1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <[email protected]>. 6 * Copyright 2009-2013 Konstantin Belousov <[email protected]>. 7 * Copyright 2012 John Marino <[email protected]>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <[email protected]>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_utrace.h" 70 #include "notes.h" 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 81 const Elf_Dyn **, const Elf_Dyn **); 82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 83 const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static int dlclose_locked(void *, RtldLockState *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *, int *); 97 static const char *gethints(bool); 98 static void hold_object(Obj_Entry *); 99 static void unhold_object(Obj_Entry *); 100 static void init_dag(Obj_Entry *); 101 static void init_marker(Obj_Entry *); 102 static void init_pagesizes(Elf_Auxinfo **aux_info); 103 static void init_rtld(caddr_t, Elf_Auxinfo **); 104 static void initlist_add_neededs(Needed_Entry *, Objlist *); 105 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 106 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 107 static void linkmap_add(Obj_Entry *); 108 static void linkmap_delete(Obj_Entry *); 109 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 110 static void unload_filtees(Obj_Entry *, RtldLockState *); 111 static int load_needed_objects(Obj_Entry *, int); 112 static int load_preload_objects(void); 113 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 114 static void map_stacks_exec(RtldLockState *); 115 static int obj_disable_relro(Obj_Entry *); 116 static int obj_enforce_relro(Obj_Entry *); 117 static Obj_Entry *obj_from_addr(const void *); 118 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 119 static void objlist_call_init(Objlist *, RtldLockState *); 120 static void objlist_clear(Objlist *); 121 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 122 static void objlist_init(Objlist *); 123 static void objlist_push_head(Objlist *, Obj_Entry *); 124 static void objlist_push_tail(Objlist *, Obj_Entry *); 125 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 126 static void objlist_remove(Objlist *, Obj_Entry *); 127 static int open_binary_fd(const char *argv0, bool search_in_path); 128 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 129 static int parse_integer(const char *); 130 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 131 static void print_usage(const char *argv0); 132 static void release_object(Obj_Entry *); 133 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 134 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 135 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 136 int flags, RtldLockState *lockstate); 137 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 138 RtldLockState *); 139 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 140 static int rtld_dirname(const char *, char *); 141 static int rtld_dirname_abs(const char *, char *); 142 static void *rtld_dlopen(const char *name, int fd, int mode); 143 static void rtld_exit(void); 144 static char *search_library_path(const char *, const char *, const char *, 145 int *); 146 static char *search_library_pathfds(const char *, const char *, int *); 147 static const void **get_program_var_addr(const char *, RtldLockState *); 148 static void set_program_var(const char *, const void *); 149 static int symlook_default(SymLook *, const Obj_Entry *refobj); 150 static int symlook_global(SymLook *, DoneList *); 151 static void symlook_init_from_req(SymLook *, const SymLook *); 152 static int symlook_list(SymLook *, const Objlist *, DoneList *); 153 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 154 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 155 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 156 static void trace_loaded_objects(Obj_Entry *); 157 static void unlink_object(Obj_Entry *); 158 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 159 static void unref_dag(Obj_Entry *); 160 static void ref_dag(Obj_Entry *); 161 static char *origin_subst_one(Obj_Entry *, char *, const char *, 162 const char *, bool); 163 static char *origin_subst(Obj_Entry *, char *); 164 static bool obj_resolve_origin(Obj_Entry *obj); 165 static void preinit_main(void); 166 static int rtld_verify_versions(const Objlist *); 167 static int rtld_verify_object_versions(Obj_Entry *); 168 static void object_add_name(Obj_Entry *, const char *); 169 static int object_match_name(const Obj_Entry *, const char *); 170 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 171 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 172 struct dl_phdr_info *phdr_info); 173 static uint32_t gnu_hash(const char *); 174 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 175 const unsigned long); 176 177 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 178 void _r_debug_postinit(struct link_map *) __noinline __exported; 179 180 int __sys_openat(int, const char *, int, ...); 181 182 /* 183 * Data declarations. 184 */ 185 static char *error_message; /* Message for dlerror(), or NULL */ 186 struct r_debug r_debug __exported; /* for GDB; */ 187 static bool libmap_disable; /* Disable libmap */ 188 static bool ld_loadfltr; /* Immediate filters processing */ 189 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 190 static bool trust; /* False for setuid and setgid programs */ 191 static bool dangerous_ld_env; /* True if environment variables have been 192 used to affect the libraries loaded */ 193 bool ld_bind_not; /* Disable PLT update */ 194 static char *ld_bind_now; /* Environment variable for immediate binding */ 195 static char *ld_debug; /* Environment variable for debugging */ 196 static char *ld_library_path; /* Environment variable for search path */ 197 static char *ld_library_dirs; /* Environment variable for library descriptors */ 198 static char *ld_preload; /* Environment variable for libraries to 199 load first */ 200 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 201 static char *ld_tracing; /* Called from ldd to print libs */ 202 static char *ld_utrace; /* Use utrace() to log events. */ 203 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 204 static Obj_Entry *obj_main; /* The main program shared object */ 205 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 206 static unsigned int obj_count; /* Number of objects in obj_list */ 207 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 208 209 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 210 STAILQ_HEAD_INITIALIZER(list_global); 211 static Objlist list_main = /* Objects loaded at program startup */ 212 STAILQ_HEAD_INITIALIZER(list_main); 213 static Objlist list_fini = /* Objects needing fini() calls */ 214 STAILQ_HEAD_INITIALIZER(list_fini); 215 216 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 217 218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 219 220 extern Elf_Dyn _DYNAMIC; 221 #pragma weak _DYNAMIC 222 223 int dlclose(void *) __exported; 224 char *dlerror(void) __exported; 225 void *dlopen(const char *, int) __exported; 226 void *fdlopen(int, int) __exported; 227 void *dlsym(void *, const char *) __exported; 228 dlfunc_t dlfunc(void *, const char *) __exported; 229 void *dlvsym(void *, const char *, const char *) __exported; 230 int dladdr(const void *, Dl_info *) __exported; 231 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 232 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 233 int dlinfo(void *, int , void *) __exported; 234 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 235 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 236 int _rtld_get_stack_prot(void) __exported; 237 int _rtld_is_dlopened(void *) __exported; 238 void _rtld_error(const char *, ...) __exported; 239 240 int npagesizes, osreldate; 241 size_t *pagesizes; 242 243 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 244 static int max_stack_flags; 245 246 /* 247 * Global declarations normally provided by crt1. The dynamic linker is 248 * not built with crt1, so we have to provide them ourselves. 249 */ 250 char *__progname; 251 char **environ; 252 253 /* 254 * Used to pass argc, argv to init functions. 255 */ 256 int main_argc; 257 char **main_argv; 258 259 /* 260 * Globals to control TLS allocation. 261 */ 262 size_t tls_last_offset; /* Static TLS offset of last module */ 263 size_t tls_last_size; /* Static TLS size of last module */ 264 size_t tls_static_space; /* Static TLS space allocated */ 265 size_t tls_static_max_align; 266 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 267 int tls_max_index = 1; /* Largest module index allocated */ 268 269 bool ld_library_path_rpath = false; 270 271 /* 272 * Globals for path names, and such 273 */ 274 char *ld_elf_hints_default = _PATH_ELF_HINTS; 275 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 276 char *ld_path_rtld = _PATH_RTLD; 277 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 278 char *ld_env_prefix = LD_; 279 280 /* 281 * Fill in a DoneList with an allocation large enough to hold all of 282 * the currently-loaded objects. Keep this as a macro since it calls 283 * alloca and we want that to occur within the scope of the caller. 284 */ 285 #define donelist_init(dlp) \ 286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 287 assert((dlp)->objs != NULL), \ 288 (dlp)->num_alloc = obj_count, \ 289 (dlp)->num_used = 0) 290 291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294 } while (0) 295 296 static void 297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299 { 300 struct utrace_rtld ut; 301 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 302 303 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 #ifdef RTLD_VARIANT_ENV_NAMES 316 /* 317 * construct the env variable based on the type of binary that's 318 * running. 319 */ 320 static inline const char * 321 _LD(const char *var) 322 { 323 static char buffer[128]; 324 325 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 326 strlcat(buffer, var, sizeof(buffer)); 327 return (buffer); 328 } 329 #else 330 #define _LD(x) LD_ x 331 #endif 332 333 /* 334 * Main entry point for dynamic linking. The first argument is the 335 * stack pointer. The stack is expected to be laid out as described 336 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 337 * Specifically, the stack pointer points to a word containing 338 * ARGC. Following that in the stack is a null-terminated sequence 339 * of pointers to argument strings. Then comes a null-terminated 340 * sequence of pointers to environment strings. Finally, there is a 341 * sequence of "auxiliary vector" entries. 342 * 343 * The second argument points to a place to store the dynamic linker's 344 * exit procedure pointer and the third to a place to store the main 345 * program's object. 346 * 347 * The return value is the main program's entry point. 348 */ 349 func_ptr_type 350 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 351 { 352 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 353 Objlist_Entry *entry; 354 Obj_Entry *last_interposer, *obj, *preload_tail; 355 const Elf_Phdr *phdr; 356 Objlist initlist; 357 RtldLockState lockstate; 358 struct stat st; 359 Elf_Addr *argcp; 360 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 361 caddr_t imgentry; 362 char buf[MAXPATHLEN]; 363 int argc, fd, i, phnum, rtld_argc; 364 bool dir_enable, explicit_fd, search_in_path; 365 366 /* 367 * On entry, the dynamic linker itself has not been relocated yet. 368 * Be very careful not to reference any global data until after 369 * init_rtld has returned. It is OK to reference file-scope statics 370 * and string constants, and to call static and global functions. 371 */ 372 373 /* Find the auxiliary vector on the stack. */ 374 argcp = sp; 375 argc = *sp++; 376 argv = (char **) sp; 377 sp += argc + 1; /* Skip over arguments and NULL terminator */ 378 env = (char **) sp; 379 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 380 ; 381 aux = (Elf_Auxinfo *) sp; 382 383 /* Digest the auxiliary vector. */ 384 for (i = 0; i < AT_COUNT; i++) 385 aux_info[i] = NULL; 386 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 387 if (auxp->a_type < AT_COUNT) 388 aux_info[auxp->a_type] = auxp; 389 } 390 391 /* Initialize and relocate ourselves. */ 392 assert(aux_info[AT_BASE] != NULL); 393 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 394 395 __progname = obj_rtld.path; 396 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 397 environ = env; 398 main_argc = argc; 399 main_argv = argv; 400 401 trust = !issetugid(); 402 403 md_abi_variant_hook(aux_info); 404 405 fd = -1; 406 if (aux_info[AT_EXECFD] != NULL) { 407 fd = aux_info[AT_EXECFD]->a_un.a_val; 408 } else { 409 assert(aux_info[AT_PHDR] != NULL); 410 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 411 if (phdr == obj_rtld.phdr) { 412 if (!trust) { 413 _rtld_error("Tainted process refusing to run binary %s", 414 argv0); 415 rtld_die(); 416 } 417 dbg("opening main program in direct exec mode"); 418 if (argc >= 2) { 419 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 420 argv0 = argv[rtld_argc]; 421 explicit_fd = (fd != -1); 422 if (!explicit_fd) 423 fd = open_binary_fd(argv0, search_in_path); 424 if (fstat(fd, &st) == -1) { 425 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 426 explicit_fd ? "user-provided descriptor" : argv0, 427 rtld_strerror(errno)); 428 rtld_die(); 429 } 430 431 /* 432 * Rough emulation of the permission checks done by 433 * execve(2), only Unix DACs are checked, ACLs are 434 * ignored. Preserve the semantic of disabling owner 435 * to execute if owner x bit is cleared, even if 436 * others x bit is enabled. 437 * mmap(2) does not allow to mmap with PROT_EXEC if 438 * binary' file comes from noexec mount. We cannot 439 * set VV_TEXT on the binary. 440 */ 441 dir_enable = false; 442 if (st.st_uid == geteuid()) { 443 if ((st.st_mode & S_IXUSR) != 0) 444 dir_enable = true; 445 } else if (st.st_gid == getegid()) { 446 if ((st.st_mode & S_IXGRP) != 0) 447 dir_enable = true; 448 } else if ((st.st_mode & S_IXOTH) != 0) { 449 dir_enable = true; 450 } 451 if (!dir_enable) { 452 _rtld_error("No execute permission for binary %s", 453 argv0); 454 rtld_die(); 455 } 456 457 /* 458 * For direct exec mode, argv[0] is the interpreter 459 * name, we must remove it and shift arguments left 460 * before invoking binary main. Since stack layout 461 * places environment pointers and aux vectors right 462 * after the terminating NULL, we must shift 463 * environment and aux as well. 464 */ 465 main_argc = argc - rtld_argc; 466 for (i = 0; i <= main_argc; i++) 467 argv[i] = argv[i + rtld_argc]; 468 *argcp -= rtld_argc; 469 environ = env = envp = argv + main_argc + 1; 470 do { 471 *envp = *(envp + rtld_argc); 472 envp++; 473 } while (*envp != NULL); 474 aux = auxp = (Elf_Auxinfo *)envp; 475 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 476 for (;; auxp++, auxpf++) { 477 *auxp = *auxpf; 478 if (auxp->a_type == AT_NULL) 479 break; 480 } 481 } else { 482 _rtld_error("No binary"); 483 rtld_die(); 484 } 485 } 486 } 487 488 ld_bind_now = getenv(_LD("BIND_NOW")); 489 490 /* 491 * If the process is tainted, then we un-set the dangerous environment 492 * variables. The process will be marked as tainted until setuid(2) 493 * is called. If any child process calls setuid(2) we do not want any 494 * future processes to honor the potentially un-safe variables. 495 */ 496 if (!trust) { 497 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 498 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 499 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 500 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 501 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 502 _rtld_error("environment corrupt; aborting"); 503 rtld_die(); 504 } 505 } 506 ld_debug = getenv(_LD("DEBUG")); 507 if (ld_bind_now == NULL) 508 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 509 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 510 libmap_override = getenv(_LD("LIBMAP")); 511 ld_library_path = getenv(_LD("LIBRARY_PATH")); 512 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 513 ld_preload = getenv(_LD("PRELOAD")); 514 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 515 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 516 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 517 if (library_path_rpath != NULL) { 518 if (library_path_rpath[0] == 'y' || 519 library_path_rpath[0] == 'Y' || 520 library_path_rpath[0] == '1') 521 ld_library_path_rpath = true; 522 else 523 ld_library_path_rpath = false; 524 } 525 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 526 (ld_library_path != NULL) || (ld_preload != NULL) || 527 (ld_elf_hints_path != NULL) || ld_loadfltr; 528 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 529 ld_utrace = getenv(_LD("UTRACE")); 530 531 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 532 ld_elf_hints_path = ld_elf_hints_default; 533 534 if (ld_debug != NULL && *ld_debug != '\0') 535 debug = 1; 536 dbg("%s is initialized, base address = %p", __progname, 537 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 538 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 539 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 540 541 dbg("initializing thread locks"); 542 lockdflt_init(); 543 544 /* 545 * Load the main program, or process its program header if it is 546 * already loaded. 547 */ 548 if (fd != -1) { /* Load the main program. */ 549 dbg("loading main program"); 550 obj_main = map_object(fd, argv0, NULL); 551 close(fd); 552 if (obj_main == NULL) 553 rtld_die(); 554 max_stack_flags = obj_main->stack_flags; 555 } else { /* Main program already loaded. */ 556 dbg("processing main program's program header"); 557 assert(aux_info[AT_PHDR] != NULL); 558 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 559 assert(aux_info[AT_PHNUM] != NULL); 560 phnum = aux_info[AT_PHNUM]->a_un.a_val; 561 assert(aux_info[AT_PHENT] != NULL); 562 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 563 assert(aux_info[AT_ENTRY] != NULL); 564 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 565 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 566 rtld_die(); 567 } 568 569 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 570 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 571 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 572 if (kexecpath[0] == '/') 573 obj_main->path = kexecpath; 574 else if (getcwd(buf, sizeof(buf)) == NULL || 575 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 576 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 577 obj_main->path = xstrdup(argv0); 578 else 579 obj_main->path = xstrdup(buf); 580 } else { 581 dbg("No AT_EXECPATH or direct exec"); 582 obj_main->path = xstrdup(argv0); 583 } 584 dbg("obj_main path %s", obj_main->path); 585 obj_main->mainprog = true; 586 587 if (aux_info[AT_STACKPROT] != NULL && 588 aux_info[AT_STACKPROT]->a_un.a_val != 0) 589 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 590 591 #ifndef COMPAT_32BIT 592 /* 593 * Get the actual dynamic linker pathname from the executable if 594 * possible. (It should always be possible.) That ensures that 595 * gdb will find the right dynamic linker even if a non-standard 596 * one is being used. 597 */ 598 if (obj_main->interp != NULL && 599 strcmp(obj_main->interp, obj_rtld.path) != 0) { 600 free(obj_rtld.path); 601 obj_rtld.path = xstrdup(obj_main->interp); 602 __progname = obj_rtld.path; 603 } 604 #endif 605 606 digest_dynamic(obj_main, 0); 607 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 608 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 609 obj_main->dynsymcount); 610 611 linkmap_add(obj_main); 612 linkmap_add(&obj_rtld); 613 614 /* Link the main program into the list of objects. */ 615 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 616 obj_count++; 617 obj_loads++; 618 619 /* Initialize a fake symbol for resolving undefined weak references. */ 620 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 621 sym_zero.st_shndx = SHN_UNDEF; 622 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 623 624 if (!libmap_disable) 625 libmap_disable = (bool)lm_init(libmap_override); 626 627 dbg("loading LD_PRELOAD libraries"); 628 if (load_preload_objects() == -1) 629 rtld_die(); 630 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 631 632 dbg("loading needed objects"); 633 if (load_needed_objects(obj_main, 0) == -1) 634 rtld_die(); 635 636 /* Make a list of all objects loaded at startup. */ 637 last_interposer = obj_main; 638 TAILQ_FOREACH(obj, &obj_list, next) { 639 if (obj->marker) 640 continue; 641 if (obj->z_interpose && obj != obj_main) { 642 objlist_put_after(&list_main, last_interposer, obj); 643 last_interposer = obj; 644 } else { 645 objlist_push_tail(&list_main, obj); 646 } 647 obj->refcount++; 648 } 649 650 dbg("checking for required versions"); 651 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 652 rtld_die(); 653 654 if (ld_tracing) { /* We're done */ 655 trace_loaded_objects(obj_main); 656 exit(0); 657 } 658 659 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 660 dump_relocations(obj_main); 661 exit (0); 662 } 663 664 /* 665 * Processing tls relocations requires having the tls offsets 666 * initialized. Prepare offsets before starting initial 667 * relocation processing. 