1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(void); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 78 /* Variables that cannot be static: */ 79 extern struct r_debug r_debug; /* For GDB */ 80 extern int _thread_autoinit_dummy_decl; 81 extern char* __progname; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static void digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path); 138 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 139 static int parse_integer(const char *); 140 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 141 static void print_usage(const char *argv0); 142 static void release_object(Obj_Entry *); 143 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 144 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 145 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 146 int flags, RtldLockState *lockstate); 147 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 148 RtldLockState *); 149 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 150 static int rtld_dirname(const char *, char *); 151 static int rtld_dirname_abs(const char *, char *); 152 static void *rtld_dlopen(const char *name, int fd, int mode); 153 static void rtld_exit(void); 154 static void rtld_nop_exit(void); 155 static char *search_library_path(const char *, const char *, const char *, 156 int *); 157 static char *search_library_pathfds(const char *, const char *, int *); 158 static const void **get_program_var_addr(const char *, RtldLockState *); 159 static void set_program_var(const char *, const void *); 160 static int symlook_default(SymLook *, const Obj_Entry *refobj); 161 static int symlook_global(SymLook *, DoneList *); 162 static void symlook_init_from_req(SymLook *, const SymLook *); 163 static int symlook_list(SymLook *, const Objlist *, DoneList *); 164 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 165 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 166 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 167 static void trace_loaded_objects(Obj_Entry *); 168 static void unlink_object(Obj_Entry *); 169 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 170 static void unref_dag(Obj_Entry *); 171 static void ref_dag(Obj_Entry *); 172 static char *origin_subst_one(Obj_Entry *, char *, const char *, 173 const char *, bool); 174 static char *origin_subst(Obj_Entry *, const char *); 175 static bool obj_resolve_origin(Obj_Entry *obj); 176 static void preinit_main(void); 177 static int rtld_verify_versions(const Objlist *); 178 static int rtld_verify_object_versions(Obj_Entry *); 179 static void object_add_name(Obj_Entry *, const char *); 180 static int object_match_name(const Obj_Entry *, const char *); 181 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 182 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 183 struct dl_phdr_info *phdr_info); 184 static uint32_t gnu_hash(const char *); 185 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 186 const unsigned long); 187 188 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 189 void _r_debug_postinit(struct link_map *) __noinline __exported; 190 191 int __sys_openat(int, const char *, int, ...); 192 193 /* 194 * Data declarations. 195 */ 196 static char *error_message; /* Message for dlerror(), or NULL */ 197 struct r_debug r_debug __exported; /* for GDB; */ 198 static bool libmap_disable; /* Disable libmap */ 199 static bool ld_loadfltr; /* Immediate filters processing */ 200 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 201 static bool trust; /* False for setuid and setgid programs */ 202 static bool dangerous_ld_env; /* True if environment variables have been 203 used to affect the libraries loaded */ 204 bool ld_bind_not; /* Disable PLT update */ 205 static char *ld_bind_now; /* Environment variable for immediate binding */ 206 static char *ld_debug; /* Environment variable for debugging */ 207 static char *ld_library_path; /* Environment variable for search path */ 208 static char *ld_library_dirs; /* Environment variable for library descriptors */ 209 static char *ld_preload; /* Environment variable for libraries to 210 load first */ 211 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 212 static const char *ld_tracing; /* Called from ldd to print libs */ 213 static char *ld_utrace; /* Use utrace() to log events. */ 214 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 215 static Obj_Entry *obj_main; /* The main program shared object */ 216 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 217 static unsigned int obj_count; /* Number of objects in obj_list */ 218 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 219 220 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 221 STAILQ_HEAD_INITIALIZER(list_global); 222 static Objlist list_main = /* Objects loaded at program startup */ 223 STAILQ_HEAD_INITIALIZER(list_main); 224 static Objlist list_fini = /* Objects needing fini() calls */ 225 STAILQ_HEAD_INITIALIZER(list_fini); 226 227 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 228 229 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 230 231 extern Elf_Dyn _DYNAMIC; 232 #pragma weak _DYNAMIC 233 234 int dlclose(void *) __exported; 235 char *dlerror(void) __exported; 236 void *dlopen(const char *, int) __exported; 237 void *fdlopen(int, int) __exported; 238 void *dlsym(void *, const char *) __exported; 239 dlfunc_t dlfunc(void *, const char *) __exported; 240 void *dlvsym(void *, const char *, const char *) __exported; 241 int dladdr(const void *, Dl_info *) __exported; 242 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 243 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 244 int dlinfo(void *, int , void *) __exported; 245 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 246 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 247 int _rtld_get_stack_prot(void) __exported; 248 int _rtld_is_dlopened(void *) __exported; 249 void _rtld_error(const char *, ...) __exported; 250 251 /* Only here to fix -Wmissing-prototypes warnings */ 252 int __getosreldate(void); 253 void __pthread_cxa_finalize(struct dl_phdr_info *a); 254 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 255 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 256 257 258 int npagesizes; 259 static int osreldate; 260 size_t *pagesizes; 261 262 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 263 static int max_stack_flags; 264 265 /* 266 * Global declarations normally provided by crt1. The dynamic linker is 267 * not built with crt1, so we have to provide them ourselves. 268 */ 269 char *__progname; 270 char **environ; 271 272 /* 273 * Used to pass argc, argv to init functions. 274 */ 275 int main_argc; 276 char **main_argv; 277 278 /* 279 * Globals to control TLS allocation. 280 */ 281 size_t tls_last_offset; /* Static TLS offset of last module */ 282 size_t tls_last_size; /* Static TLS size of last module */ 283 size_t tls_static_space; /* Static TLS space allocated */ 284 static size_t tls_static_max_align; 285 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 286 int tls_max_index = 1; /* Largest module index allocated */ 287 288 static bool ld_library_path_rpath = false; 289 290 /* 291 * Globals for path names, and such 292 */ 293 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 294 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 295 const char *ld_path_rtld = _PATH_RTLD; 296 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 297 const char *ld_env_prefix = LD_; 298 299 static void (*rtld_exit_ptr)(void); 300 301 /* 302 * Fill in a DoneList with an allocation large enough to hold all of 303 * the currently-loaded objects. Keep this as a macro since it calls 304 * alloca and we want that to occur within the scope of the caller. 305 */ 306 #define donelist_init(dlp) \ 307 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 308 assert((dlp)->objs != NULL), \ 309 (dlp)->num_alloc = obj_count, \ 310 (dlp)->num_used = 0) 311 312 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 313 if (ld_utrace != NULL) \ 314 ld_utrace_log(e, h, mb, ms, r, n); \ 315 } while (0) 316 317 static void 318 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 319 int refcnt, const char *name) 320 { 321 struct utrace_rtld ut; 322 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 323 324 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 325 ut.event = event; 326 ut.handle = handle; 327 ut.mapbase = mapbase; 328 ut.mapsize = mapsize; 329 ut.refcnt = refcnt; 330 bzero(ut.name, sizeof(ut.name)); 331 if (name) 332 strlcpy(ut.name, name, sizeof(ut.name)); 333 utrace(&ut, sizeof(ut)); 334 } 335 336 #ifdef RTLD_VARIANT_ENV_NAMES 337 /* 338 * construct the env variable based on the type of binary that's 339 * running. 340 */ 341 static inline const char * 342 _LD(const char *var) 343 { 344 static char buffer[128]; 345 346 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 347 strlcat(buffer, var, sizeof(buffer)); 348 return (buffer); 349 } 350 #else 351 #define _LD(x) LD_ x 352 #endif 353 354 /* 355 * Main entry point for dynamic linking. The first argument is the 356 * stack pointer. The stack is expected to be laid out as described 357 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 358 * Specifically, the stack pointer points to a word containing 359 * ARGC. Following that in the stack is a null-terminated sequence 360 * of pointers to argument strings. Then comes a null-terminated 361 * sequence of pointers to environment strings. Finally, there is a 362 * sequence of "auxiliary vector" entries. 363 * 364 * The second argument points to a place to store the dynamic linker's 365 * exit procedure pointer and the third to a place to store the main 366 * program's object. 367 * 368 * The return value is the main program's entry point. 369 */ 370 func_ptr_type 371 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 372 { 373 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 374 Objlist_Entry *entry; 375 Obj_Entry *last_interposer, *obj, *preload_tail; 376 const Elf_Phdr *phdr; 377 Objlist initlist; 378 RtldLockState lockstate; 379 struct stat st; 380 Elf_Addr *argcp; 381 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 382 const char *argv0; 383 caddr_t imgentry; 384 char buf[MAXPATHLEN]; 385 int argc, fd, i, phnum, rtld_argc; 386 bool dir_enable, explicit_fd, search_in_path; 387 388 /* 389 * On entry, the dynamic linker itself has not been relocated yet. 390 * Be very careful not to reference any global data until after 391 * init_rtld has returned. It is OK to reference file-scope statics 392 * and string constants, and to call static and global functions. 393 */ 394 395 /* Find the auxiliary vector on the stack. */ 396 argcp = sp; 397 argc = *sp++; 398 argv = (char **) sp; 399 sp += argc + 1; /* Skip over arguments and NULL terminator */ 400 env = (char **) sp; 401 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 402 ; 403 aux = (Elf_Auxinfo *) sp; 404 405 /* Digest the auxiliary vector. */ 406 for (i = 0; i < AT_COUNT; i++) 407 aux_info[i] = NULL; 408 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 409 if (auxp->a_type < AT_COUNT) 410 aux_info[auxp->a_type] = auxp; 411 } 412 413 /* Initialize and relocate ourselves. */ 414 assert(aux_info[AT_BASE] != NULL); 415 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 416 417 __progname = obj_rtld.path; 418 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 419 environ = env; 420 main_argc = argc; 421 main_argv = argv; 422 423 trust = !issetugid(); 424 425 md_abi_variant_hook(aux_info); 426 427 fd = -1; 428 if (aux_info[AT_EXECFD] != NULL) { 429 fd = aux_info[AT_EXECFD]->a_un.a_val; 430 } else { 431 assert(aux_info[AT_PHDR] != NULL); 432 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 433 if (phdr == obj_rtld.phdr) { 434 if (!trust) { 435 _rtld_error("Tainted process refusing to run binary %s", 436 argv0); 437 rtld_die(); 438 } 439 dbg("opening main program in direct exec mode"); 440 if (argc >= 2) { 441 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 442 argv0 = argv[rtld_argc]; 443 explicit_fd = (fd != -1); 444 if (!explicit_fd) 445 fd = open_binary_fd(argv0, search_in_path); 446 if (fstat(fd, &st) == -1) { 447 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 448 explicit_fd ? "user-provided descriptor" : argv0, 449 rtld_strerror(errno)); 450 rtld_die(); 451 } 452 453 /* 454 * Rough emulation of the permission checks done by 455 * execve(2), only Unix DACs are checked, ACLs are 456 * ignored. Preserve the semantic of disabling owner 457 * to execute if owner x bit is cleared, even if 458 * others x bit is enabled. 459 * mmap(2) does not allow to mmap with PROT_EXEC if 460 * binary' file comes from noexec mount. We cannot 461 * set a text reference on the binary. 462 */ 463 dir_enable = false; 464 if (st.st_uid == geteuid()) { 465 if ((st.st_mode & S_IXUSR) != 0) 466 dir_enable = true; 467 } else if (st.st_gid == getegid()) { 468 if ((st.st_mode & S_IXGRP) != 0) 469 dir_enable = true; 470 } else if ((st.st_mode & S_IXOTH) != 0) { 471 dir_enable = true; 472 } 473 if (!dir_enable) { 474 _rtld_error("No execute permission for binary %s", 475 argv0); 476 rtld_die(); 477 } 478 479 /* 480 * For direct exec mode, argv[0] is the interpreter 481 * name, we must remove it and shift arguments left 482 * before invoking binary main. Since stack layout 483 * places environment pointers and aux vectors right 484 * after the terminating NULL, we must shift 485 * environment and aux as well. 486 */ 487 main_argc = argc - rtld_argc; 488 for (i = 0; i <= main_argc; i++) 489 argv[i] = argv[i + rtld_argc]; 490 *argcp -= rtld_argc; 491 environ = env = envp = argv + main_argc + 1; 492 do { 493 *envp = *(envp + rtld_argc); 494 envp++; 495 } while (*envp != NULL); 496 aux = auxp = (Elf_Auxinfo *)envp; 497 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 498 for (;; auxp++, auxpf++) { 499 *auxp = *auxpf; 500 if (auxp->a_type == AT_NULL) 501 break; 502 } 503 } else { 504 _rtld_error("No binary"); 505 rtld_die(); 506 } 507 } 508 } 509 510 ld_bind_now = getenv(_LD("BIND_NOW")); 511 512 /* 513 * If the process is tainted, then we un-set the dangerous environment 514 * variables. The process will be marked as tainted until setuid(2) 515 * is called. If any child process calls setuid(2) we do not want any 516 * future processes to honor the potentially un-safe variables. 517 */ 518 if (!trust) { 519 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 520 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 521 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 522 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 523 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 524 _rtld_error("environment corrupt; aborting"); 525 rtld_die(); 526 } 527 } 528 ld_debug = getenv(_LD("DEBUG")); 529 if (ld_bind_now == NULL) 530 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 531 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 532 libmap_override = getenv(_LD("LIBMAP")); 533 ld_library_path = getenv(_LD("LIBRARY_PATH")); 534 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 535 ld_preload = getenv(_LD("PRELOAD")); 536 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 537 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 538 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 539 if (library_path_rpath != NULL) { 540 if (library_path_rpath[0] == 'y' || 541 library_path_rpath[0] == 'Y' || 542 library_path_rpath[0] == '1') 543 ld_library_path_rpath = true; 544 else 545 ld_library_path_rpath = false; 546 } 547 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 548 (ld_library_path != NULL) || (ld_preload != NULL) || 549 (ld_elf_hints_path != NULL) || ld_loadfltr; 550 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 551 ld_utrace = getenv(_LD("UTRACE")); 552 553 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 554 ld_elf_hints_path = ld_elf_hints_default; 555 556 if (ld_debug != NULL && *ld_debug != '\0') 557 debug = 1; 558 dbg("%s is initialized, base address = %p", __progname, 559 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 560 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 561 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 562 563 dbg("initializing thread locks"); 564 lockdflt_init(); 565 566 /* 567 * Load the main program, or process its program header if it is 568 * already loaded. 569 */ 570 if (fd != -1) { /* Load the main program. */ 571 dbg("loading main program"); 572 obj_main = map_object(fd, argv0, NULL); 573 close(fd); 574 if (obj_main == NULL) 575 rtld_die(); 576 max_stack_flags = obj_main->stack_flags; 577 } else { /* Main program already loaded. */ 578 dbg("processing main program's program header"); 579 assert(aux_info[AT_PHDR] != NULL); 580 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 581 assert(aux_info[AT_PHNUM] != NULL); 582 phnum = aux_info[AT_PHNUM]->a_un.a_val; 583 assert(aux_info[AT_PHENT] != NULL); 584 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 585 assert(aux_info[AT_ENTRY] != NULL); 586 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 587 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 588 rtld_die(); 589 } 590 591 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 592 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 593 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 594 if (kexecpath[0] == '/') 595 obj_main->path = kexecpath; 596 else if (getcwd(buf, sizeof(buf)) == NULL || 597 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 598 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 599 obj_main->path = xstrdup(argv0); 600 else 601 obj_main->path = xstrdup(buf); 602 } else { 603 dbg("No AT_EXECPATH or direct exec"); 604 obj_main->path = xstrdup(argv0); 605 } 606 dbg("obj_main path %s", obj_main->path); 607 obj_main->mainprog = true; 608 609 if (aux_info[AT_STACKPROT] != NULL && 610 aux_info[AT_STACKPROT]->a_un.a_val != 0) 611 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 612 613 #ifndef COMPAT_32BIT 614 /* 615 * Get the actual dynamic linker pathname from the executable if 616 * possible. (It should always be possible.) That ensures that 617 * gdb will find the right dynamic linker even if a non-standard 618 * one is being used. 619 */ 620 if (obj_main->interp != NULL && 621 strcmp(obj_main->interp, obj_rtld.path) != 0) { 622 free(obj_rtld.path); 623 obj_rtld.path = xstrdup(obj_main->interp); 624 __progname = obj_rtld.path; 625 } 626 #endif 627 628 digest_dynamic(obj_main, 0); 629 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 630 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 631 obj_main->dynsymcount); 632 633 linkmap_add(obj_main); 634 linkmap_add(&obj_rtld); 635 636 /* Link the main program into the list of objects. */ 637 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 638 obj_count++; 639 obj_loads++; 640 641 /* Initialize a fake symbol for resolving undefined weak references. */ 642 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 643 sym_zero.st_shndx = SHN_UNDEF; 644 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 645 646 if (!libmap_disable) 647 libmap_disable = (bool)lm_init(libmap_override); 648 649 dbg("loading LD_PRELOAD libraries"); 650 if (load_preload_objects() == -1) 651 rtld_die(); 652 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 653 654 dbg("loading needed objects"); 655 if (load_needed_objects(obj_main, 0) == -1) 656 rtld_die(); 657 658 /* Make a list of all objects loaded at startup. */ 659 last_interposer = obj_main; 660 TAILQ_FOREACH(obj, &obj_list, next) { 661 if (obj->marker) 662 continue; 663 if (obj->z_interpose && obj != obj_main) { 664 objlist_put_after(&list_main, last_interposer, obj); 665 last_interposer = obj; 666 } else { 667 objlist_push_tail(&list_main, obj); 668 } 669 obj->refcount++; 670 } 671 672 dbg("checking for required versions"); 673 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 674 rtld_die(); 675 676 if (ld_tracing) { /* We're done */ 677 trace_loaded_objects(obj_main); 678 exit(0); 679 } 680 681 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 682 dump_relocations(obj_main); 683 exit (0); 684 } 685 686 /* 687 * Processing tls relocations requires having the tls offsets 688 * initialized. Prepare offsets before starting initial 689 * relocation processing. 