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 bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool 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 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 140 static int parse_integer(const char *); 141 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 142 static void print_usage(const char *argv0); 143 static void release_object(Obj_Entry *); 144 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 145 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 146 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 147 int flags, RtldLockState *lockstate); 148 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 149 RtldLockState *); 150 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 151 static int rtld_dirname(const char *, char *); 152 static int rtld_dirname_abs(const char *, char *); 153 static void *rtld_dlopen(const char *name, int fd, int mode); 154 static void rtld_exit(void); 155 static void rtld_nop_exit(void); 156 static char *search_library_path(const char *, const char *, const char *, 157 int *); 158 static char *search_library_pathfds(const char *, const char *, int *); 159 static const void **get_program_var_addr(const char *, RtldLockState *); 160 static void set_program_var(const char *, const void *); 161 static int symlook_default(SymLook *, const Obj_Entry *refobj); 162 static int symlook_global(SymLook *, DoneList *); 163 static void symlook_init_from_req(SymLook *, const SymLook *); 164 static int symlook_list(SymLook *, const Objlist *, DoneList *); 165 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 166 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 167 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 168 static void trace_loaded_objects(Obj_Entry *); 169 static void unlink_object(Obj_Entry *); 170 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 171 static void unref_dag(Obj_Entry *); 172 static void ref_dag(Obj_Entry *); 173 static char *origin_subst_one(Obj_Entry *, char *, const char *, 174 const char *, bool); 175 static char *origin_subst(Obj_Entry *, const char *); 176 static bool obj_resolve_origin(Obj_Entry *obj); 177 static void preinit_main(void); 178 static int rtld_verify_versions(const Objlist *); 179 static int rtld_verify_object_versions(Obj_Entry *); 180 static void object_add_name(Obj_Entry *, const char *); 181 static int object_match_name(const Obj_Entry *, const char *); 182 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 183 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 184 struct dl_phdr_info *phdr_info); 185 static uint32_t gnu_hash(const char *); 186 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 187 const unsigned long); 188 189 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 190 void _r_debug_postinit(struct link_map *) __noinline __exported; 191 192 int __sys_openat(int, const char *, int, ...); 193 194 /* 195 * Data declarations. 196 */ 197 static char *error_message; /* Message for dlerror(), or NULL */ 198 struct r_debug r_debug __exported; /* for GDB; */ 199 static bool libmap_disable; /* Disable libmap */ 200 static bool ld_loadfltr; /* Immediate filters processing */ 201 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 202 static bool trust; /* False for setuid and setgid programs */ 203 static bool dangerous_ld_env; /* True if environment variables have been 204 used to affect the libraries loaded */ 205 bool ld_bind_not; /* Disable PLT update */ 206 static char *ld_bind_now; /* Environment variable for immediate binding */ 207 static char *ld_debug; /* Environment variable for debugging */ 208 static char *ld_library_path; /* Environment variable for search path */ 209 static char *ld_library_dirs; /* Environment variable for library descriptors */ 210 static char *ld_preload; /* Environment variable for libraries to 211 load first */ 212 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 213 static const char *ld_tracing; /* Called from ldd to print libs */ 214 static char *ld_utrace; /* Use utrace() to log events. */ 215 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 216 static Obj_Entry *obj_main; /* The main program shared object */ 217 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 218 static unsigned int obj_count; /* Number of objects in obj_list */ 219 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 220 221 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 222 STAILQ_HEAD_INITIALIZER(list_global); 223 static Objlist list_main = /* Objects loaded at program startup */ 224 STAILQ_HEAD_INITIALIZER(list_main); 225 static Objlist list_fini = /* Objects needing fini() calls */ 226 STAILQ_HEAD_INITIALIZER(list_fini); 227 228 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 229 230 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 231 232 extern Elf_Dyn _DYNAMIC; 233 #pragma weak _DYNAMIC 234 235 int dlclose(void *) __exported; 236 char *dlerror(void) __exported; 237 void *dlopen(const char *, int) __exported; 238 void *fdlopen(int, int) __exported; 239 void *dlsym(void *, const char *) __exported; 240 dlfunc_t dlfunc(void *, const char *) __exported; 241 void *dlvsym(void *, const char *, const char *) __exported; 242 int dladdr(const void *, Dl_info *) __exported; 243 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 244 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 245 int dlinfo(void *, int , void *) __exported; 246 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 247 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 248 int _rtld_get_stack_prot(void) __exported; 249 int _rtld_is_dlopened(void *) __exported; 250 void _rtld_error(const char *, ...) __exported; 251 252 /* Only here to fix -Wmissing-prototypes warnings */ 253 int __getosreldate(void); 254 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 255 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 256 257 258 int npagesizes; 259 static int osreldate; 260 size_t *pagesizes; 261 262 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 263 static int max_stack_flags; 264 265 /* 266 * Global declarations normally provided by crt1. The dynamic linker is 267 * not built with crt1, so we have to provide them ourselves. 268 */ 269 char *__progname; 270 char **environ; 271 272 /* 273 * Used to pass argc, argv to init functions. 274 */ 275 int main_argc; 276 char **main_argv; 277 278 /* 279 * Globals to control TLS allocation. 280 */ 281 size_t tls_last_offset; /* Static TLS offset of last module */ 282 size_t tls_last_size; /* Static TLS size of last module */ 283 size_t tls_static_space; /* Static TLS space allocated */ 284 static size_t tls_static_max_align; 285 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 286 int tls_max_index = 1; /* Largest module index allocated */ 287 288 static bool ld_library_path_rpath = false; 289 bool ld_fast_sigblock = false; 290 291 /* 292 * Globals for path names, and such 293 */ 294 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 295 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 296 const char *ld_path_rtld = _PATH_RTLD; 297 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 298 const char *ld_env_prefix = LD_; 299 300 static void (*rtld_exit_ptr)(void); 301 302 /* 303 * Fill in a DoneList with an allocation large enough to hold all of 304 * the currently-loaded objects. Keep this as a macro since it calls 305 * alloca and we want that to occur within the scope of the caller. 306 */ 307 #define donelist_init(dlp) \ 308 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 309 assert((dlp)->objs != NULL), \ 310 (dlp)->num_alloc = obj_count, \ 311 (dlp)->num_used = 0) 312 313 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 314 if (ld_utrace != NULL) \ 315 ld_utrace_log(e, h, mb, ms, r, n); \ 316 } while (0) 317 318 static void 319 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 320 int refcnt, const char *name) 321 { 322 struct utrace_rtld ut; 323 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 324 325 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 326 ut.event = event; 327 ut.handle = handle; 328 ut.mapbase = mapbase; 329 ut.mapsize = mapsize; 330 ut.refcnt = refcnt; 331 bzero(ut.name, sizeof(ut.name)); 332 if (name) 333 strlcpy(ut.name, name, sizeof(ut.name)); 334 utrace(&ut, sizeof(ut)); 335 } 336 337 #ifdef RTLD_VARIANT_ENV_NAMES 338 /* 339 * construct the env variable based on the type of binary that's 340 * running. 341 */ 342 static inline const char * 343 _LD(const char *var) 344 { 345 static char buffer[128]; 346 347 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 348 strlcat(buffer, var, sizeof(buffer)); 349 return (buffer); 350 } 351 #else 352 #define _LD(x) LD_ x 353 #endif 354 355 /* 356 * Main entry point for dynamic linking. The first argument is the 357 * stack pointer. The stack is expected to be laid out as described 358 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 359 * Specifically, the stack pointer points to a word containing 360 * ARGC. Following that in the stack is a null-terminated sequence 361 * of pointers to argument strings. Then comes a null-terminated 362 * sequence of pointers to environment strings. Finally, there is a 363 * sequence of "auxiliary vector" entries. 364 * 365 * The second argument points to a place to store the dynamic linker's 366 * exit procedure pointer and the third to a place to store the main 367 * program's object. 368 * 369 * The return value is the main program's entry point. 370 */ 371 func_ptr_type 372 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 373 { 374 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 375 Objlist_Entry *entry; 376 Obj_Entry *last_interposer, *obj, *preload_tail; 377 const Elf_Phdr *phdr; 378 Objlist initlist; 379 RtldLockState lockstate; 380 struct stat st; 381 Elf_Addr *argcp; 382 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 383 const char *argv0, *binpath; 384 caddr_t imgentry; 385 char buf[MAXPATHLEN]; 386 int argc, fd, i, phnum, rtld_argc; 387 #ifdef __powerpc__ 388 int old_auxv_format = 1; 389 #endif 390 bool dir_enable, explicit_fd, search_in_path; 391 392 /* 393 * On entry, the dynamic linker itself has not been relocated yet. 394 * Be very careful not to reference any global data until after 395 * init_rtld has returned. It is OK to reference file-scope statics 396 * and string constants, and to call static and global functions. 397 */ 398 399 /* Find the auxiliary vector on the stack. */ 400 argcp = sp; 401 argc = *sp++; 402 argv = (char **) sp; 403 sp += argc + 1; /* Skip over arguments and NULL terminator */ 404 env = (char **) sp; 405 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 406 ; 407 aux = (Elf_Auxinfo *) sp; 408 409 /* Digest the auxiliary vector. */ 410 for (i = 0; i < AT_COUNT; i++) 411 aux_info[i] = NULL; 412 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 413 if (auxp->a_type < AT_COUNT) 414 aux_info[auxp->a_type] = auxp; 415 #ifdef __powerpc__ 416 if (auxp->a_type == 23) /* AT_STACKPROT */ 417 old_auxv_format = 0; 418 #endif 419 } 420 421 #ifdef __powerpc__ 422 if (old_auxv_format) { 423 /* Remap from old-style auxv numbers. */ 424 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 425 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 426 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 427 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 428 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 429 aux_info[13] = NULL; /* AT_GID */ 430 431 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 432 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 433 aux_info[16] = aux_info[14]; /* AT_CANARY */ 434 aux_info[14] = NULL; /* AT_EGID */ 435 } 436 #endif 437 438 /* Initialize and relocate ourselves. */ 439 assert(aux_info[AT_BASE] != NULL); 440 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 441 442 __progname = obj_rtld.path; 443 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 444 environ = env; 445 main_argc = argc; 446 main_argv = argv; 447 448 if (aux_info[AT_BSDFLAGS] != NULL && 449 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 450 ld_fast_sigblock = true; 451 452 trust = !issetugid(); 453 454 md_abi_variant_hook(aux_info); 455 456 fd = -1; 457 if (aux_info[AT_EXECFD] != NULL) { 458 fd = aux_info[AT_EXECFD]->a_un.a_val; 459 } else { 460 assert(aux_info[AT_PHDR] != NULL); 461 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 462 if (phdr == obj_rtld.phdr) { 463 if (!trust) { 464 _rtld_error("Tainted process refusing to run binary %s", 465 argv0); 466 rtld_die(); 467 } 468 dbg("opening main program in direct exec mode"); 469 if (argc >= 2) { 470 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 471 argv0 = argv[rtld_argc]; 472 explicit_fd = (fd != -1); 473 binpath = NULL; 474 if (!explicit_fd) 475 fd = open_binary_fd(argv0, search_in_path, &binpath); 476 if (fstat(fd, &st) == -1) { 477 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 478 explicit_fd ? "user-provided descriptor" : argv0, 479 rtld_strerror(errno)); 480 rtld_die(); 481 } 482 483 /* 484 * Rough emulation of the permission checks done by 485 * execve(2), only Unix DACs are checked, ACLs are 486 * ignored. Preserve the semantic of disabling owner 487 * to execute if owner x bit is cleared, even if 488 * others x bit is enabled. 489 * mmap(2) does not allow to mmap with PROT_EXEC if 490 * binary' file comes from noexec mount. We cannot 491 * set a text reference on the binary. 492 */ 493 dir_enable = false; 494 if (st.st_uid == geteuid()) { 495 if ((st.st_mode & S_IXUSR) != 0) 496 dir_enable = true; 497 } else if (st.st_gid == getegid()) { 498 if ((st.st_mode & S_IXGRP) != 0) 499 dir_enable = true; 500 } else if ((st.st_mode & S_IXOTH) != 0) { 501 dir_enable = true; 502 } 503 if (!dir_enable) { 504 _rtld_error("No execute permission for binary %s", 505 argv0); 506 rtld_die(); 507 } 508 509 /* 510 * For direct exec mode, argv[0] is the interpreter 511 * name, we must remove it and shift arguments left 512 * before invoking binary main. Since stack layout 513 * places environment pointers and aux vectors right 514 * after the terminating NULL, we must shift 515 * environment and aux as well. 516 */ 517 main_argc = argc - rtld_argc; 518 for (i = 0; i <= main_argc; i++) 519 argv[i] = argv[i + rtld_argc]; 520 *argcp -= rtld_argc; 521 environ = env = envp = argv + main_argc + 1; 522 dbg("move env from %p to %p", envp + rtld_argc, envp); 523 do { 524 *envp = *(envp + rtld_argc); 525 } while (*envp++ != NULL); 526 aux = auxp = (Elf_Auxinfo *)envp; 527 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 528 dbg("move aux from %p to %p", auxpf, aux); 529 /* XXXKIB insert place for AT_EXECPATH if not present */ 530 for (;; auxp++, auxpf++) { 531 *auxp = *auxpf; 532 if (auxp->a_type == AT_NULL) 533 break; 534 } 535 /* Since the auxiliary vector has moved, redigest it. */ 536 for (i = 0; i < AT_COUNT; i++) 537 aux_info[i] = NULL; 538 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 539 if (auxp->a_type < AT_COUNT) 540 aux_info[auxp->a_type] = auxp; 541 } 542 543 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 544 if (binpath == NULL) { 545 aux_info[AT_EXECPATH] = NULL; 546 } else { 547 if (aux_info[AT_EXECPATH] == NULL) { 548 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 549 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 550 } 551 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 552 binpath); 553 } 554 } else { 555 _rtld_error("No binary"); 556 rtld_die(); 557 } 558 } 559 } 560 561 ld_bind_now = getenv(_LD("BIND_NOW")); 562 563 /* 564 * If the process is tainted, then we un-set the dangerous environment 565 * variables. The process will be marked as tainted until setuid(2) 566 * is called. If any child process calls setuid(2) we do not want any 567 * future processes to honor the potentially un-safe variables. 568 */ 569 if (!trust) { 570 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 571 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 572 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 573 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 574 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 575 _rtld_error("environment corrupt; aborting"); 576 rtld_die(); 577 } 578 } 579 ld_debug = getenv(_LD("DEBUG")); 580 if (ld_bind_now == NULL) 581 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 582 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 583 libmap_override = getenv(_LD("LIBMAP")); 584 ld_library_path = getenv(_LD("LIBRARY_PATH")); 585 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 586 ld_preload = getenv(_LD("PRELOAD")); 587 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 588 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 589 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 590 if (library_path_rpath != NULL) { 591 if (library_path_rpath[0] == 'y' || 592 library_path_rpath[0] == 'Y' || 593 library_path_rpath[0] == '1') 594 ld_library_path_rpath = true; 595 else 596 ld_library_path_rpath = false; 597 } 598 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 599 (ld_library_path != NULL) || (ld_preload != NULL) || 600 (ld_elf_hints_path != NULL) || ld_loadfltr; 601 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 602 ld_utrace = getenv(_LD("UTRACE")); 603 604 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 605 ld_elf_hints_path = ld_elf_hints_default; 606 607 if (ld_debug != NULL && *ld_debug != '\0') 608 debug = 1; 609 dbg("%s is initialized, base address = %p", __progname, 610 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 611 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 612 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 613 614 dbg("initializing thread locks"); 615 lockdflt_init(); 616 617 /* 618 * Load the main program, or process its program header if it is 619 * already loaded. 620 */ 621 if (fd != -1) { /* Load the main program. */ 622 dbg("loading main program"); 623 obj_main = map_object(fd, argv0, NULL); 624 close(fd); 625 if (obj_main == NULL) 626 rtld_die(); 627 max_stack_flags = obj_main->stack_flags; 628 } else { /* Main program already loaded. */ 629 dbg("processing main program's program header"); 630 assert(aux_info[AT_PHDR] != NULL); 631 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 632 assert(aux_info[AT_PHNUM] != NULL); 633 phnum = aux_info[AT_PHNUM]->a_un.a_val; 634 assert(aux_info[AT_PHENT] != NULL); 635 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 636 assert(aux_info[AT_ENTRY] != NULL); 637 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 638 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 639 rtld_die(); 640 } 641 642 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 643 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 644 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 645 if (kexecpath[0] == '/') 646 obj_main->path = kexecpath; 647 else if (getcwd(buf, sizeof(buf)) == NULL || 648 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 649 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 650 obj_main->path = xstrdup(argv0); 651 else 652 obj_main->path = xstrdup(buf); 653 } else { 654 dbg("No AT_EXECPATH or direct exec"); 655 obj_main->path = xstrdup(argv0); 656 } 657 dbg("obj_main path %s", obj_main->path); 658 obj_main->mainprog = true; 659 660 if (aux_info[AT_STACKPROT] != NULL && 661 aux_info[AT_STACKPROT]->a_un.a_val != 0) 662 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 663 664 #ifndef COMPAT_32BIT 665 /* 666 * Get the actual dynamic linker pathname from the executable if 667 * possible. (It should always be possible.) That ensures that 668 * gdb will find the right dynamic linker even if a non-standard 669 * one is being used. 670 */ 671 if (obj_main->interp != NULL && 672 strcmp(obj_main->interp, obj_rtld.path) != 0) { 673 free(obj_rtld.path); 674 obj_rtld.path = xstrdup(obj_main->interp); 675 __progname = obj_rtld.path; 676 } 677 #endif 678 679 if (!digest_dynamic(obj_main, 0)) 680 rtld_die(); 681 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 682 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 683 obj_main->dynsymcount); 684 685 linkmap_add(obj_main); 686 linkmap_add(&obj_rtld); 687 688 /* Link the main program into the list of objects. */ 689 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 690 obj_count++; 691 obj_loads++; 692 693 /* Initialize a fake symbol for resolving undefined weak references. */ 694 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 695 sym_zero.st_shndx = SHN_UNDEF; 696 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 697 698 if (!libmap_disable) 699 libmap_disable = (bool)lm_init(libmap_override); 700 701 dbg("loading LD_PRELOAD libraries"); 702 if (load_preload_objects() == -1) 703 rtld_die(); 704 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 705 706 dbg("loading needed objects"); 707 if (load_needed_objects(obj_main, 0) == -1) 708 rtld_die(); 709 710 /* Make a list of all objects loaded at startup. */ 711 last_interposer = obj_main; 712 TAILQ_FOREACH(obj, &obj_list, next) { 713 if (obj->marker) 714 continue; 715 if (obj->z_interpose && obj != obj_main) { 716 objlist_put_after(&list_main, last_interposer, obj); 717 last_interposer = obj; 718 } else { 719 objlist_push_tail(&list_main, obj); 720 } 721 obj->refcount++; 722 } 723 724 dbg("checking for required versions"); 725 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 726 rtld_die(); 727 728 if (ld_tracing) { /* We're done */ 729 trace_loaded_objects(obj_main); 730 exit(0); 731 } 732 733 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 734 dump_relocations(obj_main); 735 exit (0); 736 } 737 738 /* 739 * Processing tls relocations requires having the tls offsets 740 * initialized. Prepare offsets before starting initial 741 * relocation processing. 