1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(void); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 78 /* Variables that cannot be static: */ 79 extern struct r_debug r_debug; /* For GDB */ 80 extern int _thread_autoinit_dummy_decl; 81 extern char* __progname; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static void digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path); 138 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 139 static int parse_integer(const char *); 140 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 141 static void print_usage(const char *argv0); 142 static void release_object(Obj_Entry *); 143 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 144 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 145 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 146 int flags, RtldLockState *lockstate); 147 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 148 RtldLockState *); 149 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 150 static int rtld_dirname(const char *, char *); 151 static int rtld_dirname_abs(const char *, char *); 152 static void *rtld_dlopen(const char *name, int fd, int mode); 153 static void rtld_exit(void); 154 static void rtld_nop_exit(void); 155 static char *search_library_path(const char *, const char *, const char *, 156 int *); 157 static char *search_library_pathfds(const char *, const char *, int *); 158 static const void **get_program_var_addr(const char *, RtldLockState *); 159 static void set_program_var(const char *, const void *); 160 static int symlook_default(SymLook *, const Obj_Entry *refobj); 161 static int symlook_global(SymLook *, DoneList *); 162 static void symlook_init_from_req(SymLook *, const SymLook *); 163 static int symlook_list(SymLook *, const Objlist *, DoneList *); 164 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 165 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 166 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 167 static void trace_loaded_objects(Obj_Entry *); 168 static void unlink_object(Obj_Entry *); 169 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 170 static void unref_dag(Obj_Entry *); 171 static void ref_dag(Obj_Entry *); 172 static char *origin_subst_one(Obj_Entry *, char *, const char *, 173 const char *, bool); 174 static char *origin_subst(Obj_Entry *, const char *); 175 static bool obj_resolve_origin(Obj_Entry *obj); 176 static void preinit_main(void); 177 static int rtld_verify_versions(const Objlist *); 178 static int rtld_verify_object_versions(Obj_Entry *); 179 static void object_add_name(Obj_Entry *, const char *); 180 static int object_match_name(const Obj_Entry *, const char *); 181 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 182 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 183 struct dl_phdr_info *phdr_info); 184 static uint32_t gnu_hash(const char *); 185 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 186 const unsigned long); 187 188 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 189 void _r_debug_postinit(struct link_map *) __noinline __exported; 190 191 int __sys_openat(int, const char *, int, ...); 192 193 /* 194 * Data declarations. 195 */ 196 static char *error_message; /* Message for dlerror(), or NULL */ 197 struct r_debug r_debug __exported; /* for GDB; */ 198 static bool libmap_disable; /* Disable libmap */ 199 static bool ld_loadfltr; /* Immediate filters processing */ 200 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 201 static bool trust; /* False for setuid and setgid programs */ 202 static bool dangerous_ld_env; /* True if environment variables have been 203 used to affect the libraries loaded */ 204 bool ld_bind_not; /* Disable PLT update */ 205 static char *ld_bind_now; /* Environment variable for immediate binding */ 206 static char *ld_debug; /* Environment variable for debugging */ 207 static char *ld_library_path; /* Environment variable for search path */ 208 static char *ld_library_dirs; /* Environment variable for library descriptors */ 209 static char *ld_preload; /* Environment variable for libraries to 210 load first */ 211 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 212 static const char *ld_tracing; /* Called from ldd to print libs */ 213 static char *ld_utrace; /* Use utrace() to log events. */ 214 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 215 static Obj_Entry *obj_main; /* The main program shared object */ 216 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 217 static unsigned int obj_count; /* Number of objects in obj_list */ 218 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 219 220 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 221 STAILQ_HEAD_INITIALIZER(list_global); 222 static Objlist list_main = /* Objects loaded at program startup */ 223 STAILQ_HEAD_INITIALIZER(list_main); 224 static Objlist list_fini = /* Objects needing fini() calls */ 225 STAILQ_HEAD_INITIALIZER(list_fini); 226 227 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 228 229 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 230 231 extern Elf_Dyn _DYNAMIC; 232 #pragma weak _DYNAMIC 233 234 int dlclose(void *) __exported; 235 char *dlerror(void) __exported; 236 void *dlopen(const char *, int) __exported; 237 void *fdlopen(int, int) __exported; 238 void *dlsym(void *, const char *) __exported; 239 dlfunc_t dlfunc(void *, const char *) __exported; 240 void *dlvsym(void *, const char *, const char *) __exported; 241 int dladdr(const void *, Dl_info *) __exported; 242 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 243 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 244 int dlinfo(void *, int , void *) __exported; 245 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 246 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 247 int _rtld_get_stack_prot(void) __exported; 248 int _rtld_is_dlopened(void *) __exported; 249 void _rtld_error(const char *, ...) __exported; 250 251 /* Only here to fix -Wmissing-prototypes warnings */ 252 int __getosreldate(void); 253 void __pthread_cxa_finalize(struct dl_phdr_info *a); 254 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 255 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 256 257 258 int npagesizes; 259 static int osreldate; 260 size_t *pagesizes; 261 262 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 263 static int max_stack_flags; 264 265 /* 266 * Global declarations normally provided by crt1. The dynamic linker is 267 * not built with crt1, so we have to provide them ourselves. 268 */ 269 char *__progname; 270 char **environ; 271 272 /* 273 * Used to pass argc, argv to init functions. 274 */ 275 int main_argc; 276 char **main_argv; 277 278 /* 279 * Globals to control TLS allocation. 280 */ 281 size_t tls_last_offset; /* Static TLS offset of last module */ 282 size_t tls_last_size; /* Static TLS size of last module */ 283 size_t tls_static_space; /* Static TLS space allocated */ 284 static size_t tls_static_max_align; 285 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 286 int tls_max_index = 1; /* Largest module index allocated */ 287 288 static bool ld_library_path_rpath = false; 289 290 /* 291 * Globals for path names, and such 292 */ 293 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 294 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 295 const char *ld_path_rtld = _PATH_RTLD; 296 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 297 const char *ld_env_prefix = LD_; 298 299 static void (*rtld_exit_ptr)(void); 300 301 /* 302 * Fill in a DoneList with an allocation large enough to hold all of 303 * the currently-loaded objects. Keep this as a macro since it calls 304 * alloca and we want that to occur within the scope of the caller. 305 */ 306 #define donelist_init(dlp) \ 307 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 308 assert((dlp)->objs != NULL), \ 309 (dlp)->num_alloc = obj_count, \ 310 (dlp)->num_used = 0) 311 312 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 313 if (ld_utrace != NULL) \ 314 ld_utrace_log(e, h, mb, ms, r, n); \ 315 } while (0) 316 317 static void 318 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 319 int refcnt, const char *name) 320 { 321 struct utrace_rtld ut; 322 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 323 324 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 325 ut.event = event; 326 ut.handle = handle; 327 ut.mapbase = mapbase; 328 ut.mapsize = mapsize; 329 ut.refcnt = refcnt; 330 bzero(ut.name, sizeof(ut.name)); 331 if (name) 332 strlcpy(ut.name, name, sizeof(ut.name)); 333 utrace(&ut, sizeof(ut)); 334 } 335 336 #ifdef RTLD_VARIANT_ENV_NAMES 337 /* 338 * construct the env variable based on the type of binary that's 339 * running. 340 */ 341 static inline const char * 342 _LD(const char *var) 343 { 344 static char buffer[128]; 345 346 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 347 strlcat(buffer, var, sizeof(buffer)); 348 return (buffer); 349 } 350 #else 351 #define _LD(x) LD_ x 352 #endif 353 354 /* 355 * Main entry point for dynamic linking. The first argument is the 356 * stack pointer. The stack is expected to be laid out as described 357 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 358 * Specifically, the stack pointer points to a word containing 359 * ARGC. Following that in the stack is a null-terminated sequence 360 * of pointers to argument strings. Then comes a null-terminated 361 * sequence of pointers to environment strings. Finally, there is a 362 * sequence of "auxiliary vector" entries. 363 * 364 * The second argument points to a place to store the dynamic linker's 365 * exit procedure pointer and the third to a place to store the main 366 * program's object. 367 * 368 * The return value is the main program's entry point. 369 */ 370 func_ptr_type 371 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 372 { 373 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 374 Objlist_Entry *entry; 375 Obj_Entry *last_interposer, *obj, *preload_tail; 376 const Elf_Phdr *phdr; 377 Objlist initlist; 378 RtldLockState lockstate; 379 struct stat st; 380 Elf_Addr *argcp; 381 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 382 const char *argv0; 383 caddr_t imgentry; 384 char buf[MAXPATHLEN]; 385 int argc, fd, i, phnum, rtld_argc; 386 bool dir_enable, explicit_fd, search_in_path; 387 388 /* 389 * On entry, the dynamic linker itself has not been relocated yet. 390 * Be very careful not to reference any global data until after 391 * init_rtld has returned. It is OK to reference file-scope statics 392 * and string constants, and to call static and global functions. 393 */ 394 395 /* Find the auxiliary vector on the stack. */ 396 argcp = sp; 397 argc = *sp++; 398 argv = (char **) sp; 399 sp += argc + 1; /* Skip over arguments and NULL terminator */ 400 env = (char **) sp; 401 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 402 ; 403 aux = (Elf_Auxinfo *) sp; 404 405 /* Digest the auxiliary vector. */ 406 for (i = 0; i < AT_COUNT; i++) 407 aux_info[i] = NULL; 408 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 409 if (auxp->a_type < AT_COUNT) 410 aux_info[auxp->a_type] = auxp; 411 } 412 413 /* Initialize and relocate ourselves. */ 414 assert(aux_info[AT_BASE] != NULL); 415 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 416 417 __progname = obj_rtld.path; 418 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 419 environ = env; 420 main_argc = argc; 421 main_argv = argv; 422 423 trust = !issetugid(); 424 425 md_abi_variant_hook(aux_info); 426 427 fd = -1; 428 if (aux_info[AT_EXECFD] != NULL) { 429 fd = aux_info[AT_EXECFD]->a_un.a_val; 430 } else { 431 assert(aux_info[AT_PHDR] != NULL); 432 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 433 if (phdr == obj_rtld.phdr) { 434 if (!trust) { 435 _rtld_error("Tainted process refusing to run binary %s", 436 argv0); 437 rtld_die(); 438 } 439 dbg("opening main program in direct exec mode"); 440 if (argc >= 2) { 441 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 442 argv0 = argv[rtld_argc]; 443 explicit_fd = (fd != -1); 444 if (!explicit_fd) 445 fd = open_binary_fd(argv0, search_in_path); 446 if (fstat(fd, &st) == -1) { 447 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 448 explicit_fd ? "user-provided descriptor" : argv0, 449 rtld_strerror(errno)); 450 rtld_die(); 451 } 452 453 /* 454 * Rough emulation of the permission checks done by 455 * execve(2), only Unix DACs are checked, ACLs are 456 * ignored. Preserve the semantic of disabling owner 457 * to execute if owner x bit is cleared, even if 458 * others x bit is enabled. 459 * mmap(2) does not allow to mmap with PROT_EXEC if 460 * binary' file comes from noexec mount. We cannot 461 * set VV_TEXT on the binary. 462 */ 463 dir_enable = false; 464 if (st.st_uid == geteuid()) { 465 if ((st.st_mode & S_IXUSR) != 0) 466 dir_enable = true; 467 } else if (st.st_gid == getegid()) { 468 if ((st.st_mode & S_IXGRP) != 0) 469 dir_enable = true; 470 } else if ((st.st_mode & S_IXOTH) != 0) { 471 dir_enable = true; 472 } 473 if (!dir_enable) { 474 _rtld_error("No execute permission for binary %s", 475 argv0); 476 rtld_die(); 477 } 478 479 /* 480 * For direct exec mode, argv[0] is the interpreter 481 * name, we must remove it and shift arguments left 482 * before invoking binary main. Since stack layout 483 * places environment pointers and aux vectors right 484 * after the terminating NULL, we must shift 485 * environment and aux as well. 486 */ 487 main_argc = argc - rtld_argc; 488 for (i = 0; i <= main_argc; i++) 489 argv[i] = argv[i + rtld_argc]; 490 *argcp -= rtld_argc; 491 environ = env = envp = argv + main_argc + 1; 492 do { 493 *envp = *(envp + rtld_argc); 494 envp++; 495 } while (*envp != NULL); 496 aux = auxp = (Elf_Auxinfo *)envp; 497 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 498 for (;; auxp++, auxpf++) { 499 *auxp = *auxpf; 500 if (auxp->a_type == AT_NULL) 501 break; 502 } 503 } else { 504 _rtld_error("No binary"); 505 rtld_die(); 506 } 507 } 508 } 509 510 ld_bind_now = getenv(_LD("BIND_NOW")); 511 512 /* 513 * If the process is tainted, then we un-set the dangerous environment 514 * variables. The process will be marked as tainted until setuid(2) 515 * is called. If any child process calls setuid(2) we do not want any 516 * future processes to honor the potentially un-safe variables. 517 */ 518 if (!trust) { 519 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 520 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 521 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 522 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 523 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 524 _rtld_error("environment corrupt; aborting"); 525 rtld_die(); 526 } 527 } 528 ld_debug = getenv(_LD("DEBUG")); 529 if (ld_bind_now == NULL) 530 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 531 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 532 libmap_override = getenv(_LD("LIBMAP")); 533 ld_library_path = getenv(_LD("LIBRARY_PATH")); 534 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 535 ld_preload = getenv(_LD("PRELOAD")); 536 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 537 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 538 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 539 if (library_path_rpath != NULL) { 540 if (library_path_rpath[0] == 'y' || 541 library_path_rpath[0] == 'Y' || 542 library_path_rpath[0] == '1') 543 ld_library_path_rpath = true; 544 else 545 ld_library_path_rpath = false; 546 } 547 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 548 (ld_library_path != NULL) || (ld_preload != NULL) || 549 (ld_elf_hints_path != NULL) || ld_loadfltr; 550 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 551 ld_utrace = getenv(_LD("UTRACE")); 552 553 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 554 ld_elf_hints_path = ld_elf_hints_default; 555 556 if (ld_debug != NULL && *ld_debug != '\0') 557 debug = 1; 558 dbg("%s is initialized, base address = %p", __progname, 559 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 560 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 561 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 562 563 dbg("initializing thread locks"); 564 lockdflt_init(); 565 566 /* 567 * Load the main program, or process its program header if it is 568 * already loaded. 569 */ 570 if (fd != -1) { /* Load the main program. */ 571 dbg("loading main program"); 572 obj_main = map_object(fd, argv0, NULL); 573 close(fd); 574 if (obj_main == NULL) 575 rtld_die(); 576 max_stack_flags = obj_main->stack_flags; 577 } else { /* Main program already loaded. */ 578 dbg("processing main program's program header"); 579 assert(aux_info[AT_PHDR] != NULL); 580 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 581 assert(aux_info[AT_PHNUM] != NULL); 582 phnum = aux_info[AT_PHNUM]->a_un.a_val; 583 assert(aux_info[AT_PHENT] != NULL); 584 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 585 assert(aux_info[AT_ENTRY] != NULL); 586 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 587 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 588 rtld_die(); 589 } 590 591 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 592 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 593 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 594 if (kexecpath[0] == '/') 595 obj_main->path = kexecpath; 596 else if (getcwd(buf, sizeof(buf)) == NULL || 597 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 598 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 599 obj_main->path = xstrdup(argv0); 600 else 601 obj_main->path = xstrdup(buf); 602 } else { 603 dbg("No AT_EXECPATH or direct exec"); 604 obj_main->path = xstrdup(argv0); 605 } 606 dbg("obj_main path %s", obj_main->path); 607 obj_main->mainprog = true; 608 609 if (aux_info[AT_STACKPROT] != NULL && 610 aux_info[AT_STACKPROT]->a_un.a_val != 0) 611 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 612 613 #ifndef COMPAT_32BIT 614 /* 615 * Get the actual dynamic linker pathname from the executable if 616 * possible. (It should always be possible.) That ensures that 617 * gdb will find the right dynamic linker even if a non-standard 618 * one is being used. 619 */ 620 if (obj_main->interp != NULL && 621 strcmp(obj_main->interp, obj_rtld.path) != 0) { 622 free(obj_rtld.path); 623 obj_rtld.path = xstrdup(obj_main->interp); 624 __progname = obj_rtld.path; 625 } 626 #endif 627 628 digest_dynamic(obj_main, 0); 629 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 630 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 631 obj_main->dynsymcount); 632 633 linkmap_add(obj_main); 634 linkmap_add(&obj_rtld); 635 636 /* Link the main program into the list of objects. */ 637 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 638 obj_count++; 639 obj_loads++; 640 641 /* Initialize a fake symbol for resolving undefined weak references. */ 642 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 643 sym_zero.st_shndx = SHN_UNDEF; 644 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 645 646 if (!libmap_disable) 647 libmap_disable = (bool)lm_init(libmap_override); 648 649 dbg("loading LD_PRELOAD libraries"); 650 if (load_preload_objects() == -1) 651 rtld_die(); 652 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 653 654 dbg("loading needed objects"); 655 if (load_needed_objects(obj_main, 0) == -1) 656 rtld_die(); 657 658 /* Make a list of all objects loaded at startup. */ 659 last_interposer = obj_main; 660 TAILQ_FOREACH(obj, &obj_list, next) { 661 if (obj->marker) 662 continue; 663 if (obj->z_interpose && obj != obj_main) { 664 objlist_put_after(&list_main, last_interposer, obj); 665 last_interposer = obj; 666 } else { 667 objlist_push_tail(&list_main, obj); 668 } 669 obj->refcount++; 670 } 671 672 dbg("checking for required versions"); 673 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 674 rtld_die(); 675 676 if (ld_tracing) { /* We're done */ 677 trace_loaded_objects(obj_main); 678 exit(0); 679 } 680 681 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 682 dump_relocations(obj_main); 683 exit (0); 684 } 685 686 /* 687 * Processing tls relocations requires having the tls offsets 688 * initialized. Prepare offsets before starting initial 689 * relocation processing. 