690 */ 691 dbg("initializing initial thread local storage offsets"); 692 STAILQ_FOREACH(entry, &list_main, link) { 693 /* 694 * Allocate all the initial objects out of the static TLS 695 * block even if they didn't ask for it. 696 */ 697 allocate_tls_offset(entry->obj); 698 } 699 700 if (relocate_objects(obj_main, 701 ld_bind_now != NULL && *ld_bind_now != '\0', 702 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 703 rtld_die(); 704 705 dbg("doing copy relocations"); 706 if (do_copy_relocations(obj_main) == -1) 707 rtld_die(); 708 709 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 710 dump_relocations(obj_main); 711 exit (0); 712 } 713 714 ifunc_init(aux); 715 716 /* 717 * Setup TLS for main thread. This must be done after the 718 * relocations are processed, since tls initialization section 719 * might be the subject for relocations. 720 */ 721 dbg("initializing initial thread local storage"); 722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 723 724 dbg("initializing key program variables"); 725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 726 set_program_var("environ", env); 727 set_program_var("__elf_aux_vector", aux); 728 729 /* Make a list of init functions to call. */ 730 objlist_init(&initlist); 731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 732 preload_tail, &initlist); 733 734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 735 736 map_stacks_exec(NULL); 737 738 if (!obj_main->crt_no_init) { 739 /* 740 * Make sure we don't call the main program's init and fini 741 * functions for binaries linked with old crt1 which calls 742 * _init itself. 743 */ 744 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 745 obj_main->preinit_array = obj_main->init_array = 746 obj_main->fini_array = (Elf_Addr)NULL; 747 } 748 749 /* 750 * Execute MD initializers required before we call the objects' 751 * init functions. 752 */ 753 pre_init(); 754 755 wlock_acquire(rtld_bind_lock, &lockstate); 756 757 dbg("resolving ifuncs"); 758 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 759 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 760 rtld_die(); 761 762 rtld_exit_ptr = rtld_exit; 763 if (obj_main->crt_no_init) 764 preinit_main(); 765 objlist_call_init(&initlist, &lockstate); 766 _r_debug_postinit(&obj_main->linkmap); 767 objlist_clear(&initlist); 768 dbg("loading filtees"); 769 TAILQ_FOREACH(obj, &obj_list, next) { 770 if (obj->marker) 771 continue; 772 if (ld_loadfltr || obj->z_loadfltr) 773 load_filtees(obj, 0, &lockstate); 774 } 775 776 dbg("enforcing main obj relro"); 777 if (obj_enforce_relro(obj_main) == -1) 778 rtld_die(); 779 780 lock_release(rtld_bind_lock, &lockstate); 781 782 dbg("transferring control to program entry point = %p", obj_main->entry); 783 784 /* Return the exit procedure and the program entry point. */ 785 *exit_proc = rtld_exit_ptr; 786 *objp = obj_main; 787 return (func_ptr_type) obj_main->entry; 788 } 789 790 void * 791 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 792 { 793 void *ptr; 794 Elf_Addr target; 795 796 ptr = (void *)make_function_pointer(def, obj); 797 target = call_ifunc_resolver(ptr); 798 return ((void *)target); 799 } 800 801 /* 802 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 803 * Changes to this function should be applied there as well. 804 */ 805 Elf_Addr 806 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 807 { 808 const Elf_Rel *rel; 809 const Elf_Sym *def; 810 const Obj_Entry *defobj; 811 Elf_Addr *where; 812 Elf_Addr target; 813 RtldLockState lockstate; 814 815 rlock_acquire(rtld_bind_lock, &lockstate); 816 if (sigsetjmp(lockstate.env, 0) != 0) 817 lock_upgrade(rtld_bind_lock, &lockstate); 818 if (obj->pltrel) 819 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 820 else 821 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 822 823 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 824 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 825 NULL, &lockstate); 826 if (def == NULL) 827 rtld_die(); 828 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 829 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 830 else 831 target = (Elf_Addr)(defobj->relocbase + def->st_value); 832 833 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 834 defobj->strtab + def->st_name, basename(obj->path), 835 (void *)target, basename(defobj->path)); 836 837 /* 838 * Write the new contents for the jmpslot. Note that depending on 839 * architecture, the value which we need to return back to the 840 * lazy binding trampoline may or may not be the target 841 * address. The value returned from reloc_jmpslot() is the value 842 * that the trampoline needs. 843 */ 844 target = reloc_jmpslot(where, target, defobj, obj, rel); 845 lock_release(rtld_bind_lock, &lockstate); 846 return target; 847 } 848 849 /* 850 * Error reporting function. Use it like printf. If formats the message 851 * into a buffer, and sets things up so that the next call to dlerror() 852 * will return the message. 853 */ 854 void 855 _rtld_error(const char *fmt, ...) 856 { 857 static char buf[512]; 858 va_list ap; 859 860 va_start(ap, fmt); 861 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 862 error_message = buf; 863 va_end(ap); 864 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 865 } 866 867 /* 868 * Return a dynamically-allocated copy of the current error message, if any. 869 */ 870 static char * 871 errmsg_save(void) 872 { 873 return error_message == NULL ? NULL : xstrdup(error_message); 874 } 875 876 /* 877 * Restore the current error message from a copy which was previously saved 878 * by errmsg_save(). The copy is freed. 879 */ 880 static void 881 errmsg_restore(char *saved_msg) 882 { 883 if (saved_msg == NULL) 884 error_message = NULL; 885 else { 886 _rtld_error("%s", saved_msg); 887 free(saved_msg); 888 } 889 } 890 891 static const char * 892 basename(const char *name) 893 { 894 const char *p = strrchr(name, '/'); 895 return p != NULL ? p + 1 : name; 896 } 897 898 static struct utsname uts; 899 900 static char * 901 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 902 const char *subst, bool may_free) 903 { 904 char *p, *p1, *res, *resp; 905 int subst_len, kw_len, subst_count, old_len, new_len; 906 907 kw_len = strlen(kw); 908 909 /* 910 * First, count the number of the keyword occurrences, to 911 * preallocate the final string. 912 */ 913 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 914 p1 = strstr(p, kw); 915 if (p1 == NULL) 916 break; 917 } 918 919 /* 920 * If the keyword is not found, just return. 921 * 922 * Return non-substituted string if resolution failed. We 923 * cannot do anything more reasonable, the failure mode of the 924 * caller is unresolved library anyway. 925 */ 926 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 927 return (may_free ? real : xstrdup(real)); 928 if (obj != NULL) 929 subst = obj->origin_path; 930 931 /* 932 * There is indeed something to substitute. Calculate the 933 * length of the resulting string, and allocate it. 934 */ 935 subst_len = strlen(subst); 936 old_len = strlen(real); 937 new_len = old_len + (subst_len - kw_len) * subst_count; 938 res = xmalloc(new_len + 1); 939 940 /* 941 * Now, execute the substitution loop. 942 */ 943 for (p = real, resp = res, *resp = '\0';;) { 944 p1 = strstr(p, kw); 945 if (p1 != NULL) { 946 /* Copy the prefix before keyword. */ 947 memcpy(resp, p, p1 - p); 948 resp += p1 - p; 949 /* Keyword replacement. */ 950 memcpy(resp, subst, subst_len); 951 resp += subst_len; 952 *resp = '\0'; 953 p = p1 + kw_len; 954 } else 955 break; 956 } 957 958 /* Copy to the end of string and finish. */ 959 strcat(resp, p); 960 if (may_free) 961 free(real); 962 return (res); 963 } 964 965 static char * 966 origin_subst(Obj_Entry *obj, const char *real) 967 { 968 char *res1, *res2, *res3, *res4; 969 970 if (obj == NULL || !trust) 971 return (xstrdup(real)); 972 if (uts.sysname[0] == '\0') { 973 if (uname(&uts) != 0) { 974 _rtld_error("utsname failed: %d", errno); 975 return (NULL); 976 } 977 } 978 /* __DECONST is safe here since without may_free real is unchanged */ 979 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 980 false); 981 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 982 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 983 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 984 return (res4); 985 } 986 987 void 988 rtld_die(void) 989 { 990 const char *msg = dlerror(); 991 992 if (msg == NULL) 993 msg = "Fatal error"; 994 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 995 rtld_fdputstr(STDERR_FILENO, msg); 996 rtld_fdputchar(STDERR_FILENO, '\n'); 997 _exit(1); 998 } 999 1000 /* 1001 * Process a shared object's DYNAMIC section, and save the important 1002 * information in its Obj_Entry structure. 1003 */ 1004 static void 1005 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1006 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1007 { 1008 const Elf_Dyn *dynp; 1009 Needed_Entry **needed_tail = &obj->needed; 1010 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1011 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1012 const Elf_Hashelt *hashtab; 1013 const Elf32_Word *hashval; 1014 Elf32_Word bkt, nmaskwords; 1015 int bloom_size32; 1016 int plttype = DT_REL; 1017 1018 *dyn_rpath = NULL; 1019 *dyn_soname = NULL; 1020 *dyn_runpath = NULL; 1021 1022 obj->bind_now = false; 1023 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1024 switch (dynp->d_tag) { 1025 1026 case DT_REL: 1027 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1028 break; 1029 1030 case DT_RELSZ: 1031 obj->relsize = dynp->d_un.d_val; 1032 break; 1033 1034 case DT_RELENT: 1035 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1036 break; 1037 1038 case DT_JMPREL: 1039 obj->pltrel = (const Elf_Rel *) 1040 (obj->relocbase + dynp->d_un.d_ptr); 1041 break; 1042 1043 case DT_PLTRELSZ: 1044 obj->pltrelsize = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_RELA: 1048 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1049 break; 1050 1051 case DT_RELASZ: 1052 obj->relasize = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_RELAENT: 1056 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1057 break; 1058 1059 case DT_PLTREL: 1060 plttype = dynp->d_un.d_val; 1061 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1062 break; 1063 1064 case DT_SYMTAB: 1065 obj->symtab = (const Elf_Sym *) 1066 (obj->relocbase + dynp->d_un.d_ptr); 1067 break; 1068 1069 case DT_SYMENT: 1070 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1071 break; 1072 1073 case DT_STRTAB: 1074 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1075 break; 1076 1077 case DT_STRSZ: 1078 obj->strsize = dynp->d_un.d_val; 1079 break; 1080 1081 case DT_VERNEED: 1082 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1083 dynp->d_un.d_val); 1084 break; 1085 1086 case DT_VERNEEDNUM: 1087 obj->verneednum = dynp->d_un.d_val; 1088 break; 1089 1090 case DT_VERDEF: 1091 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1092 dynp->d_un.d_val); 1093 break; 1094 1095 case DT_VERDEFNUM: 1096 obj->verdefnum = dynp->d_un.d_val; 1097 break; 1098 1099 case DT_VERSYM: 1100 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1101 dynp->d_un.d_val); 1102 break; 1103 1104 case DT_HASH: 1105 { 1106 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1107 dynp->d_un.d_ptr); 1108 obj->nbuckets = hashtab[0]; 1109 obj->nchains = hashtab[1]; 1110 obj->buckets = hashtab + 2; 1111 obj->chains = obj->buckets + obj->nbuckets; 1112 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1113 obj->buckets != NULL; 1114 } 1115 break; 1116 1117 case DT_GNU_HASH: 1118 { 1119 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1120 dynp->d_un.d_ptr); 1121 obj->nbuckets_gnu = hashtab[0]; 1122 obj->symndx_gnu = hashtab[1]; 1123 nmaskwords = hashtab[2]; 1124 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1125 obj->maskwords_bm_gnu = nmaskwords - 1; 1126 obj->shift2_gnu = hashtab[3]; 1127 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1128 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1129 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1130 obj->symndx_gnu; 1131 /* Number of bitmask words is required to be power of 2 */ 1132 obj->valid_hash_gnu = powerof2(nmaskwords) && 1133 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1134 } 1135 break; 1136 1137 case DT_NEEDED: 1138 if (!obj->rtld) { 1139 Needed_Entry *nep = NEW(Needed_Entry); 1140 nep->name = dynp->d_un.d_val; 1141 nep->obj = NULL; 1142 nep->next = NULL; 1143 1144 *needed_tail = nep; 1145 needed_tail = &nep->next; 1146 } 1147 break; 1148 1149 case DT_FILTER: 1150 if (!obj->rtld) { 1151 Needed_Entry *nep = NEW(Needed_Entry); 1152 nep->name = dynp->d_un.d_val; 1153 nep->obj = NULL; 1154 nep->next = NULL; 1155 1156 *needed_filtees_tail = nep; 1157 needed_filtees_tail = &nep->next; 1158 } 1159 break; 1160 1161 case DT_AUXILIARY: 1162 if (!obj->rtld) { 1163 Needed_Entry *nep = NEW(Needed_Entry); 1164 nep->name = dynp->d_un.d_val; 1165 nep->obj = NULL; 1166 nep->next = NULL; 1167 1168 *needed_aux_filtees_tail = nep; 1169 needed_aux_filtees_tail = &nep->next; 1170 } 1171 break; 1172 1173 case DT_PLTGOT: 1174 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1175 break; 1176 1177 case DT_TEXTREL: 1178 obj->textrel = true; 1179 break; 1180 1181 case DT_SYMBOLIC: 1182 obj->symbolic = true; 1183 break; 1184 1185 case DT_RPATH: 1186 /* 1187 * We have to wait until later to process this, because we 1188 * might not have gotten the address of the string table yet. 1189 */ 1190 *dyn_rpath = dynp; 1191 break; 1192 1193 case DT_SONAME: 1194 *dyn_soname = dynp; 1195 break; 1196 1197 case DT_RUNPATH: 1198 *dyn_runpath = dynp; 1199 break; 1200 1201 case DT_INIT: 1202 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1203 break; 1204 1205 case DT_PREINIT_ARRAY: 1206 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1207 break; 1208 1209 case DT_PREINIT_ARRAYSZ: 1210 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1211 break; 1212 1213 case DT_INIT_ARRAY: 1214 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1215 break; 1216 1217 case DT_INIT_ARRAYSZ: 1218 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1219 break; 1220 1221 case DT_FINI: 1222 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1223 break; 1224 1225 case DT_FINI_ARRAY: 1226 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1227 break; 1228 1229 case DT_FINI_ARRAYSZ: 1230 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1231 break; 1232 1233 /* 1234 * Don't process DT_DEBUG on MIPS as the dynamic section 1235 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1236 */ 1237 1238 #ifndef __mips__ 1239 case DT_DEBUG: 1240 if (!early) 1241 dbg("Filling in DT_DEBUG entry"); 1242 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1243 break; 1244 #endif 1245 1246 case DT_FLAGS: 1247 if (dynp->d_un.d_val & DF_ORIGIN) 1248 obj->z_origin = true; 1249 if (dynp->d_un.d_val & DF_SYMBOLIC) 1250 obj->symbolic = true; 1251 if (dynp->d_un.d_val & DF_TEXTREL) 1252 obj->textrel = true; 1253 if (dynp->d_un.d_val & DF_BIND_NOW) 1254 obj->bind_now = true; 1255 if (dynp->d_un.d_val & DF_STATIC_TLS) 1256 obj->static_tls = true; 1257 break; 1258 #ifdef __mips__ 1259 case DT_MIPS_LOCAL_GOTNO: 1260 obj->local_gotno = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_SYMTABNO: 1264 obj->symtabno = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_MIPS_GOTSYM: 1268 obj->gotsym = dynp->d_un.d_val; 1269 break; 1270 1271 case DT_MIPS_RLD_MAP: 1272 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1273 break; 1274 1275 case DT_MIPS_RLD_MAP_REL: 1276 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1277 // section relative to the address of the tag itself. 1278 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1279 (Elf_Addr) &r_debug; 1280 break; 1281 1282 case DT_MIPS_PLTGOT: 1283 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1284 dynp->d_un.d_ptr); 1285 break; 1286 1287 #endif 1288 1289 #ifdef __powerpc__ 1290 #ifdef __powerpc64__ 1291 case DT_PPC64_GLINK: 1292 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1293 break; 1294 #else 1295 case DT_PPC_GOT: 1296 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1297 break; 1298 #endif 1299 #endif 1300 1301 case DT_FLAGS_1: 1302 if (dynp->d_un.d_val & DF_1_NOOPEN) 1303 obj->z_noopen = true; 1304 if (dynp->d_un.d_val & DF_1_ORIGIN) 1305 obj->z_origin = true; 1306 if (dynp->d_un.d_val & DF_1_GLOBAL) 1307 obj->z_global = true; 1308 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1309 obj->bind_now = true; 1310 if (dynp->d_un.d_val & DF_1_NODELETE) 1311 obj->z_nodelete = true; 1312 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1313 obj->z_loadfltr = true; 1314 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1315 obj->z_interpose = true; 1316 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1317 obj->z_nodeflib = true; 1318 break; 1319 1320 default: 1321 if (!early) { 1322 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1323 (long)dynp->d_tag); 1324 } 1325 break; 1326 } 1327 } 1328 1329 obj->traced = false; 1330 1331 if (plttype == DT_RELA) { 1332 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1333 obj->pltrel = NULL; 1334 obj->pltrelasize = obj->pltrelsize; 1335 obj->pltrelsize = 0; 1336 } 1337 1338 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1339 if (obj->valid_hash_sysv) 1340 obj->dynsymcount = obj->nchains; 1341 else if (obj->valid_hash_gnu) { 1342 obj->dynsymcount = 0; 1343 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1344 if (obj->buckets_gnu[bkt] == 0) 1345 continue; 1346 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1347 do 1348 obj->dynsymcount++; 1349 while ((*hashval++ & 1u) == 0); 1350 } 1351 obj->dynsymcount += obj->symndx_gnu; 1352 } 1353 } 1354 1355 static bool 1356 obj_resolve_origin(Obj_Entry *obj) 1357 { 1358 1359 if (obj->origin_path != NULL) 1360 return (true); 1361 obj->origin_path = xmalloc(PATH_MAX); 1362 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1363 } 1364 1365 static void 1366 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1367 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1368 { 1369 1370 if (obj->z_origin && !obj_resolve_origin(obj)) 1371 rtld_die(); 1372 1373 if (dyn_runpath != NULL) { 1374 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1375 obj->runpath = origin_subst(obj, obj->runpath); 1376 } else if (dyn_rpath != NULL) { 1377 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1378 obj->rpath = origin_subst(obj, obj->rpath); 1379 } 1380 if (dyn_soname != NULL) 1381 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1382 } 1383 1384 static void 1385 digest_dynamic(Obj_Entry *obj, int early) 1386 { 1387 const Elf_Dyn *dyn_rpath; 1388 const Elf_Dyn *dyn_soname; 1389 const Elf_Dyn *dyn_runpath; 1390 1391 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1392 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1393 } 1394 1395 /* 1396 * Process a shared object's program header. This is used only for the 1397 * main program, when the kernel has already loaded the main program 1398 * into memory before calling the dynamic linker. It creates and 1399 * returns an Obj_Entry structure. 