668 */ 669 dbg("initializing initial thread local storage offsets"); 670 STAILQ_FOREACH(entry, &list_main, link) { 671 /* 672 * Allocate all the initial objects out of the static TLS 673 * block even if they didn't ask for it. 674 */ 675 allocate_tls_offset(entry->obj); 676 } 677 678 if (relocate_objects(obj_main, 679 ld_bind_now != NULL && *ld_bind_now != '\0', 680 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 681 rtld_die(); 682 683 dbg("doing copy relocations"); 684 if (do_copy_relocations(obj_main) == -1) 685 rtld_die(); 686 687 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 688 dump_relocations(obj_main); 689 exit (0); 690 } 691 692 ifunc_init(aux); 693 694 /* 695 * Setup TLS for main thread. This must be done after the 696 * relocations are processed, since tls initialization section 697 * might be the subject for relocations. 698 */ 699 dbg("initializing initial thread local storage"); 700 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 701 702 dbg("initializing key program variables"); 703 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 704 set_program_var("environ", env); 705 set_program_var("__elf_aux_vector", aux); 706 707 /* Make a list of init functions to call. */ 708 objlist_init(&initlist); 709 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 710 preload_tail, &initlist); 711 712 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 713 714 map_stacks_exec(NULL); 715 716 if (!obj_main->crt_no_init) { 717 /* 718 * Make sure we don't call the main program's init and fini 719 * functions for binaries linked with old crt1 which calls 720 * _init itself. 721 */ 722 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 723 obj_main->preinit_array = obj_main->init_array = 724 obj_main->fini_array = (Elf_Addr)NULL; 725 } 726 727 /* 728 * Execute MD initializers required before we call the objects' 729 * init functions. 730 */ 731 pre_init(); 732 733 wlock_acquire(rtld_bind_lock, &lockstate); 734 735 dbg("resolving ifuncs"); 736 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 737 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 738 rtld_die(); 739 740 if (obj_main->crt_no_init) 741 preinit_main(); 742 objlist_call_init(&initlist, &lockstate); 743 _r_debug_postinit(&obj_main->linkmap); 744 objlist_clear(&initlist); 745 dbg("loading filtees"); 746 TAILQ_FOREACH(obj, &obj_list, next) { 747 if (obj->marker) 748 continue; 749 if (ld_loadfltr || obj->z_loadfltr) 750 load_filtees(obj, 0, &lockstate); 751 } 752 753 dbg("enforcing main obj relro"); 754 if (obj_enforce_relro(obj_main) == -1) 755 rtld_die(); 756 757 lock_release(rtld_bind_lock, &lockstate); 758 759 dbg("transferring control to program entry point = %p", obj_main->entry); 760 761 /* Return the exit procedure and the program entry point. */ 762 *exit_proc = rtld_exit; 763 *objp = obj_main; 764 return (func_ptr_type) obj_main->entry; 765 } 766 767 void * 768 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 769 { 770 void *ptr; 771 Elf_Addr target; 772 773 ptr = (void *)make_function_pointer(def, obj); 774 target = call_ifunc_resolver(ptr); 775 return ((void *)target); 776 } 777 778 /* 779 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 780 * Changes to this function should be applied there as well. 781 */ 782 Elf_Addr 783 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 784 { 785 const Elf_Rel *rel; 786 const Elf_Sym *def; 787 const Obj_Entry *defobj; 788 Elf_Addr *where; 789 Elf_Addr target; 790 RtldLockState lockstate; 791 792 rlock_acquire(rtld_bind_lock, &lockstate); 793 if (sigsetjmp(lockstate.env, 0) != 0) 794 lock_upgrade(rtld_bind_lock, &lockstate); 795 if (obj->pltrel) 796 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 797 else 798 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 799 800 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 801 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 802 NULL, &lockstate); 803 if (def == NULL) 804 rtld_die(); 805 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 806 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 807 else 808 target = (Elf_Addr)(defobj->relocbase + def->st_value); 809 810 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 811 defobj->strtab + def->st_name, basename(obj->path), 812 (void *)target, basename(defobj->path)); 813 814 /* 815 * Write the new contents for the jmpslot. Note that depending on 816 * architecture, the value which we need to return back to the 817 * lazy binding trampoline may or may not be the target 818 * address. The value returned from reloc_jmpslot() is the value 819 * that the trampoline needs. 820 */ 821 target = reloc_jmpslot(where, target, defobj, obj, rel); 822 lock_release(rtld_bind_lock, &lockstate); 823 return target; 824 } 825 826 /* 827 * Error reporting function. Use it like printf. If formats the message 828 * into a buffer, and sets things up so that the next call to dlerror() 829 * will return the message. 830 */ 831 void 832 _rtld_error(const char *fmt, ...) 833 { 834 static char buf[512]; 835 va_list ap; 836 837 va_start(ap, fmt); 838 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 839 error_message = buf; 840 va_end(ap); 841 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 842 } 843 844 /* 845 * Return a dynamically-allocated copy of the current error message, if any. 846 */ 847 static char * 848 errmsg_save(void) 849 { 850 return error_message == NULL ? NULL : xstrdup(error_message); 851 } 852 853 /* 854 * Restore the current error message from a copy which was previously saved 855 * by errmsg_save(). The copy is freed. 856 */ 857 static void 858 errmsg_restore(char *saved_msg) 859 { 860 if (saved_msg == NULL) 861 error_message = NULL; 862 else { 863 _rtld_error("%s", saved_msg); 864 free(saved_msg); 865 } 866 } 867 868 static const char * 869 basename(const char *name) 870 { 871 const char *p = strrchr(name, '/'); 872 return p != NULL ? p + 1 : name; 873 } 874 875 static struct utsname uts; 876 877 static char * 878 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 879 const char *subst, bool may_free) 880 { 881 char *p, *p1, *res, *resp; 882 int subst_len, kw_len, subst_count, old_len, new_len; 883 884 kw_len = strlen(kw); 885 886 /* 887 * First, count the number of the keyword occurrences, to 888 * preallocate the final string. 889 */ 890 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 891 p1 = strstr(p, kw); 892 if (p1 == NULL) 893 break; 894 } 895 896 /* 897 * If the keyword is not found, just return. 898 * 899 * Return non-substituted string if resolution failed. We 900 * cannot do anything more reasonable, the failure mode of the 901 * caller is unresolved library anyway. 902 */ 903 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 904 return (may_free ? real : xstrdup(real)); 905 if (obj != NULL) 906 subst = obj->origin_path; 907 908 /* 909 * There is indeed something to substitute. Calculate the 910 * length of the resulting string, and allocate it. 911 */ 912 subst_len = strlen(subst); 913 old_len = strlen(real); 914 new_len = old_len + (subst_len - kw_len) * subst_count; 915 res = xmalloc(new_len + 1); 916 917 /* 918 * Now, execute the substitution loop. 919 */ 920 for (p = real, resp = res, *resp = '\0';;) { 921 p1 = strstr(p, kw); 922 if (p1 != NULL) { 923 /* Copy the prefix before keyword. */ 924 memcpy(resp, p, p1 - p); 925 resp += p1 - p; 926 /* Keyword replacement. */ 927 memcpy(resp, subst, subst_len); 928 resp += subst_len; 929 *resp = '\0'; 930 p = p1 + kw_len; 931 } else 932 break; 933 } 934 935 /* Copy to the end of string and finish. */ 936 strcat(resp, p); 937 if (may_free) 938 free(real); 939 return (res); 940 } 941 942 static char * 943 origin_subst(Obj_Entry *obj, char *real) 944 { 945 char *res1, *res2, *res3, *res4; 946 947 if (obj == NULL || !trust) 948 return (xstrdup(real)); 949 if (uts.sysname[0] == '\0') { 950 if (uname(&uts) != 0) { 951 _rtld_error("utsname failed: %d", errno); 952 return (NULL); 953 } 954 } 955 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 956 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 957 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 958 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 959 return (res4); 960 } 961 962 void 963 rtld_die(void) 964 { 965 const char *msg = dlerror(); 966 967 if (msg == NULL) 968 msg = "Fatal error"; 969 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 970 rtld_fdputstr(STDERR_FILENO, msg); 971 rtld_fdputchar(STDERR_FILENO, '\n'); 972 _exit(1); 973 } 974 975 /* 976 * Process a shared object's DYNAMIC section, and save the important 977 * information in its Obj_Entry structure. 978 */ 979 static void 980 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 981 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 982 { 983 const Elf_Dyn *dynp; 984 Needed_Entry **needed_tail = &obj->needed; 985 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 986 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 987 const Elf_Hashelt *hashtab; 988 const Elf32_Word *hashval; 989 Elf32_Word bkt, nmaskwords; 990 int bloom_size32; 991 int plttype = DT_REL; 992 993 *dyn_rpath = NULL; 994 *dyn_soname = NULL; 995 *dyn_runpath = NULL; 996 997 obj->bind_now = false; 998 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 999 switch (dynp->d_tag) { 1000 1001 case DT_REL: 1002 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1003 break; 1004 1005 case DT_RELSZ: 1006 obj->relsize = dynp->d_un.d_val; 1007 break; 1008 1009 case DT_RELENT: 1010 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1011 break; 1012 1013 case DT_JMPREL: 1014 obj->pltrel = (const Elf_Rel *) 1015 (obj->relocbase + dynp->d_un.d_ptr); 1016 break; 1017 1018 case DT_PLTRELSZ: 1019 obj->pltrelsize = dynp->d_un.d_val; 1020 break; 1021 1022 case DT_RELA: 1023 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1024 break; 1025 1026 case DT_RELASZ: 1027 obj->relasize = dynp->d_un.d_val; 1028 break; 1029 1030 case DT_RELAENT: 1031 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1032 break; 1033 1034 case DT_PLTREL: 1035 plttype = dynp->d_un.d_val; 1036 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1037 break; 1038 1039 case DT_SYMTAB: 1040 obj->symtab = (const Elf_Sym *) 1041 (obj->relocbase + dynp->d_un.d_ptr); 1042 break; 1043 1044 case DT_SYMENT: 1045 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1046 break; 1047 1048 case DT_STRTAB: 1049 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1050 break; 1051 1052 case DT_STRSZ: 1053 obj->strsize = dynp->d_un.d_val; 1054 break; 1055 1056 case DT_VERNEED: 1057 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1058 dynp->d_un.d_val); 1059 break; 1060 1061 case DT_VERNEEDNUM: 1062 obj->verneednum = dynp->d_un.d_val; 1063 break; 1064 1065 case DT_VERDEF: 1066 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1067 dynp->d_un.d_val); 1068 break; 1069 1070 case DT_VERDEFNUM: 1071 obj->verdefnum = dynp->d_un.d_val; 1072 break; 1073 1074 case DT_VERSYM: 1075 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1076 dynp->d_un.d_val); 1077 break; 1078 1079 case DT_HASH: 1080 { 1081 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1082 dynp->d_un.d_ptr); 1083 obj->nbuckets = hashtab[0]; 1084 obj->nchains = hashtab[1]; 1085 obj->buckets = hashtab + 2; 1086 obj->chains = obj->buckets + obj->nbuckets; 1087 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1088 obj->buckets != NULL; 1089 } 1090 break; 1091 1092 case DT_GNU_HASH: 1093 { 1094 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1095 dynp->d_un.d_ptr); 1096 obj->nbuckets_gnu = hashtab[0]; 1097 obj->symndx_gnu = hashtab[1]; 1098 nmaskwords = hashtab[2]; 1099 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1100 obj->maskwords_bm_gnu = nmaskwords - 1; 1101 obj->shift2_gnu = hashtab[3]; 1102 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1103 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1104 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1105 obj->symndx_gnu; 1106 /* Number of bitmask words is required to be power of 2 */ 1107 obj->valid_hash_gnu = powerof2(nmaskwords) && 1108 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1109 } 1110 break; 1111 1112 case DT_NEEDED: 1113 if (!obj->rtld) { 1114 Needed_Entry *nep = NEW(Needed_Entry); 1115 nep->name = dynp->d_un.d_val; 1116 nep->obj = NULL; 1117 nep->next = NULL; 1118 1119 *needed_tail = nep; 1120 needed_tail = &nep->next; 1121 } 1122 break; 1123 1124 case DT_FILTER: 1125 if (!obj->rtld) { 1126 Needed_Entry *nep = NEW(Needed_Entry); 1127 nep->name = dynp->d_un.d_val; 1128 nep->obj = NULL; 1129 nep->next = NULL; 1130 1131 *needed_filtees_tail = nep; 1132 needed_filtees_tail = &nep->next; 1133 } 1134 break; 1135 1136 case DT_AUXILIARY: 1137 if (!obj->rtld) { 1138 Needed_Entry *nep = NEW(Needed_Entry); 1139 nep->name = dynp->d_un.d_val; 1140 nep->obj = NULL; 1141 nep->next = NULL; 1142 1143 *needed_aux_filtees_tail = nep; 1144 needed_aux_filtees_tail = &nep->next; 1145 } 1146 break; 1147 1148 case DT_PLTGOT: 1149 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1150 break; 1151 1152 case DT_TEXTREL: 1153 obj->textrel = true; 1154 break; 1155 1156 case DT_SYMBOLIC: 1157 obj->symbolic = true; 1158 break; 1159 1160 case DT_RPATH: 1161 /* 1162 * We have to wait until later to process this, because we 1163 * might not have gotten the address of the string table yet. 1164 */ 1165 *dyn_rpath = dynp; 1166 break; 1167 1168 case DT_SONAME: 1169 *dyn_soname = dynp; 1170 break; 1171 1172 case DT_RUNPATH: 1173 *dyn_runpath = dynp; 1174 break; 1175 1176 case DT_INIT: 1177 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1178 break; 1179 1180 case DT_PREINIT_ARRAY: 1181 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1182 break; 1183 1184 case DT_PREINIT_ARRAYSZ: 1185 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1186 break; 1187 1188 case DT_INIT_ARRAY: 1189 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1190 break; 1191 1192 case DT_INIT_ARRAYSZ: 1193 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1194 break; 1195 1196 case DT_FINI: 1197 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1198 break; 1199 1200 case DT_FINI_ARRAY: 1201 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1202 break; 1203 1204 case DT_FINI_ARRAYSZ: 1205 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1206 break; 1207 1208 /* 1209 * Don't process DT_DEBUG on MIPS as the dynamic section 1210 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1211 */ 1212 1213 #ifndef __mips__ 1214 case DT_DEBUG: 1215 if (!early) 1216 dbg("Filling in DT_DEBUG entry"); 1217 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1218 break; 1219 #endif 1220 1221 case DT_FLAGS: 1222 if (dynp->d_un.d_val & DF_ORIGIN) 1223 obj->z_origin = true; 1224 if (dynp->d_un.d_val & DF_SYMBOLIC) 1225 obj->symbolic = true; 1226 if (dynp->d_un.d_val & DF_TEXTREL) 1227 obj->textrel = true; 1228 if (dynp->d_un.d_val & DF_BIND_NOW) 1229 obj->bind_now = true; 1230 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1231 ;*/ 1232 break; 1233 #ifdef __mips__ 1234 case DT_MIPS_LOCAL_GOTNO: 1235 obj->local_gotno = dynp->d_un.d_val; 1236 break; 1237 1238 case DT_MIPS_SYMTABNO: 1239 obj->symtabno = dynp->d_un.d_val; 1240 break; 1241 1242 case DT_MIPS_GOTSYM: 1243 obj->gotsym = dynp->d_un.d_val; 1244 break; 1245 1246 case DT_MIPS_RLD_MAP: 1247 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1248 break; 1249 1250 case DT_MIPS_PLTGOT: 1251 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase + 1252 dynp->d_un.d_ptr); 1253 break; 1254 1255 #endif 1256 1257 #ifdef __powerpc64__ 1258 case DT_PPC64_GLINK: 1259 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1260 break; 1261 #endif 1262 1263 case DT_FLAGS_1: 1264 if (dynp->d_un.d_val & DF_1_NOOPEN) 1265 obj->z_noopen = true; 1266 if (dynp->d_un.d_val & DF_1_ORIGIN) 1267 obj->z_origin = true; 1268 if (dynp->d_un.d_val & DF_1_GLOBAL) 1269 obj->z_global = true; 1270 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1271 obj->bind_now = true; 1272 if (dynp->d_un.d_val & DF_1_NODELETE) 1273 obj->z_nodelete = true; 1274 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1275 obj->z_loadfltr = true; 1276 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1277 obj->z_interpose = true; 1278 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1279 obj->z_nodeflib = true; 1280 break; 1281 1282 default: 1283 if (!early) { 1284 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1285 (long)dynp->d_tag); 1286 } 1287 break; 1288 } 1289 } 1290 1291 obj->traced = false; 1292 1293 if (plttype == DT_RELA) { 1294 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1295 obj->pltrel = NULL; 1296 obj->pltrelasize = obj->pltrelsize; 1297 obj->pltrelsize = 0; 1298 } 1299 1300 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1301 if (obj->valid_hash_sysv) 1302 obj->dynsymcount = obj->nchains; 1303 else if (obj->valid_hash_gnu) { 1304 obj->dynsymcount = 0; 1305 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1306 if (obj->buckets_gnu[bkt] == 0) 1307 continue; 1308 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1309 do 1310 obj->dynsymcount++; 1311 while ((*hashval++ & 1u) == 0); 1312 } 1313 obj->dynsymcount += obj->symndx_gnu; 1314 } 1315 } 1316 1317 static bool 1318 obj_resolve_origin(Obj_Entry *obj) 1319 { 1320 1321 if (obj->origin_path != NULL) 1322 return (true); 1323 obj->origin_path = xmalloc(PATH_MAX); 1324 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1325 } 1326 1327 static void 1328 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1329 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1330 { 1331 1332 if (obj->z_origin && !obj_resolve_origin(obj)) 1333 rtld_die(); 1334 1335 if (dyn_runpath != NULL) { 1336 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1337 obj->runpath = origin_subst(obj, obj->runpath); 1338 } else if (dyn_rpath != NULL) { 1339 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1340 obj->rpath = origin_subst(obj, obj->rpath); 1341 } 1342 if (dyn_soname != NULL) 1343 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1344 } 1345 1346 static void 1347 digest_dynamic(Obj_Entry *obj, int early) 1348 { 1349 const Elf_Dyn *dyn_rpath; 1350 const Elf_Dyn *dyn_soname; 1351 const Elf_Dyn *dyn_runpath; 1352 1353 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1354 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1355 } 1356 1357 /* 1358 * Process a shared object's program header. This is used only for the 1359 * main program, when the kernel has already loaded the main program 1360 * into memory before calling the dynamic linker. It creates and 1361 * returns an Obj_Entry structure. 