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 const char **argv0); 141 static int parse_integer(const char *); 142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 143 static void print_usage(const char *argv0); 144 static void release_object(Obj_Entry *); 145 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 148 int flags, RtldLockState *lockstate); 149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 150 RtldLockState *); 151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 152 static int rtld_dirname(const char *, char *); 153 static int rtld_dirname_abs(const char *, char *); 154 static void *rtld_dlopen(const char *name, int fd, int mode); 155 static void rtld_exit(void); 156 static void rtld_nop_exit(void); 157 static char *search_library_path(const char *, const char *, const char *, 158 int *); 159 static char *search_library_pathfds(const char *, const char *, int *); 160 static const void **get_program_var_addr(const char *, RtldLockState *); 161 static void set_program_var(const char *, const void *); 162 static int symlook_default(SymLook *, const Obj_Entry *refobj); 163 static int symlook_global(SymLook *, DoneList *); 164 static void symlook_init_from_req(SymLook *, const SymLook *); 165 static int symlook_list(SymLook *, const Objlist *, DoneList *); 166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 169 static void trace_loaded_objects(Obj_Entry *); 170 static void unlink_object(Obj_Entry *); 171 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 172 static void unref_dag(Obj_Entry *); 173 static void ref_dag(Obj_Entry *); 174 static char *origin_subst_one(Obj_Entry *, char *, const char *, 175 const char *, bool); 176 static char *origin_subst(Obj_Entry *, const char *); 177 static bool obj_resolve_origin(Obj_Entry *obj); 178 static void preinit_main(void); 179 static int rtld_verify_versions(const Objlist *); 180 static int rtld_verify_object_versions(Obj_Entry *); 181 static void object_add_name(Obj_Entry *, const char *); 182 static int object_match_name(const Obj_Entry *, const char *); 183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 185 struct dl_phdr_info *phdr_info); 186 static uint32_t gnu_hash(const char *); 187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 188 const unsigned long); 189 190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 191 void _r_debug_postinit(struct link_map *) __noinline __exported; 192 193 int __sys_openat(int, const char *, int, ...); 194 195 /* 196 * Data declarations. 197 */ 198 static char *error_message; /* Message for dlerror(), or NULL */ 199 struct r_debug r_debug __exported; /* for GDB; */ 200 static bool libmap_disable; /* Disable libmap */ 201 static bool ld_loadfltr; /* Immediate filters processing */ 202 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 203 static bool trust; /* False for setuid and setgid programs */ 204 static bool dangerous_ld_env; /* True if environment variables have been 205 used to affect the libraries loaded */ 206 bool ld_bind_not; /* Disable PLT update */ 207 static char *ld_bind_now; /* Environment variable for immediate binding */ 208 static char *ld_debug; /* Environment variable for debugging */ 209 static char *ld_library_path; /* Environment variable for search path */ 210 static char *ld_library_dirs; /* Environment variable for library descriptors */ 211 static char *ld_preload; /* Environment variable for libraries to 212 load first */ 213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 214 static const char *ld_tracing; /* Called from ldd to print libs */ 215 static char *ld_utrace; /* Use utrace() to log events. */ 216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 217 static Obj_Entry *obj_main; /* The main program shared object */ 218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 219 static unsigned int obj_count; /* Number of objects in obj_list */ 220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 221 222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 223 STAILQ_HEAD_INITIALIZER(list_global); 224 static Objlist list_main = /* Objects loaded at program startup */ 225 STAILQ_HEAD_INITIALIZER(list_main); 226 static Objlist list_fini = /* Objects needing fini() calls */ 227 STAILQ_HEAD_INITIALIZER(list_fini); 228 229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 230 231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 232 233 extern Elf_Dyn _DYNAMIC; 234 #pragma weak _DYNAMIC 235 236 int dlclose(void *) __exported; 237 char *dlerror(void) __exported; 238 void *dlopen(const char *, int) __exported; 239 void *fdlopen(int, int) __exported; 240 void *dlsym(void *, const char *) __exported; 241 dlfunc_t dlfunc(void *, const char *) __exported; 242 void *dlvsym(void *, const char *, const char *) __exported; 243 int dladdr(const void *, Dl_info *) __exported; 244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 246 int dlinfo(void *, int , void *) __exported; 247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 249 int _rtld_get_stack_prot(void) __exported; 250 int _rtld_is_dlopened(void *) __exported; 251 void _rtld_error(const char *, ...) __exported; 252 253 /* Only here to fix -Wmissing-prototypes warnings */ 254 int __getosreldate(void); 255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 257 258 259 int npagesizes; 260 static int osreldate; 261 size_t *pagesizes; 262 263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 264 static int max_stack_flags; 265 266 /* 267 * Global declarations normally provided by crt1. The dynamic linker is 268 * not built with crt1, so we have to provide them ourselves. 269 */ 270 char *__progname; 271 char **environ; 272 273 /* 274 * Used to pass argc, argv to init functions. 275 */ 276 int main_argc; 277 char **main_argv; 278 279 /* 280 * Globals to control TLS allocation. 281 */ 282 size_t tls_last_offset; /* Static TLS offset of last module */ 283 size_t tls_last_size; /* Static TLS size of last module */ 284 size_t tls_static_space; /* Static TLS space allocated */ 285 static size_t tls_static_max_align; 286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 287 int tls_max_index = 1; /* Largest module index allocated */ 288 289 static bool ld_library_path_rpath = false; 290 bool ld_fast_sigblock = false; 291 292 /* 293 * Globals for path names, and such 294 */ 295 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 297 const char *ld_path_rtld = _PATH_RTLD; 298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 299 const char *ld_env_prefix = LD_; 300 301 static void (*rtld_exit_ptr)(void); 302 303 /* 304 * Fill in a DoneList with an allocation large enough to hold all of 305 * the currently-loaded objects. Keep this as a macro since it calls 306 * alloca and we want that to occur within the scope of the caller. 307 */ 308 #define donelist_init(dlp) \ 309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 310 assert((dlp)->objs != NULL), \ 311 (dlp)->num_alloc = obj_count, \ 312 (dlp)->num_used = 0) 313 314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 315 if (ld_utrace != NULL) \ 316 ld_utrace_log(e, h, mb, ms, r, n); \ 317 } while (0) 318 319 static void 320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 321 int refcnt, const char *name) 322 { 323 struct utrace_rtld ut; 324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 325 326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 327 ut.event = event; 328 ut.handle = handle; 329 ut.mapbase = mapbase; 330 ut.mapsize = mapsize; 331 ut.refcnt = refcnt; 332 bzero(ut.name, sizeof(ut.name)); 333 if (name) 334 strlcpy(ut.name, name, sizeof(ut.name)); 335 utrace(&ut, sizeof(ut)); 336 } 337 338 #ifdef RTLD_VARIANT_ENV_NAMES 339 /* 340 * construct the env variable based on the type of binary that's 341 * running. 342 */ 343 static inline const char * 344 _LD(const char *var) 345 { 346 static char buffer[128]; 347 348 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 349 strlcat(buffer, var, sizeof(buffer)); 350 return (buffer); 351 } 352 #else 353 #define _LD(x) LD_ x 354 #endif 355 356 /* 357 * Main entry point for dynamic linking. The first argument is the 358 * stack pointer. The stack is expected to be laid out as described 359 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 360 * Specifically, the stack pointer points to a word containing 361 * ARGC. Following that in the stack is a null-terminated sequence 362 * of pointers to argument strings. Then comes a null-terminated 363 * sequence of pointers to environment strings. Finally, there is a 364 * sequence of "auxiliary vector" entries. 365 * 366 * The second argument points to a place to store the dynamic linker's 367 * exit procedure pointer and the third to a place to store the main 368 * program's object. 369 * 370 * The return value is the main program's entry point. 371 */ 372 func_ptr_type 373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 374 { 375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 376 Objlist_Entry *entry; 377 Obj_Entry *last_interposer, *obj, *preload_tail; 378 const Elf_Phdr *phdr; 379 Objlist initlist; 380 RtldLockState lockstate; 381 struct stat st; 382 Elf_Addr *argcp; 383 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 384 const char *argv0, *binpath; 385 caddr_t imgentry; 386 char buf[MAXPATHLEN]; 387 int argc, fd, i, phnum, rtld_argc; 388 #ifdef __powerpc__ 389 int old_auxv_format = 1; 390 #endif 391 bool dir_enable, explicit_fd, search_in_path; 392 393 /* 394 * On entry, the dynamic linker itself has not been relocated yet. 395 * Be very careful not to reference any global data until after 396 * init_rtld has returned. It is OK to reference file-scope statics 397 * and string constants, and to call static and global functions. 398 */ 399 400 /* Find the auxiliary vector on the stack. */ 401 argcp = sp; 402 argc = *sp++; 403 argv = (char **) sp; 404 sp += argc + 1; /* Skip over arguments and NULL terminator */ 405 env = (char **) sp; 406 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 407 ; 408 aux = (Elf_Auxinfo *) sp; 409 410 /* Digest the auxiliary vector. */ 411 for (i = 0; i < AT_COUNT; i++) 412 aux_info[i] = NULL; 413 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 414 if (auxp->a_type < AT_COUNT) 415 aux_info[auxp->a_type] = auxp; 416 #ifdef __powerpc__ 417 if (auxp->a_type == 23) /* AT_STACKPROT */ 418 old_auxv_format = 0; 419 #endif 420 } 421 422 #ifdef __powerpc__ 423 if (old_auxv_format) { 424 /* Remap from old-style auxv numbers. */ 425 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 426 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 427 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 428 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 429 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 430 aux_info[13] = NULL; /* AT_GID */ 431 432 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 433 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 434 aux_info[16] = aux_info[14]; /* AT_CANARY */ 435 aux_info[14] = NULL; /* AT_EGID */ 436 } 437 #endif 438 439 /* Initialize and relocate ourselves. */ 440 assert(aux_info[AT_BASE] != NULL); 441 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 442 443 __progname = obj_rtld.path; 444 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 445 environ = env; 446 main_argc = argc; 447 main_argv = argv; 448 449 if (aux_info[AT_BSDFLAGS] != NULL && 450 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 451 ld_fast_sigblock = true; 452 453 trust = !issetugid(); 454 455 md_abi_variant_hook(aux_info); 456 457 fd = -1; 458 if (aux_info[AT_EXECFD] != NULL) { 459 fd = aux_info[AT_EXECFD]->a_un.a_val; 460 } else { 461 assert(aux_info[AT_PHDR] != NULL); 462 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 463 if (phdr == obj_rtld.phdr) { 464 if (!trust) { 465 _rtld_error("Tainted process refusing to run binary %s", 466 argv0); 467 rtld_die(); 468 } 469 dbg("opening main program in direct exec mode"); 470 if (argc >= 2) { 471 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 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 if (dynp->d_un.d_val & DF_1_PIE) 1374 obj->z_pie = true; 1375 break; 1376 1377 default: 1378 if (!early) { 1379 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1380 (long)dynp->d_tag); 1381 } 1382 break; 1383 } 1384 } 1385 1386 obj->traced = false; 1387 1388 if (plttype == DT_RELA) { 1389 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1390 obj->pltrel = NULL; 1391 obj->pltrelasize = obj->pltrelsize; 1392 obj->pltrelsize = 0; 1393 } 1394 1395 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1396 if (obj->valid_hash_sysv) 1397 obj->dynsymcount = obj->nchains; 1398 else if (obj->valid_hash_gnu) { 1399 obj->dynsymcount = 0; 1400 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1401 if (obj->buckets_gnu[bkt] == 0) 1402 continue; 1403 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1404 do 1405 obj->dynsymcount++; 1406 while ((*hashval++ & 1u) == 0); 1407 } 1408 obj->dynsymcount += obj->symndx_gnu; 1409 } 1410 1411 if (obj->linkmap.l_refname != NULL) 1412 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1413 linkmap.l_refname; 1414 } 1415 1416 static bool 1417 obj_resolve_origin(Obj_Entry *obj) 1418 { 1419 1420 if (obj->origin_path != NULL) 1421 return (true); 1422 obj->origin_path = xmalloc(PATH_MAX); 1423 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1424 } 1425 1426 static bool 1427 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1428 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1429 { 1430 1431 if (obj->z_origin && !obj_resolve_origin(obj)) 1432 return (false); 1433 1434 if (dyn_runpath != NULL) { 1435 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1436 obj->runpath = origin_subst(obj, obj->runpath); 1437 } else if (dyn_rpath != NULL) { 1438 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1439 obj->rpath = origin_subst(obj, obj->rpath); 1440 } 1441 if (dyn_soname != NULL) 1442 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1443 return (true); 1444 } 1445 1446 static bool 1447 digest_dynamic(Obj_Entry *obj, int early) 1448 { 1449 const Elf_Dyn *dyn_rpath; 1450 const Elf_Dyn *dyn_soname; 1451 const Elf_Dyn *dyn_runpath; 1452 1453 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1454 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1455 } 1456 1457 /* 1458 * Process a shared object's program header. This is used only for the 1459 * main program, when the kernel has already loaded the main program 1460 * into memory before calling the dynamic linker. It creates and 1461 * returns an Obj_Entry structure. 1462 */ 1463 static Obj_Entry * 1464 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1465 { 1466 Obj_Entry *obj; 1467 const Elf_Phdr *phlimit = phdr + phnum; 1468 const Elf_Phdr *ph; 1469 Elf_Addr note_start, note_end; 1470 int nsegs = 0; 1471 1472 obj = obj_new(); 1473 for (ph = phdr; ph < phlimit; ph++) { 1474 if (ph->p_type != PT_PHDR) 1475 continue; 1476 1477 obj->phdr = phdr; 1478 obj->phsize = ph->p_memsz; 1479 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1480 break; 1481 } 1482 1483 obj->stack_flags = PF_X | PF_R | PF_W; 1484 1485 for (ph = phdr; ph < phlimit; ph++) { 1486 switch (ph->p_type) { 1487 1488 case PT_INTERP: 1489 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1490 break; 1491 1492 case PT_LOAD: 1493 if (nsegs == 0) { /* First load segment */ 1494 obj->vaddrbase = trunc_page(ph->p_vaddr); 1495 obj->mapbase = obj->vaddrbase + obj->relocbase; 1496 } else { /* Last load segment */ 1497 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1498 obj->vaddrbase; 1499 } 1500 nsegs++; 1501 break; 1502 1503 case PT_DYNAMIC: 1504 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1505 break; 1506 1507 case PT_TLS: 1508 obj->tlsindex = 1; 1509 obj->tlssize = ph->p_memsz; 1510 obj->tlsalign = ph->p_align; 1511 obj->tlsinitsize = ph->p_filesz; 1512 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1513 obj->tlspoffset = ph->p_offset; 1514 break; 1515 1516 case PT_GNU_STACK: 1517 obj->stack_flags = ph->p_flags; 1518 break; 1519 1520 case PT_GNU_RELRO: 1521 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1522 obj->relro_size = round_page(ph->p_memsz); 1523 break; 1524 1525 case PT_NOTE: 1526 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1527 note_end = note_start + ph->p_filesz; 1528 digest_notes(obj, note_start, note_end); 1529 break; 1530 } 1531 } 1532 if (nsegs < 1) { 1533 _rtld_error("%s: too few PT_LOAD segments", path); 1534 return NULL; 1535 } 1536 1537 obj->entry = entry; 1538 return obj; 1539 } 1540 1541 void 1542 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1543 { 1544 const Elf_Note *note; 1545 const char *note_name; 1546 uintptr_t p; 1547 1548 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1549 note = (const Elf_Note *)((const char *)(note + 1) + 1550 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1551 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1552 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1553 note->n_descsz != sizeof(int32_t)) 1554 continue; 1555 if (note->n_type != NT_FREEBSD_ABI_TAG && 1556 note->n_type != NT_FREEBSD_FEATURE_CTL && 1557 note->n_type != NT_FREEBSD_NOINIT_TAG) 1558 continue; 1559 note_name = (const char *)(note + 1); 1560 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1561 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1562 continue; 1563 switch (note->n_type) { 1564 case NT_FREEBSD_ABI_TAG: 1565 /* FreeBSD osrel note */ 1566 p = (uintptr_t)(note + 1); 1567 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1568 obj->osrel = *(const int32_t *)(p); 1569 dbg("note osrel %d", obj->osrel); 1570 break; 1571 case NT_FREEBSD_FEATURE_CTL: 1572 /* FreeBSD ABI feature control note */ 1573 p = (uintptr_t)(note + 1); 1574 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1575 obj->fctl0 = *(const uint32_t *)(p); 1576 dbg("note fctl0 %#x", obj->fctl0); 1577 break; 1578 case NT_FREEBSD_NOINIT_TAG: 1579 /* FreeBSD 'crt does not call init' note */ 1580 obj->crt_no_init = true; 1581 dbg("note crt_no_init"); 1582 break; 1583 } 1584 } 1585 } 1586 1587 static Obj_Entry * 1588 dlcheck(void *handle) 1589 { 1590 Obj_Entry *obj; 1591 1592 TAILQ_FOREACH(obj, &obj_list, next) { 1593 if (obj == (Obj_Entry *) handle) 1594 break; 1595 } 1596 1597 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1598 _rtld_error("Invalid shared object handle %p", handle); 1599 return NULL; 1600 } 1601 return obj; 1602 } 1603 1604 /* 1605 * If the given object is already in the donelist, return true. Otherwise 1606 * add the object to the list and return false. 