742 */ 743 dbg("initializing initial thread local storage offsets"); 744 STAILQ_FOREACH(entry, &list_main, link) { 745 /* 746 * Allocate all the initial objects out of the static TLS 747 * block even if they didn't ask for it. 748 */ 749 allocate_tls_offset(entry->obj); 750 } 751 752 if (relocate_objects(obj_main, 753 ld_bind_now != NULL && *ld_bind_now != '\0', 754 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 755 rtld_die(); 756 757 dbg("doing copy relocations"); 758 if (do_copy_relocations(obj_main) == -1) 759 rtld_die(); 760 761 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 762 dump_relocations(obj_main); 763 exit (0); 764 } 765 766 ifunc_init(aux); 767 768 /* 769 * Setup TLS for main thread. This must be done after the 770 * relocations are processed, since tls initialization section 771 * might be the subject for relocations. 772 */ 773 dbg("initializing initial thread local storage"); 774 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 775 776 dbg("initializing key program variables"); 777 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 778 set_program_var("environ", env); 779 set_program_var("__elf_aux_vector", aux); 780 781 /* Make a list of init functions to call. */ 782 objlist_init(&initlist); 783 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 784 preload_tail, &initlist); 785 786 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 787 788 map_stacks_exec(NULL); 789 790 if (!obj_main->crt_no_init) { 791 /* 792 * Make sure we don't call the main program's init and fini 793 * functions for binaries linked with old crt1 which calls 794 * _init itself. 795 */ 796 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 797 obj_main->preinit_array = obj_main->init_array = 798 obj_main->fini_array = (Elf_Addr)NULL; 799 } 800 801 /* 802 * Execute MD initializers required before we call the objects' 803 * init functions. 804 */ 805 pre_init(); 806 807 wlock_acquire(rtld_bind_lock, &lockstate); 808 809 dbg("resolving ifuncs"); 810 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 811 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 812 rtld_die(); 813 814 rtld_exit_ptr = rtld_exit; 815 if (obj_main->crt_no_init) 816 preinit_main(); 817 objlist_call_init(&initlist, &lockstate); 818 _r_debug_postinit(&obj_main->linkmap); 819 objlist_clear(&initlist); 820 dbg("loading filtees"); 821 TAILQ_FOREACH(obj, &obj_list, next) { 822 if (obj->marker) 823 continue; 824 if (ld_loadfltr || obj->z_loadfltr) 825 load_filtees(obj, 0, &lockstate); 826 } 827 828 dbg("enforcing main obj relro"); 829 if (obj_enforce_relro(obj_main) == -1) 830 rtld_die(); 831 832 lock_release(rtld_bind_lock, &lockstate); 833 834 dbg("transferring control to program entry point = %p", obj_main->entry); 835 836 /* Return the exit procedure and the program entry point. */ 837 *exit_proc = rtld_exit_ptr; 838 *objp = obj_main; 839 return (func_ptr_type) obj_main->entry; 840 } 841 842 void * 843 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 844 { 845 void *ptr; 846 Elf_Addr target; 847 848 ptr = (void *)make_function_pointer(def, obj); 849 target = call_ifunc_resolver(ptr); 850 return ((void *)target); 851 } 852 853 /* 854 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 855 * Changes to this function should be applied there as well. 856 */ 857 Elf_Addr 858 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 859 { 860 const Elf_Rel *rel; 861 const Elf_Sym *def; 862 const Obj_Entry *defobj; 863 Elf_Addr *where; 864 Elf_Addr target; 865 RtldLockState lockstate; 866 867 rlock_acquire(rtld_bind_lock, &lockstate); 868 if (sigsetjmp(lockstate.env, 0) != 0) 869 lock_upgrade(rtld_bind_lock, &lockstate); 870 if (obj->pltrel) 871 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 872 else 873 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 874 875 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 876 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 877 NULL, &lockstate); 878 if (def == NULL) 879 rtld_die(); 880 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 881 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 882 else 883 target = (Elf_Addr)(defobj->relocbase + def->st_value); 884 885 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 886 defobj->strtab + def->st_name, basename(obj->path), 887 (void *)target, basename(defobj->path)); 888 889 /* 890 * Write the new contents for the jmpslot. Note that depending on 891 * architecture, the value which we need to return back to the 892 * lazy binding trampoline may or may not be the target 893 * address. The value returned from reloc_jmpslot() is the value 894 * that the trampoline needs. 895 */ 896 target = reloc_jmpslot(where, target, defobj, obj, rel); 897 lock_release(rtld_bind_lock, &lockstate); 898 return target; 899 } 900 901 /* 902 * Error reporting function. Use it like printf. If formats the message 903 * into a buffer, and sets things up so that the next call to dlerror() 904 * will return the message. 905 */ 906 void 907 _rtld_error(const char *fmt, ...) 908 { 909 static char buf[512]; 910 va_list ap; 911 912 va_start(ap, fmt); 913 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 914 error_message = buf; 915 va_end(ap); 916 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 917 } 918 919 /* 920 * Return a dynamically-allocated copy of the current error message, if any. 921 */ 922 static char * 923 errmsg_save(void) 924 { 925 return error_message == NULL ? NULL : xstrdup(error_message); 926 } 927 928 /* 929 * Restore the current error message from a copy which was previously saved 930 * by errmsg_save(). The copy is freed. 931 */ 932 static void 933 errmsg_restore(char *saved_msg) 934 { 935 if (saved_msg == NULL) 936 error_message = NULL; 937 else { 938 _rtld_error("%s", saved_msg); 939 free(saved_msg); 940 } 941 } 942 943 static const char * 944 basename(const char *name) 945 { 946 const char *p = strrchr(name, '/'); 947 return p != NULL ? p + 1 : name; 948 } 949 950 static struct utsname uts; 951 952 static char * 953 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 954 const char *subst, bool may_free) 955 { 956 char *p, *p1, *res, *resp; 957 int subst_len, kw_len, subst_count, old_len, new_len; 958 959 kw_len = strlen(kw); 960 961 /* 962 * First, count the number of the keyword occurrences, to 963 * preallocate the final string. 964 */ 965 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 966 p1 = strstr(p, kw); 967 if (p1 == NULL) 968 break; 969 } 970 971 /* 972 * If the keyword is not found, just return. 973 * 974 * Return non-substituted string if resolution failed. We 975 * cannot do anything more reasonable, the failure mode of the 976 * caller is unresolved library anyway. 977 */ 978 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 979 return (may_free ? real : xstrdup(real)); 980 if (obj != NULL) 981 subst = obj->origin_path; 982 983 /* 984 * There is indeed something to substitute. Calculate the 985 * length of the resulting string, and allocate it. 986 */ 987 subst_len = strlen(subst); 988 old_len = strlen(real); 989 new_len = old_len + (subst_len - kw_len) * subst_count; 990 res = xmalloc(new_len + 1); 991 992 /* 993 * Now, execute the substitution loop. 994 */ 995 for (p = real, resp = res, *resp = '\0';;) { 996 p1 = strstr(p, kw); 997 if (p1 != NULL) { 998 /* Copy the prefix before keyword. */ 999 memcpy(resp, p, p1 - p); 1000 resp += p1 - p; 1001 /* Keyword replacement. */ 1002 memcpy(resp, subst, subst_len); 1003 resp += subst_len; 1004 *resp = '\0'; 1005 p = p1 + kw_len; 1006 } else 1007 break; 1008 } 1009 1010 /* Copy to the end of string and finish. */ 1011 strcat(resp, p); 1012 if (may_free) 1013 free(real); 1014 return (res); 1015 } 1016 1017 static char * 1018 origin_subst(Obj_Entry *obj, const char *real) 1019 { 1020 char *res1, *res2, *res3, *res4; 1021 1022 if (obj == NULL || !trust) 1023 return (xstrdup(real)); 1024 if (uts.sysname[0] == '\0') { 1025 if (uname(&uts) != 0) { 1026 _rtld_error("utsname failed: %d", errno); 1027 return (NULL); 1028 } 1029 } 1030 /* __DECONST is safe here since without may_free real is unchanged */ 1031 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1032 false); 1033 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1034 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1035 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1036 return (res4); 1037 } 1038 1039 void 1040 rtld_die(void) 1041 { 1042 const char *msg = dlerror(); 1043 1044 if (msg == NULL) 1045 msg = "Fatal error"; 1046 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1047 rtld_fdputstr(STDERR_FILENO, msg); 1048 rtld_fdputchar(STDERR_FILENO, '\n'); 1049 _exit(1); 1050 } 1051 1052 /* 1053 * Process a shared object's DYNAMIC section, and save the important 1054 * information in its Obj_Entry structure. 1055 */ 1056 static void 1057 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1058 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1059 { 1060 const Elf_Dyn *dynp; 1061 Needed_Entry **needed_tail = &obj->needed; 1062 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1063 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1064 const Elf_Hashelt *hashtab; 1065 const Elf32_Word *hashval; 1066 Elf32_Word bkt, nmaskwords; 1067 int bloom_size32; 1068 int plttype = DT_REL; 1069 1070 *dyn_rpath = NULL; 1071 *dyn_soname = NULL; 1072 *dyn_runpath = NULL; 1073 1074 obj->bind_now = false; 1075 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1076 switch (dynp->d_tag) { 1077 1078 case DT_REL: 1079 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1080 break; 1081 1082 case DT_RELSZ: 1083 obj->relsize = dynp->d_un.d_val; 1084 break; 1085 1086 case DT_RELENT: 1087 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1088 break; 1089 1090 case DT_JMPREL: 1091 obj->pltrel = (const Elf_Rel *) 1092 (obj->relocbase + dynp->d_un.d_ptr); 1093 break; 1094 1095 case DT_PLTRELSZ: 1096 obj->pltrelsize = dynp->d_un.d_val; 1097 break; 1098 1099 case DT_RELA: 1100 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1101 break; 1102 1103 case DT_RELASZ: 1104 obj->relasize = dynp->d_un.d_val; 1105 break; 1106 1107 case DT_RELAENT: 1108 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1109 break; 1110 1111 case DT_PLTREL: 1112 plttype = dynp->d_un.d_val; 1113 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1114 break; 1115 1116 case DT_SYMTAB: 1117 obj->symtab = (const Elf_Sym *) 1118 (obj->relocbase + dynp->d_un.d_ptr); 1119 break; 1120 1121 case DT_SYMENT: 1122 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1123 break; 1124 1125 case DT_STRTAB: 1126 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1127 break; 1128 1129 case DT_STRSZ: 1130 obj->strsize = dynp->d_un.d_val; 1131 break; 1132 1133 case DT_VERNEED: 1134 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1135 dynp->d_un.d_val); 1136 break; 1137 1138 case DT_VERNEEDNUM: 1139 obj->verneednum = dynp->d_un.d_val; 1140 break; 1141 1142 case DT_VERDEF: 1143 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1144 dynp->d_un.d_val); 1145 break; 1146 1147 case DT_VERDEFNUM: 1148 obj->verdefnum = dynp->d_un.d_val; 1149 break; 1150 1151 case DT_VERSYM: 1152 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1153 dynp->d_un.d_val); 1154 break; 1155 1156 case DT_HASH: 1157 { 1158 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1159 dynp->d_un.d_ptr); 1160 obj->nbuckets = hashtab[0]; 1161 obj->nchains = hashtab[1]; 1162 obj->buckets = hashtab + 2; 1163 obj->chains = obj->buckets + obj->nbuckets; 1164 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1165 obj->buckets != NULL; 1166 } 1167 break; 1168 1169 case DT_GNU_HASH: 1170 { 1171 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1172 dynp->d_un.d_ptr); 1173 obj->nbuckets_gnu = hashtab[0]; 1174 obj->symndx_gnu = hashtab[1]; 1175 nmaskwords = hashtab[2]; 1176 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1177 obj->maskwords_bm_gnu = nmaskwords - 1; 1178 obj->shift2_gnu = hashtab[3]; 1179 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1180 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1181 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1182 obj->symndx_gnu; 1183 /* Number of bitmask words is required to be power of 2 */ 1184 obj->valid_hash_gnu = powerof2(nmaskwords) && 1185 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1186 } 1187 break; 1188 1189 case DT_NEEDED: 1190 if (!obj->rtld) { 1191 Needed_Entry *nep = NEW(Needed_Entry); 1192 nep->name = dynp->d_un.d_val; 1193 nep->obj = NULL; 1194 nep->next = NULL; 1195 1196 *needed_tail = nep; 1197 needed_tail = &nep->next; 1198 } 1199 break; 1200 1201 case DT_FILTER: 1202 if (!obj->rtld) { 1203 Needed_Entry *nep = NEW(Needed_Entry); 1204 nep->name = dynp->d_un.d_val; 1205 nep->obj = NULL; 1206 nep->next = NULL; 1207 1208 *needed_filtees_tail = nep; 1209 needed_filtees_tail = &nep->next; 1210 1211 if (obj->linkmap.l_refname == NULL) 1212 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1213 } 1214 break; 1215 1216 case DT_AUXILIARY: 1217 if (!obj->rtld) { 1218 Needed_Entry *nep = NEW(Needed_Entry); 1219 nep->name = dynp->d_un.d_val; 1220 nep->obj = NULL; 1221 nep->next = NULL; 1222 1223 *needed_aux_filtees_tail = nep; 1224 needed_aux_filtees_tail = &nep->next; 1225 } 1226 break; 1227 1228 case DT_PLTGOT: 1229 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1230 break; 1231 1232 case DT_TEXTREL: 1233 obj->textrel = true; 1234 break; 1235 1236 case DT_SYMBOLIC: 1237 obj->symbolic = true; 1238 break; 1239 1240 case DT_RPATH: 1241 /* 1242 * We have to wait until later to process this, because we 1243 * might not have gotten the address of the string table yet. 1244 */ 1245 *dyn_rpath = dynp; 1246 break; 1247 1248 case DT_SONAME: 1249 *dyn_soname = dynp; 1250 break; 1251 1252 case DT_RUNPATH: 1253 *dyn_runpath = dynp; 1254 break; 1255 1256 case DT_INIT: 1257 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1258 break; 1259 1260 case DT_PREINIT_ARRAY: 1261 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1262 break; 1263 1264 case DT_PREINIT_ARRAYSZ: 1265 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1266 break; 1267 1268 case DT_INIT_ARRAY: 1269 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1270 break; 1271 1272 case DT_INIT_ARRAYSZ: 1273 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1274 break; 1275 1276 case DT_FINI: 1277 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1278 break; 1279 1280 case DT_FINI_ARRAY: 1281 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_FINI_ARRAYSZ: 1285 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1286 break; 1287 1288 /* 1289 * Don't process DT_DEBUG on MIPS as the dynamic section 1290 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1291 */ 1292 1293 #ifndef __mips__ 1294 case DT_DEBUG: 1295 if (!early) 1296 dbg("Filling in DT_DEBUG entry"); 1297 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1298 break; 1299 #endif 1300 1301 case DT_FLAGS: 1302 if (dynp->d_un.d_val & DF_ORIGIN) 1303 obj->z_origin = true; 1304 if (dynp->d_un.d_val & DF_SYMBOLIC) 1305 obj->symbolic = true; 1306 if (dynp->d_un.d_val & DF_TEXTREL) 1307 obj->textrel = true; 1308 if (dynp->d_un.d_val & DF_BIND_NOW) 1309 obj->bind_now = true; 1310 if (dynp->d_un.d_val & DF_STATIC_TLS) 1311 obj->static_tls = true; 1312 break; 1313 #ifdef __mips__ 1314 case DT_MIPS_LOCAL_GOTNO: 1315 obj->local_gotno = dynp->d_un.d_val; 1316 break; 1317 1318 case DT_MIPS_SYMTABNO: 1319 obj->symtabno = dynp->d_un.d_val; 1320 break; 1321 1322 case DT_MIPS_GOTSYM: 1323 obj->gotsym = dynp->d_un.d_val; 1324 break; 1325 1326 case DT_MIPS_RLD_MAP: 1327 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1328 break; 1329 1330 case DT_MIPS_RLD_MAP_REL: 1331 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1332 // section relative to the address of the tag itself. 1333 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1334 (Elf_Addr) &r_debug; 1335 break; 1336 1337 case DT_MIPS_PLTGOT: 1338 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1339 dynp->d_un.d_ptr); 1340 break; 1341 1342 #endif 1343 1344 #ifdef __powerpc__ 1345 #ifdef __powerpc64__ 1346 case DT_PPC64_GLINK: 1347 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1348 break; 1349 #else 1350 case DT_PPC_GOT: 1351 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1352 break; 1353 #endif 1354 #endif 1355 1356 case DT_FLAGS_1: 1357 if (dynp->d_un.d_val & DF_1_NOOPEN) 1358 obj->z_noopen = true; 1359 if (dynp->d_un.d_val & DF_1_ORIGIN) 1360 obj->z_origin = true; 1361 if (dynp->d_un.d_val & DF_1_GLOBAL) 1362 obj->z_global = true; 1363 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1364 obj->bind_now = true; 1365 if (dynp->d_un.d_val & DF_1_NODELETE) 1366 obj->z_nodelete = true; 1367 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1368 obj->z_loadfltr = true; 1369 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1370 obj->z_interpose = true; 1371 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1372 obj->z_nodeflib = true; 1373 break; 1374 1375 default: 1376 if (!early) { 1377 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1378 (long)dynp->d_tag); 1379 } 1380 break; 1381 } 1382 } 1383 1384 obj->traced = false; 1385 1386 if (plttype == DT_RELA) { 1387 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1388 obj->pltrel = NULL; 1389 obj->pltrelasize = obj->pltrelsize; 1390 obj->pltrelsize = 0; 1391 } 1392 1393 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1394 if (obj->valid_hash_sysv) 1395 obj->dynsymcount = obj->nchains; 1396 else if (obj->valid_hash_gnu) { 1397 obj->dynsymcount = 0; 1398 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1399 if (obj->buckets_gnu[bkt] == 0) 1400 continue; 1401 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1402 do 1403 obj->dynsymcount++; 1404 while ((*hashval++ & 1u) == 0); 1405 } 1406 obj->dynsymcount += obj->symndx_gnu; 1407 } 1408 1409 if (obj->linkmap.l_refname != NULL) 1410 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1411 linkmap.l_refname; 1412 } 1413 1414 static bool 1415 obj_resolve_origin(Obj_Entry *obj) 1416 { 1417 1418 if (obj->origin_path != NULL) 1419 return (true); 1420 obj->origin_path = xmalloc(PATH_MAX); 1421 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1422 } 1423 1424 static bool 1425 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1426 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1427 { 1428 1429 if (obj->z_origin && !obj_resolve_origin(obj)) 1430 return (false); 1431 1432 if (dyn_runpath != NULL) { 1433 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1434 obj->runpath = origin_subst(obj, obj->runpath); 1435 } else if (dyn_rpath != NULL) { 1436 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1437 obj->rpath = origin_subst(obj, obj->rpath); 1438 } 1439 if (dyn_soname != NULL) 1440 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1441 return (true); 1442 } 1443 1444 static bool 1445 digest_dynamic(Obj_Entry *obj, int early) 1446 { 1447 const Elf_Dyn *dyn_rpath; 1448 const Elf_Dyn *dyn_soname; 1449 const Elf_Dyn *dyn_runpath; 1450 1451 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1452 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1453 } 1454 1455 /* 1456 * Process a shared object's program header. This is used only for the 1457 * main program, when the kernel has already loaded the main program 1458 * into memory before calling the dynamic linker. It creates and 1459 * returns an Obj_Entry structure. 