1400 */ 1401 static Obj_Entry * 1402 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1403 { 1404 Obj_Entry *obj; 1405 const Elf_Phdr *phlimit = phdr + phnum; 1406 const Elf_Phdr *ph; 1407 Elf_Addr note_start, note_end; 1408 int nsegs = 0; 1409 1410 obj = obj_new(); 1411 for (ph = phdr; ph < phlimit; ph++) { 1412 if (ph->p_type != PT_PHDR) 1413 continue; 1414 1415 obj->phdr = phdr; 1416 obj->phsize = ph->p_memsz; 1417 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1418 break; 1419 } 1420 1421 obj->stack_flags = PF_X | PF_R | PF_W; 1422 1423 for (ph = phdr; ph < phlimit; ph++) { 1424 switch (ph->p_type) { 1425 1426 case PT_INTERP: 1427 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1428 break; 1429 1430 case PT_LOAD: 1431 if (nsegs == 0) { /* First load segment */ 1432 obj->vaddrbase = trunc_page(ph->p_vaddr); 1433 obj->mapbase = obj->vaddrbase + obj->relocbase; 1434 } else { /* Last load segment */ 1435 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1436 obj->vaddrbase; 1437 } 1438 nsegs++; 1439 break; 1440 1441 case PT_DYNAMIC: 1442 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1443 break; 1444 1445 case PT_TLS: 1446 obj->tlsindex = 1; 1447 obj->tlssize = ph->p_memsz; 1448 obj->tlsalign = ph->p_align; 1449 obj->tlsinitsize = ph->p_filesz; 1450 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1451 break; 1452 1453 case PT_GNU_STACK: 1454 obj->stack_flags = ph->p_flags; 1455 break; 1456 1457 case PT_GNU_RELRO: 1458 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1459 obj->relro_size = round_page(ph->p_memsz); 1460 break; 1461 1462 case PT_NOTE: 1463 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1464 note_end = note_start + ph->p_filesz; 1465 digest_notes(obj, note_start, note_end); 1466 break; 1467 } 1468 } 1469 if (nsegs < 1) { 1470 _rtld_error("%s: too few PT_LOAD segments", path); 1471 return NULL; 1472 } 1473 1474 obj->entry = entry; 1475 return obj; 1476 } 1477 1478 void 1479 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1480 { 1481 const Elf_Note *note; 1482 const char *note_name; 1483 uintptr_t p; 1484 1485 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1486 note = (const Elf_Note *)((const char *)(note + 1) + 1487 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1488 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1489 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1490 note->n_descsz != sizeof(int32_t)) 1491 continue; 1492 if (note->n_type != NT_FREEBSD_ABI_TAG && 1493 note->n_type != NT_FREEBSD_FEATURE_CTL && 1494 note->n_type != NT_FREEBSD_NOINIT_TAG) 1495 continue; 1496 note_name = (const char *)(note + 1); 1497 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1498 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1499 continue; 1500 switch (note->n_type) { 1501 case NT_FREEBSD_ABI_TAG: 1502 /* FreeBSD osrel note */ 1503 p = (uintptr_t)(note + 1); 1504 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1505 obj->osrel = *(const int32_t *)(p); 1506 dbg("note osrel %d", obj->osrel); 1507 break; 1508 case NT_FREEBSD_FEATURE_CTL: 1509 /* FreeBSD ABI feature control note */ 1510 p = (uintptr_t)(note + 1); 1511 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1512 obj->fctl0 = *(const uint32_t *)(p); 1513 dbg("note fctl0 %#x", obj->fctl0); 1514 break; 1515 case NT_FREEBSD_NOINIT_TAG: 1516 /* FreeBSD 'crt does not call init' note */ 1517 obj->crt_no_init = true; 1518 dbg("note crt_no_init"); 1519 break; 1520 } 1521 } 1522 } 1523 1524 static Obj_Entry * 1525 dlcheck(void *handle) 1526 { 1527 Obj_Entry *obj; 1528 1529 TAILQ_FOREACH(obj, &obj_list, next) { 1530 if (obj == (Obj_Entry *) handle) 1531 break; 1532 } 1533 1534 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1535 _rtld_error("Invalid shared object handle %p", handle); 1536 return NULL; 1537 } 1538 return obj; 1539 } 1540 1541 /* 1542 * If the given object is already in the donelist, return true. Otherwise 1543 * add the object to the list and return false. 1544 */ 1545 static bool 1546 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1547 { 1548 unsigned int i; 1549 1550 for (i = 0; i < dlp->num_used; i++) 1551 if (dlp->objs[i] == obj) 1552 return true; 1553 /* 1554 * Our donelist allocation should always be sufficient. But if 1555 * our threads locking isn't working properly, more shared objects 1556 * could have been loaded since we allocated the list. That should 1557 * never happen, but we'll handle it properly just in case it does. 1558 */ 1559 if (dlp->num_used < dlp->num_alloc) 1560 dlp->objs[dlp->num_used++] = obj; 1561 return false; 1562 } 1563 1564 /* 1565 * Hash function for symbol table lookup. Don't even think about changing 1566 * this. It is specified by the System V ABI. 1567 */ 1568 unsigned long 1569 elf_hash(const char *name) 1570 { 1571 const unsigned char *p = (const unsigned char *) name; 1572 unsigned long h = 0; 1573 unsigned long g; 1574 1575 while (*p != '\0') { 1576 h = (h << 4) + *p++; 1577 if ((g = h & 0xf0000000) != 0) 1578 h ^= g >> 24; 1579 h &= ~g; 1580 } 1581 return h; 1582 } 1583 1584 /* 1585 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1586 * unsigned in case it's implemented with a wider type. 1587 */ 1588 static uint32_t 1589 gnu_hash(const char *s) 1590 { 1591 uint32_t h; 1592 unsigned char c; 1593 1594 h = 5381; 1595 for (c = *s; c != '\0'; c = *++s) 1596 h = h * 33 + c; 1597 return (h & 0xffffffff); 1598 } 1599 1600 1601 /* 1602 * Find the library with the given name, and return its full pathname. 1603 * The returned string is dynamically allocated. Generates an error 1604 * message and returns NULL if the library cannot be found. 1605 * 1606 * If the second argument is non-NULL, then it refers to an already- 1607 * loaded shared object, whose library search path will be searched. 1608 * 1609 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1610 * descriptor (which is close-on-exec) will be passed out via the third 1611 * argument. 1612 * 1613 * The search order is: 1614 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1615 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1616 * LD_LIBRARY_PATH 1617 * DT_RUNPATH in the referencing file 1618 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1619 * from list) 1620 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1621 * 1622 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1623 */ 1624 static char * 1625 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1626 { 1627 char *pathname, *refobj_path; 1628 const char *name; 1629 bool nodeflib, objgiven; 1630 1631 objgiven = refobj != NULL; 1632 1633 if (libmap_disable || !objgiven || 1634 (name = lm_find(refobj->path, xname)) == NULL) 1635 name = xname; 1636 1637 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1638 if (name[0] != '/' && !trust) { 1639 _rtld_error("Absolute pathname required " 1640 "for shared object \"%s\"", name); 1641 return (NULL); 1642 } 1643 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1644 __DECONST(char *, name))); 1645 } 1646 1647 dbg(" Searching for \"%s\"", name); 1648 refobj_path = objgiven ? refobj->path : NULL; 1649 1650 /* 1651 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1652 * back to pre-conforming behaviour if user requested so with 1653 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1654 * nodeflib. 1655 */ 1656 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1657 pathname = search_library_path(name, ld_library_path, 1658 refobj_path, fdp); 1659 if (pathname != NULL) 1660 return (pathname); 1661 if (refobj != NULL) { 1662 pathname = search_library_path(name, refobj->rpath, 1663 refobj_path, fdp); 1664 if (pathname != NULL) 1665 return (pathname); 1666 } 1667 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1668 if (pathname != NULL) 1669 return (pathname); 1670 pathname = search_library_path(name, gethints(false), 1671 refobj_path, fdp); 1672 if (pathname != NULL) 1673 return (pathname); 1674 pathname = search_library_path(name, ld_standard_library_path, 1675 refobj_path, fdp); 1676 if (pathname != NULL) 1677 return (pathname); 1678 } else { 1679 nodeflib = objgiven ? refobj->z_nodeflib : false; 1680 if (objgiven) { 1681 pathname = search_library_path(name, refobj->rpath, 1682 refobj->path, fdp); 1683 if (pathname != NULL) 1684 return (pathname); 1685 } 1686 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1687 pathname = search_library_path(name, obj_main->rpath, 1688 refobj_path, fdp); 1689 if (pathname != NULL) 1690 return (pathname); 1691 } 1692 pathname = search_library_path(name, ld_library_path, 1693 refobj_path, fdp); 1694 if (pathname != NULL) 1695 return (pathname); 1696 if (objgiven) { 1697 pathname = search_library_path(name, refobj->runpath, 1698 refobj_path, fdp); 1699 if (pathname != NULL) 1700 return (pathname); 1701 } 1702 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1703 if (pathname != NULL) 1704 return (pathname); 1705 pathname = search_library_path(name, gethints(nodeflib), 1706 refobj_path, fdp); 1707 if (pathname != NULL) 1708 return (pathname); 1709 if (objgiven && !nodeflib) { 1710 pathname = search_library_path(name, 1711 ld_standard_library_path, refobj_path, fdp); 1712 if (pathname != NULL) 1713 return (pathname); 1714 } 1715 } 1716 1717 if (objgiven && refobj->path != NULL) { 1718 _rtld_error("Shared object \"%s\" not found, " 1719 "required by \"%s\"", name, basename(refobj->path)); 1720 } else { 1721 _rtld_error("Shared object \"%s\" not found", name); 1722 } 1723 return (NULL); 1724 } 1725 1726 /* 1727 * Given a symbol number in a referencing object, find the corresponding 1728 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1729 * no definition was found. Returns a pointer to the Obj_Entry of the 1730 * defining object via the reference parameter DEFOBJ_OUT. 1731 */ 1732 const Elf_Sym * 1733 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1734 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1735 RtldLockState *lockstate) 1736 { 1737 const Elf_Sym *ref; 1738 const Elf_Sym *def; 1739 const Obj_Entry *defobj; 1740 const Ver_Entry *ve; 1741 SymLook req; 1742 const char *name; 1743 int res; 1744 1745 /* 1746 * If we have already found this symbol, get the information from 1747 * the cache. 1748 */ 1749 if (symnum >= refobj->dynsymcount) 1750 return NULL; /* Bad object */ 1751 if (cache != NULL && cache[symnum].sym != NULL) { 1752 *defobj_out = cache[symnum].obj; 1753 return cache[symnum].sym; 1754 } 1755 1756 ref = refobj->symtab + symnum; 1757 name = refobj->strtab + ref->st_name; 1758 def = NULL; 1759 defobj = NULL; 1760 ve = NULL; 1761 1762 /* 1763 * We don't have to do a full scale lookup if the symbol is local. 1764 * We know it will bind to the instance in this load module; to 1765 * which we already have a pointer (ie ref). By not doing a lookup, 1766 * we not only improve performance, but it also avoids unresolvable 1767 * symbols when local symbols are not in the hash table. This has 1768 * been seen with the ia64 toolchain. 1769 */ 1770 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1771 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1772 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1773 symnum); 1774 } 1775 symlook_init(&req, name); 1776 req.flags = flags; 1777 ve = req.ventry = fetch_ventry(refobj, symnum); 1778 req.lockstate = lockstate; 1779 res = symlook_default(&req, refobj); 1780 if (res == 0) { 1781 def = req.sym_out; 1782 defobj = req.defobj_out; 1783 } 1784 } else { 1785 def = ref; 1786 defobj = refobj; 1787 } 1788 1789 /* 1790 * If we found no definition and the reference is weak, treat the 1791 * symbol as having the value zero. 1792 */ 1793 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1794 def = &sym_zero; 1795 defobj = obj_main; 1796 } 1797 1798 if (def != NULL) { 1799 *defobj_out = defobj; 1800 /* Record the information in the cache to avoid subsequent lookups. */ 1801 if (cache != NULL) { 1802 cache[symnum].sym = def; 1803 cache[symnum].obj = defobj; 1804 } 1805 } else { 1806 if (refobj != &obj_rtld) 1807 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1808 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1809 } 1810 return def; 1811 } 1812 1813 /* 1814 * Return the search path from the ldconfig hints file, reading it if 1815 * necessary. If nostdlib is true, then the default search paths are 1816 * not added to result. 1817 * 1818 * Returns NULL if there are problems with the hints file, 1819 * or if the search path there is empty. 1820 */ 1821 static const char * 1822 gethints(bool nostdlib) 1823 { 1824 static char *filtered_path; 1825 static const char *hints; 1826 static struct elfhints_hdr hdr; 1827 struct fill_search_info_args sargs, hargs; 1828 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1829 struct dl_serpath *SLPpath, *hintpath; 1830 char *p; 1831 struct stat hint_stat; 1832 unsigned int SLPndx, hintndx, fndx, fcount; 1833 int fd; 1834 size_t flen; 1835 uint32_t dl; 1836 bool skip; 1837 1838 /* First call, read the hints file */ 1839 if (hints == NULL) { 1840 /* Keep from trying again in case the hints file is bad. */ 1841 hints = ""; 1842 1843 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1844 return (NULL); 1845 1846 /* 1847 * Check of hdr.dirlistlen value against type limit 1848 * intends to pacify static analyzers. Further 1849 * paranoia leads to checks that dirlist is fully 1850 * contained in the file range. 1851 */ 1852 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1853 hdr.magic != ELFHINTS_MAGIC || 1854 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1855 fstat(fd, &hint_stat) == -1) { 1856 cleanup1: 1857 close(fd); 1858 hdr.dirlistlen = 0; 1859 return (NULL); 1860 } 1861 dl = hdr.strtab; 1862 if (dl + hdr.dirlist < dl) 1863 goto cleanup1; 1864 dl += hdr.dirlist; 1865 if (dl + hdr.dirlistlen < dl) 1866 goto cleanup1; 1867 dl += hdr.dirlistlen; 1868 if (dl > hint_stat.st_size) 1869 goto cleanup1; 1870 p = xmalloc(hdr.dirlistlen + 1); 1871 if (pread(fd, p, hdr.dirlistlen + 1, 1872 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1873 p[hdr.dirlistlen] != '\0') { 1874 free(p); 1875 goto cleanup1; 1876 } 1877 hints = p; 1878 close(fd); 1879 } 1880 1881 /* 1882 * If caller agreed to receive list which includes the default 1883 * paths, we are done. Otherwise, if we still did not 1884 * calculated filtered result, do it now. 1885 */ 1886 if (!nostdlib) 1887 return (hints[0] != '\0' ? hints : NULL); 1888 if (filtered_path != NULL) 1889 goto filt_ret; 1890 1891 /* 1892 * Obtain the list of all configured search paths, and the 1893 * list of the default paths. 1894 * 1895 * First estimate the size of the results. 1896 */ 1897 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1898 smeta.dls_cnt = 0; 1899 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1900 hmeta.dls_cnt = 0; 1901 1902 sargs.request = RTLD_DI_SERINFOSIZE; 1903 sargs.serinfo = &smeta; 1904 hargs.request = RTLD_DI_SERINFOSIZE; 1905 hargs.serinfo = &hmeta; 1906 1907 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1908 &sargs); 1909 path_enumerate(hints, fill_search_info, NULL, &hargs); 1910 1911 SLPinfo = xmalloc(smeta.dls_size); 1912 hintinfo = xmalloc(hmeta.dls_size); 1913 1914 /* 1915 * Next fetch both sets of paths. 1916 */ 1917 sargs.request = RTLD_DI_SERINFO; 1918 sargs.serinfo = SLPinfo; 1919 sargs.serpath = &SLPinfo->dls_serpath[0]; 1920 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1921 1922 hargs.request = RTLD_DI_SERINFO; 1923 hargs.serinfo = hintinfo; 1924 hargs.serpath = &hintinfo->dls_serpath[0]; 1925 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1926 1927 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1928 &sargs); 1929 path_enumerate(hints, fill_search_info, NULL, &hargs); 1930 1931 /* 1932 * Now calculate the difference between two sets, by excluding 1933 * standard paths from the full set. 1934 */ 1935 fndx = 0; 1936 fcount = 0; 1937 filtered_path = xmalloc(hdr.dirlistlen + 1); 1938 hintpath = &hintinfo->dls_serpath[0]; 1939 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1940 skip = false; 1941 SLPpath = &SLPinfo->dls_serpath[0]; 1942 /* 1943 * Check each standard path against current. 1944 */ 1945 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1946 /* matched, skip the path */ 1947 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1948 skip = true; 1949 break; 1950 } 1951 } 1952 if (skip) 1953 continue; 1954 /* 1955 * Not matched against any standard path, add the path 1956 * to result. Separate consequtive paths with ':'. 1957 */ 1958 if (fcount > 0) { 1959 filtered_path[fndx] = ':'; 1960 fndx++; 1961 } 1962 fcount++; 1963 flen = strlen(hintpath->dls_name); 1964 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1965 fndx += flen; 1966 } 1967 filtered_path[fndx] = '\0'; 1968 1969 free(SLPinfo); 1970 free(hintinfo); 1971 1972 filt_ret: 1973 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1974 } 1975 1976 static void 1977 init_dag(Obj_Entry *root) 1978 { 1979 const Needed_Entry *needed; 1980 const Objlist_Entry *elm; 1981 DoneList donelist; 1982 1983 if (root->dag_inited) 1984 return; 1985 donelist_init(&donelist); 1986 1987 /* Root object belongs to own DAG. */ 1988 objlist_push_tail(&root->dldags, root); 1989 objlist_push_tail(&root->dagmembers, root); 1990 donelist_check(&donelist, root); 1991 1992 /* 1993 * Add dependencies of root object to DAG in breadth order 1994 * by exploiting the fact that each new object get added 1995 * to the tail of the dagmembers list. 1996 */ 1997 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1998 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1999 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2000 continue; 2001 objlist_push_tail(&needed->obj->dldags, root); 2002 objlist_push_tail(&root->dagmembers, needed->obj); 2003 } 2004 } 2005 root->dag_inited = true; 2006 } 2007 2008 static void 2009 init_marker(Obj_Entry *marker) 2010 { 2011 2012 bzero(marker, sizeof(*marker)); 2013 marker->marker = true; 2014 } 2015 2016 Obj_Entry * 2017 globallist_curr(const Obj_Entry *obj) 2018 { 2019 2020 for (;;) { 2021 if (obj == NULL) 2022 return (NULL); 2023 if (!obj->marker) 2024 return (__DECONST(Obj_Entry *, obj)); 2025 obj = TAILQ_PREV(obj, obj_entry_q, next); 2026 } 2027 } 2028 2029 Obj_Entry * 2030 globallist_next(const Obj_Entry *obj) 2031 { 2032 2033 for (;;) { 2034 obj = TAILQ_NEXT(obj, next); 2035 if (obj == NULL) 2036 return (NULL); 2037 if (!obj->marker) 2038 return (__DECONST(Obj_Entry *, obj)); 2039 } 2040 } 2041 2042 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2043 static void 2044 hold_object(Obj_Entry *obj) 2045 { 2046 2047 obj->holdcount++; 2048 } 2049 2050 static void 2051 unhold_object(Obj_Entry *obj) 2052 { 2053 2054 assert(obj->holdcount > 0); 2055 if (--obj->holdcount == 0 && obj->unholdfree) 2056 release_object(obj); 2057 } 2058 2059 static void 2060 process_z(Obj_Entry *root) 2061 { 2062 const Objlist_Entry *elm; 2063 Obj_Entry *obj; 2064 2065 /* 2066 * Walk over object DAG and process every dependent object 2067 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2068 * to grow their own DAG. 2069 * 2070 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2071 * symlook_global() to work. 2072 * 2073 * For DF_1_NODELETE, the DAG should have its reference upped. 2074 */ 2075 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2076 obj = elm->obj; 2077 if (obj == NULL) 2078 continue; 2079 if (obj->z_nodelete && !obj->ref_nodel) { 2080 dbg("obj %s -z nodelete", obj->path); 2081 init_dag(obj); 2082 ref_dag(obj); 2083 obj->ref_nodel = true; 2084 } 2085 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2086 dbg("obj %s -z global", obj->path); 2087 objlist_push_tail(&list_global, obj); 2088 init_dag(obj); 2089 } 2090 } 2091 } 2092 /* 2093 * Initialize the dynamic linker. The argument is the address at which 2094 * the dynamic linker has been mapped into memory. The primary task of 2095 * this function is to relocate the dynamic linker. 2096 */ 2097 static void 2098 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2099 { 2100 Obj_Entry objtmp; /* Temporary rtld object */ 2101 const Elf_Ehdr *ehdr; 2102 const Elf_Dyn *dyn_rpath; 2103 const Elf_Dyn *dyn_soname; 2104 const Elf_Dyn *dyn_runpath; 2105 2106 #ifdef RTLD_INIT_PAGESIZES_EARLY 2107 /* The page size is required by the dynamic memory allocator. */ 2108 init_pagesizes(aux_info); 2109 #endif 2110 2111 /* 2112 * Conjure up an Obj_Entry structure for the dynamic linker. 