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_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(void); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 78 /* Variables that cannot be static: */ 79 extern struct r_debug r_debug; /* For GDB */ 80 extern int _thread_autoinit_dummy_decl; 81 extern char* __progname; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static void digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path); 138 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 139 static int parse_integer(const char *); 140 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 141 static void print_usage(const char *argv0); 142 static void release_object(Obj_Entry *); 143 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 144 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 145 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 146 int flags, RtldLockState *lockstate); 147 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 148 RtldLockState *); 149 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 150 static int rtld_dirname(const char *, char *); 151 static int rtld_dirname_abs(const char *, char *); 152 static void *rtld_dlopen(const char *name, int fd, int mode); 153 static void rtld_exit(void); 154 static char *search_library_path(const char *, const char *, const char *, 155 int *); 156 static char *search_library_pathfds(const char *, const char *, int *); 157 static const void **get_program_var_addr(const char *, RtldLockState *); 158 static void set_program_var(const char *, const void *); 159 static int symlook_default(SymLook *, const Obj_Entry *refobj); 160 static int symlook_global(SymLook *, DoneList *); 161 static void symlook_init_from_req(SymLook *, const SymLook *); 162 static int symlook_list(SymLook *, const Objlist *, DoneList *); 163 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 164 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 165 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 166 static void trace_loaded_objects(Obj_Entry *); 167 static void unlink_object(Obj_Entry *); 168 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 169 static void unref_dag(Obj_Entry *); 170 static void ref_dag(Obj_Entry *); 171 static char *origin_subst_one(Obj_Entry *, char *, const char *, 172 const char *, bool); 173 static char *origin_subst(Obj_Entry *, const char *); 174 static bool obj_resolve_origin(Obj_Entry *obj); 175 static void preinit_main(void); 176 static int rtld_verify_versions(const Objlist *); 177 static int rtld_verify_object_versions(Obj_Entry *); 178 static void object_add_name(Obj_Entry *, const char *); 179 static int object_match_name(const Obj_Entry *, const char *); 180 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 181 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 182 struct dl_phdr_info *phdr_info); 183 static uint32_t gnu_hash(const char *); 184 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 185 const unsigned long); 186 187 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 188 void _r_debug_postinit(struct link_map *) __noinline __exported; 189 190 int __sys_openat(int, const char *, int, ...); 191 192 /* 193 * Data declarations. 194 */ 195 static char *error_message; /* Message for dlerror(), or NULL */ 196 struct r_debug r_debug __exported; /* for GDB; */ 197 static bool libmap_disable; /* Disable libmap */ 198 static bool ld_loadfltr; /* Immediate filters processing */ 199 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 200 static bool trust; /* False for setuid and setgid programs */ 201 static bool dangerous_ld_env; /* True if environment variables have been 202 used to affect the libraries loaded */ 203 bool ld_bind_not; /* Disable PLT update */ 204 static char *ld_bind_now; /* Environment variable for immediate binding */ 205 static char *ld_debug; /* Environment variable for debugging */ 206 static char *ld_library_path; /* Environment variable for search path */ 207 static char *ld_library_dirs; /* Environment variable for library descriptors */ 208 static char *ld_preload; /* Environment variable for libraries to 209 load first */ 210 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 211 static const char *ld_tracing; /* Called from ldd to print libs */ 212 static char *ld_utrace; /* Use utrace() to log events. */ 213 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 214 static Obj_Entry *obj_main; /* The main program shared object */ 215 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 216 static unsigned int obj_count; /* Number of objects in obj_list */ 217 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 218 219 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 220 STAILQ_HEAD_INITIALIZER(list_global); 221 static Objlist list_main = /* Objects loaded at program startup */ 222 STAILQ_HEAD_INITIALIZER(list_main); 223 static Objlist list_fini = /* Objects needing fini() calls */ 224 STAILQ_HEAD_INITIALIZER(list_fini); 225 226 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 227 228 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 229 230 extern Elf_Dyn _DYNAMIC; 231 #pragma weak _DYNAMIC 232 233 int dlclose(void *) __exported; 234 char *dlerror(void) __exported; 235 void *dlopen(const char *, int) __exported; 236 void *fdlopen(int, int) __exported; 237 void *dlsym(void *, const char *) __exported; 238 dlfunc_t dlfunc(void *, const char *) __exported; 239 void *dlvsym(void *, const char *, const char *) __exported; 240 int dladdr(const void *, Dl_info *) __exported; 241 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 242 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 243 int dlinfo(void *, int , void *) __exported; 244 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 245 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 246 int _rtld_get_stack_prot(void) __exported; 247 int _rtld_is_dlopened(void *) __exported; 248 void _rtld_error(const char *, ...) __exported; 249 250 /* Only here to fix -Wmissing-prototypes warnings */ 251 int __getosreldate(void); 252 void __pthread_cxa_finalize(struct dl_phdr_info *a); 253 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 254 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 255 256 257 int npagesizes; 258 static int osreldate; 259 size_t *pagesizes; 260 261 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 262 static int max_stack_flags; 263 264 /* 265 * Global declarations normally provided by crt1. The dynamic linker is 266 * not built with crt1, so we have to provide them ourselves. 267 */ 268 char *__progname; 269 char **environ; 270 271 /* 272 * Used to pass argc, argv to init functions. 273 */ 274 int main_argc; 275 char **main_argv; 276 277 /* 278 * Globals to control TLS allocation. 279 */ 280 size_t tls_last_offset; /* Static TLS offset of last module */ 281 size_t tls_last_size; /* Static TLS size of last module */ 282 size_t tls_static_space; /* Static TLS space allocated */ 283 static size_t tls_static_max_align; 284 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 285 int tls_max_index = 1; /* Largest module index allocated */ 286 287 static bool ld_library_path_rpath = false; 288 289 /* 290 * Globals for path names, and such 291 */ 292 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 293 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 294 const char *ld_path_rtld = _PATH_RTLD; 295 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 296 const char *ld_env_prefix = LD_; 297 298 /* 299 * Fill in a DoneList with an allocation large enough to hold all of 300 * the currently-loaded objects. Keep this as a macro since it calls 301 * alloca and we want that to occur within the scope of the caller. 302 */ 303 #define donelist_init(dlp) \ 304 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 305 assert((dlp)->objs != NULL), \ 306 (dlp)->num_alloc = obj_count, \ 307 (dlp)->num_used = 0) 308 309 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 310 if (ld_utrace != NULL) \ 311 ld_utrace_log(e, h, mb, ms, r, n); \ 312 } while (0) 313 314 static void 315 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 316 int refcnt, const char *name) 317 { 318 struct utrace_rtld ut; 319 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 320 321 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 322 ut.event = event; 323 ut.handle = handle; 324 ut.mapbase = mapbase; 325 ut.mapsize = mapsize; 326 ut.refcnt = refcnt; 327 bzero(ut.name, sizeof(ut.name)); 328 if (name) 329 strlcpy(ut.name, name, sizeof(ut.name)); 330 utrace(&ut, sizeof(ut)); 331 } 332 333 #ifdef RTLD_VARIANT_ENV_NAMES 334 /* 335 * construct the env variable based on the type of binary that's 336 * running. 337 */ 338 static inline const char * 339 _LD(const char *var) 340 { 341 static char buffer[128]; 342 343 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 344 strlcat(buffer, var, sizeof(buffer)); 345 return (buffer); 346 } 347 #else 348 #define _LD(x) LD_ x 349 #endif 350 351 /* 352 * Main entry point for dynamic linking. The first argument is the 353 * stack pointer. The stack is expected to be laid out as described 354 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 355 * Specifically, the stack pointer points to a word containing 356 * ARGC. Following that in the stack is a null-terminated sequence 357 * of pointers to argument strings. Then comes a null-terminated 358 * sequence of pointers to environment strings. Finally, there is a 359 * sequence of "auxiliary vector" entries. 360 * 361 * The second argument points to a place to store the dynamic linker's 362 * exit procedure pointer and the third to a place to store the main 363 * program's object. 364 * 365 * The return value is the main program's entry point. 366 */ 367 func_ptr_type 368 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 369 { 370 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 371 Objlist_Entry *entry; 372 Obj_Entry *last_interposer, *obj, *preload_tail; 373 const Elf_Phdr *phdr; 374 Objlist initlist; 375 RtldLockState lockstate; 376 struct stat st; 377 Elf_Addr *argcp; 378 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 379 const char *argv0; 380 caddr_t imgentry; 381 char buf[MAXPATHLEN]; 382 int argc, fd, i, phnum, rtld_argc; 383 bool dir_enable, explicit_fd, search_in_path; 384 385 /* 386 * On entry, the dynamic linker itself has not been relocated yet. 387 * Be very careful not to reference any global data until after 388 * init_rtld has returned. It is OK to reference file-scope statics 389 * and string constants, and to call static and global functions. 390 */ 391 392 /* Find the auxiliary vector on the stack. */ 393 argcp = sp; 394 argc = *sp++; 395 argv = (char **) sp; 396 sp += argc + 1; /* Skip over arguments and NULL terminator */ 397 env = (char **) sp; 398 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 399 ; 400 aux = (Elf_Auxinfo *) sp; 401 402 /* Digest the auxiliary vector. */ 403 for (i = 0; i < AT_COUNT; i++) 404 aux_info[i] = NULL; 405 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 406 if (auxp->a_type < AT_COUNT) 407 aux_info[auxp->a_type] = auxp; 408 } 409 410 /* Initialize and relocate ourselves. */ 411 assert(aux_info[AT_BASE] != NULL); 412 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 413 414 __progname = obj_rtld.path; 415 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 416 environ = env; 417 main_argc = argc; 418 main_argv = argv; 419 420 trust = !issetugid(); 421 422 md_abi_variant_hook(aux_info); 423 424 fd = -1; 425 if (aux_info[AT_EXECFD] != NULL) { 426 fd = aux_info[AT_EXECFD]->a_un.a_val; 427 } else { 428 assert(aux_info[AT_PHDR] != NULL); 429 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 430 if (phdr == obj_rtld.phdr) { 431 if (!trust) { 432 _rtld_error("Tainted process refusing to run binary %s", 433 argv0); 434 rtld_die(); 435 } 436 dbg("opening main program in direct exec mode"); 437 if (argc >= 2) { 438 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 439 argv0 = argv[rtld_argc]; 440 explicit_fd = (fd != -1); 441 if (!explicit_fd) 442 fd = open_binary_fd(argv0, search_in_path); 443 if (fstat(fd, &st) == -1) { 444 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 445 explicit_fd ? "user-provided descriptor" : argv0, 446 rtld_strerror(errno)); 447 rtld_die(); 448 } 449 450 /* 451 * Rough emulation of the permission checks done by 452 * execve(2), only Unix DACs are checked, ACLs are 453 * ignored. Preserve the semantic of disabling owner 454 * to execute if owner x bit is cleared, even if 455 * others x bit is enabled. 456 * mmap(2) does not allow to mmap with PROT_EXEC if 457 * binary' file comes from noexec mount. We cannot 458 * set VV_TEXT on the binary. 459 */ 460 dir_enable = false; 461 if (st.st_uid == geteuid()) { 462 if ((st.st_mode & S_IXUSR) != 0) 463 dir_enable = true; 464 } else if (st.st_gid == getegid()) { 465 if ((st.st_mode & S_IXGRP) != 0) 466 dir_enable = true; 467 } else if ((st.st_mode & S_IXOTH) != 0) { 468 dir_enable = true; 469 } 470 if (!dir_enable) { 471 _rtld_error("No execute permission for binary %s", 472 argv0); 473 rtld_die(); 474 } 475 476 /* 477 * For direct exec mode, argv[0] is the interpreter 478 * name, we must remove it and shift arguments left 479 * before invoking binary main. Since stack layout 480 * places environment pointers and aux vectors right 481 * after the terminating NULL, we must shift 482 * environment and aux as well. 483 */ 484 main_argc = argc - rtld_argc; 485 for (i = 0; i <= main_argc; i++) 486 argv[i] = argv[i + rtld_argc]; 487 *argcp -= rtld_argc; 488 environ = env = envp = argv + main_argc + 1; 489 do { 490 *envp = *(envp + rtld_argc); 491 envp++; 492 } while (*envp != NULL); 493 aux = auxp = (Elf_Auxinfo *)envp; 494 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 495 for (;; auxp++, auxpf++) { 496 *auxp = *auxpf; 497 if (auxp->a_type == AT_NULL) 498 break; 499 } 500 } else { 501 _rtld_error("No binary"); 502 rtld_die(); 503 } 504 } 505 } 506 507 ld_bind_now = getenv(_LD("BIND_NOW")); 508 509 /* 510 * If the process is tainted, then we un-set the dangerous environment 511 * variables. The process will be marked as tainted until setuid(2) 512 * is called. If any child process calls setuid(2) we do not want any 513 * future processes to honor the potentially un-safe variables. 514 */ 515 if (!trust) { 516 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 517 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 518 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 519 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 520 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 521 _rtld_error("environment corrupt; aborting"); 522 rtld_die(); 523 } 524 } 525 ld_debug = getenv(_LD("DEBUG")); 526 if (ld_bind_now == NULL) 527 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 528 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 529 libmap_override = getenv(_LD("LIBMAP")); 530 ld_library_path = getenv(_LD("LIBRARY_PATH")); 531 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 532 ld_preload = getenv(_LD("PRELOAD")); 533 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 534 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 535 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 536 if (library_path_rpath != NULL) { 537 if (library_path_rpath[0] == 'y' || 538 library_path_rpath[0] == 'Y' || 539 library_path_rpath[0] == '1') 540 ld_library_path_rpath = true; 541 else 542 ld_library_path_rpath = false; 543 } 544 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 545 (ld_library_path != NULL) || (ld_preload != NULL) || 546 (ld_elf_hints_path != NULL) || ld_loadfltr; 547 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 548 ld_utrace = getenv(_LD("UTRACE")); 549 550 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 551 ld_elf_hints_path = ld_elf_hints_default; 552 553 if (ld_debug != NULL && *ld_debug != '\0') 554 debug = 1; 555 dbg("%s is initialized, base address = %p", __progname, 556 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 557 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 558 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 559 560 dbg("initializing thread locks"); 561 lockdflt_init(); 562 563 /* 564 * Load the main program, or process its program header if it is 565 * already loaded. 