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 break; 1505 1506 case PT_GNU_STACK: 1507 obj->stack_flags = ph->p_flags; 1508 break; 1509 1510 case PT_GNU_RELRO: 1511 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1512 obj->relro_size = round_page(ph->p_memsz); 1513 break; 1514 1515 case PT_NOTE: 1516 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1517 note_end = note_start + ph->p_filesz; 1518 digest_notes(obj, note_start, note_end); 1519 break; 1520 } 1521 } 1522 if (nsegs < 1) { 1523 _rtld_error("%s: too few PT_LOAD segments", path); 1524 return NULL; 1525 } 1526 1527 obj->entry = entry; 1528 return obj; 1529 } 1530 1531 void 1532 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1533 { 1534 const Elf_Note *note; 1535 const char *note_name; 1536 uintptr_t p; 1537 1538 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1539 note = (const Elf_Note *)((const char *)(note + 1) + 1540 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1541 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1542 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1543 note->n_descsz != sizeof(int32_t)) 1544 continue; 1545 if (note->n_type != NT_FREEBSD_ABI_TAG && 1546 note->n_type != NT_FREEBSD_FEATURE_CTL && 1547 note->n_type != NT_FREEBSD_NOINIT_TAG) 1548 continue; 1549 note_name = (const char *)(note + 1); 1550 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1551 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1552 continue; 1553 switch (note->n_type) { 1554 case NT_FREEBSD_ABI_TAG: 1555 /* FreeBSD osrel note */ 1556 p = (uintptr_t)(note + 1); 1557 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1558 obj->osrel = *(const int32_t *)(p); 1559 dbg("note osrel %d", obj->osrel); 1560 break; 1561 case NT_FREEBSD_FEATURE_CTL: 1562 /* FreeBSD ABI feature control note */ 1563 p = (uintptr_t)(note + 1); 1564 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1565 obj->fctl0 = *(const uint32_t *)(p); 1566 dbg("note fctl0 %#x", obj->fctl0); 1567 break; 1568 case NT_FREEBSD_NOINIT_TAG: 1569 /* FreeBSD 'crt does not call init' note */ 1570 obj->crt_no_init = true; 1571 dbg("note crt_no_init"); 1572 break; 1573 } 1574 } 1575 } 1576 1577 static Obj_Entry * 1578 dlcheck(void *handle) 1579 { 1580 Obj_Entry *obj; 1581 1582 TAILQ_FOREACH(obj, &obj_list, next) { 1583 if (obj == (Obj_Entry *) handle) 1584 break; 1585 } 1586 1587 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1588 _rtld_error("Invalid shared object handle %p", handle); 1589 return NULL; 1590 } 1591 return obj; 1592 } 1593 1594 /* 1595 * If the given object is already in the donelist, return true. Otherwise 1596 * add the object to the list and return false. 1597 */ 1598 static bool 1599 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1600 { 1601 unsigned int i; 1602 1603 for (i = 0; i < dlp->num_used; i++) 1604 if (dlp->objs[i] == obj) 1605 return true; 1606 /* 1607 * Our donelist allocation should always be sufficient. But if 1608 * our threads locking isn't working properly, more shared objects 1609 * could have been loaded since we allocated the list. That should 1610 * never happen, but we'll handle it properly just in case it does. 1611 */ 1612 if (dlp->num_used < dlp->num_alloc) 1613 dlp->objs[dlp->num_used++] = obj; 1614 return false; 1615 } 1616 1617 /* 1618 * Hash function for symbol table lookup. Don't even think about changing 1619 * this. It is specified by the System V ABI. 1620 */ 1621 unsigned long 1622 elf_hash(const char *name) 1623 { 1624 const unsigned char *p = (const unsigned char *) name; 1625 unsigned long h = 0; 1626 unsigned long g; 1627 1628 while (*p != '\0') { 1629 h = (h << 4) + *p++; 1630 if ((g = h & 0xf0000000) != 0) 1631 h ^= g >> 24; 1632 h &= ~g; 1633 } 1634 return h; 1635 } 1636 1637 /* 1638 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1639 * unsigned in case it's implemented with a wider type. 1640 */ 1641 static uint32_t 1642 gnu_hash(const char *s) 1643 { 1644 uint32_t h; 1645 unsigned char c; 1646 1647 h = 5381; 1648 for (c = *s; c != '\0'; c = *++s) 1649 h = h * 33 + c; 1650 return (h & 0xffffffff); 1651 } 1652 1653 1654 /* 1655 * Find the library with the given name, and return its full pathname. 1656 * The returned string is dynamically allocated. Generates an error 1657 * message and returns NULL if the library cannot be found. 1658 * 1659 * If the second argument is non-NULL, then it refers to an already- 1660 * loaded shared object, whose library search path will be searched. 1661 * 1662 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1663 * descriptor (which is close-on-exec) will be passed out via the third 1664 * argument. 1665 * 1666 * The search order is: 1667 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1668 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1669 * LD_LIBRARY_PATH 1670 * DT_RUNPATH in the referencing file 1671 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1672 * from list) 1673 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1674 * 1675 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1676 */ 1677 static char * 1678 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1679 { 1680 char *pathname, *refobj_path; 1681 const char *name; 1682 bool nodeflib, objgiven; 1683 1684 objgiven = refobj != NULL; 1685 1686 if (libmap_disable || !objgiven || 1687 (name = lm_find(refobj->path, xname)) == NULL) 1688 name = xname; 1689 1690 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1691 if (name[0] != '/' && !trust) { 1692 _rtld_error("Absolute pathname required " 1693 "for shared object \"%s\"", name); 1694 return (NULL); 1695 } 1696 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1697 __DECONST(char *, name))); 1698 } 1699 1700 dbg(" Searching for \"%s\"", name); 1701 refobj_path = objgiven ? refobj->path : NULL; 1702 1703 /* 1704 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1705 * back to pre-conforming behaviour if user requested so with 1706 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1707 * nodeflib. 1708 */ 1709 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1710 pathname = search_library_path(name, ld_library_path, 1711 refobj_path, fdp); 1712 if (pathname != NULL) 1713 return (pathname); 1714 if (refobj != NULL) { 1715 pathname = search_library_path(name, refobj->rpath, 1716 refobj_path, fdp); 1717 if (pathname != NULL) 1718 return (pathname); 1719 } 1720 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1721 if (pathname != NULL) 1722 return (pathname); 1723 pathname = search_library_path(name, gethints(false), 1724 refobj_path, fdp); 1725 if (pathname != NULL) 1726 return (pathname); 1727 pathname = search_library_path(name, ld_standard_library_path, 1728 refobj_path, fdp); 1729 if (pathname != NULL) 1730 return (pathname); 1731 } else { 1732 nodeflib = objgiven ? refobj->z_nodeflib : false; 1733 if (objgiven) { 1734 pathname = search_library_path(name, refobj->rpath, 1735 refobj->path, fdp); 1736 if (pathname != NULL) 1737 return (pathname); 1738 } 1739 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1740 pathname = search_library_path(name, obj_main->rpath, 1741 refobj_path, fdp); 1742 if (pathname != NULL) 1743 return (pathname); 1744 } 1745 pathname = search_library_path(name, ld_library_path, 1746 refobj_path, fdp); 1747 if (pathname != NULL) 1748 return (pathname); 1749 if (objgiven) { 1750 pathname = search_library_path(name, refobj->runpath, 1751 refobj_path, fdp); 1752 if (pathname != NULL) 1753 return (pathname); 1754 } 1755 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1756 if (pathname != NULL) 1757 return (pathname); 1758 pathname = search_library_path(name, gethints(nodeflib), 1759 refobj_path, fdp); 1760 if (pathname != NULL) 1761 return (pathname); 1762 if (objgiven && !nodeflib) { 1763 pathname = search_library_path(name, 1764 ld_standard_library_path, refobj_path, fdp); 1765 if (pathname != NULL) 1766 return (pathname); 1767 } 1768 } 1769 1770 if (objgiven && refobj->path != NULL) { 1771 _rtld_error("Shared object \"%s\" not found, " 1772 "required by \"%s\"", name, basename(refobj->path)); 1773 } else { 1774 _rtld_error("Shared object \"%s\" not found", name); 1775 } 1776 return (NULL); 1777 } 1778 1779 /* 1780 * Given a symbol number in a referencing object, find the corresponding 1781 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1782 * no definition was found. Returns a pointer to the Obj_Entry of the 1783 * defining object via the reference parameter DEFOBJ_OUT. 1784 */ 1785 const Elf_Sym * 1786 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1787 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1788 RtldLockState *lockstate) 1789 { 1790 const Elf_Sym *ref; 1791 const Elf_Sym *def; 1792 const Obj_Entry *defobj; 1793 const Ver_Entry *ve; 1794 SymLook req; 1795 const char *name; 1796 int res; 1797 1798 /* 1799 * If we have already found this symbol, get the information from 1800 * the cache. 1801 */ 1802 if (symnum >= refobj->dynsymcount) 1803 return NULL; /* Bad object */ 1804 if (cache != NULL && cache[symnum].sym != NULL) { 1805 *defobj_out = cache[symnum].obj; 1806 return cache[symnum].sym; 1807 } 1808 1809 ref = refobj->symtab + symnum; 1810 name = refobj->strtab + ref->st_name; 1811 def = NULL; 1812 defobj = NULL; 1813 ve = NULL; 1814 1815 /* 1816 * We don't have to do a full scale lookup if the symbol is local. 1817 * We know it will bind to the instance in this load module; to 1818 * which we already have a pointer (ie ref). By not doing a lookup, 1819 * we not only improve performance, but it also avoids unresolvable 1820 * symbols when local symbols are not in the hash table. This has 1821 * been seen with the ia64 toolchain. 1822 */ 1823 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1824 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1825 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1826 symnum); 1827 } 1828 symlook_init(&req, name); 1829 req.flags = flags; 1830 ve = req.ventry = fetch_ventry(refobj, symnum); 1831 req.lockstate = lockstate; 1832 res = symlook_default(&req, refobj); 1833 if (res == 0) { 1834 def = req.sym_out; 1835 defobj = req.defobj_out; 1836 } 1837 } else { 1838 def = ref; 1839 defobj = refobj; 1840 } 1841 1842 /* 1843 * If we found no definition and the reference is weak, treat the 1844 * symbol as having the value zero. 1845 */ 1846 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1847 def = &sym_zero; 1848 defobj = obj_main; 1849 } 1850 1851 if (def != NULL) { 1852 *defobj_out = defobj; 1853 /* Record the information in the cache to avoid subsequent lookups. */ 1854 if (cache != NULL) { 1855 cache[symnum].sym = def; 1856 cache[symnum].obj = defobj; 1857 } 1858 } else { 1859 if (refobj != &obj_rtld) 1860 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1861 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1862 } 1863 return def; 1864 } 1865 1866 /* 1867 * Return the search path from the ldconfig hints file, reading it if 1868 * necessary. If nostdlib is true, then the default search paths are 1869 * not added to result. 1870 * 1871 * Returns NULL if there are problems with the hints file, 1872 * or if the search path there is empty. 1873 */ 1874 static const char * 1875 gethints(bool nostdlib) 1876 { 1877 static char *filtered_path; 1878 static const char *hints; 1879 static struct elfhints_hdr hdr; 1880 struct fill_search_info_args sargs, hargs; 1881 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1882 struct dl_serpath *SLPpath, *hintpath; 1883 char *p; 1884 struct stat hint_stat; 1885 unsigned int SLPndx, hintndx, fndx, fcount; 1886 int fd; 1887 size_t flen; 1888 uint32_t dl; 1889 bool skip; 1890 1891 /* First call, read the hints file */ 1892 if (hints == NULL) { 1893 /* Keep from trying again in case the hints file is bad. */ 1894 hints = ""; 1895 1896 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1897 return (NULL); 1898 1899 /* 1900 * Check of hdr.dirlistlen value against type limit 1901 * intends to pacify static analyzers. Further 1902 * paranoia leads to checks that dirlist is fully 1903 * contained in the file range. 1904 */ 1905 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1906 hdr.magic != ELFHINTS_MAGIC || 1907 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1908 fstat(fd, &hint_stat) == -1) { 1909 cleanup1: 1910 close(fd); 1911 hdr.dirlistlen = 0; 1912 return (NULL); 1913 } 1914 dl = hdr.strtab; 1915 if (dl + hdr.dirlist < dl) 1916 goto cleanup1; 1917 dl += hdr.dirlist; 1918 if (dl + hdr.dirlistlen < dl) 1919 goto cleanup1; 1920 dl += hdr.dirlistlen; 1921 if (dl > hint_stat.st_size) 1922 goto cleanup1; 1923 p = xmalloc(hdr.dirlistlen + 1); 1924 if (pread(fd, p, hdr.dirlistlen + 1, 1925 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1926 p[hdr.dirlistlen] != '\0') { 1927 free(p); 1928 goto cleanup1; 1929 } 1930 hints = p; 1931 close(fd); 1932 } 1933 1934 /* 1935 * If caller agreed to receive list which includes the default 1936 * paths, we are done. Otherwise, if we still did not 1937 * calculated filtered result, do it now. 1938 */ 1939 if (!nostdlib) 1940 return (hints[0] != '\0' ? hints : NULL); 1941 if (filtered_path != NULL) 1942 goto filt_ret; 1943 1944 /* 1945 * Obtain the list of all configured search paths, and the 1946 * list of the default paths. 1947 * 1948 * First estimate the size of the results. 1949 */ 1950 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1951 smeta.dls_cnt = 0; 1952 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1953 hmeta.dls_cnt = 0; 1954 1955 sargs.request = RTLD_DI_SERINFOSIZE; 1956 sargs.serinfo = &smeta; 1957 hargs.request = RTLD_DI_SERINFOSIZE; 1958 hargs.serinfo = &hmeta; 1959 1960 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1961 &sargs); 1962 path_enumerate(hints, fill_search_info, NULL, &hargs); 1963 1964 SLPinfo = xmalloc(smeta.dls_size); 1965 hintinfo = xmalloc(hmeta.dls_size); 1966 1967 /* 1968 * Next fetch both sets of paths. 1969 */ 1970 sargs.request = RTLD_DI_SERINFO; 1971 sargs.serinfo = SLPinfo; 1972 sargs.serpath = &SLPinfo->dls_serpath[0]; 1973 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1974 1975 hargs.request = RTLD_DI_SERINFO; 1976 hargs.serinfo = hintinfo; 1977 hargs.serpath = &hintinfo->dls_serpath[0]; 1978 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1979 1980 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1981 &sargs); 1982 path_enumerate(hints, fill_search_info, NULL, &hargs); 1983 1984 /* 1985 * Now calculate the difference between two sets, by excluding 1986 * standard paths from the full set. 1987 */ 1988 fndx = 0; 1989 fcount = 0; 1990 filtered_path = xmalloc(hdr.dirlistlen + 1); 1991 hintpath = &hintinfo->dls_serpath[0]; 1992 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1993 skip = false; 1994 SLPpath = &SLPinfo->dls_serpath[0]; 1995 /* 1996 * Check each standard path against current. 