1607 */ 1608 static bool 1609 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1610 { 1611 unsigned int i; 1612 1613 for (i = 0; i < dlp->num_used; i++) 1614 if (dlp->objs[i] == obj) 1615 return true; 1616 /* 1617 * Our donelist allocation should always be sufficient. But if 1618 * our threads locking isn't working properly, more shared objects 1619 * could have been loaded since we allocated the list. That should 1620 * never happen, but we'll handle it properly just in case it does. 1621 */ 1622 if (dlp->num_used < dlp->num_alloc) 1623 dlp->objs[dlp->num_used++] = obj; 1624 return false; 1625 } 1626 1627 /* 1628 * Hash function for symbol table lookup. Don't even think about changing 1629 * this. It is specified by the System V ABI. 1630 */ 1631 unsigned long 1632 elf_hash(const char *name) 1633 { 1634 const unsigned char *p = (const unsigned char *) name; 1635 unsigned long h = 0; 1636 unsigned long g; 1637 1638 while (*p != '\0') { 1639 h = (h << 4) + *p++; 1640 if ((g = h & 0xf0000000) != 0) 1641 h ^= g >> 24; 1642 h &= ~g; 1643 } 1644 return h; 1645 } 1646 1647 /* 1648 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1649 * unsigned in case it's implemented with a wider type. 1650 */ 1651 static uint32_t 1652 gnu_hash(const char *s) 1653 { 1654 uint32_t h; 1655 unsigned char c; 1656 1657 h = 5381; 1658 for (c = *s; c != '\0'; c = *++s) 1659 h = h * 33 + c; 1660 return (h & 0xffffffff); 1661 } 1662 1663 1664 /* 1665 * Find the library with the given name, and return its full pathname. 1666 * The returned string is dynamically allocated. Generates an error 1667 * message and returns NULL if the library cannot be found. 1668 * 1669 * If the second argument is non-NULL, then it refers to an already- 1670 * loaded shared object, whose library search path will be searched. 1671 * 1672 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1673 * descriptor (which is close-on-exec) will be passed out via the third 1674 * argument. 1675 * 1676 * The search order is: 1677 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1678 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1679 * LD_LIBRARY_PATH 1680 * DT_RUNPATH in the referencing file 1681 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1682 * from list) 1683 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1684 * 1685 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1686 */ 1687 static char * 1688 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1689 { 1690 char *pathname, *refobj_path; 1691 const char *name; 1692 bool nodeflib, objgiven; 1693 1694 objgiven = refobj != NULL; 1695 1696 if (libmap_disable || !objgiven || 1697 (name = lm_find(refobj->path, xname)) == NULL) 1698 name = xname; 1699 1700 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1701 if (name[0] != '/' && !trust) { 1702 _rtld_error("Absolute pathname required " 1703 "for shared object \"%s\"", name); 1704 return (NULL); 1705 } 1706 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1707 __DECONST(char *, name))); 1708 } 1709 1710 dbg(" Searching for \"%s\"", name); 1711 refobj_path = objgiven ? refobj->path : NULL; 1712 1713 /* 1714 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1715 * back to pre-conforming behaviour if user requested so with 1716 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1717 * nodeflib. 1718 */ 1719 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1720 pathname = search_library_path(name, ld_library_path, 1721 refobj_path, fdp); 1722 if (pathname != NULL) 1723 return (pathname); 1724 if (refobj != NULL) { 1725 pathname = search_library_path(name, refobj->rpath, 1726 refobj_path, fdp); 1727 if (pathname != NULL) 1728 return (pathname); 1729 } 1730 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1731 if (pathname != NULL) 1732 return (pathname); 1733 pathname = search_library_path(name, gethints(false), 1734 refobj_path, fdp); 1735 if (pathname != NULL) 1736 return (pathname); 1737 pathname = search_library_path(name, ld_standard_library_path, 1738 refobj_path, fdp); 1739 if (pathname != NULL) 1740 return (pathname); 1741 } else { 1742 nodeflib = objgiven ? refobj->z_nodeflib : false; 1743 if (objgiven) { 1744 pathname = search_library_path(name, refobj->rpath, 1745 refobj->path, fdp); 1746 if (pathname != NULL) 1747 return (pathname); 1748 } 1749 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1750 pathname = search_library_path(name, obj_main->rpath, 1751 refobj_path, fdp); 1752 if (pathname != NULL) 1753 return (pathname); 1754 } 1755 pathname = search_library_path(name, ld_library_path, 1756 refobj_path, fdp); 1757 if (pathname != NULL) 1758 return (pathname); 1759 if (objgiven) { 1760 pathname = search_library_path(name, refobj->runpath, 1761 refobj_path, fdp); 1762 if (pathname != NULL) 1763 return (pathname); 1764 } 1765 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1766 if (pathname != NULL) 1767 return (pathname); 1768 pathname = search_library_path(name, gethints(nodeflib), 1769 refobj_path, fdp); 1770 if (pathname != NULL) 1771 return (pathname); 1772 if (objgiven && !nodeflib) { 1773 pathname = search_library_path(name, 1774 ld_standard_library_path, refobj_path, fdp); 1775 if (pathname != NULL) 1776 return (pathname); 1777 } 1778 } 1779 1780 if (objgiven && refobj->path != NULL) { 1781 _rtld_error("Shared object \"%s\" not found, " 1782 "required by \"%s\"", name, basename(refobj->path)); 1783 } else { 1784 _rtld_error("Shared object \"%s\" not found", name); 1785 } 1786 return (NULL); 1787 } 1788 1789 /* 1790 * Given a symbol number in a referencing object, find the corresponding 1791 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1792 * no definition was found. Returns a pointer to the Obj_Entry of the 1793 * defining object via the reference parameter DEFOBJ_OUT. 1794 */ 1795 const Elf_Sym * 1796 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1797 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1798 RtldLockState *lockstate) 1799 { 1800 const Elf_Sym *ref; 1801 const Elf_Sym *def; 1802 const Obj_Entry *defobj; 1803 const Ver_Entry *ve; 1804 SymLook req; 1805 const char *name; 1806 int res; 1807 1808 /* 1809 * If we have already found this symbol, get the information from 1810 * the cache. 1811 */ 1812 if (symnum >= refobj->dynsymcount) 1813 return NULL; /* Bad object */ 1814 if (cache != NULL && cache[symnum].sym != NULL) { 1815 *defobj_out = cache[symnum].obj; 1816 return cache[symnum].sym; 1817 } 1818 1819 ref = refobj->symtab + symnum; 1820 name = refobj->strtab + ref->st_name; 1821 def = NULL; 1822 defobj = NULL; 1823 ve = NULL; 1824 1825 /* 1826 * We don't have to do a full scale lookup if the symbol is local. 1827 * We know it will bind to the instance in this load module; to 1828 * which we already have a pointer (ie ref). By not doing a lookup, 1829 * we not only improve performance, but it also avoids unresolvable 1830 * symbols when local symbols are not in the hash table. This has 1831 * been seen with the ia64 toolchain. 1832 */ 1833 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1834 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1835 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1836 symnum); 1837 } 1838 symlook_init(&req, name); 1839 req.flags = flags; 1840 ve = req.ventry = fetch_ventry(refobj, symnum); 1841 req.lockstate = lockstate; 1842 res = symlook_default(&req, refobj); 1843 if (res == 0) { 1844 def = req.sym_out; 1845 defobj = req.defobj_out; 1846 } 1847 } else { 1848 def = ref; 1849 defobj = refobj; 1850 } 1851 1852 /* 1853 * If we found no definition and the reference is weak, treat the 1854 * symbol as having the value zero. 1855 */ 1856 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1857 def = &sym_zero; 1858 defobj = obj_main; 1859 } 1860 1861 if (def != NULL) { 1862 *defobj_out = defobj; 1863 /* Record the information in the cache to avoid subsequent lookups. */ 1864 if (cache != NULL) { 1865 cache[symnum].sym = def; 1866 cache[symnum].obj = defobj; 1867 } 1868 } else { 1869 if (refobj != &obj_rtld) 1870 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1871 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1872 } 1873 return def; 1874 } 1875 1876 /* 1877 * Return the search path from the ldconfig hints file, reading it if 1878 * necessary. If nostdlib is true, then the default search paths are 1879 * not added to result. 1880 * 1881 * Returns NULL if there are problems with the hints file, 1882 * or if the search path there is empty. 1883 */ 1884 static const char * 1885 gethints(bool nostdlib) 1886 { 1887 static char *filtered_path; 1888 static const char *hints; 1889 static struct elfhints_hdr hdr; 1890 struct fill_search_info_args sargs, hargs; 1891 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1892 struct dl_serpath *SLPpath, *hintpath; 1893 char *p; 1894 struct stat hint_stat; 1895 unsigned int SLPndx, hintndx, fndx, fcount; 1896 int fd; 1897 size_t flen; 1898 uint32_t dl; 1899 bool skip; 1900 1901 /* First call, read the hints file */ 1902 if (hints == NULL) { 1903 /* Keep from trying again in case the hints file is bad. */ 1904 hints = ""; 1905 1906 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1907 return (NULL); 1908 1909 /* 1910 * Check of hdr.dirlistlen value against type limit 1911 * intends to pacify static analyzers. Further 1912 * paranoia leads to checks that dirlist is fully 1913 * contained in the file range. 1914 */ 1915 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1916 hdr.magic != ELFHINTS_MAGIC || 1917 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1918 fstat(fd, &hint_stat) == -1) { 1919 cleanup1: 1920 close(fd); 1921 hdr.dirlistlen = 0; 1922 return (NULL); 1923 } 1924 dl = hdr.strtab; 1925 if (dl + hdr.dirlist < dl) 1926 goto cleanup1; 1927 dl += hdr.dirlist; 1928 if (dl + hdr.dirlistlen < dl) 1929 goto cleanup1; 1930 dl += hdr.dirlistlen; 1931 if (dl > hint_stat.st_size) 1932 goto cleanup1; 1933 p = xmalloc(hdr.dirlistlen + 1); 1934 if (pread(fd, p, hdr.dirlistlen + 1, 1935 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1936 p[hdr.dirlistlen] != '\0') { 1937 free(p); 1938 goto cleanup1; 1939 } 1940 hints = p; 1941 close(fd); 1942 } 1943 1944 /* 1945 * If caller agreed to receive list which includes the default 1946 * paths, we are done. Otherwise, if we still did not 1947 * calculated filtered result, do it now. 1948 */ 1949 if (!nostdlib) 1950 return (hints[0] != '\0' ? hints : NULL); 1951 if (filtered_path != NULL) 1952 goto filt_ret; 1953 1954 /* 1955 * Obtain the list of all configured search paths, and the 1956 * list of the default paths. 1957 * 1958 * First estimate the size of the results. 1959 */ 1960 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1961 smeta.dls_cnt = 0; 1962 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1963 hmeta.dls_cnt = 0; 1964 1965 sargs.request = RTLD_DI_SERINFOSIZE; 1966 sargs.serinfo = &smeta; 1967 hargs.request = RTLD_DI_SERINFOSIZE; 1968 hargs.serinfo = &hmeta; 1969 1970 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1971 &sargs); 1972 path_enumerate(hints, fill_search_info, NULL, &hargs); 1973 1974 SLPinfo = xmalloc(smeta.dls_size); 1975 hintinfo = xmalloc(hmeta.dls_size); 1976 1977 /* 1978 * Next fetch both sets of paths. 1979 */ 1980 sargs.request = RTLD_DI_SERINFO; 1981 sargs.serinfo = SLPinfo; 1982 sargs.serpath = &SLPinfo->dls_serpath[0]; 1983 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1984 1985 hargs.request = RTLD_DI_SERINFO; 1986 hargs.serinfo = hintinfo; 1987 hargs.serpath = &hintinfo->dls_serpath[0]; 1988 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1989 1990 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1991 &sargs); 1992 path_enumerate(hints, fill_search_info, NULL, &hargs); 1993 1994 /* 1995 * Now calculate the difference between two sets, by excluding 1996 * standard paths from the full set. 1997 */ 1998 fndx = 0; 1999 fcount = 0; 2000 filtered_path = xmalloc(hdr.dirlistlen + 1); 2001 hintpath = &hintinfo->dls_serpath[0]; 2002 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2003 skip = false; 2004 SLPpath = &SLPinfo->dls_serpath[0]; 2005 /* 2006 * Check each standard path against current. 2007 */ 2008 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2009 /* matched, skip the path */ 2010 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2011 skip = true; 2012 break; 2013 } 2014 } 2015 if (skip) 2016 continue; 2017 /* 2018 * Not matched against any standard path, add the path 2019 * to result. Separate consequtive paths with ':'. 2020 */ 2021 if (fcount > 0) { 2022 filtered_path[fndx] = ':'; 2023 fndx++; 2024 } 2025 fcount++; 2026 flen = strlen(hintpath->dls_name); 2027 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2028 fndx += flen; 2029 } 2030 filtered_path[fndx] = '\0'; 2031 2032 free(SLPinfo); 2033 free(hintinfo); 2034 2035 filt_ret: 2036 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2037 } 2038 2039 static void 2040 init_dag(Obj_Entry *root) 2041 { 2042 const Needed_Entry *needed; 2043 const Objlist_Entry *elm; 2044 DoneList donelist; 2045 2046 if (root->dag_inited) 2047 return; 2048 donelist_init(&donelist); 2049 2050 /* Root object belongs to own DAG. */ 2051 objlist_push_tail(&root->dldags, root); 2052 objlist_push_tail(&root->dagmembers, root); 2053 donelist_check(&donelist, root); 2054 2055 /* 2056 * Add dependencies of root object to DAG in breadth order 2057 * by exploiting the fact that each new object get added 2058 * to the tail of the dagmembers list. 2059 */ 2060 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2061 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2062 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2063 continue; 2064 objlist_push_tail(&needed->obj->dldags, root); 2065 objlist_push_tail(&root->dagmembers, needed->obj); 2066 } 2067 } 2068 root->dag_inited = true; 2069 } 2070 2071 static void 2072 init_marker(Obj_Entry *marker) 2073 { 2074 2075 bzero(marker, sizeof(*marker)); 2076 marker->marker = true; 2077 } 2078 2079 Obj_Entry * 2080 globallist_curr(const Obj_Entry *obj) 2081 { 2082 2083 for (;;) { 2084 if (obj == NULL) 2085 return (NULL); 2086 if (!obj->marker) 2087 return (__DECONST(Obj_Entry *, obj)); 2088 obj = TAILQ_PREV(obj, obj_entry_q, next); 2089 } 2090 } 2091 2092 Obj_Entry * 2093 globallist_next(const Obj_Entry *obj) 2094 { 2095 2096 for (;;) { 2097 obj = TAILQ_NEXT(obj, next); 2098 if (obj == NULL) 2099 return (NULL); 2100 if (!obj->marker) 2101 return (__DECONST(Obj_Entry *, obj)); 2102 } 2103 } 2104 2105 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2106 static void 2107 hold_object(Obj_Entry *obj) 2108 { 2109 2110 obj->holdcount++; 2111 } 2112 2113 static void 2114 unhold_object(Obj_Entry *obj) 2115 { 2116 2117 assert(obj->holdcount > 0); 2118 if (--obj->holdcount == 0 && obj->unholdfree) 2119 release_object(obj); 2120 } 2121 2122 static void 2123 process_z(Obj_Entry *root) 2124 { 2125 const Objlist_Entry *elm; 2126 Obj_Entry *obj; 2127 2128 /* 2129 * Walk over object DAG and process every dependent object 2130 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2131 * to grow their own DAG. 2132 * 2133 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2134 * symlook_global() to work. 2135 * 2136 * For DF_1_NODELETE, the DAG should have its reference upped. 