690 */ 691 dbg("initializing initial thread local storage offsets"); 692 STAILQ_FOREACH(entry, &list_main, link) { 693 /* 694 * Allocate all the initial objects out of the static TLS 695 * block even if they didn't ask for it. 696 */ 697 allocate_tls_offset(entry->obj); 698 } 699 700 if (relocate_objects(obj_main, 701 ld_bind_now != NULL && *ld_bind_now != '\0', 702 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 703 rtld_die(); 704 705 dbg("doing copy relocations"); 706 if (do_copy_relocations(obj_main) == -1) 707 rtld_die(); 708 709 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 710 dump_relocations(obj_main); 711 exit (0); 712 } 713 714 ifunc_init(aux); 715 716 /* 717 * Setup TLS for main thread. This must be done after the 718 * relocations are processed, since tls initialization section 719 * might be the subject for relocations. 720 */ 721 dbg("initializing initial thread local storage"); 722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 723 724 dbg("initializing key program variables"); 725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 726 set_program_var("environ", env); 727 set_program_var("__elf_aux_vector", aux); 728 729 /* Make a list of init functions to call. */ 730 objlist_init(&initlist); 731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 732 preload_tail, &initlist); 733 734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 735 736 map_stacks_exec(NULL); 737 738 if (!obj_main->crt_no_init) { 739 /* 740 * Make sure we don't call the main program's init and fini 741 * functions for binaries linked with old crt1 which calls 742 * _init itself. 743 */ 744 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 745 obj_main->preinit_array = obj_main->init_array = 746 obj_main->fini_array = (Elf_Addr)NULL; 747 } 748 749 /* 750 * Execute MD initializers required before we call the objects' 751 * init functions. 752 */ 753 pre_init(); 754 755 wlock_acquire(rtld_bind_lock, &lockstate); 756 757 dbg("resolving ifuncs"); 758 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 759 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 760 rtld_die(); 761 762 rtld_exit_ptr = rtld_exit; 763 if (obj_main->crt_no_init) 764 preinit_main(); 765 objlist_call_init(&initlist, &lockstate); 766 _r_debug_postinit(&obj_main->linkmap); 767 objlist_clear(&initlist); 768 dbg("loading filtees"); 769 TAILQ_FOREACH(obj, &obj_list, next) { 770 if (obj->marker) 771 continue; 772 if (ld_loadfltr || obj->z_loadfltr) 773 load_filtees(obj, 0, &lockstate); 774 } 775 776 dbg("enforcing main obj relro"); 777 if (obj_enforce_relro(obj_main) == -1) 778 rtld_die(); 779 780 lock_release(rtld_bind_lock, &lockstate); 781 782 dbg("transferring control to program entry point = %p", obj_main->entry); 783 784 /* Return the exit procedure and the program entry point. */ 785 *exit_proc = rtld_exit_ptr; 786 *objp = obj_main; 787 return (func_ptr_type) obj_main->entry; 788 } 789 790 void * 791 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 792 { 793 void *ptr; 794 Elf_Addr target; 795 796 ptr = (void *)make_function_pointer(def, obj); 797 target = call_ifunc_resolver(ptr); 798 return ((void *)target); 799 } 800 801 /* 802 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 803 * Changes to this function should be applied there as well. 804 */ 805 Elf_Addr 806 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 807 { 808 const Elf_Rel *rel; 809 const Elf_Sym *def; 810 const Obj_Entry *defobj; 811 Elf_Addr *where; 812 Elf_Addr target; 813 RtldLockState lockstate; 814 815 rlock_acquire(rtld_bind_lock, &lockstate); 816 if (sigsetjmp(lockstate.env, 0) != 0) 817 lock_upgrade(rtld_bind_lock, &lockstate); 818 if (obj->pltrel) 819 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 820 else 821 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 822 823 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 824 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 825 NULL, &lockstate); 826 if (def == NULL) 827 rtld_die(); 828 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 829 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 830 else 831 target = (Elf_Addr)(defobj->relocbase + def->st_value); 832 833 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 834 defobj->strtab + def->st_name, basename(obj->path), 835 (void *)target, basename(defobj->path)); 836 837 /* 838 * Write the new contents for the jmpslot. Note that depending on 839 * architecture, the value which we need to return back to the 840 * lazy binding trampoline may or may not be the target 841 * address. The value returned from reloc_jmpslot() is the value 842 * that the trampoline needs. 843 */ 844 target = reloc_jmpslot(where, target, defobj, obj, rel); 845 lock_release(rtld_bind_lock, &lockstate); 846 return target; 847 } 848 849 /* 850 * Error reporting function. Use it like printf. If formats the message 851 * into a buffer, and sets things up so that the next call to dlerror() 852 * will return the message. 853 */ 854 void 855 _rtld_error(const char *fmt, ...) 856 { 857 static char buf[512]; 858 va_list ap; 859 860 va_start(ap, fmt); 861 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 862 error_message = buf; 863 va_end(ap); 864 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 865 } 866 867 /* 868 * Return a dynamically-allocated copy of the current error message, if any. 869 */ 870 static char * 871 errmsg_save(void) 872 { 873 return error_message == NULL ? NULL : xstrdup(error_message); 874 } 875 876 /* 877 * Restore the current error message from a copy which was previously saved 878 * by errmsg_save(). The copy is freed. 879 */ 880 static void 881 errmsg_restore(char *saved_msg) 882 { 883 if (saved_msg == NULL) 884 error_message = NULL; 885 else { 886 _rtld_error("%s", saved_msg); 887 free(saved_msg); 888 } 889 } 890 891 static const char * 892 basename(const char *name) 893 { 894 const char *p = strrchr(name, '/'); 895 return p != NULL ? p + 1 : name; 896 } 897 898 static struct utsname uts; 899 900 static char * 901 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 902 const char *subst, bool may_free) 903 { 904 char *p, *p1, *res, *resp; 905 int subst_len, kw_len, subst_count, old_len, new_len; 906 907 kw_len = strlen(kw); 908 909 /* 910 * First, count the number of the keyword occurrences, to 911 * preallocate the final string. 912 */ 913 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 914 p1 = strstr(p, kw); 915 if (p1 == NULL) 916 break; 917 } 918 919 /* 920 * If the keyword is not found, just return. 921 * 922 * Return non-substituted string if resolution failed. We 923 * cannot do anything more reasonable, the failure mode of the 924 * caller is unresolved library anyway. 925 */ 926 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 927 return (may_free ? real : xstrdup(real)); 928 if (obj != NULL) 929 subst = obj->origin_path; 930 931 /* 932 * There is indeed something to substitute. Calculate the 933 * length of the resulting string, and allocate it. 934 */ 935 subst_len = strlen(subst); 936 old_len = strlen(real); 937 new_len = old_len + (subst_len - kw_len) * subst_count; 938 res = xmalloc(new_len + 1); 939 940 /* 941 * Now, execute the substitution loop. 942 */ 943 for (p = real, resp = res, *resp = '\0';;) { 944 p1 = strstr(p, kw); 945 if (p1 != NULL) { 946 /* Copy the prefix before keyword. */ 947 memcpy(resp, p, p1 - p); 948 resp += p1 - p; 949 /* Keyword replacement. */ 950 memcpy(resp, subst, subst_len); 951 resp += subst_len; 952 *resp = '\0'; 953 p = p1 + kw_len; 954 } else 955 break; 956 } 957 958 /* Copy to the end of string and finish. */ 959 strcat(resp, p); 960 if (may_free) 961 free(real); 962 return (res); 963 } 964 965 static char * 966 origin_subst(Obj_Entry *obj, const char *real) 967 { 968 char *res1, *res2, *res3, *res4; 969 970 if (obj == NULL || !trust) 971 return (xstrdup(real)); 972 if (uts.sysname[0] == '\0') { 973 if (uname(&uts) != 0) { 974 _rtld_error("utsname failed: %d", errno); 975 return (NULL); 976 } 977 } 978 /* __DECONST is safe here since without may_free real is unchanged */ 979 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 980 false); 981 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 982 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 983 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 984 return (res4); 985 } 986 987 void 988 rtld_die(void) 989 { 990 const char *msg = dlerror(); 991 992 if (msg == NULL) 993 msg = "Fatal error"; 994 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 995 rtld_fdputstr(STDERR_FILENO, msg); 996 rtld_fdputchar(STDERR_FILENO, '\n'); 997 _exit(1); 998 } 999 1000 /* 1001 * Process a shared object's DYNAMIC section, and save the important 1002 * information in its Obj_Entry structure. 1003 */ 1004 static void 1005 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1006 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1007 { 1008 const Elf_Dyn *dynp; 1009 Needed_Entry **needed_tail = &obj->needed; 1010 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1011 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1012 const Elf_Hashelt *hashtab; 1013 const Elf32_Word *hashval; 1014 Elf32_Word bkt, nmaskwords; 1015 int bloom_size32; 1016 int plttype = DT_REL; 1017 1018 *dyn_rpath = NULL; 1019 *dyn_soname = NULL; 1020 *dyn_runpath = NULL; 1021 1022 obj->bind_now = false; 1023 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1024 switch (dynp->d_tag) { 1025 1026 case DT_REL: 1027 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1028 break; 1029 1030 case DT_RELSZ: 1031 obj->relsize = dynp->d_un.d_val; 1032 break; 1033 1034 case DT_RELENT: 1035 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1036 break; 1037 1038 case DT_JMPREL: 1039 obj->pltrel = (const Elf_Rel *) 1040 (obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_PLTRELSZ: 1044 obj->pltrelsize = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_RELA: 1048 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1049 break; 1050 1051 case DT_RELASZ: 1052 obj->relasize = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_RELAENT: 1056 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1057 break; 1058 1059 case DT_PLTREL: 1060 plttype = dynp->d_un.d_val; 1061 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1062 break; 1063 1064 case DT_SYMTAB: 1065 obj->symtab = (const Elf_Sym *) 1066 (obj->relocbase + dynp->d_un.d_ptr); 1067 break; 1068 1069 case DT_SYMENT: 1070 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1071 break; 1072 1073 case DT_STRTAB: 1074 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1075 break; 1076 1077 case DT_STRSZ: 1078 obj->strsize = dynp->d_un.d_val; 1079 break; 1080 1081 case DT_VERNEED: 1082 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1083 dynp->d_un.d_val); 1084 break; 1085 1086 case DT_VERNEEDNUM: 1087 obj->verneednum = dynp->d_un.d_val; 1088 break; 1089 1090 case DT_VERDEF: 1091 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1092 dynp->d_un.d_val); 1093 break; 1094 1095 case DT_VERDEFNUM: 1096 obj->verdefnum = dynp->d_un.d_val; 1097 break; 1098 1099 case DT_VERSYM: 1100 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1101 dynp->d_un.d_val); 1102 break; 1103 1104 case DT_HASH: 1105 { 1106 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1107 dynp->d_un.d_ptr); 1108 obj->nbuckets = hashtab[0]; 1109 obj->nchains = hashtab[1]; 1110 obj->buckets = hashtab + 2; 1111 obj->chains = obj->buckets + obj->nbuckets; 1112 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1113 obj->buckets != NULL; 1114 } 1115 break; 1116 1117 case DT_GNU_HASH: 1118 { 1119 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1120 dynp->d_un.d_ptr); 1121 obj->nbuckets_gnu = hashtab[0]; 1122 obj->symndx_gnu = hashtab[1]; 1123 nmaskwords = hashtab[2]; 1124 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1125 obj->maskwords_bm_gnu = nmaskwords - 1; 1126 obj->shift2_gnu = hashtab[3]; 1127 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1128 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1129 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1130 obj->symndx_gnu; 1131 /* Number of bitmask words is required to be power of 2 */ 1132 obj->valid_hash_gnu = powerof2(nmaskwords) && 1133 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1134 } 1135 break; 1136 1137 case DT_NEEDED: 1138 if (!obj->rtld) { 1139 Needed_Entry *nep = NEW(Needed_Entry); 1140 nep->name = dynp->d_un.d_val; 1141 nep->obj = NULL; 1142 nep->next = NULL; 1143 1144 *needed_tail = nep; 1145 needed_tail = &nep->next; 1146 } 1147 break; 1148 1149 case DT_FILTER: 1150 if (!obj->rtld) { 1151 Needed_Entry *nep = NEW(Needed_Entry); 1152 nep->name = dynp->d_un.d_val; 1153 nep->obj = NULL; 1154 nep->next = NULL; 1155 1156 *needed_filtees_tail = nep; 1157 needed_filtees_tail = &nep->next; 1158 } 1159 break; 1160 1161 case DT_AUXILIARY: 1162 if (!obj->rtld) { 1163 Needed_Entry *nep = NEW(Needed_Entry); 1164 nep->name = dynp->d_un.d_val; 1165 nep->obj = NULL; 1166 nep->next = NULL; 1167 1168 *needed_aux_filtees_tail = nep; 1169 needed_aux_filtees_tail = &nep->next; 1170 } 1171 break; 1172 1173 case DT_PLTGOT: 1174 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1175 break; 1176 1177 case DT_TEXTREL: 1178 obj->textrel = true; 1179 break; 1180 1181 case DT_SYMBOLIC: 1182 obj->symbolic = true; 1183 break; 1184 1185 case DT_RPATH: 1186 /* 1187 * We have to wait until later to process this, because we 1188 * might not have gotten the address of the string table yet. 1189 */ 1190 *dyn_rpath = dynp; 1191 break; 1192 1193 case DT_SONAME: 1194 *dyn_soname = dynp; 1195 break; 1196 1197 case DT_RUNPATH: 1198 *dyn_runpath = dynp; 1199 break; 1200 1201 case DT_INIT: 1202 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1203 break; 1204 1205 case DT_PREINIT_ARRAY: 1206 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1207 break; 1208 1209 case DT_PREINIT_ARRAYSZ: 1210 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1211 break; 1212 1213 case DT_INIT_ARRAY: 1214 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1215 break; 1216 1217 case DT_INIT_ARRAYSZ: 1218 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1219 break; 1220 1221 case DT_FINI: 1222 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1223 break; 1224 1225 case DT_FINI_ARRAY: 1226 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1227 break; 1228 1229 case DT_FINI_ARRAYSZ: 1230 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1231 break; 1232 1233 /* 1234 * Don't process DT_DEBUG on MIPS as the dynamic section 1235 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1236 */ 1237 1238 #ifndef __mips__ 1239 case DT_DEBUG: 1240 if (!early) 1241 dbg("Filling in DT_DEBUG entry"); 1242 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1243 break; 1244 #endif 1245 1246 case DT_FLAGS: 1247 if (dynp->d_un.d_val & DF_ORIGIN) 1248 obj->z_origin = true; 1249 if (dynp->d_un.d_val & DF_SYMBOLIC) 1250 obj->symbolic = true; 1251 if (dynp->d_un.d_val & DF_TEXTREL) 1252 obj->textrel = true; 1253 if (dynp->d_un.d_val & DF_BIND_NOW) 1254 obj->bind_now = true; 1255 if (dynp->d_un.d_val & DF_STATIC_TLS) 1256 obj->static_tls = true; 1257 break; 1258 #ifdef __mips__ 1259 case DT_MIPS_LOCAL_GOTNO: 1260 obj->local_gotno = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_SYMTABNO: 1264 obj->symtabno = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_MIPS_GOTSYM: 1268 obj->gotsym = dynp->d_un.d_val; 1269 break; 1270 1271 case DT_MIPS_RLD_MAP: 1272 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1273 break; 1274 1275 case DT_MIPS_RLD_MAP_REL: 1276 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1277 // section relative to the address of the tag itself. 1278 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1279 (Elf_Addr) &r_debug; 1280 break; 1281 1282 case DT_MIPS_PLTGOT: 1283 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1284 dynp->d_un.d_ptr); 1285 break; 1286 1287 #endif 1288 1289 #ifdef __powerpc64__ 1290 case DT_PPC64_GLINK: 1291 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1292 break; 1293 #endif 1294 1295 case DT_FLAGS_1: 1296 if (dynp->d_un.d_val & DF_1_NOOPEN) 1297 obj->z_noopen = true; 1298 if (dynp->d_un.d_val & DF_1_ORIGIN) 1299 obj->z_origin = true; 1300 if (dynp->d_un.d_val & DF_1_GLOBAL) 1301 obj->z_global = true; 1302 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1303 obj->bind_now = true; 1304 if (dynp->d_un.d_val & DF_1_NODELETE) 1305 obj->z_nodelete = true; 1306 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1307 obj->z_loadfltr = true; 1308 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1309 obj->z_interpose = true; 1310 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1311 obj->z_nodeflib = true; 1312 break; 1313 1314 default: 1315 if (!early) { 1316 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1317 (long)dynp->d_tag); 1318 } 1319 break; 1320 } 1321 } 1322 1323 obj->traced = false; 1324 1325 if (plttype == DT_RELA) { 1326 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1327 obj->pltrel = NULL; 1328 obj->pltrelasize = obj->pltrelsize; 1329 obj->pltrelsize = 0; 1330 } 1331 1332 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1333 if (obj->valid_hash_sysv) 1334 obj->dynsymcount = obj->nchains; 1335 else if (obj->valid_hash_gnu) { 1336 obj->dynsymcount = 0; 1337 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1338 if (obj->buckets_gnu[bkt] == 0) 1339 continue; 1340 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1341 do 1342 obj->dynsymcount++; 1343 while ((*hashval++ & 1u) == 0); 1344 } 1345 obj->dynsymcount += obj->symndx_gnu; 1346 } 1347 } 1348 1349 static bool 1350 obj_resolve_origin(Obj_Entry *obj) 1351 { 1352 1353 if (obj->origin_path != NULL) 1354 return (true); 1355 obj->origin_path = xmalloc(PATH_MAX); 1356 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1357 } 1358 1359 static void 1360 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1361 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1362 { 1363 1364 if (obj->z_origin && !obj_resolve_origin(obj)) 1365 rtld_die(); 1366 1367 if (dyn_runpath != NULL) { 1368 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1369 obj->runpath = origin_subst(obj, obj->runpath); 1370 } else if (dyn_rpath != NULL) { 1371 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1372 obj->rpath = origin_subst(obj, obj->rpath); 1373 } 1374 if (dyn_soname != NULL) 1375 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1376 } 1377 1378 static void 1379 digest_dynamic(Obj_Entry *obj, int early) 1380 { 1381 const Elf_Dyn *dyn_rpath; 1382 const Elf_Dyn *dyn_soname; 1383 const Elf_Dyn *dyn_runpath; 1384 1385 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1386 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1387 } 1388 1389 /* 1390 * Process a shared object's program header. This is used only for the 1391 * main program, when the kernel has already loaded the main program 1392 * into memory before calling the dynamic linker. It creates and 1393 * returns an Obj_Entry structure. 