566 */ 567 if (fd != -1) { /* Load the main program. */ 568 dbg("loading main program"); 569 obj_main = map_object(fd, argv0, NULL); 570 close(fd); 571 if (obj_main == NULL) 572 rtld_die(); 573 max_stack_flags = obj_main->stack_flags; 574 } else { /* Main program already loaded. */ 575 dbg("processing main program's program header"); 576 assert(aux_info[AT_PHDR] != NULL); 577 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 578 assert(aux_info[AT_PHNUM] != NULL); 579 phnum = aux_info[AT_PHNUM]->a_un.a_val; 580 assert(aux_info[AT_PHENT] != NULL); 581 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 582 assert(aux_info[AT_ENTRY] != NULL); 583 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 584 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 585 rtld_die(); 586 } 587 588 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 589 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 590 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 591 if (kexecpath[0] == '/') 592 obj_main->path = kexecpath; 593 else if (getcwd(buf, sizeof(buf)) == NULL || 594 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 595 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 596 obj_main->path = xstrdup(argv0); 597 else 598 obj_main->path = xstrdup(buf); 599 } else { 600 dbg("No AT_EXECPATH or direct exec"); 601 obj_main->path = xstrdup(argv0); 602 } 603 dbg("obj_main path %s", obj_main->path); 604 obj_main->mainprog = true; 605 606 if (aux_info[AT_STACKPROT] != NULL && 607 aux_info[AT_STACKPROT]->a_un.a_val != 0) 608 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 609 610 #ifndef COMPAT_32BIT 611 /* 612 * Get the actual dynamic linker pathname from the executable if 613 * possible. (It should always be possible.) That ensures that 614 * gdb will find the right dynamic linker even if a non-standard 615 * one is being used. 616 */ 617 if (obj_main->interp != NULL && 618 strcmp(obj_main->interp, obj_rtld.path) != 0) { 619 free(obj_rtld.path); 620 obj_rtld.path = xstrdup(obj_main->interp); 621 __progname = obj_rtld.path; 622 } 623 #endif 624 625 digest_dynamic(obj_main, 0); 626 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 627 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 628 obj_main->dynsymcount); 629 630 linkmap_add(obj_main); 631 linkmap_add(&obj_rtld); 632 633 /* Link the main program into the list of objects. */ 634 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 635 obj_count++; 636 obj_loads++; 637 638 /* Initialize a fake symbol for resolving undefined weak references. */ 639 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 640 sym_zero.st_shndx = SHN_UNDEF; 641 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 642 643 if (!libmap_disable) 644 libmap_disable = (bool)lm_init(libmap_override); 645 646 dbg("loading LD_PRELOAD libraries"); 647 if (load_preload_objects() == -1) 648 rtld_die(); 649 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 650 651 dbg("loading needed objects"); 652 if (load_needed_objects(obj_main, 0) == -1) 653 rtld_die(); 654 655 /* Make a list of all objects loaded at startup. */ 656 last_interposer = obj_main; 657 TAILQ_FOREACH(obj, &obj_list, next) { 658 if (obj->marker) 659 continue; 660 if (obj->z_interpose && obj != obj_main) { 661 objlist_put_after(&list_main, last_interposer, obj); 662 last_interposer = obj; 663 } else { 664 objlist_push_tail(&list_main, obj); 665 } 666 obj->refcount++; 667 } 668 669 dbg("checking for required versions"); 670 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 671 rtld_die(); 672 673 if (ld_tracing) { /* We're done */ 674 trace_loaded_objects(obj_main); 675 exit(0); 676 } 677 678 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 679 dump_relocations(obj_main); 680 exit (0); 681 } 682 683 /* 684 * Processing tls relocations requires having the tls offsets 685 * initialized. Prepare offsets before starting initial 686 * relocation processing. 687 */ 688 dbg("initializing initial thread local storage offsets"); 689 STAILQ_FOREACH(entry, &list_main, link) { 690 /* 691 * Allocate all the initial objects out of the static TLS 692 * block even if they didn't ask for it. 693 */ 694 allocate_tls_offset(entry->obj); 695 } 696 697 if (relocate_objects(obj_main, 698 ld_bind_now != NULL && *ld_bind_now != '\0', 699 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 700 rtld_die(); 701 702 dbg("doing copy relocations"); 703 if (do_copy_relocations(obj_main) == -1) 704 rtld_die(); 705 706 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 707 dump_relocations(obj_main); 708 exit (0); 709 } 710 711 ifunc_init(aux); 712 713 /* 714 * Setup TLS for main thread. This must be done after the 715 * relocations are processed, since tls initialization section 716 * might be the subject for relocations. 717 */ 718 dbg("initializing initial thread local storage"); 719 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 720 721 dbg("initializing key program variables"); 722 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 723 set_program_var("environ", env); 724 set_program_var("__elf_aux_vector", aux); 725 726 /* Make a list of init functions to call. */ 727 objlist_init(&initlist); 728 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 729 preload_tail, &initlist); 730 731 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 732 733 map_stacks_exec(NULL); 734 735 if (!obj_main->crt_no_init) { 736 /* 737 * Make sure we don't call the main program's init and fini 738 * functions for binaries linked with old crt1 which calls 739 * _init itself. 740 */ 741 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 742 obj_main->preinit_array = obj_main->init_array = 743 obj_main->fini_array = (Elf_Addr)NULL; 744 } 745 746 /* 747 * Execute MD initializers required before we call the objects' 748 * init functions. 749 */ 750 pre_init(); 751 752 wlock_acquire(rtld_bind_lock, &lockstate); 753 754 dbg("resolving ifuncs"); 755 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 756 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 757 rtld_die(); 758 759 if (obj_main->crt_no_init) 760 preinit_main(); 761 objlist_call_init(&initlist, &lockstate); 762 _r_debug_postinit(&obj_main->linkmap); 763 objlist_clear(&initlist); 764 dbg("loading filtees"); 765 TAILQ_FOREACH(obj, &obj_list, next) { 766 if (obj->marker) 767 continue; 768 if (ld_loadfltr || obj->z_loadfltr) 769 load_filtees(obj, 0, &lockstate); 770 } 771 772 dbg("enforcing main obj relro"); 773 if (obj_enforce_relro(obj_main) == -1) 774 rtld_die(); 775 776 lock_release(rtld_bind_lock, &lockstate); 777 778 dbg("transferring control to program entry point = %p", obj_main->entry); 779 780 /* Return the exit procedure and the program entry point. */ 781 *exit_proc = rtld_exit; 782 *objp = obj_main; 783 return (func_ptr_type) obj_main->entry; 784 } 785 786 void * 787 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 788 { 789 void *ptr; 790 Elf_Addr target; 791 792 ptr = (void *)make_function_pointer(def, obj); 793 target = call_ifunc_resolver(ptr); 794 return ((void *)target); 795 } 796 797 /* 798 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 799 * Changes to this function should be applied there as well. 800 */ 801 Elf_Addr 802 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 803 { 804 const Elf_Rel *rel; 805 const Elf_Sym *def; 806 const Obj_Entry *defobj; 807 Elf_Addr *where; 808 Elf_Addr target; 809 RtldLockState lockstate; 810 811 rlock_acquire(rtld_bind_lock, &lockstate); 812 if (sigsetjmp(lockstate.env, 0) != 0) 813 lock_upgrade(rtld_bind_lock, &lockstate); 814 if (obj->pltrel) 815 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 816 else 817 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 818 819 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 820 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 821 NULL, &lockstate); 822 if (def == NULL) 823 rtld_die(); 824 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 825 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 826 else 827 target = (Elf_Addr)(defobj->relocbase + def->st_value); 828 829 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 830 defobj->strtab + def->st_name, basename(obj->path), 831 (void *)target, basename(defobj->path)); 832 833 /* 834 * Write the new contents for the jmpslot. Note that depending on 835 * architecture, the value which we need to return back to the 836 * lazy binding trampoline may or may not be the target 837 * address. The value returned from reloc_jmpslot() is the value 838 * that the trampoline needs. 839 */ 840 target = reloc_jmpslot(where, target, defobj, obj, rel); 841 lock_release(rtld_bind_lock, &lockstate); 842 return target; 843 } 844 845 /* 846 * Error reporting function. Use it like printf. If formats the message 847 * into a buffer, and sets things up so that the next call to dlerror() 848 * will return the message. 849 */ 850 void 851 _rtld_error(const char *fmt, ...) 852 { 853 static char buf[512]; 854 va_list ap; 855 856 va_start(ap, fmt); 857 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 858 error_message = buf; 859 va_end(ap); 860 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 861 } 862 863 /* 864 * Return a dynamically-allocated copy of the current error message, if any. 865 */ 866 static char * 867 errmsg_save(void) 868 { 869 return error_message == NULL ? NULL : xstrdup(error_message); 870 } 871 872 /* 873 * Restore the current error message from a copy which was previously saved 874 * by errmsg_save(). The copy is freed. 875 */ 876 static void 877 errmsg_restore(char *saved_msg) 878 { 879 if (saved_msg == NULL) 880 error_message = NULL; 881 else { 882 _rtld_error("%s", saved_msg); 883 free(saved_msg); 884 } 885 } 886 887 static const char * 888 basename(const char *name) 889 { 890 const char *p = strrchr(name, '/'); 891 return p != NULL ? p + 1 : name; 892 } 893 894 static struct utsname uts; 895 896 static char * 897 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 898 const char *subst, bool may_free) 899 { 900 char *p, *p1, *res, *resp; 901 int subst_len, kw_len, subst_count, old_len, new_len; 902 903 kw_len = strlen(kw); 904 905 /* 906 * First, count the number of the keyword occurrences, to 907 * preallocate the final string. 908 */ 909 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 910 p1 = strstr(p, kw); 911 if (p1 == NULL) 912 break; 913 } 914 915 /* 916 * If the keyword is not found, just return. 917 * 918 * Return non-substituted string if resolution failed. We 919 * cannot do anything more reasonable, the failure mode of the 920 * caller is unresolved library anyway. 921 */ 922 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 923 return (may_free ? real : xstrdup(real)); 924 if (obj != NULL) 925 subst = obj->origin_path; 926 927 /* 928 * There is indeed something to substitute. Calculate the 929 * length of the resulting string, and allocate it. 930 */ 931 subst_len = strlen(subst); 932 old_len = strlen(real); 933 new_len = old_len + (subst_len - kw_len) * subst_count; 934 res = xmalloc(new_len + 1); 935 936 /* 937 * Now, execute the substitution loop. 938 */ 939 for (p = real, resp = res, *resp = '\0';;) { 940 p1 = strstr(p, kw); 941 if (p1 != NULL) { 942 /* Copy the prefix before keyword. */ 943 memcpy(resp, p, p1 - p); 944 resp += p1 - p; 945 /* Keyword replacement. */ 946 memcpy(resp, subst, subst_len); 947 resp += subst_len; 948 *resp = '\0'; 949 p = p1 + kw_len; 950 } else 951 break; 952 } 953 954 /* Copy to the end of string and finish. */ 955 strcat(resp, p); 956 if (may_free) 957 free(real); 958 return (res); 959 } 960 961 static char * 962 origin_subst(Obj_Entry *obj, const char *real) 963 { 964 char *res1, *res2, *res3, *res4; 965 966 if (obj == NULL || !trust) 967 return (xstrdup(real)); 968 if (uts.sysname[0] == '\0') { 969 if (uname(&uts) != 0) { 970 _rtld_error("utsname failed: %d", errno); 971 return (NULL); 972 } 973 } 974 /* __DECONST is safe here since without may_free real is unchanged */ 975 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 976 false); 977 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 978 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 979 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 980 return (res4); 981 } 982 983 void 984 rtld_die(void) 985 { 986 const char *msg = dlerror(); 987 988 if (msg == NULL) 989 msg = "Fatal error"; 990 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 991 rtld_fdputstr(STDERR_FILENO, msg); 992 rtld_fdputchar(STDERR_FILENO, '\n'); 993 _exit(1); 994 } 995 996 /* 997 * Process a shared object's DYNAMIC section, and save the important 998 * information in its Obj_Entry structure. 999 */ 1000 static void 1001 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1002 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1003 { 1004 const Elf_Dyn *dynp; 1005 Needed_Entry **needed_tail = &obj->needed; 1006 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1007 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1008 const Elf_Hashelt *hashtab; 1009 const Elf32_Word *hashval; 1010 Elf32_Word bkt, nmaskwords; 1011 int bloom_size32; 1012 int plttype = DT_REL; 1013 1014 *dyn_rpath = NULL; 1015 *dyn_soname = NULL; 1016 *dyn_runpath = NULL; 1017 1018 obj->bind_now = false; 1019 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1020 switch (dynp->d_tag) { 1021 1022 case DT_REL: 1023 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1024 break; 1025 1026 case DT_RELSZ: 1027 obj->relsize = dynp->d_un.d_val; 1028 break; 1029 1030 case DT_RELENT: 1031 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1032 break; 1033 1034 case DT_JMPREL: 1035 obj->pltrel = (const Elf_Rel *) 1036 (obj->relocbase + dynp->d_un.d_ptr); 1037 break; 1038 1039 case DT_PLTRELSZ: 1040 obj->pltrelsize = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_RELA: 1044 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1045 break; 1046 1047 case DT_RELASZ: 1048 obj->relasize = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_RELAENT: 1052 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1053 break; 1054 1055 case DT_PLTREL: 1056 plttype = dynp->d_un.d_val; 1057 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1058 break; 1059 1060 case DT_SYMTAB: 1061 obj->symtab = (const Elf_Sym *) 1062 (obj->relocbase + dynp->d_un.d_ptr); 1063 break; 1064 1065 case DT_SYMENT: 1066 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1067 break; 1068 1069 case DT_STRTAB: 1070 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1071 break; 1072 1073 case DT_STRSZ: 1074 obj->strsize = dynp->d_un.d_val; 1075 break; 1076 1077 case DT_VERNEED: 1078 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1079 dynp->d_un.d_val); 1080 break; 1081 1082 case DT_VERNEEDNUM: 1083 obj->verneednum = dynp->d_un.d_val; 1084 break; 1085 1086 case DT_VERDEF: 1087 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1088 dynp->d_un.d_val); 1089 break; 1090 1091 case DT_VERDEFNUM: 1092 obj->verdefnum = dynp->d_un.d_val; 1093 break; 1094 1095 case DT_VERSYM: 1096 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1097 dynp->d_un.d_val); 1098 break; 1099 1100 case DT_HASH: 1101 { 1102 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1103 dynp->d_un.d_ptr); 1104 obj->nbuckets = hashtab[0]; 1105 obj->nchains = hashtab[1]; 1106 obj->buckets = hashtab + 2; 1107 obj->chains = obj->buckets + obj->nbuckets; 1108 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1109 obj->buckets != NULL; 1110 } 1111 break; 1112 1113 case DT_GNU_HASH: 1114 { 1115 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1116 dynp->d_un.d_ptr); 1117 obj->nbuckets_gnu = hashtab[0]; 1118 obj->symndx_gnu = hashtab[1]; 1119 nmaskwords = hashtab[2]; 1120 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1121 obj->maskwords_bm_gnu = nmaskwords - 1; 1122 obj->shift2_gnu = hashtab[3]; 1123 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1124 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1125 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1126 obj->symndx_gnu; 1127 /* Number of bitmask words is required to be power of 2 */ 1128 obj->valid_hash_gnu = powerof2(nmaskwords) && 1129 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1130 } 1131 break; 1132 1133 case DT_NEEDED: 1134 if (!obj->rtld) { 1135 Needed_Entry *nep = NEW(Needed_Entry); 1136 nep->name = dynp->d_un.d_val; 1137 nep->obj = NULL; 1138 nep->next = NULL; 1139 1140 *needed_tail = nep; 1141 needed_tail = &nep->next; 1142 } 1143 break; 1144 1145 case DT_FILTER: 1146 if (!obj->rtld) { 1147 Needed_Entry *nep = NEW(Needed_Entry); 1148 nep->name = dynp->d_un.d_val; 1149 nep->obj = NULL; 1150 nep->next = NULL; 1151 1152 *needed_filtees_tail = nep; 1153 needed_filtees_tail = &nep->next; 1154 } 1155 break; 1156 1157 case DT_AUXILIARY: 1158 if (!obj->rtld) { 1159 Needed_Entry *nep = NEW(Needed_Entry); 1160 nep->name = dynp->d_un.d_val; 1161 nep->obj = NULL; 1162 nep->next = NULL; 1163 1164 *needed_aux_filtees_tail = nep; 1165 needed_aux_filtees_tail = &nep->next; 1166 } 1167 break; 1168 1169 case DT_PLTGOT: 1170 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1171 break; 1172 1173 case DT_TEXTREL: 1174 obj->textrel = true; 1175 break; 1176 1177 case DT_SYMBOLIC: 1178 obj->symbolic = true; 1179 break; 1180 1181 case DT_RPATH: 1182 /* 1183 * We have to wait until later to process this, because we 1184 * might not have gotten the address of the string table yet. 1185 */ 1186 *dyn_rpath = dynp; 1187 break; 1188 1189 case DT_SONAME: 1190 *dyn_soname = dynp; 1191 break; 1192 1193 case DT_RUNPATH: 1194 *dyn_runpath = dynp; 1195 break; 1196 1197 case DT_INIT: 1198 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1199 break; 1200 1201 case DT_PREINIT_ARRAY: 1202 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1203 break; 1204 1205 case DT_PREINIT_ARRAYSZ: 1206 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1207 break; 1208 1209 case DT_INIT_ARRAY: 1210 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1211 break; 1212 1213 case DT_INIT_ARRAYSZ: 1214 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1215 break; 1216 1217 case DT_FINI: 1218 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1219 break; 1220 1221 case DT_FINI_ARRAY: 1222 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1223 break; 1224 1225 case DT_FINI_ARRAYSZ: 1226 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1227 break; 1228 1229 /* 1230 * Don't process DT_DEBUG on MIPS as the dynamic section 1231 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1232 */ 1233 1234 #ifndef __mips__ 1235 case DT_DEBUG: 1236 if (!early) 1237 dbg("Filling in DT_DEBUG entry"); 1238 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1239 break; 1240 #endif 1241 1242 case DT_FLAGS: 1243 if (dynp->d_un.d_val & DF_ORIGIN) 1244 obj->z_origin = true; 1245 if (dynp->d_un.d_val & DF_SYMBOLIC) 1246 obj->symbolic = true; 1247 if (dynp->d_un.d_val & DF_TEXTREL) 1248 obj->textrel = true; 1249 if (dynp->d_un.d_val & DF_BIND_NOW) 1250 obj->bind_now = true; 1251 if (dynp->d_un.d_val & DF_STATIC_TLS) 1252 obj->static_tls = true; 1253 break; 1254 #ifdef __mips__ 1255 case DT_MIPS_LOCAL_GOTNO: 1256 obj->local_gotno = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_MIPS_SYMTABNO: 1260 obj->symtabno = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_GOTSYM: 1264 obj->gotsym = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_MIPS_RLD_MAP: 1268 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1269 break; 1270 1271 case DT_MIPS_RLD_MAP_REL: 1272 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1273 // section relative to the address of the tag itself. 