1460 */ 1461 static Obj_Entry * 1462 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1463 { 1464 Obj_Entry *obj; 1465 const Elf_Phdr *phlimit = phdr + phnum; 1466 const Elf_Phdr *ph; 1467 Elf_Addr note_start, note_end; 1468 int nsegs = 0; 1469 1470 obj = obj_new(); 1471 for (ph = phdr; ph < phlimit; ph++) { 1472 if (ph->p_type != PT_PHDR) 1473 continue; 1474 1475 obj->phdr = phdr; 1476 obj->phsize = ph->p_memsz; 1477 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1478 break; 1479 } 1480 1481 obj->stack_flags = PF_X | PF_R | PF_W; 1482 1483 for (ph = phdr; ph < phlimit; ph++) { 1484 switch (ph->p_type) { 1485 1486 case PT_INTERP: 1487 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1488 break; 1489 1490 case PT_LOAD: 1491 if (nsegs == 0) { /* First load segment */ 1492 obj->vaddrbase = trunc_page(ph->p_vaddr); 1493 obj->mapbase = obj->vaddrbase + obj->relocbase; 1494 } else { /* Last load segment */ 1495 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1496 obj->vaddrbase; 1497 } 1498 nsegs++; 1499 break; 1500 1501 case PT_DYNAMIC: 1502 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1503 break; 1504 1505 case PT_TLS: 1506 obj->tlsindex = 1; 1507 obj->tlssize = ph->p_memsz; 1508 obj->tlsalign = ph->p_align; 1509 obj->tlsinitsize = ph->p_filesz; 1510 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1511 obj->tlspoffset = ph->p_offset; 1512 break; 1513 1514 case PT_GNU_STACK: 1515 obj->stack_flags = ph->p_flags; 1516 break; 1517 1518 case PT_GNU_RELRO: 1519 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1520 obj->relro_size = round_page(ph->p_memsz); 1521 break; 1522 1523 case PT_NOTE: 1524 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1525 note_end = note_start + ph->p_filesz; 1526 digest_notes(obj, note_start, note_end); 1527 break; 1528 } 1529 } 1530 if (nsegs < 1) { 1531 _rtld_error("%s: too few PT_LOAD segments", path); 1532 return NULL; 1533 } 1534 1535 obj->entry = entry; 1536 return obj; 1537 } 1538 1539 void 1540 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1541 { 1542 const Elf_Note *note; 1543 const char *note_name; 1544 uintptr_t p; 1545 1546 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1547 note = (const Elf_Note *)((const char *)(note + 1) + 1548 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1549 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1550 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1551 note->n_descsz != sizeof(int32_t)) 1552 continue; 1553 if (note->n_type != NT_FREEBSD_ABI_TAG && 1554 note->n_type != NT_FREEBSD_FEATURE_CTL && 1555 note->n_type != NT_FREEBSD_NOINIT_TAG) 1556 continue; 1557 note_name = (const char *)(note + 1); 1558 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1559 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1560 continue; 1561 switch (note->n_type) { 1562 case NT_FREEBSD_ABI_TAG: 1563 /* FreeBSD osrel note */ 1564 p = (uintptr_t)(note + 1); 1565 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1566 obj->osrel = *(const int32_t *)(p); 1567 dbg("note osrel %d", obj->osrel); 1568 break; 1569 case NT_FREEBSD_FEATURE_CTL: 1570 /* FreeBSD ABI feature control note */ 1571 p = (uintptr_t)(note + 1); 1572 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1573 obj->fctl0 = *(const uint32_t *)(p); 1574 dbg("note fctl0 %#x", obj->fctl0); 1575 break; 1576 case NT_FREEBSD_NOINIT_TAG: 1577 /* FreeBSD 'crt does not call init' note */ 1578 obj->crt_no_init = true; 1579 dbg("note crt_no_init"); 1580 break; 1581 } 1582 } 1583 } 1584 1585 static Obj_Entry * 1586 dlcheck(void *handle) 1587 { 1588 Obj_Entry *obj; 1589 1590 TAILQ_FOREACH(obj, &obj_list, next) { 1591 if (obj == (Obj_Entry *) handle) 1592 break; 1593 } 1594 1595 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1596 _rtld_error("Invalid shared object handle %p", handle); 1597 return NULL; 1598 } 1599 return obj; 1600 } 1601 1602 /* 1603 * If the given object is already in the donelist, return true. Otherwise 1604 * add the object to the list and return false. 1605 */ 1606 static bool 1607 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1608 { 1609 unsigned int i; 1610 1611 for (i = 0; i < dlp->num_used; i++) 1612 if (dlp->objs[i] == obj) 1613 return true; 1614 /* 1615 * Our donelist allocation should always be sufficient. But if 1616 * our threads locking isn't working properly, more shared objects 1617 * could have been loaded since we allocated the list. That should 1618 * never happen, but we'll handle it properly just in case it does. 1619 */ 1620 if (dlp->num_used < dlp->num_alloc) 1621 dlp->objs[dlp->num_used++] = obj; 1622 return false; 1623 } 1624 1625 /* 1626 * Hash function for symbol table lookup. Don't even think about changing 1627 * this. It is specified by the System V ABI. 1628 */ 1629 unsigned long 1630 elf_hash(const char *name) 1631 { 1632 const unsigned char *p = (const unsigned char *) name; 1633 unsigned long h = 0; 1634 unsigned long g; 1635 1636 while (*p != '\0') { 1637 h = (h << 4) + *p++; 1638 if ((g = h & 0xf0000000) != 0) 1639 h ^= g >> 24; 1640 h &= ~g; 1641 } 1642 return h; 1643 } 1644 1645 /* 1646 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1647 * unsigned in case it's implemented with a wider type. 1648 */ 1649 static uint32_t 1650 gnu_hash(const char *s) 1651 { 1652 uint32_t h; 1653 unsigned char c; 1654 1655 h = 5381; 1656 for (c = *s; c != '\0'; c = *++s) 1657 h = h * 33 + c; 1658 return (h & 0xffffffff); 1659 } 1660 1661 1662 /* 1663 * Find the library with the given name, and return its full pathname. 1664 * The returned string is dynamically allocated. Generates an error 1665 * message and returns NULL if the library cannot be found. 1666 * 1667 * If the second argument is non-NULL, then it refers to an already- 1668 * loaded shared object, whose library search path will be searched. 1669 * 1670 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1671 * descriptor (which is close-on-exec) will be passed out via the third 1672 * argument. 1673 * 1674 * The search order is: 1675 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1676 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1677 * LD_LIBRARY_PATH 1678 * DT_RUNPATH in the referencing file 1679 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1680 * from list) 1681 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1682 * 1683 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1684 */ 1685 static char * 1686 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1687 { 1688 char *pathname, *refobj_path; 1689 const char *name; 1690 bool nodeflib, objgiven; 1691 1692 objgiven = refobj != NULL; 1693 1694 if (libmap_disable || !objgiven || 1695 (name = lm_find(refobj->path, xname)) == NULL) 1696 name = xname; 1697 1698 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1699 if (name[0] != '/' && !trust) { 1700 _rtld_error("Absolute pathname required " 1701 "for shared object \"%s\"", name); 1702 return (NULL); 1703 } 1704 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1705 __DECONST(char *, name))); 1706 } 1707 1708 dbg(" Searching for \"%s\"", name); 1709 refobj_path = objgiven ? refobj->path : NULL; 1710 1711 /* 1712 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1713 * back to pre-conforming behaviour if user requested so with 1714 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1715 * nodeflib. 1716 */ 1717 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1718 pathname = search_library_path(name, ld_library_path, 1719 refobj_path, fdp); 1720 if (pathname != NULL) 1721 return (pathname); 1722 if (refobj != NULL) { 1723 pathname = search_library_path(name, refobj->rpath, 1724 refobj_path, fdp); 1725 if (pathname != NULL) 1726 return (pathname); 1727 } 1728 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1729 if (pathname != NULL) 1730 return (pathname); 1731 pathname = search_library_path(name, gethints(false), 1732 refobj_path, fdp); 1733 if (pathname != NULL) 1734 return (pathname); 1735 pathname = search_library_path(name, ld_standard_library_path, 1736 refobj_path, fdp); 1737 if (pathname != NULL) 1738 return (pathname); 1739 } else { 1740 nodeflib = objgiven ? refobj->z_nodeflib : false; 1741 if (objgiven) { 1742 pathname = search_library_path(name, refobj->rpath, 1743 refobj->path, fdp); 1744 if (pathname != NULL) 1745 return (pathname); 1746 } 1747 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1748 pathname = search_library_path(name, obj_main->rpath, 1749 refobj_path, fdp); 1750 if (pathname != NULL) 1751 return (pathname); 1752 } 1753 pathname = search_library_path(name, ld_library_path, 1754 refobj_path, fdp); 1755 if (pathname != NULL) 1756 return (pathname); 1757 if (objgiven) { 1758 pathname = search_library_path(name, refobj->runpath, 1759 refobj_path, fdp); 1760 if (pathname != NULL) 1761 return (pathname); 1762 } 1763 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1764 if (pathname != NULL) 1765 return (pathname); 1766 pathname = search_library_path(name, gethints(nodeflib), 1767 refobj_path, fdp); 1768 if (pathname != NULL) 1769 return (pathname); 1770 if (objgiven && !nodeflib) { 1771 pathname = search_library_path(name, 1772 ld_standard_library_path, refobj_path, fdp); 1773 if (pathname != NULL) 1774 return (pathname); 1775 } 1776 } 1777 1778 if (objgiven && refobj->path != NULL) { 1779 _rtld_error("Shared object \"%s\" not found, " 1780 "required by \"%s\"", name, basename(refobj->path)); 1781 } else { 1782 _rtld_error("Shared object \"%s\" not found", name); 1783 } 1784 return (NULL); 1785 } 1786 1787 /* 1788 * Given a symbol number in a referencing object, find the corresponding 1789 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1790 * no definition was found. Returns a pointer to the Obj_Entry of the 1791 * defining object via the reference parameter DEFOBJ_OUT. 1792 */ 1793 const Elf_Sym * 1794 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1795 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1796 RtldLockState *lockstate) 1797 { 1798 const Elf_Sym *ref; 1799 const Elf_Sym *def; 1800 const Obj_Entry *defobj; 1801 const Ver_Entry *ve; 1802 SymLook req; 1803 const char *name; 1804 int res; 1805 1806 /* 1807 * If we have already found this symbol, get the information from 1808 * the cache. 1809 */ 1810 if (symnum >= refobj->dynsymcount) 1811 return NULL; /* Bad object */ 1812 if (cache != NULL && cache[symnum].sym != NULL) { 1813 *defobj_out = cache[symnum].obj; 1814 return cache[symnum].sym; 1815 } 1816 1817 ref = refobj->symtab + symnum; 1818 name = refobj->strtab + ref->st_name; 1819 def = NULL; 1820 defobj = NULL; 1821 ve = NULL; 1822 1823 /* 1824 * We don't have to do a full scale lookup if the symbol is local. 1825 * We know it will bind to the instance in this load module; to 1826 * which we already have a pointer (ie ref). By not doing a lookup, 1827 * we not only improve performance, but it also avoids unresolvable 1828 * symbols when local symbols are not in the hash table. This has 1829 * been seen with the ia64 toolchain. 1830 */ 1831 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1832 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1833 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1834 symnum); 1835 } 1836 symlook_init(&req, name); 1837 req.flags = flags; 1838 ve = req.ventry = fetch_ventry(refobj, symnum); 1839 req.lockstate = lockstate; 1840 res = symlook_default(&req, refobj); 1841 if (res == 0) { 1842 def = req.sym_out; 1843 defobj = req.defobj_out; 1844 } 1845 } else { 1846 def = ref; 1847 defobj = refobj; 1848 } 1849 1850 /* 1851 * If we found no definition and the reference is weak, treat the 1852 * symbol as having the value zero. 1853 */ 1854 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1855 def = &sym_zero; 1856 defobj = obj_main; 1857 } 1858 1859 if (def != NULL) { 1860 *defobj_out = defobj; 1861 /* Record the information in the cache to avoid subsequent lookups. */ 1862 if (cache != NULL) { 1863 cache[symnum].sym = def; 1864 cache[symnum].obj = defobj; 1865 } 1866 } else { 1867 if (refobj != &obj_rtld) 1868 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1869 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1870 } 1871 return def; 1872 } 1873 1874 /* 1875 * Return the search path from the ldconfig hints file, reading it if 1876 * necessary. If nostdlib is true, then the default search paths are 1877 * not added to result. 1878 * 1879 * Returns NULL if there are problems with the hints file, 1880 * or if the search path there is empty. 1881 */ 1882 static const char * 1883 gethints(bool nostdlib) 1884 { 1885 static char *filtered_path; 1886 static const char *hints; 1887 static struct elfhints_hdr hdr; 1888 struct fill_search_info_args sargs, hargs; 1889 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1890 struct dl_serpath *SLPpath, *hintpath; 1891 char *p; 1892 struct stat hint_stat; 1893 unsigned int SLPndx, hintndx, fndx, fcount; 1894 int fd; 1895 size_t flen; 1896 uint32_t dl; 1897 bool skip; 1898 1899 /* First call, read the hints file */ 1900 if (hints == NULL) { 1901 /* Keep from trying again in case the hints file is bad. */ 1902 hints = ""; 1903 1904 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1905 return (NULL); 1906 1907 /* 1908 * Check of hdr.dirlistlen value against type limit 1909 * intends to pacify static analyzers. Further 1910 * paranoia leads to checks that dirlist is fully 1911 * contained in the file range. 1912 */ 1913 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1914 hdr.magic != ELFHINTS_MAGIC || 1915 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1916 fstat(fd, &hint_stat) == -1) { 1917 cleanup1: 1918 close(fd); 1919 hdr.dirlistlen = 0; 1920 return (NULL); 1921 } 1922 dl = hdr.strtab; 1923 if (dl + hdr.dirlist < dl) 1924 goto cleanup1; 1925 dl += hdr.dirlist; 1926 if (dl + hdr.dirlistlen < dl) 1927 goto cleanup1; 1928 dl += hdr.dirlistlen; 1929 if (dl > hint_stat.st_size) 1930 goto cleanup1; 1931 p = xmalloc(hdr.dirlistlen + 1); 1932 if (pread(fd, p, hdr.dirlistlen + 1, 1933 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1934 p[hdr.dirlistlen] != '\0') { 1935 free(p); 1936 goto cleanup1; 1937 } 1938 hints = p; 1939 close(fd); 1940 } 1941 1942 /* 1943 * If caller agreed to receive list which includes the default 1944 * paths, we are done. Otherwise, if we still did not 1945 * calculated filtered result, do it now. 1946 */ 1947 if (!nostdlib) 1948 return (hints[0] != '\0' ? hints : NULL); 1949 if (filtered_path != NULL) 1950 goto filt_ret; 1951 1952 /* 1953 * Obtain the list of all configured search paths, and the 1954 * list of the default paths. 1955 * 1956 * First estimate the size of the results. 1957 */ 1958 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1959 smeta.dls_cnt = 0; 1960 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1961 hmeta.dls_cnt = 0; 1962 1963 sargs.request = RTLD_DI_SERINFOSIZE; 1964 sargs.serinfo = &smeta; 1965 hargs.request = RTLD_DI_SERINFOSIZE; 1966 hargs.serinfo = &hmeta; 1967 1968 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1969 &sargs); 1970 path_enumerate(hints, fill_search_info, NULL, &hargs); 1971 1972 SLPinfo = xmalloc(smeta.dls_size); 1973 hintinfo = xmalloc(hmeta.dls_size); 1974 1975 /* 1976 * Next fetch both sets of paths. 1977 */ 1978 sargs.request = RTLD_DI_SERINFO; 1979 sargs.serinfo = SLPinfo; 1980 sargs.serpath = &SLPinfo->dls_serpath[0]; 1981 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1982 1983 hargs.request = RTLD_DI_SERINFO; 1984 hargs.serinfo = hintinfo; 1985 hargs.serpath = &hintinfo->dls_serpath[0]; 1986 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1987 1988 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1989 &sargs); 1990 path_enumerate(hints, fill_search_info, NULL, &hargs); 1991 1992 /* 1993 * Now calculate the difference between two sets, by excluding 1994 * standard paths from the full set. 1995 */ 1996 fndx = 0; 1997 fcount = 0; 1998 filtered_path = xmalloc(hdr.dirlistlen + 1); 1999 hintpath = &hintinfo->dls_serpath[0]; 2000 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2001 skip = false; 2002 SLPpath = &SLPinfo->dls_serpath[0]; 2003 /* 2004 * Check each standard path against current. 2005 */ 2006 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2007 /* matched, skip the path */ 2008 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2009 skip = true; 2010 break; 2011 } 2012 } 2013 if (skip) 2014 continue; 2015 /* 2016 * Not matched against any standard path, add the path 2017 * to result. Separate consequtive paths with ':'. 2018 */ 2019 if (fcount > 0) { 2020 filtered_path[fndx] = ':'; 2021 fndx++; 2022 } 2023 fcount++; 2024 flen = strlen(hintpath->dls_name); 2025 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2026 fndx += flen; 2027 } 2028 filtered_path[fndx] = '\0'; 2029 2030 free(SLPinfo); 2031 free(hintinfo); 2032 2033 filt_ret: 2034 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2035 } 2036 2037 static void 2038 init_dag(Obj_Entry *root) 2039 { 2040 const Needed_Entry *needed; 2041 const Objlist_Entry *elm; 2042 DoneList donelist; 2043 2044 if (root->dag_inited) 2045 return; 2046 donelist_init(&donelist); 2047 2048 /* Root object belongs to own DAG. */ 2049 objlist_push_tail(&root->dldags, root); 2050 objlist_push_tail(&root->dagmembers, root); 2051 donelist_check(&donelist, root); 2052 2053 /* 2054 * Add dependencies of root object to DAG in breadth order 2055 * by exploiting the fact that each new object get added 2056 * to the tail of the dagmembers list. 2057 */ 2058 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2059 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2060 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2061 continue; 2062 objlist_push_tail(&needed->obj->dldags, root); 2063 objlist_push_tail(&root->dagmembers, needed->obj); 2064 } 2065 } 2066 root->dag_inited = true; 2067 } 2068 2069 static void 2070 init_marker(Obj_Entry *marker) 2071 { 2072 2073 bzero(marker, sizeof(*marker)); 2074 marker->marker = true; 2075 } 2076 2077 Obj_Entry * 2078 globallist_curr(const Obj_Entry *obj) 2079 { 2080 2081 for (;;) { 2082 if (obj == NULL) 2083 return (NULL); 2084 if (!obj->marker) 2085 return (__DECONST(Obj_Entry *, obj)); 2086 obj = TAILQ_PREV(obj, obj_entry_q, next); 2087 } 2088 } 2089 2090 Obj_Entry * 2091 globallist_next(const Obj_Entry *obj) 2092 { 2093 2094 for (;;) { 2095 obj = TAILQ_NEXT(obj, next); 2096 if (obj == NULL) 2097 return (NULL); 2098 if (!obj->marker) 2099 return (__DECONST(Obj_Entry *, obj)); 2100 } 2101 } 2102 2103 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2104 static void 2105 hold_object(Obj_Entry *obj) 2106 { 2107 2108 obj->holdcount++; 2109 } 2110 2111 static void 2112 unhold_object(Obj_Entry *obj) 2113 { 2114 2115 assert(obj->holdcount > 0); 2116 if (--obj->holdcount == 0 && obj->unholdfree) 2117 release_object(obj); 2118 } 2119 2120 static void 2121 process_z(Obj_Entry *root) 2122 { 2123 const Objlist_Entry *elm; 2124 Obj_Entry *obj; 2125 2126 /* 2127 * Walk over object DAG and process every dependent object 2128 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2129 * to grow their own DAG. 2130 * 2131 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2132 * symlook_global() to work. 2133 * 2134 * For DF_1_NODELETE, the DAG should have its reference upped. 