2113 * 2114 * The "path" member can't be initialized yet because string constants 2115 * cannot yet be accessed. Below we will set it correctly. 2116 */ 2117 memset(&objtmp, 0, sizeof(objtmp)); 2118 objtmp.path = NULL; 2119 objtmp.rtld = true; 2120 objtmp.mapbase = mapbase; 2121 #ifdef PIC 2122 objtmp.relocbase = mapbase; 2123 #endif 2124 2125 objtmp.dynamic = rtld_dynamic(&objtmp); 2126 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2127 assert(objtmp.needed == NULL); 2128 #if !defined(__mips__) 2129 /* MIPS has a bogus DT_TEXTREL. */ 2130 assert(!objtmp.textrel); 2131 #endif 2132 /* 2133 * Temporarily put the dynamic linker entry into the object list, so 2134 * that symbols can be found. 2135 */ 2136 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2137 2138 ehdr = (Elf_Ehdr *)mapbase; 2139 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2140 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2141 2142 /* Initialize the object list. */ 2143 TAILQ_INIT(&obj_list); 2144 2145 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2146 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2147 2148 #ifndef RTLD_INIT_PAGESIZES_EARLY 2149 /* The page size is required by the dynamic memory allocator. */ 2150 init_pagesizes(aux_info); 2151 #endif 2152 2153 if (aux_info[AT_OSRELDATE] != NULL) 2154 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2155 2156 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2157 2158 /* Replace the path with a dynamically allocated copy. */ 2159 obj_rtld.path = xstrdup(ld_path_rtld); 2160 2161 r_debug.r_brk = r_debug_state; 2162 r_debug.r_state = RT_CONSISTENT; 2163 } 2164 2165 /* 2166 * Retrieve the array of supported page sizes. The kernel provides the page 2167 * sizes in increasing order. 2168 */ 2169 static void 2170 init_pagesizes(Elf_Auxinfo **aux_info) 2171 { 2172 static size_t psa[MAXPAGESIZES]; 2173 int mib[2]; 2174 size_t len, size; 2175 2176 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2177 NULL) { 2178 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2179 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2180 } else { 2181 len = 2; 2182 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2183 size = sizeof(psa); 2184 else { 2185 /* As a fallback, retrieve the base page size. */ 2186 size = sizeof(psa[0]); 2187 if (aux_info[AT_PAGESZ] != NULL) { 2188 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2189 goto psa_filled; 2190 } else { 2191 mib[0] = CTL_HW; 2192 mib[1] = HW_PAGESIZE; 2193 len = 2; 2194 } 2195 } 2196 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2197 _rtld_error("sysctl for hw.pagesize(s) failed"); 2198 rtld_die(); 2199 } 2200 psa_filled: 2201 pagesizes = psa; 2202 } 2203 npagesizes = size / sizeof(pagesizes[0]); 2204 /* Discard any invalid entries at the end of the array. */ 2205 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2206 npagesizes--; 2207 } 2208 2209 /* 2210 * Add the init functions from a needed object list (and its recursive 2211 * needed objects) to "list". This is not used directly; it is a helper 2212 * function for initlist_add_objects(). The write lock must be held 2213 * when this function is called. 2214 */ 2215 static void 2216 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2217 { 2218 /* Recursively process the successor needed objects. */ 2219 if (needed->next != NULL) 2220 initlist_add_neededs(needed->next, list); 2221 2222 /* Process the current needed object. */ 2223 if (needed->obj != NULL) 2224 initlist_add_objects(needed->obj, needed->obj, list); 2225 } 2226 2227 /* 2228 * Scan all of the DAGs rooted in the range of objects from "obj" to 2229 * "tail" and add their init functions to "list". This recurses over 2230 * the DAGs and ensure the proper init ordering such that each object's 2231 * needed libraries are initialized before the object itself. At the 2232 * same time, this function adds the objects to the global finalization 2233 * list "list_fini" in the opposite order. The write lock must be 2234 * held when this function is called. 2235 */ 2236 static void 2237 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2238 { 2239 Obj_Entry *nobj; 2240 2241 if (obj->init_scanned || obj->init_done) 2242 return; 2243 obj->init_scanned = true; 2244 2245 /* Recursively process the successor objects. */ 2246 nobj = globallist_next(obj); 2247 if (nobj != NULL && obj != tail) 2248 initlist_add_objects(nobj, tail, list); 2249 2250 /* Recursively process the needed objects. */ 2251 if (obj->needed != NULL) 2252 initlist_add_neededs(obj->needed, list); 2253 if (obj->needed_filtees != NULL) 2254 initlist_add_neededs(obj->needed_filtees, list); 2255 if (obj->needed_aux_filtees != NULL) 2256 initlist_add_neededs(obj->needed_aux_filtees, list); 2257 2258 /* Add the object to the init list. */ 2259 objlist_push_tail(list, obj); 2260 2261 /* Add the object to the global fini list in the reverse order. */ 2262 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2263 && !obj->on_fini_list) { 2264 objlist_push_head(&list_fini, obj); 2265 obj->on_fini_list = true; 2266 } 2267 } 2268 2269 #ifndef FPTR_TARGET 2270 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2271 #endif 2272 2273 static void 2274 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2275 { 2276 Needed_Entry *needed, *needed1; 2277 2278 for (needed = n; needed != NULL; needed = needed->next) { 2279 if (needed->obj != NULL) { 2280 dlclose_locked(needed->obj, lockstate); 2281 needed->obj = NULL; 2282 } 2283 } 2284 for (needed = n; needed != NULL; needed = needed1) { 2285 needed1 = needed->next; 2286 free(needed); 2287 } 2288 } 2289 2290 static void 2291 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2292 { 2293 2294 free_needed_filtees(obj->needed_filtees, lockstate); 2295 obj->needed_filtees = NULL; 2296 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2297 obj->needed_aux_filtees = NULL; 2298 obj->filtees_loaded = false; 2299 } 2300 2301 static void 2302 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2303 RtldLockState *lockstate) 2304 { 2305 2306 for (; needed != NULL; needed = needed->next) { 2307 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2308 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2309 RTLD_LOCAL, lockstate); 2310 } 2311 } 2312 2313 static void 2314 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2315 { 2316 2317 lock_restart_for_upgrade(lockstate); 2318 if (!obj->filtees_loaded) { 2319 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2320 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2321 obj->filtees_loaded = true; 2322 } 2323 } 2324 2325 static int 2326 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2327 { 2328 Obj_Entry *obj1; 2329 2330 for (; needed != NULL; needed = needed->next) { 2331 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2332 flags & ~RTLD_LO_NOLOAD); 2333 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2334 return (-1); 2335 } 2336 return (0); 2337 } 2338 2339 /* 2340 * Given a shared object, traverse its list of needed objects, and load 2341 * each of them. Returns 0 on success. Generates an error message and 2342 * returns -1 on failure. 2343 */ 2344 static int 2345 load_needed_objects(Obj_Entry *first, int flags) 2346 { 2347 Obj_Entry *obj; 2348 2349 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2350 if (obj->marker) 2351 continue; 2352 if (process_needed(obj, obj->needed, flags) == -1) 2353 return (-1); 2354 } 2355 return (0); 2356 } 2357 2358 static int 2359 load_preload_objects(void) 2360 { 2361 char *p = ld_preload; 2362 Obj_Entry *obj; 2363 static const char delim[] = " \t:;"; 2364 2365 if (p == NULL) 2366 return 0; 2367 2368 p += strspn(p, delim); 2369 while (*p != '\0') { 2370 size_t len = strcspn(p, delim); 2371 char savech; 2372 2373 savech = p[len]; 2374 p[len] = '\0'; 2375 obj = load_object(p, -1, NULL, 0); 2376 if (obj == NULL) 2377 return -1; /* XXX - cleanup */ 2378 obj->z_interpose = true; 2379 p[len] = savech; 2380 p += len; 2381 p += strspn(p, delim); 2382 } 2383 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2384 return 0; 2385 } 2386 2387 static const char * 2388 printable_path(const char *path) 2389 { 2390 2391 return (path == NULL ? "<unknown>" : path); 2392 } 2393 2394 /* 2395 * Load a shared object into memory, if it is not already loaded. The 2396 * object may be specified by name or by user-supplied file descriptor 2397 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2398 * duplicate is. 2399 * 2400 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2401 * on failure. 2402 */ 2403 static Obj_Entry * 2404 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2405 { 2406 Obj_Entry *obj; 2407 int fd; 2408 struct stat sb; 2409 char *path; 2410 2411 fd = -1; 2412 if (name != NULL) { 2413 TAILQ_FOREACH(obj, &obj_list, next) { 2414 if (obj->marker || obj->doomed) 2415 continue; 2416 if (object_match_name(obj, name)) 2417 return (obj); 2418 } 2419 2420 path = find_library(name, refobj, &fd); 2421 if (path == NULL) 2422 return (NULL); 2423 } else 2424 path = NULL; 2425 2426 if (fd >= 0) { 2427 /* 2428 * search_library_pathfds() opens a fresh file descriptor for the 2429 * library, so there is no need to dup(). 2430 */ 2431 } else if (fd_u == -1) { 2432 /* 2433 * If we didn't find a match by pathname, or the name is not 2434 * supplied, open the file and check again by device and inode. 2435 * This avoids false mismatches caused by multiple links or ".." 2436 * in pathnames. 2437 * 2438 * To avoid a race, we open the file and use fstat() rather than 2439 * using stat(). 2440 */ 2441 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2442 _rtld_error("Cannot open \"%s\"", path); 2443 free(path); 2444 return (NULL); 2445 } 2446 } else { 2447 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2448 if (fd == -1) { 2449 _rtld_error("Cannot dup fd"); 2450 free(path); 2451 return (NULL); 2452 } 2453 } 2454 if (fstat(fd, &sb) == -1) { 2455 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2456 close(fd); 2457 free(path); 2458 return NULL; 2459 } 2460 TAILQ_FOREACH(obj, &obj_list, next) { 2461 if (obj->marker || obj->doomed) 2462 continue; 2463 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2464 break; 2465 } 2466 if (obj != NULL && name != NULL) { 2467 object_add_name(obj, name); 2468 free(path); 2469 close(fd); 2470 return obj; 2471 } 2472 if (flags & RTLD_LO_NOLOAD) { 2473 free(path); 2474 close(fd); 2475 return (NULL); 2476 } 2477 2478 /* First use of this object, so we must map it in */ 2479 obj = do_load_object(fd, name, path, &sb, flags); 2480 if (obj == NULL) 2481 free(path); 2482 close(fd); 2483 2484 return obj; 2485 } 2486 2487 static Obj_Entry * 2488 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2489 int flags) 2490 { 2491 Obj_Entry *obj; 2492 struct statfs fs; 2493 2494 /* 2495 * but first, make sure that environment variables haven't been 2496 * used to circumvent the noexec flag on a filesystem. 2497 */ 2498 if (dangerous_ld_env) { 2499 if (fstatfs(fd, &fs) != 0) { 2500 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2501 return NULL; 2502 } 2503 if (fs.f_flags & MNT_NOEXEC) { 2504 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2505 return NULL; 2506 } 2507 } 2508 dbg("loading \"%s\"", printable_path(path)); 2509 obj = map_object(fd, printable_path(path), sbp); 2510 if (obj == NULL) 2511 return NULL; 2512 2513 /* 2514 * If DT_SONAME is present in the object, digest_dynamic2 already 2515 * added it to the object names. 2516 */ 2517 if (name != NULL) 2518 object_add_name(obj, name); 2519 obj->path = path; 2520 digest_dynamic(obj, 0); 2521 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2522 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2523 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2524 RTLD_LO_DLOPEN) { 2525 dbg("refusing to load non-loadable \"%s\"", obj->path); 2526 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2527 munmap(obj->mapbase, obj->mapsize); 2528 obj_free(obj); 2529 return (NULL); 2530 } 2531 2532 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2533 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2534 obj_count++; 2535 obj_loads++; 2536 linkmap_add(obj); /* for GDB & dlinfo() */ 2537 max_stack_flags |= obj->stack_flags; 2538 2539 dbg(" %p .. %p: %s", obj->mapbase, 2540 obj->mapbase + obj->mapsize - 1, obj->path); 2541 if (obj->textrel) 2542 dbg(" WARNING: %s has impure text", obj->path); 2543 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2544 obj->path); 2545 2546 return obj; 2547 } 2548 2549 static Obj_Entry * 2550 obj_from_addr(const void *addr) 2551 { 2552 Obj_Entry *obj; 2553 2554 TAILQ_FOREACH(obj, &obj_list, next) { 2555 if (obj->marker) 2556 continue; 2557 if (addr < (void *) obj->mapbase) 2558 continue; 2559 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2560 return obj; 2561 } 2562 return NULL; 2563 } 2564 2565 static void 2566 preinit_main(void) 2567 { 2568 Elf_Addr *preinit_addr; 2569 int index; 2570 2571 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2572 if (preinit_addr == NULL) 2573 return; 2574 2575 for (index = 0; index < obj_main->preinit_array_num; index++) { 2576 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2577 dbg("calling preinit function for %s at %p", obj_main->path, 2578 (void *)preinit_addr[index]); 2579 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2580 0, 0, obj_main->path); 2581 call_init_pointer(obj_main, preinit_addr[index]); 2582 } 2583 } 2584 } 2585 2586 /* 2587 * Call the finalization functions for each of the objects in "list" 2588 * belonging to the DAG of "root" and referenced once. If NULL "root" 2589 * is specified, every finalization function will be called regardless 2590 * of the reference count and the list elements won't be freed. All of 2591 * the objects are expected to have non-NULL fini functions. 2592 */ 2593 static void 2594 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2595 { 2596 Objlist_Entry *elm; 2597 char *saved_msg; 2598 Elf_Addr *fini_addr; 2599 int index; 2600 2601 assert(root == NULL || root->refcount == 1); 2602 2603 if (root != NULL) 2604 root->doomed = true; 2605 2606 /* 2607 * Preserve the current error message since a fini function might 2608 * call into the dynamic linker and overwrite it. 2609 */ 2610 saved_msg = errmsg_save(); 2611 do { 2612 STAILQ_FOREACH(elm, list, link) { 2613 if (root != NULL && (elm->obj->refcount != 1 || 2614 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2615 continue; 2616 /* Remove object from fini list to prevent recursive invocation. */ 2617 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2618 /* Ensure that new references cannot be acquired. */ 2619 elm->obj->doomed = true; 2620 2621 hold_object(elm->obj); 2622 lock_release(rtld_bind_lock, lockstate); 2623 /* 2624 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2625 * When this happens, DT_FINI_ARRAY is processed first. 2626 */ 2627 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2628 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2629 for (index = elm->obj->fini_array_num - 1; index >= 0; 2630 index--) { 2631 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2632 dbg("calling fini function for %s at %p", 2633 elm->obj->path, (void *)fini_addr[index]); 2634 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2635 (void *)fini_addr[index], 0, 0, elm->obj->path); 2636 call_initfini_pointer(elm->obj, fini_addr[index]); 2637 } 2638 } 2639 } 2640 if (elm->obj->fini != (Elf_Addr)NULL) { 2641 dbg("calling fini function for %s at %p", elm->obj->path, 2642 (void *)elm->obj->fini); 2643 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2644 0, 0, elm->obj->path); 2645 call_initfini_pointer(elm->obj, elm->obj->fini); 2646 } 2647 wlock_acquire(rtld_bind_lock, lockstate); 2648 unhold_object(elm->obj); 2649 /* No need to free anything if process is going down. */ 2650 if (root != NULL) 2651 free(elm); 2652 /* 2653 * We must restart the list traversal after every fini call 2654 * because a dlclose() call from the fini function or from 2655 * another thread might have modified the reference counts. 2656 */ 2657 break; 2658 } 2659 } while (elm != NULL); 2660 errmsg_restore(saved_msg); 2661 } 2662 2663 /* 2664 * Call the initialization functions for each of the objects in 2665 * "list". All of the objects are expected to have non-NULL init 2666 * functions. 2667 */ 2668 static void 2669 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2670 { 2671 Objlist_Entry *elm; 2672 Obj_Entry *obj; 2673 char *saved_msg; 2674 Elf_Addr *init_addr; 2675 void (*reg)(void (*)(void)); 2676 int index; 2677 2678 /* 2679 * Clean init_scanned flag so that objects can be rechecked and 2680 * possibly initialized earlier if any of vectors called below 2681 * cause the change by using dlopen. 2682 */ 2683 TAILQ_FOREACH(obj, &obj_list, next) { 2684 if (obj->marker) 2685 continue; 2686 obj->init_scanned = false; 2687 } 2688 2689 /* 2690 * Preserve the current error message since an init function might 2691 * call into the dynamic linker and overwrite it. 2692 */ 2693 saved_msg = errmsg_save(); 2694 STAILQ_FOREACH(elm, list, link) { 2695 if (elm->obj->init_done) /* Initialized early. */ 2696 continue; 2697 /* 2698 * Race: other thread might try to use this object before current 2699 * one completes the initialization. Not much can be done here 2700 * without better locking. 2701 */ 2702 elm->obj->init_done = true; 2703 hold_object(elm->obj); 2704 reg = NULL; 2705 if (elm->obj == obj_main && obj_main->crt_no_init) { 2706 reg = (void (*)(void (*)(void)))get_program_var_addr( 2707 "__libc_atexit", lockstate); 2708 } 2709 lock_release(rtld_bind_lock, lockstate); 2710 if (reg != NULL) { 2711 reg(rtld_exit); 2712 rtld_exit_ptr = rtld_nop_exit; 2713 } 2714 2715 /* 2716 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2717 * When this happens, DT_INIT is processed first. 2718 */ 2719 if (elm->obj->init != (Elf_Addr)NULL) { 2720 dbg("calling init function for %s at %p", elm->obj->path, 2721 (void *)elm->obj->init); 2722 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2723 0, 0, elm->obj->path); 2724 call_initfini_pointer(elm->obj, elm->obj->init); 2725 } 2726 init_addr = (Elf_Addr *)elm->obj->init_array; 2727 if (init_addr != NULL) { 2728 for (index = 0; index < elm->obj->init_array_num; index++) { 2729 if (init_addr[index] != 0 && init_addr[index] != 1) { 2730 dbg("calling init function for %s at %p", elm->obj->path, 2731 (void *)init_addr[index]); 2732 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2733 (void *)init_addr[index], 0, 0, elm->obj->path); 2734 call_init_pointer(elm->obj, init_addr[index]); 2735 } 2736 } 2737 } 2738 wlock_acquire(rtld_bind_lock, lockstate); 2739 unhold_object(elm->obj); 2740 } 2741 errmsg_restore(saved_msg); 2742 } 2743 2744 static void 2745 objlist_clear(Objlist *list) 2746 { 2747 Objlist_Entry *elm; 2748 2749 while (!STAILQ_EMPTY(list)) { 2750 elm = STAILQ_FIRST(list); 2751 STAILQ_REMOVE_HEAD(list, link); 2752 free(elm); 2753 } 2754 } 2755 2756 static Objlist_Entry * 2757 objlist_find(Objlist *list, const Obj_Entry *obj) 2758 { 2759 Objlist_Entry *elm; 2760 2761 STAILQ_FOREACH(elm, list, link) 2762 if (elm->obj == obj) 2763 return elm; 2764 return NULL; 2765 } 2766 2767 static void 2768 objlist_init(Objlist *list) 2769 { 2770 STAILQ_INIT(list); 2771 } 2772 2773 static void 2774 objlist_push_head(Objlist *list, Obj_Entry *obj) 2775 { 2776 Objlist_Entry *elm; 2777 2778 elm = NEW(Objlist_Entry); 2779 elm->obj = obj; 2780 STAILQ_INSERT_HEAD(list, elm, link); 2781 } 2782 2783 static void 2784 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2785 { 2786 Objlist_Entry *elm; 2787 2788 elm = NEW(Objlist_Entry); 2789 elm->obj = obj; 2790 STAILQ_INSERT_TAIL(list, elm, link); 2791 } 2792 2793 static void 2794 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2795 { 2796 Objlist_Entry *elm, *listelm; 2797 2798 STAILQ_FOREACH(listelm, list, link) { 2799 if (listelm->obj == listobj) 2800 break; 2801 } 2802 elm = NEW(Objlist_Entry); 2803 elm->obj = obj; 2804 if (listelm != NULL) 2805 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2806 else 2807 STAILQ_INSERT_TAIL(list, elm, link); 2808 } 2809 2810 static void 2811 objlist_remove(Objlist *list, Obj_Entry *obj) 2812 { 2813 Objlist_Entry *elm; 2814 2815 if ((elm = objlist_find(list, obj)) != NULL) { 2816 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2817 free(elm); 2818 } 2819 } 2820 2821 /* 2822 * Relocate dag rooted in the specified object. 