2137 */ 2138 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2139 obj = elm->obj; 2140 if (obj == NULL) 2141 continue; 2142 if (obj->z_nodelete && !obj->ref_nodel) { 2143 dbg("obj %s -z nodelete", obj->path); 2144 init_dag(obj); 2145 ref_dag(obj); 2146 obj->ref_nodel = true; 2147 } 2148 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2149 dbg("obj %s -z global", obj->path); 2150 objlist_push_tail(&list_global, obj); 2151 init_dag(obj); 2152 } 2153 } 2154 } 2155 /* 2156 * Initialize the dynamic linker. The argument is the address at which 2157 * the dynamic linker has been mapped into memory. The primary task of 2158 * this function is to relocate the dynamic linker. 2159 */ 2160 static void 2161 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2162 { 2163 Obj_Entry objtmp; /* Temporary rtld object */ 2164 const Elf_Ehdr *ehdr; 2165 const Elf_Dyn *dyn_rpath; 2166 const Elf_Dyn *dyn_soname; 2167 const Elf_Dyn *dyn_runpath; 2168 2169 #ifdef RTLD_INIT_PAGESIZES_EARLY 2170 /* The page size is required by the dynamic memory allocator. */ 2171 init_pagesizes(aux_info); 2172 #endif 2173 2174 /* 2175 * Conjure up an Obj_Entry structure for the dynamic linker. 2176 * 2177 * The "path" member can't be initialized yet because string constants 2178 * cannot yet be accessed. Below we will set it correctly. 2179 */ 2180 memset(&objtmp, 0, sizeof(objtmp)); 2181 objtmp.path = NULL; 2182 objtmp.rtld = true; 2183 objtmp.mapbase = mapbase; 2184 #ifdef PIC 2185 objtmp.relocbase = mapbase; 2186 #endif 2187 2188 objtmp.dynamic = rtld_dynamic(&objtmp); 2189 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2190 assert(objtmp.needed == NULL); 2191 #if !defined(__mips__) 2192 /* MIPS has a bogus DT_TEXTREL. */ 2193 assert(!objtmp.textrel); 2194 #endif 2195 /* 2196 * Temporarily put the dynamic linker entry into the object list, so 2197 * that symbols can be found. 2198 */ 2199 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2200 2201 ehdr = (Elf_Ehdr *)mapbase; 2202 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2203 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2204 2205 /* Initialize the object list. */ 2206 TAILQ_INIT(&obj_list); 2207 2208 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2209 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2210 2211 #ifndef RTLD_INIT_PAGESIZES_EARLY 2212 /* The page size is required by the dynamic memory allocator. */ 2213 init_pagesizes(aux_info); 2214 #endif 2215 2216 if (aux_info[AT_OSRELDATE] != NULL) 2217 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2218 2219 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2220 2221 /* Replace the path with a dynamically allocated copy. */ 2222 obj_rtld.path = xstrdup(ld_path_rtld); 2223 2224 r_debug.r_brk = r_debug_state; 2225 r_debug.r_state = RT_CONSISTENT; 2226 } 2227 2228 /* 2229 * Retrieve the array of supported page sizes. The kernel provides the page 2230 * sizes in increasing order. 2231 */ 2232 static void 2233 init_pagesizes(Elf_Auxinfo **aux_info) 2234 { 2235 static size_t psa[MAXPAGESIZES]; 2236 int mib[2]; 2237 size_t len, size; 2238 2239 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2240 NULL) { 2241 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2242 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2243 } else { 2244 len = 2; 2245 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2246 size = sizeof(psa); 2247 else { 2248 /* As a fallback, retrieve the base page size. */ 2249 size = sizeof(psa[0]); 2250 if (aux_info[AT_PAGESZ] != NULL) { 2251 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2252 goto psa_filled; 2253 } else { 2254 mib[0] = CTL_HW; 2255 mib[1] = HW_PAGESIZE; 2256 len = 2; 2257 } 2258 } 2259 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2260 _rtld_error("sysctl for hw.pagesize(s) failed"); 2261 rtld_die(); 2262 } 2263 psa_filled: 2264 pagesizes = psa; 2265 } 2266 npagesizes = size / sizeof(pagesizes[0]); 2267 /* Discard any invalid entries at the end of the array. */ 2268 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2269 npagesizes--; 2270 } 2271 2272 /* 2273 * Add the init functions from a needed object list (and its recursive 2274 * needed objects) to "list". This is not used directly; it is a helper 2275 * function for initlist_add_objects(). The write lock must be held 2276 * when this function is called. 2277 */ 2278 static void 2279 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2280 { 2281 /* Recursively process the successor needed objects. */ 2282 if (needed->next != NULL) 2283 initlist_add_neededs(needed->next, list); 2284 2285 /* Process the current needed object. */ 2286 if (needed->obj != NULL) 2287 initlist_add_objects(needed->obj, needed->obj, list); 2288 } 2289 2290 /* 2291 * Scan all of the DAGs rooted in the range of objects from "obj" to 2292 * "tail" and add their init functions to "list". This recurses over 2293 * the DAGs and ensure the proper init ordering such that each object's 2294 * needed libraries are initialized before the object itself. At the 2295 * same time, this function adds the objects to the global finalization 2296 * list "list_fini" in the opposite order. The write lock must be 2297 * held when this function is called. 2298 */ 2299 static void 2300 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2301 { 2302 Obj_Entry *nobj; 2303 2304 if (obj->init_scanned || obj->init_done) 2305 return; 2306 obj->init_scanned = true; 2307 2308 /* Recursively process the successor objects. */ 2309 nobj = globallist_next(obj); 2310 if (nobj != NULL && obj != tail) 2311 initlist_add_objects(nobj, tail, list); 2312 2313 /* Recursively process the needed objects. */ 2314 if (obj->needed != NULL) 2315 initlist_add_neededs(obj->needed, list); 2316 if (obj->needed_filtees != NULL) 2317 initlist_add_neededs(obj->needed_filtees, list); 2318 if (obj->needed_aux_filtees != NULL) 2319 initlist_add_neededs(obj->needed_aux_filtees, list); 2320 2321 /* Add the object to the init list. */ 2322 objlist_push_tail(list, obj); 2323 2324 /* Add the object to the global fini list in the reverse order. */ 2325 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2326 && !obj->on_fini_list) { 2327 objlist_push_head(&list_fini, obj); 2328 obj->on_fini_list = true; 2329 } 2330 } 2331 2332 #ifndef FPTR_TARGET 2333 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2334 #endif 2335 2336 static void 2337 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2338 { 2339 Needed_Entry *needed, *needed1; 2340 2341 for (needed = n; needed != NULL; needed = needed->next) { 2342 if (needed->obj != NULL) { 2343 dlclose_locked(needed->obj, lockstate); 2344 needed->obj = NULL; 2345 } 2346 } 2347 for (needed = n; needed != NULL; needed = needed1) { 2348 needed1 = needed->next; 2349 free(needed); 2350 } 2351 } 2352 2353 static void 2354 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2355 { 2356 2357 free_needed_filtees(obj->needed_filtees, lockstate); 2358 obj->needed_filtees = NULL; 2359 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2360 obj->needed_aux_filtees = NULL; 2361 obj->filtees_loaded = false; 2362 } 2363 2364 static void 2365 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2366 RtldLockState *lockstate) 2367 { 2368 2369 for (; needed != NULL; needed = needed->next) { 2370 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2371 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2372 RTLD_LOCAL, lockstate); 2373 } 2374 } 2375 2376 static void 2377 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2378 { 2379 2380 lock_restart_for_upgrade(lockstate); 2381 if (!obj->filtees_loaded) { 2382 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2383 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2384 obj->filtees_loaded = true; 2385 } 2386 } 2387 2388 static int 2389 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2390 { 2391 Obj_Entry *obj1; 2392 2393 for (; needed != NULL; needed = needed->next) { 2394 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2395 flags & ~RTLD_LO_NOLOAD); 2396 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2397 return (-1); 2398 } 2399 return (0); 2400 } 2401 2402 /* 2403 * Given a shared object, traverse its list of needed objects, and load 2404 * each of them. Returns 0 on success. Generates an error message and 2405 * returns -1 on failure. 2406 */ 2407 static int 2408 load_needed_objects(Obj_Entry *first, int flags) 2409 { 2410 Obj_Entry *obj; 2411 2412 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2413 if (obj->marker) 2414 continue; 2415 if (process_needed(obj, obj->needed, flags) == -1) 2416 return (-1); 2417 } 2418 return (0); 2419 } 2420 2421 static int 2422 load_preload_objects(void) 2423 { 2424 char *p = ld_preload; 2425 Obj_Entry *obj; 2426 static const char delim[] = " \t:;"; 2427 2428 if (p == NULL) 2429 return 0; 2430 2431 p += strspn(p, delim); 2432 while (*p != '\0') { 2433 size_t len = strcspn(p, delim); 2434 char savech; 2435 2436 savech = p[len]; 2437 p[len] = '\0'; 2438 obj = load_object(p, -1, NULL, 0); 2439 if (obj == NULL) 2440 return -1; /* XXX - cleanup */ 2441 obj->z_interpose = true; 2442 p[len] = savech; 2443 p += len; 2444 p += strspn(p, delim); 2445 } 2446 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2447 return 0; 2448 } 2449 2450 static const char * 2451 printable_path(const char *path) 2452 { 2453 2454 return (path == NULL ? "<unknown>" : path); 2455 } 2456 2457 /* 2458 * Load a shared object into memory, if it is not already loaded. The 2459 * object may be specified by name or by user-supplied file descriptor 2460 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2461 * duplicate is. 2462 * 2463 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2464 * on failure. 2465 */ 2466 static Obj_Entry * 2467 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2468 { 2469 Obj_Entry *obj; 2470 int fd; 2471 struct stat sb; 2472 char *path; 2473 2474 fd = -1; 2475 if (name != NULL) { 2476 TAILQ_FOREACH(obj, &obj_list, next) { 2477 if (obj->marker || obj->doomed) 2478 continue; 2479 if (object_match_name(obj, name)) 2480 return (obj); 2481 } 2482 2483 path = find_library(name, refobj, &fd); 2484 if (path == NULL) 2485 return (NULL); 2486 } else 2487 path = NULL; 2488 2489 if (fd >= 0) { 2490 /* 2491 * search_library_pathfds() opens a fresh file descriptor for the 2492 * library, so there is no need to dup(). 2493 */ 2494 } else if (fd_u == -1) { 2495 /* 2496 * If we didn't find a match by pathname, or the name is not 2497 * supplied, open the file and check again by device and inode. 2498 * This avoids false mismatches caused by multiple links or ".." 2499 * in pathnames. 2500 * 2501 * To avoid a race, we open the file and use fstat() rather than 2502 * using stat(). 2503 */ 2504 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2505 _rtld_error("Cannot open \"%s\"", path); 2506 free(path); 2507 return (NULL); 2508 } 2509 } else { 2510 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2511 if (fd == -1) { 2512 _rtld_error("Cannot dup fd"); 2513 free(path); 2514 return (NULL); 2515 } 2516 } 2517 if (fstat(fd, &sb) == -1) { 2518 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2519 close(fd); 2520 free(path); 2521 return NULL; 2522 } 2523 TAILQ_FOREACH(obj, &obj_list, next) { 2524 if (obj->marker || obj->doomed) 2525 continue; 2526 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2527 break; 2528 } 2529 if (obj != NULL && name != NULL) { 2530 object_add_name(obj, name); 2531 free(path); 2532 close(fd); 2533 return obj; 2534 } 2535 if (flags & RTLD_LO_NOLOAD) { 2536 free(path); 2537 close(fd); 2538 return (NULL); 2539 } 2540 2541 /* First use of this object, so we must map it in */ 2542 obj = do_load_object(fd, name, path, &sb, flags); 2543 if (obj == NULL) 2544 free(path); 2545 close(fd); 2546 2547 return obj; 2548 } 2549 2550 static Obj_Entry * 2551 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2552 int flags) 2553 { 2554 Obj_Entry *obj; 2555 struct statfs fs; 2556 2557 /* 2558 * but first, make sure that environment variables haven't been 2559 * used to circumvent the noexec flag on a filesystem. 2560 */ 2561 if (dangerous_ld_env) { 2562 if (fstatfs(fd, &fs) != 0) { 2563 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2564 return NULL; 2565 } 2566 if (fs.f_flags & MNT_NOEXEC) { 2567 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2568 return NULL; 2569 } 2570 } 2571 dbg("loading \"%s\"", printable_path(path)); 2572 obj = map_object(fd, printable_path(path), sbp); 2573 if (obj == NULL) 2574 return NULL; 2575 2576 /* 2577 * If DT_SONAME is present in the object, digest_dynamic2 already 2578 * added it to the object names. 2579 */ 2580 if (name != NULL) 2581 object_add_name(obj, name); 2582 obj->path = path; 2583 if (!digest_dynamic(obj, 0)) 2584 goto errp; 2585 if (obj->z_pie) { 2586 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2587 goto errp; 2588 } 2589 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2590 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2591 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2592 RTLD_LO_DLOPEN) { 2593 dbg("refusing to load non-loadable \"%s\"", obj->path); 2594 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2595 goto errp; 2596 } 2597 2598 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2599 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2600 obj_count++; 2601 obj_loads++; 2602 linkmap_add(obj); /* for GDB & dlinfo() */ 2603 max_stack_flags |= obj->stack_flags; 2604 2605 dbg(" %p .. %p: %s", obj->mapbase, 2606 obj->mapbase + obj->mapsize - 1, obj->path); 2607 if (obj->textrel) 2608 dbg(" WARNING: %s has impure text", obj->path); 2609 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2610 obj->path); 2611 2612 return (obj); 2613 2614 errp: 2615 munmap(obj->mapbase, obj->mapsize); 2616 obj_free(obj); 2617 return (NULL); 2618 } 2619 2620 static Obj_Entry * 2621 obj_from_addr(const void *addr) 2622 { 2623 Obj_Entry *obj; 2624 2625 TAILQ_FOREACH(obj, &obj_list, next) { 2626 if (obj->marker) 2627 continue; 2628 if (addr < (void *) obj->mapbase) 2629 continue; 2630 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2631 return obj; 2632 } 2633 return NULL; 2634 } 2635 2636 static void 2637 preinit_main(void) 2638 { 2639 Elf_Addr *preinit_addr; 2640 int index; 2641 2642 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2643 if (preinit_addr == NULL) 2644 return; 2645 2646 for (index = 0; index < obj_main->preinit_array_num; index++) { 2647 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2648 dbg("calling preinit function for %s at %p", obj_main->path, 2649 (void *)preinit_addr[index]); 2650 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2651 0, 0, obj_main->path); 2652 call_init_pointer(obj_main, preinit_addr[index]); 2653 } 2654 } 2655 } 2656 2657 /* 2658 * Call the finalization functions for each of the objects in "list" 2659 * belonging to the DAG of "root" and referenced once. If NULL "root" 2660 * is specified, every finalization function will be called regardless 2661 * of the reference count and the list elements won't be freed. All of 2662 * the objects are expected to have non-NULL fini functions. 2663 */ 2664 static void 2665 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2666 { 2667 Objlist_Entry *elm; 2668 char *saved_msg; 2669 Elf_Addr *fini_addr; 2670 int index; 2671 2672 assert(root == NULL || root->refcount == 1); 2673 2674 if (root != NULL) 2675 root->doomed = true; 2676 2677 /* 2678 * Preserve the current error message since a fini function might 2679 * call into the dynamic linker and overwrite it. 2680 */ 2681 saved_msg = errmsg_save(); 2682 do { 2683 STAILQ_FOREACH(elm, list, link) { 2684 if (root != NULL && (elm->obj->refcount != 1 || 2685 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2686 continue; 2687 /* Remove object from fini list to prevent recursive invocation. */ 2688 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2689 /* Ensure that new references cannot be acquired. */ 2690 elm->obj->doomed = true; 2691 2692 hold_object(elm->obj); 2693 lock_release(rtld_bind_lock, lockstate); 2694 /* 2695 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2696 * When this happens, DT_FINI_ARRAY is processed first. 2697 */ 2698 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2699 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2700 for (index = elm->obj->fini_array_num - 1; index >= 0; 2701 index--) { 2702 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2703 dbg("calling fini function for %s at %p", 2704 elm->obj->path, (void *)fini_addr[index]); 2705 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2706 (void *)fini_addr[index], 0, 0, elm->obj->path); 2707 call_initfini_pointer(elm->obj, fini_addr[index]); 2708 } 2709 } 2710 } 2711 if (elm->obj->fini != (Elf_Addr)NULL) { 2712 dbg("calling fini function for %s at %p", elm->obj->path, 2713 (void *)elm->obj->fini); 2714 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2715 0, 0, elm->obj->path); 2716 call_initfini_pointer(elm->obj, elm->obj->fini); 2717 } 2718 wlock_acquire(rtld_bind_lock, lockstate); 2719 unhold_object(elm->obj); 2720 /* No need to free anything if process is going down. */ 2721 if (root != NULL) 2722 free(elm); 2723 /* 2724 * We must restart the list traversal after every fini call 2725 * because a dlclose() call from the fini function or from 2726 * another thread might have modified the reference counts. 