1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path, 138 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 140 const char **argv0); 141 static int parse_integer(const char *); 142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 143 static void print_usage(const char *argv0); 144 static void release_object(Obj_Entry *); 145 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 148 int flags, RtldLockState *lockstate); 149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 150 RtldLockState *); 151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 152 static int rtld_dirname(const char *, char *); 153 static int rtld_dirname_abs(const char *, char *); 154 static void *rtld_dlopen(const char *name, int fd, int mode); 155 static void rtld_exit(void); 156 static void rtld_nop_exit(void); 157 static char *search_library_path(const char *, const char *, const char *, 158 int *); 159 static char *search_library_pathfds(const char *, const char *, int *); 160 static const void **get_program_var_addr(const char *, RtldLockState *); 161 static void set_program_var(const char *, const void *); 162 static int symlook_default(SymLook *, const Obj_Entry *refobj); 163 static int symlook_global(SymLook *, DoneList *); 164 static void symlook_init_from_req(SymLook *, const SymLook *); 165 static int symlook_list(SymLook *, const Objlist *, DoneList *); 166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 169 static void trace_loaded_objects(Obj_Entry *); 170 static void unlink_object(Obj_Entry *); 171 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 172 static void unref_dag(Obj_Entry *); 173 static void ref_dag(Obj_Entry *); 174 static char *origin_subst_one(Obj_Entry *, char *, const char *, 175 const char *, bool); 176 static char *origin_subst(Obj_Entry *, const char *); 177 static bool obj_resolve_origin(Obj_Entry *obj); 178 static void preinit_main(void); 179 static int rtld_verify_versions(const Objlist *); 180 static int rtld_verify_object_versions(Obj_Entry *); 181 static void object_add_name(Obj_Entry *, const char *); 182 static int object_match_name(const Obj_Entry *, const char *); 183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 185 struct dl_phdr_info *phdr_info); 186 static uint32_t gnu_hash(const char *); 187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 188 const unsigned long); 189 190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 191 void _r_debug_postinit(struct link_map *) __noinline __exported; 192 193 int __sys_openat(int, const char *, int, ...); 194 195 /* 196 * Data declarations. 197 */ 198 static char *error_message; /* Message for dlerror(), or NULL */ 199 struct r_debug r_debug __exported; /* for GDB; */ 200 static bool libmap_disable; /* Disable libmap */ 201 static bool ld_loadfltr; /* Immediate filters processing */ 202 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 203 static bool trust; /* False for setuid and setgid programs */ 204 static bool dangerous_ld_env; /* True if environment variables have been 205 used to affect the libraries loaded */ 206 bool ld_bind_not; /* Disable PLT update */ 207 static char *ld_bind_now; /* Environment variable for immediate binding */ 208 static char *ld_debug; /* Environment variable for debugging */ 209 static char *ld_library_path; /* Environment variable for search path */ 210 static char *ld_library_dirs; /* Environment variable for library descriptors */ 211 static char *ld_preload; /* Environment variable for libraries to 212 load first */ 213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 214 static const char *ld_tracing; /* Called from ldd to print libs */ 215 static char *ld_utrace; /* Use utrace() to log events. */ 216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 217 static Obj_Entry *obj_main; /* The main program shared object */ 218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 219 static unsigned int obj_count; /* Number of objects in obj_list */ 220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 221 222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 223 STAILQ_HEAD_INITIALIZER(list_global); 224 static Objlist list_main = /* Objects loaded at program startup */ 225 STAILQ_HEAD_INITIALIZER(list_main); 226 static Objlist list_fini = /* Objects needing fini() calls */ 227 STAILQ_HEAD_INITIALIZER(list_fini); 228 229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 230 231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 232 233 extern Elf_Dyn _DYNAMIC; 234 #pragma weak _DYNAMIC 235 236 int dlclose(void *) __exported; 237 char *dlerror(void) __exported; 238 void *dlopen(const char *, int) __exported; 239 void *fdlopen(int, int) __exported; 240 void *dlsym(void *, const char *) __exported; 241 dlfunc_t dlfunc(void *, const char *) __exported; 242 void *dlvsym(void *, const char *, const char *) __exported; 243 int dladdr(const void *, Dl_info *) __exported; 244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 246 int dlinfo(void *, int , void *) __exported; 247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 249 int _rtld_get_stack_prot(void) __exported; 250 int _rtld_is_dlopened(void *) __exported; 251 void _rtld_error(const char *, ...) __exported; 252 253 /* Only here to fix -Wmissing-prototypes warnings */ 254 int __getosreldate(void); 255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 257 258 259 int npagesizes; 260 static int osreldate; 261 size_t *pagesizes; 262 263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 264 static int max_stack_flags; 265 266 /* 267 * Global declarations normally provided by crt1. The dynamic linker is 268 * not built with crt1, so we have to provide them ourselves. 269 */ 270 char *__progname; 271 char **environ; 272 273 /* 274 * Used to pass argc, argv to init functions. 275 */ 276 int main_argc; 277 char **main_argv; 278 279 /* 280 * Globals to control TLS allocation. 281 */ 282 size_t tls_last_offset; /* Static TLS offset of last module */ 283 size_t tls_last_size; /* Static TLS size of last module */ 284 size_t tls_static_space; /* Static TLS space allocated */ 285 static size_t tls_static_max_align; 286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 287 int tls_max_index = 1; /* Largest module index allocated */ 288 289 static bool ld_library_path_rpath = false; 290 bool ld_fast_sigblock = false; 291 292 /* 293 * Globals for path names, and such 294 */ 295 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 297 const char *ld_path_rtld = _PATH_RTLD; 298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 299 const char *ld_env_prefix = LD_; 300 301 static void (*rtld_exit_ptr)(void); 302 303 /* 304 * Fill in a DoneList with an allocation large enough to hold all of 305 * the currently-loaded objects. Keep this as a macro since it calls 306 * alloca and we want that to occur within the scope of the caller. 307 */ 308 #define donelist_init(dlp) \ 309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 310 assert((dlp)->objs != NULL), \ 311 (dlp)->num_alloc = obj_count, \ 312 (dlp)->num_used = 0) 313 314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 315 if (ld_utrace != NULL) \ 316 ld_utrace_log(e, h, mb, ms, r, n); \ 317 } while (0) 318 319 static void 320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 321 int refcnt, const char *name) 322 { 323 struct utrace_rtld ut; 324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 325 326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 327 ut.event = event; 328 ut.handle = handle; 329 ut.mapbase = mapbase; 330 ut.mapsize = mapsize; 331 ut.refcnt = refcnt; 332 bzero(ut.name, sizeof(ut.name)); 333 if (name) 334 strlcpy(ut.name, name, sizeof(ut.name)); 335 utrace(&ut, sizeof(ut)); 336 } 337 338 #ifdef RTLD_VARIANT_ENV_NAMES 339 /* 340 * construct the env variable based on the type of binary that's 341 * running. 342 */ 343 static inline const char * 344 _LD(const char *var) 345 { 346 static char buffer[128]; 347 348 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 349 strlcat(buffer, var, sizeof(buffer)); 350 return (buffer); 351 } 352 #else 353 #define _LD(x) LD_ x 354 #endif 355 356 /* 357 * Main entry point for dynamic linking. The first argument is the 358 * stack pointer. The stack is expected to be laid out as described 359 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 360 * Specifically, the stack pointer points to a word containing 361 * ARGC. Following that in the stack is a null-terminated sequence 362 * of pointers to argument strings. Then comes a null-terminated 363 * sequence of pointers to environment strings. Finally, there is a 364 * sequence of "auxiliary vector" entries. 365 * 366 * The second argument points to a place to store the dynamic linker's 367 * exit procedure pointer and the third to a place to store the main 368 * program's object. 369 * 370 * The return value is the main program's entry point. 371 */ 372 func_ptr_type 373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 374 { 375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 376 Objlist_Entry *entry; 377 Obj_Entry *last_interposer, *obj, *preload_tail; 378 const Elf_Phdr *phdr; 379 Objlist initlist; 380 RtldLockState lockstate; 381 struct stat st; 382 Elf_Addr *argcp; 383 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 384 const char *argv0, *binpath; 385 caddr_t imgentry; 386 char buf[MAXPATHLEN]; 387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 388 size_t sz; 389 #ifdef __powerpc__ 390 int old_auxv_format = 1; 391 #endif 392 bool dir_enable, direct_exec, explicit_fd, search_in_path; 393 394 /* 395 * On entry, the dynamic linker itself has not been relocated yet. 396 * Be very careful not to reference any global data until after 397 * init_rtld has returned. It is OK to reference file-scope statics 398 * and string constants, and to call static and global functions. 399 */ 400 401 /* Find the auxiliary vector on the stack. */ 402 argcp = sp; 403 argc = *sp++; 404 argv = (char **) sp; 405 sp += argc + 1; /* Skip over arguments and NULL terminator */ 406 env = (char **) sp; 407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 408 ; 409 aux = (Elf_Auxinfo *) sp; 410 411 /* Digest the auxiliary vector. */ 412 for (i = 0; i < AT_COUNT; i++) 413 aux_info[i] = NULL; 414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 415 if (auxp->a_type < AT_COUNT) 416 aux_info[auxp->a_type] = auxp; 417 #ifdef __powerpc__ 418 if (auxp->a_type == 23) /* AT_STACKPROT */ 419 old_auxv_format = 0; 420 #endif 421 } 422 423 #ifdef __powerpc__ 424 if (old_auxv_format) { 425 /* Remap from old-style auxv numbers. */ 426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 428 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 431 aux_info[13] = NULL; /* AT_GID */ 432 433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 435 aux_info[16] = aux_info[14]; /* AT_CANARY */ 436 aux_info[14] = NULL; /* AT_EGID */ 437 } 438 #endif 439 440 /* Initialize and relocate ourselves. */ 441 assert(aux_info[AT_BASE] != NULL); 442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 443 444 __progname = obj_rtld.path; 445 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 446 environ = env; 447 main_argc = argc; 448 main_argv = argv; 449 450 if (aux_info[AT_BSDFLAGS] != NULL && 451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 452 ld_fast_sigblock = true; 453 454 trust = !issetugid(); 455 direct_exec = false; 456 457 md_abi_variant_hook(aux_info); 458 459 fd = -1; 460 if (aux_info[AT_EXECFD] != NULL) { 461 fd = aux_info[AT_EXECFD]->a_un.a_val; 462 } else { 463 assert(aux_info[AT_PHDR] != NULL); 464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 465 if (phdr == obj_rtld.phdr) { 466 if (!trust) { 467 _rtld_error("Tainted process refusing to run binary %s", 468 argv0); 469 rtld_die(); 470 } 471 direct_exec = true; 472 473 dbg("opening main program in direct exec mode"); 474 if (argc >= 2) { 475 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 476 explicit_fd = (fd != -1); 477 binpath = NULL; 478 if (!explicit_fd) 479 fd = open_binary_fd(argv0, search_in_path, &binpath); 480 if (fstat(fd, &st) == -1) { 481 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 482 explicit_fd ? "user-provided descriptor" : argv0, 483 rtld_strerror(errno)); 484 rtld_die(); 485 } 486 487 /* 488 * Rough emulation of the permission checks done by 489 * execve(2), only Unix DACs are checked, ACLs are 490 * ignored. Preserve the semantic of disabling owner 491 * to execute if owner x bit is cleared, even if 492 * others x bit is enabled. 493 * mmap(2) does not allow to mmap with PROT_EXEC if 494 * binary' file comes from noexec mount. We cannot 495 * set a text reference on the binary. 496 */ 497 dir_enable = false; 498 if (st.st_uid == geteuid()) { 499 if ((st.st_mode & S_IXUSR) != 0) 500 dir_enable = true; 501 } else if (st.st_gid == getegid()) { 502 if ((st.st_mode & S_IXGRP) != 0) 503 dir_enable = true; 504 } else if ((st.st_mode & S_IXOTH) != 0) { 505 dir_enable = true; 506 } 507 if (!dir_enable) { 508 _rtld_error("No execute permission for binary %s", 509 argv0); 510 rtld_die(); 511 } 512 513 /* 514 * For direct exec mode, argv[0] is the interpreter 515 * name, we must remove it and shift arguments left 516 * before invoking binary main. Since stack layout 517 * places environment pointers and aux vectors right 518 * after the terminating NULL, we must shift 519 * environment and aux as well. 520 */ 521 main_argc = argc - rtld_argc; 522 for (i = 0; i <= main_argc; i++) 523 argv[i] = argv[i + rtld_argc]; 524 *argcp -= rtld_argc; 525 environ = env = envp = argv + main_argc + 1; 526 dbg("move env from %p to %p", envp + rtld_argc, envp); 527 do { 528 *envp = *(envp + rtld_argc); 529 } while (*envp++ != NULL); 530 aux = auxp = (Elf_Auxinfo *)envp; 531 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 532 dbg("move aux from %p to %p", auxpf, aux); 533 /* XXXKIB insert place for AT_EXECPATH if not present */ 534 for (;; auxp++, auxpf++) { 535 *auxp = *auxpf; 536 if (auxp->a_type == AT_NULL) 537 break; 538 } 539 /* Since the auxiliary vector has moved, redigest it. */ 540 for (i = 0; i < AT_COUNT; i++) 541 aux_info[i] = NULL; 542 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 543 if (auxp->a_type < AT_COUNT) 544 aux_info[auxp->a_type] = auxp; 545 } 546 547 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 548 if (binpath == NULL) { 549 aux_info[AT_EXECPATH] = NULL; 550 } else { 551 if (aux_info[AT_EXECPATH] == NULL) { 552 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 553 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 554 } 555 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 556 binpath); 557 } 558 } else { 559 _rtld_error("No binary"); 560 rtld_die(); 561 } 562 } 563 } 564 565 ld_bind_now = getenv(_LD("BIND_NOW")); 566 567 /* 568 * If the process is tainted, then we un-set the dangerous environment 569 * variables. The process will be marked as tainted until setuid(2) 570 * is called. If any child process calls setuid(2) we do not want any 571 * future processes to honor the potentially un-safe variables. 