2823 * Returns 0 on success, or -1 on failure. 2824 */ 2825 2826 static int 2827 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2828 int flags, RtldLockState *lockstate) 2829 { 2830 Objlist_Entry *elm; 2831 int error; 2832 2833 error = 0; 2834 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2835 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2836 lockstate); 2837 if (error == -1) 2838 break; 2839 } 2840 return (error); 2841 } 2842 2843 /* 2844 * Prepare for, or clean after, relocating an object marked with 2845 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2846 * segments are remapped read-write. After relocations are done, the 2847 * segment's permissions are returned back to the modes specified in 2848 * the phdrs. If any relocation happened, or always for wired 2849 * program, COW is triggered. 2850 */ 2851 static int 2852 reloc_textrel_prot(Obj_Entry *obj, bool before) 2853 { 2854 const Elf_Phdr *ph; 2855 void *base; 2856 size_t l, sz; 2857 int prot; 2858 2859 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2860 l--, ph++) { 2861 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2862 continue; 2863 base = obj->relocbase + trunc_page(ph->p_vaddr); 2864 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2865 trunc_page(ph->p_vaddr); 2866 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2867 if (mprotect(base, sz, prot) == -1) { 2868 _rtld_error("%s: Cannot write-%sable text segment: %s", 2869 obj->path, before ? "en" : "dis", 2870 rtld_strerror(errno)); 2871 return (-1); 2872 } 2873 } 2874 return (0); 2875 } 2876 2877 /* 2878 * Relocate single object. 2879 * Returns 0 on success, or -1 on failure. 2880 */ 2881 static int 2882 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2883 int flags, RtldLockState *lockstate) 2884 { 2885 2886 if (obj->relocated) 2887 return (0); 2888 obj->relocated = true; 2889 if (obj != rtldobj) 2890 dbg("relocating \"%s\"", obj->path); 2891 2892 if (obj->symtab == NULL || obj->strtab == NULL || 2893 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2894 _rtld_error("%s: Shared object has no run-time symbol table", 2895 obj->path); 2896 return (-1); 2897 } 2898 2899 /* There are relocations to the write-protected text segment. */ 2900 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2901 return (-1); 2902 2903 /* Process the non-PLT non-IFUNC relocations. */ 2904 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2905 return (-1); 2906 2907 /* Re-protected the text segment. */ 2908 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2909 return (-1); 2910 2911 /* Set the special PLT or GOT entries. */ 2912 init_pltgot(obj); 2913 2914 /* Process the PLT relocations. */ 2915 if (reloc_plt(obj, flags, lockstate) == -1) 2916 return (-1); 2917 /* Relocate the jump slots if we are doing immediate binding. */ 2918 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2919 lockstate) == -1) 2920 return (-1); 2921 2922 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2923 return (-1); 2924 2925 /* 2926 * Set up the magic number and version in the Obj_Entry. These 2927 * were checked in the crt1.o from the original ElfKit, so we 2928 * set them for backward compatibility. 2929 */ 2930 obj->magic = RTLD_MAGIC; 2931 obj->version = RTLD_VERSION; 2932 2933 return (0); 2934 } 2935 2936 /* 2937 * Relocate newly-loaded shared objects. The argument is a pointer to 2938 * the Obj_Entry for the first such object. All objects from the first 2939 * to the end of the list of objects are relocated. Returns 0 on success, 2940 * or -1 on failure. 2941 */ 2942 static int 2943 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2944 int flags, RtldLockState *lockstate) 2945 { 2946 Obj_Entry *obj; 2947 int error; 2948 2949 for (error = 0, obj = first; obj != NULL; 2950 obj = TAILQ_NEXT(obj, next)) { 2951 if (obj->marker) 2952 continue; 2953 error = relocate_object(obj, bind_now, rtldobj, flags, 2954 lockstate); 2955 if (error == -1) 2956 break; 2957 } 2958 return (error); 2959 } 2960 2961 /* 2962 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2963 * referencing STT_GNU_IFUNC symbols is postponed till the other 2964 * relocations are done. The indirect functions specified as 2965 * ifunc are allowed to call other symbols, so we need to have 2966 * objects relocated before asking for resolution from indirects. 2967 * 2968 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2969 * instead of the usual lazy handling of PLT slots. It is 2970 * consistent with how GNU does it. 2971 */ 2972 static int 2973 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2974 RtldLockState *lockstate) 2975 { 2976 2977 if (obj->ifuncs_resolved) 2978 return (0); 2979 obj->ifuncs_resolved = true; 2980 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 2981 return (0); 2982 if (obj_disable_relro(obj) == -1 || 2983 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 2984 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2985 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 2986 obj_enforce_relro(obj) == -1) 2987 return (-1); 2988 return (0); 2989 } 2990 2991 static int 2992 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2993 RtldLockState *lockstate) 2994 { 2995 Objlist_Entry *elm; 2996 Obj_Entry *obj; 2997 2998 STAILQ_FOREACH(elm, list, link) { 2999 obj = elm->obj; 3000 if (obj->marker) 3001 continue; 3002 if (resolve_object_ifunc(obj, bind_now, flags, 3003 lockstate) == -1) 3004 return (-1); 3005 } 3006 return (0); 3007 } 3008 3009 /* 3010 * Cleanup procedure. It will be called (by the atexit mechanism) just 3011 * before the process exits. 3012 */ 3013 static void 3014 rtld_exit(void) 3015 { 3016 RtldLockState lockstate; 3017 3018 wlock_acquire(rtld_bind_lock, &lockstate); 3019 dbg("rtld_exit()"); 3020 objlist_call_fini(&list_fini, NULL, &lockstate); 3021 /* No need to remove the items from the list, since we are exiting. */ 3022 if (!libmap_disable) 3023 lm_fini(); 3024 lock_release(rtld_bind_lock, &lockstate); 3025 } 3026 3027 static void 3028 rtld_nop_exit(void) 3029 { 3030 } 3031 3032 /* 3033 * Iterate over a search path, translate each element, and invoke the 3034 * callback on the result. 3035 */ 3036 static void * 3037 path_enumerate(const char *path, path_enum_proc callback, 3038 const char *refobj_path, void *arg) 3039 { 3040 const char *trans; 3041 if (path == NULL) 3042 return (NULL); 3043 3044 path += strspn(path, ":;"); 3045 while (*path != '\0') { 3046 size_t len; 3047 char *res; 3048 3049 len = strcspn(path, ":;"); 3050 trans = lm_findn(refobj_path, path, len); 3051 if (trans) 3052 res = callback(trans, strlen(trans), arg); 3053 else 3054 res = callback(path, len, arg); 3055 3056 if (res != NULL) 3057 return (res); 3058 3059 path += len; 3060 path += strspn(path, ":;"); 3061 } 3062 3063 return (NULL); 3064 } 3065 3066 struct try_library_args { 3067 const char *name; 3068 size_t namelen; 3069 char *buffer; 3070 size_t buflen; 3071 int fd; 3072 }; 3073 3074 static void * 3075 try_library_path(const char *dir, size_t dirlen, void *param) 3076 { 3077 struct try_library_args *arg; 3078 int fd; 3079 3080 arg = param; 3081 if (*dir == '/' || trust) { 3082 char *pathname; 3083 3084 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3085 return (NULL); 3086 3087 pathname = arg->buffer; 3088 strncpy(pathname, dir, dirlen); 3089 pathname[dirlen] = '/'; 3090 strcpy(pathname + dirlen + 1, arg->name); 3091 3092 dbg(" Trying \"%s\"", pathname); 3093 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3094 if (fd >= 0) { 3095 dbg(" Opened \"%s\", fd %d", pathname, fd); 3096 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3097 strcpy(pathname, arg->buffer); 3098 arg->fd = fd; 3099 return (pathname); 3100 } else { 3101 dbg(" Failed to open \"%s\": %s", 3102 pathname, rtld_strerror(errno)); 3103 } 3104 } 3105 return (NULL); 3106 } 3107 3108 static char * 3109 search_library_path(const char *name, const char *path, 3110 const char *refobj_path, int *fdp) 3111 { 3112 char *p; 3113 struct try_library_args arg; 3114 3115 if (path == NULL) 3116 return NULL; 3117 3118 arg.name = name; 3119 arg.namelen = strlen(name); 3120 arg.buffer = xmalloc(PATH_MAX); 3121 arg.buflen = PATH_MAX; 3122 arg.fd = -1; 3123 3124 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3125 *fdp = arg.fd; 3126 3127 free(arg.buffer); 3128 3129 return (p); 3130 } 3131 3132 3133 /* 3134 * Finds the library with the given name using the directory descriptors 3135 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3136 * 3137 * Returns a freshly-opened close-on-exec file descriptor for the library, 3138 * or -1 if the library cannot be found. 3139 */ 3140 static char * 3141 search_library_pathfds(const char *name, const char *path, int *fdp) 3142 { 3143 char *envcopy, *fdstr, *found, *last_token; 3144 size_t len; 3145 int dirfd, fd; 3146 3147 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3148 3149 /* Don't load from user-specified libdirs into setuid binaries. */ 3150 if (!trust) 3151 return (NULL); 3152 3153 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3154 if (path == NULL) 3155 return (NULL); 3156 3157 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3158 if (name[0] == '/') { 3159 dbg("Absolute path (%s) passed to %s", name, __func__); 3160 return (NULL); 3161 } 3162 3163 /* 3164 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3165 * copy of the path, as strtok_r rewrites separator tokens 3166 * with '\0'. 3167 */ 3168 found = NULL; 3169 envcopy = xstrdup(path); 3170 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3171 fdstr = strtok_r(NULL, ":", &last_token)) { 3172 dirfd = parse_integer(fdstr); 3173 if (dirfd < 0) { 3174 _rtld_error("failed to parse directory FD: '%s'", 3175 fdstr); 3176 break; 3177 } 3178 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3179 if (fd >= 0) { 3180 *fdp = fd; 3181 len = strlen(fdstr) + strlen(name) + 3; 3182 found = xmalloc(len); 3183 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3184 _rtld_error("error generating '%d/%s'", 3185 dirfd, name); 3186 rtld_die(); 3187 } 3188 dbg("open('%s') => %d", found, fd); 3189 break; 3190 } 3191 } 3192 free(envcopy); 3193 3194 return (found); 3195 } 3196 3197 3198 int 3199 dlclose(void *handle) 3200 { 3201 RtldLockState lockstate; 3202 int error; 3203 3204 wlock_acquire(rtld_bind_lock, &lockstate); 3205 error = dlclose_locked(handle, &lockstate); 3206 lock_release(rtld_bind_lock, &lockstate); 3207 return (error); 3208 } 3209 3210 static int 3211 dlclose_locked(void *handle, RtldLockState *lockstate) 3212 { 3213 Obj_Entry *root; 3214 3215 root = dlcheck(handle); 3216 if (root == NULL) 3217 return -1; 3218 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3219 root->path); 3220 3221 /* Unreference the object and its dependencies. */ 3222 root->dl_refcount--; 3223 3224 if (root->refcount == 1) { 3225 /* 3226 * The object will be no longer referenced, so we must unload it. 3227 * First, call the fini functions. 3228 */ 3229 objlist_call_fini(&list_fini, root, lockstate); 3230 3231 unref_dag(root); 3232 3233 /* Finish cleaning up the newly-unreferenced objects. */ 3234 GDB_STATE(RT_DELETE,&root->linkmap); 3235 unload_object(root, lockstate); 3236 GDB_STATE(RT_CONSISTENT,NULL); 3237 } else 3238 unref_dag(root); 3239 3240 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3241 return 0; 3242 } 3243 3244 char * 3245 dlerror(void) 3246 { 3247 char *msg = error_message; 3248 error_message = NULL; 3249 return msg; 3250 } 3251 3252 /* 3253 * This function is deprecated and has no effect. 3254 */ 3255 void 3256 dllockinit(void *context, 3257 void *(*_lock_create)(void *context) __unused, 3258 void (*_rlock_acquire)(void *lock) __unused, 3259 void (*_wlock_acquire)(void *lock) __unused, 3260 void (*_lock_release)(void *lock) __unused, 3261 void (*_lock_destroy)(void *lock) __unused, 3262 void (*context_destroy)(void *context)) 3263 { 3264 static void *cur_context; 3265 static void (*cur_context_destroy)(void *); 3266 3267 /* Just destroy the context from the previous call, if necessary. */ 3268 if (cur_context_destroy != NULL) 3269 cur_context_destroy(cur_context); 3270 cur_context = context; 3271 cur_context_destroy = context_destroy; 3272 } 3273 3274 void * 3275 dlopen(const char *name, int mode) 3276 { 3277 3278 return (rtld_dlopen(name, -1, mode)); 3279 } 3280 3281 void * 3282 fdlopen(int fd, int mode) 3283 { 3284 3285 return (rtld_dlopen(NULL, fd, mode)); 3286 } 3287 3288 static void * 3289 rtld_dlopen(const char *name, int fd, int mode) 3290 { 3291 RtldLockState lockstate; 3292 int lo_flags; 3293 3294 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3295 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3296 if (ld_tracing != NULL) { 3297 rlock_acquire(rtld_bind_lock, &lockstate); 3298 if (sigsetjmp(lockstate.env, 0) != 0) 3299 lock_upgrade(rtld_bind_lock, &lockstate); 3300 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3301 lock_release(rtld_bind_lock, &lockstate); 3302 } 3303 lo_flags = RTLD_LO_DLOPEN; 3304 if (mode & RTLD_NODELETE) 3305 lo_flags |= RTLD_LO_NODELETE; 3306 if (mode & RTLD_NOLOAD) 3307 lo_flags |= RTLD_LO_NOLOAD; 3308 if (ld_tracing != NULL) 3309 lo_flags |= RTLD_LO_TRACE; 3310 3311 return (dlopen_object(name, fd, obj_main, lo_flags, 3312 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3313 } 3314 3315 static void 3316 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3317 { 3318 3319 obj->dl_refcount--; 3320 unref_dag(obj); 3321 if (obj->refcount == 0) 3322 unload_object(obj, lockstate); 3323 } 3324 3325 static Obj_Entry * 3326 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3327 int mode, RtldLockState *lockstate) 3328 { 3329 Obj_Entry *old_obj_tail; 3330 Obj_Entry *obj; 3331 Objlist initlist; 3332 RtldLockState mlockstate; 3333 int result; 3334 3335 objlist_init(&initlist); 3336 3337 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3338 wlock_acquire(rtld_bind_lock, &mlockstate); 3339 lockstate = &mlockstate; 3340 } 3341 GDB_STATE(RT_ADD,NULL); 3342 3343 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3344 obj = NULL; 3345 if (name == NULL && fd == -1) { 3346 obj = obj_main; 3347 obj->refcount++; 3348 } else { 3349 obj = load_object(name, fd, refobj, lo_flags); 3350 } 3351 3352 if (obj) { 3353 obj->dl_refcount++; 3354 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3355 objlist_push_tail(&list_global, obj); 3356 if (globallist_next(old_obj_tail) != NULL) { 3357 /* We loaded something new. */ 3358 assert(globallist_next(old_obj_tail) == obj); 3359 result = 0; 3360 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3361 !allocate_tls_offset(obj)) { 3362 _rtld_error("%s: No space available " 3363 "for static Thread Local Storage", obj->path); 3364 result = -1; 3365 } 3366 if (result != -1) 3367 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3368 RTLD_LO_EARLY)); 3369 init_dag(obj); 3370 ref_dag(obj); 3371 if (result != -1) 3372 result = rtld_verify_versions(&obj->dagmembers); 3373 if (result != -1 && ld_tracing) 3374 goto trace; 3375 if (result == -1 || relocate_object_dag(obj, 3376 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3377 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3378 lockstate) == -1) { 3379 dlopen_cleanup(obj, lockstate); 3380 obj = NULL; 3381 } else if (lo_flags & RTLD_LO_EARLY) { 3382 /* 3383 * Do not call the init functions for early loaded 3384 * filtees. The image is still not initialized enough 3385 * for them to work. 3386 * 3387 * Our object is found by the global object list and 3388 * will be ordered among all init calls done right 3389 * before transferring control to main. 3390 */ 3391 } else { 3392 /* Make list of init functions to call. */ 3393 initlist_add_objects(obj, obj, &initlist); 3394 } 3395 /* 3396 * Process all no_delete or global objects here, given 3397 * them own DAGs to prevent their dependencies from being 3398 * unloaded. This has to be done after we have loaded all 3399 * of the dependencies, so that we do not miss any. 3400 */ 3401 if (obj != NULL) 3402 process_z(obj); 3403 } else { 3404 /* 3405 * Bump the reference counts for objects on this DAG. If 3406 * this is the first dlopen() call for the object that was 3407 * already loaded as a dependency, initialize the dag 3408 * starting at it. 3409 */ 3410 init_dag(obj); 3411 ref_dag(obj); 3412 3413 if ((lo_flags & RTLD_LO_TRACE) != 0) 3414 goto trace; 3415 } 3416 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3417 obj->z_nodelete) && !obj->ref_nodel) { 3418 dbg("obj %s nodelete", obj->path); 3419 ref_dag(obj); 3420 obj->z_nodelete = obj->ref_nodel = true; 3421 } 3422 } 3423 3424 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3425 name); 3426 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3427 3428 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3429 map_stacks_exec(lockstate); 3430 if (obj != NULL) 3431 distribute_static_tls(&initlist, lockstate); 3432 } 3433 3434 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3435 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3436 lockstate) == -1) { 3437 objlist_clear(&initlist); 3438 dlopen_cleanup(obj, lockstate); 3439 if (lockstate == &mlockstate) 3440 lock_release(rtld_bind_lock, lockstate); 3441 return (NULL); 3442 } 3443 3444 if (!(lo_flags & RTLD_LO_EARLY)) { 3445 /* Call the init functions. */ 3446 objlist_call_init(&initlist, lockstate); 3447 } 3448 objlist_clear(&initlist); 3449 if (lockstate == &mlockstate) 3450 lock_release(rtld_bind_lock, lockstate); 3451 return obj; 3452 trace: 3453 trace_loaded_objects(obj); 3454 if (lockstate == &mlockstate) 3455 lock_release(rtld_bind_lock, lockstate); 3456 exit(0); 3457 } 3458 3459 static void * 3460 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3461 int flags) 3462 { 3463 DoneList donelist; 3464 const Obj_Entry *obj, *defobj; 3465 const Elf_Sym *def; 3466 SymLook req; 3467 RtldLockState lockstate; 3468 tls_index ti; 3469 void *sym; 3470 int res; 3471 3472 def = NULL; 3473 defobj = NULL; 3474 symlook_init(&req, name); 3475 req.ventry = ve; 3476 req.flags = flags | SYMLOOK_IN_PLT; 3477 req.lockstate = &lockstate; 3478 3479 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3480 rlock_acquire(rtld_bind_lock, &lockstate); 3481 if (sigsetjmp(lockstate.env, 0) != 0) 3482 lock_upgrade(rtld_bind_lock, &lockstate); 3483 if (handle == NULL || handle == RTLD_NEXT || 3484 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3485 3486 if ((obj = obj_from_addr(retaddr)) == NULL) { 3487 _rtld_error("Cannot determine caller's shared object"); 3488 lock_release(rtld_bind_lock, &lockstate); 3489 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3490 return NULL; 3491 } 3492 if (handle == NULL) { /* Just the caller's shared object. */ 3493 res = symlook_obj(&req, obj); 3494 if (res == 0) { 3495 def = req.sym_out; 3496 defobj = req.defobj_out; 3497 } 3498 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3499 handle == RTLD_SELF) { /* ... caller included */ 3500 if (handle == RTLD_NEXT) 3501 obj = globallist_next(obj); 3502 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3503 if (obj->marker) 3504 continue; 3505 res = symlook_obj(&req, obj); 3506 if (res == 0) { 3507 if (def == NULL || 3508 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3509 def = req.sym_out; 3510 defobj = req.defobj_out; 3511 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3512 break; 3513 } 3514 } 3515 } 3516 /* 3517 * Search the dynamic linker itself, and possibly resolve the 3518 * symbol from there. This is how the application links to 3519 * dynamic linker services such as dlopen. 