; 788 789 ptr = (void *)make_function_pointer(def, obj); 790 target = call_ifunc_resolver(ptr); 791 return ((void *)target); 792 } 793 794 /* 795 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 796 * Changes to this function should be applied there as well. 797 */ 798 Elf_Addr 799 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 800 { 801 const Elf_Rel *rel; 802 const Elf_Sym *def; 803 const Obj_Entry *defobj; 804 Elf_Addr *where; 805 Elf_Addr target; 806 RtldLockState lockstate; 807 808 rlock_acquire(rtld_bind_lock, &lockstate); 809 if (sigsetjmp(lockstate.env, 0) != 0) 810 lock_upgrade(rtld_bind_lock, &lockstate); 811 if (obj->pltrel) 812 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 813 else 814 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 815 816 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 817 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 818 NULL, &lockstate); 819 if (def == NULL) 820 rtld_die(); 821 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 822 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 823 else 824 target = (Elf_Addr)(defobj->relocbase + def->st_value); 825 826 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 827 defobj->strtab + def->st_name, basename(obj->path), 828 (void *)target, basename(defobj->path)); 829 830 /* 831 * Write the new contents for the jmpslot. Note that depending on 832 * architecture, the value which we need to return back to the 833 * lazy binding trampoline may or may not be the target 834 * address. The value returned from reloc_jmpslot() is the value 835 * that the trampoline needs. 836 */ 837 target = reloc_jmpslot(where, target, defobj, obj, rel); 838 lock_release(rtld_bind_lock, &lockstate); 839 return target; 840 } 841 842 /* 843 * Error reporting function. Use it like printf. If formats the message 844 * into a buffer, and sets things up so that the next call to dlerror() 845 * will return the message. 846 */ 847 void 848 _rtld_error(const char *fmt, ...) 849 { 850 static char buf[512]; 851 va_list ap; 852 853 va_start(ap, fmt); 854 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 855 error_message = buf; 856 va_end(ap); 857 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 858 } 859 860 /* 861 * Return a dynamically-allocated copy of the current error message, if any. 862 */ 863 static char * 864 errmsg_save(void) 865 { 866 return error_message == NULL ? NULL : xstrdup(error_message); 867 } 868 869 /* 870 * Restore the current error message from a copy which was previously saved 871 * by errmsg_save(). The copy is freed. 872 */ 873 static void 874 errmsg_restore(char *saved_msg) 875 { 876 if (saved_msg == NULL) 877 error_message = NULL; 878 else { 879 _rtld_error("%s", saved_msg); 880 free(saved_msg); 881 } 882 } 883 884 static const char * 885 basename(const char *name) 886 { 887 const char *p = strrchr(name, '/'); 888 return p != NULL ? p + 1 : name; 889 } 890 891 static struct utsname uts; 892 893 static char * 894 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 895 const char *subst, bool may_free) 896 { 897 char *p, *p1, *res, *resp; 898 int subst_len, kw_len, subst_count, old_len, new_len; 899 900 kw_len = strlen(kw); 901 902 /* 903 * First, count the number of the keyword occurrences, to 904 * preallocate the final string. 905 */ 906 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 907 p1 = strstr(p, kw); 908 if (p1 == NULL) 909 break; 910 } 911 912 /* 913 * If the keyword is not found, just return. 914 * 915 * Return non-substituted string if resolution failed. We 916 * cannot do anything more reasonable, the failure mode of the 917 * caller is unresolved library anyway. 918 */ 919 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 920 return (may_free ? real : xstrdup(real)); 921 if (obj != NULL) 922 subst = obj->origin_path; 923 924 /* 925 * There is indeed something to substitute. Calculate the 926 * length of the resulting string, and allocate it. 927 */ 928 subst_len = strlen(subst); 929 old_len = strlen(real); 930 new_len = old_len + (subst_len - kw_len) * subst_count; 931 res = xmalloc(new_len + 1); 932 933 /* 934 * Now, execute the substitution loop. 935 */ 936 for (p = real, resp = res, *resp = '\0';;) { 937 p1 = strstr(p, kw); 938 if (p1 != NULL) { 939 /* Copy the prefix before keyword. */ 940 memcpy(resp, p, p1 - p); 941 resp += p1 - p; 942 /* Keyword replacement. */ 943 memcpy(resp, subst, subst_len); 944 resp += subst_len; 945 *resp = '\0'; 946 p = p1 + kw_len; 947 } else 948 break; 949 } 950 951 /* Copy to the end of string and finish. */ 952 strcat(resp, p); 953 if (may_free) 954 free(real); 955 return (res); 956 } 957 958 static char * 959 origin_subst(Obj_Entry *obj, const char *real) 960 { 961 char *res1, *res2, *res3, *res4; 962 963 if (obj == NULL || !trust) 964 return (xstrdup(real)); 965 if (uts.sysname[0] == '\0') { 966 if (uname(&uts) != 0) { 967 _rtld_error("utsname failed: %d", errno); 968 return (NULL); 969 } 970 } 971 /* __DECONST is safe here since without may_free real is unchanged */ 972 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 973 false); 974 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 975 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 976 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 977 return (res4); 978 } 979 980 void 981 rtld_die(void) 982 { 983 const char *msg = dlerror(); 984 985 if (msg == NULL) 986 msg = "Fatal error"; 987 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 988 rtld_fdputstr(STDERR_FILENO, msg); 989 rtld_fdputchar(STDERR_FILENO, '\n'); 990 _exit(1); 991 } 992 993 /* 994 * Process a shared object's DYNAMIC section, and save the important 995 * information in its Obj_Entry structure. 996 */ 997 static void 998 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 999 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1000 { 1001 const Elf_Dyn *dynp; 1002 Needed_Entry **needed_tail = &obj->needed; 1003 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1004 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1005 const Elf_Hashelt *hashtab; 1006 const Elf32_Word *hashval; 1007 Elf32_Word bkt, nmaskwords; 1008 int bloom_size32; 1009 int plttype = DT_REL; 1010 1011 *dyn_rpath = NULL; 1012 *dyn_soname = NULL; 1013 *dyn_runpath = NULL; 1014 1015 obj->bind_now = false; 1016 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1017 switch (dynp->d_tag) { 1018 1019 case DT_REL: 1020 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1021 break; 1022 1023 case DT_RELSZ: 1024 obj->relsize = dynp->d_un.d_val; 1025 break; 1026 1027 case DT_RELENT: 1028 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1029 break; 1030 1031 case DT_JMPREL: 1032 obj->pltrel = (const Elf_Rel *) 1033 (obj->relocbase + dynp->d_un.d_ptr); 1034 break; 1035 1036 case DT_PLTRELSZ: 1037 obj->pltrelsize = dynp->d_un.d_val; 1038 break; 1039 1040 case DT_RELA: 1041 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1042 break; 1043 1044 case DT_RELASZ: 1045 obj->relasize = dynp->d_un.d_val; 1046 break; 1047 1048 case DT_RELAENT: 1049 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1050 break; 1051 1052 case DT_PLTREL: 1053 plttype = dynp->d_un.d_val; 1054 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1055 break; 1056 1057 case DT_SYMTAB: 1058 obj->symtab = (const Elf_Sym *) 1059 (obj->relocbase + dynp->d_un.d_ptr); 1060 break; 1061 1062 case DT_SYMENT: 1063 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1064 break; 1065 1066 case DT_STRTAB: 1067 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1068 break; 1069 1070 case DT_STRSZ: 1071 obj->strsize = dynp->d_un.d_val; 1072 break; 1073 1074 case DT_VERNEED: 1075 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1076 dynp->d_un.d_val); 1077 break; 1078 1079 case DT_VERNEEDNUM: 1080 obj->verneednum = dynp->d_un.d_val; 1081 break; 1082 1083 case DT_VERDEF: 1084 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1085 dynp->d_un.d_val); 1086 break; 1087 1088 case DT_VERDEFNUM: 1089 obj->verdefnum = dynp->d_un.d_val; 1090 break; 1091 1092 case DT_VERSYM: 1093 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1094 dynp->d_un.d_val); 1095 break; 1096 1097 case DT_HASH: 1098 { 1099 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1100 dynp->d_un.d_ptr); 1101 obj->nbuckets = hashtab[0]; 1102 obj->nchains = hashtab[1]; 1103 obj->buckets = hashtab + 2; 1104 obj->chains = obj->buckets + obj->nbuckets; 1105 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1106 obj->buckets != NULL; 1107 } 1108 break; 1109 1110 case DT_GNU_HASH: 1111 { 1112 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1113 dynp->d_un.d_ptr); 1114 obj->nbuckets_gnu = hashtab[0]; 1115 obj->symndx_gnu = hashtab[1]; 1116 nmaskwords = hashtab[2]; 1117 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1118 obj->maskwords_bm_gnu = nmaskwords - 1; 1119 obj->shift2_gnu = hashtab[3]; 1120 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1121 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1122 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1123 obj->symndx_gnu; 1124 /* Number of bitmask words is required to be power of 2 */ 1125 obj->valid_hash_gnu = powerof2(nmaskwords) && 1126 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1127 } 1128 break; 1129 1130 case DT_NEEDED: 1131 if (!obj->rtld) { 1132 Needed_Entry *nep = NEW(Needed_Entry); 1133 nep->name = dynp->d_un.d_val; 1134 nep->obj = NULL; 1135 nep->next = NULL; 1136 1137 *needed_tail = nep; 1138 needed_tail = &nep->next; 1139 } 1140 break; 1141 1142 case DT_FILTER: 1143 if (!obj->rtld) { 1144 Needed_Entry *nep = NEW(Needed_Entry); 1145 nep->name = dynp->d_un.d_val; 1146 nep->obj = NULL; 1147 nep->next = NULL; 1148 1149 *needed_filtees_tail = nep; 1150 needed_filtees_tail = &nep->next; 1151 } 1152 break; 1153 1154 case DT_AUXILIARY: 1155 if (!obj->rtld) { 1156 Needed_Entry *nep = NEW(Needed_Entry); 1157 nep->name = dynp->d_un.d_val; 1158 nep->obj = NULL; 1159 nep->next = NULL; 1160 1161 *needed_aux_filtees_tail = nep; 1162 needed_aux_filtees_tail = &nep->next; 1163 } 1164 break; 1165 1166 case DT_PLTGOT: 1167 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1168 break; 1169 1170 case DT_TEXTREL: 1171 obj->textrel = true; 1172 break; 1173 1174 case DT_SYMBOLIC: 1175 obj->symbolic = true; 1176 break; 1177 1178 case DT_RPATH: 1179 /* 1180 * We have to wait until later to process this, because we 1181 * might not have gotten the address of the string table yet. 1182 */ 1183 *dyn_rpath = dynp; 1184 break; 1185 1186 case DT_SONAME: 1187 *dyn_soname = dynp; 1188 break; 1189 1190 case DT_RUNPATH: 1191 *dyn_runpath = dynp; 1192 break; 1193 1194 case DT_INIT: 1195 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1196 break; 1197 1198 case DT_PREINIT_ARRAY: 1199 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1200 break; 1201 1202 case DT_PREINIT_ARRAYSZ: 1203 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1204 break; 1205 1206 case DT_INIT_ARRAY: 1207 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1208 break; 1209 1210 case DT_INIT_ARRAYSZ: 1211 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1212 break; 1213 1214 case DT_FINI: 1215 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1216 break; 1217 1218 case DT_FINI_ARRAY: 1219 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1220 break; 1221 1222 case DT_FINI_ARRAYSZ: 1223 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1224 break; 1225 1226 /* 1227 * Don't process DT_DEBUG on MIPS as the dynamic section 1228 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1229 */ 1230 1231 #ifndef __mips__ 1232 case DT_DEBUG: 1233 if (!early) 1234 dbg("Filling in DT_DEBUG entry"); 1235 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1236 break; 1237 #endif 1238 1239 case DT_FLAGS: 1240 if (dynp->d_un.d_val & DF_ORIGIN) 1241 obj->z_origin = true; 1242 if (dynp->d_un.d_val & DF_SYMBOLIC) 1243 obj->symbolic = true; 1244 if (dynp->d_un.d_val & DF_TEXTREL) 1245 obj->textrel = true; 1246 if (dynp->d_un.d_val & DF_BIND_NOW) 1247 obj->bind_now = true; 1248 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1249 ;*/ 1250 break; 1251 #ifdef __mips__ 1252 case DT_MIPS_LOCAL_GOTNO: 1253 obj->local_gotno = dynp->d_un.d_val; 1254 break; 1255 1256 case DT_MIPS_SYMTABNO: 1257 obj->symtabno = dynp->d_un.d_val; 1258 break; 1259 1260 case DT_MIPS_GOTSYM: 1261 obj->gotsym = dynp->d_un.d_val; 1262 break; 1263 1264 case DT_MIPS_RLD_MAP: 1265 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1266 break; 1267 1268 case DT_MIPS_RLD_MAP_REL: 1269 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1270 // section relative to the address of the tag itself. 1271 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1272 (Elf_Addr) &r_debug; 1273 break; 1274 1275 case DT_MIPS_PLTGOT: 1276 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1277 dynp->d_un.d_ptr); 1278 break; 1279 1280 #endif 1281 1282 #ifdef __powerpc64__ 1283 case DT_PPC64_GLINK: 1284 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1285 break; 1286 #endif 1287 1288 case DT_FLAGS_1: 1289 if (dynp->d_un.d_val & DF_1_NOOPEN) 1290 obj->z_noopen = true; 1291 if (dynp->d_un.d_val & DF_1_ORIGIN) 1292 obj->z_origin = true; 1293 if (dynp->d_un.d_val & DF_1_GLOBAL) 1294 obj->z_global = true; 1295 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1296 obj->bind_now = true; 1297 if (dynp->d_un.d_val & DF_1_NODELETE) 1298 obj->z_nodelete = true; 1299 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1300 obj->z_loadfltr = true; 1301 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1302 obj->z_interpose = true; 1303 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1304 obj->z_nodeflib = true; 1305 break; 1306 1307 default: 1308 if (!early) { 1309 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1310 (long)dynp->d_tag); 1311 } 1312 break; 1313 } 1314 } 1315 1316 obj->traced = false; 1317 1318 if (plttype == DT_RELA) { 1319 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1320 obj->pltrel = NULL; 1321 obj->pltrelasize = obj->pltrelsize; 1322 obj->pltrelsize = 0; 1323 } 1324 1325 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1326 if (obj->valid_hash_sysv) 1327 obj->dynsymcount = obj->nchains; 1328 else if (obj->valid_hash_gnu) { 1329 obj->dynsymcount = 0; 1330 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1331 if (obj->buckets_gnu[bkt] == 0) 1332 continue; 1333 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1334 do 1335 obj->dynsymcount++; 1336 while ((*hashval++ & 1u) == 0); 1337 } 1338 obj->dynsymcount += obj->symndx_gnu; 1339 } 1340 } 1341 1342 static bool 1343 obj_resolve_origin(Obj_Entry *obj) 1344 { 1345 1346 if (obj->origin_path != NULL) 1347 return (true); 1348 obj->origin_path = xmalloc(PATH_MAX); 1349 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1350 } 1351 1352 static void 1353 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1354 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1355 { 1356 1357 if (obj->z_origin && !obj_resolve_origin(obj)) 1358 rtld_die(); 1359 1360 if (dyn_runpath != NULL) { 1361 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1362 obj->runpath = origin_subst(obj, obj->runpath); 1363 } else if (dyn_rpath != NULL) { 1364 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1365 obj->rpath = origin_subst(obj, obj->rpath); 1366 } 1367 if (dyn_soname != NULL) 1368 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1369 } 1370 1371 static void 1372 digest_dynamic(Obj_Entry *obj, int early) 1373 { 1374 const Elf_Dyn *dyn_rpath; 1375 const Elf_Dyn *dyn_soname; 1376 const Elf_Dyn *dyn_runpath; 1377 1378 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1379 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1380 } 1381 1382 /* 1383 * Process a shared object's program header. This is used only for the 1384 * main program, when the kernel has already loaded the main program 1385 * into memory before calling the dynamic linker. It creates and 1386 * returns an Obj_Entry structure. 