1394 */ 1395 static Obj_Entry * 1396 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1397 { 1398 Obj_Entry *obj; 1399 const Elf_Phdr *phlimit = phdr + phnum; 1400 const Elf_Phdr *ph; 1401 Elf_Addr note_start, note_end; 1402 int nsegs = 0; 1403 1404 obj = obj_new(); 1405 for (ph = phdr; ph < phlimit; ph++) { 1406 if (ph->p_type != PT_PHDR) 1407 continue; 1408 1409 obj->phdr = phdr; 1410 obj->phsize = ph->p_memsz; 1411 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1412 break; 1413 } 1414 1415 obj->stack_flags = PF_X | PF_R | PF_W; 1416 1417 for (ph = phdr; ph < phlimit; ph++) { 1418 switch (ph->p_type) { 1419 1420 case PT_INTERP: 1421 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1422 break; 1423 1424 case PT_LOAD: 1425 if (nsegs == 0) { /* First load segment */ 1426 obj->vaddrbase = trunc_page(ph->p_vaddr); 1427 obj->mapbase = obj->vaddrbase + obj->relocbase; 1428 } else { /* Last load segment */ 1429 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1430 obj->vaddrbase; 1431 } 1432 nsegs++; 1433 break; 1434 1435 case PT_DYNAMIC: 1436 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1437 break; 1438 1439 case PT_TLS: 1440 obj->tlsindex = 1; 1441 obj->tlssize = ph->p_memsz; 1442 obj->tlsalign = ph->p_align; 1443 obj->tlsinitsize = ph->p_filesz; 1444 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1445 break; 1446 1447 case PT_GNU_STACK: 1448 obj->stack_flags = ph->p_flags; 1449 break; 1450 1451 case PT_GNU_RELRO: 1452 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1453 obj->relro_size = round_page(ph->p_memsz); 1454 break; 1455 1456 case PT_NOTE: 1457 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1458 note_end = note_start + ph->p_filesz; 1459 digest_notes(obj, note_start, note_end); 1460 break; 1461 } 1462 } 1463 if (nsegs < 1) { 1464 _rtld_error("%s: too few PT_LOAD segments", path); 1465 return NULL; 1466 } 1467 1468 obj->entry = entry; 1469 return obj; 1470 } 1471 1472 void 1473 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1474 { 1475 const Elf_Note *note; 1476 const char *note_name; 1477 uintptr_t p; 1478 1479 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1480 note = (const Elf_Note *)((const char *)(note + 1) + 1481 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1482 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1483 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1484 note->n_descsz != sizeof(int32_t)) 1485 continue; 1486 if (note->n_type != NT_FREEBSD_ABI_TAG && 1487 note->n_type != NT_FREEBSD_FEATURE_CTL && 1488 note->n_type != NT_FREEBSD_NOINIT_TAG) 1489 continue; 1490 note_name = (const char *)(note + 1); 1491 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1492 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1493 continue; 1494 switch (note->n_type) { 1495 case NT_FREEBSD_ABI_TAG: 1496 /* FreeBSD osrel note */ 1497 p = (uintptr_t)(note + 1); 1498 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1499 obj->osrel = *(const int32_t *)(p); 1500 dbg("note osrel %d", obj->osrel); 1501 break; 1502 case NT_FREEBSD_FEATURE_CTL: 1503 /* FreeBSD ABI feature control note */ 1504 p = (uintptr_t)(note + 1); 1505 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1506 obj->fctl0 = *(const uint32_t *)(p); 1507 dbg("note fctl0 %#x", obj->fctl0); 1508 break; 1509 case NT_FREEBSD_NOINIT_TAG: 1510 /* FreeBSD 'crt does not call init' note */ 1511 obj->crt_no_init = true; 1512 dbg("note crt_no_init"); 1513 break; 1514 } 1515 } 1516 } 1517 1518 static Obj_Entry * 1519 dlcheck(void *handle) 1520 { 1521 Obj_Entry *obj; 1522 1523 TAILQ_FOREACH(obj, &obj_list, next) { 1524 if (obj == (Obj_Entry *) handle) 1525 break; 1526 } 1527 1528 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1529 _rtld_error("Invalid shared object handle %p", handle); 1530 return NULL; 1531 } 1532 return obj; 1533 } 1534 1535 /* 1536 * If the given object is already in the donelist, return true. Otherwise 1537 * add the object to the list and return false. 1538 */ 1539 static bool 1540 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1541 { 1542 unsigned int i; 1543 1544 for (i = 0; i < dlp->num_used; i++) 1545 if (dlp->objs[i] == obj) 1546 return true; 1547 /* 1548 * Our donelist allocation should always be sufficient. But if 1549 * our threads locking isn't working properly, more shared objects 1550 * could have been loaded since we allocated the list. That should 1551 * never happen, but we'll handle it properly just in case it does. 1552 */ 1553 if (dlp->num_used < dlp->num_alloc) 1554 dlp->objs[dlp->num_used++] = obj; 1555 return false; 1556 } 1557 1558 /* 1559 * Hash function for symbol table lookup. Don't even think about changing 1560 * this. It is specified by the System V ABI. 1561 */ 1562 unsigned long 1563 elf_hash(const char *name) 1564 { 1565 const unsigned char *p = (const unsigned char *) name; 1566 unsigned long h = 0; 1567 unsigned long g; 1568 1569 while (*p != '\0') { 1570 h = (h << 4) + *p++; 1571 if ((g = h & 0xf0000000) != 0) 1572 h ^= g >> 24; 1573 h &= ~g; 1574 } 1575 return h; 1576 } 1577 1578 /* 1579 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1580 * unsigned in case it's implemented with a wider type. 1581 */ 1582 static uint32_t 1583 gnu_hash(const char *s) 1584 { 1585 uint32_t h; 1586 unsigned char c; 1587 1588 h = 5381; 1589 for (c = *s; c != '\0'; c = *++s) 1590 h = h * 33 + c; 1591 return (h & 0xffffffff); 1592 } 1593 1594 1595 /* 1596 * Find the library with the given name, and return its full pathname. 1597 * The returned string is dynamically allocated. Generates an error 1598 * message and returns NULL if the library cannot be found. 1599 * 1600 * If the second argument is non-NULL, then it refers to an already- 1601 * loaded shared object, whose library search path will be searched. 1602 * 1603 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1604 * descriptor (which is close-on-exec) will be passed out via the third 1605 * argument. 1606 * 1607 * The search order is: 1608 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1609 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1610 * LD_LIBRARY_PATH 1611 * DT_RUNPATH in the referencing file 1612 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1613 * from list) 1614 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1615 * 1616 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1617 */ 1618 static char * 1619 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1620 { 1621 char *pathname, *refobj_path; 1622 const char *name; 1623 bool nodeflib, objgiven; 1624 1625 objgiven = refobj != NULL; 1626 1627 if (libmap_disable || !objgiven || 1628 (name = lm_find(refobj->path, xname)) == NULL) 1629 name = xname; 1630 1631 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1632 if (name[0] != '/' && !trust) { 1633 _rtld_error("Absolute pathname required " 1634 "for shared object \"%s\"", name); 1635 return (NULL); 1636 } 1637 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1638 __DECONST(char *, name))); 1639 } 1640 1641 dbg(" Searching for \"%s\"", name); 1642 refobj_path = objgiven ? refobj->path : NULL; 1643 1644 /* 1645 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1646 * back to pre-conforming behaviour if user requested so with 1647 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1648 * nodeflib. 1649 */ 1650 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1651 pathname = search_library_path(name, ld_library_path, 1652 refobj_path, fdp); 1653 if (pathname != NULL) 1654 return (pathname); 1655 if (refobj != NULL) { 1656 pathname = search_library_path(name, refobj->rpath, 1657 refobj_path, fdp); 1658 if (pathname != NULL) 1659 return (pathname); 1660 } 1661 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1662 if (pathname != NULL) 1663 return (pathname); 1664 pathname = search_library_path(name, gethints(false), 1665 refobj_path, fdp); 1666 if (pathname != NULL) 1667 return (pathname); 1668 pathname = search_library_path(name, ld_standard_library_path, 1669 refobj_path, fdp); 1670 if (pathname != NULL) 1671 return (pathname); 1672 } else { 1673 nodeflib = objgiven ? refobj->z_nodeflib : false; 1674 if (objgiven) { 1675 pathname = search_library_path(name, refobj->rpath, 1676 refobj->path, fdp); 1677 if (pathname != NULL) 1678 return (pathname); 1679 } 1680 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1681 pathname = search_library_path(name, obj_main->rpath, 1682 refobj_path, fdp); 1683 if (pathname != NULL) 1684 return (pathname); 1685 } 1686 pathname = search_library_path(name, ld_library_path, 1687 refobj_path, fdp); 1688 if (pathname != NULL) 1689 return (pathname); 1690 if (objgiven) { 1691 pathname = search_library_path(name, refobj->runpath, 1692 refobj_path, fdp); 1693 if (pathname != NULL) 1694 return (pathname); 1695 } 1696 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1697 if (pathname != NULL) 1698 return (pathname); 1699 pathname = search_library_path(name, gethints(nodeflib), 1700 refobj_path, fdp); 1701 if (pathname != NULL) 1702 return (pathname); 1703 if (objgiven && !nodeflib) { 1704 pathname = search_library_path(name, 1705 ld_standard_library_path, refobj_path, fdp); 1706 if (pathname != NULL) 1707 return (pathname); 1708 } 1709 } 1710 1711 if (objgiven && refobj->path != NULL) { 1712 _rtld_error("Shared object \"%s\" not found, " 1713 "required by \"%s\"", name, basename(refobj->path)); 1714 } else { 1715 _rtld_error("Shared object \"%s\" not found", name); 1716 } 1717 return (NULL); 1718 } 1719 1720 /* 1721 * Given a symbol number in a referencing object, find the corresponding 1722 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1723 * no definition was found. Returns a pointer to the Obj_Entry of the 1724 * defining object via the reference parameter DEFOBJ_OUT. 1725 */ 1726 const Elf_Sym * 1727 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1728 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1729 RtldLockState *lockstate) 1730 { 1731 const Elf_Sym *ref; 1732 const Elf_Sym *def; 1733 const Obj_Entry *defobj; 1734 const Ver_Entry *ve; 1735 SymLook req; 1736 const char *name; 1737 int res; 1738 1739 /* 1740 * If we have already found this symbol, get the information from 1741 * the cache. 1742 */ 1743 if (symnum >= refobj->dynsymcount) 1744 return NULL; /* Bad object */ 1745 if (cache != NULL && cache[symnum].sym != NULL) { 1746 *defobj_out = cache[symnum].obj; 1747 return cache[symnum].sym; 1748 } 1749 1750 ref = refobj->symtab + symnum; 1751 name = refobj->strtab + ref->st_name; 1752 def = NULL; 1753 defobj = NULL; 1754 ve = NULL; 1755 1756 /* 1757 * We don't have to do a full scale lookup if the symbol is local. 1758 * We know it will bind to the instance in this load module; to 1759 * which we already have a pointer (ie ref). By not doing a lookup, 1760 * we not only improve performance, but it also avoids unresolvable 1761 * symbols when local symbols are not in the hash table. This has 1762 * been seen with the ia64 toolchain. 1763 */ 1764 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1765 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1766 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1767 symnum); 1768 } 1769 symlook_init(&req, name); 1770 req.flags = flags; 1771 ve = req.ventry = fetch_ventry(refobj, symnum); 1772 req.lockstate = lockstate; 1773 res = symlook_default(&req, refobj); 1774 if (res == 0) { 1775 def = req.sym_out; 1776 defobj = req.defobj_out; 1777 } 1778 } else { 1779 def = ref; 1780 defobj = refobj; 1781 } 1782 1783 /* 1784 * If we found no definition and the reference is weak, treat the 1785 * symbol as having the value zero. 1786 */ 1787 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1788 def = &sym_zero; 1789 defobj = obj_main; 1790 } 1791 1792 if (def != NULL) { 1793 *defobj_out = defobj; 1794 /* Record the information in the cache to avoid subsequent lookups. */ 1795 if (cache != NULL) { 1796 cache[symnum].sym = def; 1797 cache[symnum].obj = defobj; 1798 } 1799 } else { 1800 if (refobj != &obj_rtld) 1801 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1802 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1803 } 1804 return def; 1805 } 1806 1807 /* 1808 * Return the search path from the ldconfig hints file, reading it if 1809 * necessary. If nostdlib is true, then the default search paths are 1810 * not added to result. 1811 * 1812 * Returns NULL if there are problems with the hints file, 1813 * or if the search path there is empty. 1814 */ 1815 static const char * 1816 gethints(bool nostdlib) 1817 { 1818 static char *filtered_path; 1819 static const char *hints; 1820 static struct elfhints_hdr hdr; 1821 struct fill_search_info_args sargs, hargs; 1822 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1823 struct dl_serpath *SLPpath, *hintpath; 1824 char *p; 1825 struct stat hint_stat; 1826 unsigned int SLPndx, hintndx, fndx, fcount; 1827 int fd; 1828 size_t flen; 1829 uint32_t dl; 1830 bool skip; 1831 1832 /* First call, read the hints file */ 1833 if (hints == NULL) { 1834 /* Keep from trying again in case the hints file is bad. */ 1835 hints = ""; 1836 1837 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1838 return (NULL); 1839 1840 /* 1841 * Check of hdr.dirlistlen value against type limit 1842 * intends to pacify static analyzers. Further 1843 * paranoia leads to checks that dirlist is fully 1844 * contained in the file range. 1845 */ 1846 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1847 hdr.magic != ELFHINTS_MAGIC || 1848 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1849 fstat(fd, &hint_stat) == -1) { 1850 cleanup1: 1851 close(fd); 1852 hdr.dirlistlen = 0; 1853 return (NULL); 1854 } 1855 dl = hdr.strtab; 1856 if (dl + hdr.dirlist < dl) 1857 goto cleanup1; 1858 dl += hdr.dirlist; 1859 if (dl + hdr.dirlistlen < dl) 1860 goto cleanup1; 1861 dl += hdr.dirlistlen; 1862 if (dl > hint_stat.st_size) 1863 goto cleanup1; 1864 p = xmalloc(hdr.dirlistlen + 1); 1865 if (pread(fd, p, hdr.dirlistlen + 1, 1866 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1867 p[hdr.dirlistlen] != '\0') { 1868 free(p); 1869 goto cleanup1; 1870 } 1871 hints = p; 1872 close(fd); 1873 } 1874 1875 /* 1876 * If caller agreed to receive list which includes the default 1877 * paths, we are done. Otherwise, if we still did not 1878 * calculated filtered result, do it now. 1879 */ 1880 if (!nostdlib) 1881 return (hints[0] != '\0' ? hints : NULL); 1882 if (filtered_path != NULL) 1883 goto filt_ret; 1884 1885 /* 1886 * Obtain the list of all configured search paths, and the 1887 * list of the default paths. 1888 * 1889 * First estimate the size of the results. 1890 */ 1891 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1892 smeta.dls_cnt = 0; 1893 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1894 hmeta.dls_cnt = 0; 1895 1896 sargs.request = RTLD_DI_SERINFOSIZE; 1897 sargs.serinfo = &smeta; 1898 hargs.request = RTLD_DI_SERINFOSIZE; 1899 hargs.serinfo = &hmeta; 1900 1901 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1902 &sargs); 1903 path_enumerate(hints, fill_search_info, NULL, &hargs); 1904 1905 SLPinfo = xmalloc(smeta.dls_size); 1906 hintinfo = xmalloc(hmeta.dls_size); 1907 1908 /* 1909 * Next fetch both sets of paths. 1910 */ 1911 sargs.request = RTLD_DI_SERINFO; 1912 sargs.serinfo = SLPinfo; 1913 sargs.serpath = &SLPinfo->dls_serpath[0]; 1914 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1915 1916 hargs.request = RTLD_DI_SERINFO; 1917 hargs.serinfo = hintinfo; 1918 hargs.serpath = &hintinfo->dls_serpath[0]; 1919 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1920 1921 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1922 &sargs); 1923 path_enumerate(hints, fill_search_info, NULL, &hargs); 1924 1925 /* 1926 * Now calculate the difference between two sets, by excluding 1927 * standard paths from the full set. 1928 */ 1929 fndx = 0; 1930 fcount = 0; 1931 filtered_path = xmalloc(hdr.dirlistlen + 1); 1932 hintpath = &hintinfo->dls_serpath[0]; 1933 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1934 skip = false; 1935 SLPpath = &SLPinfo->dls_serpath[0]; 1936 /* 1937 * Check each standard path against current. 1938 */ 1939 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1940 /* matched, skip the path */ 1941 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1942 skip = true; 1943 break; 1944 } 1945 } 1946 if (skip) 1947 continue; 1948 /* 1949 * Not matched against any standard path, add the path 1950 * to result. Separate consequtive paths with ':'. 1951 */ 1952 if (fcount > 0) { 1953 filtered_path[fndx] = ':'; 1954 fndx++; 1955 } 1956 fcount++; 1957 flen = strlen(hintpath->dls_name); 1958 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1959 fndx += flen; 1960 } 1961 filtered_path[fndx] = '\0'; 1962 1963 free(SLPinfo); 1964 free(hintinfo); 1965 1966 filt_ret: 1967 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1968 } 1969 1970 static void 1971 init_dag(Obj_Entry *root) 1972 { 1973 const Needed_Entry *needed; 1974 const Objlist_Entry *elm; 1975 DoneList donelist; 1976 1977 if (root->dag_inited) 1978 return; 1979 donelist_init(&donelist); 1980 1981 /* Root object belongs to own DAG. */ 1982 objlist_push_tail(&root->dldags, root); 1983 objlist_push_tail(&root->dagmembers, root); 1984 donelist_check(&donelist, root); 1985 1986 /* 1987 * Add dependencies of root object to DAG in breadth order 1988 * by exploiting the fact that each new object get added 1989 * to the tail of the dagmembers list. 1990 */ 1991 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1992 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1993 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1994 continue; 1995 objlist_push_tail(&needed->obj->dldags, root); 1996 objlist_push_tail(&root->dagmembers, needed->obj); 1997 } 1998 } 1999 root->dag_inited = true; 2000 } 2001 2002 static void 2003 init_marker(Obj_Entry *marker) 2004 { 2005 2006 bzero(marker, sizeof(*marker)); 2007 marker->marker = true; 2008 } 2009 2010 Obj_Entry * 2011 globallist_curr(const Obj_Entry *obj) 2012 { 2013 2014 for (;;) { 2015 if (obj == NULL) 2016 return (NULL); 2017 if (!obj->marker) 2018 return (__DECONST(Obj_Entry *, obj)); 2019 obj = TAILQ_PREV(obj, obj_entry_q, next); 2020 } 2021 } 2022 2023 Obj_Entry * 2024 globallist_next(const Obj_Entry *obj) 2025 { 2026 2027 for (;;) { 2028 obj = TAILQ_NEXT(obj, next); 2029 if (obj == NULL) 2030 return (NULL); 2031 if (!obj->marker) 2032 return (__DECONST(Obj_Entry *, obj)); 2033 } 2034 } 2035 2036 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2037 static void 2038 hold_object(Obj_Entry *obj) 2039 { 2040 2041 obj->holdcount++; 2042 } 2043 2044 static void 2045 unhold_object(Obj_Entry *obj) 2046 { 2047 2048 assert(obj->holdcount > 0); 2049 if (--obj->holdcount == 0 && obj->unholdfree) 2050 release_object(obj); 2051 } 2052 2053 static void 2054 process_z(Obj_Entry *root) 2055 { 2056 const Objlist_Entry *elm; 2057 Obj_Entry *obj; 2058 2059 /* 2060 * Walk over object DAG and process every dependent object 2061 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2062 * to grow their own DAG. 2063 * 2064 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2065 * symlook_global() to work. 2066 * 2067 * For DF_1_NODELETE, the DAG should have its reference upped. 2068 */ 2069 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2070 obj = elm->obj; 2071 if (obj == NULL) 2072 continue; 2073 if (obj->z_nodelete && !obj->ref_nodel) { 2074 dbg("obj %s -z nodelete", obj->path); 2075 init_dag(obj); 2076 ref_dag(obj); 2077 obj->ref_nodel = true; 2078 } 2079 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2080 dbg("obj %s -z global", obj->path); 2081 objlist_push_tail(&list_global, obj); 2082 init_dag(obj); 2083 } 2084 } 2085 } 2086 /* 2087 * Initialize the dynamic linker. The argument is the address at which 2088 * the dynamic linker has been mapped into memory. The primary task of 2089 * this function is to relocate the dynamic linker. 2090 */ 2091 static void 2092 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2093 { 2094 Obj_Entry objtmp; /* Temporary rtld object */ 2095 const Elf_Ehdr *ehdr; 2096 const Elf_Dyn *dyn_rpath; 2097 const Elf_Dyn *dyn_soname; 2098 const Elf_Dyn *dyn_runpath; 2099 2100 #ifdef RTLD_INIT_PAGESIZES_EARLY 2101 /* The page size is required by the dynamic memory allocator. */ 2102 init_pagesizes(aux_info); 2103 #endif 2104 2105 /* 2106 * Conjure up an Obj_Entry structure for the dynamic linker. 