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->irelative_nonplt && 3038 !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3039 return (0); 3040 if (obj_disable_relro(obj) == -1 || 3041 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3042 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3043 lockstate) == -1) || 3044 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3045 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3046 obj_enforce_relro(obj) == -1) 3047 return (-1); 3048 return (0); 3049 } 3050 3051 static int 3052 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3053 RtldLockState *lockstate) 3054 { 3055 Objlist_Entry *elm; 3056 Obj_Entry *obj; 3057 3058 STAILQ_FOREACH(elm, list, link) { 3059 obj = elm->obj; 3060 if (obj->marker) 3061 continue; 3062 if (resolve_object_ifunc(obj, bind_now, flags, 3063 lockstate) == -1) 3064 return (-1); 3065 } 3066 return (0); 3067 } 3068 3069 /* 3070 * Cleanup procedure. It will be called (by the atexit mechanism) just 3071 * before the process exits. 3072 */ 3073 static void 3074 rtld_exit(void) 3075 { 3076 RtldLockState lockstate; 3077 3078 wlock_acquire(rtld_bind_lock, &lockstate); 3079 dbg("rtld_exit()"); 3080 objlist_call_fini(&list_fini, NULL, &lockstate); 3081 /* No need to remove the items from the list, since we are exiting. */ 3082 if (!libmap_disable) 3083 lm_fini(); 3084 lock_release(rtld_bind_lock, &lockstate); 3085 } 3086 3087 static void 3088 rtld_nop_exit(void) 3089 { 3090 } 3091 3092 /* 3093 * Iterate over a search path, translate each element, and invoke the 3094 * callback on the result. 3095 */ 3096 static void * 3097 path_enumerate(const char *path, path_enum_proc callback, 3098 const char *refobj_path, void *arg) 3099 { 3100 const char *trans; 3101 if (path == NULL) 3102 return (NULL); 3103 3104 path += strspn(path, ":;"); 3105 while (*path != '\0') { 3106 size_t len; 3107 char *res; 3108 3109 len = strcspn(path, ":;"); 3110 trans = lm_findn(refobj_path, path, len); 3111 if (trans) 3112 res = callback(trans, strlen(trans), arg); 3113 else 3114 res = callback(path, len, arg); 3115 3116 if (res != NULL) 3117 return (res); 3118 3119 path += len; 3120 path += strspn(path, ":;"); 3121 } 3122 3123 return (NULL); 3124 } 3125 3126 struct try_library_args { 3127 const char *name; 3128 size_t namelen; 3129 char *buffer; 3130 size_t buflen; 3131 int fd; 3132 }; 3133 3134 static void * 3135 try_library_path(const char *dir, size_t dirlen, void *param) 3136 { 3137 struct try_library_args *arg; 3138 int fd; 3139 3140 arg = param; 3141 if (*dir == '/' || trust) { 3142 char *pathname; 3143 3144 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3145 return (NULL); 3146 3147 pathname = arg->buffer; 3148 strncpy(pathname, dir, dirlen); 3149 pathname[dirlen] = '/'; 3150 strcpy(pathname + dirlen + 1, arg->name); 3151 3152 dbg(" Trying \"%s\"", pathname); 3153 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3154 if (fd >= 0) { 3155 dbg(" Opened \"%s\", fd %d", pathname, fd); 3156 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3157 strcpy(pathname, arg->buffer); 3158 arg->fd = fd; 3159 return (pathname); 3160 } else { 3161 dbg(" Failed to open \"%s\": %s", 3162 pathname, rtld_strerror(errno)); 3163 } 3164 } 3165 return (NULL); 3166 } 3167 3168 static char * 3169 search_library_path(const char *name, const char *path, 3170 const char *refobj_path, int *fdp) 3171 { 3172 char *p; 3173 struct try_library_args arg; 3174 3175 if (path == NULL) 3176 return NULL; 3177 3178 arg.name = name; 3179 arg.namelen = strlen(name); 3180 arg.buffer = xmalloc(PATH_MAX); 3181 arg.buflen = PATH_MAX; 3182 arg.fd = -1; 3183 3184 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3185 *fdp = arg.fd; 3186 3187 free(arg.buffer); 3188 3189 return (p); 3190 } 3191 3192 3193 /* 3194 * Finds the library with the given name using the directory descriptors 3195 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3196 * 3197 * Returns a freshly-opened close-on-exec file descriptor for the library, 3198 * or -1 if the library cannot be found. 3199 */ 3200 static char * 3201 search_library_pathfds(const char *name, const char *path, int *fdp) 3202 { 3203 char *envcopy, *fdstr, *found, *last_token; 3204 size_t len; 3205 int dirfd, fd; 3206 3207 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3208 3209 /* Don't load from user-specified libdirs into setuid binaries. */ 3210 if (!trust) 3211 return (NULL); 3212 3213 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3214 if (path == NULL) 3215 return (NULL); 3216 3217 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3218 if (name[0] == '/') { 3219 dbg("Absolute path (%s) passed to %s", name, __func__); 3220 return (NULL); 3221 } 3222 3223 /* 3224 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3225 * copy of the path, as strtok_r rewrites separator tokens 3226 * with '\0'. 3227 */ 3228 found = NULL; 3229 envcopy = xstrdup(path); 3230 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3231 fdstr = strtok_r(NULL, ":", &last_token)) { 3232 dirfd = parse_integer(fdstr); 3233 if (dirfd < 0) { 3234 _rtld_error("failed to parse directory FD: '%s'", 3235 fdstr); 3236 break; 3237 } 3238 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3239 if (fd >= 0) { 3240 *fdp = fd; 3241 len = strlen(fdstr) + strlen(name) + 3; 3242 found = xmalloc(len); 3243 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3244 _rtld_error("error generating '%d/%s'", 3245 dirfd, name); 3246 rtld_die(); 3247 } 3248 dbg("open('%s') => %d", found, fd); 3249 break; 3250 } 3251 } 3252 free(envcopy); 3253 3254 return (found); 3255 } 3256 3257 3258 int 3259 dlclose(void *handle) 3260 { 3261 RtldLockState lockstate; 3262 int error; 3263 3264 wlock_acquire(rtld_bind_lock, &lockstate); 3265 error = dlclose_locked(handle, &lockstate); 3266 lock_release(rtld_bind_lock, &lockstate); 3267 return (error); 3268 } 3269 3270 static int 3271 dlclose_locked(void *handle, RtldLockState *lockstate) 3272 { 3273 Obj_Entry *root; 3274 3275 root = dlcheck(handle); 3276 if (root == NULL) 3277 return -1; 3278 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3279 root->path); 3280 3281 /* Unreference the object and its dependencies. */ 3282 root->dl_refcount--; 3283 3284 if (root->refcount == 1) { 3285 /* 3286 * The object will be no longer referenced, so we must unload it. 3287 * First, call the fini functions. 3288 */ 3289 objlist_call_fini(&list_fini, root, lockstate); 3290 3291 unref_dag(root); 3292 3293 /* Finish cleaning up the newly-unreferenced objects. */ 3294 GDB_STATE(RT_DELETE,&root->linkmap); 3295 unload_object(root, lockstate); 3296 GDB_STATE(RT_CONSISTENT,NULL); 3297 } else 3298 unref_dag(root); 3299 3300 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3301 return 0; 3302 } 3303 3304 char * 3305 dlerror(void) 3306 { 3307 char *msg = error_message; 3308 error_message = NULL; 3309 return msg; 3310 } 3311 3312 /* 3313 * This function is deprecated and has no effect. 3314 */ 3315 void 3316 dllockinit(void *context, 3317 void *(*_lock_create)(void *context) __unused, 3318 void (*_rlock_acquire)(void *lock) __unused, 3319 void (*_wlock_acquire)(void *lock) __unused, 3320 void (*_lock_release)(void *lock) __unused, 3321 void (*_lock_destroy)(void *lock) __unused, 3322 void (*context_destroy)(void *context)) 3323 { 3324 static void *cur_context; 3325 static void (*cur_context_destroy)(void *); 3326 3327 /* Just destroy the context from the previous call, if necessary. */ 3328 if (cur_context_destroy != NULL) 3329 cur_context_destroy(cur_context); 3330 cur_context = context; 3331 cur_context_destroy = context_destroy; 3332 } 3333 3334 void * 3335 dlopen(const char *name, int mode) 3336 { 3337 3338 return (rtld_dlopen(name, -1, mode)); 3339 } 3340 3341 void * 3342 fdlopen(int fd, int mode) 3343 { 3344 3345 return (rtld_dlopen(NULL, fd, mode)); 3346 } 3347 3348 static void * 3349 rtld_dlopen(const char *name, int fd, int mode) 3350 { 3351 RtldLockState lockstate; 3352 int lo_flags; 3353 3354 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3355 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3356 if (ld_tracing != NULL) { 3357 rlock_acquire(rtld_bind_lock, &lockstate); 3358 if (sigsetjmp(lockstate.env, 0) != 0) 3359 lock_upgrade(rtld_bind_lock, &lockstate); 3360 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3361 lock_release(rtld_bind_lock, &lockstate); 3362 } 3363 lo_flags = RTLD_LO_DLOPEN; 3364 if (mode & RTLD_NODELETE) 3365 lo_flags |= RTLD_LO_NODELETE; 3366 if (mode & RTLD_NOLOAD) 3367 lo_flags |= RTLD_LO_NOLOAD; 3368 if (ld_tracing != NULL) 3369 lo_flags |= RTLD_LO_TRACE; 3370 3371 return (dlopen_object(name, fd, obj_main, lo_flags, 3372 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3373 } 3374 3375 static void 3376 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3377 { 3378 3379 obj->dl_refcount--; 3380 unref_dag(obj); 3381 if (obj->refcount == 0) 3382 unload_object(obj, lockstate); 3383 } 3384 3385 static Obj_Entry * 3386 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3387 int mode, RtldLockState *lockstate) 3388 { 3389 Obj_Entry *old_obj_tail; 3390 Obj_Entry *obj; 3391 Objlist initlist; 3392 RtldLockState mlockstate; 3393 int result; 3394 3395 objlist_init(&initlist); 3396 3397 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3398 