1387 */ 1388 static Obj_Entry * 1389 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1390 { 1391 Obj_Entry *obj; 1392 const Elf_Phdr *phlimit = phdr + phnum; 1393 const Elf_Phdr *ph; 1394 Elf_Addr note_start, note_end; 1395 int nsegs = 0; 1396 1397 obj = obj_new(); 1398 for (ph = phdr; ph < phlimit; ph++) { 1399 if (ph->p_type != PT_PHDR) 1400 continue; 1401 1402 obj->phdr = phdr; 1403 obj->phsize = ph->p_memsz; 1404 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1405 break; 1406 } 1407 1408 obj->stack_flags = PF_X | PF_R | PF_W; 1409 1410 for (ph = phdr; ph < phlimit; ph++) { 1411 switch (ph->p_type) { 1412 1413 case PT_INTERP: 1414 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1415 break; 1416 1417 case PT_LOAD: 1418 if (nsegs == 0) { /* First load segment */ 1419 obj->vaddrbase = trunc_page(ph->p_vaddr); 1420 obj->mapbase = obj->vaddrbase + obj->relocbase; 1421 } else { /* Last load segment */ 1422 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1423 obj->vaddrbase; 1424 } 1425 nsegs++; 1426 break; 1427 1428 case PT_DYNAMIC: 1429 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1430 break; 1431 1432 case PT_TLS: 1433 obj->tlsindex = 1; 1434 obj->tlssize = ph->p_memsz; 1435 obj->tlsalign = ph->p_align; 1436 obj->tlsinitsize = ph->p_filesz; 1437 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1438 break; 1439 1440 case PT_GNU_STACK: 1441 obj->stack_flags = ph->p_flags; 1442 break; 1443 1444 case PT_GNU_RELRO: 1445 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1446 obj->relro_size = round_page(ph->p_memsz); 1447 break; 1448 1449 case PT_NOTE: 1450 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1451 note_end = note_start + ph->p_filesz; 1452 digest_notes(obj, note_start, note_end); 1453 break; 1454 } 1455 } 1456 if (nsegs < 1) { 1457 _rtld_error("%s: too few PT_LOAD segments", path); 1458 return NULL; 1459 } 1460 1461 obj->entry = entry; 1462 return obj; 1463 } 1464 1465 void 1466 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1467 { 1468 const Elf_Note *note; 1469 const char *note_name; 1470 uintptr_t p; 1471 1472 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1473 note = (const Elf_Note *)((const char *)(note + 1) + 1474 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1475 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1476 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1477 note->n_descsz != sizeof(int32_t)) 1478 continue; 1479 if (note->n_type != NT_FREEBSD_ABI_TAG && 1480 note->n_type != NT_FREEBSD_NOINIT_TAG) 1481 continue; 1482 note_name = (const char *)(note + 1); 1483 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1484 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1485 continue; 1486 switch (note->n_type) { 1487 case NT_FREEBSD_ABI_TAG: 1488 /* FreeBSD osrel note */ 1489 p = (uintptr_t)(note + 1); 1490 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1491 obj->osrel = *(const int32_t *)(p); 1492 dbg("note osrel %d", obj->osrel); 1493 break; 1494 case NT_FREEBSD_NOINIT_TAG: 1495 /* FreeBSD 'crt does not call init' note */ 1496 obj->crt_no_init = true; 1497 dbg("note crt_no_init"); 1498 break; 1499 } 1500 } 1501 } 1502 1503 static Obj_Entry * 1504 dlcheck(void *handle) 1505 { 1506 Obj_Entry *obj; 1507 1508 TAILQ_FOREACH(obj, &obj_list, next) { 1509 if (obj == (Obj_Entry *) handle) 1510 break; 1511 } 1512 1513 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1514 _rtld_error("Invalid shared object handle %p", handle); 1515 return NULL; 1516 } 1517 return obj; 1518 } 1519 1520 /* 1521 * If the given object is already in the donelist, return true. Otherwise 1522 * add the object to the list and return false. 1523 */ 1524 static bool 1525 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1526 { 1527 unsigned int i; 1528 1529 for (i = 0; i < dlp->num_used; i++) 1530 if (dlp->objs[i] == obj) 1531 return true; 1532 /* 1533 * Our donelist allocation should always be sufficient. But if 1534 * our threads locking isn't working properly, more shared objects 1535 * could have been loaded since we allocated the list. That should 1536 * never happen, but we'll handle it properly just in case it does. 1537 */ 1538 if (dlp->num_used < dlp->num_alloc) 1539 dlp->objs[dlp->num_used++] = obj; 1540 return false; 1541 } 1542 1543 /* 1544 * Hash function for symbol table lookup. Don't even think about changing 1545 * this. It is specified by the System V ABI. 1546 */ 1547 unsigned long 1548 elf_hash(const char *name) 1549 { 1550 const unsigned char *p = (const unsigned char *) name; 1551 unsigned long h = 0; 1552 unsigned long g; 1553 1554 while (*p != '\0') { 1555 h = (h << 4) + *p++; 1556 if ((g = h & 0xf0000000) != 0) 1557 h ^= g >> 24; 1558 h &= ~g; 1559 } 1560 return h; 1561 } 1562 1563 /* 1564 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1565 * unsigned in case it's implemented with a wider type. 1566 */ 1567 static uint32_t 1568 gnu_hash(const char *s) 1569 { 1570 uint32_t h; 1571 unsigned char c; 1572 1573 h = 5381; 1574 for (c = *s; c != '\0'; c = *++s) 1575 h = h * 33 + c; 1576 return (h & 0xffffffff); 1577 } 1578 1579 1580 /* 1581 * Find the library with the given name, and return its full pathname. 1582 * The returned string is dynamically allocated. Generates an error 1583 * message and returns NULL if the library cannot be found. 1584 * 1585 * If the second argument is non-NULL, then it refers to an already- 1586 * loaded shared object, whose library search path will be searched. 1587 * 1588 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1589 * descriptor (which is close-on-exec) will be passed out via the third 1590 * argument. 1591 * 1592 * The search order is: 1593 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1594 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1595 * LD_LIBRARY_PATH 1596 * DT_RUNPATH in the referencing file 1597 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1598 * from list) 1599 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1600 * 1601 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1602 */ 1603 static char * 1604 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1605 { 1606 char *pathname, *refobj_path; 1607 const char *name; 1608 bool nodeflib, objgiven; 1609 1610 objgiven = refobj != NULL; 1611 1612 if (libmap_disable || !objgiven || 1613 (name = lm_find(refobj->path, xname)) == NULL) 1614 name = xname; 1615 1616 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1617 if (name[0] != '/' && !trust) { 1618 _rtld_error("Absolute pathname required " 1619 "for shared object \"%s\"", name); 1620 return (NULL); 1621 } 1622 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1623 __DECONST(char *, name))); 1624 } 1625 1626 dbg(" Searching for \"%s\"", name); 1627 refobj_path = objgiven ? refobj->path : NULL; 1628 1629 /* 1630 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1631 * back to pre-conforming behaviour if user requested so with 1632 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1633 * nodeflib. 1634 */ 1635 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1636 pathname = search_library_path(name, ld_library_path, 1637 refobj_path, fdp); 1638 if (pathname != NULL) 1639 return (pathname); 1640 if (refobj != NULL) { 1641 pathname = search_library_path(name, refobj->rpath, 1642 refobj_path, fdp); 1643 if (pathname != NULL) 1644 return (pathname); 1645 } 1646 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1647 if (pathname != NULL) 1648 return (pathname); 1649 pathname = search_library_path(name, gethints(false), 1650 refobj_path, fdp); 1651 if (pathname != NULL) 1652 return (pathname); 1653 pathname = search_library_path(name, ld_standard_library_path, 1654 refobj_path, fdp); 1655 if (pathname != NULL) 1656 return (pathname); 1657 } else { 1658 nodeflib = objgiven ? refobj->z_nodeflib : false; 1659 if (objgiven) { 1660 pathname = search_library_path(name, refobj->rpath, 1661 refobj->path, fdp); 1662 if (pathname != NULL) 1663 return (pathname); 1664 } 1665 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1666 pathname = search_library_path(name, obj_main->rpath, 1667 refobj_path, fdp); 1668 if (pathname != NULL) 1669 return (pathname); 1670 } 1671 pathname = search_library_path(name, ld_library_path, 1672 refobj_path, fdp); 1673 if (pathname != NULL) 1674 return (pathname); 1675 if (objgiven) { 1676 pathname = search_library_path(name, refobj->runpath, 1677 refobj_path, fdp); 1678 if (pathname != NULL) 1679 return (pathname); 1680 } 1681 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1682 if (pathname != NULL) 1683 return (pathname); 1684 pathname = search_library_path(name, gethints(nodeflib), 1685 refobj_path, fdp); 1686 if (pathname != NULL) 1687 return (pathname); 1688 if (objgiven && !nodeflib) { 1689 pathname = search_library_path(name, 1690 ld_standard_library_path, refobj_path, fdp); 1691 if (pathname != NULL) 1692 return (pathname); 1693 } 1694 } 1695 1696 if (objgiven && refobj->path != NULL) { 1697 _rtld_error("Shared object \"%s\" not found, " 1698 "required by \"%s\"", name, basename(refobj->path)); 1699 } else { 1700 _rtld_error("Shared object \"%s\" not found", name); 1701 } 1702 return (NULL); 1703 } 1704 1705 /* 1706 * Given a symbol number in a referencing object, find the corresponding 1707 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1708 * no definition was found. Returns a pointer to the Obj_Entry of the 1709 * defining object via the reference parameter DEFOBJ_OUT. 1710 */ 1711 const Elf_Sym * 1712 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1713 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1714 RtldLockState *lockstate) 1715 { 1716 const Elf_Sym *ref; 1717 const Elf_Sym *def; 1718 const Obj_Entry *defobj; 1719 const Ver_Entry *ve; 1720 SymLook req; 1721 const char *name; 1722 int res; 1723 1724 /* 1725 * If we have already found this symbol, get the information from 1726 * the cache. 1727 */ 1728 if (symnum >= refobj->dynsymcount) 1729 return NULL; /* Bad object */ 1730 if (cache != NULL && cache[symnum].sym != NULL) { 1731 *defobj_out = cache[symnum].obj; 1732 return cache[symnum].sym; 1733 } 1734 1735 ref = refobj->symtab + symnum; 1736 name = refobj->strtab + ref->st_name; 1737 def = NULL; 1738 defobj = NULL; 1739 ve = NULL; 1740 1741 /* 1742 * We don't have to do a full scale lookup if the symbol is local. 1743 * We know it will bind to the instance in this load module; to 1744 * which we already have a pointer (ie ref). By not doing a lookup, 1745 * we not only improve performance, but it also avoids unresolvable 1746 * symbols when local symbols are not in the hash table. This has 1747 * been seen with the ia64 toolchain. 1748 */ 1749 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1750 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1751 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1752 symnum); 1753 } 1754 symlook_init(&req, name); 1755 req.flags = flags; 1756 ve = req.ventry = fetch_ventry(refobj, symnum); 1757 req.lockstate = lockstate; 1758 res = symlook_default(&req, refobj); 1759 if (res == 0) { 1760 def = req.sym_out; 1761 defobj = req.defobj_out; 1762 } 1763 } else { 1764 def = ref; 1765 defobj = refobj; 1766 } 1767 1768 /* 1769 * If we found no definition and the reference is weak, treat the 1770 * symbol as having the value zero. 1771 */ 1772 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1773 def = &sym_zero; 1774 defobj = obj_main; 1775 } 1776 1777 if (def != NULL) { 1778 *defobj_out = defobj; 1779 /* Record the information in the cache to avoid subsequent lookups. */ 1780 if (cache != NULL) { 1781 cache[symnum].sym = def; 1782 cache[symnum].obj = defobj; 1783 } 1784 } else { 1785 if (refobj != &obj_rtld) 1786 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1787 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1788 } 1789 return def; 1790 } 1791 1792 /* 1793 * Return the search path from the ldconfig hints file, reading it if 1794 * necessary. If nostdlib is true, then the default search paths are 1795 * not added to result. 1796 * 1797 * Returns NULL if there are problems with the hints file, 1798 * or if the search path there is empty. 1799 */ 1800 static const char * 1801 gethints(bool nostdlib) 1802 { 1803 static char *filtered_path; 1804 static const char *hints; 1805 static struct elfhints_hdr hdr; 1806 struct fill_search_info_args sargs, hargs; 1807 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1808 struct dl_serpath *SLPpath, *hintpath; 1809 char *p; 1810 struct stat hint_stat; 1811 unsigned int SLPndx, hintndx, fndx, fcount; 1812 int fd; 1813 size_t flen; 1814 uint32_t dl; 1815 bool skip; 1816 1817 /* First call, read the hints file */ 1818 if (hints == NULL) { 1819 /* Keep from trying again in case the hints file is bad. */ 1820 hints = ""; 1821 1822 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1823 return (NULL); 1824 1825 /* 1826 * Check of hdr.dirlistlen value against type limit 1827 * intends to pacify static analyzers. Further 1828 * paranoia leads to checks that dirlist is fully 1829 * contained in the file range. 1830 */ 1831 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1832 hdr.magic != ELFHINTS_MAGIC || 1833 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1834 fstat(fd, &hint_stat) == -1) { 1835 cleanup1: 1836 close(fd); 1837 hdr.dirlistlen = 0; 1838 return (NULL); 1839 } 1840 dl = hdr.strtab; 1841 if (dl + hdr.dirlist < dl) 1842 goto cleanup1; 1843 dl += hdr.dirlist; 1844 if (dl + hdr.dirlistlen < dl) 1845 goto cleanup1; 1846 dl += hdr.dirlistlen; 1847 if (dl > hint_stat.st_size) 1848 goto cleanup1; 1849 p = xmalloc(hdr.dirlistlen + 1); 1850 if (pread(fd, p, hdr.dirlistlen + 1, 1851 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1852 p[hdr.dirlistlen] != '\0') { 1853 free(p); 1854 goto cleanup1; 1855 } 1856 hints = p; 1857 close(fd); 1858 } 1859 1860 /* 1861 * If caller agreed to receive list which includes the default 1862 * paths, we are done. Otherwise, if we still did not 1863 * calculated filtered result, do it now. 1864 */ 1865 if (!nostdlib) 1866 return (hints[0] != '\0' ? hints : NULL); 1867 if (filtered_path != NULL) 1868 goto filt_ret; 1869 1870 /* 1871 * Obtain the list of all configured search paths, and the 1872 * list of the default paths. 1873 * 1874 * First estimate the size of the results. 1875 */ 1876 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1877 smeta.dls_cnt = 0; 1878 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1879 hmeta.dls_cnt = 0; 1880 1881 sargs.request = RTLD_DI_SERINFOSIZE; 1882 sargs.serinfo = &smeta; 1883 hargs.request = RTLD_DI_SERINFOSIZE; 1884 hargs.serinfo = &hmeta; 1885 1886 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1887 &sargs); 1888 path_enumerate(hints, fill_search_info, NULL, &hargs); 1889 1890 SLPinfo = xmalloc(smeta.dls_size); 1891 hintinfo = xmalloc(hmeta.dls_size); 1892 1893 /* 1894 * Next fetch both sets of paths. 1895 */ 1896 sargs.request = RTLD_DI_SERINFO; 1897 sargs.serinfo = SLPinfo; 1898 sargs.serpath = &SLPinfo->dls_serpath[0]; 1899 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1900 1901 hargs.request = RTLD_DI_SERINFO; 1902 hargs.serinfo = hintinfo; 1903 hargs.serpath = &hintinfo->dls_serpath[0]; 1904 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1905 1906 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1907 &sargs); 1908 path_enumerate(hints, fill_search_info, NULL, &hargs); 1909 1910 /* 1911 * Now calculate the difference between two sets, by excluding 1912 * standard paths from the full set. 1913 */ 1914 fndx = 0; 1915 fcount = 0; 1916 filtered_path = xmalloc(hdr.dirlistlen + 1); 1917 hintpath = &hintinfo->dls_serpath[0]; 1918 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1919 skip = false; 1920 SLPpath = &SLPinfo->dls_serpath[0]; 1921 /* 1922 * Check each standard path against current. 1923 */ 1924 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1925 /* matched, skip the path */ 1926 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1927 skip = true; 1928 break; 1929 } 1930 } 1931 if (skip) 1932 continue; 1933 /* 1934 * Not matched against any standard path, add the path 1935 * to result. Separate consequtive paths with ':'. 