1362 */ 1363 static Obj_Entry * 1364 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1365 { 1366 Obj_Entry *obj; 1367 const Elf_Phdr *phlimit = phdr + phnum; 1368 const Elf_Phdr *ph; 1369 Elf_Addr note_start, note_end; 1370 int nsegs = 0; 1371 1372 obj = obj_new(); 1373 for (ph = phdr; ph < phlimit; ph++) { 1374 if (ph->p_type != PT_PHDR) 1375 continue; 1376 1377 obj->phdr = phdr; 1378 obj->phsize = ph->p_memsz; 1379 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1380 break; 1381 } 1382 1383 obj->stack_flags = PF_X | PF_R | PF_W; 1384 1385 for (ph = phdr; ph < phlimit; ph++) { 1386 switch (ph->p_type) { 1387 1388 case PT_INTERP: 1389 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1390 break; 1391 1392 case PT_LOAD: 1393 if (nsegs == 0) { /* First load segment */ 1394 obj->vaddrbase = trunc_page(ph->p_vaddr); 1395 obj->mapbase = obj->vaddrbase + obj->relocbase; 1396 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1397 obj->vaddrbase; 1398 } else { /* Last load segment */ 1399 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1400 obj->vaddrbase; 1401 } 1402 nsegs++; 1403 break; 1404 1405 case PT_DYNAMIC: 1406 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1407 break; 1408 1409 case PT_TLS: 1410 obj->tlsindex = 1; 1411 obj->tlssize = ph->p_memsz; 1412 obj->tlsalign = ph->p_align; 1413 obj->tlsinitsize = ph->p_filesz; 1414 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1415 break; 1416 1417 case PT_GNU_STACK: 1418 obj->stack_flags = ph->p_flags; 1419 break; 1420 1421 case PT_GNU_RELRO: 1422 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1423 obj->relro_size = round_page(ph->p_memsz); 1424 break; 1425 1426 case PT_NOTE: 1427 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1428 note_end = note_start + ph->p_filesz; 1429 digest_notes(obj, note_start, note_end); 1430 break; 1431 } 1432 } 1433 if (nsegs < 1) { 1434 _rtld_error("%s: too few PT_LOAD segments", path); 1435 return NULL; 1436 } 1437 1438 obj->entry = entry; 1439 return obj; 1440 } 1441 1442 void 1443 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1444 { 1445 const Elf_Note *note; 1446 const char *note_name; 1447 uintptr_t p; 1448 1449 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1450 note = (const Elf_Note *)((const char *)(note + 1) + 1451 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1452 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1453 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1454 note->n_descsz != sizeof(int32_t)) 1455 continue; 1456 if (note->n_type != NT_FREEBSD_ABI_TAG && 1457 note->n_type != NT_FREEBSD_FEATURE_CTL && 1458 note->n_type != NT_FREEBSD_NOINIT_TAG) 1459 continue; 1460 note_name = (const char *)(note + 1); 1461 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1462 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1463 continue; 1464 switch (note->n_type) { 1465 case NT_FREEBSD_ABI_TAG: 1466 /* FreeBSD osrel note */ 1467 p = (uintptr_t)(note + 1); 1468 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1469 obj->osrel = *(const int32_t *)(p); 1470 dbg("note osrel %d", obj->osrel); 1471 break; 1472 case NT_FREEBSD_FEATURE_CTL: 1473 /* FreeBSD ABI feature control note */ 1474 p = (uintptr_t)(note + 1); 1475 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1476 obj->fctl0 = *(const uint32_t *)(p); 1477 dbg("note fctl0 %#x", obj->fctl0); 1478 break; 1479 case NT_FREEBSD_NOINIT_TAG: 1480 /* FreeBSD 'crt does not call init' note */ 1481 obj->crt_no_init = true; 1482 dbg("note crt_no_init"); 1483 break; 1484 } 1485 } 1486 } 1487 1488 static Obj_Entry * 1489 dlcheck(void *handle) 1490 { 1491 Obj_Entry *obj; 1492 1493 TAILQ_FOREACH(obj, &obj_list, next) { 1494 if (obj == (Obj_Entry *) handle) 1495 break; 1496 } 1497 1498 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1499 _rtld_error("Invalid shared object handle %p", handle); 1500 return NULL; 1501 } 1502 return obj; 1503 } 1504 1505 /* 1506 * If the given object is already in the donelist, return true. Otherwise 1507 * add the object to the list and return false. 1508 */ 1509 static bool 1510 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1511 { 1512 unsigned int i; 1513 1514 for (i = 0; i < dlp->num_used; i++) 1515 if (dlp->objs[i] == obj) 1516 return true; 1517 /* 1518 * Our donelist allocation should always be sufficient. But if 1519 * our threads locking isn't working properly, more shared objects 1520 * could have been loaded since we allocated the list. That should 1521 * never happen, but we'll handle it properly just in case it does. 1522 */ 1523 if (dlp->num_used < dlp->num_alloc) 1524 dlp->objs[dlp->num_used++] = obj; 1525 return false; 1526 } 1527 1528 /* 1529 * Hash function for symbol table lookup. Don't even think about changing 1530 * this. It is specified by the System V ABI. 1531 */ 1532 unsigned long 1533 elf_hash(const char *name) 1534 { 1535 const unsigned char *p = (const unsigned char *) name; 1536 unsigned long h = 0; 1537 unsigned long g; 1538 1539 while (*p != '\0') { 1540 h = (h << 4) + *p++; 1541 if ((g = h & 0xf0000000) != 0) 1542 h ^= g >> 24; 1543 h &= ~g; 1544 } 1545 return h; 1546 } 1547 1548 /* 1549 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1550 * unsigned in case it's implemented with a wider type. 1551 */ 1552 static uint32_t 1553 gnu_hash(const char *s) 1554 { 1555 uint32_t h; 1556 unsigned char c; 1557 1558 h = 5381; 1559 for (c = *s; c != '\0'; c = *++s) 1560 h = h * 33 + c; 1561 return (h & 0xffffffff); 1562 } 1563 1564 1565 /* 1566 * Find the library with the given name, and return its full pathname. 1567 * The returned string is dynamically allocated. Generates an error 1568 * message and returns NULL if the library cannot be found. 1569 * 1570 * If the second argument is non-NULL, then it refers to an already- 1571 * loaded shared object, whose library search path will be searched. 1572 * 1573 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1574 * descriptor (which is close-on-exec) will be passed out via the third 1575 * argument. 1576 * 1577 * The search order is: 1578 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1579 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1580 * LD_LIBRARY_PATH 1581 * DT_RUNPATH in the referencing file 1582 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1583 * from list) 1584 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1585 * 1586 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1587 */ 1588 static char * 1589 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1590 { 1591 char *name, *pathname, *refobj_path; 1592 bool nodeflib, objgiven; 1593 1594 objgiven = refobj != NULL; 1595 1596 if (libmap_disable || !objgiven || 1597 (name = lm_find(refobj->path, xname)) == NULL) 1598 name = (char *)xname; 1599 1600 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1601 if (name[0] != '/' && !trust) { 1602 _rtld_error("Absolute pathname required " 1603 "for shared object \"%s\"", name); 1604 return (NULL); 1605 } 1606 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1607 __DECONST(char *, name))); 1608 } 1609 1610 dbg(" Searching for \"%s\"", name); 1611 refobj_path = objgiven ? refobj->path : NULL; 1612 1613 /* 1614 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1615 * back to pre-conforming behaviour if user requested so with 1616 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1617 * nodeflib. 1618 */ 1619 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1620 pathname = search_library_path(name, ld_library_path, 1621 refobj_path, fdp); 1622 if (pathname != NULL) 1623 return (pathname); 1624 if (refobj != NULL) { 1625 pathname = search_library_path(name, refobj->rpath, 1626 refobj_path, fdp); 1627 if (pathname != NULL) 1628 return (pathname); 1629 } 1630 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1631 if (pathname != NULL) 1632 return (pathname); 1633 pathname = search_library_path(name, gethints(false), 1634 refobj_path, fdp); 1635 if (pathname != NULL) 1636 return (pathname); 1637 pathname = search_library_path(name, ld_standard_library_path, 1638 refobj_path, fdp); 1639 if (pathname != NULL) 1640 return (pathname); 1641 } else { 1642 nodeflib = objgiven ? refobj->z_nodeflib : false; 1643 if (objgiven) { 1644 pathname = search_library_path(name, refobj->rpath, 1645 refobj->path, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 } 1649 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1650 pathname = search_library_path(name, obj_main->rpath, 1651 refobj_path, fdp); 1652 if (pathname != NULL) 1653 return (pathname); 1654 } 1655 pathname = search_library_path(name, ld_library_path, 1656 refobj_path, fdp); 1657 if (pathname != NULL) 1658 return (pathname); 1659 if (objgiven) { 1660 pathname = search_library_path(name, refobj->runpath, 1661 refobj_path, fdp); 1662 if (pathname != NULL) 1663 return (pathname); 1664 } 1665 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 pathname = search_library_path(name, gethints(nodeflib), 1669 refobj_path, fdp); 1670 if (pathname != NULL) 1671 return (pathname); 1672 if (objgiven && !nodeflib) { 1673 pathname = search_library_path(name, 1674 ld_standard_library_path, refobj_path, fdp); 1675 if (pathname != NULL) 1676 return (pathname); 1677 } 1678 } 1679 1680 if (objgiven && refobj->path != NULL) { 1681 _rtld_error("Shared object \"%s\" not found, " 1682 "required by \"%s\"", name, basename(refobj->path)); 1683 } else { 1684 _rtld_error("Shared object \"%s\" not found", name); 1685 } 1686 return (NULL); 1687 } 1688 1689 /* 1690 * Given a symbol number in a referencing object, find the corresponding 1691 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1692 * no definition was found. Returns a pointer to the Obj_Entry of the 1693 * defining object via the reference parameter DEFOBJ_OUT. 1694 */ 1695 const Elf_Sym * 1696 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1697 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1698 RtldLockState *lockstate) 1699 { 1700 const Elf_Sym *ref; 1701 const Elf_Sym *def; 1702 const Obj_Entry *defobj; 1703 const Ver_Entry *ve; 1704 SymLook req; 1705 const char *name; 1706 int res; 1707 1708 /* 1709 * If we have already found this symbol, get the information from 1710 * the cache. 1711 */ 1712 if (symnum >= refobj->dynsymcount) 1713 return NULL; /* Bad object */ 1714 if (cache != NULL && cache[symnum].sym != NULL) { 1715 *defobj_out = cache[symnum].obj; 1716 return cache[symnum].sym; 1717 } 1718 1719 ref = refobj->symtab + symnum; 1720 name = refobj->strtab + ref->st_name; 1721 def = NULL; 1722 defobj = NULL; 1723 ve = NULL; 1724 1725 /* 1726 * We don't have to do a full scale lookup if the symbol is local. 1727 * We know it will bind to the instance in this load module; to 1728 * which we already have a pointer (ie ref). By not doing a lookup, 1729 * we not only improve performance, but it also avoids unresolvable 1730 * symbols when local symbols are not in the hash table. This has 1731 * been seen with the ia64 toolchain. 1732 */ 1733 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1734 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1735 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1736 symnum); 1737 } 1738 symlook_init(&req, name); 1739 req.flags = flags; 1740 ve = req.ventry = fetch_ventry(refobj, symnum); 1741 req.lockstate = lockstate; 1742 res = symlook_default(&req, refobj); 1743 if (res == 0) { 1744 def = req.sym_out; 1745 defobj = req.defobj_out; 1746 } 1747 } else { 1748 def = ref; 1749 defobj = refobj; 1750 } 1751 1752 /* 1753 * If we found no definition and the reference is weak, treat the 1754 * symbol as having the value zero. 1755 */ 1756 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1757 def = &sym_zero; 1758 defobj = obj_main; 1759 } 1760 1761 if (def != NULL) { 1762 *defobj_out = defobj; 1763 /* Record the information in the cache to avoid subsequent lookups. */ 1764 if (cache != NULL) { 1765 cache[symnum].sym = def; 1766 cache[symnum].obj = defobj; 1767 } 1768 } else { 1769 if (refobj != &obj_rtld) 1770 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1771 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1772 } 1773 return def; 1774 } 1775 1776 /* 1777 * Return the search path from the ldconfig hints file, reading it if 1778 * necessary. If nostdlib is true, then the default search paths are 1779 * not added to result. 1780 * 1781 * Returns NULL if there are problems with the hints file, 1782 * or if the search path there is empty. 1783 */ 1784 static const char * 1785 gethints(bool nostdlib) 1786 { 1787 static char *hints, *filtered_path; 1788 static struct elfhints_hdr hdr; 1789 struct fill_search_info_args sargs, hargs; 1790 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1791 struct dl_serpath *SLPpath, *hintpath; 1792 char *p; 1793 struct stat hint_stat; 1794 unsigned int SLPndx, hintndx, fndx, fcount; 1795 int fd; 1796 size_t flen; 1797 uint32_t dl; 1798 bool skip; 1799 1800 /* First call, read the hints file */ 1801 if (hints == NULL) { 1802 /* Keep from trying again in case the hints file is bad. */ 1803 hints = ""; 1804 1805 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1806 return (NULL); 1807 1808 /* 1809 * Check of hdr.dirlistlen value against type limit 1810 * intends to pacify static analyzers. Further 1811 * paranoia leads to checks that dirlist is fully 1812 * contained in the file range. 1813 */ 1814 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1815 hdr.magic != ELFHINTS_MAGIC || 1816 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1817 fstat(fd, &hint_stat) == -1) { 1818 cleanup1: 1819 close(fd); 1820 hdr.dirlistlen = 0; 1821 return (NULL); 1822 } 1823 dl = hdr.strtab; 1824 if (dl + hdr.dirlist < dl) 1825 goto cleanup1; 1826 dl += hdr.dirlist; 1827 if (dl + hdr.dirlistlen < dl) 1828 goto cleanup1; 1829 dl += hdr.dirlistlen; 1830 if (dl > hint_stat.st_size) 1831 goto cleanup1; 1832 p = xmalloc(hdr.dirlistlen + 1); 1833 if (pread(fd, p, hdr.dirlistlen + 1, 1834 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1835 p[hdr.dirlistlen] != '\0') { 1836 free(p); 1837 goto cleanup1; 1838 } 1839 hints = p; 1840 close(fd); 1841 } 1842 1843 /* 1844 * If caller agreed to receive list which includes the default 1845 * paths, we are done. Otherwise, if we still did not 1846 * calculated filtered result, do it now. 1847 */ 1848 if (!nostdlib) 1849 return (hints[0] != '\0' ? hints : NULL); 1850 if (filtered_path != NULL) 1851 goto filt_ret; 1852 1853 /* 1854 * Obtain the list of all configured search paths, and the 1855 * list of the default paths. 1856 * 1857 * First estimate the size of the results. 1858 */ 1859 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1860 smeta.dls_cnt = 0; 1861 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1862 hmeta.dls_cnt = 0; 1863 1864 sargs.request = RTLD_DI_SERINFOSIZE; 1865 sargs.serinfo = &smeta; 1866 hargs.request = RTLD_DI_SERINFOSIZE; 1867 hargs.serinfo = &hmeta; 1868 1869 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1870 &sargs); 1871 path_enumerate(hints, fill_search_info, NULL, &hargs); 1872 1873 SLPinfo = xmalloc(smeta.dls_size); 1874 hintinfo = xmalloc(hmeta.dls_size); 1875 1876 /* 1877 * Next fetch both sets of paths. 1878 */ 1879 sargs.request = RTLD_DI_SERINFO; 1880 sargs.serinfo = SLPinfo; 1881 sargs.serpath = &SLPinfo->dls_serpath[0]; 1882 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1883 1884 hargs.request = RTLD_DI_SERINFO; 1885 hargs.serinfo = hintinfo; 1886 hargs.serpath = &hintinfo->dls_serpath[0]; 1887 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1888 1889 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1890 &sargs); 1891 path_enumerate(hints, fill_search_info, NULL, &hargs); 1892 1893 /* 1894 * Now calculate the difference between two sets, by excluding 1895 * standard paths from the full set. 1896 */ 1897 fndx = 0; 1898 fcount = 0; 1899 filtered_path = xmalloc(hdr.dirlistlen + 1); 1900 hintpath = &hintinfo->dls_serpath[0]; 1901 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1902 skip = false; 1903 SLPpath = &SLPinfo->dls_serpath[0]; 1904 /* 1905 * Check each standard path against current. 1906 */ 1907 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1908 /* matched, skip the path */ 1909 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1910 skip = true; 1911 break; 1912 } 1913 } 1914 if (skip) 1915 continue; 1916 /* 1917 * Not matched against any standard path, add the path 1918 * to result. Separate consequtive paths with ':'. 1919 */ 1920 if (fcount > 0) { 1921 filtered_path[fndx] = ':'; 1922 fndx++; 1923 } 1924 fcount++; 1925 flen = strlen(hintpath->dls_name); 1926 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1927 fndx += flen; 1928 } 1929 filtered_path[fndx] = '\0'; 1930 1931 free(SLPinfo); 1932 free(hintinfo); 1933 1934 filt_ret: 1935 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1936 } 1937 1938 static void 1939 init_dag(Obj_Entry *root) 1940 { 1941 const Needed_Entry *needed; 1942 const Objlist_Entry *elm; 1943 DoneList donelist; 1944 1945 if (root->dag_inited) 1946 return; 1947 donelist_init(&donelist); 1948 1949 /* Root object belongs to own DAG. */ 1950 objlist_push_tail(&root->dldags, root); 1951 objlist_push_tail(&root->dagmembers, root); 1952 donelist_check(&donelist, root); 1953 1954 /* 1955 * Add dependencies of root object to DAG in breadth order 1956 * by exploiting the fact that each new object get added 1957 * to the tail of the dagmembers list. 1958 */ 1959 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1960 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1961 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1962 continue; 1963 objlist_push_tail(&needed->obj->dldags, root); 1964 objlist_push_tail(&root->dagmembers, needed->obj); 1965 } 1966 } 1967 root->dag_inited = true; 1968 } 1969 1970 static void 1971 init_marker(Obj_Entry *marker) 1972 { 1973 1974 bzero(marker, sizeof(*marker)); 1975 marker->marker = true; 1976 } 1977 1978 Obj_Entry * 1979 globallist_curr(const Obj_Entry *obj) 1980 { 1981 1982 for (;;) { 1983 if (obj == NULL) 1984 return (NULL); 1985 if (!obj->marker) 1986 return (__DECONST(Obj_Entry *, obj)); 1987 obj = TAILQ_PREV(obj, obj_entry_q, next); 1988 } 1989 } 1990 1991 Obj_Entry * 1992 globallist_next(const Obj_Entry *obj) 1993 { 1994 1995 for (;;) { 1996 obj = TAILQ_NEXT(obj, next); 1997 if (obj == NULL) 1998 return (NULL); 1999 if (!obj->marker) 2000 return (__DECONST(Obj_Entry *, obj)); 2001 } 2002 } 2003 2004 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2005 static void 2006 hold_object(Obj_Entry *obj) 2007 { 2008 2009 obj->holdcount++; 2010 } 2011 2012 static void 2013 unhold_object(Obj_Entry *obj) 2014 { 2015 2016 assert(obj->holdcount > 0); 2017 if (--obj->holdcount == 0 && obj->unholdfree) 2018 release_object(obj); 2019 } 2020 2021 static void 2022 process_z(Obj_Entry *root) 2023 { 2024 const Objlist_Entry *elm; 2025 Obj_Entry *obj; 2026 2027 /* 2028 * Walk over object DAG and process every dependent object 2029 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2030 * to grow their own DAG. 2031 * 2032 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2033 * symlook_global() to work. 2034 * 2035 * For DF_1_NODELETE, the DAG should have its reference upped. 