wlock_acquire(rtld_bind_lock, &mlockstate); 3399 lockstate = &mlockstate; 3400 } 3401 GDB_STATE(RT_ADD,NULL); 3402 3403 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3404 obj = NULL; 3405 if (name == NULL && fd == -1) { 3406 obj = obj_main; 3407 obj->refcount++; 3408 } else { 3409 obj = load_object(name, fd, refobj, lo_flags); 3410 } 3411 3412 if (obj) { 3413 obj->dl_refcount++; 3414 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3415 objlist_push_tail(&list_global, obj); 3416 if (globallist_next(old_obj_tail) != NULL) { 3417 /* We loaded something new. */ 3418 assert(globallist_next(old_obj_tail) == obj); 3419 result = 0; 3420 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3421 !allocate_tls_offset(obj)) { 3422 _rtld_error("%s: No space available " 3423 "for static Thread Local Storage", obj->path); 3424 result = -1; 3425 } 3426 if (result != -1) 3427 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3428 RTLD_LO_EARLY)); 3429 init_dag(obj); 3430 ref_dag(obj); 3431 if (result != -1) 3432 result = rtld_verify_versions(&obj->dagmembers); 3433 if (result != -1 && ld_tracing) 3434 goto trace; 3435 if (result == -1 || relocate_object_dag(obj, 3436 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3437 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3438 lockstate) == -1) { 3439 dlopen_cleanup(obj, lockstate); 3440 obj = NULL; 3441 } else if (lo_flags & RTLD_LO_EARLY) { 3442 /* 3443 * Do not call the init functions for early loaded 3444 * filtees. The image is still not initialized enough 3445 * for them to work. 3446 * 3447 * Our object is found by the global object list and 3448 * will be ordered among all init calls done right 3449 * before transferring control to main. 3450 */ 3451 } else { 3452 /* Make list of init functions to call. */ 3453 initlist_add_objects(obj, obj, &initlist); 3454 } 3455 /* 3456 * Process all no_delete or global objects here, given 3457 * them own DAGs to prevent their dependencies from being 3458 * unloaded. This has to be done after we have loaded all 3459 * of the dependencies, so that we do not miss any. 3460 */ 3461 if (obj != NULL) 3462 process_z(obj); 3463 } else { 3464 /* 3465 * Bump the reference counts for objects on this DAG. If 3466 * this is the first dlopen() call for the object that was 3467 * already loaded as a dependency, initialize the dag 3468 * starting at it. 3469 */ 3470 init_dag(obj); 3471 ref_dag(obj); 3472 3473 if ((lo_flags & RTLD_LO_TRACE) != 0) 3474 goto trace; 3475 } 3476 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3477 obj->z_nodelete) && !obj->ref_nodel) { 3478 dbg("obj %s nodelete", obj->path); 3479 ref_dag(obj); 3480 obj->z_nodelete = obj->ref_nodel = true; 3481 } 3482 } 3483 3484 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3485 name); 3486 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3487 3488 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3489 map_stacks_exec(lockstate); 3490 if (obj != NULL) 3491 distribute_static_tls(&initlist, lockstate); 3492 } 3493 3494 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3495 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3496 lockstate) == -1) { 3497 objlist_clear(&initlist); 3498 dlopen_cleanup(obj, lockstate); 3499 if (lockstate == &mlockstate) 3500 lock_release(rtld_bind_lock, lockstate); 3501 return (NULL); 3502 } 3503 3504 if (!(lo_flags & RTLD_LO_EARLY)) { 3505 /* Call the init functions. */ 3506 objlist_call_init(&initlist, lockstate); 3507 } 3508 objlist_clear(&initlist); 3509 if (lockstate == &mlockstate) 3510 lock_release(rtld_bind_lock, lockstate); 3511 return obj; 3512 trace: 3513 trace_loaded_objects(obj); 3514 if (lockstate == &mlockstate) 3515 lock_release(rtld_bind_lock, lockstate); 3516 exit(0); 3517 } 3518 3519 static void * 3520 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3521 int flags) 3522 { 3523 DoneList donelist; 3524 const Obj_Entry *obj, *defobj; 3525 const Elf_Sym *def; 3526 SymLook req; 3527 RtldLockState lockstate; 3528 tls_index ti; 3529 void *sym; 3530 int res; 3531 3532 def = NULL; 3533 defobj = NULL; 3534 symlook_init(&req, name); 3535 req.ventry = ve; 3536 req.flags = flags | SYMLOOK_IN_PLT; 3537 req.lockstate = &lockstate; 3538 3539 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3540 rlock_acquire(rtld_bind_lock, &lockstate); 3541 if (sigsetjmp(lockstate.env, 0) != 0) 3542 lock_upgrade(rtld_bind_lock, &lockstate); 3543 if (handle == NULL || handle == RTLD_NEXT || 3544 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3545 3546 if ((obj = obj_from_addr(retaddr)) == NULL) { 3547 _rtld_error("Cannot determine caller's shared object"); 3548 lock_release(rtld_bind_lock, &lockstate); 3549 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3550 return NULL; 3551 } 3552 if (handle == NULL) { /* Just the caller's shared object. */ 3553 res = symlook_obj(&req, obj); 3554 if (res == 0) { 3555 def = req.sym_out; 3556 defobj = req.defobj_out; 3557 } 3558 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3559 handle == RTLD_SELF) { /* ... caller included */ 3560 if (handle == RTLD_NEXT) 3561 obj = globallist_next(obj); 3562 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3563 if (obj->marker) 3564 continue; 3565 res = symlook_obj(&req, obj); 3566 if (res == 0) { 3567 if (def == NULL || 3568 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3569 def = req.sym_out; 3570 defobj = req.defobj_out; 3571 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3572 break; 3573 } 3574 } 3575 } 3576 /* 3577 * Search the dynamic linker itself, and possibly resolve the 3578 * symbol from there. This is how the application links to 3579 * dynamic linker services such as dlopen. 3580 */ 3581 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3582 res = symlook_obj(&req, &obj_rtld); 3583 if (res == 0) { 3584 def = req.sym_out; 3585 defobj = req.defobj_out; 3586 } 3587 } 3588 } else { 3589 assert(handle == RTLD_DEFAULT); 3590 res = symlook_default(&req, obj); 3591 if (res == 0) { 3592 defobj = req.defobj_out; 3593 def = req.sym_out; 3594 } 3595 } 3596 } else { 3597 if ((obj = dlcheck(handle)) == NULL) { 3598 lock_release(rtld_bind_lock, &lockstate); 3599 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3600 return NULL; 3601 } 3602 3603 donelist_init(&donelist); 3604 if (obj->mainprog) { 3605 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3606 res = symlook_global(&req, &donelist); 3607 if (res == 0) { 3608 def = req.sym_out; 3609 defobj = req.defobj_out; 3610 } 3611 /* 3612 * Search the dynamic linker itself, and possibly resolve the 3613 * symbol from there. This is how the application links to 3614 * dynamic linker services such as dlopen. 3615 */ 3616 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3617 res = symlook_obj(&req, &obj_rtld); 3618 if (res == 0) { 3619 def = req.sym_out; 3620 defobj = req.defobj_out; 3621 } 3622 } 3623 } 3624 else { 3625 /* Search the whole DAG rooted at the given object. */ 3626 res = symlook_list(&req, &obj->dagmembers, &donelist); 3627 if (res == 0) { 3628 def = req.sym_out; 3629 defobj = req.defobj_out; 3630 } 3631 } 3632 } 3633 3634 if (def != NULL) { 3635 lock_release(rtld_bind_lock, &lockstate); 3636 3637 /* 3638 * The value required by the caller is derived from the value 3639 * of the symbol. this is simply the relocated value of the 3640 * symbol. 3641 */ 3642 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3643 sym = make_function_pointer(def, defobj); 3644 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3645 sym = rtld_resolve_ifunc(defobj, def); 3646 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3647 ti.ti_module = defobj->tlsindex; 3648 ti.ti_offset = def->st_value; 3649 sym = __tls_get_addr(&ti); 3650 } else 3651 sym = defobj->relocbase + def->st_value; 3652 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3653 return (sym); 3654 } 3655 3656 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3657 ve != NULL ? ve->name : ""); 3658 lock_release(rtld_bind_lock, &lockstate); 3659 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3660 return NULL; 3661 } 3662 3663 void * 3664 dlsym(void *handle, const char *name) 3665 { 3666 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3667 SYMLOOK_DLSYM); 3668 } 3669 3670 dlfunc_t 3671 dlfunc(void *handle, const char *name) 3672 { 3673 union { 3674 void *d; 3675 dlfunc_t f; 3676 } rv; 3677 3678 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3679 SYMLOOK_DLSYM); 3680 return (rv.f); 3681 } 3682 3683 void * 3684 dlvsym(void *handle, const char *name, const char *version) 3685 { 3686 Ver_Entry ventry; 3687 3688 ventry.name = version; 3689 ventry.file = NULL; 3690 ventry.hash = elf_hash(version); 3691 ventry.flags= 0; 3692 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3693 SYMLOOK_DLSYM); 3694 } 3695 3696 int 3697 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3698 { 3699 const Obj_Entry *obj; 3700 RtldLockState lockstate; 3701 3702 rlock_acquire(rtld_bind_lock, &lockstate); 3703 obj = obj_from_addr(addr); 3704 if (obj == NULL) { 3705 _rtld_error("No shared object contains address"); 3706 lock_release(rtld_bind_lock, &lockstate); 3707 return (0); 3708 } 3709 rtld_fill_dl_phdr_info(obj, phdr_info); 3710 lock_release(rtld_bind_lock, &lockstate); 3711 return (1); 3712 } 3713 3714 int 3715 dladdr(const void *addr, Dl_info *info) 3716 { 3717 const Obj_Entry *obj; 3718 const Elf_Sym *def; 3719 void *symbol_addr; 3720 unsigned long symoffset; 3721 RtldLockState lockstate; 3722 3723 rlock_acquire(rtld_bind_lock, &lockstate); 3724 obj = obj_from_addr(addr); 3725 if (obj == NULL) { 3726 _rtld_error("No shared object contains address"); 3727 lock_release(rtld_bind_lock, &lockstate); 3728 return 0; 3729 } 3730 info->dli_fname = obj->path; 3731 info->dli_fbase = obj->mapbase; 3732 info->dli_saddr = (void *)0; 3733 info->dli_sname = NULL; 3734 3735 /* 3736 * Walk the symbol list looking for the symbol whose address is 3737 * closest to the address sent in. 3738 */ 3739 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3740 def = obj->symtab + symoffset; 3741 3742 /* 3743 * For skip the symbol if st_shndx is either SHN_UNDEF or 3744 * SHN_COMMON. 