1997 */ 1998 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1999 /* matched, skip the path */ 2000 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2001 skip = true; 2002 break; 2003 } 2004 } 2005 if (skip) 2006 continue; 2007 /* 2008 * Not matched against any standard path, add the path 2009 * to result. Separate consequtive paths with ':'. 2010 */ 2011 if (fcount > 0) { 2012 filtered_path[fndx] = ':'; 2013 fndx++; 2014 } 2015 fcount++; 2016 flen = strlen(hintpath->dls_name); 2017 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2018 fndx += flen; 2019 } 2020 filtered_path[fndx] = '\0'; 2021 2022 free(SLPinfo); 2023 free(hintinfo); 2024 2025 filt_ret: 2026 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2027 } 2028 2029 static void 2030 init_dag(Obj_Entry *root) 2031 { 2032 const Needed_Entry *needed; 2033 const Objlist_Entry *elm; 2034 DoneList donelist; 2035 2036 if (root->dag_inited) 2037 return; 2038 donelist_init(&donelist); 2039 2040 /* Root object belongs to own DAG. */ 2041 objlist_push_tail(&root->dldags, root); 2042 objlist_push_tail(&root->dagmembers, root); 2043 donelist_check(&donelist, root); 2044 2045 /* 2046 * Add dependencies of root object to DAG in breadth order 2047 * by exploiting the fact that each new object get added 2048 * to the tail of the dagmembers list. 2049 */ 2050 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2051 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2052 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2053 continue; 2054 objlist_push_tail(&needed->obj->dldags, root); 2055 objlist_push_tail(&root->dagmembers, needed->obj); 2056 } 2057 } 2058 root->dag_inited = true; 2059 } 2060 2061 static void 2062 init_marker(Obj_Entry *marker) 2063 { 2064 2065 bzero(marker, sizeof(*marker)); 2066 marker->marker = true; 2067 } 2068 2069 Obj_Entry * 2070 globallist_curr(const Obj_Entry *obj) 2071 { 2072 2073 for (;;) { 2074 if (obj == NULL) 2075 return (NULL); 2076 if (!obj->marker) 2077 return (__DECONST(Obj_Entry *, obj)); 2078 obj = TAILQ_PREV(obj, obj_entry_q, next); 2079 } 2080 } 2081 2082 Obj_Entry * 2083 globallist_next(const Obj_Entry *obj) 2084 { 2085 2086 for (;;) { 2087 obj = TAILQ_NEXT(obj, next); 2088 if (obj == NULL) 2089 return (NULL); 2090 if (!obj->marker) 2091 return (__DECONST(Obj_Entry *, obj)); 2092 } 2093 } 2094 2095 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2096 static void 2097 hold_object(Obj_Entry *obj) 2098 { 2099 2100 obj->holdcount++; 2101 } 2102 2103 static void 2104 unhold_object(Obj_Entry *obj) 2105 { 2106 2107 assert(obj->holdcount > 0); 2108 if (--obj->holdcount == 0 && obj->unholdfree) 2109 release_object(obj); 2110 } 2111 2112 static void 2113 process_z(Obj_Entry *root) 2114 { 2115 const Objlist_Entry *elm; 2116 Obj_Entry *obj; 2117 2118 /* 2119 * Walk over object DAG and process every dependent object 2120 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2121 * to grow their own DAG. 2122 * 2123 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2124 * symlook_global() to work. 2125 * 2126 * For DF_1_NODELETE, the DAG should have its reference upped. 2127 */ 2128 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2129 obj = elm->obj; 2130 if (obj == NULL) 2131 continue; 2132 if (obj->z_nodelete && !obj->ref_nodel) { 2133 dbg("obj %s -z nodelete", obj->path); 2134 init_dag(obj); 2135 ref_dag(obj); 2136 obj->ref_nodel = true; 2137 } 2138 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2139 dbg("obj %s -z global", obj->path); 2140 objlist_push_tail(&list_global, obj); 2141 init_dag(obj); 2142 } 2143 } 2144 } 2145 /* 2146 * Initialize the dynamic linker. The argument is the address at which 2147 * the dynamic linker has been mapped into memory. The primary task of 2148 * this function is to relocate the dynamic linker. 2149 */ 2150 static void 2151 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2152 { 2153 Obj_Entry objtmp; /* Temporary rtld object */ 2154 const Elf_Ehdr *ehdr; 2155 const Elf_Dyn *dyn_rpath; 2156 const Elf_Dyn *dyn_soname; 2157 const Elf_Dyn *dyn_runpath; 2158 2159 #ifdef RTLD_INIT_PAGESIZES_EARLY 2160 /* The page size is required by the dynamic memory allocator. */ 2161 init_pagesizes(aux_info); 2162 #endif 2163 2164 /* 2165 * Conjure up an Obj_Entry structure for the dynamic linker. 2166 * 2167 * The "path" member can't be initialized yet because string constants 2168 * cannot yet be accessed. Below we will set it correctly. 2169 */ 2170 memset(&objtmp, 0, sizeof(objtmp)); 2171 objtmp.path = NULL; 2172 objtmp.rtld = true; 2173 objtmp.mapbase = mapbase; 2174 #ifdef PIC 2175 objtmp.relocbase = mapbase; 2176 #endif 2177 2178 objtmp.dynamic = rtld_dynamic(&objtmp); 2179 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2180 assert(objtmp.needed == NULL); 2181 #if !defined(__mips__) 2182 /* MIPS has a bogus DT_TEXTREL. */ 2183 assert(!objtmp.textrel); 2184 #endif 2185 /* 2186 * Temporarily put the dynamic linker entry into the object list, so 2187 * that symbols can be found. 2188 */ 2189 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2190 2191 ehdr = (Elf_Ehdr *)mapbase; 2192 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2193 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2194 2195 /* Initialize the object list. */ 2196 TAILQ_INIT(&obj_list); 2197 2198 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2199 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2200 2201 #ifndef RTLD_INIT_PAGESIZES_EARLY 2202 /* The page size is required by the dynamic memory allocator. */ 2203 init_pagesizes(aux_info); 2204 #endif 2205 2206 if (aux_info[AT_OSRELDATE] != NULL) 2207 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2208 2209 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2210 2211 /* Replace the path with a dynamically allocated copy. */ 2212 obj_rtld.path = xstrdup(ld_path_rtld); 2213 2214 r_debug.r_brk = r_debug_state; 2215 r_debug.r_state = RT_CONSISTENT; 2216 } 2217 2218 /* 2219 * Retrieve the array of supported page sizes. The kernel provides the page 2220 * sizes in increasing order. 2221 */ 2222 static void 2223 init_pagesizes(Elf_Auxinfo **aux_info) 2224 { 2225 static size_t psa[MAXPAGESIZES]; 2226 int mib[2]; 2227 size_t len, size; 2228 2229 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2230 NULL) { 2231 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2232 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2233 } else { 2234 len = 2; 2235 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2236 size = sizeof(psa); 2237 else { 2238 /* As a fallback, retrieve the base page size. */ 2239 size = sizeof(psa[0]); 2240 if (aux_info[AT_PAGESZ] != NULL) { 2241 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2242 goto psa_filled; 2243 } else { 2244 mib[0] = CTL_HW; 2245 mib[1] = HW_PAGESIZE; 2246 len = 2; 2247 } 2248 } 2249 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2250 _rtld_error("sysctl for hw.pagesize(s) failed"); 2251 rtld_die(); 2252 } 2253 psa_filled: 2254 pagesizes = psa; 2255 } 2256 npagesizes = size / sizeof(pagesizes[0]); 2257 /* Discard any invalid entries at the end of the array. */ 2258 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2259 npagesizes--; 2260 } 2261 2262 /* 2263 * Add the init functions from a needed object list (and its recursive 2264 * needed objects) to "list". This is not used directly; it is a helper 2265 * function for initlist_add_objects(). The write lock must be held 2266 * when this function is called. 2267 */ 2268 static void 2269 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2270 { 2271 /* Recursively process the successor needed objects. */ 2272 if (needed->next != NULL) 2273 initlist_add_neededs(needed->next, list); 2274 2275 /* Process the current needed object. */ 2276 if (needed->obj != NULL) 2277 initlist_add_objects(needed->obj, needed->obj, list); 2278 } 2279 2280 /* 2281 * Scan all of the DAGs rooted in the range of objects from "obj" to 2282 * "tail" and add their init functions to "list". This recurses over 2283 * the DAGs and ensure the proper init ordering such that each object's 2284 * needed libraries are initialized before the object itself. At the 2285 * same time, this function adds the objects to the global finalization 2286 * list "list_fini" in the opposite order. The write lock must be 2287 * held when this function is called. 2288 */ 2289 static void 2290 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2291 { 2292 Obj_Entry *nobj; 2293 2294 if (obj->init_scanned || obj->init_done) 2295 return; 2296 obj->init_scanned = true; 2297 2298 /* Recursively process the successor objects. */ 2299 nobj = globallist_next(obj); 2300 if (nobj != NULL && obj != tail) 2301 initlist_add_objects(nobj, tail, list); 2302 2303 /* Recursively process the needed objects. */ 2304 if (obj->needed != NULL) 2305 initlist_add_neededs(obj->needed, list); 2306 if (obj->needed_filtees != NULL) 2307 initlist_add_neededs(obj->needed_filtees, list); 2308 if (obj->needed_aux_filtees != NULL) 2309 initlist_add_neededs(obj->needed_aux_filtees, list); 2310 2311 /* Add the object to the init list. */ 2312 objlist_push_tail(list, obj); 2313 2314 /* Add the object to the global fini list in the reverse order. */ 2315 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2316 && !obj->on_fini_list) { 2317 objlist_push_head(&list_fini, obj); 2318 obj->on_fini_list = true; 2319 } 2320 } 2321 2322 #ifndef FPTR_TARGET 2323 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2324 #endif 2325 2326 static void 2327 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2328 { 2329 Needed_Entry *needed, *needed1; 2330 2331 for (needed = n; needed != NULL; needed = needed->next) { 2332 if (needed->obj != NULL) { 2333 dlclose_locked(needed->obj, lockstate); 2334 needed->obj = NULL; 2335 } 2336 } 2337 for (needed = n; needed != NULL; needed = needed1) { 2338 needed1 = needed->next; 2339 free(needed); 2340 } 2341 } 2342 2343 static void 2344 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2345 { 2346 2347 free_needed_filtees(obj->needed_filtees, lockstate); 2348 obj->needed_filtees = NULL; 2349 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2350 obj->needed_aux_filtees = NULL; 2351 obj->filtees_loaded = false; 2352 } 2353 2354 static void 2355 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2356 RtldLockState *lockstate) 2357 { 2358 2359 for (; needed != NULL; needed = needed->next) { 2360 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2361 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2362 RTLD_LOCAL, lockstate); 2363 } 2364 } 2365 2366 static void 2367 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2368 { 2369 2370 lock_restart_for_upgrade(lockstate); 2371 if (!obj->filtees_loaded) { 2372 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2373 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2374 obj->filtees_loaded = true; 2375 } 2376 } 2377 2378 static int 2379 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2380 { 2381 Obj_Entry *obj1; 2382 2383 for (; needed != NULL; needed = needed->next) { 2384 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2385 flags & ~RTLD_LO_NOLOAD); 2386 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2387 return (-1); 2388 } 2389 return (0); 2390 } 2391 2392 /* 2393 * Given a shared object, traverse its list of needed objects, and load 2394 * each of them. Returns 0 on success. Generates an error message and 2395 * returns -1 on failure. 2396 */ 2397 static int 2398 load_needed_objects(Obj_Entry *first, int flags) 2399 { 2400 Obj_Entry *obj; 2401 2402 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2403 if (obj->marker) 2404 continue; 2405 if (process_needed(obj, obj->needed, flags) == -1) 2406 return (-1); 2407 } 2408 return (0); 2409 } 2410 2411 static int 2412 load_preload_objects(void) 2413 { 2414 char *p = ld_preload; 2415 Obj_Entry *obj; 2416 static const char delim[] = " \t:;"; 2417 2418 if (p == NULL) 2419 return 0; 2420 2421 p += strspn(p, delim); 2422 while (*p != '\0') { 2423 size_t len = strcspn(p, delim); 2424 char savech; 2425 2426 savech = p[len]; 2427 p[len] = '\0'; 2428 obj = load_object(p, -1, NULL, 0); 2429 if (obj == NULL) 2430 return -1; /* XXX - cleanup */ 2431 obj->z_interpose = true; 2432 p[len] = savech; 2433 p += len; 2434 p += strspn(p, delim); 2435 } 2436 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2437 return 0; 2438 } 2439 2440 static const char * 2441 printable_path(const char *path) 2442 { 2443 2444 return (path == NULL ? "<unknown>" : path); 2445 } 2446 2447 /* 2448 * Load a shared object into memory, if it is not already loaded. The 2449 * object may be specified by name or by user-supplied file descriptor 2450 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2451 * duplicate is. 2452 * 2453 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2454 * on failure. 2455 */ 2456 static Obj_Entry * 2457 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2458 { 2459 Obj_Entry *obj; 2460 int fd; 2461 struct stat sb; 2462 char *path; 2463 2464 fd = -1; 2465 if (name != NULL) { 2466 TAILQ_FOREACH(obj, &obj_list, next) { 2467 if (obj->marker || obj->doomed) 2468 continue; 2469 if (object_match_name(obj, name)) 2470 return (obj); 2471 } 2472 2473 path = find_library(name, refobj, &fd); 2474 if (path == NULL) 2475 return (NULL); 2476 } else 2477 path = NULL; 2478 2479 if (fd >= 0) { 2480 /* 2481 * search_library_pathfds() opens a fresh file descriptor for the 2482 * library, so there is no need to dup(). 2483 */ 2484 } else if (fd_u == -1) { 2485 /* 2486 * If we didn't find a match by pathname, or the name is not 2487 * supplied, open the file and check again by device and inode. 2488 * This avoids false mismatches caused by multiple links or ".." 2489 * in pathnames. 2490 * 2491 * To avoid a race, we open the file and use fstat() rather than 2492 * using stat(). 2493 */ 2494 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2495 _rtld_error("Cannot open \"%s\"", path); 2496 free(path); 2497 return (NULL); 2498 } 2499 } else { 2500 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2501 if (fd == -1) { 2502 _rtld_error("Cannot dup fd"); 2503 free(path); 2504 return (NULL); 2505 } 2506 } 2507 if (fstat(fd, &sb) == -1) { 2508 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2509 close(fd); 2510 free(path); 2511 return NULL; 2512 } 2513 TAILQ_FOREACH(obj, &obj_list, next) { 2514 if (obj->marker || obj->doomed) 2515 continue; 2516 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2517 break; 2518 } 2519 if (obj != NULL && name != NULL) { 2520 object_add_name(obj, name); 2521 free(path); 2522 close(fd); 2523 return obj; 2524 } 2525 if (flags & RTLD_LO_NOLOAD) { 2526 free(path); 2527 close(fd); 2528 return (NULL); 2529 } 2530 2531 /* First use of this object, so we must map it in */ 2532 obj = do_load_object(fd, name, path, &sb, flags); 2533 if (obj == NULL) 2534 free(path); 2535 close(fd); 2536 2537 return obj; 2538 } 2539 2540 static Obj_Entry * 2541 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2542 int flags) 2543 { 2544 Obj_Entry *obj; 2545 struct statfs fs; 2546 2547 /* 2548 * but first, make sure that environment variables haven't been 2549 * used to circumvent the noexec flag on a filesystem. 