1274 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1275 (Elf_Addr) &r_debug; 1276 break; 1277 1278 case DT_MIPS_PLTGOT: 1279 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1280 dynp->d_un.d_ptr); 1281 break; 1282 1283 #endif 1284 1285 #ifdef __powerpc64__ 1286 case DT_PPC64_GLINK: 1287 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1288 break; 1289 #endif 1290 1291 case DT_FLAGS_1: 1292 if (dynp->d_un.d_val & DF_1_NOOPEN) 1293 obj->z_noopen = true; 1294 if (dynp->d_un.d_val & DF_1_ORIGIN) 1295 obj->z_origin = true; 1296 if (dynp->d_un.d_val & DF_1_GLOBAL) 1297 obj->z_global = true; 1298 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1299 obj->bind_now = true; 1300 if (dynp->d_un.d_val & DF_1_NODELETE) 1301 obj->z_nodelete = true; 1302 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1303 obj->z_loadfltr = true; 1304 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1305 obj->z_interpose = true; 1306 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1307 obj->z_nodeflib = true; 1308 break; 1309 1310 default: 1311 if (!early) { 1312 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1313 (long)dynp->d_tag); 1314 } 1315 break; 1316 } 1317 } 1318 1319 obj->traced = false; 1320 1321 if (plttype == DT_RELA) { 1322 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1323 obj->pltrel = NULL; 1324 obj->pltrelasize = obj->pltrelsize; 1325 obj->pltrelsize = 0; 1326 } 1327 1328 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1329 if (obj->valid_hash_sysv) 1330 obj->dynsymcount = obj->nchains; 1331 else if (obj->valid_hash_gnu) { 1332 obj->dynsymcount = 0; 1333 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1334 if (obj->buckets_gnu[bkt] == 0) 1335 continue; 1336 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1337 do 1338 obj->dynsymcount++; 1339 while ((*hashval++ & 1u) == 0); 1340 } 1341 obj->dynsymcount += obj->symndx_gnu; 1342 } 1343 } 1344 1345 static bool 1346 obj_resolve_origin(Obj_Entry *obj) 1347 { 1348 1349 if (obj->origin_path != NULL) 1350 return (true); 1351 obj->origin_path = xmalloc(PATH_MAX); 1352 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1353 } 1354 1355 static void 1356 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1357 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1358 { 1359 1360 if (obj->z_origin && !obj_resolve_origin(obj)) 1361 rtld_die(); 1362 1363 if (dyn_runpath != NULL) { 1364 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1365 obj->runpath = origin_subst(obj, obj->runpath); 1366 } else if (dyn_rpath != NULL) { 1367 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1368 obj->rpath = origin_subst(obj, obj->rpath); 1369 } 1370 if (dyn_soname != NULL) 1371 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1372 } 1373 1374 static void 1375 digest_dynamic(Obj_Entry *obj, int early) 1376 { 1377 const Elf_Dyn *dyn_rpath; 1378 const Elf_Dyn *dyn_soname; 1379 const Elf_Dyn *dyn_runpath; 1380 1381 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1382 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1383 } 1384 1385 /* 1386 * Process a shared object's program header. This is used only for the 1387 * main program, when the kernel has already loaded the main program 1388 * into memory before calling the dynamic linker. It creates and 1389 * returns an Obj_Entry structure. 1390 */ 1391 static Obj_Entry * 1392 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1393 { 1394 Obj_Entry *obj; 1395 const Elf_Phdr *phlimit = phdr + phnum; 1396 const Elf_Phdr *ph; 1397 Elf_Addr note_start, note_end; 1398 int nsegs = 0; 1399 1400 obj = obj_new(); 1401 for (ph = phdr; ph < phlimit; ph++) { 1402 if (ph->p_type != PT_PHDR) 1403 continue; 1404 1405 obj->phdr = phdr; 1406 obj->phsize = ph->p_memsz; 1407 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1408 break; 1409 } 1410 1411 obj->stack_flags = PF_X | PF_R | PF_W; 1412 1413 for (ph = phdr; ph < phlimit; ph++) { 1414 switch (ph->p_type) { 1415 1416 case PT_INTERP: 1417 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1418 break; 1419 1420 case PT_LOAD: 1421 if (nsegs == 0) { /* First load segment */ 1422 obj->vaddrbase = trunc_page(ph->p_vaddr); 1423 obj->mapbase = obj->vaddrbase + obj->relocbase; 1424 } else { /* Last load segment */ 1425 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1426 obj->vaddrbase; 1427 } 1428 nsegs++; 1429 break; 1430 1431 case PT_DYNAMIC: 1432 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1433 break; 1434 1435 case PT_TLS: 1436 obj->tlsindex = 1; 1437 obj->tlssize = ph->p_memsz; 1438 obj->tlsalign = ph->p_align; 1439 obj->tlsinitsize = ph->p_filesz; 1440 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1441 break; 1442 1443 case PT_GNU_STACK: 1444 obj->stack_flags = ph->p_flags; 1445 break; 1446 1447 case PT_GNU_RELRO: 1448 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1449 obj->relro_size = round_page(ph->p_memsz); 1450 break; 1451 1452 case PT_NOTE: 1453 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1454 note_end = note_start + ph->p_filesz; 1455 digest_notes(obj, note_start, note_end); 1456 break; 1457 } 1458 } 1459 if (nsegs < 1) { 1460 _rtld_error("%s: too few PT_LOAD segments", path); 1461 return NULL; 1462 } 1463 1464 obj->entry = entry; 1465 return obj; 1466 } 1467 1468 void 1469 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1470 { 1471 const Elf_Note *note; 1472 const char *note_name; 1473 uintptr_t p; 1474 1475 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1476 note = (const Elf_Note *)((const char *)(note + 1) + 1477 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1478 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1479 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1480 note->n_descsz != sizeof(int32_t)) 1481 continue; 1482 if (note->n_type != NT_FREEBSD_ABI_TAG && 1483 note->n_type != NT_FREEBSD_FEATURE_CTL && 1484 note->n_type != NT_FREEBSD_NOINIT_TAG) 1485 continue; 1486 note_name = (const char *)(note + 1); 1487 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1488 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1489 continue; 1490 switch (note->n_type) { 1491 case NT_FREEBSD_ABI_TAG: 1492 /* FreeBSD osrel note */ 1493 p = (uintptr_t)(note + 1); 1494 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1495 obj->osrel = *(const int32_t *)(p); 1496 dbg("note osrel %d", obj->osrel); 1497 break; 1498 case NT_FREEBSD_FEATURE_CTL: 1499 /* FreeBSD ABI feature control note */ 1500 p = (uintptr_t)(note + 1); 1501 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1502 obj->fctl0 = *(const uint32_t *)(p); 1503 dbg("note fctl0 %#x", obj->fctl0); 1504 break; 1505 case NT_FREEBSD_NOINIT_TAG: 1506 /* FreeBSD 'crt does not call init' note */ 1507 obj->crt_no_init = true; 1508 dbg("note crt_no_init"); 1509 break; 1510 } 1511 } 1512 } 1513 1514 static Obj_Entry * 1515 dlcheck(void *handle) 1516 { 1517 Obj_Entry *obj; 1518 1519 TAILQ_FOREACH(obj, &obj_list, next) { 1520 if (obj == (Obj_Entry *) handle) 1521 break; 1522 } 1523 1524 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1525 _rtld_error("Invalid shared object handle %p", handle); 1526 return NULL; 1527 } 1528 return obj; 1529 } 1530 1531 /* 1532 * If the given object is already in the donelist, return true. Otherwise 1533 * add the object to the list and return false. 1534 */ 1535 static bool 1536 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1537 { 1538 unsigned int i; 1539 1540 for (i = 0; i < dlp->num_used; i++) 1541 if (dlp->objs[i] == obj) 1542 return true; 1543 /* 1544 * Our donelist allocation should always be sufficient. But if 1545 * our threads locking isn't working properly, more shared objects 1546 * could have been loaded since we allocated the list. That should 1547 * never happen, but we'll handle it properly just in case it does. 1548 */ 1549 if (dlp->num_used < dlp->num_alloc) 1550 dlp->objs[dlp->num_used++] = obj; 1551 return false; 1552 } 1553 1554 /* 1555 * Hash function for symbol table lookup. Don't even think about changing 1556 * this. It is specified by the System V ABI. 1557 */ 1558 unsigned long 1559 elf_hash(const char *name) 1560 { 1561 const unsigned char *p = (const unsigned char *) name; 1562 unsigned long h = 0; 1563 unsigned long g; 1564 1565 while (*p != '\0') { 1566 h = (h << 4) + *p++; 1567 if ((g = h & 0xf0000000) != 0) 1568 h ^= g >> 24; 1569 h &= ~g; 1570 } 1571 return h; 1572 } 1573 1574 /* 1575 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1576 * unsigned in case it's implemented with a wider type. 1577 */ 1578 static uint32_t 1579 gnu_hash(const char *s) 1580 { 1581 uint32_t h; 1582 unsigned char c; 1583 1584 h = 5381; 1585 for (c = *s; c != '\0'; c = *++s) 1586 h = h * 33 + c; 1587 return (h & 0xffffffff); 1588 } 1589 1590 1591 /* 1592 * Find the library with the given name, and return its full pathname. 1593 * The returned string is dynamically allocated. Generates an error 1594 * message and returns NULL if the library cannot be found. 1595 * 1596 * If the second argument is non-NULL, then it refers to an already- 1597 * loaded shared object, whose library search path will be searched. 1598 * 1599 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1600 * descriptor (which is close-on-exec) will be passed out via the third 1601 * argument. 1602 * 1603 * The search order is: 1604 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1605 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1606 * LD_LIBRARY_PATH 1607 * DT_RUNPATH in the referencing file 1608 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1609 * from list) 1610 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1611 * 1612 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1613 */ 1614 static char * 1615 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1616 { 1617 char *pathname, *refobj_path; 1618 const char *name; 1619 bool nodeflib, objgiven; 1620 1621 objgiven = refobj != NULL; 1622 1623 if (libmap_disable || !objgiven || 1624 (name = lm_find(refobj->path, xname)) == NULL) 1625 name = xname; 1626 1627 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1628 if (name[0] != '/' && !trust) { 1629 _rtld_error("Absolute pathname required " 1630 "for shared object \"%s\"", name); 1631 return (NULL); 1632 } 1633 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1634 __DECONST(char *, name))); 1635 } 1636 1637 dbg(" Searching for \"%s\"", name); 1638 refobj_path = objgiven ? refobj->path : NULL; 1639 1640 /* 1641 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1642 * back to pre-conforming behaviour if user requested so with 1643 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1644 * nodeflib. 1645 */ 1646 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1647 pathname = search_library_path(name, ld_library_path, 1648 refobj_path, fdp); 1649 if (pathname != NULL) 1650 return (pathname); 1651 if (refobj != NULL) { 1652 pathname = search_library_path(name, refobj->rpath, 1653 refobj_path, fdp); 1654 if (pathname != NULL) 1655 return (pathname); 1656 } 1657 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1658 if (pathname != NULL) 1659 return (pathname); 1660 pathname = search_library_path(name, gethints(false), 1661 refobj_path, fdp); 1662 if (pathname != NULL) 1663 return (pathname); 1664 pathname = search_library_path(name, ld_standard_library_path, 1665 refobj_path, fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 } else { 1669 nodeflib = objgiven ? refobj->z_nodeflib : false; 1670 if (objgiven) { 1671 pathname = search_library_path(name, refobj->rpath, 1672 refobj->path, fdp); 1673 if (pathname != NULL) 1674 return (pathname); 1675 } 1676 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1677 pathname = search_library_path(name, obj_main->rpath, 1678 refobj_path, fdp); 1679 if (pathname != NULL) 1680 return (pathname); 1681 } 1682 pathname = search_library_path(name, ld_library_path, 1683 refobj_path, fdp); 1684 if (pathname != NULL) 1685 return (pathname); 1686 if (objgiven) { 1687 pathname = search_library_path(name, refobj->runpath, 1688 refobj_path, fdp); 1689 if (pathname != NULL) 1690 return (pathname); 1691 } 1692 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1693 if (pathname != NULL) 1694 return (pathname); 1695 pathname = search_library_path(name, gethints(nodeflib), 1696 refobj_path, fdp); 1697 if (pathname != NULL) 1698 return (pathname); 1699 if (objgiven && !nodeflib) { 1700 pathname = search_library_path(name, 1701 ld_standard_library_path, refobj_path, fdp); 1702 if (pathname != NULL) 1703 return (pathname); 1704 } 1705 } 1706 1707 if (objgiven && refobj->path != NULL) { 1708 _rtld_error("Shared object \"%s\" not found, " 1709 "required by \"%s\"", name, basename(refobj->path)); 1710 } else { 1711 _rtld_error("Shared object \"%s\" not found", name); 1712 } 1713 return (NULL); 1714 } 1715 1716 /* 1717 * Given a symbol number in a referencing object, find the corresponding 1718 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1719 * no definition was found. Returns a pointer to the Obj_Entry of the 1720 * defining object via the reference parameter DEFOBJ_OUT. 1721 */ 1722 const Elf_Sym * 1723 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1724 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1725 RtldLockState *lockstate) 1726 { 1727 const Elf_Sym *ref; 1728 const Elf_Sym *def; 1729 const Obj_Entry *defobj; 1730 const Ver_Entry *ve; 1731 SymLook req; 1732 const char *name; 1733 int res; 1734 1735 /* 1736 * If we have already found this symbol, get the information from 1737 * the cache. 1738 */ 1739 if (symnum >= refobj->dynsymcount) 1740 return NULL; /* Bad object */ 1741 if (cache != NULL && cache[symnum].sym != NULL) { 1742 *defobj_out = cache[symnum].obj; 1743 return cache[symnum].sym; 1744 } 1745 1746 ref = refobj->symtab + symnum; 1747 name = refobj->strtab + ref->st_name; 1748 def = NULL; 1749 defobj = NULL; 1750 ve = NULL; 1751 1752 /* 1753 * We don't have to do a full scale lookup if the symbol is local. 1754 * We know it will bind to the instance in this load module; to 1755 * which we already have a pointer (ie ref). By not doing a lookup, 1756 * we not only improve performance, but it also avoids unresolvable 1757 * symbols when local symbols are not in the hash table. This has 1758 * been seen with the ia64 toolchain. 1759 */ 1760 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1761 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1762 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1763 symnum); 1764 } 1765 symlook_init(&req, name); 1766 req.flags = flags; 1767 ve = req.ventry = fetch_ventry(refobj, symnum); 1768 req.lockstate = lockstate; 1769 res = symlook_default(&req, refobj); 1770 if (res == 0) { 1771 def = req.sym_out; 1772 defobj = req.defobj_out; 1773 } 1774 } else { 1775 def = ref; 1776 defobj = refobj; 1777 } 1778 1779 /* 1780 * If we found no definition and the reference is weak, treat the 1781 * symbol as having the value zero. 1782 */ 1783 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1784 def = &sym_zero; 1785 defobj = obj_main; 1786 } 1787 1788 if (def != NULL) { 1789 *defobj_out = defobj; 1790 /* Record the information in the cache to avoid subsequent lookups. */ 1791 if (cache != NULL) { 1792 cache[symnum].sym = def; 1793 cache[symnum].obj = defobj; 1794 } 1795 } else { 1796 if (refobj != &obj_rtld) 1797 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1798 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1799 } 1800 return def; 1801 } 1802 1803 /* 1804 * Return the search path from the ldconfig hints file, reading it if 1805 * necessary. If nostdlib is true, then the default search paths are 1806 * not added to result. 1807 * 1808 * Returns NULL if there are problems with the hints file, 1809 * or if the search path there is empty. 1810 */ 1811 static const char * 1812 gethints(bool nostdlib) 1813 { 1814 static char *filtered_path; 1815 static const char *hints; 1816 static struct elfhints_hdr hdr; 1817 struct fill_search_info_args sargs, hargs; 1818 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1819 struct dl_serpath *SLPpath, *hintpath; 1820 char *p; 1821 struct stat hint_stat; 1822 unsigned int SLPndx, hintndx, fndx, fcount; 1823 int fd; 1824 size_t flen; 1825 uint32_t dl; 1826 bool skip; 1827 1828 /* First call, read the hints file */ 1829 if (hints == NULL) { 1830 /* Keep from trying again in case the hints file is bad. */ 1831 hints = ""; 1832 1833 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1834 return (NULL); 1835 1836 /* 1837 * Check of hdr.dirlistlen value against type limit 1838 * intends to pacify static analyzers. Further 1839 * paranoia leads to checks that dirlist is fully 1840 * contained in the file range. 1841 */ 1842 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1843 hdr.magic != ELFHINTS_MAGIC || 1844 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1845 fstat(fd, &hint_stat) == -1) { 1846 cleanup1: 1847 close(fd); 1848 hdr.dirlistlen = 0; 1849 return (NULL); 1850 } 1851 dl = hdr.strtab; 1852 if (dl + hdr.dirlist < dl) 1853 goto cleanup1; 1854 dl += hdr.dirlist; 1855 if (dl + hdr.dirlistlen < dl) 1856 goto cleanup1; 1857 dl += hdr.dirlistlen; 1858 if (dl > hint_stat.st_size) 1859 goto cleanup1; 1860 p = xmalloc(hdr.dirlistlen + 1); 1861 if (pread(fd, p, hdr.dirlistlen + 1, 1862 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1863 p[hdr.dirlistlen] != '\0') { 1864 free(p); 1865 goto cleanup1; 1866 } 1867 hints = p; 1868 close(fd); 1869 } 1870 1871 /* 1872 * If caller agreed to receive list which includes the default 1873 * paths, we are done. Otherwise, if we still did not 1874 * calculated filtered result, do it now. 1875 */ 1876 if (!nostdlib) 1877 return (hints[0] != '\0' ? hints : NULL); 1878 if (filtered_path != NULL) 1879 goto filt_ret; 1880 1881 /* 1882 * Obtain the list of all configured search paths, and the 1883 * list of the default paths. 1884 * 1885 * First estimate the size of the results. 1886 */ 1887 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1888 smeta.dls_cnt = 0; 1889 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1890 hmeta.dls_cnt = 0; 1891 1892 sargs.request = RTLD_DI_SERINFOSIZE; 1893 sargs.serinfo = &smeta; 1894 hargs.request = RTLD_DI_SERINFOSIZE; 1895 hargs.serinfo = &hmeta; 1896 1897 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1898 &sargs); 1899 path_enumerate(hints, fill_search_info, NULL, &hargs); 1900 1901 SLPinfo = xmalloc(smeta.dls_size); 1902 hintinfo = xmalloc(hmeta.dls_size); 1903 1904 /* 1905 * Next fetch both sets of paths. 