3745 */ 3746 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3747 continue; 3748 3749 /* 3750 * If the symbol is greater than the specified address, or if it 3751 * is further away from addr than the current nearest symbol, 3752 * then reject it. 3753 */ 3754 symbol_addr = obj->relocbase + def->st_value; 3755 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3756 continue; 3757 3758 /* Update our idea of the nearest symbol. */ 3759 info->dli_sname = obj->strtab + def->st_name; 3760 info->dli_saddr = symbol_addr; 3761 3762 /* Exact match? */ 3763 if (info->dli_saddr == addr) 3764 break; 3765 } 3766 lock_release(rtld_bind_lock, &lockstate); 3767 return 1; 3768 } 3769 3770 int 3771 dlinfo(void *handle, int request, void *p) 3772 { 3773 const Obj_Entry *obj; 3774 RtldLockState lockstate; 3775 int error; 3776 3777 rlock_acquire(rtld_bind_lock, &lockstate); 3778 3779 if (handle == NULL || handle == RTLD_SELF) { 3780 void *retaddr; 3781 3782 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3783 if ((obj = obj_from_addr(retaddr)) == NULL) 3784 _rtld_error("Cannot determine caller's shared object"); 3785 } else 3786 obj = dlcheck(handle); 3787 3788 if (obj == NULL) { 3789 lock_release(rtld_bind_lock, &lockstate); 3790 return (-1); 3791 } 3792 3793 error = 0; 3794 switch (request) { 3795 case RTLD_DI_LINKMAP: 3796 *((struct link_map const **)p) = &obj->linkmap; 3797 break; 3798 case RTLD_DI_ORIGIN: 3799 error = rtld_dirname(obj->path, p); 3800 break; 3801 3802 case RTLD_DI_SERINFOSIZE: 3803 case RTLD_DI_SERINFO: 3804 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3805 break; 3806 3807 default: 3808 _rtld_error("Invalid request %d passed to dlinfo()", request); 3809 error = -1; 3810 } 3811 3812 lock_release(rtld_bind_lock, &lockstate); 3813 3814 return (error); 3815 } 3816 3817 static void 3818 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3819 { 3820 3821 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3822 phdr_info->dlpi_name = obj->path; 3823 phdr_info->dlpi_phdr = obj->phdr; 3824 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3825 phdr_info->dlpi_tls_modid = obj->tlsindex; 3826 phdr_info->dlpi_tls_data = obj->tlsinit; 3827 phdr_info->dlpi_adds = obj_loads; 3828 phdr_info->dlpi_subs = obj_loads - obj_count; 3829 } 3830 3831 int 3832 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3833 { 3834 struct dl_phdr_info phdr_info; 3835 Obj_Entry *obj, marker; 3836 RtldLockState bind_lockstate, phdr_lockstate; 3837 int error; 3838 3839 init_marker(&marker); 3840 error = 0; 3841 3842 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3843 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3844 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3845 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3846 rtld_fill_dl_phdr_info(obj, &phdr_info); 3847 hold_object(obj); 3848 lock_release(rtld_bind_lock, &bind_lockstate); 3849 3850 error = callback(&phdr_info, sizeof phdr_info, param); 3851 3852 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3853 unhold_object(obj); 3854 obj = globallist_next(&marker); 3855 TAILQ_REMOVE(&obj_list, &marker, next); 3856 if (error != 0) { 3857 lock_release(rtld_bind_lock, &bind_lockstate); 3858 lock_release(rtld_phdr_lock, &phdr_lockstate); 3859 return (error); 3860 } 3861 } 3862 3863 if (error == 0) { 3864 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3865 lock_release(rtld_bind_lock, &bind_lockstate); 3866 error = callback(&phdr_info, sizeof(phdr_info), param); 3867 } 3868 lock_release(rtld_phdr_lock, &phdr_lockstate); 3869 return (error); 3870 } 3871 3872 static void * 3873 fill_search_info(const char *dir, size_t dirlen, void *param) 3874 { 3875 struct fill_search_info_args *arg; 3876 3877 arg = param; 3878 3879 if (arg->request == RTLD_DI_SERINFOSIZE) { 3880 arg->serinfo->dls_cnt ++; 3881 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3882 } else { 3883 struct dl_serpath *s_entry; 3884 3885 s_entry = arg->serpath; 3886 s_entry->dls_name = arg->strspace; 3887 s_entry->dls_flags = arg->flags; 3888 3889 strncpy(arg->strspace, dir, dirlen); 3890 arg->strspace[dirlen] = '\0'; 3891 3892 arg->strspace += dirlen + 1; 3893 arg->serpath++; 3894 } 3895 3896 return (NULL); 3897 } 3898 3899 static int 3900 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3901 { 3902 struct dl_serinfo _info; 3903 struct fill_search_info_args args; 3904 3905 args.request = RTLD_DI_SERINFOSIZE; 3906 args.serinfo = &_info; 3907 3908 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3909 _info.dls_cnt = 0; 3910 3911 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3912 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3913 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3914 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3915 if (!obj->z_nodeflib) 3916 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3917 3918 3919 if (request == RTLD_DI_SERINFOSIZE) { 3920 info->dls_size = _info.dls_size; 3921 info->dls_cnt = _info.dls_cnt; 3922 return (0); 3923 } 3924 3925 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3926 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3927 return (-1); 3928 } 3929 3930 args.request = RTLD_DI_SERINFO; 3931 args.serinfo = info; 3932 args.serpath = &info->dls_serpath[0]; 3933 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3934 3935 args.flags = LA_SER_RUNPATH; 3936 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3937 return (-1); 3938 3939 args.flags = LA_SER_LIBPATH; 3940 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3941 return (-1); 3942 3943 args.flags = LA_SER_RUNPATH; 3944 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3945 return (-1); 3946 3947 args.flags = LA_SER_CONFIG; 3948 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3949 != NULL) 3950 return (-1); 3951 3952 args.flags = LA_SER_DEFAULT; 3953 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3954 fill_search_info, NULL, &args) != NULL) 3955 return (-1); 3956 return (0); 3957 } 3958 3959 static int 3960 rtld_dirname(const char *path, char *bname) 3961 { 3962 const char *endp; 3963 3964 /* Empty or NULL string gets treated as "." */ 3965 if (path == NULL || *path == '\0') { 3966 bname[0] = '.'; 3967 bname[1] = '\0'; 3968 return (0); 3969 } 3970 3971 /* Strip trailing slashes */ 3972 endp = path + strlen(path) - 1; 3973 while (endp > path && *endp == '/') 3974 endp--; 3975 3976 /* Find the start of the dir */ 3977 while (endp > path && *endp != '/') 3978 endp--; 3979 3980 /* Either the dir is "/" or there are no slashes */ 3981 if (endp == path) { 3982 bname[0] = *endp == '/' ? '/' : '.'; 3983 bname[1] = '\0'; 3984 return (0); 3985 } else { 3986 do { 3987 endp--; 3988 } while (endp > path && *endp == '/'); 3989 } 3990 3991 if (endp - path + 2 > PATH_MAX) 3992 { 3993 _rtld_error("Filename is too long: %s", path); 3994 return(-1); 3995 } 3996 3997 strncpy(bname, path, endp - path + 1); 3998 bname[endp - path + 1] = '\0'; 3999 return (0); 4000 } 4001 4002 static int 4003 rtld_dirname_abs(const char *path, char *base) 4004 { 4005 char *last; 4006 4007 if (realpath(path, base) == NULL) { 4008 _rtld_error("realpath \"%s\" failed (%s)", path, 4009 rtld_strerror(errno)); 4010 return (-1); 4011 } 4012 dbg("%s -> %s", path, base); 4013 last = strrchr(base, '/'); 4014 if (last == NULL) { 4015 _rtld_error("non-abs result from realpath \"%s\"", path); 4016 return (-1); 4017 } 4018 if (last != base) 4019 *last = '\0'; 4020 return (0); 4021 } 4022 4023 static void 4024 linkmap_add(Obj_Entry *obj) 4025 { 4026 struct link_map *l = &obj->linkmap; 4027 struct link_map *prev; 4028 4029 obj->linkmap.l_name = obj->path; 4030 obj->linkmap.l_addr = obj->mapbase; 4031 obj->linkmap.l_ld = obj->dynamic; 4032 #ifdef __mips__ 4033 /* GDB needs load offset on MIPS to use the symbols */ 4034 obj->linkmap.l_offs = obj->relocbase; 4035 #endif 4036 4037 if (r_debug.r_map == NULL) { 4038 r_debug.r_map = l; 4039 return; 4040 } 4041 4042 /* 4043 * Scan to the end of the list, but not past the entry for the 4044 * dynamic linker, which we want to keep at the very end. 4045 */ 4046 for (prev = r_debug.r_map; 4047 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4048 prev = prev->l_next) 4049 ; 4050 4051 /* Link in the new entry. */ 4052 l->l_prev = prev; 4053 l->l_next = prev->l_next; 4054 if (l->l_next != NULL) 4055 l->l_next->l_prev = l; 4056 prev->l_next = l; 4057 } 4058 4059 static void 4060 linkmap_delete(Obj_Entry *obj) 4061 { 4062 struct link_map *l = &obj->linkmap; 4063 4064 if (l->l_prev == NULL) { 4065 if ((r_debug.r_map = l->l_next) != NULL) 4066 l->l_next->l_prev = NULL; 4067 return; 4068 } 4069 4070 if ((l->l_prev->l_next = l->l_next) != NULL) 4071 l->l_next->l_prev = l->l_prev; 4072 } 4073 4074 /* 4075 * Function for the debugger to set a breakpoint on to gain control. 