2135 */ 2136 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2137 obj = elm->obj; 2138 if (obj == NULL) 2139 continue; 2140 if (obj->z_nodelete && !obj->ref_nodel) { 2141 dbg("obj %s -z nodelete", obj->path); 2142 init_dag(obj); 2143 ref_dag(obj); 2144 obj->ref_nodel = true; 2145 } 2146 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2147 dbg("obj %s -z global", obj->path); 2148 objlist_push_tail(&list_global, obj); 2149 init_dag(obj); 2150 } 2151 } 2152 } 2153 /* 2154 * Initialize the dynamic linker. The argument is the address at which 2155 * the dynamic linker has been mapped into memory. The primary task of 2156 * this function is to relocate the dynamic linker. 2157 */ 2158 static void 2159 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2160 { 2161 Obj_Entry objtmp; /* Temporary rtld object */ 2162 const Elf_Ehdr *ehdr; 2163 const Elf_Dyn *dyn_rpath; 2164 const Elf_Dyn *dyn_soname; 2165 const Elf_Dyn *dyn_runpath; 2166 2167 #ifdef RTLD_INIT_PAGESIZES_EARLY 2168 /* The page size is required by the dynamic memory allocator. */ 2169 init_pagesizes(aux_info); 2170 #endif 2171 2172 /* 2173 * Conjure up an Obj_Entry structure for the dynamic linker. 2174 * 2175 * The "path" member can't be initialized yet because string constants 2176 * cannot yet be accessed. Below we will set it correctly. 2177 */ 2178 memset(&objtmp, 0, sizeof(objtmp)); 2179 objtmp.path = NULL; 2180 objtmp.rtld = true; 2181 objtmp.mapbase = mapbase; 2182 #ifdef PIC 2183 objtmp.relocbase = mapbase; 2184 #endif 2185 2186 objtmp.dynamic = rtld_dynamic(&objtmp); 2187 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2188 assert(objtmp.needed == NULL); 2189 #if !defined(__mips__) 2190 /* MIPS has a bogus DT_TEXTREL. */ 2191 assert(!objtmp.textrel); 2192 #endif 2193 /* 2194 * Temporarily put the dynamic linker entry into the object list, so 2195 * that symbols can be found. 2196 */ 2197 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2198 2199 ehdr = (Elf_Ehdr *)mapbase; 2200 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2201 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2202 2203 /* Initialize the object list. */ 2204 TAILQ_INIT(&obj_list); 2205 2206 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2207 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2208 2209 #ifndef RTLD_INIT_PAGESIZES_EARLY 2210 /* The page size is required by the dynamic memory allocator. */ 2211 init_pagesizes(aux_info); 2212 #endif 2213 2214 if (aux_info[AT_OSRELDATE] != NULL) 2215 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2216 2217 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2218 2219 /* Replace the path with a dynamically allocated copy. */ 2220 obj_rtld.path = xstrdup(ld_path_rtld); 2221 2222 r_debug.r_brk = r_debug_state; 2223 r_debug.r_state = RT_CONSISTENT; 2224 } 2225 2226 /* 2227 * Retrieve the array of supported page sizes. The kernel provides the page 2228 * sizes in increasing order. 2229 */ 2230 static void 2231 init_pagesizes(Elf_Auxinfo **aux_info) 2232 { 2233 static size_t psa[MAXPAGESIZES]; 2234 int mib[2]; 2235 size_t len, size; 2236 2237 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2238 NULL) { 2239 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2240 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2241 } else { 2242 len = 2; 2243 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2244 size = sizeof(psa); 2245 else { 2246 /* As a fallback, retrieve the base page size. */ 2247 size = sizeof(psa[0]); 2248 if (aux_info[AT_PAGESZ] != NULL) { 2249 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2250 goto psa_filled; 2251 } else { 2252 mib[0] = CTL_HW; 2253 mib[1] = HW_PAGESIZE; 2254 len = 2; 2255 } 2256 } 2257 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2258 _rtld_error("sysctl for hw.pagesize(s) failed"); 2259 rtld_die(); 2260 } 2261 psa_filled: 2262 pagesizes = psa; 2263 } 2264 npagesizes = size / sizeof(pagesizes[0]); 2265 /* Discard any invalid entries at the end of the array. */ 2266 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2267 npagesizes--; 2268 } 2269 2270 /* 2271 * Add the init functions from a needed object list (and its recursive 2272 * needed objects) to "list". This is not used directly; it is a helper 2273 * function for initlist_add_objects(). The write lock must be held 2274 * when this function is called. 2275 */ 2276 static void 2277 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2278 { 2279 /* Recursively process the successor needed objects. */ 2280 if (needed->next != NULL) 2281 initlist_add_neededs(needed->next, list); 2282 2283 /* Process the current needed object. */ 2284 if (needed->obj != NULL) 2285 initlist_add_objects(needed->obj, needed->obj, list); 2286 } 2287 2288 /* 2289 * Scan all of the DAGs rooted in the range of objects from "obj" to 2290 * "tail" and add their init functions to "list". This recurses over 2291 * the DAGs and ensure the proper init ordering such that each object's 2292 * needed libraries are initialized before the object itself. At the 2293 * same time, this function adds the objects to the global finalization 2294 * list "list_fini" in the opposite order. The write lock must be 2295 * held when this function is called. 2296 */ 2297 static void 2298 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2299 { 2300 Obj_Entry *nobj; 2301 2302 if (obj->init_scanned || obj->init_done) 2303 return; 2304 obj->init_scanned = true; 2305 2306 /* Recursively process the successor objects. */ 2307 nobj = globallist_next(obj); 2308 if (nobj != NULL && obj != tail) 2309 initlist_add_objects(nobj, tail, list); 2310 2311 /* Recursively process the needed objects. */ 2312 if (obj->needed != NULL) 2313 initlist_add_neededs(obj->needed, list); 2314 if (obj->needed_filtees != NULL) 2315 initlist_add_neededs(obj->needed_filtees, list); 2316 if (obj->needed_aux_filtees != NULL) 2317 initlist_add_neededs(obj->needed_aux_filtees, list); 2318 2319 /* Add the object to the init list. */ 2320 objlist_push_tail(list, obj); 2321 2322 /* Add the object to the global fini list in the reverse order. */ 2323 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2324 && !obj->on_fini_list) { 2325 objlist_push_head(&list_fini, obj); 2326 obj->on_fini_list = true; 2327 } 2328 } 2329 2330 #ifndef FPTR_TARGET 2331 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2332 #endif 2333 2334 static void 2335 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2336 { 2337 Needed_Entry *needed, *needed1; 2338 2339 for (needed = n; needed != NULL; needed = needed->next) { 2340 if (needed->obj != NULL) { 2341 dlclose_locked(needed->obj, lockstate); 2342 needed->obj = NULL; 2343 } 2344 } 2345 for (needed = n; needed != NULL; needed = needed1) { 2346 needed1 = needed->next; 2347 free(needed); 2348 } 2349 } 2350 2351 static void 2352 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2353 { 2354 2355 free_needed_filtees(obj->needed_filtees, lockstate); 2356 obj->needed_filtees = NULL; 2357 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2358 obj->needed_aux_filtees = NULL; 2359 obj->filtees_loaded = false; 2360 } 2361 2362 static void 2363 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2364 RtldLockState *lockstate) 2365 { 2366 2367 for (; needed != NULL; needed = needed->next) { 2368 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2369 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2370 RTLD_LOCAL, lockstate); 2371 } 2372 } 2373 2374 static void 2375 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2376 { 2377 2378 lock_restart_for_upgrade(lockstate); 2379 if (!obj->filtees_loaded) { 2380 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2381 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2382 obj->filtees_loaded = true; 2383 } 2384 } 2385 2386 static int 2387 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2388 { 2389 Obj_Entry *obj1; 2390 2391 for (; needed != NULL; needed = needed->next) { 2392 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2393 flags & ~RTLD_LO_NOLOAD); 2394 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2395 return (-1); 2396 } 2397 return (0); 2398 } 2399 2400 /* 2401 * Given a shared object, traverse its list of needed objects, and load 2402 * each of them. Returns 0 on success. Generates an error message and 2403 * returns -1 on failure. 2404 */ 2405 static int 2406 load_needed_objects(Obj_Entry *first, int flags) 2407 { 2408 Obj_Entry *obj; 2409 2410 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2411 if (obj->marker) 2412 continue; 2413 if (process_needed(obj, obj->needed, flags) == -1) 2414 return (-1); 2415 } 2416 return (0); 2417 } 2418 2419 static int 2420 load_preload_objects(void) 2421 { 2422 char *p = ld_preload; 2423 Obj_Entry *obj; 2424 static const char delim[] = " \t:;"; 2425 2426 if (p == NULL) 2427 return 0; 2428 2429 p += strspn(p, delim); 2430 while (*p != '\0') { 2431 size_t len = strcspn(p, delim); 2432 char savech; 2433 2434 savech = p[len]; 2435 p[len] = '\0'; 2436 obj = load_object(p, -1, NULL, 0); 2437 if (obj == NULL) 2438 return -1; /* XXX - cleanup */ 2439 obj->z_interpose = true; 2440 p[len] = savech; 2441 p += len; 2442 p += strspn(p, delim); 2443 } 2444 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2445 return 0; 2446 } 2447 2448 static const char * 2449 printable_path(const char *path) 2450 { 2451 2452 return (path == NULL ? "<unknown>" : path); 2453 } 2454 2455 /* 2456 * Load a shared object into memory, if it is not already loaded. The 2457 * object may be specified by name or by user-supplied file descriptor 2458 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2459 * duplicate is. 2460 * 2461 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2462 * on failure. 2463 */ 2464 static Obj_Entry * 2465 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2466 { 2467 Obj_Entry *obj; 2468 int fd; 2469 struct stat sb; 2470 char *path; 2471 2472 fd = -1; 2473 if (name != NULL) { 2474 TAILQ_FOREACH(obj, &obj_list, next) { 2475 if (obj->marker || obj->doomed) 2476 continue; 2477 if (object_match_name(obj, name)) 2478 return (obj); 2479 } 2480 2481 path = find_library(name, refobj, &fd); 2482 if (path == NULL) 2483 return (NULL); 2484 } else 2485 path = NULL; 2486 2487 if (fd >= 0) { 2488 /* 2489 * search_library_pathfds() opens a fresh file descriptor for the 2490 * library, so there is no need to dup(). 2491 */ 2492 } else if (fd_u == -1) { 2493 /* 2494 * If we didn't find a match by pathname, or the name is not 2495 * supplied, open the file and check again by device and inode. 2496 * This avoids false mismatches caused by multiple links or ".." 2497 * in pathnames. 2498 * 2499 * To avoid a race, we open the file and use fstat() rather than 2500 * using stat(). 2501 */ 2502 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2503 _rtld_error("Cannot open \"%s\"", path); 2504 free(path); 2505 return (NULL); 2506 } 2507 } else { 2508 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2509 if (fd == -1) { 2510 _rtld_error("Cannot dup fd"); 2511 free(path); 2512 return (NULL); 2513 } 2514 } 2515 if (fstat(fd, &sb) == -1) { 2516 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2517 close(fd); 2518 free(path); 2519 return NULL; 2520 } 2521 TAILQ_FOREACH(obj, &obj_list, next) { 2522 if (obj->marker || obj->doomed) 2523 continue; 2524 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2525 break; 2526 } 2527 if (obj != NULL && name != NULL) { 2528 object_add_name(obj, name); 2529 free(path); 2530 close(fd); 2531 return obj; 2532 } 2533 if (flags & RTLD_LO_NOLOAD) { 2534 free(path); 2535 close(fd); 2536 return (NULL); 2537 } 2538 2539 /* First use of this object, so we must map it in */ 2540 obj = do_load_object(fd, name, path, &sb, flags); 2541 if (obj == NULL) 2542 free(path); 2543 close(fd); 2544 2545 return obj; 2546 } 2547 2548 static Obj_Entry * 2549 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2550 int flags) 2551 { 2552 Obj_Entry *obj; 2553 struct statfs fs; 2554 2555 /* 2556 * but first, make sure that environment variables haven't been 2557 * used to circumvent the noexec flag on a filesystem. 2558 */ 2559 if (dangerous_ld_env) { 2560 if (fstatfs(fd, &fs) != 0) { 2561 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2562 return NULL; 2563 } 2564 if (fs.f_flags & MNT_NOEXEC) { 2565 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2566 return NULL; 2567 } 2568 } 2569 dbg("loading \"%s\"", printable_path(path)); 2570 obj = map_object(fd, printable_path(path), sbp); 2571 if (obj == NULL) 2572 return NULL; 2573 2574 /* 2575 * If DT_SONAME is present in the object, digest_dynamic2 already 2576 * added it to the object names. 2577 */ 2578 if (name != NULL) 2579 object_add_name(obj, name); 2580 obj->path = path; 2581 if (!digest_dynamic(obj, 0)) 2582 goto errp; 2583 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2584 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2585 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2586 RTLD_LO_DLOPEN) { 2587 dbg("refusing to load non-loadable \"%s\"", obj->path); 2588 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2589 goto errp; 2590 } 2591 2592 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2593 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2594 obj_count++; 2595 obj_loads++; 2596 linkmap_add(obj); /* for GDB & dlinfo() */ 2597 max_stack_flags |= obj->stack_flags; 2598 2599 dbg(" %p .. %p: %s", obj->mapbase, 2600 obj->mapbase + obj->mapsize - 1, obj->path); 2601 if (obj->textrel) 2602 dbg(" WARNING: %s has impure text", obj->path); 2603 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2604 obj->path); 2605 2606 return (obj); 2607 2608 errp: 2609 munmap(obj->mapbase, obj->mapsize); 2610 obj_free(obj); 2611 return (NULL); 2612 } 2613 2614 static Obj_Entry * 2615 obj_from_addr(const void *addr) 2616 { 2617 Obj_Entry *obj; 2618 2619 TAILQ_FOREACH(obj, &obj_list, next) { 2620 if (obj->marker) 2621 continue; 2622 if (addr < (void *) obj->mapbase) 2623 continue; 2624 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2625 return obj; 2626 } 2627 return NULL; 2628 } 2629 2630 static void 2631 preinit_main(void) 2632 { 2633 Elf_Addr *preinit_addr; 2634 int index; 2635 2636 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2637 if (preinit_addr == NULL) 2638 return; 2639 2640 for (index = 0; index < obj_main->preinit_array_num; index++) { 2641 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2642 dbg("calling preinit function for %s at %p", obj_main->path, 2643 (void *)preinit_addr[index]); 2644 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2645 0, 0, obj_main->path); 2646 call_init_pointer(obj_main, preinit_addr[index]); 2647 } 2648 } 2649 } 2650 2651 /* 2652 * Call the finalization functions for each of the objects in "list" 2653 * belonging to the DAG of "root" and referenced once. If NULL "root" 2654 * is specified, every finalization function will be called regardless 2655 * of the reference count and the list elements won't be freed. All of 2656 * the objects are expected to have non-NULL fini functions. 2657 */ 2658 static void 2659 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2660 { 2661 Objlist_Entry *elm; 2662 char *saved_msg; 2663 Elf_Addr *fini_addr; 2664 int index; 2665 2666 assert(root == NULL || root->refcount == 1); 2667 2668 if (root != NULL) 2669 root->doomed = true; 2670 2671 /* 2672 * Preserve the current error message since a fini function might 2673 * call into the dynamic linker and overwrite it. 2674 */ 2675 saved_msg = errmsg_save(); 2676 do { 2677 STAILQ_FOREACH(elm, list, link) { 2678 if (root != NULL && (elm->obj->refcount != 1 || 2679 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2680 continue; 2681 /* Remove object from fini list to prevent recursive invocation. */ 2682 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2683 /* Ensure that new references cannot be acquired. */ 2684 elm->obj->doomed = true; 2685 2686 hold_object(elm->obj); 2687 lock_release(rtld_bind_lock, lockstate); 2688 /* 2689 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2690 * When this happens, DT_FINI_ARRAY is processed first. 2691 */ 2692 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2693 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2694 for (index = elm->obj->fini_array_num - 1; index >= 0; 2695 index--) { 2696 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2697 dbg("calling fini function for %s at %p", 2698 elm->obj->path, (void *)fini_addr[index]); 2699 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2700 (void *)fini_addr[index], 0, 0, elm->obj->path); 2701 call_initfini_pointer(elm->obj, fini_addr[index]); 2702 } 2703 } 2704 } 2705 if (elm->obj->fini != (Elf_Addr)NULL) { 2706 dbg("calling fini function for %s at %p", elm->obj->path, 2707 (void *)elm->obj->fini); 2708 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2709 0, 0, elm->obj->path); 2710 call_initfini_pointer(elm->obj, elm->obj->fini); 2711 } 2712 wlock_acquire(rtld_bind_lock, lockstate); 2713 unhold_object(elm->obj); 2714 /* No need to free anything if process is going down. */ 2715 if (root != NULL) 2716 free(elm); 2717 /* 2718 * We must restart the list traversal after every fini call 2719 * because a dlclose() call from the fini function or from 2720 * another thread might have modified the reference counts. 2721 */ 2722 break; 2723 } 2724 } while (elm != NULL); 2725 errmsg_restore(saved_msg); 2726 } 2727 2728 /* 2729 * Call the initialization functions for each of the objects in 2730 * "list". All of the objects are expected to have non-NULL init 2731 * functions. 2732 */ 2733 static void 2734 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2735 { 2736 Objlist_Entry *elm; 2737 Obj_Entry *obj; 2738 char *saved_msg; 2739 Elf_Addr *init_addr; 2740 void (*reg)(void (*)(void)); 2741 int index; 2742 2743 /* 2744 * Clean init_scanned flag so that objects can be rechecked and 2745 * possibly initialized earlier if any of vectors called below 2746 * cause the change by using dlopen. 2747 */ 2748 TAILQ_FOREACH(obj, &obj_list, next) { 2749 if (obj->marker) 2750 continue; 2751 obj->init_scanned = false; 2752 } 2753 2754 /* 2755 * Preserve the current error message since an init function might 2756 * call into the dynamic linker and overwrite it. 2757 */ 2758 saved_msg = errmsg_save(); 2759 STAILQ_FOREACH(elm, list, link) { 2760 if (elm->obj->init_done) /* Initialized early. */ 2761 continue; 2762 /* 2763 * Race: other thread might try to use this object before current 2764 * one completes the initialization. Not much can be done here 2765 * without better locking. 2766 */ 2767 elm->obj->init_done = true; 2768 hold_object(elm->obj); 2769 reg = NULL; 2770 if (elm->obj == obj_main && obj_main->crt_no_init) { 2771 reg = (void (*)(void (*)(void)))get_program_var_addr( 2772 "__libc_atexit", lockstate); 2773 } 2774 lock_release(rtld_bind_lock, lockstate); 2775 if (reg != NULL) { 2776 reg(rtld_exit); 2777 rtld_exit_ptr = rtld_nop_exit; 2778 } 2779 2780 /* 2781 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2782 * When this happens, DT_INIT is processed first. 2783 */ 2784 if (elm->obj->init != (Elf_Addr)NULL) { 2785 dbg("calling init function for %s at %p", elm->obj->path, 2786 (void *)elm->obj->init); 2787 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2788 0, 0, elm->obj->path); 2789 call_initfini_pointer(elm->obj, elm->obj->init); 2790 } 2791 init_addr = (Elf_Addr *)elm->obj->init_array; 2792 if (init_addr != NULL) { 2793 for (index = 0; index < elm->obj->init_array_num; index++) { 2794 if (init_addr[index] != 0 && init_addr[index] != 1) { 2795 dbg("calling init function for %s at %p", elm->obj->path, 2796 (void *)init_addr[index]); 2797 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2798 (void *)init_addr[index], 0, 0, elm->obj->path); 2799 call_init_pointer(elm->obj, init_addr[index]); 2800 } 2801 } 2802 } 2803 wlock_acquire(rtld_bind_lock, lockstate); 2804 unhold_object(elm->obj); 2805 } 2806 errmsg_restore(saved_msg); 2807 } 2808 2809 static void 2810 objlist_clear(Objlist *list) 2811 { 2812 Objlist_Entry *elm; 2813 2814 while (!STAILQ_EMPTY(list)) { 2815 elm = STAILQ_FIRST(list); 2816 STAILQ_REMOVE_HEAD(list, link); 2817 free(elm); 2818 } 2819 } 2820 2821 static Objlist_Entry * 2822 objlist_find(Objlist *list, const Obj_Entry *obj) 2823 { 2824 Objlist_Entry *elm; 2825 2826 STAILQ_FOREACH(elm, list, link) 2827 if (elm->obj == obj) 2828 return elm; 2829 return NULL; 2830 } 2831 2832 static void 2833 objlist_init(Objlist *list) 2834 { 2835 STAILQ_INIT(list); 2836 } 2837 2838 static void 2839 objlist_push_head(Objlist *list, Obj_Entry *obj) 2840 { 2841 Objlist_Entry *elm; 2842 2843 elm = NEW(Objlist_Entry); 2844 elm->obj = obj; 2845 STAILQ_INSERT_HEAD(list, elm, link); 2846 } 2847 2848 static void 2849 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2850 { 2851 Objlist_Entry *elm; 2852 2853 elm = NEW(Objlist_Entry); 2854 elm->obj = obj; 2855 STAILQ_INSERT_TAIL(list, elm, link); 2856 } 2857 2858 static void 2859 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2860 { 2861 Objlist_Entry *elm, *listelm; 2862 2863 STAILQ_FOREACH(listelm, list, link) { 2864 if (listelm->obj == listobj) 2865 break; 2866 } 2867 elm = NEW(Objlist_Entry); 2868 elm->obj = obj; 2869 if (listelm != NULL) 2870 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2871 else 2872 STAILQ_INSERT_TAIL(list, elm, link); 2873 } 2874 2875 static void 2876 objlist_remove(Objlist *list, Obj_Entry *obj) 2877 { 2878 Objlist_Entry *elm; 2879 2880 if ((elm = objlist_find(list, obj)) != NULL) { 2881 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2882 free(elm); 2883 } 2884 } 2885 2886 /* 2887 * Relocate dag rooted in the specified object. 