1906 */ 1907 sargs.request = RTLD_DI_SERINFO; 1908 sargs.serinfo = SLPinfo; 1909 sargs.serpath = &SLPinfo->dls_serpath[0]; 1910 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1911 1912 hargs.request = RTLD_DI_SERINFO; 1913 hargs.serinfo = hintinfo; 1914 hargs.serpath = &hintinfo->dls_serpath[0]; 1915 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1916 1917 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1918 &sargs); 1919 path_enumerate(hints, fill_search_info, NULL, &hargs); 1920 1921 /* 1922 * Now calculate the difference between two sets, by excluding 1923 * standard paths from the full set. 1924 */ 1925 fndx = 0; 1926 fcount = 0; 1927 filtered_path = xmalloc(hdr.dirlistlen + 1); 1928 hintpath = &hintinfo->dls_serpath[0]; 1929 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1930 skip = false; 1931 SLPpath = &SLPinfo->dls_serpath[0]; 1932 /* 1933 * Check each standard path against current. 1934 */ 1935 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1936 /* matched, skip the path */ 1937 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1938 skip = true; 1939 break; 1940 } 1941 } 1942 if (skip) 1943 continue; 1944 /* 1945 * Not matched against any standard path, add the path 1946 * to result. Separate consequtive paths with ':'. 1947 */ 1948 if (fcount > 0) { 1949 filtered_path[fndx] = ':'; 1950 fndx++; 1951 } 1952 fcount++; 1953 flen = strlen(hintpath->dls_name); 1954 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1955 fndx += flen; 1956 } 1957 filtered_path[fndx] = '\0'; 1958 1959 free(SLPinfo); 1960 free(hintinfo); 1961 1962 filt_ret: 1963 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1964 } 1965 1966 static void 1967 init_dag(Obj_Entry *root) 1968 { 1969 const Needed_Entry *needed; 1970 const Objlist_Entry *elm; 1971 DoneList donelist; 1972 1973 if (root->dag_inited) 1974 return; 1975 donelist_init(&donelist); 1976 1977 /* Root object belongs to own DAG. */ 1978 objlist_push_tail(&root->dldags, root); 1979 objlist_push_tail(&root->dagmembers, root); 1980 donelist_check(&donelist, root); 1981 1982 /* 1983 * Add dependencies of root object to DAG in breadth order 1984 * by exploiting the fact that each new object get added 1985 * to the tail of the dagmembers list. 1986 */ 1987 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1988 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1989 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1990 continue; 1991 objlist_push_tail(&needed->obj->dldags, root); 1992 objlist_push_tail(&root->dagmembers, needed->obj); 1993 } 1994 } 1995 root->dag_inited = true; 1996 } 1997 1998 static void 1999 init_marker(Obj_Entry *marker) 2000 { 2001 2002 bzero(marker, sizeof(*marker)); 2003 marker->marker = true; 2004 } 2005 2006 Obj_Entry * 2007 globallist_curr(const Obj_Entry *obj) 2008 { 2009 2010 for (;;) { 2011 if (obj == NULL) 2012 return (NULL); 2013 if (!obj->marker) 2014 return (__DECONST(Obj_Entry *, obj)); 2015 obj = TAILQ_PREV(obj, obj_entry_q, next); 2016 } 2017 } 2018 2019 Obj_Entry * 2020 globallist_next(const Obj_Entry *obj) 2021 { 2022 2023 for (;;) { 2024 obj = TAILQ_NEXT(obj, next); 2025 if (obj == NULL) 2026 return (NULL); 2027 if (!obj->marker) 2028 return (__DECONST(Obj_Entry *, obj)); 2029 } 2030 } 2031 2032 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2033 static void 2034 hold_object(Obj_Entry *obj) 2035 { 2036 2037 obj->holdcount++; 2038 } 2039 2040 static void 2041 unhold_object(Obj_Entry *obj) 2042 { 2043 2044 assert(obj->holdcount > 0); 2045 if (--obj->holdcount == 0 && obj->unholdfree) 2046 release_object(obj); 2047 } 2048 2049 static void 2050 process_z(Obj_Entry *root) 2051 { 2052 const Objlist_Entry *elm; 2053 Obj_Entry *obj; 2054 2055 /* 2056 * Walk over object DAG and process every dependent object 2057 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2058 * to grow their own DAG. 2059 * 2060 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2061 * symlook_global() to work. 2062 * 2063 * For DF_1_NODELETE, the DAG should have its reference upped. 2064 */ 2065 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2066 obj = elm->obj; 2067 if (obj == NULL) 2068 continue; 2069 if (obj->z_nodelete && !obj->ref_nodel) { 2070 dbg("obj %s -z nodelete", obj->path); 2071 init_dag(obj); 2072 ref_dag(obj); 2073 obj->ref_nodel = true; 2074 } 2075 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2076 dbg("obj %s -z global", obj->path); 2077 objlist_push_tail(&list_global, obj); 2078 init_dag(obj); 2079 } 2080 } 2081 } 2082 /* 2083 * Initialize the dynamic linker. The argument is the address at which 2084 * the dynamic linker has been mapped into memory. The primary task of 2085 * this function is to relocate the dynamic linker. 2086 */ 2087 static void 2088 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2089 { 2090 Obj_Entry objtmp; /* Temporary rtld object */ 2091 const Elf_Ehdr *ehdr; 2092 const Elf_Dyn *dyn_rpath; 2093 const Elf_Dyn *dyn_soname; 2094 const Elf_Dyn *dyn_runpath; 2095 2096 #ifdef RTLD_INIT_PAGESIZES_EARLY 2097 /* The page size is required by the dynamic memory allocator. */ 2098 init_pagesizes(aux_info); 2099 #endif 2100 2101 /* 2102 * Conjure up an Obj_Entry structure for the dynamic linker. 2103 * 2104 * The "path" member can't be initialized yet because string constants 2105 * cannot yet be accessed. Below we will set it correctly. 2106 */ 2107 memset(&objtmp, 0, sizeof(objtmp)); 2108 objtmp.path = NULL; 2109 objtmp.rtld = true; 2110 objtmp.mapbase = mapbase; 2111 #ifdef PIC 2112 objtmp.relocbase = mapbase; 2113 #endif 2114 2115 objtmp.dynamic = rtld_dynamic(&objtmp); 2116 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2117 assert(objtmp.needed == NULL); 2118 #if !defined(__mips__) 2119 /* MIPS has a bogus DT_TEXTREL. */ 2120 assert(!objtmp.textrel); 2121 #endif 2122 /* 2123 * Temporarily put the dynamic linker entry into the object list, so 2124 * that symbols can be found. 2125 */ 2126 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2127 2128 ehdr = (Elf_Ehdr *)mapbase; 2129 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2130 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2131 2132 /* Initialize the object list. */ 2133 TAILQ_INIT(&obj_list); 2134 2135 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2136 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2137 2138 #ifndef RTLD_INIT_PAGESIZES_EARLY 2139 /* The page size is required by the dynamic memory allocator. */ 2140 init_pagesizes(aux_info); 2141 #endif 2142 2143 if (aux_info[AT_OSRELDATE] != NULL) 2144 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2145 2146 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2147 2148 /* Replace the path with a dynamically allocated copy. */ 2149 obj_rtld.path = xstrdup(ld_path_rtld); 2150 2151 r_debug.r_brk = r_debug_state; 2152 r_debug.r_state = RT_CONSISTENT; 2153 } 2154 2155 /* 2156 * Retrieve the array of supported page sizes. The kernel provides the page 2157 * sizes in increasing order. 2158 */ 2159 static void 2160 init_pagesizes(Elf_Auxinfo **aux_info) 2161 { 2162 static size_t psa[MAXPAGESIZES]; 2163 int mib[2]; 2164 size_t len, size; 2165 2166 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2167 NULL) { 2168 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2169 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2170 } else { 2171 len = 2; 2172 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2173 size = sizeof(psa); 2174 else { 2175 /* As a fallback, retrieve the base page size. */ 2176 size = sizeof(psa[0]); 2177 if (aux_info[AT_PAGESZ] != NULL) { 2178 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2179 goto psa_filled; 2180 } else { 2181 mib[0] = CTL_HW; 2182 mib[1] = HW_PAGESIZE; 2183 len = 2; 2184 } 2185 } 2186 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2187 _rtld_error("sysctl for hw.pagesize(s) failed"); 2188 rtld_die(); 2189 } 2190 psa_filled: 2191 pagesizes = psa; 2192 } 2193 npagesizes = size / sizeof(pagesizes[0]); 2194 /* Discard any invalid entries at the end of the array. */ 2195 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2196 npagesizes--; 2197 } 2198 2199 /* 2200 * Add the init functions from a needed object list (and its recursive 2201 * needed objects) to "list". This is not used directly; it is a helper 2202 * function for initlist_add_objects(). The write lock must be held 2203 * when this function is called. 2204 */ 2205 static void 2206 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2207 { 2208 /* Recursively process the successor needed objects. */ 2209 if (needed->next != NULL) 2210 initlist_add_neededs(needed->next, list); 2211 2212 /* Process the current needed object. */ 2213 if (needed->obj != NULL) 2214 initlist_add_objects(needed->obj, needed->obj, list); 2215 } 2216 2217 /* 2218 * Scan all of the DAGs rooted in the range of objects from "obj" to 2219 * "tail" and add their init functions to "list". This recurses over 2220 * the DAGs and ensure the proper init ordering such that each object's 2221 * needed libraries are initialized before the object itself. At the 2222 * same time, this function adds the objects to the global finalization 2223 * list "list_fini" in the opposite order. The write lock must be 2224 * held when this function is called. 2225 */ 2226 static void 2227 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2228 { 2229 Obj_Entry *nobj; 2230 2231 if (obj->init_scanned || obj->init_done) 2232 return; 2233 obj->init_scanned = true; 2234 2235 /* Recursively process the successor objects. */ 2236 nobj = globallist_next(obj); 2237 if (nobj != NULL && obj != tail) 2238 initlist_add_objects(nobj, tail, list); 2239 2240 /* Recursively process the needed objects. */ 2241 if (obj->needed != NULL) 2242 initlist_add_neededs(obj->needed, list); 2243 if (obj->needed_filtees != NULL) 2244 initlist_add_neededs(obj->needed_filtees, list); 2245 if (obj->needed_aux_filtees != NULL) 2246 initlist_add_neededs(obj->needed_aux_filtees, list); 2247 2248 /* Add the object to the init list. */ 2249 objlist_push_tail(list, obj); 2250 2251 /* Add the object to the global fini list in the reverse order. */ 2252 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2253 && !obj->on_fini_list) { 2254 objlist_push_head(&list_fini, obj); 2255 obj->on_fini_list = true; 2256 } 2257 } 2258 2259 #ifndef FPTR_TARGET 2260 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2261 #endif 2262 2263 static void 2264 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2265 { 2266 Needed_Entry *needed, *needed1; 2267 2268 for (needed = n; needed != NULL; needed = needed->next) { 2269 if (needed->obj != NULL) { 2270 dlclose_locked(needed->obj, lockstate); 2271 needed->obj = NULL; 2272 } 2273 } 2274 for (needed = n; needed != NULL; needed = needed1) { 2275 needed1 = needed->next; 2276 free(needed); 2277 } 2278 } 2279 2280 static void 2281 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2282 { 2283 2284 free_needed_filtees(obj->needed_filtees, lockstate); 2285 obj->needed_filtees = NULL; 2286 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2287 obj->needed_aux_filtees = NULL; 2288 obj->filtees_loaded = false; 2289 } 2290 2291 static void 2292 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2293 RtldLockState *lockstate) 2294 { 2295 2296 for (; needed != NULL; needed = needed->next) { 2297 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2298 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2299 RTLD_LOCAL, lockstate); 2300 } 2301 } 2302 2303 static void 2304 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2305 { 2306 2307 lock_restart_for_upgrade(lockstate); 2308 if (!obj->filtees_loaded) { 2309 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2310 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2311 obj->filtees_loaded = true; 2312 } 2313 } 2314 2315 static int 2316 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2317 { 2318 Obj_Entry *obj1; 2319 2320 for (; needed != NULL; needed = needed->next) { 2321 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2322 flags & ~RTLD_LO_NOLOAD); 2323 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2324 return (-1); 2325 } 2326 return (0); 2327 } 2328 2329 /* 2330 * Given a shared object, traverse its list of needed objects, and load 2331 * each of them. Returns 0 on success. Generates an error message and 2332 * returns -1 on failure. 2333 */ 2334 static int 2335 load_needed_objects(Obj_Entry *first, int flags) 2336 { 2337 Obj_Entry *obj; 2338 2339 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2340 if (obj->marker) 2341 continue; 2342 if (process_needed(obj, obj->needed, flags) == -1) 2343 return (-1); 2344 } 2345 return (0); 2346 } 2347 2348 static int 2349 load_preload_objects(void) 2350 { 2351 char *p = ld_preload; 2352 Obj_Entry *obj; 2353 static const char delim[] = " \t:;"; 2354 2355 if (p == NULL) 2356 return 0; 2357 2358 p += strspn(p, delim); 2359 while (*p != '\0') { 2360 size_t len = strcspn(p, delim); 2361 char savech; 2362 2363 savech = p[len]; 2364 p[len] = '\0'; 2365 obj = load_object(p, -1, NULL, 0); 2366 if (obj == NULL) 2367 return -1; /* XXX - cleanup */ 2368 obj->z_interpose = true; 2369 p[len] = savech; 2370 p += len; 2371 p += strspn(p, delim); 2372 } 2373 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2374 return 0; 2375 } 2376 2377 static const char * 2378 printable_path(const char *path) 2379 { 2380 2381 return (path == NULL ? "<unknown>" : path); 2382 } 2383 2384 /* 2385 * Load a shared object into memory, if it is not already loaded. The 2386 * object may be specified by name or by user-supplied file descriptor 2387 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2388 * duplicate is. 2389 * 2390 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2391 * on failure. 2392 */ 2393 static Obj_Entry * 2394 load_object(const char *name, int fd_u, const Obj_Entry *refobj, 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 = open(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 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2903 return (-1); 2904 2905 /* 2906 * Set up the magic number and version in the Obj_Entry. These 2907 * were checked in the crt1.o from the original ElfKit, so we 2908 * set them for backward compatibility. 2909 */ 2910 obj->magic = RTLD_MAGIC; 2911 obj->version = RTLD_VERSION; 2912 2913 return (0); 2914 } 2915 2916 /* 2917 * Relocate newly-loaded shared objects. The argument is a pointer to 2918 * the Obj_Entry for the first such object. All objects from the first 2919 * to the end of the list of objects are relocated. Returns 0 on success, 2920 * or -1 on failure. 2921 */ 2922 static int 2923 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2924 int flags, RtldLockState *lockstate) 2925 { 2926 Obj_Entry *obj; 2927 int error; 2928 2929 for (error = 0, obj = first; obj != NULL; 2930 obj = TAILQ_NEXT(obj, next)) { 2931 if (obj->marker) 2932 continue; 2933 error = relocate_object(obj, bind_now, rtldobj, flags, 2934 lockstate); 2935 if (error == -1) 2936 break; 2937 } 2938 return (error); 2939 } 2940 2941 /* 2942 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2943 * referencing STT_GNU_IFUNC symbols is postponed till the other 2944 * relocations are done. The indirect functions specified as 2945 * ifunc are allowed to call other symbols, so we need to have 2946 * objects relocated before asking for resolution from indirects. 2947 * 2948 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2949 * instead of the usual lazy handling of PLT slots. It is 2950 * consistent with how GNU does it. 2951 */ 2952 static int 2953 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2954 RtldLockState *lockstate) 2955 { 2956 2957 if (obj->ifuncs_resolved) 2958 return (0); 2959 obj->ifuncs_resolved = true; 2960 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 2961 return (0); 2962 if (obj_disable_relro(obj) == -1 || 2963 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 2964 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2965 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 2966 obj_enforce_relro(obj) == -1) 2967 return (-1); 2968 return (0); 2969 } 2970 2971 static int 2972 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2973 RtldLockState *lockstate) 2974 { 2975 Objlist_Entry *elm; 2976 Obj_Entry *obj; 2977 2978 STAILQ_FOREACH(elm, list, link) { 2979 obj = elm->obj; 2980 if (obj->marker) 2981 continue; 2982 if (resolve_object_ifunc(obj, bind_now, flags, 2983 lockstate) == -1) 2984 return (-1); 2985 } 2986 return (0); 2987 } 2988 2989 /* 2990 * Cleanup procedure. It will be called (by the atexit mechanism) just 2991 * before the process exits. 2992 */ 2993 static void 2994 rtld_exit(void) 2995 { 2996 RtldLockState lockstate; 2997 2998 wlock_acquire(rtld_bind_lock, &lockstate); 2999 dbg("rtld_exit()"); 3000 objlist_call_fini(&list_fini, NULL, &lockstate); 3001 /* No need to remove the items from the list, since we are exiting. */ 3002 if (!libmap_disable) 3003 lm_fini(); 3004 lock_release(rtld_bind_lock, &lockstate); 3005 } 3006 3007 /* 3008 * Iterate over a search path, translate each element, and invoke the 3009 * callback on the result. 