4076 * 4077 * The two parameters allow the debugger to easily find and determine 4078 * what the runtime loader is doing and to whom it is doing it. 4079 * 4080 * When the loadhook trap is hit (r_debug_state, set at program 4081 * initialization), the arguments can be found on the stack: 4082 * 4083 * +8 struct link_map *m 4084 * +4 struct r_debug *rd 4085 * +0 RetAddr 4086 */ 4087 void 4088 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4089 { 4090 /* 4091 * The following is a hack to force the compiler to emit calls to 4092 * this function, even when optimizing. If the function is empty, 4093 * the compiler is not obliged to emit any code for calls to it, 4094 * even when marked __noinline. However, gdb depends on those 4095 * calls being made. 4096 */ 4097 __compiler_membar(); 4098 } 4099 4100 /* 4101 * A function called after init routines have completed. This can be used to 4102 * break before a program's entry routine is called, and can be used when 4103 * main is not available in the symbol table. 4104 */ 4105 void 4106 _r_debug_postinit(struct link_map *m __unused) 4107 { 4108 4109 /* See r_debug_state(). */ 4110 __compiler_membar(); 4111 } 4112 4113 static void 4114 release_object(Obj_Entry *obj) 4115 { 4116 4117 if (obj->holdcount > 0) { 4118 obj->unholdfree = true; 4119 return; 4120 } 4121 munmap(obj->mapbase, obj->mapsize); 4122 linkmap_delete(obj); 4123 obj_free(obj); 4124 } 4125 4126 /* 4127 * Get address of the pointer variable in the main program. 4128 * Prefer non-weak symbol over the weak one. 4129 */ 4130 static const void ** 4131 get_program_var_addr(const char *name, RtldLockState *lockstate) 4132 { 4133 SymLook req; 4134 DoneList donelist; 4135 4136 symlook_init(&req, name); 4137 req.lockstate = lockstate; 4138 donelist_init(&donelist); 4139 if (symlook_global(&req, &donelist) != 0) 4140 return (NULL); 4141 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4142 return ((const void **)make_function_pointer(req.sym_out, 4143 req.defobj_out)); 4144 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4145 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4146 else 4147 return ((const void **)(req.defobj_out->relocbase + 4148 req.sym_out->st_value)); 4149 } 4150 4151 /* 4152 * Set a pointer variable in the main program to the given value. This 4153 * is used to set key variables such as "environ" before any of the 4154 * init functions are called. 4155 */ 4156 static void 4157 set_program_var(const char *name, const void *value) 4158 { 4159 const void **addr; 4160 4161 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4162 dbg("\"%s\": *%p <-- %p", name, addr, value); 4163 *addr = value; 4164 } 4165 } 4166 4167 /* 4168 * Search the global objects, including dependencies and main object, 4169 * for the given symbol. 4170 */ 4171 static int 4172 symlook_global(SymLook *req, DoneList *donelist) 4173 { 4174 SymLook req1; 4175 const Objlist_Entry *elm; 4176 int res; 4177 4178 symlook_init_from_req(&req1, req); 4179 4180 /* Search all objects loaded at program start up. */ 4181 if (req->defobj_out == NULL || 4182 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4183 res = symlook_list(&req1, &list_main, donelist); 4184 if (res == 0 && (req->defobj_out == NULL || 4185 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4186 req->sym_out = req1.sym_out; 4187 req->defobj_out = req1.defobj_out; 4188 assert(req->defobj_out != NULL); 4189 } 4190 } 4191 4192 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4193 STAILQ_FOREACH(elm, &list_global, link) { 4194 if (req->defobj_out != NULL && 4195 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4196 break; 4197 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4198 if (res == 0 && (req->defobj_out == NULL || 4199 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4200 req->sym_out = req1.sym_out; 4201 req->defobj_out = req1.defobj_out; 4202 assert(req->defobj_out != NULL); 4203 } 4204 } 4205 4206 return (req->sym_out != NULL ? 0 : ESRCH); 4207 } 4208 4209 /* 4210 * Given a symbol name in a referencing object, find the corresponding 4211 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4212 * no definition was found. Returns a pointer to the Obj_Entry of the 4213 * defining object via the reference parameter DEFOBJ_OUT. 4214 */ 4215 static int 4216 symlook_default(SymLook *req, const Obj_Entry *refobj) 4217 { 4218 DoneList donelist; 4219 const Objlist_Entry *elm; 4220 SymLook req1; 4221 int res; 4222 4223 donelist_init(&donelist); 4224 symlook_init_from_req(&req1, req); 4225 4226 /* 4227 * Look first in the referencing object if linked symbolically, 4228 * and similarly handle protected symbols. 4229 */ 4230 res = symlook_obj(&req1, refobj); 4231 if (res == 0 && (refobj->symbolic || 4232 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4233 req->sym_out = req1.sym_out; 4234 req->defobj_out = req1.defobj_out; 4235 assert(req->defobj_out != NULL); 4236 } 4237 if (refobj->symbolic || req->defobj_out != NULL) 4238 donelist_check(&donelist, refobj); 4239 4240 symlook_global(req, &donelist); 4241 4242 /* Search all dlopened DAGs containing the referencing object. */ 4243 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4244 if (req->sym_out != NULL && 4245 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4246 break; 4247 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4248 if (res == 0 && (req->sym_out == NULL || 4249 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4250 req->sym_out = req1.sym_out; 4251 req->defobj_out = req1.defobj_out; 4252 assert(req->defobj_out != NULL); 4253 } 4254 } 4255 4256 /* 4257 * Search the dynamic linker itself, and possibly resolve the 4258 * symbol from there. This is how the application links to 4259 * dynamic linker services such as dlopen. 4260 */ 4261 if (req->sym_out == NULL || 4262 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4263 res = symlook_obj(&req1, &obj_rtld); 4264 if (res == 0) { 4265 req->sym_out = req1.sym_out; 4266 req->defobj_out = req1.defobj_out; 4267 assert(req->defobj_out != NULL); 4268 } 4269 } 4270 4271 return (req->sym_out != NULL ? 0 : ESRCH); 4272 } 4273 4274 static int 4275 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4276 { 4277 const Elf_Sym *def; 4278 const Obj_Entry *defobj; 4279 const Objlist_Entry *elm; 4280 SymLook req1; 4281 int res; 4282 4283 def = NULL; 4284 defobj = NULL; 4285 STAILQ_FOREACH(elm, objlist, link) { 4286 if (donelist_check(dlp, elm->obj)) 4287 continue; 4288 symlook_init_from_req(&req1, req); 4289 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4290 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4291 def = req1.sym_out; 4292 defobj = req1.defobj_out; 4293 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4294 break; 4295 } 4296 } 4297 } 4298 if (def != NULL) { 4299 req->sym_out = def; 4300 req->defobj_out = defobj; 4301 return (0); 4302 } 4303 return (ESRCH); 4304 } 4305 4306 /* 4307 * Search the chain of DAGS cointed to by the given Needed_Entry 4308 * for a symbol of the given name. Each DAG is scanned completely 4309 * before advancing to the next one. Returns a pointer to the symbol, 4310 * or NULL if no definition was found. 4311 */ 4312 static int 4313 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4314 { 4315 const Elf_Sym *def; 4316 const Needed_Entry *n; 4317 const Obj_Entry *defobj; 4318 SymLook req1; 4319 int res; 4320 4321 def = NULL; 4322 defobj = NULL; 4323 symlook_init_from_req(&req1, req); 4324 for (n = needed; n != NULL; n = n->next) { 4325 if (n->obj == NULL || 4326 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4327 continue; 4328 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4329 def = req1.sym_out; 4330 defobj = req1.defobj_out; 4331 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4332 break; 4333 } 4334 } 4335 if (def != NULL) { 4336 req->sym_out = def; 4337 req->defobj_out = defobj; 4338 return (0); 4339 } 4340 return (ESRCH); 4341 } 4342 4343 /* 4344 * Search the symbol table of a single shared object for a symbol of 4345 * the given name and version, if requested. Returns a pointer to the 4346 * symbol, or NULL if no definition was found. If the object is 4347 * filter, return filtered symbol from filtee. 4348 * 4349 * The symbol's hash value is passed in for efficiency reasons; that 4350 * eliminates many recomputations of the hash value. 4351 */ 4352 int 4353 symlook_obj(SymLook *req, const Obj_Entry *obj) 4354 { 4355 DoneList donelist; 4356 SymLook req1; 4357 int flags, res, mres; 4358 4359 /* 4360 * If there is at least one valid hash at this point, we prefer to 4361 * use the faster GNU version if available. 