2888 * Returns 0 on success, or -1 on failure. 2889 */ 2890 2891 static int 2892 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2893 int flags, RtldLockState *lockstate) 2894 { 2895 Objlist_Entry *elm; 2896 int error; 2897 2898 error = 0; 2899 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2900 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2901 lockstate); 2902 if (error == -1) 2903 break; 2904 } 2905 return (error); 2906 } 2907 2908 /* 2909 * Prepare for, or clean after, relocating an object marked with 2910 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2911 * segments are remapped read-write. After relocations are done, the 2912 * segment's permissions are returned back to the modes specified in 2913 * the phdrs. If any relocation happened, or always for wired 2914 * program, COW is triggered. 2915 */ 2916 static int 2917 reloc_textrel_prot(Obj_Entry *obj, bool before) 2918 { 2919 const Elf_Phdr *ph; 2920 void *base; 2921 size_t l, sz; 2922 int prot; 2923 2924 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2925 l--, ph++) { 2926 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2927 continue; 2928 base = obj->relocbase + trunc_page(ph->p_vaddr); 2929 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2930 trunc_page(ph->p_vaddr); 2931 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2932 if (mprotect(base, sz, prot) == -1) { 2933 _rtld_error("%s: Cannot write-%sable text segment: %s", 2934 obj->path, before ? "en" : "dis", 2935 rtld_strerror(errno)); 2936 return (-1); 2937 } 2938 } 2939 return (0); 2940 } 2941 2942 /* 2943 * Relocate single object. 2944 * Returns 0 on success, or -1 on failure. 2945 */ 2946 static int 2947 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2948 int flags, RtldLockState *lockstate) 2949 { 2950 2951 if (obj->relocated) 2952 return (0); 2953 obj->relocated = true; 2954 if (obj != rtldobj) 2955 dbg("relocating \"%s\"", obj->path); 2956 2957 if (obj->symtab == NULL || obj->strtab == NULL || 2958 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2959 _rtld_error("%s: Shared object has no run-time symbol table", 2960 obj->path); 2961 return (-1); 2962 } 2963 2964 /* There are relocations to the write-protected text segment. */ 2965 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2966 return (-1); 2967 2968 /* Process the non-PLT non-IFUNC relocations. */ 2969 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2970 return (-1); 2971 2972 /* Re-protected the text segment. */ 2973 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2974 return (-1); 2975 2976 /* Set the special PLT or GOT entries. */ 2977 init_pltgot(obj); 2978 2979 /* Process the PLT relocations. */ 2980 if (reloc_plt(obj, flags, lockstate) == -1) 2981 return (-1); 2982 /* Relocate the jump slots if we are doing immediate binding. */ 2983 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2984 lockstate) == -1) 2985 return (-1); 2986 2987 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2988 return (-1); 2989 2990 /* 2991 * Set up the magic number and version in the Obj_Entry. These 2992 * were checked in the crt1.o from the original ElfKit, so we 2993 * set them for backward compatibility. 2994 */ 2995 obj->magic = RTLD_MAGIC; 2996 obj->version = RTLD_VERSION; 2997 2998 return (0); 2999 } 3000 3001 /* 3002 * Relocate newly-loaded shared objects. The argument is a pointer to 3003 * the Obj_Entry for the first such object. All objects from the first 3004 * to the end of the list of objects are relocated. Returns 0 on success, 3005 * or -1 on failure. 3006 */ 3007 static int 3008 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3009 int flags, RtldLockState *lockstate) 3010 { 3011 Obj_Entry *obj; 3012 int error; 3013 3014 for (error = 0, obj = first; obj != NULL; 3015 obj = TAILQ_NEXT(obj, next)) { 3016 if (obj->marker) 3017 continue; 3018 error = relocate_object(obj, bind_now, rtldobj, flags, 3019 lockstate); 3020 if (error == -1) 3021 break; 3022 } 3023 return (error); 3024 } 3025 3026 /* 3027 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3028 * referencing STT_GNU_IFUNC symbols is postponed till the other 3029 * relocations are done. The indirect functions specified as 3030 * ifunc are allowed to call other symbols, so we need to have 3031 * objects relocated before asking for resolution from indirects. 3032 * 3033 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3034 * instead of the usual lazy handling of PLT slots. It is 3035 * consistent with how GNU does it. 3036 */ 3037 static int 3038 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3039 RtldLockState *lockstate) 3040 { 3041 3042 if (obj->ifuncs_resolved) 3043 return (0); 3044 obj->ifuncs_resolved = true; 3045 if (!obj->irelative && !obj->irelative_nonplt && 3046 !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3047 return (0); 3048 if (obj_disable_relro(obj) == -1 || 3049 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3050 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3051 lockstate) == -1) || 3052 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3053 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3054 obj_enforce_relro(obj) == -1) 3055 return (-1); 3056 return (0); 3057 } 3058 3059 static int 3060 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3061 RtldLockState *lockstate) 3062 { 3063 Objlist_Entry *elm; 3064 Obj_Entry *obj; 3065 3066 STAILQ_FOREACH(elm, list, link) { 3067 obj = elm->obj; 3068 if (obj->marker) 3069 continue; 3070 if (resolve_object_ifunc(obj, bind_now, flags, 3071 lockstate) == -1) 3072 return (-1); 3073 } 3074 return (0); 3075 } 3076 3077 /* 3078 * Cleanup procedure. It will be called (by the atexit mechanism) just 3079 * before the process exits. 3080 */ 3081 static void 3082 rtld_exit(void) 3083 { 3084 RtldLockState lockstate; 3085 3086 wlock_acquire(rtld_bind_lock, &lockstate); 3087 dbg("rtld_exit()"); 3088 objlist_call_fini(&list_fini, NULL, &lockstate); 3089 /* No need to remove the items from the list, since we are exiting. */ 3090 if (!libmap_disable) 3091 lm_fini(); 3092 lock_release(rtld_bind_lock, &lockstate); 3093 } 3094 3095 static void 3096 rtld_nop_exit(void) 3097 { 3098 } 3099 3100 /* 3101 * Iterate over a search path, translate each element, and invoke the 3102 * callback on the result. 3103 */ 3104 static void * 3105 path_enumerate(const char *path, path_enum_proc callback, 3106 const char *refobj_path, void *arg) 3107 { 3108 const char *trans; 3109 if (path == NULL) 3110 return (NULL); 3111 3112 path += strspn(path, ":;"); 3113 while (*path != '\0') { 3114 size_t len; 3115 char *res; 3116 3117 len = strcspn(path, ":;"); 3118 trans = lm_findn(refobj_path, path, len); 3119 if (trans) 3120 res = callback(trans, strlen(trans), arg); 3121 else 3122 res = callback(path, len, arg); 3123 3124 if (res != NULL) 3125 return (res); 3126 3127 path += len; 3128 path += strspn(path, ":;"); 3129 } 3130 3131 return (NULL); 3132 } 3133 3134 struct try_library_args { 3135 const char *name; 3136 size_t namelen; 3137 char *buffer; 3138 size_t buflen; 3139 int fd; 3140 }; 3141 3142 static void * 3143 try_library_path(const char *dir, size_t dirlen, void *param) 3144 { 3145 struct try_library_args *arg; 3146 int fd; 3147 3148 arg = param; 3149 if (*dir == '/' || trust) { 3150 char *pathname; 3151 3152 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3153 return (NULL); 3154 3155 pathname = arg->buffer; 3156 strncpy(pathname, dir, dirlen); 3157 pathname[dirlen] = '/'; 3158 strcpy(pathname + dirlen + 1, arg->name); 3159 3160 dbg(" Trying \"%s\"", pathname); 3161 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3162 if (fd >= 0) { 3163 dbg(" Opened \"%s\", fd %d", pathname, fd); 3164 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3165 strcpy(pathname, arg->buffer); 3166 arg->fd = fd; 3167 return (pathname); 3168 } else { 3169 dbg(" Failed to open \"%s\": %s", 3170 pathname, rtld_strerror(errno)); 3171 } 3172 } 3173 return (NULL); 3174 } 3175 3176 static char * 3177 search_library_path(const char *name, const char *path, 3178 const char *refobj_path, int *fdp) 3179 { 3180 char *p; 3181 struct try_library_args arg; 3182 3183 if (path == NULL) 3184 return NULL; 3185 3186 arg.name = name; 3187 arg.namelen = strlen(name); 3188 arg.buffer = xmalloc(PATH_MAX); 3189 arg.buflen = PATH_MAX; 3190 arg.fd = -1; 3191 3192 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3193 *fdp = arg.fd; 3194 3195 free(arg.buffer); 3196 3197 return (p); 3198 } 3199 3200 3201 /* 3202 * Finds the library with the given name using the directory descriptors 3203 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3204 * 3205 * Returns a freshly-opened close-on-exec file descriptor for the library, 3206 * or -1 if the library cannot be found. 3207 */ 3208 static char * 3209 search_library_pathfds(const char *name, const char *path, int *fdp) 3210 { 3211 char *envcopy, *fdstr, *found, *last_token; 3212 size_t len; 3213 int dirfd, fd; 3214 3215 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3216 3217 /* Don't load from user-specified libdirs into setuid binaries. */ 3218 if (!trust) 3219 return (NULL); 3220 3221 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3222 if (path == NULL) 3223 return (NULL); 3224 3225 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3226 if (name[0] == '/') { 3227 dbg("Absolute path (%s) passed to %s", name, __func__); 3228 return (NULL); 3229 } 3230 3231 /* 3232 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3233 * copy of the path, as strtok_r rewrites separator tokens 3234 * with '\0'. 3235 */ 3236 found = NULL; 3237 envcopy = xstrdup(path); 3238 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3239 fdstr = strtok_r(NULL, ":", &last_token)) { 3240 dirfd = parse_integer(fdstr); 3241 if (dirfd < 0) { 3242 _rtld_error("failed to parse directory FD: '%s'", 3243 fdstr); 3244 break; 3245 } 3246 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3247 if (fd >= 0) { 3248 *fdp = fd; 3249 len = strlen(fdstr) + strlen(name) + 3; 3250 found = xmalloc(len); 3251 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3252 _rtld_error("error generating '%d/%s'", 3253 dirfd, name); 3254 rtld_die(); 3255 } 3256 dbg("open('%s') => %d", found, fd); 3257 break; 3258 } 3259 } 3260 free(envcopy); 3261 3262 return (found); 3263 } 3264 3265 3266 int 3267 dlclose(void *handle) 3268 { 3269 RtldLockState lockstate; 3270 int error; 3271 3272 wlock_acquire(rtld_bind_lock, &lockstate); 3273 error = dlclose_locked(handle, &lockstate); 3274 lock_release(rtld_bind_lock, &lockstate); 3275 return (error); 3276 } 3277 3278 static int 3279 dlclose_locked(void *handle, RtldLockState *lockstate) 3280 { 3281 Obj_Entry *root; 3282 3283 root = dlcheck(handle); 3284 if (root == NULL) 3285 return -1; 3286 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3287 root->path); 3288 3289 /* Unreference the object and its dependencies. */ 3290 root->dl_refcount--; 3291 3292 if (root->refcount == 1) { 3293 /* 3294 * The object will be no longer referenced, so we must unload it. 3295 * First, call the fini functions. 3296 */ 3297 objlist_call_fini(&list_fini, root, lockstate); 3298 3299 unref_dag(root); 3300 3301 /* Finish cleaning up the newly-unreferenced objects. */ 3302 GDB_STATE(RT_DELETE,&root->linkmap); 3303 unload_object(root, lockstate); 3304 GDB_STATE(RT_CONSISTENT,NULL); 3305 } else 3306 unref_dag(root); 3307 3308 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3309 return 0; 3310 } 3311 3312 char * 3313 dlerror(void) 3314 { 3315 char *msg = error_message; 3316 error_message = NULL; 3317 return msg; 3318 } 3319 3320 /* 3321 * This function is deprecated and has no effect. 3322 */ 3323 void 3324 dllockinit(void *context, 3325 void *(*_lock_create)(void *context) __unused, 3326 void (*_rlock_acquire)(void *lock) __unused, 3327 void (*_wlock_acquire)(void *lock) __unused, 3328 void (*_lock_release)(void *lock) __unused, 3329 void (*_lock_destroy)(void *lock) __unused, 3330 void (*context_destroy)(void *context)) 3331 { 3332 static void *cur_context; 3333 static void (*cur_context_destroy)(void *); 3334 3335 /* Just destroy the context from the previous call, if necessary. */ 3336 if (cur_context_destroy != NULL) 3337 cur_context_destroy(cur_context); 3338 cur_context = context; 3339 cur_context_destroy = context_destroy; 3340 } 3341 3342 void * 3343 dlopen(const char *name, int mode) 3344 { 3345 3346 return (rtld_dlopen(name, -1, mode)); 3347 } 3348 3349 void * 3350 fdlopen(int fd, int mode) 3351 { 3352 3353 return (rtld_dlopen(NULL, fd, mode)); 3354 } 3355 3356 static void * 3357 rtld_dlopen(const char *name, int fd, int mode) 3358 { 3359 RtldLockState lockstate; 3360 int lo_flags; 3361 3362 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3363 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3364 if (ld_tracing != NULL) { 3365 rlock_acquire(rtld_bind_lock, &lockstate); 3366 if (sigsetjmp(lockstate.env, 0) != 0) 3367 lock_upgrade(rtld_bind_lock, &lockstate); 3368 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3369 lock_release(rtld_bind_lock, &lockstate); 3370 } 3371 lo_flags = RTLD_LO_DLOPEN; 3372 if (mode & RTLD_NODELETE) 3373 lo_flags |= RTLD_LO_NODELETE; 3374 if (mode & RTLD_NOLOAD) 3375 lo_flags |= RTLD_LO_NOLOAD; 3376 if (mode & RTLD_DEEPBIND) 3377 lo_flags |= RTLD_LO_DEEPBIND; 3378 if (ld_tracing != NULL) 3379 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3380 3381 return (dlopen_object(name, fd, obj_main, lo_flags, 3382 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3383 } 3384 3385 static void 3386 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3387 { 3388 3389 obj->dl_refcount--; 3390 unref_dag(obj); 3391 if (obj->refcount == 0) 3392 unload_object(obj, lockstate); 3393 } 3394 3395 static Obj_Entry * 3396 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3397 int mode, RtldLockState *lockstate) 3398 { 3399 Obj_Entry *old_obj_tail; 3400 Obj_Entry *obj; 3401 Objlist initlist; 3402 RtldLockState mlockstate; 3403 int result; 3404 3405 objlist_init(&initlist); 3406 3407 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3408 wlock_acquire(rtld_bind_lock, &mlockstate); 3409 lockstate = &mlockstate; 3410 } 3411 GDB_STATE(RT_ADD,NULL); 3412 3413 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3414 obj = NULL; 3415 if (name == NULL && fd == -1) { 3416 obj = obj_main; 3417 obj->refcount++; 3418 } else { 3419 obj = load_object(name, fd, refobj, lo_flags); 3420 } 3421 3422 if (obj) { 3423 obj->dl_refcount++; 3424 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3425 objlist_push_tail(&list_global, obj); 3426 if (globallist_next(old_obj_tail) != NULL) { 3427 /* We loaded something new. */ 3428 assert(globallist_next(old_obj_tail) == obj); 3429 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3430 obj->symbolic = true; 3431 result = 0; 3432 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3433 obj->static_tls && !allocate_tls_offset(obj)) { 3434 _rtld_error("%s: No space available " 3435 "for static Thread Local Storage", obj->path); 3436 result = -1; 3437 } 3438 if (result != -1) 3439 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3440 RTLD_LO_EARLY | RTLD_LO_IGNSTLS)); 3441 init_dag(obj); 3442 ref_dag(obj); 3443 if (result != -1) 3444 result = rtld_verify_versions(&obj->dagmembers); 3445 if (result != -1 && ld_tracing) 3446 goto trace; 3447 if (result == -1 || relocate_object_dag(obj, 3448 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3449 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3450 lockstate) == -1) { 3451 dlopen_cleanup(obj, lockstate); 3452 obj = NULL; 3453 } else if (lo_flags & RTLD_LO_EARLY) { 3454 /* 3455 * Do not call the init functions for early loaded 3456 * filtees. The image is still not initialized enough 3457 * for them to work. 3458 * 3459 * Our object is found by the global object list and 3460 * will be ordered among all init calls done right 3461 * before transferring control to main. 3462 */ 3463 } else { 3464 /* Make list of init functions to call. */ 3465 initlist_add_objects(obj, obj, &initlist); 3466 } 3467 /* 3468 * Process all no_delete or global objects here, given 3469 * them own DAGs to prevent their dependencies from being 3470 * unloaded. This has to be done after we have loaded all 3471 * of the dependencies, so that we do not miss any. 3472 */ 3473 if (obj != NULL) 3474 process_z(obj); 3475 } else { 3476 /* 3477 * Bump the reference counts for objects on this DAG. If 3478 * this is the first dlopen() call for the object that was 3479 * already loaded as a dependency, initialize the dag 3480 * starting at it. 3481 */ 3482 init_dag(obj); 3483 ref_dag(obj); 3484 3485 if ((lo_flags & RTLD_LO_TRACE) != 0) 3486 goto trace; 3487 } 3488 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3489 obj->z_nodelete) && !obj->ref_nodel) { 3490 dbg("obj %s nodelete", obj->path); 3491 ref_dag(obj); 3492 obj->z_nodelete = obj->ref_nodel = true; 3493 } 3494 } 3495 3496 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3497 name); 3498 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3499 3500 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3501 map_stacks_exec(lockstate); 3502 if (obj != NULL) 3503 distribute_static_tls(&initlist, lockstate); 3504 } 3505 3506 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3507 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3508 lockstate) == -1) { 3509 objlist_clear(&initlist); 3510 dlopen_cleanup(obj, lockstate); 3511 if (lockstate == &mlockstate) 3512 lock_release(rtld_bind_lock, lockstate); 3513 return (NULL); 3514 } 3515 3516 if (!(lo_flags & RTLD_LO_EARLY)) { 3517 /* Call the init functions. */ 3518 objlist_call_init(&initlist, lockstate); 3519 } 3520 objlist_clear(&initlist); 3521 if (lockstate == &mlockstate) 3522 lock_release(rtld_bind_lock, lockstate); 3523 return obj; 3524 trace: 3525 trace_loaded_objects(obj); 3526 if (lockstate == &mlockstate) 3527 lock_release(rtld_bind_lock, lockstate); 3528 exit(0); 3529 } 3530 3531 static void * 3532 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3533 int flags) 3534 { 3535 DoneList donelist; 3536 const Obj_Entry *obj, *defobj; 3537 const Elf_Sym *def; 3538 SymLook req; 3539 RtldLockState lockstate; 3540 tls_index ti; 3541 void *sym; 3542 int res; 3543 3544 def = NULL; 3545 defobj = NULL; 3546 symlook_init(&req, name); 3547 req.ventry = ve; 3548 req.flags = flags | SYMLOOK_IN_PLT; 3549 req.lockstate = &lockstate; 3550 3551 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3552 rlock_acquire(rtld_bind_lock, &lockstate); 3553 if (sigsetjmp(lockstate.env, 0) != 0) 3554 lock_upgrade(rtld_bind_lock, &lockstate); 3555 if (handle == NULL || handle == RTLD_NEXT || 3556 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3557 3558 if ((obj = obj_from_addr(retaddr)) == NULL) { 3559 _rtld_error("Cannot determine caller's shared object"); 3560 lock_release(rtld_bind_lock, &lockstate); 3561 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3562 return NULL; 3563 } 3564 if (handle == NULL) { /* Just the caller's shared object. */ 3565 res = symlook_obj(&req, obj); 3566 if (res == 0) { 3567 def = req.sym_out; 3568 defobj = req.defobj_out; 3569 } 3570 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3571 handle == RTLD_SELF) { /* ... caller included */ 3572 if (handle == RTLD_NEXT) 3573 obj = globallist_next(obj); 3574 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3575 if (obj->marker) 3576 continue; 3577 res = symlook_obj(&req, obj); 3578 if (res == 0) { 3579 if (def == NULL || 3580 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3581 def = req.sym_out; 3582 defobj = req.defobj_out; 3583 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3584 break; 3585 } 3586 } 3587 } 3588 /* 3589 * Search the dynamic linker itself, and possibly resolve the 3590 * symbol from there. This is how the application links to 3591 * dynamic linker services such as dlopen. 