1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path, 138 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 140 static int parse_integer(const char *); 141 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 142 static void print_usage(const char *argv0); 143 static void release_object(Obj_Entry *); 144 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 145 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 146 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 147 int flags, RtldLockState *lockstate); 148 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 149 RtldLockState *); 150 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 151 static int rtld_dirname(const char *, char *); 152 static int rtld_dirname_abs(const char *, char *); 153 static void *rtld_dlopen(const char *name, int fd, int mode); 154 static void rtld_exit(void); 155 static void rtld_nop_exit(void); 156 static char *search_library_path(const char *, const char *, const char *, 157 int *); 158 static char *search_library_pathfds(const char *, const char *, int *); 159 static const void **get_program_var_addr(const char *, RtldLockState *); 160 static void set_program_var(const char *, const void *); 161 static int symlook_default(SymLook *, const Obj_Entry *refobj); 162 static int symlook_global(SymLook *, DoneList *); 163 static void symlook_init_from_req(SymLook *, const SymLook *); 164 static int symlook_list(SymLook *, const Objlist *, DoneList *); 165 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 166 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 167 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 168 static void trace_loaded_objects(Obj_Entry *); 169 static void unlink_object(Obj_Entry *); 170 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 171 static void unref_dag(Obj_Entry *); 172 static void ref_dag(Obj_Entry *); 173 static char *origin_subst_one(Obj_Entry *, char *, const char *, 174 const char *, bool); 175 static char *origin_subst(Obj_Entry *, const char *); 176 static bool obj_resolve_origin(Obj_Entry *obj); 177 static void preinit_main(void); 178 static int rtld_verify_versions(const Objlist *); 179 static int rtld_verify_object_versions(Obj_Entry *); 180 static void object_add_name(Obj_Entry *, const char *); 181 static int object_match_name(const Obj_Entry *, const char *); 182 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 183 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 184 struct dl_phdr_info *phdr_info); 185 static uint32_t gnu_hash(const char *); 186 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 187 const unsigned long); 188 189 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 190 void _r_debug_postinit(struct link_map *) __noinline __exported; 191 192 int __sys_openat(int, const char *, int, ...); 193 194 /* 195 * Data declarations. 196 */ 197 static char *error_message; /* Message for dlerror(), or NULL */ 198 struct r_debug r_debug __exported; /* for GDB; */ 199 static bool libmap_disable; /* Disable libmap */ 200 static bool ld_loadfltr; /* Immediate filters processing */ 201 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 202 static bool trust; /* False for setuid and setgid programs */ 203 static bool dangerous_ld_env; /* True if environment variables have been 204 used to affect the libraries loaded */ 205 bool ld_bind_not; /* Disable PLT update */ 206 static char *ld_bind_now; /* Environment variable for immediate binding */ 207 static char *ld_debug; /* Environment variable for debugging */ 208 static char *ld_library_path; /* Environment variable for search path */ 209 static char *ld_library_dirs; /* Environment variable for library descriptors */ 210 static char *ld_preload; /* Environment variable for libraries to 211 load first */ 212 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 213 static const char *ld_tracing; /* Called from ldd to print libs */ 214 static char *ld_utrace; /* Use utrace() to log events. */ 215 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 216 static Obj_Entry *obj_main; /* The main program shared object */ 217 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 218 static unsigned int obj_count; /* Number of objects in obj_list */ 219 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 220 221 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 222 STAILQ_HEAD_INITIALIZER(list_global); 223 static Objlist list_main = /* Objects loaded at program startup */ 224 STAILQ_HEAD_INITIALIZER(list_main); 225 static Objlist list_fini = /* Objects needing fini() calls */ 226 STAILQ_HEAD_INITIALIZER(list_fini); 227 228 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 229 230 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 231 232 extern Elf_Dyn _DYNAMIC; 233 #pragma weak _DYNAMIC 234 235 int dlclose(void *) __exported; 236 char *dlerror(void) __exported; 237 void *dlopen(const char *, int) __exported; 238 void *fdlopen(int, int) __exported; 239 void *dlsym(void *, const char *) __exported; 240 dlfunc_t dlfunc(void *, const char *) __exported; 241 void *dlvsym(void *, const char *, const char *) __exported; 242 int dladdr(const void *, Dl_info *) __exported; 243 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 244 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 245 int dlinfo(void *, int , void *) __exported; 246 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 247 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 248 int _rtld_get_stack_prot(void) __exported; 249 int _rtld_is_dlopened(void *) __exported; 250 void _rtld_error(const char *, ...) __exported; 251 252 /* Only here to fix -Wmissing-prototypes warnings */ 253 int __getosreldate(void); 254 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 255 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 256 257 258 int npagesizes; 259 static int osreldate; 260 size_t *pagesizes; 261 262 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 263 static int max_stack_flags; 264 265 /* 266 * Global declarations normally provided by crt1. The dynamic linker is 267 * not built with crt1, so we have to provide them ourselves. 268 */ 269 char *__progname; 270 char **environ; 271 272 /* 273 * Used to pass argc, argv to init functions. 274 */ 275 int main_argc; 276 char **main_argv; 277 278 /* 279 * Globals to control TLS allocation. 280 */ 281 size_t tls_last_offset; /* Static TLS offset of last module */ 282 size_t tls_last_size; /* Static TLS size of last module */ 283 size_t tls_static_space; /* Static TLS space allocated */ 284 static size_t tls_static_max_align; 285 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 286 int tls_max_index = 1; /* Largest module index allocated */ 287 288 static bool ld_library_path_rpath = false; 289 bool ld_fast_sigblock = false; 290 291 /* 292 * Globals for path names, and such 293 */ 294 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 295 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 296 const char *ld_path_rtld = _PATH_RTLD; 297 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 298 const char *ld_env_prefix = LD_; 299 300 static void (*rtld_exit_ptr)(void); 301 302 /* 303 * Fill in a DoneList with an allocation large enough to hold all of 304 * the currently-loaded objects. Keep this as a macro since it calls 305 * alloca and we want that to occur within the scope of the caller. 306 */ 307 #define donelist_init(dlp) \ 308 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 309 assert((dlp)->objs != NULL), \ 310 (dlp)->num_alloc = obj_count, \ 311 (dlp)->num_used = 0) 312 313 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 314 if (ld_utrace != NULL) \ 315 ld_utrace_log(e, h, mb, ms, r, n); \ 316 } while (0) 317 318 static void 319 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 320 int refcnt, const char *name) 321 { 322 struct utrace_rtld ut; 323 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 324 325 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 326 ut.event = event; 327 ut.handle = handle; 328 ut.mapbase = mapbase; 329 ut.mapsize = mapsize; 330 ut.refcnt = refcnt; 331 bzero(ut.name, sizeof(ut.name)); 332 if (name) 333 strlcpy(ut.name, name, sizeof(ut.name)); 334 utrace(&ut, sizeof(ut)); 335 } 336 337 #ifdef RTLD_VARIANT_ENV_NAMES 338 /* 339 * construct the env variable based on the type of binary that's 340 * running. 341 */ 342 static inline const char * 343 _LD(const char *var) 344 { 345 static char buffer[128]; 346 347 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 348 strlcat(buffer, var, sizeof(buffer)); 349 return (buffer); 350 } 351 #else 352 #define _LD(x) LD_ x 353 #endif 354 355 /* 356 * Main entry point for dynamic linking. The first argument is the 357 * stack pointer. The stack is expected to be laid out as described 358 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 359 * Specifically, the stack pointer points to a word containing 360 * ARGC. Following that in the stack is a null-terminated sequence 361 * of pointers to argument strings. Then comes a null-terminated 362 * sequence of pointers to environment strings. Finally, there is a 363 * sequence of "auxiliary vector" entries. 364 * 365 * The second argument points to a place to store the dynamic linker's 366 * exit procedure pointer and the third to a place to store the main 367 * program's object. 368 * 369 * The return value is the main program's entry point. 370 */ 371 func_ptr_type 372 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 373 { 374 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 375 Objlist_Entry *entry; 376 Obj_Entry *last_interposer, *obj, *preload_tail; 377 const Elf_Phdr *phdr; 378 Objlist initlist; 379 RtldLockState lockstate; 380 struct stat st; 381 Elf_Addr *argcp; 382 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 383 const char *argv0, *binpath; 384 caddr_t imgentry; 385 char buf[MAXPATHLEN]; 386 int argc, fd, i, phnum, rtld_argc; 387 #ifdef __powerpc__ 388 int old_auxv_format = 1; 389 #endif 390 bool dir_enable, explicit_fd, search_in_path; 391 392 /* 393 * On entry, the dynamic linker itself has not been relocated yet. 394 * Be very careful not to reference any global data until after 395 * init_rtld has returned. It is OK to reference file-scope statics 396 * and string constants, and to call static and global functions. 397 */ 398 399 /* Find the auxiliary vector on the stack. */ 400 argcp = sp; 401 argc = *sp++; 402 argv = (char **) sp; 403 sp += argc + 1; /* Skip over arguments and NULL terminator */ 404 env = (char **) sp; 405 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 406 ; 407 aux = (Elf_Auxinfo *) sp; 408 409 /* Digest the auxiliary vector. */ 410 for (i = 0; i < AT_COUNT; i++) 411 aux_info[i] = NULL; 412 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 413 if (auxp->a_type < AT_COUNT) 414 aux_info[auxp->a_type] = auxp; 415 #ifdef __powerpc__ 416 if (auxp->a_type == 23) /* AT_STACKPROT */ 417 old_auxv_format = 0; 418 #endif 419 } 420 421 #ifdef __powerpc__ 422 if (old_auxv_format) { 423 /* Remap from old-style auxv numbers. */ 424 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 425 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 426 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 427 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 428 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 429 aux_info[13] = NULL; /* AT_GID */ 430 431 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 432 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 433 aux_info[16] = aux_info[14]; /* AT_CANARY */ 434 aux_info[14] = NULL; /* AT_EGID */ 435 } 436 #endif 437 438 /* Initialize and relocate ourselves. */ 439 assert(aux_info[AT_BASE] != NULL); 440 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 441 442 __progname = obj_rtld.path; 443 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 444 environ = env; 445 main_argc = argc; 446 main_argv = argv; 447 448 if (aux_info[AT_BSDFLAGS] != NULL && 449 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 450 ld_fast_sigblock = true; 451 452 trust = !issetugid(); 453 454 md_abi_variant_hook(aux_info); 455 456 fd = -1; 457 if (aux_info[AT_EXECFD] != NULL) { 458 fd = aux_info[AT_EXECFD]->a_un.a_val; 459 } else { 460 assert(aux_info[AT_PHDR] != NULL); 461 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 462 if (phdr == obj_rtld.phdr) { 463 if (!trust) { 464 _rtld_error("Tainted process refusing to run binary %s", 465 argv0); 466 rtld_die(); 467 } 468 dbg("opening main program in direct exec mode"); 469 if (argc >= 2) { 470 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 471 argv0 = argv[rtld_argc]; 472 explicit_fd = (fd != -1); 473 binpath = NULL; 474 if (!explicit_fd) 475 fd = open_binary_fd(argv0, search_in_path, &binpath); 476 if (fstat(fd, &st) == -1) { 477 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 478 explicit_fd ? "user-provided descriptor" : argv0, 479 rtld_strerror(errno)); 480 rtld_die(); 481 } 482 483 /* 484 * Rough emulation of the permission checks done by 485 * execve(2), only Unix DACs are checked, ACLs are 486 * ignored. Preserve the semantic of disabling owner 487 * to execute if owner x bit is cleared, even if 488 * others x bit is enabled. 489 * mmap(2) does not allow to mmap with PROT_EXEC if 490 * binary' file comes from noexec mount. We cannot 491 * set a text reference on the binary. 492 */ 493 dir_enable = false; 494 if (st.st_uid == geteuid()) { 495 if ((st.st_mode & S_IXUSR) != 0) 496 dir_enable = true; 497 } else if (st.st_gid == getegid()) { 498 if ((st.st_mode & S_IXGRP) != 0) 499 dir_enable = true; 500 } else if ((st.st_mode & S_IXOTH) != 0) { 501 dir_enable = true; 502 } 503 if (!dir_enable) { 504 _rtld_error("No execute permission for binary %s", 505 argv0); 506 rtld_die(); 507 } 508 509 /* 510 * For direct exec mode, argv[0] is the interpreter 511 * name, we must remove it and shift arguments left 512 * before invoking binary main. Since stack layout 513 * places environment pointers and aux vectors right 514 * after the terminating NULL, we must shift 515 * environment and aux as well. 516 */ 517 main_argc = argc - rtld_argc; 518 for (i = 0; i <= main_argc; i++) 519 argv[i] = argv[i + rtld_argc]; 520 *argcp -= rtld_argc; 521 environ = env = envp = argv + main_argc + 1; 522 dbg("move env from %p to %p", envp + rtld_argc, envp); 523 do { 524 *envp = *(envp + rtld_argc); 525 } while (*envp++ != NULL); 526 aux = auxp = (Elf_Auxinfo *)envp; 527 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 528 dbg("move aux from %p to %p", auxpf, aux); 529 /* XXXKIB insert place for AT_EXECPATH if not present */ 530 for (;; auxp++, auxpf++) { 531 *auxp = *auxpf; 532 if (auxp->a_type == AT_NULL) 533 break; 534 } 535 /* Since the auxiliary vector has moved, redigest it. */ 536 for (i = 0; i < AT_COUNT; i++) 537 aux_info[i] = NULL; 538 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 539 if (auxp->a_type < AT_COUNT) 540 aux_info[auxp->a_type] = auxp; 541 } 542 543 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 544 if (binpath == NULL) { 545 aux_info[AT_EXECPATH] = NULL; 546 } else { 547 if (aux_info[AT_EXECPATH] == NULL) { 548 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 549 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 550 } 551 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 552 binpath); 553 } 554 } else { 555 _rtld_error("No binary"); 556 rtld_die(); 557 } 558 } 559 } 560 561 ld_bind_now = getenv(_LD("BIND_NOW")); 562 563 /* 564 * If the process is tainted, then we un-set the dangerous environment 565 * variables. The process will be marked as tainted until setuid(2) 566 * is called. If any child process calls setuid(2) we do not want any 567 * future processes to honor the potentially un-safe variables. 568 */ 569 if (!trust) { 570 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 571 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 572 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 573 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 574 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 575 _rtld_error("environment corrupt; aborting"); 576 rtld_die(); 577 } 578 } 579 ld_debug = getenv(_LD("DEBUG")); 580 if (ld_bind_now == NULL) 581 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 582 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 583 libmap_override = getenv(_LD("LIBMAP")); 584 ld_library_path = getenv(_LD("LIBRARY_PATH")); 585 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 586 ld_preload = getenv(_LD("PRELOAD")); 587 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 588 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 589 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 590 if (library_path_rpath != NULL) { 591 if (library_path_rpath[0] == 'y' || 592 library_path_rpath[0] == 'Y' || 593 library_path_rpath[0] == '1') 594 ld_library_path_rpath = true; 595 else 596 ld_library_path_rpath = false; 597 } 598 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 599 (ld_library_path != NULL) || (ld_preload != NULL) || 600 (ld_elf_hints_path != NULL) || ld_loadfltr; 601 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 602 ld_utrace = getenv(_LD("UTRACE")); 603 604 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 605 ld_elf_hints_path = ld_elf_hints_default; 606 607 if (ld_debug != NULL && *ld_debug != '\0') 608 debug = 1; 609 dbg("%s is initialized, base address = %p", __progname, 610 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 611 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 612 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 613 614 dbg("initializing thread locks"); 615 lockdflt_init(); 616 617 /* 618 * Load the main program, or process its program header if it is 619 * already loaded. 620 */ 621 if (fd != -1) { /* Load the main program. */ 622 dbg("loading main program"); 623 obj_main = map_object(fd, argv0, NULL); 624 close(fd); 625 if (obj_main == NULL) 626 rtld_die(); 627 max_stack_flags = obj_main->stack_flags; 628 } else { /* Main program already loaded. */ 629 dbg("processing main program's program header"); 630 assert(aux_info[AT_PHDR] != NULL); 631 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 632 assert(aux_info[AT_PHNUM] != NULL); 633 phnum = aux_info[AT_PHNUM]->a_un.a_val; 634 assert(aux_info[AT_PHENT] != NULL); 635 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 636 assert(aux_info[AT_ENTRY] != NULL); 637 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 638 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 639 rtld_die(); 640 } 641 642 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 643 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 644 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 645 if (kexecpath[0] == '/') 646 obj_main->path = kexecpath; 647 else if (getcwd(buf, sizeof(buf)) == NULL || 648 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 649 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 650 obj_main->path = xstrdup(argv0); 651 else 652 obj_main->path = xstrdup(buf); 653 } else { 654 dbg("No AT_EXECPATH or direct exec"); 655 obj_main->path = xstrdup(argv0); 656 } 657 dbg("obj_main path %s", obj_main->path); 658 obj_main->mainprog = true; 659 660 if (aux_info[AT_STACKPROT] != NULL && 661 aux_info[AT_STACKPROT]->a_un.a_val != 0) 662 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 663 664 #ifndef COMPAT_32BIT 665 /* 666 * Get the actual dynamic linker pathname from the executable if 667 * possible. (It should always be possible.) That ensures that 668 * gdb will find the right dynamic linker even if a non-standard 669 * one is being used. 670 */ 671 if (obj_main->interp != NULL && 672 strcmp(obj_main->interp, obj_rtld.path) != 0) { 673 free(obj_rtld.path); 674 obj_rtld.path = xstrdup(obj_main->interp); 675 __progname = obj_rtld.path; 676 } 677 #endif 678 679 if (!digest_dynamic(obj_main, 0)) 680 rtld_die(); 681 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 682 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 683 obj_main->dynsymcount); 684 685 linkmap_add(obj_main); 686 linkmap_add(&obj_rtld); 687 688 /* Link the main program into the list of objects. */ 689 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 690 obj_count++; 691 obj_loads++; 692 693 /* Initialize a fake symbol for resolving undefined weak references. */ 694 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 695 sym_zero.st_shndx = SHN_UNDEF; 696 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 697 698 if (!libmap_disable) 699 libmap_disable = (bool)lm_init(libmap_override); 700 701 dbg("loading LD_PRELOAD libraries"); 702 if (load_preload_objects() == -1) 703 rtld_die(); 704 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 705 706 dbg("loading needed objects"); 707 if (load_needed_objects(obj_main, 0) == -1) 708 rtld_die(); 709 710 /* Make a list of all objects loaded at startup. */ 711 last_interposer = obj_main; 712 TAILQ_FOREACH(obj, &obj_list, next) { 713 if (obj->marker) 714 continue; 715 if (obj->z_interpose && obj != obj_main) { 716 objlist_put_after(&list_main, last_interposer, obj); 717 last_interposer = obj; 718 } else { 719 objlist_push_tail(&list_main, obj); 720 } 721 obj->refcount++; 722 } 723 724 dbg("checking for required versions"); 725 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 726 rtld_die(); 727 728 if (ld_tracing) { /* We're done */ 729 trace_loaded_objects(obj_main); 730 exit(0); 731 } 732 733 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 734 dump_relocations(obj_main); 735 exit (0); 736 } 737 738 /* 739 * Processing tls relocations requires having the tls offsets 740 * initialized. Prepare offsets before starting initial 741 * relocation processing. 