2550 */ 2551 if (dangerous_ld_env) { 2552 if (fstatfs(fd, &fs) != 0) { 2553 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2554 return NULL; 2555 } 2556 if (fs.f_flags & MNT_NOEXEC) { 2557 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2558 return NULL; 2559 } 2560 } 2561 dbg("loading \"%s\"", printable_path(path)); 2562 obj = map_object(fd, printable_path(path), sbp); 2563 if (obj == NULL) 2564 return NULL; 2565 2566 /* 2567 * If DT_SONAME is present in the object, digest_dynamic2 already 2568 * added it to the object names. 2569 */ 2570 if (name != NULL) 2571 object_add_name(obj, name); 2572 obj->path = path; 2573 if (!digest_dynamic(obj, 0)) 2574 goto errp; 2575 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2576 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2577 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2578 RTLD_LO_DLOPEN) { 2579 dbg("refusing to load non-loadable \"%s\"", obj->path); 2580 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2581 goto errp; 2582 } 2583 2584 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2585 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2586 obj_count++; 2587 obj_loads++; 2588 linkmap_add(obj); /* for GDB & dlinfo() */ 2589 max_stack_flags |= obj->stack_flags; 2590 2591 dbg(" %p .. %p: %s", obj->mapbase, 2592 obj->mapbase + obj->mapsize - 1, obj->path); 2593 if (obj->textrel) 2594 dbg(" WARNING: %s has impure text", obj->path); 2595 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2596 obj->path); 2597 2598 return (obj); 2599 2600 errp: 2601 munmap(obj->mapbase, obj->mapsize); 2602 obj_free(obj); 2603 return (NULL); 2604 } 2605 2606 static Obj_Entry * 2607 obj_from_addr(const void *addr) 2608 { 2609 Obj_Entry *obj; 2610 2611 TAILQ_FOREACH(obj, &obj_list, next) { 2612 if (obj->marker) 2613 continue; 2614 if (addr < (void *) obj->mapbase) 2615 continue; 2616 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2617 return obj; 2618 } 2619 return NULL; 2620 } 2621 2622 static void 2623 preinit_main(void) 2624 { 2625 Elf_Addr *preinit_addr; 2626 int index; 2627 2628 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2629 if (preinit_addr == NULL) 2630 return; 2631 2632 for (index = 0; index < obj_main->preinit_array_num; index++) { 2633 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2634 dbg("calling preinit function for %s at %p", obj_main->path, 2635 (void *)preinit_addr[index]); 2636 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2637 0, 0, obj_main->path); 2638 call_init_pointer(obj_main, preinit_addr[index]); 2639 } 2640 } 2641 } 2642 2643 /* 2644 * Call the finalization functions for each of the objects in "list" 2645 * belonging to the DAG of "root" and referenced once. If NULL "root" 2646 * is specified, every finalization function will be called regardless 2647 * of the reference count and the list elements won't be freed. All of 2648 * the objects are expected to have non-NULL fini functions. 2649 */ 2650 static void 2651 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2652 { 2653 Objlist_Entry *elm; 2654 char *saved_msg; 2655 Elf_Addr *fini_addr; 2656 int index; 2657 2658 assert(root == NULL || root->refcount == 1); 2659 2660 if (root != NULL) 2661 root->doomed = true; 2662 2663 /* 2664 * Preserve the current error message since a fini function might 2665 * call into the dynamic linker and overwrite it. 2666 */ 2667 saved_msg = errmsg_save(); 2668 do { 2669 STAILQ_FOREACH(elm, list, link) { 2670 if (root != NULL && (elm->obj->refcount != 1 || 2671 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2672 continue; 2673 /* Remove object from fini list to prevent recursive invocation. */ 2674 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2675 /* Ensure that new references cannot be acquired. */ 2676 elm->obj->doomed = true; 2677 2678 hold_object(elm->obj); 2679 lock_release(rtld_bind_lock, lockstate); 2680 /* 2681 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2682 * When this happens, DT_FINI_ARRAY is processed first. 2683 */ 2684 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2685 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2686 for (index = elm->obj->fini_array_num - 1; index >= 0; 2687 index--) { 2688 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2689 dbg("calling fini function for %s at %p", 2690 elm->obj->path, (void *)fini_addr[index]); 2691 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2692 (void *)fini_addr[index], 0, 0, elm->obj->path); 2693 call_initfini_pointer(elm->obj, fini_addr[index]); 2694 } 2695 } 2696 } 2697 if (elm->obj->fini != (Elf_Addr)NULL) { 2698 dbg("calling fini function for %s at %p", elm->obj->path, 2699 (void *)elm->obj->fini); 2700 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2701 0, 0, elm->obj->path); 2702 call_initfini_pointer(elm->obj, elm->obj->fini); 2703 } 2704 wlock_acquire(rtld_bind_lock, lockstate); 2705 unhold_object(elm->obj); 2706 /* No need to free anything if process is going down. */ 2707 if (root != NULL) 2708 free(elm); 2709 /* 2710 * We must restart the list traversal after every fini call 2711 * because a dlclose() call from the fini function or from 2712 * another thread might have modified the reference counts. 2713 */ 2714 break; 2715 } 2716 } while (elm != NULL); 2717 errmsg_restore(saved_msg); 2718 } 2719 2720 /* 2721 * Call the initialization functions for each of the objects in 2722 * "list". All of the objects are expected to have non-NULL init 2723 * functions. 2724 */ 2725 static void 2726 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2727 { 2728 Objlist_Entry *elm; 2729 Obj_Entry *obj; 2730 char *saved_msg; 2731 Elf_Addr *init_addr; 2732 void (*reg)(void (*)(void)); 2733 int index; 2734 2735 /* 2736 * Clean init_scanned flag so that objects can be rechecked and 2737 * possibly initialized earlier if any of vectors called below 2738 * cause the change by using dlopen. 2739 */ 2740 TAILQ_FOREACH(obj, &obj_list, next) { 2741 if (obj->marker) 2742 continue; 2743 obj->init_scanned = false; 2744 } 2745 2746 /* 2747 * Preserve the current error message since an init function might 2748 * call into the dynamic linker and overwrite it. 2749 */ 2750 saved_msg = errmsg_save(); 2751 STAILQ_FOREACH(elm, list, link) { 2752 if (elm->obj->init_done) /* Initialized early. */ 2753 continue; 2754 /* 2755 * Race: other thread might try to use this object before current 2756 * one completes the initialization. Not much can be done here 2757 * without better locking. 2758 */ 2759 elm->obj->init_done = true; 2760 hold_object(elm->obj); 2761 reg = NULL; 2762 if (elm->obj == obj_main && obj_main->crt_no_init) { 2763 reg = (void (*)(void (*)(void)))get_program_var_addr( 2764 "__libc_atexit", lockstate); 2765 } 2766 lock_release(rtld_bind_lock, lockstate); 2767 if (reg != NULL) { 2768 reg(rtld_exit); 2769 rtld_exit_ptr = rtld_nop_exit; 2770 } 2771 2772 /* 2773 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2774 * When this happens, DT_INIT is processed first. 2775 */ 2776 if (elm->obj->init != (Elf_Addr)NULL) { 2777 dbg("calling init function for %s at %p", elm->obj->path, 2778 (void *)elm->obj->init); 2779 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2780 0, 0, elm->obj->path); 2781 call_initfini_pointer(elm->obj, elm->obj->init); 2782 } 2783 init_addr = (Elf_Addr *)elm->obj->init_array; 2784 if (init_addr != NULL) { 2785 for (index = 0; index < elm->obj->init_array_num; index++) { 2786 if (init_addr[index] != 0 && init_addr[index] != 1) { 2787 dbg("calling init function for %s at %p", elm->obj->path, 2788 (void *)init_addr[index]); 2789 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2790 (void *)init_addr[index], 0, 0, elm->obj->path); 2791 call_init_pointer(elm->obj, init_addr[index]); 2792 } 2793 } 2794 } 2795 wlock_acquire(rtld_bind_lock, lockstate); 2796 unhold_object(elm->obj); 2797 } 2798 errmsg_restore(saved_msg); 2799 } 2800 2801 static void 2802 objlist_clear(Objlist *list) 2803 { 2804 Objlist_Entry *elm; 2805 2806 while (!STAILQ_EMPTY(list)) { 2807 elm = STAILQ_FIRST(list); 2808 STAILQ_REMOVE_HEAD(list, link); 2809 free(elm); 2810 } 2811 } 2812 2813 static Objlist_Entry * 2814 objlist_find(Objlist *list, const Obj_Entry *obj) 2815 { 2816 Objlist_Entry *elm; 2817 2818 STAILQ_FOREACH(elm, list, link) 2819 if (elm->obj == obj) 2820 return elm; 2821 return NULL; 2822 } 2823 2824 static void 2825 objlist_init(Objlist *list) 2826 { 2827 STAILQ_INIT(list); 2828 } 2829 2830 static void 2831 objlist_push_head(Objlist *list, Obj_Entry *obj) 2832 { 2833 Objlist_Entry *elm; 2834 2835 elm = NEW(Objlist_Entry); 2836 elm->obj = obj; 2837 STAILQ_INSERT_HEAD(list, elm, link); 2838 } 2839 2840 static void 2841 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2842 { 2843 Objlist_Entry *elm; 2844 2845 elm = NEW(Objlist_Entry); 2846 elm->obj = obj; 2847 STAILQ_INSERT_TAIL(list, elm, link); 2848 } 2849 2850 static void 2851 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2852 { 2853 Objlist_Entry *elm, *listelm; 2854 2855 STAILQ_FOREACH(listelm, list, link) { 2856 if (listelm->obj == listobj) 2857 break; 2858 } 2859 elm = NEW(Objlist_Entry); 2860 elm->obj = obj; 2861 if (listelm != NULL) 2862 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2863 else 2864 STAILQ_INSERT_TAIL(list, elm, link); 2865 } 2866 2867 static void 2868 objlist_remove(Objlist *list, Obj_Entry *obj) 2869 { 2870 Objlist_Entry *elm; 2871 2872 if ((elm = objlist_find(list, obj)) != NULL) { 2873 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2874 free(elm); 2875 } 2876 } 2877 2878 /* 2879 * Relocate dag rooted in the specified object. 2880 * Returns 0 on success, or -1 on failure. 2881 */ 2882 2883 static int 2884 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2885 int flags, RtldLockState *lockstate) 2886 { 2887 Objlist_Entry *elm; 2888 int error; 2889 2890 error = 0; 2891 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2892 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2893 lockstate); 2894 if (error == -1) 2895 break; 2896 } 2897 return (error); 2898 } 2899 2900 /* 2901 * Prepare for, or clean after, relocating an object marked with 2902 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2903 * segments are remapped read-write. After relocations are done, the 2904 * segment's permissions are returned back to the modes specified in 2905 * the phdrs. If any relocation happened, or always for wired 2906 * program, COW is triggered. 2907 */ 2908 static int 2909 reloc_textrel_prot(Obj_Entry *obj, bool before) 2910 { 2911 const Elf_Phdr *ph; 2912 void *base; 2913 size_t l, sz; 2914 int prot; 2915 2916 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2917 l--, ph++) { 2918 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2919 continue; 2920 base = obj->relocbase + trunc_page(ph->p_vaddr); 2921 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2922 trunc_page(ph->p_vaddr); 2923 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2924 if (mprotect(base, sz, prot) == -1) { 2925 _rtld_error("%s: Cannot write-%sable text segment: %s", 2926 obj->path, before ? "en" : "dis", 2927 rtld_strerror(errno)); 2928 return (-1); 2929 } 2930 } 2931 return (0); 2932 } 2933 2934 /* 2935 * Relocate single object. 2936 * Returns 0 on success, or -1 on failure. 2937 */ 2938 static int 2939 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2940 int flags, RtldLockState *lockstate) 2941 { 2942 2943 if (obj->relocated) 2944 return (0); 2945 obj->relocated = true; 2946 if (obj != rtldobj) 2947 dbg("relocating \"%s\"", obj->path); 2948 2949 if (obj->symtab == NULL || obj->strtab == NULL || 2950 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2951 _rtld_error("%s: Shared object has no run-time symbol table", 2952 obj->path); 2953 return (-1); 2954 } 2955 2956 /* There are relocations to the write-protected text segment. */ 2957 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2958 return (-1); 2959 2960 /* Process the non-PLT non-IFUNC relocations. */ 2961 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2962 return (-1); 2963 2964 /* Re-protected the text segment. */ 2965 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2966 return (-1); 2967 2968 /* Set the special PLT or GOT entries. */ 2969 init_pltgot(obj); 2970 2971 /* Process the PLT relocations. */ 2972 if (reloc_plt(obj, flags, lockstate) == -1) 2973 return (-1); 2974 /* Relocate the jump slots if we are doing immediate binding. */ 2975 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2976 lockstate) == -1) 2977 return (-1); 2978 2979 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2980 return (-1); 2981 2982 /* 2983 * Set up the magic number and version in the Obj_Entry. These 2984 * were checked in the crt1.o from the original ElfKit, so we 2985 * set them for backward compatibility. 2986 */ 2987 obj->magic = RTLD_MAGIC; 2988 obj->version = RTLD_VERSION; 2989 2990 return (0); 2991 } 2992 2993 /* 2994 * Relocate newly-loaded shared objects. The argument is a pointer to 2995 * the Obj_Entry for the first such object. All objects from the first 2996 * to the end of the list of objects are relocated. Returns 0 on success, 2997 * or -1 on failure. 2998 */ 2999 static int 3000 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3001 int flags, RtldLockState *lockstate) 3002 { 3003 Obj_Entry *obj; 3004 int error; 3005 3006 for (error = 0, obj = first; obj != NULL; 3007 obj = TAILQ_NEXT(obj, next)) { 3008 if (obj->marker) 3009 continue; 3010 error = relocate_object(obj, bind_now, rtldobj, flags, 3011 lockstate); 3012 if (error == -1) 3013 break; 3014 } 3015 return (error); 3016 } 3017 3018 /* 3019 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3020 * referencing STT_GNU_IFUNC symbols is postponed till the other 3021 * relocations are done. The indirect functions specified as 3022 * ifunc are allowed to call other symbols, so we need to have 3023 * objects relocated before asking for resolution from indirects. 