2107 * 2108 * The "path" member can't be initialized yet because string constants 2109 * cannot yet be accessed. Below we will set it correctly. 2110 */ 2111 memset(&objtmp, 0, sizeof(objtmp)); 2112 objtmp.path = NULL; 2113 objtmp.rtld = true; 2114 objtmp.mapbase = mapbase; 2115 #ifdef PIC 2116 objtmp.relocbase = mapbase; 2117 #endif 2118 2119 objtmp.dynamic = rtld_dynamic(&objtmp); 2120 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2121 assert(objtmp.needed == NULL); 2122 #if !defined(__mips__) 2123 /* MIPS has a bogus DT_TEXTREL. */ 2124 assert(!objtmp.textrel); 2125 #endif 2126 /* 2127 * Temporarily put the dynamic linker entry into the object list, so 2128 * that symbols can be found. 2129 */ 2130 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2131 2132 ehdr = (Elf_Ehdr *)mapbase; 2133 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2134 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2135 2136 /* Initialize the object list. */ 2137 TAILQ_INIT(&obj_list); 2138 2139 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2140 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2141 2142 #ifndef RTLD_INIT_PAGESIZES_EARLY 2143 /* The page size is required by the dynamic memory allocator. */ 2144 init_pagesizes(aux_info); 2145 #endif 2146 2147 if (aux_info[AT_OSRELDATE] != NULL) 2148 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2149 2150 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2151 2152 /* Replace the path with a dynamically allocated copy. */ 2153 obj_rtld.path = xstrdup(ld_path_rtld); 2154 2155 r_debug.r_brk = r_debug_state; 2156 r_debug.r_state = RT_CONSISTENT; 2157 } 2158 2159 /* 2160 * Retrieve the array of supported page sizes. The kernel provides the page 2161 * sizes in increasing order. 2162 */ 2163 static void 2164 init_pagesizes(Elf_Auxinfo **aux_info) 2165 { 2166 static size_t psa[MAXPAGESIZES]; 2167 int mib[2]; 2168 size_t len, size; 2169 2170 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2171 NULL) { 2172 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2173 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2174 } else { 2175 len = 2; 2176 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2177 size = sizeof(psa); 2178 else { 2179 /* As a fallback, retrieve the base page size. */ 2180 size = sizeof(psa[0]); 2181 if (aux_info[AT_PAGESZ] != NULL) { 2182 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2183 goto psa_filled; 2184 } else { 2185 mib[0] = CTL_HW; 2186 mib[1] = HW_PAGESIZE; 2187 len = 2; 2188 } 2189 } 2190 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2191 _rtld_error("sysctl for hw.pagesize(s) failed"); 2192 rtld_die(); 2193 } 2194 psa_filled: 2195 pagesizes = psa; 2196 } 2197 npagesizes = size / sizeof(pagesizes[0]); 2198 /* Discard any invalid entries at the end of the array. */ 2199 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2200 npagesizes--; 2201 } 2202 2203 /* 2204 * Add the init functions from a needed object list (and its recursive 2205 * needed objects) to "list". This is not used directly; it is a helper 2206 * function for initlist_add_objects(). The write lock must be held 2207 * when this function is called. 2208 */ 2209 static void 2210 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2211 { 2212 /* Recursively process the successor needed objects. */ 2213 if (needed->next != NULL) 2214 initlist_add_neededs(needed->next, list); 2215 2216 /* Process the current needed object. */ 2217 if (needed->obj != NULL) 2218 initlist_add_objects(needed->obj, needed->obj, list); 2219 } 2220 2221 /* 2222 * Scan all of the DAGs rooted in the range of objects from "obj" to 2223 * "tail" and add their init functions to "list". This recurses over 2224 * the DAGs and ensure the proper init ordering such that each object's 2225 * needed libraries are initialized before the object itself. At the 2226 * same time, this function adds the objects to the global finalization 2227 * list "list_fini" in the opposite order. The write lock must be 2228 * held when this function is called. 2229 */ 2230 static void 2231 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2232 { 2233 Obj_Entry *nobj; 2234 2235 if (obj->init_scanned || obj->init_done) 2236 return; 2237 obj->init_scanned = true; 2238 2239 /* Recursively process the successor objects. */ 2240 nobj = globallist_next(obj); 2241 if (nobj != NULL && obj != tail) 2242 initlist_add_objects(nobj, tail, list); 2243 2244 /* Recursively process the needed objects. */ 2245 if (obj->needed != NULL) 2246 initlist_add_neededs(obj->needed, list); 2247 if (obj->needed_filtees != NULL) 2248 initlist_add_neededs(obj->needed_filtees, list); 2249 if (obj->needed_aux_filtees != NULL) 2250 initlist_add_neededs(obj->needed_aux_filtees, list); 2251 2252 /* Add the object to the init list. */ 2253 objlist_push_tail(list, obj); 2254 2255 /* Add the object to the global fini list in the reverse order. */ 2256 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2257 && !obj->on_fini_list) { 2258 objlist_push_head(&list_fini, obj); 2259 obj->on_fini_list = true; 2260 } 2261 } 2262 2263 #ifndef FPTR_TARGET 2264 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2265 #endif 2266 2267 static void 2268 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2269 { 2270 Needed_Entry *needed, *needed1; 2271 2272 for (needed = n; needed != NULL; needed = needed->next) { 2273 if (needed->obj != NULL) { 2274 dlclose_locked(needed->obj, lockstate); 2275 needed->obj = NULL; 2276 } 2277 } 2278 for (needed = n; needed != NULL; needed = needed1) { 2279 needed1 = needed->next; 2280 free(needed); 2281 } 2282 } 2283 2284 static void 2285 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2286 { 2287 2288 free_needed_filtees(obj->needed_filtees, lockstate); 2289 obj->needed_filtees = NULL; 2290 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2291 obj->needed_aux_filtees = NULL; 2292 obj->filtees_loaded = false; 2293 } 2294 2295 static void 2296 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2297 RtldLockState *lockstate) 2298 { 2299 2300 for (; needed != NULL; needed = needed->next) { 2301 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2302 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2303 RTLD_LOCAL, lockstate); 2304 } 2305 } 2306 2307 static void 2308 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2309 { 2310 2311 lock_restart_for_upgrade(lockstate); 2312 if (!obj->filtees_loaded) { 2313 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2314 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2315 obj->filtees_loaded = true; 2316 } 2317 } 2318 2319 static int 2320 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2321 { 2322 Obj_Entry *obj1; 2323 2324 for (; needed != NULL; needed = needed->next) { 2325 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2326 flags & ~RTLD_LO_NOLOAD); 2327 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2328 return (-1); 2329 } 2330 return (0); 2331 } 2332 2333 /* 2334 * Given a shared object, traverse its list of needed objects, and load 2335 * each of them. Returns 0 on success. Generates an error message and 2336 * returns -1 on failure. 2337 */ 2338 static int 2339 load_needed_objects(Obj_Entry *first, int flags) 2340 { 2341 Obj_Entry *obj; 2342 2343 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2344 if (obj->marker) 2345 continue; 2346 if (process_needed(obj, obj->needed, flags) == -1) 2347 return (-1); 2348 } 2349 return (0); 2350 } 2351 2352 static int 2353 load_preload_objects(void) 2354 { 2355 char *p = ld_preload; 2356 Obj_Entry *obj; 2357 static const char delim[] = " \t:;"; 2358 2359 if (p == NULL) 2360 return 0; 2361 2362 p += strspn(p, delim); 2363 while (*p != '\0') { 2364 size_t len = strcspn(p, delim); 2365 char savech; 2366 2367 savech = p[len]; 2368 p[len] = '\0'; 2369 obj = load_object(p, -1, NULL, 0); 2370 if (obj == NULL) 2371 return -1; /* XXX - cleanup */ 2372 obj->z_interpose = true; 2373 p[len] = savech; 2374 p += len; 2375 p += strspn(p, delim); 2376 } 2377 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2378 return 0; 2379 } 2380 2381 static const char * 2382 printable_path(const char *path) 2383 { 2384 2385 return (path == NULL ? "<unknown>" : path); 2386 } 2387 2388 /* 2389 * Load a shared object into memory, if it is not already loaded. The 2390 * object may be specified by name or by user-supplied file descriptor 2391 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2392 * duplicate is. 2393 * 2394 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2395 * on failure. 2396 */ 2397 static Obj_Entry * 2398 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2399 { 2400 Obj_Entry *obj; 2401 int fd; 2402 struct stat sb; 2403 char *path; 2404 2405 fd = -1; 2406 if (name != NULL) { 2407 TAILQ_FOREACH(obj, &obj_list, next) { 2408 if (obj->marker || obj->doomed) 2409 continue; 2410 if (object_match_name(obj, name)) 2411 return (obj); 2412 } 2413 2414 path = find_library(name, refobj, &fd); 2415 if (path == NULL) 2416 return (NULL); 2417 } else 2418 path = NULL; 2419 2420 if (fd >= 0) { 2421 /* 2422 * search_library_pathfds() opens a fresh file descriptor for the 2423 * library, so there is no need to dup(). 2424 */ 2425 } else if (fd_u == -1) { 2426 /* 2427 * If we didn't find a match by pathname, or the name is not 2428 * supplied, open the file and check again by device and inode. 2429 * This avoids false mismatches caused by multiple links or ".." 2430 * in pathnames. 2431 * 2432 * To avoid a race, we open the file and use fstat() rather than 2433 * using stat(). 2434 */ 2435 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2436 _rtld_error("Cannot open \"%s\"", path); 2437 free(path); 2438 return (NULL); 2439 } 2440 } else { 2441 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2442 if (fd == -1) { 2443 _rtld_error("Cannot dup fd"); 2444 free(path); 2445 return (NULL); 2446 } 2447 } 2448 if (fstat(fd, &sb) == -1) { 2449 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2450 close(fd); 2451 free(path); 2452 return NULL; 2453 } 2454 TAILQ_FOREACH(obj, &obj_list, next) { 2455 if (obj->marker || obj->doomed) 2456 continue; 2457 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2458 break; 2459 } 2460 if (obj != NULL && name != NULL) { 2461 object_add_name(obj, name); 2462 free(path); 2463 close(fd); 2464 return obj; 2465 } 2466 if (flags & RTLD_LO_NOLOAD) { 2467 free(path); 2468 close(fd); 2469 return (NULL); 2470 } 2471 2472 /* First use of this object, so we must map it in */ 2473 obj = do_load_object(fd, name, path, &sb, flags); 2474 if (obj == NULL) 2475 free(path); 2476 close(fd); 2477 2478 return obj; 2479 } 2480 2481 static Obj_Entry * 2482 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2483 int flags) 2484 { 2485 Obj_Entry *obj; 2486 struct statfs fs; 2487 2488 /* 2489 * but first, make sure that environment variables haven't been 2490 * used to circumvent the noexec flag on a filesystem. 2491 */ 2492 if (dangerous_ld_env) { 2493 if (fstatfs(fd, &fs) != 0) { 2494 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2495 return NULL; 2496 } 2497 if (fs.f_flags & MNT_NOEXEC) { 2498 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2499 return NULL; 2500 } 2501 } 2502 dbg("loading \"%s\"", printable_path(path)); 2503 obj = map_object(fd, printable_path(path), sbp); 2504 if (obj == NULL) 2505 return NULL; 2506 2507 /* 2508 * If DT_SONAME is present in the object, digest_dynamic2 already 2509 * added it to the object names. 2510 */ 2511 if (name != NULL) 2512 object_add_name(obj, name); 2513 obj->path = path; 2514 digest_dynamic(obj, 0); 2515 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2516 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2517 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2518 RTLD_LO_DLOPEN) { 2519 dbg("refusing to load non-loadable \"%s\"", obj->path); 2520 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2521 munmap(obj->mapbase, obj->mapsize); 2522 obj_free(obj); 2523 return (NULL); 2524 } 2525 2526 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2527 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2528 obj_count++; 2529 obj_loads++; 2530 linkmap_add(obj); /* for GDB & dlinfo() */ 2531 max_stack_flags |= obj->stack_flags; 2532 2533 dbg(" %p .. %p: %s", obj->mapbase, 2534 obj->mapbase + obj->mapsize - 1, obj->path); 2535 if (obj->textrel) 2536 dbg(" WARNING: %s has impure text", obj->path); 2537 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2538 obj->path); 2539 2540 return obj; 2541 } 2542 2543 static Obj_Entry * 2544 obj_from_addr(const void *addr) 2545 { 2546 Obj_Entry *obj; 2547 2548 TAILQ_FOREACH(obj, &obj_list, next) { 2549 if (obj->marker) 2550 continue; 2551 if (addr < (void *) obj->mapbase) 2552 continue; 2553 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2554 return obj; 2555 } 2556 return NULL; 2557 } 2558 2559 static void 2560 preinit_main(void) 2561 { 2562 Elf_Addr *preinit_addr; 2563 int index; 2564 2565 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2566 if (preinit_addr == NULL) 2567 return; 2568 2569 for (index = 0; index < obj_main->preinit_array_num; index++) { 2570 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2571 dbg("calling preinit function for %s at %p", obj_main->path, 2572 (void *)preinit_addr[index]); 2573 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2574 0, 0, obj_main->path); 2575 call_init_pointer(obj_main, preinit_addr[index]); 2576 } 2577 } 2578 } 2579 2580 /* 2581 * Call the finalization functions for each of the objects in "list" 2582 * belonging to the DAG of "root" and referenced once. If NULL "root" 2583 * is specified, every finalization function will be called regardless 2584 * of the reference count and the list elements won't be freed. All of 2585 * the objects are expected to have non-NULL fini functions. 2586 */ 2587 static void 2588 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2589 { 2590 Objlist_Entry *elm; 2591 char *saved_msg; 2592 Elf_Addr *fini_addr; 2593 int index; 2594 2595 assert(root == NULL || root->refcount == 1); 2596 2597 if (root != NULL) 2598 root->doomed = true; 2599 2600 /* 2601 * Preserve the current error message since a fini function might 2602 * call into the dynamic linker and overwrite it. 2603 */ 2604 saved_msg = errmsg_save(); 2605 do { 2606 STAILQ_FOREACH(elm, list, link) { 2607 if (root != NULL && (elm->obj->refcount != 1 || 2608 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2609 continue; 2610 /* Remove object from fini list to prevent recursive invocation. */ 2611 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2612 /* Ensure that new references cannot be acquired. */ 2613 elm->obj->doomed = true; 2614 2615 hold_object(elm->obj); 2616 lock_release(rtld_bind_lock, lockstate); 2617 /* 2618 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2619 * When this happens, DT_FINI_ARRAY is processed first. 2620 */ 2621 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2622 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2623 for (index = elm->obj->fini_array_num - 1; index >= 0; 2624 index--) { 2625 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2626 dbg("calling fini function for %s at %p", 2627 elm->obj->path, (void *)fini_addr[index]); 2628 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2629 (void *)fini_addr[index], 0, 0, elm->obj->path); 2630 call_initfini_pointer(elm->obj, fini_addr[index]); 2631 } 2632 } 2633 } 2634 if (elm->obj->fini != (Elf_Addr)NULL) { 2635 dbg("calling fini function for %s at %p", elm->obj->path, 2636 (void *)elm->obj->fini); 2637 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2638 0, 0, elm->obj->path); 2639 call_initfini_pointer(elm->obj, elm->obj->fini); 2640 } 2641 wlock_acquire(rtld_bind_lock, lockstate); 2642 unhold_object(elm->obj); 2643 /* No need to free anything if process is going down. */ 2644 if (root != NULL) 2645 free(elm); 2646 /* 2647 * We must restart the list traversal after every fini call 2648 * because a dlclose() call from the fini function or from 2649 * another thread might have modified the reference counts. 2650 */ 2651 break; 2652 } 2653 } while (elm != NULL); 2654 errmsg_restore(saved_msg); 2655 } 2656 2657 /* 2658 * Call the initialization functions for each of the objects in 2659 * "list". All of the objects are expected to have non-NULL init 2660 * functions. 2661 */ 2662 static void 2663 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2664 { 2665 Objlist_Entry *elm; 2666 Obj_Entry *obj; 2667 char *saved_msg; 2668 Elf_Addr *init_addr; 2669 void (*reg)(void (*)(void)); 2670 int index; 2671 2672 /* 2673 * Clean init_scanned flag so that objects can be rechecked and 2674 * possibly initialized earlier if any of vectors called below 2675 * cause the change by using dlopen. 2676 */ 2677 TAILQ_FOREACH(obj, &obj_list, next) { 2678 if (obj->marker) 2679 continue; 2680 obj->init_scanned = false; 2681 } 2682 2683 /* 2684 * Preserve the current error message since an init function might 2685 * call into the dynamic linker and overwrite it. 2686 */ 2687 saved_msg = errmsg_save(); 2688 STAILQ_FOREACH(elm, list, link) { 2689 if (elm->obj->init_done) /* Initialized early. */ 2690 continue; 2691 /* 2692 * Race: other thread might try to use this object before current 2693 * one completes the initialization. Not much can be done here 2694 * without better locking. 2695 */ 2696 elm->obj->init_done = true; 2697 hold_object(elm->obj); 2698 reg = NULL; 2699 if (elm->obj == obj_main && obj_main->crt_no_init) { 2700 reg = (void (*)(void (*)(void)))get_program_var_addr( 2701 "__libc_atexit", lockstate); 2702 } 2703 lock_release(rtld_bind_lock, lockstate); 2704 if (reg != NULL) { 2705 reg(rtld_exit); 2706 rtld_exit_ptr = rtld_nop_exit; 2707 } 2708 2709 /* 2710 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2711 * When this happens, DT_INIT is processed first. 2712 */ 2713 if (elm->obj->init != (Elf_Addr)NULL) { 2714 dbg("calling init function for %s at %p", elm->obj->path, 2715 (void *)elm->obj->init); 2716 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2717 0, 0, elm->obj->path); 2718 call_initfini_pointer(elm->obj, elm->obj->init); 2719 } 2720 init_addr = (Elf_Addr *)elm->obj->init_array; 2721 if (init_addr != NULL) { 2722 for (index = 0; index < elm->obj->init_array_num; index++) { 2723 if (init_addr[index] != 0 && init_addr[index] != 1) { 2724 dbg("calling init function for %s at %p", elm->obj->path, 2725 (void *)init_addr[index]); 2726 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2727 (void *)init_addr[index], 0, 0, elm->obj->path); 2728 call_init_pointer(elm->obj, init_addr[index]); 2729 } 2730 } 2731 } 2732 wlock_acquire(rtld_bind_lock, lockstate); 2733 unhold_object(elm->obj); 2734 } 2735 errmsg_restore(saved_msg); 2736 } 2737 2738 static void 2739 objlist_clear(Objlist *list) 2740 { 2741 Objlist_Entry *elm; 2742 2743 while (!STAILQ_EMPTY(list)) { 2744 elm = STAILQ_FIRST(list); 2745 STAILQ_REMOVE_HEAD(list, link); 2746 free(elm); 2747 } 2748 } 2749 2750 static Objlist_Entry * 2751 objlist_find(Objlist *list, const Obj_Entry *obj) 2752 { 2753 Objlist_Entry *elm; 2754 2755 STAILQ_FOREACH(elm, list, link) 2756 if (elm->obj == obj) 2757 return elm; 2758 return NULL; 2759 } 2760 2761 static void 2762 objlist_init(Objlist *list) 2763 { 2764 STAILQ_INIT(list); 2765 } 2766 2767 static void 2768 objlist_push_head(Objlist *list, Obj_Entry *obj) 2769 { 2770 Objlist_Entry *elm; 2771 2772 elm = NEW(Objlist_Entry); 2773 elm->obj = obj; 2774 STAILQ_INSERT_HEAD(list, elm, link); 2775 } 2776 2777 static void 2778 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2779 { 2780 Objlist_Entry *elm; 2781 2782 elm = NEW(Objlist_Entry); 2783 elm->obj = obj; 2784 STAILQ_INSERT_TAIL(list, elm, link); 2785 } 2786 2787 static void 2788 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2789 { 2790 Objlist_Entry *elm, *listelm; 2791 2792 STAILQ_FOREACH(listelm, list, link) { 2793 if (listelm->obj == listobj) 2794 break; 2795 } 2796 elm = NEW(Objlist_Entry); 2797 elm->obj = obj; 2798 if (listelm != NULL) 2799 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2800 else 2801 STAILQ_INSERT_TAIL(list, elm, link); 2802 } 2803 2804 static void 2805 objlist_remove(Objlist *list, Obj_Entry *obj) 2806 { 2807 Objlist_Entry *elm; 2808 2809 if ((elm = objlist_find(list, obj)) != NULL) { 2810 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2811 free(elm); 2812 } 2813 } 2814 2815 /* 2816 * Relocate dag rooted in the specified object. 