742 */ 743 dbg("initializing initial thread local storage offsets"); 744 STAILQ_FOREACH(entry, &list_main, link) { 745 /* 746 * Allocate all the initial objects out of the static TLS 747 * block even if they didn't ask for it. 748 */ 749 allocate_tls_offset(entry->obj); 750 } 751 752 if (relocate_objects(obj_main, 753 ld_bind_now != NULL && *ld_bind_now != '\0', 754 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 755 rtld_die(); 756 757 dbg("doing copy relocations"); 758 if (do_copy_relocations(obj_main) == -1) 759 rtld_die(); 760 761 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 762 dump_relocations(obj_main); 763 exit (0); 764 } 765 766 ifunc_init(aux); 767 768 /* 769 * Setup TLS for main thread. This must be done after the 770 * relocations are processed, since tls initialization section 771 * might be the subject for relocations. 772 */ 773 dbg("initializing initial thread local storage"); 774 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 775 776 dbg("initializing key program variables"); 777 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 778 set_program_var("environ", env); 779 set_program_var("__elf_aux_vector", aux); 780 781 /* Make a list of init functions to call. */ 782 objlist_init(&initlist); 783 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 784 preload_tail, &initlist); 785 786 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 787 788 map_stacks_exec(NULL); 789 790 if (!obj_main->crt_no_init) { 791 /* 792 * Make sure we don't call the main program's init and fini 793 * functions for binaries linked with old crt1 which calls 794 * _init itself. 795 */ 796 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 797 obj_main->preinit_array = obj_main->init_array = 798 obj_main->fini_array = (Elf_Addr)NULL; 799 } 800 801 /* 802 * Execute MD initializers required before we call the objects' 803 * init functions. 804 */ 805 pre_init(); 806 807 wlock_acquire(rtld_bind_lock, &lockstate); 808 809 dbg("resolving ifuncs"); 810 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 811 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 812 rtld_die(); 813 814 rtld_exit_ptr = rtld_exit; 815 if (obj_main->crt_no_init) 816 preinit_main(); 817 objlist_call_init(&initlist, &lockstate); 818 _r_debug_postinit(&obj_main->linkmap); 819 objlist_clear(&initlist); 820 dbg("loading filtees"); 821 TAILQ_FOREACH(obj, &obj_list, next) { 822 if (obj->marker) 823 continue; 824 if (ld_loadfltr || obj->z_loadfltr) 825 load_filtees(obj, 0, &lockstate); 826 } 827 828 dbg("enforcing main obj relro"); 829 if (obj_enforce_relro(obj_main) == -1) 830 rtld_die(); 831 832 lock_release(rtld_bind_lock, &lockstate); 833 834 dbg("transferring control to program entry point = %p", obj_main->entry); 835 836 /* Return the exit procedure and the program entry point. */ 837 *exit_proc = rtld_exit_ptr; 838 *objp = obj_main; 839 return (func_ptr_type) obj_main->entry; 840 } 841 842 void * 843 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 844 { 845 void *ptr; 846 Elf_Addr target; 847 848 ptr = (void *)make_function_pointer(def, obj); 849 target = call_ifunc_resolver(ptr); 850 return ((void *)target); 851 } 852 853 /* 854 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 855 * Changes to this function should be applied there as well. 856 */ 857 Elf_Addr 858 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 859 { 860 const Elf_Rel *rel; 861 const Elf_Sym *def; 862 const Obj_Entry *defobj; 863 Elf_Addr *where; 864 Elf_Addr target; 865 RtldLockState lockstate; 866 867 rlock_acquire(rtld_bind_lock, &lockstate); 868 if (sigsetjmp(lockstate.env, 0) != 0) 869 lock_upgrade(rtld_bind_lock, &lockstate); 870 if (obj->pltrel) 871 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 872 else 873 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 874 875 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 876 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 877 NULL, &lockstate); 878 if (def == NULL) 879 rtld_die(); 880 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 881 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 882 else 883 target = (Elf_Addr)(defobj->relocbase + def->st_value); 884 885 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 886 defobj->strtab + def->st_name, basename(obj->path), 887 (void *)target, basename(defobj->path)); 888 889 /* 890 * Write the new contents for the jmpslot. Note that depending on 891 * architecture, the value which we need to return back to the 892 * lazy binding trampoline may or may not be the target 893 * address. The value returned from reloc_jmpslot() is the value 894 * that the trampoline needs. 895 */ 896 target = reloc_jmpslot(where, target, defobj, obj, rel); 897 lock_release(rtld_bind_lock, &lockstate); 898 return target; 899 } 900 901 /* 902 * Error reporting function. Use it like printf. If formats the message 903 * into a buffer, and sets things up so that the next call to dlerror() 904 * will return the message. 905 */ 906 void 907 _rtld_error(const char *fmt, ...) 908 { 909 static char buf[512]; 910 va_list ap; 911 912 va_start(ap, fmt); 913 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 914 error_message = buf; 915 va_end(ap); 916 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 917 } 918 919 /* 920 * Return a dynamically-allocated copy of the current error message, if any. 921 */ 922 static char * 923 errmsg_save(void) 924 { 925 return error_message == NULL ? NULL : xstrdup(error_message); 926 } 927 928 /* 929 * Restore the current error message from a copy which was previously saved 930 * by errmsg_save(). The copy is freed. 931 */ 932 static void 933 errmsg_restore(char *saved_msg) 934 { 935 if (saved_msg == NULL) 936 error_message = NULL; 937 else { 938 _rtld_error("%s", saved_msg); 939 free(saved_msg); 940 } 941 } 942 943 static const char * 944 basename(const char *name) 945 { 946 const char *p = strrchr(name, '/'); 947 return p != NULL ? p + 1 : name; 948 } 949 950 static struct utsname uts; 951 952 static char * 953 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 954 const char *subst, bool may_free) 955 { 956 char *p, *p1, *res, *resp; 957 int subst_len, kw_len, subst_count, old_len, new_len; 958 959 kw_len = strlen(kw); 960 961 /* 962 * First, count the number of the keyword occurrences, to 963 * preallocate the final string. 964 */ 965 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 966 p1 = strstr(p, kw); 967 if (p1 == NULL) 968 break; 969 } 970 971 /* 972 * If the keyword is not found, just return. 973 * 974 * Return non-substituted string if resolution failed. We 975 * cannot do anything more reasonable, the failure mode of the 976 * caller is unresolved library anyway. 977 */ 978 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 979 return (may_free ? real : xstrdup(real)); 980 if (obj != NULL) 981 subst = obj->origin_path; 982 983 /* 984 * There is indeed something to substitute. Calculate the 985 * length of the resulting string, and allocate it. 986 */ 987 subst_len = strlen(subst); 988 old_len = strlen(real); 989 new_len = old_len + (subst_len - kw_len) * subst_count; 990 res = xmalloc(new_len + 1); 991 992 /* 993 * Now, execute the substitution loop. 994 */ 995 for (p = real, resp = res, *resp = '\0';;) { 996 p1 = strstr(p, kw); 997 if (p1 != NULL) { 998 /* Copy the prefix before keyword. */ 999 memcpy(resp, p, p1 - p); 1000 resp += p1 - p; 1001 /* Keyword replacement. */ 1002 memcpy(resp, subst, subst_len); 1003 resp += subst_len; 1004 *resp = '\0'; 1005 p = p1 + kw_len; 1006 } else 1007 break; 1008 } 1009 1010 /* Copy to the end of string and finish. */ 1011 strcat(resp, p); 1012 if (may_free) 1013 free(real); 1014 return (res); 1015 } 1016 1017 static char * 1018 origin_subst(Obj_Entry *obj, const char *real) 1019 { 1020 char *res1, *res2, *res3, *res4; 1021 1022 if (obj == NULL || !trust) 1023 return (xstrdup(real)); 1024 if (uts.sysname[0] == '\0') { 1025 if (uname(&uts) != 0) { 1026 _rtld_error("utsname failed: %d", errno); 1027 return (NULL); 1028 } 1029 } 1030 /* __DECONST is safe here since without may_free real is unchanged */ 1031 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1032 false); 1033 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1034 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1035 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1036 return (res4); 1037 } 1038 1039 void 1040 rtld_die(void) 1041 { 1042 const char *msg = dlerror(); 1043 1044 if (msg == NULL) 1045 msg = "Fatal error"; 1046 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1047 rtld_fdputstr(STDERR_FILENO, msg); 1048 rtld_fdputchar(STDERR_FILENO, '\n'); 1049 _exit(1); 1050 } 1051 1052 /* 1053 * Process a shared object's DYNAMIC section, and save the important 1054 * information in its Obj_Entry structure. 1055 */ 1056 static void 1057 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1058 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1059 { 1060 const Elf_Dyn *dynp; 1061 Needed_Entry **needed_tail = &obj->needed; 1062 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1063 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1064 const Elf_Hashelt *hashtab; 1065 const Elf32_Word *hashval; 1066 Elf32_Word bkt, nmaskwords; 1067 int bloom_size32; 1068 int plttype = DT_REL; 1069 1070 *dyn_rpath = NULL; 1071 *dyn_soname = NULL; 1072 *dyn_runpath = NULL; 1073 1074 obj->bind_now = false; 1075 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1076 switch (dynp->d_tag) { 1077 1078 case DT_REL: 1079 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1080 break; 1081 1082 case DT_RELSZ: 1083 obj->relsize = dynp->d_un.d_val; 1084 break; 1085 1086 case DT_RELENT: 1087 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1088 break; 1089 1090 case DT_JMPREL: 1091 obj->pltrel = (const Elf_Rel *) 1092 (obj->relocbase + dynp->d_un.d_ptr); 1093 break; 1094 1095 case DT_PLTRELSZ: 1096 obj->pltrelsize = dynp->d_un.d_val; 1097 break; 1098 1099 case DT_RELA: 1100 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1101 break; 1102 1103 case DT_RELASZ: 1104 obj->relasize = dynp->d_un.d_val; 1105 break; 1106 1107 case DT_RELAENT: 1108 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1109 break; 1110 1111 case DT_PLTREL: 1112 plttype = dynp->d_un.d_val; 1113 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1114 break; 1115 1116 case DT_SYMTAB: 1117 obj->symtab = (const Elf_Sym *) 1118 (obj->relocbase + dynp->d_un.d_ptr); 1119 break; 1120 1121 case DT_SYMENT: 1122 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1123 break; 1124 1125 case DT_STRTAB: 1126 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1127 break; 1128 1129 case DT_STRSZ: 1130 obj->strsize = dynp->d_un.d_val; 1131 break; 1132 1133 case DT_VERNEED: 1134 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1135 dynp->d_un.d_val); 1136 break; 1137 1138 case DT_VERNEEDNUM: 1139 obj->verneednum = dynp->d_un.d_val; 1140 break; 1141 1142 case DT_VERDEF: 1143 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1144 dynp->d_un.d_val); 1145 break; 1146 1147 case DT_VERDEFNUM: 1148 obj->verdefnum = dynp->d_un.d_val; 1149 break; 1150 1151 case DT_VERSYM: 1152 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1153 dynp->d_un.d_val); 1154 break; 1155 1156 case DT_HASH: 1157 { 1158 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1159 dynp->d_un.d_ptr); 1160 obj->nbuckets = hashtab[0]; 1161 obj->nchains = hashtab[1]; 1162 obj->buckets = hashtab + 2; 1163 obj->chains = obj->buckets + obj->nbuckets; 1164 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1165 obj->buckets != NULL; 1166 } 1167 break; 1168 1169 case DT_GNU_HASH: 1170 { 1171 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1172 dynp->d_un.d_ptr); 1173 obj->nbuckets_gnu = hashtab[0]; 1174 obj->symndx_gnu = hashtab[1]; 1175 nmaskwords = hashtab[2]; 1176 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1177 obj->maskwords_bm_gnu = nmaskwords - 1; 1178 obj->shift2_gnu = hashtab[3]; 1179 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1180 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1181 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1182 obj->symndx_gnu; 1183 /* Number of bitmask words is required to be power of 2 */ 1184 obj->valid_hash_gnu = powerof2(nmaskwords) && 1185 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1186 } 1187 break; 1188 1189 case DT_NEEDED: 1190 if (!obj->rtld) { 1191 Needed_Entry *nep = NEW(Needed_Entry); 1192 nep->name = dynp->d_un.d_val; 1193 nep->obj = NULL; 1194 nep->next = NULL; 1195 1196 *needed_tail = nep; 1197 needed_tail = &nep->next; 1198 } 1199 break; 1200 1201 case DT_FILTER: 1202 if (!obj->rtld) { 1203 Needed_Entry *nep = NEW(Needed_Entry); 1204 nep->name = dynp->d_un.d_val; 1205 nep->obj = NULL; 1206 nep->next = NULL; 1207 1208 *needed_filtees_tail = nep; 1209 needed_filtees_tail = &nep->next; 1210 } 1211 break; 1212 1213 case DT_AUXILIARY: 1214 if (!obj->rtld) { 1215 Needed_Entry *nep = NEW(Needed_Entry); 1216 nep->name = dynp->d_un.d_val; 1217 nep->obj = NULL; 1218 nep->next = NULL; 1219 1220 *needed_aux_filtees_tail = nep; 1221 needed_aux_filtees_tail = &nep->next; 1222 } 1223 break; 1224 1225 case DT_PLTGOT: 1226 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1227 break; 1228 1229 case DT_TEXTREL: 1230 obj->textrel = true; 1231 break; 1232 1233 case DT_SYMBOLIC: 1234 obj->symbolic = true; 1235 break; 1236 1237 case DT_RPATH: 1238 /* 1239 * We have to wait until later to process this, because we 1240 * might not have gotten the address of the string table yet. 1241 */ 1242 *dyn_rpath = dynp; 1243 break; 1244 1245 case DT_SONAME: 1246 *dyn_soname = dynp; 1247 break; 1248 1249 case DT_RUNPATH: 1250 *dyn_runpath = dynp; 1251 break; 1252 1253 case DT_INIT: 1254 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1255 break; 1256 1257 case DT_PREINIT_ARRAY: 1258 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1259 break; 1260 1261 case DT_PREINIT_ARRAYSZ: 1262 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1263 break; 1264 1265 case DT_INIT_ARRAY: 1266 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1267 break; 1268 1269 case DT_INIT_ARRAYSZ: 1270 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1271 break; 1272 1273 case DT_FINI: 1274 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1275 break; 1276 1277 case DT_FINI_ARRAY: 1278 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1279 break; 1280 1281 case DT_FINI_ARRAYSZ: 1282 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1283 break; 1284 1285 /* 1286 * Don't process DT_DEBUG on MIPS as the dynamic section 1287 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1288 */ 1289 1290 #ifndef __mips__ 1291 case DT_DEBUG: 1292 if (!early) 1293 dbg("Filling in DT_DEBUG entry"); 1294 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1295 break; 1296 #endif 1297 1298 case DT_FLAGS: 1299 if (dynp->d_un.d_val & DF_ORIGIN) 1300 obj->z_origin = true; 1301 if (dynp->d_un.d_val & DF_SYMBOLIC) 1302 obj->symbolic = true; 1303 if (dynp->d_un.d_val & DF_TEXTREL) 1304 obj->textrel = true; 1305 if (dynp->d_un.d_val & DF_BIND_NOW) 1306 obj->bind_now = true; 1307 if (dynp->d_un.d_val & DF_STATIC_TLS) 1308 obj->static_tls = true; 1309 break; 1310 #ifdef __mips__ 1311 case DT_MIPS_LOCAL_GOTNO: 1312 obj->local_gotno = dynp->d_un.d_val; 1313 break; 1314 1315 case DT_MIPS_SYMTABNO: 1316 obj->symtabno = dynp->d_un.d_val; 1317 break; 1318 1319 case DT_MIPS_GOTSYM: 1320 obj->gotsym = dynp->d_un.d_val; 1321 break; 1322 1323 case DT_MIPS_RLD_MAP: 1324 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1325 break; 1326 1327 case DT_MIPS_RLD_MAP_REL: 1328 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1329 // section relative to the address of the tag itself. 1330 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1331 (Elf_Addr) &r_debug; 1332 break; 1333 1334 case DT_MIPS_PLTGOT: 1335 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1336 dynp->d_un.d_ptr); 1337 break; 1338 1339 #endif 1340 1341 #ifdef __powerpc__ 1342 #ifdef __powerpc64__ 1343 case DT_PPC64_GLINK: 1344 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1345 break; 1346 #else 1347 case DT_PPC_GOT: 1348 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1349 break; 1350 #endif 1351 #endif 1352 1353 case DT_FLAGS_1: 1354 if (dynp->d_un.d_val & DF_1_NOOPEN) 1355 obj->z_noopen = true; 1356 if (dynp->d_un.d_val & DF_1_ORIGIN) 1357 obj->z_origin = true; 1358 if (dynp->d_un.d_val & DF_1_GLOBAL) 1359 obj->z_global = true; 1360 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1361 obj->bind_now = true; 1362 if (dynp->d_un.d_val & DF_1_NODELETE) 1363 obj->z_nodelete = true; 1364 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1365 obj->z_loadfltr = true; 1366 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1367 obj->z_interpose = true; 1368 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1369 obj->z_nodeflib = true; 1370 break; 1371 1372 default: 1373 if (!early) { 1374 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1375 (long)dynp->d_tag); 1376 } 1377 break; 1378 } 1379 } 1380 1381 obj->traced = false; 1382 1383 if (plttype == DT_RELA) { 1384 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1385 obj->pltrel = NULL; 1386 obj->pltrelasize = obj->pltrelsize; 1387 obj->pltrelsize = 0; 1388 } 1389 1390 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1391 if (obj->valid_hash_sysv) 1392 obj->dynsymcount = obj->nchains; 1393 else if (obj->valid_hash_gnu) { 1394 obj->dynsymcount = 0; 1395 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1396 if (obj->buckets_gnu[bkt] == 0) 1397 continue; 1398 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1399 do 1400 obj->dynsymcount++; 1401 while ((*hashval++ & 1u) == 0); 1402 } 1403 obj->dynsymcount += obj->symndx_gnu; 1404 } 1405 } 1406 1407 static bool 1408 obj_resolve_origin(Obj_Entry *obj) 1409 { 1410 1411 if (obj->origin_path != NULL) 1412 return (true); 1413 obj->origin_path = xmalloc(PATH_MAX); 1414 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1415 } 1416 1417 static bool 1418 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1419 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1420 { 1421 1422 if (obj->z_origin && !obj_resolve_origin(obj)) 1423 return (false); 1424 1425 if (dyn_runpath != NULL) { 1426 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1427 obj->runpath = origin_subst(obj, obj->runpath); 1428 } else if (dyn_rpath != NULL) { 1429 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1430 obj->rpath = origin_subst(obj, obj->rpath); 1431 } 1432 if (dyn_soname != NULL) 1433 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1434 return (true); 1435 } 1436 1437 static bool 1438 digest_dynamic(Obj_Entry *obj, int early) 1439 { 1440 const Elf_Dyn *dyn_rpath; 1441 const Elf_Dyn *dyn_soname; 1442 const Elf_Dyn *dyn_runpath; 1443 1444 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1445 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1446 } 1447 1448 /* 1449 * Process a shared object's program header. This is used only for the 1450 * main program, when the kernel has already loaded the main program 1451 * into memory before calling the dynamic linker. It creates and 1452 * returns an Obj_Entry structure. 