4362 */ 4363 if (obj->valid_hash_gnu) 4364 mres = symlook_obj1_gnu(req, obj); 4365 else if (obj->valid_hash_sysv) 4366 mres = symlook_obj1_sysv(req, obj); 4367 else 4368 return (EINVAL); 4369 4370 if (mres == 0) { 4371 if (obj->needed_filtees != NULL) { 4372 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4373 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4374 donelist_init(&donelist); 4375 symlook_init_from_req(&req1, req); 4376 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4377 if (res == 0) { 4378 req->sym_out = req1.sym_out; 4379 req->defobj_out = req1.defobj_out; 4380 } 4381 return (res); 4382 } 4383 if (obj->needed_aux_filtees != NULL) { 4384 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4385 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4386 donelist_init(&donelist); 4387 symlook_init_from_req(&req1, req); 4388 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4389 if (res == 0) { 4390 req->sym_out = req1.sym_out; 4391 req->defobj_out = req1.defobj_out; 4392 return (res); 4393 } 4394 } 4395 } 4396 return (mres); 4397 } 4398 4399 /* Symbol match routine common to both hash functions */ 4400 static bool 4401 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4402 const unsigned long symnum) 4403 { 4404 Elf_Versym verndx; 4405 const Elf_Sym *symp; 4406 const char *strp; 4407 4408 symp = obj->symtab + symnum; 4409 strp = obj->strtab + symp->st_name; 4410 4411 switch (ELF_ST_TYPE(symp->st_info)) { 4412 case STT_FUNC: 4413 case STT_NOTYPE: 4414 case STT_OBJECT: 4415 case STT_COMMON: 4416 case STT_GNU_IFUNC: 4417 if (symp->st_value == 0) 4418 return (false); 4419 /* fallthrough */ 4420 case STT_TLS: 4421 if (symp->st_shndx != SHN_UNDEF) 4422 break; 4423 #ifndef __mips__ 4424 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4425 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4426 break; 4427 #endif 4428 /* fallthrough */ 4429 default: 4430 return (false); 4431 } 4432 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4433 return (false); 4434 4435 if (req->ventry == NULL) { 4436 if (obj->versyms != NULL) { 4437 verndx = VER_NDX(obj->versyms[symnum]); 4438 if (verndx > obj->vernum) { 4439 _rtld_error( 4440 "%s: symbol %s references wrong version %d", 4441 obj->path, obj->strtab + symnum, verndx); 4442 return (false); 4443 } 4444 /* 4445 * If we are not called from dlsym (i.e. this 4446 * is a normal relocation from unversioned 4447 * binary), accept the symbol immediately if 4448 * it happens to have first version after this 4449 * shared object became versioned. Otherwise, 4450 * if symbol is versioned and not hidden, 4451 * remember it. If it is the only symbol with 4452 * this name exported by the shared object, it 4453 * will be returned as a match by the calling 4454 * function. If symbol is global (verndx < 2) 4455 * accept it unconditionally. 4456 */ 4457 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4458 verndx == VER_NDX_GIVEN) { 4459 result->sym_out = symp; 4460 return (true); 4461 } 4462 else if (verndx >= VER_NDX_GIVEN) { 4463 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4464 == 0) { 4465 if (result->vsymp == NULL) 4466 result->vsymp = symp; 4467 result->vcount++; 4468 } 4469 return (false); 4470 } 4471 } 4472 result->sym_out = symp; 4473 return (true); 4474 } 4475 if (obj->versyms == NULL) { 4476 if (object_match_name(obj, req->ventry->name)) { 4477 _rtld_error("%s: object %s should provide version %s " 4478 "for symbol %s", obj_rtld.path, obj->path, 4479 req->ventry->name, obj->strtab + symnum); 4480 return (false); 4481 } 4482 } else { 4483 verndx = VER_NDX(obj->versyms[symnum]); 4484 if (verndx > obj->vernum) { 4485 _rtld_error("%s: symbol %s references wrong version %d", 4486 obj->path, obj->strtab + symnum, verndx); 4487 return (false); 4488 } 4489 if (obj->vertab[verndx].hash != req->ventry->hash || 4490 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4491 /* 4492 * Version does not match. Look if this is a 4493 * global symbol and if it is not hidden. If 4494 * global symbol (verndx < 2) is available, 4495 * use it. Do not return symbol if we are 4496 * called by dlvsym, because dlvsym looks for 4497 * a specific version and default one is not 4498 * what dlvsym wants. 4499 */ 4500 if ((req->flags & SYMLOOK_DLSYM) || 4501 (verndx >= VER_NDX_GIVEN) || 4502 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4503 return (false); 4504 } 4505 } 4506 result->sym_out = symp; 4507 return (true); 4508 } 4509 4510 /* 4511 * Search for symbol using SysV hash function. 4512 * obj->buckets is known not to be NULL at this point; the test for this was 4513 * performed with the obj->valid_hash_sysv assignment. 4514 */ 4515 static int 4516 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4517 { 4518 unsigned long symnum; 4519 Sym_Match_Result matchres; 4520 4521 matchres.sym_out = NULL; 4522 matchres.vsymp = NULL; 4523 matchres.vcount = 0; 4524 4525 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4526 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4527 if (symnum >= obj->nchains) 4528 return (ESRCH); /* Bad object */ 4529 4530 if (matched_symbol(req, obj, &matchres, symnum)) { 4531 req->sym_out = matchres.sym_out; 4532 req->defobj_out = obj; 4533 return (0); 4534 } 4535 } 4536 if (matchres.vcount == 1) { 4537 req->sym_out = matchres.vsymp; 4538 req->defobj_out = obj; 4539 return (0); 4540 } 4541 return (ESRCH); 4542 } 4543 4544 /* Search for symbol using GNU hash function */ 4545 static int 4546 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4547 { 4548 Elf_Addr bloom_word; 4549 const Elf32_Word *hashval; 4550 Elf32_Word bucket; 4551 Sym_Match_Result matchres; 4552 unsigned int h1, h2; 4553 unsigned long symnum; 4554 4555 matchres.sym_out = NULL; 4556 matchres.vsymp = NULL; 4557 matchres.vcount = 0; 4558 4559 /* Pick right bitmask word from Bloom filter array */ 4560 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4561 obj->maskwords_bm_gnu]; 4562 4563 /* Calculate modulus word size of gnu hash and its derivative */ 4564 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4565 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4566 4567 /* Filter out the "definitely not in set" queries */ 4568 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4569 return (ESRCH); 4570 4571 /* Locate hash chain and corresponding value element*/ 4572 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4573 if (bucket == 0) 4574 return (ESRCH); 4575 hashval = &obj->chain_zero_gnu[bucket]; 4576 do { 4577 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4578 symnum = hashval - obj->chain_zero_gnu; 4579 if (matched_symbol(req, obj, &matchres, symnum)) { 4580 req->sym_out = matchres.sym_out; 4581 req->defobj_out = obj; 4582 return (0); 4583 } 4584 } 4585 } while ((*hashval++ & 1) == 0); 4586 if (matchres.vcount == 1) { 4587 req->sym_out = matchres.vsymp; 4588 req->defobj_out = obj; 4589 return (0); 4590 } 4591 return (ESRCH); 4592 } 4593 4594 static void 4595 trace_loaded_objects(Obj_Entry *obj) 4596 { 4597 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4598 int c; 4599 4600 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4601 main_local = ""; 4602 4603 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4604 fmt1 = "\t%o => %p (%x)\n"; 4605 4606 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4607 fmt2 = "\t%o (%x)\n"; 4608 4609 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4610 4611 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4612 Needed_Entry *needed; 4613 const char *name, *path; 4614 bool is_lib; 4615 4616 if (obj->marker) 4617 continue; 4618 if (list_containers && obj->needed != NULL) 4619 rtld_printf("%s:\n", obj->path); 4620 for (needed = obj->needed; needed; needed = needed->next) { 4621 if (needed->obj != NULL) { 4622 if (needed->obj->traced && !list_containers) 4623 continue; 4624 needed->obj->traced = true; 4625 path = needed->obj->path; 4626 } else 4627 path = "not found"; 4628 4629 name = obj->strtab + needed->name; 4630 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4631 4632 fmt = is_lib ? fmt1 : fmt2; 4633 while ((c = *fmt++) != '\0') { 4634 switch (c) { 4635 default: 4636 rtld_putchar(c); 4637 continue; 4638 case '\\': 4639 switch (c = *fmt) { 4640 case '\0': 4641 continue; 4642 case 'n': 4643 rtld_putchar('\n'); 4644 break; 4645 case 't': 4646 rtld_putchar('\t'); 4647 break; 4648 } 4649 break; 4650 case '%': 4651 switch (c = *fmt) { 4652 case '\0': 4653 continue; 4654 case '%': 4655 default: 4656 rtld_putchar(c); 4657 break; 4658 case 'A': 4659 rtld_putstr(main_local); 4660 break; 4661 case 'a': 4662 rtld_putstr(obj_main->path); 4663 break; 4664 case 'o': 4665 rtld_putstr(name); 4666 break; 4667 #if 0 4668 case 'm': 4669 rtld_printf("%d", sodp->sod_major); 4670 break; 4671 case 'n': 4672 rtld_printf("%d", sodp->sod_minor); 4673 break; 4674 #endif 4675 case 'p': 4676 rtld_putstr(path); 4677 break; 4678 case 'x': 4679 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4680 0); 4681 break; 4682 } 4683 break; 4684 } 4685 ++fmt; 4686 } 4687 } 4688 } 4689 } 4690 4691 /* 4692 * Unload a dlopened object and its dependencies from memory and from 4693 * our data structures. It is assumed that the DAG rooted in the 4694 * object has already been unreferenced, and that the object has a 4695 * reference count of 0. 4696 */ 4697 static void 4698 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4699 { 4700 Obj_Entry marker, *obj, *next; 4701 4702 assert(root->refcount == 0); 4703 4704 /* 4705 * Pass over the DAG removing unreferenced objects from 4706 * appropriate lists. 