3592 */ 3593 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3594 res = symlook_obj(&req, &obj_rtld); 3595 if (res == 0) { 3596 def = req.sym_out; 3597 defobj = req.defobj_out; 3598 } 3599 } 3600 } else { 3601 assert(handle == RTLD_DEFAULT); 3602 res = symlook_default(&req, obj); 3603 if (res == 0) { 3604 defobj = req.defobj_out; 3605 def = req.sym_out; 3606 } 3607 } 3608 } else { 3609 if ((obj = dlcheck(handle)) == NULL) { 3610 lock_release(rtld_bind_lock, &lockstate); 3611 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3612 return NULL; 3613 } 3614 3615 donelist_init(&donelist); 3616 if (obj->mainprog) { 3617 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3618 res = symlook_global(&req, &donelist); 3619 if (res == 0) { 3620 def = req.sym_out; 3621 defobj = req.defobj_out; 3622 } 3623 /* 3624 * Search the dynamic linker itself, and possibly resolve the 3625 * symbol from there. This is how the application links to 3626 * dynamic linker services such as dlopen. 3627 */ 3628 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3629 res = symlook_obj(&req, &obj_rtld); 3630 if (res == 0) { 3631 def = req.sym_out; 3632 defobj = req.defobj_out; 3633 } 3634 } 3635 } 3636 else { 3637 /* Search the whole DAG rooted at the given object. */ 3638 res = symlook_list(&req, &obj->dagmembers, &donelist); 3639 if (res == 0) { 3640 def = req.sym_out; 3641 defobj = req.defobj_out; 3642 } 3643 } 3644 } 3645 3646 if (def != NULL) { 3647 lock_release(rtld_bind_lock, &lockstate); 3648 3649 /* 3650 * The value required by the caller is derived from the value 3651 * of the symbol. this is simply the relocated value of the 3652 * symbol. 3653 */ 3654 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3655 sym = make_function_pointer(def, defobj); 3656 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3657 sym = rtld_resolve_ifunc(defobj, def); 3658 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3659 ti.ti_module = defobj->tlsindex; 3660 ti.ti_offset = def->st_value; 3661 sym = __tls_get_addr(&ti); 3662 } else 3663 sym = defobj->relocbase + def->st_value; 3664 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3665 return (sym); 3666 } 3667 3668 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3669 ve != NULL ? ve->name : ""); 3670 lock_release(rtld_bind_lock, &lockstate); 3671 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3672 return NULL; 3673 } 3674 3675 void * 3676 dlsym(void *handle, const char *name) 3677 { 3678 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3679 SYMLOOK_DLSYM); 3680 } 3681 3682 dlfunc_t 3683 dlfunc(void *handle, const char *name) 3684 { 3685 union { 3686 void *d; 3687 dlfunc_t f; 3688 } rv; 3689 3690 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3691 SYMLOOK_DLSYM); 3692 return (rv.f); 3693 } 3694 3695 void * 3696 dlvsym(void *handle, const char *name, const char *version) 3697 { 3698 Ver_Entry ventry; 3699 3700 ventry.name = version; 3701 ventry.file = NULL; 3702 ventry.hash = elf_hash(version); 3703 ventry.flags= 0; 3704 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3705 SYMLOOK_DLSYM); 3706 } 3707 3708 int 3709 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3710 { 3711 const Obj_Entry *obj; 3712 RtldLockState lockstate; 3713 3714 rlock_acquire(rtld_bind_lock, &lockstate); 3715 obj = obj_from_addr(addr); 3716 if (obj == NULL) { 3717 _rtld_error("No shared object contains address"); 3718 lock_release(rtld_bind_lock, &lockstate); 3719 return (0); 3720 } 3721 rtld_fill_dl_phdr_info(obj, phdr_info); 3722 lock_release(rtld_bind_lock, &lockstate); 3723 return (1); 3724 } 3725 3726 int 3727 dladdr(const void *addr, Dl_info *info) 3728 { 3729 const Obj_Entry *obj; 3730 const Elf_Sym *def; 3731 void *symbol_addr; 3732 unsigned long symoffset; 3733 RtldLockState lockstate; 3734 3735 rlock_acquire(rtld_bind_lock, &lockstate); 3736 obj = obj_from_addr(addr); 3737 if (obj == NULL) { 3738 _rtld_error("No shared object contains address"); 3739 lock_release(rtld_bind_lock, &lockstate); 3740 return 0; 3741 } 3742 info->dli_fname = obj->path; 3743 info->dli_fbase = obj->mapbase; 3744 info->dli_saddr = (void *)0; 3745 info->dli_sname = NULL; 3746 3747 /* 3748 * Walk the symbol list looking for the symbol whose address is 3749 * closest to the address sent in. 3750 */ 3751 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3752 def = obj->symtab + symoffset; 3753 3754 /* 3755 * For skip the symbol if st_shndx is either SHN_UNDEF or 3756 * SHN_COMMON. 3757 */ 3758 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3759 continue; 3760 3761 /* 3762 * If the symbol is greater than the specified address, or if it 3763 * is further away from addr than the current nearest symbol, 3764 * then reject it. 3765 */ 3766 symbol_addr = obj->relocbase + def->st_value; 3767 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3768 continue; 3769 3770 /* Update our idea of the nearest symbol. */ 3771 info->dli_sname = obj->strtab + def->st_name; 3772 info->dli_saddr = symbol_addr; 3773 3774 /* Exact match? */ 3775 if (info->dli_saddr == addr) 3776 break; 3777 } 3778 lock_release(rtld_bind_lock, &lockstate); 3779 return 1; 3780 } 3781 3782 int 3783 dlinfo(void *handle, int request, void *p) 3784 { 3785 const Obj_Entry *obj; 3786 RtldLockState lockstate; 3787 int error; 3788 3789 rlock_acquire(rtld_bind_lock, &lockstate); 3790 3791 if (handle == NULL || handle == RTLD_SELF) { 3792 void *retaddr; 3793 3794 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3795 if ((obj = obj_from_addr(retaddr)) == NULL) 3796 _rtld_error("Cannot determine caller's shared object"); 3797 } else 3798 obj = dlcheck(handle); 3799 3800 if (obj == NULL) { 3801 lock_release(rtld_bind_lock, &lockstate); 3802 return (-1); 3803 } 3804 3805 error = 0; 3806 switch (request) { 3807 case RTLD_DI_LINKMAP: 3808 *((struct link_map const **)p) = &obj->linkmap; 3809 break; 3810 case RTLD_DI_ORIGIN: 3811 error = rtld_dirname(obj->path, p); 3812 break; 3813 3814 case RTLD_DI_SERINFOSIZE: 3815 case RTLD_DI_SERINFO: 3816 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3817 break; 3818 3819 default: 3820 _rtld_error("Invalid request %d passed to dlinfo()", request); 3821 error = -1; 3822 } 3823 3824 lock_release(rtld_bind_lock, &lockstate); 3825 3826 return (error); 3827 } 3828 3829 static void 3830 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3831 { 3832 3833 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3834 phdr_info->dlpi_name = obj->path; 3835 phdr_info->dlpi_phdr = obj->phdr; 3836 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3837 phdr_info->dlpi_tls_modid = obj->tlsindex; 3838 phdr_info->dlpi_tls_data = obj->tlsinit; 3839 phdr_info->dlpi_adds = obj_loads; 3840 phdr_info->dlpi_subs = obj_loads - obj_count; 3841 } 3842 3843 int 3844 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3845 { 3846 struct dl_phdr_info phdr_info; 3847 Obj_Entry *obj, marker; 3848 RtldLockState bind_lockstate, phdr_lockstate; 3849 int error; 3850 3851 init_marker(&marker); 3852 error = 0; 3853 3854 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3855 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3856 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3857 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3858 rtld_fill_dl_phdr_info(obj, &phdr_info); 3859 hold_object(obj); 3860 lock_release(rtld_bind_lock, &bind_lockstate); 3861 3862 error = callback(&phdr_info, sizeof phdr_info, param); 3863 3864 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3865 unhold_object(obj); 3866 obj = globallist_next(&marker); 3867 TAILQ_REMOVE(&obj_list, &marker, next); 3868 if (error != 0) { 3869 lock_release(rtld_bind_lock, &bind_lockstate); 3870 lock_release(rtld_phdr_lock, &phdr_lockstate); 3871 return (error); 3872 } 3873 } 3874 3875 if (error == 0) { 3876 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3877 lock_release(rtld_bind_lock, &bind_lockstate); 3878 error = callback(&phdr_info, sizeof(phdr_info), param); 3879 } 3880 lock_release(rtld_phdr_lock, &phdr_lockstate); 3881 return (error); 3882 } 3883 3884 static void * 3885 fill_search_info(const char *dir, size_t dirlen, void *param) 3886 { 3887 struct fill_search_info_args *arg; 3888 3889 arg = param; 3890 3891 if (arg->request == RTLD_DI_SERINFOSIZE) { 3892 arg->serinfo->dls_cnt ++; 3893 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3894 } else { 3895 struct dl_serpath *s_entry; 3896 3897 s_entry = arg->serpath; 3898 s_entry->dls_name = arg->strspace; 3899 s_entry->dls_flags = arg->flags; 3900 3901 strncpy(arg->strspace, dir, dirlen); 3902 arg->strspace[dirlen] = '\0'; 3903 3904 arg->strspace += dirlen + 1; 3905 arg->serpath++; 3906 } 3907 3908 return (NULL); 3909 } 3910 3911 static int 3912 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3913 { 3914 struct dl_serinfo _info; 3915 struct fill_search_info_args args; 3916 3917 args.request = RTLD_DI_SERINFOSIZE; 3918 args.serinfo = &_info; 3919 3920 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3921 _info.dls_cnt = 0; 3922 3923 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3924 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3925 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3926 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3927 if (!obj->z_nodeflib) 3928 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3929 3930 3931 if (request == RTLD_DI_SERINFOSIZE) { 3932 info->dls_size = _info.dls_size; 3933 info->dls_cnt = _info.dls_cnt; 3934 return (0); 3935 } 3936 3937 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3938 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3939 return (-1); 3940 } 3941 3942 args.request = RTLD_DI_SERINFO; 3943 args.serinfo = info; 3944 args.serpath = &info->dls_serpath[0]; 3945 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3946 3947 args.flags = LA_SER_RUNPATH; 3948 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3949 return (-1); 3950 3951 args.flags = LA_SER_LIBPATH; 3952 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3953 return (-1); 3954 3955 args.flags = LA_SER_RUNPATH; 3956 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3957 return (-1); 3958 3959 args.flags = LA_SER_CONFIG; 3960 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3961 != NULL) 3962 return (-1); 3963 3964 args.flags = LA_SER_DEFAULT; 3965 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3966 fill_search_info, NULL, &args) != NULL) 3967 return (-1); 3968 return (0); 3969 } 3970 3971 static int 3972 rtld_dirname(const char *path, char *bname) 3973 { 3974 const char *endp; 3975 3976 /* Empty or NULL string gets treated as "." */ 3977 if (path == NULL || *path == '\0') { 3978 bname[0] = '.'; 3979 bname[1] = '\0'; 3980 return (0); 3981 } 3982 3983 /* Strip trailing slashes */ 3984 endp = path + strlen(path) - 1; 3985 while (endp > path && *endp == '/') 3986 endp--; 3987 3988 /* Find the start of the dir */ 3989 while (endp > path && *endp != '/') 3990 endp--; 3991 3992 /* Either the dir is "/" or there are no slashes */ 3993 if (endp == path) { 3994 bname[0] = *endp == '/' ? '/' : '.'; 3995 bname[1] = '\0'; 3996 return (0); 3997 } else { 3998 do { 3999 endp--; 4000 } while (endp > path && *endp == '/'); 4001 } 4002 4003 if (endp - path + 2 > PATH_MAX) 4004 { 4005 _rtld_error("Filename is too long: %s", path); 4006 return(-1); 4007 } 4008 4009 strncpy(bname, path, endp - path + 1); 4010 bname[endp - path + 1] = '\0'; 4011 return (0); 4012 } 4013 4014 static int 4015 rtld_dirname_abs(const char *path, char *base) 4016 { 4017 char *last; 4018 4019 if (realpath(path, base) == NULL) { 4020 _rtld_error("realpath \"%s\" failed (%s)", path, 4021 rtld_strerror(errno)); 4022 return (-1); 4023 } 4024 dbg("%s -> %s", path, base); 4025 last = strrchr(base, '/'); 4026 if (last == NULL) { 4027 _rtld_error("non-abs result from realpath \"%s\"", path); 4028 return (-1); 4029 } 4030 if (last != base) 4031 *last = '\0'; 4032 return (0); 4033 } 4034 4035 static void 4036 linkmap_add(Obj_Entry *obj) 4037 { 4038 struct link_map *l, *prev; 4039 4040 l = &obj->linkmap; 4041 l->l_name = obj->path; 4042 l->l_base = obj->mapbase; 4043 l->l_ld = obj->dynamic; 4044 l->l_addr = obj->relocbase; 4045 4046 if (r_debug.r_map == NULL) { 4047 r_debug.r_map = l; 4048 return; 4049 } 4050 4051 /* 4052 * Scan to the end of the list, but not past the entry for the 4053 * dynamic linker, which we want to keep at the very end. 4054 */ 4055 for (prev = r_debug.r_map; 4056 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4057 prev = prev->l_next) 4058 ; 4059 4060 /* Link in the new entry. */ 4061 l->l_prev = prev; 4062 l->l_next = prev->l_next; 4063 if (l->l_next != NULL) 4064 l->l_next->l_prev = l; 4065 prev->l_next = l; 4066 } 4067 4068 static void 4069 linkmap_delete(Obj_Entry *obj) 4070 { 4071 struct link_map *l; 4072 4073 l = &obj->linkmap; 4074 if (l->l_prev == NULL) { 4075 if ((r_debug.r_map = l->l_next) != NULL) 4076 l->l_next->l_prev = NULL; 4077 return; 4078 } 4079 4080 if ((l->l_prev->l_next = l->l_next) != NULL) 4081 l->l_next->l_prev = l->l_prev; 4082 } 4083 4084 /* 4085 * Function for the debugger to set a breakpoint on to gain control. 4086 * 4087 * The two parameters allow the debugger to easily find and determine 4088 * what the runtime loader is doing and to whom it is doing it. 4089 * 4090 * When the loadhook trap is hit (r_debug_state, set at program 4091 * initialization), the arguments can be found on the stack: 4092 * 4093 * +8 struct link_map *m 4094 * +4 struct r_debug *rd 4095 * +0 RetAddr 4096 */ 4097 void 4098 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4099 { 4100 /* 4101 * The following is a hack to force the compiler to emit calls to 4102 * this function, even when optimizing. If the function is empty, 4103 * the compiler is not obliged to emit any code for calls to it, 4104 * even when marked __noinline. However, gdb depends on those 4105 * calls being made. 4106 */ 4107 __compiler_membar(); 4108 } 4109 4110 /* 4111 * A function called after init routines have completed. This can be used to 4112 * break before a program's entry routine is called, and can be used when 4113 * main is not available in the symbol table. 4114 */ 4115 void 4116 _r_debug_postinit(struct link_map *m __unused) 4117 { 4118 4119 /* See r_debug_state(). */ 4120 __compiler_membar(); 4121 } 4122 4123 static void 4124 release_object(Obj_Entry *obj) 4125 { 4126 4127 if (obj->holdcount > 0) { 4128 obj->unholdfree = true; 4129 return; 4130 } 4131 munmap(obj->mapbase, obj->mapsize); 4132 linkmap_delete(obj); 4133 obj_free(obj); 4134 } 4135 4136 /* 4137 * Get address of the pointer variable in the main program. 4138 * Prefer non-weak symbol over the weak one. 4139 */ 4140 static const void ** 4141 get_program_var_addr(const char *name, RtldLockState *lockstate) 4142 { 4143 SymLook req; 4144 DoneList donelist; 4145 4146 symlook_init(&req, name); 4147 req.lockstate = lockstate; 4148 donelist_init(&donelist); 4149 if (symlook_global(&req, &donelist) != 0) 4150 return (NULL); 4151 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4152 return ((const void **)make_function_pointer(req.sym_out, 4153 req.defobj_out)); 4154 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4155 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4156 else 4157 return ((const void **)(req.defobj_out->relocbase + 4158 req.sym_out->st_value)); 4159 } 4160 4161 /* 4162 * Set a pointer variable in the main program to the given value. This 4163 * is used to set key variables such as "environ" before any of the 4164 * init functions are called. 4165 */ 4166 static void 4167 set_program_var(const char *name, const void *value) 4168 { 4169 const void **addr; 4170 4171 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4172 dbg("\"%s\": *%p <-- %p", name, addr, value); 4173 *addr = value; 4174 } 4175 } 4176 4177 /* 4178 * Search the global objects, including dependencies and main object, 4179 * for the given symbol. 4180 */ 4181 static int 4182 symlook_global(SymLook *req, DoneList *donelist) 4183 { 4184 SymLook req1; 4185 const Objlist_Entry *elm; 4186 int res; 4187 4188 symlook_init_from_req(&req1, req); 4189 4190 /* Search all objects loaded at program start up. */ 4191 if (req->defobj_out == NULL || 4192 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4193 res = symlook_list(&req1, &list_main, donelist); 4194 if (res == 0 && (req->defobj_out == NULL || 4195 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4196 req->sym_out = req1.sym_out; 4197 req->defobj_out = req1.defobj_out; 4198 assert(req->defobj_out != NULL); 4199 } 4200 } 4201 4202 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4203 STAILQ_FOREACH(elm, &list_global, link) { 4204 if (req->defobj_out != NULL && 4205 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4206 break; 4207 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4208 if (res == 0 && (req->defobj_out == NULL || 4209 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4210 req->sym_out = req1.sym_out; 4211 req->defobj_out = req1.defobj_out; 4212 assert(req->defobj_out != NULL); 4213 } 4214 } 4215 4216 return (req->sym_out != NULL ? 0 : ESRCH); 4217 } 4218 4219 /* 4220 * Given a symbol name in a referencing object, find the corresponding 4221 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4222 * no definition was found. Returns a pointer to the Obj_Entry of the 4223 * defining object via the reference parameter DEFOBJ_OUT. 4224 */ 4225 static int 4226 symlook_default(SymLook *req, const Obj_Entry *refobj) 4227 { 4228 DoneList donelist; 4229 const Objlist_Entry *elm; 4230 SymLook req1; 4231 int res; 4232 4233 donelist_init(&donelist); 4234 symlook_init_from_req(&req1, req); 4235 4236 /* 4237 * Look first in the referencing object if linked symbolically, 4238 * and similarly handle protected symbols. 4239 */ 4240 res = symlook_obj(&req1, refobj); 4241 if (res == 0 && (refobj->symbolic || 4242 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4243 req->sym_out = req1.sym_out; 4244 req->defobj_out = req1.defobj_out; 4245 assert(req->defobj_out != NULL); 4246 } 4247 if (refobj->symbolic || req->defobj_out != NULL) 4248 donelist_check(&donelist, refobj); 4249 4250 symlook_global(req, &donelist); 4251 4252 /* Search all dlopened DAGs containing the referencing object. */ 4253 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4254 if (req->sym_out != NULL && 4255 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4256 break; 4257 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4258 if (res == 0 && (req->sym_out == NULL || 4259 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4260 req->sym_out = req1.sym_out; 4261 req->defobj_out = req1.defobj_out; 4262 assert(req->defobj_out != NULL); 4263 } 4264 } 4265 4266 /* 4267 * Search the dynamic linker itself, and possibly resolve the 4268 * symbol from there. This is how the application links to 4269 * dynamic linker services such as dlopen. 4270 */ 4271 if (req->sym_out == NULL || 4272 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4273 res = symlook_obj(&req1, &obj_rtld); 4274 if (res == 0) { 4275 req->sym_out = req1.sym_out; 4276 req->defobj_out = req1.defobj_out; 4277 assert(req->defobj_out != NULL); 4278 } 4279 } 4280 4281 return (req->sym_out != NULL ? 