2727 */ 2728 break; 2729 } 2730 } while (elm != NULL); 2731 errmsg_restore(saved_msg); 2732 } 2733 2734 /* 2735 * Call the initialization functions for each of the objects in 2736 * "list". All of the objects are expected to have non-NULL init 2737 * functions. 2738 */ 2739 static void 2740 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2741 { 2742 Objlist_Entry *elm; 2743 Obj_Entry *obj; 2744 char *saved_msg; 2745 Elf_Addr *init_addr; 2746 void (*reg)(void (*)(void)); 2747 int index; 2748 2749 /* 2750 * Clean init_scanned flag so that objects can be rechecked and 2751 * possibly initialized earlier if any of vectors called below 2752 * cause the change by using dlopen. 2753 */ 2754 TAILQ_FOREACH(obj, &obj_list, next) { 2755 if (obj->marker) 2756 continue; 2757 obj->init_scanned = false; 2758 } 2759 2760 /* 2761 * Preserve the current error message since an init function might 2762 * call into the dynamic linker and overwrite it. 2763 */ 2764 saved_msg = errmsg_save(); 2765 STAILQ_FOREACH(elm, list, link) { 2766 if (elm->obj->init_done) /* Initialized early. */ 2767 continue; 2768 /* 2769 * Race: other thread might try to use this object before current 2770 * one completes the initialization. Not much can be done here 2771 * without better locking. 2772 */ 2773 elm->obj->init_done = true; 2774 hold_object(elm->obj); 2775 reg = NULL; 2776 if (elm->obj == obj_main && obj_main->crt_no_init) { 2777 reg = (void (*)(void (*)(void)))get_program_var_addr( 2778 "__libc_atexit", lockstate); 2779 } 2780 lock_release(rtld_bind_lock, lockstate); 2781 if (reg != NULL) { 2782 reg(rtld_exit); 2783 rtld_exit_ptr = rtld_nop_exit; 2784 } 2785 2786 /* 2787 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2788 * When this happens, DT_INIT is processed first. 2789 */ 2790 if (elm->obj->init != (Elf_Addr)NULL) { 2791 dbg("calling init function for %s at %p", elm->obj->path, 2792 (void *)elm->obj->init); 2793 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2794 0, 0, elm->obj->path); 2795 call_initfini_pointer(elm->obj, elm->obj->init); 2796 } 2797 init_addr = (Elf_Addr *)elm->obj->init_array; 2798 if (init_addr != NULL) { 2799 for (index = 0; index < elm->obj->init_array_num; index++) { 2800 if (init_addr[index] != 0 && init_addr[index] != 1) { 2801 dbg("calling init function for %s at %p", elm->obj->path, 2802 (void *)init_addr[index]); 2803 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2804 (void *)init_addr[index], 0, 0, elm->obj->path); 2805 call_init_pointer(elm->obj, init_addr[index]); 2806 } 2807 } 2808 } 2809 wlock_acquire(rtld_bind_lock, lockstate); 2810 unhold_object(elm->obj); 2811 } 2812 errmsg_restore(saved_msg); 2813 } 2814 2815 static void 2816 objlist_clear(Objlist *list) 2817 { 2818 Objlist_Entry *elm; 2819 2820 while (!STAILQ_EMPTY(list)) { 2821 elm = STAILQ_FIRST(list); 2822 STAILQ_REMOVE_HEAD(list, link); 2823 free(elm); 2824 } 2825 } 2826 2827 static Objlist_Entry * 2828 objlist_find(Objlist *list, const Obj_Entry *obj) 2829 { 2830 Objlist_Entry *elm; 2831 2832 STAILQ_FOREACH(elm, list, link) 2833 if (elm->obj == obj) 2834 return elm; 2835 return NULL; 2836 } 2837 2838 static void 2839 objlist_init(Objlist *list) 2840 { 2841 STAILQ_INIT(list); 2842 } 2843 2844 static void 2845 objlist_push_head(Objlist *list, Obj_Entry *obj) 2846 { 2847 Objlist_Entry *elm; 2848 2849 elm = NEW(Objlist_Entry); 2850 elm->obj = obj; 2851 STAILQ_INSERT_HEAD(list, elm, link); 2852 } 2853 2854 static void 2855 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2856 { 2857 Objlist_Entry *elm; 2858 2859 elm = NEW(Objlist_Entry); 2860 elm->obj = obj; 2861 STAILQ_INSERT_TAIL(list, elm, link); 2862 } 2863 2864 static void 2865 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2866 { 2867 Objlist_Entry *elm, *listelm; 2868 2869 STAILQ_FOREACH(listelm, list, link) { 2870 if (listelm->obj == listobj) 2871 break; 2872 } 2873 elm = NEW(Objlist_Entry); 2874 elm->obj = obj; 2875 if (listelm != NULL) 2876 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2877 else 2878 STAILQ_INSERT_TAIL(list, elm, link); 2879 } 2880 2881 static void 2882 objlist_remove(Objlist *list, Obj_Entry *obj) 2883 { 2884 Objlist_Entry *elm; 2885 2886 if ((elm = objlist_find(list, obj)) != NULL) { 2887 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2888 free(elm); 2889 } 2890 } 2891 2892 /* 2893 * Relocate dag rooted in the specified object. 2894 * Returns 0 on success, or -1 on failure. 2895 */ 2896 2897 static int 2898 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2899 int flags, RtldLockState *lockstate) 2900 { 2901 Objlist_Entry *elm; 2902 int error; 2903 2904 error = 0; 2905 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2906 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2907 lockstate); 2908 if (error == -1) 2909 break; 2910 } 2911 return (error); 2912 } 2913 2914 /* 2915 * Prepare for, or clean after, relocating an object marked with 2916 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2917 * segments are remapped read-write. After relocations are done, the 2918 * segment's permissions are returned back to the modes specified in 2919 * the phdrs. If any relocation happened, or always for wired 2920 * program, COW is triggered. 2921 */ 2922 static int 2923 reloc_textrel_prot(Obj_Entry *obj, bool before) 2924 { 2925 const Elf_Phdr *ph; 2926 void *base; 2927 size_t l, sz; 2928 int prot; 2929 2930 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2931 l--, ph++) { 2932 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2933 continue; 2934 base = obj->relocbase + trunc_page(ph->p_vaddr); 2935 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2936 trunc_page(ph->p_vaddr); 2937 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2938 if (mprotect(base, sz, prot) == -1) { 2939 _rtld_error("%s: Cannot write-%sable text segment: %s", 2940 obj->path, before ? "en" : "dis", 2941 rtld_strerror(errno)); 2942 return (-1); 2943 } 2944 } 2945 return (0); 2946 } 2947 2948 /* 2949 * Relocate single object. 2950 * Returns 0 on success, or -1 on failure. 2951 */ 2952 static int 2953 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2954 int flags, RtldLockState *lockstate) 2955 { 2956 2957 if (obj->relocated) 2958 return (0); 2959 obj->relocated = true; 2960 if (obj != rtldobj) 2961 dbg("relocating \"%s\"", obj->path); 2962 2963 if (obj->symtab == NULL || obj->strtab == NULL || 2964 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2965 _rtld_error("%s: Shared object has no run-time symbol table", 2966 obj->path); 2967 return (-1); 2968 } 2969 2970 /* There are relocations to the write-protected text segment. */ 2971 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2972 return (-1); 2973 2974 /* Process the non-PLT non-IFUNC relocations. */ 2975 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2976 return (-1); 2977 2978 /* Re-protected the text segment. */ 2979 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2980 return (-1); 2981 2982 /* Set the special PLT or GOT entries. */ 2983 init_pltgot(obj); 2984 2985 /* Process the PLT relocations. */ 2986 if (reloc_plt(obj, flags, lockstate) == -1) 2987 return (-1); 2988 /* Relocate the jump slots if we are doing immediate binding. */ 2989 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2990 lockstate) == -1) 2991 return (-1); 2992 2993 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2994 return (-1); 2995 2996 /* 2997 * Set up the magic number and version in the Obj_Entry. These 2998 * were checked in the crt1.o from the original ElfKit, so we 2999 * set them for backward compatibility. 3000 */ 3001 obj->magic = RTLD_MAGIC; 3002 obj->version = RTLD_VERSION; 3003 3004 return (0); 3005 } 3006 3007 /* 3008 * Relocate newly-loaded shared objects. The argument is a pointer to 3009 * the Obj_Entry for the first such object. All objects from the first 3010 * to the end of the list of objects are relocated. Returns 0 on success, 3011 * or -1 on failure. 3012 */ 3013 static int 3014 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3015 int flags, RtldLockState *lockstate) 3016 { 3017 Obj_Entry *obj; 3018 int error; 3019 3020 for (error = 0, obj = first; obj != NULL; 3021 obj = TAILQ_NEXT(obj, next)) { 3022 if (obj->marker) 3023 continue; 3024 error = relocate_object(obj, bind_now, rtldobj, flags, 3025 lockstate); 3026 if (error == -1) 3027 break; 3028 } 3029 return (error); 3030 } 3031 3032 /* 3033 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3034 * referencing STT_GNU_IFUNC symbols is postponed till the other 3035 * relocations are done. The indirect functions specified as 3036 * ifunc are allowed to call other symbols, so we need to have 3037 * objects relocated before asking for resolution from indirects. 3038 * 3039 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3040 * instead of the usual lazy handling of PLT slots. It is 3041 * consistent with how GNU does it. 3042 */ 3043 static int 3044 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3045 RtldLockState *lockstate) 3046 { 3047 3048 if (obj->ifuncs_resolved) 3049 return (0); 3050 obj->ifuncs_resolved = true; 3051 if (!obj->irelative && !obj->irelative_nonplt && 3052 !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3053 return (0); 3054 if (obj_disable_relro(obj) == -1 || 3055 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3056 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3057 lockstate) == -1) || 3058 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3059 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3060 obj_enforce_relro(obj) == -1) 3061 return (-1); 3062 return (0); 3063 } 3064 3065 static int 3066 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3067 RtldLockState *lockstate) 3068 { 3069 Objlist_Entry *elm; 3070 Obj_Entry *obj; 3071 3072 STAILQ_FOREACH(elm, list, link) { 3073 obj = elm->obj; 3074 if (obj->marker) 3075 continue; 3076 if (resolve_object_ifunc(obj, bind_now, flags, 3077 lockstate) == -1) 3078 return (-1); 3079 } 3080 return (0); 3081 } 3082 3083 /* 3084 * Cleanup procedure. It will be called (by the atexit mechanism) just 3085 * before the process exits. 3086 */ 3087 static void 3088 rtld_exit(void) 3089 { 3090 RtldLockState lockstate; 3091 3092 wlock_acquire(rtld_bind_lock, &lockstate); 3093 dbg("rtld_exit()"); 3094 objlist_call_fini(&list_fini, NULL, &lockstate); 3095 /* No need to remove the items from the list, since we are exiting. */ 3096 if (!libmap_disable) 3097 lm_fini(); 3098 lock_release(rtld_bind_lock, &lockstate); 3099 } 3100 3101 static void 3102 rtld_nop_exit(void) 3103 { 3104 } 3105 3106 /* 3107 * Iterate over a search path, translate each element, and invoke the 3108 * callback on the result. 3109 */ 3110 static void * 3111 path_enumerate(const char *path, path_enum_proc callback, 3112 const char *refobj_path, void *arg) 3113 { 3114 const char *trans; 3115 if (path == NULL) 3116 return (NULL); 3117 3118 path += strspn(path, ":;"); 3119 while (*path != '\0') { 3120 size_t len; 3121 char *res; 3122 3123 len = strcspn(path, ":;"); 3124 trans = lm_findn(refobj_path, path, len); 3125 if (trans) 3126 res = callback(trans, strlen(trans), arg); 3127 else 3128 res = callback(path, len, arg); 3129 3130 if (res != NULL) 3131 return (res); 3132 3133 path += len; 3134 path += strspn(path, ":;"); 3135 } 3136 3137 return (NULL); 3138 } 3139 3140 struct try_library_args { 3141 const char *name; 3142 size_t namelen; 3143 char *buffer; 3144 size_t buflen; 3145 int fd; 3146 }; 3147 3148 static void * 3149 try_library_path(const char *dir, size_t dirlen, void *param) 3150 { 3151 struct try_library_args *arg; 3152 int fd; 3153 3154 arg = param; 3155 if (*dir == '/' || trust) { 3156 char *pathname; 3157 3158 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3159 return (NULL); 3160 3161 pathname = arg->buffer; 3162 strncpy(pathname, dir, dirlen); 3163 pathname[dirlen] = '/'; 3164 strcpy(pathname + dirlen + 1, arg->name); 3165 3166 dbg(" Trying \"%s\"", pathname); 3167 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3168 if (fd >= 0) { 3169 dbg(" Opened \"%s\", fd %d", pathname, fd); 3170 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3171 strcpy(pathname, arg->buffer); 3172 arg->fd = fd; 3173 return (pathname); 3174 } else { 3175 dbg(" Failed to open \"%s\": %s", 3176 pathname, rtld_strerror(errno)); 3177 } 3178 } 3179 return (NULL); 3180 } 3181 3182 static char * 3183 search_library_path(const char *name, const char *path, 3184 const char *refobj_path, int *fdp) 3185 { 3186 char *p; 3187 struct try_library_args arg; 3188 3189 if (path == NULL) 3190 return NULL; 3191 3192 arg.name = name; 3193 arg.namelen = strlen(name); 3194 arg.buffer = xmalloc(PATH_MAX); 3195 arg.buflen = PATH_MAX; 3196 arg.fd = -1; 3197 3198 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3199 *fdp = arg.fd; 3200 3201 free(arg.buffer); 3202 3203 return (p); 3204 } 3205 3206 3207 /* 3208 * Finds the library with the given name using the directory descriptors 3209 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3210 * 3211 * Returns a freshly-opened close-on-exec file descriptor for the library, 3212 * or -1 if the library cannot be found. 3213 */ 3214 static char * 3215 search_library_pathfds(const char *name, const char *path, int *fdp) 3216 { 3217 char *envcopy, *fdstr, *found, *last_token; 3218 size_t len; 3219 int dirfd, fd; 3220 3221 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3222 3223 /* Don't load from user-specified libdirs into setuid binaries. */ 3224 if (!trust) 3225 return (NULL); 3226 3227 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3228 if (path == NULL) 3229 return (NULL); 3230 3231 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3232 if (name[0] == '/') { 3233 dbg("Absolute path (%s) passed to %s", name, __func__); 3234 return (NULL); 3235 } 3236 3237 /* 3238 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3239 * copy of the path, as strtok_r rewrites separator tokens 3240 * with '\0'. 3241 */ 3242 found = NULL; 3243 envcopy = xstrdup(path); 3244 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3245 fdstr = strtok_r(NULL, ":", &last_token)) { 3246 dirfd = parse_integer(fdstr); 3247 if (dirfd < 0) { 3248 _rtld_error("failed to parse directory FD: '%s'", 3249 fdstr); 3250 break; 3251 } 3252 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3253 if (fd >= 0) { 3254 *fdp = fd; 3255 len = strlen(fdstr) + strlen(name) + 3; 3256 found = xmalloc(len); 3257 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3258 _rtld_error("error generating '%d/%s'", 3259 dirfd, name); 3260 rtld_die(); 3261 } 3262 dbg("open('%s') => %d", found, fd); 3263 break; 3264 } 3265 } 3266 free(envcopy); 3267 3268 return (found); 3269 } 3270 3271 3272 int 3273 dlclose(void *handle) 3274 { 3275 RtldLockState lockstate; 3276 int error; 3277 3278 wlock_acquire(rtld_bind_lock, &lockstate); 3279 error = dlclose_locked(handle, &lockstate); 3280 lock_release(rtld_bind_lock, &lockstate); 3281 return (error); 3282 } 3283 3284 static int 3285 dlclose_locked(void *handle, RtldLockState *lockstate) 3286 { 3287 Obj_Entry *root; 3288 3289 root = dlcheck(handle); 3290 if (root == NULL) 3291 return -1; 3292 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3293 root->path); 3294 3295 /* Unreference the object and its dependencies. */ 3296 root->dl_refcount--; 3297 3298 if (root->refcount == 1) { 3299 /* 3300 * The object will be no longer referenced, so we must unload it. 3301 * First, call the fini functions. 3302 */ 3303 objlist_call_fini(&list_fini, root, lockstate); 3304 3305 unref_dag(root); 3306 3307 /* Finish cleaning up the newly-unreferenced objects. */ 3308 GDB_STATE(RT_DELETE,&root->linkmap); 3309 unload_object(root, lockstate); 3310 GDB_STATE(RT_CONSISTENT,NULL); 3311 } else 3312 unref_dag(root); 3313 3314 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3315 return 0; 3316 } 3317 3318 char * 3319 dlerror(void) 3320 { 3321 char *msg = error_message; 3322 error_message = NULL; 3323 return msg; 3324 } 3325 3326 /* 3327 * This function is deprecated and has no effect. 