1453 */ 1454 static Obj_Entry * 1455 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1456 { 1457 Obj_Entry *obj; 1458 const Elf_Phdr *phlimit = phdr + phnum; 1459 const Elf_Phdr *ph; 1460 Elf_Addr note_start, note_end; 1461 int nsegs = 0; 1462 1463 obj = obj_new(); 1464 for (ph = phdr; ph < phlimit; ph++) { 1465 if (ph->p_type != PT_PHDR) 1466 continue; 1467 1468 obj->phdr = phdr; 1469 obj->phsize = ph->p_memsz; 1470 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1471 break; 1472 } 1473 1474 obj->stack_flags = PF_X | PF_R | PF_W; 1475 1476 for (ph = phdr; ph < phlimit; ph++) { 1477 switch (ph->p_type) { 1478 1479 case PT_INTERP: 1480 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1481 break; 1482 1483 case PT_LOAD: 1484 if (nsegs == 0) { /* First load segment */ 1485 obj->vaddrbase = trunc_page(ph->p_vaddr); 1486 obj->mapbase = obj->vaddrbase + obj->relocbase; 1487 } else { /* Last load segment */ 1488 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1489 obj->vaddrbase; 1490 } 1491 nsegs++; 1492 break; 1493 1494 case PT_DYNAMIC: 1495 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1496 break; 1497 1498 case PT_TLS: 1499 obj->tlsindex = 1; 1500 obj->tlssize = ph->p_memsz; 1501 obj->tlsalign = ph->p_align; 1502 obj->tlsinitsize = ph->p_filesz; 1503 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1504 obj->tlspoffset = ph->p_offset; 1505 break; 1506 1507 case PT_GNU_STACK: 1508 obj->stack_flags = ph->p_flags; 1509 break; 1510 1511 case PT_GNU_RELRO: 1512 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1513 obj->relro_size = round_page(ph->p_memsz); 1514 break; 1515 1516 case PT_NOTE: 1517 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1518 note_end = note_start + ph->p_filesz; 1519 digest_notes(obj, note_start, note_end); 1520 break; 1521 } 1522 } 1523 if (nsegs < 1) { 1524 _rtld_error("%s: too few PT_LOAD segments", path); 1525 return NULL; 1526 } 1527 1528 obj->entry = entry; 1529 return obj; 1530 } 1531 1532 void 1533 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1534 { 1535 const Elf_Note *note; 1536 const char *note_name; 1537 uintptr_t p; 1538 1539 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1540 note = (const Elf_Note *)((const char *)(note + 1) + 1541 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1542 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1543 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1544 note->n_descsz != sizeof(int32_t)) 1545 continue; 1546 if (note->n_type != NT_FREEBSD_ABI_TAG && 1547 note->n_type != NT_FREEBSD_FEATURE_CTL && 1548 note->n_type != NT_FREEBSD_NOINIT_TAG) 1549 continue; 1550 note_name = (const char *)(note + 1); 1551 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1552 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1553 continue; 1554 switch (note->n_type) { 1555 case NT_FREEBSD_ABI_TAG: 1556 /* FreeBSD osrel note */ 1557 p = (uintptr_t)(note + 1); 1558 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1559 obj->osrel = *(const int32_t *)(p); 1560 dbg("note osrel %d", obj->osrel); 1561 break; 1562 case NT_FREEBSD_FEATURE_CTL: 1563 /* FreeBSD ABI feature control note */ 1564 p = (uintptr_t)(note + 1); 1565 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1566 obj->fctl0 = *(const uint32_t *)(p); 1567 dbg("note fctl0 %#x", obj->fctl0); 1568 break; 1569 case NT_FREEBSD_NOINIT_TAG: 1570 /* FreeBSD 'crt does not call init' note */ 1571 obj->crt_no_init = true; 1572 dbg("note crt_no_init"); 1573 break; 1574 } 1575 } 1576 } 1577 1578 static Obj_Entry * 1579 dlcheck(void *handle) 1580 { 1581 Obj_Entry *obj; 1582 1583 TAILQ_FOREACH(obj, &obj_list, next) { 1584 if (obj == (Obj_Entry *) handle) 1585 break; 1586 } 1587 1588 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1589 _rtld_error("Invalid shared object handle %p", handle); 1590 return NULL; 1591 } 1592 return obj; 1593 } 1594 1595 /* 1596 * If the given object is already in the donelist, return true. Otherwise 1597 * add the object to the list and return false. 1598 */ 1599 static bool 1600 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1601 { 1602 unsigned int i; 1603 1604 for (i = 0; i < dlp->num_used; i++) 1605 if (dlp->objs[i] == obj) 1606 return true; 1607 /* 1608 * Our donelist allocation should always be sufficient. But if 1609 * our threads locking isn't working properly, more shared objects 1610 * could have been loaded since we allocated the list. That should 1611 * never happen, but we'll handle it properly just in case it does. 1612 */ 1613 if (dlp->num_used < dlp->num_alloc) 1614 dlp->objs[dlp->num_used++] = obj; 1615 return false; 1616 } 1617 1618 /* 1619 * Hash function for symbol table lookup. Don't even think about changing 1620 * this. It is specified by the System V ABI. 1621 */ 1622 unsigned long 1623 elf_hash(const char *name) 1624 { 1625 const unsigned char *p = (const unsigned char *) name; 1626 unsigned long h = 0; 1627 unsigned long g; 1628 1629 while (*p != '\0') { 1630 h = (h << 4) + *p++; 1631 if ((g = h & 0xf0000000) != 0) 1632 h ^= g >> 24; 1633 h &= ~g; 1634 } 1635 return h; 1636 } 1637 1638 /* 1639 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1640 * unsigned in case it's implemented with a wider type. 1641 */ 1642 static uint32_t 1643 gnu_hash(const char *s) 1644 { 1645 uint32_t h; 1646 unsigned char c; 1647 1648 h = 5381; 1649 for (c = *s; c != '\0'; c = *++s) 1650 h = h * 33 + c; 1651 return (h & 0xffffffff); 1652 } 1653 1654 1655 /* 1656 * Find the library with the given name, and return its full pathname. 1657 * The returned string is dynamically allocated. Generates an error 1658 * message and returns NULL if the library cannot be found. 1659 * 1660 * If the second argument is non-NULL, then it refers to an already- 1661 * loaded shared object, whose library search path will be searched. 1662 * 1663 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1664 * descriptor (which is close-on-exec) will be passed out via the third 1665 * argument. 1666 * 1667 * The search order is: 1668 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1669 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1670 * LD_LIBRARY_PATH 1671 * DT_RUNPATH in the referencing file 1672 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1673 * from list) 1674 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1675 * 1676 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1677 */ 1678 static char * 1679 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1680 { 1681 char *pathname, *refobj_path; 1682 const char *name; 1683 bool nodeflib, objgiven; 1684 1685 objgiven = refobj != NULL; 1686 1687 if (libmap_disable || !objgiven || 1688 (name = lm_find(refobj->path, xname)) == NULL) 1689 name = xname; 1690 1691 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1692 if (name[0] != '/' && !trust) { 1693 _rtld_error("Absolute pathname required " 1694 "for shared object \"%s\"", name); 1695 return (NULL); 1696 } 1697 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1698 __DECONST(char *, name))); 1699 } 1700 1701 dbg(" Searching for \"%s\"", name); 1702 refobj_path = objgiven ? refobj->path : NULL; 1703 1704 /* 1705 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1706 * back to pre-conforming behaviour if user requested so with 1707 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1708 * nodeflib. 1709 */ 1710 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1711 pathname = search_library_path(name, ld_library_path, 1712 refobj_path, fdp); 1713 if (pathname != NULL) 1714 return (pathname); 1715 if (refobj != NULL) { 1716 pathname = search_library_path(name, refobj->rpath, 1717 refobj_path, fdp); 1718 if (pathname != NULL) 1719 return (pathname); 1720 } 1721 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1722 if (pathname != NULL) 1723 return (pathname); 1724 pathname = search_library_path(name, gethints(false), 1725 refobj_path, fdp); 1726 if (pathname != NULL) 1727 return (pathname); 1728 pathname = search_library_path(name, ld_standard_library_path, 1729 refobj_path, fdp); 1730 if (pathname != NULL) 1731 return (pathname); 1732 } else { 1733 nodeflib = objgiven ? refobj->z_nodeflib : false; 1734 if (objgiven) { 1735 pathname = search_library_path(name, refobj->rpath, 1736 refobj->path, fdp); 1737 if (pathname != NULL) 1738 return (pathname); 1739 } 1740 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1741 pathname = search_library_path(name, obj_main->rpath, 1742 refobj_path, fdp); 1743 if (pathname != NULL) 1744 return (pathname); 1745 } 1746 pathname = search_library_path(name, ld_library_path, 1747 refobj_path, fdp); 1748 if (pathname != NULL) 1749 return (pathname); 1750 if (objgiven) { 1751 pathname = search_library_path(name, refobj->runpath, 1752 refobj_path, fdp); 1753 if (pathname != NULL) 1754 return (pathname); 1755 } 1756 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1757 if (pathname != NULL) 1758 return (pathname); 1759 pathname = search_library_path(name, gethints(nodeflib), 1760 refobj_path, fdp); 1761 if (pathname != NULL) 1762 return (pathname); 1763 if (objgiven && !nodeflib) { 1764 pathname = search_library_path(name, 1765 ld_standard_library_path, refobj_path, fdp); 1766 if (pathname != NULL) 1767 return (pathname); 1768 } 1769 } 1770 1771 if (objgiven && refobj->path != NULL) { 1772 _rtld_error("Shared object \"%s\" not found, " 1773 "required by \"%s\"", name, basename(refobj->path)); 1774 } else { 1775 _rtld_error("Shared object \"%s\" not found", name); 1776 } 1777 return (NULL); 1778 } 1779 1780 /* 1781 * Given a symbol number in a referencing object, find the corresponding 1782 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1783 * no definition was found. Returns a pointer to the Obj_Entry of the 1784 * defining object via the reference parameter DEFOBJ_OUT. 1785 */ 1786 const Elf_Sym * 1787 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1788 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1789 RtldLockState *lockstate) 1790 { 1791 const Elf_Sym *ref; 1792 const Elf_Sym *def; 1793 const Obj_Entry *defobj; 1794 const Ver_Entry *ve; 1795 SymLook req; 1796 const char *name; 1797 int res; 1798 1799 /* 1800 * If we have already found this symbol, get the information from 1801 * the cache. 1802 */ 1803 if (symnum >= refobj->dynsymcount) 1804 return NULL; /* Bad object */ 1805 if (cache != NULL && cache[symnum].sym != NULL) { 1806 *defobj_out = cache[symnum].obj; 1807 return cache[symnum].sym; 1808 } 1809 1810 ref = refobj->symtab + symnum; 1811 name = refobj->strtab + ref->st_name; 1812 def = NULL; 1813 defobj = NULL; 1814 ve = NULL; 1815 1816 /* 1817 * We don't have to do a full scale lookup if the symbol is local. 1818 * We know it will bind to the instance in this load module; to 1819 * which we already have a pointer (ie ref). By not doing a lookup, 1820 * we not only improve performance, but it also avoids unresolvable 1821 * symbols when local symbols are not in the hash table. This has 1822 * been seen with the ia64 toolchain. 1823 */ 1824 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1825 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1826 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1827 symnum); 1828 } 1829 symlook_init(&req, name); 1830 req.flags = flags; 1831 ve = req.ventry = fetch_ventry(refobj, symnum); 1832 req.lockstate = lockstate; 1833 res = symlook_default(&req, refobj); 1834 if (res == 0) { 1835 def = req.sym_out; 1836 defobj = req.defobj_out; 1837 } 1838 } else { 1839 def = ref; 1840 defobj = refobj; 1841 } 1842 1843 /* 1844 * If we found no definition and the reference is weak, treat the 1845 * symbol as having the value zero. 1846 */ 1847 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1848 def = &sym_zero; 1849 defobj = obj_main; 1850 } 1851 1852 if (def != NULL) { 1853 *defobj_out = defobj; 1854 /* Record the information in the cache to avoid subsequent lookups. */ 1855 if (cache != NULL) { 1856 cache[symnum].sym = def; 1857 cache[symnum].obj = defobj; 1858 } 1859 } else { 1860 if (refobj != &obj_rtld) 1861 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1862 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1863 } 1864 return def; 1865 } 1866 1867 /* 1868 * Return the search path from the ldconfig hints file, reading it if 1869 * necessary. If nostdlib is true, then the default search paths are 1870 * not added to result. 1871 * 1872 * Returns NULL if there are problems with the hints file, 1873 * or if the search path there is empty. 1874 */ 1875 static const char * 1876 gethints(bool nostdlib) 1877 { 1878 static char *filtered_path; 1879 static const char *hints; 1880 static struct elfhints_hdr hdr; 1881 struct fill_search_info_args sargs, hargs; 1882 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1883 struct dl_serpath *SLPpath, *hintpath; 1884 char *p; 1885 struct stat hint_stat; 1886 unsigned int SLPndx, hintndx, fndx, fcount; 1887 int fd; 1888 size_t flen; 1889 uint32_t dl; 1890 bool skip; 1891 1892 /* First call, read the hints file */ 1893 if (hints == NULL) { 1894 /* Keep from trying again in case the hints file is bad. */ 1895 hints = ""; 1896 1897 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1898 return (NULL); 1899 1900 /* 1901 * Check of hdr.dirlistlen value against type limit 1902 * intends to pacify static analyzers. Further 1903 * paranoia leads to checks that dirlist is fully 1904 * contained in the file range. 1905 */ 1906 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1907 hdr.magic != ELFHINTS_MAGIC || 1908 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1909 fstat(fd, &hint_stat) == -1) { 1910 cleanup1: 1911 close(fd); 1912 hdr.dirlistlen = 0; 1913 return (NULL); 1914 } 1915 dl = hdr.strtab; 1916 if (dl + hdr.dirlist < dl) 1917 goto cleanup1; 1918 dl += hdr.dirlist; 1919 if (dl + hdr.dirlistlen < dl) 1920 goto cleanup1; 1921 dl += hdr.dirlistlen; 1922 if (dl > hint_stat.st_size) 1923 goto cleanup1; 1924 p = xmalloc(hdr.dirlistlen + 1); 1925 if (pread(fd, p, hdr.dirlistlen + 1, 1926 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1927 p[hdr.dirlistlen] != '\0') { 1928 free(p); 1929 goto cleanup1; 1930 } 1931 hints = p; 1932 close(fd); 1933 } 1934 1935 /* 1936 * If caller agreed to receive list which includes the default 1937 * paths, we are done. Otherwise, if we still did not 1938 * calculated filtered result, do it now. 1939 */ 1940 if (!nostdlib) 1941 return (hints[0] != '\0' ? hints : NULL); 1942 if (filtered_path != NULL) 1943 goto filt_ret; 1944 1945 /* 1946 * Obtain the list of all configured search paths, and the 1947 * list of the default paths. 1948 * 1949 * First estimate the size of the results. 1950 */ 1951 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1952 smeta.dls_cnt = 0; 1953 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1954 hmeta.dls_cnt = 0; 1955 1956 sargs.request = RTLD_DI_SERINFOSIZE; 1957 sargs.serinfo = &smeta; 1958 hargs.request = RTLD_DI_SERINFOSIZE; 1959 hargs.serinfo = &hmeta; 1960 1961 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1962 &sargs); 1963 path_enumerate(hints, fill_search_info, NULL, &hargs); 1964 1965 SLPinfo = xmalloc(smeta.dls_size); 1966 hintinfo = xmalloc(hmeta.dls_size); 1967 1968 /* 1969 * Next fetch both sets of paths. 1970 */ 1971 sargs.request = RTLD_DI_SERINFO; 1972 sargs.serinfo = SLPinfo; 1973 sargs.serpath = &SLPinfo->dls_serpath[0]; 1974 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1975 1976 hargs.request = RTLD_DI_SERINFO; 1977 hargs.serinfo = hintinfo; 1978 hargs.serpath = &hintinfo->dls_serpath[0]; 1979 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1980 1981 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1982 &sargs); 1983 path_enumerate(hints, fill_search_info, NULL, &hargs); 1984 1985 /* 1986 * Now calculate the difference between two sets, by excluding 1987 * standard paths from the full set. 1988 */ 1989 fndx = 0; 1990 fcount = 0; 1991 filtered_path = xmalloc(hdr.dirlistlen + 1); 1992 hintpath = &hintinfo->dls_serpath[0]; 1993 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1994 skip = false; 1995 SLPpath = &SLPinfo->dls_serpath[0]; 1996 /* 1997 * Check each standard path against current. 1998 */ 1999 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2000 /* matched, skip the path */ 2001 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2002 skip = true; 2003 break; 2004 } 2005 } 2006 if (skip) 2007 continue; 2008 /* 2009 * Not matched against any standard path, add the path 2010 * to result. Separate consequtive paths with ':'. 2011 */ 2012 if (fcount > 0) { 2013 filtered_path[fndx] = ':'; 2014 fndx++; 2015 } 2016 fcount++; 2017 flen = strlen(hintpath->dls_name); 2018 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2019 fndx += flen; 2020 } 2021 filtered_path[fndx] = '\0'; 2022 2023 free(SLPinfo); 2024 free(hintinfo); 2025 2026 filt_ret: 2027 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2028 } 2029 2030 static void 2031 init_dag(Obj_Entry *root) 2032 { 2033 const Needed_Entry *needed; 2034 const Objlist_Entry *elm; 2035 DoneList donelist; 2036 2037 if (root->dag_inited) 2038 return; 2039 donelist_init(&donelist); 2040 2041 /* Root object belongs to own DAG. */ 2042 objlist_push_tail(&root->dldags, root); 2043 objlist_push_tail(&root->dagmembers, root); 2044 donelist_check(&donelist, root); 2045 2046 /* 2047 * Add dependencies of root object to DAG in breadth order 2048 * by exploiting the fact that each new object get added 2049 * to the tail of the dagmembers list. 2050 */ 2051 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2052 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2053 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2054 continue; 2055 objlist_push_tail(&needed->obj->dldags, root); 2056 objlist_push_tail(&root->dagmembers, needed->obj); 2057 } 2058 } 2059 root->dag_inited = true; 2060 } 2061 2062 static void 2063 init_marker(Obj_Entry *marker) 2064 { 2065 2066 bzero(marker, sizeof(*marker)); 2067 marker->marker = true; 2068 } 2069 2070 Obj_Entry * 2071 globallist_curr(const Obj_Entry *obj) 2072 { 2073 2074 for (;;) { 2075 if (obj == NULL) 2076 return (NULL); 2077 if (!obj->marker) 2078 return (__DECONST(Obj_Entry *, obj)); 2079 obj = TAILQ_PREV(obj, obj_entry_q, next); 2080 } 2081 } 2082 2083 Obj_Entry * 2084 globallist_next(const Obj_Entry *obj) 2085 { 2086 2087 for (;;) { 2088 obj = TAILQ_NEXT(obj, next); 2089 if (obj == NULL) 2090 return (NULL); 2091 if (!obj->marker) 2092 return (__DECONST(Obj_Entry *, obj)); 2093 } 2094 } 2095 2096 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2097 static void 2098 hold_object(Obj_Entry *obj) 2099 { 2100 2101 obj->holdcount++; 2102 } 2103 2104 static void 2105 unhold_object(Obj_Entry *obj) 2106 { 2107 2108 assert(obj->holdcount > 0); 2109 if (--obj->holdcount == 0 && obj->unholdfree) 2110 release_object(obj); 2111 } 2112 2113 static void 2114 process_z(Obj_Entry *root) 2115 { 2116 const Objlist_Entry *elm; 2117 Obj_Entry *obj; 2118 2119 /* 2120 * Walk over object DAG and process every dependent object 2121 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2122 * to grow their own DAG. 2123 * 2124 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2125 * symlook_global() to work. 2126 * 2127 * For DF_1_NODELETE, the DAG should have its reference upped. 