2036 */ 2037 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2038 obj = elm->obj; 2039 if (obj == NULL) 2040 continue; 2041 if (obj->z_nodelete && !obj->ref_nodel) { 2042 dbg("obj %s -z nodelete", obj->path); 2043 init_dag(obj); 2044 ref_dag(obj); 2045 obj->ref_nodel = true; 2046 } 2047 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2048 dbg("obj %s -z global", obj->path); 2049 objlist_push_tail(&list_global, obj); 2050 init_dag(obj); 2051 } 2052 } 2053 } 2054 /* 2055 * Initialize the dynamic linker. The argument is the address at which 2056 * the dynamic linker has been mapped into memory. The primary task of 2057 * this function is to relocate the dynamic linker. 2058 */ 2059 static void 2060 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2061 { 2062 Obj_Entry objtmp; /* Temporary rtld object */ 2063 const Elf_Ehdr *ehdr; 2064 const Elf_Dyn *dyn_rpath; 2065 const Elf_Dyn *dyn_soname; 2066 const Elf_Dyn *dyn_runpath; 2067 2068 #ifdef RTLD_INIT_PAGESIZES_EARLY 2069 /* The page size is required by the dynamic memory allocator. */ 2070 init_pagesizes(aux_info); 2071 #endif 2072 2073 /* 2074 * Conjure up an Obj_Entry structure for the dynamic linker. 2075 * 2076 * The "path" member can't be initialized yet because string constants 2077 * cannot yet be accessed. Below we will set it correctly. 2078 */ 2079 memset(&objtmp, 0, sizeof(objtmp)); 2080 objtmp.path = NULL; 2081 objtmp.rtld = true; 2082 objtmp.mapbase = mapbase; 2083 #ifdef PIC 2084 objtmp.relocbase = mapbase; 2085 #endif 2086 2087 objtmp.dynamic = rtld_dynamic(&objtmp); 2088 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2089 assert(objtmp.needed == NULL); 2090 #if !defined(__mips__) 2091 /* MIPS has a bogus DT_TEXTREL. */ 2092 assert(!objtmp.textrel); 2093 #endif 2094 /* 2095 * Temporarily put the dynamic linker entry into the object list, so 2096 * that symbols can be found. 2097 */ 2098 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2099 2100 ehdr = (Elf_Ehdr *)mapbase; 2101 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2102 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2103 2104 /* Initialize the object list. */ 2105 TAILQ_INIT(&obj_list); 2106 2107 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2108 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2109 2110 #ifndef RTLD_INIT_PAGESIZES_EARLY 2111 /* The page size is required by the dynamic memory allocator. */ 2112 init_pagesizes(aux_info); 2113 #endif 2114 2115 if (aux_info[AT_OSRELDATE] != NULL) 2116 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2117 2118 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2119 2120 /* Replace the path with a dynamically allocated copy. */ 2121 obj_rtld.path = xstrdup(ld_path_rtld); 2122 2123 r_debug.r_brk = r_debug_state; 2124 r_debug.r_state = RT_CONSISTENT; 2125 } 2126 2127 /* 2128 * Retrieve the array of supported page sizes. The kernel provides the page 2129 * sizes in increasing order. 2130 */ 2131 static void 2132 init_pagesizes(Elf_Auxinfo **aux_info) 2133 { 2134 static size_t psa[MAXPAGESIZES]; 2135 int mib[2]; 2136 size_t len, size; 2137 2138 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2139 NULL) { 2140 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2141 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2142 } else { 2143 len = 2; 2144 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2145 size = sizeof(psa); 2146 else { 2147 /* As a fallback, retrieve the base page size. */ 2148 size = sizeof(psa[0]); 2149 if (aux_info[AT_PAGESZ] != NULL) { 2150 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2151 goto psa_filled; 2152 } else { 2153 mib[0] = CTL_HW; 2154 mib[1] = HW_PAGESIZE; 2155 len = 2; 2156 } 2157 } 2158 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2159 _rtld_error("sysctl for hw.pagesize(s) failed"); 2160 rtld_die(); 2161 } 2162 psa_filled: 2163 pagesizes = psa; 2164 } 2165 npagesizes = size / sizeof(pagesizes[0]); 2166 /* Discard any invalid entries at the end of the array. */ 2167 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2168 npagesizes--; 2169 } 2170 2171 /* 2172 * Add the init functions from a needed object list (and its recursive 2173 * needed objects) to "list". This is not used directly; it is a helper 2174 * function for initlist_add_objects(). The write lock must be held 2175 * when this function is called. 2176 */ 2177 static void 2178 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2179 { 2180 /* Recursively process the successor needed objects. */ 2181 if (needed->next != NULL) 2182 initlist_add_neededs(needed->next, list); 2183 2184 /* Process the current needed object. */ 2185 if (needed->obj != NULL) 2186 initlist_add_objects(needed->obj, needed->obj, list); 2187 } 2188 2189 /* 2190 * Scan all of the DAGs rooted in the range of objects from "obj" to 2191 * "tail" and add their init functions to "list". This recurses over 2192 * the DAGs and ensure the proper init ordering such that each object's 2193 * needed libraries are initialized before the object itself. At the 2194 * same time, this function adds the objects to the global finalization 2195 * list "list_fini" in the opposite order. The write lock must be 2196 * held when this function is called. 2197 */ 2198 static void 2199 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2200 { 2201 Obj_Entry *nobj; 2202 2203 if (obj->init_scanned || obj->init_done) 2204 return; 2205 obj->init_scanned = true; 2206 2207 /* Recursively process the successor objects. */ 2208 nobj = globallist_next(obj); 2209 if (nobj != NULL && obj != tail) 2210 initlist_add_objects(nobj, tail, list); 2211 2212 /* Recursively process the needed objects. */ 2213 if (obj->needed != NULL) 2214 initlist_add_neededs(obj->needed, list); 2215 if (obj->needed_filtees != NULL) 2216 initlist_add_neededs(obj->needed_filtees, list); 2217 if (obj->needed_aux_filtees != NULL) 2218 initlist_add_neededs(obj->needed_aux_filtees, list); 2219 2220 /* Add the object to the init list. */ 2221 objlist_push_tail(list, obj); 2222 2223 /* Add the object to the global fini list in the reverse order. */ 2224 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2225 && !obj->on_fini_list) { 2226 objlist_push_head(&list_fini, obj); 2227 obj->on_fini_list = true; 2228 } 2229 } 2230 2231 #ifndef FPTR_TARGET 2232 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2233 #endif 2234 2235 static void 2236 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2237 { 2238 Needed_Entry *needed, *needed1; 2239 2240 for (needed = n; needed != NULL; needed = needed->next) { 2241 if (needed->obj != NULL) { 2242 dlclose_locked(needed->obj, lockstate); 2243 needed->obj = NULL; 2244 } 2245 } 2246 for (needed = n; needed != NULL; needed = needed1) { 2247 needed1 = needed->next; 2248 free(needed); 2249 } 2250 } 2251 2252 static void 2253 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2254 { 2255 2256 free_needed_filtees(obj->needed_filtees, lockstate); 2257 obj->needed_filtees = NULL; 2258 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2259 obj->needed_aux_filtees = NULL; 2260 obj->filtees_loaded = false; 2261 } 2262 2263 static void 2264 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2265 RtldLockState *lockstate) 2266 { 2267 2268 for (; needed != NULL; needed = needed->next) { 2269 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2270 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2271 RTLD_LOCAL, lockstate); 2272 } 2273 } 2274 2275 static void 2276 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2277 { 2278 2279 lock_restart_for_upgrade(lockstate); 2280 if (!obj->filtees_loaded) { 2281 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2282 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2283 obj->filtees_loaded = true; 2284 } 2285 } 2286 2287 static int 2288 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2289 { 2290 Obj_Entry *obj1; 2291 2292 for (; needed != NULL; needed = needed->next) { 2293 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2294 flags & ~RTLD_LO_NOLOAD); 2295 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2296 return (-1); 2297 } 2298 return (0); 2299 } 2300 2301 /* 2302 * Given a shared object, traverse its list of needed objects, and load 2303 * each of them. Returns 0 on success. Generates an error message and 2304 * returns -1 on failure. 2305 */ 2306 static int 2307 load_needed_objects(Obj_Entry *first, int flags) 2308 { 2309 Obj_Entry *obj; 2310 2311 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2312 if (obj->marker) 2313 continue; 2314 if (process_needed(obj, obj->needed, flags) == -1) 2315 return (-1); 2316 } 2317 return (0); 2318 } 2319 2320 static int 2321 load_preload_objects(void) 2322 { 2323 char *p = ld_preload; 2324 Obj_Entry *obj; 2325 static const char delim[] = " \t:;"; 2326 2327 if (p == NULL) 2328 return 0; 2329 2330 p += strspn(p, delim); 2331 while (*p != '\0') { 2332 size_t len = strcspn(p, delim); 2333 char savech; 2334 2335 savech = p[len]; 2336 p[len] = '\0'; 2337 obj = load_object(p, -1, NULL, 0); 2338 if (obj == NULL) 2339 return -1; /* XXX - cleanup */ 2340 obj->z_interpose = true; 2341 p[len] = savech; 2342 p += len; 2343 p += strspn(p, delim); 2344 } 2345 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2346 return 0; 2347 } 2348 2349 static const char * 2350 printable_path(const char *path) 2351 { 2352 2353 return (path == NULL ? "<unknown>" : path); 2354 } 2355 2356 /* 2357 * Load a shared object into memory, if it is not already loaded. The 2358 * object may be specified by name or by user-supplied file descriptor 2359 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2360 * duplicate is. 2361 * 2362 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2363 * on failure. 2364 */ 2365 static Obj_Entry * 2366 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2367 { 2368 Obj_Entry *obj; 2369 int fd; 2370 struct stat sb; 2371 char *path; 2372 2373 fd = -1; 2374 if (name != NULL) { 2375 TAILQ_FOREACH(obj, &obj_list, next) { 2376 if (obj->marker || obj->doomed) 2377 continue; 2378 if (object_match_name(obj, name)) 2379 return (obj); 2380 } 2381 2382 path = find_library(name, refobj, &fd); 2383 if (path == NULL) 2384 return (NULL); 2385 } else 2386 path = NULL; 2387 2388 if (fd >= 0) { 2389 /* 2390 * search_library_pathfds() opens a fresh file descriptor for the 2391 * library, so there is no need to dup(). 2392 */ 2393 } else if (fd_u == -1) { 2394 /* 2395 * If we didn't find a match by pathname, or the name is not 2396 * supplied, open the file and check again by device and inode. 2397 * This avoids false mismatches caused by multiple links or ".." 2398 * in pathnames. 2399 * 2400 * To avoid a race, we open the file and use fstat() rather than 2401 * using stat(). 2402 */ 2403 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2404 _rtld_error("Cannot open \"%s\"", path); 2405 free(path); 2406 return (NULL); 2407 } 2408 } else { 2409 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2410 if (fd == -1) { 2411 _rtld_error("Cannot dup fd"); 2412 free(path); 2413 return (NULL); 2414 } 2415 } 2416 if (fstat(fd, &sb) == -1) { 2417 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2418 close(fd); 2419 free(path); 2420 return NULL; 2421 } 2422 TAILQ_FOREACH(obj, &obj_list, next) { 2423 if (obj->marker || obj->doomed) 2424 continue; 2425 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2426 break; 2427 } 2428 if (obj != NULL && name != NULL) { 2429 object_add_name(obj, name); 2430 free(path); 2431 close(fd); 2432 return obj; 2433 } 2434 if (flags & RTLD_LO_NOLOAD) { 2435 free(path); 2436 close(fd); 2437 return (NULL); 2438 } 2439 2440 /* First use of this object, so we must map it in */ 2441 obj = do_load_object(fd, name, path, &sb, flags); 2442 if (obj == NULL) 2443 free(path); 2444 close(fd); 2445 2446 return obj; 2447 } 2448 2449 static Obj_Entry * 2450 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2451 int flags) 2452 { 2453 Obj_Entry *obj; 2454 struct statfs fs; 2455 2456 /* 2457 * but first, make sure that environment variables haven't been 2458 * used to circumvent the noexec flag on a filesystem. 2459 */ 2460 if (dangerous_ld_env) { 2461 if (fstatfs(fd, &fs) != 0) { 2462 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2463 return NULL; 2464 } 2465 if (fs.f_flags & MNT_NOEXEC) { 2466 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2467 return NULL; 2468 } 2469 } 2470 dbg("loading \"%s\"", printable_path(path)); 2471 obj = map_object(fd, printable_path(path), sbp); 2472 if (obj == NULL) 2473 return NULL; 2474 2475 /* 2476 * If DT_SONAME is present in the object, digest_dynamic2 already 2477 * added it to the object names. 2478 */ 2479 if (name != NULL) 2480 object_add_name(obj, name); 2481 obj->path = path; 2482 digest_dynamic(obj, 0); 2483 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2484 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2485 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2486 RTLD_LO_DLOPEN) { 2487 dbg("refusing to load non-loadable \"%s\"", obj->path); 2488 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2489 munmap(obj->mapbase, obj->mapsize); 2490 obj_free(obj); 2491 return (NULL); 2492 } 2493 2494 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2495 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2496 obj_count++; 2497 obj_loads++; 2498 linkmap_add(obj); /* for GDB & dlinfo() */ 2499 max_stack_flags |= obj->stack_flags; 2500 2501 dbg(" %p .. %p: %s", obj->mapbase, 2502 obj->mapbase + obj->mapsize - 1, obj->path); 2503 if (obj->textrel) 2504 dbg(" WARNING: %s has impure text", obj->path); 2505 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2506 obj->path); 2507 2508 return obj; 2509 } 2510 2511 static Obj_Entry * 2512 obj_from_addr(const void *addr) 2513 { 2514 Obj_Entry *obj; 2515 2516 TAILQ_FOREACH(obj, &obj_list, next) { 2517 if (obj->marker) 2518 continue; 2519 if (addr < (void *) obj->mapbase) 2520 continue; 2521 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2522 return obj; 2523 } 2524 return NULL; 2525 } 2526 2527 static void 2528 preinit_main(void) 2529 { 2530 Elf_Addr *preinit_addr; 2531 int index; 2532 2533 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2534 if (preinit_addr == NULL) 2535 return; 2536 2537 for (index = 0; index < obj_main->preinit_array_num; index++) { 2538 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2539 dbg("calling preinit function for %s at %p", obj_main->path, 2540 (void *)preinit_addr[index]); 2541 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2542 0, 0, obj_main->path); 2543 call_init_pointer(obj_main, preinit_addr[index]); 2544 } 2545 } 2546 } 2547 2548 /* 2549 * Call the finalization functions for each of the objects in "list" 2550 * belonging to the DAG of "root" and referenced once. If NULL "root" 2551 * is specified, every finalization function will be called regardless 2552 * of the reference count and the list elements won't be freed. All of 2553 * the objects are expected to have non-NULL fini functions. 2554 */ 2555 static void 2556 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2557 { 2558 Objlist_Entry *elm; 2559 char *saved_msg; 2560 Elf_Addr *fini_addr; 2561 int index; 2562 2563 assert(root == NULL || root->refcount == 1); 2564 2565 if (root != NULL) 2566 root->doomed = true; 2567 2568 /* 2569 * Preserve the current error message since a fini function might 2570 * call into the dynamic linker and overwrite it. 2571 */ 2572 saved_msg = errmsg_save(); 2573 do { 2574 STAILQ_FOREACH(elm, list, link) { 2575 if (root != NULL && (elm->obj->refcount != 1 || 2576 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2577 continue; 2578 /* Remove object from fini list to prevent recursive invocation. */ 2579 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2580 /* Ensure that new references cannot be acquired. */ 2581 elm->obj->doomed = true; 2582 2583 hold_object(elm->obj); 2584 lock_release(rtld_bind_lock, lockstate); 2585 /* 2586 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2587 * When this happens, DT_FINI_ARRAY is processed first. 2588 */ 2589 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2590 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2591 for (index = elm->obj->fini_array_num - 1; index >= 0; 2592 index--) { 2593 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2594 dbg("calling fini function for %s at %p", 2595 elm->obj->path, (void *)fini_addr[index]); 2596 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2597 (void *)fini_addr[index], 0, 0, elm->obj->path); 2598 call_initfini_pointer(elm->obj, fini_addr[index]); 2599 } 2600 } 2601 } 2602 if (elm->obj->fini != (Elf_Addr)NULL) { 2603 dbg("calling fini function for %s at %p", elm->obj->path, 2604 (void *)elm->obj->fini); 2605 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2606 0, 0, elm->obj->path); 2607 call_initfini_pointer(elm->obj, elm->obj->fini); 2608 } 2609 wlock_acquire(rtld_bind_lock, lockstate); 2610 unhold_object(elm->obj); 2611 /* No need to free anything if process is going down. */ 2612 if (root != NULL) 2613 free(elm); 2614 /* 2615 * We must restart the list traversal after every fini call 2616 * because a dlclose() call from the fini function or from 2617 * another thread might have modified the reference counts. 2618 */ 2619 break; 2620 } 2621 } while (elm != NULL); 2622 errmsg_restore(saved_msg); 2623 } 2624 2625 /* 2626 * Call the initialization functions for each of the objects in 2627 * "list". All of the objects are expected to have non-NULL init 2628 * functions. 2629 */ 2630 static void 2631 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2632 { 2633 Objlist_Entry *elm; 2634 Obj_Entry *obj; 2635 char *saved_msg; 2636 Elf_Addr *init_addr; 2637 int index; 2638 2639 /* 2640 * Clean init_scanned flag so that objects can be rechecked and 2641 * possibly initialized earlier if any of vectors called below 2642 * cause the change by using dlopen. 2643 */ 2644 TAILQ_FOREACH(obj, &obj_list, next) { 2645 if (obj->marker) 2646 continue; 2647 obj->init_scanned = false; 2648 } 2649 2650 /* 2651 * Preserve the current error message since an init function might 2652 * call into the dynamic linker and overwrite it. 2653 */ 2654 saved_msg = errmsg_save(); 2655 STAILQ_FOREACH(elm, list, link) { 2656 if (elm->obj->init_done) /* Initialized early. */ 2657 continue; 2658 /* 2659 * Race: other thread might try to use this object before current 2660 * one completes the initialization. Not much can be done here 2661 * without better locking. 2662 */ 2663 elm->obj->init_done = true; 2664 hold_object(elm->obj); 2665 lock_release(rtld_bind_lock, lockstate); 2666 2667 /* 2668 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2669 * When this happens, DT_INIT is processed first. 2670 */ 2671 if (elm->obj->init != (Elf_Addr)NULL) { 2672 dbg("calling init function for %s at %p", elm->obj->path, 2673 (void *)elm->obj->init); 2674 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2675 0, 0, elm->obj->path); 2676 call_initfini_pointer(elm->obj, elm->obj->init); 2677 } 2678 init_addr = (Elf_Addr *)elm->obj->init_array; 2679 if (init_addr != NULL) { 2680 for (index = 0; index < elm->obj->init_array_num; index++) { 2681 if (init_addr[index] != 0 && init_addr[index] != 1) { 2682 dbg("calling init function for %s at %p", elm->obj->path, 2683 (void *)init_addr[index]); 2684 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2685 (void *)init_addr[index], 0, 0, elm->obj->path); 2686 call_init_pointer(elm->obj, init_addr[index]); 2687 } 2688 } 2689 } 2690 wlock_acquire(rtld_bind_lock, lockstate); 2691 unhold_object(elm->obj); 2692 } 2693 errmsg_restore(saved_msg); 2694 } 2695 2696 static void 2697 objlist_clear(Objlist *list) 2698 { 2699 Objlist_Entry *elm; 2700 2701 while (!STAILQ_EMPTY(list)) { 2702 elm = STAILQ_FIRST(list); 2703 STAILQ_REMOVE_HEAD(list, link); 2704 free(elm); 2705 } 2706 } 2707 2708 static Objlist_Entry * 2709 objlist_find(Objlist *list, const Obj_Entry *obj) 2710 { 2711 Objlist_Entry *elm; 2712 2713 STAILQ_FOREACH(elm, list, link) 2714 if (elm->obj == obj) 2715 return elm; 2716 return NULL; 2717 } 2718 2719 static void 2720 objlist_init(Objlist *list) 2721 { 2722 STAILQ_INIT(list); 2723 } 2724 2725 static void 2726 objlist_push_head(Objlist *list, Obj_Entry *obj) 2727 { 2728 Objlist_Entry *elm; 2729 2730 elm = NEW(Objlist_Entry); 2731 elm->obj = obj; 2732 STAILQ_INSERT_HEAD(list, elm, link); 2733 } 2734 2735 static void 2736 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2737 { 2738 Objlist_Entry *elm; 2739 2740 elm = NEW(Objlist_Entry); 2741 elm->obj = obj; 2742 STAILQ_INSERT_TAIL(list, elm, link); 2743 } 2744 2745 static void 2746 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2747 { 2748 Objlist_Entry *elm, *listelm; 2749 2750 STAILQ_FOREACH(listelm, list, link) { 2751 if (listelm->obj == listobj) 2752 break; 2753 } 2754 elm = NEW(Objlist_Entry); 2755 elm->obj = obj; 2756 if (listelm != NULL) 2757 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2758 else 2759 STAILQ_INSERT_TAIL(list, elm, link); 2760 } 2761 2762 static void 2763 objlist_remove(Objlist *list, Obj_Entry *obj) 2764 { 2765 Objlist_Entry *elm; 2766 2767 if ((elm = objlist_find(list, obj)) != NULL) { 2768 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2769 free(elm); 2770 } 2771 } 2772 2773 /* 2774 * Relocate dag rooted in the specified object. 