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