3024 * 3025 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3026 * instead of the usual lazy handling of PLT slots. It is 3027 * consistent with how GNU does it. 3028 */ 3029 static int 3030 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3031 RtldLockState *lockstate) 3032 { 3033 3034 if (obj->ifuncs_resolved) 3035 return (0); 3036 obj->ifuncs_resolved = true; 3037 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3038 return (0); 3039 if (obj_disable_relro(obj) == -1 || 3040 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3041 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3042 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3043 obj_enforce_relro(obj) == -1) 3044 return (-1); 3045 return (0); 3046 } 3047 3048 static int 3049 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3050 RtldLockState *lockstate) 3051 { 3052 Objlist_Entry *elm; 3053 Obj_Entry *obj; 3054 3055 STAILQ_FOREACH(elm, list, link) { 3056 obj = elm->obj; 3057 if (obj->marker) 3058 continue; 3059 if (resolve_object_ifunc(obj, bind_now, flags, 3060 lockstate) == -1) 3061 return (-1); 3062 } 3063 return (0); 3064 } 3065 3066 /* 3067 * Cleanup procedure. It will be called (by the atexit mechanism) just 3068 * before the process exits. 3069 */ 3070 static void 3071 rtld_exit(void) 3072 { 3073 RtldLockState lockstate; 3074 3075 wlock_acquire(rtld_bind_lock, &lockstate); 3076 dbg("rtld_exit()"); 3077 objlist_call_fini(&list_fini, NULL, &lockstate); 3078 /* No need to remove the items from the list, since we are exiting. */ 3079 if (!libmap_disable) 3080 lm_fini(); 3081 lock_release(rtld_bind_lock, &lockstate); 3082 } 3083 3084 static void 3085 rtld_nop_exit(void) 3086 { 3087 } 3088 3089 /* 3090 * Iterate over a search path, translate each element, and invoke the 3091 * callback on the result. 3092 */ 3093 static void * 3094 path_enumerate(const char *path, path_enum_proc callback, 3095 const char *refobj_path, void *arg) 3096 { 3097 const char *trans; 3098 if (path == NULL) 3099 return (NULL); 3100 3101 path += strspn(path, ":;"); 3102 while (*path != '\0') { 3103 size_t len; 3104 char *res; 3105 3106 len = strcspn(path, ":;"); 3107 trans = lm_findn(refobj_path, path, len); 3108 if (trans) 3109 res = callback(trans, strlen(trans), arg); 3110 else 3111 res = callback(path, len, arg); 3112 3113 if (res != NULL) 3114 return (res); 3115 3116 path += len; 3117 path += strspn(path, ":;"); 3118 } 3119 3120 return (NULL); 3121 } 3122 3123 struct try_library_args { 3124 const char *name; 3125 size_t namelen; 3126 char *buffer; 3127 size_t buflen; 3128 int fd; 3129 }; 3130 3131 static void * 3132 try_library_path(const char *dir, size_t dirlen, void *param) 3133 { 3134 struct try_library_args *arg; 3135 int fd; 3136 3137 arg = param; 3138 if (*dir == '/' || trust) { 3139 char *pathname; 3140 3141 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3142 return (NULL); 3143 3144 pathname = arg->buffer; 3145 strncpy(pathname, dir, dirlen); 3146 pathname[dirlen] = '/'; 3147 strcpy(pathname + dirlen + 1, arg->name); 3148 3149 dbg(" Trying \"%s\"", pathname); 3150 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3151 if (fd >= 0) { 3152 dbg(" Opened \"%s\", fd %d", pathname, fd); 3153 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3154 strcpy(pathname, arg->buffer); 3155 arg->fd = fd; 3156 return (pathname); 3157 } else { 3158 dbg(" Failed to open \"%s\": %s", 3159 pathname, rtld_strerror(errno)); 3160 } 3161 } 3162 return (NULL); 3163 } 3164 3165 static char * 3166 search_library_path(const char *name, const char *path, 3167 const char *refobj_path, int *fdp) 3168 { 3169 char *p; 3170 struct try_library_args arg; 3171 3172 if (path == NULL) 3173 return NULL; 3174 3175 arg.name = name; 3176 arg.namelen = strlen(name); 3177 arg.buffer = xmalloc(PATH_MAX); 3178 arg.buflen = PATH_MAX; 3179 arg.fd = -1; 3180 3181 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3182 *fdp = arg.fd; 3183 3184 free(arg.buffer); 3185 3186 return (p); 3187 } 3188 3189 3190 /* 3191 * Finds the library with the given name using the directory descriptors 3192 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3193 * 3194 * Returns a freshly-opened close-on-exec file descriptor for the library, 3195 * or -1 if the library cannot be found. 3196 */ 3197 static char * 3198 search_library_pathfds(const char *name, const char *path, int *fdp) 3199 { 3200 char *envcopy, *fdstr, *found, *last_token; 3201 size_t len; 3202 int dirfd, fd; 3203 3204 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3205 3206 /* Don't load from user-specified libdirs into setuid binaries. */ 3207 if (!trust) 3208 return (NULL); 3209 3210 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3211 if (path == NULL) 3212 return (NULL); 3213 3214 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3215 if (name[0] == '/') { 3216 dbg("Absolute path (%s) passed to %s", name, __func__); 3217 return (NULL); 3218 } 3219 3220 /* 3221 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3222 * copy of the path, as strtok_r rewrites separator tokens 3223 * with '\0'. 3224 */ 3225 found = NULL; 3226 envcopy = xstrdup(path); 3227 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3228 fdstr = strtok_r(NULL, ":", &last_token)) { 3229 dirfd = parse_integer(fdstr); 3230 if (dirfd < 0) { 3231 _rtld_error("failed to parse directory FD: '%s'", 3232 fdstr); 3233 break; 3234 } 3235 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3236 if (fd >= 0) { 3237 *fdp = fd; 3238 len = strlen(fdstr) + strlen(name) + 3; 3239 found = xmalloc(len); 3240 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3241 _rtld_error("error generating '%d/%s'", 3242 dirfd, name); 3243 rtld_die(); 3244 } 3245 dbg("open('%s') => %d", found, fd); 3246 break; 3247 } 3248 } 3249 free(envcopy); 3250 3251 return (found); 3252 } 3253 3254 3255 int 3256 dlclose(void *handle) 3257 { 3258 RtldLockState lockstate; 3259 int error; 3260 3261 wlock_acquire(rtld_bind_lock, &lockstate); 3262 error = dlclose_locked(handle, &lockstate); 3263 lock_release(rtld_bind_lock, &lockstate); 3264 return (error); 3265 } 3266 3267 static int 3268 dlclose_locked(void *handle, RtldLockState *lockstate) 3269 { 3270 Obj_Entry *root; 3271 3272 root = dlcheck(handle); 3273 if (root == NULL) 3274 return -1; 3275 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3276 root->path); 3277 3278 /* Unreference the object and its dependencies. */ 3279 root->dl_refcount--; 3280 3281 if (root->refcount == 1) { 3282 /* 3283 * The object will be no longer referenced, so we must unload it. 3284 * First, call the fini functions. 3285 */ 3286 objlist_call_fini(&list_fini, root, lockstate); 3287 3288 unref_dag(root); 3289 3290 /* Finish cleaning up the newly-unreferenced objects. */ 3291 GDB_STATE(RT_DELETE,&root->linkmap); 3292 unload_object(root, lockstate); 3293 GDB_STATE(RT_CONSISTENT,NULL); 3294 } else 3295 unref_dag(root); 3296 3297 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3298 return 0; 3299 } 3300 3301 char * 3302 dlerror(void) 3303 { 3304 char *msg = error_message; 3305 error_message = NULL; 3306 return msg; 3307 } 3308 3309 /* 3310 * This function is deprecated and has no effect. 3311 */ 3312 void 3313 dllockinit(void *context, 3314 void *(*_lock_create)(void *context) __unused, 3315 void (*_rlock_acquire)(void *lock) __unused, 3316 void (*_wlock_acquire)(void *lock) __unused, 3317 void (*_lock_release)(void *lock) __unused, 3318 void (*_lock_destroy)(void *lock) __unused, 3319 void (*context_destroy)(void *context)) 3320 { 3321 static void *cur_context; 3322 static void (*cur_context_destroy)(void *); 3323 3324 /* Just destroy the context from the previous call, if necessary. */ 3325 if (cur_context_destroy != NULL) 3326 cur_context_destroy(cur_context); 3327 cur_context = context; 3328 cur_context_destroy = context_destroy; 3329 } 3330 3331 void * 3332 dlopen(const char *name, int mode) 3333 { 3334 3335 return (rtld_dlopen(name, -1, mode)); 3336 } 3337 3338 void * 3339 fdlopen(int fd, int mode) 3340 { 3341 3342 return (rtld_dlopen(NULL, fd, mode)); 3343 } 3344 3345 static void * 3346 rtld_dlopen(const char *name, int fd, int mode) 3347 { 3348 RtldLockState lockstate; 3349 int lo_flags; 3350 3351 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3352 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3353 if (ld_tracing != NULL) { 3354 rlock_acquire(rtld_bind_lock, &lockstate); 3355 if (sigsetjmp(lockstate.env, 0) != 0) 3356 lock_upgrade(rtld_bind_lock, &lockstate); 3357 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3358 lock_release(rtld_bind_lock, &lockstate); 3359 } 3360 lo_flags = RTLD_LO_DLOPEN; 3361 if (mode & RTLD_NODELETE) 3362 lo_flags |= RTLD_LO_NODELETE; 3363 if (mode & RTLD_NOLOAD) 3364 lo_flags |= RTLD_LO_NOLOAD; 3365 if (ld_tracing != NULL) 3366 lo_flags |= RTLD_LO_TRACE; 3367 3368 return (dlopen_object(name, fd, obj_main, lo_flags, 3369 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3370 } 3371 3372 static void 3373 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3374 { 3375 3376 obj->dl_refcount--; 3377 unref_dag(obj); 3378 if (obj->refcount == 0) 3379 unload_object(obj, lockstate); 3380 } 3381 3382 static Obj_Entry * 3383 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3384 int mode, RtldLockState *lockstate) 3385 { 3386 Obj_Entry *old_obj_tail; 3387 Obj_Entry *obj; 3388 Objlist initlist; 3389 RtldLockState mlockstate; 3390 int result; 3391 3392 objlist_init(&initlist); 3393 3394 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3395 wlock_acquire(rtld_bind_lock, &mlockstate); 3396 lockstate = &mlockstate; 3397 } 3398 GDB_STATE(RT_ADD,NULL); 3399 3400 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3401 obj = NULL; 3402 if (name == NULL && fd == -1) { 3403 obj = obj_main; 3404 obj->refcount++; 3405 } else { 3406 obj = load_object(name, fd, refobj, lo_flags); 3407 } 3408 3409 if (obj) { 3410 obj->dl_refcount++; 3411 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3412 objlist_push_tail(&list_global, obj); 3413 if (globallist_next(old_obj_tail) != NULL) { 3414 /* We loaded something new. */ 3415 assert(globallist_next(old_obj_tail) == obj); 3416 result = 0; 3417 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3418 !allocate_tls_offset(obj)) { 3419 _rtld_error("%s: No space available " 3420 "for static Thread Local Storage", obj->path); 3421 result = -1; 3422 } 3423 if (result != -1) 3424 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3425 RTLD_LO_EARLY)); 3426 init_dag(obj); 3427 ref_dag(obj); 3428 if (result != -1) 3429 result = rtld_verify_versions(&obj->dagmembers); 3430 if (result != -1 && ld_tracing) 3431 goto trace; 3432 if (result == -1 || relocate_object_dag(obj, 3433 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3434 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3435 lockstate) == -1) { 3436 dlopen_cleanup(obj, lockstate); 3437 obj = NULL; 3438 } else if (lo_flags & RTLD_LO_EARLY) { 3439 /* 3440 * Do not call the init functions for early loaded 3441 * filtees. The image is still not initialized enough 3442 * for them to work. 3443 * 3444 * Our object is found by the global object list and 3445 * will be ordered among all init calls done right 3446 * before transferring control to main. 3447 */ 3448 } else { 3449 /* Make list of init functions to call. */ 3450 initlist_add_objects(obj, obj, &initlist); 3451 } 3452 /* 3453 * Process all no_delete or global objects here, given 3454 * them own DAGs to prevent their dependencies from being 3455 * unloaded. This has to be done after we have loaded all 3456 * of the dependencies, so that we do not miss any. 3457 */ 3458 if (obj != NULL) 3459 process_z(obj); 3460 } else { 3461 /* 3462 * Bump the reference counts for objects on this DAG. If 3463 * this is the first dlopen() call for the object that was 3464 * already loaded as a dependency, initialize the dag 3465 * starting at it. 3466 */ 3467 init_dag(obj); 3468 ref_dag(obj); 3469 3470 if ((lo_flags & RTLD_LO_TRACE) != 0) 3471 goto trace; 3472 } 3473 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3474 obj->z_nodelete) && !obj->ref_nodel) { 3475 dbg("obj %s nodelete", obj->path); 3476 ref_dag(obj); 3477 obj->z_nodelete = obj->ref_nodel = true; 3478 } 3479 } 3480 3481 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3482 name); 3483 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3484 3485 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3486 map_stacks_exec(lockstate); 3487 if (obj != NULL) 3488 distribute_static_tls(&initlist, lockstate); 3489 } 3490 3491 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3492 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3493 lockstate) == -1) { 3494 objlist_clear(&initlist); 3495 dlopen_cleanup(obj, lockstate); 3496 if (lockstate == &mlockstate) 3497 lock_release(rtld_bind_lock, lockstate); 3498 return (NULL); 3499 } 3500 3501 if (!(lo_flags & RTLD_LO_EARLY)) { 3502 /* Call the init functions. */ 3503 objlist_call_init(&initlist, lockstate); 3504 } 3505 objlist_clear(&initlist); 3506 if (lockstate == &mlockstate) 3507 lock_release(rtld_bind_lock, lockstate); 3508 return obj; 3509 trace: 3510 trace_loaded_objects(obj); 3511 if (lockstate == &mlockstate) 3512 lock_release(rtld_bind_lock, lockstate); 3513 exit(0); 3514 } 3515 3516 static void * 3517 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3518 int flags) 3519 { 3520 DoneList donelist; 3521 const Obj_Entry *obj, *defobj; 3522 const Elf_Sym *def; 3523 SymLook req; 3524 RtldLockState lockstate; 3525 tls_index ti; 3526 void *sym; 3527 int res; 3528 3529 def = NULL; 3530 defobj = NULL; 3531 symlook_init(&req, name); 3532 req.ventry = ve; 3533 req.flags = flags | SYMLOOK_IN_PLT; 3534 req.lockstate = &lockstate; 3535 3536 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3537 rlock_acquire(rtld_bind_lock, &lockstate); 3538 if (sigsetjmp(lockstate.env, 0) != 0) 3539 lock_upgrade(rtld_bind_lock, &lockstate); 3540 if (handle == NULL || handle == RTLD_NEXT || 3541 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3542 3543 if ((obj = obj_from_addr(retaddr)) == NULL) { 3544 _rtld_error("Cannot determine caller's shared object"); 3545 lock_release(rtld_bind_lock, &lockstate); 3546 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3547 return NULL; 3548 } 3549 if (handle == NULL) { /* Just the caller's shared object. */ 3550 res = symlook_obj(&req, obj); 3551 if (res == 0) { 3552 def = req.sym_out; 3553 defobj = req.defobj_out; 3554 } 3555 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3556 handle == RTLD_SELF) { /* ... caller included */ 3557 if (handle == RTLD_NEXT) 3558 obj = globallist_next(obj); 3559 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3560 if (obj->marker) 3561 continue; 3562 res = symlook_obj(&req, obj); 3563 if (res == 0) { 3564 if (def == NULL || 3565 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3566 def = req.sym_out; 3567 defobj = req.defobj_out; 3568 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3569 break; 3570 } 3571 } 3572 } 3573 /* 3574 * Search the dynamic linker itself, and possibly resolve the 3575 * symbol from there. This is how the application links to 3576 * dynamic linker services such as dlopen. 