2775 * Returns 0 on success, or -1 on failure. 2776 */ 2777 2778 static int 2779 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2780 int flags, RtldLockState *lockstate) 2781 { 2782 Objlist_Entry *elm; 2783 int error; 2784 2785 error = 0; 2786 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2787 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2788 lockstate); 2789 if (error == -1) 2790 break; 2791 } 2792 return (error); 2793 } 2794 2795 /* 2796 * Prepare for, or clean after, relocating an object marked with 2797 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2798 * segments are remapped read-write. After relocations are done, the 2799 * segment's permissions are returned back to the modes specified in 2800 * the phdrs. If any relocation happened, or always for wired 2801 * program, COW is triggered. 2802 */ 2803 static int 2804 reloc_textrel_prot(Obj_Entry *obj, bool before) 2805 { 2806 const Elf_Phdr *ph; 2807 void *base; 2808 size_t l, sz; 2809 int prot; 2810 2811 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2812 l--, ph++) { 2813 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2814 continue; 2815 base = obj->relocbase + trunc_page(ph->p_vaddr); 2816 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2817 trunc_page(ph->p_vaddr); 2818 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2819 if (mprotect(base, sz, prot) == -1) { 2820 _rtld_error("%s: Cannot write-%sable text segment: %s", 2821 obj->path, before ? "en" : "dis", 2822 rtld_strerror(errno)); 2823 return (-1); 2824 } 2825 } 2826 return (0); 2827 } 2828 2829 /* 2830 * Relocate single object. 2831 * Returns 0 on success, or -1 on failure. 2832 */ 2833 static int 2834 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2835 int flags, RtldLockState *lockstate) 2836 { 2837 2838 if (obj->relocated) 2839 return (0); 2840 obj->relocated = true; 2841 if (obj != rtldobj) 2842 dbg("relocating \"%s\"", obj->path); 2843 2844 if (obj->symtab == NULL || obj->strtab == NULL || 2845 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2846 _rtld_error("%s: Shared object has no run-time symbol table", 2847 obj->path); 2848 return (-1); 2849 } 2850 2851 /* There are relocations to the write-protected text segment. */ 2852 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2853 return (-1); 2854 2855 /* Process the non-PLT non-IFUNC relocations. */ 2856 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2857 return (-1); 2858 2859 /* Re-protected the text segment. */ 2860 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2861 return (-1); 2862 2863 /* Set the special PLT or GOT entries. */ 2864 init_pltgot(obj); 2865 2866 /* Process the PLT relocations. */ 2867 if (reloc_plt(obj, flags, lockstate) == -1) 2868 return (-1); 2869 /* Relocate the jump slots if we are doing immediate binding. */ 2870 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2871 lockstate) == -1) 2872 return (-1); 2873 2874 /* 2875 * Process the non-PLT IFUNC relocations. The relocations are 2876 * processed in two phases, because IFUNC resolvers may 2877 * reference other symbols, which must be readily processed 2878 * before resolvers are called. 2879 */ 2880 if (obj->non_plt_gnu_ifunc && 2881 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2882 return (-1); 2883 2884 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2885 return (-1); 2886 2887 /* 2888 * Set up the magic number and version in the Obj_Entry. These 2889 * were checked in the crt1.o from the original ElfKit, so we 2890 * set them for backward compatibility. 2891 */ 2892 obj->magic = RTLD_MAGIC; 2893 obj->version = RTLD_VERSION; 2894 2895 return (0); 2896 } 2897 2898 /* 2899 * Relocate newly-loaded shared objects. The argument is a pointer to 2900 * the Obj_Entry for the first such object. All objects from the first 2901 * to the end of the list of objects are relocated. Returns 0 on success, 2902 * or -1 on failure. 2903 */ 2904 static int 2905 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2906 int flags, RtldLockState *lockstate) 2907 { 2908 Obj_Entry *obj; 2909 int error; 2910 2911 for (error = 0, obj = first; obj != NULL; 2912 obj = TAILQ_NEXT(obj, next)) { 2913 if (obj->marker) 2914 continue; 2915 error = relocate_object(obj, bind_now, rtldobj, flags, 2916 lockstate); 2917 if (error == -1) 2918 break; 2919 } 2920 return (error); 2921 } 2922 2923 /* 2924 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2925 * referencing STT_GNU_IFUNC symbols is postponed till the other 2926 * relocations are done. The indirect functions specified as 2927 * ifunc are allowed to call other symbols, so we need to have 2928 * objects relocated before asking for resolution from indirects. 2929 * 2930 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2931 * instead of the usual lazy handling of PLT slots. It is 2932 * consistent with how GNU does it. 2933 */ 2934 static int 2935 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2936 RtldLockState *lockstate) 2937 { 2938 2939 if (obj->ifuncs_resolved) 2940 return (0); 2941 obj->ifuncs_resolved = true; 2942 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2943 return (-1); 2944 if ((obj->bind_now || bind_now) && obj->gnu_ifunc) { 2945 if (obj_disable_relro(obj) || 2946 reloc_gnu_ifunc(obj, flags, lockstate) == -1 || 2947 obj_enforce_relro(obj)) 2948 return (-1); 2949 } 2950 return (0); 2951 } 2952 2953 static int 2954 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2955 RtldLockState *lockstate) 2956 { 2957 Objlist_Entry *elm; 2958 Obj_Entry *obj; 2959 2960 STAILQ_FOREACH(elm, list, link) { 2961 obj = elm->obj; 2962 if (obj->marker) 2963 continue; 2964 if (resolve_object_ifunc(obj, bind_now, flags, 2965 lockstate) == -1) 2966 return (-1); 2967 } 2968 return (0); 2969 } 2970 2971 /* 2972 * Cleanup procedure. It will be called (by the atexit mechanism) just 2973 * before the process exits. 2974 */ 2975 static void 2976 rtld_exit(void) 2977 { 2978 RtldLockState lockstate; 2979 2980 wlock_acquire(rtld_bind_lock, &lockstate); 2981 dbg("rtld_exit()"); 2982 objlist_call_fini(&list_fini, NULL, &lockstate); 2983 /* No need to remove the items from the list, since we are exiting. */ 2984 if (!libmap_disable) 2985 lm_fini(); 2986 lock_release(rtld_bind_lock, &lockstate); 2987 } 2988 2989 /* 2990 * Iterate over a search path, translate each element, and invoke the 2991 * callback on the result. 2992 */ 2993 static void * 2994 path_enumerate(const char *path, path_enum_proc callback, 2995 const char *refobj_path, void *arg) 2996 { 2997 const char *trans; 2998 if (path == NULL) 2999 return (NULL); 3000 3001 path += strspn(path, ":;"); 3002 while (*path != '\0') { 3003 size_t len; 3004 char *res; 3005 3006 len = strcspn(path, ":;"); 3007 trans = lm_findn(refobj_path, path, len); 3008 if (trans) 3009 res = callback(trans, strlen(trans), arg); 3010 else 3011 res = callback(path, len, arg); 3012 3013 if (res != NULL) 3014 return (res); 3015 3016 path += len; 3017 path += strspn(path, ":;"); 3018 } 3019 3020 return (NULL); 3021 } 3022 3023 struct try_library_args { 3024 const char *name; 3025 size_t namelen; 3026 char *buffer; 3027 size_t buflen; 3028 int fd; 3029 }; 3030 3031 static void * 3032 try_library_path(const char *dir, size_t dirlen, void *param) 3033 { 3034 struct try_library_args *arg; 3035 int fd; 3036 3037 arg = param; 3038 if (*dir == '/' || trust) { 3039 char *pathname; 3040 3041 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3042 return (NULL); 3043 3044 pathname = arg->buffer; 3045 strncpy(pathname, dir, dirlen); 3046 pathname[dirlen] = '/'; 3047 strcpy(pathname + dirlen + 1, arg->name); 3048 3049 dbg(" Trying \"%s\"", pathname); 3050 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3051 if (fd >= 0) { 3052 dbg(" Opened \"%s\", fd %d", pathname, fd); 3053 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3054 strcpy(pathname, arg->buffer); 3055 arg->fd = fd; 3056 return (pathname); 3057 } else { 3058 dbg(" Failed to open \"%s\": %s", 3059 pathname, rtld_strerror(errno)); 3060 } 3061 } 3062 return (NULL); 3063 } 3064 3065 static char * 3066 search_library_path(const char *name, const char *path, 3067 const char *refobj_path, int *fdp) 3068 { 3069 char *p; 3070 struct try_library_args arg; 3071 3072 if (path == NULL) 3073 return NULL; 3074 3075 arg.name = name; 3076 arg.namelen = strlen(name); 3077 arg.buffer = xmalloc(PATH_MAX); 3078 arg.buflen = PATH_MAX; 3079 arg.fd = -1; 3080 3081 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3082 *fdp = arg.fd; 3083 3084 free(arg.buffer); 3085 3086 return (p); 3087 } 3088 3089 3090 /* 3091 * Finds the library with the given name using the directory descriptors 3092 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3093 * 3094 * Returns a freshly-opened close-on-exec file descriptor for the library, 3095 * or -1 if the library cannot be found. 3096 */ 3097 static char * 3098 search_library_pathfds(const char *name, const char *path, int *fdp) 3099 { 3100 char *envcopy, *fdstr, *found, *last_token; 3101 size_t len; 3102 int dirfd, fd; 3103 3104 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3105 3106 /* Don't load from user-specified libdirs into setuid binaries. */ 3107 if (!trust) 3108 return (NULL); 3109 3110 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3111 if (path == NULL) 3112 return (NULL); 3113 3114 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3115 if (name[0] == '/') { 3116 dbg("Absolute path (%s) passed to %s", name, __func__); 3117 return (NULL); 3118 } 3119 3120 /* 3121 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3122 * copy of the path, as strtok_r rewrites separator tokens 3123 * with '\0'. 3124 */ 3125 found = NULL; 3126 envcopy = xstrdup(path); 3127 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3128 fdstr = strtok_r(NULL, ":", &last_token)) { 3129 dirfd = parse_integer(fdstr); 3130 if (dirfd < 0) { 3131 _rtld_error("failed to parse directory FD: '%s'", 3132 fdstr); 3133 break; 3134 } 3135 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3136 if (fd >= 0) { 3137 *fdp = fd; 3138 len = strlen(fdstr) + strlen(name) + 3; 3139 found = xmalloc(len); 3140 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3141 _rtld_error("error generating '%d/%s'", 3142 dirfd, name); 3143 rtld_die(); 3144 } 3145 dbg("open('%s') => %d", found, fd); 3146 break; 3147 } 3148 } 3149 free(envcopy); 3150 3151 return (found); 3152 } 3153 3154 3155 int 3156 dlclose(void *handle) 3157 { 3158 RtldLockState lockstate; 3159 int error; 3160 3161 wlock_acquire(rtld_bind_lock, &lockstate); 3162 error = dlclose_locked(handle, &lockstate); 3163 lock_release(rtld_bind_lock, &lockstate); 3164 return (error); 3165 } 3166 3167 static int 3168 dlclose_locked(void *handle, RtldLockState *lockstate) 3169 { 3170 Obj_Entry *root; 3171 3172 root = dlcheck(handle); 3173 if (root == NULL) 3174 return -1; 3175 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3176 root->path); 3177 3178 /* Unreference the object and its dependencies. */ 3179 root->dl_refcount--; 3180 3181 if (root->refcount == 1) { 3182 /* 3183 * The object will be no longer referenced, so we must unload it. 3184 * First, call the fini functions. 3185 */ 3186 objlist_call_fini(&list_fini, root, lockstate); 3187 3188 unref_dag(root); 3189 3190 /* Finish cleaning up the newly-unreferenced objects. */ 3191 GDB_STATE(RT_DELETE,&root->linkmap); 3192 unload_object(root, lockstate); 3193 GDB_STATE(RT_CONSISTENT,NULL); 3194 } else 3195 unref_dag(root); 3196 3197 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3198 return 0; 3199 } 3200 3201 char * 3202 dlerror(void) 3203 { 3204 char *msg = error_message; 3205 error_message = NULL; 3206 return msg; 3207 } 3208 3209 /* 3210 * This function is deprecated and has no effect. 3211 */ 3212 void 3213 dllockinit(void *context, 3214 void *(*lock_create)(void *context), 3215 void (*rlock_acquire)(void *lock), 3216 void (*wlock_acquire)(void *lock), 3217 void (*lock_release)(void *lock), 3218 void (*lock_destroy)(void *lock), 3219 void (*context_destroy)(void *context)) 3220 { 3221 static void *cur_context; 3222 static void (*cur_context_destroy)(void *); 3223 3224 /* Just destroy the context from the previous call, if necessary. */ 3225 if (cur_context_destroy != NULL) 3226 cur_context_destroy(cur_context); 3227 cur_context = context; 3228 cur_context_destroy = context_destroy; 3229 } 3230 3231 void * 3232 dlopen(const char *name, int mode) 3233 { 3234 3235 return (rtld_dlopen(name, -1, mode)); 3236 } 3237 3238 void * 3239 fdlopen(int fd, int mode) 3240 { 3241 3242 return (rtld_dlopen(NULL, fd, mode)); 3243 } 3244 3245 static void * 3246 rtld_dlopen(const char *name, int fd, int mode) 3247 { 3248 RtldLockState lockstate; 3249 int lo_flags; 3250 3251 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3252 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3253 if (ld_tracing != NULL) { 3254 rlock_acquire(rtld_bind_lock, &lockstate); 3255 if (sigsetjmp(lockstate.env, 0) != 0) 3256 lock_upgrade(rtld_bind_lock, &lockstate); 3257 environ = (char **)*get_program_var_addr("environ", &lockstate); 3258 lock_release(rtld_bind_lock, &lockstate); 3259 } 3260 lo_flags = RTLD_LO_DLOPEN; 3261 if (mode & RTLD_NODELETE) 3262 lo_flags |= RTLD_LO_NODELETE; 3263 if (mode & RTLD_NOLOAD) 3264 lo_flags |= RTLD_LO_NOLOAD; 3265 if (ld_tracing != NULL) 3266 lo_flags |= RTLD_LO_TRACE; 3267 3268 return (dlopen_object(name, fd, obj_main, lo_flags, 3269 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3270 } 3271 3272 static void 3273 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3274 { 3275 3276 obj->dl_refcount--; 3277 unref_dag(obj); 3278 if (obj->refcount == 0) 3279 unload_object(obj, lockstate); 3280 } 3281 3282 static Obj_Entry * 3283 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3284 int mode, RtldLockState *lockstate) 3285 { 3286 Obj_Entry *old_obj_tail; 3287 Obj_Entry *obj; 3288 Objlist initlist; 3289 RtldLockState mlockstate; 3290 int result; 3291 3292 objlist_init(&initlist); 3293 3294 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3295 wlock_acquire(rtld_bind_lock, &mlockstate); 3296 lockstate = &mlockstate; 3297 } 3298 GDB_STATE(RT_ADD,NULL); 3299 3300 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3301 obj = NULL; 3302 if (name == NULL && fd == -1) { 3303 obj = obj_main; 3304 obj->refcount++; 3305 } else { 3306 obj = load_object(name, fd, refobj, lo_flags); 3307 } 3308 3309 if (obj) { 3310 obj->dl_refcount++; 3311 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3312 objlist_push_tail(&list_global, obj); 3313 if (globallist_next(old_obj_tail) != NULL) { 3314 /* We loaded something new. */ 3315 assert(globallist_next(old_obj_tail) == obj); 3316 result = load_needed_objects(obj, 3317 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3318 init_dag(obj); 3319 ref_dag(obj); 3320 if (result != -1) 3321 result = rtld_verify_versions(&obj->dagmembers); 3322 if (result != -1 && ld_tracing) 3323 goto trace; 3324 if (result == -1 || relocate_object_dag(obj, 3325 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3326 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3327 lockstate) == -1) { 3328 dlopen_cleanup(obj, lockstate); 3329 obj = NULL; 3330 } else if (lo_flags & RTLD_LO_EARLY) { 3331 /* 3332 * Do not call the init functions for early loaded 3333 * filtees. The image is still not initialized enough 3334 * for them to work. 3335 * 3336 * Our object is found by the global object list and 3337 * will be ordered among all init calls done right 3338 * before transferring control to main. 3339 */ 3340 } else { 3341 /* Make list of init functions to call. */ 3342 initlist_add_objects(obj, obj, &initlist); 3343 } 3344 /* 3345 * Process all no_delete or global objects here, given 3346 * them own DAGs to prevent their dependencies from being 3347 * unloaded. This has to be done after we have loaded all 3348 * of the dependencies, so that we do not miss any. 3349 */ 3350 if (obj != NULL) 3351 process_z(obj); 3352 } else { 3353 /* 3354 * Bump the reference counts for objects on this DAG. If 3355 * this is the first dlopen() call for the object that was 3356 * already loaded as a dependency, initialize the dag 3357 * starting at it. 3358 */ 3359 init_dag(obj); 3360 ref_dag(obj); 3361 3362 if ((lo_flags & RTLD_LO_TRACE) != 0) 3363 goto trace; 3364 } 3365 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3366 obj->z_nodelete) && !obj->ref_nodel) { 3367 dbg("obj %s nodelete", obj->path); 3368 ref_dag(obj); 3369 obj->z_nodelete = obj->ref_nodel = true; 3370 } 3371 } 3372 3373 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3374 name); 3375 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3376 3377 if (!(lo_flags & RTLD_LO_EARLY)) { 3378 map_stacks_exec(lockstate); 3379 } 3380 3381 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3382 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3383 lockstate) == -1) { 3384 objlist_clear(&initlist); 3385 dlopen_cleanup(obj, lockstate); 3386 if (lockstate == &mlockstate) 3387 lock_release(rtld_bind_lock, lockstate); 3388 return (NULL); 3389 } 3390 3391 if (!(lo_flags & RTLD_LO_EARLY)) { 3392 /* Call the init functions. */ 3393 objlist_call_init(&initlist, lockstate); 3394 } 3395 objlist_clear(&initlist); 3396 if (lockstate == &mlockstate) 3397 lock_release(rtld_bind_lock, lockstate); 3398 return obj; 3399 trace: 3400 trace_loaded_objects(obj); 3401 if (lockstate == &mlockstate) 3402 lock_release(rtld_bind_lock, lockstate); 3403 exit(0); 3404 } 3405 3406 static void * 3407 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3408 int flags) 3409 { 3410 DoneList donelist; 3411 const Obj_Entry *obj, *defobj; 3412 const Elf_Sym *def; 3413 SymLook req; 3414 RtldLockState lockstate; 3415 tls_index ti; 3416 void *sym; 3417 int res; 3418 3419 def = NULL; 3420 defobj = NULL; 3421 symlook_init(&req, name); 3422 req.ventry = ve; 3423 req.flags = flags | SYMLOOK_IN_PLT; 3424 req.lockstate = &lockstate; 3425 3426 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3427 rlock_acquire(rtld_bind_lock, &lockstate); 3428 if (sigsetjmp(lockstate.env, 0) != 0) 3429 lock_upgrade(rtld_bind_lock, &lockstate); 3430 if (handle == NULL || handle == RTLD_NEXT || 3431 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3432 3433 if ((obj = obj_from_addr(retaddr)) == NULL) { 3434 _rtld_error("Cannot determine caller's shared object"); 3435 lock_release(rtld_bind_lock, &lockstate); 3436 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3437 return NULL; 3438 } 3439 if (handle == NULL) { /* Just the caller's shared object. */ 3440 res = symlook_obj(&req, obj); 3441 if (res == 0) { 3442 def = req.sym_out; 3443 defobj = req.defobj_out; 3444 } 3445 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3446 handle == RTLD_SELF) { /* ... caller included */ 3447 if (handle == RTLD_NEXT) 3448 obj = globallist_next(obj); 3449 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3450 if (obj->marker) 3451 continue; 3452 res = symlook_obj(&req, obj); 3453 if (res == 0) { 3454 if (def == NULL || 3455 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3456 def = req.sym_out; 3457 defobj = req.defobj_out; 3458 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3459 break; 3460 } 3461 } 3462 } 3463 /* 3464 * Search the dynamic linker itself, and possibly resolve the 3465 * symbol from there. This is how the application links to 3466 * dynamic linker services such as dlopen. 