572 */ 573 if (!trust) { 574 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 575 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 576 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 577 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 578 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 579 _rtld_error("environment corrupt; aborting"); 580 rtld_die(); 581 } 582 } 583 ld_debug = getenv(_LD("DEBUG")); 584 if (ld_bind_now == NULL) 585 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 586 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 587 libmap_override = getenv(_LD("LIBMAP")); 588 ld_library_path = getenv(_LD("LIBRARY_PATH")); 589 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 590 ld_preload = getenv(_LD("PRELOAD")); 591 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 592 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 593 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 594 if (library_path_rpath != NULL) { 595 if (library_path_rpath[0] == 'y' || 596 library_path_rpath[0] == 'Y' || 597 library_path_rpath[0] == '1') 598 ld_library_path_rpath = true; 599 else 600 ld_library_path_rpath = false; 601 } 602 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 603 (ld_library_path != NULL) || (ld_preload != NULL) || 604 (ld_elf_hints_path != NULL) || ld_loadfltr; 605 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 606 ld_utrace = getenv(_LD("UTRACE")); 607 608 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 609 ld_elf_hints_path = ld_elf_hints_default; 610 611 if (ld_debug != NULL && *ld_debug != '\0') 612 debug = 1; 613 dbg("%s is initialized, base address = %p", __progname, 614 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 615 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 616 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 617 618 dbg("initializing thread locks"); 619 lockdflt_init(); 620 621 /* 622 * Load the main program, or process its program header if it is 623 * already loaded. 624 */ 625 if (fd != -1) { /* Load the main program. */ 626 dbg("loading main program"); 627 obj_main = map_object(fd, argv0, NULL); 628 close(fd); 629 if (obj_main == NULL) 630 rtld_die(); 631 max_stack_flags = obj_main->stack_flags; 632 } else { /* Main program already loaded. */ 633 dbg("processing main program's program header"); 634 assert(aux_info[AT_PHDR] != NULL); 635 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 636 assert(aux_info[AT_PHNUM] != NULL); 637 phnum = aux_info[AT_PHNUM]->a_un.a_val; 638 assert(aux_info[AT_PHENT] != NULL); 639 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 640 assert(aux_info[AT_ENTRY] != NULL); 641 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 642 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 643 rtld_die(); 644 } 645 646 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 647 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 648 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 649 if (kexecpath[0] == '/') 650 obj_main->path = kexecpath; 651 else if (getcwd(buf, sizeof(buf)) == NULL || 652 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 653 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 654 obj_main->path = xstrdup(argv0); 655 else 656 obj_main->path = xstrdup(buf); 657 } else { 658 dbg("No AT_EXECPATH or direct exec"); 659 obj_main->path = xstrdup(argv0); 660 } 661 dbg("obj_main path %s", obj_main->path); 662 obj_main->mainprog = true; 663 664 if (aux_info[AT_STACKPROT] != NULL && 665 aux_info[AT_STACKPROT]->a_un.a_val != 0) 666 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 667 668 #ifndef COMPAT_32BIT 669 /* 670 * Get the actual dynamic linker pathname from the executable if 671 * possible. (It should always be possible.) That ensures that 672 * gdb will find the right dynamic linker even if a non-standard 673 * one is being used. 674 */ 675 if (obj_main->interp != NULL && 676 strcmp(obj_main->interp, obj_rtld.path) != 0) { 677 free(obj_rtld.path); 678 obj_rtld.path = xstrdup(obj_main->interp); 679 __progname = obj_rtld.path; 680 } 681 #endif 682 683 if (!digest_dynamic(obj_main, 0)) 684 rtld_die(); 685 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 686 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 687 obj_main->dynsymcount); 688 689 linkmap_add(obj_main); 690 linkmap_add(&obj_rtld); 691 692 /* Link the main program into the list of objects. */ 693 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 694 obj_count++; 695 obj_loads++; 696 697 /* Initialize a fake symbol for resolving undefined weak references. */ 698 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 699 sym_zero.st_shndx = SHN_UNDEF; 700 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 701 702 if (!libmap_disable) 703 libmap_disable = (bool)lm_init(libmap_override); 704 705 dbg("loading LD_PRELOAD libraries"); 706 if (load_preload_objects() == -1) 707 rtld_die(); 708 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 709 710 dbg("loading needed objects"); 711 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 712 0) == -1) 713 rtld_die(); 714 715 /* Make a list of all objects loaded at startup. */ 716 last_interposer = obj_main; 717 TAILQ_FOREACH(obj, &obj_list, next) { 718 if (obj->marker) 719 continue; 720 if (obj->z_interpose && obj != obj_main) { 721 objlist_put_after(&list_main, last_interposer, obj); 722 last_interposer = obj; 723 } else { 724 objlist_push_tail(&list_main, obj); 725 } 726 obj->refcount++; 727 } 728 729 dbg("checking for required versions"); 730 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 731 rtld_die(); 732 733 if (ld_tracing) { /* We're done */ 734 trace_loaded_objects(obj_main); 735 exit(0); 736 } 737 738 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 739 dump_relocations(obj_main); 740 exit (0); 741 } 742 743 /* 744 * Processing tls relocations requires having the tls offsets 745 * initialized. Prepare offsets before starting initial 746 * relocation processing. 747 */ 748 dbg("initializing initial thread local storage offsets"); 749 STAILQ_FOREACH(entry, &list_main, link) { 750 /* 751 * Allocate all the initial objects out of the static TLS 752 * block even if they didn't ask for it. 753 */ 754 allocate_tls_offset(entry->obj); 755 } 756 757 if (relocate_objects(obj_main, 758 ld_bind_now != NULL && *ld_bind_now != '\0', 759 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 760 rtld_die(); 761 762 dbg("doing copy relocations"); 763 if (do_copy_relocations(obj_main) == -1) 764 rtld_die(); 765 766 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 767 dump_relocations(obj_main); 768 exit (0); 769 } 770 771 ifunc_init(aux); 772 773 /* 774 * Setup TLS for main thread. This must be done after the 775 * relocations are processed, since tls initialization section 776 * might be the subject for relocations. 777 */ 778 dbg("initializing initial thread local storage"); 779 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 780 781 dbg("initializing key program variables"); 782 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 783 set_program_var("environ", env); 784 set_program_var("__elf_aux_vector", aux); 785 786 /* Make a list of init functions to call. */ 787 objlist_init(&initlist); 788 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 789 preload_tail, &initlist); 790 791 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 792 793 map_stacks_exec(NULL); 794 795 if (!obj_main->crt_no_init) { 796 /* 797 * Make sure we don't call the main program's init and fini 798 * functions for binaries linked with old crt1 which calls 799 * _init itself. 800 */ 801 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 802 obj_main->preinit_array = obj_main->init_array = 803 obj_main->fini_array = (Elf_Addr)NULL; 804 } 805 806 if (direct_exec) { 807 /* Set osrel for direct-execed binary */ 808 mib[0] = CTL_KERN; 809 mib[1] = KERN_PROC; 810 mib[2] = KERN_PROC_OSREL; 811 mib[3] = getpid(); 812 osrel = obj_main->osrel; 813 sz = sizeof(old_osrel); 814 dbg("setting osrel to %d", osrel); 815 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 816 } 817 818 wlock_acquire(rtld_bind_lock, &lockstate); 819 820 dbg("resolving ifuncs"); 821 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 822 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 823 rtld_die(); 824 825 rtld_exit_ptr = rtld_exit; 826 if (obj_main->crt_no_init) 827 preinit_main(); 828 objlist_call_init(&initlist, &lockstate); 829 _r_debug_postinit(&obj_main->linkmap); 830 objlist_clear(&initlist); 831 dbg("loading filtees"); 832 TAILQ_FOREACH(obj, &obj_list, next) { 833 if (obj->marker) 834 continue; 835 if (ld_loadfltr || obj->z_loadfltr) 836 load_filtees(obj, 0, &lockstate); 837 } 838 839 dbg("enforcing main obj relro"); 840 if (obj_enforce_relro(obj_main) == -1) 841 rtld_die(); 842 843 lock_release(rtld_bind_lock, &lockstate); 844 845 dbg("transferring control to program entry point = %p", obj_main->entry); 846 847 /* Return the exit procedure and the program entry point. */ 848 *exit_proc = rtld_exit_ptr; 849 *objp = obj_main; 850 return (func_ptr_type) obj_main->entry; 851 } 852 853 void * 854 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 855 { 856 void *ptr; 857 Elf_Addr target; 858 859 ptr = (void *)make_function_pointer(def, obj); 860 target = call_ifunc_resolver(ptr); 861 return ((void *)target); 862 } 863 864 /* 865 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 866 * Changes to this function should be applied there as well. 867 */ 868 Elf_Addr 869 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 870 { 871 const Elf_Rel *rel; 872 const Elf_Sym *def; 873 const Obj_Entry *defobj; 874 Elf_Addr *where; 875 Elf_Addr target; 876 RtldLockState lockstate; 877 878 rlock_acquire(rtld_bind_lock, &lockstate); 879 if (sigsetjmp(lockstate.env, 0) != 0) 880 lock_upgrade(rtld_bind_lock, &lockstate); 881 if (obj->pltrel) 882 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 883 else 884 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 885 886 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 887 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 888 NULL, &lockstate); 889 if (def == NULL) 890 rtld_die(); 891 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 892 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 893 else 894 target = (Elf_Addr)(defobj->relocbase + def->st_value); 895 896 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 897 defobj->strtab + def->st_name, basename(obj->path), 898 (void *)target, basename(defobj->path)); 899 900 /* 901 * Write the new contents for the jmpslot. Note that depending on 902 * architecture, the value which we need to return back to the 903 * lazy binding trampoline may or may not be the target 904 * address. The value returned from reloc_jmpslot() is the value 905 * that the trampoline needs. 906 */ 907 target = reloc_jmpslot(where, target, defobj, obj, rel); 908 lock_release(rtld_bind_lock, &lockstate); 909 return target; 910 } 911 912 /* 913 * Error reporting function. Use it like printf. If formats the message 914 * into a buffer, and sets things up so that the next call to dlerror() 915 * will return the message. 916 */ 917 void 918 _rtld_error(const char *fmt, ...) 919 { 920 static char buf[512]; 921 va_list ap; 922 923 va_start(ap, fmt); 924 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 925 error_message = buf; 926 va_end(ap); 927 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 928 } 929 930 /* 931 * Return a dynamically-allocated copy of the current error message, if any. 932 */ 933 static char * 934 errmsg_save(void) 935 { 936 return error_message == NULL ? NULL : xstrdup(error_message); 937 } 938 939 /* 940 * Restore the current error message from a copy which was previously saved 941 * by errmsg_save(). The copy is freed. 942 */ 943 static void 944 errmsg_restore(char *saved_msg) 945 { 946 if (saved_msg == NULL) 947 error_message = NULL; 948 else { 949 _rtld_error("%s", saved_msg); 950 free(saved_msg); 951 } 952 } 953 954 static const char * 955 basename(const char *name) 956 { 957 const char *p = strrchr(name, '/'); 958 return p != NULL ? p + 1 : name; 959 } 960 961 static struct utsname uts; 962 963 static char * 964 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 965 const char *subst, bool may_free) 966 { 967 char *p, *p1, *res, *resp; 968 int subst_len, kw_len, subst_count, old_len, new_len; 969 970 kw_len = strlen(kw); 971 972 /* 973 * First, count the number of the keyword occurrences, to 974 * preallocate the final string. 975 */ 976 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 977 p1 = strstr(p, kw); 978 if (p1 == NULL) 979 break; 980 } 981 982 /* 983 * If the keyword is not found, just return. 984 * 985 * Return non-substituted string if resolution failed. We 986 * cannot do anything more reasonable, the failure mode of the 987 * caller is unresolved library anyway. 988 */ 989 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 990 return (may_free ? real : xstrdup(real)); 991 if (obj != NULL) 992 subst = obj->origin_path; 993 994 /* 995 * There is indeed something to substitute. Calculate the 996 * length of the resulting string, and allocate it. 997 */ 998 subst_len = strlen(subst); 999 old_len = strlen(real); 1000 new_len = old_len + (subst_len - kw_len) * subst_count; 1001 res = xmalloc(new_len + 1); 1002 1003 /* 1004 * Now, execute the substitution loop. 1005 */ 1006 for (p = real, resp = res, *resp = '\0';;) { 1007 p1 = strstr(p, kw); 1008 if (p1 != NULL) { 1009 /* Copy the prefix before keyword. */ 1010 memcpy(resp, p, p1 - p); 1011 resp += p1 - p; 1012 /* Keyword replacement. */ 1013 memcpy(resp, subst, subst_len); 1014 resp += subst_len; 1015 *resp = '\0'; 1016 p = p1 + kw_len; 1017 } else 1018 break; 1019 } 1020 1021 /* Copy to the end of string and finish. */ 1022 strcat(resp, p); 1023 if (may_free) 1024 free(real); 1025 return (res); 1026 } 1027 1028 static char * 1029 origin_subst(Obj_Entry *obj, const char *real) 1030 { 1031 char *res1, *res2, *res3, *res4; 1032 1033 if (obj == NULL || !trust) 1034 return (xstrdup(real)); 1035 if (uts.sysname[0] == '\0') { 1036 if (uname(&uts) != 0) { 1037 _rtld_error("utsname failed: %d", errno); 1038 return (NULL); 1039 } 1040 } 1041 /* __DECONST is safe here since without may_free real is unchanged */ 1042 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1043 false); 1044 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1045 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1046 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1047 return (res4); 1048 } 1049 1050 void 1051 rtld_die(void) 1052 { 1053 const char *msg = dlerror(); 1054 1055 if (msg == NULL) 1056 msg = "Fatal error"; 1057 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1058 rtld_fdputstr(STDERR_FILENO, msg); 1059 rtld_fdputchar(STDERR_FILENO, '\n'); 1060 _exit(1); 1061 } 1062 1063 /* 1064 * Process a shared object's DYNAMIC section, and save the important 1065 * information in its Obj_Entry structure. 