2128 */ 2129 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2130 obj = elm->obj; 2131 if (obj == NULL) 2132 continue; 2133 if (obj->z_nodelete && !obj->ref_nodel) { 2134 dbg("obj %s -z nodelete", obj->path); 2135 init_dag(obj); 2136 ref_dag(obj); 2137 obj->ref_nodel = true; 2138 } 2139 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2140 dbg("obj %s -z global", obj->path); 2141 objlist_push_tail(&list_global, obj); 2142 init_dag(obj); 2143 } 2144 } 2145 } 2146 /* 2147 * Initialize the dynamic linker. The argument is the address at which 2148 * the dynamic linker has been mapped into memory. The primary task of 2149 * this function is to relocate the dynamic linker. 2150 */ 2151 static void 2152 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2153 { 2154 Obj_Entry objtmp; /* Temporary rtld object */ 2155 const Elf_Ehdr *ehdr; 2156 const Elf_Dyn *dyn_rpath; 2157 const Elf_Dyn *dyn_soname; 2158 const Elf_Dyn *dyn_runpath; 2159 2160 #ifdef RTLD_INIT_PAGESIZES_EARLY 2161 /* The page size is required by the dynamic memory allocator. */ 2162 init_pagesizes(aux_info); 2163 #endif 2164 2165 /* 2166 * Conjure up an Obj_Entry structure for the dynamic linker. 2167 * 2168 * The "path" member can't be initialized yet because string constants 2169 * cannot yet be accessed. Below we will set it correctly. 2170 */ 2171 memset(&objtmp, 0, sizeof(objtmp)); 2172 objtmp.path = NULL; 2173 objtmp.rtld = true; 2174 objtmp.mapbase = mapbase; 2175 #ifdef PIC 2176 objtmp.relocbase = mapbase; 2177 #endif 2178 2179 objtmp.dynamic = rtld_dynamic(&objtmp); 2180 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2181 assert(objtmp.needed == NULL); 2182 #if !defined(__mips__) 2183 /* MIPS has a bogus DT_TEXTREL. */ 2184 assert(!objtmp.textrel); 2185 #endif 2186 /* 2187 * Temporarily put the dynamic linker entry into the object list, so 2188 * that symbols can be found. 2189 */ 2190 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2191 2192 ehdr = (Elf_Ehdr *)mapbase; 2193 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2194 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2195 2196 /* Initialize the object list. */ 2197 TAILQ_INIT(&obj_list); 2198 2199 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2200 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2201 2202 #ifndef RTLD_INIT_PAGESIZES_EARLY 2203 /* The page size is required by the dynamic memory allocator. */ 2204 init_pagesizes(aux_info); 2205 #endif 2206 2207 if (aux_info[AT_OSRELDATE] != NULL) 2208 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2209 2210 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2211 2212 /* Replace the path with a dynamically allocated copy. */ 2213 obj_rtld.path = xstrdup(ld_path_rtld); 2214 2215 r_debug.r_brk = r_debug_state; 2216 r_debug.r_state = RT_CONSISTENT; 2217 } 2218 2219 /* 2220 * Retrieve the array of supported page sizes. The kernel provides the page 2221 * sizes in increasing order. 2222 */ 2223 static void 2224 init_pagesizes(Elf_Auxinfo **aux_info) 2225 { 2226 static size_t psa[MAXPAGESIZES]; 2227 int mib[2]; 2228 size_t len, size; 2229 2230 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2231 NULL) { 2232 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2233 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2234 } else { 2235 len = 2; 2236 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2237 size = sizeof(psa); 2238 else { 2239 /* As a fallback, retrieve the base page size. */ 2240 size = sizeof(psa[0]); 2241 if (aux_info[AT_PAGESZ] != NULL) { 2242 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2243 goto psa_filled; 2244 } else { 2245 mib[0] = CTL_HW; 2246 mib[1] = HW_PAGESIZE; 2247 len = 2; 2248 } 2249 } 2250 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2251 _rtld_error("sysctl for hw.pagesize(s) failed"); 2252 rtld_die(); 2253 } 2254 psa_filled: 2255 pagesizes = psa; 2256 } 2257 npagesizes = size / sizeof(pagesizes[0]); 2258 /* Discard any invalid entries at the end of the array. */ 2259 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2260 npagesizes--; 2261 } 2262 2263 /* 2264 * Add the init functions from a needed object list (and its recursive 2265 * needed objects) to "list". This is not used directly; it is a helper 2266 * function for initlist_add_objects(). The write lock must be held 2267 * when this function is called. 2268 */ 2269 static void 2270 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2271 { 2272 /* Recursively process the successor needed objects. */ 2273 if (needed->next != NULL) 2274 initlist_add_neededs(needed->next, list); 2275 2276 /* Process the current needed object. */ 2277 if (needed->obj != NULL) 2278 initlist_add_objects(needed->obj, needed->obj, list); 2279 } 2280 2281 /* 2282 * Scan all of the DAGs rooted in the range of objects from "obj" to 2283 * "tail" and add their init functions to "list". This recurses over 2284 * the DAGs and ensure the proper init ordering such that each object's 2285 * needed libraries are initialized before the object itself. At the 2286 * same time, this function adds the objects to the global finalization 2287 * list "list_fini" in the opposite order. The write lock must be 2288 * held when this function is called. 2289 */ 2290 static void 2291 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2292 { 2293 Obj_Entry *nobj; 2294 2295 if (obj->init_scanned || obj->init_done) 2296 return; 2297 obj->init_scanned = true; 2298 2299 /* Recursively process the successor objects. */ 2300 nobj = globallist_next(obj); 2301 if (nobj != NULL && obj != tail) 2302 initlist_add_objects(nobj, tail, list); 2303 2304 /* Recursively process the needed objects. */ 2305 if (obj->needed != NULL) 2306 initlist_add_neededs(obj->needed, list); 2307 if (obj->needed_filtees != NULL) 2308 initlist_add_neededs(obj->needed_filtees, list); 2309 if (obj->needed_aux_filtees != NULL) 2310 initlist_add_neededs(obj->needed_aux_filtees, list); 2311 2312 /* Add the object to the init list. */ 2313 objlist_push_tail(list, obj); 2314 2315 /* Add the object to the global fini list in the reverse order. */ 2316 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2317 && !obj->on_fini_list) { 2318 objlist_push_head(&list_fini, obj); 2319 obj->on_fini_list = true; 2320 } 2321 } 2322 2323 #ifndef FPTR_TARGET 2324 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2325 #endif 2326 2327 static void 2328 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2329 { 2330 Needed_Entry *needed, *needed1; 2331 2332 for (needed = n; needed != NULL; needed = needed->next) { 2333 if (needed->obj != NULL) { 2334 dlclose_locked(needed->obj, lockstate); 2335 needed->obj = NULL; 2336 } 2337 } 2338 for (needed = n; needed != NULL; needed = needed1) { 2339 needed1 = needed->next; 2340 free(needed); 2341 } 2342 } 2343 2344 static void 2345 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2346 { 2347 2348 free_needed_filtees(obj->needed_filtees, lockstate); 2349 obj->needed_filtees = NULL; 2350 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2351 obj->needed_aux_filtees = NULL; 2352 obj->filtees_loaded = false; 2353 } 2354 2355 static void 2356 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2357 RtldLockState *lockstate) 2358 { 2359 2360 for (; needed != NULL; needed = needed->next) { 2361 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2362 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2363 RTLD_LOCAL, lockstate); 2364 } 2365 } 2366 2367 static void 2368 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2369 { 2370 2371 lock_restart_for_upgrade(lockstate); 2372 if (!obj->filtees_loaded) { 2373 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2374 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2375 obj->filtees_loaded = true; 2376 } 2377 } 2378 2379 static int 2380 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2381 { 2382 Obj_Entry *obj1; 2383 2384 for (; needed != NULL; needed = needed->next) { 2385 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2386 flags & ~RTLD_LO_NOLOAD); 2387 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2388 return (-1); 2389 } 2390 return (0); 2391 } 2392 2393 /* 2394 * Given a shared object, traverse its list of needed objects, and load 2395 * each of them. Returns 0 on success. Generates an error message and 2396 * returns -1 on failure. 2397 */ 2398 static int 2399 load_needed_objects(Obj_Entry *first, int flags) 2400 { 2401 Obj_Entry *obj; 2402 2403 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2404 if (obj->marker) 2405 continue; 2406 if (process_needed(obj, obj->needed, flags) == -1) 2407 return (-1); 2408 } 2409 return (0); 2410 } 2411 2412 static int 2413 load_preload_objects(void) 2414 { 2415 char *p = ld_preload; 2416 Obj_Entry *obj; 2417 static const char delim[] = " \t:;"; 2418 2419 if (p == NULL) 2420 return 0; 2421 2422 p += strspn(p, delim); 2423 while (*p != '\0') { 2424 size_t len = strcspn(p, delim); 2425 char savech; 2426 2427 savech = p[len]; 2428 p[len] = '\0'; 2429 obj = load_object(p, -1, NULL, 0); 2430 if (obj == NULL) 2431 return -1; /* XXX - cleanup */ 2432 obj->z_interpose = true; 2433 p[len] = savech; 2434 p += len; 2435 p += strspn(p, delim); 2436 } 2437 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2438 return 0; 2439 } 2440 2441 static const char * 2442 printable_path(const char *path) 2443 { 2444 2445 return (path == NULL ? "<unknown>" : path); 2446 } 2447 2448 /* 2449 * Load a shared object into memory, if it is not already loaded. The 2450 * object may be specified by name or by user-supplied file descriptor 2451 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2452 * duplicate is. 2453 * 2454 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2455 * on failure. 2456 */ 2457 static Obj_Entry * 2458 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2459 { 2460 Obj_Entry *obj; 2461 int fd; 2462 struct stat sb; 2463 char *path; 2464 2465 fd = -1; 2466 if (name != NULL) { 2467 TAILQ_FOREACH(obj, &obj_list, next) { 2468 if (obj->marker || obj->doomed) 2469 continue; 2470 if (object_match_name(obj, name)) 2471 return (obj); 2472 } 2473 2474 path = find_library(name, refobj, &fd); 2475 if (path == NULL) 2476 return (NULL); 2477 } else 2478 path = NULL; 2479 2480 if (fd >= 0) { 2481 /* 2482 * search_library_pathfds() opens a fresh file descriptor for the 2483 * library, so there is no need to dup(). 2484 */ 2485 } else if (fd_u == -1) { 2486 /* 2487 * If we didn't find a match by pathname, or the name is not 2488 * supplied, open the file and check again by device and inode. 2489 * This avoids false mismatches caused by multiple links or ".." 2490 * in pathnames. 2491 * 2492 * To avoid a race, we open the file and use fstat() rather than 2493 * using stat(). 2494 */ 2495 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2496 _rtld_error("Cannot open \"%s\"", path); 2497 free(path); 2498 return (NULL); 2499 } 2500 } else { 2501 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2502 if (fd == -1) { 2503 _rtld_error("Cannot dup fd"); 2504 free(path); 2505 return (NULL); 2506 } 2507 } 2508 if (fstat(fd, &sb) == -1) { 2509 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2510 close(fd); 2511 free(path); 2512 return NULL; 2513 } 2514 TAILQ_FOREACH(obj, &obj_list, next) { 2515 if (obj->marker || obj->doomed) 2516 continue; 2517 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2518 break; 2519 } 2520 if (obj != NULL && name != NULL) { 2521 object_add_name(obj, name); 2522 free(path); 2523 close(fd); 2524 return obj; 2525 } 2526 if (flags & RTLD_LO_NOLOAD) { 2527 free(path); 2528 close(fd); 2529 return (NULL); 2530 } 2531 2532 /* First use of this object, so we must map it in */ 2533 obj = do_load_object(fd, name, path, &sb, flags); 2534 if (obj == NULL) 2535 free(path); 2536 close(fd); 2537 2538 return obj; 2539 } 2540 2541 static Obj_Entry * 2542 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2543 int flags) 2544 { 2545 Obj_Entry *obj; 2546 struct statfs fs; 2547 2548 /* 2549 * but first, make sure that environment variables haven't been 2550 * used to circumvent the noexec flag on a filesystem. 2551 */ 2552 if (dangerous_ld_env) { 2553 if (fstatfs(fd, &fs) != 0) { 2554 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2555 return NULL; 2556 } 2557 if (fs.f_flags & MNT_NOEXEC) { 2558 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2559 return NULL; 2560 } 2561 } 2562 dbg("loading \"%s\"", printable_path(path)); 2563 obj = map_object(fd, printable_path(path), sbp); 2564 if (obj == NULL) 2565 return NULL; 2566 2567 /* 2568 * If DT_SONAME is present in the object, digest_dynamic2 already 2569 * added it to the object names. 2570 */ 2571 if (name != NULL) 2572 object_add_name(obj, name); 2573 obj->path = path; 2574 if (!digest_dynamic(obj, 0)) 2575 goto errp; 2576 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2577 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2578 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2579 RTLD_LO_DLOPEN) { 2580 dbg("refusing to load non-loadable \"%s\"", obj->path); 2581 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2582 goto errp; 2583 } 2584 2585 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2586 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2587 obj_count++; 2588 obj_loads++; 2589 linkmap_add(obj); /* for GDB & dlinfo() */ 2590 max_stack_flags |= obj->stack_flags; 2591 2592 dbg(" %p .. %p: %s", obj->mapbase, 2593 obj->mapbase + obj->mapsize - 1, obj->path); 2594 if (obj->textrel) 2595 dbg(" WARNING: %s has impure text", obj->path); 2596 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2597 obj->path); 2598 2599 return (obj); 2600 2601 errp: 2602 munmap(obj->mapbase, obj->mapsize); 2603 obj_free(obj); 2604 return (NULL); 2605 } 2606 2607 static Obj_Entry * 2608 obj_from_addr(const void *addr) 2609 { 2610 Obj_Entry *obj; 2611 2612 TAILQ_FOREACH(obj, &obj_list, next) { 2613 if (obj->marker) 2614 continue; 2615 if (addr < (void *) obj->mapbase) 2616 continue; 2617 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2618 return obj; 2619 } 2620 return NULL; 2621 } 2622 2623 static void 2624 preinit_main(void) 2625 { 2626 Elf_Addr *preinit_addr; 2627 int index; 2628 2629 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2630 if (preinit_addr == NULL) 2631 return; 2632 2633 for (index = 0; index < obj_main->preinit_array_num; index++) { 2634 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2635 dbg("calling preinit function for %s at %p", obj_main->path, 2636 (void *)preinit_addr[index]); 2637 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2638 0, 0, obj_main->path); 2639 call_init_pointer(obj_main, preinit_addr[index]); 2640 } 2641 } 2642 } 2643 2644 /* 2645 * Call the finalization functions for each of the objects in "list" 2646 * belonging to the DAG of "root" and referenced once. If NULL "root" 2647 * is specified, every finalization function will be called regardless 2648 * of the reference count and the list elements won't be freed. All of 2649 * the objects are expected to have non-NULL fini functions. 2650 */ 2651 static void 2652 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2653 { 2654 Objlist_Entry *elm; 2655 char *saved_msg; 2656 Elf_Addr *fini_addr; 2657 int index; 2658 2659 assert(root == NULL || root->refcount == 1); 2660 2661 if (root != NULL) 2662 root->doomed = true; 2663 2664 /* 2665 * Preserve the current error message since a fini function might 2666 * call into the dynamic linker and overwrite it. 2667 */ 2668 saved_msg = errmsg_save(); 2669 do { 2670 STAILQ_FOREACH(elm, list, link) { 2671 if (root != NULL && (elm->obj->refcount != 1 || 2672 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2673 continue; 2674 /* Remove object from fini list to prevent recursive invocation. */ 2675 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2676 /* Ensure that new references cannot be acquired. */ 2677 elm->obj->doomed = true; 2678 2679 hold_object(elm->obj); 2680 lock_release(rtld_bind_lock, lockstate); 2681 /* 2682 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2683 * When this happens, DT_FINI_ARRAY is processed first. 2684 */ 2685 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2686 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2687 for (index = elm->obj->fini_array_num - 1; index >= 0; 2688 index--) { 2689 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2690 dbg("calling fini function for %s at %p", 2691 elm->obj->path, (void *)fini_addr[index]); 2692 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2693 (void *)fini_addr[index], 0, 0, elm->obj->path); 2694 call_initfini_pointer(elm->obj, fini_addr[index]); 2695 } 2696 } 2697 } 2698 if (elm->obj->fini != (Elf_Addr)NULL) { 2699 dbg("calling fini function for %s at %p", elm->obj->path, 2700 (void *)elm->obj->fini); 2701 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2702 0, 0, elm->obj->path); 2703 call_initfini_pointer(elm->obj, elm->obj->fini); 2704 } 2705 wlock_acquire(rtld_bind_lock, lockstate); 2706 unhold_object(elm->obj); 2707 /* No need to free anything if process is going down. */ 2708 if (root != NULL) 2709 free(elm); 2710 /* 2711 * We must restart the list traversal after every fini call 2712 * because a dlclose() call from the fini function or from 2713 * another thread might have modified the reference counts. 2714 */ 2715 break; 2716 } 2717 } while (elm != NULL); 2718 errmsg_restore(saved_msg); 2719 } 2720 2721 /* 2722 * Call the initialization functions for each of the objects in 2723 * "list". All of the objects are expected to have non-NULL init 2724 * functions. 2725 */ 2726 static void 2727 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2728 { 2729 Objlist_Entry *elm; 2730 Obj_Entry *obj; 2731 char *saved_msg; 2732 Elf_Addr *init_addr; 2733 void (*reg)(void (*)(void)); 2734 int index; 2735 2736 /* 2737 * Clean init_scanned flag so that objects can be rechecked and 2738 * possibly initialized earlier if any of vectors called below 2739 * cause the change by using dlopen. 2740 */ 2741 TAILQ_FOREACH(obj, &obj_list, next) { 2742 if (obj->marker) 2743 continue; 2744 obj->init_scanned = false; 2745 } 2746 2747 /* 2748 * Preserve the current error message since an init function might 2749 * call into the dynamic linker and overwrite it. 2750 */ 2751 saved_msg = errmsg_save(); 2752 STAILQ_FOREACH(elm, list, link) { 2753 if (elm->obj->init_done) /* Initialized early. */ 2754 continue; 2755 /* 2756 * Race: other thread might try to use this object before current 2757 * one completes the initialization. Not much can be done here 2758 * without better locking. 2759 */ 2760 elm->obj->init_done = true; 2761 hold_object(elm->obj); 2762 reg = NULL; 2763 if (elm->obj == obj_main && obj_main->crt_no_init) { 2764 reg = (void (*)(void (*)(void)))get_program_var_addr( 2765 "__libc_atexit", lockstate); 2766 } 2767 lock_release(rtld_bind_lock, lockstate); 2768 if (reg != NULL) { 2769 reg(rtld_exit); 2770 rtld_exit_ptr = rtld_nop_exit; 2771 } 2772 2773 /* 2774 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2775 * When this happens, DT_INIT is processed first. 2776 */ 2777 if (elm->obj->init != (Elf_Addr)NULL) { 2778 dbg("calling init function for %s at %p", elm->obj->path, 2779 (void *)elm->obj->init); 2780 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2781 0, 0, elm->obj->path); 2782 call_initfini_pointer(elm->obj, elm->obj->init); 2783 } 2784 init_addr = (Elf_Addr *)elm->obj->init_array; 2785 if (init_addr != NULL) { 2786 for (index = 0; index < elm->obj->init_array_num; index++) { 2787 if (init_addr[index] != 0 && init_addr[index] != 1) { 2788 dbg("calling init function for %s at %p", elm->obj->path, 2789 (void *)init_addr[index]); 2790 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2791 (void *)init_addr[index], 0, 0, elm->obj->path); 2792 call_init_pointer(elm->obj, init_addr[index]); 2793 } 2794 } 2795 } 2796 wlock_acquire(rtld_bind_lock, lockstate); 2797 unhold_object(elm->obj); 2798 } 2799 errmsg_restore(saved_msg); 2800 } 2801 2802 static void 2803 objlist_clear(Objlist *list) 2804 { 2805 Objlist_Entry *elm; 2806 2807 while (!STAILQ_EMPTY(list)) { 2808 elm = STAILQ_FIRST(list); 2809 STAILQ_REMOVE_HEAD(list, link); 2810 free(elm); 2811 } 2812 } 2813 2814 static Objlist_Entry * 2815 objlist_find(Objlist *list, const Obj_Entry *obj) 2816 { 2817 Objlist_Entry *elm; 2818 2819 STAILQ_FOREACH(elm, list, link) 2820 if (elm->obj == obj) 2821 return elm; 2822 return NULL; 2823 } 2824 2825 static void 2826 objlist_init(Objlist *list) 2827 { 2828 STAILQ_INIT(list); 2829 } 2830 2831 static void 2832 objlist_push_head(Objlist *list, Obj_Entry *obj) 2833 { 2834 Objlist_Entry *elm; 2835 2836 elm = NEW(Objlist_Entry); 2837 elm->obj = obj; 2838 STAILQ_INSERT_HEAD(list, elm, link); 2839 } 2840 2841 static void 2842 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2843 { 2844 Objlist_Entry *elm; 2845 2846 elm = NEW(Objlist_Entry); 2847 elm->obj = obj; 2848 STAILQ_INSERT_TAIL(list, elm, link); 2849 } 2850 2851 static void 2852 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2853 { 2854 Objlist_Entry *elm, *listelm; 2855 2856 STAILQ_FOREACH(listelm, list, link) { 2857 if (listelm->obj == listobj) 2858 break; 2859 } 2860 elm = NEW(Objlist_Entry); 2861 elm->obj = obj; 2862 if (listelm != NULL) 2863 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2864 else 2865 STAILQ_INSERT_TAIL(list, elm, link); 2866 } 2867 2868 static void 2869 objlist_remove(Objlist *list, Obj_Entry *obj) 2870 { 2871 Objlist_Entry *elm; 2872 2873 if ((elm = objlist_find(list, obj)) != NULL) { 2874 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2875 free(elm); 2876 } 2877 } 2878 2879 /* 2880 * Relocate dag rooted in the specified object. 