1936 */ 1937 if (fcount > 0) { 1938 filtered_path[fndx] = ':'; 1939 fndx++; 1940 } 1941 fcount++; 1942 flen = strlen(hintpath->dls_name); 1943 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1944 fndx += flen; 1945 } 1946 filtered_path[fndx] = '\0'; 1947 1948 free(SLPinfo); 1949 free(hintinfo); 1950 1951 filt_ret: 1952 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1953 } 1954 1955 static void 1956 init_dag(Obj_Entry *root) 1957 { 1958 const Needed_Entry *needed; 1959 const Objlist_Entry *elm; 1960 DoneList donelist; 1961 1962 if (root->dag_inited) 1963 return; 1964 donelist_init(&donelist); 1965 1966 /* Root object belongs to own DAG. */ 1967 objlist_push_tail(&root->dldags, root); 1968 objlist_push_tail(&root->dagmembers, root); 1969 donelist_check(&donelist, root); 1970 1971 /* 1972 * Add dependencies of root object to DAG in breadth order 1973 * by exploiting the fact that each new object get added 1974 * to the tail of the dagmembers list. 1975 */ 1976 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1977 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1978 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1979 continue; 1980 objlist_push_tail(&needed->obj->dldags, root); 1981 objlist_push_tail(&root->dagmembers, needed->obj); 1982 } 1983 } 1984 root->dag_inited = true; 1985 } 1986 1987 static void 1988 init_marker(Obj_Entry *marker) 1989 { 1990 1991 bzero(marker, sizeof(*marker)); 1992 marker->marker = true; 1993 } 1994 1995 Obj_Entry * 1996 globallist_curr(const Obj_Entry *obj) 1997 { 1998 1999 for (;;) { 2000 if (obj == NULL) 2001 return (NULL); 2002 if (!obj->marker) 2003 return (__DECONST(Obj_Entry *, obj)); 2004 obj = TAILQ_PREV(obj, obj_entry_q, next); 2005 } 2006 } 2007 2008 Obj_Entry * 2009 globallist_next(const Obj_Entry *obj) 2010 { 2011 2012 for (;;) { 2013 obj = TAILQ_NEXT(obj, next); 2014 if (obj == NULL) 2015 return (NULL); 2016 if (!obj->marker) 2017 return (__DECONST(Obj_Entry *, obj)); 2018 } 2019 } 2020 2021 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2022 static void 2023 hold_object(Obj_Entry *obj) 2024 { 2025 2026 obj->holdcount++; 2027 } 2028 2029 static void 2030 unhold_object(Obj_Entry *obj) 2031 { 2032 2033 assert(obj->holdcount > 0); 2034 if (--obj->holdcount == 0 && obj->unholdfree) 2035 release_object(obj); 2036 } 2037 2038 static void 2039 process_z(Obj_Entry *root) 2040 { 2041 const Objlist_Entry *elm; 2042 Obj_Entry *obj; 2043 2044 /* 2045 * Walk over object DAG and process every dependent object 2046 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2047 * to grow their own DAG. 2048 * 2049 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2050 * symlook_global() to work. 2051 * 2052 * For DF_1_NODELETE, the DAG should have its reference upped. 2053 */ 2054 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2055 obj = elm->obj; 2056 if (obj == NULL) 2057 continue; 2058 if (obj->z_nodelete && !obj->ref_nodel) { 2059 dbg("obj %s -z nodelete", obj->path); 2060 init_dag(obj); 2061 ref_dag(obj); 2062 obj->ref_nodel = true; 2063 } 2064 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2065 dbg("obj %s -z global", obj->path); 2066 objlist_push_tail(&list_global, obj); 2067 init_dag(obj); 2068 } 2069 } 2070 } 2071 /* 2072 * Initialize the dynamic linker. The argument is the address at which 2073 * the dynamic linker has been mapped into memory. The primary task of 2074 * this function is to relocate the dynamic linker. 2075 */ 2076 static void 2077 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2078 { 2079 Obj_Entry objtmp; /* Temporary rtld object */ 2080 const Elf_Ehdr *ehdr; 2081 const Elf_Dyn *dyn_rpath; 2082 const Elf_Dyn *dyn_soname; 2083 const Elf_Dyn *dyn_runpath; 2084 2085 #ifdef RTLD_INIT_PAGESIZES_EARLY 2086 /* The page size is required by the dynamic memory allocator. */ 2087 init_pagesizes(aux_info); 2088 #endif 2089 2090 /* 2091 * Conjure up an Obj_Entry structure for the dynamic linker. 2092 * 2093 * The "path" member can't be initialized yet because string constants 2094 * cannot yet be accessed. Below we will set it correctly. 2095 */ 2096 memset(&objtmp, 0, sizeof(objtmp)); 2097 objtmp.path = NULL; 2098 objtmp.rtld = true; 2099 objtmp.mapbase = mapbase; 2100 #ifdef PIC 2101 objtmp.relocbase = mapbase; 2102 #endif 2103 2104 objtmp.dynamic = rtld_dynamic(&objtmp); 2105 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2106 assert(objtmp.needed == NULL); 2107 #if !defined(__mips__) 2108 /* MIPS has a bogus DT_TEXTREL. */ 2109 assert(!objtmp.textrel); 2110 #endif 2111 /* 2112 * Temporarily put the dynamic linker entry into the object list, so 2113 * that symbols can be found. 2114 */ 2115 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2116 2117 ehdr = (Elf_Ehdr *)mapbase; 2118 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2119 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2120 2121 /* Initialize the object list. */ 2122 TAILQ_INIT(&obj_list); 2123 2124 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2125 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2126 2127 #ifndef RTLD_INIT_PAGESIZES_EARLY 2128 /* The page size is required by the dynamic memory allocator. */ 2129 init_pagesizes(aux_info); 2130 #endif 2131 2132 if (aux_info[AT_OSRELDATE] != NULL) 2133 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2134 2135 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2136 2137 /* Replace the path with a dynamically allocated copy. */ 2138 obj_rtld.path = xstrdup(ld_path_rtld); 2139 2140 r_debug.r_brk = r_debug_state; 2141 r_debug.r_state = RT_CONSISTENT; 2142 } 2143 2144 /* 2145 * Retrieve the array of supported page sizes. The kernel provides the page 2146 * sizes in increasing order. 2147 */ 2148 static void 2149 init_pagesizes(Elf_Auxinfo **aux_info) 2150 { 2151 static size_t psa[MAXPAGESIZES]; 2152 int mib[2]; 2153 size_t len, size; 2154 2155 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2156 NULL) { 2157 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2158 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2159 } else { 2160 len = 2; 2161 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2162 size = sizeof(psa); 2163 else { 2164 /* As a fallback, retrieve the base page size. */ 2165 size = sizeof(psa[0]); 2166 if (aux_info[AT_PAGESZ] != NULL) { 2167 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2168 goto psa_filled; 2169 } else { 2170 mib[0] = CTL_HW; 2171 mib[1] = HW_PAGESIZE; 2172 len = 2; 2173 } 2174 } 2175 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2176 _rtld_error("sysctl for hw.pagesize(s) failed"); 2177 rtld_die(); 2178 } 2179 psa_filled: 2180 pagesizes = psa; 2181 } 2182 npagesizes = size / sizeof(pagesizes[0]); 2183 /* Discard any invalid entries at the end of the array. */ 2184 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2185 npagesizes--; 2186 } 2187 2188 /* 2189 * Add the init functions from a needed object list (and its recursive 2190 * needed objects) to "list". This is not used directly; it is a helper 2191 * function for initlist_add_objects(). The write lock must be held 2192 * when this function is called. 2193 */ 2194 static void 2195 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2196 { 2197 /* Recursively process the successor needed objects. */ 2198 if (needed->next != NULL) 2199 initlist_add_neededs(needed->next, list); 2200 2201 /* Process the current needed object. */ 2202 if (needed->obj != NULL) 2203 initlist_add_objects(needed->obj, needed->obj, list); 2204 } 2205 2206 /* 2207 * Scan all of the DAGs rooted in the range of objects from "obj" to 2208 * "tail" and add their init functions to "list". This recurses over 2209 * the DAGs and ensure the proper init ordering such that each object's 2210 * needed libraries are initialized before the object itself. At the 2211 * same time, this function adds the objects to the global finalization 2212 * list "list_fini" in the opposite order. The write lock must be 2213 * held when this function is called. 2214 */ 2215 static void 2216 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2217 { 2218 Obj_Entry *nobj; 2219 2220 if (obj->init_scanned || obj->init_done) 2221 return; 2222 obj->init_scanned = true; 2223 2224 /* Recursively process the successor objects. */ 2225 nobj = globallist_next(obj); 2226 if (nobj != NULL && obj != tail) 2227 initlist_add_objects(nobj, tail, list); 2228 2229 /* Recursively process the needed objects. */ 2230 if (obj->needed != NULL) 2231 initlist_add_neededs(obj->needed, list); 2232 if (obj->needed_filtees != NULL) 2233 initlist_add_neededs(obj->needed_filtees, list); 2234 if (obj->needed_aux_filtees != NULL) 2235 initlist_add_neededs(obj->needed_aux_filtees, list); 2236 2237 /* Add the object to the init list. */ 2238 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2239 obj->init_array != (Elf_Addr)NULL) 2240 objlist_push_tail(list, obj); 2241 2242 /* Add the object to the global fini list in the reverse order. */ 2243 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2244 && !obj->on_fini_list) { 2245 objlist_push_head(&list_fini, obj); 2246 obj->on_fini_list = true; 2247 } 2248 } 2249 2250 #ifndef FPTR_TARGET 2251 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2252 #endif 2253 2254 static void 2255 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2256 { 2257 Needed_Entry *needed, *needed1; 2258 2259 for (needed = n; needed != NULL; needed = needed->next) { 2260 if (needed->obj != NULL) { 2261 dlclose_locked(needed->obj, lockstate); 2262 needed->obj = NULL; 2263 } 2264 } 2265 for (needed = n; needed != NULL; needed = needed1) { 2266 needed1 = needed->next; 2267 free(needed); 2268 } 2269 } 2270 2271 static void 2272 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2273 { 2274 2275 free_needed_filtees(obj->needed_filtees, lockstate); 2276 obj->needed_filtees = NULL; 2277 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2278 obj->needed_aux_filtees = NULL; 2279 obj->filtees_loaded = false; 2280 } 2281 2282 static void 2283 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2284 RtldLockState *lockstate) 2285 { 2286 2287 for (; needed != NULL; needed = needed->next) { 2288 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2289 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2290 RTLD_LOCAL, lockstate); 2291 } 2292 } 2293 2294 static void 2295 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2296 { 2297 2298 lock_restart_for_upgrade(lockstate); 2299 if (!obj->filtees_loaded) { 2300 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2301 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2302 obj->filtees_loaded = true; 2303 } 2304 } 2305 2306 static int 2307 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2308 { 2309 Obj_Entry *obj1; 2310 2311 for (; needed != NULL; needed = needed->next) { 2312 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2313 flags & ~RTLD_LO_NOLOAD); 2314 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2315 return (-1); 2316 } 2317 return (0); 2318 } 2319 2320 /* 2321 * Given a shared object, traverse its list of needed objects, and load 2322 * each of them. Returns 0 on success. Generates an error message and 2323 * returns -1 on failure. 2324 */ 2325 static int 2326 load_needed_objects(Obj_Entry *first, int flags) 2327 { 2328 Obj_Entry *obj; 2329 2330 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2331 if (obj->marker) 2332 continue; 2333 if (process_needed(obj, obj->needed, flags) == -1) 2334 return (-1); 2335 } 2336 return (0); 2337 } 2338 2339 static int 2340 load_preload_objects(void) 2341 { 2342 char *p = ld_preload; 2343 Obj_Entry *obj; 2344 static const char delim[] = " \t:;"; 2345 2346 if (p == NULL) 2347 return 0; 2348 2349 p += strspn(p, delim); 2350 while (*p != '\0') { 2351 size_t len = strcspn(p, delim); 2352 char savech; 2353 2354 savech = p[len]; 2355 p[len] = '\0'; 2356 obj = load_object(p, -1, NULL, 0); 2357 if (obj == NULL) 2358 return -1; /* XXX - cleanup */ 2359 obj->z_interpose = true; 2360 p[len] = savech; 2361 p += len; 2362 p += strspn(p, delim); 2363 } 2364 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2365 return 0; 2366 } 2367 2368 static const char * 2369 printable_path(const char *path) 2370 { 2371 2372 return (path == NULL ? "<unknown>" : path); 2373 } 2374 2375 /* 2376 * Load a shared object into memory, if it is not already loaded. The 2377 * object may be specified by name or by user-supplied file descriptor 2378 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2379 * duplicate is. 2380 * 2381 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2382 * on failure. 2383 */ 2384 static Obj_Entry * 2385 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2386 { 2387 Obj_Entry *obj; 2388 int fd; 2389 struct stat sb; 2390 char *path; 2391 2392 fd = -1; 2393 if (name != NULL) { 2394 TAILQ_FOREACH(obj, &obj_list, next) { 2395 if (obj->marker || obj->doomed) 2396 continue; 2397 if (object_match_name(obj, name)) 2398 return (obj); 2399 } 2400 2401 path = find_library(name, refobj, &fd); 2402 if (path == NULL) 2403 return (NULL); 2404 } else 2405 path = NULL; 2406 2407 if (fd >= 0) { 2408 /* 2409 * search_library_pathfds() opens a fresh file descriptor for the 2410 * library, so there is no need to dup(). 2411 */ 2412 } else if (fd_u == -1) { 2413 /* 2414 * If we didn't find a match by pathname, or the name is not 2415 * supplied, open the file and check again by device and inode. 2416 * This avoids false mismatches caused by multiple links or ".." 2417 * in pathnames. 2418 * 2419 * To avoid a race, we open the file and use fstat() rather than 2420 * using stat(). 2421 */ 2422 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2423 _rtld_error("Cannot open \"%s\"", path); 2424 free(path); 2425 return (NULL); 2426 } 2427 } else { 2428 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2429 if (fd == -1) { 2430 _rtld_error("Cannot dup fd"); 2431 free(path); 2432 return (NULL); 2433 } 2434 } 2435 if (fstat(fd, &sb) == -1) { 2436 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2437 close(fd); 2438 free(path); 2439 return NULL; 2440 } 2441 TAILQ_FOREACH(obj, &obj_list, next) { 2442 if (obj->marker || obj->doomed) 2443 continue; 2444 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2445 break; 2446 } 2447 if (obj != NULL && name != NULL) { 2448 object_add_name(obj, name); 2449 free(path); 2450 close(fd); 2451 return obj; 2452 } 2453 if (flags & RTLD_LO_NOLOAD) { 2454 free(path); 2455 close(fd); 2456 return (NULL); 2457 } 2458 2459 /* First use of this object, so we must map it in */ 2460 obj = do_load_object(fd, name, path, &sb, flags); 2461 if (obj == NULL) 2462 free(path); 2463 close(fd); 2464 2465 return obj; 2466 } 2467 2468 static Obj_Entry * 2469 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2470 int flags) 2471 { 2472 Obj_Entry *obj; 2473 struct statfs fs; 2474 2475 /* 2476 * but first, make sure that environment variables haven't been 2477 * used to circumvent the noexec flag on a filesystem. 2478 */ 2479 if (dangerous_ld_env) { 2480 if (fstatfs(fd, &fs) != 0) { 2481 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2482 return NULL; 2483 } 2484 if (fs.f_flags & MNT_NOEXEC) { 2485 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2486 return NULL; 2487 } 2488 } 2489 dbg("loading \"%s\"", printable_path(path)); 2490 obj = map_object(fd, printable_path(path), sbp); 2491 if (obj == NULL) 2492 return NULL; 2493 2494 /* 2495 * If DT_SONAME is present in the object, digest_dynamic2 already 2496 * added it to the object names. 2497 */ 2498 if (name != NULL) 2499 object_add_name(obj, name); 2500 obj->path = path; 2501 digest_dynamic(obj, 0); 2502 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2503 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2504 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2505 RTLD_LO_DLOPEN) { 2506 dbg("refusing to load non-loadable \"%s\"", obj->path); 2507 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2508 munmap(obj->mapbase, obj->mapsize); 2509 obj_free(obj); 2510 return (NULL); 2511 } 2512 2513 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2514 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2515 obj_count++; 2516 obj_loads++; 2517 linkmap_add(obj); /* for GDB & dlinfo() */ 2518 max_stack_flags |= obj->stack_flags; 2519 2520 dbg(" %p .. %p: %s", obj->mapbase, 2521 obj->mapbase + obj->mapsize - 1, obj->path); 2522 if (obj->textrel) 2523 dbg(" WARNING: %s has impure text", obj->path); 2524 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2525 obj->path); 2526 2527 return obj; 2528 } 2529 2530 static Obj_Entry * 2531 obj_from_addr(const void *addr) 2532 { 2533 Obj_Entry *obj; 2534 2535 TAILQ_FOREACH(obj, &obj_list, next) { 2536 if (obj->marker) 2537 continue; 2538 if (addr < (void *) obj->mapbase) 2539 continue; 2540 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2541 return obj; 2542 } 2543 return NULL; 2544 } 2545 2546 static void 2547 preinit_main(void) 2548 { 2549 Elf_Addr *preinit_addr; 2550 int index; 2551 2552 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2553 if (preinit_addr == NULL) 2554 return; 2555 2556 for (index = 0; index < obj_main->preinit_array_num; index++) { 2557 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2558 dbg("calling preinit function for %s at %p", obj_main->path, 2559 (void *)preinit_addr[index]); 2560 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2561 0, 0, obj_main->path); 2562 call_init_pointer(obj_main, preinit_addr[index]); 2563 } 2564 } 2565 } 2566 2567 /* 2568 * Call the finalization functions for each of the objects in "list" 2569 * belonging to the DAG of "root" and referenced once. If NULL "root" 2570 * is specified, every finalization function will be called regardless 2571 * of the reference count and the list elements won't be freed. All of 2572 * the objects are expected to have non-NULL fini functions. 