1066 */ 1067 static void 1068 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1069 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1070 { 1071 const Elf_Dyn *dynp; 1072 Needed_Entry **needed_tail = &obj->needed; 1073 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1074 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1075 const Elf_Hashelt *hashtab; 1076 const Elf32_Word *hashval; 1077 Elf32_Word bkt, nmaskwords; 1078 int bloom_size32; 1079 int plttype = DT_REL; 1080 1081 *dyn_rpath = NULL; 1082 *dyn_soname = NULL; 1083 *dyn_runpath = NULL; 1084 1085 obj->bind_now = false; 1086 dynp = obj->dynamic; 1087 if (dynp == NULL) 1088 return; 1089 for (; dynp->d_tag != DT_NULL; dynp++) { 1090 switch (dynp->d_tag) { 1091 1092 case DT_REL: 1093 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1094 break; 1095 1096 case DT_RELSZ: 1097 obj->relsize = dynp->d_un.d_val; 1098 break; 1099 1100 case DT_RELENT: 1101 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1102 break; 1103 1104 case DT_JMPREL: 1105 obj->pltrel = (const Elf_Rel *) 1106 (obj->relocbase + dynp->d_un.d_ptr); 1107 break; 1108 1109 case DT_PLTRELSZ: 1110 obj->pltrelsize = dynp->d_un.d_val; 1111 break; 1112 1113 case DT_RELA: 1114 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1115 break; 1116 1117 case DT_RELASZ: 1118 obj->relasize = dynp->d_un.d_val; 1119 break; 1120 1121 case DT_RELAENT: 1122 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1123 break; 1124 1125 case DT_PLTREL: 1126 plttype = dynp->d_un.d_val; 1127 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1128 break; 1129 1130 case DT_SYMTAB: 1131 obj->symtab = (const Elf_Sym *) 1132 (obj->relocbase + dynp->d_un.d_ptr); 1133 break; 1134 1135 case DT_SYMENT: 1136 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1137 break; 1138 1139 case DT_STRTAB: 1140 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1141 break; 1142 1143 case DT_STRSZ: 1144 obj->strsize = dynp->d_un.d_val; 1145 break; 1146 1147 case DT_VERNEED: 1148 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1149 dynp->d_un.d_val); 1150 break; 1151 1152 case DT_VERNEEDNUM: 1153 obj->verneednum = dynp->d_un.d_val; 1154 break; 1155 1156 case DT_VERDEF: 1157 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1158 dynp->d_un.d_val); 1159 break; 1160 1161 case DT_VERDEFNUM: 1162 obj->verdefnum = dynp->d_un.d_val; 1163 break; 1164 1165 case DT_VERSYM: 1166 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1167 dynp->d_un.d_val); 1168 break; 1169 1170 case DT_HASH: 1171 { 1172 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1173 dynp->d_un.d_ptr); 1174 obj->nbuckets = hashtab[0]; 1175 obj->nchains = hashtab[1]; 1176 obj->buckets = hashtab + 2; 1177 obj->chains = obj->buckets + obj->nbuckets; 1178 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1179 obj->buckets != NULL; 1180 } 1181 break; 1182 1183 case DT_GNU_HASH: 1184 { 1185 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1186 dynp->d_un.d_ptr); 1187 obj->nbuckets_gnu = hashtab[0]; 1188 obj->symndx_gnu = hashtab[1]; 1189 nmaskwords = hashtab[2]; 1190 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1191 obj->maskwords_bm_gnu = nmaskwords - 1; 1192 obj->shift2_gnu = hashtab[3]; 1193 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1194 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1195 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1196 obj->symndx_gnu; 1197 /* Number of bitmask words is required to be power of 2 */ 1198 obj->valid_hash_gnu = powerof2(nmaskwords) && 1199 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1200 } 1201 break; 1202 1203 case DT_NEEDED: 1204 if (!obj->rtld) { 1205 Needed_Entry *nep = NEW(Needed_Entry); 1206 nep->name = dynp->d_un.d_val; 1207 nep->obj = NULL; 1208 nep->next = NULL; 1209 1210 *needed_tail = nep; 1211 needed_tail = &nep->next; 1212 } 1213 break; 1214 1215 case DT_FILTER: 1216 if (!obj->rtld) { 1217 Needed_Entry *nep = NEW(Needed_Entry); 1218 nep->name = dynp->d_un.d_val; 1219 nep->obj = NULL; 1220 nep->next = NULL; 1221 1222 *needed_filtees_tail = nep; 1223 needed_filtees_tail = &nep->next; 1224 1225 if (obj->linkmap.l_refname == NULL) 1226 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1227 } 1228 break; 1229 1230 case DT_AUXILIARY: 1231 if (!obj->rtld) { 1232 Needed_Entry *nep = NEW(Needed_Entry); 1233 nep->name = dynp->d_un.d_val; 1234 nep->obj = NULL; 1235 nep->next = NULL; 1236 1237 *needed_aux_filtees_tail = nep; 1238 needed_aux_filtees_tail = &nep->next; 1239 } 1240 break; 1241 1242 case DT_PLTGOT: 1243 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1244 break; 1245 1246 case DT_TEXTREL: 1247 obj->textrel = true; 1248 break; 1249 1250 case DT_SYMBOLIC: 1251 obj->symbolic = true; 1252 break; 1253 1254 case DT_RPATH: 1255 /* 1256 * We have to wait until later to process this, because we 1257 * might not have gotten the address of the string table yet. 1258 */ 1259 *dyn_rpath = dynp; 1260 break; 1261 1262 case DT_SONAME: 1263 *dyn_soname = dynp; 1264 break; 1265 1266 case DT_RUNPATH: 1267 *dyn_runpath = dynp; 1268 break; 1269 1270 case DT_INIT: 1271 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1272 break; 1273 1274 case DT_PREINIT_ARRAY: 1275 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1276 break; 1277 1278 case DT_PREINIT_ARRAYSZ: 1279 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1280 break; 1281 1282 case DT_INIT_ARRAY: 1283 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1284 break; 1285 1286 case DT_INIT_ARRAYSZ: 1287 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1288 break; 1289 1290 case DT_FINI: 1291 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1292 break; 1293 1294 case DT_FINI_ARRAY: 1295 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1296 break; 1297 1298 case DT_FINI_ARRAYSZ: 1299 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1300 break; 1301 1302 /* 1303 * Don't process DT_DEBUG on MIPS as the dynamic section 1304 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1305 */ 1306 1307 #ifndef __mips__ 1308 case DT_DEBUG: 1309 if (!early) 1310 dbg("Filling in DT_DEBUG entry"); 1311 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1312 break; 1313 #endif 1314 1315 case DT_FLAGS: 1316 if (dynp->d_un.d_val & DF_ORIGIN) 1317 obj->z_origin = true; 1318 if (dynp->d_un.d_val & DF_SYMBOLIC) 1319 obj->symbolic = true; 1320 if (dynp->d_un.d_val & DF_TEXTREL) 1321 obj->textrel = true; 1322 if (dynp->d_un.d_val & DF_BIND_NOW) 1323 obj->bind_now = true; 1324 if (dynp->d_un.d_val & DF_STATIC_TLS) 1325 obj->static_tls = true; 1326 break; 1327 #ifdef __mips__ 1328 case DT_MIPS_LOCAL_GOTNO: 1329 obj->local_gotno = dynp->d_un.d_val; 1330 break; 1331 1332 case DT_MIPS_SYMTABNO: 1333 obj->symtabno = dynp->d_un.d_val; 1334 break; 1335 1336 case DT_MIPS_GOTSYM: 1337 obj->gotsym = dynp->d_un.d_val; 1338 break; 1339 1340 case DT_MIPS_RLD_MAP: 1341 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1342 break; 1343 1344 case DT_MIPS_RLD_MAP_REL: 1345 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1346 // section relative to the address of the tag itself. 1347 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1348 (Elf_Addr) &r_debug; 1349 break; 1350 1351 case DT_MIPS_PLTGOT: 1352 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1353 dynp->d_un.d_ptr); 1354 break; 1355 1356 #endif 1357 1358 #ifdef __powerpc__ 1359 #ifdef __powerpc64__ 1360 case DT_PPC64_GLINK: 1361 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1362 break; 1363 #else 1364 case DT_PPC_GOT: 1365 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1366 break; 1367 #endif 1368 #endif 1369 1370 case DT_FLAGS_1: 1371 if (dynp->d_un.d_val & DF_1_NOOPEN) 1372 obj->z_noopen = true; 1373 if (dynp->d_un.d_val & DF_1_ORIGIN) 1374 obj->z_origin = true; 1375 if (dynp->d_un.d_val & DF_1_GLOBAL) 1376 obj->z_global = true; 1377 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1378 obj->bind_now = true; 1379 if (dynp->d_un.d_val & DF_1_NODELETE) 1380 obj->z_nodelete = true; 1381 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1382 obj->z_loadfltr = true; 1383 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1384 obj->z_interpose = true; 1385 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1386 obj->z_nodeflib = true; 1387 if (dynp->d_un.d_val & DF_1_PIE) 1388 obj->z_pie = true; 1389 break; 1390 1391 default: 1392 if (!early) { 1393 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1394 (long)dynp->d_tag); 1395 } 1396 break; 1397 } 1398 } 1399 1400 obj->traced = false; 1401 1402 if (plttype == DT_RELA) { 1403 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1404 obj->pltrel = NULL; 1405 obj->pltrelasize = obj->pltrelsize; 1406 obj->pltrelsize = 0; 1407 } 1408 1409 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1410 if (obj->valid_hash_sysv) 1411 obj->dynsymcount = obj->nchains; 1412 else if (obj->valid_hash_gnu) { 1413 obj->dynsymcount = 0; 1414 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1415 if (obj->buckets_gnu[bkt] == 0) 1416 continue; 1417 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1418 do 1419 obj->dynsymcount++; 1420 while ((*hashval++ & 1u) == 0); 1421 } 1422 obj->dynsymcount += obj->symndx_gnu; 1423 } 1424 1425 if (obj->linkmap.l_refname != NULL) 1426 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1427 linkmap.l_refname; 1428 } 1429 1430 static bool 1431 obj_resolve_origin(Obj_Entry *obj) 1432 { 1433 1434 if (obj->origin_path != NULL) 1435 return (true); 1436 obj->origin_path = xmalloc(PATH_MAX); 1437 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1438 } 1439 1440 static bool 1441 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1442 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1443 { 1444 1445 if (obj->z_origin && !obj_resolve_origin(obj)) 1446 return (false); 1447 1448 if (dyn_runpath != NULL) { 1449 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1450 obj->runpath = origin_subst(obj, obj->runpath); 1451 } else if (dyn_rpath != NULL) { 1452 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1453 obj->rpath = origin_subst(obj, obj->rpath); 1454 } 1455 if (dyn_soname != NULL) 1456 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1457 return (true); 1458 } 1459 1460 static bool 1461 digest_dynamic(Obj_Entry *obj, int early) 1462 { 1463 const Elf_Dyn *dyn_rpath; 1464 const Elf_Dyn *dyn_soname; 1465 const Elf_Dyn *dyn_runpath; 1466 1467 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1468 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1469 } 1470 1471 /* 1472 * Process a shared object's program header. This is used only for the 1473 * main program, when the kernel has already loaded the main program 1474 * into memory before calling the dynamic linker. It creates and 1475 * returns an Obj_Entry structure. 1476 */ 1477 static Obj_Entry * 1478 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1479 { 1480 Obj_Entry *obj; 1481 const Elf_Phdr *phlimit = phdr + phnum; 1482 const Elf_Phdr *ph; 1483 Elf_Addr note_start, note_end; 1484 int nsegs = 0; 1485 1486 obj = obj_new(); 1487 for (ph = phdr; ph < phlimit; ph++) { 1488 if (ph->p_type != PT_PHDR) 1489 continue; 1490 1491 obj->phdr = phdr; 1492 obj->phsize = ph->p_memsz; 1493 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1494 break; 1495 } 1496 1497 obj->stack_flags = PF_X | PF_R | PF_W; 1498 1499 for (ph = phdr; ph < phlimit; ph++) { 1500 switch (ph->p_type) { 1501 1502 case PT_INTERP: 1503 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1504 break; 1505 1506 case PT_LOAD: 1507 if (nsegs == 0) { /* First load segment */ 1508 obj->vaddrbase = trunc_page(ph->p_vaddr); 1509 obj->mapbase = obj->vaddrbase + obj->relocbase; 1510 } else { /* Last load segment */ 1511 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1512 obj->vaddrbase; 1513 } 1514 nsegs++; 1515 break; 1516 1517 case PT_DYNAMIC: 1518 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1519 break; 1520 1521 case PT_TLS: 1522 obj->tlsindex = 1; 1523 obj->tlssize = ph->p_memsz; 1524 obj->tlsalign = ph->p_align; 1525 obj->tlsinitsize = ph->p_filesz; 1526 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1527 obj->tlspoffset = ph->p_offset; 1528 break; 1529 1530 case PT_GNU_STACK: 1531 obj->stack_flags = ph->p_flags; 1532 break; 1533 1534 case PT_GNU_RELRO: 1535 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1536 obj->relro_size = round_page(ph->p_memsz); 1537 break; 1538 1539 case PT_NOTE: 1540 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1541 note_end = note_start + ph->p_filesz; 1542 digest_notes(obj, note_start, note_end); 1543 break; 1544 } 1545 } 1546 if (nsegs < 1) { 1547 _rtld_error("%s: too few PT_LOAD segments", path); 1548 return NULL; 1549 } 1550 1551 obj->entry = entry; 1552 return obj; 1553 } 1554 1555 void 1556 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1557 { 1558 const Elf_Note *note; 1559 const char *note_name; 1560 uintptr_t p; 1561 1562 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1563 note = (const Elf_Note *)((const char *)(note + 1) + 1564 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1565 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1566 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1567 note->n_descsz != sizeof(int32_t)) 1568 continue; 1569 if (note->n_type != NT_FREEBSD_ABI_TAG && 1570 note->n_type != NT_FREEBSD_FEATURE_CTL && 1571 note->n_type != NT_FREEBSD_NOINIT_TAG) 1572 continue; 1573 note_name = (const char *)(note + 1); 1574 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1575 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1576 continue; 1577 switch (note->n_type) { 1578 case NT_FREEBSD_ABI_TAG: 1579 /* FreeBSD osrel note */ 1580 p = (uintptr_t)(note + 1); 1581 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1582 obj->osrel = *(const int32_t *)(p); 1583 dbg("note osrel %d", obj->osrel); 1584 break; 1585 case NT_FREEBSD_FEATURE_CTL: 1586 /* FreeBSD ABI feature control note */ 1587 p = (uintptr_t)(note + 1); 1588 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1589 obj->fctl0 = *(const uint32_t *)(p); 1590 dbg("note fctl0 %#x", obj->fctl0); 1591 break; 1592 case NT_FREEBSD_NOINIT_TAG: 1593 /* FreeBSD 'crt does not call init' note */ 1594 obj->crt_no_init = true; 1595 dbg("note crt_no_init"); 1596 break; 1597 } 1598 } 1599 } 1600 1601 static Obj_Entry * 1602 dlcheck(void *handle) 1603 { 1604 Obj_Entry *obj; 1605 1606 TAILQ_FOREACH(obj, &obj_list, next) { 1607 if (obj == (Obj_Entry *) handle) 1608 break; 1609 } 1610 1611 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1612 _rtld_error("Invalid shared object handle %p", handle); 1613 return NULL; 1614 } 1615 return obj; 1616 } 1617 1618 /* 1619 * If the given object is already in the donelist, return true. Otherwise 1620 * add the object to the list and return false. 1621 */ 1622 static bool 1623 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1624 { 1625 unsigned int i; 1626 1627 for (i = 0; i < dlp->num_used; i++) 1628 if (dlp->objs[i] == obj) 1629 return true; 1630 /* 1631 * Our donelist allocation should always be sufficient. But if 1632 * our threads locking isn't working properly, more shared objects 1633 * could have been loaded since we allocated the list. That should 1634 * never happen, but we'll handle it properly just in case it does. 1635 */ 1636 if (dlp->num_used < dlp->num_alloc) 1637 dlp->objs[dlp->num_used++] = obj; 1638 return false; 1639 } 1640 1641 /* 1642 * Hash function for symbol table lookup. Don't even think about changing 1643 * this. It is specified by the System V ABI. 1644 */ 1645 unsigned long 1646 elf_hash(const char *name) 1647 { 1648 const unsigned char *p = (const unsigned char *) name; 1649 unsigned long h = 0; 1650 unsigned long g; 1651 1652 while (*p != '\0') { 1653 h = (h << 4) + *p++; 1654 if ((g = h & 0xf0000000) != 0) 1655 h ^= g >> 24; 1656 h &= ~g; 1657 } 1658 return h; 1659 } 1660 1661 /* 1662 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1663 * unsigned in case it's implemented with a wider type. 1664 */ 1665 static uint32_t 1666 gnu_hash(const char *s) 1667 { 1668 uint32_t h; 1669 unsigned char c; 1670 1671 h = 5381; 1672 for (c = *s; c != '\0'; c = *++s) 1673 h = h * 33 + c; 1674 return (h & 0xffffffff); 1675 } 1676 1677 1678 /* 1679 * Find the library with the given name, and return its full pathname. 1680 * The returned string is dynamically allocated. Generates an error 1681 * message and returns NULL if the library cannot be found. 1682 * 1683 * If the second argument is non-NULL, then it refers to an already- 1684 * loaded shared object, whose library search path will be searched. 1685 * 1686 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1687 * descriptor (which is close-on-exec) will be passed out via the third 1688 * argument. 1689 * 1690 * The search order is: 1691 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1692 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1693 * LD_LIBRARY_PATH 1694 * DT_RUNPATH in the referencing file 1695 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1696 * from list) 1697 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1698 * 1699 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1700 */ 1701 static char * 1702 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1703 { 1704 char *pathname, *refobj_path; 1705 const char *name; 1706 bool nodeflib, objgiven; 1707 1708 objgiven = refobj != NULL; 1709 1710 if (libmap_disable || !objgiven || 1711 (name = lm_find(refobj->path, xname)) == NULL) 1712 name = xname; 1713 1714 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1715 if (name[0] != '/' && !trust) { 1716 _rtld_error("Absolute pathname required " 1717 "for shared object \"%s\"", name); 1718 return (NULL); 1719 } 1720 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1721 __DECONST(char *, name))); 1722 } 1723 1724 dbg(" Searching for \"%s\"", name); 1725 refobj_path = objgiven ? refobj->path : NULL; 1726 1727 /* 1728 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1729 * back to pre-conforming behaviour if user requested so with 1730 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1731 * nodeflib. 