2817 * Returns 0 on success, or -1 on failure. 2818 */ 2819 2820 static int 2821 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2822 int flags, RtldLockState *lockstate) 2823 { 2824 Objlist_Entry *elm; 2825 int error; 2826 2827 error = 0; 2828 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2829 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2830 lockstate); 2831 if (error == -1) 2832 break; 2833 } 2834 return (error); 2835 } 2836 2837 /* 2838 * Prepare for, or clean after, relocating an object marked with 2839 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2840 * segments are remapped read-write. After relocations are done, the 2841 * segment's permissions are returned back to the modes specified in 2842 * the phdrs. If any relocation happened, or always for wired 2843 * program, COW is triggered. 2844 */ 2845 static int 2846 reloc_textrel_prot(Obj_Entry *obj, bool before) 2847 { 2848 const Elf_Phdr *ph; 2849 void *base; 2850 size_t l, sz; 2851 int prot; 2852 2853 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2854 l--, ph++) { 2855 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2856 continue; 2857 base = obj->relocbase + trunc_page(ph->p_vaddr); 2858 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2859 trunc_page(ph->p_vaddr); 2860 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2861 if (mprotect(base, sz, prot) == -1) { 2862 _rtld_error("%s: Cannot write-%sable text segment: %s", 2863 obj->path, before ? "en" : "dis", 2864 rtld_strerror(errno)); 2865 return (-1); 2866 } 2867 } 2868 return (0); 2869 } 2870 2871 /* 2872 * Relocate single object. 2873 * Returns 0 on success, or -1 on failure. 2874 */ 2875 static int 2876 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2877 int flags, RtldLockState *lockstate) 2878 { 2879 2880 if (obj->relocated) 2881 return (0); 2882 obj->relocated = true; 2883 if (obj != rtldobj) 2884 dbg("relocating \"%s\"", obj->path); 2885 2886 if (obj->symtab == NULL || obj->strtab == NULL || 2887 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2888 _rtld_error("%s: Shared object has no run-time symbol table", 2889 obj->path); 2890 return (-1); 2891 } 2892 2893 /* There are relocations to the write-protected text segment. */ 2894 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2895 return (-1); 2896 2897 /* Process the non-PLT non-IFUNC relocations. */ 2898 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2899 return (-1); 2900 2901 /* Re-protected the text segment. */ 2902 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2903 return (-1); 2904 2905 /* Set the special PLT or GOT entries. */ 2906 init_pltgot(obj); 2907 2908 /* Process the PLT relocations. */ 2909 if (reloc_plt(obj, flags, lockstate) == -1) 2910 return (-1); 2911 /* Relocate the jump slots if we are doing immediate binding. */ 2912 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2913 lockstate) == -1) 2914 return (-1); 2915 2916 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2917 return (-1); 2918 2919 /* 2920 * Set up the magic number and version in the Obj_Entry. These 2921 * were checked in the crt1.o from the original ElfKit, so we 2922 * set them for backward compatibility. 2923 */ 2924 obj->magic = RTLD_MAGIC; 2925 obj->version = RTLD_VERSION; 2926 2927 return (0); 2928 } 2929 2930 /* 2931 * Relocate newly-loaded shared objects. The argument is a pointer to 2932 * the Obj_Entry for the first such object. All objects from the first 2933 * to the end of the list of objects are relocated. Returns 0 on success, 2934 * or -1 on failure. 2935 */ 2936 static int 2937 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2938 int flags, RtldLockState *lockstate) 2939 { 2940 Obj_Entry *obj; 2941 int error; 2942 2943 for (error = 0, obj = first; obj != NULL; 2944 obj = TAILQ_NEXT(obj, next)) { 2945 if (obj->marker) 2946 continue; 2947 error = relocate_object(obj, bind_now, rtldobj, flags, 2948 lockstate); 2949 if (error == -1) 2950 break; 2951 } 2952 return (error); 2953 } 2954 2955 /* 2956 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2957 * referencing STT_GNU_IFUNC symbols is postponed till the other 2958 * relocations are done. The indirect functions specified as 2959 * ifunc are allowed to call other symbols, so we need to have 2960 * objects relocated before asking for resolution from indirects. 2961 * 2962 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2963 * instead of the usual lazy handling of PLT slots. It is 2964 * consistent with how GNU does it. 2965 */ 2966 static int 2967 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2968 RtldLockState *lockstate) 2969 { 2970 2971 if (obj->ifuncs_resolved) 2972 return (0); 2973 obj->ifuncs_resolved = true; 2974 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 2975 return (0); 2976 if (obj_disable_relro(obj) == -1 || 2977 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 2978 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2979 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 2980 obj_enforce_relro(obj) == -1) 2981 return (-1); 2982 return (0); 2983 } 2984 2985 static int 2986 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2987 RtldLockState *lockstate) 2988 { 2989 Objlist_Entry *elm; 2990 Obj_Entry *obj; 2991 2992 STAILQ_FOREACH(elm, list, link) { 2993 obj = elm->obj; 2994 if (obj->marker) 2995 continue; 2996 if (resolve_object_ifunc(obj, bind_now, flags, 2997 lockstate) == -1) 2998 return (-1); 2999 } 3000 return (0); 3001 } 3002 3003 /* 3004 * Cleanup procedure. It will be called (by the atexit mechanism) just 3005 * before the process exits. 3006 */ 3007 static void 3008 rtld_exit(void) 3009 { 3010 RtldLockState lockstate; 3011 3012 wlock_acquire(rtld_bind_lock, &lockstate); 3013 dbg("rtld_exit()"); 3014 objlist_call_fini(&list_fini, NULL, &lockstate); 3015 /* No need to remove the items from the list, since we are exiting. */ 3016 if (!libmap_disable) 3017 lm_fini(); 3018 lock_release(rtld_bind_lock, &lockstate); 3019 } 3020 3021 static void 3022 rtld_nop_exit(void) 3023 { 3024 } 3025 3026 /* 3027 * Iterate over a search path, translate each element, and invoke the 3028 * callback on the result. 3029 */ 3030 static void * 3031 path_enumerate(const char *path, path_enum_proc callback, 3032 const char *refobj_path, void *arg) 3033 { 3034 const char *trans; 3035 if (path == NULL) 3036 return (NULL); 3037 3038 path += strspn(path, ":;"); 3039 while (*path != '\0') { 3040 size_t len; 3041 char *res; 3042 3043 len = strcspn(path, ":;"); 3044 trans = lm_findn(refobj_path, path, len); 3045 if (trans) 3046 res = callback(trans, strlen(trans), arg); 3047 else 3048 res = callback(path, len, arg); 3049 3050 if (res != NULL) 3051 return (res); 3052 3053 path += len; 3054 path += strspn(path, ":;"); 3055 } 3056 3057 return (NULL); 3058 } 3059 3060 struct try_library_args { 3061 const char *name; 3062 size_t namelen; 3063 char *buffer; 3064 size_t buflen; 3065 int fd; 3066 }; 3067 3068 static void * 3069 try_library_path(const char *dir, size_t dirlen, void *param) 3070 { 3071 struct try_library_args *arg; 3072 int fd; 3073 3074 arg = param; 3075 if (*dir == '/' || trust) { 3076 char *pathname; 3077 3078 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3079 return (NULL); 3080 3081 pathname = arg->buffer; 3082 strncpy(pathname, dir, dirlen); 3083 pathname[dirlen] = '/'; 3084 strcpy(pathname + dirlen + 1, arg->name); 3085 3086 dbg(" Trying \"%s\"", pathname); 3087 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3088 if (fd >= 0) { 3089 dbg(" Opened \"%s\", fd %d", pathname, fd); 3090 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3091 strcpy(pathname, arg->buffer); 3092 arg->fd = fd; 3093 return (pathname); 3094 } else { 3095 dbg(" Failed to open \"%s\": %s", 3096 pathname, rtld_strerror(errno)); 3097 } 3098 } 3099 return (NULL); 3100 } 3101 3102 static char * 3103 search_library_path(const char *name, const char *path, 3104 const char *refobj_path, int *fdp) 3105 { 3106 char *p; 3107 struct try_library_args arg; 3108 3109 if (path == NULL) 3110 return NULL; 3111 3112 arg.name = name; 3113 arg.namelen = strlen(name); 3114 arg.buffer = xmalloc(PATH_MAX); 3115 arg.buflen = PATH_MAX; 3116 arg.fd = -1; 3117 3118 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3119 *fdp = arg.fd; 3120 3121 free(arg.buffer); 3122 3123 return (p); 3124 } 3125 3126 3127 /* 3128 * Finds the library with the given name using the directory descriptors 3129 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3130 * 3131 * Returns a freshly-opened close-on-exec file descriptor for the library, 3132 * or -1 if the library cannot be found. 3133 */ 3134 static char * 3135 search_library_pathfds(const char *name, const char *path, int *fdp) 3136 { 3137 char *envcopy, *fdstr, *found, *last_token; 3138 size_t len; 3139 int dirfd, fd; 3140 3141 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3142 3143 /* Don't load from user-specified libdirs into setuid binaries. */ 3144 if (!trust) 3145 return (NULL); 3146 3147 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3148 if (path == NULL) 3149 return (NULL); 3150 3151 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3152 if (name[0] == '/') { 3153 dbg("Absolute path (%s) passed to %s", name, __func__); 3154 return (NULL); 3155 } 3156 3157 /* 3158 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3159 * copy of the path, as strtok_r rewrites separator tokens 3160 * with '\0'. 3161 */ 3162 found = NULL; 3163 envcopy = xstrdup(path); 3164 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3165 fdstr = strtok_r(NULL, ":", &last_token)) { 3166 dirfd = parse_integer(fdstr); 3167 if (dirfd < 0) { 3168 _rtld_error("failed to parse directory FD: '%s'", 3169 fdstr); 3170 break; 3171 } 3172 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3173 if (fd >= 0) { 3174 *fdp = fd; 3175 len = strlen(fdstr) + strlen(name) + 3; 3176 found = xmalloc(len); 3177 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3178 _rtld_error("error generating '%d/%s'", 3179 dirfd, name); 3180 rtld_die(); 3181 } 3182 dbg("open('%s') => %d", found, fd); 3183 break; 3184 } 3185 } 3186 free(envcopy); 3187 3188 return (found); 3189 } 3190 3191 3192 int 3193 dlclose(void *handle) 3194 { 3195 RtldLockState lockstate; 3196 int error; 3197 3198 wlock_acquire(rtld_bind_lock, &lockstate); 3199 error = dlclose_locked(handle, &lockstate); 3200 lock_release(rtld_bind_lock, &lockstate); 3201 return (error); 3202 } 3203 3204 static int 3205 dlclose_locked(void *handle, RtldLockState *lockstate) 3206 { 3207 Obj_Entry *root; 3208 3209 root = dlcheck(handle); 3210 if (root == NULL) 3211 return -1; 3212 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3213 root->path); 3214 3215 /* Unreference the object and its dependencies. */ 3216 root->dl_refcount--; 3217 3218 if (root->refcount == 1) { 3219 /* 3220 * The object will be no longer referenced, so we must unload it. 3221 * First, call the fini functions. 3222 */ 3223 objlist_call_fini(&list_fini, root, lockstate); 3224 3225 unref_dag(root); 3226 3227 /* Finish cleaning up the newly-unreferenced objects. */ 3228 GDB_STATE(RT_DELETE,&root->linkmap); 3229 unload_object(root, lockstate); 3230 GDB_STATE(RT_CONSISTENT,NULL); 3231 } else 3232 unref_dag(root); 3233 3234 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3235 return 0; 3236 } 3237 3238 char * 3239 dlerror(void) 3240 { 3241 char *msg = error_message; 3242 error_message = NULL; 3243 return msg; 3244 } 3245 3246 /* 3247 * This function is deprecated and has no effect. 3248 */ 3249 void 3250 dllockinit(void *context, 3251 void *(*_lock_create)(void *context) __unused, 3252 void (*_rlock_acquire)(void *lock) __unused, 3253 void (*_wlock_acquire)(void *lock) __unused, 3254 void (*_lock_release)(void *lock) __unused, 3255 void (*_lock_destroy)(void *lock) __unused, 3256 void (*context_destroy)(void *context)) 3257 { 3258 static void *cur_context; 3259 static void (*cur_context_destroy)(void *); 3260 3261 /* Just destroy the context from the previous call, if necessary. */ 3262 if (cur_context_destroy != NULL) 3263 cur_context_destroy(cur_context); 3264 cur_context = context; 3265 cur_context_destroy = context_destroy; 3266 } 3267 3268 void * 3269 dlopen(const char *name, int mode) 3270 { 3271 3272 return (rtld_dlopen(name, -1, mode)); 3273 } 3274 3275 void * 3276 fdlopen(int fd, int mode) 3277 { 3278 3279 return (rtld_dlopen(NULL, fd, mode)); 3280 } 3281 3282 static void * 3283 rtld_dlopen(const char *name, int fd, int mode) 3284 { 3285 RtldLockState lockstate; 3286 int lo_flags; 3287 3288 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3289 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3290 if (ld_tracing != NULL) { 3291 rlock_acquire(rtld_bind_lock, &lockstate); 3292 if (sigsetjmp(lockstate.env, 0) != 0) 3293 lock_upgrade(rtld_bind_lock, &lockstate); 3294 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3295 lock_release(rtld_bind_lock, &lockstate); 3296 } 3297 lo_flags = RTLD_LO_DLOPEN; 3298 if (mode & RTLD_NODELETE) 3299 lo_flags |= RTLD_LO_NODELETE; 3300 if (mode & RTLD_NOLOAD) 3301 lo_flags |= RTLD_LO_NOLOAD; 3302 if (ld_tracing != NULL) 3303 lo_flags |= RTLD_LO_TRACE; 3304 3305 return (dlopen_object(name, fd, obj_main, lo_flags, 3306 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3307 } 3308 3309 static void 3310 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3311 { 3312 3313 obj->dl_refcount--; 3314 unref_dag(obj); 3315 if (obj->refcount == 0) 3316 unload_object(obj, lockstate); 3317 } 3318 3319 static Obj_Entry * 3320 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3321 int mode, RtldLockState *lockstate) 3322 { 3323 Obj_Entry *old_obj_tail; 3324 Obj_Entry *obj; 3325 Objlist initlist; 3326 RtldLockState mlockstate; 3327 int result; 3328 3329 objlist_init(&initlist); 3330 3331 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3332 wlock_acquire(rtld_bind_lock, &mlockstate); 3333 lockstate = &mlockstate; 3334 } 3335 GDB_STATE(RT_ADD,NULL); 3336 3337 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3338 obj = NULL; 3339 if (name == NULL && fd == -1) { 3340 obj = obj_main; 3341 obj->refcount++; 3342 } else { 3343 obj = load_object(name, fd, refobj, lo_flags); 3344 } 3345 3346 if (obj) { 3347 obj->dl_refcount++; 3348 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3349 objlist_push_tail(&list_global, obj); 3350 if (globallist_next(old_obj_tail) != NULL) { 3351 /* We loaded something new. */ 3352 assert(globallist_next(old_obj_tail) == obj); 3353 result = 0; 3354 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3355 !allocate_tls_offset(obj)) { 3356 _rtld_error("%s: No space available " 3357 "for static Thread Local Storage", obj->path); 3358 result = -1; 3359 } 3360 if (result != -1) 3361 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3362 RTLD_LO_EARLY)); 3363 init_dag(obj); 3364 ref_dag(obj); 3365 if (result != -1) 3366 result = rtld_verify_versions(&obj->dagmembers); 3367 if (result != -1 && ld_tracing) 3368 goto trace; 3369 if (result == -1 || relocate_object_dag(obj, 3370 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3371 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3372 lockstate) == -1) { 3373 dlopen_cleanup(obj, lockstate); 3374 obj = NULL; 3375 } else if (lo_flags & RTLD_LO_EARLY) { 3376 /* 3377 * Do not call the init functions for early loaded 3378 * filtees. The image is still not initialized enough 3379 * for them to work. 3380 * 3381 * Our object is found by the global object list and 3382 * will be ordered among all init calls done right 3383 * before transferring control to main. 3384 */ 3385 } else { 3386 /* Make list of init functions to call. */ 3387 initlist_add_objects(obj, obj, &initlist); 3388 } 3389 /* 3390 * Process all no_delete or global objects here, given 3391 * them own DAGs to prevent their dependencies from being 3392 * unloaded. This has to be done after we have loaded all 3393 * of the dependencies, so that we do not miss any. 3394 */ 3395 if (obj != NULL) 3396 process_z(obj); 3397 } else { 3398 /* 3399 * Bump the reference counts for objects on this DAG. If 3400 * this is the first dlopen() call for the object that was 3401 * already loaded as a dependency, initialize the dag 3402 * starting at it. 3403 */ 3404 init_dag(obj); 3405 ref_dag(obj); 3406 3407 if ((lo_flags & RTLD_LO_TRACE) != 0) 3408 goto trace; 3409 } 3410 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3411 obj->z_nodelete) && !obj->ref_nodel) { 3412 dbg("obj %s nodelete", obj->path); 3413 ref_dag(obj); 3414 obj->z_nodelete = obj->ref_nodel = true; 3415 } 3416 } 3417 3418 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3419 name); 3420 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3421 3422 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3423 map_stacks_exec(lockstate); 3424 if (obj != NULL) 3425 distribute_static_tls(&initlist, lockstate); 3426 } 3427 3428 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3429 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3430 lockstate) == -1) { 3431 objlist_clear(&initlist); 3432 dlopen_cleanup(obj, lockstate); 3433 if (lockstate == &mlockstate) 3434 lock_release(rtld_bind_lock, lockstate); 3435 return (NULL); 3436 } 3437 3438 if (!(lo_flags & RTLD_LO_EARLY)) { 3439 /* Call the init functions. */ 3440 objlist_call_init(&initlist, lockstate); 3441 } 3442 objlist_clear(&initlist); 3443 if (lockstate == &mlockstate) 3444 lock_release(rtld_bind_lock, lockstate); 3445 return obj; 3446 trace: 3447 trace_loaded_objects(obj); 3448 if (lockstate == &mlockstate) 3449 lock_release(rtld_bind_lock, lockstate); 3450 exit(0); 3451 } 3452 3453 static void * 3454 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3455 int flags) 3456 { 3457 DoneList donelist; 3458 const Obj_Entry *obj, *defobj; 3459 const Elf_Sym *def; 3460 SymLook req; 3461 RtldLockState lockstate; 3462 tls_index ti; 3463 void *sym; 3464 int res; 3465 3466 def = NULL; 3467 defobj = NULL; 3468 symlook_init(&req, name); 3469 req.ventry = ve; 3470 req.flags = flags | SYMLOOK_IN_PLT; 3471 req.lockstate = &lockstate; 3472 3473 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3474 rlock_acquire(rtld_bind_lock, &lockstate); 3475 if (sigsetjmp(lockstate.env, 0) != 0) 3476 lock_upgrade(rtld_bind_lock, &lockstate); 3477 if (handle == NULL || handle == RTLD_NEXT || 3478 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3479 3480 if ((obj = obj_from_addr(retaddr)) == NULL) { 3481 _rtld_error("Cannot determine caller's shared object"); 3482 lock_release(rtld_bind_lock, &lockstate); 3483 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3484 return NULL; 3485 } 3486 if (handle == NULL) { /* Just the caller's shared object. */ 3487 res = symlook_obj(&req, obj); 3488 if (res == 0) { 3489 def = req.sym_out; 3490 defobj = req.defobj_out; 3491 } 3492 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3493 handle == RTLD_SELF) { /* ... caller included */ 3494 if (handle == RTLD_NEXT) 3495 obj = globallist_next(obj); 3496 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3497 if (obj->marker) 3498 continue; 3499 res = symlook_obj(&req, obj); 3500 if (res == 0) { 3501 if (def == NULL || 3502 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3503 def = req.sym_out; 3504 defobj = req.defobj_out; 3505 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3506 break; 3507 } 3508 } 3509 } 3510 /* 3511 * Search the dynamic linker itself, and possibly resolve the 3512 * symbol from there. This is how the application links to 3513 * dynamic linker services such as dlopen. 