2573 */ 2574 static void 2575 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2576 { 2577 Objlist_Entry *elm; 2578 char *saved_msg; 2579 Elf_Addr *fini_addr; 2580 int index; 2581 2582 assert(root == NULL || root->refcount == 1); 2583 2584 if (root != NULL) 2585 root->doomed = true; 2586 2587 /* 2588 * Preserve the current error message since a fini function might 2589 * call into the dynamic linker and overwrite it. 2590 */ 2591 saved_msg = errmsg_save(); 2592 do { 2593 STAILQ_FOREACH(elm, list, link) { 2594 if (root != NULL && (elm->obj->refcount != 1 || 2595 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2596 continue; 2597 /* Remove object from fini list to prevent recursive invocation. */ 2598 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2599 /* Ensure that new references cannot be acquired. */ 2600 elm->obj->doomed = true; 2601 2602 hold_object(elm->obj); 2603 lock_release(rtld_bind_lock, lockstate); 2604 /* 2605 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2606 * When this happens, DT_FINI_ARRAY is processed first. 2607 */ 2608 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2609 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2610 for (index = elm->obj->fini_array_num - 1; index >= 0; 2611 index--) { 2612 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2613 dbg("calling fini function for %s at %p", 2614 elm->obj->path, (void *)fini_addr[index]); 2615 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2616 (void *)fini_addr[index], 0, 0, elm->obj->path); 2617 call_initfini_pointer(elm->obj, fini_addr[index]); 2618 } 2619 } 2620 } 2621 if (elm->obj->fini != (Elf_Addr)NULL) { 2622 dbg("calling fini function for %s at %p", elm->obj->path, 2623 (void *)elm->obj->fini); 2624 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2625 0, 0, elm->obj->path); 2626 call_initfini_pointer(elm->obj, elm->obj->fini); 2627 } 2628 wlock_acquire(rtld_bind_lock, lockstate); 2629 unhold_object(elm->obj); 2630 /* No need to free anything if process is going down. */ 2631 if (root != NULL) 2632 free(elm); 2633 /* 2634 * We must restart the list traversal after every fini call 2635 * because a dlclose() call from the fini function or from 2636 * another thread might have modified the reference counts. 2637 */ 2638 break; 2639 } 2640 } while (elm != NULL); 2641 errmsg_restore(saved_msg); 2642 } 2643 2644 /* 2645 * Call the initialization functions for each of the objects in 2646 * "list". All of the objects are expected to have non-NULL init 2647 * functions. 2648 */ 2649 static void 2650 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2651 { 2652 Objlist_Entry *elm; 2653 Obj_Entry *obj; 2654 char *saved_msg; 2655 Elf_Addr *init_addr; 2656 int index; 2657 2658 /* 2659 * Clean init_scanned flag so that objects can be rechecked and 2660 * possibly initialized earlier if any of vectors called below 2661 * cause the change by using dlopen. 2662 */ 2663 TAILQ_FOREACH(obj, &obj_list, next) { 2664 if (obj->marker) 2665 continue; 2666 obj->init_scanned = false; 2667 } 2668 2669 /* 2670 * Preserve the current error message since an init function might 2671 * call into the dynamic linker and overwrite it. 2672 */ 2673 saved_msg = errmsg_save(); 2674 STAILQ_FOREACH(elm, list, link) { 2675 if (elm->obj->init_done) /* Initialized early. */ 2676 continue; 2677 /* 2678 * Race: other thread might try to use this object before current 2679 * one completes the initialization. Not much can be done here 2680 * without better locking. 2681 */ 2682 elm->obj->init_done = true; 2683 hold_object(elm->obj); 2684 lock_release(rtld_bind_lock, lockstate); 2685 2686 /* 2687 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2688 * When this happens, DT_INIT is processed first. 2689 */ 2690 if (elm->obj->init != (Elf_Addr)NULL) { 2691 dbg("calling init function for %s at %p", elm->obj->path, 2692 (void *)elm->obj->init); 2693 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2694 0, 0, elm->obj->path); 2695 call_initfini_pointer(elm->obj, elm->obj->init); 2696 } 2697 init_addr = (Elf_Addr *)elm->obj->init_array; 2698 if (init_addr != NULL) { 2699 for (index = 0; index < elm->obj->init_array_num; index++) { 2700 if (init_addr[index] != 0 && init_addr[index] != 1) { 2701 dbg("calling init function for %s at %p", elm->obj->path, 2702 (void *)init_addr[index]); 2703 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2704 (void *)init_addr[index], 0, 0, elm->obj->path); 2705 call_init_pointer(elm->obj, init_addr[index]); 2706 } 2707 } 2708 } 2709 wlock_acquire(rtld_bind_lock, lockstate); 2710 unhold_object(elm->obj); 2711 } 2712 errmsg_restore(saved_msg); 2713 } 2714 2715 static void 2716 objlist_clear(Objlist *list) 2717 { 2718 Objlist_Entry *elm; 2719 2720 while (!STAILQ_EMPTY(list)) { 2721 elm = STAILQ_FIRST(list); 2722 STAILQ_REMOVE_HEAD(list, link); 2723 free(elm); 2724 } 2725 } 2726 2727 static Objlist_Entry * 2728 objlist_find(Objlist *list, const Obj_Entry *obj) 2729 { 2730 Objlist_Entry *elm; 2731 2732 STAILQ_FOREACH(elm, list, link) 2733 if (elm->obj == obj) 2734 return elm; 2735 return NULL; 2736 } 2737 2738 static void 2739 objlist_init(Objlist *list) 2740 { 2741 STAILQ_INIT(list); 2742 } 2743 2744 static void 2745 objlist_push_head(Objlist *list, Obj_Entry *obj) 2746 { 2747 Objlist_Entry *elm; 2748 2749 elm = NEW(Objlist_Entry); 2750 elm->obj = obj; 2751 STAILQ_INSERT_HEAD(list, elm, link); 2752 } 2753 2754 static void 2755 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2756 { 2757 Objlist_Entry *elm; 2758 2759 elm = NEW(Objlist_Entry); 2760 elm->obj = obj; 2761 STAILQ_INSERT_TAIL(list, elm, link); 2762 } 2763 2764 static void 2765 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2766 { 2767 Objlist_Entry *elm, *listelm; 2768 2769 STAILQ_FOREACH(listelm, list, link) { 2770 if (listelm->obj == listobj) 2771 break; 2772 } 2773 elm = NEW(Objlist_Entry); 2774 elm->obj = obj; 2775 if (listelm != NULL) 2776 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2777 else 2778 STAILQ_INSERT_TAIL(list, elm, link); 2779 } 2780 2781 static void 2782 objlist_remove(Objlist *list, Obj_Entry *obj) 2783 { 2784 Objlist_Entry *elm; 2785 2786 if ((elm = objlist_find(list, obj)) != NULL) { 2787 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2788 free(elm); 2789 } 2790 } 2791 2792 /* 2793 * Relocate dag rooted in the specified object. 2794 * Returns 0 on success, or -1 on failure. 2795 */ 2796 2797 static int 2798 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2799 int flags, RtldLockState *lockstate) 2800 { 2801 Objlist_Entry *elm; 2802 int error; 2803 2804 error = 0; 2805 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2806 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2807 lockstate); 2808 if (error == -1) 2809 break; 2810 } 2811 return (error); 2812 } 2813 2814 /* 2815 * Prepare for, or clean after, relocating an object marked with 2816 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2817 * segments are remapped read-write. After relocations are done, the 2818 * segment's permissions are returned back to the modes specified in 2819 * the phdrs. If any relocation happened, or always for wired 2820 * program, COW is triggered. 2821 */ 2822 static int 2823 reloc_textrel_prot(Obj_Entry *obj, bool before) 2824 { 2825 const Elf_Phdr *ph; 2826 void *base; 2827 size_t l, sz; 2828 int prot; 2829 2830 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2831 l--, ph++) { 2832 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2833 continue; 2834 base = obj->relocbase + trunc_page(ph->p_vaddr); 2835 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2836 trunc_page(ph->p_vaddr); 2837 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2838 if (mprotect(base, sz, prot) == -1) { 2839 _rtld_error("%s: Cannot write-%sable text segment: %s", 2840 obj->path, before ? "en" : "dis", 2841 rtld_strerror(errno)); 2842 return (-1); 2843 } 2844 } 2845 return (0); 2846 } 2847 2848 /* 2849 * Relocate single object. 2850 * Returns 0 on success, or -1 on failure. 2851 */ 2852 static int 2853 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2854 int flags, RtldLockState *lockstate) 2855 { 2856 2857 if (obj->relocated) 2858 return (0); 2859 obj->relocated = true; 2860 if (obj != rtldobj) 2861 dbg("relocating \"%s\"", obj->path); 2862 2863 if (obj->symtab == NULL || obj->strtab == NULL || 2864 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2865 _rtld_error("%s: Shared object has no run-time symbol table", 2866 obj->path); 2867 return (-1); 2868 } 2869 2870 /* There are relocations to the write-protected text segment. */ 2871 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2872 return (-1); 2873 2874 /* Process the non-PLT non-IFUNC relocations. */ 2875 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2876 return (-1); 2877 2878 /* Re-protected the text segment. */ 2879 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2880 return (-1); 2881 2882 /* Set the special PLT or GOT entries. */ 2883 init_pltgot(obj); 2884 2885 /* Process the PLT relocations. */ 2886 if (reloc_plt(obj) == -1) 2887 return (-1); 2888 /* Relocate the jump slots if we are doing immediate binding. */ 2889 if (obj->bind_now || bind_now) { 2890 if (reloc_jmpslots(obj, flags, lockstate) == -1 || 2891 resolve_object_ifunc(obj, true, flags, lockstate) == -1) 2892 return (-1); 2893 } 2894 2895 /* 2896 * Process the non-PLT IFUNC relocations. The relocations are 2897 * processed in two phases, because IFUNC resolvers may 2898 * reference other symbols, which must be readily processed 2899 * before resolvers are called. 2900 */ 2901 if (obj->non_plt_gnu_ifunc && 2902 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2903 return (-1); 2904 2905 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2906 return (-1); 2907 2908 /* 2909 * Set up the magic number and version in the Obj_Entry. These 2910 * were checked in the crt1.o from the original ElfKit, so we 2911 * set them for backward compatibility. 2912 */ 2913 obj->magic = RTLD_MAGIC; 2914 obj->version = RTLD_VERSION; 2915 2916 return (0); 2917 } 2918 2919 /* 2920 * Relocate newly-loaded shared objects. The argument is a pointer to 2921 * the Obj_Entry for the first such object. All objects from the first 2922 * to the end of the list of objects are relocated. Returns 0 on success, 2923 * or -1 on failure. 2924 */ 2925 static int 2926 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2927 int flags, RtldLockState *lockstate) 2928 { 2929 Obj_Entry *obj; 2930 int error; 2931 2932 for (error = 0, obj = first; obj != NULL; 2933 obj = TAILQ_NEXT(obj, next)) { 2934 if (obj->marker) 2935 continue; 2936 error = relocate_object(obj, bind_now, rtldobj, flags, 2937 lockstate); 2938 if (error == -1) 2939 break; 2940 } 2941 return (error); 2942 } 2943 2944 /* 2945 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2946 * referencing STT_GNU_IFUNC symbols is postponed till the other 2947 * relocations are done. The indirect functions specified as 2948 * ifunc are allowed to call other symbols, so we need to have 2949 * objects relocated before asking for resolution from indirects. 2950 * 2951 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2952 * instead of the usual lazy handling of PLT slots. It is 2953 * consistent with how GNU does it. 2954 */ 2955 static int 2956 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2957 RtldLockState *lockstate) 2958 { 2959 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2960 return (-1); 2961 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2962 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2963 return (-1); 2964 return (0); 2965 } 2966 2967 static int 2968 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2969 RtldLockState *lockstate) 2970 { 2971 Obj_Entry *obj; 2972 2973 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2974 if (obj->marker) 2975 continue; 2976 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2977 return (-1); 2978 } 2979 return (0); 2980 } 2981 2982 static int 2983 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2984 RtldLockState *lockstate) 2985 { 2986 Objlist_Entry *elm; 2987 2988 STAILQ_FOREACH(elm, list, link) { 2989 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2990 lockstate) == -1) 2991 return (-1); 2992 } 2993 return (0); 2994 } 2995 2996 /* 2997 * Cleanup procedure. It will be called (by the atexit mechanism) just 2998 * before the process exits. 2999 */ 3000 static void 3001 rtld_exit(void) 3002 { 3003 RtldLockState lockstate; 3004 3005 wlock_acquire(rtld_bind_lock, &lockstate); 3006 dbg("rtld_exit()"); 3007 objlist_call_fini(&list_fini, NULL, &lockstate); 3008 /* No need to remove the items from the list, since we are exiting. */ 3009 if (!libmap_disable) 3010 lm_fini(); 3011 lock_release(rtld_bind_lock, &lockstate); 3012 } 3013 3014 /* 3015 * Iterate over a search path, translate each element, and invoke the 3016 * callback on the result. 3017 */ 3018 static void * 3019 path_enumerate(const char *path, path_enum_proc callback, 3020 const char *refobj_path, void *arg) 3021 { 3022 const char *trans; 3023 if (path == NULL) 3024 return (NULL); 3025 3026 path += strspn(path, ":;"); 3027 while (*path != '\0') { 3028 size_t len; 3029 char *res; 3030 3031 len = strcspn(path, ":;"); 3032 trans = lm_findn(refobj_path, path, len); 3033 if (trans) 3034 res = callback(trans, strlen(trans), arg); 3035 else 3036 res = callback(path, len, arg); 3037 3038 if (res != NULL) 3039 return (res); 3040 3041 path += len; 3042 path += strspn(path, ":;"); 3043 } 3044 3045 return (NULL); 3046 } 3047 3048 struct try_library_args { 3049 const char *name; 3050 size_t namelen; 3051 char *buffer; 3052 size_t buflen; 3053 int fd; 3054 }; 3055 3056 static void * 3057 try_library_path(const char *dir, size_t dirlen, void *param) 3058 { 3059 struct try_library_args *arg; 3060 int fd; 3061 3062 arg = param; 3063 if (*dir == '/' || trust) { 3064 char *pathname; 3065 3066 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3067 return (NULL); 3068 3069 pathname = arg->buffer; 3070 strncpy(pathname, dir, dirlen); 3071 pathname[dirlen] = '/'; 3072 strcpy(pathname + dirlen + 1, arg->name); 3073 3074 dbg(" Trying \"%s\"", pathname); 3075 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3076 if (fd >= 0) { 3077 dbg(" Opened \"%s\", fd %d", pathname, fd); 3078 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3079 strcpy(pathname, arg->buffer); 3080 arg->fd = fd; 3081 return (pathname); 3082 } else { 3083 dbg(" Failed to open \"%s\": %s", 3084 pathname, rtld_strerror(errno)); 3085 } 3086 } 3087 return (NULL); 3088 } 3089 3090 static char * 3091 search_library_path(const char *name, const char *path, 3092 const char *refobj_path, int *fdp) 3093 { 3094 char *p; 3095 struct try_library_args arg; 3096 3097 if (path == NULL) 3098 return NULL; 3099 3100 arg.name = name; 3101 arg.namelen = strlen(name); 3102 arg.buffer = xmalloc(PATH_MAX); 3103 arg.buflen = PATH_MAX; 3104 arg.fd = -1; 3105 3106 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3107 *fdp = arg.fd; 3108 3109 free(arg.buffer); 3110 3111 return (p); 3112 } 3113 3114 3115 /* 3116 * Finds the library with the given name using the directory descriptors 3117 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3118 * 3119 * Returns a freshly-opened close-on-exec file descriptor for the library, 3120 * or -1 if the library cannot be found. 3121 */ 3122 static char * 3123 search_library_pathfds(const char *name, const char *path, int *fdp) 3124 { 3125 char *envcopy, *fdstr, *found, *last_token; 3126 size_t len; 3127 int dirfd, fd; 3128 3129 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3130 3131 /* Don't load from user-specified libdirs into setuid binaries. */ 3132 if (!trust) 3133 return (NULL); 3134 3135 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3136 if (path == NULL) 3137 return (NULL); 3138 3139 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3140 if (name[0] == '/') { 3141 dbg("Absolute path (%s) passed to %s", name, __func__); 3142 return (NULL); 3143 } 3144 3145 /* 3146 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3147 * copy of the path, as strtok_r rewrites separator tokens 3148 * with '\0'. 3149 */ 3150 found = NULL; 3151 envcopy = xstrdup(path); 3152 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3153 fdstr = strtok_r(NULL, ":", &last_token)) { 3154 dirfd = parse_integer(fdstr); 3155 if (dirfd < 0) { 3156 _rtld_error("failed to parse directory FD: '%s'", 3157 fdstr); 3158 break; 3159 } 3160 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3161 if (fd >= 0) { 3162 *fdp = fd; 3163 len = strlen(fdstr) + strlen(name) + 3; 3164 found = xmalloc(len); 3165 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3166 _rtld_error("error generating '%d/%s'", 3167 dirfd, name); 3168 rtld_die(); 3169 } 3170 dbg("open('%s') => %d", found, fd); 3171 break; 3172 } 3173 } 3174 free(envcopy); 3175 3176 return (found); 3177 } 3178 3179 3180 int 3181 dlclose(void *handle) 3182 { 3183 RtldLockState lockstate; 3184 int error; 3185 3186 wlock_acquire(rtld_bind_lock, &lockstate); 3187 error = dlclose_locked(handle, &lockstate); 3188 lock_release(rtld_bind_lock, &lockstate); 3189 return (error); 3190 } 3191 3192 static int 3193 dlclose_locked(void *handle, RtldLockState *lockstate) 3194 { 3195 Obj_Entry *root; 3196 3197 root = dlcheck(handle); 3198 if (root == NULL) 3199 return -1; 3200 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3201 root->path); 3202 3203 /* Unreference the object and its dependencies. */ 3204 root->dl_refcount--; 3205 3206 if (root->refcount == 1) { 3207 /* 3208 * The object will be no longer referenced, so we must unload it. 3209 * First, call the fini functions. 