1732 */ 1733 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1734 pathname = search_library_path(name, ld_library_path, 1735 refobj_path, fdp); 1736 if (pathname != NULL) 1737 return (pathname); 1738 if (refobj != NULL) { 1739 pathname = search_library_path(name, refobj->rpath, 1740 refobj_path, fdp); 1741 if (pathname != NULL) 1742 return (pathname); 1743 } 1744 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1745 if (pathname != NULL) 1746 return (pathname); 1747 pathname = search_library_path(name, gethints(false), 1748 refobj_path, fdp); 1749 if (pathname != NULL) 1750 return (pathname); 1751 pathname = search_library_path(name, ld_standard_library_path, 1752 refobj_path, fdp); 1753 if (pathname != NULL) 1754 return (pathname); 1755 } else { 1756 nodeflib = objgiven ? refobj->z_nodeflib : false; 1757 if (objgiven) { 1758 pathname = search_library_path(name, refobj->rpath, 1759 refobj->path, fdp); 1760 if (pathname != NULL) 1761 return (pathname); 1762 } 1763 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1764 pathname = search_library_path(name, obj_main->rpath, 1765 refobj_path, fdp); 1766 if (pathname != NULL) 1767 return (pathname); 1768 } 1769 pathname = search_library_path(name, ld_library_path, 1770 refobj_path, fdp); 1771 if (pathname != NULL) 1772 return (pathname); 1773 if (objgiven) { 1774 pathname = search_library_path(name, refobj->runpath, 1775 refobj_path, fdp); 1776 if (pathname != NULL) 1777 return (pathname); 1778 } 1779 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1780 if (pathname != NULL) 1781 return (pathname); 1782 pathname = search_library_path(name, gethints(nodeflib), 1783 refobj_path, fdp); 1784 if (pathname != NULL) 1785 return (pathname); 1786 if (objgiven && !nodeflib) { 1787 pathname = search_library_path(name, 1788 ld_standard_library_path, refobj_path, fdp); 1789 if (pathname != NULL) 1790 return (pathname); 1791 } 1792 } 1793 1794 if (objgiven && refobj->path != NULL) { 1795 _rtld_error("Shared object \"%s\" not found, " 1796 "required by \"%s\"", name, basename(refobj->path)); 1797 } else { 1798 _rtld_error("Shared object \"%s\" not found", name); 1799 } 1800 return (NULL); 1801 } 1802 1803 /* 1804 * Given a symbol number in a referencing object, find the corresponding 1805 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1806 * no definition was found. Returns a pointer to the Obj_Entry of the 1807 * defining object via the reference parameter DEFOBJ_OUT. 1808 */ 1809 const Elf_Sym * 1810 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1811 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1812 RtldLockState *lockstate) 1813 { 1814 const Elf_Sym *ref; 1815 const Elf_Sym *def; 1816 const Obj_Entry *defobj; 1817 const Ver_Entry *ve; 1818 SymLook req; 1819 const char *name; 1820 int res; 1821 1822 /* 1823 * If we have already found this symbol, get the information from 1824 * the cache. 1825 */ 1826 if (symnum >= refobj->dynsymcount) 1827 return NULL; /* Bad object */ 1828 if (cache != NULL && cache[symnum].sym != NULL) { 1829 *defobj_out = cache[symnum].obj; 1830 return cache[symnum].sym; 1831 } 1832 1833 ref = refobj->symtab + symnum; 1834 name = refobj->strtab + ref->st_name; 1835 def = NULL; 1836 defobj = NULL; 1837 ve = NULL; 1838 1839 /* 1840 * We don't have to do a full scale lookup if the symbol is local. 1841 * We know it will bind to the instance in this load module; to 1842 * which we already have a pointer (ie ref). By not doing a lookup, 1843 * we not only improve performance, but it also avoids unresolvable 1844 * symbols when local symbols are not in the hash table. This has 1845 * been seen with the ia64 toolchain. 1846 */ 1847 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1848 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1849 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1850 symnum); 1851 } 1852 symlook_init(&req, name); 1853 req.flags = flags; 1854 ve = req.ventry = fetch_ventry(refobj, symnum); 1855 req.lockstate = lockstate; 1856 res = symlook_default(&req, refobj); 1857 if (res == 0) { 1858 def = req.sym_out; 1859 defobj = req.defobj_out; 1860 } 1861 } else { 1862 def = ref; 1863 defobj = refobj; 1864 } 1865 1866 /* 1867 * If we found no definition and the reference is weak, treat the 1868 * symbol as having the value zero. 1869 */ 1870 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1871 def = &sym_zero; 1872 defobj = obj_main; 1873 } 1874 1875 if (def != NULL) { 1876 *defobj_out = defobj; 1877 /* Record the information in the cache to avoid subsequent lookups. */ 1878 if (cache != NULL) { 1879 cache[symnum].sym = def; 1880 cache[symnum].obj = defobj; 1881 } 1882 } else { 1883 if (refobj != &obj_rtld) 1884 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1885 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1886 } 1887 return def; 1888 } 1889 1890 /* 1891 * Return the search path from the ldconfig hints file, reading it if 1892 * necessary. If nostdlib is true, then the default search paths are 1893 * not added to result. 1894 * 1895 * Returns NULL if there are problems with the hints file, 1896 * or if the search path there is empty. 1897 */ 1898 static const char * 1899 gethints(bool nostdlib) 1900 { 1901 static char *filtered_path; 1902 static const char *hints; 1903 static struct elfhints_hdr hdr; 1904 struct fill_search_info_args sargs, hargs; 1905 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1906 struct dl_serpath *SLPpath, *hintpath; 1907 char *p; 1908 struct stat hint_stat; 1909 unsigned int SLPndx, hintndx, fndx, fcount; 1910 int fd; 1911 size_t flen; 1912 uint32_t dl; 1913 bool skip; 1914 1915 /* First call, read the hints file */ 1916 if (hints == NULL) { 1917 /* Keep from trying again in case the hints file is bad. */ 1918 hints = ""; 1919 1920 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1921 return (NULL); 1922 1923 /* 1924 * Check of hdr.dirlistlen value against type limit 1925 * intends to pacify static analyzers. Further 1926 * paranoia leads to checks that dirlist is fully 1927 * contained in the file range. 1928 */ 1929 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1930 hdr.magic != ELFHINTS_MAGIC || 1931 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1932 fstat(fd, &hint_stat) == -1) { 1933 cleanup1: 1934 close(fd); 1935 hdr.dirlistlen = 0; 1936 return (NULL); 1937 } 1938 dl = hdr.strtab; 1939 if (dl + hdr.dirlist < dl) 1940 goto cleanup1; 1941 dl += hdr.dirlist; 1942 if (dl + hdr.dirlistlen < dl) 1943 goto cleanup1; 1944 dl += hdr.dirlistlen; 1945 if (dl > hint_stat.st_size) 1946 goto cleanup1; 1947 p = xmalloc(hdr.dirlistlen + 1); 1948 if (pread(fd, p, hdr.dirlistlen + 1, 1949 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1950 p[hdr.dirlistlen] != '\0') { 1951 free(p); 1952 goto cleanup1; 1953 } 1954 hints = p; 1955 close(fd); 1956 } 1957 1958 /* 1959 * If caller agreed to receive list which includes the default 1960 * paths, we are done. Otherwise, if we still did not 1961 * calculated filtered result, do it now. 1962 */ 1963 if (!nostdlib) 1964 return (hints[0] != '\0' ? hints : NULL); 1965 if (filtered_path != NULL) 1966 goto filt_ret; 1967 1968 /* 1969 * Obtain the list of all configured search paths, and the 1970 * list of the default paths. 1971 * 1972 * First estimate the size of the results. 1973 */ 1974 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1975 smeta.dls_cnt = 0; 1976 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1977 hmeta.dls_cnt = 0; 1978 1979 sargs.request = RTLD_DI_SERINFOSIZE; 1980 sargs.serinfo = &smeta; 1981 hargs.request = RTLD_DI_SERINFOSIZE; 1982 hargs.serinfo = &hmeta; 1983 1984 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1985 &sargs); 1986 path_enumerate(hints, fill_search_info, NULL, &hargs); 1987 1988 SLPinfo = xmalloc(smeta.dls_size); 1989 hintinfo = xmalloc(hmeta.dls_size); 1990 1991 /* 1992 * Next fetch both sets of paths. 1993 */ 1994 sargs.request = RTLD_DI_SERINFO; 1995 sargs.serinfo = SLPinfo; 1996 sargs.serpath = &SLPinfo->dls_serpath[0]; 1997 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1998 1999 hargs.request = RTLD_DI_SERINFO; 2000 hargs.serinfo = hintinfo; 2001 hargs.serpath = &hintinfo->dls_serpath[0]; 2002 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2003 2004 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2005 &sargs); 2006 path_enumerate(hints, fill_search_info, NULL, &hargs); 2007 2008 /* 2009 * Now calculate the difference between two sets, by excluding 2010 * standard paths from the full set. 2011 */ 2012 fndx = 0; 2013 fcount = 0; 2014 filtered_path = xmalloc(hdr.dirlistlen + 1); 2015 hintpath = &hintinfo->dls_serpath[0]; 2016 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2017 skip = false; 2018 SLPpath = &SLPinfo->dls_serpath[0]; 2019 /* 2020 * Check each standard path against current. 2021 */ 2022 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2023 /* matched, skip the path */ 2024 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2025 skip = true; 2026 break; 2027 } 2028 } 2029 if (skip) 2030 continue; 2031 /* 2032 * Not matched against any standard path, add the path 2033 * to result. Separate consequtive paths with ':'. 2034 */ 2035 if (fcount > 0) { 2036 filtered_path[fndx] = ':'; 2037 fndx++; 2038 } 2039 fcount++; 2040 flen = strlen(hintpath->dls_name); 2041 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2042 fndx += flen; 2043 } 2044 filtered_path[fndx] = '\0'; 2045 2046 free(SLPinfo); 2047 free(hintinfo); 2048 2049 filt_ret: 2050 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2051 } 2052 2053 static void 2054 init_dag(Obj_Entry *root) 2055 { 2056 const Needed_Entry *needed; 2057 const Objlist_Entry *elm; 2058 DoneList donelist; 2059 2060 if (root->dag_inited) 2061 return; 2062 donelist_init(&donelist); 2063 2064 /* Root object belongs to own DAG. */ 2065 objlist_push_tail(&root->dldags, root); 2066 objlist_push_tail(&root->dagmembers, root); 2067 donelist_check(&donelist, root); 2068 2069 /* 2070 * Add dependencies of root object to DAG in breadth order 2071 * by exploiting the fact that each new object get added 2072 * to the tail of the dagmembers list. 2073 */ 2074 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2075 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2076 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2077 continue; 2078 objlist_push_tail(&needed->obj->dldags, root); 2079 objlist_push_tail(&root->dagmembers, needed->obj); 2080 } 2081 } 2082 root->dag_inited = true; 2083 } 2084 2085 static void 2086 init_marker(Obj_Entry *marker) 2087 { 2088 2089 bzero(marker, sizeof(*marker)); 2090 marker->marker = true; 2091 } 2092 2093 Obj_Entry * 2094 globallist_curr(const Obj_Entry *obj) 2095 { 2096 2097 for (;;) { 2098 if (obj == NULL) 2099 return (NULL); 2100 if (!obj->marker) 2101 return (__DECONST(Obj_Entry *, obj)); 2102 obj = TAILQ_PREV(obj, obj_entry_q, next); 2103 } 2104 } 2105 2106 Obj_Entry * 2107 globallist_next(const Obj_Entry *obj) 2108 { 2109 2110 for (;;) { 2111 obj = TAILQ_NEXT(obj, next); 2112 if (obj == NULL) 2113 return (NULL); 2114 if (!obj->marker) 2115 return (__DECONST(Obj_Entry *, obj)); 2116 } 2117 } 2118 2119 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2120 static void 2121 hold_object(Obj_Entry *obj) 2122 { 2123 2124 obj->holdcount++; 2125 } 2126 2127 static void 2128 unhold_object(Obj_Entry *obj) 2129 { 2130 2131 assert(obj->holdcount > 0); 2132 if (--obj->holdcount == 0 && obj->unholdfree) 2133 release_object(obj); 2134 } 2135 2136 static void 2137 process_z(Obj_Entry *root) 2138 { 2139 const Objlist_Entry *elm; 2140 Obj_Entry *obj; 2141 2142 /* 2143 * Walk over object DAG and process every dependent object 2144 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2145 * to grow their own DAG. 2146 * 2147 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2148 * symlook_global() to work. 2149 * 2150 * For DF_1_NODELETE, the DAG should have its reference upped. 2151 */ 2152 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2153 obj = elm->obj; 2154 if (obj == NULL) 2155 continue; 2156 if (obj->z_nodelete && !obj->ref_nodel) { 2157 dbg("obj %s -z nodelete", obj->path); 2158 init_dag(obj); 2159 ref_dag(obj); 2160 obj->ref_nodel = true; 2161 } 2162 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2163 dbg("obj %s -z global", obj->path); 2164 objlist_push_tail(&list_global, obj); 2165 init_dag(obj); 2166 } 2167 } 2168 } 2169 2170 static void 2171 parse_rtld_phdr(Obj_Entry *obj) 2172 { 2173 const Elf_Phdr *ph; 2174 Elf_Addr note_start, note_end; 2175 2176 obj->stack_flags = PF_X | PF_R | PF_W; 2177 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2178 obj->phsize; ph++) { 2179 switch (ph->p_type) { 2180 case PT_GNU_STACK: 2181 obj->stack_flags = ph->p_flags; 2182 break; 2183 case PT_GNU_RELRO: 2184 obj->relro_page = obj->relocbase + 2185 trunc_page(ph->p_vaddr); 2186 obj->relro_size = round_page(ph->p_memsz); 2187 break; 2188 case PT_NOTE: 2189 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2190 note_end = note_start + ph->p_filesz; 2191 digest_notes(obj, note_start, note_end); 2192 break; 2193 } 2194 } 2195 } 2196 2197 /* 2198 * Initialize the dynamic linker. The argument is the address at which 2199 * the dynamic linker has been mapped into memory. The primary task of 2200 * this function is to relocate the dynamic linker. 2201 */ 2202 static void 2203 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2204 { 2205 Obj_Entry objtmp; /* Temporary rtld object */ 2206 const Elf_Ehdr *ehdr; 2207 const Elf_Dyn *dyn_rpath; 2208 const Elf_Dyn *dyn_soname; 2209 const Elf_Dyn *dyn_runpath; 2210 2211 #ifdef RTLD_INIT_PAGESIZES_EARLY 2212 /* The page size is required by the dynamic memory allocator. */ 2213 init_pagesizes(aux_info); 2214 #endif 2215 2216 /* 2217 * Conjure up an Obj_Entry structure for the dynamic linker. 2218 * 2219 * The "path" member can't be initialized yet because string constants 2220 * cannot yet be accessed. Below we will set it correctly. 2221 */ 2222 memset(&objtmp, 0, sizeof(objtmp)); 2223 objtmp.path = NULL; 2224 objtmp.rtld = true; 2225 objtmp.mapbase = mapbase; 2226 #ifdef PIC 2227 objtmp.relocbase = mapbase; 2228 #endif 2229 2230 objtmp.dynamic = rtld_dynamic(&objtmp); 2231 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2232 assert(objtmp.needed == NULL); 2233 #if !defined(__mips__) 2234 /* MIPS has a bogus DT_TEXTREL. */ 2235 assert(!objtmp.textrel); 2236 #endif 2237 /* 2238 * Temporarily put the dynamic linker entry into the object list, so 2239 * that symbols can be found. 2240 */ 2241 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2242 2243 ehdr = (Elf_Ehdr *)mapbase; 2244 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2245 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2246 2247 /* Initialize the object list. */ 2248 TAILQ_INIT(&obj_list); 2249 2250 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2251 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2252 2253 #ifndef RTLD_INIT_PAGESIZES_EARLY 2254 /* The page size is required by the dynamic memory allocator. */ 2255 init_pagesizes(aux_info); 2256 #endif 2257 2258 if (aux_info[AT_OSRELDATE] != NULL) 2259 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2260 2261 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2262 2263 /* Replace the path with a dynamically allocated copy. */ 2264 obj_rtld.path = xstrdup(ld_path_rtld); 2265 2266 parse_rtld_phdr(&obj_rtld); 2267 obj_enforce_relro(&obj_rtld); 2268 2269 r_debug.r_version = R_DEBUG_VERSION; 2270 r_debug.r_brk = r_debug_state; 2271 r_debug.r_state = RT_CONSISTENT; 2272 r_debug.r_ldbase = obj_rtld.relocbase; 2273 } 2274 2275 /* 2276 * Retrieve the array of supported page sizes. The kernel provides the page 2277 * sizes in increasing order. 