2881 * Returns 0 on success, or -1 on failure. 2882 */ 2883 2884 static int 2885 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2886 int flags, RtldLockState *lockstate) 2887 { 2888 Objlist_Entry *elm; 2889 int error; 2890 2891 error = 0; 2892 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2893 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2894 lockstate); 2895 if (error == -1) 2896 break; 2897 } 2898 return (error); 2899 } 2900 2901 /* 2902 * Prepare for, or clean after, relocating an object marked with 2903 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2904 * segments are remapped read-write. After relocations are done, the 2905 * segment's permissions are returned back to the modes specified in 2906 * the phdrs. If any relocation happened, or always for wired 2907 * program, COW is triggered. 2908 */ 2909 static int 2910 reloc_textrel_prot(Obj_Entry *obj, bool before) 2911 { 2912 const Elf_Phdr *ph; 2913 void *base; 2914 size_t l, sz; 2915 int prot; 2916 2917 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2918 l--, ph++) { 2919 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2920 continue; 2921 base = obj->relocbase + trunc_page(ph->p_vaddr); 2922 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2923 trunc_page(ph->p_vaddr); 2924 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2925 if (mprotect(base, sz, prot) == -1) { 2926 _rtld_error("%s: Cannot write-%sable text segment: %s", 2927 obj->path, before ? "en" : "dis", 2928 rtld_strerror(errno)); 2929 return (-1); 2930 } 2931 } 2932 return (0); 2933 } 2934 2935 /* 2936 * Relocate single object. 2937 * Returns 0 on success, or -1 on failure. 2938 */ 2939 static int 2940 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2941 int flags, RtldLockState *lockstate) 2942 { 2943 2944 if (obj->relocated) 2945 return (0); 2946 obj->relocated = true; 2947 if (obj != rtldobj) 2948 dbg("relocating \"%s\"", obj->path); 2949 2950 if (obj->symtab == NULL || obj->strtab == NULL || 2951 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2952 _rtld_error("%s: Shared object has no run-time symbol table", 2953 obj->path); 2954 return (-1); 2955 } 2956 2957 /* There are relocations to the write-protected text segment. */ 2958 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2959 return (-1); 2960 2961 /* Process the non-PLT non-IFUNC relocations. */ 2962 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2963 return (-1); 2964 2965 /* Re-protected the text segment. */ 2966 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2967 return (-1); 2968 2969 /* Set the special PLT or GOT entries. */ 2970 init_pltgot(obj); 2971 2972 /* Process the PLT relocations. */ 2973 if (reloc_plt(obj, flags, lockstate) == -1) 2974 return (-1); 2975 /* Relocate the jump slots if we are doing immediate binding. */ 2976 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2977 lockstate) == -1) 2978 return (-1); 2979 2980 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2981 return (-1); 2982 2983 /* 2984 * Set up the magic number and version in the Obj_Entry. These 2985 * were checked in the crt1.o from the original ElfKit, so we 2986 * set them for backward compatibility. 2987 */ 2988 obj->magic = RTLD_MAGIC; 2989 obj->version = RTLD_VERSION; 2990 2991 return (0); 2992 } 2993 2994 /* 2995 * Relocate newly-loaded shared objects. The argument is a pointer to 2996 * the Obj_Entry for the first such object. All objects from the first 2997 * to the end of the list of objects are relocated. Returns 0 on success, 2998 * or -1 on failure. 2999 */ 3000 static int 3001 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3002 int flags, RtldLockState *lockstate) 3003 { 3004 Obj_Entry *obj; 3005 int error; 3006 3007 for (error = 0, obj = first; obj != NULL; 3008 obj = TAILQ_NEXT(obj, next)) { 3009 if (obj->marker) 3010 continue; 3011 error = relocate_object(obj, bind_now, rtldobj, flags, 3012 lockstate); 3013 if (error == -1) 3014 break; 3015 } 3016 return (error); 3017 } 3018 3019 /* 3020 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3021 * referencing STT_GNU_IFUNC symbols is postponed till the other 3022 * relocations are done. The indirect functions specified as 3023 * ifunc are allowed to call other symbols, so we need to have 3024 * objects relocated before asking for resolution from indirects. 3025 * 3026 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3027 * instead of the usual lazy handling of PLT slots. It is 3028 * consistent with how GNU does it. 3029 */ 3030 static int 3031 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3032 RtldLockState *lockstate) 3033 { 3034 3035 if (obj->ifuncs_resolved) 3036 return (0); 3037 obj->ifuncs_resolved = true; 3038 if (!obj->irelative && !obj->irelative_nonplt && 3039 !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3040 return (0); 3041 if (obj_disable_relro(obj) == -1 || 3042 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3043 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3044 lockstate) == -1) || 3045 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3046 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3047 obj_enforce_relro(obj) == -1) 3048 return (-1); 3049 return (0); 3050 } 3051 3052 static int 3053 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3054 RtldLockState *lockstate) 3055 { 3056 Objlist_Entry *elm; 3057 Obj_Entry *obj; 3058 3059 STAILQ_FOREACH(elm, list, link) { 3060 obj = elm->obj; 3061 if (obj->marker) 3062 continue; 3063 if (resolve_object_ifunc(obj, bind_now, flags, 3064 lockstate) == -1) 3065 return (-1); 3066 } 3067 return (0); 3068 } 3069 3070 /* 3071 * Cleanup procedure. It will be called (by the atexit mechanism) just 3072 * before the process exits. 3073 */ 3074 static void 3075 rtld_exit(void) 3076 { 3077 RtldLockState lockstate; 3078 3079 wlock_acquire(rtld_bind_lock, &lockstate); 3080 dbg("rtld_exit()"); 3081 objlist_call_fini(&list_fini, NULL, &lockstate); 3082 /* No need to remove the items from the list, since we are exiting. */ 3083 if (!libmap_disable) 3084 lm_fini(); 3085 lock_release(rtld_bind_lock, &lockstate); 3086 } 3087 3088 static void 3089 rtld_nop_exit(void) 3090 { 3091 } 3092 3093 /* 3094 * Iterate over a search path, translate each element, and invoke the 3095 * callback on the result. 3096 */ 3097 static void * 3098 path_enumerate(const char *path, path_enum_proc callback, 3099 const char *refobj_path, void *arg) 3100 { 3101 const char *trans; 3102 if (path == NULL) 3103 return (NULL); 3104 3105 path += strspn(path, ":;"); 3106 while (*path != '\0') { 3107 size_t len; 3108 char *res; 3109 3110 len = strcspn(path, ":;"); 3111 trans = lm_findn(refobj_path, path, len); 3112 if (trans) 3113 res = callback(trans, strlen(trans), arg); 3114 else 3115 res = callback(path, len, arg); 3116 3117 if (res != NULL) 3118 return (res); 3119 3120 path += len; 3121 path += strspn(path, ":;"); 3122 } 3123 3124 return (NULL); 3125 } 3126 3127 struct try_library_args { 3128 const char *name; 3129 size_t namelen; 3130 char *buffer; 3131 size_t buflen; 3132 int fd; 3133 }; 3134 3135 static void * 3136 try_library_path(const char *dir, size_t dirlen, void *param) 3137 { 3138 struct try_library_args *arg; 3139 int fd; 3140 3141 arg = param; 3142 if (*dir == '/' || trust) { 3143 char *pathname; 3144 3145 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3146 return (NULL); 3147 3148 pathname = arg->buffer; 3149 strncpy(pathname, dir, dirlen); 3150 pathname[dirlen] = '/'; 3151 strcpy(pathname + dirlen + 1, arg->name); 3152 3153 dbg(" Trying \"%s\"", pathname); 3154 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3155 if (fd >= 0) { 3156 dbg(" Opened \"%s\", fd %d", pathname, fd); 3157 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3158 strcpy(pathname, arg->buffer); 3159 arg->fd = fd; 3160 return (pathname); 3161 } else { 3162 dbg(" Failed to open \"%s\": %s", 3163 pathname, rtld_strerror(errno)); 3164 } 3165 } 3166 return (NULL); 3167 } 3168 3169 static char * 3170 search_library_path(const char *name, const char *path, 3171 const char *refobj_path, int *fdp) 3172 { 3173 char *p; 3174 struct try_library_args arg; 3175 3176 if (path == NULL) 3177 return NULL; 3178 3179 arg.name = name; 3180 arg.namelen = strlen(name); 3181 arg.buffer = xmalloc(PATH_MAX); 3182 arg.buflen = PATH_MAX; 3183 arg.fd = -1; 3184 3185 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3186 *fdp = arg.fd; 3187 3188 free(arg.buffer); 3189 3190 return (p); 3191 } 3192 3193 3194 /* 3195 * Finds the library with the given name using the directory descriptors 3196 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3197 * 3198 * Returns a freshly-opened close-on-exec file descriptor for the library, 3199 * or -1 if the library cannot be found. 3200 */ 3201 static char * 3202 search_library_pathfds(const char *name, const char *path, int *fdp) 3203 { 3204 char *envcopy, *fdstr, *found, *last_token; 3205 size_t len; 3206 int dirfd, fd; 3207 3208 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3209 3210 /* Don't load from user-specified libdirs into setuid binaries. */ 3211 if (!trust) 3212 return (NULL); 3213 3214 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3215 if (path == NULL) 3216 return (NULL); 3217 3218 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3219 if (name[0] == '/') { 3220 dbg("Absolute path (%s) passed to %s", name, __func__); 3221 return (NULL); 3222 } 3223 3224 /* 3225 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3226 * copy of the path, as strtok_r rewrites separator tokens 3227 * with '\0'. 3228 */ 3229 found = NULL; 3230 envcopy = xstrdup(path); 3231 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3232 fdstr = strtok_r(NULL, ":", &last_token)) { 3233 dirfd = parse_integer(fdstr); 3234 if (dirfd < 0) { 3235 _rtld_error("failed to parse directory FD: '%s'", 3236 fdstr); 3237 break; 3238 } 3239 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3240 if (fd >= 0) { 3241 *fdp = fd; 3242 len = strlen(fdstr) + strlen(name) + 3; 3243 found = xmalloc(len); 3244 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3245 _rtld_error("error generating '%d/%s'", 3246 dirfd, name); 3247 rtld_die(); 3248 } 3249 dbg("open('%s') => %d", found, fd); 3250 break; 3251 } 3252 } 3253 free(envcopy); 3254 3255 return (found); 3256 } 3257 3258 3259 int 3260 dlclose(void *handle) 3261 { 3262 RtldLockState lockstate; 3263 int error; 3264 3265 wlock_acquire(rtld_bind_lock, &lockstate); 3266 error = dlclose_locked(handle, &lockstate); 3267 lock_release(rtld_bind_lock, &lockstate); 3268 return (error); 3269 } 3270 3271 static int 3272 dlclose_locked(void *handle, RtldLockState *lockstate) 3273 { 3274 Obj_Entry *root; 3275 3276 root = dlcheck(handle); 3277 if (root == NULL) 3278 return -1; 3279 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3280 root->path); 3281 3282 /* Unreference the object and its dependencies. */ 3283 root->dl_refcount--; 3284 3285 if (root->refcount == 1) { 3286 /* 3287 * The object will be no longer referenced, so we must unload it. 3288 * First, call the fini functions. 3289 */ 3290 objlist_call_fini(&list_fini, root, lockstate); 3291 3292 unref_dag(root); 3293 3294 /* Finish cleaning up the newly-unreferenced objects. */ 3295 GDB_STATE(RT_DELETE,&root->linkmap); 3296 unload_object(root, lockstate); 3297 GDB_STATE(RT_CONSISTENT,NULL); 3298 } else 3299 unref_dag(root); 3300 3301 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3302 return 0; 3303 } 3304 3305 char * 3306 dlerror(void) 3307 { 3308 char *msg = error_message; 3309 error_message = NULL; 3310 return msg; 3311 } 3312 3313 /* 3314 * This function is deprecated and has no effect. 3315 */ 3316 void 3317 dllockinit(void *context, 3318 void *(*_lock_create)(void *context) __unused, 3319 void (*_rlock_acquire)(void *lock) __unused, 3320 void (*_wlock_acquire)(void *lock) __unused, 3321 void (*_lock_release)(void *lock) __unused, 3322 void (*_lock_destroy)(void *lock) __unused, 3323 void (*context_destroy)(void *context)) 3324 { 3325 static void *cur_context; 3326 static void (*cur_context_destroy)(void *); 3327 3328 /* Just destroy the context from the previous call, if necessary. */ 3329 if (cur_context_destroy != NULL) 3330 cur_context_destroy(cur_context); 3331 cur_context = context; 3332 cur_context_destroy = context_destroy; 3333 } 3334 3335 void * 3336 dlopen(const char *name, int mode) 3337 { 3338 3339 return (rtld_dlopen(name, -1, mode)); 3340 } 3341 3342 void * 3343 fdlopen(int fd, int mode) 3344 { 3345 3346 return (rtld_dlopen(NULL, fd, mode)); 3347 } 3348 3349 static void * 3350 rtld_dlopen(const char *name, int fd, int mode) 3351 { 3352 RtldLockState lockstate; 3353 int lo_flags; 3354 3355 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3356 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3357 if (ld_tracing != NULL) { 3358 rlock_acquire(rtld_bind_lock, &lockstate); 3359 if (sigsetjmp(lockstate.env, 0) != 0) 3360 lock_upgrade(rtld_bind_lock, &lockstate); 3361 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3362 lock_release(rtld_bind_lock, &lockstate); 3363 } 3364 lo_flags = RTLD_LO_DLOPEN; 3365 if (mode & RTLD_NODELETE) 3366 lo_flags |= RTLD_LO_NODELETE; 3367 if (mode & RTLD_NOLOAD) 3368 lo_flags |= RTLD_LO_NOLOAD; 3369 if (ld_tracing != NULL) 3370 lo_flags |= RTLD_LO_TRACE; 3371 3372 return (dlopen_object(name, fd, obj_main, lo_flags, 3373 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3374 } 3375 3376 static void 3377 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3378 { 3379 3380 obj->dl_refcount--; 3381 unref_dag(obj); 3382 if (obj->refcount == 0) 3383 unload_object(obj, lockstate); 3384 } 3385 3386 static Obj_Entry * 3387 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3388 int mode, RtldLockState *lockstate) 3389 { 3390 Obj_Entry *old_obj_tail; 3391 Obj_Entry *obj; 3392 Objlist initlist; 3393 RtldLockState mlockstate; 3394 int result; 3395 3396 objlist_init(&initlist); 3397 3398 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3399 wlock_acquire(rtld_bind_lock, &mlockstate); 3400 lockstate = &mlockstate; 3401 } 3402 GDB_STATE(RT_ADD,NULL); 3403 3404 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3405 obj = NULL; 3406 if (name == NULL && fd == -1) { 3407 obj = obj_main; 3408 obj->refcount++; 3409 } else { 3410 obj = load_object(name, fd, refobj, lo_flags); 3411 } 3412 3413 if (obj) { 3414 obj->dl_refcount++; 3415 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3416 objlist_push_tail(&list_global, obj); 3417 if (globallist_next(old_obj_tail) != NULL) { 3418 /* We loaded something new. */ 3419 assert(globallist_next(old_obj_tail) == obj); 3420 result = 0; 3421 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3422 !allocate_tls_offset(obj)) { 3423 _rtld_error("%s: No space available " 3424 "for static Thread Local Storage", obj->path); 3425 result = -1; 3426 } 3427 if (result != -1) 3428 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3429 RTLD_LO_EARLY)); 3430 init_dag(obj); 3431 ref_dag(obj); 3432 if (result != -1) 3433 result = rtld_verify_versions(&obj->dagmembers); 3434 if (result != -1 && ld_tracing) 3435 goto trace; 3436 if (result == -1 || relocate_object_dag(obj, 3437 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3438 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3439 lockstate) == -1) { 3440 dlopen_cleanup(obj, lockstate); 3441 obj = NULL; 3442 } else if (lo_flags & RTLD_LO_EARLY) { 3443 /* 3444 * Do not call the init functions for early loaded 3445 * filtees. The image is still not initialized enough 3446 * for them to work. 3447 * 3448 * Our object is found by the global object list and 3449 * will be ordered among all init calls done right 3450 * before transferring control to main. 3451 */ 3452 } else { 3453 /* Make list of init functions to call. */ 3454 initlist_add_objects(obj, obj, &initlist); 3455 } 3456 /* 3457 * Process all no_delete or global objects here, given 3458 * them own DAGs to prevent their dependencies from being 3459 * unloaded. This has to be done after we have loaded all 3460 * of the dependencies, so that we do not miss any. 3461 */ 3462 if (obj != NULL) 3463 process_z(obj); 3464 } else { 3465 /* 3466 * Bump the reference counts for objects on this DAG. If 3467 * this is the first dlopen() call for the object that was 3468 * already loaded as a dependency, initialize the dag 3469 * starting at it. 3470 */ 3471 init_dag(obj); 3472 ref_dag(obj); 3473 3474 if ((lo_flags & RTLD_LO_TRACE) != 0) 3475 goto trace; 3476 } 3477 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3478 obj->z_nodelete) && !obj->ref_nodel) { 3479 dbg("obj %s nodelete", obj->path); 3480 ref_dag(obj); 3481 obj->z_nodelete = obj->ref_nodel = true; 3482 } 3483 } 3484 3485 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3486 name); 3487 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3488 3489 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3490 map_stacks_exec(lockstate); 3491 if (obj != NULL) 3492 distribute_static_tls(&initlist, lockstate); 3493 } 3494 3495 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3496 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3497 lockstate) == -1) { 3498 objlist_clear(&initlist); 3499 dlopen_cleanup(obj, lockstate); 3500 if (lockstate == &mlockstate) 3501 lock_release(rtld_bind_lock, lockstate); 3502 return (NULL); 3503 } 3504 3505 if (!(lo_flags & RTLD_LO_EARLY)) { 3506 /* Call the init functions. */ 3507 objlist_call_init(&initlist, lockstate); 3508 } 3509 objlist_clear(&initlist); 3510 if (lockstate == &mlockstate) 3511 lock_release(rtld_bind_lock, lockstate); 3512 return obj; 3513 trace: 3514 trace_loaded_objects(obj); 3515 if (lockstate == &mlockstate) 3516 lock_release(rtld_bind_lock, lockstate); 3517 exit(0); 3518 } 3519 3520 static void * 3521 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3522 int flags) 3523 { 3524 DoneList donelist; 3525 const Obj_Entry *obj, *defobj; 3526 const Elf_Sym *def; 3527 SymLook req; 3528 RtldLockState lockstate; 3529 tls_index ti; 3530 void *sym; 3531 int res; 3532 3533 def = NULL; 3534 defobj = NULL; 3535 symlook_init(&req, name); 3536 req.ventry = ve; 3537 req.flags = flags | SYMLOOK_IN_PLT; 3538 req.lockstate = &lockstate; 3539 3540 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3541 rlock_acquire(rtld_bind_lock, &lockstate); 3542 if (sigsetjmp(lockstate.env, 0) != 0) 3543 lock_upgrade(rtld_bind_lock, &lockstate); 3544 if (handle == NULL || handle == RTLD_NEXT || 3545 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3546 3547 if ((obj = obj_from_addr(retaddr)) == NULL) { 3548 _rtld_error("Cannot determine caller's shared object"); 3549 lock_release(rtld_bind_lock, &lockstate); 3550 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3551 return NULL; 3552 } 3553 if (handle == NULL) { /* Just the caller's shared object. */ 3554 res = symlook_obj(&req, obj); 3555 if (res == 0) { 3556 def = req.sym_out; 3557 defobj = req.defobj_out; 3558 } 3559 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3560 handle == RTLD_SELF) { /* ... caller included */ 3561 if (handle == RTLD_NEXT) 3562 obj = globallist_next(obj); 3563 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3564 if (obj->marker) 3565 continue; 3566 res = symlook_obj(&req, obj); 3567 if (res == 0) { 3568 if (def == NULL || 3569 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3570 def = req.sym_out; 3571 defobj = req.defobj_out; 3572 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3573 break; 3574 } 3575 } 3576 } 3577 /* 3578 * Search the dynamic linker itself, and possibly resolve the 3579 * symbol from there. This is how the application links to 3580 * dynamic linker services such as dlopen. 