4707 */ 4708 unlink_object(root); 4709 4710 /* Unmap all objects that are no longer referenced. */ 4711 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4712 next = TAILQ_NEXT(obj, next); 4713 if (obj->marker || obj->refcount != 0) 4714 continue; 4715 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4716 obj->mapsize, 0, obj->path); 4717 dbg("unloading \"%s\"", obj->path); 4718 /* 4719 * Unlink the object now to prevent new references from 4720 * being acquired while the bind lock is dropped in 4721 * recursive dlclose() invocations. 4722 */ 4723 TAILQ_REMOVE(&obj_list, obj, next); 4724 obj_count--; 4725 4726 if (obj->filtees_loaded) { 4727 if (next != NULL) { 4728 init_marker(&marker); 4729 TAILQ_INSERT_BEFORE(next, &marker, next); 4730 unload_filtees(obj, lockstate); 4731 next = TAILQ_NEXT(&marker, next); 4732 TAILQ_REMOVE(&obj_list, &marker, next); 4733 } else 4734 unload_filtees(obj, lockstate); 4735 } 4736 release_object(obj); 4737 } 4738 } 4739 4740 static void 4741 unlink_object(Obj_Entry *root) 4742 { 4743 Objlist_Entry *elm; 4744 4745 if (root->refcount == 0) { 4746 /* Remove the object from the RTLD_GLOBAL list. */ 4747 objlist_remove(&list_global, root); 4748 4749 /* Remove the object from all objects' DAG lists. */ 4750 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4751 objlist_remove(&elm->obj->dldags, root); 4752 if (elm->obj != root) 4753 unlink_object(elm->obj); 4754 } 4755 } 4756 } 4757 4758 static void 4759 ref_dag(Obj_Entry *root) 4760 { 4761 Objlist_Entry *elm; 4762 4763 assert(root->dag_inited); 4764 STAILQ_FOREACH(elm, &root->dagmembers, link) 4765 elm->obj->refcount++; 4766 } 4767 4768 static void 4769 unref_dag(Obj_Entry *root) 4770 { 4771 Objlist_Entry *elm; 4772 4773 assert(root->dag_inited); 4774 STAILQ_FOREACH(elm, &root->dagmembers, link) 4775 elm->obj->refcount--; 4776 } 4777 4778 /* 4779 * Common code for MD __tls_get_addr(). 4780 */ 4781 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4782 static void * 4783 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4784 { 4785 Elf_Addr *newdtv, *dtv; 4786 RtldLockState lockstate; 4787 int to_copy; 4788 4789 dtv = *dtvp; 4790 /* Check dtv generation in case new modules have arrived */ 4791 if (dtv[0] != tls_dtv_generation) { 4792 wlock_acquire(rtld_bind_lock, &lockstate); 4793 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4794 to_copy = dtv[1]; 4795 if (to_copy > tls_max_index) 4796 to_copy = tls_max_index; 4797 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4798 newdtv[0] = tls_dtv_generation; 4799 newdtv[1] = tls_max_index; 4800 free(dtv); 4801 lock_release(rtld_bind_lock, &lockstate); 4802 dtv = *dtvp = newdtv; 4803 } 4804 4805 /* Dynamically allocate module TLS if necessary */ 4806 if (dtv[index + 1] == 0) { 4807 /* Signal safe, wlock will block out signals. */ 4808 wlock_acquire(rtld_bind_lock, &lockstate); 4809 if (!dtv[index + 1]) 4810 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4811 lock_release(rtld_bind_lock, &lockstate); 4812 } 4813 return ((void *)(dtv[index + 1] + offset)); 4814 } 4815 4816 void * 4817 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4818 { 4819 Elf_Addr *dtv; 4820 4821 dtv = *dtvp; 4822 /* Check dtv generation in case new modules have arrived */ 4823 if (__predict_true(dtv[0] == tls_dtv_generation && 4824 dtv[index + 1] != 0)) 4825 return ((void *)(dtv[index + 1] + offset)); 4826 return (tls_get_addr_slow(dtvp, index, offset)); 4827 } 4828 4829 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4830 defined(__powerpc__) || defined(__riscv) 4831 4832 /* 4833 * Return pointer to allocated TLS block 4834 */ 4835 static void * 4836 get_tls_block_ptr(void *tcb, size_t tcbsize) 4837 { 4838 size_t extra_size, post_size, pre_size, tls_block_size; 4839 size_t tls_init_align; 4840 4841 tls_init_align = MAX(obj_main->tlsalign, 1); 4842 4843 /* Compute fragments sizes. */ 4844 extra_size = tcbsize - TLS_TCB_SIZE; 4845 post_size = calculate_tls_post_size(tls_init_align); 4846 tls_block_size = tcbsize + post_size; 4847 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4848 4849 return ((char *)tcb - pre_size - extra_size); 4850 } 4851 4852 /* 4853 * Allocate Static TLS using the Variant I method. 4854 * 4855 * For details on the layout, see lib/libc/gen/tls.c. 4856 * 4857 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4858 * it is based on tls_last_offset, and TLS offsets here are really TCB 4859 * offsets, whereas libc's tls_static_space is just the executable's static 4860 * TLS segment. 4861 */ 4862 void * 4863 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4864 { 4865 Obj_Entry *obj; 4866 char *tls_block; 4867 Elf_Addr *dtv, **tcb; 4868 Elf_Addr addr; 4869 Elf_Addr i; 4870 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4871 size_t tls_init_align; 4872 4873 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4874 return (oldtcb); 4875 4876 assert(tcbsize >= TLS_TCB_SIZE); 4877 maxalign = MAX(tcbalign, tls_static_max_align); 4878 tls_init_align = MAX(obj_main->tlsalign, 1); 4879 4880 /* Compute fragmets sizes. */ 4881 extra_size = tcbsize - TLS_TCB_SIZE; 4882 post_size = calculate_tls_post_size(tls_init_align); 4883 tls_block_size = tcbsize + post_size; 4884 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4885 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4886 4887 /* Allocate whole TLS block */ 4888 tls_block = malloc_aligned(tls_block_size, maxalign); 4889 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4890 4891 if (oldtcb != NULL) { 4892 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4893 tls_static_space); 4894 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4895 4896 /* Adjust the DTV. */ 4897 dtv = tcb[0]; 4898 for (i = 0; i < dtv[1]; i++) { 4899 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4900 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4901 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4902 } 4903 } 4904 } else { 4905 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4906 tcb[0] = dtv; 4907 dtv[0] = tls_dtv_generation; 4908 dtv[1] = tls_max_index; 4909 4910 for (obj = globallist_curr(objs); obj != NULL; 4911 obj = globallist_next(obj)) { 4912 if (obj->tlsoffset > 0) { 4913 addr = (Elf_Addr)tcb + obj->tlsoffset; 4914 if (obj->tlsinitsize > 0) 4915 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4916 if (obj->tlssize > obj->tlsinitsize) 4917 memset((void*)(addr + obj->tlsinitsize), 0, 4918 obj->tlssize - obj->tlsinitsize); 4919 dtv[obj->tlsindex + 1] = addr; 4920 } 4921 } 4922 } 4923 4924 return (tcb); 4925 } 4926 4927 void 4928 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 4929 { 4930 Elf_Addr *dtv; 4931 Elf_Addr tlsstart, tlsend; 4932 size_t post_size; 4933 size_t dtvsize, i, tls_init_align; 4934 4935 assert(tcbsize >= TLS_TCB_SIZE); 4936 tls_init_align = MAX(obj_main->tlsalign, 1); 4937 4938 /* Compute fragments sizes. */ 4939 post_size = calculate_tls_post_size(tls_init_align); 4940 4941 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 4942 tlsend = (Elf_Addr)tcb + tls_static_space; 4943 4944 dtv = *(Elf_Addr **)tcb; 4945 dtvsize = dtv[1]; 4946 for (i = 0; i < dtvsize; i++) { 4947 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4948 free((void*)dtv[i+2]); 4949 } 4950 } 4951 free(dtv); 4952 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 4953 } 4954 4955 #endif 4956 4957 #if defined(__i386__) || defined(__amd64__) 4958 4959 /* 4960 * Allocate Static TLS using the Variant II method. 4961 */ 4962 void * 4963 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4964 { 4965 Obj_Entry *obj; 4966 size_t size, ralign; 4967 char *tls; 4968 Elf_Addr *dtv, *olddtv; 4969 Elf_Addr segbase, oldsegbase, addr; 4970 size_t i; 4971 4972 ralign = tcbalign; 4973 if (tls_static_max_align > ralign) 4974 ralign = tls_static_max_align; 4975 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4976 4977 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4978 tls = malloc_aligned(size, ralign); 4979 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4980 4981 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4982 ((Elf_Addr*)segbase)[0] = segbase; 4983 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4984 4985 dtv[0] = tls_dtv_generation; 4986 dtv[1] = tls_max_index; 4987 4988 if (oldtls) { 4989 /* 4990 * Copy the static TLS block over whole. 4991 */ 4992 oldsegbase = (Elf_Addr) oldtls; 4993 memcpy((void *)(segbase - tls_static_space), 4994 (const void *)(oldsegbase - tls_static_space), 4995 tls_static_space); 4996 4997 /* 4998 * If any dynamic TLS blocks have been created tls_get_addr(), 4999 * move them over. 5000 */ 5001 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5002 for (i = 0; i < olddtv[1]; i++) { 5003 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5004 dtv[i+2] = olddtv[i+2]; 5005 olddtv[i+2] = 0; 5006 } 5007 } 5008 5009 /* 5010 * We assume that this block was the one we created with 5011 * allocate_initial_tls(). 5012 */ 5013 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5014 } else { 5015 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5016 if (obj->marker || obj->tlsoffset == 0) 5017 continue; 5018 addr = segbase - obj->tlsoffset; 5019 memset((void*)(addr + obj->tlsinitsize), 5020 0, obj->tlssize - obj->tlsinitsize); 5021 if (obj->tlsinit) { 5022 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5023 obj->static_tls_copied = true; 5024 } 5025 dtv[obj->tlsindex + 1] = addr; 5026 } 5027 } 5028 5029 return (void*) segbase; 5030 } 5031 5032 void 5033 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5034 { 5035 Elf_Addr* dtv; 5036 size_t size, ralign; 5037 int dtvsize, i; 5038 Elf_Addr tlsstart, tlsend; 5039 5040 /* 5041 * Figure out the size of the initial TLS block so that we can 5042 * find stuff which ___tls_get_addr() allocated dynamically. 