2278 */ 2279 static void 2280 init_pagesizes(Elf_Auxinfo **aux_info) 2281 { 2282 static size_t psa[MAXPAGESIZES]; 2283 int mib[2]; 2284 size_t len, size; 2285 2286 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2287 NULL) { 2288 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2289 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2290 } else { 2291 len = 2; 2292 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2293 size = sizeof(psa); 2294 else { 2295 /* As a fallback, retrieve the base page size. */ 2296 size = sizeof(psa[0]); 2297 if (aux_info[AT_PAGESZ] != NULL) { 2298 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2299 goto psa_filled; 2300 } else { 2301 mib[0] = CTL_HW; 2302 mib[1] = HW_PAGESIZE; 2303 len = 2; 2304 } 2305 } 2306 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2307 _rtld_error("sysctl for hw.pagesize(s) failed"); 2308 rtld_die(); 2309 } 2310 psa_filled: 2311 pagesizes = psa; 2312 } 2313 npagesizes = size / sizeof(pagesizes[0]); 2314 /* Discard any invalid entries at the end of the array. */ 2315 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2316 npagesizes--; 2317 } 2318 2319 /* 2320 * Add the init functions from a needed object list (and its recursive 2321 * needed objects) to "list". This is not used directly; it is a helper 2322 * function for initlist_add_objects(). The write lock must be held 2323 * when this function is called. 2324 */ 2325 static void 2326 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2327 { 2328 /* Recursively process the successor needed objects. */ 2329 if (needed->next != NULL) 2330 initlist_add_neededs(needed->next, list); 2331 2332 /* Process the current needed object. */ 2333 if (needed->obj != NULL) 2334 initlist_add_objects(needed->obj, needed->obj, list); 2335 } 2336 2337 /* 2338 * Scan all of the DAGs rooted in the range of objects from "obj" to 2339 * "tail" and add their init functions to "list". This recurses over 2340 * the DAGs and ensure the proper init ordering such that each object's 2341 * needed libraries are initialized before the object itself. At the 2342 * same time, this function adds the objects to the global finalization 2343 * list "list_fini" in the opposite order. The write lock must be 2344 * held when this function is called. 2345 */ 2346 static void 2347 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2348 { 2349 Obj_Entry *nobj; 2350 2351 if (obj->init_scanned || obj->init_done) 2352 return; 2353 obj->init_scanned = true; 2354 2355 /* Recursively process the successor objects. */ 2356 nobj = globallist_next(obj); 2357 if (nobj != NULL && obj != tail) 2358 initlist_add_objects(nobj, tail, list); 2359 2360 /* Recursively process the needed objects. */ 2361 if (obj->needed != NULL) 2362 initlist_add_neededs(obj->needed, list); 2363 if (obj->needed_filtees != NULL) 2364 initlist_add_neededs(obj->needed_filtees, list); 2365 if (obj->needed_aux_filtees != NULL) 2366 initlist_add_neededs(obj->needed_aux_filtees, list); 2367 2368 /* Add the object to the init list. */ 2369 objlist_push_tail(list, obj); 2370 2371 /* Add the object to the global fini list in the reverse order. */ 2372 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2373 && !obj->on_fini_list) { 2374 objlist_push_head(&list_fini, obj); 2375 obj->on_fini_list = true; 2376 } 2377 } 2378 2379 #ifndef FPTR_TARGET 2380 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2381 #endif 2382 2383 static void 2384 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2385 { 2386 Needed_Entry *needed, *needed1; 2387 2388 for (needed = n; needed != NULL; needed = needed->next) { 2389 if (needed->obj != NULL) { 2390 dlclose_locked(needed->obj, lockstate); 2391 needed->obj = NULL; 2392 } 2393 } 2394 for (needed = n; needed != NULL; needed = needed1) { 2395 needed1 = needed->next; 2396 free(needed); 2397 } 2398 } 2399 2400 static void 2401 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2402 { 2403 2404 free_needed_filtees(obj->needed_filtees, lockstate); 2405 obj->needed_filtees = NULL; 2406 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2407 obj->needed_aux_filtees = NULL; 2408 obj->filtees_loaded = false; 2409 } 2410 2411 static void 2412 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2413 RtldLockState *lockstate) 2414 { 2415 2416 for (; needed != NULL; needed = needed->next) { 2417 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2418 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2419 RTLD_LOCAL, lockstate); 2420 } 2421 } 2422 2423 static void 2424 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2425 { 2426 2427 lock_restart_for_upgrade(lockstate); 2428 if (!obj->filtees_loaded) { 2429 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2430 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2431 obj->filtees_loaded = true; 2432 } 2433 } 2434 2435 static int 2436 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2437 { 2438 Obj_Entry *obj1; 2439 2440 for (; needed != NULL; needed = needed->next) { 2441 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2442 flags & ~RTLD_LO_NOLOAD); 2443 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2444 return (-1); 2445 } 2446 return (0); 2447 } 2448 2449 /* 2450 * Given a shared object, traverse its list of needed objects, and load 2451 * each of them. Returns 0 on success. Generates an error message and 2452 * returns -1 on failure. 2453 */ 2454 static int 2455 load_needed_objects(Obj_Entry *first, int flags) 2456 { 2457 Obj_Entry *obj; 2458 2459 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2460 if (obj->marker) 2461 continue; 2462 if (process_needed(obj, obj->needed, flags) == -1) 2463 return (-1); 2464 } 2465 return (0); 2466 } 2467 2468 static int 2469 load_preload_objects(void) 2470 { 2471 char *p = ld_preload; 2472 Obj_Entry *obj; 2473 static const char delim[] = " \t:;"; 2474 2475 if (p == NULL) 2476 return 0; 2477 2478 p += strspn(p, delim); 2479 while (*p != '\0') { 2480 size_t len = strcspn(p, delim); 2481 char savech; 2482 2483 savech = p[len]; 2484 p[len] = '\0'; 2485 obj = load_object(p, -1, NULL, 0); 2486 if (obj == NULL) 2487 return -1; /* XXX - cleanup */ 2488 obj->z_interpose = true; 2489 p[len] = savech; 2490 p += len; 2491 p += strspn(p, delim); 2492 } 2493 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2494 return 0; 2495 } 2496 2497 static const char * 2498 printable_path(const char *path) 2499 { 2500 2501 return (path == NULL ? "<unknown>" : path); 2502 } 2503 2504 /* 2505 * Load a shared object into memory, if it is not already loaded. The 2506 * object may be specified by name or by user-supplied file descriptor 2507 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2508 * duplicate is. 2509 * 2510 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2511 * on failure. 2512 */ 2513 static Obj_Entry * 2514 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2515 { 2516 Obj_Entry *obj; 2517 int fd; 2518 struct stat sb; 2519 char *path; 2520 2521 fd = -1; 2522 if (name != NULL) { 2523 TAILQ_FOREACH(obj, &obj_list, next) { 2524 if (obj->marker || obj->doomed) 2525 continue; 2526 if (object_match_name(obj, name)) 2527 return (obj); 2528 } 2529 2530 path = find_library(name, refobj, &fd); 2531 if (path == NULL) 2532 return (NULL); 2533 } else 2534 path = NULL; 2535 2536 if (fd >= 0) { 2537 /* 2538 * search_library_pathfds() opens a fresh file descriptor for the 2539 * library, so there is no need to dup(). 2540 */ 2541 } else if (fd_u == -1) { 2542 /* 2543 * If we didn't find a match by pathname, or the name is not 2544 * supplied, open the file and check again by device and inode. 2545 * This avoids false mismatches caused by multiple links or ".." 2546 * in pathnames. 2547 * 2548 * To avoid a race, we open the file and use fstat() rather than 2549 * using stat(). 2550 */ 2551 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2552 _rtld_error("Cannot open \"%s\"", path); 2553 free(path); 2554 return (NULL); 2555 } 2556 } else { 2557 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2558 if (fd == -1) { 2559 _rtld_error("Cannot dup fd"); 2560 free(path); 2561 return (NULL); 2562 } 2563 } 2564 if (fstat(fd, &sb) == -1) { 2565 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2566 close(fd); 2567 free(path); 2568 return NULL; 2569 } 2570 TAILQ_FOREACH(obj, &obj_list, next) { 2571 if (obj->marker || obj->doomed) 2572 continue; 2573 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2574 break; 2575 } 2576 if (obj != NULL && name != NULL) { 2577 object_add_name(obj, name); 2578 free(path); 2579 close(fd); 2580 return obj; 2581 } 2582 if (flags & RTLD_LO_NOLOAD) { 2583 free(path); 2584 close(fd); 2585 return (NULL); 2586 } 2587 2588 /* First use of this object, so we must map it in */ 2589 obj = do_load_object(fd, name, path, &sb, flags); 2590 if (obj == NULL) 2591 free(path); 2592 close(fd); 2593 2594 return obj; 2595 } 2596 2597 static Obj_Entry * 2598 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2599 int flags) 2600 { 2601 Obj_Entry *obj; 2602 struct statfs fs; 2603 2604 /* 2605 * but first, make sure that environment variables haven't been 2606 * used to circumvent the noexec flag on a filesystem. 2607 */ 2608 if (dangerous_ld_env) { 2609 if (fstatfs(fd, &fs) != 0) { 2610 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2611 return NULL; 2612 } 2613 if (fs.f_flags & MNT_NOEXEC) { 2614 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2615 return NULL; 2616 } 2617 } 2618 dbg("loading \"%s\"", printable_path(path)); 2619 obj = map_object(fd, printable_path(path), sbp); 2620 if (obj == NULL) 2621 return NULL; 2622 2623 /* 2624 * If DT_SONAME is present in the object, digest_dynamic2 already 2625 * added it to the object names. 2626 */ 2627 if (name != NULL) 2628 object_add_name(obj, name); 2629 obj->path = path; 2630 if (!digest_dynamic(obj, 0)) 2631 goto errp; 2632 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2633 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2634 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2635 dbg("refusing to load PIE executable \"%s\"", obj->path); 2636 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2637 goto errp; 2638 } 2639 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2640 RTLD_LO_DLOPEN) { 2641 dbg("refusing to load non-loadable \"%s\"", obj->path); 2642 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2643 goto errp; 2644 } 2645 2646 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2647 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2648 obj_count++; 2649 obj_loads++; 2650 linkmap_add(obj); /* for GDB & dlinfo() */ 2651 max_stack_flags |= obj->stack_flags; 2652 2653 dbg(" %p .. %p: %s", obj->mapbase, 2654 obj->mapbase + obj->mapsize - 1, obj->path); 2655 if (obj->textrel) 2656 dbg(" WARNING: %s has impure text", obj->path); 2657 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2658 obj->path); 2659 2660 return (obj); 2661 2662 errp: 2663 munmap(obj->mapbase, obj->mapsize); 2664 obj_free(obj); 2665 return (NULL); 2666 } 2667 2668 static Obj_Entry * 2669 obj_from_addr(const void *addr) 2670 { 2671 Obj_Entry *obj; 2672 2673 TAILQ_FOREACH(obj, &obj_list, next) { 2674 if (obj->marker) 2675 continue; 2676 if (addr < (void *) obj->mapbase) 2677 continue; 2678 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2679 return obj; 2680 } 2681 return NULL; 2682 } 2683 2684 static void 2685 preinit_main(void) 2686 { 2687 Elf_Addr *preinit_addr; 2688 int index; 2689 2690 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2691 if (preinit_addr == NULL) 2692 return; 2693 2694 for (index = 0; index < obj_main->preinit_array_num; index++) { 2695 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2696 dbg("calling preinit function for %s at %p", obj_main->path, 2697 (void *)preinit_addr[index]); 2698 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2699 0, 0, obj_main->path); 2700 call_init_pointer(obj_main, preinit_addr[index]); 2701 } 2702 } 2703 } 2704 2705 /* 2706 * Call the finalization functions for each of the objects in "list" 2707 * belonging to the DAG of "root" and referenced once. If NULL "root" 2708 * is specified, every finalization function will be called regardless 2709 * of the reference count and the list elements won't be freed. All of 2710 * the objects are expected to have non-NULL fini functions. 2711 */ 2712 static void 2713 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2714 { 2715 Objlist_Entry *elm; 2716 char *saved_msg; 2717 Elf_Addr *fini_addr; 2718 int index; 2719 2720 assert(root == NULL || root->refcount == 1); 2721 2722 if (root != NULL) 2723 root->doomed = true; 2724 2725 /* 2726 * Preserve the current error message since a fini function might 2727 * call into the dynamic linker and overwrite it. 2728 */ 2729 saved_msg = errmsg_save(); 2730 do { 2731 STAILQ_FOREACH(elm, list, link) { 2732 if (root != NULL && (elm->obj->refcount != 1 || 2733 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2734 continue; 2735 /* Remove object from fini list to prevent recursive invocation. */ 2736 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2737 /* Ensure that new references cannot be acquired. */ 2738 elm->obj->doomed = true; 2739 2740 hold_object(elm->obj); 2741 lock_release(rtld_bind_lock, lockstate); 2742 /* 2743 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2744 * When this happens, DT_FINI_ARRAY is processed first. 2745 */ 2746 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2747 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2748 for (index = elm->obj->fini_array_num - 1; index >= 0; 2749 index--) { 2750 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2751 dbg("calling fini function for %s at %p", 2752 elm->obj->path, (void *)fini_addr[index]); 2753 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2754 (void *)fini_addr[index], 0, 0, elm->obj->path); 2755 call_initfini_pointer(elm->obj, fini_addr[index]); 2756 } 2757 } 2758 } 2759 if (elm->obj->fini != (Elf_Addr)NULL) { 2760 dbg("calling fini function for %s at %p", elm->obj->path, 2761 (void *)elm->obj->fini); 2762 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2763 0, 0, elm->obj->path); 2764 call_initfini_pointer(elm->obj, elm->obj->fini); 2765 } 2766 wlock_acquire(rtld_bind_lock, lockstate); 2767 unhold_object(elm->obj); 2768 /* No need to free anything if process is going down. */ 2769 if (root != NULL) 2770 free(elm); 2771 /* 2772 * We must restart the list traversal after every fini call 2773 * because a dlclose() call from the fini function or from 2774 * another thread might have modified the reference counts. 2775 */ 2776 break; 2777 } 2778 } while (elm != NULL); 2779 errmsg_restore(saved_msg); 2780 } 2781 2782 /* 2783 * Call the initialization functions for each of the objects in 2784 * "list". All of the objects are expected to have non-NULL init 2785 * functions. 2786 */ 2787 static void 2788 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2789 { 2790 Objlist_Entry *elm; 2791 Obj_Entry *obj; 2792 char *saved_msg; 2793 Elf_Addr *init_addr; 2794 void (*reg)(void (*)(void)); 2795 int index; 2796 2797 /* 2798 * Clean init_scanned flag so that objects can be rechecked and 2799 * possibly initialized earlier if any of vectors called below 2800 * cause the change by using dlopen. 2801 */ 2802 TAILQ_FOREACH(obj, &obj_list, next) { 2803 if (obj->marker) 2804 continue; 2805 obj->init_scanned = false; 2806 } 2807 2808 /* 2809 * Preserve the current error message since an init function might 2810 * call into the dynamic linker and overwrite it. 2811 */ 2812 saved_msg = errmsg_save(); 2813 STAILQ_FOREACH(elm, list, link) { 2814 if (elm->obj->init_done) /* Initialized early. */ 2815 continue; 2816 /* 2817 * Race: other thread might try to use this object before current 2818 * one completes the initialization. Not much can be done here 2819 * without better locking. 