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