3514 */ 3515 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3516 res = symlook_obj(&req, &obj_rtld); 3517 if (res == 0) { 3518 def = req.sym_out; 3519 defobj = req.defobj_out; 3520 } 3521 } 3522 } else { 3523 assert(handle == RTLD_DEFAULT); 3524 res = symlook_default(&req, obj); 3525 if (res == 0) { 3526 defobj = req.defobj_out; 3527 def = req.sym_out; 3528 } 3529 } 3530 } else { 3531 if ((obj = dlcheck(handle)) == NULL) { 3532 lock_release(rtld_bind_lock, &lockstate); 3533 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3534 return NULL; 3535 } 3536 3537 donelist_init(&donelist); 3538 if (obj->mainprog) { 3539 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3540 res = symlook_global(&req, &donelist); 3541 if (res == 0) { 3542 def = req.sym_out; 3543 defobj = req.defobj_out; 3544 } 3545 /* 3546 * Search the dynamic linker itself, and possibly resolve the 3547 * symbol from there. This is how the application links to 3548 * dynamic linker services such as dlopen. 3549 */ 3550 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3551 res = symlook_obj(&req, &obj_rtld); 3552 if (res == 0) { 3553 def = req.sym_out; 3554 defobj = req.defobj_out; 3555 } 3556 } 3557 } 3558 else { 3559 /* Search the whole DAG rooted at the given object. */ 3560 res = symlook_list(&req, &obj->dagmembers, &donelist); 3561 if (res == 0) { 3562 def = req.sym_out; 3563 defobj = req.defobj_out; 3564 } 3565 } 3566 } 3567 3568 if (def != NULL) { 3569 lock_release(rtld_bind_lock, &lockstate); 3570 3571 /* 3572 * The value required by the caller is derived from the value 3573 * of the symbol. this is simply the relocated value of the 3574 * symbol. 3575 */ 3576 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3577 sym = make_function_pointer(def, defobj); 3578 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3579 sym = rtld_resolve_ifunc(defobj, def); 3580 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3581 ti.ti_module = defobj->tlsindex; 3582 ti.ti_offset = def->st_value; 3583 sym = __tls_get_addr(&ti); 3584 } else 3585 sym = defobj->relocbase + def->st_value; 3586 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3587 return (sym); 3588 } 3589 3590 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3591 ve != NULL ? ve->name : ""); 3592 lock_release(rtld_bind_lock, &lockstate); 3593 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3594 return NULL; 3595 } 3596 3597 void * 3598 dlsym(void *handle, const char *name) 3599 { 3600 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3601 SYMLOOK_DLSYM); 3602 } 3603 3604 dlfunc_t 3605 dlfunc(void *handle, const char *name) 3606 { 3607 union { 3608 void *d; 3609 dlfunc_t f; 3610 } rv; 3611 3612 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3613 SYMLOOK_DLSYM); 3614 return (rv.f); 3615 } 3616 3617 void * 3618 dlvsym(void *handle, const char *name, const char *version) 3619 { 3620 Ver_Entry ventry; 3621 3622 ventry.name = version; 3623 ventry.file = NULL; 3624 ventry.hash = elf_hash(version); 3625 ventry.flags= 0; 3626 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3627 SYMLOOK_DLSYM); 3628 } 3629 3630 int 3631 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3632 { 3633 const Obj_Entry *obj; 3634 RtldLockState lockstate; 3635 3636 rlock_acquire(rtld_bind_lock, &lockstate); 3637 obj = obj_from_addr(addr); 3638 if (obj == NULL) { 3639 _rtld_error("No shared object contains address"); 3640 lock_release(rtld_bind_lock, &lockstate); 3641 return (0); 3642 } 3643 rtld_fill_dl_phdr_info(obj, phdr_info); 3644 lock_release(rtld_bind_lock, &lockstate); 3645 return (1); 3646 } 3647 3648 int 3649 dladdr(const void *addr, Dl_info *info) 3650 { 3651 const Obj_Entry *obj; 3652 const Elf_Sym *def; 3653 void *symbol_addr; 3654 unsigned long symoffset; 3655 RtldLockState lockstate; 3656 3657 rlock_acquire(rtld_bind_lock, &lockstate); 3658 obj = obj_from_addr(addr); 3659 if (obj == NULL) { 3660 _rtld_error("No shared object contains address"); 3661 lock_release(rtld_bind_lock, &lockstate); 3662 return 0; 3663 } 3664 info->dli_fname = obj->path; 3665 info->dli_fbase = obj->mapbase; 3666 info->dli_saddr = (void *)0; 3667 info->dli_sname = NULL; 3668 3669 /* 3670 * Walk the symbol list looking for the symbol whose address is 3671 * closest to the address sent in. 3672 */ 3673 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3674 def = obj->symtab + symoffset; 3675 3676 /* 3677 * For skip the symbol if st_shndx is either SHN_UNDEF or 3678 * SHN_COMMON. 3679 */ 3680 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3681 continue; 3682 3683 /* 3684 * If the symbol is greater than the specified address, or if it 3685 * is further away from addr than the current nearest symbol, 3686 * then reject it. 3687 */ 3688 symbol_addr = obj->relocbase + def->st_value; 3689 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3690 continue; 3691 3692 /* Update our idea of the nearest symbol. */ 3693 info->dli_sname = obj->strtab + def->st_name; 3694 info->dli_saddr = symbol_addr; 3695 3696 /* Exact match? */ 3697 if (info->dli_saddr == addr) 3698 break; 3699 } 3700 lock_release(rtld_bind_lock, &lockstate); 3701 return 1; 3702 } 3703 3704 int 3705 dlinfo(void *handle, int request, void *p) 3706 { 3707 const Obj_Entry *obj; 3708 RtldLockState lockstate; 3709 int error; 3710 3711 rlock_acquire(rtld_bind_lock, &lockstate); 3712 3713 if (handle == NULL || handle == RTLD_SELF) { 3714 void *retaddr; 3715 3716 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3717 if ((obj = obj_from_addr(retaddr)) == NULL) 3718 _rtld_error("Cannot determine caller's shared object"); 3719 } else 3720 obj = dlcheck(handle); 3721 3722 if (obj == NULL) { 3723 lock_release(rtld_bind_lock, &lockstate); 3724 return (-1); 3725 } 3726 3727 error = 0; 3728 switch (request) { 3729 case RTLD_DI_LINKMAP: 3730 *((struct link_map const **)p) = &obj->linkmap; 3731 break; 3732 case RTLD_DI_ORIGIN: 3733 error = rtld_dirname(obj->path, p); 3734 break; 3735 3736 case RTLD_DI_SERINFOSIZE: 3737 case RTLD_DI_SERINFO: 3738 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3739 break; 3740 3741 default: 3742 _rtld_error("Invalid request %d passed to dlinfo()", request); 3743 error = -1; 3744 } 3745 3746 lock_release(rtld_bind_lock, &lockstate); 3747 3748 return (error); 3749 } 3750 3751 static void 3752 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3753 { 3754 3755 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3756 phdr_info->dlpi_name = obj->path; 3757 phdr_info->dlpi_phdr = obj->phdr; 3758 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3759 phdr_info->dlpi_tls_modid = obj->tlsindex; 3760 phdr_info->dlpi_tls_data = obj->tlsinit; 3761 phdr_info->dlpi_adds = obj_loads; 3762 phdr_info->dlpi_subs = obj_loads - obj_count; 3763 } 3764 3765 int 3766 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3767 { 3768 struct dl_phdr_info phdr_info; 3769 Obj_Entry *obj, marker; 3770 RtldLockState bind_lockstate, phdr_lockstate; 3771 int error; 3772 3773 init_marker(&marker); 3774 error = 0; 3775 3776 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3777 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3778 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3779 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3780 rtld_fill_dl_phdr_info(obj, &phdr_info); 3781 hold_object(obj); 3782 lock_release(rtld_bind_lock, &bind_lockstate); 3783 3784 error = callback(&phdr_info, sizeof phdr_info, param); 3785 3786 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3787 unhold_object(obj); 3788 obj = globallist_next(&marker); 3789 TAILQ_REMOVE(&obj_list, &marker, next); 3790 if (error != 0) { 3791 lock_release(rtld_bind_lock, &bind_lockstate); 3792 lock_release(rtld_phdr_lock, &phdr_lockstate); 3793 return (error); 3794 } 3795 } 3796 3797 if (error == 0) { 3798 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3799 lock_release(rtld_bind_lock, &bind_lockstate); 3800 error = callback(&phdr_info, sizeof(phdr_info), param); 3801 } 3802 lock_release(rtld_phdr_lock, &phdr_lockstate); 3803 return (error); 3804 } 3805 3806 static void * 3807 fill_search_info(const char *dir, size_t dirlen, void *param) 3808 { 3809 struct fill_search_info_args *arg; 3810 3811 arg = param; 3812 3813 if (arg->request == RTLD_DI_SERINFOSIZE) { 3814 arg->serinfo->dls_cnt ++; 3815 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3816 } else { 3817 struct dl_serpath *s_entry; 3818 3819 s_entry = arg->serpath; 3820 s_entry->dls_name = arg->strspace; 3821 s_entry->dls_flags = arg->flags; 3822 3823 strncpy(arg->strspace, dir, dirlen); 3824 arg->strspace[dirlen] = '\0'; 3825 3826 arg->strspace += dirlen + 1; 3827 arg->serpath++; 3828 } 3829 3830 return (NULL); 3831 } 3832 3833 static int 3834 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3835 { 3836 struct dl_serinfo _info; 3837 struct fill_search_info_args args; 3838 3839 args.request = RTLD_DI_SERINFOSIZE; 3840 args.serinfo = &_info; 3841 3842 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3843 _info.dls_cnt = 0; 3844 3845 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3846 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3847 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3848 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3849 if (!obj->z_nodeflib) 3850 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3851 3852 3853 if (request == RTLD_DI_SERINFOSIZE) { 3854 info->dls_size = _info.dls_size; 3855 info->dls_cnt = _info.dls_cnt; 3856 return (0); 3857 } 3858 3859 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3860 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3861 return (-1); 3862 } 3863 3864 args.request = RTLD_DI_SERINFO; 3865 args.serinfo = info; 3866 args.serpath = &info->dls_serpath[0]; 3867 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3868 3869 args.flags = LA_SER_RUNPATH; 3870 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3871 return (-1); 3872 3873 args.flags = LA_SER_LIBPATH; 3874 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3875 return (-1); 3876 3877 args.flags = LA_SER_RUNPATH; 3878 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3879 return (-1); 3880 3881 args.flags = LA_SER_CONFIG; 3882 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3883 != NULL) 3884 return (-1); 3885 3886 args.flags = LA_SER_DEFAULT; 3887 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3888 fill_search_info, NULL, &args) != NULL) 3889 return (-1); 3890 return (0); 3891 } 3892 3893 static int 3894 rtld_dirname(const char *path, char *bname) 3895 { 3896 const char *endp; 3897 3898 /* Empty or NULL string gets treated as "." */ 3899 if (path == NULL || *path == '\0') { 3900 bname[0] = '.'; 3901 bname[1] = '\0'; 3902 return (0); 3903 } 3904 3905 /* Strip trailing slashes */ 3906 endp = path + strlen(path) - 1; 3907 while (endp > path && *endp == '/') 3908 endp--; 3909 3910 /* Find the start of the dir */ 3911 while (endp > path && *endp != '/') 3912 endp--; 3913 3914 /* Either the dir is "/" or there are no slashes */ 3915 if (endp == path) { 3916 bname[0] = *endp == '/' ? '/' : '.'; 3917 bname[1] = '\0'; 3918 return (0); 3919 } else { 3920 do { 3921 endp--; 3922 } while (endp > path && *endp == '/'); 3923 } 3924 3925 if (endp - path + 2 > PATH_MAX) 3926 { 3927 _rtld_error("Filename is too long: %s", path); 3928 return(-1); 3929 } 3930 3931 strncpy(bname, path, endp - path + 1); 3932 bname[endp - path + 1] = '\0'; 3933 return (0); 3934 } 3935 3936 static int 3937 rtld_dirname_abs(const char *path, char *base) 3938 { 3939 char *last; 3940 3941 if (realpath(path, base) == NULL) 3942 return (-1); 3943 dbg("%s -> %s", path, base); 3944 last = strrchr(base, '/'); 3945 if (last == NULL) 3946 return (-1); 3947 if (last != base) 3948 *last = '\0'; 3949 return (0); 3950 } 3951 3952 static void 3953 linkmap_add(Obj_Entry *obj) 3954 { 3955 struct link_map *l = &obj->linkmap; 3956 struct link_map *prev; 3957 3958 obj->linkmap.l_name = obj->path; 3959 obj->linkmap.l_addr = obj->mapbase; 3960 obj->linkmap.l_ld = obj->dynamic; 3961 #ifdef __mips__ 3962 /* GDB needs load offset on MIPS to use the symbols */ 3963 obj->linkmap.l_offs = obj->relocbase; 3964 #endif 3965 3966 if (r_debug.r_map == NULL) { 3967 r_debug.r_map = l; 3968 return; 3969 } 3970 3971 /* 3972 * Scan to the end of the list, but not past the entry for the 3973 * dynamic linker, which we want to keep at the very end. 3974 */ 3975 for (prev = r_debug.r_map; 3976 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3977 prev = prev->l_next) 3978 ; 3979 3980 /* Link in the new entry. */ 3981 l->l_prev = prev; 3982 l->l_next = prev->l_next; 3983 if (l->l_next != NULL) 3984 l->l_next->l_prev = l; 3985 prev->l_next = l; 3986 } 3987 3988 static void 3989 linkmap_delete(Obj_Entry *obj) 3990 { 3991 struct link_map *l = &obj->linkmap; 3992 3993 if (l->l_prev == NULL) { 3994 if ((r_debug.r_map = l->l_next) != NULL) 3995 l->l_next->l_prev = NULL; 3996 return; 3997 } 3998 3999 if ((l->l_prev->l_next = l->l_next) != NULL) 4000 l->l_next->l_prev = l->l_prev; 4001 } 4002 4003 /* 4004 * Function for the debugger to set a breakpoint on to gain control. 4005 * 4006 * The two parameters allow the debugger to easily find and determine 4007 * what the runtime loader is doing and to whom it is doing it. 4008 * 4009 * When the loadhook trap is hit (r_debug_state, set at program 4010 * initialization), the arguments can be found on the stack: 4011 * 4012 * +8 struct link_map *m 4013 * +4 struct r_debug *rd 4014 * +0 RetAddr 4015 */ 4016 void 4017 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4018 { 4019 /* 4020 * The following is a hack to force the compiler to emit calls to 4021 * this function, even when optimizing. If the function is empty, 4022 * the compiler is not obliged to emit any code for calls to it, 4023 * even when marked __noinline. However, gdb depends on those 4024 * calls being made. 4025 */ 4026 __compiler_membar(); 4027 } 4028 4029 /* 4030 * A function called after init routines have completed. This can be used to 4031 * break before a program's entry routine is called, and can be used when 4032 * main is not available in the symbol table. 4033 */ 4034 void 4035 _r_debug_postinit(struct link_map *m __unused) 4036 { 4037 4038 /* See r_debug_state(). */ 4039 __compiler_membar(); 4040 } 4041 4042 static void 4043 release_object(Obj_Entry *obj) 4044 { 4045 4046 if (obj->holdcount > 0) { 4047 obj->unholdfree = true; 4048 return; 4049 } 4050 munmap(obj->mapbase, obj->mapsize); 4051 linkmap_delete(obj); 4052 obj_free(obj); 4053 } 4054 4055 /* 4056 * Get address of the pointer variable in the main program. 4057 * Prefer non-weak symbol over the weak one. 4058 */ 4059 static const void ** 4060 get_program_var_addr(const char *name, RtldLockState *lockstate) 4061 { 4062 SymLook req; 4063 DoneList donelist; 4064 4065 symlook_init(&req, name); 4066 req.lockstate = lockstate; 4067 donelist_init(&donelist); 4068 if (symlook_global(&req, &donelist) != 0) 4069 return (NULL); 4070 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4071 return ((const void **)make_function_pointer(req.sym_out, 4072 req.defobj_out)); 4073 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4074 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4075 else 4076 return ((const void **)(req.defobj_out->relocbase + 4077 req.sym_out->st_value)); 4078 } 4079 4080 /* 4081 * Set a pointer variable in the main program to the given value. This 4082 * is used to set key variables such as "environ" before any of the 4083 * init functions are called. 4084 */ 4085 static void 4086 set_program_var(const char *name, const void *value) 4087 { 4088 const void **addr; 4089 4090 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4091 dbg("\"%s\": *%p <-- %p", name, addr, value); 4092 *addr = value; 4093 } 4094 } 4095 4096 /* 4097 * Search the global objects, including dependencies and main object, 4098 * for the given symbol. 4099 */ 4100 static int 4101 symlook_global(SymLook *req, DoneList *donelist) 4102 { 4103 SymLook req1; 4104 const Objlist_Entry *elm; 4105 int res; 4106 4107 symlook_init_from_req(&req1, req); 4108 4109 /* Search all objects loaded at program start up. */ 4110 if (req->defobj_out == NULL || 4111 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4112 res = symlook_list(&req1, &list_main, donelist); 4113 if (res == 0 && (req->defobj_out == NULL || 4114 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4115 req->sym_out = req1.sym_out; 4116 req->defobj_out = req1.defobj_out; 4117 assert(req->defobj_out != NULL); 4118 } 4119 } 4120 4121 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4122 STAILQ_FOREACH(elm, &list_global, link) { 4123 if (req->defobj_out != NULL && 4124 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4125 break; 4126 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4127 if (res == 0 && (req->defobj_out == NULL || 4128 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4129 req->sym_out = req1.sym_out; 4130 req->defobj_out = req1.defobj_out; 4131 assert(req->defobj_out != NULL); 4132 } 4133 } 4134 4135 return (req->sym_out != NULL ? 0 : ESRCH); 4136 } 4137 4138 /* 4139 * Given a symbol name in a referencing object, find the corresponding 4140 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4141 * no definition was found. Returns a pointer to the Obj_Entry of the 4142 * defining object via the reference parameter DEFOBJ_OUT. 4143 */ 4144 static int 4145 symlook_default(SymLook *req, const Obj_Entry *refobj) 4146 { 4147 DoneList donelist; 4148 const Objlist_Entry *elm; 4149 SymLook req1; 4150 int res; 4151 4152 donelist_init(&donelist); 4153 symlook_init_from_req(&req1, req); 4154 4155 /* 4156 * Look first in the referencing object if linked symbolically, 4157 * and similarly handle protected symbols. 4158 */ 4159 res = symlook_obj(&req1, refobj); 4160 if (res == 0 && (refobj->symbolic || 4161 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4162 req->sym_out = req1.sym_out; 4163 req->defobj_out = req1.defobj_out; 4164 assert(req->defobj_out != NULL); 4165 } 4166 if (refobj->symbolic || req->defobj_out != NULL) 4167 donelist_check(&donelist, refobj); 4168 4169 symlook_global(req, &donelist); 4170 4171 /* Search all dlopened DAGs containing the referencing object. */ 4172 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4173 if (req->sym_out != NULL && 4174 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4175 break; 4176 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4177 if (res == 0 && (req->sym_out == NULL || 4178 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4179 req->sym_out = req1.sym_out; 4180 req->defobj_out = req1.defobj_out; 4181 assert(req->defobj_out != NULL); 4182 } 4183 } 4184 4185 /* 4186 * Search the dynamic linker itself, and possibly resolve the 4187 * symbol from there. This is how the application links to 4188 * dynamic linker services such as dlopen. 4189 */ 4190 if (req->sym_out == NULL || 4191 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4192 res = symlook_obj(&req1, &obj_rtld); 4193 if (res == 0) { 4194 req->sym_out = req1.sym_out; 4195 req->defobj_out = req1.defobj_out; 4196 assert(req->defobj_out != NULL); 4197 } 4198 } 4199 4200 return (req->sym_out != NULL ? 0 : ESRCH); 4201 } 4202 4203 static int 4204 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4205 { 4206 const Elf_Sym *def; 4207 const Obj_Entry *defobj; 4208 const Objlist_Entry *elm; 4209 SymLook req1; 4210 int res; 4211 4212 def = NULL; 4213 defobj = NULL; 4214 STAILQ_FOREACH(elm, objlist, link) { 4215 if (donelist_check(dlp, elm->obj)) 4216 continue; 4217 symlook_init_from_req(&req1, req); 4218 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4219 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4220 def = req1.sym_out; 4221 defobj = req1.defobj_out; 4222 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4223 break; 4224 } 4225 } 4226 } 4227 if (def != NULL) { 4228 req->sym_out = def; 4229 req->defobj_out = defobj; 4230 return (0); 4231 } 4232 return (ESRCH); 4233 } 4234 4235 /* 4236 * Search the chain of DAGS cointed to by the given Needed_Entry 4237 * for a symbol of the given name. Each DAG is scanned completely 4238 * before advancing to the next one. Returns a pointer to the symbol, 4239 * or NULL if no definition was found. 