3577 */ 3578 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3579 res = symlook_obj(&req, &obj_rtld); 3580 if (res == 0) { 3581 def = req.sym_out; 3582 defobj = req.defobj_out; 3583 } 3584 } 3585 } else { 3586 assert(handle == RTLD_DEFAULT); 3587 res = symlook_default(&req, obj); 3588 if (res == 0) { 3589 defobj = req.defobj_out; 3590 def = req.sym_out; 3591 } 3592 } 3593 } else { 3594 if ((obj = dlcheck(handle)) == NULL) { 3595 lock_release(rtld_bind_lock, &lockstate); 3596 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3597 return NULL; 3598 } 3599 3600 donelist_init(&donelist); 3601 if (obj->mainprog) { 3602 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3603 res = symlook_global(&req, &donelist); 3604 if (res == 0) { 3605 def = req.sym_out; 3606 defobj = req.defobj_out; 3607 } 3608 /* 3609 * Search the dynamic linker itself, and possibly resolve the 3610 * symbol from there. This is how the application links to 3611 * dynamic linker services such as dlopen. 3612 */ 3613 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3614 res = symlook_obj(&req, &obj_rtld); 3615 if (res == 0) { 3616 def = req.sym_out; 3617 defobj = req.defobj_out; 3618 } 3619 } 3620 } 3621 else { 3622 /* Search the whole DAG rooted at the given object. */ 3623 res = symlook_list(&req, &obj->dagmembers, &donelist); 3624 if (res == 0) { 3625 def = req.sym_out; 3626 defobj = req.defobj_out; 3627 } 3628 } 3629 } 3630 3631 if (def != NULL) { 3632 lock_release(rtld_bind_lock, &lockstate); 3633 3634 /* 3635 * The value required by the caller is derived from the value 3636 * of the symbol. this is simply the relocated value of the 3637 * symbol. 3638 */ 3639 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3640 sym = make_function_pointer(def, defobj); 3641 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3642 sym = rtld_resolve_ifunc(defobj, def); 3643 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3644 ti.ti_module = defobj->tlsindex; 3645 ti.ti_offset = def->st_value; 3646 sym = __tls_get_addr(&ti); 3647 } else 3648 sym = defobj->relocbase + def->st_value; 3649 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3650 return (sym); 3651 } 3652 3653 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3654 ve != NULL ? ve->name : ""); 3655 lock_release(rtld_bind_lock, &lockstate); 3656 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3657 return NULL; 3658 } 3659 3660 void * 3661 dlsym(void *handle, const char *name) 3662 { 3663 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3664 SYMLOOK_DLSYM); 3665 } 3666 3667 dlfunc_t 3668 dlfunc(void *handle, const char *name) 3669 { 3670 union { 3671 void *d; 3672 dlfunc_t f; 3673 } rv; 3674 3675 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3676 SYMLOOK_DLSYM); 3677 return (rv.f); 3678 } 3679 3680 void * 3681 dlvsym(void *handle, const char *name, const char *version) 3682 { 3683 Ver_Entry ventry; 3684 3685 ventry.name = version; 3686 ventry.file = NULL; 3687 ventry.hash = elf_hash(version); 3688 ventry.flags= 0; 3689 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3690 SYMLOOK_DLSYM); 3691 } 3692 3693 int 3694 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3695 { 3696 const Obj_Entry *obj; 3697 RtldLockState lockstate; 3698 3699 rlock_acquire(rtld_bind_lock, &lockstate); 3700 obj = obj_from_addr(addr); 3701 if (obj == NULL) { 3702 _rtld_error("No shared object contains address"); 3703 lock_release(rtld_bind_lock, &lockstate); 3704 return (0); 3705 } 3706 rtld_fill_dl_phdr_info(obj, phdr_info); 3707 lock_release(rtld_bind_lock, &lockstate); 3708 return (1); 3709 } 3710 3711 int 3712 dladdr(const void *addr, Dl_info *info) 3713 { 3714 const Obj_Entry *obj; 3715 const Elf_Sym *def; 3716 void *symbol_addr; 3717 unsigned long symoffset; 3718 RtldLockState lockstate; 3719 3720 rlock_acquire(rtld_bind_lock, &lockstate); 3721 obj = obj_from_addr(addr); 3722 if (obj == NULL) { 3723 _rtld_error("No shared object contains address"); 3724 lock_release(rtld_bind_lock, &lockstate); 3725 return 0; 3726 } 3727 info->dli_fname = obj->path; 3728 info->dli_fbase = obj->mapbase; 3729 info->dli_saddr = (void *)0; 3730 info->dli_sname = NULL; 3731 3732 /* 3733 * Walk the symbol list looking for the symbol whose address is 3734 * closest to the address sent in. 3735 */ 3736 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3737 def = obj->symtab + symoffset; 3738 3739 /* 3740 * For skip the symbol if st_shndx is either SHN_UNDEF or 3741 * SHN_COMMON. 3742 */ 3743 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3744 continue; 3745 3746 /* 3747 * If the symbol is greater than the specified address, or if it 3748 * is further away from addr than the current nearest symbol, 3749 * then reject it. 3750 */ 3751 symbol_addr = obj->relocbase + def->st_value; 3752 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3753 continue; 3754 3755 /* Update our idea of the nearest symbol. */ 3756 info->dli_sname = obj->strtab + def->st_name; 3757 info->dli_saddr = symbol_addr; 3758 3759 /* Exact match? */ 3760 if (info->dli_saddr == addr) 3761 break; 3762 } 3763 lock_release(rtld_bind_lock, &lockstate); 3764 return 1; 3765 } 3766 3767 int 3768 dlinfo(void *handle, int request, void *p) 3769 { 3770 const Obj_Entry *obj; 3771 RtldLockState lockstate; 3772 int error; 3773 3774 rlock_acquire(rtld_bind_lock, &lockstate); 3775 3776 if (handle == NULL || handle == RTLD_SELF) { 3777 void *retaddr; 3778 3779 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3780 if ((obj = obj_from_addr(retaddr)) == NULL) 3781 _rtld_error("Cannot determine caller's shared object"); 3782 } else 3783 obj = dlcheck(handle); 3784 3785 if (obj == NULL) { 3786 lock_release(rtld_bind_lock, &lockstate); 3787 return (-1); 3788 } 3789 3790 error = 0; 3791 switch (request) { 3792 case RTLD_DI_LINKMAP: 3793 *((struct link_map const **)p) = &obj->linkmap; 3794 break; 3795 case RTLD_DI_ORIGIN: 3796 error = rtld_dirname(obj->path, p); 3797 break; 3798 3799 case RTLD_DI_SERINFOSIZE: 3800 case RTLD_DI_SERINFO: 3801 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3802 break; 3803 3804 default: 3805 _rtld_error("Invalid request %d passed to dlinfo()", request); 3806 error = -1; 3807 } 3808 3809 lock_release(rtld_bind_lock, &lockstate); 3810 3811 return (error); 3812 } 3813 3814 static void 3815 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3816 { 3817 3818 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3819 phdr_info->dlpi_name = obj->path; 3820 phdr_info->dlpi_phdr = obj->phdr; 3821 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3822 phdr_info->dlpi_tls_modid = obj->tlsindex; 3823 phdr_info->dlpi_tls_data = obj->tlsinit; 3824 phdr_info->dlpi_adds = obj_loads; 3825 phdr_info->dlpi_subs = obj_loads - obj_count; 3826 } 3827 3828 int 3829 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3830 { 3831 struct dl_phdr_info phdr_info; 3832 Obj_Entry *obj, marker; 3833 RtldLockState bind_lockstate, phdr_lockstate; 3834 int error; 3835 3836 init_marker(&marker); 3837 error = 0; 3838 3839 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3840 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3841 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3842 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3843 rtld_fill_dl_phdr_info(obj, &phdr_info); 3844 hold_object(obj); 3845 lock_release(rtld_bind_lock, &bind_lockstate); 3846 3847 error = callback(&phdr_info, sizeof phdr_info, param); 3848 3849 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3850 unhold_object(obj); 3851 obj = globallist_next(&marker); 3852 TAILQ_REMOVE(&obj_list, &marker, next); 3853 if (error != 0) { 3854 lock_release(rtld_bind_lock, &bind_lockstate); 3855 lock_release(rtld_phdr_lock, &phdr_lockstate); 3856 return (error); 3857 } 3858 } 3859 3860 if (error == 0) { 3861 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3862 lock_release(rtld_bind_lock, &bind_lockstate); 3863 error = callback(&phdr_info, sizeof(phdr_info), param); 3864 } 3865 lock_release(rtld_phdr_lock, &phdr_lockstate); 3866 return (error); 3867 } 3868 3869 static void * 3870 fill_search_info(const char *dir, size_t dirlen, void *param) 3871 { 3872 struct fill_search_info_args *arg; 3873 3874 arg = param; 3875 3876 if (arg->request == RTLD_DI_SERINFOSIZE) { 3877 arg->serinfo->dls_cnt ++; 3878 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3879 } else { 3880 struct dl_serpath *s_entry; 3881 3882 s_entry = arg->serpath; 3883 s_entry->dls_name = arg->strspace; 3884 s_entry->dls_flags = arg->flags; 3885 3886 strncpy(arg->strspace, dir, dirlen); 3887 arg->strspace[dirlen] = '\0'; 3888 3889 arg->strspace += dirlen + 1; 3890 arg->serpath++; 3891 } 3892 3893 return (NULL); 3894 } 3895 3896 static int 3897 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3898 { 3899 struct dl_serinfo _info; 3900 struct fill_search_info_args args; 3901 3902 args.request = RTLD_DI_SERINFOSIZE; 3903 args.serinfo = &_info; 3904 3905 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3906 _info.dls_cnt = 0; 3907 3908 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3909 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3910 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3911 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3912 if (!obj->z_nodeflib) 3913 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3914 3915 3916 if (request == RTLD_DI_SERINFOSIZE) { 3917 info->dls_size = _info.dls_size; 3918 info->dls_cnt = _info.dls_cnt; 3919 return (0); 3920 } 3921 3922 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3923 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3924 return (-1); 3925 } 3926 3927 args.request = RTLD_DI_SERINFO; 3928 args.serinfo = info; 3929 args.serpath = &info->dls_serpath[0]; 3930 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3931 3932 args.flags = LA_SER_RUNPATH; 3933 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3934 return (-1); 3935 3936 args.flags = LA_SER_LIBPATH; 3937 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3938 return (-1); 3939 3940 args.flags = LA_SER_RUNPATH; 3941 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3942 return (-1); 3943 3944 args.flags = LA_SER_CONFIG; 3945 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3946 != NULL) 3947 return (-1); 3948 3949 args.flags = LA_SER_DEFAULT; 3950 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3951 fill_search_info, NULL, &args) != NULL) 3952 return (-1); 3953 return (0); 3954 } 3955 3956 static int 3957 rtld_dirname(const char *path, char *bname) 3958 { 3959 const char *endp; 3960 3961 /* Empty or NULL string gets treated as "." */ 3962 if (path == NULL || *path == '\0') { 3963 bname[0] = '.'; 3964 bname[1] = '\0'; 3965 return (0); 3966 } 3967 3968 /* Strip trailing slashes */ 3969 endp = path + strlen(path) - 1; 3970 while (endp > path && *endp == '/') 3971 endp--; 3972 3973 /* Find the start of the dir */ 3974 while (endp > path && *endp != '/') 3975 endp--; 3976 3977 /* Either the dir is "/" or there are no slashes */ 3978 if (endp == path) { 3979 bname[0] = *endp == '/' ? '/' : '.'; 3980 bname[1] = '\0'; 3981 return (0); 3982 } else { 3983 do { 3984 endp--; 3985 } while (endp > path && *endp == '/'); 3986 } 3987 3988 if (endp - path + 2 > PATH_MAX) 3989 { 3990 _rtld_error("Filename is too long: %s", path); 3991 return(-1); 3992 } 3993 3994 strncpy(bname, path, endp - path + 1); 3995 bname[endp - path + 1] = '\0'; 3996 return (0); 3997 } 3998 3999 static int 4000 rtld_dirname_abs(const char *path, char *base) 4001 { 4002 char *last; 4003 4004 if (realpath(path, base) == NULL) { 4005 _rtld_error("realpath \"%s\" failed (%s)", path, 4006 rtld_strerror(errno)); 4007 return (-1); 4008 } 4009 dbg("%s -> %s", path, base); 4010 last = strrchr(base, '/'); 4011 if (last == NULL) { 4012 _rtld_error("non-abs result from realpath \"%s\"", path); 4013 return (-1); 4014 } 4015 if (last != base) 4016 *last = '\0'; 4017 return (0); 4018 } 4019 4020 static void 4021 linkmap_add(Obj_Entry *obj) 4022 { 4023 struct link_map *l = &obj->linkmap; 4024 struct link_map *prev; 4025 4026 obj->linkmap.l_name = obj->path; 4027 obj->linkmap.l_addr = obj->mapbase; 4028 obj->linkmap.l_ld = obj->dynamic; 4029 #ifdef __mips__ 4030 /* GDB needs load offset on MIPS to use the symbols */ 4031 obj->linkmap.l_offs = obj->relocbase; 4032 #endif 4033 4034 if (r_debug.r_map == NULL) { 4035 r_debug.r_map = l; 4036 return; 4037 } 4038 4039 /* 4040 * Scan to the end of the list, but not past the entry for the 4041 * dynamic linker, which we want to keep at the very end. 4042 */ 4043 for (prev = r_debug.r_map; 4044 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4045 prev = prev->l_next) 4046 ; 4047 4048 /* Link in the new entry. */ 4049 l->l_prev = prev; 4050 l->l_next = prev->l_next; 4051 if (l->l_next != NULL) 4052 l->l_next->l_prev = l; 4053 prev->l_next = l; 4054 } 4055 4056 static void 4057 linkmap_delete(Obj_Entry *obj) 4058 { 4059 struct link_map *l = &obj->linkmap; 4060 4061 if (l->l_prev == NULL) { 4062 if ((r_debug.r_map = l->l_next) != NULL) 4063 l->l_next->l_prev = NULL; 4064 return; 4065 } 4066 4067 if ((l->l_prev->l_next = l->l_next) != NULL) 4068 l->l_next->l_prev = l->l_prev; 4069 } 4070 4071 /* 4072 * Function for the debugger to set a breakpoint on to gain control. 4073 * 4074 * The two parameters allow the debugger to easily find and determine 4075 * what the runtime loader is doing and to whom it is doing it. 4076 * 4077 * When the loadhook trap is hit (r_debug_state, set at program 4078 * initialization), the arguments can be found on the stack: 4079 * 4080 * +8 struct link_map *m 4081 * +4 struct r_debug *rd 4082 * +0 RetAddr 4083 */ 4084 void 4085 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4086 { 4087 /* 4088 * The following is a hack to force the compiler to emit calls to 4089 * this function, even when optimizing. If the function is empty, 4090 * the compiler is not obliged to emit any code for calls to it, 4091 * even when marked __noinline. However, gdb depends on those 4092 * calls being made. 4093 */ 4094 __compiler_membar(); 4095 } 4096 4097 /* 4098 * A function called after init routines have completed. This can be used to 4099 * break before a program's entry routine is called, and can be used when 4100 * main is not available in the symbol table. 4101 */ 4102 void 4103 _r_debug_postinit(struct link_map *m __unused) 4104 { 4105 4106 /* See r_debug_state(). */ 4107 __compiler_membar(); 4108 } 4109 4110 static void 4111 release_object(Obj_Entry *obj) 4112 { 4113 4114 if (obj->holdcount > 0) { 4115 obj->unholdfree = true; 4116 return; 4117 } 4118 munmap(obj->mapbase, obj->mapsize); 4119 linkmap_delete(obj); 4120 obj_free(obj); 4121 } 4122 4123 /* 4124 * Get address of the pointer variable in the main program. 