3210 */ 3211 objlist_call_fini(&list_fini, root, lockstate); 3212 3213 unref_dag(root); 3214 3215 /* Finish cleaning up the newly-unreferenced objects. */ 3216 GDB_STATE(RT_DELETE,&root->linkmap); 3217 unload_object(root, lockstate); 3218 GDB_STATE(RT_CONSISTENT,NULL); 3219 } else 3220 unref_dag(root); 3221 3222 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3223 return 0; 3224 } 3225 3226 char * 3227 dlerror(void) 3228 { 3229 char *msg = error_message; 3230 error_message = NULL; 3231 return msg; 3232 } 3233 3234 /* 3235 * This function is deprecated and has no effect. 3236 */ 3237 void 3238 dllockinit(void *context, 3239 void *(*_lock_create)(void *context) __unused, 3240 void (*_rlock_acquire)(void *lock) __unused, 3241 void (*_wlock_acquire)(void *lock) __unused, 3242 void (*_lock_release)(void *lock) __unused, 3243 void (*_lock_destroy)(void *lock) __unused, 3244 void (*context_destroy)(void *context)) 3245 { 3246 static void *cur_context; 3247 static void (*cur_context_destroy)(void *); 3248 3249 /* Just destroy the context from the previous call, if necessary. */ 3250 if (cur_context_destroy != NULL) 3251 cur_context_destroy(cur_context); 3252 cur_context = context; 3253 cur_context_destroy = context_destroy; 3254 } 3255 3256 void * 3257 dlopen(const char *name, int mode) 3258 { 3259 3260 return (rtld_dlopen(name, -1, mode)); 3261 } 3262 3263 void * 3264 fdlopen(int fd, int mode) 3265 { 3266 3267 return (rtld_dlopen(NULL, fd, mode)); 3268 } 3269 3270 static void * 3271 rtld_dlopen(const char *name, int fd, int mode) 3272 { 3273 RtldLockState lockstate; 3274 int lo_flags; 3275 3276 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3277 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3278 if (ld_tracing != NULL) { 3279 rlock_acquire(rtld_bind_lock, &lockstate); 3280 if (sigsetjmp(lockstate.env, 0) != 0) 3281 lock_upgrade(rtld_bind_lock, &lockstate); 3282 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3283 lock_release(rtld_bind_lock, &lockstate); 3284 } 3285 lo_flags = RTLD_LO_DLOPEN; 3286 if (mode & RTLD_NODELETE) 3287 lo_flags |= RTLD_LO_NODELETE; 3288 if (mode & RTLD_NOLOAD) 3289 lo_flags |= RTLD_LO_NOLOAD; 3290 if (ld_tracing != NULL) 3291 lo_flags |= RTLD_LO_TRACE; 3292 3293 return (dlopen_object(name, fd, obj_main, lo_flags, 3294 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3295 } 3296 3297 static void 3298 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3299 { 3300 3301 obj->dl_refcount--; 3302 unref_dag(obj); 3303 if (obj->refcount == 0) 3304 unload_object(obj, lockstate); 3305 } 3306 3307 static Obj_Entry * 3308 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3309 int mode, RtldLockState *lockstate) 3310 { 3311 Obj_Entry *old_obj_tail; 3312 Obj_Entry *obj; 3313 Objlist initlist; 3314 RtldLockState mlockstate; 3315 int result; 3316 3317 objlist_init(&initlist); 3318 3319 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3320 wlock_acquire(rtld_bind_lock, &mlockstate); 3321 lockstate = &mlockstate; 3322 } 3323 GDB_STATE(RT_ADD,NULL); 3324 3325 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3326 obj = NULL; 3327 if (name == NULL && fd == -1) { 3328 obj = obj_main; 3329 obj->refcount++; 3330 } else { 3331 obj = load_object(name, fd, refobj, lo_flags); 3332 } 3333 3334 if (obj) { 3335 obj->dl_refcount++; 3336 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3337 objlist_push_tail(&list_global, obj); 3338 if (globallist_next(old_obj_tail) != NULL) { 3339 /* We loaded something new. */ 3340 assert(globallist_next(old_obj_tail) == obj); 3341 result = load_needed_objects(obj, 3342 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3343 init_dag(obj); 3344 ref_dag(obj); 3345 if (result != -1) 3346 result = rtld_verify_versions(&obj->dagmembers); 3347 if (result != -1 && ld_tracing) 3348 goto trace; 3349 if (result == -1 || relocate_object_dag(obj, 3350 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3351 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3352 lockstate) == -1) { 3353 dlopen_cleanup(obj, lockstate); 3354 obj = NULL; 3355 } else if (lo_flags & RTLD_LO_EARLY) { 3356 /* 3357 * Do not call the init functions for early loaded 3358 * filtees. The image is still not initialized enough 3359 * for them to work. 3360 * 3361 * Our object is found by the global object list and 3362 * will be ordered among all init calls done right 3363 * before transferring control to main. 3364 */ 3365 } else { 3366 /* Make list of init functions to call. */ 3367 initlist_add_objects(obj, obj, &initlist); 3368 } 3369 /* 3370 * Process all no_delete or global objects here, given 3371 * them own DAGs to prevent their dependencies from being 3372 * unloaded. This has to be done after we have loaded all 3373 * of the dependencies, so that we do not miss any. 3374 */ 3375 if (obj != NULL) 3376 process_z(obj); 3377 } else { 3378 /* 3379 * Bump the reference counts for objects on this DAG. If 3380 * this is the first dlopen() call for the object that was 3381 * already loaded as a dependency, initialize the dag 3382 * starting at it. 3383 */ 3384 init_dag(obj); 3385 ref_dag(obj); 3386 3387 if ((lo_flags & RTLD_LO_TRACE) != 0) 3388 goto trace; 3389 } 3390 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3391 obj->z_nodelete) && !obj->ref_nodel) { 3392 dbg("obj %s nodelete", obj->path); 3393 ref_dag(obj); 3394 obj->z_nodelete = obj->ref_nodel = true; 3395 } 3396 } 3397 3398 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3399 name); 3400 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3401 3402 if (!(lo_flags & RTLD_LO_EARLY)) { 3403 map_stacks_exec(lockstate); 3404 } 3405 3406 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3407 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3408 lockstate) == -1) { 3409 objlist_clear(&initlist); 3410 dlopen_cleanup(obj, lockstate); 3411 if (lockstate == &mlockstate) 3412 lock_release(rtld_bind_lock, lockstate); 3413 return (NULL); 3414 } 3415 3416 if (!(lo_flags & RTLD_LO_EARLY)) { 3417 /* Call the init functions. */ 3418 objlist_call_init(&initlist, lockstate); 3419 } 3420 objlist_clear(&initlist); 3421 if (lockstate == &mlockstate) 3422 lock_release(rtld_bind_lock, lockstate); 3423 return obj; 3424 trace: 3425 trace_loaded_objects(obj); 3426 if (lockstate == &mlockstate) 3427 lock_release(rtld_bind_lock, lockstate); 3428 exit(0); 3429 } 3430 3431 static void * 3432 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3433 int flags) 3434 { 3435 DoneList donelist; 3436 const Obj_Entry *obj, *defobj; 3437 const Elf_Sym *def; 3438 SymLook req; 3439 RtldLockState lockstate; 3440 tls_index ti; 3441 void *sym; 3442 int res; 3443 3444 def = NULL; 3445 defobj = NULL; 3446 symlook_init(&req, name); 3447 req.ventry = ve; 3448 req.flags = flags | SYMLOOK_IN_PLT; 3449 req.lockstate = &lockstate; 3450 3451 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3452 rlock_acquire(rtld_bind_lock, &lockstate); 3453 if (sigsetjmp(lockstate.env, 0) != 0) 3454 lock_upgrade(rtld_bind_lock, &lockstate); 3455 if (handle == NULL || handle == RTLD_NEXT || 3456 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3457 3458 if ((obj = obj_from_addr(retaddr)) == NULL) { 3459 _rtld_error("Cannot determine caller's shared object"); 3460 lock_release(rtld_bind_lock, &lockstate); 3461 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3462 return NULL; 3463 } 3464 if (handle == NULL) { /* Just the caller's shared object. */ 3465 res = symlook_obj(&req, obj); 3466 if (res == 0) { 3467 def = req.sym_out; 3468 defobj = req.defobj_out; 3469 } 3470 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3471 handle == RTLD_SELF) { /* ... caller included */ 3472 if (handle == RTLD_NEXT) 3473 obj = globallist_next(obj); 3474 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3475 if (obj->marker) 3476 continue; 3477 res = symlook_obj(&req, obj); 3478 if (res == 0) { 3479 if (def == NULL || 3480 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3481 def = req.sym_out; 3482 defobj = req.defobj_out; 3483 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3484 break; 3485 } 3486 } 3487 } 3488 /* 3489 * Search the dynamic linker itself, and possibly resolve the 3490 * symbol from there. This is how the application links to 3491 * dynamic linker services such as dlopen. 3492 */ 3493 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3494 res = symlook_obj(&req, &obj_rtld); 3495 if (res == 0) { 3496 def = req.sym_out; 3497 defobj = req.defobj_out; 3498 } 3499 } 3500 } else { 3501 assert(handle == RTLD_DEFAULT); 3502 res = symlook_default(&req, obj); 3503 if (res == 0) { 3504 defobj = req.defobj_out; 3505 def = req.sym_out; 3506 } 3507 } 3508 } else { 3509 if ((obj = dlcheck(handle)) == NULL) { 3510 lock_release(rtld_bind_lock, &lockstate); 3511 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3512 return NULL; 3513 } 3514 3515 donelist_init(&donelist); 3516 if (obj->mainprog) { 3517 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3518 res = symlook_global(&req, &donelist); 3519 if (res == 0) { 3520 def = req.sym_out; 3521 defobj = req.defobj_out; 3522 } 3523 /* 3524 * Search the dynamic linker itself, and possibly resolve the 3525 * symbol from there. This is how the application links to 3526 * dynamic linker services such as dlopen. 3527 */ 3528 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3529 res = symlook_obj(&req, &obj_rtld); 3530 if (res == 0) { 3531 def = req.sym_out; 3532 defobj = req.defobj_out; 3533 } 3534 } 3535 } 3536 else { 3537 /* Search the whole DAG rooted at the given object. */ 3538 res = symlook_list(&req, &obj->dagmembers, &donelist); 3539 if (res == 0) { 3540 def = req.sym_out; 3541 defobj = req.defobj_out; 3542 } 3543 } 3544 } 3545 3546 if (def != NULL) { 3547 lock_release(rtld_bind_lock, &lockstate); 3548 3549 /* 3550 * The value required by the caller is derived from the value 3551 * of the symbol. this is simply the relocated value of the 3552 * symbol. 3553 */ 3554 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3555 sym = make_function_pointer(def, defobj); 3556 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3557 sym = rtld_resolve_ifunc(defobj, def); 3558 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3559 ti.ti_module = defobj->tlsindex; 3560 ti.ti_offset = def->st_value; 3561 sym = __tls_get_addr(&ti); 3562 } else 3563 sym = defobj->relocbase + def->st_value; 3564 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3565 return (sym); 3566 } 3567 3568 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3569 ve != NULL ? ve->name : ""); 3570 lock_release(rtld_bind_lock, &lockstate); 3571 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3572 return NULL; 3573 } 3574 3575 void * 3576 dlsym(void *handle, const char *name) 3577 { 3578 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3579 SYMLOOK_DLSYM); 3580 } 3581 3582 dlfunc_t 3583 dlfunc(void *handle, const char *name) 3584 { 3585 union { 3586 void *d; 3587 dlfunc_t f; 3588 } rv; 3589 3590 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3591 SYMLOOK_DLSYM); 3592 return (rv.f); 3593 } 3594 3595 void * 3596 dlvsym(void *handle, const char *name, const char *version) 3597 { 3598 Ver_Entry ventry; 3599 3600 ventry.name = version; 3601 ventry.file = NULL; 3602 ventry.hash = elf_hash(version); 3603 ventry.flags= 0; 3604 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3605 SYMLOOK_DLSYM); 3606 } 3607 3608 int 3609 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3610 { 3611 const Obj_Entry *obj; 3612 RtldLockState lockstate; 3613 3614 rlock_acquire(rtld_bind_lock, &lockstate); 3615 obj = obj_from_addr(addr); 3616 if (obj == NULL) { 3617 _rtld_error("No shared object contains address"); 3618 lock_release(rtld_bind_lock, &lockstate); 3619 return (0); 3620 } 3621 rtld_fill_dl_phdr_info(obj, phdr_info); 3622 lock_release(rtld_bind_lock, &lockstate); 3623 return (1); 3624 } 3625 3626 int 3627 dladdr(const void *addr, Dl_info *info) 3628 { 3629 const Obj_Entry *obj; 3630 const Elf_Sym *def; 3631 void *symbol_addr; 3632 unsigned long symoffset; 3633 RtldLockState lockstate; 3634 3635 rlock_acquire(rtld_bind_lock, &lockstate); 3636 obj = obj_from_addr(addr); 3637 if (obj == NULL) { 3638 _rtld_error("No shared object contains address"); 3639 lock_release(rtld_bind_lock, &lockstate); 3640 return 0; 3641 } 3642 info->dli_fname = obj->path; 3643 info->dli_fbase = obj->mapbase; 3644 info->dli_saddr = (void *)0; 3645 info->dli_sname = NULL; 3646 3647 /* 3648 * Walk the symbol list looking for the symbol whose address is 3649 * closest to the address sent in. 3650 */ 3651 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3652 def = obj->symtab + symoffset; 3653 3654 /* 3655 * For skip the symbol if st_shndx is either SHN_UNDEF or 3656 * SHN_COMMON. 3657 */ 3658 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3659 continue; 3660 3661 /* 3662 * If the symbol is greater than the specified address, or if it 3663 * is further away from addr than the current nearest symbol, 3664 * then reject it. 3665 */ 3666 symbol_addr = obj->relocbase + def->st_value; 3667 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3668 continue; 3669 3670 /* Update our idea of the nearest symbol. */ 3671 info->dli_sname = obj->strtab + def->st_name; 3672 info->dli_saddr = symbol_addr; 3673 3674 /* Exact match? */ 3675 if (info->dli_saddr == addr) 3676 break; 3677 } 3678 lock_release(rtld_bind_lock, &lockstate); 3679 return 1; 3680 } 3681 3682 int 3683 dlinfo(void *handle, int request, void *p) 3684 { 3685 const Obj_Entry *obj; 3686 RtldLockState lockstate; 3687 int error; 3688 3689 rlock_acquire(rtld_bind_lock, &lockstate); 3690 3691 if (handle == NULL || handle == RTLD_SELF) { 3692 void *retaddr; 3693 3694 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3695 if ((obj = obj_from_addr(retaddr)) == NULL) 3696 _rtld_error("Cannot determine caller's shared object"); 3697 } else 3698 obj = dlcheck(handle); 3699 3700 if (obj == NULL) { 3701 lock_release(rtld_bind_lock, &lockstate); 3702 return (-1); 3703 } 3704 3705 error = 0; 3706 switch (request) { 3707 case RTLD_DI_LINKMAP: 3708 *((struct link_map const **)p) = &obj->linkmap; 3709 break; 3710 case RTLD_DI_ORIGIN: 3711 error = rtld_dirname(obj->path, p); 3712 break; 3713 3714 case RTLD_DI_SERINFOSIZE: 3715 case RTLD_DI_SERINFO: 3716 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3717 break; 3718 3719 default: 3720 _rtld_error("Invalid request %d passed to dlinfo()", request); 3721 error = -1; 3722 } 3723 3724 lock_release(rtld_bind_lock, &lockstate); 3725 3726 return (error); 3727 } 3728 3729 static void 3730 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3731 { 3732 3733 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3734 phdr_info->dlpi_name = obj->path; 3735 phdr_info->dlpi_phdr = obj->phdr; 3736 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3737 phdr_info->dlpi_tls_modid = obj->tlsindex; 3738 phdr_info->dlpi_tls_data = obj->tlsinit; 3739 phdr_info->dlpi_adds = obj_loads; 3740 phdr_info->dlpi_subs = obj_loads - obj_count; 3741 } 3742 3743 int 3744 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3745 { 3746 struct dl_phdr_info phdr_info; 3747 Obj_Entry *obj, marker; 3748 RtldLockState bind_lockstate, phdr_lockstate; 3749 int error; 3750 3751 init_marker(&marker); 3752 error = 0; 3753 3754 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3755 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3756 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3757 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3758 rtld_fill_dl_phdr_info(obj, &phdr_info); 3759 hold_object(obj); 3760 lock_release(rtld_bind_lock, &bind_lockstate); 3761 3762 error = callback(&phdr_info, sizeof phdr_info, param); 3763 3764 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3765 unhold_object(obj); 3766 obj = globallist_next(&marker); 3767 TAILQ_REMOVE(&obj_list, &marker, next); 3768 if (error != 0) { 3769 lock_release(rtld_bind_lock, &bind_lockstate); 3770 lock_release(rtld_phdr_lock, &phdr_lockstate); 3771 return (error); 3772 } 3773 } 3774 3775 if (error == 0) { 3776 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3777 lock_release(rtld_bind_lock, &bind_lockstate); 3778 error = callback(&phdr_info, sizeof(phdr_info), param); 3779 } 3780 lock_release(rtld_phdr_lock, &phdr_lockstate); 3781 return (error); 3782 } 3783 3784 static void * 3785 fill_search_info(const char *dir, size_t dirlen, void *param) 3786 { 3787 struct fill_search_info_args *arg; 3788 3789 arg = param; 3790 3791 if (arg->request == RTLD_DI_SERINFOSIZE) { 3792 arg->serinfo->dls_cnt ++; 3793 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3794 } else { 3795 struct dl_serpath *s_entry; 3796 3797 s_entry = arg->serpath; 3798 s_entry->dls_name = arg->strspace; 3799 s_entry->dls_flags = arg->flags; 3800 3801 strncpy(arg->strspace, dir, dirlen); 3802 arg->strspace[dirlen] = '\0'; 3803 3804 arg->strspace += dirlen + 1; 3805 arg->serpath++; 3806 } 3807 3808 return (NULL); 3809 } 3810 3811 static int 3812 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3813 { 3814 struct dl_serinfo _info; 3815 struct fill_search_info_args args; 3816 3817 args.request = RTLD_DI_SERINFOSIZE; 3818 args.serinfo = &_info; 3819 3820 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3821 _info.dls_cnt = 0; 3822 3823 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3824 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3825 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3826 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3827 if (!obj->z_nodeflib) 3828 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3829 3830 3831 if (request == RTLD_DI_SERINFOSIZE) { 3832 info->dls_size = _info.dls_size; 3833 info->dls_cnt = _info.dls_cnt; 3834 return (0); 3835 } 3836 3837 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3838 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3839 return (-1); 3840 } 3841 3842 args.request = RTLD_DI_SERINFO; 3843 args.serinfo = info; 3844 args.serpath = &info->dls_serpath[0]; 3845 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3846 3847 args.flags = LA_SER_RUNPATH; 3848 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3849 return (-1); 3850 3851 args.flags = LA_SER_LIBPATH; 3852 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3853 return (-1); 3854 3855 args.flags = LA_SER_RUNPATH; 3856 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3857 return (-1); 3858 3859 args.flags = LA_SER_CONFIG; 3860 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3861 != NULL) 3862 return (-1); 3863 3864 args.flags = LA_SER_DEFAULT; 3865 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3866 fill_search_info, NULL, &args) != NULL) 3867 return (-1); 3868 return (0); 3869 } 3870 3871 static int 3872 rtld_dirname(const char *path, char *bname) 3873 { 3874 const char *endp; 3875 3876 /* Empty or NULL string gets treated as "." */ 3877 if (path == NULL || *path == '\0') { 3878 bname[0] = '.'; 3879 bname[1] = '\0'; 3880 return (0); 3881 } 3882 3883 /* Strip trailing slashes */ 3884 endp = path + strlen(path) - 1; 3885 while (endp > path && *endp == '/') 3886 endp--; 3887 3888 /* Find the start of the dir */ 3889 while (endp > path && *endp != '/') 3890 endp--; 3891 3892 /* Either the dir is "/" or there are no slashes */ 3893 if (endp == path) { 3894 bname[0] = *endp == '/' ? '/' : '.'; 3895 bname[1] = '\0'; 3896 return (0); 3897 } else { 3898 do { 3899 endp--; 3900 } while (endp > path && *endp == '/'); 3901 } 3902 3903 if (endp - path + 2 > PATH_MAX) 3904 { 3905 _rtld_error("Filename is too long: %s", path); 3906 return(-1); 3907 } 3908 3909 strncpy(bname, path, endp - path + 1); 3910 bname[endp - path + 1] = '\0'; 3911 return (0); 3912 } 3913 3914 static int 3915 rtld_dirname_abs(const char *path, char *base) 3916 { 3917 char *last; 3918 3919 if (realpath(path, base) == NULL) 3920 return (-1); 3921 dbg("%s -> %s", path, base); 3922 last = strrchr(base, '/'); 3923 if (last == NULL) 3924 return (-1); 3925 if (last != base) 3926 *last = '\0'; 3927 return (0); 3928 } 3929 3930 static void 3931 linkmap_add(Obj_Entry *obj) 3932 { 3933 struct link_map *l = &obj->linkmap; 3934 struct link_map *prev; 3935 3936 obj->linkmap.l_name = obj->path; 3937 obj->linkmap.l_addr = obj->mapbase; 3938 obj->linkmap.l_ld = obj->dynamic; 3939 #ifdef __mips__ 3940 /* GDB needs load offset on MIPS to use the symbols */ 3941 obj->linkmap.l_offs = obj->relocbase; 3942 #endif 3943 3944 if (r_debug.r_map == NULL) { 3945 r_debug.r_map = l; 3946 return; 3947 } 3948 3949 /* 3950 * Scan to the end of the list, but not past the entry for the 3951 * dynamic linker, which we want to keep at the very end. 3952 */ 3953 for (prev = r_debug.r_map; 3954 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3955 prev = prev->l_next) 3956 ; 3957 3958 /* Link in the new entry. */ 3959 l->l_prev = prev; 3960 l->l_next = prev->l_next; 3961 if (l->l_next != NULL) 3962 l->l_next->l_prev = l; 3963 prev->l_next = l; 3964 } 3965 3966 static void 3967 linkmap_delete(Obj_Entry *obj) 3968 { 3969 struct link_map *l = &obj->linkmap; 3970 3971 if (l->l_prev == NULL) { 3972 if ((r_debug.r_map = l->l_next) != NULL) 3973 l->l_next->l_prev = NULL; 3974 return; 3975 } 3976 3977 if ((l->l_prev->l_next = l->l_next) != NULL) 3978 l->l_next->l_prev = l->l_prev; 3979 } 3980 3981 /* 3982 * Function for the debugger to set a breakpoint on to gain control. 3983 * 3984 * The two parameters allow the debugger to easily find and determine 3985 * what the runtime loader is doing and to whom it is doing it. 3986 * 3987 * When the loadhook trap is hit (r_debug_state, set at program 3988 * initialization), the arguments can be found on the stack: 3989 * 3990 * +8 struct link_map *m 3991 * +4 struct r_debug *rd 3992 * +0 RetAddr 3993 */ 3994 void 3995 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3996 { 3997 /* 3998 * The following is a hack to force the compiler to emit calls to 3999 * this function, even when optimizing. If the function is empty, 4000 * the compiler is not obliged to emit any code for calls to it, 4001 * even when marked __noinline. However, gdb depends on those 4002 * calls being made. 4003 */ 4004 __compiler_membar(); 4005 } 4006 4007 /* 4008 * A function called after init routines have completed. This can be used to 4009 * break before a program's entry routine is called, and can be used when 4010 * main is not available in the symbol table. 4011 */ 4012 void 4013 _r_debug_postinit(struct link_map *m __unused) 4014 { 4015 4016 /* See r_debug_state(). */ 4017 __compiler_membar(); 4018 } 4019 4020 static void 4021 release_object(Obj_Entry *obj) 4022 { 4023 4024 if (obj->holdcount > 0) { 4025 obj->unholdfree = true; 4026 return; 4027 } 4028 munmap(obj->mapbase, obj->mapsize); 4029 linkmap_delete(obj); 4030 obj_free(obj); 4031 } 4032 4033 /* 4034 * Get address of the pointer variable in the main program. 4035 * Prefer non-weak symbol over the weak one. 4036 */ 4037 static const void ** 4038 get_program_var_addr(const char *name, RtldLockState *lockstate) 4039 { 4040 SymLook req; 4041 DoneList donelist; 4042 4043 symlook_init(&req, name); 4044 req.lockstate = lockstate; 4045 donelist_init(&donelist); 4046 if (symlook_global(&req, &donelist) != 0) 4047 return (NULL); 4048 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4049 return ((const void **)make_function_pointer(req.sym_out, 4050 req.defobj_out)); 4051 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4052 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4053 else 4054 return ((const void **)(req.defobj_out->relocbase + 4055 req.sym_out->st_value)); 4056 } 4057 4058 /* 4059 * Set a pointer variable in the main program to the given value. This 4060 * is used to set key variables such as "environ" before any of the 4061 * init functions are called. 4062 */ 4063 static void 4064 set_program_var(const char *name, const void *value) 4065 { 4066 const void **addr; 4067 4068 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4069 dbg("\"%s\": *%p <-- %p", name, addr, value); 4070 *addr = value; 4071 } 4072 } 4073 4074 /* 4075 * Search the global objects, including dependencies and main object, 4076 * for the given symbol. 4077 */ 4078 static int 4079 symlook_global(SymLook *req, DoneList *donelist) 4080 { 4081 SymLook req1; 4082 const Objlist_Entry *elm; 4083 int res; 4084 4085 symlook_init_from_req(&req1, req); 4086 4087 /* Search all objects loaded at program start up. */ 4088 if (req->defobj_out == NULL || 4089 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4090 res = symlook_list(&req1, &list_main, donelist); 4091 if (res == 0 && (req->defobj_out == NULL || 4092 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4093 req->sym_out = req1.sym_out; 4094 req->defobj_out = req1.defobj_out; 4095 assert(req->defobj_out != NULL); 4096 } 4097 } 4098 4099 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4100 STAILQ_FOREACH(elm, &list_global, link) { 4101 if (req->defobj_out != NULL && 4102 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4103 break; 4104 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4105 if (res == 0 && (req->defobj_out == NULL || 4106 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4107 req->sym_out = req1.sym_out; 4108 req->defobj_out = req1.defobj_out; 4109 assert(req->defobj_out != NULL); 4110 } 4111 } 4112 4113 return (req->sym_out != NULL ? 0 : ESRCH); 4114 } 4115 4116 /* 4117 * Given a symbol name in a referencing object, find the corresponding 4118 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4119 * no definition was found. Returns a pointer to the Obj_Entry of the 4120 * defining object via the reference parameter DEFOBJ_OUT. 4121 */ 4122 static int 4123 symlook_default(SymLook *req, const Obj_Entry *refobj) 4124 { 4125 DoneList donelist; 4126 const Objlist_Entry *elm; 4127 SymLook req1; 4128 int res; 4129 4130 donelist_init(&donelist); 4131 symlook_init_from_req(&req1, req); 4132 4133 /* 4134 * Look first in the referencing object if linked symbolically, 4135 * and similarly handle protected symbols. 4136 */ 4137 res = symlook_obj(&req1, refobj); 4138 if (res == 0 && (refobj->symbolic || 4139 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4140 req->sym_out = req1.sym_out; 4141 req->defobj_out = req1.defobj_out; 4142 assert(req->defobj_out != NULL); 4143 } 4144 if (refobj->symbolic || req->defobj_out != NULL) 4145 donelist_check(&donelist, refobj); 4146 4147 symlook_global(req, &donelist); 4148 4149 /* Search all dlopened DAGs containing the referencing object. */ 4150 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4151 if (req->sym_out != NULL && 4152 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4153 break; 4154 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4155 if (res == 0 && (req->sym_out == NULL || 4156 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4157 req->sym_out = req1.sym_out; 4158 req->defobj_out = req1.defobj_out; 4159 assert(req->defobj_out != NULL); 4160 } 4161 } 4162 4163 /* 4164 * Search the dynamic linker itself, and possibly resolve the 4165 * symbol from there. This is how the application links to 4166 * dynamic linker services such as dlopen. 4167 */ 4168 if (req->sym_out == NULL || 4169 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4170 res = symlook_obj(&req1, &obj_rtld); 4171 if (res == 0) { 4172 req->sym_out = req1.sym_out; 4173 req->defobj_out = req1.defobj_out; 4174 assert(req->defobj_out != NULL); 4175 } 4176 } 4177 4178 return (req->sym_out != NULL ? 0 : ESRCH); 4179 } 4180 4181 static int 4182 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4183 { 4184 const Elf_Sym *def; 4185 const Obj_Entry *defobj; 4186 const Objlist_Entry *elm; 4187 SymLook req1; 4188 int res; 4189 4190 def = NULL; 4191 defobj = NULL; 4192 STAILQ_FOREACH(elm, objlist, link) { 4193 if (donelist_check(dlp, elm->obj)) 4194 continue; 4195 symlook_init_from_req(&req1, req); 4196 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4197 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4198 def = req1.sym_out; 4199 defobj = req1.defobj_out; 4200 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4201 break; 4202 } 4203 } 4204 } 4205 if (def != NULL) { 4206 req->sym_out = def; 4207 req->defobj_out = defobj; 4208 return (0); 4209 } 4210 return (ESRCH); 4211 } 4212 4213 /* 4214 * Search the chain of DAGS cointed to by the given Needed_Entry 4215 * for a symbol of the given name. Each DAG is scanned completely 4216 * before advancing to the next one. Returns a pointer to the symbol, 4217 * or NULL if no definition was found. 4218 */ 4219 static int 4220 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4221 { 4222 const Elf_Sym *def; 4223 const Needed_Entry *n; 4224 const Obj_Entry *defobj; 4225 SymLook req1; 4226 int res; 4227 4228 def = NULL; 4229 defobj = NULL; 4230 symlook_init_from_req(&req1, req); 4231 for (n = needed; n != NULL; n = n->next) { 4232 if (n->obj == NULL || 4233 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4234 continue; 4235 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4236 def = req1.sym_out; 4237 defobj = req1.defobj_out; 4238 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4239 break; 4240 } 4241 } 4242 if (def != NULL) { 4243 req->sym_out = def; 4244 req->defobj_out = defobj; 4245 return (0); 4246 } 4247 return (ESRCH); 4248 } 4249 4250 /* 4251 * Search the symbol table of a single shared object for a symbol of 4252 * the given name and version, if requested. Returns a pointer to the 4253 * symbol, or NULL if no definition was found. If the object is 4254 * filter, return filtered symbol from filtee. 4255 * 4256 * The symbol's hash value is passed in for efficiency reasons; that 4257 * eliminates many recomputations of the hash value. 4258 */ 4259 int 4260 symlook_obj(SymLook *req, const Obj_Entry *obj) 4261 { 4262 DoneList donelist; 4263 SymLook req1; 4264 int flags, res, mres; 4265 4266 /* 4267 * If there is at least one valid hash at this point, we prefer to 4268 * use the faster GNU version if available. 4269 */ 4270 if (obj->valid_hash_gnu) 4271 mres = symlook_obj1_gnu(req, obj); 4272 else if (obj->valid_hash_sysv) 4273 mres = symlook_obj1_sysv(req, obj); 4274 else 4275 return (EINVAL); 4276 4277 if (mres == 0) { 4278 if (obj->needed_filtees != NULL) { 4279 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4280 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4281 donelist_init(&donelist); 4282 symlook_init_from_req(&req1, req); 4283 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4284 if (res == 0) { 4285 req->sym_out = req1.sym_out; 4286 req->defobj_out = req1.defobj_out; 4287 } 4288 return (res); 4289 } 4290 if (obj->needed_aux_filtees != NULL) { 4291 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4292 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4293 donelist_init(&donelist); 4294 symlook_init_from_req(&req1, req); 4295 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4296 if (res == 0) { 4297 req->sym_out = req1.sym_out; 4298 req->defobj_out = req1.defobj_out; 4299 return (res); 4300 } 4301 } 4302 } 4303 return (mres); 4304 } 4305 4306 /* Symbol match routine common to both hash functions */ 4307 static bool 4308 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4309 const unsigned long symnum) 4310 { 4311 Elf_Versym verndx; 4312 const Elf_Sym *symp; 4313 const char *strp; 4314 4315 symp = obj->symtab + symnum; 4316 strp = obj->strtab + symp->st_name; 4317 4318 switch (ELF_ST_TYPE(symp->st_info)) { 4319 case STT_FUNC: 4320 case STT_NOTYPE: 4321 case STT_OBJECT: 4322 case STT_COMMON: 4323 case STT_GNU_IFUNC: 4324 if (symp->st_value == 0) 4325 return (false); 4326 /* fallthrough */ 4327 case STT_TLS: 4328 if (symp->st_shndx != SHN_UNDEF) 4329 break; 4330 #ifndef __mips__ 4331 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4332 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4333 break; 4334 #endif 4335 /* fallthrough */ 4336 default: 4337 return (false); 4338 } 4339 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4340 return (false); 4341 4342 if (req->ventry == NULL) { 4343 if (obj->versyms != NULL) { 4344 verndx = VER_NDX(obj->versyms[symnum]); 4345 if (verndx > obj->vernum) { 4346 _rtld_error( 4347 "%s: symbol %s references wrong version %d", 4348 obj->path, obj->strtab + symnum, verndx); 4349 return (false); 4350 } 4351 /* 4352 * If we are not called from dlsym (i.e. this 4353 * is a normal relocation from unversioned 4354 * binary), accept the symbol immediately if 4355 * it happens to have first version after this 4356 * shared object became versioned. Otherwise, 4357 * if symbol is versioned and not hidden, 4358 * remember it. If it is the only symbol with 4359 * this name exported by the shared object, it 4360 * will be returned as a match by the calling 4361 * function. If symbol is global (verndx < 2) 4362 * accept it unconditionally. 