3010 */ 3011 static void * 3012 path_enumerate(const char *path, path_enum_proc callback, 3013 const char *refobj_path, void *arg) 3014 { 3015 const char *trans; 3016 if (path == NULL) 3017 return (NULL); 3018 3019 path += strspn(path, ":;"); 3020 while (*path != '\0') { 3021 size_t len; 3022 char *res; 3023 3024 len = strcspn(path, ":;"); 3025 trans = lm_findn(refobj_path, path, len); 3026 if (trans) 3027 res = callback(trans, strlen(trans), arg); 3028 else 3029 res = callback(path, len, arg); 3030 3031 if (res != NULL) 3032 return (res); 3033 3034 path += len; 3035 path += strspn(path, ":;"); 3036 } 3037 3038 return (NULL); 3039 } 3040 3041 struct try_library_args { 3042 const char *name; 3043 size_t namelen; 3044 char *buffer; 3045 size_t buflen; 3046 int fd; 3047 }; 3048 3049 static void * 3050 try_library_path(const char *dir, size_t dirlen, void *param) 3051 { 3052 struct try_library_args *arg; 3053 int fd; 3054 3055 arg = param; 3056 if (*dir == '/' || trust) { 3057 char *pathname; 3058 3059 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3060 return (NULL); 3061 3062 pathname = arg->buffer; 3063 strncpy(pathname, dir, dirlen); 3064 pathname[dirlen] = '/'; 3065 strcpy(pathname + dirlen + 1, arg->name); 3066 3067 dbg(" Trying \"%s\"", pathname); 3068 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3069 if (fd >= 0) { 3070 dbg(" Opened \"%s\", fd %d", pathname, fd); 3071 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3072 strcpy(pathname, arg->buffer); 3073 arg->fd = fd; 3074 return (pathname); 3075 } else { 3076 dbg(" Failed to open \"%s\": %s", 3077 pathname, rtld_strerror(errno)); 3078 } 3079 } 3080 return (NULL); 3081 } 3082 3083 static char * 3084 search_library_path(const char *name, const char *path, 3085 const char *refobj_path, int *fdp) 3086 { 3087 char *p; 3088 struct try_library_args arg; 3089 3090 if (path == NULL) 3091 return NULL; 3092 3093 arg.name = name; 3094 arg.namelen = strlen(name); 3095 arg.buffer = xmalloc(PATH_MAX); 3096 arg.buflen = PATH_MAX; 3097 arg.fd = -1; 3098 3099 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3100 *fdp = arg.fd; 3101 3102 free(arg.buffer); 3103 3104 return (p); 3105 } 3106 3107 3108 /* 3109 * Finds the library with the given name using the directory descriptors 3110 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3111 * 3112 * Returns a freshly-opened close-on-exec file descriptor for the library, 3113 * or -1 if the library cannot be found. 3114 */ 3115 static char * 3116 search_library_pathfds(const char *name, const char *path, int *fdp) 3117 { 3118 char *envcopy, *fdstr, *found, *last_token; 3119 size_t len; 3120 int dirfd, fd; 3121 3122 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3123 3124 /* Don't load from user-specified libdirs into setuid binaries. */ 3125 if (!trust) 3126 return (NULL); 3127 3128 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3129 if (path == NULL) 3130 return (NULL); 3131 3132 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3133 if (name[0] == '/') { 3134 dbg("Absolute path (%s) passed to %s", name, __func__); 3135 return (NULL); 3136 } 3137 3138 /* 3139 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3140 * copy of the path, as strtok_r rewrites separator tokens 3141 * with '\0'. 3142 */ 3143 found = NULL; 3144 envcopy = xstrdup(path); 3145 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3146 fdstr = strtok_r(NULL, ":", &last_token)) { 3147 dirfd = parse_integer(fdstr); 3148 if (dirfd < 0) { 3149 _rtld_error("failed to parse directory FD: '%s'", 3150 fdstr); 3151 break; 3152 } 3153 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3154 if (fd >= 0) { 3155 *fdp = fd; 3156 len = strlen(fdstr) + strlen(name) + 3; 3157 found = xmalloc(len); 3158 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3159 _rtld_error("error generating '%d/%s'", 3160 dirfd, name); 3161 rtld_die(); 3162 } 3163 dbg("open('%s') => %d", found, fd); 3164 break; 3165 } 3166 } 3167 free(envcopy); 3168 3169 return (found); 3170 } 3171 3172 3173 int 3174 dlclose(void *handle) 3175 { 3176 RtldLockState lockstate; 3177 int error; 3178 3179 wlock_acquire(rtld_bind_lock, &lockstate); 3180 error = dlclose_locked(handle, &lockstate); 3181 lock_release(rtld_bind_lock, &lockstate); 3182 return (error); 3183 } 3184 3185 static int 3186 dlclose_locked(void *handle, RtldLockState *lockstate) 3187 { 3188 Obj_Entry *root; 3189 3190 root = dlcheck(handle); 3191 if (root == NULL) 3192 return -1; 3193 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3194 root->path); 3195 3196 /* Unreference the object and its dependencies. */ 3197 root->dl_refcount--; 3198 3199 if (root->refcount == 1) { 3200 /* 3201 * The object will be no longer referenced, so we must unload it. 3202 * First, call the fini functions. 3203 */ 3204 objlist_call_fini(&list_fini, root, lockstate); 3205 3206 unref_dag(root); 3207 3208 /* Finish cleaning up the newly-unreferenced objects. */ 3209 GDB_STATE(RT_DELETE,&root->linkmap); 3210 unload_object(root, lockstate); 3211 GDB_STATE(RT_CONSISTENT,NULL); 3212 } else 3213 unref_dag(root); 3214 3215 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3216 return 0; 3217 } 3218 3219 char * 3220 dlerror(void) 3221 { 3222 char *msg = error_message; 3223 error_message = NULL; 3224 return msg; 3225 } 3226 3227 /* 3228 * This function is deprecated and has no effect. 3229 */ 3230 void 3231 dllockinit(void *context, 3232 void *(*_lock_create)(void *context) __unused, 3233 void (*_rlock_acquire)(void *lock) __unused, 3234 void (*_wlock_acquire)(void *lock) __unused, 3235 void (*_lock_release)(void *lock) __unused, 3236 void (*_lock_destroy)(void *lock) __unused, 3237 void (*context_destroy)(void *context)) 3238 { 3239 static void *cur_context; 3240 static void (*cur_context_destroy)(void *); 3241 3242 /* Just destroy the context from the previous call, if necessary. */ 3243 if (cur_context_destroy != NULL) 3244 cur_context_destroy(cur_context); 3245 cur_context = context; 3246 cur_context_destroy = context_destroy; 3247 } 3248 3249 void * 3250 dlopen(const char *name, int mode) 3251 { 3252 3253 return (rtld_dlopen(name, -1, mode)); 3254 } 3255 3256 void * 3257 fdlopen(int fd, int mode) 3258 { 3259 3260 return (rtld_dlopen(NULL, fd, mode)); 3261 } 3262 3263 static void * 3264 rtld_dlopen(const char *name, int fd, int mode) 3265 { 3266 RtldLockState lockstate; 3267 int lo_flags; 3268 3269 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3270 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3271 if (ld_tracing != NULL) { 3272 rlock_acquire(rtld_bind_lock, &lockstate); 3273 if (sigsetjmp(lockstate.env, 0) != 0) 3274 lock_upgrade(rtld_bind_lock, &lockstate); 3275 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3276 lock_release(rtld_bind_lock, &lockstate); 3277 } 3278 lo_flags = RTLD_LO_DLOPEN; 3279 if (mode & RTLD_NODELETE) 3280 lo_flags |= RTLD_LO_NODELETE; 3281 if (mode & RTLD_NOLOAD) 3282 lo_flags |= RTLD_LO_NOLOAD; 3283 if (ld_tracing != NULL) 3284 lo_flags |= RTLD_LO_TRACE; 3285 3286 return (dlopen_object(name, fd, obj_main, lo_flags, 3287 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3288 } 3289 3290 static void 3291 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3292 { 3293 3294 obj->dl_refcount--; 3295 unref_dag(obj); 3296 if (obj->refcount == 0) 3297 unload_object(obj, lockstate); 3298 } 3299 3300 static Obj_Entry * 3301 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3302 int mode, RtldLockState *lockstate) 3303 { 3304 Obj_Entry *old_obj_tail; 3305 Obj_Entry *obj; 3306 Objlist initlist; 3307 RtldLockState mlockstate; 3308 int result; 3309 3310 objlist_init(&initlist); 3311 3312 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3313 wlock_acquire(rtld_bind_lock, &mlockstate); 3314 lockstate = &mlockstate; 3315 } 3316 GDB_STATE(RT_ADD,NULL); 3317 3318 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3319 obj = NULL; 3320 if (name == NULL && fd == -1) { 3321 obj = obj_main; 3322 obj->refcount++; 3323 } else { 3324 obj = load_object(name, fd, refobj, lo_flags); 3325 } 3326 3327 if (obj) { 3328 obj->dl_refcount++; 3329 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3330 objlist_push_tail(&list_global, obj); 3331 if (globallist_next(old_obj_tail) != NULL) { 3332 /* We loaded something new. */ 3333 assert(globallist_next(old_obj_tail) == obj); 3334 result = 0; 3335 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3336 !allocate_tls_offset(obj)) { 3337 _rtld_error("%s: No space available " 3338 "for static Thread Local Storage", obj->path); 3339 result = -1; 3340 } 3341 if (result != -1) 3342 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3343 RTLD_LO_EARLY)); 3344 init_dag(obj); 3345 ref_dag(obj); 3346 if (result != -1) 3347 result = rtld_verify_versions(&obj->dagmembers); 3348 if (result != -1 && ld_tracing) 3349 goto trace; 3350 if (result == -1 || relocate_object_dag(obj, 3351 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3352 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3353 lockstate) == -1) { 3354 dlopen_cleanup(obj, lockstate); 3355 obj = NULL; 3356 } else if (lo_flags & RTLD_LO_EARLY) { 3357 /* 3358 * Do not call the init functions for early loaded 3359 * filtees. The image is still not initialized enough 3360 * for them to work. 3361 * 3362 * Our object is found by the global object list and 3363 * will be ordered among all init calls done right 3364 * before transferring control to main. 3365 */ 3366 } else { 3367 /* Make list of init functions to call. */ 3368 initlist_add_objects(obj, obj, &initlist); 3369 } 3370 /* 3371 * Process all no_delete or global objects here, given 3372 * them own DAGs to prevent their dependencies from being 3373 * unloaded. This has to be done after we have loaded all 3374 * of the dependencies, so that we do not miss any. 3375 */ 3376 if (obj != NULL) 3377 process_z(obj); 3378 } else { 3379 /* 3380 * Bump the reference counts for objects on this DAG. If 3381 * this is the first dlopen() call for the object that was 3382 * already loaded as a dependency, initialize the dag 3383 * starting at it. 3384 */ 3385 init_dag(obj); 3386 ref_dag(obj); 3387 3388 if ((lo_flags & RTLD_LO_TRACE) != 0) 3389 goto trace; 3390 } 3391 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3392 obj->z_nodelete) && !obj->ref_nodel) { 3393 dbg("obj %s nodelete", obj->path); 3394 ref_dag(obj); 3395 obj->z_nodelete = obj->ref_nodel = true; 3396 } 3397 } 3398 3399 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3400 name); 3401 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3402 3403 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3404 map_stacks_exec(lockstate); 3405 if (obj != NULL) 3406 distribute_static_tls(&initlist, lockstate); 3407 } 3408 3409 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3410 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3411 lockstate) == -1) { 3412 objlist_clear(&initlist); 3413 dlopen_cleanup(obj, lockstate); 3414 if (lockstate == &mlockstate) 3415 lock_release(rtld_bind_lock, lockstate); 3416 return (NULL); 3417 } 3418 3419 if (!(lo_flags & RTLD_LO_EARLY)) { 3420 /* Call the init functions. */ 3421 objlist_call_init(&initlist, lockstate); 3422 } 3423 objlist_clear(&initlist); 3424 if (lockstate == &mlockstate) 3425 lock_release(rtld_bind_lock, lockstate); 3426 return obj; 3427 trace: 3428 trace_loaded_objects(obj); 3429 if (lockstate == &mlockstate) 3430 lock_release(rtld_bind_lock, lockstate); 3431 exit(0); 3432 } 3433 3434 static void * 3435 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3436 int flags) 3437 { 3438 DoneList donelist; 3439 const Obj_Entry *obj, *defobj; 3440 const Elf_Sym *def; 3441 SymLook req; 3442 RtldLockState lockstate; 3443 tls_index ti; 3444 void *sym; 3445 int res; 3446 3447 def = NULL; 3448 defobj = NULL; 3449 symlook_init(&req, name); 3450 req.ventry = ve; 3451 req.flags = flags | SYMLOOK_IN_PLT; 3452 req.lockstate = &lockstate; 3453 3454 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3455 rlock_acquire(rtld_bind_lock, &lockstate); 3456 if (sigsetjmp(lockstate.env, 0) != 0) 3457 lock_upgrade(rtld_bind_lock, &lockstate); 3458 if (handle == NULL || handle == RTLD_NEXT || 3459 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3460 3461 if ((obj = obj_from_addr(retaddr)) == NULL) { 3462 _rtld_error("Cannot determine caller's shared object"); 3463 lock_release(rtld_bind_lock, &lockstate); 3464 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3465 return NULL; 3466 } 3467 if (handle == NULL) { /* Just the caller's shared object. */ 3468 res = symlook_obj(&req, obj); 3469 if (res == 0) { 3470 def = req.sym_out; 3471 defobj = req.defobj_out; 3472 } 3473 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3474 handle == RTLD_SELF) { /* ... caller included */ 3475 if (handle == RTLD_NEXT) 3476 obj = globallist_next(obj); 3477 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3478 if (obj->marker) 3479 continue; 3480 res = symlook_obj(&req, obj); 3481 if (res == 0) { 3482 if (def == NULL || 3483 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3484 def = req.sym_out; 3485 defobj = req.defobj_out; 3486 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3487 break; 3488 } 3489 } 3490 } 3491 /* 3492 * Search the dynamic linker itself, and possibly resolve the 3493 * symbol from there. This is how the application links to 3494 * dynamic linker services such as dlopen. 3495 */ 3496 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3497 res = symlook_obj(&req, &obj_rtld); 3498 if (res == 0) { 3499 def = req.sym_out; 3500 defobj = req.defobj_out; 3501 } 3502 } 3503 } else { 3504 assert(handle == RTLD_DEFAULT); 3505 res = symlook_default(&req, obj); 3506 if (res == 0) { 3507 defobj = req.defobj_out; 3508 def = req.sym_out; 3509 } 3510 } 3511 } else { 3512 if ((obj = dlcheck(handle)) == NULL) { 3513 lock_release(rtld_bind_lock, &lockstate); 3514 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3515 return NULL; 3516 } 3517 3518 donelist_init(&donelist); 3519 if (obj->mainprog) { 3520 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3521 res = symlook_global(&req, &donelist); 3522 if (res == 0) { 3523 def = req.sym_out; 3524 defobj = req.defobj_out; 3525 } 3526 /* 3527 * Search the dynamic linker itself, and possibly resolve the 3528 * symbol from there. This is how the application links to 3529 * dynamic linker services such as dlopen. 3530 */ 3531 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3532 res = symlook_obj(&req, &obj_rtld); 3533 if (res == 0) { 3534 def = req.sym_out; 3535 defobj = req.defobj_out; 3536 } 3537 } 3538 } 3539 else { 3540 /* Search the whole DAG rooted at the given object. */ 3541 res = symlook_list(&req, &obj->dagmembers, &donelist); 3542 if (res == 0) { 3543 def = req.sym_out; 3544 defobj = req.defobj_out; 3545 } 3546 } 3547 } 3548 3549 if (def != NULL) { 3550 lock_release(rtld_bind_lock, &lockstate); 3551 3552 /* 3553 * The value required by the caller is derived from the value 3554 * of the symbol. this is simply the relocated value of the 3555 * symbol. 3556 */ 3557 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3558 sym = make_function_pointer(def, defobj); 3559 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3560 sym = rtld_resolve_ifunc(defobj, def); 3561 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3562 ti.ti_module = defobj->tlsindex; 3563 ti.ti_offset = def->st_value; 3564 sym = __tls_get_addr(&ti); 3565 } else 3566 sym = defobj->relocbase + def->st_value; 3567 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3568 return (sym); 3569 } 3570 3571 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3572 ve != NULL ? ve->name : ""); 3573 lock_release(rtld_bind_lock, &lockstate); 3574 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3575 return NULL; 3576 } 3577 3578 void * 3579 dlsym(void *handle, const char *name) 3580 { 3581 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3582 SYMLOOK_DLSYM); 3583 } 3584 3585 dlfunc_t 3586 dlfunc(void *handle, const char *name) 3587 { 3588 union { 3589 void *d; 3590 dlfunc_t f; 3591 } rv; 3592 3593 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3594 SYMLOOK_DLSYM); 3595 return (rv.f); 3596 } 3597 3598 void * 3599 dlvsym(void *handle, const char *name, const char *version) 3600 { 3601 Ver_Entry ventry; 3602 3603 ventry.name = version; 3604 ventry.file = NULL; 3605 ventry.hash = elf_hash(version); 3606 ventry.flags= 0; 3607 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3608 SYMLOOK_DLSYM); 3609 } 3610 3611 int 3612 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3613 { 3614 const Obj_Entry *obj; 3615 RtldLockState lockstate; 3616 3617 rlock_acquire(rtld_bind_lock, &lockstate); 3618 obj = obj_from_addr(addr); 3619 if (obj == NULL) { 3620 _rtld_error("No shared object contains address"); 3621 lock_release(rtld_bind_lock, &lockstate); 3622 return (0); 3623 } 3624 rtld_fill_dl_phdr_info(obj, phdr_info); 3625 lock_release(rtld_bind_lock, &lockstate); 3626 return (1); 3627 } 3628 3629 int 3630 dladdr(const void *addr, Dl_info *info) 3631 { 3632 const Obj_Entry *obj; 3633 const Elf_Sym *def; 3634 void *symbol_addr; 3635 unsigned long symoffset; 3636 RtldLockState lockstate; 3637 3638 rlock_acquire(rtld_bind_lock, &lockstate); 3639 obj = obj_from_addr(addr); 3640 if (obj == NULL) { 3641 _rtld_error("No shared object contains address"); 3642 lock_release(rtld_bind_lock, &lockstate); 3643 return 0; 3644 } 3645 info->dli_fname = obj->path; 3646 info->dli_fbase = obj->mapbase; 3647 info->dli_saddr = (void *)0; 3648 info->dli_sname = NULL; 3649 3650 /* 3651 * Walk the symbol list looking for the symbol whose address is 3652 * closest to the address sent in. 3653 */ 3654 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3655 def = obj->symtab + symoffset; 3656 3657 /* 3658 * For skip the symbol if st_shndx is either SHN_UNDEF or 3659 * SHN_COMMON. 