3581 */ 3582 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3583 res = symlook_obj(&req, &obj_rtld); 3584 if (res == 0) { 3585 def = req.sym_out; 3586 defobj = req.defobj_out; 3587 } 3588 } 3589 } else { 3590 assert(handle == RTLD_DEFAULT); 3591 res = symlook_default(&req, obj); 3592 if (res == 0) { 3593 defobj = req.defobj_out; 3594 def = req.sym_out; 3595 } 3596 } 3597 } else { 3598 if ((obj = dlcheck(handle)) == NULL) { 3599 lock_release(rtld_bind_lock, &lockstate); 3600 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3601 return NULL; 3602 } 3603 3604 donelist_init(&donelist); 3605 if (obj->mainprog) { 3606 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3607 res = symlook_global(&req, &donelist); 3608 if (res == 0) { 3609 def = req.sym_out; 3610 defobj = req.defobj_out; 3611 } 3612 /* 3613 * Search the dynamic linker itself, and possibly resolve the 3614 * symbol from there. This is how the application links to 3615 * dynamic linker services such as dlopen. 3616 */ 3617 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3618 res = symlook_obj(&req, &obj_rtld); 3619 if (res == 0) { 3620 def = req.sym_out; 3621 defobj = req.defobj_out; 3622 } 3623 } 3624 } 3625 else { 3626 /* Search the whole DAG rooted at the given object. */ 3627 res = symlook_list(&req, &obj->dagmembers, &donelist); 3628 if (res == 0) { 3629 def = req.sym_out; 3630 defobj = req.defobj_out; 3631 } 3632 } 3633 } 3634 3635 if (def != NULL) { 3636 lock_release(rtld_bind_lock, &lockstate); 3637 3638 /* 3639 * The value required by the caller is derived from the value 3640 * of the symbol. this is simply the relocated value of the 3641 * symbol. 3642 */ 3643 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3644 sym = make_function_pointer(def, defobj); 3645 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3646 sym = rtld_resolve_ifunc(defobj, def); 3647 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3648 ti.ti_module = defobj->tlsindex; 3649 ti.ti_offset = def->st_value; 3650 sym = __tls_get_addr(&ti); 3651 } else 3652 sym = defobj->relocbase + def->st_value; 3653 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3654 return (sym); 3655 } 3656 3657 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3658 ve != NULL ? ve->name : ""); 3659 lock_release(rtld_bind_lock, &lockstate); 3660 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3661 return NULL; 3662 } 3663 3664 void * 3665 dlsym(void *handle, const char *name) 3666 { 3667 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3668 SYMLOOK_DLSYM); 3669 } 3670 3671 dlfunc_t 3672 dlfunc(void *handle, const char *name) 3673 { 3674 union { 3675 void *d; 3676 dlfunc_t f; 3677 } rv; 3678 3679 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3680 SYMLOOK_DLSYM); 3681 return (rv.f); 3682 } 3683 3684 void * 3685 dlvsym(void *handle, const char *name, const char *version) 3686 { 3687 Ver_Entry ventry; 3688 3689 ventry.name = version; 3690 ventry.file = NULL; 3691 ventry.hash = elf_hash(version); 3692 ventry.flags= 0; 3693 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3694 SYMLOOK_DLSYM); 3695 } 3696 3697 int 3698 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3699 { 3700 const Obj_Entry *obj; 3701 RtldLockState lockstate; 3702 3703 rlock_acquire(rtld_bind_lock, &lockstate); 3704 obj = obj_from_addr(addr); 3705 if (obj == NULL) { 3706 _rtld_error("No shared object contains address"); 3707 lock_release(rtld_bind_lock, &lockstate); 3708 return (0); 3709 } 3710 rtld_fill_dl_phdr_info(obj, phdr_info); 3711 lock_release(rtld_bind_lock, &lockstate); 3712 return (1); 3713 } 3714 3715 int 3716 dladdr(const void *addr, Dl_info *info) 3717 { 3718 const Obj_Entry *obj; 3719 const Elf_Sym *def; 3720 void *symbol_addr; 3721 unsigned long symoffset; 3722 RtldLockState lockstate; 3723 3724 rlock_acquire(rtld_bind_lock, &lockstate); 3725 obj = obj_from_addr(addr); 3726 if (obj == NULL) { 3727 _rtld_error("No shared object contains address"); 3728 lock_release(rtld_bind_lock, &lockstate); 3729 return 0; 3730 } 3731 info->dli_fname = obj->path; 3732 info->dli_fbase = obj->mapbase; 3733 info->dli_saddr = (void *)0; 3734 info->dli_sname = NULL; 3735 3736 /* 3737 * Walk the symbol list looking for the symbol whose address is 3738 * closest to the address sent in. 3739 */ 3740 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3741 def = obj->symtab + symoffset; 3742 3743 /* 3744 * For skip the symbol if st_shndx is either SHN_UNDEF or 3745 * SHN_COMMON. 3746 */ 3747 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3748 continue; 3749 3750 /* 3751 * If the symbol is greater than the specified address, or if it 3752 * is further away from addr than the current nearest symbol, 3753 * then reject it. 3754 */ 3755 symbol_addr = obj->relocbase + def->st_value; 3756 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3757 continue; 3758 3759 /* Update our idea of the nearest symbol. */ 3760 info->dli_sname = obj->strtab + def->st_name; 3761 info->dli_saddr = symbol_addr; 3762 3763 /* Exact match? */ 3764 if (info->dli_saddr == addr) 3765 break; 3766 } 3767 lock_release(rtld_bind_lock, &lockstate); 3768 return 1; 3769 } 3770 3771 int 3772 dlinfo(void *handle, int request, void *p) 3773 { 3774 const Obj_Entry *obj; 3775 RtldLockState lockstate; 3776 int error; 3777 3778 rlock_acquire(rtld_bind_lock, &lockstate); 3779 3780 if (handle == NULL || handle == RTLD_SELF) { 3781 void *retaddr; 3782 3783 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3784 if ((obj = obj_from_addr(retaddr)) == NULL) 3785 _rtld_error("Cannot determine caller's shared object"); 3786 } else 3787 obj = dlcheck(handle); 3788 3789 if (obj == NULL) { 3790 lock_release(rtld_bind_lock, &lockstate); 3791 return (-1); 3792 } 3793 3794 error = 0; 3795 switch (request) { 3796 case RTLD_DI_LINKMAP: 3797 *((struct link_map const **)p) = &obj->linkmap; 3798 break; 3799 case RTLD_DI_ORIGIN: 3800 error = rtld_dirname(obj->path, p); 3801 break; 3802 3803 case RTLD_DI_SERINFOSIZE: 3804 case RTLD_DI_SERINFO: 3805 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3806 break; 3807 3808 default: 3809 _rtld_error("Invalid request %d passed to dlinfo()", request); 3810 error = -1; 3811 } 3812 3813 lock_release(rtld_bind_lock, &lockstate); 3814 3815 return (error); 3816 } 3817 3818 static void 3819 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3820 { 3821 3822 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3823 phdr_info->dlpi_name = obj->path; 3824 phdr_info->dlpi_phdr = obj->phdr; 3825 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3826 phdr_info->dlpi_tls_modid = obj->tlsindex; 3827 phdr_info->dlpi_tls_data = obj->tlsinit; 3828 phdr_info->dlpi_adds = obj_loads; 3829 phdr_info->dlpi_subs = obj_loads - obj_count; 3830 } 3831 3832 int 3833 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3834 { 3835 struct dl_phdr_info phdr_info; 3836 Obj_Entry *obj, marker; 3837 RtldLockState bind_lockstate, phdr_lockstate; 3838 int error; 3839 3840 init_marker(&marker); 3841 error = 0; 3842 3843 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3844 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3845 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3846 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3847 rtld_fill_dl_phdr_info(obj, &phdr_info); 3848 hold_object(obj); 3849 lock_release(rtld_bind_lock, &bind_lockstate); 3850 3851 error = callback(&phdr_info, sizeof phdr_info, param); 3852 3853 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3854 unhold_object(obj); 3855 obj = globallist_next(&marker); 3856 TAILQ_REMOVE(&obj_list, &marker, next); 3857 if (error != 0) { 3858 lock_release(rtld_bind_lock, &bind_lockstate); 3859 lock_release(rtld_phdr_lock, &phdr_lockstate); 3860 return (error); 3861 } 3862 } 3863 3864 if (error == 0) { 3865 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3866 lock_release(rtld_bind_lock, &bind_lockstate); 3867 error = callback(&phdr_info, sizeof(phdr_info), param); 3868 } 3869 lock_release(rtld_phdr_lock, &phdr_lockstate); 3870 return (error); 3871 } 3872 3873 static void * 3874 fill_search_info(const char *dir, size_t dirlen, void *param) 3875 { 3876 struct fill_search_info_args *arg; 3877 3878 arg = param; 3879 3880 if (arg->request == RTLD_DI_SERINFOSIZE) { 3881 arg->serinfo->dls_cnt ++; 3882 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3883 } else { 3884 struct dl_serpath *s_entry; 3885 3886 s_entry = arg->serpath; 3887 s_entry->dls_name = arg->strspace; 3888 s_entry->dls_flags = arg->flags; 3889 3890 strncpy(arg->strspace, dir, dirlen); 3891 arg->strspace[dirlen] = '\0'; 3892 3893 arg->strspace += dirlen + 1; 3894 arg->serpath++; 3895 } 3896 3897 return (NULL); 3898 } 3899 3900 static int 3901 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3902 { 3903 struct dl_serinfo _info; 3904 struct fill_search_info_args args; 3905 3906 args.request = RTLD_DI_SERINFOSIZE; 3907 args.serinfo = &_info; 3908 3909 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3910 _info.dls_cnt = 0; 3911 3912 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3913 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3914 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3915 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3916 if (!obj->z_nodeflib) 3917 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3918 3919 3920 if (request == RTLD_DI_SERINFOSIZE) { 3921 info->dls_size = _info.dls_size; 3922 info->dls_cnt = _info.dls_cnt; 3923 return (0); 3924 } 3925 3926 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3927 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3928 return (-1); 3929 } 3930 3931 args.request = RTLD_DI_SERINFO; 3932 args.serinfo = info; 3933 args.serpath = &info->dls_serpath[0]; 3934 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3935 3936 args.flags = LA_SER_RUNPATH; 3937 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3938 return (-1); 3939 3940 args.flags = LA_SER_LIBPATH; 3941 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3942 return (-1); 3943 3944 args.flags = LA_SER_RUNPATH; 3945 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3946 return (-1); 3947 3948 args.flags = LA_SER_CONFIG; 3949 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3950 != NULL) 3951 return (-1); 3952 3953 args.flags = LA_SER_DEFAULT; 3954 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3955 fill_search_info, NULL, &args) != NULL) 3956 return (-1); 3957 return (0); 3958 } 3959 3960 static int 3961 rtld_dirname(const char *path, char *bname) 3962 { 3963 const char *endp; 3964 3965 /* Empty or NULL string gets treated as "." */ 3966 if (path == NULL || *path == '\0') { 3967 bname[0] = '.'; 3968 bname[1] = '\0'; 3969 return (0); 3970 } 3971 3972 /* Strip trailing slashes */ 3973 endp = path + strlen(path) - 1; 3974 while (endp > path && *endp == '/') 3975 endp--; 3976 3977 /* Find the start of the dir */ 3978 while (endp > path && *endp != '/') 3979 endp--; 3980 3981 /* Either the dir is "/" or there are no slashes */ 3982 if (endp == path) { 3983 bname[0] = *endp == '/' ? '/' : '.'; 3984 bname[1] = '\0'; 3985 return (0); 3986 } else { 3987 do { 3988 endp--; 3989 } while (endp > path && *endp == '/'); 3990 } 3991 3992 if (endp - path + 2 > PATH_MAX) 3993 { 3994 _rtld_error("Filename is too long: %s", path); 3995 return(-1); 3996 } 3997 3998 strncpy(bname, path, endp - path + 1); 3999 bname[endp - path + 1] = '\0'; 4000 return (0); 4001 } 4002 4003 static int 4004 rtld_dirname_abs(const char *path, char *base) 4005 { 4006 char *last; 4007 4008 if (realpath(path, base) == NULL) { 4009 _rtld_error("realpath \"%s\" failed (%s)", path, 4010 rtld_strerror(errno)); 4011 return (-1); 4012 } 4013 dbg("%s -> %s", path, base); 4014 last = strrchr(base, '/'); 4015 if (last == NULL) { 4016 _rtld_error("non-abs result from realpath \"%s\"", path); 4017 return (-1); 4018 } 4019 if (last != base) 4020 *last = '\0'; 4021 return (0); 4022 } 4023 4024 static void 4025 linkmap_add(Obj_Entry *obj) 4026 { 4027 struct link_map *l = &obj->linkmap; 4028 struct link_map *prev; 4029 4030 obj->linkmap.l_name = obj->path; 4031 obj->linkmap.l_addr = obj->mapbase; 4032 obj->linkmap.l_ld = obj->dynamic; 4033 #ifdef __mips__ 4034 /* GDB needs load offset on MIPS to use the symbols */ 4035 obj->linkmap.l_offs = obj->relocbase; 4036 #endif 4037 4038 if (r_debug.r_map == NULL) { 4039 r_debug.r_map = l; 4040 return; 4041 } 4042 4043 /* 4044 * Scan to the end of the list, but not past the entry for the 4045 * dynamic linker, which we want to keep at the very end. 4046 */ 4047 for (prev = r_debug.r_map; 4048 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4049 prev = prev->l_next) 4050 ; 4051 4052 /* Link in the new entry. */ 4053 l->l_prev = prev; 4054 l->l_next = prev->l_next; 4055 if (l->l_next != NULL) 4056 l->l_next->l_prev = l; 4057 prev->l_next = l; 4058 } 4059 4060 static void 4061 linkmap_delete(Obj_Entry *obj) 4062 { 4063 struct link_map *l = &obj->linkmap; 4064 4065 if (l->l_prev == NULL) { 4066 if ((r_debug.r_map = l->l_next) != NULL) 4067 l->l_next->l_prev = NULL; 4068 return; 4069 } 4070 4071 if ((l->l_prev->l_next = l->l_next) != NULL) 4072 l->l_next->l_prev = l->l_prev; 4073 } 4074 4075 /* 4076 * Function for the debugger to set a breakpoint on to gain control. 4077 * 4078 * The two parameters allow the debugger to easily find and determine 4079 * what the runtime loader is doing and to whom it is doing it. 4080 * 4081 * When the loadhook trap is hit (r_debug_state, set at program 4082 * initialization), the arguments can be found on the stack: 4083 * 4084 * +8 struct link_map *m 4085 * +4 struct r_debug *rd 4086 * +0 RetAddr 4087 */ 4088 void 4089 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4090 { 4091 /* 4092 * The following is a hack to force the compiler to emit calls to 4093 * this function, even when optimizing. If the function is empty, 4094 * the compiler is not obliged to emit any code for calls to it, 4095 * even when marked __noinline. However, gdb depends on those 4096 * calls being made. 4097 */ 4098 __compiler_membar(); 4099 } 4100 4101 /* 4102 * A function called after init routines have completed. This can be used to 4103 * break before a program's entry routine is called, and can be used when 4104 * main is not available in the symbol table. 4105 */ 4106 void 4107 _r_debug_postinit(struct link_map *m __unused) 4108 { 4109 4110 /* See r_debug_state(). */ 4111 __compiler_membar(); 4112 } 4113 4114 static void 4115 release_object(Obj_Entry *obj) 4116 { 4117 4118 if (obj->holdcount > 0) { 4119 obj->unholdfree = true; 4120 return; 4121 } 4122 munmap(obj->mapbase, obj->mapsize); 4123 linkmap_delete(obj); 4124 obj_free(obj); 4125 } 4126 4127 /* 4128 * Get address of the pointer variable in the main program. 4129 * Prefer non-weak symbol over the weak one. 4130 */ 4131 static const void ** 4132 get_program_var_addr(const char *name, RtldLockState *lockstate) 4133 { 4134 SymLook req; 4135 DoneList donelist; 4136 4137 symlook_init(&req, name); 4138 req.lockstate = lockstate; 4139 donelist_init(&donelist); 4140 if (symlook_global(&req, &donelist) != 0) 4141 return (NULL); 4142 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4143 return ((const void **)make_function_pointer(req.sym_out, 4144 req.defobj_out)); 4145 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4146 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4147 else 4148 return ((const void **)(req.defobj_out->relocbase + 4149 req.sym_out->st_value)); 4150 } 4151 4152 /* 4153 * Set a pointer variable in the main program to the given value. This 4154 * is used to set key variables such as "environ" before any of the 4155 * init functions are called. 4156 */ 4157 static void 4158 set_program_var(const char *name, const void *value) 4159 { 4160 const void **addr; 4161 4162 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4163 dbg("\"%s\": *%p <-- %p", name, addr, value); 4164 *addr = value; 4165 } 4166 } 4167 4168 /* 4169 * Search the global objects, including dependencies and main object, 4170 * for the given symbol. 4171 */ 4172 static int 4173 symlook_global(SymLook *req, DoneList *donelist) 4174 { 4175 SymLook req1; 4176 const Objlist_Entry *elm; 4177 int res; 4178 4179 symlook_init_from_req(&req1, req); 4180 4181 /* Search all objects loaded at program start up. */ 4182 if (req->defobj_out == NULL || 4183 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4184 res = symlook_list(&req1, &list_main, donelist); 4185 if (res == 0 && (req->defobj_out == NULL || 4186 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4187 req->sym_out = req1.sym_out; 4188 req->defobj_out = req1.defobj_out; 4189 assert(req->defobj_out != NULL); 4190 } 4191 } 4192 4193 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4194 STAILQ_FOREACH(elm, &list_global, link) { 4195 if (req->defobj_out != NULL && 4196 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4197 break; 4198 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4199 if (res == 0 && (req->defobj_out == NULL || 4200 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4201 req->sym_out = req1.sym_out; 4202 req->defobj_out = req1.defobj_out; 4203 assert(req->defobj_out != NULL); 4204 } 4205 } 4206 4207 return (req->sym_out != NULL ? 0 : ESRCH); 4208 } 4209 4210 /* 4211 * Given a symbol name in a referencing object, find the corresponding 4212 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4213 * no definition was found. Returns a pointer to the Obj_Entry of the 4214 * defining object via the reference parameter DEFOBJ_OUT. 4215 */ 4216 static int 4217 symlook_default(SymLook *req, const Obj_Entry *refobj) 4218 { 4219 DoneList donelist; 4220 const Objlist_Entry *elm; 4221 SymLook req1; 4222 int res; 4223 4224 donelist_init(&donelist); 4225 symlook_init_from_req(&req1, req); 4226 4227 /* 4228 * Look first in the referencing object if linked symbolically, 4229 * and similarly handle protected symbols. 4230 */ 4231 res = symlook_obj(&req1, refobj); 4232 if (res == 0 && (refobj->symbolic || 4233 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4234 req->sym_out = req1.sym_out; 4235 req->defobj_out = req1.defobj_out; 4236 assert(req->defobj_out != NULL); 4237 } 4238 if (refobj->symbolic || req->defobj_out != NULL) 4239 donelist_check(&donelist, refobj); 4240 4241 symlook_global(req, &donelist); 4242 4243 /* Search all dlopened DAGs containing the referencing object. */ 4244 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4245 if (req->sym_out != NULL && 4246 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4247 break; 4248 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4249 if (res == 0 && (req->sym_out == NULL || 4250 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4251 req->sym_out = req1.sym_out; 4252 req->defobj_out = req1.defobj_out; 4253 assert(req->defobj_out != NULL); 4254 } 4255 } 4256 4257 /* 4258 * Search the dynamic linker itself, and possibly resolve the 4259 * symbol from there. This is how the application links to 4260 * dynamic linker services such as dlopen. 4261 */ 4262 if (req->sym_out == NULL || 4263 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4264 res = symlook_obj(&req1, &obj_rtld); 4265 if (res == 0) { 4266 req->sym_out = req1.sym_out; 4267 req->defobj_out = req1.defobj_out; 4268 assert(req->defobj_out != NULL); 4269 } 4270 } 4271 4272 return (req->sym_out != NULL ? 