2820 */ 2821 elm->obj->init_done = true; 2822 hold_object(elm->obj); 2823 reg = NULL; 2824 if (elm->obj == obj_main && obj_main->crt_no_init) { 2825 reg = (void (*)(void (*)(void)))get_program_var_addr( 2826 "__libc_atexit", lockstate); 2827 } 2828 lock_release(rtld_bind_lock, lockstate); 2829 if (reg != NULL) { 2830 reg(rtld_exit); 2831 rtld_exit_ptr = rtld_nop_exit; 2832 } 2833 2834 /* 2835 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2836 * When this happens, DT_INIT is processed first. 2837 */ 2838 if (elm->obj->init != (Elf_Addr)NULL) { 2839 dbg("calling init function for %s at %p", elm->obj->path, 2840 (void *)elm->obj->init); 2841 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2842 0, 0, elm->obj->path); 2843 call_init_pointer(elm->obj, elm->obj->init); 2844 } 2845 init_addr = (Elf_Addr *)elm->obj->init_array; 2846 if (init_addr != NULL) { 2847 for (index = 0; index < elm->obj->init_array_num; index++) { 2848 if (init_addr[index] != 0 && init_addr[index] != 1) { 2849 dbg("calling init function for %s at %p", elm->obj->path, 2850 (void *)init_addr[index]); 2851 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2852 (void *)init_addr[index], 0, 0, elm->obj->path); 2853 call_init_pointer(elm->obj, init_addr[index]); 2854 } 2855 } 2856 } 2857 wlock_acquire(rtld_bind_lock, lockstate); 2858 unhold_object(elm->obj); 2859 } 2860 errmsg_restore(saved_msg); 2861 } 2862 2863 static void 2864 objlist_clear(Objlist *list) 2865 { 2866 Objlist_Entry *elm; 2867 2868 while (!STAILQ_EMPTY(list)) { 2869 elm = STAILQ_FIRST(list); 2870 STAILQ_REMOVE_HEAD(list, link); 2871 free(elm); 2872 } 2873 } 2874 2875 static Objlist_Entry * 2876 objlist_find(Objlist *list, const Obj_Entry *obj) 2877 { 2878 Objlist_Entry *elm; 2879 2880 STAILQ_FOREACH(elm, list, link) 2881 if (elm->obj == obj) 2882 return elm; 2883 return NULL; 2884 } 2885 2886 static void 2887 objlist_init(Objlist *list) 2888 { 2889 STAILQ_INIT(list); 2890 } 2891 2892 static void 2893 objlist_push_head(Objlist *list, Obj_Entry *obj) 2894 { 2895 Objlist_Entry *elm; 2896 2897 elm = NEW(Objlist_Entry); 2898 elm->obj = obj; 2899 STAILQ_INSERT_HEAD(list, elm, link); 2900 } 2901 2902 static void 2903 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2904 { 2905 Objlist_Entry *elm; 2906 2907 elm = NEW(Objlist_Entry); 2908 elm->obj = obj; 2909 STAILQ_INSERT_TAIL(list, elm, link); 2910 } 2911 2912 static void 2913 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2914 { 2915 Objlist_Entry *elm, *listelm; 2916 2917 STAILQ_FOREACH(listelm, list, link) { 2918 if (listelm->obj == listobj) 2919 break; 2920 } 2921 elm = NEW(Objlist_Entry); 2922 elm->obj = obj; 2923 if (listelm != NULL) 2924 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2925 else 2926 STAILQ_INSERT_TAIL(list, elm, link); 2927 } 2928 2929 static void 2930 objlist_remove(Objlist *list, Obj_Entry *obj) 2931 { 2932 Objlist_Entry *elm; 2933 2934 if ((elm = objlist_find(list, obj)) != NULL) { 2935 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2936 free(elm); 2937 } 2938 } 2939 2940 /* 2941 * Relocate dag rooted in the specified object. 2942 * Returns 0 on success, or -1 on failure. 2943 */ 2944 2945 static int 2946 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2947 int flags, RtldLockState *lockstate) 2948 { 2949 Objlist_Entry *elm; 2950 int error; 2951 2952 error = 0; 2953 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2954 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2955 lockstate); 2956 if (error == -1) 2957 break; 2958 } 2959 return (error); 2960 } 2961 2962 /* 2963 * Prepare for, or clean after, relocating an object marked with 2964 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2965 * segments are remapped read-write. After relocations are done, the 2966 * segment's permissions are returned back to the modes specified in 2967 * the phdrs. If any relocation happened, or always for wired 2968 * program, COW is triggered. 2969 */ 2970 static int 2971 reloc_textrel_prot(Obj_Entry *obj, bool before) 2972 { 2973 const Elf_Phdr *ph; 2974 void *base; 2975 size_t l, sz; 2976 int prot; 2977 2978 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2979 l--, ph++) { 2980 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2981 continue; 2982 base = obj->relocbase + trunc_page(ph->p_vaddr); 2983 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2984 trunc_page(ph->p_vaddr); 2985 prot = before ? (PROT_READ | PROT_WRITE) : 2986 convert_prot(ph->p_flags); 2987 if (mprotect(base, sz, prot) == -1) { 2988 _rtld_error("%s: Cannot write-%sable text segment: %s", 2989 obj->path, before ? "en" : "dis", 2990 rtld_strerror(errno)); 2991 return (-1); 2992 } 2993 } 2994 return (0); 2995 } 2996 2997 /* 2998 * Relocate single object. 2999 * Returns 0 on success, or -1 on failure. 3000 */ 3001 static int 3002 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3003 int flags, RtldLockState *lockstate) 3004 { 3005 3006 if (obj->relocated) 3007 return (0); 3008 obj->relocated = true; 3009 if (obj != rtldobj) 3010 dbg("relocating \"%s\"", obj->path); 3011 3012 if (obj->symtab == NULL || obj->strtab == NULL || 3013 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3014 dbg("object %s has no run-time symbol table", obj->path); 3015 3016 /* There are relocations to the write-protected text segment. */ 3017 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3018 return (-1); 3019 3020 /* Process the non-PLT non-IFUNC relocations. */ 3021 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3022 return (-1); 3023 3024 /* Re-protected the text segment. */ 3025 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3026 return (-1); 3027 3028 /* Set the special PLT or GOT entries. */ 3029 init_pltgot(obj); 3030 3031 /* Process the PLT relocations. */ 3032 if (reloc_plt(obj, flags, lockstate) == -1) 3033 return (-1); 3034 /* Relocate the jump slots if we are doing immediate binding. */ 3035 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3036 lockstate) == -1) 3037 return (-1); 3038 3039 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3040 return (-1); 3041 3042 /* 3043 * Set up the magic number and version in the Obj_Entry. These 3044 * were checked in the crt1.o from the original ElfKit, so we 3045 * set them for backward compatibility. 3046 */ 3047 obj->magic = RTLD_MAGIC; 3048 obj->version = RTLD_VERSION; 3049 3050 return (0); 3051 } 3052 3053 /* 3054 * Relocate newly-loaded shared objects. The argument is a pointer to 3055 * the Obj_Entry for the first such object. All objects from the first 3056 * to the end of the list of objects are relocated. Returns 0 on success, 3057 * or -1 on failure. 3058 */ 3059 static int 3060 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3061 int flags, RtldLockState *lockstate) 3062 { 3063 Obj_Entry *obj; 3064 int error; 3065 3066 for (error = 0, obj = first; obj != NULL; 3067 obj = TAILQ_NEXT(obj, next)) { 3068 if (obj->marker) 3069 continue; 3070 error = relocate_object(obj, bind_now, rtldobj, flags, 3071 lockstate); 3072 if (error == -1) 3073 break; 3074 } 3075 return (error); 3076 } 3077 3078 /* 3079 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3080 * referencing STT_GNU_IFUNC symbols is postponed till the other 3081 * relocations are done. The indirect functions specified as 3082 * ifunc are allowed to call other symbols, so we need to have 3083 * objects relocated before asking for resolution from indirects. 3084 * 3085 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3086 * instead of the usual lazy handling of PLT slots. It is 3087 * consistent with how GNU does it. 3088 */ 3089 static int 3090 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3091 RtldLockState *lockstate) 3092 { 3093 3094 if (obj->ifuncs_resolved) 3095 return (0); 3096 obj->ifuncs_resolved = true; 3097 if (!obj->irelative && !obj->irelative_nonplt && 3098 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3099 !obj->non_plt_gnu_ifunc) 3100 return (0); 3101 if (obj_disable_relro(obj) == -1 || 3102 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3103 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3104 lockstate) == -1) || 3105 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3106 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3107 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3108 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3109 obj_enforce_relro(obj) == -1) 3110 return (-1); 3111 return (0); 3112 } 3113 3114 static int 3115 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3116 RtldLockState *lockstate) 3117 { 3118 Objlist_Entry *elm; 3119 Obj_Entry *obj; 3120 3121 STAILQ_FOREACH(elm, list, link) { 3122 obj = elm->obj; 3123 if (obj->marker) 3124 continue; 3125 if (resolve_object_ifunc(obj, bind_now, flags, 3126 lockstate) == -1) 3127 return (-1); 3128 } 3129 return (0); 3130 } 3131 3132 /* 3133 * Cleanup procedure. It will be called (by the atexit mechanism) just 3134 * before the process exits. 3135 */ 3136 static void 3137 rtld_exit(void) 3138 { 3139 RtldLockState lockstate; 3140 3141 wlock_acquire(rtld_bind_lock, &lockstate); 3142 dbg("rtld_exit()"); 3143 objlist_call_fini(&list_fini, NULL, &lockstate); 3144 /* No need to remove the items from the list, since we are exiting. */ 3145 if (!libmap_disable) 3146 lm_fini(); 3147 lock_release(rtld_bind_lock, &lockstate); 3148 } 3149 3150 static void 3151 rtld_nop_exit(void) 3152 { 3153 } 3154 3155 /* 3156 * Iterate over a search path, translate each element, and invoke the 3157 * callback on the result. 3158 */ 3159 static void * 3160 path_enumerate(const char *path, path_enum_proc callback, 3161 const char *refobj_path, void *arg) 3162 { 3163 const char *trans; 3164 if (path == NULL) 3165 return (NULL); 3166 3167 path += strspn(path, ":;"); 3168 while (*path != '\0') { 3169 size_t len; 3170 char *res; 3171 3172 len = strcspn(path, ":;"); 3173 trans = lm_findn(refobj_path, path, len); 3174 if (trans) 3175 res = callback(trans, strlen(trans), arg); 3176 else 3177 res = callback(path, len, arg); 3178 3179 if (res != NULL) 3180 return (res); 3181 3182 path += len; 3183 path += strspn(path, ":;"); 3184 } 3185 3186 return (NULL); 3187 } 3188 3189 struct try_library_args { 3190 const char *name; 3191 size_t namelen; 3192 char *buffer; 3193 size_t buflen; 3194 int fd; 3195 }; 3196 3197 static void * 3198 try_library_path(const char *dir, size_t dirlen, void *param) 3199 { 3200 struct try_library_args *arg; 3201 int fd; 3202 3203 arg = param; 3204 if (*dir == '/' || trust) { 3205 char *pathname; 3206 3207 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3208 return (NULL); 3209 3210 pathname = arg->buffer; 3211 strncpy(pathname, dir, dirlen); 3212 pathname[dirlen] = '/'; 3213 strcpy(pathname + dirlen + 1, arg->name); 3214 3215 dbg(" Trying \"%s\"", pathname); 3216 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3217 if (fd >= 0) { 3218 dbg(" Opened \"%s\", fd %d", pathname, fd); 3219 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3220 strcpy(pathname, arg->buffer); 3221 arg->fd = fd; 3222 return (pathname); 3223 } else { 3224 dbg(" Failed to open \"%s\": %s", 3225 pathname, rtld_strerror(errno)); 3226 } 3227 } 3228 return (NULL); 3229 } 3230 3231 static char * 3232 search_library_path(const char *name, const char *path, 3233 const char *refobj_path, int *fdp) 3234 { 3235 char *p; 3236 struct try_library_args arg; 3237 3238 if (path == NULL) 3239 return NULL; 3240 3241 arg.name = name; 3242 arg.namelen = strlen(name); 3243 arg.buffer = xmalloc(PATH_MAX); 3244 arg.buflen = PATH_MAX; 3245 arg.fd = -1; 3246 3247 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3248 *fdp = arg.fd; 3249 3250 free(arg.buffer); 3251 3252 return (p); 3253 } 3254 3255 3256 /* 3257 * Finds the library with the given name using the directory descriptors 3258 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3259 * 3260 * Returns a freshly-opened close-on-exec file descriptor for the library, 3261 * or -1 if the library cannot be found. 3262 */ 3263 static char * 3264 search_library_pathfds(const char *name, const char *path, int *fdp) 3265 { 3266 char *envcopy, *fdstr, *found, *last_token; 3267 size_t len; 3268 int dirfd, fd; 3269 3270 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3271 3272 /* Don't load from user-specified libdirs into setuid binaries. */ 3273 if (!trust) 3274 return (NULL); 3275 3276 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3277 if (path == NULL) 3278 return (NULL); 3279 3280 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3281 if (name[0] == '/') { 3282 dbg("Absolute path (%s) passed to %s", name, __func__); 3283 return (NULL); 3284 } 3285 3286 /* 3287 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3288 * copy of the path, as strtok_r rewrites separator tokens 3289 * with '\0'. 3290 */ 3291 found = NULL; 3292 envcopy = xstrdup(path); 3293 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3294 fdstr = strtok_r(NULL, ":", &last_token)) { 3295 dirfd = parse_integer(fdstr); 3296 if (dirfd < 0) { 3297 _rtld_error("failed to parse directory FD: '%s'", 3298 fdstr); 3299 break; 3300 } 3301 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3302 if (fd >= 0) { 3303 *fdp = fd; 3304 len = strlen(fdstr) + strlen(name) + 3; 3305 found = xmalloc(len); 3306 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3307 _rtld_error("error generating '%d/%s'", 3308 dirfd, name); 3309 rtld_die(); 3310 } 3311 dbg("open('%s') => %d", found, fd); 3312 break; 3313 } 3314 } 3315 free(envcopy); 3316 3317 return (found); 3318 } 3319 3320 3321 int 3322 dlclose(void *handle) 3323 { 3324 RtldLockState lockstate; 3325 int error; 3326 3327 wlock_acquire(rtld_bind_lock, &lockstate); 3328 error = dlclose_locked(handle, &lockstate); 3329 lock_release(rtld_bind_lock, &lockstate); 3330 return (error); 3331 } 3332 3333 static int 3334 dlclose_locked(void *handle, RtldLockState *lockstate) 3335 { 3336 Obj_Entry *root; 3337 3338 root = dlcheck(handle); 3339 if (root == NULL) 3340 return -1; 3341 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3342 root->path); 3343 3344 /* Unreference the object and its dependencies. */ 3345 root->dl_refcount--; 3346 3347 if (root->refcount == 1) { 3348 /* 3349 * The object will be no longer referenced, so we must unload it. 3350 * First, call the fini functions. 3351 */ 3352 objlist_call_fini(&list_fini, root, lockstate); 3353 3354 unref_dag(root); 3355 3356 /* Finish cleaning up the newly-unreferenced objects. */ 3357 GDB_STATE(RT_DELETE,&root->linkmap); 3358 unload_object(root, lockstate); 3359 GDB_STATE(RT_CONSISTENT,NULL); 3360 } else 3361 unref_dag(root); 3362 3363 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3364 return 0; 3365 } 3366 3367 char * 3368 dlerror(void) 3369 { 3370 char *msg = error_message; 3371 error_message = NULL; 3372 return msg; 3373 } 3374 3375 /* 3376 * This function is deprecated and has no effect. 