3660 */ 3661 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3662 continue; 3663 3664 /* 3665 * If the symbol is greater than the specified address, or if it 3666 * is further away from addr than the current nearest symbol, 3667 * then reject it. 3668 */ 3669 symbol_addr = obj->relocbase + def->st_value; 3670 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3671 continue; 3672 3673 /* Update our idea of the nearest symbol. */ 3674 info->dli_sname = obj->strtab + def->st_name; 3675 info->dli_saddr = symbol_addr; 3676 3677 /* Exact match? */ 3678 if (info->dli_saddr == addr) 3679 break; 3680 } 3681 lock_release(rtld_bind_lock, &lockstate); 3682 return 1; 3683 } 3684 3685 int 3686 dlinfo(void *handle, int request, void *p) 3687 { 3688 const Obj_Entry *obj; 3689 RtldLockState lockstate; 3690 int error; 3691 3692 rlock_acquire(rtld_bind_lock, &lockstate); 3693 3694 if (handle == NULL || handle == RTLD_SELF) { 3695 void *retaddr; 3696 3697 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3698 if ((obj = obj_from_addr(retaddr)) == NULL) 3699 _rtld_error("Cannot determine caller's shared object"); 3700 } else 3701 obj = dlcheck(handle); 3702 3703 if (obj == NULL) { 3704 lock_release(rtld_bind_lock, &lockstate); 3705 return (-1); 3706 } 3707 3708 error = 0; 3709 switch (request) { 3710 case RTLD_DI_LINKMAP: 3711 *((struct link_map const **)p) = &obj->linkmap; 3712 break; 3713 case RTLD_DI_ORIGIN: 3714 error = rtld_dirname(obj->path, p); 3715 break; 3716 3717 case RTLD_DI_SERINFOSIZE: 3718 case RTLD_DI_SERINFO: 3719 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3720 break; 3721 3722 default: 3723 _rtld_error("Invalid request %d passed to dlinfo()", request); 3724 error = -1; 3725 } 3726 3727 lock_release(rtld_bind_lock, &lockstate); 3728 3729 return (error); 3730 } 3731 3732 static void 3733 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3734 { 3735 3736 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3737 phdr_info->dlpi_name = obj->path; 3738 phdr_info->dlpi_phdr = obj->phdr; 3739 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3740 phdr_info->dlpi_tls_modid = obj->tlsindex; 3741 phdr_info->dlpi_tls_data = obj->tlsinit; 3742 phdr_info->dlpi_adds = obj_loads; 3743 phdr_info->dlpi_subs = obj_loads - obj_count; 3744 } 3745 3746 int 3747 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3748 { 3749 struct dl_phdr_info phdr_info; 3750 Obj_Entry *obj, marker; 3751 RtldLockState bind_lockstate, phdr_lockstate; 3752 int error; 3753 3754 init_marker(&marker); 3755 error = 0; 3756 3757 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3758 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3759 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3760 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3761 rtld_fill_dl_phdr_info(obj, &phdr_info); 3762 hold_object(obj); 3763 lock_release(rtld_bind_lock, &bind_lockstate); 3764 3765 error = callback(&phdr_info, sizeof phdr_info, param); 3766 3767 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3768 unhold_object(obj); 3769 obj = globallist_next(&marker); 3770 TAILQ_REMOVE(&obj_list, &marker, next); 3771 if (error != 0) { 3772 lock_release(rtld_bind_lock, &bind_lockstate); 3773 lock_release(rtld_phdr_lock, &phdr_lockstate); 3774 return (error); 3775 } 3776 } 3777 3778 if (error == 0) { 3779 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3780 lock_release(rtld_bind_lock, &bind_lockstate); 3781 error = callback(&phdr_info, sizeof(phdr_info), param); 3782 } 3783 lock_release(rtld_phdr_lock, &phdr_lockstate); 3784 return (error); 3785 } 3786 3787 static void * 3788 fill_search_info(const char *dir, size_t dirlen, void *param) 3789 { 3790 struct fill_search_info_args *arg; 3791 3792 arg = param; 3793 3794 if (arg->request == RTLD_DI_SERINFOSIZE) { 3795 arg->serinfo->dls_cnt ++; 3796 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3797 } else { 3798 struct dl_serpath *s_entry; 3799 3800 s_entry = arg->serpath; 3801 s_entry->dls_name = arg->strspace; 3802 s_entry->dls_flags = arg->flags; 3803 3804 strncpy(arg->strspace, dir, dirlen); 3805 arg->strspace[dirlen] = '\0'; 3806 3807 arg->strspace += dirlen + 1; 3808 arg->serpath++; 3809 } 3810 3811 return (NULL); 3812 } 3813 3814 static int 3815 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3816 { 3817 struct dl_serinfo _info; 3818 struct fill_search_info_args args; 3819 3820 args.request = RTLD_DI_SERINFOSIZE; 3821 args.serinfo = &_info; 3822 3823 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3824 _info.dls_cnt = 0; 3825 3826 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3827 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3828 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3829 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3830 if (!obj->z_nodeflib) 3831 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3832 3833 3834 if (request == RTLD_DI_SERINFOSIZE) { 3835 info->dls_size = _info.dls_size; 3836 info->dls_cnt = _info.dls_cnt; 3837 return (0); 3838 } 3839 3840 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3841 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3842 return (-1); 3843 } 3844 3845 args.request = RTLD_DI_SERINFO; 3846 args.serinfo = info; 3847 args.serpath = &info->dls_serpath[0]; 3848 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3849 3850 args.flags = LA_SER_RUNPATH; 3851 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3852 return (-1); 3853 3854 args.flags = LA_SER_LIBPATH; 3855 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3856 return (-1); 3857 3858 args.flags = LA_SER_RUNPATH; 3859 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3860 return (-1); 3861 3862 args.flags = LA_SER_CONFIG; 3863 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3864 != NULL) 3865 return (-1); 3866 3867 args.flags = LA_SER_DEFAULT; 3868 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3869 fill_search_info, NULL, &args) != NULL) 3870 return (-1); 3871 return (0); 3872 } 3873 3874 static int 3875 rtld_dirname(const char *path, char *bname) 3876 { 3877 const char *endp; 3878 3879 /* Empty or NULL string gets treated as "." */ 3880 if (path == NULL || *path == '\0') { 3881 bname[0] = '.'; 3882 bname[1] = '\0'; 3883 return (0); 3884 } 3885 3886 /* Strip trailing slashes */ 3887 endp = path + strlen(path) - 1; 3888 while (endp > path && *endp == '/') 3889 endp--; 3890 3891 /* Find the start of the dir */ 3892 while (endp > path && *endp != '/') 3893 endp--; 3894 3895 /* Either the dir is "/" or there are no slashes */ 3896 if (endp == path) { 3897 bname[0] = *endp == '/' ? '/' : '.'; 3898 bname[1] = '\0'; 3899 return (0); 3900 } else { 3901 do { 3902 endp--; 3903 } while (endp > path && *endp == '/'); 3904 } 3905 3906 if (endp - path + 2 > PATH_MAX) 3907 { 3908 _rtld_error("Filename is too long: %s", path); 3909 return(-1); 3910 } 3911 3912 strncpy(bname, path, endp - path + 1); 3913 bname[endp - path + 1] = '\0'; 3914 return (0); 3915 } 3916 3917 static int 3918 rtld_dirname_abs(const char *path, char *base) 3919 { 3920 char *last; 3921 3922 if (realpath(path, base) == NULL) 3923 return (-1); 3924 dbg("%s -> %s", path, base); 3925 last = strrchr(base, '/'); 3926 if (last == NULL) 3927 return (-1); 3928 if (last != base) 3929 *last = '\0'; 3930 return (0); 3931 } 3932 3933 static void 3934 linkmap_add(Obj_Entry *obj) 3935 { 3936 struct link_map *l = &obj->linkmap; 3937 struct link_map *prev; 3938 3939 obj->linkmap.l_name = obj->path; 3940 obj->linkmap.l_addr = obj->mapbase; 3941 obj->linkmap.l_ld = obj->dynamic; 3942 #ifdef __mips__ 3943 /* GDB needs load offset on MIPS to use the symbols */ 3944 obj->linkmap.l_offs = obj->relocbase; 3945 #endif 3946 3947 if (r_debug.r_map == NULL) { 3948 r_debug.r_map = l; 3949 return; 3950 } 3951 3952 /* 3953 * Scan to the end of the list, but not past the entry for the 3954 * dynamic linker, which we want to keep at the very end. 3955 */ 3956 for (prev = r_debug.r_map; 3957 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3958 prev = prev->l_next) 3959 ; 3960 3961 /* Link in the new entry. */ 3962 l->l_prev = prev; 3963 l->l_next = prev->l_next; 3964 if (l->l_next != NULL) 3965 l->l_next->l_prev = l; 3966 prev->l_next = l; 3967 } 3968 3969 static void 3970 linkmap_delete(Obj_Entry *obj) 3971 { 3972 struct link_map *l = &obj->linkmap; 3973 3974 if (l->l_prev == NULL) { 3975 if ((r_debug.r_map = l->l_next) != NULL) 3976 l->l_next->l_prev = NULL; 3977 return; 3978 } 3979 3980 if ((l->l_prev->l_next = l->l_next) != NULL) 3981 l->l_next->l_prev = l->l_prev; 3982 } 3983 3984 /* 3985 * Function for the debugger to set a breakpoint on to gain control. 3986 * 3987 * The two parameters allow the debugger to easily find and determine 3988 * what the runtime loader is doing and to whom it is doing it. 3989 * 3990 * When the loadhook trap is hit (r_debug_state, set at program 3991 * initialization), the arguments can be found on the stack: 3992 * 3993 * +8 struct link_map *m 3994 * +4 struct r_debug *rd 3995 * +0 RetAddr 3996 */ 3997 void 3998 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 3999 { 4000 /* 4001 * The following is a hack to force the compiler to emit calls to 4002 * this function, even when optimizing. If the function is empty, 4003 * the compiler is not obliged to emit any code for calls to it, 4004 * even when marked __noinline. However, gdb depends on those 4005 * calls being made. 4006 */ 4007 __compiler_membar(); 4008 } 4009 4010 /* 4011 * A function called after init routines have completed. This can be used to 4012 * break before a program's entry routine is called, and can be used when 4013 * main is not available in the symbol table. 4014 */ 4015 void 4016 _r_debug_postinit(struct link_map *m __unused) 4017 { 4018 4019 /* See r_debug_state(). */ 4020 __compiler_membar(); 4021 } 4022 4023 static void 4024 release_object(Obj_Entry *obj) 4025 { 4026 4027 if (obj->holdcount > 0) { 4028 obj->unholdfree = true; 4029 return; 4030 } 4031 munmap(obj->mapbase, obj->mapsize); 4032 linkmap_delete(obj); 4033 obj_free(obj); 4034 } 4035 4036 /* 4037 * Get address of the pointer variable in the main program. 4038 * Prefer non-weak symbol over the weak one. 4039 */ 4040 static const void ** 4041 get_program_var_addr(const char *name, RtldLockState *lockstate) 4042 { 4043 SymLook req; 4044 DoneList donelist; 4045 4046 symlook_init(&req, name); 4047 req.lockstate = lockstate; 4048 donelist_init(&donelist); 4049 if (symlook_global(&req, &donelist) != 0) 4050 return (NULL); 4051 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4052 return ((const void **)make_function_pointer(req.sym_out, 4053 req.defobj_out)); 4054 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4055 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4056 else 4057 return ((const void **)(req.defobj_out->relocbase + 4058 req.sym_out->st_value)); 4059 } 4060 4061 /* 4062 * Set a pointer variable in the main program to the given value. This 4063 * is used to set key variables such as "environ" before any of the 4064 * init functions are called. 4065 */ 4066 static void 4067 set_program_var(const char *name, const void *value) 4068 { 4069 const void **addr; 4070 4071 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4072 dbg("\"%s\": *%p <-- %p", name, addr, value); 4073 *addr = value; 4074 } 4075 } 4076 4077 /* 4078 * Search the global objects, including dependencies and main object, 4079 * for the given symbol. 4080 */ 4081 static int 4082 symlook_global(SymLook *req, DoneList *donelist) 4083 { 4084 SymLook req1; 4085 const Objlist_Entry *elm; 4086 int res; 4087 4088 symlook_init_from_req(&req1, req); 4089 4090 /* Search all objects loaded at program start up. */ 4091 if (req->defobj_out == NULL || 4092 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4093 res = symlook_list(&req1, &list_main, donelist); 4094 if (res == 0 && (req->defobj_out == NULL || 4095 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4096 req->sym_out = req1.sym_out; 4097 req->defobj_out = req1.defobj_out; 4098 assert(req->defobj_out != NULL); 4099 } 4100 } 4101 4102 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4103 STAILQ_FOREACH(elm, &list_global, link) { 4104 if (req->defobj_out != NULL && 4105 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4106 break; 4107 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4108 if (res == 0 && (req->defobj_out == NULL || 4109 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4110 req->sym_out = req1.sym_out; 4111 req->defobj_out = req1.defobj_out; 4112 assert(req->defobj_out != NULL); 4113 } 4114 } 4115 4116 return (req->sym_out != NULL ? 0 : ESRCH); 4117 } 4118 4119 /* 4120 * Given a symbol name in a referencing object, find the corresponding 4121 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4122 * no definition was found. Returns a pointer to the Obj_Entry of the 4123 * defining object via the reference parameter DEFOBJ_OUT. 4124 */ 4125 static int 4126 symlook_default(SymLook *req, const Obj_Entry *refobj) 4127 { 4128 DoneList donelist; 4129 const Objlist_Entry *elm; 4130 SymLook req1; 4131 int res; 4132 4133 donelist_init(&donelist); 4134 symlook_init_from_req(&req1, req); 4135 4136 /* 4137 * Look first in the referencing object if linked symbolically, 4138 * and similarly handle protected symbols. 4139 */ 4140 res = symlook_obj(&req1, refobj); 4141 if (res == 0 && (refobj->symbolic || 4142 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4143 req->sym_out = req1.sym_out; 4144 req->defobj_out = req1.defobj_out; 4145 assert(req->defobj_out != NULL); 4146 } 4147 if (refobj->symbolic || req->defobj_out != NULL) 4148 donelist_check(&donelist, refobj); 4149 4150 symlook_global(req, &donelist); 4151 4152 /* Search all dlopened DAGs containing the referencing object. */ 4153 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4154 if (req->sym_out != NULL && 4155 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4156 break; 4157 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4158 if (res == 0 && (req->sym_out == NULL || 4159 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4160 req->sym_out = req1.sym_out; 4161 req->defobj_out = req1.defobj_out; 4162 assert(req->defobj_out != NULL); 4163 } 4164 } 4165 4166 /* 4167 * Search the dynamic linker itself, and possibly resolve the 4168 * symbol from there. This is how the application links to 4169 * dynamic linker services such as dlopen. 4170 */ 4171 if (req->sym_out == NULL || 4172 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4173 res = symlook_obj(&req1, &obj_rtld); 4174 if (res == 0) { 4175 req->sym_out = req1.sym_out; 4176 req->defobj_out = req1.defobj_out; 4177 assert(req->defobj_out != NULL); 4178 } 4179 } 4180 4181 return (req->sym_out != NULL ? 0 : ESRCH); 4182 } 4183 4184 static int 4185 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4186 { 4187 const Elf_Sym *def; 4188 const Obj_Entry *defobj; 4189 const Objlist_Entry *elm; 4190 SymLook req1; 4191 int res; 4192 4193 def = NULL; 4194 defobj = NULL; 4195 STAILQ_FOREACH(elm, objlist, link) { 4196 if (donelist_check(dlp, elm->obj)) 4197 continue; 4198 symlook_init_from_req(&req1, req); 4199 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4200 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4201 def = req1.sym_out; 4202 defobj = req1.defobj_out; 4203 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4204 break; 4205 } 4206 } 4207 } 4208 if (def != NULL) { 4209 req->sym_out = def; 4210 req->defobj_out = defobj; 4211 return (0); 4212 } 4213 return (ESRCH); 4214 } 4215 4216 /* 4217 * Search the chain of DAGS cointed to by the given Needed_Entry 4218 * for a symbol of the given name. Each DAG is scanned completely 4219 * before advancing to the next one. Returns a pointer to the symbol, 4220 * or NULL if no definition was found. 4221 */ 4222 static int 4223 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4224 { 4225 const Elf_Sym *def; 4226 const Needed_Entry *n; 4227 const Obj_Entry *defobj; 4228 SymLook req1; 4229 int res; 4230 4231 def = NULL; 4232 defobj = NULL; 4233 symlook_init_from_req(&req1, req); 4234 for (n = needed; n != NULL; n = n->next) { 4235 if (n->obj == NULL || 4236 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4237 continue; 4238 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4239 def = req1.sym_out; 4240 defobj = req1.defobj_out; 4241 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4242 break; 4243 } 4244 } 4245 if (def != NULL) { 4246 req->sym_out = def; 4247 req->defobj_out = defobj; 4248 return (0); 4249 } 4250 return (ESRCH); 4251 } 4252 4253 /* 4254 * Search the symbol table of a single shared object for a symbol of 4255 * the given name and version, if requested. Returns a pointer to the 4256 * symbol, or NULL if no definition was found. If the object is 4257 * filter, return filtered symbol from filtee. 4258 * 4259 * The symbol's hash value is passed in for efficiency reasons; that 4260 * eliminates many recomputations of the hash value. 4261 */ 4262 int 4263 symlook_obj(SymLook *req, const Obj_Entry *obj) 4264 { 4265 DoneList donelist; 4266 SymLook req1; 4267 int flags, res, mres; 4268 4269 /* 4270 * If there is at least one valid hash at this point, we prefer to 4271 * use the faster GNU version if available. 4272 */ 4273 if (obj->valid_hash_gnu) 4274 mres = symlook_obj1_gnu(req, obj); 4275 else if (obj->valid_hash_sysv) 4276 mres = symlook_obj1_sysv(req, obj); 4277 else 4278 return (EINVAL); 4279 4280 if (mres == 0) { 4281 if (obj->needed_filtees != NULL) { 4282 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4283 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4284 donelist_init(&donelist); 4285 symlook_init_from_req(&req1, req); 4286 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4287 if (res == 0) { 4288 req->sym_out = req1.sym_out; 4289 req->defobj_out = req1.defobj_out; 4290 } 4291 return (res); 4292 } 4293 if (obj->needed_aux_filtees != NULL) { 4294 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4295 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4296 donelist_init(&donelist); 4297 symlook_init_from_req(&req1, req); 4298 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4299 if (res == 0) { 4300 req->sym_out = req1.sym_out; 4301 req->defobj_out = req1.defobj_out; 4302 return (res); 4303 } 4304 } 4305 } 4306 return (mres); 4307 } 4308 4309 /* Symbol match routine common to both hash functions */ 4310 static bool 4311 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4312 const unsigned long symnum) 4313 { 4314 Elf_Versym verndx; 4315 const Elf_Sym *symp; 4316 const char *strp; 4317 4318 symp = obj->symtab + symnum; 4319 strp = obj->strtab + symp->st_name; 4320 4321 switch (ELF_ST_TYPE(symp->st_info)) { 4322 case STT_FUNC: 4323 case STT_NOTYPE: 4324 case STT_OBJECT: 4325 case STT_COMMON: 4326 case STT_GNU_IFUNC: 4327 if (symp->st_value == 0) 4328 return (false); 4329 /* fallthrough */ 4330 case STT_TLS: 4331 if (symp->st_shndx != SHN_UNDEF) 4332 break; 4333 #ifndef __mips__ 4334 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4335 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4336 break; 4337 #endif 4338 /* fallthrough */ 4339 default: 4340 return (false); 4341 } 4342 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4343 return (false); 4344 4345 if (req->ventry == NULL) { 4346 if (obj->versyms != NULL) { 4347 verndx = VER_NDX(obj->versyms[symnum]); 4348 if (verndx > obj->vernum) { 4349 _rtld_error( 4350 "%s: symbol %s references wrong version %d", 4351 obj->path, obj->strtab + symnum, verndx); 4352 return (false); 4353 } 4354 /* 4355 * If we are not called from dlsym (i.e. this 4356 * is a normal relocation from unversioned 4357 * binary), accept the symbol immediately if 4358 * it happens to have first version after this 4359 * shared object became versioned. Otherwise, 4360 * if symbol is versioned and not hidden, 4361 * remember it. If it is the only symbol with 4362 * this name exported by the shared object, it 4363 * will be returned as a match by the calling 4364 * function. If symbol is global (verndx < 2) 4365 * accept it unconditionally. 