4363 */ 4364 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4365 verndx == VER_NDX_GIVEN) { 4366 result->sym_out = symp; 4367 return (true); 4368 } 4369 else if (verndx >= VER_NDX_GIVEN) { 4370 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4371 == 0) { 4372 if (result->vsymp == NULL) 4373 result->vsymp = symp; 4374 result->vcount++; 4375 } 4376 return (false); 4377 } 4378 } 4379 result->sym_out = symp; 4380 return (true); 4381 } 4382 if (obj->versyms == NULL) { 4383 if (object_match_name(obj, req->ventry->name)) { 4384 _rtld_error("%s: object %s should provide version %s " 4385 "for symbol %s", obj_rtld.path, obj->path, 4386 req->ventry->name, obj->strtab + symnum); 4387 return (false); 4388 } 4389 } else { 4390 verndx = VER_NDX(obj->versyms[symnum]); 4391 if (verndx > obj->vernum) { 4392 _rtld_error("%s: symbol %s references wrong version %d", 4393 obj->path, obj->strtab + symnum, verndx); 4394 return (false); 4395 } 4396 if (obj->vertab[verndx].hash != req->ventry->hash || 4397 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4398 /* 4399 * Version does not match. Look if this is a 4400 * global symbol and if it is not hidden. If 4401 * global symbol (verndx < 2) is available, 4402 * use it. Do not return symbol if we are 4403 * called by dlvsym, because dlvsym looks for 4404 * a specific version and default one is not 4405 * what dlvsym wants. 4406 */ 4407 if ((req->flags & SYMLOOK_DLSYM) || 4408 (verndx >= VER_NDX_GIVEN) || 4409 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4410 return (false); 4411 } 4412 } 4413 result->sym_out = symp; 4414 return (true); 4415 } 4416 4417 /* 4418 * Search for symbol using SysV hash function. 4419 * obj->buckets is known not to be NULL at this point; the test for this was 4420 * performed with the obj->valid_hash_sysv assignment. 4421 */ 4422 static int 4423 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4424 { 4425 unsigned long symnum; 4426 Sym_Match_Result matchres; 4427 4428 matchres.sym_out = NULL; 4429 matchres.vsymp = NULL; 4430 matchres.vcount = 0; 4431 4432 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4433 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4434 if (symnum >= obj->nchains) 4435 return (ESRCH); /* Bad object */ 4436 4437 if (matched_symbol(req, obj, &matchres, symnum)) { 4438 req->sym_out = matchres.sym_out; 4439 req->defobj_out = obj; 4440 return (0); 4441 } 4442 } 4443 if (matchres.vcount == 1) { 4444 req->sym_out = matchres.vsymp; 4445 req->defobj_out = obj; 4446 return (0); 4447 } 4448 return (ESRCH); 4449 } 4450 4451 /* Search for symbol using GNU hash function */ 4452 static int 4453 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4454 { 4455 Elf_Addr bloom_word; 4456 const Elf32_Word *hashval; 4457 Elf32_Word bucket; 4458 Sym_Match_Result matchres; 4459 unsigned int h1, h2; 4460 unsigned long symnum; 4461 4462 matchres.sym_out = NULL; 4463 matchres.vsymp = NULL; 4464 matchres.vcount = 0; 4465 4466 /* Pick right bitmask word from Bloom filter array */ 4467 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4468 obj->maskwords_bm_gnu]; 4469 4470 /* Calculate modulus word size of gnu hash and its derivative */ 4471 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4472 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4473 4474 /* Filter out the "definitely not in set" queries */ 4475 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4476 return (ESRCH); 4477 4478 /* Locate hash chain and corresponding value element*/ 4479 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4480 if (bucket == 0) 4481 return (ESRCH); 4482 hashval = &obj->chain_zero_gnu[bucket]; 4483 do { 4484 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4485 symnum = hashval - obj->chain_zero_gnu; 4486 if (matched_symbol(req, obj, &matchres, symnum)) { 4487 req->sym_out = matchres.sym_out; 4488 req->defobj_out = obj; 4489 return (0); 4490 } 4491 } 4492 } while ((*hashval++ & 1) == 0); 4493 if (matchres.vcount == 1) { 4494 req->sym_out = matchres.vsymp; 4495 req->defobj_out = obj; 4496 return (0); 4497 } 4498 return (ESRCH); 4499 } 4500 4501 static void 4502 trace_loaded_objects(Obj_Entry *obj) 4503 { 4504 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4505 int c; 4506 4507 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4508 main_local = ""; 4509 4510 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4511 fmt1 = "\t%o => %p (%x)\n"; 4512 4513 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4514 fmt2 = "\t%o (%x)\n"; 4515 4516 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4517 4518 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4519 Needed_Entry *needed; 4520 const char *name, *path; 4521 bool is_lib; 4522 4523 if (obj->marker) 4524 continue; 4525 if (list_containers && obj->needed != NULL) 4526 rtld_printf("%s:\n", obj->path); 4527 for (needed = obj->needed; needed; needed = needed->next) { 4528 if (needed->obj != NULL) { 4529 if (needed->obj->traced && !list_containers) 4530 continue; 4531 needed->obj->traced = true; 4532 path = needed->obj->path; 4533 } else 4534 path = "not found"; 4535 4536 name = obj->strtab + needed->name; 4537 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4538 4539 fmt = is_lib ? fmt1 : fmt2; 4540 while ((c = *fmt++) != '\0') { 4541 switch (c) { 4542 default: 4543 rtld_putchar(c); 4544 continue; 4545 case '\\': 4546 switch (c = *fmt) { 4547 case '\0': 4548 continue; 4549 case 'n': 4550 rtld_putchar('\n'); 4551 break; 4552 case 't': 4553 rtld_putchar('\t'); 4554 break; 4555 } 4556 break; 4557 case '%': 4558 switch (c = *fmt) { 4559 case '\0': 4560 continue; 4561 case '%': 4562 default: 4563 rtld_putchar(c); 4564 break; 4565 case 'A': 4566 rtld_putstr(main_local); 4567 break; 4568 case 'a': 4569 rtld_putstr(obj_main->path); 4570 break; 4571 case 'o': 4572 rtld_putstr(name); 4573 break; 4574 #if 0 4575 case 'm': 4576 rtld_printf("%d", sodp->sod_major); 4577 break; 4578 case 'n': 4579 rtld_printf("%d", sodp->sod_minor); 4580 break; 4581 #endif 4582 case 'p': 4583 rtld_putstr(path); 4584 break; 4585 case 'x': 4586 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4587 0); 4588 break; 4589 } 4590 break; 4591 } 4592 ++fmt; 4593 } 4594 } 4595 } 4596 } 4597 4598 /* 4599 * Unload a dlopened object and its dependencies from memory and from 4600 * our data structures. It is assumed that the DAG rooted in the 4601 * object has already been unreferenced, and that the object has a 4602 * reference count of 0. 4603 */ 4604 static void 4605 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4606 { 4607 Obj_Entry marker, *obj, *next; 4608 4609 assert(root->refcount == 0); 4610 4611 /* 4612 * Pass over the DAG removing unreferenced objects from 4613 * appropriate lists. 4614 */ 4615 unlink_object(root); 4616 4617 /* Unmap all objects that are no longer referenced. */ 4618 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4619 next = TAILQ_NEXT(obj, next); 4620 if (obj->marker || obj->refcount != 0) 4621 continue; 4622 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4623 obj->mapsize, 0, obj->path); 4624 dbg("unloading \"%s\"", obj->path); 4625 /* 4626 * Unlink the object now to prevent new references from 4627 * being acquired while the bind lock is dropped in 4628 * recursive dlclose() invocations. 4629 */ 4630 TAILQ_REMOVE(&obj_list, obj, next); 4631 obj_count--; 4632 4633 if (obj->filtees_loaded) { 4634 if (next != NULL) { 4635 init_marker(&marker); 4636 TAILQ_INSERT_BEFORE(next, &marker, next); 4637 unload_filtees(obj, lockstate); 4638 next = TAILQ_NEXT(&marker, next); 4639 TAILQ_REMOVE(&obj_list, &marker, next); 4640 } else 4641 unload_filtees(obj, lockstate); 4642 } 4643 release_object(obj); 4644 } 4645 } 4646 4647 static void 4648 unlink_object(Obj_Entry *root) 4649 { 4650 Objlist_Entry *elm; 4651 4652 if (root->refcount == 0) { 4653 /* Remove the object from the RTLD_GLOBAL list. */ 4654 objlist_remove(&list_global, root); 4655 4656 /* Remove the object from all objects' DAG lists. */ 4657 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4658 objlist_remove(&elm->obj->dldags, root); 4659 if (elm->obj != root) 4660 unlink_object(elm->obj); 4661 } 4662 } 4663 } 4664 4665 static void 4666 ref_dag(Obj_Entry *root) 4667 { 4668 Objlist_Entry *elm; 4669 4670 assert(root->dag_inited); 4671 STAILQ_FOREACH(elm, &root->dagmembers, link) 4672 elm->obj->refcount++; 4673 } 4674 4675 static void 4676 unref_dag(Obj_Entry *root) 4677 { 4678 Objlist_Entry *elm; 4679 4680 assert(root->dag_inited); 4681 STAILQ_FOREACH(elm, &root->dagmembers, link) 4682 elm->obj->refcount--; 4683 } 4684 4685 /* 4686 * Common code for MD __tls_get_addr(). 4687 */ 4688 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4689 static void * 4690 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4691 { 4692 Elf_Addr *newdtv, *dtv; 4693 RtldLockState lockstate; 4694 int to_copy; 4695 4696 dtv = *dtvp; 4697 /* Check dtv generation in case new modules have arrived */ 4698 if (dtv[0] != tls_dtv_generation) { 4699 wlock_acquire(rtld_bind_lock, &lockstate); 4700 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4701 to_copy = dtv[1]; 4702 if (to_copy > tls_max_index) 4703 to_copy = tls_max_index; 4704 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4705 newdtv[0] = tls_dtv_generation; 4706 newdtv[1] = tls_max_index; 4707 free(dtv); 4708 lock_release(rtld_bind_lock, &lockstate); 4709 dtv = *dtvp = newdtv; 4710 } 4711 4712 /* Dynamically allocate module TLS if necessary */ 4713 if (dtv[index + 1] == 0) { 4714 /* Signal safe, wlock will block out signals. */ 4715 wlock_acquire(rtld_bind_lock, &lockstate); 4716 if (!dtv[index + 1]) 4717 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4718 lock_release(rtld_bind_lock, &lockstate); 4719 } 4720 return ((void *)(dtv[index + 1] + offset)); 4721 } 4722 4723 void * 4724 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4725 { 4726 Elf_Addr *dtv; 4727 4728 dtv = *dtvp; 4729 /* Check dtv generation in case new modules have arrived */ 4730 if (__predict_true(dtv[0] == tls_dtv_generation && 4731 dtv[index + 1] != 0)) 4732 return ((void *)(dtv[index + 1] + offset)); 4733 return (tls_get_addr_slow(dtvp, index, offset)); 4734 } 4735 4736 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4737 defined(__powerpc__) || defined(__riscv) 4738 4739 /* 4740 * Return pointer to allocated TLS block 4741 */ 4742 static void * 4743 get_tls_block_ptr(void *tcb, size_t tcbsize) 4744 { 4745 size_t extra_size, post_size, pre_size, tls_block_size; 4746 size_t tls_init_align; 4747 4748 tls_init_align = MAX(obj_main->tlsalign, 1); 4749 4750 /* Compute fragments sizes. */ 4751 extra_size = tcbsize - TLS_TCB_SIZE; 4752 post_size = calculate_tls_post_size(tls_init_align); 4753 tls_block_size = tcbsize + post_size; 4754 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4755 4756 return ((char *)tcb - pre_size - extra_size); 4757 } 4758 4759 /* 4760 * Allocate Static TLS using the Variant I method. 4761 * 4762 * For details on the layout, see lib/libc/gen/tls.c. 4763 * 4764 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4765 * it is based on tls_last_offset, and TLS offsets here are really TCB 4766 * offsets, whereas libc's tls_static_space is just the executable's static 4767 * TLS segment. 4768 */ 4769 void * 4770 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4771 { 4772 Obj_Entry *obj; 4773 char *tls_block; 4774 Elf_Addr *dtv, **tcb; 4775 Elf_Addr addr; 4776 Elf_Addr i; 4777 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4778 size_t tls_init_align; 4779 4780 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4781 return (oldtcb); 4782 4783 assert(tcbsize >= TLS_TCB_SIZE); 4784 maxalign = MAX(tcbalign, tls_static_max_align); 4785 tls_init_align = MAX(obj_main->tlsalign, 1); 4786 4787 /* Compute fragmets sizes. */ 4788 extra_size = tcbsize - TLS_TCB_SIZE; 4789 post_size = calculate_tls_post_size(tls_init_align); 4790 tls_block_size = tcbsize + post_size; 4791 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4792 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4793 4794 /* Allocate whole TLS block */ 4795 tls_block = malloc_aligned(tls_block_size, maxalign); 4796 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4797 4798 if (oldtcb != NULL) { 4799 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4800 tls_static_space); 4801 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4802 4803 /* Adjust the DTV. */ 4804 dtv = tcb[0]; 4805 for (i = 0; i < dtv[1]; i++) { 4806 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4807 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4808 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4809 } 4810 } 4811 } else { 4812 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4813 tcb[0] = dtv; 4814 dtv[0] = tls_dtv_generation; 4815 dtv[1] = tls_max_index; 4816 4817 for (obj = globallist_curr(objs); obj != NULL; 4818 obj = globallist_next(obj)) { 4819 if (obj->tlsoffset > 0) { 4820 addr = (Elf_Addr)tcb + obj->tlsoffset; 4821 if (obj->tlsinitsize > 0) 4822 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4823 if (obj->tlssize > obj->tlsinitsize) 4824 memset((void*)(addr + obj->tlsinitsize), 0, 4825 obj->tlssize - obj->tlsinitsize); 4826 dtv[obj->tlsindex + 1] = addr; 4827 } 4828 } 4829 } 4830 4831 return (tcb); 4832 } 4833 4834 void 4835 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4836 { 4837 Elf_Addr *dtv; 4838 Elf_Addr tlsstart, tlsend; 4839 size_t post_size; 4840 size_t dtvsize, i, tls_init_align; 4841 4842 assert(tcbsize >= TLS_TCB_SIZE); 4843 tls_init_align = MAX(obj_main->tlsalign, 1); 4844 4845 /* Compute fragments sizes. */ 4846 post_size = calculate_tls_post_size(tls_init_align); 4847 4848 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4849 tlsend = (Elf_Addr)tcb + tls_static_space; 4850 4851 dtv = *(Elf_Addr **)tcb; 4852 dtvsize = dtv[1]; 4853 for (i = 0; i < dtvsize; i++) { 4854 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4855 free((void*)dtv[i+2]); 4856 } 4857 } 4858 free(dtv); 4859 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4860 } 4861 4862 #endif 4863 4864 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4865 4866 /* 4867 * Allocate Static TLS using the Variant II method. 4868 */ 4869 void * 4870 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4871 { 4872 Obj_Entry *obj; 4873 size_t size, ralign; 4874 char *tls; 4875 Elf_Addr *dtv, *olddtv; 4876 Elf_Addr segbase, oldsegbase, addr; 4877 size_t i; 4878 4879 ralign = tcbalign; 4880 if (tls_static_max_align > ralign) 4881 ralign = tls_static_max_align; 4882 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4883 4884 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4885 tls = malloc_aligned(size, ralign); 4886 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4887 4888 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4889 ((Elf_Addr*)segbase)[0] = segbase; 4890 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4891 4892 dtv[0] = tls_dtv_generation; 4893 dtv[1] = tls_max_index; 4894 4895 if (oldtls) { 4896 /* 4897 * Copy the static TLS block over whole. 4898 */ 4899 oldsegbase = (Elf_Addr) oldtls; 4900 memcpy((void *)(segbase - tls_static_space), 4901 (const void *)(oldsegbase - tls_static_space), 4902 tls_static_space); 4903 4904 /* 4905 * If any dynamic TLS blocks have been created tls_get_addr(), 4906 * move them over. 4907 */ 4908 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4909 for (i = 0; i < olddtv[1]; i++) { 4910 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4911 dtv[i+2] = olddtv[i+2]; 4912 olddtv[i+2] = 0; 4913 } 4914 } 4915 4916 /* 4917 * We assume that this block was the one we created with 4918 * allocate_initial_tls(). 4919 */ 4920 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4921 } else { 4922 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4923 if (obj->marker || obj->tlsoffset == 0) 4924 continue; 4925 addr = segbase - obj->tlsoffset; 4926 memset((void*)(addr + obj->tlsinitsize), 4927 0, obj->tlssize - obj->tlsinitsize); 4928 if (obj->tlsinit) 4929 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4930 dtv[obj->tlsindex + 1] = addr; 4931 } 4932 } 4933 4934 return (void*) segbase; 4935 } 4936 4937 void 4938 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4939 { 4940 Elf_Addr* dtv; 4941 size_t size, ralign; 4942 int dtvsize, i; 4943 Elf_Addr tlsstart, tlsend; 4944 4945 /* 4946 * Figure out the size of the initial TLS block so that we can 4947 * find stuff which ___tls_get_addr() allocated dynamically. 