0 : ESRCH); 4282 } 4283 4284 static int 4285 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4286 { 4287 const Elf_Sym *def; 4288 const Obj_Entry *defobj; 4289 const Objlist_Entry *elm; 4290 SymLook req1; 4291 int res; 4292 4293 def = NULL; 4294 defobj = NULL; 4295 STAILQ_FOREACH(elm, objlist, link) { 4296 if (donelist_check(dlp, elm->obj)) 4297 continue; 4298 symlook_init_from_req(&req1, req); 4299 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4300 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4301 def = req1.sym_out; 4302 defobj = req1.defobj_out; 4303 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4304 break; 4305 } 4306 } 4307 } 4308 if (def != NULL) { 4309 req->sym_out = def; 4310 req->defobj_out = defobj; 4311 return (0); 4312 } 4313 return (ESRCH); 4314 } 4315 4316 /* 4317 * Search the chain of DAGS cointed to by the given Needed_Entry 4318 * for a symbol of the given name. Each DAG is scanned completely 4319 * before advancing to the next one. Returns a pointer to the symbol, 4320 * or NULL if no definition was found. 4321 */ 4322 static int 4323 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4324 { 4325 const Elf_Sym *def; 4326 const Needed_Entry *n; 4327 const Obj_Entry *defobj; 4328 SymLook req1; 4329 int res; 4330 4331 def = NULL; 4332 defobj = NULL; 4333 symlook_init_from_req(&req1, req); 4334 for (n = needed; n != NULL; n = n->next) { 4335 if (n->obj == NULL || 4336 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4337 continue; 4338 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4339 def = req1.sym_out; 4340 defobj = req1.defobj_out; 4341 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4342 break; 4343 } 4344 } 4345 if (def != NULL) { 4346 req->sym_out = def; 4347 req->defobj_out = defobj; 4348 return (0); 4349 } 4350 return (ESRCH); 4351 } 4352 4353 /* 4354 * Search the symbol table of a single shared object for a symbol of 4355 * the given name and version, if requested. Returns a pointer to the 4356 * symbol, or NULL if no definition was found. If the object is 4357 * filter, return filtered symbol from filtee. 4358 * 4359 * The symbol's hash value is passed in for efficiency reasons; that 4360 * eliminates many recomputations of the hash value. 4361 */ 4362 int 4363 symlook_obj(SymLook *req, const Obj_Entry *obj) 4364 { 4365 DoneList donelist; 4366 SymLook req1; 4367 int flags, res, mres; 4368 4369 /* 4370 * If there is at least one valid hash at this point, we prefer to 4371 * use the faster GNU version if available. 4372 */ 4373 if (obj->valid_hash_gnu) 4374 mres = symlook_obj1_gnu(req, obj); 4375 else if (obj->valid_hash_sysv) 4376 mres = symlook_obj1_sysv(req, obj); 4377 else 4378 return (EINVAL); 4379 4380 if (mres == 0) { 4381 if (obj->needed_filtees != NULL) { 4382 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4383 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4384 donelist_init(&donelist); 4385 symlook_init_from_req(&req1, req); 4386 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4387 if (res == 0) { 4388 req->sym_out = req1.sym_out; 4389 req->defobj_out = req1.defobj_out; 4390 } 4391 return (res); 4392 } 4393 if (obj->needed_aux_filtees != NULL) { 4394 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4395 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4396 donelist_init(&donelist); 4397 symlook_init_from_req(&req1, req); 4398 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4399 if (res == 0) { 4400 req->sym_out = req1.sym_out; 4401 req->defobj_out = req1.defobj_out; 4402 return (res); 4403 } 4404 } 4405 } 4406 return (mres); 4407 } 4408 4409 /* Symbol match routine common to both hash functions */ 4410 static bool 4411 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4412 const unsigned long symnum) 4413 { 4414 Elf_Versym verndx; 4415 const Elf_Sym *symp; 4416 const char *strp; 4417 4418 symp = obj->symtab + symnum; 4419 strp = obj->strtab + symp->st_name; 4420 4421 switch (ELF_ST_TYPE(symp->st_info)) { 4422 case STT_FUNC: 4423 case STT_NOTYPE: 4424 case STT_OBJECT: 4425 case STT_COMMON: 4426 case STT_GNU_IFUNC: 4427 if (symp->st_value == 0) 4428 return (false); 4429 /* fallthrough */ 4430 case STT_TLS: 4431 if (symp->st_shndx != SHN_UNDEF) 4432 break; 4433 #ifndef __mips__ 4434 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4435 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4436 break; 4437 #endif 4438 /* fallthrough */ 4439 default: 4440 return (false); 4441 } 4442 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4443 return (false); 4444 4445 if (req->ventry == NULL) { 4446 if (obj->versyms != NULL) { 4447 verndx = VER_NDX(obj->versyms[symnum]); 4448 if (verndx > obj->vernum) { 4449 _rtld_error( 4450 "%s: symbol %s references wrong version %d", 4451 obj->path, obj->strtab + symnum, verndx); 4452 return (false); 4453 } 4454 /* 4455 * If we are not called from dlsym (i.e. this 4456 * is a normal relocation from unversioned 4457 * binary), accept the symbol immediately if 4458 * it happens to have first version after this 4459 * shared object became versioned. Otherwise, 4460 * if symbol is versioned and not hidden, 4461 * remember it. If it is the only symbol with 4462 * this name exported by the shared object, it 4463 * will be returned as a match by the calling 4464 * function. If symbol is global (verndx < 2) 4465 * accept it unconditionally. 4466 */ 4467 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4468 verndx == VER_NDX_GIVEN) { 4469 result->sym_out = symp; 4470 return (true); 4471 } 4472 else if (verndx >= VER_NDX_GIVEN) { 4473 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4474 == 0) { 4475 if (result->vsymp == NULL) 4476 result->vsymp = symp; 4477 result->vcount++; 4478 } 4479 return (false); 4480 } 4481 } 4482 result->sym_out = symp; 4483 return (true); 4484 } 4485 if (obj->versyms == NULL) { 4486 if (object_match_name(obj, req->ventry->name)) { 4487 _rtld_error("%s: object %s should provide version %s " 4488 "for symbol %s", obj_rtld.path, obj->path, 4489 req->ventry->name, obj->strtab + symnum); 4490 return (false); 4491 } 4492 } else { 4493 verndx = VER_NDX(obj->versyms[symnum]); 4494 if (verndx > obj->vernum) { 4495 _rtld_error("%s: symbol %s references wrong version %d", 4496 obj->path, obj->strtab + symnum, verndx); 4497 return (false); 4498 } 4499 if (obj->vertab[verndx].hash != req->ventry->hash || 4500 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4501 /* 4502 * Version does not match. Look if this is a 4503 * global symbol and if it is not hidden. If 4504 * global symbol (verndx < 2) is available, 4505 * use it. Do not return symbol if we are 4506 * called by dlvsym, because dlvsym looks for 4507 * a specific version and default one is not 4508 * what dlvsym wants. 4509 */ 4510 if ((req->flags & SYMLOOK_DLSYM) || 4511 (verndx >= VER_NDX_GIVEN) || 4512 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4513 return (false); 4514 } 4515 } 4516 result->sym_out = symp; 4517 return (true); 4518 } 4519 4520 /* 4521 * Search for symbol using SysV hash function. 4522 * obj->buckets is known not to be NULL at this point; the test for this was 4523 * performed with the obj->valid_hash_sysv assignment. 4524 */ 4525 static int 4526 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4527 { 4528 unsigned long symnum; 4529 Sym_Match_Result matchres; 4530 4531 matchres.sym_out = NULL; 4532 matchres.vsymp = NULL; 4533 matchres.vcount = 0; 4534 4535 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4536 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4537 if (symnum >= obj->nchains) 4538 return (ESRCH); /* Bad object */ 4539 4540 if (matched_symbol(req, obj, &matchres, symnum)) { 4541 req->sym_out = matchres.sym_out; 4542 req->defobj_out = obj; 4543 return (0); 4544 } 4545 } 4546 if (matchres.vcount == 1) { 4547 req->sym_out = matchres.vsymp; 4548 req->defobj_out = obj; 4549 return (0); 4550 } 4551 return (ESRCH); 4552 } 4553 4554 /* Search for symbol using GNU hash function */ 4555 static int 4556 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4557 { 4558 Elf_Addr bloom_word; 4559 const Elf32_Word *hashval; 4560 Elf32_Word bucket; 4561 Sym_Match_Result matchres; 4562 unsigned int h1, h2; 4563 unsigned long symnum; 4564 4565 matchres.sym_out = NULL; 4566 matchres.vsymp = NULL; 4567 matchres.vcount = 0; 4568 4569 /* Pick right bitmask word from Bloom filter array */ 4570 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4571 obj->maskwords_bm_gnu]; 4572 4573 /* Calculate modulus word size of gnu hash and its derivative */ 4574 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4575 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4576 4577 /* Filter out the "definitely not in set" queries */ 4578 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4579 return (ESRCH); 4580 4581 /* Locate hash chain and corresponding value element*/ 4582 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4583 if (bucket == 0) 4584 return (ESRCH); 4585 hashval = &obj->chain_zero_gnu[bucket]; 4586 do { 4587 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4588 symnum = hashval - obj->chain_zero_gnu; 4589 if (matched_symbol(req, obj, &matchres, symnum)) { 4590 req->sym_out = matchres.sym_out; 4591 req->defobj_out = obj; 4592 return (0); 4593 } 4594 } 4595 } while ((*hashval++ & 1) == 0); 4596 if (matchres.vcount == 1) { 4597 req->sym_out = matchres.vsymp; 4598 req->defobj_out = obj; 4599 return (0); 4600 } 4601 return (ESRCH); 4602 } 4603 4604 static void 4605 trace_loaded_objects(Obj_Entry *obj) 4606 { 4607 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4608 int c; 4609 4610 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4611 main_local = ""; 4612 4613 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4614 fmt1 = "\t%o => %p (%x)\n"; 4615 4616 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4617 fmt2 = "\t%o (%x)\n"; 4618 4619 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4620 4621 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4622 Needed_Entry *needed; 4623 const char *name, *path; 4624 bool is_lib; 4625 4626 if (obj->marker) 4627 continue; 4628 if (list_containers && obj->needed != NULL) 4629 rtld_printf("%s:\n", obj->path); 4630 for (needed = obj->needed; needed; needed = needed->next) { 4631 if (needed->obj != NULL) { 4632 if (needed->obj->traced && !list_containers) 4633 continue; 4634 needed->obj->traced = true; 4635 path = needed->obj->path; 4636 } else 4637 path = "not found"; 4638 4639 name = obj->strtab + needed->name; 4640 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4641 4642 fmt = is_lib ? fmt1 : fmt2; 4643 while ((c = *fmt++) != '\0') { 4644 switch (c) { 4645 default: 4646 rtld_putchar(c); 4647 continue; 4648 case '\\': 4649 switch (c = *fmt) { 4650 case '\0': 4651 continue; 4652 case 'n': 4653 rtld_putchar('\n'); 4654 break; 4655 case 't': 4656 rtld_putchar('\t'); 4657 break; 4658 } 4659 break; 4660 case '%': 4661 switch (c = *fmt) { 4662 case '\0': 4663 continue; 4664 case '%': 4665 default: 4666 rtld_putchar(c); 4667 break; 4668 case 'A': 4669 rtld_putstr(main_local); 4670 break; 4671 case 'a': 4672 rtld_putstr(obj_main->path); 4673 break; 4674 case 'o': 4675 rtld_putstr(name); 4676 break; 4677 #if 0 4678 case 'm': 4679 rtld_printf("%d", sodp->sod_major); 4680 break; 4681 case 'n': 4682 rtld_printf("%d", sodp->sod_minor); 4683 break; 4684 #endif 4685 case 'p': 4686 rtld_putstr(path); 4687 break; 4688 case 'x': 4689 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4690 0); 4691 break; 4692 } 4693 break; 4694 } 4695 ++fmt; 4696 } 4697 } 4698 } 4699 } 4700 4701 /* 4702 * Unload a dlopened object and its dependencies from memory and from 4703 * our data structures. It is assumed that the DAG rooted in the 4704 * object has already been unreferenced, and that the object has a 4705 * reference count of 0. 4706 */ 4707 static void 4708 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4709 { 4710 Obj_Entry marker, *obj, *next; 4711 4712 assert(root->refcount == 0); 4713 4714 /* 4715 * Pass over the DAG removing unreferenced objects from 4716 * appropriate lists. 4717 */ 4718 unlink_object(root); 4719 4720 /* Unmap all objects that are no longer referenced. */ 4721 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4722 next = TAILQ_NEXT(obj, next); 4723 if (obj->marker || obj->refcount != 0) 4724 continue; 4725 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4726 obj->mapsize, 0, obj->path); 4727 dbg("unloading \"%s\"", obj->path); 4728 /* 4729 * Unlink the object now to prevent new references from 4730 * being acquired while the bind lock is dropped in 4731 * recursive dlclose() invocations. 4732 */ 4733 TAILQ_REMOVE(&obj_list, obj, next); 4734 obj_count--; 4735 4736 if (obj->filtees_loaded) { 4737 if (next != NULL) { 4738 init_marker(&marker); 4739 TAILQ_INSERT_BEFORE(next, &marker, next); 4740 unload_filtees(obj, lockstate); 4741 next = TAILQ_NEXT(&marker, next); 4742 TAILQ_REMOVE(&obj_list, &marker, next); 4743 } else 4744 unload_filtees(obj, lockstate); 4745 } 4746 release_object(obj); 4747 } 4748 } 4749 4750 static void 4751 unlink_object(Obj_Entry *root) 4752 { 4753 Objlist_Entry *elm; 4754 4755 if (root->refcount == 0) { 4756 /* Remove the object from the RTLD_GLOBAL list. */ 4757 objlist_remove(&list_global, root); 4758 4759 /* Remove the object from all objects' DAG lists. */ 4760 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4761 objlist_remove(&elm->obj->dldags, root); 4762 if (elm->obj != root) 4763 unlink_object(elm->obj); 4764 } 4765 } 4766 } 4767 4768 static void 4769 ref_dag(Obj_Entry *root) 4770 { 4771 Objlist_Entry *elm; 4772 4773 assert(root->dag_inited); 4774 STAILQ_FOREACH(elm, &root->dagmembers, link) 4775 elm->obj->refcount++; 4776 } 4777 4778 static void 4779 unref_dag(Obj_Entry *root) 4780 { 4781 Objlist_Entry *elm; 4782 4783 assert(root->dag_inited); 4784 STAILQ_FOREACH(elm, &root->dagmembers, link) 4785 elm->obj->refcount--; 4786 } 4787 4788 /* 4789 * Common code for MD __tls_get_addr(). 4790 */ 4791 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4792 static void * 4793 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4794 { 4795 Elf_Addr *newdtv, *dtv; 4796 RtldLockState lockstate; 4797 int to_copy; 4798 4799 dtv = *dtvp; 4800 /* Check dtv generation in case new modules have arrived */ 4801 if (dtv[0] != tls_dtv_generation) { 4802 wlock_acquire(rtld_bind_lock, &lockstate); 4803 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4804 to_copy = dtv[1]; 4805 if (to_copy > tls_max_index) 4806 to_copy = tls_max_index; 4807 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4808 newdtv[0] = tls_dtv_generation; 4809 newdtv[1] = tls_max_index; 4810 free(dtv); 4811 lock_release(rtld_bind_lock, &lockstate); 4812 dtv = *dtvp = newdtv; 4813 } 4814 4815 /* Dynamically allocate module TLS if necessary */ 4816 if (dtv[index + 1] == 0) { 4817 /* Signal safe, wlock will block out signals. */ 4818 wlock_acquire(rtld_bind_lock, &lockstate); 4819 if (!dtv[index + 1]) 4820 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4821 lock_release(rtld_bind_lock, &lockstate); 4822 } 4823 return ((void *)(dtv[index + 1] + offset)); 4824 } 4825 4826 void * 4827 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4828 { 4829 Elf_Addr *dtv; 4830 4831 dtv = *dtvp; 4832 /* Check dtv generation in case new modules have arrived */ 4833 if (__predict_true(dtv[0] == tls_dtv_generation && 4834 dtv[index + 1] != 0)) 4835 return ((void *)(dtv[index + 1] + offset)); 4836 return (tls_get_addr_slow(dtvp, index, offset)); 4837 } 4838 4839 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4840 defined(__powerpc__) || defined(__riscv) 4841 4842 /* 4843 * Return pointer to allocated TLS block 4844 */ 4845 static void * 4846 get_tls_block_ptr(void *tcb, size_t tcbsize) 4847 { 4848 size_t extra_size, post_size, pre_size, tls_block_size; 4849 size_t tls_init_align; 4850 4851 tls_init_align = MAX(obj_main->tlsalign, 1); 4852 4853 /* Compute fragments sizes. */ 4854 extra_size = tcbsize - TLS_TCB_SIZE; 4855 post_size = calculate_tls_post_size(tls_init_align); 4856 tls_block_size = tcbsize + post_size; 4857 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4858 4859 return ((char *)tcb - pre_size - extra_size); 4860 } 4861 4862 /* 4863 * Allocate Static TLS using the Variant I method. 4864 * 4865 * For details on the layout, see lib/libc/gen/tls.c. 4866 * 4867 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4868 * it is based on tls_last_offset, and TLS offsets here are really TCB 4869 * offsets, whereas libc's tls_static_space is just the executable's static 4870 * TLS segment. 4871 */ 4872 void * 4873 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4874 { 4875 Obj_Entry *obj; 4876 char *tls_block; 4877 Elf_Addr *dtv, **tcb; 4878 Elf_Addr addr; 4879 Elf_Addr i; 4880 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4881 size_t tls_init_align, tls_init_offset; 4882 4883 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4884 return (oldtcb); 4885 4886 assert(tcbsize >= TLS_TCB_SIZE); 4887 maxalign = MAX(tcbalign, tls_static_max_align); 4888 tls_init_align = MAX(obj_main->tlsalign, 1); 4889 4890 /* Compute fragmets sizes. */ 4891 extra_size = tcbsize - TLS_TCB_SIZE; 4892 post_size = calculate_tls_post_size(tls_init_align); 4893 tls_block_size = tcbsize + post_size; 4894 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4895 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4896 4897 /* Allocate whole TLS block */ 4898 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4899 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4900 4901 if (oldtcb != NULL) { 4902 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4903 tls_static_space); 4904 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4905 4906 /* Adjust the DTV. */ 4907 dtv = tcb[0]; 4908 for (i = 0; i < dtv[1]; i++) { 4909 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4910 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4911 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4912 } 4913 } 4914 } else { 4915 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4916 tcb[0] = dtv; 4917 dtv[0] = tls_dtv_generation; 4918 dtv[1] = tls_max_index; 4919 4920 for (obj = globallist_curr(objs); obj != NULL; 4921 obj = globallist_next(obj)) { 4922 if (obj->tlsoffset == 0) 4923 continue; 4924 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4925 addr = (Elf_Addr)tcb + obj->tlsoffset; 4926 if (tls_init_offset > 0) 4927 memset((void *)addr, 0, tls_init_offset); 4928 if (obj->tlsinitsize > 0) { 4929 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4930 obj->tlsinitsize); 4931 } 4932 if (obj->tlssize > obj->tlsinitsize) { 4933 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4934 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4935 } 4936 dtv[obj->tlsindex + 1] = addr; 4937 } 4938 } 4939 4940 return (tcb); 4941 } 4942 4943 void 4944 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4945 { 4946 Elf_Addr *dtv; 4947 Elf_Addr tlsstart, tlsend; 4948 size_t post_size; 4949 size_t dtvsize, i, tls_init_align; 4950 4951 assert(tcbsize >= TLS_TCB_SIZE); 4952 tls_init_align = MAX(obj_main->tlsalign, 1); 4953 4954 /* Compute fragments sizes. */ 4955 post_size = calculate_tls_post_size(tls_init_align); 4956 4957 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4958 tlsend = (Elf_Addr)tcb + tls_static_space; 4959 4960 dtv = *(Elf_Addr **)tcb; 4961 dtvsize = dtv[1]; 4962 for (i = 0; i < dtvsize; i++) { 4963 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4964 free((void*)dtv[i+2]); 4965 } 4966 } 4967 free(dtv); 4968 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4969 } 4970 4971 #endif 4972 4973 #if defined(__i386__) || defined(__amd64__) 4974 4975 /* 4976 * Allocate Static TLS using the Variant II method. 4977 */ 4978 void * 4979 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4980 { 4981 Obj_Entry *obj; 4982 size_t size, ralign; 4983 char *tls; 4984 Elf_Addr *dtv, *olddtv; 4985 Elf_Addr segbase, oldsegbase, addr; 4986 size_t i; 4987 4988 ralign = tcbalign; 4989 if (tls_static_max_align > ralign) 4990 ralign = tls_static_max_align; 4991 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 4992 4993 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4994 tls = malloc_aligned(size, ralign, 0 /* XXX */); 4995 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4996 4997 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 4998 ((Elf_Addr*)segbase)[0] = segbase; 4999 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5000 5001 dtv[0] = tls_dtv_generation; 5002 dtv[1] = tls_max_index; 5003 5004 if (oldtls) { 5005 /* 5006 * Copy the static TLS block over whole. 