4240 */ 4241 static int 4242 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4243 { 4244 const Elf_Sym *def; 4245 const Needed_Entry *n; 4246 const Obj_Entry *defobj; 4247 SymLook req1; 4248 int res; 4249 4250 def = NULL; 4251 defobj = NULL; 4252 symlook_init_from_req(&req1, req); 4253 for (n = needed; n != NULL; n = n->next) { 4254 if (n->obj == NULL || 4255 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4256 continue; 4257 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4258 def = req1.sym_out; 4259 defobj = req1.defobj_out; 4260 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4261 break; 4262 } 4263 } 4264 if (def != NULL) { 4265 req->sym_out = def; 4266 req->defobj_out = defobj; 4267 return (0); 4268 } 4269 return (ESRCH); 4270 } 4271 4272 /* 4273 * Search the symbol table of a single shared object for a symbol of 4274 * the given name and version, if requested. Returns a pointer to the 4275 * symbol, or NULL if no definition was found. If the object is 4276 * filter, return filtered symbol from filtee. 4277 * 4278 * The symbol's hash value is passed in for efficiency reasons; that 4279 * eliminates many recomputations of the hash value. 4280 */ 4281 int 4282 symlook_obj(SymLook *req, const Obj_Entry *obj) 4283 { 4284 DoneList donelist; 4285 SymLook req1; 4286 int flags, res, mres; 4287 4288 /* 4289 * If there is at least one valid hash at this point, we prefer to 4290 * use the faster GNU version if available. 4291 */ 4292 if (obj->valid_hash_gnu) 4293 mres = symlook_obj1_gnu(req, obj); 4294 else if (obj->valid_hash_sysv) 4295 mres = symlook_obj1_sysv(req, obj); 4296 else 4297 return (EINVAL); 4298 4299 if (mres == 0) { 4300 if (obj->needed_filtees != NULL) { 4301 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4302 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4303 donelist_init(&donelist); 4304 symlook_init_from_req(&req1, req); 4305 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4306 if (res == 0) { 4307 req->sym_out = req1.sym_out; 4308 req->defobj_out = req1.defobj_out; 4309 } 4310 return (res); 4311 } 4312 if (obj->needed_aux_filtees != NULL) { 4313 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4314 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4315 donelist_init(&donelist); 4316 symlook_init_from_req(&req1, req); 4317 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4318 if (res == 0) { 4319 req->sym_out = req1.sym_out; 4320 req->defobj_out = req1.defobj_out; 4321 return (res); 4322 } 4323 } 4324 } 4325 return (mres); 4326 } 4327 4328 /* Symbol match routine common to both hash functions */ 4329 static bool 4330 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4331 const unsigned long symnum) 4332 { 4333 Elf_Versym verndx; 4334 const Elf_Sym *symp; 4335 const char *strp; 4336 4337 symp = obj->symtab + symnum; 4338 strp = obj->strtab + symp->st_name; 4339 4340 switch (ELF_ST_TYPE(symp->st_info)) { 4341 case STT_FUNC: 4342 case STT_NOTYPE: 4343 case STT_OBJECT: 4344 case STT_COMMON: 4345 case STT_GNU_IFUNC: 4346 if (symp->st_value == 0) 4347 return (false); 4348 /* fallthrough */ 4349 case STT_TLS: 4350 if (symp->st_shndx != SHN_UNDEF) 4351 break; 4352 #ifndef __mips__ 4353 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4354 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4355 break; 4356 #endif 4357 /* fallthrough */ 4358 default: 4359 return (false); 4360 } 4361 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4362 return (false); 4363 4364 if (req->ventry == NULL) { 4365 if (obj->versyms != NULL) { 4366 verndx = VER_NDX(obj->versyms[symnum]); 4367 if (verndx > obj->vernum) { 4368 _rtld_error( 4369 "%s: symbol %s references wrong version %d", 4370 obj->path, obj->strtab + symnum, verndx); 4371 return (false); 4372 } 4373 /* 4374 * If we are not called from dlsym (i.e. this 4375 * is a normal relocation from unversioned 4376 * binary), accept the symbol immediately if 4377 * it happens to have first version after this 4378 * shared object became versioned. Otherwise, 4379 * if symbol is versioned and not hidden, 4380 * remember it. If it is the only symbol with 4381 * this name exported by the shared object, it 4382 * will be returned as a match by the calling 4383 * function. If symbol is global (verndx < 2) 4384 * accept it unconditionally. 4385 */ 4386 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4387 verndx == VER_NDX_GIVEN) { 4388 result->sym_out = symp; 4389 return (true); 4390 } 4391 else if (verndx >= VER_NDX_GIVEN) { 4392 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4393 == 0) { 4394 if (result->vsymp == NULL) 4395 result->vsymp = symp; 4396 result->vcount++; 4397 } 4398 return (false); 4399 } 4400 } 4401 result->sym_out = symp; 4402 return (true); 4403 } 4404 if (obj->versyms == NULL) { 4405 if (object_match_name(obj, req->ventry->name)) { 4406 _rtld_error("%s: object %s should provide version %s " 4407 "for symbol %s", obj_rtld.path, obj->path, 4408 req->ventry->name, obj->strtab + symnum); 4409 return (false); 4410 } 4411 } else { 4412 verndx = VER_NDX(obj->versyms[symnum]); 4413 if (verndx > obj->vernum) { 4414 _rtld_error("%s: symbol %s references wrong version %d", 4415 obj->path, obj->strtab + symnum, verndx); 4416 return (false); 4417 } 4418 if (obj->vertab[verndx].hash != req->ventry->hash || 4419 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4420 /* 4421 * Version does not match. Look if this is a 4422 * global symbol and if it is not hidden. If 4423 * global symbol (verndx < 2) is available, 4424 * use it. Do not return symbol if we are 4425 * called by dlvsym, because dlvsym looks for 4426 * a specific version and default one is not 4427 * what dlvsym wants. 4428 */ 4429 if ((req->flags & SYMLOOK_DLSYM) || 4430 (verndx >= VER_NDX_GIVEN) || 4431 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4432 return (false); 4433 } 4434 } 4435 result->sym_out = symp; 4436 return (true); 4437 } 4438 4439 /* 4440 * Search for symbol using SysV hash function. 4441 * obj->buckets is known not to be NULL at this point; the test for this was 4442 * performed with the obj->valid_hash_sysv assignment. 4443 */ 4444 static int 4445 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4446 { 4447 unsigned long symnum; 4448 Sym_Match_Result matchres; 4449 4450 matchres.sym_out = NULL; 4451 matchres.vsymp = NULL; 4452 matchres.vcount = 0; 4453 4454 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4455 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4456 if (symnum >= obj->nchains) 4457 return (ESRCH); /* Bad object */ 4458 4459 if (matched_symbol(req, obj, &matchres, symnum)) { 4460 req->sym_out = matchres.sym_out; 4461 req->defobj_out = obj; 4462 return (0); 4463 } 4464 } 4465 if (matchres.vcount == 1) { 4466 req->sym_out = matchres.vsymp; 4467 req->defobj_out = obj; 4468 return (0); 4469 } 4470 return (ESRCH); 4471 } 4472 4473 /* Search for symbol using GNU hash function */ 4474 static int 4475 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4476 { 4477 Elf_Addr bloom_word; 4478 const Elf32_Word *hashval; 4479 Elf32_Word bucket; 4480 Sym_Match_Result matchres; 4481 unsigned int h1, h2; 4482 unsigned long symnum; 4483 4484 matchres.sym_out = NULL; 4485 matchres.vsymp = NULL; 4486 matchres.vcount = 0; 4487 4488 /* Pick right bitmask word from Bloom filter array */ 4489 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4490 obj->maskwords_bm_gnu]; 4491 4492 /* Calculate modulus word size of gnu hash and its derivative */ 4493 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4494 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4495 4496 /* Filter out the "definitely not in set" queries */ 4497 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4498 return (ESRCH); 4499 4500 /* Locate hash chain and corresponding value element*/ 4501 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4502 if (bucket == 0) 4503 return (ESRCH); 4504 hashval = &obj->chain_zero_gnu[bucket]; 4505 do { 4506 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4507 symnum = hashval - obj->chain_zero_gnu; 4508 if (matched_symbol(req, obj, &matchres, symnum)) { 4509 req->sym_out = matchres.sym_out; 4510 req->defobj_out = obj; 4511 return (0); 4512 } 4513 } 4514 } while ((*hashval++ & 1) == 0); 4515 if (matchres.vcount == 1) { 4516 req->sym_out = matchres.vsymp; 4517 req->defobj_out = obj; 4518 return (0); 4519 } 4520 return (ESRCH); 4521 } 4522 4523 static void 4524 trace_loaded_objects(Obj_Entry *obj) 4525 { 4526 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4527 int c; 4528 4529 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4530 main_local = ""; 4531 4532 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4533 fmt1 = "\t%o => %p (%x)\n"; 4534 4535 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4536 fmt2 = "\t%o (%x)\n"; 4537 4538 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4539 4540 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4541 Needed_Entry *needed; 4542 const char *name, *path; 4543 bool is_lib; 4544 4545 if (obj->marker) 4546 continue; 4547 if (list_containers && obj->needed != NULL) 4548 rtld_printf("%s:\n", obj->path); 4549 for (needed = obj->needed; needed; needed = needed->next) { 4550 if (needed->obj != NULL) { 4551 if (needed->obj->traced && !list_containers) 4552 continue; 4553 needed->obj->traced = true; 4554 path = needed->obj->path; 4555 } else 4556 path = "not found"; 4557 4558 name = obj->strtab + needed->name; 4559 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4560 4561 fmt = is_lib ? fmt1 : fmt2; 4562 while ((c = *fmt++) != '\0') { 4563 switch (c) { 4564 default: 4565 rtld_putchar(c); 4566 continue; 4567 case '\\': 4568 switch (c = *fmt) { 4569 case '\0': 4570 continue; 4571 case 'n': 4572 rtld_putchar('\n'); 4573 break; 4574 case 't': 4575 rtld_putchar('\t'); 4576 break; 4577 } 4578 break; 4579 case '%': 4580 switch (c = *fmt) { 4581 case '\0': 4582 continue; 4583 case '%': 4584 default: 4585 rtld_putchar(c); 4586 break; 4587 case 'A': 4588 rtld_putstr(main_local); 4589 break; 4590 case 'a': 4591 rtld_putstr(obj_main->path); 4592 break; 4593 case 'o': 4594 rtld_putstr(name); 4595 break; 4596 #if 0 4597 case 'm': 4598 rtld_printf("%d", sodp->sod_major); 4599 break; 4600 case 'n': 4601 rtld_printf("%d", sodp->sod_minor); 4602 break; 4603 #endif 4604 case 'p': 4605 rtld_putstr(path); 4606 break; 4607 case 'x': 4608 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4609 0); 4610 break; 4611 } 4612 break; 4613 } 4614 ++fmt; 4615 } 4616 } 4617 } 4618 } 4619 4620 /* 4621 * Unload a dlopened object and its dependencies from memory and from 4622 * our data structures. It is assumed that the DAG rooted in the 4623 * object has already been unreferenced, and that the object has a 4624 * reference count of 0. 4625 */ 4626 static void 4627 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4628 { 4629 Obj_Entry marker, *obj, *next; 4630 4631 assert(root->refcount == 0); 4632 4633 /* 4634 * Pass over the DAG removing unreferenced objects from 4635 * appropriate lists. 4636 */ 4637 unlink_object(root); 4638 4639 /* Unmap all objects that are no longer referenced. */ 4640 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4641 next = TAILQ_NEXT(obj, next); 4642 if (obj->marker || obj->refcount != 0) 4643 continue; 4644 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4645 obj->mapsize, 0, obj->path); 4646 dbg("unloading \"%s\"", obj->path); 4647 /* 4648 * Unlink the object now to prevent new references from 4649 * being acquired while the bind lock is dropped in 4650 * recursive dlclose() invocations. 4651 */ 4652 TAILQ_REMOVE(&obj_list, obj, next); 4653 obj_count--; 4654 4655 if (obj->filtees_loaded) { 4656 if (next != NULL) { 4657 init_marker(&marker); 4658 TAILQ_INSERT_BEFORE(next, &marker, next); 4659 unload_filtees(obj, lockstate); 4660 next = TAILQ_NEXT(&marker, next); 4661 TAILQ_REMOVE(&obj_list, &marker, next); 4662 } else 4663 unload_filtees(obj, lockstate); 4664 } 4665 release_object(obj); 4666 } 4667 } 4668 4669 static void 4670 unlink_object(Obj_Entry *root) 4671 { 4672 Objlist_Entry *elm; 4673 4674 if (root->refcount == 0) { 4675 /* Remove the object from the RTLD_GLOBAL list. */ 4676 objlist_remove(&list_global, root); 4677 4678 /* Remove the object from all objects' DAG lists. */ 4679 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4680 objlist_remove(&elm->obj->dldags, root); 4681 if (elm->obj != root) 4682 unlink_object(elm->obj); 4683 } 4684 } 4685 } 4686 4687 static void 4688 ref_dag(Obj_Entry *root) 4689 { 4690 Objlist_Entry *elm; 4691 4692 assert(root->dag_inited); 4693 STAILQ_FOREACH(elm, &root->dagmembers, link) 4694 elm->obj->refcount++; 4695 } 4696 4697 static void 4698 unref_dag(Obj_Entry *root) 4699 { 4700 Objlist_Entry *elm; 4701 4702 assert(root->dag_inited); 4703 STAILQ_FOREACH(elm, &root->dagmembers, link) 4704 elm->obj->refcount--; 4705 } 4706 4707 /* 4708 * Common code for MD __tls_get_addr(). 4709 */ 4710 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4711 static void * 4712 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4713 { 4714 Elf_Addr *newdtv, *dtv; 4715 RtldLockState lockstate; 4716 int to_copy; 4717 4718 dtv = *dtvp; 4719 /* Check dtv generation in case new modules have arrived */ 4720 if (dtv[0] != tls_dtv_generation) { 4721 wlock_acquire(rtld_bind_lock, &lockstate); 4722 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4723 to_copy = dtv[1]; 4724 if (to_copy > tls_max_index) 4725 to_copy = tls_max_index; 4726 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4727 newdtv[0] = tls_dtv_generation; 4728 newdtv[1] = tls_max_index; 4729 free(dtv); 4730 lock_release(rtld_bind_lock, &lockstate); 4731 dtv = *dtvp = newdtv; 4732 } 4733 4734 /* Dynamically allocate module TLS if necessary */ 4735 if (dtv[index + 1] == 0) { 4736 /* Signal safe, wlock will block out signals. */ 4737 wlock_acquire(rtld_bind_lock, &lockstate); 4738 if (!dtv[index + 1]) 4739 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4740 lock_release(rtld_bind_lock, &lockstate); 4741 } 4742 return ((void *)(dtv[index + 1] + offset)); 4743 } 4744 4745 void * 4746 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4747 { 4748 Elf_Addr *dtv; 4749 4750 dtv = *dtvp; 4751 /* Check dtv generation in case new modules have arrived */ 4752 if (__predict_true(dtv[0] == tls_dtv_generation && 4753 dtv[index + 1] != 0)) 4754 return ((void *)(dtv[index + 1] + offset)); 4755 return (tls_get_addr_slow(dtvp, index, offset)); 4756 } 4757 4758 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4759 defined(__powerpc__) || defined(__riscv) 4760 4761 /* 4762 * Return pointer to allocated TLS block 4763 */ 4764 static void * 4765 get_tls_block_ptr(void *tcb, size_t tcbsize) 4766 { 4767 size_t extra_size, post_size, pre_size, tls_block_size; 4768 size_t tls_init_align; 4769 4770 tls_init_align = MAX(obj_main->tlsalign, 1); 4771 4772 /* Compute fragments sizes. */ 4773 extra_size = tcbsize - TLS_TCB_SIZE; 4774 post_size = calculate_tls_post_size(tls_init_align); 4775 tls_block_size = tcbsize + post_size; 4776 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4777 4778 return ((char *)tcb - pre_size - extra_size); 4779 } 4780 4781 /* 4782 * Allocate Static TLS using the Variant I method. 4783 * 4784 * For details on the layout, see lib/libc/gen/tls.c. 4785 * 4786 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4787 * it is based on tls_last_offset, and TLS offsets here are really TCB 4788 * offsets, whereas libc's tls_static_space is just the executable's static 4789 * TLS segment. 4790 */ 4791 void * 4792 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4793 { 4794 Obj_Entry *obj; 4795 char *tls_block; 4796 Elf_Addr *dtv, **tcb; 4797 Elf_Addr addr; 4798 Elf_Addr i; 4799 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4800 size_t tls_init_align; 4801 4802 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4803 return (oldtcb); 4804 4805 assert(tcbsize >= TLS_TCB_SIZE); 4806 maxalign = MAX(tcbalign, tls_static_max_align); 4807 tls_init_align = MAX(obj_main->tlsalign, 1); 4808 4809 /* Compute fragmets sizes. */ 4810 extra_size = tcbsize - TLS_TCB_SIZE; 4811 post_size = calculate_tls_post_size(tls_init_align); 4812 tls_block_size = tcbsize + post_size; 4813 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4814 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4815 4816 /* Allocate whole TLS block */ 4817 tls_block = malloc_aligned(tls_block_size, maxalign); 4818 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4819 4820 if (oldtcb != NULL) { 4821 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4822 tls_static_space); 4823 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4824 4825 /* Adjust the DTV. */ 4826 dtv = tcb[0]; 4827 for (i = 0; i < dtv[1]; i++) { 4828 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4829 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4830 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4831 } 4832 } 4833 } else { 4834 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4835 tcb[0] = dtv; 4836 dtv[0] = tls_dtv_generation; 4837 dtv[1] = tls_max_index; 4838 4839 for (obj = globallist_curr(objs); obj != NULL; 4840 obj = globallist_next(obj)) { 4841 if (obj->tlsoffset > 0) { 4842 addr = (Elf_Addr)tcb + obj->tlsoffset; 4843 if (obj->tlsinitsize > 0) 4844 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4845 if (obj->tlssize > obj->tlsinitsize) 4846 memset((void*)(addr + obj->tlsinitsize), 0, 4847 obj->tlssize - obj->tlsinitsize); 4848 dtv[obj->tlsindex + 1] = addr; 4849 } 4850 } 4851 } 4852 4853 return (tcb); 4854 } 4855 4856 void 4857 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4858 { 4859 Elf_Addr *dtv; 4860 Elf_Addr tlsstart, tlsend; 4861 size_t post_size; 4862 size_t dtvsize, i, tls_init_align; 4863 4864 assert(tcbsize >= TLS_TCB_SIZE); 4865 tls_init_align = MAX(obj_main->tlsalign, 1); 4866 4867 /* Compute fragments sizes. */ 4868 post_size = calculate_tls_post_size(tls_init_align); 4869 4870 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4871 tlsend = (Elf_Addr)tcb + tls_static_space; 4872 4873 dtv = *(Elf_Addr **)tcb; 4874 dtvsize = dtv[1]; 4875 for (i = 0; i < dtvsize; i++) { 4876 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4877 free((void*)dtv[i+2]); 4878 } 4879 } 4880 free(dtv); 4881 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4882 } 4883 4884 #endif 4885 4886 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4887 4888 /* 4889 * Allocate Static TLS using the Variant II method. 4890 */ 4891 void * 4892 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4893 { 4894 Obj_Entry *obj; 4895 size_t size, ralign; 4896 char *tls; 4897 Elf_Addr *dtv, *olddtv; 4898 Elf_Addr segbase, oldsegbase, addr; 4899 size_t i; 4900 4901 ralign = tcbalign; 4902 if (tls_static_max_align > ralign) 4903 ralign = tls_static_max_align; 4904 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4905 4906 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4907 tls = malloc_aligned(size, ralign); 4908 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4909 4910 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4911 ((Elf_Addr*)segbase)[0] = segbase; 4912 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4913 4914 dtv[0] = tls_dtv_generation; 4915 dtv[1] = tls_max_index; 4916 4917 if (oldtls) { 4918 /* 4919 * Copy the static TLS block over whole. 