3377 */ 3378 void 3379 dllockinit(void *context, 3380 void *(*_lock_create)(void *context) __unused, 3381 void (*_rlock_acquire)(void *lock) __unused, 3382 void (*_wlock_acquire)(void *lock) __unused, 3383 void (*_lock_release)(void *lock) __unused, 3384 void (*_lock_destroy)(void *lock) __unused, 3385 void (*context_destroy)(void *context)) 3386 { 3387 static void *cur_context; 3388 static void (*cur_context_destroy)(void *); 3389 3390 /* Just destroy the context from the previous call, if necessary. */ 3391 if (cur_context_destroy != NULL) 3392 cur_context_destroy(cur_context); 3393 cur_context = context; 3394 cur_context_destroy = context_destroy; 3395 } 3396 3397 void * 3398 dlopen(const char *name, int mode) 3399 { 3400 3401 return (rtld_dlopen(name, -1, mode)); 3402 } 3403 3404 void * 3405 fdlopen(int fd, int mode) 3406 { 3407 3408 return (rtld_dlopen(NULL, fd, mode)); 3409 } 3410 3411 static void * 3412 rtld_dlopen(const char *name, int fd, int mode) 3413 { 3414 RtldLockState lockstate; 3415 int lo_flags; 3416 3417 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3418 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3419 if (ld_tracing != NULL) { 3420 rlock_acquire(rtld_bind_lock, &lockstate); 3421 if (sigsetjmp(lockstate.env, 0) != 0) 3422 lock_upgrade(rtld_bind_lock, &lockstate); 3423 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3424 lock_release(rtld_bind_lock, &lockstate); 3425 } 3426 lo_flags = RTLD_LO_DLOPEN; 3427 if (mode & RTLD_NODELETE) 3428 lo_flags |= RTLD_LO_NODELETE; 3429 if (mode & RTLD_NOLOAD) 3430 lo_flags |= RTLD_LO_NOLOAD; 3431 if (mode & RTLD_DEEPBIND) 3432 lo_flags |= RTLD_LO_DEEPBIND; 3433 if (ld_tracing != NULL) 3434 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3435 3436 return (dlopen_object(name, fd, obj_main, lo_flags, 3437 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3438 } 3439 3440 static void 3441 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3442 { 3443 3444 obj->dl_refcount--; 3445 unref_dag(obj); 3446 if (obj->refcount == 0) 3447 unload_object(obj, lockstate); 3448 } 3449 3450 static Obj_Entry * 3451 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3452 int mode, RtldLockState *lockstate) 3453 { 3454 Obj_Entry *old_obj_tail; 3455 Obj_Entry *obj; 3456 Objlist initlist; 3457 RtldLockState mlockstate; 3458 int result; 3459 3460 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3461 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3462 refobj->path, lo_flags, mode); 3463 objlist_init(&initlist); 3464 3465 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3466 wlock_acquire(rtld_bind_lock, &mlockstate); 3467 lockstate = &mlockstate; 3468 } 3469 GDB_STATE(RT_ADD,NULL); 3470 3471 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3472 obj = NULL; 3473 if (name == NULL && fd == -1) { 3474 obj = obj_main; 3475 obj->refcount++; 3476 } else { 3477 obj = load_object(name, fd, refobj, lo_flags); 3478 } 3479 3480 if (obj) { 3481 obj->dl_refcount++; 3482 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3483 objlist_push_tail(&list_global, obj); 3484 if (globallist_next(old_obj_tail) != NULL) { 3485 /* We loaded something new. */ 3486 assert(globallist_next(old_obj_tail) == obj); 3487 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3488 obj->symbolic = true; 3489 result = 0; 3490 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3491 obj->static_tls && !allocate_tls_offset(obj)) { 3492 _rtld_error("%s: No space available " 3493 "for static Thread Local Storage", obj->path); 3494 result = -1; 3495 } 3496 if (result != -1) 3497 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3498 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3499 init_dag(obj); 3500 ref_dag(obj); 3501 if (result != -1) 3502 result = rtld_verify_versions(&obj->dagmembers); 3503 if (result != -1 && ld_tracing) 3504 goto trace; 3505 if (result == -1 || relocate_object_dag(obj, 3506 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3507 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3508 lockstate) == -1) { 3509 dlopen_cleanup(obj, lockstate); 3510 obj = NULL; 3511 } else if (lo_flags & RTLD_LO_EARLY) { 3512 /* 3513 * Do not call the init functions for early loaded 3514 * filtees. The image is still not initialized enough 3515 * for them to work. 3516 * 3517 * Our object is found by the global object list and 3518 * will be ordered among all init calls done right 3519 * before transferring control to main. 3520 */ 3521 } else { 3522 /* Make list of init functions to call. */ 3523 initlist_add_objects(obj, obj, &initlist); 3524 } 3525 /* 3526 * Process all no_delete or global objects here, given 3527 * them own DAGs to prevent their dependencies from being 3528 * unloaded. This has to be done after we have loaded all 3529 * of the dependencies, so that we do not miss any. 3530 */ 3531 if (obj != NULL) 3532 process_z(obj); 3533 } else { 3534 /* 3535 * Bump the reference counts for objects on this DAG. If 3536 * this is the first dlopen() call for the object that was 3537 * already loaded as a dependency, initialize the dag 3538 * starting at it. 3539 */ 3540 init_dag(obj); 3541 ref_dag(obj); 3542 3543 if ((lo_flags & RTLD_LO_TRACE) != 0) 3544 goto trace; 3545 } 3546 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3547 obj->z_nodelete) && !obj->ref_nodel) { 3548 dbg("obj %s nodelete", obj->path); 3549 ref_dag(obj); 3550 obj->z_nodelete = obj->ref_nodel = true; 3551 } 3552 } 3553 3554 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3555 name); 3556 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3557 3558 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3559 map_stacks_exec(lockstate); 3560 if (obj != NULL) 3561 distribute_static_tls(&initlist, lockstate); 3562 } 3563 3564 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3565 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3566 lockstate) == -1) { 3567 objlist_clear(&initlist); 3568 dlopen_cleanup(obj, lockstate); 3569 if (lockstate == &mlockstate) 3570 lock_release(rtld_bind_lock, lockstate); 3571 return (NULL); 3572 } 3573 3574 if (!(lo_flags & RTLD_LO_EARLY)) { 3575 /* Call the init functions. */ 3576 objlist_call_init(&initlist, lockstate); 3577 } 3578 objlist_clear(&initlist); 3579 if (lockstate == &mlockstate) 3580 lock_release(rtld_bind_lock, lockstate); 3581 return obj; 3582 trace: 3583 trace_loaded_objects(obj); 3584 if (lockstate == &mlockstate) 3585 lock_release(rtld_bind_lock, lockstate); 3586 exit(0); 3587 } 3588 3589 static void * 3590 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3591 int flags) 3592 { 3593 DoneList donelist; 3594 const Obj_Entry *obj, *defobj; 3595 const Elf_Sym *def; 3596 SymLook req; 3597 RtldLockState lockstate; 3598 tls_index ti; 3599 void *sym; 3600 int res; 3601 3602 def = NULL; 3603 defobj = NULL; 3604 symlook_init(&req, name); 3605 req.ventry = ve; 3606 req.flags = flags | SYMLOOK_IN_PLT; 3607 req.lockstate = &lockstate; 3608 3609 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3610 rlock_acquire(rtld_bind_lock, &lockstate); 3611 if (sigsetjmp(lockstate.env, 0) != 0) 3612 lock_upgrade(rtld_bind_lock, &lockstate); 3613 if (handle == NULL || handle == RTLD_NEXT || 3614 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3615 3616 if ((obj = obj_from_addr(retaddr)) == NULL) { 3617 _rtld_error("Cannot determine caller's shared object"); 3618 lock_release(rtld_bind_lock, &lockstate); 3619 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3620 return NULL; 3621 } 3622 if (handle == NULL) { /* Just the caller's shared object. */ 3623 res = symlook_obj(&req, obj); 3624 if (res == 0) { 3625 def = req.sym_out; 3626 defobj = req.defobj_out; 3627 } 3628 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3629 handle == RTLD_SELF) { /* ... caller included */ 3630 if (handle == RTLD_NEXT) 3631 obj = globallist_next(obj); 3632 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3633 if (obj->marker) 3634 continue; 3635 res = symlook_obj(&req, obj); 3636 if (res == 0) { 3637 if (def == NULL || 3638 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3639 def = req.sym_out; 3640 defobj = req.defobj_out; 3641 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3642 break; 3643 } 3644 } 3645 } 3646 /* 3647 * Search the dynamic linker itself, and possibly resolve the 3648 * symbol from there. This is how the application links to 3649 * dynamic linker services such as dlopen. 3650 */ 3651 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3652 res = symlook_obj(&req, &obj_rtld); 3653 if (res == 0) { 3654 def = req.sym_out; 3655 defobj = req.defobj_out; 3656 } 3657 } 3658 } else { 3659 assert(handle == RTLD_DEFAULT); 3660 res = symlook_default(&req, obj); 3661 if (res == 0) { 3662 defobj = req.defobj_out; 3663 def = req.sym_out; 3664 } 3665 } 3666 } else { 3667 if ((obj = dlcheck(handle)) == NULL) { 3668 lock_release(rtld_bind_lock, &lockstate); 3669 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3670 return NULL; 3671 } 3672 3673 donelist_init(&donelist); 3674 if (obj->mainprog) { 3675 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3676 res = symlook_global(&req, &donelist); 3677 if (res == 0) { 3678 def = req.sym_out; 3679 defobj = req.defobj_out; 3680 } 3681 /* 3682 * Search the dynamic linker itself, and possibly resolve the 3683 * symbol from there. This is how the application links to 3684 * dynamic linker services such as dlopen. 3685 */ 3686 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3687 res = symlook_obj(&req, &obj_rtld); 3688 if (res == 0) { 3689 def = req.sym_out; 3690 defobj = req.defobj_out; 3691 } 3692 } 3693 } 3694 else { 3695 /* Search the whole DAG rooted at the given object. */ 3696 res = symlook_list(&req, &obj->dagmembers, &donelist); 3697 if (res == 0) { 3698 def = req.sym_out; 3699 defobj = req.defobj_out; 3700 } 3701 } 3702 } 3703 3704 if (def != NULL) { 3705 lock_release(rtld_bind_lock, &lockstate); 3706 3707 /* 3708 * The value required by the caller is derived from the value 3709 * of the symbol. this is simply the relocated value of the 3710 * symbol. 3711 */ 3712 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3713 sym = make_function_pointer(def, defobj); 3714 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3715 sym = rtld_resolve_ifunc(defobj, def); 3716 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3717 ti.ti_module = defobj->tlsindex; 3718 ti.ti_offset = def->st_value; 3719 sym = __tls_get_addr(&ti); 3720 } else 3721 sym = defobj->relocbase + def->st_value; 3722 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3723 return (sym); 3724 } 3725 3726 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3727 ve != NULL ? ve->name : ""); 3728 lock_release(rtld_bind_lock, &lockstate); 3729 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3730 return NULL; 3731 } 3732 3733 void * 3734 dlsym(void *handle, const char *name) 3735 { 3736 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3737 SYMLOOK_DLSYM); 3738 } 3739 3740 dlfunc_t 3741 dlfunc(void *handle, const char *name) 3742 { 3743 union { 3744 void *d; 3745 dlfunc_t f; 3746 } rv; 3747 3748 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3749 SYMLOOK_DLSYM); 3750 return (rv.f); 3751 } 3752 3753 void * 3754 dlvsym(void *handle, const char *name, const char *version) 3755 { 3756 Ver_Entry ventry; 3757 3758 ventry.name = version; 3759 ventry.file = NULL; 3760 ventry.hash = elf_hash(version); 3761 ventry.flags= 0; 3762 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3763 SYMLOOK_DLSYM); 3764 } 3765 3766 int 3767 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3768 { 3769 const Obj_Entry *obj; 3770 RtldLockState lockstate; 3771 3772 rlock_acquire(rtld_bind_lock, &lockstate); 3773 obj = obj_from_addr(addr); 3774 if (obj == NULL) { 3775 _rtld_error("No shared object contains address"); 3776 lock_release(rtld_bind_lock, &lockstate); 3777 return (0); 3778 } 3779 rtld_fill_dl_phdr_info(obj, phdr_info); 3780 lock_release(rtld_bind_lock, &lockstate); 3781 return (1); 3782 } 3783 3784 int 3785 dladdr(const void *addr, Dl_info *info) 3786 { 3787 const Obj_Entry *obj; 3788 const Elf_Sym *def; 3789 void *symbol_addr; 3790 unsigned long symoffset; 3791 RtldLockState lockstate; 3792 3793 rlock_acquire(rtld_bind_lock, &lockstate); 3794 obj = obj_from_addr(addr); 3795 if (obj == NULL) { 3796 _rtld_error("No shared object contains address"); 3797 lock_release(rtld_bind_lock, &lockstate); 3798 return 0; 3799 } 3800 info->dli_fname = obj->path; 3801 info->dli_fbase = obj->mapbase; 3802 info->dli_saddr = (void *)0; 3803 info->dli_sname = NULL; 3804 3805 /* 3806 * Walk the symbol list looking for the symbol whose address is 3807 * closest to the address sent in. 3808 */ 3809 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3810 def = obj->symtab + symoffset; 3811 3812 /* 3813 * For skip the symbol if st_shndx is either SHN_UNDEF or 3814 * SHN_COMMON. 3815 */ 3816 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3817 continue; 3818 3819 /* 3820 * If the symbol is greater than the specified address, or if it 3821 * is further away from addr than the current nearest symbol, 3822 * then reject it. 3823 */ 3824 symbol_addr = obj->relocbase + def->st_value; 3825 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3826 continue; 3827 3828 /* Update our idea of the nearest symbol. */ 3829 info->dli_sname = obj->strtab + def->st_name; 3830 info->dli_saddr = symbol_addr; 3831 3832 /* Exact match? */ 3833 if (info->dli_saddr == addr) 3834 break; 3835 } 3836 lock_release(rtld_bind_lock, &lockstate); 3837 return 1; 3838 } 3839 3840 int 3841 dlinfo(void *handle, int request, void *p) 3842 { 3843 const Obj_Entry *obj; 3844 RtldLockState lockstate; 3845 int error; 3846 3847 rlock_acquire(rtld_bind_lock, &lockstate); 3848 3849 if (handle == NULL || handle == RTLD_SELF) { 3850 void *retaddr; 3851 3852 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3853 if ((obj = obj_from_addr(retaddr)) == NULL) 3854 _rtld_error("Cannot determine caller's shared object"); 3855 } else 3856 obj = dlcheck(handle); 3857 3858 if (obj == NULL) { 3859 lock_release(rtld_bind_lock, &lockstate); 3860 return (-1); 3861 } 3862 3863 error = 0; 3864 switch (request) { 3865 case RTLD_DI_LINKMAP: 3866 *((struct link_map const **)p) = &obj->linkmap; 3867 break; 3868 case RTLD_DI_ORIGIN: 3869 error = rtld_dirname(obj->path, p); 3870 break; 3871 3872 case RTLD_DI_SERINFOSIZE: 3873 case RTLD_DI_SERINFO: 3874 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3875 break; 3876 3877 default: 3878 _rtld_error("Invalid request %d passed to dlinfo()", request); 3879 error = -1; 3880 } 3881 3882 lock_release(rtld_bind_lock, &lockstate); 3883 3884 return (error); 3885 } 3886 3887 static void 3888 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3889 { 3890 3891 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3892 phdr_info->dlpi_name = obj->path; 3893 phdr_info->dlpi_phdr = obj->phdr; 3894 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3895 phdr_info->dlpi_tls_modid = obj->tlsindex; 3896 phdr_info->dlpi_tls_data = obj->tlsinit; 3897 phdr_info->dlpi_adds = obj_loads; 3898 phdr_info->dlpi_subs = obj_loads - obj_count; 3899 } 3900 3901 int 3902 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3903 { 3904 struct dl_phdr_info phdr_info; 3905 Obj_Entry *obj, marker; 3906 RtldLockState bind_lockstate, phdr_lockstate; 3907 int error; 3908 3909 init_marker(&marker); 3910 error = 0; 3911 3912 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3913 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3914 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3915 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3916 rtld_fill_dl_phdr_info(obj, &phdr_info); 3917 hold_object(obj); 3918 lock_release(rtld_bind_lock, &bind_lockstate); 3919 3920 error = callback(&phdr_info, sizeof phdr_info, param); 3921 3922 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3923 unhold_object(obj); 3924 obj = globallist_next(&marker); 3925 TAILQ_REMOVE(&obj_list, &marker, next); 3926 if (error != 0) { 3927 lock_release(rtld_bind_lock, &bind_lockstate); 3928 lock_release(rtld_phdr_lock, &phdr_lockstate); 3929 return (error); 3930 } 3931 } 3932 3933 if (error == 0) { 3934 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3935 lock_release(rtld_bind_lock, &bind_lockstate); 3936 error = callback(&phdr_info, sizeof(phdr_info), param); 3937 } 3938 lock_release(rtld_phdr_lock, &phdr_lockstate); 3939 return (error); 3940 } 3941 3942 static void * 3943 fill_search_info(const char *dir, size_t dirlen, void *param) 3944 { 3945 struct fill_search_info_args *arg; 3946 3947 arg = param; 3948 3949 if (arg->request == RTLD_DI_SERINFOSIZE) { 3950 arg->serinfo->dls_cnt ++; 3951 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3952 } else { 3953 struct dl_serpath *s_entry; 3954 3955 s_entry = arg->serpath; 3956 s_entry->dls_name = arg->strspace; 3957 