4125 * Prefer non-weak symbol over the weak one. 4126 */ 4127 static const void ** 4128 get_program_var_addr(const char *name, RtldLockState *lockstate) 4129 { 4130 SymLook req; 4131 DoneList donelist; 4132 4133 symlook_init(&req, name); 4134 req.lockstate = lockstate; 4135 donelist_init(&donelist); 4136 if (symlook_global(&req, &donelist) != 0) 4137 return (NULL); 4138 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4139 return ((const void **)make_function_pointer(req.sym_out, 4140 req.defobj_out)); 4141 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4142 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4143 else 4144 return ((const void **)(req.defobj_out->relocbase + 4145 req.sym_out->st_value)); 4146 } 4147 4148 /* 4149 * Set a pointer variable in the main program to the given value. This 4150 * is used to set key variables such as "environ" before any of the 4151 * init functions are called. 4152 */ 4153 static void 4154 set_program_var(const char *name, const void *value) 4155 { 4156 const void **addr; 4157 4158 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4159 dbg("\"%s\": *%p <-- %p", name, addr, value); 4160 *addr = value; 4161 } 4162 } 4163 4164 /* 4165 * Search the global objects, including dependencies and main object, 4166 * for the given symbol. 4167 */ 4168 static int 4169 symlook_global(SymLook *req, DoneList *donelist) 4170 { 4171 SymLook req1; 4172 const Objlist_Entry *elm; 4173 int res; 4174 4175 symlook_init_from_req(&req1, req); 4176 4177 /* Search all objects loaded at program start up. */ 4178 if (req->defobj_out == NULL || 4179 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4180 res = symlook_list(&req1, &list_main, donelist); 4181 if (res == 0 && (req->defobj_out == NULL || 4182 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4183 req->sym_out = req1.sym_out; 4184 req->defobj_out = req1.defobj_out; 4185 assert(req->defobj_out != NULL); 4186 } 4187 } 4188 4189 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4190 STAILQ_FOREACH(elm, &list_global, link) { 4191 if (req->defobj_out != NULL && 4192 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4193 break; 4194 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4195 if (res == 0 && (req->defobj_out == NULL || 4196 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4197 req->sym_out = req1.sym_out; 4198 req->defobj_out = req1.defobj_out; 4199 assert(req->defobj_out != NULL); 4200 } 4201 } 4202 4203 return (req->sym_out != NULL ? 0 : ESRCH); 4204 } 4205 4206 /* 4207 * Given a symbol name in a referencing object, find the corresponding 4208 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4209 * no definition was found. Returns a pointer to the Obj_Entry of the 4210 * defining object via the reference parameter DEFOBJ_OUT. 4211 */ 4212 static int 4213 symlook_default(SymLook *req, const Obj_Entry *refobj) 4214 { 4215 DoneList donelist; 4216 const Objlist_Entry *elm; 4217 SymLook req1; 4218 int res; 4219 4220 donelist_init(&donelist); 4221 symlook_init_from_req(&req1, req); 4222 4223 /* 4224 * Look first in the referencing object if linked symbolically, 4225 * and similarly handle protected symbols. 4226 */ 4227 res = symlook_obj(&req1, refobj); 4228 if (res == 0 && (refobj->symbolic || 4229 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4230 req->sym_out = req1.sym_out; 4231 req->defobj_out = req1.defobj_out; 4232 assert(req->defobj_out != NULL); 4233 } 4234 if (refobj->symbolic || req->defobj_out != NULL) 4235 donelist_check(&donelist, refobj); 4236 4237 symlook_global(req, &donelist); 4238 4239 /* Search all dlopened DAGs containing the referencing object. */ 4240 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4241 if (req->sym_out != NULL && 4242 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4243 break; 4244 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4245 if (res == 0 && (req->sym_out == NULL || 4246 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4247 req->sym_out = req1.sym_out; 4248 req->defobj_out = req1.defobj_out; 4249 assert(req->defobj_out != NULL); 4250 } 4251 } 4252 4253 /* 4254 * Search the dynamic linker itself, and possibly resolve the 4255 * symbol from there. This is how the application links to 4256 * dynamic linker services such as dlopen. 4257 */ 4258 if (req->sym_out == NULL || 4259 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4260 res = symlook_obj(&req1, &obj_rtld); 4261 if (res == 0) { 4262 req->sym_out = req1.sym_out; 4263 req->defobj_out = req1.defobj_out; 4264 assert(req->defobj_out != NULL); 4265 } 4266 } 4267 4268 return (req->sym_out != NULL ? 0 : ESRCH); 4269 } 4270 4271 static int 4272 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4273 { 4274 const Elf_Sym *def; 4275 const Obj_Entry *defobj; 4276 const Objlist_Entry *elm; 4277 SymLook req1; 4278 int res; 4279 4280 def = NULL; 4281 defobj = NULL; 4282 STAILQ_FOREACH(elm, objlist, link) { 4283 if (donelist_check(dlp, elm->obj)) 4284 continue; 4285 symlook_init_from_req(&req1, req); 4286 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4287 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4288 def = req1.sym_out; 4289 defobj = req1.defobj_out; 4290 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4291 break; 4292 } 4293 } 4294 } 4295 if (def != NULL) { 4296 req->sym_out = def; 4297 req->defobj_out = defobj; 4298 return (0); 4299 } 4300 return (ESRCH); 4301 } 4302 4303 /* 4304 * Search the chain of DAGS cointed to by the given Needed_Entry 4305 * for a symbol of the given name. Each DAG is scanned completely 4306 * before advancing to the next one. Returns a pointer to the symbol, 4307 * or NULL if no definition was found. 4308 */ 4309 static int 4310 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4311 { 4312 const Elf_Sym *def; 4313 const Needed_Entry *n; 4314 const Obj_Entry *defobj; 4315 SymLook req1; 4316 int res; 4317 4318 def = NULL; 4319 defobj = NULL; 4320 symlook_init_from_req(&req1, req); 4321 for (n = needed; n != NULL; n = n->next) { 4322 if (n->obj == NULL || 4323 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4324 continue; 4325 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4326 def = req1.sym_out; 4327 defobj = req1.defobj_out; 4328 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4329 break; 4330 } 4331 } 4332 if (def != NULL) { 4333 req->sym_out = def; 4334 req->defobj_out = defobj; 4335 return (0); 4336 } 4337 return (ESRCH); 4338 } 4339 4340 /* 4341 * Search the symbol table of a single shared object for a symbol of 4342 * the given name and version, if requested. Returns a pointer to the 4343 * symbol, or NULL if no definition was found. If the object is 4344 * filter, return filtered symbol from filtee. 4345 * 4346 * The symbol's hash value is passed in for efficiency reasons; that 4347 * eliminates many recomputations of the hash value. 4348 */ 4349 int 4350 symlook_obj(SymLook *req, const Obj_Entry *obj) 4351 { 4352 DoneList donelist; 4353 SymLook req1; 4354 int flags, res, mres; 4355 4356 /* 4357 * If there is at least one valid hash at this point, we prefer to 4358 * use the faster GNU version if available. 4359 */ 4360 if (obj->valid_hash_gnu) 4361 mres = symlook_obj1_gnu(req, obj); 4362 else if (obj->valid_hash_sysv) 4363 mres = symlook_obj1_sysv(req, obj); 4364 else 4365 return (EINVAL); 4366 4367 if (mres == 0) { 4368 if (obj->needed_filtees != NULL) { 4369 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4370 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4371 donelist_init(&donelist); 4372 symlook_init_from_req(&req1, req); 4373 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4374 if (res == 0) { 4375 req->sym_out = req1.sym_out; 4376 req->defobj_out = req1.defobj_out; 4377 } 4378 return (res); 4379 } 4380 if (obj->needed_aux_filtees != NULL) { 4381 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4382 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4383 donelist_init(&donelist); 4384 symlook_init_from_req(&req1, req); 4385 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4386 if (res == 0) { 4387 req->sym_out = req1.sym_out; 4388 req->defobj_out = req1.defobj_out; 4389 return (res); 4390 } 4391 } 4392 } 4393 return (mres); 4394 } 4395 4396 /* Symbol match routine common to both hash functions */ 4397 static bool 4398 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4399 const unsigned long symnum) 4400 { 4401 Elf_Versym verndx; 4402 const Elf_Sym *symp; 4403 const char *strp; 4404 4405 symp = obj->symtab + symnum; 4406 strp = obj->strtab + symp->st_name; 4407 4408 switch (ELF_ST_TYPE(symp->st_info)) { 4409 case STT_FUNC: 4410 case STT_NOTYPE: 4411 case STT_OBJECT: 4412 case STT_COMMON: 4413 case STT_GNU_IFUNC: 4414 if (symp->st_value == 0) 4415 return (false); 4416 /* fallthrough */ 4417 case STT_TLS: 4418 if (symp->st_shndx != SHN_UNDEF) 4419 break; 4420 #ifndef __mips__ 4421 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4422 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4423 break; 4424 #endif 4425 /* fallthrough */ 4426 default: 4427 return (false); 4428 } 4429 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4430 return (false); 4431 4432 if (req->ventry == NULL) { 4433 if (obj->versyms != NULL) { 4434 verndx = VER_NDX(obj->versyms[symnum]); 4435 if (verndx > obj->vernum) { 4436 _rtld_error( 4437 "%s: symbol %s references wrong version %d", 4438 obj->path, obj->strtab + symnum, verndx); 4439 return (false); 4440 } 4441 /* 4442 * If we are not called from dlsym (i.e. this 4443 * is a normal relocation from unversioned 4444 * binary), accept the symbol immediately if 4445 * it happens to have first version after this 4446 * shared object became versioned. Otherwise, 4447 * if symbol is versioned and not hidden, 4448 * remember it. If it is the only symbol with 4449 * this name exported by the shared object, it 4450 * will be returned as a match by the calling 4451 * function. If symbol is global (verndx < 2) 4452 * accept it unconditionally. 4453 */ 4454 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4455 verndx == VER_NDX_GIVEN) { 4456 result->sym_out = symp; 4457 return (true); 4458 } 4459 else if (verndx >= VER_NDX_GIVEN) { 4460 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4461 == 0) { 4462 if (result->vsymp == NULL) 4463 result->vsymp = symp; 4464 result->vcount++; 4465 } 4466 return (false); 4467 } 4468 } 4469 result->sym_out = symp; 4470 return (true); 4471 } 4472 if (obj->versyms == NULL) { 4473 if (object_match_name(obj, req->ventry->name)) { 4474 _rtld_error("%s: object %s should provide version %s " 4475 "for symbol %s", obj_rtld.path, obj->path, 4476 req->ventry->name, obj->strtab + symnum); 4477 return (false); 4478 } 4479 } else { 4480 verndx = VER_NDX(obj->versyms[symnum]); 4481 if (verndx > obj->vernum) { 4482 _rtld_error("%s: symbol %s references wrong version %d", 4483 obj->path, obj->strtab + symnum, verndx); 4484 return (false); 4485 } 4486 if (obj->vertab[verndx].hash != req->ventry->hash || 4487 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4488 /* 4489 * Version does not match. Look if this is a 4490 * global symbol and if it is not hidden. If 4491 * global symbol (verndx < 2) is available, 4492 * use it. Do not return symbol if we are 4493 * called by dlvsym, because dlvsym looks for 4494 * a specific version and default one is not 4495 * what dlvsym wants. 4496 */ 4497 if ((req->flags & SYMLOOK_DLSYM) || 4498 (verndx >= VER_NDX_GIVEN) || 4499 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4500 return (false); 4501 } 4502 } 4503 result->sym_out = symp; 4504 return (true); 4505 } 4506 4507 /* 4508 * Search for symbol using SysV hash function. 4509 * obj->buckets is known not to be NULL at this point; the test for this was 4510 * performed with the obj->valid_hash_sysv assignment. 4511 */ 4512 static int 4513 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4514 { 4515 unsigned long symnum; 4516 Sym_Match_Result matchres; 4517 4518 matchres.sym_out = NULL; 4519 matchres.vsymp = NULL; 4520 matchres.vcount = 0; 4521 4522 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4523 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4524 if (symnum >= obj->nchains) 4525 return (ESRCH); /* Bad object */ 4526 4527 if (matched_symbol(req, obj, &matchres, symnum)) { 4528 req->sym_out = matchres.sym_out; 4529 req->defobj_out = obj; 4530 return (0); 4531 } 4532 } 4533 if (matchres.vcount == 1) { 4534 req->sym_out = matchres.vsymp; 4535 req->defobj_out = obj; 4536 return (0); 4537 } 4538 return (ESRCH); 4539 } 4540 4541 /* Search for symbol using GNU hash function */ 4542 static int 4543 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4544 { 4545 Elf_Addr bloom_word; 4546 const Elf32_Word *hashval; 4547 Elf32_Word bucket; 4548 Sym_Match_Result matchres; 4549 unsigned int h1, h2; 4550 unsigned long symnum; 4551 4552 matchres.sym_out = NULL; 4553 matchres.vsymp = NULL; 4554 matchres.vcount = 0; 4555 4556 /* Pick right bitmask word from Bloom filter array */ 4557 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4558 obj->maskwords_bm_gnu]; 4559 4560 /* Calculate modulus word size of gnu hash and its derivative */ 4561 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4562 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4563 4564 /* Filter out the "definitely not in set" queries */ 4565 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4566 return (ESRCH); 4567 4568 /* Locate hash chain and corresponding value element*/ 4569 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4570 if (bucket == 0) 4571 return (ESRCH); 4572 hashval = &obj->chain_zero_gnu[bucket]; 4573 do { 4574 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4575 symnum = hashval - obj->chain_zero_gnu; 4576 if (matched_symbol(req, obj, &matchres, symnum)) { 4577 req->sym_out = matchres.sym_out; 4578 req->defobj_out = obj; 4579 return (0); 4580 } 4581 } 4582 } while ((*hashval++ & 1) == 0); 4583 if (matchres.vcount == 1) { 4584 req->sym_out = matchres.vsymp; 4585 req->defobj_out = obj; 4586 return (0); 4587 } 4588 return (ESRCH); 4589 } 4590 4591 static void 4592 trace_loaded_objects(Obj_Entry *obj) 4593 { 4594 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4595 int c; 4596 4597 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4598 main_local = ""; 4599 4600 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4601 fmt1 = "\t%o => %p (%x)\n"; 4602 4603 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4604 fmt2 = "\t%o (%x)\n"; 4605 4606 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4607 4608 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4609 Needed_Entry *needed; 4610 const char *name, *path; 4611 bool is_lib; 4612 4613 if (obj->marker) 4614 continue; 4615 if (list_containers && obj->needed != NULL) 4616 rtld_printf("%s:\n", obj->path); 4617 for (needed = obj->needed; needed; needed = needed->next) { 4618 if (needed->obj != NULL) { 4619 if (needed->obj->traced && !list_containers) 4620 continue; 4621 needed->obj->traced = true; 4622 path = needed->obj->path; 4623 } else 4624 path = "not found"; 4625 4626 name = obj->strtab + needed->name; 4627 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4628 4629 fmt = is_lib ? fmt1 : fmt2; 4630 while ((c = *fmt++) != '\0') { 4631 switch (c) { 4632 default: 4633 rtld_putchar(c); 4634 continue; 4635 case '\\': 4636 switch (c = *fmt) { 4637 case '\0': 4638 continue; 4639 case 'n': 4640 rtld_putchar('\n'); 4641 break; 4642 case 't': 4643 rtld_putchar('\t'); 4644 break; 4645 } 4646 break; 4647 case '%': 4648 switch (c = *fmt) { 4649 case '\0': 4650 continue; 4651 case '%': 4652 default: 4653 rtld_putchar(c); 4654 break; 4655 case 'A': 4656 rtld_putstr(main_local); 4657 break; 4658 case 'a': 4659 rtld_putstr(obj_main->path); 4660 break; 4661 case 'o': 4662 rtld_putstr(name); 4663 break; 4664 #if 0 4665 case 'm': 4666 rtld_printf("%d", sodp->sod_major); 4667 break; 4668 case 'n': 4669 rtld_printf("%d", sodp->sod_minor); 4670 break; 4671 #endif 4672 case 'p': 4673 rtld_putstr(path); 4674 break; 4675 case 'x': 4676 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4677 0); 4678 break; 4679 } 4680 break; 4681 } 4682 ++fmt; 4683 } 4684 } 4685 } 4686 } 4687 4688 /* 4689 * Unload a dlopened object and its dependencies from memory and from 4690 * our data structures. It is assumed that the DAG rooted in the 4691 * object has already been unreferenced, and that the object has a 4692 * reference count of 0. 