4920 */ 4921 oldsegbase = (Elf_Addr) oldtls; 4922 memcpy((void *)(segbase - tls_static_space), 4923 (const void *)(oldsegbase - tls_static_space), 4924 tls_static_space); 4925 4926 /* 4927 * If any dynamic TLS blocks have been created tls_get_addr(), 4928 * move them over. 4929 */ 4930 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4931 for (i = 0; i < olddtv[1]; i++) { 4932 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4933 dtv[i+2] = olddtv[i+2]; 4934 olddtv[i+2] = 0; 4935 } 4936 } 4937 4938 /* 4939 * We assume that this block was the one we created with 4940 * allocate_initial_tls(). 4941 */ 4942 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4943 } else { 4944 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4945 if (obj->marker || obj->tlsoffset == 0) 4946 continue; 4947 addr = segbase - obj->tlsoffset; 4948 memset((void*)(addr + obj->tlsinitsize), 4949 0, obj->tlssize - obj->tlsinitsize); 4950 if (obj->tlsinit) { 4951 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4952 obj->static_tls_copied = true; 4953 } 4954 dtv[obj->tlsindex + 1] = addr; 4955 } 4956 } 4957 4958 return (void*) segbase; 4959 } 4960 4961 void 4962 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4963 { 4964 Elf_Addr* dtv; 4965 size_t size, ralign; 4966 int dtvsize, i; 4967 Elf_Addr tlsstart, tlsend; 4968 4969 /* 4970 * Figure out the size of the initial TLS block so that we can 4971 * find stuff which ___tls_get_addr() allocated dynamically. 4972 */ 4973 ralign = tcbalign; 4974 if (tls_static_max_align > ralign) 4975 ralign = tls_static_max_align; 4976 size = round(tls_static_space, ralign); 4977 4978 dtv = ((Elf_Addr**)tls)[1]; 4979 dtvsize = dtv[1]; 4980 tlsend = (Elf_Addr) tls; 4981 tlsstart = tlsend - size; 4982 for (i = 0; i < dtvsize; i++) { 4983 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4984 free_aligned((void *)dtv[i + 2]); 4985 } 4986 } 4987 4988 free_aligned((void *)tlsstart); 4989 free((void*) dtv); 4990 } 4991 4992 #endif 4993 4994 /* 4995 * Allocate TLS block for module with given index. 4996 */ 4997 void * 4998 allocate_module_tls(int index) 4999 { 5000 Obj_Entry* obj; 5001 char* p; 5002 5003 TAILQ_FOREACH(obj, &obj_list, next) { 5004 if (obj->marker) 5005 continue; 5006 if (obj->tlsindex == index) 5007 break; 5008 } 5009 if (!obj) { 5010 _rtld_error("Can't find module with TLS index %d", index); 5011 rtld_die(); 5012 } 5013 5014 p = malloc_aligned(obj->tlssize, obj->tlsalign); 5015 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5016 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5017 5018 return p; 5019 } 5020 5021 bool 5022 allocate_tls_offset(Obj_Entry *obj) 5023 { 5024 size_t off; 5025 5026 if (obj->tls_done) 5027 return true; 5028 5029 if (obj->tlssize == 0) { 5030 obj->tls_done = true; 5031 return true; 5032 } 5033 5034 if (tls_last_offset == 0) 5035 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5036 else 5037 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5038 obj->tlssize, obj->tlsalign); 5039 5040 /* 5041 * If we have already fixed the size of the static TLS block, we 5042 * must stay within that size. When allocating the static TLS, we 5043 * leave a small amount of space spare to be used for dynamically 5044 * loading modules which use static TLS. 5045 */ 5046 if (tls_static_space != 0) { 5047 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5048 return false; 5049 } else if (obj->tlsalign > tls_static_max_align) { 5050 tls_static_max_align = obj->tlsalign; 5051 } 5052 5053 tls_last_offset = obj->tlsoffset = off; 5054 tls_last_size = obj->tlssize; 5055 obj->tls_done = true; 5056 5057 return true; 5058 } 5059 5060 void 5061 free_tls_offset(Obj_Entry *obj) 5062 { 5063 5064 /* 5065 * If we were the last thing to allocate out of the static TLS 5066 * block, we give our space back to the 'allocator'. This is a 5067 * simplistic workaround to allow libGL.so.1 to be loaded and 5068 * unloaded multiple times. 5069 */ 5070 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5071 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5072 tls_last_offset -= obj->tlssize; 5073 tls_last_size = 0; 5074 } 5075 } 5076 5077 void * 5078 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5079 { 5080 void *ret; 5081 RtldLockState lockstate; 5082 5083 wlock_acquire(rtld_bind_lock, &lockstate); 5084 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5085 tcbsize, tcbalign); 5086 lock_release(rtld_bind_lock, &lockstate); 5087 return (ret); 5088 } 5089 5090 void 5091 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5092 { 5093 RtldLockState lockstate; 5094 5095 wlock_acquire(rtld_bind_lock, &lockstate); 5096 free_tls(tcb, tcbsize, tcbalign); 5097 lock_release(rtld_bind_lock, &lockstate); 5098 } 5099 5100 static void 5101 object_add_name(Obj_Entry *obj, const char *name) 5102 { 5103 Name_Entry *entry; 5104 size_t len; 5105 5106 len = strlen(name); 5107 entry = malloc(sizeof(Name_Entry) + len); 5108 5109 if (entry != NULL) { 5110 strcpy(entry->name, name); 5111 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5112 } 5113 } 5114 5115 static int 5116 object_match_name(const Obj_Entry *obj, const char *name) 5117 { 5118 Name_Entry *entry; 5119 5120 STAILQ_FOREACH(entry, &obj->names, link) { 5121 if (strcmp(name, entry->name) == 0) 5122 return (1); 5123 } 5124 return (0); 5125 } 5126 5127 static Obj_Entry * 5128 locate_dependency(const Obj_Entry *obj, const char *name) 5129 { 5130 const Objlist_Entry *entry; 5131 const Needed_Entry *needed; 5132 5133 STAILQ_FOREACH(entry, &list_main, link) { 5134 if (object_match_name(entry->obj, name)) 5135 return entry->obj; 5136 } 5137 5138 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5139 if (strcmp(obj->strtab + needed->name, name) == 0 || 5140 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5141 /* 5142 * If there is DT_NEEDED for the name we are looking for, 5143 * we are all set. Note that object might not be found if 5144 * dependency was not loaded yet, so the function can 5145 * return NULL here. This is expected and handled 5146 * properly by the caller. 5147 */ 5148 return (needed->obj); 5149 } 5150 } 5151 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5152 obj->path, name); 5153 rtld_die(); 5154 } 5155 5156 static int 5157 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5158 const Elf_Vernaux *vna) 5159 { 5160 const Elf_Verdef *vd; 5161 const char *vername; 5162 5163 vername = refobj->strtab + vna->vna_name; 5164 vd = depobj->verdef; 5165 if (vd == NULL) { 5166 _rtld_error("%s: version %s required by %s not defined", 5167 depobj->path, vername, refobj->path); 5168 return (-1); 5169 } 5170 for (;;) { 5171 if (vd->vd_version != VER_DEF_CURRENT) { 5172 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5173 depobj->path, vd->vd_version); 5174 return (-1); 5175 } 5176 if (vna->vna_hash == vd->vd_hash) { 5177 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5178 ((const char *)vd + vd->vd_aux); 5179 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5180 return (0); 5181 } 5182 if (vd->vd_next == 0) 5183 break; 5184 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5185 } 5186 if (vna->vna_flags & VER_FLG_WEAK) 5187 return (0); 5188 _rtld_error("%s: version %s required by %s not found", 5189 depobj->path, vername, refobj->path); 5190 return (-1); 5191 } 5192 5193 static int 5194 rtld_verify_object_versions(Obj_Entry *obj) 5195 { 5196 const Elf_Verneed *vn; 5197 const Elf_Verdef *vd; 5198 const Elf_Verdaux *vda; 5199 const Elf_Vernaux *vna; 5200 const Obj_Entry *depobj; 5201 int maxvernum, vernum; 5202 5203 if (obj->ver_checked) 5204 return (0); 5205 obj->ver_checked = true; 5206 5207 maxvernum = 0; 5208 /* 5209 * Walk over defined and required version records and figure out 5210 * max index used by any of them. Do very basic sanity checking 5211 * while there. 5212 */ 5213 vn = obj->verneed; 5214 while (vn != NULL) { 5215 if (vn->vn_version != VER_NEED_CURRENT) { 5216 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5217 obj->path, vn->vn_version); 5218 return (-1); 5219 } 5220 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5221 for (;;) { 5222 vernum = VER_NEED_IDX(vna->vna_other); 5223 if (vernum > maxvernum) 5224 maxvernum = vernum; 5225 if (vna->vna_next == 0) 5226 break; 5227 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5228 } 5229 if (vn->vn_next == 0) 5230 break; 5231 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5232 } 5233 5234 vd = obj->verdef; 5235 while (vd != NULL) { 5236 if (vd->vd_version != VER_DEF_CURRENT) { 5237 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5238 obj->path, vd->vd_version); 5239 return (-1); 5240 } 5241 vernum = VER_DEF_IDX(vd->vd_ndx); 5242 if (vernum > maxvernum) 5243 maxvernum = vernum; 5244 if (vd->vd_next == 0) 5245 break; 5246 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5247 } 5248 5249 if (maxvernum == 0) 5250 return (0); 5251 5252 /* 5253 * Store version information in array indexable by version index. 5254 * Verify that object version requirements are satisfied along the 5255 * way. 5256 */ 5257 obj->vernum = maxvernum + 1; 5258 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5259 5260 vd = obj->verdef; 5261 while (vd != NULL) { 5262 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5263 vernum = VER_DEF_IDX(vd->vd_ndx); 5264 assert(vernum <= maxvernum); 5265 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5266 obj->vertab[vernum].hash = vd->vd_hash; 5267 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5268 obj->vertab[vernum].file = NULL; 5269 obj->vertab[vernum].flags = 0; 5270 } 5271 if (vd->vd_next == 0) 5272 break; 5273 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5274 } 5275 5276 vn = obj->verneed; 5277 while (vn != NULL) { 5278 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5279 if (depobj == NULL) 5280 return (-1); 5281 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5282 for (;;) { 5283 if (check_object_provided_version(obj, depobj, vna)) 5284 return (-1); 5285 vernum = VER_NEED_IDX(vna->vna_other); 5286 assert(vernum <= maxvernum); 5287 obj->vertab[vernum].hash = vna->vna_hash; 5288 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5289 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5290 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5291 VER_INFO_HIDDEN : 0; 5292 if (vna->vna_next == 0) 5293 break; 5294 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5295 } 5296 if (vn->vn_next == 0) 5297 break; 5298 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5299 } 5300 return 0; 5301 } 5302 5303 static int 5304 rtld_verify_versions(const Objlist *objlist) 5305 { 5306 Objlist_Entry *entry; 5307 int rc; 5308 5309 rc = 0; 5310 STAILQ_FOREACH(entry, objlist, link) { 5311 /* 5312 * Skip dummy objects or objects that have their version requirements 5313 * already checked. 5314 */ 5315 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5316 continue; 5317 if (rtld_verify_object_versions(entry->obj) == -1) { 5318 rc = -1; 5319 if (ld_tracing == NULL) 5320 break; 5321 } 5322 } 5323 if (rc == 0 || ld_tracing != NULL) 5324 rc = rtld_verify_object_versions(&obj_rtld); 5325 return rc; 5326 } 5327 5328 const Ver_Entry * 5329 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5330 { 5331 Elf_Versym vernum; 5332 5333 if (obj->vertab) { 5334 vernum = VER_NDX(obj->versyms[symnum]); 5335 if (vernum >= obj->vernum) { 5336 _rtld_error("%s: symbol %s has wrong verneed value %d", 5337 obj->path, obj->strtab + symnum, vernum); 5338 } else if (obj->vertab[vernum].hash != 0) { 5339 return &obj->vertab[vernum]; 5340 } 5341 } 5342 return NULL; 5343 } 5344 5345 int 5346 _rtld_get_stack_prot(void) 5347 { 5348 5349 return (stack_prot); 5350 } 5351 5352 int 5353 _rtld_is_dlopened(void *arg) 5354 { 5355 Obj_Entry *obj; 5356 RtldLockState lockstate; 5357 int res; 5358 5359 rlock_acquire(rtld_bind_lock, &lockstate); 5360 obj = dlcheck(arg); 5361 if (obj == NULL) 5362 obj = obj_from_addr(arg); 5363 if (obj == NULL) { 5364 _rtld_error("No shared object contains address"); 5365 lock_release(rtld_bind_lock, &lockstate); 5366 return (-1); 5367 } 5368 res = obj->dlopened ? 1 : 0; 5369 lock_release(rtld_bind_lock, &lockstate); 5370 return (res); 5371 } 5372 5373 static int 5374 obj_remap_relro(Obj_Entry *obj, int prot) 5375 { 5376 5377 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5378 prot) == -1) { 5379 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5380 obj->path, prot, rtld_strerror(errno)); 5381 return (-1); 5382 } 5383 return (0); 5384 } 5385 5386 static int 5387 obj_disable_relro(Obj_Entry *obj) 5388 { 5389 5390 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5391 } 5392 5393 static int 5394 obj_enforce_relro(Obj_Entry *obj) 5395 { 5396 5397 return (obj_remap_relro(obj, PROT_READ)); 5398 } 5399 5400 static void 5401 map_stacks_exec(RtldLockState *lockstate) 5402 { 5403 void (*thr_map_stacks_exec)(void); 5404 5405 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5406 return; 5407 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5408 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5409 if (thr_map_stacks_exec != NULL) { 5410 stack_prot |= PROT_EXEC; 5411 thr_map_stacks_exec(); 5412 } 5413 } 5414 5415 static void 5416 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5417 { 5418 Objlist_Entry *elm; 5419 Obj_Entry *obj; 5420 void (*distrib)(size_t, void *, size_t, size_t); 5421 5422 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5423 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5424 if (distrib == NULL) 5425 return; 5426 STAILQ_FOREACH(elm, list, link) { 5427 obj = elm->obj; 5428 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5429 continue; 5430 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5431 obj->tlssize); 5432 obj->static_tls_copied = true; 5433 } 5434 } 5435 5436 void 5437 symlook_init(SymLook *dst, const char *name) 5438 { 5439 5440 bzero(dst, sizeof(*dst)); 5441 dst->name = name; 5442 dst->hash = elf_hash(name); 5443 dst->hash_gnu = gnu_hash(name); 5444 } 5445 5446 static void 5447 symlook_init_from_req(SymLook *dst, const SymLook *src) 5448 { 5449 5450 dst->name = src->name; 5451 dst->hash = src->hash; 5452 dst->hash_gnu = src->hash_gnu; 5453 dst->ventry = src->ventry; 5454 dst->flags = src->flags; 5455 dst->defobj_out = NULL; 5456 dst->sym_out = NULL; 5457 dst->lockstate = src->lockstate; 5458 } 5459 5460 static int 5461 open_binary_fd(const char *argv0, bool search_in_path) 5462 { 5463 char *pathenv, *pe, binpath[PATH_MAX]; 5464 int fd; 5465 5466 if (search_in_path && strchr(argv0, '/') == NULL) { 5467 pathenv = getenv("PATH"); 5468 if (pathenv == NULL) { 5469 _rtld_error("-p and no PATH environment variable"); 5470 rtld_die(); 5471 } 5472 pathenv = strdup(pathenv); 5473 if (pathenv == NULL) { 5474 _rtld_error("Cannot allocate memory"); 5475 rtld_die(); 5476 } 5477 fd = -1; 5478 errno = ENOENT; 5479 while ((pe = strsep(&pathenv, ":")) != NULL) { 5480 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5481 sizeof(binpath)) 5482 continue; 5483 if (binpath[0] != '\0' && 5484 strlcat(binpath, "/", sizeof(binpath)) >= 5485 sizeof(binpath)) 5486 continue; 5487 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5488 sizeof(binpath)) 5489 continue; 5490 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5491 if (fd != -1 || errno != ENOENT) 5492 break; 5493 } 5494 free(pathenv); 5495 } else { 5496 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5497 } 5498 5499 if (fd == -1) { 5500 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5501 rtld_die(); 5502 } 5503 return (fd); 5504 } 5505 5506 /* 5507 * Parse a set of command-line arguments. 5508 */ 5509 static int 5510 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5511 { 5512 const char *arg; 5513 int fd, i, j, arglen; 5514 char opt; 5515 5516 dbg("Parsing command-line arguments"); 5517 *use_pathp = false; 5518 *fdp = -1; 5519 5520 for (i = 1; i < argc; i++ ) { 5521 arg = argv[i]; 5522 dbg("argv[%d]: '%s'", i, arg); 5523 5524 /* 5525 * rtld arguments end with an explicit "--" or with the first 5526 * non-prefixed argument. 5527 */ 5528 if (strcmp(arg, "--") == 0) { 5529 i++; 5530 break; 5531 } 5532 if (arg[0] != '-') 5533 break; 5534 5535 /* 5536 * All other arguments are single-character options that can 5537 * be combined, so we need to search through `arg` for them. 5538 */ 5539 arglen = strlen(arg); 5540 for (j = 1; j < arglen; j++) { 5541 opt = arg[j]; 5542 if (opt == 'h') { 5543 print_usage(argv[0]); 5544 _exit(0); 5545 } else if (opt == 'f') { 5546 /* 5547 * -f XX can be used to specify a descriptor for the 5548 * binary named at the command line (i.e., the later 5549 * argument will specify the process name but the 5550 * descriptor is what will actually be executed) 5551 */ 5552 if (j != arglen - 1) { 5553 /* -f must be the last option in, e.g., -abcf */ 5554 _rtld_error("Invalid options: %s", arg); 5555 rtld_die(); 5556 } 5557 i++; 5558 fd = parse_integer(argv[i]); 5559 if (fd == -1) { 5560 _rtld_error("Invalid file descriptor: '%s'", 5561 argv[i]); 5562 rtld_die(); 5563 } 5564 *fdp = fd; 5565 break; 5566 } else if (opt == 'p') { 5567 *use_pathp = true; 5568 } else { 5569 _rtld_error("Invalid argument: '%s'", arg); 5570 print_usage(argv[0]); 5571 rtld_die(); 5572 } 5573 } 5574 } 5575 5576 return (i); 5577 } 5578 5579 /* 5580 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5581 */ 5582 static int 5583 parse_integer(const char *str) 5584 { 5585 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5586 const char *orig; 5587 int n; 5588 char c; 5589 5590 orig = str; 5591 n = 0; 5592 for (c = *str; c != '\0'; c = *++str) { 5593 if (c < '0' || c > '9') 5594 return (-1); 5595 5596 n *= RADIX; 5597 n += c - '0'; 5598 } 5599 5600 /* Make sure we actually parsed something. */ 5601 if (str == orig) 5602 return (-1); 5603 return (n); 5604 } 5605 5606 static void 5607 print_usage(const char *argv0) 5608 { 5609 5610 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5611 "\n" 5612 "Options:\n" 5613 " -h Display this help message\n" 5614 " -p Search in PATH for named binary\n" 5615 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5616 " -- End of RTLD options\n" 5617 " <binary> Name of process to execute\n" 5618 " <args> Arguments to the executed process\n", argv0); 5619 } 5620 5621 /* 5622 * Overrides for libc_pic-provided functions. 5623 */ 5624 5625 int 5626 __getosreldate(void) 5627 { 5628 size_t len; 5629 int oid[2]; 5630 int error, osrel; 5631 5632 if (osreldate != 0) 5633 return (osreldate); 5634 5635 oid[0] = CTL_KERN; 5636 oid[1] = KERN_OSRELDATE; 5637 osrel = 0; 5638 len = sizeof(osrel); 5639 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5640 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5641 osreldate = osrel; 5642 return (osreldate); 5643 } 5644 5645 void 5646 exit(int status) 5647 { 5648 5649 _exit(status); 5650 } 5651 5652 void (*__cleanup)(void); 5653 int __isthreaded = 0; 5654 int _thread_autoinit_dummy_decl = 1; 5655 5656 /* 5657 * No unresolved symbols for rtld. 5658 */ 5659 void 5660 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5661 { 5662 } 5663 5664 const char * 5665 rtld_strerror(int errnum) 5666 { 5667 5668 if (errnum < 0 || errnum >= sys_nerr) 5669 return ("Unknown error"); 5670 return (sys_errlist[errnum]); 5671 } 5672 5673 /* 5674 * No ifunc relocations. 5675 */ 5676 void * 5677 memset(void *dest, int c, size_t len) 5678 { 5679 size_t i; 5680 5681 for (i = 0; i < len; i++) 5682 ((char *)dest)[i] = c; 5683 return (dest); 5684 } 5685 5686 void 5687 bzero(void *dest, size_t len) 5688 { 5689 size_t i; 5690 5691 for (i = 0; i < len; i++) 5692 ((char *)dest)[i] = 0; 5693 } 5694 5695 /* malloc */ 5696 void * 5697 malloc(size_t nbytes) 5698 { 5699 5700 return (__crt_malloc(nbytes)); 5701 } 5702 5703 void * 5704 calloc(size_t num, size_t size) 5705 { 5706 5707 return (__crt_calloc(num, size)); 5708 } 5709 5710 void 5711 free(void *cp) 5712 { 5713 5714 __crt_free(cp); 5715 } 5716 5717 void * 5718 realloc(void *cp, size_t nbytes) 5719 { 5720 5721 return (__crt_realloc(cp, nbytes)); 5722 } 5723