3520 */ 3521 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3522 res = symlook_obj(&req, &obj_rtld); 3523 if (res == 0) { 3524 def = req.sym_out; 3525 defobj = req.defobj_out; 3526 } 3527 } 3528 } else { 3529 assert(handle == RTLD_DEFAULT); 3530 res = symlook_default(&req, obj); 3531 if (res == 0) { 3532 defobj = req.defobj_out; 3533 def = req.sym_out; 3534 } 3535 } 3536 } else { 3537 if ((obj = dlcheck(handle)) == NULL) { 3538 lock_release(rtld_bind_lock, &lockstate); 3539 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3540 return NULL; 3541 } 3542 3543 donelist_init(&donelist); 3544 if (obj->mainprog) { 3545 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3546 res = symlook_global(&req, &donelist); 3547 if (res == 0) { 3548 def = req.sym_out; 3549 defobj = req.defobj_out; 3550 } 3551 /* 3552 * Search the dynamic linker itself, and possibly resolve the 3553 * symbol from there. This is how the application links to 3554 * dynamic linker services such as dlopen. 3555 */ 3556 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3557 res = symlook_obj(&req, &obj_rtld); 3558 if (res == 0) { 3559 def = req.sym_out; 3560 defobj = req.defobj_out; 3561 } 3562 } 3563 } 3564 else { 3565 /* Search the whole DAG rooted at the given object. */ 3566 res = symlook_list(&req, &obj->dagmembers, &donelist); 3567 if (res == 0) { 3568 def = req.sym_out; 3569 defobj = req.defobj_out; 3570 } 3571 } 3572 } 3573 3574 if (def != NULL) { 3575 lock_release(rtld_bind_lock, &lockstate); 3576 3577 /* 3578 * The value required by the caller is derived from the value 3579 * of the symbol. this is simply the relocated value of the 3580 * symbol. 3581 */ 3582 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3583 sym = make_function_pointer(def, defobj); 3584 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3585 sym = rtld_resolve_ifunc(defobj, def); 3586 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3587 ti.ti_module = defobj->tlsindex; 3588 ti.ti_offset = def->st_value; 3589 sym = __tls_get_addr(&ti); 3590 } else 3591 sym = defobj->relocbase + def->st_value; 3592 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3593 return (sym); 3594 } 3595 3596 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3597 ve != NULL ? ve->name : ""); 3598 lock_release(rtld_bind_lock, &lockstate); 3599 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3600 return NULL; 3601 } 3602 3603 void * 3604 dlsym(void *handle, const char *name) 3605 { 3606 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3607 SYMLOOK_DLSYM); 3608 } 3609 3610 dlfunc_t 3611 dlfunc(void *handle, const char *name) 3612 { 3613 union { 3614 void *d; 3615 dlfunc_t f; 3616 } rv; 3617 3618 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3619 SYMLOOK_DLSYM); 3620 return (rv.f); 3621 } 3622 3623 void * 3624 dlvsym(void *handle, const char *name, const char *version) 3625 { 3626 Ver_Entry ventry; 3627 3628 ventry.name = version; 3629 ventry.file = NULL; 3630 ventry.hash = elf_hash(version); 3631 ventry.flags= 0; 3632 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3633 SYMLOOK_DLSYM); 3634 } 3635 3636 int 3637 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3638 { 3639 const Obj_Entry *obj; 3640 RtldLockState lockstate; 3641 3642 rlock_acquire(rtld_bind_lock, &lockstate); 3643 obj = obj_from_addr(addr); 3644 if (obj == NULL) { 3645 _rtld_error("No shared object contains address"); 3646 lock_release(rtld_bind_lock, &lockstate); 3647 return (0); 3648 } 3649 rtld_fill_dl_phdr_info(obj, phdr_info); 3650 lock_release(rtld_bind_lock, &lockstate); 3651 return (1); 3652 } 3653 3654 int 3655 dladdr(const void *addr, Dl_info *info) 3656 { 3657 const Obj_Entry *obj; 3658 const Elf_Sym *def; 3659 void *symbol_addr; 3660 unsigned long symoffset; 3661 RtldLockState lockstate; 3662 3663 rlock_acquire(rtld_bind_lock, &lockstate); 3664 obj = obj_from_addr(addr); 3665 if (obj == NULL) { 3666 _rtld_error("No shared object contains address"); 3667 lock_release(rtld_bind_lock, &lockstate); 3668 return 0; 3669 } 3670 info->dli_fname = obj->path; 3671 info->dli_fbase = obj->mapbase; 3672 info->dli_saddr = (void *)0; 3673 info->dli_sname = NULL; 3674 3675 /* 3676 * Walk the symbol list looking for the symbol whose address is 3677 * closest to the address sent in. 3678 */ 3679 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3680 def = obj->symtab + symoffset; 3681 3682 /* 3683 * For skip the symbol if st_shndx is either SHN_UNDEF or 3684 * SHN_COMMON. 3685 */ 3686 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3687 continue; 3688 3689 /* 3690 * If the symbol is greater than the specified address, or if it 3691 * is further away from addr than the current nearest symbol, 3692 * then reject it. 3693 */ 3694 symbol_addr = obj->relocbase + def->st_value; 3695 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3696 continue; 3697 3698 /* Update our idea of the nearest symbol. */ 3699 info->dli_sname = obj->strtab + def->st_name; 3700 info->dli_saddr = symbol_addr; 3701 3702 /* Exact match? */ 3703 if (info->dli_saddr == addr) 3704 break; 3705 } 3706 lock_release(rtld_bind_lock, &lockstate); 3707 return 1; 3708 } 3709 3710 int 3711 dlinfo(void *handle, int request, void *p) 3712 { 3713 const Obj_Entry *obj; 3714 RtldLockState lockstate; 3715 int error; 3716 3717 rlock_acquire(rtld_bind_lock, &lockstate); 3718 3719 if (handle == NULL || handle == RTLD_SELF) { 3720 void *retaddr; 3721 3722 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3723 if ((obj = obj_from_addr(retaddr)) == NULL) 3724 _rtld_error("Cannot determine caller's shared object"); 3725 } else 3726 obj = dlcheck(handle); 3727 3728 if (obj == NULL) { 3729 lock_release(rtld_bind_lock, &lockstate); 3730 return (-1); 3731 } 3732 3733 error = 0; 3734 switch (request) { 3735 case RTLD_DI_LINKMAP: 3736 *((struct link_map const **)p) = &obj->linkmap; 3737 break; 3738 case RTLD_DI_ORIGIN: 3739 error = rtld_dirname(obj->path, p); 3740 break; 3741 3742 case RTLD_DI_SERINFOSIZE: 3743 case RTLD_DI_SERINFO: 3744 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3745 break; 3746 3747 default: 3748 _rtld_error("Invalid request %d passed to dlinfo()", request); 3749 error = -1; 3750 } 3751 3752 lock_release(rtld_bind_lock, &lockstate); 3753 3754 return (error); 3755 } 3756 3757 static void 3758 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3759 { 3760 3761 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3762 phdr_info->dlpi_name = obj->path; 3763 phdr_info->dlpi_phdr = obj->phdr; 3764 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3765 phdr_info->dlpi_tls_modid = obj->tlsindex; 3766 phdr_info->dlpi_tls_data = obj->tlsinit; 3767 phdr_info->dlpi_adds = obj_loads; 3768 phdr_info->dlpi_subs = obj_loads - obj_count; 3769 } 3770 3771 int 3772 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3773 { 3774 struct dl_phdr_info phdr_info; 3775 Obj_Entry *obj, marker; 3776 RtldLockState bind_lockstate, phdr_lockstate; 3777 int error; 3778 3779 init_marker(&marker); 3780 error = 0; 3781 3782 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3783 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3784 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3785 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3786 rtld_fill_dl_phdr_info(obj, &phdr_info); 3787 hold_object(obj); 3788 lock_release(rtld_bind_lock, &bind_lockstate); 3789 3790 error = callback(&phdr_info, sizeof phdr_info, param); 3791 3792 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3793 unhold_object(obj); 3794 obj = globallist_next(&marker); 3795 TAILQ_REMOVE(&obj_list, &marker, next); 3796 if (error != 0) { 3797 lock_release(rtld_bind_lock, &bind_lockstate); 3798 lock_release(rtld_phdr_lock, &phdr_lockstate); 3799 return (error); 3800 } 3801 } 3802 3803 if (error == 0) { 3804 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3805 lock_release(rtld_bind_lock, &bind_lockstate); 3806 error = callback(&phdr_info, sizeof(phdr_info), param); 3807 } 3808 lock_release(rtld_phdr_lock, &phdr_lockstate); 3809 return (error); 3810 } 3811 3812 static void * 3813 fill_search_info(const char *dir, size_t dirlen, void *param) 3814 { 3815 struct fill_search_info_args *arg; 3816 3817 arg = param; 3818 3819 if (arg->request == RTLD_DI_SERINFOSIZE) { 3820 arg->serinfo->dls_cnt ++; 3821 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3822 } else { 3823 struct dl_serpath *s_entry; 3824 3825 s_entry = arg->serpath; 3826 s_entry->dls_name = arg->strspace; 3827 s_entry->dls_flags = arg->flags; 3828 3829 strncpy(arg->strspace, dir, dirlen); 3830 arg->strspace[dirlen] = '\0'; 3831 3832 arg->strspace += dirlen + 1; 3833 arg->serpath++; 3834 } 3835 3836 return (NULL); 3837 } 3838 3839 static int 3840 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3841 { 3842 struct dl_serinfo _info; 3843 struct fill_search_info_args args; 3844 3845 args.request = RTLD_DI_SERINFOSIZE; 3846 args.serinfo = &_info; 3847 3848 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3849 _info.dls_cnt = 0; 3850 3851 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3852 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3853 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3854 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3855 if (!obj->z_nodeflib) 3856 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3857 3858 3859 if (request == RTLD_DI_SERINFOSIZE) { 3860 info->dls_size = _info.dls_size; 3861 info->dls_cnt = _info.dls_cnt; 3862 return (0); 3863 } 3864 3865 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3866 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3867 return (-1); 3868 } 3869 3870 args.request = RTLD_DI_SERINFO; 3871 args.serinfo = info; 3872 args.serpath = &info->dls_serpath[0]; 3873 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3874 3875 args.flags = LA_SER_RUNPATH; 3876 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3877 return (-1); 3878 3879 args.flags = LA_SER_LIBPATH; 3880 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3881 return (-1); 3882 3883 args.flags = LA_SER_RUNPATH; 3884 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3885 return (-1); 3886 3887 args.flags = LA_SER_CONFIG; 3888 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3889 != NULL) 3890 return (-1); 3891 3892 args.flags = LA_SER_DEFAULT; 3893 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3894 fill_search_info, NULL, &args) != NULL) 3895 return (-1); 3896 return (0); 3897 } 3898 3899 static int 3900 rtld_dirname(const char *path, char *bname) 3901 { 3902 const char *endp; 3903 3904 /* Empty or NULL string gets treated as "." */ 3905 if (path == NULL || *path == '\0') { 3906 bname[0] = '.'; 3907 bname[1] = '\0'; 3908 return (0); 3909 } 3910 3911 /* Strip trailing slashes */ 3912 endp = path + strlen(path) - 1; 3913 while (endp > path && *endp == '/') 3914 endp--; 3915 3916 /* Find the start of the dir */ 3917 while (endp > path && *endp != '/') 3918 endp--; 3919 3920 /* Either the dir is "/" or there are no slashes */ 3921 if (endp == path) { 3922 bname[0] = *endp == '/' ? '/' : '.'; 3923 bname[1] = '\0'; 3924 return (0); 3925 } else { 3926 do { 3927 endp--; 3928 } while (endp > path && *endp == '/'); 3929 } 3930 3931 if (endp - path + 2 > PATH_MAX) 3932 { 3933 _rtld_error("Filename is too long: %s", path); 3934 return(-1); 3935 } 3936 3937 strncpy(bname, path, endp - path + 1); 3938 bname[endp - path + 1] = '\0'; 3939 return (0); 3940 } 3941 3942 static int 3943 rtld_dirname_abs(const char *path, char *base) 3944 { 3945 char *last; 3946 3947 if (realpath(path, base) == NULL) 3948 return (-1); 3949 dbg("%s -> %s", path, base); 3950 last = strrchr(base, '/'); 3951 if (last == NULL) 3952 return (-1); 3953 if (last != base) 3954 *last = '\0'; 3955 return (0); 3956 } 3957 3958 static void 3959 linkmap_add(Obj_Entry *obj) 3960 { 3961 struct link_map *l = &obj->linkmap; 3962 struct link_map *prev; 3963 3964 obj->linkmap.l_name = obj->path; 3965 obj->linkmap.l_addr = obj->mapbase; 3966 obj->linkmap.l_ld = obj->dynamic; 3967 #ifdef __mips__ 3968 /* GDB needs load offset on MIPS to use the symbols */ 3969 obj->linkmap.l_offs = obj->relocbase; 3970 #endif 3971 3972 if (r_debug.r_map == NULL) { 3973 r_debug.r_map = l; 3974 return; 3975 } 3976 3977 /* 3978 * Scan to the end of the list, but not past the entry for the 3979 * dynamic linker, which we want to keep at the very end. 3980 */ 3981 for (prev = r_debug.r_map; 3982 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3983 prev = prev->l_next) 3984 ; 3985 3986 /* Link in the new entry. */ 3987 l->l_prev = prev; 3988 l->l_next = prev->l_next; 3989 if (l->l_next != NULL) 3990 l->l_next->l_prev = l; 3991 prev->l_next = l; 3992 } 3993 3994 static void 3995 linkmap_delete(Obj_Entry *obj) 3996 { 3997 struct link_map *l = &obj->linkmap; 3998 3999 if (l->l_prev == NULL) { 4000 if ((r_debug.r_map = l->l_next) != NULL) 4001 l->l_next->l_prev = NULL; 4002 return; 4003 } 4004 4005 if ((l->l_prev->l_next = l->l_next) != NULL) 4006 l->l_next->l_prev = l->l_prev; 4007 } 4008 4009 /* 4010 * Function for the debugger to set a breakpoint on to gain control. 4011 * 4012 * The two parameters allow the debugger to easily find and determine 4013 * what the runtime loader is doing and to whom it is doing it. 4014 * 4015 * When the loadhook trap is hit (r_debug_state, set at program 4016 * initialization), the arguments can be found on the stack: 4017 * 4018 * +8 struct link_map *m 4019 * +4 struct r_debug *rd 4020 * +0 RetAddr 4021 */ 4022 void 4023 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4024 { 4025 /* 4026 * The following is a hack to force the compiler to emit calls to 4027 * this function, even when optimizing. If the function is empty, 4028 * the compiler is not obliged to emit any code for calls to it, 4029 * even when marked __noinline. However, gdb depends on those 4030 * calls being made. 4031 */ 4032 __compiler_membar(); 4033 } 4034 4035 /* 4036 * A function called after init routines have completed. This can be used to 4037 * break before a program's entry routine is called, and can be used when 4038 * main is not available in the symbol table. 4039 */ 4040 void 4041 _r_debug_postinit(struct link_map *m __unused) 4042 { 4043 4044 /* See r_debug_state(). */ 4045 __compiler_membar(); 4046 } 4047 4048 static void 4049 release_object(Obj_Entry *obj) 4050 { 4051 4052 if (obj->holdcount > 0) { 4053 obj->unholdfree = true; 4054 return; 4055 } 4056 munmap(obj->mapbase, obj->mapsize); 4057 linkmap_delete(obj); 4058 obj_free(obj); 4059 } 4060 4061 /* 4062 * Get address of the pointer variable in the main program. 4063 * Prefer non-weak symbol over the weak one. 4064 */ 4065 static const void ** 4066 get_program_var_addr(const char *name, RtldLockState *lockstate) 4067 { 4068 SymLook req; 4069 DoneList donelist; 4070 4071 symlook_init(&req, name); 4072 req.lockstate = lockstate; 4073 donelist_init(&donelist); 4074 if (symlook_global(&req, &donelist) != 0) 4075 return (NULL); 4076 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4077 return ((const void **)make_function_pointer(req.sym_out, 4078 req.defobj_out)); 4079 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4080 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4081 else 4082 return ((const void **)(req.defobj_out->relocbase + 4083 req.sym_out->st_value)); 4084 } 4085 4086 /* 4087 * Set a pointer variable in the main program to the given value. This 4088 * is used to set key variables such as "environ" before any of the 4089 * init functions are called. 4090 */ 4091 static void 4092 set_program_var(const char *name, const void *value) 4093 { 4094 const void **addr; 4095 4096 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4097 dbg("\"%s\": *%p <-- %p", name, addr, value); 4098 *addr = value; 4099 } 4100 } 4101 4102 /* 4103 * Search the global objects, including dependencies and main object, 4104 * for the given symbol. 4105 */ 4106 static int 4107 symlook_global(SymLook *req, DoneList *donelist) 4108 { 4109 SymLook req1; 4110 const Objlist_Entry *elm; 4111 int res; 4112 4113 symlook_init_from_req(&req1, req); 4114 4115 /* Search all objects loaded at program start up. */ 4116 if (req->defobj_out == NULL || 4117 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4118 res = symlook_list(&req1, &list_main, donelist); 4119 if (res == 0 && (req->defobj_out == NULL || 4120 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4121 req->sym_out = req1.sym_out; 4122 req->defobj_out = req1.defobj_out; 4123 assert(req->defobj_out != NULL); 4124 } 4125 } 4126 4127 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4128 STAILQ_FOREACH(elm, &list_global, link) { 4129 if (req->defobj_out != NULL && 4130 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4131 break; 4132 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4133 if (res == 0 && (req->defobj_out == NULL || 4134 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4135 req->sym_out = req1.sym_out; 4136 req->defobj_out = req1.defobj_out; 4137 assert(req->defobj_out != NULL); 4138 } 4139 } 4140 4141 return (req->sym_out != NULL ? 0 : ESRCH); 4142 } 4143 4144 /* 4145 * Given a symbol name in a referencing object, find the corresponding 4146 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4147 * no definition was found. Returns a pointer to the Obj_Entry of the 4148 * defining object via the reference parameter DEFOBJ_OUT. 4149 */ 4150 static int 4151 symlook_default(SymLook *req, const Obj_Entry *refobj) 4152 { 4153 DoneList donelist; 4154 const Objlist_Entry *elm; 4155 SymLook req1; 4156 int res; 4157 4158 donelist_init(&donelist); 4159 symlook_init_from_req(&req1, req); 4160 4161 /* 4162 * Look first in the referencing object if linked symbolically, 4163 * and similarly handle protected symbols. 4164 */ 4165 res = symlook_obj(&req1, refobj); 4166 if (res == 0 && (refobj->symbolic || 4167 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4168 req->sym_out = req1.sym_out; 4169 req->defobj_out = req1.defobj_out; 4170 assert(req->defobj_out != NULL); 4171 } 4172 if (refobj->symbolic || req->defobj_out != NULL) 4173 donelist_check(&donelist, refobj); 4174 4175 symlook_global(req, &donelist); 4176 4177 /* Search all dlopened DAGs containing the referencing object. */ 4178 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4179 if (req->sym_out != NULL && 4180 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4181 break; 4182 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4183 if (res == 0 && (req->sym_out == NULL || 4184 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4185 req->sym_out = req1.sym_out; 4186 req->defobj_out = req1.defobj_out; 4187 assert(req->defobj_out != NULL); 4188 } 4189 } 4190 4191 /* 4192 * Search the dynamic linker itself, and possibly resolve the 4193 * symbol from there. This is how the application links to 4194 * dynamic linker services such as dlopen. 4195 */ 4196 if (req->sym_out == NULL || 4197 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4198 res = symlook_obj(&req1, &obj_rtld); 4199 if (res == 0) { 4200 req->sym_out = req1.sym_out; 4201 req->defobj_out = req1.defobj_out; 4202 assert(req->defobj_out != NULL); 4203 } 4204 } 4205 4206 return (req->sym_out != NULL ? 0 : ESRCH); 4207 } 4208 4209 static int 4210 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4211 { 4212 const Elf_Sym *def; 4213 const Obj_Entry *defobj; 4214 const Objlist_Entry *elm; 4215 SymLook req1; 4216 int res; 4217 4218 def = NULL; 4219 defobj = NULL; 4220 STAILQ_FOREACH(elm, objlist, link) { 4221 if (donelist_check(dlp, elm->obj)) 4222 continue; 4223 symlook_init_from_req(&req1, req); 4224 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4225 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4226 def = req1.sym_out; 4227 defobj = req1.defobj_out; 4228 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4229 break; 4230 } 4231 } 4232 } 4233 if (def != NULL) { 4234 req->sym_out = def; 4235 req->defobj_out = defobj; 4236 return (0); 4237 } 4238 return (ESRCH); 4239 } 4240 4241 /* 4242 * Search the chain of DAGS cointed to by the given Needed_Entry 4243 * for a symbol of the given name. Each DAG is scanned completely 4244 * before advancing to the next one. Returns a pointer to the symbol, 4245 * or NULL if no definition was found. 