0 : ESRCH); 4273 } 4274 4275 static int 4276 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4277 { 4278 const Elf_Sym *def; 4279 const Obj_Entry *defobj; 4280 const Objlist_Entry *elm; 4281 SymLook req1; 4282 int res; 4283 4284 def = NULL; 4285 defobj = NULL; 4286 STAILQ_FOREACH(elm, objlist, link) { 4287 if (donelist_check(dlp, elm->obj)) 4288 continue; 4289 symlook_init_from_req(&req1, req); 4290 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4291 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4292 def = req1.sym_out; 4293 defobj = req1.defobj_out; 4294 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4295 break; 4296 } 4297 } 4298 } 4299 if (def != NULL) { 4300 req->sym_out = def; 4301 req->defobj_out = defobj; 4302 return (0); 4303 } 4304 return (ESRCH); 4305 } 4306 4307 /* 4308 * Search the chain of DAGS cointed to by the given Needed_Entry 4309 * for a symbol of the given name. Each DAG is scanned completely 4310 * before advancing to the next one. Returns a pointer to the symbol, 4311 * or NULL if no definition was found. 4312 */ 4313 static int 4314 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4315 { 4316 const Elf_Sym *def; 4317 const Needed_Entry *n; 4318 const Obj_Entry *defobj; 4319 SymLook req1; 4320 int res; 4321 4322 def = NULL; 4323 defobj = NULL; 4324 symlook_init_from_req(&req1, req); 4325 for (n = needed; n != NULL; n = n->next) { 4326 if (n->obj == NULL || 4327 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4328 continue; 4329 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4330 def = req1.sym_out; 4331 defobj = req1.defobj_out; 4332 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4333 break; 4334 } 4335 } 4336 if (def != NULL) { 4337 req->sym_out = def; 4338 req->defobj_out = defobj; 4339 return (0); 4340 } 4341 return (ESRCH); 4342 } 4343 4344 /* 4345 * Search the symbol table of a single shared object for a symbol of 4346 * the given name and version, if requested. Returns a pointer to the 4347 * symbol, or NULL if no definition was found. If the object is 4348 * filter, return filtered symbol from filtee. 4349 * 4350 * The symbol's hash value is passed in for efficiency reasons; that 4351 * eliminates many recomputations of the hash value. 4352 */ 4353 int 4354 symlook_obj(SymLook *req, const Obj_Entry *obj) 4355 { 4356 DoneList donelist; 4357 SymLook req1; 4358 int flags, res, mres; 4359 4360 /* 4361 * If there is at least one valid hash at this point, we prefer to 4362 * use the faster GNU version if available. 4363 */ 4364 if (obj->valid_hash_gnu) 4365 mres = symlook_obj1_gnu(req, obj); 4366 else if (obj->valid_hash_sysv) 4367 mres = symlook_obj1_sysv(req, obj); 4368 else 4369 return (EINVAL); 4370 4371 if (mres == 0) { 4372 if (obj->needed_filtees != NULL) { 4373 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4374 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4375 donelist_init(&donelist); 4376 symlook_init_from_req(&req1, req); 4377 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4378 if (res == 0) { 4379 req->sym_out = req1.sym_out; 4380 req->defobj_out = req1.defobj_out; 4381 } 4382 return (res); 4383 } 4384 if (obj->needed_aux_filtees != NULL) { 4385 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4386 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4387 donelist_init(&donelist); 4388 symlook_init_from_req(&req1, req); 4389 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4390 if (res == 0) { 4391 req->sym_out = req1.sym_out; 4392 req->defobj_out = req1.defobj_out; 4393 return (res); 4394 } 4395 } 4396 } 4397 return (mres); 4398 } 4399 4400 /* Symbol match routine common to both hash functions */ 4401 static bool 4402 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4403 const unsigned long symnum) 4404 { 4405 Elf_Versym verndx; 4406 const Elf_Sym *symp; 4407 const char *strp; 4408 4409 symp = obj->symtab + symnum; 4410 strp = obj->strtab + symp->st_name; 4411 4412 switch (ELF_ST_TYPE(symp->st_info)) { 4413 case STT_FUNC: 4414 case STT_NOTYPE: 4415 case STT_OBJECT: 4416 case STT_COMMON: 4417 case STT_GNU_IFUNC: 4418 if (symp->st_value == 0) 4419 return (false); 4420 /* fallthrough */ 4421 case STT_TLS: 4422 if (symp->st_shndx != SHN_UNDEF) 4423 break; 4424 #ifndef __mips__ 4425 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4426 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4427 break; 4428 #endif 4429 /* fallthrough */ 4430 default: 4431 return (false); 4432 } 4433 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4434 return (false); 4435 4436 if (req->ventry == NULL) { 4437 if (obj->versyms != NULL) { 4438 verndx = VER_NDX(obj->versyms[symnum]); 4439 if (verndx > obj->vernum) { 4440 _rtld_error( 4441 "%s: symbol %s references wrong version %d", 4442 obj->path, obj->strtab + symnum, verndx); 4443 return (false); 4444 } 4445 /* 4446 * If we are not called from dlsym (i.e. this 4447 * is a normal relocation from unversioned 4448 * binary), accept the symbol immediately if 4449 * it happens to have first version after this 4450 * shared object became versioned. Otherwise, 4451 * if symbol is versioned and not hidden, 4452 * remember it. If it is the only symbol with 4453 * this name exported by the shared object, it 4454 * will be returned as a match by the calling 4455 * function. If symbol is global (verndx < 2) 4456 * accept it unconditionally. 4457 */ 4458 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4459 verndx == VER_NDX_GIVEN) { 4460 result->sym_out = symp; 4461 return (true); 4462 } 4463 else if (verndx >= VER_NDX_GIVEN) { 4464 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4465 == 0) { 4466 if (result->vsymp == NULL) 4467 result->vsymp = symp; 4468 result->vcount++; 4469 } 4470 return (false); 4471 } 4472 } 4473 result->sym_out = symp; 4474 return (true); 4475 } 4476 if (obj->versyms == NULL) { 4477 if (object_match_name(obj, req->ventry->name)) { 4478 _rtld_error("%s: object %s should provide version %s " 4479 "for symbol %s", obj_rtld.path, obj->path, 4480 req->ventry->name, obj->strtab + symnum); 4481 return (false); 4482 } 4483 } else { 4484 verndx = VER_NDX(obj->versyms[symnum]); 4485 if (verndx > obj->vernum) { 4486 _rtld_error("%s: symbol %s references wrong version %d", 4487 obj->path, obj->strtab + symnum, verndx); 4488 return (false); 4489 } 4490 if (obj->vertab[verndx].hash != req->ventry->hash || 4491 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4492 /* 4493 * Version does not match. Look if this is a 4494 * global symbol and if it is not hidden. If 4495 * global symbol (verndx < 2) is available, 4496 * use it. Do not return symbol if we are 4497 * called by dlvsym, because dlvsym looks for 4498 * a specific version and default one is not 4499 * what dlvsym wants. 4500 */ 4501 if ((req->flags & SYMLOOK_DLSYM) || 4502 (verndx >= VER_NDX_GIVEN) || 4503 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4504 return (false); 4505 } 4506 } 4507 result->sym_out = symp; 4508 return (true); 4509 } 4510 4511 /* 4512 * Search for symbol using SysV hash function. 4513 * obj->buckets is known not to be NULL at this point; the test for this was 4514 * performed with the obj->valid_hash_sysv assignment. 4515 */ 4516 static int 4517 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4518 { 4519 unsigned long symnum; 4520 Sym_Match_Result matchres; 4521 4522 matchres.sym_out = NULL; 4523 matchres.vsymp = NULL; 4524 matchres.vcount = 0; 4525 4526 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4527 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4528 if (symnum >= obj->nchains) 4529 return (ESRCH); /* Bad object */ 4530 4531 if (matched_symbol(req, obj, &matchres, symnum)) { 4532 req->sym_out = matchres.sym_out; 4533 req->defobj_out = obj; 4534 return (0); 4535 } 4536 } 4537 if (matchres.vcount == 1) { 4538 req->sym_out = matchres.vsymp; 4539 req->defobj_out = obj; 4540 return (0); 4541 } 4542 return (ESRCH); 4543 } 4544 4545 /* Search for symbol using GNU hash function */ 4546 static int 4547 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4548 { 4549 Elf_Addr bloom_word; 4550 const Elf32_Word *hashval; 4551 Elf32_Word bucket; 4552 Sym_Match_Result matchres; 4553 unsigned int h1, h2; 4554 unsigned long symnum; 4555 4556 matchres.sym_out = NULL; 4557 matchres.vsymp = NULL; 4558 matchres.vcount = 0; 4559 4560 /* Pick right bitmask word from Bloom filter array */ 4561 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4562 obj->maskwords_bm_gnu]; 4563 4564 /* Calculate modulus word size of gnu hash and its derivative */ 4565 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4566 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4567 4568 /* Filter out the "definitely not in set" queries */ 4569 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4570 return (ESRCH); 4571 4572 /* Locate hash chain and corresponding value element*/ 4573 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4574 if (bucket == 0) 4575 return (ESRCH); 4576 hashval = &obj->chain_zero_gnu[bucket]; 4577 do { 4578 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4579 symnum = hashval - obj->chain_zero_gnu; 4580 if (matched_symbol(req, obj, &matchres, symnum)) { 4581 req->sym_out = matchres.sym_out; 4582 req->defobj_out = obj; 4583 return (0); 4584 } 4585 } 4586 } while ((*hashval++ & 1) == 0); 4587 if (matchres.vcount == 1) { 4588 req->sym_out = matchres.vsymp; 4589 req->defobj_out = obj; 4590 return (0); 4591 } 4592 return (ESRCH); 4593 } 4594 4595 static void 4596 trace_loaded_objects(Obj_Entry *obj) 4597 { 4598 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4599 int c; 4600 4601 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4602 main_local = ""; 4603 4604 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4605 fmt1 = "\t%o => %p (%x)\n"; 4606 4607 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4608 fmt2 = "\t%o (%x)\n"; 4609 4610 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4611 4612 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4613 Needed_Entry *needed; 4614 const char *name, *path; 4615 bool is_lib; 4616 4617 if (obj->marker) 4618 continue; 4619 if (list_containers && obj->needed != NULL) 4620 rtld_printf("%s:\n", obj->path); 4621 for (needed = obj->needed; needed; needed = needed->next) { 4622 if (needed->obj != NULL) { 4623 if (needed->obj->traced && !list_containers) 4624 continue; 4625 needed->obj->traced = true; 4626 path = needed->obj->path; 4627 } else 4628 path = "not found"; 4629 4630 name = obj->strtab + needed->name; 4631 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4632 4633 fmt = is_lib ? fmt1 : fmt2; 4634 while ((c = *fmt++) != '\0') { 4635 switch (c) { 4636 default: 4637 rtld_putchar(c); 4638 continue; 4639 case '\\': 4640 switch (c = *fmt) { 4641 case '\0': 4642 continue; 4643 case 'n': 4644 rtld_putchar('\n'); 4645 break; 4646 case 't': 4647 rtld_putchar('\t'); 4648 break; 4649 } 4650 break; 4651 case '%': 4652 switch (c = *fmt) { 4653 case '\0': 4654 continue; 4655 case '%': 4656 default: 4657 rtld_putchar(c); 4658 break; 4659 case 'A': 4660 rtld_putstr(main_local); 4661 break; 4662 case 'a': 4663 rtld_putstr(obj_main->path); 4664 break; 4665 case 'o': 4666 rtld_putstr(name); 4667 break; 4668 #if 0 4669 case 'm': 4670 rtld_printf("%d", sodp->sod_major); 4671 break; 4672 case 'n': 4673 rtld_printf("%d", sodp->sod_minor); 4674 break; 4675 #endif 4676 case 'p': 4677 rtld_putstr(path); 4678 break; 4679 case 'x': 4680 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4681 0); 4682 break; 4683 } 4684 break; 4685 } 4686 ++fmt; 4687 } 4688 } 4689 } 4690 } 4691 4692 /* 4693 * Unload a dlopened object and its dependencies from memory and from 4694 * our data structures. It is assumed that the DAG rooted in the 4695 * object has already been unreferenced, and that the object has a 4696 * reference count of 0. 4697 */ 4698 static void 4699 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4700 { 4701 Obj_Entry marker, *obj, *next; 4702 4703 assert(root->refcount == 0); 4704 4705 /* 4706 * Pass over the DAG removing unreferenced objects from 4707 * appropriate lists. 4708 */ 4709 unlink_object(root); 4710 4711 /* Unmap all objects that are no longer referenced. */ 4712 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4713 next = TAILQ_NEXT(obj, next); 4714 if (obj->marker || obj->refcount != 0) 4715 continue; 4716 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4717 obj->mapsize, 0, obj->path); 4718 dbg("unloading \"%s\"", obj->path); 4719 /* 4720 * Unlink the object now to prevent new references from 4721 * being acquired while the bind lock is dropped in 4722 * recursive dlclose() invocations. 4723 */ 4724 TAILQ_REMOVE(&obj_list, obj, next); 4725 obj_count--; 4726 4727 if (obj->filtees_loaded) { 4728 if (next != NULL) { 4729 init_marker(&marker); 4730 TAILQ_INSERT_BEFORE(next, &marker, next); 4731 unload_filtees(obj, lockstate); 4732 next = TAILQ_NEXT(&marker, next); 4733 TAILQ_REMOVE(&obj_list, &marker, next); 4734 } else 4735 unload_filtees(obj, lockstate); 4736 } 4737 release_object(obj); 4738 } 4739 } 4740 4741 static void 4742 unlink_object(Obj_Entry *root) 4743 { 4744 Objlist_Entry *elm; 4745 4746 if (root->refcount == 0) { 4747 /* Remove the object from the RTLD_GLOBAL list. */ 4748 objlist_remove(&list_global, root); 4749 4750 /* Remove the object from all objects' DAG lists. */ 4751 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4752 objlist_remove(&elm->obj->dldags, root); 4753 if (elm->obj != root) 4754 unlink_object(elm->obj); 4755 } 4756 } 4757 } 4758 4759 static void 4760 ref_dag(Obj_Entry *root) 4761 { 4762 Objlist_Entry *elm; 4763 4764 assert(root->dag_inited); 4765 STAILQ_FOREACH(elm, &root->dagmembers, link) 4766 elm->obj->refcount++; 4767 } 4768 4769 static void 4770 unref_dag(Obj_Entry *root) 4771 { 4772 Objlist_Entry *elm; 4773 4774 assert(root->dag_inited); 4775 STAILQ_FOREACH(elm, &root->dagmembers, link) 4776 elm->obj->refcount--; 4777 } 4778 4779 /* 4780 * Common code for MD __tls_get_addr(). 4781 */ 4782 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4783 static void * 4784 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4785 { 4786 Elf_Addr *newdtv, *dtv; 4787 RtldLockState lockstate; 4788 int to_copy; 4789 4790 dtv = *dtvp; 4791 /* Check dtv generation in case new modules have arrived */ 4792 if (dtv[0] != tls_dtv_generation) { 4793 wlock_acquire(rtld_bind_lock, &lockstate); 4794 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4795 to_copy = dtv[1]; 4796 if (to_copy > tls_max_index) 4797 to_copy = tls_max_index; 4798 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4799 newdtv[0] = tls_dtv_generation; 4800 newdtv[1] = tls_max_index; 4801 free(dtv); 4802 lock_release(rtld_bind_lock, &lockstate); 4803 dtv = *dtvp = newdtv; 4804 } 4805 4806 /* Dynamically allocate module TLS if necessary */ 4807 if (dtv[index + 1] == 0) { 4808 /* Signal safe, wlock will block out signals. */ 4809 wlock_acquire(rtld_bind_lock, &lockstate); 4810 if (!dtv[index + 1]) 4811 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4812 lock_release(rtld_bind_lock, &lockstate); 4813 } 4814 return ((void *)(dtv[index + 1] + offset)); 4815 } 4816 4817 void * 4818 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4819 { 4820 Elf_Addr *dtv; 4821 4822 dtv = *dtvp; 4823 /* Check dtv generation in case new modules have arrived */ 4824 if (__predict_true(dtv[0] == tls_dtv_generation && 4825 dtv[index + 1] != 0)) 4826 return ((void *)(dtv[index + 1] + offset)); 4827 return (tls_get_addr_slow(dtvp, index, offset)); 4828 } 4829 4830 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4831 defined(__powerpc__) || defined(__riscv) 4832 4833 /* 4834 * Return pointer to allocated TLS block 4835 */ 4836 static void * 4837 get_tls_block_ptr(void *tcb, size_t tcbsize) 4838 { 4839 size_t extra_size, post_size, pre_size, tls_block_size; 4840 size_t tls_init_align; 4841 4842 tls_init_align = MAX(obj_main->tlsalign, 1); 4843 4844 /* Compute fragments sizes. */ 4845 extra_size = tcbsize - TLS_TCB_SIZE; 4846 post_size = calculate_tls_post_size(tls_init_align); 4847 tls_block_size = tcbsize + post_size; 4848 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4849 4850 return ((char *)tcb - pre_size - extra_size); 4851 } 4852 4853 /* 4854 * Allocate Static TLS using the Variant I method. 4855 * 4856 * For details on the layout, see lib/libc/gen/tls.c. 4857 * 4858 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4859 * it is based on tls_last_offset, and TLS offsets here are really TCB 4860 * offsets, whereas libc's tls_static_space is just the executable's static 4861 * TLS segment. 4862 */ 4863 void * 4864 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4865 { 4866 Obj_Entry *obj; 4867 char *tls_block; 4868 Elf_Addr *dtv, **tcb; 4869 Elf_Addr addr; 4870 Elf_Addr i; 4871 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4872 size_t tls_init_align, tls_init_offset; 4873 4874 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4875 return (oldtcb); 4876 4877 assert(tcbsize >= TLS_TCB_SIZE); 4878 maxalign = MAX(tcbalign, tls_static_max_align); 4879 tls_init_align = MAX(obj_main->tlsalign, 1); 4880 4881 /* Compute fragmets sizes. */ 4882 extra_size = tcbsize - TLS_TCB_SIZE; 4883 post_size = calculate_tls_post_size(tls_init_align); 4884 tls_block_size = tcbsize + post_size; 4885 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4886 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4887 4888 /* Allocate whole TLS block */ 4889 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4890 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4891 4892 if (oldtcb != NULL) { 4893 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4894 tls_static_space); 4895 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4896 4897 /* Adjust the DTV. */ 4898 dtv = tcb[0]; 4899 for (i = 0; i < dtv[1]; i++) { 4900 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4901 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4902 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4903 } 4904 } 4905 } else { 4906 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4907 tcb[0] = dtv; 4908 dtv[0] = tls_dtv_generation; 4909 dtv[1] = tls_max_index; 4910 4911 for (obj = globallist_curr(objs); obj != NULL; 4912 obj = globallist_next(obj)) { 4913 if (obj->tlsoffset == 0) 4914 continue; 4915 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4916 addr = (Elf_Addr)tcb + obj->tlsoffset; 4917 if (tls_init_offset > 0) 4918 memset((void *)addr, 0, tls_init_offset); 4919 if (obj->tlsinitsize > 0) { 4920 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4921 obj->tlsinitsize); 4922 } 4923 if (obj->tlssize > obj->tlsinitsize) { 4924 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4925 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4926 } 4927 dtv[obj->tlsindex + 1] = addr; 4928 } 4929 } 4930 4931 return (tcb); 4932 } 4933 4934 void 4935 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4936 { 4937 Elf_Addr *dtv; 4938 Elf_Addr tlsstart, tlsend; 4939 size_t post_size; 4940 size_t dtvsize, i, tls_init_align; 4941 4942 assert(tcbsize >= TLS_TCB_SIZE); 4943 tls_init_align = MAX(obj_main->tlsalign, 1); 4944 4945 /* Compute fragments sizes. */ 4946 post_size = calculate_tls_post_size(tls_init_align); 4947 4948 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4949 tlsend = (Elf_Addr)tcb + tls_static_space; 4950 4951 dtv = *(Elf_Addr **)tcb; 4952 dtvsize = dtv[1]; 4953 for (i = 0; i < dtvsize; i++) { 4954 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4955 free((void*)dtv[i+2]); 4956 } 4957 } 4958 free(dtv); 4959 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4960 } 4961 4962 #endif 4963 4964 #if defined(__i386__) || defined(__amd64__) 4965 4966 /* 4967 * Allocate Static TLS using the Variant II method. 4968 */ 4969 void * 4970 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4971 { 4972 Obj_Entry *obj; 4973 size_t size, ralign; 4974 char *tls; 4975 Elf_Addr *dtv, *olddtv; 4976 Elf_Addr segbase, oldsegbase, addr; 4977 size_t i; 4978 4979 ralign = tcbalign; 4980 if (tls_static_max_align > ralign) 4981 ralign = tls_static_max_align; 4982 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4983 4984 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4985 tls = malloc_aligned(size, ralign, 0 /* XXX */); 4986 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4987 4988 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4989 ((Elf_Addr*)segbase)[0] = segbase; 4990 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4991 4992 dtv[0] = tls_dtv_generation; 4993 dtv[1] = tls_max_index; 4994 4995 if (oldtls) { 4996 /* 4997 * Copy the static TLS block over whole. 