4366 */ 4367 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4368 verndx == VER_NDX_GIVEN) { 4369 result->sym_out = symp; 4370 return (true); 4371 } 4372 else if (verndx >= VER_NDX_GIVEN) { 4373 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4374 == 0) { 4375 if (result->vsymp == NULL) 4376 result->vsymp = symp; 4377 result->vcount++; 4378 } 4379 return (false); 4380 } 4381 } 4382 result->sym_out = symp; 4383 return (true); 4384 } 4385 if (obj->versyms == NULL) { 4386 if (object_match_name(obj, req->ventry->name)) { 4387 _rtld_error("%s: object %s should provide version %s " 4388 "for symbol %s", obj_rtld.path, obj->path, 4389 req->ventry->name, obj->strtab + symnum); 4390 return (false); 4391 } 4392 } else { 4393 verndx = VER_NDX(obj->versyms[symnum]); 4394 if (verndx > obj->vernum) { 4395 _rtld_error("%s: symbol %s references wrong version %d", 4396 obj->path, obj->strtab + symnum, verndx); 4397 return (false); 4398 } 4399 if (obj->vertab[verndx].hash != req->ventry->hash || 4400 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4401 /* 4402 * Version does not match. Look if this is a 4403 * global symbol and if it is not hidden. If 4404 * global symbol (verndx < 2) is available, 4405 * use it. Do not return symbol if we are 4406 * called by dlvsym, because dlvsym looks for 4407 * a specific version and default one is not 4408 * what dlvsym wants. 4409 */ 4410 if ((req->flags & SYMLOOK_DLSYM) || 4411 (verndx >= VER_NDX_GIVEN) || 4412 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4413 return (false); 4414 } 4415 } 4416 result->sym_out = symp; 4417 return (true); 4418 } 4419 4420 /* 4421 * Search for symbol using SysV hash function. 4422 * obj->buckets is known not to be NULL at this point; the test for this was 4423 * performed with the obj->valid_hash_sysv assignment. 4424 */ 4425 static int 4426 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4427 { 4428 unsigned long symnum; 4429 Sym_Match_Result matchres; 4430 4431 matchres.sym_out = NULL; 4432 matchres.vsymp = NULL; 4433 matchres.vcount = 0; 4434 4435 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4436 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4437 if (symnum >= obj->nchains) 4438 return (ESRCH); /* Bad object */ 4439 4440 if (matched_symbol(req, obj, &matchres, symnum)) { 4441 req->sym_out = matchres.sym_out; 4442 req->defobj_out = obj; 4443 return (0); 4444 } 4445 } 4446 if (matchres.vcount == 1) { 4447 req->sym_out = matchres.vsymp; 4448 req->defobj_out = obj; 4449 return (0); 4450 } 4451 return (ESRCH); 4452 } 4453 4454 /* Search for symbol using GNU hash function */ 4455 static int 4456 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4457 { 4458 Elf_Addr bloom_word; 4459 const Elf32_Word *hashval; 4460 Elf32_Word bucket; 4461 Sym_Match_Result matchres; 4462 unsigned int h1, h2; 4463 unsigned long symnum; 4464 4465 matchres.sym_out = NULL; 4466 matchres.vsymp = NULL; 4467 matchres.vcount = 0; 4468 4469 /* Pick right bitmask word from Bloom filter array */ 4470 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4471 obj->maskwords_bm_gnu]; 4472 4473 /* Calculate modulus word size of gnu hash and its derivative */ 4474 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4475 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4476 4477 /* Filter out the "definitely not in set" queries */ 4478 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4479 return (ESRCH); 4480 4481 /* Locate hash chain and corresponding value element*/ 4482 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4483 if (bucket == 0) 4484 return (ESRCH); 4485 hashval = &obj->chain_zero_gnu[bucket]; 4486 do { 4487 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4488 symnum = hashval - obj->chain_zero_gnu; 4489 if (matched_symbol(req, obj, &matchres, symnum)) { 4490 req->sym_out = matchres.sym_out; 4491 req->defobj_out = obj; 4492 return (0); 4493 } 4494 } 4495 } while ((*hashval++ & 1) == 0); 4496 if (matchres.vcount == 1) { 4497 req->sym_out = matchres.vsymp; 4498 req->defobj_out = obj; 4499 return (0); 4500 } 4501 return (ESRCH); 4502 } 4503 4504 static void 4505 trace_loaded_objects(Obj_Entry *obj) 4506 { 4507 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4508 int c; 4509 4510 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4511 main_local = ""; 4512 4513 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4514 fmt1 = "\t%o => %p (%x)\n"; 4515 4516 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4517 fmt2 = "\t%o (%x)\n"; 4518 4519 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4520 4521 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4522 Needed_Entry *needed; 4523 const char *name, *path; 4524 bool is_lib; 4525 4526 if (obj->marker) 4527 continue; 4528 if (list_containers && obj->needed != NULL) 4529 rtld_printf("%s:\n", obj->path); 4530 for (needed = obj->needed; needed; needed = needed->next) { 4531 if (needed->obj != NULL) { 4532 if (needed->obj->traced && !list_containers) 4533 continue; 4534 needed->obj->traced = true; 4535 path = needed->obj->path; 4536 } else 4537 path = "not found"; 4538 4539 name = obj->strtab + needed->name; 4540 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4541 4542 fmt = is_lib ? fmt1 : fmt2; 4543 while ((c = *fmt++) != '\0') { 4544 switch (c) { 4545 default: 4546 rtld_putchar(c); 4547 continue; 4548 case '\\': 4549 switch (c = *fmt) { 4550 case '\0': 4551 continue; 4552 case 'n': 4553 rtld_putchar('\n'); 4554 break; 4555 case 't': 4556 rtld_putchar('\t'); 4557 break; 4558 } 4559 break; 4560 case '%': 4561 switch (c = *fmt) { 4562 case '\0': 4563 continue; 4564 case '%': 4565 default: 4566 rtld_putchar(c); 4567 break; 4568 case 'A': 4569 rtld_putstr(main_local); 4570 break; 4571 case 'a': 4572 rtld_putstr(obj_main->path); 4573 break; 4574 case 'o': 4575 rtld_putstr(name); 4576 break; 4577 #if 0 4578 case 'm': 4579 rtld_printf("%d", sodp->sod_major); 4580 break; 4581 case 'n': 4582 rtld_printf("%d", sodp->sod_minor); 4583 break; 4584 #endif 4585 case 'p': 4586 rtld_putstr(path); 4587 break; 4588 case 'x': 4589 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4590 0); 4591 break; 4592 } 4593 break; 4594 } 4595 ++fmt; 4596 } 4597 } 4598 } 4599 } 4600 4601 /* 4602 * Unload a dlopened object and its dependencies from memory and from 4603 * our data structures. It is assumed that the DAG rooted in the 4604 * object has already been unreferenced, and that the object has a 4605 * reference count of 0. 4606 */ 4607 static void 4608 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4609 { 4610 Obj_Entry marker, *obj, *next; 4611 4612 assert(root->refcount == 0); 4613 4614 /* 4615 * Pass over the DAG removing unreferenced objects from 4616 * appropriate lists. 4617 */ 4618 unlink_object(root); 4619 4620 /* Unmap all objects that are no longer referenced. */ 4621 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4622 next = TAILQ_NEXT(obj, next); 4623 if (obj->marker || obj->refcount != 0) 4624 continue; 4625 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4626 obj->mapsize, 0, obj->path); 4627 dbg("unloading \"%s\"", obj->path); 4628 /* 4629 * Unlink the object now to prevent new references from 4630 * being acquired while the bind lock is dropped in 4631 * recursive dlclose() invocations. 4632 */ 4633 TAILQ_REMOVE(&obj_list, obj, next); 4634 obj_count--; 4635 4636 if (obj->filtees_loaded) { 4637 if (next != NULL) { 4638 init_marker(&marker); 4639 TAILQ_INSERT_BEFORE(next, &marker, next); 4640 unload_filtees(obj, lockstate); 4641 next = TAILQ_NEXT(&marker, next); 4642 TAILQ_REMOVE(&obj_list, &marker, next); 4643 } else 4644 unload_filtees(obj, lockstate); 4645 } 4646 release_object(obj); 4647 } 4648 } 4649 4650 static void 4651 unlink_object(Obj_Entry *root) 4652 { 4653 Objlist_Entry *elm; 4654 4655 if (root->refcount == 0) { 4656 /* Remove the object from the RTLD_GLOBAL list. */ 4657 objlist_remove(&list_global, root); 4658 4659 /* Remove the object from all objects' DAG lists. */ 4660 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4661 objlist_remove(&elm->obj->dldags, root); 4662 if (elm->obj != root) 4663 unlink_object(elm->obj); 4664 } 4665 } 4666 } 4667 4668 static void 4669 ref_dag(Obj_Entry *root) 4670 { 4671 Objlist_Entry *elm; 4672 4673 assert(root->dag_inited); 4674 STAILQ_FOREACH(elm, &root->dagmembers, link) 4675 elm->obj->refcount++; 4676 } 4677 4678 static void 4679 unref_dag(Obj_Entry *root) 4680 { 4681 Objlist_Entry *elm; 4682 4683 assert(root->dag_inited); 4684 STAILQ_FOREACH(elm, &root->dagmembers, link) 4685 elm->obj->refcount--; 4686 } 4687 4688 /* 4689 * Common code for MD __tls_get_addr(). 4690 */ 4691 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4692 static void * 4693 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4694 { 4695 Elf_Addr *newdtv, *dtv; 4696 RtldLockState lockstate; 4697 int to_copy; 4698 4699 dtv = *dtvp; 4700 /* Check dtv generation in case new modules have arrived */ 4701 if (dtv[0] != tls_dtv_generation) { 4702 wlock_acquire(rtld_bind_lock, &lockstate); 4703 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4704 to_copy = dtv[1]; 4705 if (to_copy > tls_max_index) 4706 to_copy = tls_max_index; 4707 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4708 newdtv[0] = tls_dtv_generation; 4709 newdtv[1] = tls_max_index; 4710 free(dtv); 4711 lock_release(rtld_bind_lock, &lockstate); 4712 dtv = *dtvp = newdtv; 4713 } 4714 4715 /* Dynamically allocate module TLS if necessary */ 4716 if (dtv[index + 1] == 0) { 4717 /* Signal safe, wlock will block out signals. */ 4718 wlock_acquire(rtld_bind_lock, &lockstate); 4719 if (!dtv[index + 1]) 4720 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4721 lock_release(rtld_bind_lock, &lockstate); 4722 } 4723 return ((void *)(dtv[index + 1] + offset)); 4724 } 4725 4726 void * 4727 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4728 { 4729 Elf_Addr *dtv; 4730 4731 dtv = *dtvp; 4732 /* Check dtv generation in case new modules have arrived */ 4733 if (__predict_true(dtv[0] == tls_dtv_generation && 4734 dtv[index + 1] != 0)) 4735 return ((void *)(dtv[index + 1] + offset)); 4736 return (tls_get_addr_slow(dtvp, index, offset)); 4737 } 4738 4739 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4740 defined(__powerpc__) || defined(__riscv) 4741 4742 /* 4743 * Return pointer to allocated TLS block 4744 */ 4745 static void * 4746 get_tls_block_ptr(void *tcb, size_t tcbsize) 4747 { 4748 size_t extra_size, post_size, pre_size, tls_block_size; 4749 size_t tls_init_align; 4750 4751 tls_init_align = MAX(obj_main->tlsalign, 1); 4752 4753 /* Compute fragments sizes. */ 4754 extra_size = tcbsize - TLS_TCB_SIZE; 4755 post_size = calculate_tls_post_size(tls_init_align); 4756 tls_block_size = tcbsize + post_size; 4757 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4758 4759 return ((char *)tcb - pre_size - extra_size); 4760 } 4761 4762 /* 4763 * Allocate Static TLS using the Variant I method. 4764 * 4765 * For details on the layout, see lib/libc/gen/tls.c. 4766 * 4767 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4768 * it is based on tls_last_offset, and TLS offsets here are really TCB 4769 * offsets, whereas libc's tls_static_space is just the executable's static 4770 * TLS segment. 4771 */ 4772 void * 4773 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4774 { 4775 Obj_Entry *obj; 4776 char *tls_block; 4777 Elf_Addr *dtv, **tcb; 4778 Elf_Addr addr; 4779 Elf_Addr i; 4780 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4781 size_t tls_init_align; 4782 4783 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4784 return (oldtcb); 4785 4786 assert(tcbsize >= TLS_TCB_SIZE); 4787 maxalign = MAX(tcbalign, tls_static_max_align); 4788 tls_init_align = MAX(obj_main->tlsalign, 1); 4789 4790 /* Compute fragmets sizes. */ 4791 extra_size = tcbsize - TLS_TCB_SIZE; 4792 post_size = calculate_tls_post_size(tls_init_align); 4793 tls_block_size = tcbsize + post_size; 4794 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4795 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4796 4797 /* Allocate whole TLS block */ 4798 tls_block = malloc_aligned(tls_block_size, maxalign); 4799 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4800 4801 if (oldtcb != NULL) { 4802 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4803 tls_static_space); 4804 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4805 4806 /* Adjust the DTV. */ 4807 dtv = tcb[0]; 4808 for (i = 0; i < dtv[1]; i++) { 4809 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4810 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4811 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4812 } 4813 } 4814 } else { 4815 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4816 tcb[0] = dtv; 4817 dtv[0] = tls_dtv_generation; 4818 dtv[1] = tls_max_index; 4819 4820 for (obj = globallist_curr(objs); obj != NULL; 4821 obj = globallist_next(obj)) { 4822 if (obj->tlsoffset > 0) { 4823 addr = (Elf_Addr)tcb + obj->tlsoffset; 4824 if (obj->tlsinitsize > 0) 4825 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4826 if (obj->tlssize > obj->tlsinitsize) 4827 memset((void*)(addr + obj->tlsinitsize), 0, 4828 obj->tlssize - obj->tlsinitsize); 4829 dtv[obj->tlsindex + 1] = addr; 4830 } 4831 } 4832 } 4833 4834 return (tcb); 4835 } 4836 4837 void 4838 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4839 { 4840 Elf_Addr *dtv; 4841 Elf_Addr tlsstart, tlsend; 4842 size_t post_size; 4843 size_t dtvsize, i, tls_init_align; 4844 4845 assert(tcbsize >= TLS_TCB_SIZE); 4846 tls_init_align = MAX(obj_main->tlsalign, 1); 4847 4848 /* Compute fragments sizes. */ 4849 post_size = calculate_tls_post_size(tls_init_align); 4850 4851 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4852 tlsend = (Elf_Addr)tcb + tls_static_space; 4853 4854 dtv = *(Elf_Addr **)tcb; 4855 dtvsize = dtv[1]; 4856 for (i = 0; i < dtvsize; i++) { 4857 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4858 free((void*)dtv[i+2]); 4859 } 4860 } 4861 free(dtv); 4862 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4863 } 4864 4865 #endif 4866 4867 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4868 4869 /* 4870 * Allocate Static TLS using the Variant II method. 4871 */ 4872 void * 4873 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4874 { 4875 Obj_Entry *obj; 4876 size_t size, ralign; 4877 char *tls; 4878 Elf_Addr *dtv, *olddtv; 4879 Elf_Addr segbase, oldsegbase, addr; 4880 size_t i; 4881 4882 ralign = tcbalign; 4883 if (tls_static_max_align > ralign) 4884 ralign = tls_static_max_align; 4885 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4886 4887 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4888 tls = malloc_aligned(size, ralign); 4889 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4890 4891 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4892 ((Elf_Addr*)segbase)[0] = segbase; 4893 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4894 4895 dtv[0] = tls_dtv_generation; 4896 dtv[1] = tls_max_index; 4897 4898 if (oldtls) { 4899 /* 4900 * Copy the static TLS block over whole. 4901 */ 4902 oldsegbase = (Elf_Addr) oldtls; 4903 memcpy((void *)(segbase - tls_static_space), 4904 (const void *)(oldsegbase - tls_static_space), 4905 tls_static_space); 4906 4907 /* 4908 * If any dynamic TLS blocks have been created tls_get_addr(), 4909 * move them over. 4910 */ 4911 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4912 for (i = 0; i < olddtv[1]; i++) { 4913 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4914 dtv[i+2] = olddtv[i+2]; 4915 olddtv[i+2] = 0; 4916 } 4917 } 4918 4919 /* 4920 * We assume that this block was the one we created with 4921 * allocate_initial_tls(). 4922 */ 4923 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4924 } else { 4925 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4926 if (obj->marker || obj->tlsoffset == 0) 4927 continue; 4928 addr = segbase - obj->tlsoffset; 4929 memset((void*)(addr + obj->tlsinitsize), 4930 0, obj->tlssize - obj->tlsinitsize); 4931 if (obj->tlsinit) { 4932 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4933 obj->static_tls_copied = true; 4934 } 4935 dtv[obj->tlsindex + 1] = addr; 4936 } 4937 } 4938 4939 return (void*) segbase; 4940 } 4941 4942 void 4943 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4944 { 4945 Elf_Addr* dtv; 4946 size_t size, ralign; 4947 int dtvsize, i; 4948 Elf_Addr tlsstart, tlsend; 4949 4950 /* 4951 * Figure out the size of the initial TLS block so that we can 4952 * find stuff which ___tls_get_addr() allocated dynamically. 4953 */ 4954 ralign = tcbalign; 4955 if (tls_static_max_align > ralign) 4956 ralign = tls_static_max_align; 4957 size = round(tls_static_space, ralign); 4958 4959 dtv = ((Elf_Addr**)tls)[1]; 4960 dtvsize = dtv[1]; 4961 tlsend = (Elf_Addr) tls; 4962 tlsstart = tlsend - size; 4963 for (i = 0; i < dtvsize; i++) { 4964 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4965 free_aligned((void *)dtv[i + 2]); 4966 } 4967 } 4968 4969 free_aligned((void *)tlsstart); 4970 free((void*) dtv); 4971 } 4972 4973 #endif 4974 4975 /* 4976 * Allocate TLS block for module with given index. 