4246 */ 4247 static int 4248 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4249 { 4250 const Elf_Sym *def; 4251 const Needed_Entry *n; 4252 const Obj_Entry *defobj; 4253 SymLook req1; 4254 int res; 4255 4256 def = NULL; 4257 defobj = NULL; 4258 symlook_init_from_req(&req1, req); 4259 for (n = needed; n != NULL; n = n->next) { 4260 if (n->obj == NULL || 4261 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4262 continue; 4263 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4264 def = req1.sym_out; 4265 defobj = req1.defobj_out; 4266 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4267 break; 4268 } 4269 } 4270 if (def != NULL) { 4271 req->sym_out = def; 4272 req->defobj_out = defobj; 4273 return (0); 4274 } 4275 return (ESRCH); 4276 } 4277 4278 /* 4279 * Search the symbol table of a single shared object for a symbol of 4280 * the given name and version, if requested. Returns a pointer to the 4281 * symbol, or NULL if no definition was found. If the object is 4282 * filter, return filtered symbol from filtee. 4283 * 4284 * The symbol's hash value is passed in for efficiency reasons; that 4285 * eliminates many recomputations of the hash value. 4286 */ 4287 int 4288 symlook_obj(SymLook *req, const Obj_Entry *obj) 4289 { 4290 DoneList donelist; 4291 SymLook req1; 4292 int flags, res, mres; 4293 4294 /* 4295 * If there is at least one valid hash at this point, we prefer to 4296 * use the faster GNU version if available. 4297 */ 4298 if (obj->valid_hash_gnu) 4299 mres = symlook_obj1_gnu(req, obj); 4300 else if (obj->valid_hash_sysv) 4301 mres = symlook_obj1_sysv(req, obj); 4302 else 4303 return (EINVAL); 4304 4305 if (mres == 0) { 4306 if (obj->needed_filtees != NULL) { 4307 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4308 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4309 donelist_init(&donelist); 4310 symlook_init_from_req(&req1, req); 4311 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4312 if (res == 0) { 4313 req->sym_out = req1.sym_out; 4314 req->defobj_out = req1.defobj_out; 4315 } 4316 return (res); 4317 } 4318 if (obj->needed_aux_filtees != NULL) { 4319 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4320 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4321 donelist_init(&donelist); 4322 symlook_init_from_req(&req1, req); 4323 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4324 if (res == 0) { 4325 req->sym_out = req1.sym_out; 4326 req->defobj_out = req1.defobj_out; 4327 return (res); 4328 } 4329 } 4330 } 4331 return (mres); 4332 } 4333 4334 /* Symbol match routine common to both hash functions */ 4335 static bool 4336 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4337 const unsigned long symnum) 4338 { 4339 Elf_Versym verndx; 4340 const Elf_Sym *symp; 4341 const char *strp; 4342 4343 symp = obj->symtab + symnum; 4344 strp = obj->strtab + symp->st_name; 4345 4346 switch (ELF_ST_TYPE(symp->st_info)) { 4347 case STT_FUNC: 4348 case STT_NOTYPE: 4349 case STT_OBJECT: 4350 case STT_COMMON: 4351 case STT_GNU_IFUNC: 4352 if (symp->st_value == 0) 4353 return (false); 4354 /* fallthrough */ 4355 case STT_TLS: 4356 if (symp->st_shndx != SHN_UNDEF) 4357 break; 4358 #ifndef __mips__ 4359 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4360 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4361 break; 4362 #endif 4363 /* fallthrough */ 4364 default: 4365 return (false); 4366 } 4367 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4368 return (false); 4369 4370 if (req->ventry == NULL) { 4371 if (obj->versyms != NULL) { 4372 verndx = VER_NDX(obj->versyms[symnum]); 4373 if (verndx > obj->vernum) { 4374 _rtld_error( 4375 "%s: symbol %s references wrong version %d", 4376 obj->path, obj->strtab + symnum, verndx); 4377 return (false); 4378 } 4379 /* 4380 * If we are not called from dlsym (i.e. this 4381 * is a normal relocation from unversioned 4382 * binary), accept the symbol immediately if 4383 * it happens to have first version after this 4384 * shared object became versioned. Otherwise, 4385 * if symbol is versioned and not hidden, 4386 * remember it. If it is the only symbol with 4387 * this name exported by the shared object, it 4388 * will be returned as a match by the calling 4389 * function. If symbol is global (verndx < 2) 4390 * accept it unconditionally. 4391 */ 4392 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4393 verndx == VER_NDX_GIVEN) { 4394 result->sym_out = symp; 4395 return (true); 4396 } 4397 else if (verndx >= VER_NDX_GIVEN) { 4398 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4399 == 0) { 4400 if (result->vsymp == NULL) 4401 result->vsymp = symp; 4402 result->vcount++; 4403 } 4404 return (false); 4405 } 4406 } 4407 result->sym_out = symp; 4408 return (true); 4409 } 4410 if (obj->versyms == NULL) { 4411 if (object_match_name(obj, req->ventry->name)) { 4412 _rtld_error("%s: object %s should provide version %s " 4413 "for symbol %s", obj_rtld.path, obj->path, 4414 req->ventry->name, obj->strtab + symnum); 4415 return (false); 4416 } 4417 } else { 4418 verndx = VER_NDX(obj->versyms[symnum]); 4419 if (verndx > obj->vernum) { 4420 _rtld_error("%s: symbol %s references wrong version %d", 4421 obj->path, obj->strtab + symnum, verndx); 4422 return (false); 4423 } 4424 if (obj->vertab[verndx].hash != req->ventry->hash || 4425 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4426 /* 4427 * Version does not match. Look if this is a 4428 * global symbol and if it is not hidden. If 4429 * global symbol (verndx < 2) is available, 4430 * use it. Do not return symbol if we are 4431 * called by dlvsym, because dlvsym looks for 4432 * a specific version and default one is not 4433 * what dlvsym wants. 4434 */ 4435 if ((req->flags & SYMLOOK_DLSYM) || 4436 (verndx >= VER_NDX_GIVEN) || 4437 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4438 return (false); 4439 } 4440 } 4441 result->sym_out = symp; 4442 return (true); 4443 } 4444 4445 /* 4446 * Search for symbol using SysV hash function. 4447 * obj->buckets is known not to be NULL at this point; the test for this was 4448 * performed with the obj->valid_hash_sysv assignment. 4449 */ 4450 static int 4451 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4452 { 4453 unsigned long symnum; 4454 Sym_Match_Result matchres; 4455 4456 matchres.sym_out = NULL; 4457 matchres.vsymp = NULL; 4458 matchres.vcount = 0; 4459 4460 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4461 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4462 if (symnum >= obj->nchains) 4463 return (ESRCH); /* Bad object */ 4464 4465 if (matched_symbol(req, obj, &matchres, symnum)) { 4466 req->sym_out = matchres.sym_out; 4467 req->defobj_out = obj; 4468 return (0); 4469 } 4470 } 4471 if (matchres.vcount == 1) { 4472 req->sym_out = matchres.vsymp; 4473 req->defobj_out = obj; 4474 return (0); 4475 } 4476 return (ESRCH); 4477 } 4478 4479 /* Search for symbol using GNU hash function */ 4480 static int 4481 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4482 { 4483 Elf_Addr bloom_word; 4484 const Elf32_Word *hashval; 4485 Elf32_Word bucket; 4486 Sym_Match_Result matchres; 4487 unsigned int h1, h2; 4488 unsigned long symnum; 4489 4490 matchres.sym_out = NULL; 4491 matchres.vsymp = NULL; 4492 matchres.vcount = 0; 4493 4494 /* Pick right bitmask word from Bloom filter array */ 4495 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4496 obj->maskwords_bm_gnu]; 4497 4498 /* Calculate modulus word size of gnu hash and its derivative */ 4499 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4500 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4501 4502 /* Filter out the "definitely not in set" queries */ 4503 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4504 return (ESRCH); 4505 4506 /* Locate hash chain and corresponding value element*/ 4507 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4508 if (bucket == 0) 4509 return (ESRCH); 4510 hashval = &obj->chain_zero_gnu[bucket]; 4511 do { 4512 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4513 symnum = hashval - obj->chain_zero_gnu; 4514 if (matched_symbol(req, obj, &matchres, symnum)) { 4515 req->sym_out = matchres.sym_out; 4516 req->defobj_out = obj; 4517 return (0); 4518 } 4519 } 4520 } while ((*hashval++ & 1) == 0); 4521 if (matchres.vcount == 1) { 4522 req->sym_out = matchres.vsymp; 4523 req->defobj_out = obj; 4524 return (0); 4525 } 4526 return (ESRCH); 4527 } 4528 4529 static void 4530 trace_loaded_objects(Obj_Entry *obj) 4531 { 4532 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4533 int c; 4534 4535 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4536 main_local = ""; 4537 4538 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4539 fmt1 = "\t%o => %p (%x)\n"; 4540 4541 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4542 fmt2 = "\t%o (%x)\n"; 4543 4544 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4545 4546 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4547 Needed_Entry *needed; 4548 const char *name, *path; 4549 bool is_lib; 4550 4551 if (obj->marker) 4552 continue; 4553 if (list_containers && obj->needed != NULL) 4554 rtld_printf("%s:\n", obj->path); 4555 for (needed = obj->needed; needed; needed = needed->next) { 4556 if (needed->obj != NULL) { 4557 if (needed->obj->traced && !list_containers) 4558 continue; 4559 needed->obj->traced = true; 4560 path = needed->obj->path; 4561 } else 4562 path = "not found"; 4563 4564 name = obj->strtab + needed->name; 4565 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4566 4567 fmt = is_lib ? fmt1 : fmt2; 4568 while ((c = *fmt++) != '\0') { 4569 switch (c) { 4570 default: 4571 rtld_putchar(c); 4572 continue; 4573 case '\\': 4574 switch (c = *fmt) { 4575 case '\0': 4576 continue; 4577 case 'n': 4578 rtld_putchar('\n'); 4579 break; 4580 case 't': 4581 rtld_putchar('\t'); 4582 break; 4583 } 4584 break; 4585 case '%': 4586 switch (c = *fmt) { 4587 case '\0': 4588 continue; 4589 case '%': 4590 default: 4591 rtld_putchar(c); 4592 break; 4593 case 'A': 4594 rtld_putstr(main_local); 4595 break; 4596 case 'a': 4597 rtld_putstr(obj_main->path); 4598 break; 4599 case 'o': 4600 rtld_putstr(name); 4601 break; 4602 #if 0 4603 case 'm': 4604 rtld_printf("%d", sodp->sod_major); 4605 break; 4606 case 'n': 4607 rtld_printf("%d", sodp->sod_minor); 4608 break; 4609 #endif 4610 case 'p': 4611 rtld_putstr(path); 4612 break; 4613 case 'x': 4614 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4615 0); 4616 break; 4617 } 4618 break; 4619 } 4620 ++fmt; 4621 } 4622 } 4623 } 4624 } 4625 4626 /* 4627 * Unload a dlopened object and its dependencies from memory and from 4628 * our data structures. It is assumed that the DAG rooted in the 4629 * object has already been unreferenced, and that the object has a 4630 * reference count of 0. 4631 */ 4632 static void 4633 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4634 { 4635 Obj_Entry marker, *obj, *next; 4636 4637 assert(root->refcount == 0); 4638 4639 /* 4640 * Pass over the DAG removing unreferenced objects from 4641 * appropriate lists. 4642 */ 4643 unlink_object(root); 4644 4645 /* Unmap all objects that are no longer referenced. */ 4646 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4647 next = TAILQ_NEXT(obj, next); 4648 if (obj->marker || obj->refcount != 0) 4649 continue; 4650 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4651 obj->mapsize, 0, obj->path); 4652 dbg("unloading \"%s\"", obj->path); 4653 /* 4654 * Unlink the object now to prevent new references from 4655 * being acquired while the bind lock is dropped in 4656 * recursive dlclose() invocations. 4657 */ 4658 TAILQ_REMOVE(&obj_list, obj, next); 4659 obj_count--; 4660 4661 if (obj->filtees_loaded) { 4662 if (next != NULL) { 4663 init_marker(&marker); 4664 TAILQ_INSERT_BEFORE(next, &marker, next); 4665 unload_filtees(obj, lockstate); 4666 next = TAILQ_NEXT(&marker, next); 4667 TAILQ_REMOVE(&obj_list, &marker, next); 4668 } else 4669 unload_filtees(obj, lockstate); 4670 } 4671 release_object(obj); 4672 } 4673 } 4674 4675 static void 4676 unlink_object(Obj_Entry *root) 4677 { 4678 Objlist_Entry *elm; 4679 4680 if (root->refcount == 0) { 4681 /* Remove the object from the RTLD_GLOBAL list. */ 4682 objlist_remove(&list_global, root); 4683 4684 /* Remove the object from all objects' DAG lists. */ 4685 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4686 objlist_remove(&elm->obj->dldags, root); 4687 if (elm->obj != root) 4688 unlink_object(elm->obj); 4689 } 4690 } 4691 } 4692 4693 static void 4694 ref_dag(Obj_Entry *root) 4695 { 4696 Objlist_Entry *elm; 4697 4698 assert(root->dag_inited); 4699 STAILQ_FOREACH(elm, &root->dagmembers, link) 4700 elm->obj->refcount++; 4701 } 4702 4703 static void 4704 unref_dag(Obj_Entry *root) 4705 { 4706 Objlist_Entry *elm; 4707 4708 assert(root->dag_inited); 4709 STAILQ_FOREACH(elm, &root->dagmembers, link) 4710 elm->obj->refcount--; 4711 } 4712 4713 /* 4714 * Common code for MD __tls_get_addr(). 4715 */ 4716 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4717 static void * 4718 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4719 { 4720 Elf_Addr *newdtv, *dtv; 4721 RtldLockState lockstate; 4722 int to_copy; 4723 4724 dtv = *dtvp; 4725 /* Check dtv generation in case new modules have arrived */ 4726 if (dtv[0] != tls_dtv_generation) { 4727 wlock_acquire(rtld_bind_lock, &lockstate); 4728 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4729 to_copy = dtv[1]; 4730 if (to_copy > tls_max_index) 4731 to_copy = tls_max_index; 4732 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4733 newdtv[0] = tls_dtv_generation; 4734 newdtv[1] = tls_max_index; 4735 free(dtv); 4736 lock_release(rtld_bind_lock, &lockstate); 4737 dtv = *dtvp = newdtv; 4738 } 4739 4740 /* Dynamically allocate module TLS if necessary */ 4741 if (dtv[index + 1] == 0) { 4742 /* Signal safe, wlock will block out signals. */ 4743 wlock_acquire(rtld_bind_lock, &lockstate); 4744 if (!dtv[index + 1]) 4745 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4746 lock_release(rtld_bind_lock, &lockstate); 4747 } 4748 return ((void *)(dtv[index + 1] + offset)); 4749 } 4750 4751 void * 4752 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4753 { 4754 Elf_Addr *dtv; 4755 4756 dtv = *dtvp; 4757 /* Check dtv generation in case new modules have arrived */ 4758 if (__predict_true(dtv[0] == tls_dtv_generation && 4759 dtv[index + 1] != 0)) 4760 return ((void *)(dtv[index + 1] + offset)); 4761 return (tls_get_addr_slow(dtvp, index, offset)); 4762 } 4763 4764 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4765 defined(__powerpc__) || defined(__riscv) 4766 4767 /* 4768 * Return pointer to allocated TLS block 4769 */ 4770 static void * 4771 get_tls_block_ptr(void *tcb, size_t tcbsize) 4772 { 4773 size_t extra_size, post_size, pre_size, tls_block_size; 4774 size_t tls_init_align; 4775 4776 tls_init_align = MAX(obj_main->tlsalign, 1); 4777 4778 /* Compute fragments sizes. */ 4779 extra_size = tcbsize - TLS_TCB_SIZE; 4780 post_size = calculate_tls_post_size(tls_init_align); 4781 tls_block_size = tcbsize + post_size; 4782 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4783 4784 return ((char *)tcb - pre_size - extra_size); 4785 } 4786 4787 /* 4788 * Allocate Static TLS using the Variant I method. 4789 * 4790 * For details on the layout, see lib/libc/gen/tls.c. 4791 * 4792 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4793 * it is based on tls_last_offset, and TLS offsets here are really TCB 4794 * offsets, whereas libc's tls_static_space is just the executable's static 4795 * TLS segment. 4796 */ 4797 void * 4798 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4799 { 4800 Obj_Entry *obj; 4801 char *tls_block; 4802 Elf_Addr *dtv, **tcb; 4803 Elf_Addr addr; 4804 Elf_Addr i; 4805 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4806 size_t tls_init_align; 4807 4808 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4809 return (oldtcb); 4810 4811 assert(tcbsize >= TLS_TCB_SIZE); 4812 maxalign = MAX(tcbalign, tls_static_max_align); 4813 tls_init_align = MAX(obj_main->tlsalign, 1); 4814 4815 /* Compute fragmets sizes. */ 4816 extra_size = tcbsize - TLS_TCB_SIZE; 4817 post_size = calculate_tls_post_size(tls_init_align); 4818 tls_block_size = tcbsize + post_size; 4819 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4820 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4821 4822 /* Allocate whole TLS block */ 4823 tls_block = malloc_aligned(tls_block_size, maxalign); 4824 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4825 4826 if (oldtcb != NULL) { 4827 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4828 tls_static_space); 4829 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4830 4831 /* Adjust the DTV. */ 4832 dtv = tcb[0]; 4833 for (i = 0; i < dtv[1]; i++) { 4834 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4835 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4836 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4837 } 4838 } 4839 } else { 4840 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4841 tcb[0] = dtv; 4842 dtv[0] = tls_dtv_generation; 4843 dtv[1] = tls_max_index; 4844 4845 for (obj = globallist_curr(objs); obj != NULL; 4846 obj = globallist_next(obj)) { 4847 if (obj->tlsoffset > 0) { 4848 addr = (Elf_Addr)tcb + obj->tlsoffset; 4849 if (obj->tlsinitsize > 0) 4850 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4851 if (obj->tlssize > obj->tlsinitsize) 4852 memset((void*)(addr + obj->tlsinitsize), 0, 4853 obj->tlssize - obj->tlsinitsize); 4854 dtv[obj->tlsindex + 1] = addr; 4855 } 4856 } 4857 } 4858 4859 return (tcb); 4860 } 4861 4862 void 4863 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4864 { 4865 Elf_Addr *dtv; 4866 Elf_Addr tlsstart, tlsend; 4867 size_t post_size; 4868 size_t dtvsize, i, tls_init_align; 4869 4870 assert(tcbsize >= TLS_TCB_SIZE); 4871 tls_init_align = MAX(obj_main->tlsalign, 1); 4872 4873 /* Compute fragments sizes. */ 4874 post_size = calculate_tls_post_size(tls_init_align); 4875 4876 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4877 tlsend = (Elf_Addr)tcb + tls_static_space; 4878 4879 dtv = *(Elf_Addr **)tcb; 4880 dtvsize = dtv[1]; 4881 for (i = 0; i < dtvsize; i++) { 4882 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4883 free((void*)dtv[i+2]); 4884 } 4885 } 4886 free(dtv); 4887 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4888 } 4889 4890 #endif 4891 4892 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4893 4894 /* 4895 * Allocate Static TLS using the Variant II method. 4896 */ 4897 void * 4898 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4899 { 4900 Obj_Entry *obj; 4901 size_t size, ralign; 4902 char *tls; 4903 Elf_Addr *dtv, *olddtv; 4904 Elf_Addr segbase, oldsegbase, addr; 4905 size_t i; 4906 4907 ralign = tcbalign; 4908 if (tls_static_max_align > ralign) 4909 ralign = tls_static_max_align; 4910 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4911 4912 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4913 tls = malloc_aligned(size, ralign); 4914 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4915 4916 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4917 ((Elf_Addr*)segbase)[0] = segbase; 4918 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4919 4920 dtv[0] = tls_dtv_generation; 4921 dtv[1] = tls_max_index; 4922 4923 if (oldtls) { 4924 /* 4925 * Copy the static TLS block over whole. 