3328 */ 3329 void 3330 dllockinit(void *context, 3331 void *(*_lock_create)(void *context) __unused, 3332 void (*_rlock_acquire)(void *lock) __unused, 3333 void (*_wlock_acquire)(void *lock) __unused, 3334 void (*_lock_release)(void *lock) __unused, 3335 void (*_lock_destroy)(void *lock) __unused, 3336 void (*context_destroy)(void *context)) 3337 { 3338 static void *cur_context; 3339 static void (*cur_context_destroy)(void *); 3340 3341 /* Just destroy the context from the previous call, if necessary. */ 3342 if (cur_context_destroy != NULL) 3343 cur_context_destroy(cur_context); 3344 cur_context = context; 3345 cur_context_destroy = context_destroy; 3346 } 3347 3348 void * 3349 dlopen(const char *name, int mode) 3350 { 3351 3352 return (rtld_dlopen(name, -1, mode)); 3353 } 3354 3355 void * 3356 fdlopen(int fd, int mode) 3357 { 3358 3359 return (rtld_dlopen(NULL, fd, mode)); 3360 } 3361 3362 static void * 3363 rtld_dlopen(const char *name, int fd, int mode) 3364 { 3365 RtldLockState lockstate; 3366 int lo_flags; 3367 3368 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3369 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3370 if (ld_tracing != NULL) { 3371 rlock_acquire(rtld_bind_lock, &lockstate); 3372 if (sigsetjmp(lockstate.env, 0) != 0) 3373 lock_upgrade(rtld_bind_lock, &lockstate); 3374 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3375 lock_release(rtld_bind_lock, &lockstate); 3376 } 3377 lo_flags = RTLD_LO_DLOPEN; 3378 if (mode & RTLD_NODELETE) 3379 lo_flags |= RTLD_LO_NODELETE; 3380 if (mode & RTLD_NOLOAD) 3381 lo_flags |= RTLD_LO_NOLOAD; 3382 if (mode & RTLD_DEEPBIND) 3383 lo_flags |= RTLD_LO_DEEPBIND; 3384 if (ld_tracing != NULL) 3385 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3386 3387 return (dlopen_object(name, fd, obj_main, lo_flags, 3388 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3389 } 3390 3391 static void 3392 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3393 { 3394 3395 obj->dl_refcount--; 3396 unref_dag(obj); 3397 if (obj->refcount == 0) 3398 unload_object(obj, lockstate); 3399 } 3400 3401 static Obj_Entry * 3402 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3403 int mode, RtldLockState *lockstate) 3404 { 3405 Obj_Entry *old_obj_tail; 3406 Obj_Entry *obj; 3407 Objlist initlist; 3408 RtldLockState mlockstate; 3409 int result; 3410 3411 objlist_init(&initlist); 3412 3413 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3414 wlock_acquire(rtld_bind_lock, &mlockstate); 3415 lockstate = &mlockstate; 3416 } 3417 GDB_STATE(RT_ADD,NULL); 3418 3419 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3420 obj = NULL; 3421 if (name == NULL && fd == -1) { 3422 obj = obj_main; 3423 obj->refcount++; 3424 } else { 3425 obj = load_object(name, fd, refobj, lo_flags); 3426 } 3427 3428 if (obj) { 3429 obj->dl_refcount++; 3430 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3431 objlist_push_tail(&list_global, obj); 3432 if (globallist_next(old_obj_tail) != NULL) { 3433 /* We loaded something new. */ 3434 assert(globallist_next(old_obj_tail) == obj); 3435 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3436 obj->symbolic = true; 3437 result = 0; 3438 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3439 obj->static_tls && !allocate_tls_offset(obj)) { 3440 _rtld_error("%s: No space available " 3441 "for static Thread Local Storage", obj->path); 3442 result = -1; 3443 } 3444 if (result != -1) 3445 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3446 RTLD_LO_EARLY | RTLD_LO_IGNSTLS)); 3447 init_dag(obj); 3448 ref_dag(obj); 3449 if (result != -1) 3450 result = rtld_verify_versions(&obj->dagmembers); 3451 if (result != -1 && ld_tracing) 3452 goto trace; 3453 if (result == -1 || relocate_object_dag(obj, 3454 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3455 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3456 lockstate) == -1) { 3457 dlopen_cleanup(obj, lockstate); 3458 obj = NULL; 3459 } else if (lo_flags & RTLD_LO_EARLY) { 3460 /* 3461 * Do not call the init functions for early loaded 3462 * filtees. The image is still not initialized enough 3463 * for them to work. 3464 * 3465 * Our object is found by the global object list and 3466 * will be ordered among all init calls done right 3467 * before transferring control to main. 3468 */ 3469 } else { 3470 /* Make list of init functions to call. */ 3471 initlist_add_objects(obj, obj, &initlist); 3472 } 3473 /* 3474 * Process all no_delete or global objects here, given 3475 * them own DAGs to prevent their dependencies from being 3476 * unloaded. This has to be done after we have loaded all 3477 * of the dependencies, so that we do not miss any. 3478 */ 3479 if (obj != NULL) 3480 process_z(obj); 3481 } else { 3482 /* 3483 * Bump the reference counts for objects on this DAG. If 3484 * this is the first dlopen() call for the object that was 3485 * already loaded as a dependency, initialize the dag 3486 * starting at it. 3487 */ 3488 init_dag(obj); 3489 ref_dag(obj); 3490 3491 if ((lo_flags & RTLD_LO_TRACE) != 0) 3492 goto trace; 3493 } 3494 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3495 obj->z_nodelete) && !obj->ref_nodel) { 3496 dbg("obj %s nodelete", obj->path); 3497 ref_dag(obj); 3498 obj->z_nodelete = obj->ref_nodel = true; 3499 } 3500 } 3501 3502 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3503 name); 3504 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3505 3506 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3507 map_stacks_exec(lockstate); 3508 if (obj != NULL) 3509 distribute_static_tls(&initlist, lockstate); 3510 } 3511 3512 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3513 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3514 lockstate) == -1) { 3515 objlist_clear(&initlist); 3516 dlopen_cleanup(obj, lockstate); 3517 if (lockstate == &mlockstate) 3518 lock_release(rtld_bind_lock, lockstate); 3519 return (NULL); 3520 } 3521 3522 if (!(lo_flags & RTLD_LO_EARLY)) { 3523 /* Call the init functions. */ 3524 objlist_call_init(&initlist, lockstate); 3525 } 3526 objlist_clear(&initlist); 3527 if (lockstate == &mlockstate) 3528 lock_release(rtld_bind_lock, lockstate); 3529 return obj; 3530 trace: 3531 trace_loaded_objects(obj); 3532 if (lockstate == &mlockstate) 3533 lock_release(rtld_bind_lock, lockstate); 3534 exit(0); 3535 } 3536 3537 static void * 3538 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3539 int flags) 3540 { 3541 DoneList donelist; 3542 const Obj_Entry *obj, *defobj; 3543 const Elf_Sym *def; 3544 SymLook req; 3545 RtldLockState lockstate; 3546 tls_index ti; 3547 void *sym; 3548 int res; 3549 3550 def = NULL; 3551 defobj = NULL; 3552 symlook_init(&req, name); 3553 req.ventry = ve; 3554 req.flags = flags | SYMLOOK_IN_PLT; 3555 req.lockstate = &lockstate; 3556 3557 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3558 rlock_acquire(rtld_bind_lock, &lockstate); 3559 if (sigsetjmp(lockstate.env, 0) != 0) 3560 lock_upgrade(rtld_bind_lock, &lockstate); 3561 if (handle == NULL || handle == RTLD_NEXT || 3562 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3563 3564 if ((obj = obj_from_addr(retaddr)) == NULL) { 3565 _rtld_error("Cannot determine caller's shared object"); 3566 lock_release(rtld_bind_lock, &lockstate); 3567 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3568 return NULL; 3569 } 3570 if (handle == NULL) { /* Just the caller's shared object. */ 3571 res = symlook_obj(&req, obj); 3572 if (res == 0) { 3573 def = req.sym_out; 3574 defobj = req.defobj_out; 3575 } 3576 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3577 handle == RTLD_SELF) { /* ... caller included */ 3578 if (handle == RTLD_NEXT) 3579 obj = globallist_next(obj); 3580 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3581 if (obj->marker) 3582 continue; 3583 res = symlook_obj(&req, obj); 3584 if (res == 0) { 3585 if (def == NULL || 3586 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3587 def = req.sym_out; 3588 defobj = req.defobj_out; 3589 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3590 break; 3591 } 3592 } 3593 } 3594 /* 3595 * Search the dynamic linker itself, and possibly resolve the 3596 * symbol from there. This is how the application links to 3597 * dynamic linker services such as dlopen. 3598 */ 3599 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3600 res = symlook_obj(&req, &obj_rtld); 3601 if (res == 0) { 3602 def = req.sym_out; 3603 defobj = req.defobj_out; 3604 } 3605 } 3606 } else { 3607 assert(handle == RTLD_DEFAULT); 3608 res = symlook_default(&req, obj); 3609 if (res == 0) { 3610 defobj = req.defobj_out; 3611 def = req.sym_out; 3612 } 3613 } 3614 } else { 3615 if ((obj = dlcheck(handle)) == NULL) { 3616 lock_release(rtld_bind_lock, &lockstate); 3617 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3618 return NULL; 3619 } 3620 3621 donelist_init(&donelist); 3622 if (obj->mainprog) { 3623 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3624 res = symlook_global(&req, &donelist); 3625 if (res == 0) { 3626 def = req.sym_out; 3627 defobj = req.defobj_out; 3628 } 3629 /* 3630 * Search the dynamic linker itself, and possibly resolve the 3631 * symbol from there. This is how the application links to 3632 * dynamic linker services such as dlopen. 3633 */ 3634 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3635 res = symlook_obj(&req, &obj_rtld); 3636 if (res == 0) { 3637 def = req.sym_out; 3638 defobj = req.defobj_out; 3639 } 3640 } 3641 } 3642 else { 3643 /* Search the whole DAG rooted at the given object. */ 3644 res = symlook_list(&req, &obj->dagmembers, &donelist); 3645 if (res == 0) { 3646 def = req.sym_out; 3647 defobj = req.defobj_out; 3648 } 3649 } 3650 } 3651 3652 if (def != NULL) { 3653 lock_release(rtld_bind_lock, &lockstate); 3654 3655 /* 3656 * The value required by the caller is derived from the value 3657 * of the symbol. this is simply the relocated value of the 3658 * symbol. 3659 */ 3660 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3661 sym = make_function_pointer(def, defobj); 3662 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3663 sym = rtld_resolve_ifunc(defobj, def); 3664 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3665 ti.ti_module = defobj->tlsindex; 3666 ti.ti_offset = def->st_value; 3667 sym = __tls_get_addr(&ti); 3668 } else 3669 sym = defobj->relocbase + def->st_value; 3670 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3671 return (sym); 3672 } 3673 3674 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3675 ve != NULL ? ve->name : ""); 3676 lock_release(rtld_bind_lock, &lockstate); 3677 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3678 return NULL; 3679 } 3680 3681 void * 3682 dlsym(void *handle, const char *name) 3683 { 3684 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3685 SYMLOOK_DLSYM); 3686 } 3687 3688 dlfunc_t 3689 dlfunc(void *handle, const char *name) 3690 { 3691 union { 3692 void *d; 3693 dlfunc_t f; 3694 } rv; 3695 3696 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3697 SYMLOOK_DLSYM); 3698 return (rv.f); 3699 } 3700 3701 void * 3702 dlvsym(void *handle, const char *name, const char *version) 3703 { 3704 Ver_Entry ventry; 3705 3706 ventry.name = version; 3707 ventry.file = NULL; 3708 ventry.hash = elf_hash(version); 3709 ventry.flags= 0; 3710 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3711 SYMLOOK_DLSYM); 3712 } 3713 3714 int 3715 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3716 { 3717 const Obj_Entry *obj; 3718 RtldLockState lockstate; 3719 3720 rlock_acquire(rtld_bind_lock, &lockstate); 3721 obj = obj_from_addr(addr); 3722 if (obj == NULL) { 3723 _rtld_error("No shared object contains address"); 3724 lock_release(rtld_bind_lock, &lockstate); 3725 return (0); 3726 } 3727 rtld_fill_dl_phdr_info(obj, phdr_info); 3728 lock_release(rtld_bind_lock, &lockstate); 3729 return (1); 3730 } 3731 3732 int 3733 dladdr(const void *addr, Dl_info *info) 3734 { 3735 const Obj_Entry *obj; 3736 const Elf_Sym *def; 3737 void *symbol_addr; 3738 unsigned long symoffset; 3739 RtldLockState lockstate; 3740 3741 rlock_acquire(rtld_bind_lock, &lockstate); 3742 obj = obj_from_addr(addr); 3743 if (obj == NULL) { 3744 _rtld_error("No shared object contains address"); 3745 lock_release(rtld_bind_lock, &lockstate); 3746 return 0; 3747 } 3748 info->dli_fname = obj->path; 3749 info->dli_fbase = obj->mapbase; 3750 info->dli_saddr = (void *)0; 3751 info->dli_sname = NULL; 3752 3753 /* 3754 * Walk the symbol list looking for the symbol whose address is 3755 * closest to the address sent in. 3756 */ 3757 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3758 def = obj->symtab + symoffset; 3759 3760 /* 3761 * For skip the symbol if st_shndx is either SHN_UNDEF or 3762 * SHN_COMMON. 3763 */ 3764 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3765 continue; 3766 3767 /* 3768 * If the symbol is greater than the specified address, or if it 3769 * is further away from addr than the current nearest symbol, 3770 * then reject it. 3771 */ 3772 symbol_addr = obj->relocbase + def->st_value; 3773 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3774 continue; 3775 3776 /* Update our idea of the nearest symbol. */ 3777 info->dli_sname = obj->strtab + def->st_name; 3778 info->dli_saddr = symbol_addr; 3779 3780 /* Exact match? */ 3781 if (info->dli_saddr == addr) 3782 break; 3783 } 3784 lock_release(rtld_bind_lock, &lockstate); 3785 return 1; 3786 } 3787 3788 int 3789 dlinfo(void *handle, int request, void *p) 3790 { 3791 const Obj_Entry *obj; 3792 RtldLockState lockstate; 3793 int error; 3794 3795 rlock_acquire(rtld_bind_lock, &lockstate); 3796 3797 if (handle == NULL || handle == RTLD_SELF) { 3798 void *retaddr; 3799 3800 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3801 if ((obj = obj_from_addr(retaddr)) == NULL) 3802 _rtld_error("Cannot determine caller's shared object"); 3803 } else 3804 obj = dlcheck(handle); 3805 3806 if (obj == NULL) { 3807 lock_release(rtld_bind_lock, &lockstate); 3808 return (-1); 3809 } 3810 3811 error = 0; 3812 switch (request) { 3813 case RTLD_DI_LINKMAP: 3814 *((struct link_map const **)p) = &obj->linkmap; 3815 break; 3816 case RTLD_DI_ORIGIN: 3817 error = rtld_dirname(obj->path, p); 3818 break; 3819 3820 case RTLD_DI_SERINFOSIZE: 3821 case RTLD_DI_SERINFO: 3822 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3823 break; 3824 3825 default: 3826 _rtld_error("Invalid request %d passed to dlinfo()", request); 3827 error = -1; 3828 } 3829 3830 lock_release(rtld_bind_lock, &lockstate); 3831 3832 return (error); 3833 } 3834 3835 static void 3836 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3837 { 3838 3839 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3840 phdr_info->dlpi_name = obj->path; 3841 phdr_info->dlpi_phdr = obj->phdr; 3842 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3843 phdr_info->dlpi_tls_modid = obj->tlsindex; 3844 phdr_info->dlpi_tls_data = obj->tlsinit; 3845 phdr_info->dlpi_adds = obj_loads; 3846 phdr_info->dlpi_subs = obj_loads - obj_count; 3847 } 3848 3849 int 3850 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3851 { 3852 struct dl_phdr_info phdr_info; 3853 Obj_Entry *obj, marker; 3854 RtldLockState bind_lockstate, phdr_lockstate; 3855 int error; 3856 3857 init_marker(&marker); 3858 error = 0; 3859 3860 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3861 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3862 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3863 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3864 rtld_fill_dl_phdr_info(obj, &phdr_info); 3865 hold_object(obj); 3866 lock_release(rtld_bind_lock, &bind_lockstate); 3867 3868 error = callback(&phdr_info, sizeof phdr_info, param); 3869 3870 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3871 unhold_object(obj); 3872 obj = globallist_next(&marker); 3873 TAILQ_REMOVE(&obj_list, &marker, next); 3874 if (error != 0) { 3875 lock_release(rtld_bind_lock, &bind_lockstate); 3876 lock_release(rtld_phdr_lock, &phdr_lockstate); 3877 return (error); 3878 } 3879 } 3880 3881 if (error == 0) { 3882 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3883 lock_release(rtld_bind_lock, &bind_lockstate); 3884 error = callback(&phdr_info, sizeof(phdr_info), param); 3885 } 3886 lock_release(rtld_phdr_lock, &phdr_lockstate); 3887 return (error); 3888 } 3889 3890 static void * 3891 fill_search_info(const char *dir, size_t dirlen, void *param) 3892 { 3893 struct fill_search_info_args *arg; 3894 3895 arg = param; 3896 3897 if (arg->request == RTLD_DI_SERINFOSIZE) { 3898 arg->serinfo->dls_cnt ++; 3899 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3900 } else { 3901 struct dl_serpath *s_entry; 3902 3903 s_entry = arg->serpath; 3904 s_entry->dls_name = arg->strspace; 3905 s_entry->dls_flags = arg->flags; 3906 3907 strncpy(arg->strspace, dir, dirlen); 3908 arg->strspace[dirlen] = '\0'; 3909 3910 arg->strspace += dirlen + 1; 3911 arg->serpath++; 3912 } 3913 3914 return (NULL); 3915 } 3916 3917 static int 3918 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3919 { 3920 struct dl_serinfo _info; 3921 struct fill_search_info_args args; 3922 3923 args.request = RTLD_DI_SERINFOSIZE; 3924 args.serinfo = &_info; 3925 3926 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3927 _info.dls_cnt = 0; 3928 3929 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3930 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3931 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3932 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3933 if (!obj->z_nodeflib) 3934 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3935 3936 3937 if (request == RTLD_DI_SERINFOSIZE) { 3938 info->dls_size = _info.dls_size; 3939 info->dls_cnt = _info.dls_cnt; 3940 return (0); 3941 } 3942 3943 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3944 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3945 return (-1); 3946 } 3947 3948 args.request = RTLD_DI_SERINFO; 3949 args.serinfo = info; 3950 args.serpath = &info->dls_serpath[0]; 3951 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3952 3953 args.flags = LA_SER_RUNPATH; 3954 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3955 return (-1); 3956 3957 args.flags = LA_SER_LIBPATH; 3958 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3959 return (-1); 3960 3961 args.flags = LA_SER_RUNPATH; 3962 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3963 return (-1); 3964 3965 args.flags = LA_SER_CONFIG; 3966 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3967 != NULL) 3968 return (-1); 3969 3970 args.flags = LA_SER_DEFAULT; 3971 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3972 fill_search_info, NULL, &args) != NULL) 3973 return (-1); 3974 return (0); 3975 } 3976 3977 static int 3978 rtld_dirname(const char *path, char *bname) 3979 { 3980 const char *endp; 3981 3982 /* Empty or NULL string gets treated as "." */ 3983 if (path == NULL || *path == '\0') { 3984 bname[0] = '.'; 3985 bname[1] = '\0'; 3986 return (0); 3987 } 3988 3989 /* Strip trailing slashes */ 3990 endp = path + strlen(path) - 1; 3991 while (endp > path && *endp == '/') 3992 endp--; 3993 3994 /* Find the start of the dir */ 3995 while (endp > path && *endp != '/') 3996 endp--; 3997 3998 /* Either the dir is "/" or there are no slashes */ 3999 if (endp == path) { 4000 bname[0] = *endp == '/' ? '/' : '.'; 4001 bname[1] = '\0'; 4002 return (0); 4003 } else { 4004 do { 4005 endp--; 4006 } while (endp > path && *endp == '/'); 4007 } 4008 4009 if (endp - path + 2 > PATH_MAX) 4010 { 4011 _rtld_error("Filename is too long: %s", path); 4012 return(-1); 4013 } 4014 4015 strncpy(bname, path, endp - path + 1); 4016 bname[endp - path + 1] = '\0'; 4017 return (0); 4018 } 4019 4020 static int 4021 rtld_dirname_abs(const char *path, char *base) 4022 { 4023 char *last; 4024 4025 if (realpath(path, base) == NULL) { 4026 _rtld_error("realpath \"%s\" failed (%s)", path, 4027 rtld_strerror(errno)); 4028 return (-1); 4029 } 4030 dbg("%s -> %s", path, base); 4031 last = strrchr(base, '/'); 4032 if (last == NULL) { 4033 _rtld_error("non-abs result from realpath \"%s\"", path); 4034 return (-1); 4035 } 4036 if (last != base) 4037 *last = '\0'; 4038 return (0); 4039 } 4040 4041 static void 4042 linkmap_add(Obj_Entry *obj) 4043 { 4044 struct link_map *l, *prev; 4045 4046 l = &obj->linkmap; 4047 l->l_name = obj->path; 4048 l->l_base = obj->mapbase; 4049 l->l_ld = obj->dynamic; 4050 l->l_addr = obj->relocbase; 4051 4052 if (r_debug.r_map == NULL) { 4053 r_debug.r_map = l; 4054 return; 4055 } 4056 4057 /* 4058 * Scan to the end of the list, but not past the entry for the 4059 * dynamic linker, which we want to keep at the very end. 4060 */ 4061 for (prev = r_debug.r_map; 4062 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4063 prev = prev->l_next) 4064 ; 4065 4066 /* Link in the new entry. */ 4067 l->l_prev = prev; 4068 l->l_next = prev->l_next; 4069 if (l->l_next != NULL) 4070 l->l_next->l_prev = l; 4071 prev->l_next = l; 4072 } 4073 4074 static void 4075 linkmap_delete(Obj_Entry *obj) 4076 { 4077 struct link_map *l; 4078 4079 l = &obj->linkmap; 4080 if (l->l_prev == NULL) { 4081 if ((r_debug.r_map = l->l_next) != NULL) 4082 l->l_next->l_prev = NULL; 4083 return; 4084 } 4085 4086 if ((l->l_prev->l_next = l->l_next) != NULL) 4087 l->l_next->l_prev = l->l_prev; 4088 } 4089 4090 /* 4091 * Function for the debugger to set a breakpoint on to gain control. 4092 * 4093 * The two parameters allow the debugger to easily find and determine 4094 * what the runtime loader is doing and to whom it is doing it. 4095 * 4096 * When the loadhook trap is hit (r_debug_state, set at program 4097 * initialization), the arguments can be found on the stack: 4098 * 4099 * +8 struct link_map *m 4100 * +4 struct r_debug *rd 4101 * +0 RetAddr 4102 */ 4103 void 4104 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4105 { 4106 /* 4107 * The following is a hack to force the compiler to emit calls to 4108 * this function, even when optimizing. If the function is empty, 4109 * the compiler is not obliged to emit any code for calls to it, 4110 * even when marked __noinline. However, gdb depends on those 4111 * calls being made. 4112 */ 4113 __compiler_membar(); 4114 } 4115 4116 /* 4117 * A function called after init routines have completed. This can be used to 4118 * break before a program's entry routine is called, and can be used when 4119 * main is not available in the symbol table. 4120 */ 4121 void 4122 _r_debug_postinit(struct link_map *m __unused) 4123 { 4124 4125 /* See r_debug_state(). */ 4126 __compiler_membar(); 4127 } 4128 4129 static void 4130 release_object(Obj_Entry *obj) 4131 { 4132 4133 if (obj->holdcount > 0) { 4134 obj->unholdfree = true; 4135 return; 4136 } 4137 munmap(obj->mapbase, obj->mapsize); 4138 linkmap_delete(obj); 4139 obj_free(obj); 4140 } 4141 4142 /* 4143 * Get address of the pointer variable in the main program. 4144 * Prefer non-weak symbol over the weak one. 4145 */ 4146 static const void ** 4147 get_program_var_addr(const char *name, RtldLockState *lockstate) 4148 { 4149 SymLook req; 4150 DoneList donelist; 4151 4152 symlook_init(&req, name); 4153 req.lockstate = lockstate; 4154 donelist_init(&donelist); 4155 if (symlook_global(&req, &donelist) != 0) 4156 return (NULL); 4157 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4158 return ((const void **)make_function_pointer(req.sym_out, 4159 req.defobj_out)); 4160 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4161 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4162 else 4163 return ((const void **)(req.defobj_out->relocbase + 4164 req.sym_out->st_value)); 4165 } 4166 4167 /* 4168 * Set a pointer variable in the main program to the given value. This 4169 * is used to set key variables such as "environ" before any of the 4170 * init functions are called. 4171 */ 4172 static void 4173 set_program_var(const char *name, const void *value) 4174 { 4175 const void **addr; 4176 4177 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4178 dbg("\"%s\": *%p <-- %p", name, addr, value); 4179 *addr = value; 4180 } 4181 } 4182 4183 /* 4184 * Search the global objects, including dependencies and main object, 4185 * for the given symbol. 4186 */ 4187 static int 4188 symlook_global(SymLook *req, DoneList *donelist) 4189 { 4190 SymLook req1; 4191 const Objlist_Entry *elm; 4192 int res; 4193 4194 symlook_init_from_req(&req1, req); 4195 4196 /* Search all objects loaded at program start up. */ 4197 if (req->defobj_out == NULL || 4198 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4199 res = symlook_list(&req1, &list_main, donelist); 4200 if (res == 0 && (req->defobj_out == NULL || 4201 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4202 req->sym_out = req1.sym_out; 4203 req->defobj_out = req1.defobj_out; 4204 assert(req->defobj_out != NULL); 4205 } 4206 } 4207 4208 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4209 STAILQ_FOREACH(elm, &list_global, link) { 4210 if (req->defobj_out != NULL && 4211 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4212 break; 4213 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4214 if (res == 0 && (req->defobj_out == NULL || 4215 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4216 req->sym_out = req1.sym_out; 4217 req->defobj_out = req1.defobj_out; 4218 assert(req->defobj_out != NULL); 4219 } 4220 } 4221 4222 return (req->sym_out != NULL ? 0 : ESRCH); 4223 } 4224 4225 /* 4226 * Given a symbol name in a referencing object, find the corresponding 4227 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4228 * no definition was found. Returns a pointer to the Obj_Entry of the 4229 * defining object via the reference parameter DEFOBJ_OUT. 4230 */ 4231 static int 4232 symlook_default(SymLook *req, const Obj_Entry *refobj) 4233 { 4234 DoneList donelist; 4235 const Objlist_Entry *elm; 4236 SymLook req1; 4237 int res; 4238 4239 donelist_init(&donelist); 4240 symlook_init_from_req(&req1, req); 4241 4242 /* 4243 * Look first in the referencing object if linked symbolically, 4244 * and similarly handle protected symbols. 4245 */ 4246 res = symlook_obj(&req1, refobj); 4247 if (res == 0 && (refobj->symbolic || 4248 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4249 req->sym_out = req1.sym_out; 4250 req->defobj_out = req1.defobj_out; 4251 assert(req->defobj_out != NULL); 4252 } 4253 if (refobj->symbolic || req->defobj_out != NULL) 4254 donelist_check(&donelist, refobj); 4255 4256 symlook_global(req, &donelist); 4257 4258 /* Search all dlopened DAGs containing the referencing object. */ 4259 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4260 if (req->sym_out != NULL && 4261 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4262 break; 4263 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4264 if (res == 0 && (req->sym_out == NULL || 4265 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4266 req->sym_out = req1.sym_out; 4267 req->defobj_out = req1.defobj_out; 4268 assert(req->defobj_out != NULL); 4269 } 4270 } 4271 4272 /* 4273 * Search the dynamic linker itself, and possibly resolve the 4274 * symbol from there. This is how the application links to 4275 * dynamic linker services such as dlopen. 4276 */ 4277 if (req->sym_out == NULL || 4278 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4279 res = symlook_obj(&req1, &obj_rtld); 4280 if (res == 0) { 4281 req->sym_out = req1.sym_out; 4282 req->defobj_out = req1.defobj_out; 4283 assert(req->defobj_out != NULL); 4284 } 4285 } 4286 4287 return (req->sym_out != NULL ? 0 : ESRCH); 4288 } 4289 4290 static int 4291 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4292 { 4293 const Elf_Sym *def; 4294 const Obj_Entry *defobj; 4295 const Objlist_Entry *elm; 4296 SymLook req1; 4297 int res; 4298 4299 def = NULL; 4300 defobj = NULL; 4301 STAILQ_FOREACH(elm, objlist, link) { 4302 if (donelist_check(dlp, elm->obj)) 4303 continue; 4304 symlook_init_from_req(&req1, req); 4305 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4306 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4307 def = req1.sym_out; 4308 defobj = req1.defobj_out; 4309 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4310 break; 4311 } 4312 } 4313 } 4314 if (def != NULL) { 4315 req->sym_out = def; 4316 req->defobj_out = defobj; 4317 return (0); 4318 } 4319 return (ESRCH); 4320 } 4321 4322 /* 4323 * Search the chain of DAGS cointed to by the given Needed_Entry 4324 * for a symbol of the given name. Each DAG is scanned completely 4325 * before advancing to the next one. Returns a pointer to the symbol, 4326 * or NULL if no definition was found. 4327 */ 4328 static int 4329 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4330 { 4331 const Elf_Sym *def; 4332 const Needed_Entry *n; 4333 const Obj_Entry *defobj; 4334 SymLook req1; 4335 int res; 4336 4337 def = NULL; 4338 defobj = NULL; 4339 symlook_init_from_req(&req1, req); 4340 for (n = needed; n != NULL; n = n->next) { 4341 if (n->obj == NULL || 4342 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4343 continue; 4344 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4345 def = req1.sym_out; 4346 defobj = req1.defobj_out; 4347 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4348 break; 4349 } 4350 } 4351 if (def != NULL) { 4352 req->sym_out = def; 4353 req->defobj_out = defobj; 4354 return (0); 4355 } 4356 return (ESRCH); 4357 } 4358 4359 /* 4360 * Search the symbol table of a single shared object for a symbol of 4361 * the given name and version, if requested. Returns a pointer to the 4362 * symbol, or NULL if no definition was found. If the object is 4363 * filter, return filtered symbol from filtee. 4364 * 4365 * The symbol's hash value is passed in for efficiency reasons; that 4366 * eliminates many recomputations of the hash value. 4367 */ 4368 int 4369 symlook_obj(SymLook *req, const Obj_Entry *obj) 4370 { 4371 DoneList donelist; 4372 SymLook req1; 4373 int flags, res, mres; 4374 4375 /* 4376 * If there is at least one valid hash at this point, we prefer to 4377 * use the faster GNU version if available. 4378 */ 4379 if (obj->valid_hash_gnu) 4380 mres = symlook_obj1_gnu(req, obj); 4381 else if (obj->valid_hash_sysv) 4382 mres = symlook_obj1_sysv(req, obj); 4383 else 4384 return (EINVAL); 4385 4386 if (mres == 0) { 4387 if (obj->needed_filtees != NULL) { 4388 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4389 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4390 donelist_init(&donelist); 4391 symlook_init_from_req(&req1, req); 4392 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4393 if (res == 0) { 4394 req->sym_out = req1.sym_out; 4395 req->defobj_out = req1.defobj_out; 4396 } 4397 return (res); 4398 } 4399 if (obj->needed_aux_filtees != NULL) { 4400 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4401 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4402 donelist_init(&donelist); 4403 symlook_init_from_req(&req1, req); 4404 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4405 if (res == 0) { 4406 req->sym_out = req1.sym_out; 4407 req->defobj_out = req1.defobj_out; 4408 return (res); 4409 } 4410 } 4411 } 4412 return (mres); 4413 } 4414 4415 /* Symbol match routine common to both hash functions */ 4416 static bool 4417 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4418 const unsigned long symnum) 4419 { 4420 Elf_Versym verndx; 4421 const Elf_Sym *symp; 4422 const char *strp; 4423 4424 symp = obj->symtab + symnum; 4425 strp = obj->strtab + symp->st_name; 4426 4427 switch (ELF_ST_TYPE(symp->st_info)) { 4428 case STT_FUNC: 4429 case STT_NOTYPE: 4430 case STT_OBJECT: 4431 case STT_COMMON: 4432 case STT_GNU_IFUNC: 4433 if (symp->st_value == 0) 4434 return (false); 4435 /* fallthrough */ 4436 case STT_TLS: 4437 if (symp->st_shndx != SHN_UNDEF) 4438 break; 4439 #ifndef __mips__ 4440 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4441 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4442 break; 4443 #endif 4444 /* fallthrough */ 4445 default: 4446 return (false); 4447 } 4448 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4449 return (false); 4450 4451 if (req->ventry == NULL) { 4452 if (obj->versyms != NULL) { 4453 verndx = VER_NDX(obj->versyms[symnum]); 4454 if (verndx > obj->vernum) { 4455 _rtld_error( 4456 "%s: symbol %s references wrong version %d", 4457 obj->path, obj->strtab + symnum, verndx); 4458 return (false); 4459 } 4460 /* 4461 * If we are not called from dlsym (i.e. this 4462 * is a normal relocation from unversioned 4463 * binary), accept the symbol immediately if 4464 * it happens to have first version after this 4465 * shared object became versioned. Otherwise, 4466 * if symbol is versioned and not hidden, 4467 * remember it. If it is the only symbol with 4468 * this name exported by the shared object, it 4469 * will be returned as a match by the calling 4470 * function. If symbol is global (verndx < 2) 4471 * accept it unconditionally. 4472 */ 4473 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4474 verndx == VER_NDX_GIVEN) { 4475 result->sym_out = symp; 4476 return (true); 4477 } 4478 else if (verndx >= VER_NDX_GIVEN) { 4479 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4480 == 0) { 4481 if (result->vsymp == NULL) 4482 result->vsymp = symp; 4483 result->vcount++; 4484 } 4485 return (false); 4486 } 4487 } 4488 result->sym_out = symp; 4489 return (true); 4490 } 4491 if (obj->versyms == NULL) { 4492 if (object_match_name(obj, req->ventry->name)) { 4493 _rtld_error("%s: object %s should provide version %s " 4494 "for symbol %s", obj_rtld.path, obj->path, 4495 req->ventry->name, obj->strtab + symnum); 4496 return (false); 4497 } 4498 } else { 4499 verndx = VER_NDX(obj->versyms[symnum]); 4500 if (verndx > obj->vernum) { 4501 _rtld_error("%s: symbol %s references wrong version %d", 4502 obj->path, obj->strtab + symnum, verndx); 4503 return (false); 4504 } 4505 if (obj->vertab[verndx].hash != req->ventry->hash || 4506 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4507 /* 4508 * Version does not match. Look if this is a 4509 * global symbol and if it is not hidden. If 4510 * global symbol (verndx < 2) is available, 4511 * use it. Do not return symbol if we are 4512 * called by dlvsym, because dlvsym looks for 4513 * a specific version and default one is not 4514 * what dlvsym wants. 4515 */ 4516 if ((req->flags & SYMLOOK_DLSYM) || 4517 (verndx >= VER_NDX_GIVEN) || 4518 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4519 return (false); 4520 } 4521 } 4522 result->sym_out = symp; 4523 return (true); 4524 } 4525 4526 /* 4527 * Search for symbol using SysV hash function. 4528 * obj->buckets is known not to be NULL at this point; the test for this was 4529 * performed with the obj->valid_hash_sysv assignment. 