4948 */ 4949 ralign = tcbalign; 4950 if (tls_static_max_align > ralign) 4951 ralign = tls_static_max_align; 4952 size = round(tls_static_space, ralign); 4953 4954 dtv = ((Elf_Addr**)tls)[1]; 4955 dtvsize = dtv[1]; 4956 tlsend = (Elf_Addr) tls; 4957 tlsstart = tlsend - size; 4958 for (i = 0; i < dtvsize; i++) { 4959 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4960 free_aligned((void *)dtv[i + 2]); 4961 } 4962 } 4963 4964 free_aligned((void *)tlsstart); 4965 free((void*) dtv); 4966 } 4967 4968 #endif 4969 4970 /* 4971 * Allocate TLS block for module with given index. 4972 */ 4973 void * 4974 allocate_module_tls(int index) 4975 { 4976 Obj_Entry* obj; 4977 char* p; 4978 4979 TAILQ_FOREACH(obj, &obj_list, next) { 4980 if (obj->marker) 4981 continue; 4982 if (obj->tlsindex == index) 4983 break; 4984 } 4985 if (!obj) { 4986 _rtld_error("Can't find module with TLS index %d", index); 4987 rtld_die(); 4988 } 4989 4990 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4991 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4992 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4993 4994 return p; 4995 } 4996 4997 bool 4998 allocate_tls_offset(Obj_Entry *obj) 4999 { 5000 size_t off; 5001 5002 if (obj->tls_done) 5003 return true; 5004 5005 if (obj->tlssize == 0) { 5006 obj->tls_done = true; 5007 return true; 5008 } 5009 5010 if (tls_last_offset == 0) 5011 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5012 else 5013 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5014 obj->tlssize, obj->tlsalign); 5015 5016 /* 5017 * If we have already fixed the size of the static TLS block, we 5018 * must stay within that size. When allocating the static TLS, we 5019 * leave a small amount of space spare to be used for dynamically 5020 * loading modules which use static TLS. 5021 */ 5022 if (tls_static_space != 0) { 5023 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5024 return false; 5025 } else if (obj->tlsalign > tls_static_max_align) { 5026 tls_static_max_align = obj->tlsalign; 5027 } 5028 5029 tls_last_offset = obj->tlsoffset = off; 5030 tls_last_size = obj->tlssize; 5031 obj->tls_done = true; 5032 5033 return true; 5034 } 5035 5036 void 5037 free_tls_offset(Obj_Entry *obj) 5038 { 5039 5040 /* 5041 * If we were the last thing to allocate out of the static TLS 5042 * block, we give our space back to the 'allocator'. This is a 5043 * simplistic workaround to allow libGL.so.1 to be loaded and 5044 * unloaded multiple times. 5045 */ 5046 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5047 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5048 tls_last_offset -= obj->tlssize; 5049 tls_last_size = 0; 5050 } 5051 } 5052 5053 void * 5054 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5055 { 5056 void *ret; 5057 RtldLockState lockstate; 5058 5059 wlock_acquire(rtld_bind_lock, &lockstate); 5060 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5061 tcbsize, tcbalign); 5062 lock_release(rtld_bind_lock, &lockstate); 5063 return (ret); 5064 } 5065 5066 void 5067 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5068 { 5069 RtldLockState lockstate; 5070 5071 wlock_acquire(rtld_bind_lock, &lockstate); 5072 free_tls(tcb, tcbsize, tcbalign); 5073 lock_release(rtld_bind_lock, &lockstate); 5074 } 5075 5076 static void 5077 object_add_name(Obj_Entry *obj, const char *name) 5078 { 5079 Name_Entry *entry; 5080 size_t len; 5081 5082 len = strlen(name); 5083 entry = malloc(sizeof(Name_Entry) + len); 5084 5085 if (entry != NULL) { 5086 strcpy(entry->name, name); 5087 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5088 } 5089 } 5090 5091 static int 5092 object_match_name(const Obj_Entry *obj, const char *name) 5093 { 5094 Name_Entry *entry; 5095 5096 STAILQ_FOREACH(entry, &obj->names, link) { 5097 if (strcmp(name, entry->name) == 0) 5098 return (1); 5099 } 5100 return (0); 5101 } 5102 5103 static Obj_Entry * 5104 locate_dependency(const Obj_Entry *obj, const char *name) 5105 { 5106 const Objlist_Entry *entry; 5107 const Needed_Entry *needed; 5108 5109 STAILQ_FOREACH(entry, &list_main, link) { 5110 if (object_match_name(entry->obj, name)) 5111 return entry->obj; 5112 } 5113 5114 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5115 if (strcmp(obj->strtab + needed->name, name) == 0 || 5116 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5117 /* 5118 * If there is DT_NEEDED for the name we are looking for, 5119 * we are all set. Note that object might not be found if 5120 * dependency was not loaded yet, so the function can 5121 * return NULL here. This is expected and handled 5122 * properly by the caller. 5123 */ 5124 return (needed->obj); 5125 } 5126 } 5127 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5128 obj->path, name); 5129 rtld_die(); 5130 } 5131 5132 static int 5133 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5134 const Elf_Vernaux *vna) 5135 { 5136 const Elf_Verdef *vd; 5137 const char *vername; 5138 5139 vername = refobj->strtab + vna->vna_name; 5140 vd = depobj->verdef; 5141 if (vd == NULL) { 5142 _rtld_error("%s: version %s required by %s not defined", 5143 depobj->path, vername, refobj->path); 5144 return (-1); 5145 } 5146 for (;;) { 5147 if (vd->vd_version != VER_DEF_CURRENT) { 5148 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5149 depobj->path, vd->vd_version); 5150 return (-1); 5151 } 5152 if (vna->vna_hash == vd->vd_hash) { 5153 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5154 ((const char *)vd + vd->vd_aux); 5155 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5156 return (0); 5157 } 5158 if (vd->vd_next == 0) 5159 break; 5160 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5161 } 5162 if (vna->vna_flags & VER_FLG_WEAK) 5163 return (0); 5164 _rtld_error("%s: version %s required by %s not found", 5165 depobj->path, vername, refobj->path); 5166 return (-1); 5167 } 5168 5169 static int 5170 rtld_verify_object_versions(Obj_Entry *obj) 5171 { 5172 const Elf_Verneed *vn; 5173 const Elf_Verdef *vd; 5174 const Elf_Verdaux *vda; 5175 const Elf_Vernaux *vna; 5176 const Obj_Entry *depobj; 5177 int maxvernum, vernum; 5178 5179 if (obj->ver_checked) 5180 return (0); 5181 obj->ver_checked = true; 5182 5183 maxvernum = 0; 5184 /* 5185 * Walk over defined and required version records and figure out 5186 * max index used by any of them. Do very basic sanity checking 5187 * while there. 5188 */ 5189 vn = obj->verneed; 5190 while (vn != NULL) { 5191 if (vn->vn_version != VER_NEED_CURRENT) { 5192 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5193 obj->path, vn->vn_version); 5194 return (-1); 5195 } 5196 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5197 for (;;) { 5198 vernum = VER_NEED_IDX(vna->vna_other); 5199 if (vernum > maxvernum) 5200 maxvernum = vernum; 5201 if (vna->vna_next == 0) 5202 break; 5203 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5204 } 5205 if (vn->vn_next == 0) 5206 break; 5207 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5208 } 5209 5210 vd = obj->verdef; 5211 while (vd != NULL) { 5212 if (vd->vd_version != VER_DEF_CURRENT) { 5213 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5214 obj->path, vd->vd_version); 5215 return (-1); 5216 } 5217 vernum = VER_DEF_IDX(vd->vd_ndx); 5218 if (vernum > maxvernum) 5219 maxvernum = vernum; 5220 if (vd->vd_next == 0) 5221 break; 5222 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5223 } 5224 5225 if (maxvernum == 0) 5226 return (0); 5227 5228 /* 5229 * Store version information in array indexable by version index. 5230 * Verify that object version requirements are satisfied along the 5231 * way. 5232 */ 5233 obj->vernum = maxvernum + 1; 5234 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5235 5236 vd = obj->verdef; 5237 while (vd != NULL) { 5238 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5239 vernum = VER_DEF_IDX(vd->vd_ndx); 5240 assert(vernum <= maxvernum); 5241 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5242 obj->vertab[vernum].hash = vd->vd_hash; 5243 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5244 obj->vertab[vernum].file = NULL; 5245 obj->vertab[vernum].flags = 0; 5246 } 5247 if (vd->vd_next == 0) 5248 break; 5249 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5250 } 5251 5252 vn = obj->verneed; 5253 while (vn != NULL) { 5254 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5255 if (depobj == NULL) 5256 return (-1); 5257 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5258 for (;;) { 5259 if (check_object_provided_version(obj, depobj, vna)) 5260 return (-1); 5261 vernum = VER_NEED_IDX(vna->vna_other); 5262 assert(vernum <= maxvernum); 5263 obj->vertab[vernum].hash = vna->vna_hash; 5264 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5265 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5266 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5267 VER_INFO_HIDDEN : 0; 5268 if (vna->vna_next == 0) 5269 break; 5270 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5271 } 5272 if (vn->vn_next == 0) 5273 break; 5274 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5275 } 5276 return 0; 5277 } 5278 5279 static int 5280 rtld_verify_versions(const Objlist *objlist) 5281 { 5282 Objlist_Entry *entry; 5283 int rc; 5284 5285 rc = 0; 5286 STAILQ_FOREACH(entry, objlist, link) { 5287 /* 5288 * Skip dummy objects or objects that have their version requirements 5289 * already checked. 5290 */ 5291 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5292 continue; 5293 if (rtld_verify_object_versions(entry->obj) == -1) { 5294 rc = -1; 5295 if (ld_tracing == NULL) 5296 break; 5297 } 5298 } 5299 if (rc == 0 || ld_tracing != NULL) 5300 rc = rtld_verify_object_versions(&obj_rtld); 5301 return rc; 5302 } 5303 5304 const Ver_Entry * 5305 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5306 { 5307 Elf_Versym vernum; 5308 5309 if (obj->vertab) { 5310 vernum = VER_NDX(obj->versyms[symnum]); 5311 if (vernum >= obj->vernum) { 5312 _rtld_error("%s: symbol %s has wrong verneed value %d", 5313 obj->path, obj->strtab + symnum, vernum); 5314 } else if (obj->vertab[vernum].hash != 0) { 5315 return &obj->vertab[vernum]; 5316 } 5317 } 5318 return NULL; 5319 } 5320 5321 int 5322 _rtld_get_stack_prot(void) 5323 { 5324 5325 return (stack_prot); 5326 } 5327 5328 int 5329 _rtld_is_dlopened(void *arg) 5330 { 5331 Obj_Entry *obj; 5332 RtldLockState lockstate; 5333 int res; 5334 5335 rlock_acquire(rtld_bind_lock, &lockstate); 5336 obj = dlcheck(arg); 5337 if (obj == NULL) 5338 obj = obj_from_addr(arg); 5339 if (obj == NULL) { 5340 _rtld_error("No shared object contains address"); 5341 lock_release(rtld_bind_lock, &lockstate); 5342 return (-1); 5343 } 5344 res = obj->dlopened ? 1 : 0; 5345 lock_release(rtld_bind_lock, &lockstate); 5346 return (res); 5347 } 5348 5349 int 5350 obj_enforce_relro(Obj_Entry *obj) 5351 { 5352 5353 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5354 PROT_READ) == -1) { 5355 _rtld_error("%s: Cannot enforce relro protection: %s", 5356 obj->path, rtld_strerror(errno)); 5357 return (-1); 5358 } 5359 return (0); 5360 } 5361 5362 static void 5363 map_stacks_exec(RtldLockState *lockstate) 5364 { 5365 void (*thr_map_stacks_exec)(void); 5366 5367 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5368 return; 5369 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5370 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5371 if (thr_map_stacks_exec != NULL) { 5372 stack_prot |= PROT_EXEC; 5373 thr_map_stacks_exec(); 5374 } 5375 } 5376 5377 void 5378 symlook_init(SymLook *dst, const char *name) 5379 { 5380 5381 bzero(dst, sizeof(*dst)); 5382 dst->name = name; 5383 dst->hash = elf_hash(name); 5384 dst->hash_gnu = gnu_hash(name); 5385 } 5386 5387 static void 5388 symlook_init_from_req(SymLook *dst, const SymLook *src) 5389 { 5390 5391 dst->name = src->name; 5392 dst->hash = src->hash; 5393 dst->hash_gnu = src->hash_gnu; 5394 dst->ventry = src->ventry; 5395 dst->flags = src->flags; 5396 dst->defobj_out = NULL; 5397 dst->sym_out = NULL; 5398 dst->lockstate = src->lockstate; 5399 } 5400 5401 static int 5402 open_binary_fd(const char *argv0, bool search_in_path) 5403 { 5404 char *pathenv, *pe, binpath[PATH_MAX]; 5405 int fd; 5406 5407 if (search_in_path && strchr(argv0, '/') == NULL) { 5408 pathenv = getenv("PATH"); 5409 if (pathenv == NULL) { 5410 _rtld_error("-p and no PATH environment variable"); 5411 rtld_die(); 5412 } 5413 pathenv = strdup(pathenv); 5414 if (pathenv == NULL) { 5415 _rtld_error("Cannot allocate memory"); 5416 rtld_die(); 5417 } 5418 fd = -1; 5419 errno = ENOENT; 5420 while ((pe = strsep(&pathenv, ":")) != NULL) { 5421 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5422 sizeof(binpath)) 5423 continue; 5424 if (binpath[0] != '\0' && 5425 strlcat(binpath, "/", sizeof(binpath)) >= 5426 sizeof(binpath)) 5427 continue; 5428 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5429 sizeof(binpath)) 5430 continue; 5431 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5432 if (fd != -1 || errno != ENOENT) 5433 break; 5434 } 5435 free(pathenv); 5436 } else { 5437 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5438 } 5439 5440 if (fd == -1) { 5441 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5442 rtld_die(); 5443 } 5444 return (fd); 5445 } 5446 5447 /* 5448 * Parse a set of command-line arguments. 5449 */ 5450 static int 5451 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5452 { 5453 const char *arg; 5454 int fd, i, j, arglen; 5455 char opt; 5456 5457 dbg("Parsing command-line arguments"); 5458 *use_pathp = false; 5459 *fdp = -1; 5460 5461 for (i = 1; i < argc; i++ ) { 5462 arg = argv[i]; 5463 dbg("argv[%d]: '%s'", i, arg); 5464 5465 /* 5466 * rtld arguments end with an explicit "--" or with the first 5467 * non-prefixed argument. 5468 */ 5469 if (strcmp(arg, "--") == 0) { 5470 i++; 5471 break; 5472 } 5473 if (arg[0] != '-') 5474 break; 5475 5476 /* 5477 * All other arguments are single-character options that can 5478 * be combined, so we need to search through `arg` for them. 5479 */ 5480 arglen = strlen(arg); 5481 for (j = 1; j < arglen; j++) { 5482 opt = arg[j]; 5483 if (opt == 'h') { 5484 print_usage(argv[0]); 5485 _exit(0); 5486 } else if (opt == 'f') { 5487 /* 5488 * -f XX can be used to specify a descriptor for the 5489 * binary named at the command line (i.e., the later 5490 * argument will specify the process name but the 5491 * descriptor is what will actually be executed) 5492 */ 5493 if (j != arglen - 1) { 5494 /* -f must be the last option in, e.g., -abcf */ 5495 _rtld_error("Invalid options: %s", arg); 5496 rtld_die(); 5497 } 5498 i++; 5499 fd = parse_integer(argv[i]); 5500 if (fd == -1) { 5501 _rtld_error("Invalid file descriptor: '%s'", 5502 argv[i]); 5503 rtld_die(); 5504 } 5505 *fdp = fd; 5506 break; 5507 } else if (opt == 'p') { 5508 *use_pathp = true; 5509 } else { 5510 _rtld_error("Invalid argument: '%s'", arg); 5511 print_usage(argv[0]); 5512 rtld_die(); 5513 } 5514 } 5515 } 5516 5517 return (i); 5518 } 5519 5520 /* 5521 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5522 */ 5523 static int 5524 parse_integer(const char *str) 5525 { 5526 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5527 const char *orig; 5528 int n; 5529 char c; 5530 5531 orig = str; 5532 n = 0; 5533 for (c = *str; c != '\0'; c = *++str) { 5534 if (c < '0' || c > '9') 5535 return (-1); 5536 5537 n *= RADIX; 5538 n += c - '0'; 5539 } 5540 5541 /* Make sure we actually parsed something. */ 5542 if (str == orig) 5543 return (-1); 5544 return (n); 5545 } 5546 5547 static void 5548 print_usage(const char *argv0) 5549 { 5550 5551 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5552 "\n" 5553 "Options:\n" 5554 " -h Display this help message\n" 5555 " -p Search in PATH for named binary\n" 5556 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5557 " -- End of RTLD options\n" 5558 " <binary> Name of process to execute\n" 5559 " <args> Arguments to the executed process\n", argv0); 5560 } 5561 5562 /* 5563 * Overrides for libc_pic-provided functions. 5564 */ 5565 5566 int 5567 __getosreldate(void) 5568 { 5569 size_t len; 5570 int oid[2]; 5571 int error, osrel; 5572 5573 if (osreldate != 0) 5574 return (osreldate); 5575 5576 oid[0] = CTL_KERN; 5577 oid[1] = KERN_OSRELDATE; 5578 osrel = 0; 5579 len = sizeof(osrel); 5580 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5581 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5582 osreldate = osrel; 5583 return (osreldate); 5584 } 5585 5586 void 5587 exit(int status) 5588 { 5589 5590 _exit(status); 5591 } 5592 5593 void (*__cleanup)(void); 5594 int __isthreaded = 0; 5595 int _thread_autoinit_dummy_decl = 1; 5596 5597 /* 5598 * No unresolved symbols for rtld. 5599 */ 5600 void 5601 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5602 { 5603 } 5604 5605 const char * 5606 rtld_strerror(int errnum) 5607 { 5608 5609 if (errnum < 0 || errnum >= sys_nerr) 5610 return ("Unknown error"); 5611 return (sys_errlist[errnum]); 5612 } 5613