4926 */ 4927 oldsegbase = (Elf_Addr) oldtls; 4928 memcpy((void *)(segbase - tls_static_space), 4929 (const void *)(oldsegbase - tls_static_space), 4930 tls_static_space); 4931 4932 /* 4933 * If any dynamic TLS blocks have been created tls_get_addr(), 4934 * move them over. 4935 */ 4936 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4937 for (i = 0; i < olddtv[1]; i++) { 4938 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4939 dtv[i+2] = olddtv[i+2]; 4940 olddtv[i+2] = 0; 4941 } 4942 } 4943 4944 /* 4945 * We assume that this block was the one we created with 4946 * allocate_initial_tls(). 4947 */ 4948 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4949 } else { 4950 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4951 if (obj->marker || obj->tlsoffset == 0) 4952 continue; 4953 addr = segbase - obj->tlsoffset; 4954 memset((void*)(addr + obj->tlsinitsize), 4955 0, obj->tlssize - obj->tlsinitsize); 4956 if (obj->tlsinit) { 4957 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4958 obj->static_tls_copied = true; 4959 } 4960 dtv[obj->tlsindex + 1] = addr; 4961 } 4962 } 4963 4964 return (void*) segbase; 4965 } 4966 4967 void 4968 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 4969 { 4970 Elf_Addr* dtv; 4971 size_t size, ralign; 4972 int dtvsize, i; 4973 Elf_Addr tlsstart, tlsend; 4974 4975 /* 4976 * Figure out the size of the initial TLS block so that we can 4977 * find stuff which ___tls_get_addr() allocated dynamically. 4978 */ 4979 ralign = tcbalign; 4980 if (tls_static_max_align > ralign) 4981 ralign = tls_static_max_align; 4982 size = round(tls_static_space, ralign); 4983 4984 dtv = ((Elf_Addr**)tls)[1]; 4985 dtvsize = dtv[1]; 4986 tlsend = (Elf_Addr) tls; 4987 tlsstart = tlsend - size; 4988 for (i = 0; i < dtvsize; i++) { 4989 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4990 free_aligned((void *)dtv[i + 2]); 4991 } 4992 } 4993 4994 free_aligned((void *)tlsstart); 4995 free((void*) dtv); 4996 } 4997 4998 #endif 4999 5000 /* 5001 * Allocate TLS block for module with given index. 5002 */ 5003 void * 5004 allocate_module_tls(int index) 5005 { 5006 Obj_Entry* obj; 5007 char* p; 5008 5009 TAILQ_FOREACH(obj, &obj_list, next) { 5010 if (obj->marker) 5011 continue; 5012 if (obj->tlsindex == index) 5013 break; 5014 } 5015 if (!obj) { 5016 _rtld_error("Can't find module with TLS index %d", index); 5017 rtld_die(); 5018 } 5019 5020 p = malloc_aligned(obj->tlssize, obj->tlsalign); 5021 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5022 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5023 5024 return p; 5025 } 5026 5027 bool 5028 allocate_tls_offset(Obj_Entry *obj) 5029 { 5030 size_t off; 5031 5032 if (obj->tls_done) 5033 return true; 5034 5035 if (obj->tlssize == 0) { 5036 obj->tls_done = true; 5037 return true; 5038 } 5039 5040 if (tls_last_offset == 0) 5041 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5042 else 5043 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5044 obj->tlssize, obj->tlsalign); 5045 5046 /* 5047 * If we have already fixed the size of the static TLS block, we 5048 * must stay within that size. When allocating the static TLS, we 5049 * leave a small amount of space spare to be used for dynamically 5050 * loading modules which use static TLS. 5051 */ 5052 if (tls_static_space != 0) { 5053 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5054 return false; 5055 } else if (obj->tlsalign > tls_static_max_align) { 5056 tls_static_max_align = obj->tlsalign; 5057 } 5058 5059 tls_last_offset = obj->tlsoffset = off; 5060 tls_last_size = obj->tlssize; 5061 obj->tls_done = true; 5062 5063 return true; 5064 } 5065 5066 void 5067 free_tls_offset(Obj_Entry *obj) 5068 { 5069 5070 /* 5071 * If we were the last thing to allocate out of the static TLS 5072 * block, we give our space back to the 'allocator'. This is a 5073 * simplistic workaround to allow libGL.so.1 to be loaded and 5074 * unloaded multiple times. 5075 */ 5076 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5077 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5078 tls_last_offset -= obj->tlssize; 5079 tls_last_size = 0; 5080 } 5081 } 5082 5083 void * 5084 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5085 { 5086 void *ret; 5087 RtldLockState lockstate; 5088 5089 wlock_acquire(rtld_bind_lock, &lockstate); 5090 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5091 tcbsize, tcbalign); 5092 lock_release(rtld_bind_lock, &lockstate); 5093 return (ret); 5094 } 5095 5096 void 5097 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5098 { 5099 RtldLockState lockstate; 5100 5101 wlock_acquire(rtld_bind_lock, &lockstate); 5102 free_tls(tcb, tcbsize, tcbalign); 5103 lock_release(rtld_bind_lock, &lockstate); 5104 } 5105 5106 static void 5107 object_add_name(Obj_Entry *obj, const char *name) 5108 { 5109 Name_Entry *entry; 5110 size_t len; 5111 5112 len = strlen(name); 5113 entry = malloc(sizeof(Name_Entry) + len); 5114 5115 if (entry != NULL) { 5116 strcpy(entry->name, name); 5117 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5118 } 5119 } 5120 5121 static int 5122 object_match_name(const Obj_Entry *obj, const char *name) 5123 { 5124 Name_Entry *entry; 5125 5126 STAILQ_FOREACH(entry, &obj->names, link) { 5127 if (strcmp(name, entry->name) == 0) 5128 return (1); 5129 } 5130 return (0); 5131 } 5132 5133 static Obj_Entry * 5134 locate_dependency(const Obj_Entry *obj, const char *name) 5135 { 5136 const Objlist_Entry *entry; 5137 const Needed_Entry *needed; 5138 5139 STAILQ_FOREACH(entry, &list_main, link) { 5140 if (object_match_name(entry->obj, name)) 5141 return entry->obj; 5142 } 5143 5144 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5145 if (strcmp(obj->strtab + needed->name, name) == 0 || 5146 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5147 /* 5148 * If there is DT_NEEDED for the name we are looking for, 5149 * we are all set. Note that object might not be found if 5150 * dependency was not loaded yet, so the function can 5151 * return NULL here. This is expected and handled 5152 * properly by the caller. 5153 */ 5154 return (needed->obj); 5155 } 5156 } 5157 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5158 obj->path, name); 5159 rtld_die(); 5160 } 5161 5162 static int 5163 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5164 const Elf_Vernaux *vna) 5165 { 5166 const Elf_Verdef *vd; 5167 const char *vername; 5168 5169 vername = refobj->strtab + vna->vna_name; 5170 vd = depobj->verdef; 5171 if (vd == NULL) { 5172 _rtld_error("%s: version %s required by %s not defined", 5173 depobj->path, vername, refobj->path); 5174 return (-1); 5175 } 5176 for (;;) { 5177 if (vd->vd_version != VER_DEF_CURRENT) { 5178 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5179 depobj->path, vd->vd_version); 5180 return (-1); 5181 } 5182 if (vna->vna_hash == vd->vd_hash) { 5183 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5184 ((const char *)vd + vd->vd_aux); 5185 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5186 return (0); 5187 } 5188 if (vd->vd_next == 0) 5189 break; 5190 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5191 } 5192 if (vna->vna_flags & VER_FLG_WEAK) 5193 return (0); 5194 _rtld_error("%s: version %s required by %s not found", 5195 depobj->path, vername, refobj->path); 5196 return (-1); 5197 } 5198 5199 static int 5200 rtld_verify_object_versions(Obj_Entry *obj) 5201 { 5202 const Elf_Verneed *vn; 5203 const Elf_Verdef *vd; 5204 const Elf_Verdaux *vda; 5205 const Elf_Vernaux *vna; 5206 const Obj_Entry *depobj; 5207 int maxvernum, vernum; 5208 5209 if (obj->ver_checked) 5210 return (0); 5211 obj->ver_checked = true; 5212 5213 maxvernum = 0; 5214 /* 5215 * Walk over defined and required version records and figure out 5216 * max index used by any of them. Do very basic sanity checking 5217 * while there. 5218 */ 5219 vn = obj->verneed; 5220 while (vn != NULL) { 5221 if (vn->vn_version != VER_NEED_CURRENT) { 5222 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5223 obj->path, vn->vn_version); 5224 return (-1); 5225 } 5226 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5227 for (;;) { 5228 vernum = VER_NEED_IDX(vna->vna_other); 5229 if (vernum > maxvernum) 5230 maxvernum = vernum; 5231 if (vna->vna_next == 0) 5232 break; 5233 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5234 } 5235 if (vn->vn_next == 0) 5236 break; 5237 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5238 } 5239 5240 vd = obj->verdef; 5241 while (vd != NULL) { 5242 if (vd->vd_version != VER_DEF_CURRENT) { 5243 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5244 obj->path, vd->vd_version); 5245 return (-1); 5246 } 5247 vernum = VER_DEF_IDX(vd->vd_ndx); 5248 if (vernum > maxvernum) 5249 maxvernum = vernum; 5250 if (vd->vd_next == 0) 5251 break; 5252 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5253 } 5254 5255 if (maxvernum == 0) 5256 return (0); 5257 5258 /* 5259 * Store version information in array indexable by version index. 5260 * Verify that object version requirements are satisfied along the 5261 * way. 5262 */ 5263 obj->vernum = maxvernum + 1; 5264 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5265 5266 vd = obj->verdef; 5267 while (vd != NULL) { 5268 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5269 vernum = VER_DEF_IDX(vd->vd_ndx); 5270 assert(vernum <= maxvernum); 5271 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5272 obj->vertab[vernum].hash = vd->vd_hash; 5273 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5274 obj->vertab[vernum].file = NULL; 5275 obj->vertab[vernum].flags = 0; 5276 } 5277 if (vd->vd_next == 0) 5278 break; 5279 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5280 } 5281 5282 vn = obj->verneed; 5283 while (vn != NULL) { 5284 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5285 if (depobj == NULL) 5286 return (-1); 5287 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5288 for (;;) { 5289 if (check_object_provided_version(obj, depobj, vna)) 5290 return (-1); 5291 vernum = VER_NEED_IDX(vna->vna_other); 5292 assert(vernum <= maxvernum); 5293 obj->vertab[vernum].hash = vna->vna_hash; 5294 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5295 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5296 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5297 VER_INFO_HIDDEN : 0; 5298 if (vna->vna_next == 0) 5299 break; 5300 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5301 } 5302 if (vn->vn_next == 0) 5303 break; 5304 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5305 } 5306 return 0; 5307 } 5308 5309 static int 5310 rtld_verify_versions(const Objlist *objlist) 5311 { 5312 Objlist_Entry *entry; 5313 int rc; 5314 5315 rc = 0; 5316 STAILQ_FOREACH(entry, objlist, link) { 5317 /* 5318 * Skip dummy objects or objects that have their version requirements 5319 * already checked. 5320 */ 5321 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5322 continue; 5323 if (rtld_verify_object_versions(entry->obj) == -1) { 5324 rc = -1; 5325 if (ld_tracing == NULL) 5326 break; 5327 } 5328 } 5329 if (rc == 0 || ld_tracing != NULL) 5330 rc = rtld_verify_object_versions(&obj_rtld); 5331 return rc; 5332 } 5333 5334 const Ver_Entry * 5335 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5336 { 5337 Elf_Versym vernum; 5338 5339 if (obj->vertab) { 5340 vernum = VER_NDX(obj->versyms[symnum]); 5341 if (vernum >= obj->vernum) { 5342 _rtld_error("%s: symbol %s has wrong verneed value %d", 5343 obj->path, obj->strtab + symnum, vernum); 5344 } else if (obj->vertab[vernum].hash != 0) { 5345 return &obj->vertab[vernum]; 5346 } 5347 } 5348 return NULL; 5349 } 5350 5351 int 5352 _rtld_get_stack_prot(void) 5353 { 5354 5355 return (stack_prot); 5356 } 5357 5358 int 5359 _rtld_is_dlopened(void *arg) 5360 { 5361 Obj_Entry *obj; 5362 RtldLockState lockstate; 5363 int res; 5364 5365 rlock_acquire(rtld_bind_lock, &lockstate); 5366 obj = dlcheck(arg); 5367 if (obj == NULL) 5368 obj = obj_from_addr(arg); 5369 if (obj == NULL) { 5370 _rtld_error("No shared object contains address"); 5371 lock_release(rtld_bind_lock, &lockstate); 5372 return (-1); 5373 } 5374 res = obj->dlopened ? 1 : 0; 5375 lock_release(rtld_bind_lock, &lockstate); 5376 return (res); 5377 } 5378 5379 static int 5380 obj_remap_relro(Obj_Entry *obj, int prot) 5381 { 5382 5383 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5384 prot) == -1) { 5385 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5386 obj->path, prot, rtld_strerror(errno)); 5387 return (-1); 5388 } 5389 return (0); 5390 } 5391 5392 static int 5393 obj_disable_relro(Obj_Entry *obj) 5394 { 5395 5396 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5397 } 5398 5399 static int 5400 obj_enforce_relro(Obj_Entry *obj) 5401 { 5402 5403 return (obj_remap_relro(obj, PROT_READ)); 5404 } 5405 5406 static void 5407 map_stacks_exec(RtldLockState *lockstate) 5408 { 5409 void (*thr_map_stacks_exec)(void); 5410 5411 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5412 return; 5413 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5414 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5415 if (thr_map_stacks_exec != NULL) { 5416 stack_prot |= PROT_EXEC; 5417 thr_map_stacks_exec(); 5418 } 5419 } 5420 5421 static void 5422 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5423 { 5424 Objlist_Entry *elm; 5425 Obj_Entry *obj; 5426 void (*distrib)(size_t, void *, size_t, size_t); 5427 5428 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5429 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5430 if (distrib == NULL) 5431 return; 5432 STAILQ_FOREACH(elm, list, link) { 5433 obj = elm->obj; 5434 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5435 continue; 5436 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5437 obj->tlssize); 5438 obj->static_tls_copied = true; 5439 } 5440 } 5441 5442 void 5443 symlook_init(SymLook *dst, const char *name) 5444 { 5445 5446 bzero(dst, sizeof(*dst)); 5447 dst->name = name; 5448 dst->hash = elf_hash(name); 5449 dst->hash_gnu = gnu_hash(name); 5450 } 5451 5452 static void 5453 symlook_init_from_req(SymLook *dst, const SymLook *src) 5454 { 5455 5456 dst->name = src->name; 5457 dst->hash = src->hash; 5458 dst->hash_gnu = src->hash_gnu; 5459 dst->ventry = src->ventry; 5460 dst->flags = src->flags; 5461 dst->defobj_out = NULL; 5462 dst->sym_out = NULL; 5463 dst->lockstate = src->lockstate; 5464 } 5465 5466 static int 5467 open_binary_fd(const char *argv0, bool search_in_path) 5468 { 5469 char *pathenv, *pe, binpath[PATH_MAX]; 5470 int fd; 5471 5472 if (search_in_path && strchr(argv0, '/') == NULL) { 5473 pathenv = getenv("PATH"); 5474 if (pathenv == NULL) { 5475 _rtld_error("-p and no PATH environment variable"); 5476 rtld_die(); 5477 } 5478 pathenv = strdup(pathenv); 5479 if (pathenv == NULL) { 5480 _rtld_error("Cannot allocate memory"); 5481 rtld_die(); 5482 } 5483 fd = -1; 5484 errno = ENOENT; 5485 while ((pe = strsep(&pathenv, ":")) != NULL) { 5486 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5487 sizeof(binpath)) 5488 continue; 5489 if (binpath[0] != '\0' && 5490 strlcat(binpath, "/", sizeof(binpath)) >= 5491 sizeof(binpath)) 5492 continue; 5493 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5494 sizeof(binpath)) 5495 continue; 5496 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5497 if (fd != -1 || errno != ENOENT) 5498 break; 5499 } 5500 free(pathenv); 5501 } else { 5502 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5503 } 5504 5505 if (fd == -1) { 5506 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5507 rtld_die(); 5508 } 5509 return (fd); 5510 } 5511 5512 /* 5513 * Parse a set of command-line arguments. 5514 */ 5515 static int 5516 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5517 { 5518 const char *arg; 5519 int fd, i, j, arglen; 5520 char opt; 5521 5522 dbg("Parsing command-line arguments"); 5523 *use_pathp = false; 5524 *fdp = -1; 5525 5526 for (i = 1; i < argc; i++ ) { 5527 arg = argv[i]; 5528 dbg("argv[%d]: '%s'", i, arg); 5529 5530 /* 5531 * rtld arguments end with an explicit "--" or with the first 5532 * non-prefixed argument. 5533 */ 5534 if (strcmp(arg, "--") == 0) { 5535 i++; 5536 break; 5537 } 5538 if (arg[0] != '-') 5539 break; 5540 5541 /* 5542 * All other arguments are single-character options that can 5543 * be combined, so we need to search through `arg` for them. 5544 */ 5545 arglen = strlen(arg); 5546 for (j = 1; j < arglen; j++) { 5547 opt = arg[j]; 5548 if (opt == 'h') { 5549 print_usage(argv[0]); 5550 _exit(0); 5551 } else if (opt == 'f') { 5552 /* 5553 * -f XX can be used to specify a descriptor for the 5554 * binary named at the command line (i.e., the later 5555 * argument will specify the process name but the 5556 * descriptor is what will actually be executed) 5557 */ 5558 if (j != arglen - 1) { 5559 /* -f must be the last option in, e.g., -abcf */ 5560 _rtld_error("Invalid options: %s", arg); 5561 rtld_die(); 5562 } 5563 i++; 5564 fd = parse_integer(argv[i]); 5565 if (fd == -1) { 5566 _rtld_error("Invalid file descriptor: '%s'", 5567 argv[i]); 5568 rtld_die(); 5569 } 5570 *fdp = fd; 5571 break; 5572 } else if (opt == 'p') { 5573 *use_pathp = true; 5574 } else { 5575 _rtld_error("Invalid argument: '%s'", arg); 5576 print_usage(argv[0]); 5577 rtld_die(); 5578 } 5579 } 5580 } 5581 5582 return (i); 5583 } 5584 5585 /* 5586 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5587 */ 5588 static int 5589 parse_integer(const char *str) 5590 { 5591 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5592 const char *orig; 5593 int n; 5594 char c; 5595 5596 orig = str; 5597 n = 0; 5598 for (c = *str; c != '\0'; c = *++str) { 5599 if (c < '0' || c > '9') 5600 return (-1); 5601 5602 n *= RADIX; 5603 n += c - '0'; 5604 } 5605 5606 /* Make sure we actually parsed something. */ 5607 if (str == orig) 5608 return (-1); 5609 return (n); 5610 } 5611 5612 static void 5613 print_usage(const char *argv0) 5614 { 5615 5616 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5617 "\n" 5618 "Options:\n" 5619 " -h Display this help message\n" 5620 " -p Search in PATH for named binary\n" 5621 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5622 " -- End of RTLD options\n" 5623 " <binary> Name of process to execute\n" 5624 " <args> Arguments to the executed process\n", argv0); 5625 } 5626 5627 /* 5628 * Overrides for libc_pic-provided functions. 5629 */ 5630 5631 int 5632 __getosreldate(void) 5633 { 5634 size_t len; 5635 int oid[2]; 5636 int error, osrel; 5637 5638 if (osreldate != 0) 5639 return (osreldate); 5640 5641 oid[0] = CTL_KERN; 5642 oid[1] = KERN_OSRELDATE; 5643 osrel = 0; 5644 len = sizeof(osrel); 5645 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5646 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5647 osreldate = osrel; 5648 return (osreldate); 5649 } 5650 5651 void 5652 exit(int status) 5653 { 5654 5655 _exit(status); 5656 } 5657 5658 void (*__cleanup)(void); 5659 int __isthreaded = 0; 5660 int _thread_autoinit_dummy_decl = 1; 5661 5662 /* 5663 * No unresolved symbols for rtld. 5664 */ 5665 void 5666 __pthread_cxa_finalize(struct dl_phdr_info *a __unused) 5667 { 5668 } 5669 5670 const char * 5671 rtld_strerror(int errnum) 5672 { 5673 5674 if (errnum < 0 || errnum >= sys_nerr) 5675 return ("Unknown error"); 5676 return (sys_errlist[errnum]); 5677 } 5678 5679 /* 5680 * No ifunc relocations. 5681 */ 5682 void * 5683 memset(void *dest, int c, size_t len) 5684 { 5685 size_t i; 5686 5687 for (i = 0; i < len; i++) 5688 ((char *)dest)[i] = c; 5689 return (dest); 5690 } 5691 5692 void 5693 bzero(void *dest, size_t len) 5694 { 5695 size_t i; 5696 5697 for (i = 0; i < len; i++) 5698 ((char *)dest)[i] = 0; 5699 } 5700 5701 /* malloc */ 5702 void * 5703 malloc(size_t nbytes) 5704 { 5705 5706 return (__crt_malloc(nbytes)); 5707 } 5708 5709 void * 5710 calloc(size_t num, size_t size) 5711 { 5712 5713 return (__crt_calloc(num, size)); 5714 } 5715 5716 void 5717 free(void *cp) 5718 { 5719 5720 __crt_free(cp); 5721 } 5722 5723 void * 5724 realloc(void *cp, size_t nbytes) 5725 { 5726 5727 return (__crt_realloc(cp, nbytes)); 5728 } 5729