4530 */ 4531 static int 4532 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4533 { 4534 unsigned long symnum; 4535 Sym_Match_Result matchres; 4536 4537 matchres.sym_out = NULL; 4538 matchres.vsymp = NULL; 4539 matchres.vcount = 0; 4540 4541 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4542 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4543 if (symnum >= obj->nchains) 4544 return (ESRCH); /* Bad object */ 4545 4546 if (matched_symbol(req, obj, &matchres, symnum)) { 4547 req->sym_out = matchres.sym_out; 4548 req->defobj_out = obj; 4549 return (0); 4550 } 4551 } 4552 if (matchres.vcount == 1) { 4553 req->sym_out = matchres.vsymp; 4554 req->defobj_out = obj; 4555 return (0); 4556 } 4557 return (ESRCH); 4558 } 4559 4560 /* Search for symbol using GNU hash function */ 4561 static int 4562 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4563 { 4564 Elf_Addr bloom_word; 4565 const Elf32_Word *hashval; 4566 Elf32_Word bucket; 4567 Sym_Match_Result matchres; 4568 unsigned int h1, h2; 4569 unsigned long symnum; 4570 4571 matchres.sym_out = NULL; 4572 matchres.vsymp = NULL; 4573 matchres.vcount = 0; 4574 4575 /* Pick right bitmask word from Bloom filter array */ 4576 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4577 obj->maskwords_bm_gnu]; 4578 4579 /* Calculate modulus word size of gnu hash and its derivative */ 4580 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4581 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4582 4583 /* Filter out the "definitely not in set" queries */ 4584 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4585 return (ESRCH); 4586 4587 /* Locate hash chain and corresponding value element*/ 4588 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4589 if (bucket == 0) 4590 return (ESRCH); 4591 hashval = &obj->chain_zero_gnu[bucket]; 4592 do { 4593 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4594 symnum = hashval - obj->chain_zero_gnu; 4595 if (matched_symbol(req, obj, &matchres, symnum)) { 4596 req->sym_out = matchres.sym_out; 4597 req->defobj_out = obj; 4598 return (0); 4599 } 4600 } 4601 } while ((*hashval++ & 1) == 0); 4602 if (matchres.vcount == 1) { 4603 req->sym_out = matchres.vsymp; 4604 req->defobj_out = obj; 4605 return (0); 4606 } 4607 return (ESRCH); 4608 } 4609 4610 static void 4611 trace_loaded_objects(Obj_Entry *obj) 4612 { 4613 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4614 int c; 4615 4616 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4617 main_local = ""; 4618 4619 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4620 fmt1 = "\t%o => %p (%x)\n"; 4621 4622 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4623 fmt2 = "\t%o (%x)\n"; 4624 4625 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4626 4627 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4628 Needed_Entry *needed; 4629 const char *name, *path; 4630 bool is_lib; 4631 4632 if (obj->marker) 4633 continue; 4634 if (list_containers && obj->needed != NULL) 4635 rtld_printf("%s:\n", obj->path); 4636 for (needed = obj->needed; needed; needed = needed->next) { 4637 if (needed->obj != NULL) { 4638 if (needed->obj->traced && !list_containers) 4639 continue; 4640 needed->obj->traced = true; 4641 path = needed->obj->path; 4642 } else 4643 path = "not found"; 4644 4645 name = obj->strtab + needed->name; 4646 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4647 4648 fmt = is_lib ? fmt1 : fmt2; 4649 while ((c = *fmt++) != '\0') { 4650 switch (c) { 4651 default: 4652 rtld_putchar(c); 4653 continue; 4654 case '\\': 4655 switch (c = *fmt) { 4656 case '\0': 4657 continue; 4658 case 'n': 4659 rtld_putchar('\n'); 4660 break; 4661 case 't': 4662 rtld_putchar('\t'); 4663 break; 4664 } 4665 break; 4666 case '%': 4667 switch (c = *fmt) { 4668 case '\0': 4669 continue; 4670 case '%': 4671 default: 4672 rtld_putchar(c); 4673 break; 4674 case 'A': 4675 rtld_putstr(main_local); 4676 break; 4677 case 'a': 4678 rtld_putstr(obj_main->path); 4679 break; 4680 case 'o': 4681 rtld_putstr(name); 4682 break; 4683 #if 0 4684 case 'm': 4685 rtld_printf("%d", sodp->sod_major); 4686 break; 4687 case 'n': 4688 rtld_printf("%d", sodp->sod_minor); 4689 break; 4690 #endif 4691 case 'p': 4692 rtld_putstr(path); 4693 break; 4694 case 'x': 4695 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4696 0); 4697 break; 4698 } 4699 break; 4700 } 4701 ++fmt; 4702 } 4703 } 4704 } 4705 } 4706 4707 /* 4708 * Unload a dlopened object and its dependencies from memory and from 4709 * our data structures. It is assumed that the DAG rooted in the 4710 * object has already been unreferenced, and that the object has a 4711 * reference count of 0. 4712 */ 4713 static void 4714 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4715 { 4716 Obj_Entry marker, *obj, *next; 4717 4718 assert(root->refcount == 0); 4719 4720 /* 4721 * Pass over the DAG removing unreferenced objects from 4722 * appropriate lists. 4723 */ 4724 unlink_object(root); 4725 4726 /* Unmap all objects that are no longer referenced. */ 4727 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4728 next = TAILQ_NEXT(obj, next); 4729 if (obj->marker || obj->refcount != 0) 4730 continue; 4731 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4732 obj->mapsize, 0, obj->path); 4733 dbg("unloading \"%s\"", obj->path); 4734 /* 4735 * Unlink the object now to prevent new references from 4736 * being acquired while the bind lock is dropped in 4737 * recursive dlclose() invocations. 4738 */ 4739 TAILQ_REMOVE(&obj_list, obj, next); 4740 obj_count--; 4741 4742 if (obj->filtees_loaded) { 4743 if (next != NULL) { 4744 init_marker(&marker); 4745 TAILQ_INSERT_BEFORE(next, &marker, next); 4746 unload_filtees(obj, lockstate); 4747 next = TAILQ_NEXT(&marker, next); 4748 TAILQ_REMOVE(&obj_list, &marker, next); 4749 } else 4750 unload_filtees(obj, lockstate); 4751 } 4752 release_object(obj); 4753 } 4754 } 4755 4756 static void 4757 unlink_object(Obj_Entry *root) 4758 { 4759 Objlist_Entry *elm; 4760 4761 if (root->refcount == 0) { 4762 /* Remove the object from the RTLD_GLOBAL list. */ 4763 objlist_remove(&list_global, root); 4764 4765 /* Remove the object from all objects' DAG lists. */ 4766 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4767 objlist_remove(&elm->obj->dldags, root); 4768 if (elm->obj != root) 4769 unlink_object(elm->obj); 4770 } 4771 } 4772 } 4773 4774 static void 4775 ref_dag(Obj_Entry *root) 4776 { 4777 Objlist_Entry *elm; 4778 4779 assert(root->dag_inited); 4780 STAILQ_FOREACH(elm, &root->dagmembers, link) 4781 elm->obj->refcount++; 4782 } 4783 4784 static void 4785 unref_dag(Obj_Entry *root) 4786 { 4787 Objlist_Entry *elm; 4788 4789 assert(root->dag_inited); 4790 STAILQ_FOREACH(elm, &root->dagmembers, link) 4791 elm->obj->refcount--; 4792 } 4793 4794 /* 4795 * Common code for MD __tls_get_addr(). 4796 */ 4797 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4798 static void * 4799 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4800 { 4801 Elf_Addr *newdtv, *dtv; 4802 RtldLockState lockstate; 4803 int to_copy; 4804 4805 dtv = *dtvp; 4806 /* Check dtv generation in case new modules have arrived */ 4807 if (dtv[0] != tls_dtv_generation) { 4808 wlock_acquire(rtld_bind_lock, &lockstate); 4809 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4810 to_copy = dtv[1]; 4811 if (to_copy > tls_max_index) 4812 to_copy = tls_max_index; 4813 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4814 newdtv[0] = tls_dtv_generation; 4815 newdtv[1] = tls_max_index; 4816 free(dtv); 4817 lock_release(rtld_bind_lock, &lockstate); 4818 dtv = *dtvp = newdtv; 4819 } 4820 4821 /* Dynamically allocate module TLS if necessary */ 4822 if (dtv[index + 1] == 0) { 4823 /* Signal safe, wlock will block out signals. */ 4824 wlock_acquire(rtld_bind_lock, &lockstate); 4825 if (!dtv[index + 1]) 4826 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4827 lock_release(rtld_bind_lock, &lockstate); 4828 } 4829 return ((void *)(dtv[index + 1] + offset)); 4830 } 4831 4832 void * 4833 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4834 { 4835 Elf_Addr *dtv; 4836 4837 dtv = *dtvp; 4838 /* Check dtv generation in case new modules have arrived */ 4839 if (__predict_true(dtv[0] == tls_dtv_generation && 4840 dtv[index + 1] != 0)) 4841 return ((void *)(dtv[index + 1] + offset)); 4842 return (tls_get_addr_slow(dtvp, index, offset)); 4843 } 4844 4845 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4846 defined(__powerpc__) || defined(__riscv) 4847 4848 /* 4849 * Return pointer to allocated TLS block 4850 */ 4851 static void * 4852 get_tls_block_ptr(void *tcb, size_t tcbsize) 4853 { 4854 size_t extra_size, post_size, pre_size, tls_block_size; 4855 size_t tls_init_align; 4856 4857 tls_init_align = MAX(obj_main->tlsalign, 1); 4858 4859 /* Compute fragments sizes. */ 4860 extra_size = tcbsize - TLS_TCB_SIZE; 4861 post_size = calculate_tls_post_size(tls_init_align); 4862 tls_block_size = tcbsize + post_size; 4863 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4864 4865 return ((char *)tcb - pre_size - extra_size); 4866 } 4867 4868 /* 4869 * Allocate Static TLS using the Variant I method. 4870 * 4871 * For details on the layout, see lib/libc/gen/tls.c. 4872 * 4873 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4874 * it is based on tls_last_offset, and TLS offsets here are really TCB 4875 * offsets, whereas libc's tls_static_space is just the executable's static 4876 * TLS segment. 4877 */ 4878 void * 4879 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4880 { 4881 Obj_Entry *obj; 4882 char *tls_block; 4883 Elf_Addr *dtv, **tcb; 4884 Elf_Addr addr; 4885 Elf_Addr i; 4886 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4887 size_t tls_init_align, tls_init_offset; 4888 4889 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4890 return (oldtcb); 4891 4892 assert(tcbsize >= TLS_TCB_SIZE); 4893 maxalign = MAX(tcbalign, tls_static_max_align); 4894 tls_init_align = MAX(obj_main->tlsalign, 1); 4895 4896 /* Compute fragmets sizes. */ 4897 extra_size = tcbsize - TLS_TCB_SIZE; 4898 post_size = calculate_tls_post_size(tls_init_align); 4899 tls_block_size = tcbsize + post_size; 4900 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4901 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4902 4903 /* Allocate whole TLS block */ 4904 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4905 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4906 4907 if (oldtcb != NULL) { 4908 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4909 tls_static_space); 4910 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4911 4912 /* Adjust the DTV. */ 4913 dtv = tcb[0]; 4914 for (i = 0; i < dtv[1]; i++) { 4915 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4916 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4917 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4918 } 4919 } 4920 } else { 4921 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4922 tcb[0] = dtv; 4923 dtv[0] = tls_dtv_generation; 4924 dtv[1] = tls_max_index; 4925 4926 for (obj = globallist_curr(objs); obj != NULL; 4927 obj = globallist_next(obj)) { 4928 if (obj->tlsoffset == 0) 4929 continue; 4930 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4931 addr = (Elf_Addr)tcb + obj->tlsoffset; 4932 if (tls_init_offset > 0) 4933 memset((void *)addr, 0, tls_init_offset); 4934 if (obj->tlsinitsize > 0) { 4935 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4936 obj->tlsinitsize); 4937 } 4938 if (obj->tlssize > obj->tlsinitsize) { 4939 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4940 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4941 } 4942 dtv[obj->tlsindex + 1] = addr; 4943 } 4944 } 4945 4946 return (tcb); 4947 } 4948 4949 void 4950 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4951 { 4952 Elf_Addr *dtv; 4953 Elf_Addr tlsstart, tlsend; 4954 size_t post_size; 4955 size_t dtvsize, i, tls_init_align; 4956 4957 assert(tcbsize >= TLS_TCB_SIZE); 4958 tls_init_align = MAX(obj_main->tlsalign, 1); 4959 4960 /* Compute fragments sizes. */ 4961 post_size = calculate_tls_post_size(tls_init_align); 4962 4963 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4964 tlsend = (Elf_Addr)tcb + tls_static_space; 4965 4966 dtv = *(Elf_Addr **)tcb; 4967 dtvsize = dtv[1]; 4968 for (i = 0; i < dtvsize; i++) { 4969 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4970 free((void*)dtv[i+2]); 4971 } 4972 } 4973 free(dtv); 4974 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4975 } 4976 4977 #endif 4978 4979 #if defined(__i386__) || defined(__amd64__) 4980 4981 /* 4982 * Allocate Static TLS using the Variant II method. 4983 */ 4984 void * 4985 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4986 { 4987 Obj_Entry *obj; 4988 size_t size, ralign; 4989 char *tls; 4990 Elf_Addr *dtv, *olddtv; 4991 Elf_Addr segbase, oldsegbase, addr; 4992 size_t i; 4993 4994 ralign = tcbalign; 4995 if (tls_static_max_align > ralign) 4996 ralign = tls_static_max_align; 4997 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 4998 4999 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5000 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5001 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5002 5003 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5004 ((Elf_Addr*)segbase)[0] = segbase; 5005 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5006 5007 dtv[0] = tls_dtv_generation; 5008 dtv[1] = tls_max_index; 5009 5010 if (oldtls) { 5011 /* 5012 * Copy the static TLS block over whole. 5013 */ 5014 oldsegbase = (Elf_Addr) oldtls; 5015 memcpy((void *)(segbase - tls_static_space), 5016 (const void *)(oldsegbase - tls_static_space), 5017 tls_static_space); 5018 5019 /* 5020 * If any dynamic TLS blocks have been created tls_get_addr(), 5021 * move them over. 5022 */ 5023 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5024 for (i = 0; i < olddtv[1]; i++) { 5025 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5026 dtv[i+2] = olddtv[i+2]; 5027 olddtv[i+2] = 0; 5028 } 5029 } 5030 5031 /* 5032 * We assume that this block was the one we created with 5033 * allocate_initial_tls(). 5034 */ 5035 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5036 } else { 5037 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5038 if (obj->marker || obj->tlsoffset == 0) 5039 continue; 5040 addr = segbase - obj->tlsoffset; 5041 memset((void*)(addr + obj->tlsinitsize), 5042 0, obj->tlssize - obj->tlsinitsize); 5043 if (obj->tlsinit) { 5044 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5045 obj->static_tls_copied = true; 5046 } 5047 dtv[obj->tlsindex + 1] = addr; 5048 } 5049 } 5050 5051 return (void*) segbase; 5052 } 5053 5054 void 5055 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5056 { 5057 Elf_Addr* dtv; 5058 size_t size, ralign; 5059 int dtvsize, i; 5060 Elf_Addr tlsstart, tlsend; 5061 5062 /* 5063 * Figure out the size of the initial TLS block so that we can 5064 * find stuff which ___tls_get_addr() allocated dynamically. 5065 */ 5066 ralign = tcbalign; 5067 if (tls_static_max_align > ralign) 5068 ralign = tls_static_max_align; 5069 size = roundup(tls_static_space, ralign); 5070 5071 dtv = ((Elf_Addr**)tls)[1]; 5072 dtvsize = dtv[1]; 5073 tlsend = (Elf_Addr) tls; 5074 tlsstart = tlsend - size; 5075 for (i = 0; i < dtvsize; i++) { 5076 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5077 free_aligned((void *)dtv[i + 2]); 5078 } 5079 } 5080 5081 free_aligned((void *)tlsstart); 5082 free((void*) dtv); 5083 } 5084 5085 #endif 5086 5087 /* 5088 * Allocate TLS block for module with given index. 5089 */ 5090 void * 5091 allocate_module_tls(int index) 5092 { 5093 Obj_Entry *obj; 5094 char *p; 5095 5096 TAILQ_FOREACH(obj, &obj_list, next) { 5097 if (obj->marker) 5098 continue; 5099 if (obj->tlsindex == index) 5100 break; 5101 } 5102 if (obj == NULL) { 5103 _rtld_error("Can't find module with TLS index %d", index); 5104 rtld_die(); 5105 } 5106 5107 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5108 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5109 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5110 return (p); 5111 } 5112 5113 bool 5114 allocate_tls_offset(Obj_Entry *obj) 5115 { 5116 size_t off; 5117 5118 if (obj->tls_done) 5119 return true; 5120 5121 if (obj->tlssize == 0) { 5122 obj->tls_done = true; 5123 return true; 5124 } 5125 5126 if (tls_last_offset == 0) 5127 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5128 obj->tlspoffset); 5129 else 5130 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5131 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5132 5133 /* 5134 * If we have already fixed the size of the static TLS block, we 5135 * must stay within that size. When allocating the static TLS, we 5136 * leave a small amount of space spare to be used for dynamically 5137 * loading modules which use static TLS. 5138 */ 5139 if (tls_static_space != 0) { 5140 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5141 return false; 5142 } else if (obj->tlsalign > tls_static_max_align) { 5143 tls_static_max_align = obj->tlsalign; 5144 } 5145 5146 tls_last_offset = obj->tlsoffset = off; 5147 tls_last_size = obj->tlssize; 5148 obj->tls_done = true; 5149 5150 return true; 5151 } 5152 5153 void 5154 free_tls_offset(Obj_Entry *obj) 5155 { 5156 5157 /* 5158 * If we were the last thing to allocate out of the static TLS 5159 * block, we give our space back to the 'allocator'. This is a 5160 * simplistic workaround to allow libGL.so.1 to be loaded and 5161 * unloaded multiple times. 