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