4693 */ 4694 static void 4695 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4696 { 4697 Obj_Entry marker, *obj, *next; 4698 4699 assert(root->refcount == 0); 4700 4701 /* 4702 * Pass over the DAG removing unreferenced objects from 4703 * appropriate lists. 4704 */ 4705 unlink_object(root); 4706 4707 /* Unmap all objects that are no longer referenced. */ 4708 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4709 next = TAILQ_NEXT(obj, next); 4710 if (obj->marker || obj->refcount != 0) 4711 continue; 4712 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4713 obj->mapsize, 0, obj->path); 4714 dbg("unloading \"%s\"", obj->path); 4715 /* 4716 * Unlink the object now to prevent new references from 4717 * being acquired while the bind lock is dropped in 4718 * recursive dlclose() invocations. 4719 */ 4720 TAILQ_REMOVE(&obj_list, obj, next); 4721 obj_count--; 4722 4723 if (obj->filtees_loaded) { 4724 if (next != NULL) { 4725 init_marker(&marker); 4726 TAILQ_INSERT_BEFORE(next, &marker, next); 4727 unload_filtees(obj, lockstate); 4728 next = TAILQ_NEXT(&marker, next); 4729 TAILQ_REMOVE(&obj_list, &marker, next); 4730 } else 4731 unload_filtees(obj, lockstate); 4732 } 4733 release_object(obj); 4734 } 4735 } 4736 4737 static void 4738 unlink_object(Obj_Entry *root) 4739 { 4740 Objlist_Entry *elm; 4741 4742 if (root->refcount == 0) { 4743 /* Remove the object from the RTLD_GLOBAL list. */ 4744 objlist_remove(&list_global, root); 4745 4746 /* Remove the object from all objects' DAG lists. */ 4747 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4748 objlist_remove(&elm->obj->dldags, root); 4749 if (elm->obj != root) 4750 unlink_object(elm->obj); 4751 } 4752 } 4753 } 4754 4755 static void 4756 ref_dag(Obj_Entry *root) 4757 { 4758 Objlist_Entry *elm; 4759 4760 assert(root->dag_inited); 4761 STAILQ_FOREACH(elm, &root->dagmembers, link) 4762 elm->obj->refcount++; 4763 } 4764 4765 static void 4766 unref_dag(Obj_Entry *root) 4767 { 4768 Objlist_Entry *elm; 4769 4770 assert(root->dag_inited); 4771 STAILQ_FOREACH(elm, &root->dagmembers, link) 4772 elm->obj->refcount--; 4773 } 4774 4775 /* 4776 * Common code for MD __tls_get_addr(). 4777 */ 4778 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4779 static void * 4780 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4781 { 4782 Elf_Addr *newdtv, *dtv; 4783 RtldLockState lockstate; 4784 int to_copy; 4785 4786 dtv = *dtvp; 4787 /* Check dtv generation in case new modules have arrived */ 4788 if (dtv[0] != tls_dtv_generation) { 4789 wlock_acquire(rtld_bind_lock, &lockstate); 4790 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4791 to_copy = dtv[1]; 4792 if (to_copy > tls_max_index) 4793 to_copy = tls_max_index; 4794 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4795 newdtv[0] = tls_dtv_generation; 4796 newdtv[1] = tls_max_index; 4797 free(dtv); 4798 lock_release(rtld_bind_lock, &lockstate); 4799 dtv = *dtvp = newdtv; 4800 } 4801 4802 /* Dynamically allocate module TLS if necessary */ 4803 if (dtv[index + 1] == 0) { 4804 /* Signal safe, wlock will block out signals. */ 4805 wlock_acquire(rtld_bind_lock, &lockstate); 4806 if (!dtv[index + 1]) 4807 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4808 lock_release(rtld_bind_lock, &lockstate); 4809 } 4810 return ((void *)(dtv[index + 1] + offset)); 4811 } 4812 4813 void * 4814 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4815 { 4816 Elf_Addr *dtv; 4817 4818 dtv = *dtvp; 4819 /* Check dtv generation in case new modules have arrived */ 4820 if (__predict_true(dtv[0] == tls_dtv_generation && 4821 dtv[index + 1] != 0)) 4822 return ((void *)(dtv[index + 1] + offset)); 4823 return (tls_get_addr_slow(dtvp, index, offset)); 4824 } 4825 4826 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4827 defined(__powerpc__) || defined(__riscv) 4828 4829 /* 4830 * Return pointer to allocated TLS block 4831 */ 4832 static void * 4833 get_tls_block_ptr(void *tcb, size_t tcbsize) 4834 { 4835 size_t extra_size, post_size, pre_size, tls_block_size; 4836 size_t tls_init_align; 4837 4838 tls_init_align = MAX(obj_main->tlsalign, 1); 4839 4840 /* Compute fragments sizes. */ 4841 extra_size = tcbsize - TLS_TCB_SIZE; 4842 post_size = calculate_tls_post_size(tls_init_align); 4843 tls_block_size = tcbsize + post_size; 4844 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4845 4846 return ((char *)tcb - pre_size - extra_size); 4847 } 4848 4849 /* 4850 * Allocate Static TLS using the Variant I method. 4851 * 4852 * For details on the layout, see lib/libc/gen/tls.c. 4853 * 4854 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4855 * it is based on tls_last_offset, and TLS offsets here are really TCB 4856 * offsets, whereas libc's tls_static_space is just the executable's static 4857 * TLS segment. 4858 */ 4859 void * 4860 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4861 { 4862 Obj_Entry *obj; 4863 char *tls_block; 4864 Elf_Addr *dtv, **tcb; 4865 Elf_Addr addr; 4866 Elf_Addr i; 4867 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4868 size_t tls_init_align; 4869 4870 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4871 return (oldtcb); 4872 4873 assert(tcbsize >= TLS_TCB_SIZE); 4874 maxalign = MAX(tcbalign, tls_static_max_align); 4875 tls_init_align = MAX(obj_main->tlsalign, 1); 4876 4877 /* Compute fragmets sizes. */ 4878 extra_size = tcbsize - TLS_TCB_SIZE; 4879 post_size = calculate_tls_post_size(tls_init_align); 4880 tls_block_size = tcbsize + post_size; 4881 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4882 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4883 4884 /* Allocate whole TLS block */ 4885 tls_block = malloc_aligned(tls_block_size, maxalign); 4886 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4887 4888 if (oldtcb != NULL) { 4889 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4890 tls_static_space); 4891 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4892 4893 /* Adjust the DTV. */ 4894 dtv = tcb[0]; 4895 for (i = 0; i < dtv[1]; i++) { 4896 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4897 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4898 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4899 } 4900 } 4901 } else { 4902 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4903 tcb[0] = dtv; 4904 dtv[0] = tls_dtv_generation; 4905 dtv[1] = tls_max_index; 4906 4907 for (obj = globallist_curr(objs); obj != NULL; 4908 obj = globallist_next(obj)) { 4909 if (obj->tlsoffset > 0) { 4910 addr = (Elf_Addr)tcb + obj->tlsoffset; 4911 if (obj->tlsinitsize > 0) 4912 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4913 if (obj->tlssize > obj->tlsinitsize) 4914 memset((void*)(addr + obj->tlsinitsize), 0, 4915 obj->tlssize - obj->tlsinitsize); 4916 dtv[obj->tlsindex + 1] = addr; 4917 } 4918 } 4919 } 4920 4921 return (tcb); 4922 } 4923 4924 void 4925 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4926 { 4927 Elf_Addr *dtv; 4928 Elf_Addr tlsstart, tlsend; 4929 size_t post_size; 4930 size_t dtvsize, i, tls_init_align; 4931 4932 assert(tcbsize >= TLS_TCB_SIZE); 4933 tls_init_align = MAX(obj_main->tlsalign, 1); 4934 4935 /* Compute fragments sizes. */ 4936 post_size = calculate_tls_post_size(tls_init_align); 4937 4938 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4939 tlsend = (Elf_Addr)tcb + tls_static_space; 4940 4941 dtv = *(Elf_Addr **)tcb; 4942 dtvsize = dtv[1]; 4943 for (i = 0; i < dtvsize; i++) { 4944 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4945 free((void*)dtv[i+2]); 4946 } 4947 } 4948 free(dtv); 4949 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4950 } 4951 4952 #endif 4953 4954 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4955 4956 /* 4957 * Allocate Static TLS using the Variant II method. 4958 */ 4959 void * 4960 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4961 { 4962 Obj_Entry *obj; 4963 size_t size, ralign; 4964 char *tls; 4965 Elf_Addr *dtv, *olddtv; 4966 Elf_Addr segbase, oldsegbase, addr; 4967 size_t i; 4968 4969 ralign = tcbalign; 4970 if (tls_static_max_align > ralign) 4971 ralign = tls_static_max_align; 4972 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4973 4974 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4975 tls = malloc_aligned(size, ralign); 4976 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4977 4978 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4979 ((Elf_Addr*)segbase)[0] = segbase; 4980 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4981 4982 dtv[0] = tls_dtv_generation; 4983 dtv[1] = tls_max_index; 4984 4985 if (oldtls) { 4986 /* 4987 * Copy the static TLS block over whole. 4988 */ 4989 oldsegbase = (Elf_Addr) oldtls; 4990 memcpy((void *)(segbase - tls_static_space), 4991 (const void *)(oldsegbase - tls_static_space), 4992 tls_static_space); 4993 4994 /* 4995 * If any dynamic TLS blocks have been created tls_get_addr(), 4996 * move them over. 4997 */ 4998 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4999 for (i = 0; i < olddtv[1]; i++) { 5000 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5001 dtv[i+2] = olddtv[i+2]; 5002 olddtv[i+2] = 0; 5003 } 5004 } 5005 5006 /* 5007 * We assume that this block was the one we created with 5008 * allocate_initial_tls(). 5009 */ 5010 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5011 } else { 5012 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5013 if (obj->marker || obj->tlsoffset == 0) 5014 continue; 5015 addr = segbase - obj->tlsoffset; 5016 memset((void*)(addr + obj->tlsinitsize), 5017 0, obj->tlssize - obj->tlsinitsize); 5018 if (obj->tlsinit) { 5019 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5020 obj->static_tls_copied = true; 5021 } 5022 dtv[obj->tlsindex + 1] = addr; 5023 } 5024 } 5025 5026 return (void*) segbase; 5027 } 5028 5029 void 5030 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5031 { 5032 Elf_Addr* dtv; 5033 size_t size, ralign; 5034 int dtvsize, i; 5035 Elf_Addr tlsstart, tlsend; 5036 5037 /* 5038 * Figure out the size of the initial TLS block so that we can 5039 * find stuff which ___tls_get_addr() allocated dynamically. 5040 */ 5041 ralign = tcbalign; 5042 if (tls_static_max_align > ralign) 5043 ralign = tls_static_max_align; 5044 size = round(tls_static_space, ralign); 5045 5046 dtv = ((Elf_Addr**)tls)[1]; 5047 dtvsize = dtv[1]; 5048 tlsend = (Elf_Addr) tls; 5049 tlsstart = tlsend - size; 5050 for (i = 0; i < dtvsize; i++) { 5051 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5052 free_aligned((void *)dtv[i + 2]); 5053 } 5054 } 5055 5056 free_aligned((void *)tlsstart); 5057 free((void*) dtv); 5058 } 5059 5060 #endif 5061 5062 /* 5063 * Allocate TLS block for module with given index. 5064 */ 5065 void * 5066 allocate_module_tls(int index) 5067 { 5068 Obj_Entry* obj; 5069 char* p; 5070 5071 TAILQ_FOREACH(obj, &obj_list, next) { 5072 if (obj->marker) 5073 continue; 5074 if (obj->tlsindex == index) 5075 break; 5076 } 5077 if (!obj) { 5078 _rtld_error("Can't find module with TLS index %d", index); 5079 rtld_die(); 5080 } 5081 5082 p = malloc_aligned(obj->tlssize, obj->tlsalign); 5083 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5084 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5085 5086 return p; 5087 } 5088 5089 bool 5090 allocate_tls_offset(Obj_Entry *obj) 5091 { 5092 size_t off; 5093 5094 if (obj->tls_done) 5095 return true; 5096 5097 if (obj->tlssize == 0) { 5098 obj->tls_done = true; 5099 return true; 5100 } 5101 5102 if (tls_last_offset == 0) 5103 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5104 else 5105 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5106 obj->tlssize, obj->tlsalign); 5107 5108 /* 5109 * If we have already fixed the size of the static TLS block, we 5110 * must stay within that size. When allocating the static TLS, we 5111 * leave a small amount of space spare to be used for dynamically 5112 * loading modules which use static TLS. 5113 */ 5114 if (tls_static_space != 0) { 5115 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5116 return false; 5117 } else if (obj->tlsalign > tls_static_max_align) { 5118 tls_static_max_align = obj->tlsalign; 5119 } 5120 5121 tls_last_offset = obj->tlsoffset = off; 5122 tls_last_size = obj->tlssize; 5123 obj->tls_done = true; 5124 5125 return true; 5126 } 5127 5128 void 5129 free_tls_offset(Obj_Entry *obj) 5130 { 5131 5132 /* 5133 * If we were the last thing to allocate out of the static TLS 5134 * block, we give our space back to the 'allocator'. This is a 5135 * simplistic workaround to allow libGL.so.1 to be loaded and 5136 * unloaded multiple times. 