5043 */ 5044 ralign = tcbalign; 5045 if (tls_static_max_align > ralign) 5046 ralign = tls_static_max_align; 5047 size = round(tls_static_space, ralign); 5048 5049 dtv = ((Elf_Addr**)tls)[1]; 5050 dtvsize = dtv[1]; 5051 tlsend = (Elf_Addr) tls; 5052 tlsstart = tlsend - size; 5053 for (i = 0; i < dtvsize; i++) { 5054 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5055 free_aligned((void *)dtv[i + 2]); 5056 } 5057 } 5058 5059 free_aligned((void *)tlsstart); 5060 free((void*) dtv); 5061 } 5062 5063 #endif 5064 5065 /* 5066 * Allocate TLS block for module with given index. 5067 */ 5068 void * 5069 allocate_module_tls(int index) 5070 { 5071 Obj_Entry* obj; 5072 char* p; 5073 5074 TAILQ_FOREACH(obj, &obj_list, next) { 5075 if (obj->marker) 5076 continue; 5077 if (obj->tlsindex == index) 5078 break; 5079 } 5080 if (!obj) { 5081 _rtld_error("Can't find module with TLS index %d", index); 5082 rtld_die(); 5083 } 5084 5085 p = malloc_aligned(obj->tlssize, obj->tlsalign); 5086 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5087 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5088 5089 return p; 5090 } 5091 5092 bool 5093 allocate_tls_offset(Obj_Entry *obj) 5094 { 5095 size_t off; 5096 5097 if (obj->tls_done) 5098 return true; 5099 5100 if (obj->tlssize == 0) { 5101 obj->tls_done = true; 5102 return true; 5103 } 5104 5105 if (tls_last_offset == 0) 5106 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5107 else 5108 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5109 obj->tlssize, obj->tlsalign); 5110 5111 /* 5112 * If we have already fixed the size of the static TLS block, we 5113 * must stay within that size. When allocating the static TLS, we 5114 * leave a small amount of space spare to be used for dynamically 5115 * loading modules which use static TLS. 5116 */ 5117 if (tls_static_space != 0) { 5118 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5119 return false; 5120 } else if (obj->tlsalign > tls_static_max_align) { 5121 tls_static_max_align = obj->tlsalign; 5122 } 5123 5124 tls_last_offset = obj->tlsoffset = off; 5125 tls_last_size = obj->tlssize; 5126 obj->tls_done = true; 5127 5128 return true; 5129 } 5130 5131 void 5132 free_tls_offset(Obj_Entry *obj) 5133 { 5134 5135 /* 5136 * If we were the last thing to allocate out of the static TLS 5137 * block, we give our space back to the 'allocator'. This is a 5138 * simplistic workaround to allow libGL.so.1 to be loaded and 5139 * unloaded multiple times. 5140 */ 5141 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5142 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5143 tls_last_offset -= obj->tlssize; 5144 tls_last_size = 0; 5145 } 5146 } 5147 5148 void * 5149 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5150 { 5151 void *ret; 5152 RtldLockState lockstate; 5153 5154 wlock_acquire(rtld_bind_lock, &lockstate); 5155 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5156 tcbsize, tcbalign); 5157 lock_release(rtld_bind_lock, &lockstate); 5158 return (ret); 5159 } 5160 5161 void 5162 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5163 { 5164 RtldLockState lockstate; 5165 5166 wlock_acquire(rtld_bind_lock, &lockstate); 5167 free_tls(tcb, tcbsize, tcbalign); 5168 lock_release(rtld_bind_lock, &lockstate); 5169 } 5170 5171 static void 5172 object_add_name(Obj_Entry *obj, const char *name) 5173 { 5174 Name_Entry *entry; 5175 size_t len; 5176 5177 len = strlen(name); 5178 entry = malloc(sizeof(Name_Entry) + len); 5179 5180 if (entry != NULL) { 5181 strcpy(entry->name, name); 5182 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5183 } 5184 } 5185 5186 static int 5187 object_match_name(const Obj_Entry *obj, const char *name) 5188 { 5189 Name_Entry *entry; 5190 5191 STAILQ_FOREACH(entry, &obj->names, link) { 5192 if (strcmp(name, entry->name) == 0) 5193 return (1); 5194 } 5195 return (0); 5196 } 5197 5198 static Obj_Entry * 5199 locate_dependency(const Obj_Entry *obj, const char *name) 5200 { 5201 const Objlist_Entry *entry; 5202 const Needed_Entry *needed; 5203 5204 STAILQ_FOREACH(entry, &list_main, link) { 5205 if (object_match_name(entry->obj, name)) 5206 return entry->obj; 5207 } 5208 5209 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5210 if (strcmp(obj->strtab + needed->name, name) == 0 || 5211 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5212 /* 5213 * If there is DT_NEEDED for the name we are looking for, 5214 * we are all set. Note that object might not be found if 5215 * dependency was not loaded yet, so the function can 5216 * return NULL here. This is expected and handled 5217 * properly by the caller. 5218 */ 5219 return (needed->obj); 5220 } 5221 } 5222 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5223 obj->path, name); 5224 rtld_die(); 5225 } 5226 5227 static int 5228 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5229 const Elf_Vernaux *vna) 5230 { 5231 const Elf_Verdef *vd; 5232 const char *vername; 5233 5234 vername = refobj->strtab + vna->vna_name; 5235 vd = depobj->verdef; 5236 if (vd == NULL) { 5237 _rtld_error("%s: version %s required by %s not defined", 5238 depobj->path, vername, refobj->path); 5239 return (-1); 5240 } 5241 for (;;) { 5242 if (vd->vd_version != VER_DEF_CURRENT) { 5243 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5244 depobj->path, vd->vd_version); 5245 return (-1); 5246 } 5247 if (vna->vna_hash == vd->vd_hash) { 5248 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5249 ((const char *)vd + vd->vd_aux); 5250 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5251 return (0); 5252 } 5253 if (vd->vd_next == 0) 5254 break; 5255 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5256 } 5257 if (vna->vna_flags & VER_FLG_WEAK) 5258 return (0); 5259 _rtld_error("%s: version %s required by %s not found", 5260 depobj->path, vername, refobj->path); 5261 return (-1); 5262 } 5263 5264 static int 5265 rtld_verify_object_versions(Obj_Entry *obj) 5266 { 5267 const Elf_Verneed *vn; 5268 const Elf_Verdef *vd; 5269 const Elf_Verdaux *vda; 5270 const Elf_Vernaux *vna; 5271 const Obj_Entry *depobj; 5272 int maxvernum, vernum; 5273 5274 if (obj->ver_checked) 5275 return (0); 5276 obj->ver_checked = true; 5277 5278 maxvernum = 0; 5279 /* 5280 * Walk over defined and required version records and figure out 5281 * max index used by any of them. Do very basic sanity checking 5282 * while there. 5283 */ 5284 vn = obj->verneed; 5285 while (vn != NULL) { 5286 if (vn->vn_version != VER_NEED_CURRENT) { 5287 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5288 obj->path, vn->vn_version); 5289 return (-1); 5290 } 5291 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5292 for (;;) { 5293 vernum = VER_NEED_IDX(vna->vna_other); 5294 if (vernum > maxvernum) 5295 maxvernum = vernum; 5296 if (vna->vna_next == 0) 5297 break; 5298 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5299 } 5300 if (vn->vn_next == 0) 5301 break; 5302 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5303 } 5304 5305 vd = obj->verdef; 5306 while (vd != NULL) { 5307 if (vd->vd_version != VER_DEF_CURRENT) { 5308 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5309 obj->path, vd->vd_version); 5310 return (-1); 5311 } 5312 vernum = VER_DEF_IDX(vd->vd_ndx); 5313 if (vernum > maxvernum) 5314 maxvernum = vernum; 5315 if (vd->vd_next == 0) 5316 break; 5317 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5318 } 5319 5320 if (maxvernum == 0) 5321 return (0); 5322 5323 /* 5324 * Store version information in array indexable by version index. 5325 * Verify that object version requirements are satisfied along the 5326 * way. 5327 */ 5328 obj->vernum = maxvernum + 1; 5329 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5330 5331 vd = obj->verdef; 5332 while (vd != NULL) { 5333 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5334 vernum = VER_DEF_IDX(vd->vd_ndx); 5335 assert(vernum <= maxvernum); 5336 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5337 obj->vertab[vernum].hash = vd->vd_hash; 5338 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5339 obj->vertab[vernum].file = NULL; 5340 obj->vertab[vernum].flags = 0; 5341 } 5342 if (vd->vd_next == 0) 5343 break; 5344 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5345 } 5346 5347 vn = obj->verneed; 5348 while (vn != NULL) { 5349 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5350 if (depobj == NULL) 5351 return (-1); 5352 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5353 for (;;) { 5354 if (check_object_provided_version(obj, depobj, vna)) 5355 return (-1); 5356 vernum = VER_NEED_IDX(vna->vna_other); 5357 assert(vernum <= maxvernum); 5358 obj->vertab[vernum].hash = vna->vna_hash; 5359 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5360 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5361 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5362 VER_INFO_HIDDEN : 0; 5363 if (vna->vna_next == 0) 5364 break; 5365 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5366 } 5367 if (vn->vn_next == 0) 5368 break; 5369 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5370 } 5371 return 0; 5372 } 5373 5374 static int 5375 rtld_verify_versions(const Objlist *objlist) 5376 { 5377 Objlist_Entry *entry; 5378 int rc; 5379 5380 rc = 0; 5381 STAILQ_FOREACH(entry, objlist, link) { 5382 /* 5383 * Skip dummy objects or objects that have their version requirements 5384 * already checked. 