5162 */ 5163 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5164 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5165 tls_last_offset -= obj->tlssize; 5166 tls_last_size = 0; 5167 } 5168 } 5169 5170 void * 5171 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5172 { 5173 void *ret; 5174 RtldLockState lockstate; 5175 5176 wlock_acquire(rtld_bind_lock, &lockstate); 5177 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5178 tcbsize, tcbalign); 5179 lock_release(rtld_bind_lock, &lockstate); 5180 return (ret); 5181 } 5182 5183 void 5184 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5185 { 5186 RtldLockState lockstate; 5187 5188 wlock_acquire(rtld_bind_lock, &lockstate); 5189 free_tls(tcb, tcbsize, tcbalign); 5190 lock_release(rtld_bind_lock, &lockstate); 5191 } 5192 5193 static void 5194 object_add_name(Obj_Entry *obj, const char *name) 5195 { 5196 Name_Entry *entry; 5197 size_t len; 5198 5199 len = strlen(name); 5200 entry = malloc(sizeof(Name_Entry) + len); 5201 5202 if (entry != NULL) { 5203 strcpy(entry->name, name); 5204 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5205 } 5206 } 5207 5208 static int 5209 object_match_name(const Obj_Entry *obj, const char *name) 5210 { 5211 Name_Entry *entry; 5212 5213 STAILQ_FOREACH(entry, &obj->names, link) { 5214 if (strcmp(name, entry->name) == 0) 5215 return (1); 5216 } 5217 return (0); 5218 } 5219 5220 static Obj_Entry * 5221 locate_dependency(const Obj_Entry *obj, const char *name) 5222 { 5223 const Objlist_Entry *entry; 5224 const Needed_Entry *needed; 5225 5226 STAILQ_FOREACH(entry, &list_main, link) { 5227 if (object_match_name(entry->obj, name)) 5228 return entry->obj; 5229 } 5230 5231 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5232 if (strcmp(obj->strtab + needed->name, name) == 0 || 5233 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5234 /* 5235 * If there is DT_NEEDED for the name we are looking for, 5236 * we are all set. Note that object might not be found if 5237 * dependency was not loaded yet, so the function can 5238 * return NULL here. This is expected and handled 5239 * properly by the caller. 5240 */ 5241 return (needed->obj); 5242 } 5243 } 5244 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5245 obj->path, name); 5246 rtld_die(); 5247 } 5248 5249 static int 5250 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5251 const Elf_Vernaux *vna) 5252 { 5253 const Elf_Verdef *vd; 5254 const char *vername; 5255 5256 vername = refobj->strtab + vna->vna_name; 5257 vd = depobj->verdef; 5258 if (vd == NULL) { 5259 _rtld_error("%s: version %s required by %s not defined", 5260 depobj->path, vername, refobj->path); 5261 return (-1); 5262 } 5263 for (;;) { 5264 if (vd->vd_version != VER_DEF_CURRENT) { 5265 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5266 depobj->path, vd->vd_version); 5267 return (-1); 5268 } 5269 if (vna->vna_hash == vd->vd_hash) { 5270 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5271 ((const char *)vd + vd->vd_aux); 5272 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5273 return (0); 5274 } 5275 if (vd->vd_next == 0) 5276 break; 5277 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5278 } 5279 if (vna->vna_flags & VER_FLG_WEAK) 5280 return (0); 5281 _rtld_error("%s: version %s required by %s not found", 5282 depobj->path, vername, refobj->path); 5283 return (-1); 5284 } 5285 5286 static int 5287 rtld_verify_object_versions(Obj_Entry *obj) 5288 { 5289 const Elf_Verneed *vn; 5290 const Elf_Verdef *vd; 5291 const Elf_Verdaux *vda; 5292 const Elf_Vernaux *vna; 5293 const Obj_Entry *depobj; 5294 int maxvernum, vernum; 5295 5296 if (obj->ver_checked) 5297 return (0); 5298 obj->ver_checked = true; 5299 5300 maxvernum = 0; 5301 /* 5302 * Walk over defined and required version records and figure out 5303 * max index used by any of them. Do very basic sanity checking 5304 * while there. 5305 */ 5306 vn = obj->verneed; 5307 while (vn != NULL) { 5308 if (vn->vn_version != VER_NEED_CURRENT) { 5309 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5310 obj->path, vn->vn_version); 5311 return (-1); 5312 } 5313 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5314 for (;;) { 5315 vernum = VER_NEED_IDX(vna->vna_other); 5316 if (vernum > maxvernum) 5317 maxvernum = vernum; 5318 if (vna->vna_next == 0) 5319 break; 5320 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5321 } 5322 if (vn->vn_next == 0) 5323 break; 5324 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5325 } 5326 5327 vd = obj->verdef; 5328 while (vd != NULL) { 5329 if (vd->vd_version != VER_DEF_CURRENT) { 5330 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5331 obj->path, vd->vd_version); 5332 return (-1); 5333 } 5334 vernum = VER_DEF_IDX(vd->vd_ndx); 5335 if (vernum > maxvernum) 5336 maxvernum = vernum; 5337 if (vd->vd_next == 0) 5338 break; 5339 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5340 } 5341 5342 if (maxvernum == 0) 5343 return (0); 5344 5345 /* 5346 * Store version information in array indexable by version index. 5347 * Verify that object version requirements are satisfied along the 5348 * way. 5349 */ 5350 obj->vernum = maxvernum + 1; 5351 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5352 5353 vd = obj->verdef; 5354 while (vd != NULL) { 5355 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5356 vernum = VER_DEF_IDX(vd->vd_ndx); 5357 assert(vernum <= maxvernum); 5358 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5359 obj->vertab[vernum].hash = vd->vd_hash; 5360 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5361 obj->vertab[vernum].file = NULL; 5362 obj->vertab[vernum].flags = 0; 5363 } 5364 if (vd->vd_next == 0) 5365 break; 5366 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5367 } 5368 5369 vn = obj->verneed; 5370 while (vn != NULL) { 5371 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5372 if (depobj == NULL) 5373 return (-1); 5374 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5375 for (;;) { 5376 if (check_object_provided_version(obj, depobj, vna)) 5377 return (-1); 5378 vernum = VER_NEED_IDX(vna->vna_other); 5379 assert(vernum <= maxvernum); 5380 obj->vertab[vernum].hash = vna->vna_hash; 5381 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5382 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5383 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5384 VER_INFO_HIDDEN : 0; 5385 if (vna->vna_next == 0) 5386 break; 5387 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5388 } 5389 if (vn->vn_next == 0) 5390 break; 5391 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5392 } 5393 return 0; 5394 } 5395 5396 static int 5397 rtld_verify_versions(const Objlist *objlist) 5398 { 5399 Objlist_Entry *entry; 5400 int rc; 5401 5402 rc = 0; 5403 STAILQ_FOREACH(entry, objlist, link) { 5404 /* 5405 * Skip dummy objects or objects that have their version requirements 5406 * already checked. 5407 */ 5408 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5409 continue; 5410 if (rtld_verify_object_versions(entry->obj) == -1) { 5411 rc = -1; 5412 if (ld_tracing == NULL) 5413 break; 5414 } 5415 } 5416 if (rc == 0 || ld_tracing != NULL) 5417 rc = rtld_verify_object_versions(&obj_rtld); 5418 return rc; 5419 } 5420 5421 const Ver_Entry * 5422 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5423 { 5424 Elf_Versym vernum; 5425 5426 if (obj->vertab) { 5427 vernum = VER_NDX(obj->versyms[symnum]); 5428 if (vernum >= obj->vernum) { 5429 _rtld_error("%s: symbol %s has wrong verneed value %d", 5430 obj->path, obj->strtab + symnum, vernum); 5431 } else if (obj->vertab[vernum].hash != 0) { 5432 return &obj->vertab[vernum]; 5433 } 5434 } 5435 return NULL; 5436 } 5437 5438 int 5439 _rtld_get_stack_prot(void) 5440 { 5441 5442 return (stack_prot); 5443 } 5444 5445 int 5446 _rtld_is_dlopened(void *arg) 5447 { 5448 Obj_Entry *obj; 5449 RtldLockState lockstate; 5450 int res; 5451 5452 rlock_acquire(rtld_bind_lock, &lockstate); 5453 obj = dlcheck(arg); 5454 if (obj == NULL) 5455 obj = obj_from_addr(arg); 5456 if (obj == NULL) { 5457 _rtld_error("No shared object contains address"); 5458 lock_release(rtld_bind_lock, &lockstate); 5459 return (-1); 5460 } 5461 res = obj->dlopened ? 1 : 0; 5462 lock_release(rtld_bind_lock, &lockstate); 5463 return (res); 5464 } 5465 5466 static int 5467 obj_remap_relro(Obj_Entry *obj, int prot) 5468 { 5469 5470 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5471 prot) == -1) { 5472 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5473 obj->path, prot, rtld_strerror(errno)); 5474 return (-1); 5475 } 5476 return (0); 5477 } 5478 5479 static int 5480 obj_disable_relro(Obj_Entry *obj) 5481 { 5482 5483 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5484 } 5485 5486 static int 5487 obj_enforce_relro(Obj_Entry *obj) 5488 { 5489 5490 return (obj_remap_relro(obj, PROT_READ)); 5491 } 5492 5493 static void 5494 map_stacks_exec(RtldLockState *lockstate) 5495 { 5496 void (*thr_map_stacks_exec)(void); 5497 5498 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5499 return; 5500 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5501 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5502 if (thr_map_stacks_exec != NULL) { 5503 stack_prot |= PROT_EXEC; 5504 thr_map_stacks_exec(); 5505 } 5506 } 5507 5508 static void 5509 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5510 { 5511 Objlist_Entry *elm; 5512 Obj_Entry *obj; 5513 void (*distrib)(size_t, void *, size_t, size_t); 5514 5515 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5516 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5517 if (distrib == NULL) 5518 return; 5519 STAILQ_FOREACH(elm, list, link) { 5520 obj = elm->obj; 5521 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5522 continue; 5523 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5524 obj->tlssize); 5525 obj->static_tls_copied = true; 5526 } 5527 } 5528 5529 void 5530 symlook_init(SymLook *dst, const char *name) 5531 { 5532 5533 bzero(dst, sizeof(*dst)); 5534 dst->name = name; 5535 dst->hash = elf_hash(name); 5536 dst->hash_gnu = gnu_hash(name); 5537 } 5538 5539 static void 5540 symlook_init_from_req(SymLook *dst, const SymLook *src) 5541 { 5542 5543 dst->name = src->name; 5544 dst->hash = src->hash; 5545 dst->hash_gnu = src->hash_gnu; 5546 dst->ventry = src->ventry; 5547 dst->flags = src->flags; 5548 dst->defobj_out = NULL; 5549 dst->sym_out = NULL; 5550 dst->lockstate = src->lockstate; 5551 } 5552 5553 static int 5554 open_binary_fd(const char *argv0, bool search_in_path, 5555 const char **binpath_res) 5556 { 5557 char *binpath, *pathenv, *pe, *res1; 5558 const char *res; 5559 int fd; 5560 5561 binpath = NULL; 5562 res = NULL; 5563 if (search_in_path && strchr(argv0, '/') == NULL) { 5564 binpath = xmalloc(PATH_MAX); 5565 pathenv = getenv("PATH"); 5566 if (pathenv == NULL) { 5567 _rtld_error("-p and no PATH environment variable"); 5568 rtld_die(); 5569 } 5570 pathenv = strdup(pathenv); 5571 if (pathenv == NULL) { 5572 _rtld_error("Cannot allocate memory"); 5573 rtld_die(); 5574 } 5575 fd = -1; 5576 errno = ENOENT; 5577 while ((pe = strsep(&pathenv, ":")) != NULL) { 5578 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5579 continue; 5580 if (binpath[0] != '\0' && 5581 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5582 continue; 5583 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5584 continue; 5585 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5586 if (fd != -1 || errno != ENOENT) { 5587 res = binpath; 5588 break; 5589 } 5590 } 5591 free(pathenv); 5592 } else { 5593 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5594 res = argv0; 5595 } 5596 5597 if (fd == -1) { 5598 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5599 rtld_die(); 5600 } 5601 if (res != NULL && res[0] != '/') { 5602 res1 = xmalloc(PATH_MAX); 5603 if (realpath(res, res1) != NULL) { 5604 if (res != argv0) 5605 free(__DECONST(char *, res)); 5606 res = res1; 5607 } else { 5608 free(res1); 5609 } 5610 } 5611 *binpath_res = res; 5612 return (fd); 5613 } 5614 5615 /* 5616 * Parse a set of command-line arguments. 5617 */ 5618 static int 5619 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5620 const char **argv0) 5621 { 5622 const char *arg; 5623 char machine[64]; 5624 size_t sz; 5625 int arglen, fd, i, j, mib[2]; 5626 char opt; 5627 bool seen_b, seen_f; 5628 5629 dbg("Parsing command-line arguments"); 5630 *use_pathp = false; 5631 *fdp = -1; 5632 seen_b = seen_f = false; 5633 5634 for (i = 1; i < argc; i++ ) { 5635 arg = argv[i]; 5636 dbg("argv[%d]: '%s'", i, arg); 5637 5638 /* 5639 * rtld arguments end with an explicit "--" or with the first 5640 * non-prefixed argument. 5641 */ 5642 if (strcmp(arg, "--") == 0) { 5643 i++; 5644 break; 5645 } 5646 if (arg[0] != '-') 5647 break; 5648 5649 /* 5650 * All other arguments are single-character options that can 5651 * be combined, so we need to search through `arg` for them. 5652 */ 5653 arglen = strlen(arg); 5654 for (j = 1; j < arglen; j++) { 5655 opt = arg[j]; 5656 if (opt == 'h') { 5657 print_usage(argv[0]); 5658 _exit(0); 5659 } else if (opt == 'b') { 5660 if (seen_f) { 5661 _rtld_error("Both -b and -f specified"); 5662 rtld_die(); 5663 } 5664 i++; 5665 *argv0 = argv[i]; 5666 seen_b = true; 5667 break; 5668 } else if (opt == 'f') { 5669 if (seen_b) { 5670 _rtld_error("Both -b and -f specified"); 5671 rtld_die(); 5672 } 5673 5674 /* 5675 * -f XX can be used to specify a 5676 * descriptor for the binary named at 5677 * the command line (i.e., the later 5678 * argument will specify the process 5679 * name but the descriptor is what 5680 * will actually be executed). 5681 * 5682 * -f must be the last option in, e.g., -abcf. 5683 */ 5684 if (j != arglen - 1) { 5685 _rtld_error("Invalid options: %s", arg); 5686 rtld_die(); 5687 } 5688 i++; 5689 fd = parse_integer(argv[i]); 5690 if (fd == -1) { 5691 _rtld_error( 5692 "Invalid file descriptor: '%s'", 5693 argv[i]); 5694 rtld_die(); 5695 } 5696 *fdp = fd; 5697 seen_f = true; 5698 break; 5699 } else if (opt == 'p') { 5700 *use_pathp = true; 5701 } else if (opt == 'v') { 5702 machine[0] = '\0'; 5703 mib[0] = CTL_HW; 5704 mib[1] = HW_MACHINE; 5705 sz = sizeof(machine); 5706 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5707 rtld_printf( 5708 "FreeBSD ld-elf.so.1 %s\n" 5709 "FreeBSD_version %d\n" 5710 "Default lib path %s\n" 5711 "Env prefix %s\n" 5712 "Hint file %s\n" 5713 "libmap file %s\n", 5714 machine, 5715 __FreeBSD_version, ld_standard_library_path, 5716 ld_env_prefix, ld_elf_hints_default, 5717 ld_path_libmap_conf); 5718 _exit(0); 5719 } else { 5720 _rtld_error("Invalid argument: '%s'", arg); 5721 print_usage(argv[0]); 5722 rtld_die(); 5723 } 5724 } 5725 } 5726 5727 if (!seen_b) 5728 *argv0 = argv[i]; 5729 return (i); 5730 } 5731 5732 /* 5733 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5734 */ 5735 static int 5736 parse_integer(const char *str) 5737 { 5738 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5739 const char *orig; 5740 int n; 5741 char c; 5742 5743 orig = str; 5744 n = 0; 5745 for (c = *str; c != '\0'; c = *++str) { 5746 if (c < '0' || c > '9') 5747 return (-1); 5748 5749 n *= RADIX; 5750 n += c - '0'; 5751 } 5752 5753 /* Make sure we actually parsed something. */ 5754 if (str == orig) 5755 return (-1); 5756 return (n); 5757 } 5758 5759 static void 5760 print_usage(const char *argv0) 5761 { 5762 5763 rtld_printf( 5764 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5765 "\n" 5766 "Options:\n" 5767 " -h Display this help message\n" 5768 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5769 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5770 " -p Search in PATH for named binary\n" 5771 " -v Display identification information\n" 5772 " -- End of RTLD options\n" 5773 " <binary> Name of process to execute\n" 5774 " <args> Arguments to the executed process\n", argv0); 5775 } 5776 5777 /* 5778 * Overrides for libc_pic-provided functions. 5779 */ 5780 5781 int 5782 __getosreldate(void) 5783 { 5784 size_t len; 5785 int oid[2]; 5786 int error, osrel; 5787 5788 if (osreldate != 0) 5789 return (osreldate); 5790 5791 oid[0] = CTL_KERN; 5792 oid[1] = KERN_OSRELDATE; 5793 osrel = 0; 5794 len = sizeof(osrel); 5795 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5796 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5797 osreldate = osrel; 5798 return (osreldate); 5799 } 5800 const char * 5801 rtld_strerror(int errnum) 5802 { 5803 5804 if (errnum < 0 || errnum >= sys_nerr) 5805 return ("Unknown error"); 5806 return (sys_errlist[errnum]); 5807 } 5808 5809 /* malloc */ 5810 void * 5811 malloc(size_t nbytes) 5812 { 5813 5814 return (__crt_malloc(nbytes)); 5815 } 5816 5817 void * 5818 calloc(size_t num, size_t size) 5819 { 5820 5821 return (__crt_calloc(num, size)); 5822 } 5823 5824 void 5825 free(void *cp) 5826 { 5827 5828 __crt_free(cp); 5829 } 5830 5831 void * 5832 realloc(void *cp, size_t nbytes) 5833 { 5834 5835 return (__crt_realloc(cp, nbytes)); 5836 } 5837 5838 extern int _rtld_version__FreeBSD_version __exported; 5839 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5840 5841 extern char _rtld_version_laddr_offset __exported; 5842 char _rtld_version_laddr_offset; 5843