3467 */ 3468 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3469 res = symlook_obj(&req, &obj_rtld); 3470 if (res == 0) { 3471 def = req.sym_out; 3472 defobj = req.defobj_out; 3473 } 3474 } 3475 } else { 3476 assert(handle == RTLD_DEFAULT); 3477 res = symlook_default(&req, obj); 3478 if (res == 0) { 3479 defobj = req.defobj_out; 3480 def = req.sym_out; 3481 } 3482 } 3483 } else { 3484 if ((obj = dlcheck(handle)) == NULL) { 3485 lock_release(rtld_bind_lock, &lockstate); 3486 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3487 return NULL; 3488 } 3489 3490 donelist_init(&donelist); 3491 if (obj->mainprog) { 3492 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3493 res = symlook_global(&req, &donelist); 3494 if (res == 0) { 3495 def = req.sym_out; 3496 defobj = req.defobj_out; 3497 } 3498 /* 3499 * Search the dynamic linker itself, and possibly resolve the 3500 * symbol from there. This is how the application links to 3501 * dynamic linker services such as dlopen. 3502 */ 3503 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3504 res = symlook_obj(&req, &obj_rtld); 3505 if (res == 0) { 3506 def = req.sym_out; 3507 defobj = req.defobj_out; 3508 } 3509 } 3510 } 3511 else { 3512 /* Search the whole DAG rooted at the given object. */ 3513 res = symlook_list(&req, &obj->dagmembers, &donelist); 3514 if (res == 0) { 3515 def = req.sym_out; 3516 defobj = req.defobj_out; 3517 } 3518 } 3519 } 3520 3521 if (def != NULL) { 3522 lock_release(rtld_bind_lock, &lockstate); 3523 3524 /* 3525 * The value required by the caller is derived from the value 3526 * of the symbol. this is simply the relocated value of the 3527 * symbol. 3528 */ 3529 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3530 sym = make_function_pointer(def, defobj); 3531 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3532 sym = rtld_resolve_ifunc(defobj, def); 3533 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3534 ti.ti_module = defobj->tlsindex; 3535 ti.ti_offset = def->st_value; 3536 sym = __tls_get_addr(&ti); 3537 } else 3538 sym = defobj->relocbase + def->st_value; 3539 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3540 return (sym); 3541 } 3542 3543 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3544 ve != NULL ? ve->name : ""); 3545 lock_release(rtld_bind_lock, &lockstate); 3546 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3547 return NULL; 3548 } 3549 3550 void * 3551 dlsym(void *handle, const char *name) 3552 { 3553 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3554 SYMLOOK_DLSYM); 3555 } 3556 3557 dlfunc_t 3558 dlfunc(void *handle, const char *name) 3559 { 3560 union { 3561 void *d; 3562 dlfunc_t f; 3563 } rv; 3564 3565 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3566 SYMLOOK_DLSYM); 3567 return (rv.f); 3568 } 3569 3570 void * 3571 dlvsym(void *handle, const char *name, const char *version) 3572 { 3573 Ver_Entry ventry; 3574 3575 ventry.name = version; 3576 ventry.file = NULL; 3577 ventry.hash = elf_hash(version); 3578 ventry.flags= 0; 3579 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3580 SYMLOOK_DLSYM); 3581 } 3582 3583 int 3584 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3585 { 3586 const Obj_Entry *obj; 3587 RtldLockState lockstate; 3588 3589 rlock_acquire(rtld_bind_lock, &lockstate); 3590 obj = obj_from_addr(addr); 3591 if (obj == NULL) { 3592 _rtld_error("No shared object contains address"); 3593 lock_release(rtld_bind_lock, &lockstate); 3594 return (0); 3595 } 3596 rtld_fill_dl_phdr_info(obj, phdr_info); 3597 lock_release(rtld_bind_lock, &lockstate); 3598 return (1); 3599 } 3600 3601 int 3602 dladdr(const void *addr, Dl_info *info) 3603 { 3604 const Obj_Entry *obj; 3605 const Elf_Sym *def; 3606 void *symbol_addr; 3607 unsigned long symoffset; 3608 RtldLockState lockstate; 3609 3610 rlock_acquire(rtld_bind_lock, &lockstate); 3611 obj = obj_from_addr(addr); 3612 if (obj == NULL) { 3613 _rtld_error("No shared object contains address"); 3614 lock_release(rtld_bind_lock, &lockstate); 3615 return 0; 3616 } 3617 info->dli_fname = obj->path; 3618 info->dli_fbase = obj->mapbase; 3619 info->dli_saddr = (void *)0; 3620 info->dli_sname = NULL; 3621 3622 /* 3623 * Walk the symbol list looking for the symbol whose address is 3624 * closest to the address sent in. 3625 */ 3626 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3627 def = obj->symtab + symoffset; 3628 3629 /* 3630 * For skip the symbol if st_shndx is either SHN_UNDEF or 3631 * SHN_COMMON. 3632 */ 3633 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3634 continue; 3635 3636 /* 3637 * If the symbol is greater than the specified address, or if it 3638 * is further away from addr than the current nearest symbol, 3639 * then reject it. 3640 */ 3641 symbol_addr = obj->relocbase + def->st_value; 3642 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3643 continue; 3644 3645 /* Update our idea of the nearest symbol. */ 3646 info->dli_sname = obj->strtab + def->st_name; 3647 info->dli_saddr = symbol_addr; 3648 3649 /* Exact match? */ 3650 if (info->dli_saddr == addr) 3651 break; 3652 } 3653 lock_release(rtld_bind_lock, &lockstate); 3654 return 1; 3655 } 3656 3657 int 3658 dlinfo(void *handle, int request, void *p) 3659 { 3660 const Obj_Entry *obj; 3661 RtldLockState lockstate; 3662 int error; 3663 3664 rlock_acquire(rtld_bind_lock, &lockstate); 3665 3666 if (handle == NULL || handle == RTLD_SELF) { 3667 void *retaddr; 3668 3669 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3670 if ((obj = obj_from_addr(retaddr)) == NULL) 3671 _rtld_error("Cannot determine caller's shared object"); 3672 } else 3673 obj = dlcheck(handle); 3674 3675 if (obj == NULL) { 3676 lock_release(rtld_bind_lock, &lockstate); 3677 return (-1); 3678 } 3679 3680 error = 0; 3681 switch (request) { 3682 case RTLD_DI_LINKMAP: 3683 *((struct link_map const **)p) = &obj->linkmap; 3684 break; 3685 case RTLD_DI_ORIGIN: 3686 error = rtld_dirname(obj->path, p); 3687 break; 3688 3689 case RTLD_DI_SERINFOSIZE: 3690 case RTLD_DI_SERINFO: 3691 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3692 break; 3693 3694 default: 3695 _rtld_error("Invalid request %d passed to dlinfo()", request); 3696 error = -1; 3697 } 3698 3699 lock_release(rtld_bind_lock, &lockstate); 3700 3701 return (error); 3702 } 3703 3704 static void 3705 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3706 { 3707 3708 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3709 phdr_info->dlpi_name = obj->path; 3710 phdr_info->dlpi_phdr = obj->phdr; 3711 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3712 phdr_info->dlpi_tls_modid = obj->tlsindex; 3713 phdr_info->dlpi_tls_data = obj->tlsinit; 3714 phdr_info->dlpi_adds = obj_loads; 3715 phdr_info->dlpi_subs = obj_loads - obj_count; 3716 } 3717 3718 int 3719 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3720 { 3721 struct dl_phdr_info phdr_info; 3722 Obj_Entry *obj, marker; 3723 RtldLockState bind_lockstate, phdr_lockstate; 3724 int error; 3725 3726 init_marker(&marker); 3727 error = 0; 3728 3729 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3730 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3731 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3732 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3733 rtld_fill_dl_phdr_info(obj, &phdr_info); 3734 hold_object(obj); 3735 lock_release(rtld_bind_lock, &bind_lockstate); 3736 3737 error = callback(&phdr_info, sizeof phdr_info, param); 3738 3739 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3740 unhold_object(obj); 3741 obj = globallist_next(&marker); 3742 TAILQ_REMOVE(&obj_list, &marker, next); 3743 if (error != 0) { 3744 lock_release(rtld_bind_lock, &bind_lockstate); 3745 lock_release(rtld_phdr_lock, &phdr_lockstate); 3746 return (error); 3747 } 3748 } 3749 3750 if (error == 0) { 3751 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3752 lock_release(rtld_bind_lock, &bind_lockstate); 3753 error = callback(&phdr_info, sizeof(phdr_info), param); 3754 } 3755 lock_release(rtld_phdr_lock, &phdr_lockstate); 3756 return (error); 3757 } 3758 3759 static void * 3760 fill_search_info(const char *dir, size_t dirlen, void *param) 3761 { 3762 struct fill_search_info_args *arg; 3763 3764 arg = param; 3765 3766 if (arg->request == RTLD_DI_SERINFOSIZE) { 3767 arg->serinfo->dls_cnt ++; 3768 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3769 } else { 3770 struct dl_serpath *s_entry; 3771 3772 s_entry = arg->serpath; 3773 s_entry->dls_name = arg->strspace; 3774 s_entry->dls_flags = arg->flags; 3775 3776 strncpy(arg->strspace, dir, dirlen); 3777 arg->strspace[dirlen] = '\0'; 3778 3779 arg->strspace += dirlen + 1; 3780 arg->serpath++; 3781 } 3782 3783 return (NULL); 3784 } 3785 3786 static int 3787 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3788 { 3789 struct dl_serinfo _info; 3790 struct fill_search_info_args args; 3791 3792 args.request = RTLD_DI_SERINFOSIZE; 3793 args.serinfo = &_info; 3794 3795 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3796 _info.dls_cnt = 0; 3797 3798 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3799 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3800 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3801 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3802 if (!obj->z_nodeflib) 3803 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3804 3805 3806 if (request == RTLD_DI_SERINFOSIZE) { 3807 info->dls_size = _info.dls_size; 3808 info->dls_cnt = _info.dls_cnt; 3809 return (0); 3810 } 3811 3812 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3813 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3814 return (-1); 3815 } 3816 3817 args.request = RTLD_DI_SERINFO; 3818 args.serinfo = info; 3819 args.serpath = &info->dls_serpath[0]; 3820 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3821 3822 args.flags = LA_SER_RUNPATH; 3823 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3824 return (-1); 3825 3826 args.flags = LA_SER_LIBPATH; 3827 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3828 return (-1); 3829 3830 args.flags = LA_SER_RUNPATH; 3831 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3832 return (-1); 3833 3834 args.flags = LA_SER_CONFIG; 3835 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3836 != NULL) 3837 return (-1); 3838 3839 args.flags = LA_SER_DEFAULT; 3840 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3841 fill_search_info, NULL, &args) != NULL) 3842 return (-1); 3843 return (0); 3844 } 3845 3846 static int 3847 rtld_dirname(const char *path, char *bname) 3848 { 3849 const char *endp; 3850 3851 /* Empty or NULL string gets treated as "." */ 3852 if (path == NULL || *path == '\0') { 3853 bname[0] = '.'; 3854 bname[1] = '\0'; 3855 return (0); 3856 } 3857 3858 /* Strip trailing slashes */ 3859 endp = path + strlen(path) - 1; 3860 while (endp > path && *endp == '/') 3861 endp--; 3862 3863 /* Find the start of the dir */ 3864 while (endp > path && *endp != '/') 3865 endp--; 3866 3867 /* Either the dir is "/" or there are no slashes */ 3868 if (endp == path) { 3869 bname[0] = *endp == '/' ? '/' : '.'; 3870 bname[1] = '\0'; 3871 return (0); 3872 } else { 3873 do { 3874 endp--; 3875 } while (endp > path && *endp == '/'); 3876 } 3877 3878 if (endp - path + 2 > PATH_MAX) 3879 { 3880 _rtld_error("Filename is too long: %s", path); 3881 return(-1); 3882 } 3883 3884 strncpy(bname, path, endp - path + 1); 3885 bname[endp - path + 1] = '\0'; 3886 return (0); 3887 } 3888 3889 static int 3890 rtld_dirname_abs(const char *path, char *base) 3891 { 3892 char *last; 3893 3894 if (realpath(path, base) == NULL) 3895 return (-1); 3896 dbg("%s -> %s", path, base); 3897 last = strrchr(base, '/'); 3898 if (last == NULL) 3899 return (-1); 3900 if (last != base) 3901 *last = '\0'; 3902 return (0); 3903 } 3904 3905 static void 3906 linkmap_add(Obj_Entry *obj) 3907 { 3908 struct link_map *l = &obj->linkmap; 3909 struct link_map *prev; 3910 3911 obj->linkmap.l_name = obj->path; 3912 obj->linkmap.l_addr = obj->mapbase; 3913 obj->linkmap.l_ld = obj->dynamic; 3914 #ifdef __mips__ 3915 /* GDB needs load offset on MIPS to use the symbols */ 3916 obj->linkmap.l_offs = obj->relocbase; 3917 #endif 3918 3919 if (r_debug.r_map == NULL) { 3920 r_debug.r_map = l; 3921 return; 3922 } 3923 3924 /* 3925 * Scan to the end of the list, but not past the entry for the 3926 * dynamic linker, which we want to keep at the very end. 3927 */ 3928 for (prev = r_debug.r_map; 3929 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3930 prev = prev->l_next) 3931 ; 3932 3933 /* Link in the new entry. */ 3934 l->l_prev = prev; 3935 l->l_next = prev->l_next; 3936 if (l->l_next != NULL) 3937 l->l_next->l_prev = l; 3938 prev->l_next = l; 3939 } 3940 3941 static void 3942 linkmap_delete(Obj_Entry *obj) 3943 { 3944 struct link_map *l = &obj->linkmap; 3945 3946 if (l->l_prev == NULL) { 3947 if ((r_debug.r_map = l->l_next) != NULL) 3948 l->l_next->l_prev = NULL; 3949 return; 3950 } 3951 3952 if ((l->l_prev->l_next = l->l_next) != NULL) 3953 l->l_next->l_prev = l->l_prev; 3954 } 3955 3956 /* 3957 * Function for the debugger to set a breakpoint on to gain control. 3958 * 3959 * The two parameters allow the debugger to easily find and determine 3960 * what the runtime loader is doing and to whom it is doing it. 3961 * 3962 * When the loadhook trap is hit (r_debug_state, set at program 3963 * initialization), the arguments can be found on the stack: 3964 * 3965 * +8 struct link_map *m 3966 * +4 struct r_debug *rd 3967 * +0 RetAddr 3968 */ 3969 void 3970 r_debug_state(struct r_debug* rd, struct link_map *m) 3971 { 3972 /* 3973 * The following is a hack to force the compiler to emit calls to 3974 * this function, even when optimizing. If the function is empty, 3975 * the compiler is not obliged to emit any code for calls to it, 3976 * even when marked __noinline. However, gdb depends on those 3977 * calls being made. 3978 */ 3979 __compiler_membar(); 3980 } 3981 3982 /* 3983 * A function called after init routines have completed. This can be used to 3984 * break before a program's entry routine is called, and can be used when 3985 * main is not available in the symbol table. 3986 */ 3987 void 3988 _r_debug_postinit(struct link_map *m) 3989 { 3990 3991 /* See r_debug_state(). */ 3992 __compiler_membar(); 3993 } 3994 3995 static void 3996 release_object(Obj_Entry *obj) 3997 { 3998 3999 if (obj->holdcount > 0) { 4000 obj->unholdfree = true; 4001 return; 4002 } 4003 munmap(obj->mapbase, obj->mapsize); 4004 linkmap_delete(obj); 4005 obj_free(obj); 4006 } 4007 4008 /* 4009 * Get address of the pointer variable in the main program. 4010 * Prefer non-weak symbol over the weak one. 4011 */ 4012 static const void ** 4013 get_program_var_addr(const char *name, RtldLockState *lockstate) 4014 { 4015 SymLook req; 4016 DoneList donelist; 4017 4018 symlook_init(&req, name); 4019 req.lockstate = lockstate; 4020 donelist_init(&donelist); 4021 if (symlook_global(&req, &donelist) != 0) 4022 return (NULL); 4023 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4024 return ((const void **)make_function_pointer(req.sym_out, 4025 req.defobj_out)); 4026 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4027 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4028 else 4029 return ((const void **)(req.defobj_out->relocbase + 4030 req.sym_out->st_value)); 4031 } 4032 4033 /* 4034 * Set a pointer variable in the main program to the given value. This 4035 * is used to set key variables such as "environ" before any of the 4036 * init functions are called. 4037 */ 4038 static void 4039 set_program_var(const char *name, const void *value) 4040 { 4041 const void **addr; 4042 4043 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4044 dbg("\"%s\": *%p <-- %p", name, addr, value); 4045 *addr = value; 4046 } 4047 } 4048 4049 /* 4050 * Search the global objects, including dependencies and main object, 4051 * for the given symbol. 4052 */ 4053 static int 4054 symlook_global(SymLook *req, DoneList *donelist) 4055 { 4056 SymLook req1; 4057 const Objlist_Entry *elm; 4058 int res; 4059 4060 symlook_init_from_req(&req1, req); 4061 4062 /* Search all objects loaded at program start up. */ 4063 if (req->defobj_out == NULL || 4064 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4065 res = symlook_list(&req1, &list_main, donelist); 4066 if (res == 0 && (req->defobj_out == NULL || 4067 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4068 req->sym_out = req1.sym_out; 4069 req->defobj_out = req1.defobj_out; 4070 assert(req->defobj_out != NULL); 4071 } 4072 } 4073 4074 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4075 STAILQ_FOREACH(elm, &list_global, link) { 4076 if (req->defobj_out != NULL && 4077 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4078 break; 4079 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4080 if (res == 0 && (req->defobj_out == NULL || 4081 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4082 req->sym_out = req1.sym_out; 4083 req->defobj_out = req1.defobj_out; 4084 assert(req->defobj_out != NULL); 4085 } 4086 } 4087 4088 return (req->sym_out != NULL ? 0 : ESRCH); 4089 } 4090 4091 /* 4092 * Given a symbol name in a referencing object, find the corresponding 4093 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4094 * no definition was found. Returns a pointer to the Obj_Entry of the 4095 * defining object via the reference parameter DEFOBJ_OUT. 4096 */ 4097 static int 4098 symlook_default(SymLook *req, const Obj_Entry *refobj) 4099 { 4100 DoneList donelist; 4101 const Objlist_Entry *elm; 4102 SymLook req1; 4103 int res; 4104 4105 donelist_init(&donelist); 4106 symlook_init_from_req(&req1, req); 4107 4108 /* 4109 * Look first in the referencing object if linked symbolically, 4110 * and similarly handle protected symbols. 4111 */ 4112 res = symlook_obj(&req1, refobj); 4113 if (res == 0 && (refobj->symbolic || 4114 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4115 req->sym_out = req1.sym_out; 4116 req->defobj_out = req1.defobj_out; 4117 assert(req->defobj_out != NULL); 4118 } 4119 if (refobj->symbolic || req->defobj_out != NULL) 4120 donelist_check(&donelist, refobj); 4121 4122 symlook_global(req, &donelist); 4123 4124 /* Search all dlopened DAGs containing the referencing object. */ 4125 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4126 if (req->sym_out != NULL && 4127 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4128 break; 4129 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4130 if (res == 0 && (req->sym_out == NULL || 4131 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4132 req->sym_out = req1.sym_out; 4133 req->defobj_out = req1.defobj_out; 4134 assert(req->defobj_out != NULL); 4135 } 4136 } 4137 4138 /* 4139 * Search the dynamic linker itself, and possibly resolve the 4140 * symbol from there. This is how the application links to 4141 * dynamic linker services such as dlopen. 