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