5137 */ 5138 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5139 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5140 tls_last_offset -= obj->tlssize; 5141 tls_last_size = 0; 5142 } 5143 } 5144 5145 void * 5146 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5147 { 5148 void *ret; 5149 RtldLockState lockstate; 5150 5151 wlock_acquire(rtld_bind_lock, &lockstate); 5152 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5153 tcbsize, tcbalign); 5154 lock_release(rtld_bind_lock, &lockstate); 5155 return (ret); 5156 } 5157 5158 void 5159 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5160 { 5161 RtldLockState lockstate; 5162 5163 wlock_acquire(rtld_bind_lock, &lockstate); 5164 free_tls(tcb, tcbsize, tcbalign); 5165 lock_release(rtld_bind_lock, &lockstate); 5166 } 5167 5168 static void 5169 object_add_name(Obj_Entry *obj, const char *name) 5170 { 5171 Name_Entry *entry; 5172 size_t len; 5173 5174 len = strlen(name); 5175 entry = malloc(sizeof(Name_Entry) + len); 5176 5177 if (entry != NULL) { 5178 strcpy(entry->name, name); 5179 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5180 } 5181 } 5182 5183 static int 5184 object_match_name(const Obj_Entry *obj, const char *name) 5185 { 5186 Name_Entry *entry; 5187 5188 STAILQ_FOREACH(entry, &obj->names, link) { 5189 if (strcmp(name, entry->name) == 0) 5190 return (1); 5191 } 5192 return (0); 5193 } 5194 5195 static Obj_Entry * 5196 locate_dependency(const Obj_Entry *obj, const char *name) 5197 { 5198 const Objlist_Entry *entry; 5199 const Needed_Entry *needed; 5200 5201 STAILQ_FOREACH(entry, &list_main, link) { 5202 if (object_match_name(entry->obj, name)) 5203 return entry->obj; 5204 } 5205 5206 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5207 if (strcmp(obj->strtab + needed->name, name) == 0 || 5208 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5209 /* 5210 * If there is DT_NEEDED for the name we are looking for, 5211 * we are all set. Note that object might not be found if 5212 * dependency was not loaded yet, so the function can 5213 * return NULL here. This is expected and handled 5214 * properly by the caller. 5215 */ 5216 return (needed->obj); 5217 } 5218 } 5219 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5220 obj->path, name); 5221 rtld_die(); 5222 } 5223 5224 static int 5225 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5226 const Elf_Vernaux *vna) 5227 { 5228 const Elf_Verdef *vd; 5229 const char *vername; 5230 5231 vername = refobj->strtab + vna->vna_name; 5232 vd = depobj->verdef; 5233 if (vd == NULL) { 5234 _rtld_error("%s: version %s required by %s not defined", 5235 depobj->path, vername, refobj->path); 5236 return (-1); 5237 } 5238 for (;;) { 5239 if (vd->vd_version != VER_DEF_CURRENT) { 5240 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5241 depobj->path, vd->vd_version); 5242 return (-1); 5243 } 5244 if (vna->vna_hash == vd->vd_hash) { 5245 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5246 ((const char *)vd + vd->vd_aux); 5247 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5248 return (0); 5249 } 5250 if (vd->vd_next == 0) 5251 break; 5252 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5253 } 5254 if (vna->vna_flags & VER_FLG_WEAK) 5255 return (0); 5256 _rtld_error("%s: version %s required by %s not found", 5257 depobj->path, vername, refobj->path); 5258 return (-1); 5259 } 5260 5261 static int 5262 rtld_verify_object_versions(Obj_Entry *obj) 5263 { 5264 const Elf_Verneed *vn; 5265 const Elf_Verdef *vd; 5266 const Elf_Verdaux *vda; 5267 const Elf_Vernaux *vna; 5268 const Obj_Entry *depobj; 5269 int maxvernum, vernum; 5270 5271 if (obj->ver_checked) 5272 return (0); 5273 obj->ver_checked = true; 5274 5275 maxvernum = 0; 5276 /* 5277 * Walk over defined and required version records and figure out 5278 * max index used by any of them. Do very basic sanity checking 5279 * while there. 5280 */ 5281 vn = obj->verneed; 5282 while (vn != NULL) { 5283 if (vn->vn_version != VER_NEED_CURRENT) { 5284 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5285 obj->path, vn->vn_version); 5286 return (-1); 5287 } 5288 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5289 for (;;) { 5290 vernum = VER_NEED_IDX(vna->vna_other); 5291 if (vernum > maxvernum) 5292 maxvernum = vernum; 5293 if (vna->vna_next == 0) 5294 break; 5295 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5296 } 5297 if (vn->vn_next == 0) 5298 break; 5299 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5300 } 5301 5302 vd = obj->verdef; 5303 while (vd != NULL) { 5304 if (vd->vd_version != VER_DEF_CURRENT) { 5305 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5306 obj->path, vd->vd_version); 5307 return (-1); 5308 } 5309 vernum = VER_DEF_IDX(vd->vd_ndx); 5310 if (vernum > maxvernum) 5311 maxvernum = vernum; 5312 if (vd->vd_next == 0) 5313 break; 5314 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5315 } 5316 5317 if (maxvernum == 0) 5318 return (0); 5319 5320 /* 5321 * Store version information in array indexable by version index. 5322 * Verify that object version requirements are satisfied along the 5323 * way. 5324 */ 5325 obj->vernum = maxvernum + 1; 5326 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5327 5328 vd = obj->verdef; 5329 while (vd != NULL) { 5330 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5331 vernum = VER_DEF_IDX(vd->vd_ndx); 5332 assert(vernum <= maxvernum); 5333 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5334 obj->vertab[vernum].hash = vd->vd_hash; 5335 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5336 obj->vertab[vernum].file = NULL; 5337 obj->vertab[vernum].flags = 0; 5338 } 5339 if (vd->vd_next == 0) 5340 break; 5341 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5342 } 5343 5344 vn = obj->verneed; 5345 while (vn != NULL) { 5346 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5347 if (depobj == NULL) 5348 return (-1); 5349 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5350 for (;;) { 5351 if (check_object_provided_version(obj, depobj, vna)) 5352 return (-1); 5353 vernum = VER_NEED_IDX(vna->vna_other); 5354 assert(vernum <= maxvernum); 5355 obj->vertab[vernum].hash = vna->vna_hash; 5356 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5357 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5358 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5359 VER_INFO_HIDDEN : 0; 5360 if (vna->vna_next == 0) 5361 break; 5362 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5363 } 5364 if (vn->vn_next == 0) 5365 break; 5366 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5367 } 5368 return 0; 5369 } 5370 5371 static int 5372 rtld_verify_versions(const Objlist *objlist) 5373 { 5374 Objlist_Entry *entry; 5375 int rc; 5376 5377 rc = 0; 5378 STAILQ_FOREACH(entry, objlist, link) { 5379 /* 5380 * Skip dummy objects or objects that have their version requirements 5381 * already checked. 5382 */ 5383 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5384 continue; 5385 if (rtld_verify_object_versions(entry->obj) == -1) { 5386 rc = -1; 5387 if (ld_tracing == NULL) 5388 break; 5389 } 5390 } 5391 if (rc == 0 || ld_tracing != NULL) 5392 rc = rtld_verify_object_versions(&obj_rtld); 5393 return rc; 5394 } 5395 5396 const Ver_Entry * 5397 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5398 { 5399 Elf_Versym vernum; 5400 5401 if (obj->vertab) { 5402 vernum = VER_NDX(obj->versyms[symnum]); 5403 if (vernum >= obj->vernum) { 5404 _rtld_error("%s: symbol %s has wrong verneed value %d", 5405 obj->path, obj->strtab + symnum, vernum); 5406 } else if (obj->vertab[vernum].hash != 0) { 5407 return &obj->vertab[vernum]; 5408 } 5409 } 5410 return NULL; 5411 } 5412 5413 int 5414 _rtld_get_stack_prot(void) 5415 { 5416 5417 return (stack_prot); 5418 } 5419 5420 int 5421 _rtld_is_dlopened(void *arg) 5422 { 5423 Obj_Entry *obj; 5424 RtldLockState lockstate; 5425 int res; 5426 5427 rlock_acquire(rtld_bind_lock, &lockstate); 5428 obj = dlcheck(arg); 5429 if (obj == NULL) 5430 obj = obj_from_addr(arg); 5431 if (obj == NULL) { 5432 _rtld_error("No shared object contains address"); 5433 lock_release(rtld_bind_lock, &lockstate); 5434 return (-1); 5435 } 5436 res = obj->dlopened ? 1 : 0; 5437 lock_release(rtld_bind_lock, &lockstate); 5438 return (res); 5439 } 5440 5441 static int 5442 obj_remap_relro(Obj_Entry *obj, int prot) 5443 { 5444 5445 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5446 prot) == -1) { 5447 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5448 obj->path, prot, rtld_strerror(errno)); 5449 return (-1); 5450 } 5451 return (0); 5452 } 5453 5454 static int 5455 obj_disable_relro(Obj_Entry *obj) 5456 { 5457 5458 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5459 } 5460 5461 static int 5462 obj_enforce_relro(Obj_Entry *obj) 5463 { 5464 5465 return (obj_remap_relro(obj, PROT_READ)); 5466 } 5467 5468 static void 5469 map_stacks_exec(RtldLockState *lockstate) 5470 { 5471 void (*thr_map_stacks_exec)(void); 5472 5473 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5474 return; 5475 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5476 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5477 if (thr_map_stacks_exec != NULL) { 5478 stack_prot |= PROT_EXEC; 5479 thr_map_stacks_exec(); 5480 } 5481 } 5482 5483 static void 5484 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5485 { 5486 Objlist_Entry *elm; 5487 Obj_Entry *obj; 5488 void (*distrib)(size_t, void *, size_t, size_t); 5489 5490 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5491 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5492 if (distrib == NULL) 5493 return; 5494 STAILQ_FOREACH(elm, list, link) { 5495 obj = elm->obj; 5496 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5497 continue; 5498 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5499 obj->tlssize); 5500 obj->static_tls_copied = true; 5501 } 5502 } 5503 5504 void 5505 symlook_init(SymLook *dst, const char *name) 5506 { 5507 5508 bzero(dst, sizeof(*dst)); 5509 dst->name = name; 5510 dst->hash = elf_hash(name); 5511 dst->hash_gnu = gnu_hash(name); 5512 } 5513 5514 static void 5515 symlook_init_from_req(SymLook *dst, const SymLook *src) 5516 { 5517 5518 dst->name = src->name; 5519 dst->hash = src->hash; 5520 dst->hash_gnu = src->hash_gnu; 5521 dst->ventry = src->ventry; 5522 dst->flags = src->flags; 5523 dst->defobj_out = NULL; 5524 dst->sym_out = NULL; 5525 dst->lockstate = src->lockstate; 5526 } 5527 5528 static int 5529 open_binary_fd(const char *argv0, bool search_in_path, 5530 const char **binpath_res) 5531 { 5532 char *binpath, *pathenv, *pe, *res1; 5533 const char *res; 5534 int fd; 5535 5536 binpath = NULL; 5537 res = NULL; 5538 if (search_in_path && strchr(argv0, '/') == NULL) { 5539 binpath = xmalloc(PATH_MAX); 5540 pathenv = getenv("PATH"); 5541 if (pathenv == NULL) { 5542 _rtld_error("-p and no PATH environment variable"); 5543 rtld_die(); 5544 } 5545 pathenv = strdup(pathenv); 5546 if (pathenv == NULL) { 5547 _rtld_error("Cannot allocate memory"); 5548 rtld_die(); 5549 } 5550 fd = -1; 5551 errno = ENOENT; 5552 while ((pe = strsep(&pathenv, ":")) != NULL) { 5553 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5554 continue; 5555 if (binpath[0] != '\0' && 5556 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5557 continue; 5558 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5559 continue; 5560 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5561 if (fd != -1 || errno != ENOENT) { 5562 res = binpath; 5563 break; 5564 } 5565 } 5566 free(pathenv); 5567 } else { 5568 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5569 res = argv0; 5570 } 5571 5572 if (fd == -1) { 5573 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5574 rtld_die(); 5575 } 5576 if (res != NULL && res[0] != '/') { 5577 res1 = xmalloc(PATH_MAX); 5578 if (realpath(res, res1) != NULL) { 5579 if (res != argv0) 5580 free(__DECONST(char *, res)); 5581 res = res1; 5582 } else { 5583 free(res1); 5584 } 5585 } 5586 *binpath_res = res; 5587 return (fd); 5588 } 5589 5590 /* 5591 * Parse a set of command-line arguments. 5592 */ 5593 static int 5594 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5595 { 5596 const char *arg; 5597 int fd, i, j, arglen; 5598 char opt; 5599 5600 dbg("Parsing command-line arguments"); 5601 *use_pathp = false; 5602 *fdp = -1; 5603 5604 for (i = 1; i < argc; i++ ) { 5605 arg = argv[i]; 5606 dbg("argv[%d]: '%s'", i, arg); 5607 5608 /* 5609 * rtld arguments end with an explicit "--" or with the first 5610 * non-prefixed argument. 5611 */ 5612 if (strcmp(arg, "--") == 0) { 5613 i++; 5614 break; 5615 } 5616 if (arg[0] != '-') 5617 break; 5618 5619 /* 5620 * All other arguments are single-character options that can 5621 * be combined, so we need to search through `arg` for them. 5622 */ 5623 arglen = strlen(arg); 5624 for (j = 1; j < arglen; j++) { 5625 opt = arg[j]; 5626 if (opt == 'h') { 5627 print_usage(argv[0]); 5628 _exit(0); 5629 } else if (opt == 'f') { 5630 /* 5631 * -f XX can be used to specify a descriptor for the 5632 * binary named at the command line (i.e., the later 5633 * argument will specify the process name but the 5634 * descriptor is what will actually be executed) 5635 */ 5636 if (j != arglen - 1) { 5637 /* -f must be the last option in, e.g., -abcf */ 5638 _rtld_error("Invalid options: %s", arg); 5639 rtld_die(); 5640 } 5641 i++; 5642 fd = parse_integer(argv[i]); 5643 if (fd == -1) { 5644 _rtld_error("Invalid file descriptor: '%s'", 5645 argv[i]); 5646 rtld_die(); 5647 } 5648 *fdp = fd; 5649 break; 5650 } else if (opt == 'p') { 5651 *use_pathp = true; 5652 } else { 5653 _rtld_error("Invalid argument: '%s'", arg); 5654 print_usage(argv[0]); 5655 rtld_die(); 5656 } 5657 } 5658 } 5659 5660 return (i); 5661 } 5662 5663 /* 5664 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5665 */ 5666 static int 5667 parse_integer(const char *str) 5668 { 5669 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5670 const char *orig; 5671 int n; 5672 char c; 5673 5674 orig = str; 5675 n = 0; 5676 for (c = *str; c != '\0'; c = *++str) { 5677 if (c < '0' || c > '9') 5678 return (-1); 5679 5680 n *= RADIX; 5681 n += c - '0'; 5682 } 5683 5684 /* Make sure we actually parsed something. */ 5685 if (str == orig) 5686 return (-1); 5687 return (n); 5688 } 5689 5690 static void 5691 print_usage(const char *argv0) 5692 { 5693 5694 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5695 "\n" 5696 "Options:\n" 5697 " -h Display this help message\n" 5698 " -p Search in PATH for named binary\n" 5699 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5700 " -- End of RTLD options\n" 5701 " <binary> Name of process to execute\n" 5702 " <args> Arguments to the executed process\n", argv0); 5703 } 5704 5705 /* 5706 * Overrides for libc_pic-provided functions. 5707 */ 5708 5709 int 5710 __getosreldate(void) 5711 { 5712 size_t len; 5713 int oid[2]; 5714 int error, osrel; 5715 5716 if (osreldate != 0) 5717 return (osreldate); 5718 5719 oid[0] = CTL_KERN; 5720 oid[1] = KERN_OSRELDATE; 5721 osrel = 0; 5722 len = sizeof(osrel); 5723 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5724 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5725 osreldate = osrel; 5726 return (osreldate); 5727 } 5728 const char * 5729 rtld_strerror(int errnum) 5730 { 5731 5732 if (errnum < 0 || errnum >= sys_nerr) 5733 return ("Unknown error"); 5734 return (sys_errlist[errnum]); 5735 } 5736 5737 /* malloc */ 5738 void * 5739 malloc(size_t nbytes) 5740 { 5741 5742 return (__crt_malloc(nbytes)); 5743 } 5744 5745 void * 5746 calloc(size_t num, size_t size) 5747 { 5748 5749 return (__crt_calloc(num, size)); 5750 } 5751 5752 void 5753 free(void *cp) 5754 { 5755 5756 __crt_free(cp); 5757 } 5758 5759 void * 5760 realloc(void *cp, size_t nbytes) 5761 { 5762 5763 return (__crt_realloc(cp, nbytes)); 5764 } 5765