4142 */ 4143 if (req->sym_out == NULL || 4144 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4145 res = symlook_obj(&req1, &obj_rtld); 4146 if (res == 0) { 4147 req->sym_out = req1.sym_out; 4148 req->defobj_out = req1.defobj_out; 4149 assert(req->defobj_out != NULL); 4150 } 4151 } 4152 4153 return (req->sym_out != NULL ? 0 : ESRCH); 4154 } 4155 4156 static int 4157 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4158 { 4159 const Elf_Sym *def; 4160 const Obj_Entry *defobj; 4161 const Objlist_Entry *elm; 4162 SymLook req1; 4163 int res; 4164 4165 def = NULL; 4166 defobj = NULL; 4167 STAILQ_FOREACH(elm, objlist, link) { 4168 if (donelist_check(dlp, elm->obj)) 4169 continue; 4170 symlook_init_from_req(&req1, req); 4171 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4172 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4173 def = req1.sym_out; 4174 defobj = req1.defobj_out; 4175 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4176 break; 4177 } 4178 } 4179 } 4180 if (def != NULL) { 4181 req->sym_out = def; 4182 req->defobj_out = defobj; 4183 return (0); 4184 } 4185 return (ESRCH); 4186 } 4187 4188 /* 4189 * Search the chain of DAGS cointed to by the given Needed_Entry 4190 * for a symbol of the given name. Each DAG is scanned completely 4191 * before advancing to the next one. Returns a pointer to the symbol, 4192 * or NULL if no definition was found. 4193 */ 4194 static int 4195 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4196 { 4197 const Elf_Sym *def; 4198 const Needed_Entry *n; 4199 const Obj_Entry *defobj; 4200 SymLook req1; 4201 int res; 4202 4203 def = NULL; 4204 defobj = NULL; 4205 symlook_init_from_req(&req1, req); 4206 for (n = needed; n != NULL; n = n->next) { 4207 if (n->obj == NULL || 4208 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4209 continue; 4210 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4211 def = req1.sym_out; 4212 defobj = req1.defobj_out; 4213 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4214 break; 4215 } 4216 } 4217 if (def != NULL) { 4218 req->sym_out = def; 4219 req->defobj_out = defobj; 4220 return (0); 4221 } 4222 return (ESRCH); 4223 } 4224 4225 /* 4226 * Search the symbol table of a single shared object for a symbol of 4227 * the given name and version, if requested. Returns a pointer to the 4228 * symbol, or NULL if no definition was found. If the object is 4229 * filter, return filtered symbol from filtee. 4230 * 4231 * The symbol's hash value is passed in for efficiency reasons; that 4232 * eliminates many recomputations of the hash value. 4233 */ 4234 int 4235 symlook_obj(SymLook *req, const Obj_Entry *obj) 4236 { 4237 DoneList donelist; 4238 SymLook req1; 4239 int flags, res, mres; 4240 4241 /* 4242 * If there is at least one valid hash at this point, we prefer to 4243 * use the faster GNU version if available. 4244 */ 4245 if (obj->valid_hash_gnu) 4246 mres = symlook_obj1_gnu(req, obj); 4247 else if (obj->valid_hash_sysv) 4248 mres = symlook_obj1_sysv(req, obj); 4249 else 4250 return (EINVAL); 4251 4252 if (mres == 0) { 4253 if (obj->needed_filtees != NULL) { 4254 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4255 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4256 donelist_init(&donelist); 4257 symlook_init_from_req(&req1, req); 4258 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4259 if (res == 0) { 4260 req->sym_out = req1.sym_out; 4261 req->defobj_out = req1.defobj_out; 4262 } 4263 return (res); 4264 } 4265 if (obj->needed_aux_filtees != NULL) { 4266 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4267 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4268 donelist_init(&donelist); 4269 symlook_init_from_req(&req1, req); 4270 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4271 if (res == 0) { 4272 req->sym_out = req1.sym_out; 4273 req->defobj_out = req1.defobj_out; 4274 return (res); 4275 } 4276 } 4277 } 4278 return (mres); 4279 } 4280 4281 /* Symbol match routine common to both hash functions */ 4282 static bool 4283 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4284 const unsigned long symnum) 4285 { 4286 Elf_Versym verndx; 4287 const Elf_Sym *symp; 4288 const char *strp; 4289 4290 symp = obj->symtab + symnum; 4291 strp = obj->strtab + symp->st_name; 4292 4293 switch (ELF_ST_TYPE(symp->st_info)) { 4294 case STT_FUNC: 4295 case STT_NOTYPE: 4296 case STT_OBJECT: 4297 case STT_COMMON: 4298 case STT_GNU_IFUNC: 4299 if (symp->st_value == 0) 4300 return (false); 4301 /* fallthrough */ 4302 case STT_TLS: 4303 if (symp->st_shndx != SHN_UNDEF) 4304 break; 4305 #ifndef __mips__ 4306 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4307 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4308 break; 4309 /* fallthrough */ 4310 #endif 4311 default: 4312 return (false); 4313 } 4314 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4315 return (false); 4316 4317 if (req->ventry == NULL) { 4318 if (obj->versyms != NULL) { 4319 verndx = VER_NDX(obj->versyms[symnum]); 4320 if (verndx > obj->vernum) { 4321 _rtld_error( 4322 "%s: symbol %s references wrong version %d", 4323 obj->path, obj->strtab + symnum, verndx); 4324 return (false); 4325 } 4326 /* 4327 * If we are not called from dlsym (i.e. this 4328 * is a normal relocation from unversioned 4329 * binary), accept the symbol immediately if 4330 * it happens to have first version after this 4331 * shared object became versioned. Otherwise, 4332 * if symbol is versioned and not hidden, 4333 * remember it. If it is the only symbol with 4334 * this name exported by the shared object, it 4335 * will be returned as a match by the calling 4336 * function. If symbol is global (verndx < 2) 4337 * accept it unconditionally. 4338 */ 4339 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4340 verndx == VER_NDX_GIVEN) { 4341 result->sym_out = symp; 4342 return (true); 4343 } 4344 else if (verndx >= VER_NDX_GIVEN) { 4345 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4346 == 0) { 4347 if (result->vsymp == NULL) 4348 result->vsymp = symp; 4349 result->vcount++; 4350 } 4351 return (false); 4352 } 4353 } 4354 result->sym_out = symp; 4355 return (true); 4356 } 4357 if (obj->versyms == NULL) { 4358 if (object_match_name(obj, req->ventry->name)) { 4359 _rtld_error("%s: object %s should provide version %s " 4360 "for symbol %s", obj_rtld.path, obj->path, 4361 req->ventry->name, obj->strtab + symnum); 4362 return (false); 4363 } 4364 } else { 4365 verndx = VER_NDX(obj->versyms[symnum]); 4366 if (verndx > obj->vernum) { 4367 _rtld_error("%s: symbol %s references wrong version %d", 4368 obj->path, obj->strtab + symnum, verndx); 4369 return (false); 4370 } 4371 if (obj->vertab[verndx].hash != req->ventry->hash || 4372 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4373 /* 4374 * Version does not match. Look if this is a 4375 * global symbol and if it is not hidden. If 4376 * global symbol (verndx < 2) is available, 4377 * use it. Do not return symbol if we are 4378 * called by dlvsym, because dlvsym looks for 4379 * a specific version and default one is not 4380 * what dlvsym wants. 4381 */ 4382 if ((req->flags & SYMLOOK_DLSYM) || 4383 (verndx >= VER_NDX_GIVEN) || 4384 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4385 return (false); 4386 } 4387 } 4388 result->sym_out = symp; 4389 return (true); 4390 } 4391 4392 /* 4393 * Search for symbol using SysV hash function. 4394 * obj->buckets is known not to be NULL at this point; the test for this was 4395 * performed with the obj->valid_hash_sysv assignment. 4396 */ 4397 static int 4398 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4399 { 4400 unsigned long symnum; 4401 Sym_Match_Result matchres; 4402 4403 matchres.sym_out = NULL; 4404 matchres.vsymp = NULL; 4405 matchres.vcount = 0; 4406 4407 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4408 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4409 if (symnum >= obj->nchains) 4410 return (ESRCH); /* Bad object */ 4411 4412 if (matched_symbol(req, obj, &matchres, symnum)) { 4413 req->sym_out = matchres.sym_out; 4414 req->defobj_out = obj; 4415 return (0); 4416 } 4417 } 4418 if (matchres.vcount == 1) { 4419 req->sym_out = matchres.vsymp; 4420 req->defobj_out = obj; 4421 return (0); 4422 } 4423 return (ESRCH); 4424 } 4425 4426 /* Search for symbol using GNU hash function */ 4427 static int 4428 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4429 { 4430 Elf_Addr bloom_word; 4431 const Elf32_Word *hashval; 4432 Elf32_Word bucket; 4433 Sym_Match_Result matchres; 4434 unsigned int h1, h2; 4435 unsigned long symnum; 4436 4437 matchres.sym_out = NULL; 4438 matchres.vsymp = NULL; 4439 matchres.vcount = 0; 4440 4441 /* Pick right bitmask word from Bloom filter array */ 4442 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4443 obj->maskwords_bm_gnu]; 4444 4445 /* Calculate modulus word size of gnu hash and its derivative */ 4446 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4447 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4448 4449 /* Filter out the "definitely not in set" queries */ 4450 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4451 return (ESRCH); 4452 4453 /* Locate hash chain and corresponding value element*/ 4454 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4455 if (bucket == 0) 4456 return (ESRCH); 4457 hashval = &obj->chain_zero_gnu[bucket]; 4458 do { 4459 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4460 symnum = hashval - obj->chain_zero_gnu; 4461 if (matched_symbol(req, obj, &matchres, symnum)) { 4462 req->sym_out = matchres.sym_out; 4463 req->defobj_out = obj; 4464 return (0); 4465 } 4466 } 4467 } while ((*hashval++ & 1) == 0); 4468 if (matchres.vcount == 1) { 4469 req->sym_out = matchres.vsymp; 4470 req->defobj_out = obj; 4471 return (0); 4472 } 4473 return (ESRCH); 4474 } 4475 4476 static void 4477 trace_loaded_objects(Obj_Entry *obj) 4478 { 4479 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4480 int c; 4481 4482 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4483 main_local = ""; 4484 4485 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4486 fmt1 = "\t%o => %p (%x)\n"; 4487 4488 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4489 fmt2 = "\t%o (%x)\n"; 4490 4491 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4492 4493 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4494 Needed_Entry *needed; 4495 char *name, *path; 4496 bool is_lib; 4497 4498 if (obj->marker) 4499 continue; 4500 if (list_containers && obj->needed != NULL) 4501 rtld_printf("%s:\n", obj->path); 4502 for (needed = obj->needed; needed; needed = needed->next) { 4503 if (needed->obj != NULL) { 4504 if (needed->obj->traced && !list_containers) 4505 continue; 4506 needed->obj->traced = true; 4507 path = needed->obj->path; 4508 } else 4509 path = "not found"; 4510 4511 name = (char *)obj->strtab + needed->name; 4512 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4513 4514 fmt = is_lib ? fmt1 : fmt2; 4515 while ((c = *fmt++) != '\0') { 4516 switch (c) { 4517 default: 4518 rtld_putchar(c); 4519 continue; 4520 case '\\': 4521 switch (c = *fmt) { 4522 case '\0': 4523 continue; 4524 case 'n': 4525 rtld_putchar('\n'); 4526 break; 4527 case 't': 4528 rtld_putchar('\t'); 4529 break; 4530 } 4531 break; 4532 case '%': 4533 switch (c = *fmt) { 4534 case '\0': 4535 continue; 4536 case '%': 4537 default: 4538 rtld_putchar(c); 4539 break; 4540 case 'A': 4541 rtld_putstr(main_local); 4542 break; 4543 case 'a': 4544 rtld_putstr(obj_main->path); 4545 break; 4546 case 'o': 4547 rtld_putstr(name); 4548 break; 4549 #if 0 4550 case 'm': 4551 rtld_printf("%d", sodp->sod_major); 4552 break; 4553 case 'n': 4554 rtld_printf("%d", sodp->sod_minor); 4555 break; 4556 #endif 4557 case 'p': 4558 rtld_putstr(path); 4559 break; 4560 case 'x': 4561 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4562 0); 4563 break; 4564 } 4565 break; 4566 } 4567 ++fmt; 4568 } 4569 } 4570 } 4571 } 4572 4573 /* 4574 * Unload a dlopened object and its dependencies from memory and from 4575 * our data structures. It is assumed that the DAG rooted in the 4576 * object has already been unreferenced, and that the object has a 4577 * reference count of 0. 4578 */ 4579 static void 4580 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4581 { 4582 Obj_Entry marker, *obj, *next; 4583 4584 assert(root->refcount == 0); 4585 4586 /* 4587 * Pass over the DAG removing unreferenced objects from 4588 * appropriate lists. 4589 */ 4590 unlink_object(root); 4591 4592 /* Unmap all objects that are no longer referenced. */ 4593 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4594 next = TAILQ_NEXT(obj, next); 4595 if (obj->marker || obj->refcount != 0) 4596 continue; 4597 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4598 obj->mapsize, 0, obj->path); 4599 dbg("unloading \"%s\"", obj->path); 4600 /* 4601 * Unlink the object now to prevent new references from 4602 * being acquired while the bind lock is dropped in 4603 * recursive dlclose() invocations. 4604 */ 4605 TAILQ_REMOVE(&obj_list, obj, next); 4606 obj_count--; 4607 4608 if (obj->filtees_loaded) { 4609 if (next != NULL) { 4610 init_marker(&marker); 4611 TAILQ_INSERT_BEFORE(next, &marker, next); 4612 unload_filtees(obj, lockstate); 4613 next = TAILQ_NEXT(&marker, next); 4614 TAILQ_REMOVE(&obj_list, &marker, next); 4615 } else 4616 unload_filtees(obj, lockstate); 4617 } 4618 release_object(obj); 4619 } 4620 } 4621 4622 static void 4623 unlink_object(Obj_Entry *root) 4624 { 4625 Objlist_Entry *elm; 4626 4627 if (root->refcount == 0) { 4628 /* Remove the object from the RTLD_GLOBAL list. */ 4629 objlist_remove(&list_global, root); 4630 4631 /* Remove the object from all objects' DAG lists. */ 4632 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4633 objlist_remove(&elm->obj->dldags, root); 4634 if (elm->obj != root) 4635 unlink_object(elm->obj); 4636 } 4637 } 4638 } 4639 4640 static void 4641 ref_dag(Obj_Entry *root) 4642 { 4643 Objlist_Entry *elm; 4644 4645 assert(root->dag_inited); 4646 STAILQ_FOREACH(elm, &root->dagmembers, link) 4647 elm->obj->refcount++; 4648 } 4649 4650 static void 4651 unref_dag(Obj_Entry *root) 4652 { 4653 Objlist_Entry *elm; 4654 4655 assert(root->dag_inited); 4656 STAILQ_FOREACH(elm, &root->dagmembers, link) 4657 elm->obj->refcount--; 4658 } 4659 4660 /* 4661 * Common code for MD __tls_get_addr(). 4662 */ 4663 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4664 static void * 4665 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4666 { 4667 Elf_Addr *newdtv, *dtv; 4668 RtldLockState lockstate; 4669 int to_copy; 4670 4671 dtv = *dtvp; 4672 /* Check dtv generation in case new modules have arrived */ 4673 if (dtv[0] != tls_dtv_generation) { 4674 wlock_acquire(rtld_bind_lock, &lockstate); 4675 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4676 to_copy = dtv[1]; 4677 if (to_copy > tls_max_index) 4678 to_copy = tls_max_index; 4679 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4680 newdtv[0] = tls_dtv_generation; 4681 newdtv[1] = tls_max_index; 4682 free(dtv); 4683 lock_release(rtld_bind_lock, &lockstate); 4684 dtv = *dtvp = newdtv; 4685 } 4686 4687 /* Dynamically allocate module TLS if necessary */ 4688 if (dtv[index + 1] == 0) { 4689 /* Signal safe, wlock will block out signals. */ 4690 wlock_acquire(rtld_bind_lock, &lockstate); 4691 if (!dtv[index + 1]) 4692 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4693 lock_release(rtld_bind_lock, &lockstate); 4694 } 4695 return ((void *)(dtv[index + 1] + offset)); 4696 } 4697 4698 void * 4699 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4700 { 4701 Elf_Addr *dtv; 4702 4703 dtv = *dtvp; 4704 /* Check dtv generation in case new modules have arrived */ 4705 if (__predict_true(dtv[0] == tls_dtv_generation && 4706 dtv[index + 1] != 0)) 4707 return ((void *)(dtv[index + 1] + offset)); 4708 return (tls_get_addr_slow(dtvp, index, offset)); 4709 } 4710 4711 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4712 defined(__powerpc__) || defined(__riscv) 4713 4714 /* 4715 * Return pointer to allocated TLS block 4716 */ 4717 static void * 4718 get_tls_block_ptr(void *tcb, size_t tcbsize) 4719 { 4720 size_t extra_size, post_size, pre_size, tls_block_size; 4721 size_t tls_init_align; 4722 4723 tls_init_align = MAX(obj_main->tlsalign, 1); 4724 4725 /* Compute fragments sizes. */ 4726 extra_size = tcbsize - TLS_TCB_SIZE; 4727 post_size = calculate_tls_post_size(tls_init_align); 4728 tls_block_size = tcbsize + post_size; 4729 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4730 4731 return ((char *)tcb - pre_size - extra_size); 4732 } 4733 4734 /* 4735 * Allocate Static TLS using the Variant I method. 4736 * 4737 * For details on the layout, see lib/libc/gen/tls.c. 4738 * 4739 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4740 * it is based on tls_last_offset, and TLS offsets here are really TCB 4741 * offsets, whereas libc's tls_static_space is just the executable's static 4742 * TLS segment. 4743 */ 4744 void * 4745 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4746 { 4747 Obj_Entry *obj; 4748 char *tls_block; 4749 Elf_Addr *dtv, **tcb; 4750 Elf_Addr addr; 4751 int i; 4752 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4753 size_t tls_init_align; 4754 4755 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4756 return (oldtcb); 4757 4758 assert(tcbsize >= TLS_TCB_SIZE); 4759 maxalign = MAX(tcbalign, tls_static_max_align); 4760 tls_init_align = MAX(obj_main->tlsalign, 1); 4761 4762 /* Compute fragmets sizes. */ 4763 extra_size = tcbsize - TLS_TCB_SIZE; 4764 post_size = calculate_tls_post_size(tls_init_align); 4765 tls_block_size = tcbsize + post_size; 4766 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4767 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4768 4769 /* Allocate whole TLS block */ 4770 tls_block = malloc_aligned(tls_block_size, maxalign); 4771 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4772 4773 if (oldtcb != NULL) { 4774 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4775 tls_static_space); 4776 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4777 4778 /* Adjust the DTV. */ 4779 dtv = tcb[0]; 4780 for (i = 0; i < dtv[1]; i++) { 4781 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4782 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4783 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4784 } 4785 } 4786 } else { 4787 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4788 tcb[0] = dtv; 4789 dtv[0] = tls_dtv_generation; 4790 dtv[1] = tls_max_index; 4791 4792 for (obj = globallist_curr(objs); obj != NULL; 4793 obj = globallist_next(obj)) { 4794 if (obj->tlsoffset > 0) { 4795 addr = (Elf_Addr)tcb + obj->tlsoffset; 4796 if (obj->tlsinitsize > 0) 4797 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4798 if (obj->tlssize > obj->tlsinitsize) 4799 memset((void*) (addr + obj->tlsinitsize), 0, 4800 obj->tlssize - obj->tlsinitsize); 4801 dtv[obj->tlsindex + 1] = addr; 4802 } 4803 } 4804 } 4805 4806 return (tcb); 4807 } 4808 4809 void 4810 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4811 { 4812 Elf_Addr *dtv; 4813 Elf_Addr tlsstart, tlsend; 4814 size_t post_size; 4815 size_t dtvsize, i, tls_init_align; 4816 4817 assert(tcbsize >= TLS_TCB_SIZE); 4818 tls_init_align = MAX(obj_main->tlsalign, 1); 4819 4820 /* Compute fragments sizes. */ 4821 post_size = calculate_tls_post_size(tls_init_align); 4822 4823 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4824 tlsend = (Elf_Addr)tcb + tls_static_space; 4825 4826 dtv = *(Elf_Addr **)tcb; 4827 dtvsize = dtv[1]; 4828 for (i = 0; i < dtvsize; i++) { 4829 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4830 free((void*)dtv[i+2]); 4831 } 4832 } 4833 free(dtv); 4834 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4835 } 4836 4837 #endif 4838 4839 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4840 4841 /* 4842 * Allocate Static TLS using the Variant II method. 