4998 */ 4999 oldsegbase = (Elf_Addr) oldtls; 5000 memcpy((void *)(segbase - tls_static_space), 5001 (const void *)(oldsegbase - tls_static_space), 5002 tls_static_space); 5003 5004 /* 5005 * If any dynamic TLS blocks have been created tls_get_addr(), 5006 * move them over. 5007 */ 5008 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5009 for (i = 0; i < olddtv[1]; i++) { 5010 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5011 dtv[i+2] = olddtv[i+2]; 5012 olddtv[i+2] = 0; 5013 } 5014 } 5015 5016 /* 5017 * We assume that this block was the one we created with 5018 * allocate_initial_tls(). 5019 */ 5020 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5021 } else { 5022 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5023 if (obj->marker || obj->tlsoffset == 0) 5024 continue; 5025 addr = segbase - obj->tlsoffset; 5026 memset((void*)(addr + obj->tlsinitsize), 5027 0, obj->tlssize - obj->tlsinitsize); 5028 if (obj->tlsinit) { 5029 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5030 obj->static_tls_copied = true; 5031 } 5032 dtv[obj->tlsindex + 1] = addr; 5033 } 5034 } 5035 5036 return (void*) segbase; 5037 } 5038 5039 void 5040 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5041 { 5042 Elf_Addr* dtv; 5043 size_t size, ralign; 5044 int dtvsize, i; 5045 Elf_Addr tlsstart, tlsend; 5046 5047 /* 5048 * Figure out the size of the initial TLS block so that we can 5049 * find stuff which ___tls_get_addr() allocated dynamically. 5050 */ 5051 ralign = tcbalign; 5052 if (tls_static_max_align > ralign) 5053 ralign = tls_static_max_align; 5054 size = round(tls_static_space, ralign); 5055 5056 dtv = ((Elf_Addr**)tls)[1]; 5057 dtvsize = dtv[1]; 5058 tlsend = (Elf_Addr) tls; 5059 tlsstart = tlsend - size; 5060 for (i = 0; i < dtvsize; i++) { 5061 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5062 free_aligned((void *)dtv[i + 2]); 5063 } 5064 } 5065 5066 free_aligned((void *)tlsstart); 5067 free((void*) dtv); 5068 } 5069 5070 #endif 5071 5072 /* 5073 * Allocate TLS block for module with given index. 5074 */ 5075 void * 5076 allocate_module_tls(int index) 5077 { 5078 Obj_Entry *obj; 5079 char *p; 5080 5081 TAILQ_FOREACH(obj, &obj_list, next) { 5082 if (obj->marker) 5083 continue; 5084 if (obj->tlsindex == index) 5085 break; 5086 } 5087 if (obj == NULL) { 5088 _rtld_error("Can't find module with TLS index %d", index); 5089 rtld_die(); 5090 } 5091 5092 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5093 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5094 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5095 return (p); 5096 } 5097 5098 bool 5099 allocate_tls_offset(Obj_Entry *obj) 5100 { 5101 size_t off; 5102 5103 if (obj->tls_done) 5104 return true; 5105 5106 if (obj->tlssize == 0) { 5107 obj->tls_done = true; 5108 return true; 5109 } 5110 5111 if (tls_last_offset == 0) 5112 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5113 else 5114 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5115 obj->tlssize, obj->tlsalign); 5116 5117 /* 5118 * If we have already fixed the size of the static TLS block, we 5119 * must stay within that size. When allocating the static TLS, we 5120 * leave a small amount of space spare to be used for dynamically 5121 * loading modules which use static TLS. 5122 */ 5123 if (tls_static_space != 0) { 5124 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5125 return false; 5126 } else if (obj->tlsalign > tls_static_max_align) { 5127 tls_static_max_align = obj->tlsalign; 5128 } 5129 5130 tls_last_offset = obj->tlsoffset = off; 5131 tls_last_size = obj->tlssize; 5132 obj->tls_done = true; 5133 5134 return true; 5135 } 5136 5137 void 5138 free_tls_offset(Obj_Entry *obj) 5139 { 5140 5141 /* 5142 * If we were the last thing to allocate out of the static TLS 5143 * block, we give our space back to the 'allocator'. This is a 5144 * simplistic workaround to allow libGL.so.1 to be loaded and 5145 * unloaded multiple times. 5146 */ 5147 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5148 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5149 tls_last_offset -= obj->tlssize; 5150 tls_last_size = 0; 5151 } 5152 } 5153 5154 void * 5155 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5156 { 5157 void *ret; 5158 RtldLockState lockstate; 5159 5160 wlock_acquire(rtld_bind_lock, &lockstate); 5161 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5162 tcbsize, tcbalign); 5163 lock_release(rtld_bind_lock, &lockstate); 5164 return (ret); 5165 } 5166 5167 void 5168 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5169 { 5170 RtldLockState lockstate; 5171 5172 wlock_acquire(rtld_bind_lock, &lockstate); 5173 free_tls(tcb, tcbsize, tcbalign); 5174 lock_release(rtld_bind_lock, &lockstate); 5175 } 5176 5177 static void 5178 object_add_name(Obj_Entry *obj, const char *name) 5179 { 5180 Name_Entry *entry; 5181 size_t len; 5182 5183 len = strlen(name); 5184 entry = malloc(sizeof(Name_Entry) + len); 5185 5186 if (entry != NULL) { 5187 strcpy(entry->name, name); 5188 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5189 } 5190 } 5191 5192 static int 5193 object_match_name(const Obj_Entry *obj, const char *name) 5194 { 5195 Name_Entry *entry; 5196 5197 STAILQ_FOREACH(entry, &obj->names, link) { 5198 if (strcmp(name, entry->name) == 0) 5199 return (1); 5200 } 5201 return (0); 5202 } 5203 5204 static Obj_Entry * 5205 locate_dependency(const Obj_Entry *obj, const char *name) 5206 { 5207 const Objlist_Entry *entry; 5208 const Needed_Entry *needed; 5209 5210 STAILQ_FOREACH(entry, &list_main, link) { 5211 if (object_match_name(entry->obj, name)) 5212 return entry->obj; 5213 } 5214 5215 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5216 if (strcmp(obj->strtab + needed->name, name) == 0 || 5217 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5218 /* 5219 * If there is DT_NEEDED for the name we are looking for, 5220 * we are all set. Note that object might not be found if 5221 * dependency was not loaded yet, so the function can 5222 * return NULL here. This is expected and handled 5223 * properly by the caller. 5224 */ 5225 return (needed->obj); 5226 } 5227 } 5228 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5229 obj->path, name); 5230 rtld_die(); 5231 } 5232 5233 static int 5234 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5235 const Elf_Vernaux *vna) 5236 { 5237 const Elf_Verdef *vd; 5238 const char *vername; 5239 5240 vername = refobj->strtab + vna->vna_name; 5241 vd = depobj->verdef; 5242 if (vd == NULL) { 5243 _rtld_error("%s: version %s required by %s not defined", 5244 depobj->path, vername, refobj->path); 5245 return (-1); 5246 } 5247 for (;;) { 5248 if (vd->vd_version != VER_DEF_CURRENT) { 5249 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5250 depobj->path, vd->vd_version); 5251 return (-1); 5252 } 5253 if (vna->vna_hash == vd->vd_hash) { 5254 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5255 ((const char *)vd + vd->vd_aux); 5256 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5257 return (0); 5258 } 5259 if (vd->vd_next == 0) 5260 break; 5261 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5262 } 5263 if (vna->vna_flags & VER_FLG_WEAK) 5264 return (0); 5265 _rtld_error("%s: version %s required by %s not found", 5266 depobj->path, vername, refobj->path); 5267 return (-1); 5268 } 5269 5270 static int 5271 rtld_verify_object_versions(Obj_Entry *obj) 5272 { 5273 const Elf_Verneed *vn; 5274 const Elf_Verdef *vd; 5275 const Elf_Verdaux *vda; 5276 const Elf_Vernaux *vna; 5277 const Obj_Entry *depobj; 5278 int maxvernum, vernum; 5279 5280 if (obj->ver_checked) 5281 return (0); 5282 obj->ver_checked = true; 5283 5284 maxvernum = 0; 5285 /* 5286 * Walk over defined and required version records and figure out 5287 * max index used by any of them. Do very basic sanity checking 5288 * while there. 5289 */ 5290 vn = obj->verneed; 5291 while (vn != NULL) { 5292 if (vn->vn_version != VER_NEED_CURRENT) { 5293 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5294 obj->path, vn->vn_version); 5295 return (-1); 5296 } 5297 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5298 for (;;) { 5299 vernum = VER_NEED_IDX(vna->vna_other); 5300 if (vernum > maxvernum) 5301 maxvernum = vernum; 5302 if (vna->vna_next == 0) 5303 break; 5304 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5305 } 5306 if (vn->vn_next == 0) 5307 break; 5308 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5309 } 5310 5311 vd = obj->verdef; 5312 while (vd != NULL) { 5313 if (vd->vd_version != VER_DEF_CURRENT) { 5314 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5315 obj->path, vd->vd_version); 5316 return (-1); 5317 } 5318 vernum = VER_DEF_IDX(vd->vd_ndx); 5319 if (vernum > maxvernum) 5320 maxvernum = vernum; 5321 if (vd->vd_next == 0) 5322 break; 5323 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5324 } 5325 5326 if (maxvernum == 0) 5327 return (0); 5328 5329 /* 5330 * Store version information in array indexable by version index. 5331 * Verify that object version requirements are satisfied along the 5332 * way. 5333 */ 5334 obj->vernum = maxvernum + 1; 5335 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5336 5337 vd = obj->verdef; 5338 while (vd != NULL) { 5339 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5340 vernum = VER_DEF_IDX(vd->vd_ndx); 5341 assert(vernum <= maxvernum); 5342 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5343 obj->vertab[vernum].hash = vd->vd_hash; 5344 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5345 obj->vertab[vernum].file = NULL; 5346 obj->vertab[vernum].flags = 0; 5347 } 5348 if (vd->vd_next == 0) 5349 break; 5350 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5351 } 5352 5353 vn = obj->verneed; 5354 while (vn != NULL) { 5355 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5356 if (depobj == NULL) 5357 return (-1); 5358 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5359 for (;;) { 5360 if (check_object_provided_version(obj, depobj, vna)) 5361 return (-1); 5362 vernum = VER_NEED_IDX(vna->vna_other); 5363 assert(vernum <= maxvernum); 5364 obj->vertab[vernum].hash = vna->vna_hash; 5365 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5366 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5367 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5368 VER_INFO_HIDDEN : 0; 5369 if (vna->vna_next == 0) 5370 break; 5371 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5372 } 5373 if (vn->vn_next == 0) 5374 break; 5375 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5376 } 5377 return 0; 5378 } 5379 5380 static int 5381 rtld_verify_versions(const Objlist *objlist) 5382 { 5383 Objlist_Entry *entry; 5384 int rc; 5385 5386 rc = 0; 5387 STAILQ_FOREACH(entry, objlist, link) { 5388 /* 5389 * Skip dummy objects or objects that have their version requirements 5390 * already checked. 5391 */ 5392 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5393 continue; 5394 if (rtld_verify_object_versions(entry->obj) == -1) { 5395 rc = -1; 5396 if (ld_tracing == NULL) 5397 break; 5398 } 5399 } 5400 if (rc == 0 || ld_tracing != NULL) 5401 rc = rtld_verify_object_versions(&obj_rtld); 5402 return rc; 5403 } 5404 5405 const Ver_Entry * 5406 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5407 { 5408 Elf_Versym vernum; 5409 5410 if (obj->vertab) { 5411 vernum = VER_NDX(obj->versyms[symnum]); 5412 if (vernum >= obj->vernum) { 5413 _rtld_error("%s: symbol %s has wrong verneed value %d", 5414 obj->path, obj->strtab + symnum, vernum); 5415 } else if (obj->vertab[vernum].hash != 0) { 5416 return &obj->vertab[vernum]; 5417 } 5418 } 5419 return NULL; 5420 } 5421 5422 int 5423 _rtld_get_stack_prot(void) 5424 { 5425 5426 return (stack_prot); 5427 } 5428 5429 int 5430 _rtld_is_dlopened(void *arg) 5431 { 5432 Obj_Entry *obj; 5433 RtldLockState lockstate; 5434 int res; 5435 5436 rlock_acquire(rtld_bind_lock, &lockstate); 5437 obj = dlcheck(arg); 5438 if (obj == NULL) 5439 obj = obj_from_addr(arg); 5440 if (obj == NULL) { 5441 _rtld_error("No shared object contains address"); 5442 lock_release(rtld_bind_lock, &lockstate); 5443 return (-1); 5444 } 5445 res = obj->dlopened ? 1 : 0; 5446 lock_release(rtld_bind_lock, &lockstate); 5447 return (res); 5448 } 5449 5450 static int 5451 obj_remap_relro(Obj_Entry *obj, int prot) 5452 { 5453 5454 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5455 prot) == -1) { 5456 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5457 obj->path, prot, rtld_strerror(errno)); 5458 return (-1); 5459 } 5460 return (0); 5461 } 5462 5463 static int 5464 obj_disable_relro(Obj_Entry *obj) 5465 { 5466 5467 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5468 } 5469 5470 static int 5471 obj_enforce_relro(Obj_Entry *obj) 5472 { 5473 5474 return (obj_remap_relro(obj, PROT_READ)); 5475 } 5476 5477 static void 5478 map_stacks_exec(RtldLockState *lockstate) 5479 { 5480 void (*thr_map_stacks_exec)(void); 5481 5482 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5483 return; 5484 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5485 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5486 if (thr_map_stacks_exec != NULL) { 5487 stack_prot |= PROT_EXEC; 5488 thr_map_stacks_exec(); 5489 } 5490 } 5491 5492 static void 5493 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5494 { 5495 Objlist_Entry *elm; 5496 Obj_Entry *obj; 5497 void (*distrib)(size_t, void *, size_t, size_t); 5498 5499 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5500 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5501 if (distrib == NULL) 5502 return; 5503 STAILQ_FOREACH(elm, list, link) { 5504 obj = elm->obj; 5505 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5506 continue; 5507 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5508 obj->tlssize); 5509 obj->static_tls_copied = true; 5510 } 5511 } 5512 5513 void 5514 symlook_init(SymLook *dst, const char *name) 5515 { 5516 5517 bzero(dst, sizeof(*dst)); 5518 dst->name = name; 5519 dst->hash = elf_hash(name); 5520 dst->hash_gnu = gnu_hash(name); 5521 } 5522 5523 static void 5524 symlook_init_from_req(SymLook *dst, const SymLook *src) 5525 { 5526 5527 dst->name = src->name; 5528 dst->hash = src->hash; 5529 dst->hash_gnu = src->hash_gnu; 5530 dst->ventry = src->ventry; 5531 dst->flags = src->flags; 5532 dst->defobj_out = NULL; 5533 dst->sym_out = NULL; 5534 dst->lockstate = src->lockstate; 5535 } 5536 5537 static int 5538 open_binary_fd(const char *argv0, bool search_in_path, 5539 const char **binpath_res) 5540 { 5541 char *binpath, *pathenv, *pe, *res1; 5542 const char *res; 5543 int fd; 5544 5545 binpath = NULL; 5546 res = NULL; 5547 if (search_in_path && strchr(argv0, '/') == NULL) { 5548 binpath = xmalloc(PATH_MAX); 5549 pathenv = getenv("PATH"); 5550 if (pathenv == NULL) { 5551 _rtld_error("-p and no PATH environment variable"); 5552 rtld_die(); 5553 } 5554 pathenv = strdup(pathenv); 5555 if (pathenv == NULL) { 5556 _rtld_error("Cannot allocate memory"); 5557 rtld_die(); 5558 } 5559 fd = -1; 5560 errno = ENOENT; 5561 while ((pe = strsep(&pathenv, ":")) != NULL) { 5562 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5563 continue; 5564 if (binpath[0] != '\0' && 5565 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5566 continue; 5567 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5568 continue; 5569 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5570 if (fd != -1 || errno != ENOENT) { 5571 res = binpath; 5572 break; 5573 } 5574 } 5575 free(pathenv); 5576 } else { 5577 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5578 res = argv0; 5579 } 5580 5581 if (fd == -1) { 5582 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5583 rtld_die(); 5584 } 5585 if (res != NULL && res[0] != '/') { 5586 res1 = xmalloc(PATH_MAX); 5587 if (realpath(res, res1) != NULL) { 5588 if (res != argv0) 5589 free(__DECONST(char *, res)); 5590 res = res1; 5591 } else { 5592 free(res1); 5593 } 5594 } 5595 *binpath_res = res; 5596 return (fd); 5597 } 5598 5599 /* 5600 * Parse a set of command-line arguments. 5601 */ 5602 static int 5603 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5604 { 5605 const char *arg; 5606 int fd, i, j, arglen; 5607 char opt; 5608 5609 dbg("Parsing command-line arguments"); 5610 *use_pathp = false; 5611 *fdp = -1; 5612 5613 for (i = 1; i < argc; i++ ) { 5614 arg = argv[i]; 5615 dbg("argv[%d]: '%s'", i, arg); 5616 5617 /* 5618 * rtld arguments end with an explicit "--" or with the first 5619 * non-prefixed argument. 5620 */ 5621 if (strcmp(arg, "--") == 0) { 5622 i++; 5623 break; 5624 } 5625 if (arg[0] != '-') 5626 break; 5627 5628 /* 5629 * All other arguments are single-character options that can 5630 * be combined, so we need to search through `arg` for them. 5631 */ 5632 arglen = strlen(arg); 5633 for (j = 1; j < arglen; j++) { 5634 opt = arg[j]; 5635 if (opt == 'h') { 5636 print_usage(argv[0]); 5637 _exit(0); 5638 } else if (opt == 'f') { 5639 /* 5640 * -f XX can be used to specify a 5641 * descriptor for the binary named at 5642 * the command line (i.e., the later 5643 * argument will specify the process 5644 * name but the descriptor is what 5645 * will actually be executed). 5646 * 5647 * -f must be the last option in, e.g., -abcf. 5648 */ 5649 if (j != arglen - 1) { 5650 _rtld_error("Invalid options: %s", arg); 5651 rtld_die(); 5652 } 5653 i++; 5654 fd = parse_integer(argv[i]); 5655 if (fd == -1) { 5656 _rtld_error( 5657 "Invalid file descriptor: '%s'", 5658 argv[i]); 5659 rtld_die(); 5660 } 5661 *fdp = fd; 5662 break; 5663 } else if (opt == 'p') { 5664 *use_pathp = true; 5665 } else { 5666 _rtld_error("Invalid argument: '%s'", arg); 5667 print_usage(argv[0]); 5668 rtld_die(); 5669 } 5670 } 5671 } 5672 5673 return (i); 5674 } 5675 5676 /* 5677 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5678 */ 5679 static int 5680 parse_integer(const char *str) 5681 { 5682 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5683 const char *orig; 5684 int n; 5685 char c; 5686 5687 orig = str; 5688 n = 0; 5689 for (c = *str; c != '\0'; c = *++str) { 5690 if (c < '0' || c > '9') 5691 return (-1); 5692 5693 n *= RADIX; 5694 n += c - '0'; 5695 } 5696 5697 /* Make sure we actually parsed something. */ 5698 if (str == orig) 5699 return (-1); 5700 return (n); 5701 } 5702 5703 static void 5704 print_usage(const char *argv0) 5705 { 5706 5707 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5708 "\n" 5709 "Options:\n" 5710 " -h Display this help message\n" 5711 " -p Search in PATH for named binary\n" 5712 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5713 " -- End of RTLD options\n" 5714 " <binary> Name of process to execute\n" 5715 " <args> Arguments to the executed process\n", argv0); 5716 } 5717 5718 /* 5719 * Overrides for libc_pic-provided functions. 5720 */ 5721 5722 int 5723 __getosreldate(void) 5724 { 5725 size_t len; 5726 int oid[2]; 5727 int error, osrel; 5728 5729 if (osreldate != 0) 5730 return (osreldate); 5731 5732 oid[0] = CTL_KERN; 5733 oid[1] = KERN_OSRELDATE; 5734 osrel = 0; 5735 len = sizeof(osrel); 5736 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5737 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5738 osreldate = osrel; 5739 return (osreldate); 5740 } 5741 const char * 5742 rtld_strerror(int errnum) 5743 { 5744 5745 if (errnum < 0 || errnum >= sys_nerr) 5746 return ("Unknown error"); 5747 return (sys_errlist[errnum]); 5748 } 5749 5750 /* malloc */ 5751 void * 5752 malloc(size_t nbytes) 5753 { 5754 5755 return (__crt_malloc(nbytes)); 5756 } 5757 5758 void * 5759 calloc(size_t num, size_t size) 5760 { 5761 5762 return (__crt_calloc(num, size)); 5763 } 5764 5765 void 5766 free(void *cp) 5767 { 5768 5769 __crt_free(cp); 5770 } 5771 5772 void * 5773 realloc(void *cp, size_t nbytes) 5774 { 5775 5776 return (__crt_realloc(cp, nbytes)); 5777 } 5778