5007 */ 5008 oldsegbase = (Elf_Addr) oldtls; 5009 memcpy((void *)(segbase - tls_static_space), 5010 (const void *)(oldsegbase - tls_static_space), 5011 tls_static_space); 5012 5013 /* 5014 * If any dynamic TLS blocks have been created tls_get_addr(), 5015 * move them over. 5016 */ 5017 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5018 for (i = 0; i < olddtv[1]; i++) { 5019 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5020 dtv[i+2] = olddtv[i+2]; 5021 olddtv[i+2] = 0; 5022 } 5023 } 5024 5025 /* 5026 * We assume that this block was the one we created with 5027 * allocate_initial_tls(). 5028 */ 5029 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5030 } else { 5031 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5032 if (obj->marker || obj->tlsoffset == 0) 5033 continue; 5034 addr = segbase - obj->tlsoffset; 5035 memset((void*)(addr + obj->tlsinitsize), 5036 0, obj->tlssize - obj->tlsinitsize); 5037 if (obj->tlsinit) { 5038 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5039 obj->static_tls_copied = true; 5040 } 5041 dtv[obj->tlsindex + 1] = addr; 5042 } 5043 } 5044 5045 return (void*) segbase; 5046 } 5047 5048 void 5049 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5050 { 5051 Elf_Addr* dtv; 5052 size_t size, ralign; 5053 int dtvsize, i; 5054 Elf_Addr tlsstart, tlsend; 5055 5056 /* 5057 * Figure out the size of the initial TLS block so that we can 5058 * find stuff which ___tls_get_addr() allocated dynamically. 5059 */ 5060 ralign = tcbalign; 5061 if (tls_static_max_align > ralign) 5062 ralign = tls_static_max_align; 5063 size = roundup(tls_static_space, ralign); 5064 5065 dtv = ((Elf_Addr**)tls)[1]; 5066 dtvsize = dtv[1]; 5067 tlsend = (Elf_Addr) tls; 5068 tlsstart = tlsend - size; 5069 for (i = 0; i < dtvsize; i++) { 5070 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5071 free_aligned((void *)dtv[i + 2]); 5072 } 5073 } 5074 5075 free_aligned((void *)tlsstart); 5076 free((void*) dtv); 5077 } 5078 5079 #endif 5080 5081 /* 5082 * Allocate TLS block for module with given index. 5083 */ 5084 void * 5085 allocate_module_tls(int index) 5086 { 5087 Obj_Entry *obj; 5088 char *p; 5089 5090 TAILQ_FOREACH(obj, &obj_list, next) { 5091 if (obj->marker) 5092 continue; 5093 if (obj->tlsindex == index) 5094 break; 5095 } 5096 if (obj == NULL) { 5097 _rtld_error("Can't find module with TLS index %d", index); 5098 rtld_die(); 5099 } 5100 5101 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5102 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5103 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5104 return (p); 5105 } 5106 5107 bool 5108 allocate_tls_offset(Obj_Entry *obj) 5109 { 5110 size_t off; 5111 5112 if (obj->tls_done) 5113 return true; 5114 5115 if (obj->tlssize == 0) { 5116 obj->tls_done = true; 5117 return true; 5118 } 5119 5120 if (tls_last_offset == 0) 5121 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5122 obj->tlspoffset); 5123 else 5124 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5125 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5126 5127 /* 5128 * If we have already fixed the size of the static TLS block, we 5129 * must stay within that size. When allocating the static TLS, we 5130 * leave a small amount of space spare to be used for dynamically 5131 * loading modules which use static TLS. 5132 */ 5133 if (tls_static_space != 0) { 5134 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5135 return false; 5136 } else if (obj->tlsalign > tls_static_max_align) { 5137 tls_static_max_align = obj->tlsalign; 5138 } 5139 5140 tls_last_offset = obj->tlsoffset = off; 5141 tls_last_size = obj->tlssize; 5142 obj->tls_done = true; 5143 5144 return true; 5145 } 5146 5147 void 5148 free_tls_offset(Obj_Entry *obj) 5149 { 5150 5151 /* 5152 * If we were the last thing to allocate out of the static TLS 5153 * block, we give our space back to the 'allocator'. This is a 5154 * simplistic workaround to allow libGL.so.1 to be loaded and 5155 * unloaded multiple times. 5156 */ 5157 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5158 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5159 tls_last_offset -= obj->tlssize; 5160 tls_last_size = 0; 5161 } 5162 } 5163 5164 void * 5165 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5166 { 5167 void *ret; 5168 RtldLockState lockstate; 5169 5170 wlock_acquire(rtld_bind_lock, &lockstate); 5171 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5172 tcbsize, tcbalign); 5173 lock_release(rtld_bind_lock, &lockstate); 5174 return (ret); 5175 } 5176 5177 void 5178 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5179 { 5180 RtldLockState lockstate; 5181 5182 wlock_acquire(rtld_bind_lock, &lockstate); 5183 free_tls(tcb, tcbsize, tcbalign); 5184 lock_release(rtld_bind_lock, &lockstate); 5185 } 5186 5187 static void 5188 object_add_name(Obj_Entry *obj, const char *name) 5189 { 5190 Name_Entry *entry; 5191 size_t len; 5192 5193 len = strlen(name); 5194 entry = malloc(sizeof(Name_Entry) + len); 5195 5196 if (entry != NULL) { 5197 strcpy(entry->name, name); 5198 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5199 } 5200 } 5201 5202 static int 5203 object_match_name(const Obj_Entry *obj, const char *name) 5204 { 5205 Name_Entry *entry; 5206 5207 STAILQ_FOREACH(entry, &obj->names, link) { 5208 if (strcmp(name, entry->name) == 0) 5209 return (1); 5210 } 5211 return (0); 5212 } 5213 5214 static Obj_Entry * 5215 locate_dependency(const Obj_Entry *obj, const char *name) 5216 { 5217 const Objlist_Entry *entry; 5218 const Needed_Entry *needed; 5219 5220 STAILQ_FOREACH(entry, &list_main, link) { 5221 if (object_match_name(entry->obj, name)) 5222 return entry->obj; 5223 } 5224 5225 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5226 if (strcmp(obj->strtab + needed->name, name) == 0 || 5227 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5228 /* 5229 * If there is DT_NEEDED for the name we are looking for, 5230 * we are all set. Note that object might not be found if 5231 * dependency was not loaded yet, so the function can 5232 * return NULL here. This is expected and handled 5233 * properly by the caller. 5234 */ 5235 return (needed->obj); 5236 } 5237 } 5238 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5239 obj->path, name); 5240 rtld_die(); 5241 } 5242 5243 static int 5244 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5245 const Elf_Vernaux *vna) 5246 { 5247 const Elf_Verdef *vd; 5248 const char *vername; 5249 5250 vername = refobj->strtab + vna->vna_name; 5251 vd = depobj->verdef; 5252 if (vd == NULL) { 5253 _rtld_error("%s: version %s required by %s not defined", 5254 depobj->path, vername, refobj->path); 5255 return (-1); 5256 } 5257 for (;;) { 5258 if (vd->vd_version != VER_DEF_CURRENT) { 5259 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5260 depobj->path, vd->vd_version); 5261 return (-1); 5262 } 5263 if (vna->vna_hash == vd->vd_hash) { 5264 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5265 ((const char *)vd + vd->vd_aux); 5266 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5267 return (0); 5268 } 5269 if (vd->vd_next == 0) 5270 break; 5271 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5272 } 5273 if (vna->vna_flags & VER_FLG_WEAK) 5274 return (0); 5275 _rtld_error("%s: version %s required by %s not found", 5276 depobj->path, vername, refobj->path); 5277 return (-1); 5278 } 5279 5280 static int 5281 rtld_verify_object_versions(Obj_Entry *obj) 5282 { 5283 const Elf_Verneed *vn; 5284 const Elf_Verdef *vd; 5285 const Elf_Verdaux *vda; 5286 const Elf_Vernaux *vna; 5287 const Obj_Entry *depobj; 5288 int maxvernum, vernum; 5289 5290 if (obj->ver_checked) 5291 return (0); 5292 obj->ver_checked = true; 5293 5294 maxvernum = 0; 5295 /* 5296 * Walk over defined and required version records and figure out 5297 * max index used by any of them. Do very basic sanity checking 5298 * while there. 5299 */ 5300 vn = obj->verneed; 5301 while (vn != NULL) { 5302 if (vn->vn_version != VER_NEED_CURRENT) { 5303 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5304 obj->path, vn->vn_version); 5305 return (-1); 5306 } 5307 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5308 for (;;) { 5309 vernum = VER_NEED_IDX(vna->vna_other); 5310 if (vernum > maxvernum) 5311 maxvernum = vernum; 5312 if (vna->vna_next == 0) 5313 break; 5314 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5315 } 5316 if (vn->vn_next == 0) 5317 break; 5318 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5319 } 5320 5321 vd = obj->verdef; 5322 while (vd != NULL) { 5323 if (vd->vd_version != VER_DEF_CURRENT) { 5324 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5325 obj->path, vd->vd_version); 5326 return (-1); 5327 } 5328 vernum = VER_DEF_IDX(vd->vd_ndx); 5329 if (vernum > maxvernum) 5330 maxvernum = vernum; 5331 if (vd->vd_next == 0) 5332 break; 5333 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5334 } 5335 5336 if (maxvernum == 0) 5337 return (0); 5338 5339 /* 5340 * Store version information in array indexable by version index. 5341 * Verify that object version requirements are satisfied along the 5342 * way. 5343 */ 5344 obj->vernum = maxvernum + 1; 5345 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5346 5347 vd = obj->verdef; 5348 while (vd != NULL) { 5349 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5350 vernum = VER_DEF_IDX(vd->vd_ndx); 5351 assert(vernum <= maxvernum); 5352 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5353 obj->vertab[vernum].hash = vd->vd_hash; 5354 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5355 obj->vertab[vernum].file = NULL; 5356 obj->vertab[vernum].flags = 0; 5357 } 5358 if (vd->vd_next == 0) 5359 break; 5360 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5361 } 5362 5363 vn = obj->verneed; 5364 while (vn != NULL) { 5365 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5366 if (depobj == NULL) 5367 return (-1); 5368 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5369 for (;;) { 5370 if (check_object_provided_version(obj, depobj, vna)) 5371 return (-1); 5372 vernum = VER_NEED_IDX(vna->vna_other); 5373 assert(vernum <= maxvernum); 5374 obj->vertab[vernum].hash = vna->vna_hash; 5375 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5376 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5377 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5378 VER_INFO_HIDDEN : 0; 5379 if (vna->vna_next == 0) 5380 break; 5381 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5382 } 5383 if (vn->vn_next == 0) 5384 break; 5385 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5386 } 5387 return 0; 5388 } 5389 5390 static int 5391 rtld_verify_versions(const Objlist *objlist) 5392 { 5393 Objlist_Entry *entry; 5394 int rc; 5395 5396 rc = 0; 5397 STAILQ_FOREACH(entry, objlist, link) { 5398 /* 5399 * Skip dummy objects or objects that have their version requirements 5400 * already checked. 5401 */ 5402 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5403 continue; 5404 if (rtld_verify_object_versions(entry->obj) == -1) { 5405 rc = -1; 5406 if (ld_tracing == NULL) 5407 break; 5408 } 5409 } 5410 if (rc == 0 || ld_tracing != NULL) 5411 rc = rtld_verify_object_versions(&obj_rtld); 5412 return rc; 5413 } 5414 5415 const Ver_Entry * 5416 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5417 { 5418 Elf_Versym vernum; 5419 5420 if (obj->vertab) { 5421 vernum = VER_NDX(obj->versyms[symnum]); 5422 if (vernum >= obj->vernum) { 5423 _rtld_error("%s: symbol %s has wrong verneed value %d", 5424 obj->path, obj->strtab + symnum, vernum); 5425 } else if (obj->vertab[vernum].hash != 0) { 5426 return &obj->vertab[vernum]; 5427 } 5428 } 5429 return NULL; 5430 } 5431 5432 int 5433 _rtld_get_stack_prot(void) 5434 { 5435 5436 return (stack_prot); 5437 } 5438 5439 int 5440 _rtld_is_dlopened(void *arg) 5441 { 5442 Obj_Entry *obj; 5443 RtldLockState lockstate; 5444 int res; 5445 5446 rlock_acquire(rtld_bind_lock, &lockstate); 5447 obj = dlcheck(arg); 5448 if (obj == NULL) 5449 obj = obj_from_addr(arg); 5450 if (obj == NULL) { 5451 _rtld_error("No shared object contains address"); 5452 lock_release(rtld_bind_lock, &lockstate); 5453 return (-1); 5454 } 5455 res = obj->dlopened ? 1 : 0; 5456 lock_release(rtld_bind_lock, &lockstate); 5457 return (res); 5458 } 5459 5460 static int 5461 obj_remap_relro(Obj_Entry *obj, int prot) 5462 { 5463 5464 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5465 prot) == -1) { 5466 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5467 obj->path, prot, rtld_strerror(errno)); 5468 return (-1); 5469 } 5470 return (0); 5471 } 5472 5473 static int 5474 obj_disable_relro(Obj_Entry *obj) 5475 { 5476 5477 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5478 } 5479 5480 static int 5481 obj_enforce_relro(Obj_Entry *obj) 5482 { 5483 5484 return (obj_remap_relro(obj, PROT_READ)); 5485 } 5486 5487 static void 5488 map_stacks_exec(RtldLockState *lockstate) 5489 { 5490 void (*thr_map_stacks_exec)(void); 5491 5492 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5493 return; 5494 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5495 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5496 if (thr_map_stacks_exec != NULL) { 5497 stack_prot |= PROT_EXEC; 5498 thr_map_stacks_exec(); 5499 } 5500 } 5501 5502 static void 5503 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5504 { 5505 Objlist_Entry *elm; 5506 Obj_Entry *obj; 5507 void (*distrib)(size_t, void *, size_t, size_t); 5508 5509 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5510 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5511 if (distrib == NULL) 5512 return; 5513 STAILQ_FOREACH(elm, list, link) { 5514 obj = elm->obj; 5515 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5516 continue; 5517 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5518 obj->tlssize); 5519 obj->static_tls_copied = true; 5520 } 5521 } 5522 5523 void 5524 symlook_init(SymLook *dst, const char *name) 5525 { 5526 5527 bzero(dst, sizeof(*dst)); 5528 dst->name = name; 5529 dst->hash = elf_hash(name); 5530 dst->hash_gnu = gnu_hash(name); 5531 } 5532 5533 static void 5534 symlook_init_from_req(SymLook *dst, const SymLook *src) 5535 { 5536 5537 dst->name = src->name; 5538 dst->hash = src->hash; 5539 dst->hash_gnu = src->hash_gnu; 5540 dst->ventry = src->ventry; 5541 dst->flags = src->flags; 5542 dst->defobj_out = NULL; 5543 dst->sym_out = NULL; 5544 dst->lockstate = src->lockstate; 5545 } 5546 5547 static int 5548 open_binary_fd(const char *argv0, bool search_in_path, 5549 const char **binpath_res) 5550 { 5551 char *binpath, *pathenv, *pe, *res1; 5552 const char *res; 5553 int fd; 5554 5555 binpath = NULL; 5556 res = NULL; 5557 if (search_in_path && strchr(argv0, '/') == NULL) { 5558 binpath = xmalloc(PATH_MAX); 5559 pathenv = getenv("PATH"); 5560 if (pathenv == NULL) { 5561 _rtld_error("-p and no PATH environment variable"); 5562 rtld_die(); 5563 } 5564 pathenv = strdup(pathenv); 5565 if (pathenv == NULL) { 5566 _rtld_error("Cannot allocate memory"); 5567 rtld_die(); 5568 } 5569 fd = -1; 5570 errno = ENOENT; 5571 while ((pe = strsep(&pathenv, ":")) != NULL) { 5572 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5573 continue; 5574 if (binpath[0] != '\0' && 5575 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5576 continue; 5577 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5578 continue; 5579 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5580 if (fd != -1 || errno != ENOENT) { 5581 res = binpath; 5582 break; 5583 } 5584 } 5585 free(pathenv); 5586 } else { 5587 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5588 res = argv0; 5589 } 5590 5591 if (fd == -1) { 5592 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5593 rtld_die(); 5594 } 5595 if (res != NULL && res[0] != '/') { 5596 res1 = xmalloc(PATH_MAX); 5597 if (realpath(res, res1) != NULL) { 5598 if (res != argv0) 5599 free(__DECONST(char *, res)); 5600 res = res1; 5601 } else { 5602 free(res1); 5603 } 5604 } 5605 *binpath_res = res; 5606 return (fd); 5607 } 5608 5609 /* 5610 * Parse a set of command-line arguments. 5611 */ 5612 static int 5613 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5614 { 5615 const char *arg; 5616 int fd, i, j, arglen; 5617 char opt; 5618 5619 dbg("Parsing command-line arguments"); 5620 *use_pathp = false; 5621 *fdp = -1; 5622 5623 for (i = 1; i < argc; i++ ) { 5624 arg = argv[i]; 5625 dbg("argv[%d]: '%s'", i, arg); 5626 5627 /* 5628 * rtld arguments end with an explicit "--" or with the first 5629 * non-prefixed argument. 5630 */ 5631 if (strcmp(arg, "--") == 0) { 5632 i++; 5633 break; 5634 } 5635 if (arg[0] != '-') 5636 break; 5637 5638 /* 5639 * All other arguments are single-character options that can 5640 * be combined, so we need to search through `arg` for them. 5641 */ 5642 arglen = strlen(arg); 5643 for (j = 1; j < arglen; j++) { 5644 opt = arg[j]; 5645 if (opt == 'h') { 5646 print_usage(argv[0]); 5647 _exit(0); 5648 } else if (opt == 'f') { 5649 /* 5650 * -f XX can be used to specify a 5651 * descriptor for the binary named at 5652 * the command line (i.e., the later 5653 * argument will specify the process 5654 * name but the descriptor is what 5655 * will actually be executed). 5656 * 5657 * -f must be the last option in, e.g., -abcf. 5658 */ 5659 if (j != arglen - 1) { 5660 _rtld_error("Invalid options: %s", arg); 5661 rtld_die(); 5662 } 5663 i++; 5664 fd = parse_integer(argv[i]); 5665 if (fd == -1) { 5666 _rtld_error( 5667 "Invalid file descriptor: '%s'", 5668 argv[i]); 5669 rtld_die(); 5670 } 5671 *fdp = fd; 5672 break; 5673 } else if (opt == 'p') { 5674 *use_pathp = true; 5675 } else { 5676 _rtld_error("Invalid argument: '%s'", arg); 5677 print_usage(argv[0]); 5678 rtld_die(); 5679 } 5680 } 5681 } 5682 5683 return (i); 5684 } 5685 5686 /* 5687 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5688 */ 5689 static int 5690 parse_integer(const char *str) 5691 { 5692 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5693 const char *orig; 5694 int n; 5695 char c; 5696 5697 orig = str; 5698 n = 0; 5699 for (c = *str; c != '\0'; c = *++str) { 5700 if (c < '0' || c > '9') 5701 return (-1); 5702 5703 n *= RADIX; 5704 n += c - '0'; 5705 } 5706 5707 /* Make sure we actually parsed something. */ 5708 if (str == orig) 5709 return (-1); 5710 return (n); 5711 } 5712 5713 static void 5714 print_usage(const char *argv0) 5715 { 5716 5717 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5718 "\n" 5719 "Options:\n" 5720 " -h Display this help message\n" 5721 " -p Search in PATH for named binary\n" 5722 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5723 " -- End of RTLD options\n" 5724 " <binary> Name of process to execute\n" 5725 " <args> Arguments to the executed process\n", argv0); 5726 } 5727 5728 /* 5729 * Overrides for libc_pic-provided functions. 5730 */ 5731 5732 int 5733 __getosreldate(void) 5734 { 5735 size_t len; 5736 int oid[2]; 5737 int error, osrel; 5738 5739 if (osreldate != 0) 5740 return (osreldate); 5741 5742 oid[0] = CTL_KERN; 5743 oid[1] = KERN_OSRELDATE; 5744 osrel = 0; 5745 len = sizeof(osrel); 5746 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5747 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5748 osreldate = osrel; 5749 return (osreldate); 5750 } 5751 const char * 5752 rtld_strerror(int errnum) 5753 { 5754 5755 if (errnum < 0 || errnum >= sys_nerr) 5756 return ("Unknown error"); 5757 return (sys_errlist[errnum]); 5758 } 5759 5760 /* malloc */ 5761 void * 5762 malloc(size_t nbytes) 5763 { 5764 5765 return (__crt_malloc(nbytes)); 5766 } 5767 5768 void * 5769 calloc(size_t num, size_t size) 5770 { 5771 5772 return (__crt_calloc(num, size)); 5773 } 5774 5775 void 5776 free(void *cp) 5777 { 5778 5779 __crt_free(cp); 5780 } 5781 5782 void * 5783 realloc(void *cp, size_t nbytes) 5784 { 5785 5786 return (__crt_realloc(cp, nbytes)); 5787 } 5788 5789 extern int _rtld_version__FreeBSD_version __exported; 5790 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5791 5792 extern char _rtld_version_laddr_offset __exported; 5793 char _rtld_version_laddr_offset; 5794