4843 */ 4844 void * 4845 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4846 { 4847 Obj_Entry *obj; 4848 size_t size, ralign; 4849 char *tls; 4850 Elf_Addr *dtv, *olddtv; 4851 Elf_Addr segbase, oldsegbase, addr; 4852 int i; 4853 4854 ralign = tcbalign; 4855 if (tls_static_max_align > ralign) 4856 ralign = tls_static_max_align; 4857 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4858 4859 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4860 tls = malloc_aligned(size, ralign); 4861 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4862 4863 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4864 ((Elf_Addr*)segbase)[0] = segbase; 4865 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4866 4867 dtv[0] = tls_dtv_generation; 4868 dtv[1] = tls_max_index; 4869 4870 if (oldtls) { 4871 /* 4872 * Copy the static TLS block over whole. 4873 */ 4874 oldsegbase = (Elf_Addr) oldtls; 4875 memcpy((void *)(segbase - tls_static_space), 4876 (const void *)(oldsegbase - tls_static_space), 4877 tls_static_space); 4878 4879 /* 4880 * If any dynamic TLS blocks have been created tls_get_addr(), 4881 * move them over. 4882 */ 4883 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4884 for (i = 0; i < olddtv[1]; i++) { 4885 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4886 dtv[i+2] = olddtv[i+2]; 4887 olddtv[i+2] = 0; 4888 } 4889 } 4890 4891 /* 4892 * We assume that this block was the one we created with 4893 * allocate_initial_tls(). 4894 */ 4895 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4896 } else { 4897 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4898 if (obj->marker || obj->tlsoffset == 0) 4899 continue; 4900 addr = segbase - obj->tlsoffset; 4901 memset((void*) (addr + obj->tlsinitsize), 4902 0, obj->tlssize - obj->tlsinitsize); 4903 if (obj->tlsinit) 4904 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4905 dtv[obj->tlsindex + 1] = addr; 4906 } 4907 } 4908 4909 return (void*) segbase; 4910 } 4911 4912 void 4913 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4914 { 4915 Elf_Addr* dtv; 4916 size_t size, ralign; 4917 int dtvsize, i; 4918 Elf_Addr tlsstart, tlsend; 4919 4920 /* 4921 * Figure out the size of the initial TLS block so that we can 4922 * find stuff which ___tls_get_addr() allocated dynamically. 4923 */ 4924 ralign = tcbalign; 4925 if (tls_static_max_align > ralign) 4926 ralign = tls_static_max_align; 4927 size = round(tls_static_space, ralign); 4928 4929 dtv = ((Elf_Addr**)tls)[1]; 4930 dtvsize = dtv[1]; 4931 tlsend = (Elf_Addr) tls; 4932 tlsstart = tlsend - size; 4933 for (i = 0; i < dtvsize; i++) { 4934 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4935 free_aligned((void *)dtv[i + 2]); 4936 } 4937 } 4938 4939 free_aligned((void *)tlsstart); 4940 free((void*) dtv); 4941 } 4942 4943 #endif 4944 4945 /* 4946 * Allocate TLS block for module with given index. 4947 */ 4948 void * 4949 allocate_module_tls(int index) 4950 { 4951 Obj_Entry* obj; 4952 char* p; 4953 4954 TAILQ_FOREACH(obj, &obj_list, next) { 4955 if (obj->marker) 4956 continue; 4957 if (obj->tlsindex == index) 4958 break; 4959 } 4960 if (!obj) { 4961 _rtld_error("Can't find module with TLS index %d", index); 4962 rtld_die(); 4963 } 4964 4965 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4966 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4967 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4968 4969 return p; 4970 } 4971 4972 bool 4973 allocate_tls_offset(Obj_Entry *obj) 4974 { 4975 size_t off; 4976 4977 if (obj->tls_done) 4978 return true; 4979 4980 if (obj->tlssize == 0) { 4981 obj->tls_done = true; 4982 return true; 4983 } 4984 4985 if (tls_last_offset == 0) 4986 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4987 else 4988 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4989 obj->tlssize, obj->tlsalign); 4990 4991 /* 4992 * If we have already fixed the size of the static TLS block, we 4993 * must stay within that size. When allocating the static TLS, we 4994 * leave a small amount of space spare to be used for dynamically 4995 * loading modules which use static TLS. 4996 */ 4997 if (tls_static_space != 0) { 4998 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4999 return false; 5000 } else if (obj->tlsalign > tls_static_max_align) { 5001 tls_static_max_align = obj->tlsalign; 5002 } 5003 5004 tls_last_offset = obj->tlsoffset = off; 5005 tls_last_size = obj->tlssize; 5006 obj->tls_done = true; 5007 5008 return true; 5009 } 5010 5011 void 5012 free_tls_offset(Obj_Entry *obj) 5013 { 5014 5015 /* 5016 * If we were the last thing to allocate out of the static TLS 5017 * block, we give our space back to the 'allocator'. This is a 5018 * simplistic workaround to allow libGL.so.1 to be loaded and 5019 * unloaded multiple times. 5020 */ 5021 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5022 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5023 tls_last_offset -= obj->tlssize; 5024 tls_last_size = 0; 5025 } 5026 } 5027 5028 void * 5029 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5030 { 5031 void *ret; 5032 RtldLockState lockstate; 5033 5034 wlock_acquire(rtld_bind_lock, &lockstate); 5035 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5036 tcbsize, tcbalign); 5037 lock_release(rtld_bind_lock, &lockstate); 5038 return (ret); 5039 } 5040 5041 void 5042 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5043 { 5044 RtldLockState lockstate; 5045 5046 wlock_acquire(rtld_bind_lock, &lockstate); 5047 free_tls(tcb, tcbsize, tcbalign); 5048 lock_release(rtld_bind_lock, &lockstate); 5049 } 5050 5051 static void 5052 object_add_name(Obj_Entry *obj, const char *name) 5053 { 5054 Name_Entry *entry; 5055 size_t len; 5056 5057 len = strlen(name); 5058 entry = malloc(sizeof(Name_Entry) + len); 5059 5060 if (entry != NULL) { 5061 strcpy(entry->name, name); 5062 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5063 } 5064 } 5065 5066 static int 5067 object_match_name(const Obj_Entry *obj, const char *name) 5068 { 5069 Name_Entry *entry; 5070 5071 STAILQ_FOREACH(entry, &obj->names, link) { 5072 if (strcmp(name, entry->name) == 0) 5073 return (1); 5074 } 5075 return (0); 5076 } 5077 5078 static Obj_Entry * 5079 locate_dependency(const Obj_Entry *obj, const char *name) 5080 { 5081 const Objlist_Entry *entry; 5082 const Needed_Entry *needed; 5083 5084 STAILQ_FOREACH(entry, &list_main, link) { 5085 if (object_match_name(entry->obj, name)) 5086 return entry->obj; 5087 } 5088 5089 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5090 if (strcmp(obj->strtab + needed->name, name) == 0 || 5091 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5092 /* 5093 * If there is DT_NEEDED for the name we are looking for, 5094 * we are all set. Note that object might not be found if 5095 * dependency was not loaded yet, so the function can 5096 * return NULL here. This is expected and handled 5097 * properly by the caller. 5098 */ 5099 return (needed->obj); 5100 } 5101 } 5102 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5103 obj->path, name); 5104 rtld_die(); 5105 } 5106 5107 static int 5108 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5109 const Elf_Vernaux *vna) 5110 { 5111 const Elf_Verdef *vd; 5112 const char *vername; 5113 5114 vername = refobj->strtab + vna->vna_name; 5115 vd = depobj->verdef; 5116 if (vd == NULL) { 5117 _rtld_error("%s: version %s required by %s not defined", 5118 depobj->path, vername, refobj->path); 5119 return (-1); 5120 } 5121 for (;;) { 5122 if (vd->vd_version != VER_DEF_CURRENT) { 5123 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5124 depobj->path, vd->vd_version); 5125 return (-1); 5126 } 5127 if (vna->vna_hash == vd->vd_hash) { 5128 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5129 ((char *)vd + vd->vd_aux); 5130 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5131 return (0); 5132 } 5133 if (vd->vd_next == 0) 5134 break; 5135 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5136 } 5137 if (vna->vna_flags & VER_FLG_WEAK) 5138 return (0); 5139 _rtld_error("%s: version %s required by %s not found", 5140 depobj->path, vername, refobj->path); 5141 return (-1); 5142 } 5143 5144 static int 5145 rtld_verify_object_versions(Obj_Entry *obj) 5146 { 5147 const Elf_Verneed *vn; 5148 const Elf_Verdef *vd; 5149 const Elf_Verdaux *vda; 5150 const Elf_Vernaux *vna; 5151 const Obj_Entry *depobj; 5152 int maxvernum, vernum; 5153 5154 if (obj->ver_checked) 5155 return (0); 5156 obj->ver_checked = true; 5157 5158 maxvernum = 0; 5159 /* 5160 * Walk over defined and required version records and figure out 5161 * max index used by any of them. Do very basic sanity checking 5162 * while there. 5163 */ 5164 vn = obj->verneed; 5165 while (vn != NULL) { 5166 if (vn->vn_version != VER_NEED_CURRENT) { 5167 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5168 obj->path, vn->vn_version); 5169 return (-1); 5170 } 5171 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5172 for (;;) { 5173 vernum = VER_NEED_IDX(vna->vna_other); 5174 if (vernum > maxvernum) 5175 maxvernum = vernum; 5176 if (vna->vna_next == 0) 5177 break; 5178 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5179 } 5180 if (vn->vn_next == 0) 5181 break; 5182 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5183 } 5184 5185 vd = obj->verdef; 5186 while (vd != NULL) { 5187 if (vd->vd_version != VER_DEF_CURRENT) { 5188 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5189 obj->path, vd->vd_version); 5190 return (-1); 5191 } 5192 vernum = VER_DEF_IDX(vd->vd_ndx); 5193 if (vernum > maxvernum) 5194 maxvernum = vernum; 5195 if (vd->vd_next == 0) 5196 break; 5197 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5198 } 5199 5200 if (maxvernum == 0) 5201 return (0); 5202 5203 /* 5204 * Store version information in array indexable by version index. 5205 * Verify that object version requirements are satisfied along the 5206 * way. 5207 */ 5208 obj->vernum = maxvernum + 1; 5209 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5210 5211 vd = obj->verdef; 5212 while (vd != NULL) { 5213 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5214 vernum = VER_DEF_IDX(vd->vd_ndx); 5215 assert(vernum <= maxvernum); 5216 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5217 obj->vertab[vernum].hash = vd->vd_hash; 5218 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5219 obj->vertab[vernum].file = NULL; 5220 obj->vertab[vernum].flags = 0; 5221 } 5222 if (vd->vd_next == 0) 5223 break; 5224 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5225 } 5226 5227 vn = obj->verneed; 5228 while (vn != NULL) { 5229 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5230 if (depobj == NULL) 5231 return (-1); 5232 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5233 for (;;) { 5234 if (check_object_provided_version(obj, depobj, vna)) 5235 return (-1); 5236 vernum = VER_NEED_IDX(vna->vna_other); 5237 assert(vernum <= maxvernum); 5238 obj->vertab[vernum].hash = vna->vna_hash; 5239 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5240 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5241 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5242 VER_INFO_HIDDEN : 0; 5243 if (vna->vna_next == 0) 5244 break; 5245 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5246 } 5247 if (vn->vn_next == 0) 5248 break; 5249 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5250 } 5251 return 0; 5252 } 5253 5254 static int 5255 rtld_verify_versions(const Objlist *objlist) 5256 { 5257 Objlist_Entry *entry; 5258 int rc; 5259 5260 rc = 0; 5261 STAILQ_FOREACH(entry, objlist, link) { 5262 /* 5263 * Skip dummy objects or objects that have their version requirements 5264 * already checked. 5265 */ 5266 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5267 continue; 5268 if (rtld_verify_object_versions(entry->obj) == -1) { 5269 rc = -1; 5270 if (ld_tracing == NULL) 5271 break; 5272 } 5273 } 5274 if (rc == 0 || ld_tracing != NULL) 5275 rc = rtld_verify_object_versions(&obj_rtld); 5276 return rc; 5277 } 5278 5279 const Ver_Entry * 5280 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5281 { 5282 Elf_Versym vernum; 5283 5284 if (obj->vertab) { 5285 vernum = VER_NDX(obj->versyms[symnum]); 5286 if (vernum >= obj->vernum) { 5287 _rtld_error("%s: symbol %s has wrong verneed value %d", 5288 obj->path, obj->strtab + symnum, vernum); 5289 } else if (obj->vertab[vernum].hash != 0) { 5290 return &obj->vertab[vernum]; 5291 } 5292 } 5293 return NULL; 5294 } 5295 5296 int 5297 _rtld_get_stack_prot(void) 5298 { 5299 5300 return (stack_prot); 5301 } 5302 5303 int 5304 _rtld_is_dlopened(void *arg) 5305 { 5306 Obj_Entry *obj; 5307 RtldLockState lockstate; 5308 int res; 5309 5310 rlock_acquire(rtld_bind_lock, &lockstate); 5311 obj = dlcheck(arg); 5312 if (obj == NULL) 5313 obj = obj_from_addr(arg); 5314 if (obj == NULL) { 5315 _rtld_error("No shared object contains address"); 5316 lock_release(rtld_bind_lock, &lockstate); 5317 return (-1); 5318 } 5319 res = obj->dlopened ? 1 : 0; 5320 lock_release(rtld_bind_lock, &lockstate); 5321 return (res); 5322 } 5323 5324 static int 5325 obj_remap_relro(Obj_Entry *obj, int prot) 5326 { 5327 5328 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5329 prot) == -1) { 5330 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5331 obj->path, prot, rtld_strerror(errno)); 5332 return (-1); 5333 } 5334 return (0); 5335 } 5336 5337 static int 5338 obj_disable_relro(Obj_Entry *obj) 5339 { 5340 5341 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5342 } 5343 5344 static int 5345 obj_enforce_relro(Obj_Entry *obj) 5346 { 5347 5348 return (obj_remap_relro(obj, PROT_READ)); 5349 } 5350 5351 static void 5352 map_stacks_exec(RtldLockState *lockstate) 5353 { 5354 void (*thr_map_stacks_exec)(void); 5355 5356 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5357 return; 5358 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5359 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5360 if (thr_map_stacks_exec != NULL) { 5361 stack_prot |= PROT_EXEC; 5362 thr_map_stacks_exec(); 5363 } 5364 } 5365 5366 void 5367 symlook_init(SymLook *dst, const char *name) 5368 { 5369 5370 bzero(dst, sizeof(*dst)); 5371 dst->name = name; 5372 dst->hash = elf_hash(name); 5373 dst->hash_gnu = gnu_hash(name); 5374 } 5375 5376 static void 5377 symlook_init_from_req(SymLook *dst, const SymLook *src) 5378 { 5379 5380 dst->name = src->name; 5381 dst->hash = src->hash; 5382 dst->hash_gnu = src->hash_gnu; 5383 dst->ventry = src->ventry; 5384 dst->flags = src->flags; 5385 dst->defobj_out = NULL; 5386 dst->sym_out = NULL; 5387 dst->lockstate = src->lockstate; 5388 } 5389 5390 static int 5391 open_binary_fd(const char *argv0, bool search_in_path) 5392 { 5393 char *pathenv, *pe, binpath[PATH_MAX]; 5394 int fd; 5395 5396 if (search_in_path && strchr(argv0, '/') == NULL) { 5397 pathenv = getenv("PATH"); 5398 if (pathenv == NULL) { 5399 _rtld_error("-p and no PATH environment variable"); 5400 rtld_die(); 5401 } 5402 pathenv = strdup(pathenv); 5403 if (pathenv == NULL) { 5404 _rtld_error("Cannot allocate memory"); 5405 rtld_die(); 5406 } 5407 fd = -1; 5408 errno = ENOENT; 5409 while ((pe = strsep(&pathenv, ":")) != NULL) { 5410 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5411 sizeof(binpath)) 5412 continue; 5413 if (binpath[0] != '\0' && 5414 strlcat(binpath, "/", sizeof(binpath)) >= 5415 sizeof(binpath)) 5416 continue; 5417 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5418 sizeof(binpath)) 5419 continue; 5420 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5421 if (fd != -1 || errno != ENOENT) 5422 break; 5423 } 5424 free(pathenv); 5425 } else { 5426 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5427 } 5428 5429 if (fd == -1) { 5430 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5431 rtld_die(); 5432 } 5433 return (fd); 5434 } 5435 5436 /* 5437 * Parse a set of command-line arguments. 5438 */ 5439 static int 5440 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5441 { 5442 const char *arg; 5443 int fd, i, j, arglen; 5444 char opt; 5445 5446 dbg("Parsing command-line arguments"); 5447 *use_pathp = false; 5448 *fdp = -1; 5449 5450 for (i = 1; i < argc; i++ ) { 5451 arg = argv[i]; 5452 dbg("argv[%d]: '%s'", i, arg); 5453 5454 /* 5455 * rtld arguments end with an explicit "--" or with the first 5456 * non-prefixed argument. 5457 */ 5458 if (strcmp(arg, "--") == 0) { 5459 i++; 5460 break; 5461 } 5462 if (arg[0] != '-') 5463 break; 5464 5465 /* 5466 * All other arguments are single-character options that can 5467 * be combined, so we need to search through `arg` for them. 5468 */ 5469 arglen = strlen(arg); 5470 for (j = 1; j < arglen; j++) { 5471 opt = arg[j]; 5472 if (opt == 'h') { 5473 print_usage(argv[0]); 5474 _exit(0); 5475 } else if (opt == 'f') { 5476 /* 5477 * -f XX can be used to specify a descriptor for the 5478 * binary named at the command line (i.e., the later 5479 * argument will specify the process name but the 5480 * descriptor is what will actually be executed) 5481 */ 5482 if (j != arglen - 1) { 5483 /* -f must be the last option in, e.g., -abcf */ 5484 _rtld_error("Invalid options: %s", arg); 5485 rtld_die(); 5486 } 5487 i++; 5488 fd = parse_integer(argv[i]); 5489 if (fd == -1) { 5490 _rtld_error("Invalid file descriptor: '%s'", 5491 argv[i]); 5492 rtld_die(); 5493 } 5494 *fdp = fd; 5495 break; 5496 } else if (opt == 'p') { 5497 *use_pathp = true; 5498 } else { 5499 _rtld_error("Invalid argument: '%s'", arg); 5500 print_usage(argv[0]); 5501 rtld_die(); 5502 } 5503 } 5504 } 5505 5506 return (i); 5507 } 5508 5509 /* 5510 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5511 */ 5512 static int 5513 parse_integer(const char *str) 5514 { 5515 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5516 const char *orig; 5517 int n; 5518 char c; 5519 5520 orig = str; 5521 n = 0; 5522 for (c = *str; c != '\0'; c = *++str) { 5523 if (c < '0' || c > '9') 5524 return (-1); 5525 5526 n *= RADIX; 5527 n += c - '0'; 5528 } 5529 5530 /* Make sure we actually parsed something. */ 5531 if (str == orig) 5532 return (-1); 5533 return (n); 5534 } 5535 5536 static void 5537 print_usage(const char *argv0) 5538 { 5539 5540 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5541 "\n" 5542 "Options:\n" 5543 " -h Display this help message\n" 5544 " -p Search in PATH for named binary\n" 5545 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5546 " -- End of RTLD options\n" 5547 " <binary> Name of process to execute\n" 5548 " <args> Arguments to the executed process\n", argv0); 5549 } 5550 5551 /* 5552 * Overrides for libc_pic-provided functions. 5553 */ 5554 5555 int 5556 __getosreldate(void) 5557 { 5558 size_t len; 5559 int oid[2]; 5560 int error, osrel; 5561 5562 if (osreldate != 0) 5563 return (osreldate); 5564 5565 oid[0] = CTL_KERN; 5566 oid[1] = KERN_OSRELDATE; 5567 osrel = 0; 5568 len = sizeof(osrel); 5569 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5570 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5571 osreldate = osrel; 5572 return (osreldate); 5573 } 5574 5575 void 5576 exit(int status) 5577 { 5578 5579 _exit(status); 5580 } 5581 5582 void (*__cleanup)(void); 5583 int __isthreaded = 0; 5584 int _thread_autoinit_dummy_decl = 1; 5585 5586 /* 5587 * No unresolved symbols for rtld. 5588 */ 5589 void 5590 __pthread_cxa_finalize(struct dl_phdr_info *a) 5591 { 5592 } 5593 5594 const char * 5595 rtld_strerror(int errnum) 5596 { 5597 5598 if (errnum < 0 || errnum >= sys_nerr) 5599 return ("Unknown error"); 5600 return (sys_errlist[errnum]); 5601 } 5602 5603 /* 5604 * No ifunc relocations. 5605 */ 5606 void * 5607 memset(void *dest, int c, size_t len) 5608 { 5609 size_t i; 5610 5611 for (i = 0; i < len; i++) 5612 ((char *)dest)[i] = c; 5613 return (dest); 5614 } 5615 5616 void 5617 bzero(void *dest, size_t len) 5618 { 5619 size_t i; 5620 5621 for (i = 0; i < len; i++) 5622 ((char *)dest)[i] = 0; 5623 } 5624