5385 */ 5386 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5387 continue; 5388 if (rtld_verify_object_versions(entry->obj) == -1) { 5389 rc = -1; 5390 if (ld_tracing == NULL) 5391 break; 5392 } 5393 } 5394 if (rc == 0 || ld_tracing != NULL) 5395 rc = rtld_verify_object_versions(&obj_rtld); 5396 return rc; 5397 } 5398 5399 const Ver_Entry * 5400 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5401 { 5402 Elf_Versym vernum; 5403 5404 if (obj->vertab) { 5405 vernum = VER_NDX(obj->versyms[symnum]); 5406 if (vernum >= obj->vernum) { 5407 _rtld_error("%s: symbol %s has wrong verneed value %d", 5408 obj->path, obj->strtab + symnum, vernum); 5409 } else if (obj->vertab[vernum].hash != 0) { 5410 return &obj->vertab[vernum]; 5411 } 5412 } 5413 return NULL; 5414 } 5415 5416 int 5417 _rtld_get_stack_prot(void) 5418 { 5419 5420 return (stack_prot); 5421 } 5422 5423 int 5424 _rtld_is_dlopened(void *arg) 5425 { 5426 Obj_Entry *obj; 5427 RtldLockState lockstate; 5428 int res; 5429 5430 rlock_acquire(rtld_bind_lock, &lockstate); 5431 obj = dlcheck(arg); 5432 if (obj == NULL) 5433 obj = obj_from_addr(arg); 5434 if (obj == NULL) { 5435 _rtld_error("No shared object contains address"); 5436 lock_release(rtld_bind_lock, &lockstate); 5437 return (-1); 5438 } 5439 res = obj->dlopened ? 1 : 0; 5440 lock_release(rtld_bind_lock, &lockstate); 5441 return (res); 5442 } 5443 5444 static int 5445 obj_remap_relro(Obj_Entry *obj, int prot) 5446 { 5447 5448 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5449 prot) == -1) { 5450 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5451 obj->path, prot, rtld_strerror(errno)); 5452 return (-1); 5453 } 5454 return (0); 5455 } 5456 5457 static int 5458 obj_disable_relro(Obj_Entry *obj) 5459 { 5460 5461 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5462 } 5463 5464 static int 5465 obj_enforce_relro(Obj_Entry *obj) 5466 { 5467 5468 return (obj_remap_relro(obj, PROT_READ)); 5469 } 5470 5471 static void 5472 map_stacks_exec(RtldLockState *lockstate) 5473 { 5474 void (*thr_map_stacks_exec)(void); 5475 5476 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5477 return; 5478 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5479 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5480 if (thr_map_stacks_exec != NULL) { 5481 stack_prot |= PROT_EXEC; 5482 thr_map_stacks_exec(); 5483 } 5484 } 5485 5486 static void 5487 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5488 { 5489 Objlist_Entry *elm; 5490 Obj_Entry *obj; 5491 void (*distrib)(size_t, void *, size_t, size_t); 5492 5493 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5494 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5495 if (distrib == NULL) 5496 return; 5497 STAILQ_FOREACH(elm, list, link) { 5498 obj = elm->obj; 5499 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5500 continue; 5501 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5502 obj->tlssize); 5503 obj->static_tls_copied = true; 5504 } 5505 } 5506 5507 void 5508 symlook_init(SymLook *dst, const char *name) 5509 { 5510 5511 bzero(dst, sizeof(*dst)); 5512 dst->name = name; 5513 dst->hash = elf_hash(name); 5514 dst->hash_gnu = gnu_hash(name); 5515 } 5516 5517 static void 5518 symlook_init_from_req(SymLook *dst, const SymLook *src) 5519 { 5520 5521 dst->name = src->name; 5522 dst->hash = src->hash; 5523 dst->hash_gnu = src->hash_gnu; 5524 dst->ventry = src->ventry; 5525 dst->flags = src->flags; 5526 dst->defobj_out = NULL; 5527 dst->sym_out = NULL; 5528 dst->lockstate = src->lockstate; 5529 } 5530 5531 static int 5532 open_binary_fd(const char *argv0, bool search_in_path, 5533 const char **binpath_res) 5534 { 5535 char *binpath, *pathenv, *pe, *res1; 5536 const char *res; 5537 int fd; 5538 5539 binpath = NULL; 5540 res = NULL; 5541 if (search_in_path && strchr(argv0, '/') == NULL) { 5542 binpath = xmalloc(PATH_MAX); 5543 pathenv = getenv("PATH"); 5544 if (pathenv == NULL) { 5545 _rtld_error("-p and no PATH environment variable"); 5546 rtld_die(); 5547 } 5548 pathenv = strdup(pathenv); 5549 if (pathenv == NULL) { 5550 _rtld_error("Cannot allocate memory"); 5551 rtld_die(); 5552 } 5553 fd = -1; 5554 errno = ENOENT; 5555 while ((pe = strsep(&pathenv, ":")) != NULL) { 5556 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5557 continue; 5558 if (binpath[0] != '\0' && 5559 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5560 continue; 5561 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5562 continue; 5563 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5564 if (fd != -1 || errno != ENOENT) { 5565 res = binpath; 5566 break; 5567 } 5568 } 5569 free(pathenv); 5570 } else { 5571 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5572 res = argv0; 5573 } 5574 5575 if (fd == -1) { 5576 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5577 rtld_die(); 5578 } 5579 if (res != NULL && res[0] != '/') { 5580 res1 = xmalloc(PATH_MAX); 5581 if (realpath(res, res1) != NULL) { 5582 if (res != argv0) 5583 free(__DECONST(char *, res)); 5584 res = res1; 5585 } else { 5586 free(res1); 5587 } 5588 } 5589 *binpath_res = res; 5590 return (fd); 5591 } 5592 5593 /* 5594 * Parse a set of command-line arguments. 5595 */ 5596 static int 5597 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5598 { 5599 const char *arg; 5600 int fd, i, j, arglen; 5601 char opt; 5602 5603 dbg("Parsing command-line arguments"); 5604 *use_pathp = false; 5605 *fdp = -1; 5606 5607 for (i = 1; i < argc; i++ ) { 5608 arg = argv[i]; 5609 dbg("argv[%d]: '%s'", i, arg); 5610 5611 /* 5612 * rtld arguments end with an explicit "--" or with the first 5613 * non-prefixed argument. 5614 */ 5615 if (strcmp(arg, "--") == 0) { 5616 i++; 5617 break; 5618 } 5619 if (arg[0] != '-') 5620 break; 5621 5622 /* 5623 * All other arguments are single-character options that can 5624 * be combined, so we need to search through `arg` for them. 5625 */ 5626 arglen = strlen(arg); 5627 for (j = 1; j < arglen; j++) { 5628 opt = arg[j]; 5629 if (opt == 'h') { 5630 print_usage(argv[0]); 5631 _exit(0); 5632 } else if (opt == 'f') { 5633 /* 5634 * -f XX can be used to specify a 5635 * descriptor for the binary named at 5636 * the command line (i.e., the later 5637 * argument will specify the process 5638 * name but the descriptor is what 5639 * will actually be executed). 5640 * 5641 * -f must be the last option in, e.g., -abcf. 5642 */ 5643 if (j != arglen - 1) { 5644 _rtld_error("Invalid options: %s", arg); 5645 rtld_die(); 5646 } 5647 i++; 5648 fd = parse_integer(argv[i]); 5649 if (fd == -1) { 5650 _rtld_error( 5651 "Invalid file descriptor: '%s'", 5652 argv[i]); 5653 rtld_die(); 5654 } 5655 *fdp = fd; 5656 break; 5657 } else if (opt == 'p') { 5658 *use_pathp = true; 5659 } else { 5660 _rtld_error("Invalid argument: '%s'", arg); 5661 print_usage(argv[0]); 5662 rtld_die(); 5663 } 5664 } 5665 } 5666 5667 return (i); 5668 } 5669 5670 /* 5671 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5672 */ 5673 static int 5674 parse_integer(const char *str) 5675 { 5676 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5677 const char *orig; 5678 int n; 5679 char c; 5680 5681 orig = str; 5682 n = 0; 5683 for (c = *str; c != '\0'; c = *++str) { 5684 if (c < '0' || c > '9') 5685 return (-1); 5686 5687 n *= RADIX; 5688 n += c - '0'; 5689 } 5690 5691 /* Make sure we actually parsed something. */ 5692 if (str == orig) 5693 return (-1); 5694 return (n); 5695 } 5696 5697 static void 5698 print_usage(const char *argv0) 5699 { 5700 5701 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5702 "\n" 5703 "Options:\n" 5704 " -h Display this help message\n" 5705 " -p Search in PATH for named binary\n" 5706 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5707 " -- End of RTLD options\n" 5708 " <binary> Name of process to execute\n" 5709 " <args> Arguments to the executed process\n", argv0); 5710 } 5711 5712 /* 5713 * Overrides for libc_pic-provided functions. 5714 */ 5715 5716 int 5717 __getosreldate(void) 5718 { 5719 size_t len; 5720 int oid[2]; 5721 int error, osrel; 5722 5723 if (osreldate != 0) 5724 return (osreldate); 5725 5726 oid[0] = CTL_KERN; 5727 oid[1] = KERN_OSRELDATE; 5728 osrel = 0; 5729 len = sizeof(osrel); 5730 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5731 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5732 osreldate = osrel; 5733 return (osreldate); 5734 } 5735 const char * 5736 rtld_strerror(int errnum) 5737 { 5738 5739 if (errnum < 0 || errnum >= sys_nerr) 5740 return ("Unknown error"); 5741 return (sys_errlist[errnum]); 5742 } 5743 5744 /* malloc */ 5745 void * 5746 malloc(size_t nbytes) 5747 { 5748 5749 return (__crt_malloc(nbytes)); 5750 } 5751 5752 void * 5753 calloc(size_t num, size_t size) 5754 { 5755 5756 return (__crt_calloc(num, size)); 5757 } 5758 5759 void 5760 free(void *cp) 5761 { 5762 5763 __crt_free(cp); 5764 } 5765 5766 void * 5767 realloc(void *cp, size_t nbytes) 5768 { 5769 5770 return (__crt_realloc(cp, nbytes)); 5771 } 5772