4977 */ 4978 void * 4979 allocate_module_tls(int index) 4980 { 4981 Obj_Entry* obj; 4982 char* p; 4983 4984 TAILQ_FOREACH(obj, &obj_list, next) { 4985 if (obj->marker) 4986 continue; 4987 if (obj->tlsindex == index) 4988 break; 4989 } 4990 if (!obj) { 4991 _rtld_error("Can't find module with TLS index %d", index); 4992 rtld_die(); 4993 } 4994 4995 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4996 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4997 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4998 4999 return p; 5000 } 5001 5002 bool 5003 allocate_tls_offset(Obj_Entry *obj) 5004 { 5005 size_t off; 5006 5007 if (obj->tls_done) 5008 return true; 5009 5010 if (obj->tlssize == 0) { 5011 obj->tls_done = true; 5012 return true; 5013 } 5014 5015 if (tls_last_offset == 0) 5016 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5017 else 5018 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5019 obj->tlssize, obj->tlsalign); 5020 5021 /* 5022 * If we have already fixed the size of the static TLS block, we 5023 * must stay within that size. When allocating the static TLS, we 5024 * leave a small amount of space spare to be used for dynamically 5025 * loading modules which use static TLS. 5026 */ 5027 if (tls_static_space != 0) { 5028 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5029 return false; 5030 } else if (obj->tlsalign > tls_static_max_align) { 5031 tls_static_max_align = obj->tlsalign; 5032 } 5033 5034 tls_last_offset = obj->tlsoffset = off; 5035 tls_last_size = obj->tlssize; 5036 obj->tls_done = true; 5037 5038 return true; 5039 } 5040 5041 void 5042 free_tls_offset(Obj_Entry *obj) 5043 { 5044 5045 /* 5046 * If we were the last thing to allocate out of the static TLS 5047 * block, we give our space back to the 'allocator'. This is a 5048 * simplistic workaround to allow libGL.so.1 to be loaded and 5049 * unloaded multiple times. 5050 */ 5051 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5052 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5053 tls_last_offset -= obj->tlssize; 5054 tls_last_size = 0; 5055 } 5056 } 5057 5058 void * 5059 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5060 { 5061 void *ret; 5062 RtldLockState lockstate; 5063 5064 wlock_acquire(rtld_bind_lock, &lockstate); 5065 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5066 tcbsize, tcbalign); 5067 lock_release(rtld_bind_lock, &lockstate); 5068 return (ret); 5069 } 5070 5071 void 5072 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5073 { 5074 RtldLockState lockstate; 5075 5076 wlock_acquire(rtld_bind_lock, &lockstate); 5077 free_tls(tcb, tcbsize, tcbalign); 5078 lock_release(rtld_bind_lock, &lockstate); 5079 } 5080 5081 static void 5082 object_add_name(Obj_Entry *obj, const char *name) 5083 { 5084 Name_Entry *entry; 5085 size_t len; 5086 5087 len = strlen(name); 5088 entry = malloc(sizeof(Name_Entry) + len); 5089 5090 if (entry != NULL) { 5091 strcpy(entry->name, name); 5092 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5093 } 5094 } 5095 5096 static int 5097 object_match_name(const Obj_Entry *obj, const char *name) 5098 { 5099 Name_Entry *entry; 5100 5101 STAILQ_FOREACH(entry, &obj->names, link) { 5102 if (strcmp(name, entry->name) == 0) 5103 return (1); 5104 } 5105 return (0); 5106 } 5107 5108 static Obj_Entry * 5109 locate_dependency(const Obj_Entry *obj, const char *name) 5110 { 5111 const Objlist_Entry *entry; 5112 const Needed_Entry *needed; 5113 5114 STAILQ_FOREACH(entry, &list_main, link) { 5115 if (object_match_name(entry->obj, name)) 5116 return entry->obj; 5117 } 5118 5119 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5120 if (strcmp(obj->strtab + needed->name, name) == 0 || 5121 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5122 /* 5123 * If there is DT_NEEDED for the name we are looking for, 5124 * we are all set. Note that object might not be found if 5125 * dependency was not loaded yet, so the function can 5126 * return NULL here. This is expected and handled 5127 * properly by the caller. 5128 */ 5129 return (needed->obj); 5130 } 5131 } 5132 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5133 obj->path, name); 5134 rtld_die(); 5135 } 5136 5137 static int 5138 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5139 const Elf_Vernaux *vna) 5140 { 5141 const Elf_Verdef *vd; 5142 const char *vername; 5143 5144 vername = refobj->strtab + vna->vna_name; 5145 vd = depobj->verdef; 5146 if (vd == NULL) { 5147 _rtld_error("%s: version %s required by %s not defined", 5148 depobj->path, vername, refobj->path); 5149 return (-1); 5150 } 5151 for (;;) { 5152 if (vd->vd_version != VER_DEF_CURRENT) { 5153 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5154 depobj->path, vd->vd_version); 5155 return (-1); 5156 } 5157 if (vna->vna_hash == vd->vd_hash) { 5158 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5159 ((const char *)vd + vd->vd_aux); 5160 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5161 return (0); 5162 } 5163 if (vd->vd_next == 0) 5164 break; 5165 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5166 } 5167 if (vna->vna_flags & VER_FLG_WEAK) 5168 return (0); 5169 _rtld_error("%s: version %s required by %s not found", 5170 depobj->path, vername, refobj->path); 5171 return (-1); 5172 } 5173 5174 static int 5175 rtld_verify_object_versions(Obj_Entry *obj) 5176 { 5177 const Elf_Verneed *vn; 5178 const Elf_Verdef *vd; 5179 const Elf_Verdaux *vda; 5180 const Elf_Vernaux *vna; 5181 const Obj_Entry *depobj; 5182 int maxvernum, vernum; 5183 5184 if (obj->ver_checked) 5185 return (0); 5186 obj->ver_checked = true; 5187 5188 maxvernum = 0; 5189 /* 5190 * Walk over defined and required version records and figure out 5191 * max index used by any of them. Do very basic sanity checking 5192 * while there. 5193 */ 5194 vn = obj->verneed; 5195 while (vn != NULL) { 5196 if (vn->vn_version != VER_NEED_CURRENT) { 5197 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5198 obj->path, vn->vn_version); 5199 return (-1); 5200 } 5201 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5202 for (;;) { 5203 vernum = VER_NEED_IDX(vna->vna_other); 5204 if (vernum > maxvernum) 5205 maxvernum = vernum; 5206 if (vna->vna_next == 0) 5207 break; 5208 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5209 } 5210 if (vn->vn_next == 0) 5211 break; 5212 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5213 } 5214 5215 vd = obj->verdef; 5216 while (vd != NULL) { 5217 if (vd->vd_version != VER_DEF_CURRENT) { 5218 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5219 obj->path, vd->vd_version); 5220 return (-1); 5221 } 5222 vernum = VER_DEF_IDX(vd->vd_ndx); 5223 if (vernum > maxvernum) 5224 maxvernum = vernum; 5225 if (vd->vd_next == 0) 5226 break; 5227 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5228 } 5229 5230 if (maxvernum == 0) 5231 return (0); 5232 5233 /* 5234 * Store version information in array indexable by version index. 5235 * Verify that object version requirements are satisfied along the 5236 * way. 5237 */ 5238 obj->vernum = maxvernum + 1; 5239 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5240 5241 vd = obj->verdef; 5242 while (vd != NULL) { 5243 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5244 vernum = VER_DEF_IDX(vd->vd_ndx); 5245 assert(vernum <= maxvernum); 5246 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5247 obj->vertab[vernum].hash = vd->vd_hash; 5248 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5249 obj->vertab[vernum].file = NULL; 5250 obj->vertab[vernum].flags = 0; 5251 } 5252 if (vd->vd_next == 0) 5253 break; 5254 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5255 } 5256 5257 vn = obj->verneed; 5258 while (vn != NULL) { 5259 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5260 if (depobj == NULL) 5261 return (-1); 5262 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5263 for (;;) { 5264 if (check_object_provided_version(obj, depobj, vna)) 5265 return (-1); 5266 vernum = VER_NEED_IDX(vna->vna_other); 5267 assert(vernum <= maxvernum); 5268 obj->vertab[vernum].hash = vna->vna_hash; 5269 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5270 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5271 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5272 VER_INFO_HIDDEN : 0; 5273 if (vna->vna_next == 0) 5274 break; 5275 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5276 } 5277 if (vn->vn_next == 0) 5278 break; 5279 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5280 } 5281 return 0; 5282 } 5283 5284 static int 5285 rtld_verify_versions(const Objlist *objlist) 5286 { 5287 Objlist_Entry *entry; 5288 int rc; 5289 5290 rc = 0; 5291 STAILQ_FOREACH(entry, objlist, link) { 5292 /* 5293 * Skip dummy objects or objects that have their version requirements 5294 * already checked. 5295 */ 5296 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5297 continue; 5298 if (rtld_verify_object_versions(entry->obj) == -1) { 5299 rc = -1; 5300 if (ld_tracing == NULL) 5301 break; 5302 } 5303 } 5304 if (rc == 0 || ld_tracing != NULL) 5305 rc = rtld_verify_object_versions(&obj_rtld); 5306 return rc; 5307 } 5308 5309 const Ver_Entry * 5310 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5311 { 5312 Elf_Versym vernum; 5313 5314 if (obj->vertab) { 5315 vernum = VER_NDX(obj->versyms[symnum]); 5316 if (vernum >= obj->vernum) { 5317 _rtld_error("%s: symbol %s has wrong verneed value %d", 5318 obj->path, obj->strtab + symnum, vernum); 5319 } else if (obj->vertab[vernum].hash != 0) { 5320 return &obj->vertab[vernum]; 5321 } 5322 } 5323 return NULL; 5324 } 5325 5326 int 5327 _rtld_get_stack_prot(void) 5328 { 5329 5330 return (stack_prot); 5331 } 5332 5333 int 5334 _rtld_is_dlopened(void *arg) 5335 { 5336 Obj_Entry *obj; 5337 RtldLockState lockstate; 5338 int res; 5339 5340 rlock_acquire(rtld_bind_lock, &lockstate); 5341 obj = dlcheck(arg); 5342 if (obj == NULL) 5343 obj = obj_from_addr(arg); 5344 if (obj == NULL) { 5345 _rtld_error("No shared object contains address"); 5346 lock_release(rtld_bind_lock, &lockstate); 5347 return (-1); 5348 } 5349 res = obj->dlopened ? 1 : 0; 5350 lock_release(rtld_bind_lock, &lockstate); 5351 return (res); 5352 } 5353 5354 static int 5355 obj_remap_relro(Obj_Entry *obj, int prot) 5356 { 5357 5358 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5359 prot) == -1) { 5360 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5361 obj->path, prot, rtld_strerror(errno)); 5362 return (-1); 5363 } 5364 return (0); 5365 } 5366 5367 static int 5368 obj_disable_relro(Obj_Entry *obj) 5369 { 5370 5371 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5372 } 5373 5374 static int 5375 obj_enforce_relro(Obj_Entry *obj) 5376 { 5377 5378 return (obj_remap_relro(obj, PROT_READ)); 5379 } 5380 5381 static void 5382 map_stacks_exec(RtldLockState *lockstate) 5383 { 5384 void (*thr_map_stacks_exec)(void); 5385 5386 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5387 return; 5388 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5389 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5390 if (thr_map_stacks_exec != NULL) { 5391 stack_prot |= PROT_EXEC; 5392 thr_map_stacks_exec(); 5393 } 5394 } 5395 5396 static void 5397 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5398 { 5399 Objlist_Entry *elm; 5400 Obj_Entry *obj; 5401 void (*distrib)(size_t, void *, size_t, size_t); 5402 5403 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5404 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5405 if (distrib == NULL) 5406 return; 5407 STAILQ_FOREACH(elm, list, link) { 5408 obj = elm->obj; 5409 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5410 continue; 5411 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5412 obj->tlssize); 5413 obj->static_tls_copied = true; 5414 } 5415 } 5416 5417 void 5418 symlook_init(SymLook *dst, const char *name) 5419 { 5420 5421 bzero(dst, sizeof(*dst)); 5422 dst->name = name; 5423 dst->hash = elf_hash(name); 5424 dst->hash_gnu = gnu_hash(name); 5425 } 5426 5427 static void 5428 symlook_init_from_req(SymLook *dst, const SymLook *src) 5429 { 5430 5431 dst->name = src->name; 5432 dst->hash = src->hash; 5433 dst->hash_gnu = src->hash_gnu; 5434 dst->ventry = src->ventry; 5435 dst->flags = src->flags; 5436 dst->defobj_out = NULL; 5437 dst->sym_out = NULL; 5438 dst->lockstate = src->lockstate; 5439 } 5440 5441 static int 5442 open_binary_fd(const char *argv0, bool search_in_path) 5443 { 5444 char *pathenv, *pe, binpath[PATH_MAX]; 5445 int fd; 5446 5447 if (search_in_path && strchr(argv0, '/') == NULL) { 5448 pathenv = getenv("PATH"); 5449 if (pathenv == NULL) { 5450 _rtld_error("-p and no PATH environment variable"); 5451 rtld_die(); 5452 } 5453 pathenv = strdup(pathenv); 5454 if (pathenv == NULL) { 5455 _rtld_error("Cannot allocate memory"); 5456 rtld_die(); 5457 } 5458 fd = -1; 5459 errno = ENOENT; 5460 while ((pe = strsep(&pathenv, ":")) != NULL) { 5461 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5462 sizeof(binpath)) 5463 continue; 5464 if (binpath[0] != '\0' && 5465 strlcat(binpath, "/", sizeof(binpath)) >= 5466 sizeof(binpath)) 5467 continue; 5468 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5469 sizeof(binpath)) 5470 continue; 5471 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5472 if (fd != -1 || errno != ENOENT) 5473 break; 5474 } 5475 free(pathenv); 5476 } else { 5477 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5478 } 5479 5480 if (fd == -1) { 5481 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5482 rtld_die(); 5483 } 5484 return (fd); 5485 } 5486 5487 /* 5488 * Parse a set of command-line arguments. 5489 */ 5490 static int 5491 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5492 { 5493 const char *arg; 5494 int fd, i, j, arglen; 5495 char opt; 5496 5497 dbg("Parsing command-line arguments"); 5498 *use_pathp = false; 5499 *fdp = -1; 5500 5501 for (i = 1; i < argc; i++ ) { 5502 arg = argv[i]; 5503 dbg("argv[%d]: '%s'", i, arg); 5504 5505 /* 5506 * rtld arguments end with an explicit "--" or with the first 5507 * non-prefixed argument. 5508 */ 5509 if (strcmp(arg, "--") == 0) { 5510 i++; 5511 break; 5512 } 5513 if (arg[0] != '-') 5514 break; 5515 5516 /* 5517 * All other arguments are single-character options that can 5518 * be combined, so we need to search through `arg` for them. 5519 */ 5520 arglen = strlen(arg); 5521 for (j = 1; j < arglen; j++) { 5522 opt = arg[j]; 5523 if (opt == 'h') { 5524 print_usage(argv[0]); 5525 _exit(0); 5526 } else if (opt == 'f') { 5527 /* 5528 * -f XX can be used to specify a descriptor for the 5529 * binary named at the command line (i.e., the later 5530 * argument will specify the process name but the 5531 * descriptor is what will actually be executed) 5532 */ 5533 if (j != arglen - 1) { 5534 /* -f must be the last option in, e.g., -abcf */ 5535 _rtld_error("Invalid options: %s", arg); 5536 rtld_die(); 5537 } 5538 i++; 5539 fd = parse_integer(argv[i]); 5540 if (fd == -1) { 5541 _rtld_error("Invalid file descriptor: '%s'", 5542 argv[i]); 5543 rtld_die(); 5544 } 5545 *fdp = fd; 5546 break; 5547 } else if (opt == 'p') { 5548 *use_pathp = true; 5549 } else { 5550 _rtld_error("Invalid argument: '%s'", arg); 5551 print_usage(argv[0]); 5552 rtld_die(); 5553 } 5554 } 5555 } 5556 5557 return (i); 5558 } 5559 5560 /* 5561 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5562 */ 5563 static int 5564 parse_integer(const char *str) 5565 { 5566 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5567 const char *orig; 5568 int n; 5569 char c; 5570 5571 orig = str; 5572 n = 0; 5573 for (c = *str; c != '\0'; c = *++str) { 5574 if (c < '0' || c > '9') 5575 return (-1); 5576 5577 n *= RADIX; 5578 n += c - '0'; 5579 } 5580 5581 /* Make sure we actually parsed something. */ 5582 if (str == orig) 5583 return (-1); 5584 return (n); 5585 } 5586 5587 static void 5588 print_usage(const char *argv0) 5589 { 5590 5591 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5592 "\n" 5593 "Options:\n" 5594 " -h Display this help message\n" 5595 " -p Search in PATH for named binary\n" 5596 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5597 " -- End of RTLD options\n" 5598 " <binary> Name of process to execute\n" 5599 " <args> Arguments to the executed process\n", argv0); 5600 } 5601 5602 /* 5603 * Overrides for libc_pic-provided functions. 5604 */ 5605 5606 int 5607 __getosreldate(void) 5608 { 5609 size_t len; 5610 int oid[2]; 5611 int error, osrel; 5612 5613 if (osreldate != 0) 5614 return (osreldate); 5615 5616 oid[0] = CTL_KERN; 5617 oid[1] = KERN_OSRELDATE; 5618 osrel = 0; 5619 len = sizeof(osrel); 5620 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5621 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5622 osreldate = osrel; 5623 return (osreldate); 5624 } 5625 5626 void 5627 exit(int status) 5628 { 5629 5630 _exit(status); 5631 } 5632 5633 void (*__cleanup)(void); 5634 int __isthreaded = 0; 5635 int _thread_autoinit_dummy_decl = 1; 5636 5637 /* 5638 * No unresolved symbols for rtld. 5639 */ 5640 void 5641 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5642 { 5643 } 5644 5645 const char * 5646 rtld_strerror(int errnum) 5647 { 5648 5649 if (errnum < 0 || errnum >= sys_nerr) 5650 return ("Unknown error"); 5651 return (sys_errlist[errnum]); 5652 } 5653 5654 /* 5655 * No ifunc relocations. 5656 */ 5657 void * 5658 memset(void *dest, int c, size_t len) 5659 { 5660 size_t i; 5661 5662 for (i = 0; i < len; i++) 5663 ((char *)dest)[i] = c; 5664 return (dest); 5665 } 5666 5667 void 5668 bzero(void *dest, size_t len) 5669 { 5670 size_t i; 5671 5672 for (i = 0; i < len; i++) 5673 ((char *)dest)[i] = 0; 5674 } 5675 5676 /* malloc */ 5677 void * 5678 malloc(size_t nbytes) 5679 { 5680 5681 return (__crt_malloc(nbytes)); 5682 } 5683 5684 void * 5685 calloc(size_t num, size_t size) 5686 { 5687 5688 return (__crt_calloc(num, size)); 5689 } 5690 5691 void 5692 free(void *cp) 5693 { 5694 5695 __crt_free(cp); 5696 } 5697 5698 void * 5699 realloc(void *cp, size_t nbytes) 5700 { 5701 5702 return (__crt_realloc(cp, nbytes)); 5703 } 5704