s_entry->dls_flags = arg->flags; 3958 3959 strncpy(arg->strspace, dir, dirlen); 3960 arg->strspace[dirlen] = '\0'; 3961 3962 arg->strspace += dirlen + 1; 3963 arg->serpath++; 3964 } 3965 3966 return (NULL); 3967 } 3968 3969 static int 3970 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3971 { 3972 struct dl_serinfo _info; 3973 struct fill_search_info_args args; 3974 3975 args.request = RTLD_DI_SERINFOSIZE; 3976 args.serinfo = &_info; 3977 3978 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3979 _info.dls_cnt = 0; 3980 3981 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3982 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3983 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3984 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3985 if (!obj->z_nodeflib) 3986 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3987 3988 3989 if (request == RTLD_DI_SERINFOSIZE) { 3990 info->dls_size = _info.dls_size; 3991 info->dls_cnt = _info.dls_cnt; 3992 return (0); 3993 } 3994 3995 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3996 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3997 return (-1); 3998 } 3999 4000 args.request = RTLD_DI_SERINFO; 4001 args.serinfo = info; 4002 args.serpath = &info->dls_serpath[0]; 4003 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4004 4005 args.flags = LA_SER_RUNPATH; 4006 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4007 return (-1); 4008 4009 args.flags = LA_SER_LIBPATH; 4010 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4011 return (-1); 4012 4013 args.flags = LA_SER_RUNPATH; 4014 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4015 return (-1); 4016 4017 args.flags = LA_SER_CONFIG; 4018 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4019 != NULL) 4020 return (-1); 4021 4022 args.flags = LA_SER_DEFAULT; 4023 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4024 fill_search_info, NULL, &args) != NULL) 4025 return (-1); 4026 return (0); 4027 } 4028 4029 static int 4030 rtld_dirname(const char *path, char *bname) 4031 { 4032 const char *endp; 4033 4034 /* Empty or NULL string gets treated as "." */ 4035 if (path == NULL || *path == '\0') { 4036 bname[0] = '.'; 4037 bname[1] = '\0'; 4038 return (0); 4039 } 4040 4041 /* Strip trailing slashes */ 4042 endp = path + strlen(path) - 1; 4043 while (endp > path && *endp == '/') 4044 endp--; 4045 4046 /* Find the start of the dir */ 4047 while (endp > path && *endp != '/') 4048 endp--; 4049 4050 /* Either the dir is "/" or there are no slashes */ 4051 if (endp == path) { 4052 bname[0] = *endp == '/' ? '/' : '.'; 4053 bname[1] = '\0'; 4054 return (0); 4055 } else { 4056 do { 4057 endp--; 4058 } while (endp > path && *endp == '/'); 4059 } 4060 4061 if (endp - path + 2 > PATH_MAX) 4062 { 4063 _rtld_error("Filename is too long: %s", path); 4064 return(-1); 4065 } 4066 4067 strncpy(bname, path, endp - path + 1); 4068 bname[endp - path + 1] = '\0'; 4069 return (0); 4070 } 4071 4072 static int 4073 rtld_dirname_abs(const char *path, char *base) 4074 { 4075 char *last; 4076 4077 if (realpath(path, base) == NULL) { 4078 _rtld_error("realpath \"%s\" failed (%s)", path, 4079 rtld_strerror(errno)); 4080 return (-1); 4081 } 4082 dbg("%s -> %s", path, base); 4083 last = strrchr(base, '/'); 4084 if (last == NULL) { 4085 _rtld_error("non-abs result from realpath \"%s\"", path); 4086 return (-1); 4087 } 4088 if (last != base) 4089 *last = '\0'; 4090 return (0); 4091 } 4092 4093 static void 4094 linkmap_add(Obj_Entry *obj) 4095 { 4096 struct link_map *l, *prev; 4097 4098 l = &obj->linkmap; 4099 l->l_name = obj->path; 4100 l->l_base = obj->mapbase; 4101 l->l_ld = obj->dynamic; 4102 l->l_addr = obj->relocbase; 4103 4104 if (r_debug.r_map == NULL) { 4105 r_debug.r_map = l; 4106 return; 4107 } 4108 4109 /* 4110 * Scan to the end of the list, but not past the entry for the 4111 * dynamic linker, which we want to keep at the very end. 4112 */ 4113 for (prev = r_debug.r_map; 4114 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4115 prev = prev->l_next) 4116 ; 4117 4118 /* Link in the new entry. */ 4119 l->l_prev = prev; 4120 l->l_next = prev->l_next; 4121 if (l->l_next != NULL) 4122 l->l_next->l_prev = l; 4123 prev->l_next = l; 4124 } 4125 4126 static void 4127 linkmap_delete(Obj_Entry *obj) 4128 { 4129 struct link_map *l; 4130 4131 l = &obj->linkmap; 4132 if (l->l_prev == NULL) { 4133 if ((r_debug.r_map = l->l_next) != NULL) 4134 l->l_next->l_prev = NULL; 4135 return; 4136 } 4137 4138 if ((l->l_prev->l_next = l->l_next) != NULL) 4139 l->l_next->l_prev = l->l_prev; 4140 } 4141 4142 /* 4143 * Function for the debugger to set a breakpoint on to gain control. 4144 * 4145 * The two parameters allow the debugger to easily find and determine 4146 * what the runtime loader is doing and to whom it is doing it. 4147 * 4148 * When the loadhook trap is hit (r_debug_state, set at program 4149 * initialization), the arguments can be found on the stack: 4150 * 4151 * +8 struct link_map *m 4152 * +4 struct r_debug *rd 4153 * +0 RetAddr 4154 */ 4155 void 4156 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4157 { 4158 /* 4159 * The following is a hack to force the compiler to emit calls to 4160 * this function, even when optimizing. If the function is empty, 4161 * the compiler is not obliged to emit any code for calls to it, 4162 * even when marked __noinline. However, gdb depends on those 4163 * calls being made. 4164 */ 4165 __compiler_membar(); 4166 } 4167 4168 /* 4169 * A function called after init routines have completed. This can be used to 4170 * break before a program's entry routine is called, and can be used when 4171 * main is not available in the symbol table. 4172 */ 4173 void 4174 _r_debug_postinit(struct link_map *m __unused) 4175 { 4176 4177 /* See r_debug_state(). */ 4178 __compiler_membar(); 4179 } 4180 4181 static void 4182 release_object(Obj_Entry *obj) 4183 { 4184 4185 if (obj->holdcount > 0) { 4186 obj->unholdfree = true; 4187 return; 4188 } 4189 munmap(obj->mapbase, obj->mapsize); 4190 linkmap_delete(obj); 4191 obj_free(obj); 4192 } 4193 4194 /* 4195 * Get address of the pointer variable in the main program. 4196 * Prefer non-weak symbol over the weak one. 4197 */ 4198 static const void ** 4199 get_program_var_addr(const char *name, RtldLockState *lockstate) 4200 { 4201 SymLook req; 4202 DoneList donelist; 4203 4204 symlook_init(&req, name); 4205 req.lockstate = lockstate; 4206 donelist_init(&donelist); 4207 if (symlook_global(&req, &donelist) != 0) 4208 return (NULL); 4209 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4210 return ((const void **)make_function_pointer(req.sym_out, 4211 req.defobj_out)); 4212 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4213 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4214 else 4215 return ((const void **)(req.defobj_out->relocbase + 4216 req.sym_out->st_value)); 4217 } 4218 4219 /* 4220 * Set a pointer variable in the main program to the given value. This 4221 * is used to set key variables such as "environ" before any of the 4222 * init functions are called. 4223 */ 4224 static void 4225 set_program_var(const char *name, const void *value) 4226 { 4227 const void **addr; 4228 4229 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4230 dbg("\"%s\": *%p <-- %p", name, addr, value); 4231 *addr = value; 4232 } 4233 } 4234 4235 /* 4236 * Search the global objects, including dependencies and main object, 4237 * for the given symbol. 4238 */ 4239 static int 4240 symlook_global(SymLook *req, DoneList *donelist) 4241 { 4242 SymLook req1; 4243 const Objlist_Entry *elm; 4244 int res; 4245 4246 symlook_init_from_req(&req1, req); 4247 4248 /* Search all objects loaded at program start up. */ 4249 if (req->defobj_out == NULL || 4250 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4251 res = symlook_list(&req1, &list_main, donelist); 4252 if (res == 0 && (req->defobj_out == NULL || 4253 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4254 req->sym_out = req1.sym_out; 4255 req->defobj_out = req1.defobj_out; 4256 assert(req->defobj_out != NULL); 4257 } 4258 } 4259 4260 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4261 STAILQ_FOREACH(elm, &list_global, link) { 4262 if (req->defobj_out != NULL && 4263 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4264 break; 4265 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4266 if (res == 0 && (req->defobj_out == NULL || 4267 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4268 req->sym_out = req1.sym_out; 4269 req->defobj_out = req1.defobj_out; 4270 assert(req->defobj_out != NULL); 4271 } 4272 } 4273 4274 return (req->sym_out != NULL ? 0 : ESRCH); 4275 } 4276 4277 /* 4278 * Given a symbol name in a referencing object, find the corresponding 4279 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4280 * no definition was found. Returns a pointer to the Obj_Entry of the 4281 * defining object via the reference parameter DEFOBJ_OUT. 4282 */ 4283 static int 4284 symlook_default(SymLook *req, const Obj_Entry *refobj) 4285 { 4286 DoneList donelist; 4287 const Objlist_Entry *elm; 4288 SymLook req1; 4289 int res; 4290 4291 donelist_init(&donelist); 4292 symlook_init_from_req(&req1, req); 4293 4294 /* 4295 * Look first in the referencing object if linked symbolically, 4296 * and similarly handle protected symbols. 4297 */ 4298 res = symlook_obj(&req1, refobj); 4299 if (res == 0 && (refobj->symbolic || 4300 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4301 req->sym_out = req1.sym_out; 4302 req->defobj_out = req1.defobj_out; 4303 assert(req->defobj_out != NULL); 4304 } 4305 if (refobj->symbolic || req->defobj_out != NULL) 4306 donelist_check(&donelist, refobj); 4307 4308 symlook_global(req, &donelist); 4309 4310 /* Search all dlopened DAGs containing the referencing object. */ 4311 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4312 if (req->sym_out != NULL && 4313 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4314 break; 4315 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4316 if (res == 0 && (req->sym_out == NULL || 4317 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4318 req->sym_out = req1.sym_out; 4319 req->defobj_out = req1.defobj_out; 4320 assert(req->defobj_out != NULL); 4321 } 4322 } 4323 4324 /* 4325 * Search the dynamic linker itself, and possibly resolve the 4326 * symbol from there. This is how the application links to 4327 * dynamic linker services such as dlopen. 4328 */ 4329 if (req->sym_out == NULL || 4330 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4331 res = symlook_obj(&req1, &obj_rtld); 4332 if (res == 0) { 4333 req->sym_out = req1.sym_out; 4334 req->defobj_out = req1.defobj_out; 4335 assert(req->defobj_out != NULL); 4336 } 4337 } 4338 4339 return (req->sym_out != NULL ? 0 : ESRCH); 4340 } 4341 4342 static int 4343 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4344 { 4345 const Elf_Sym *def; 4346 const Obj_Entry *defobj; 4347 const Objlist_Entry *elm; 4348 SymLook req1; 4349 int res; 4350 4351 def = NULL; 4352 defobj = NULL; 4353 STAILQ_FOREACH(elm, objlist, link) { 4354 if (donelist_check(dlp, elm->obj)) 4355 continue; 4356 symlook_init_from_req(&req1, req); 4357 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4358 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4359 def = req1.sym_out; 4360 defobj = req1.defobj_out; 4361 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4362 break; 4363 } 4364 } 4365 } 4366 if (def != NULL) { 4367 req->sym_out = def; 4368 req->defobj_out = defobj; 4369 return (0); 4370 } 4371 return (ESRCH); 4372 } 4373 4374 /* 4375 * Search the chain of DAGS cointed to by the given Needed_Entry 4376 * for a symbol of the given name. Each DAG is scanned completely 4377 * before advancing to the next one. Returns a pointer to the symbol, 4378 * or NULL if no definition was found. 4379 */ 4380 static int 4381 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4382 { 4383 const Elf_Sym *def; 4384 const Needed_Entry *n; 4385 const Obj_Entry *defobj; 4386 SymLook req1; 4387 int res; 4388 4389 def = NULL; 4390 defobj = NULL; 4391 symlook_init_from_req(&req1, req); 4392 for (n = needed; n != NULL; n = n->next) { 4393 if (n->obj == NULL || 4394 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4395 continue; 4396 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4397 def = req1.sym_out; 4398 defobj = req1.defobj_out; 4399 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4400 break; 4401 } 4402 } 4403 if (def != NULL) { 4404 req->sym_out = def; 4405 req->defobj_out = defobj; 4406 return (0); 4407 } 4408 return (ESRCH); 4409 } 4410 4411 /* 4412 * Search the symbol table of a single shared object for a symbol of 4413 * the given name and version, if requested. Returns a pointer to the 4414 * symbol, or NULL if no definition was found. If the object is 4415 * filter, return filtered symbol from filtee. 4416 * 4417 * The symbol's hash value is passed in for efficiency reasons; that 4418 * eliminates many recomputations of the hash value. 4419 */ 4420 int 4421 symlook_obj(SymLook *req, const Obj_Entry *obj) 4422 { 4423 DoneList donelist; 4424 SymLook req1; 4425 int flags, res, mres; 4426 4427 /* 4428 * If there is at least one valid hash at this point, we prefer to 4429 * use the faster GNU version if available. 4430 */ 4431 if (obj->valid_hash_gnu) 4432 mres = symlook_obj1_gnu(req, obj); 4433 else if (obj->valid_hash_sysv) 4434 mres = symlook_obj1_sysv(req, obj); 4435 else 4436 return (EINVAL); 4437 4438 if (mres == 0) { 4439 if (obj->needed_filtees != NULL) { 4440 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4441 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4442 donelist_init(&donelist); 4443 symlook_init_from_req(&req1, req); 4444 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4445 if (res == 0) { 4446 req->sym_out = req1.sym_out; 4447 req->defobj_out = req1.defobj_out; 4448 } 4449 return (res); 4450 } 4451 if (obj->needed_aux_filtees != NULL) { 4452 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4453 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4454 donelist_init(&donelist); 4455 symlook_init_from_req(&req1, req); 4456 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4457 if (res == 0) { 4458 req->sym_out = req1.sym_out; 4459 req->defobj_out = req1.defobj_out; 4460 return (res); 4461 } 4462 } 4463 } 4464 return (mres); 4465 } 4466 4467 /* Symbol match routine common to both hash functions */ 4468 static bool 4469 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4470 const unsigned long symnum) 4471 { 4472 Elf_Versym verndx; 4473 const Elf_Sym *symp; 4474 const char *strp; 4475 4476 symp = obj->symtab + symnum; 4477 strp = obj->strtab + symp->st_name; 4478 4479 switch (ELF_ST_TYPE(symp->st_info)) { 4480 case STT_FUNC: 4481 case STT_NOTYPE: 4482 case STT_OBJECT: 4483 case STT_COMMON: 4484 case STT_GNU_IFUNC: 4485 if (symp->st_value == 0) 4486 return (false); 4487 /* fallthrough */ 4488 case STT_TLS: 4489 if (symp->st_shndx != SHN_UNDEF) 4490 break; 4491 #ifndef __mips__ 4492 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4493 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4494 break; 4495 #endif 4496 /* fallthrough */ 4497 default: 4498 return (false); 4499 } 4500 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4501 return (false); 4502 4503 if (req->ventry == NULL) { 4504 if (obj->versyms != NULL) { 4505 verndx = VER_NDX(obj->versyms[symnum]); 4506 if (verndx > obj->vernum) { 4507 _rtld_error( 4508 "%s: symbol %s references wrong version %d", 4509 obj->path, obj->strtab + symnum, verndx); 4510 return (false); 4511 } 4512 /* 4513 * If we are not called from dlsym (i.e. this 4514 * is a normal relocation from unversioned 4515 * binary), accept the symbol immediately if 4516 * it happens to have first version after this 4517 * shared object became versioned. Otherwise, 4518 * if symbol is versioned and not hidden, 4519 * remember it. If it is the only symbol with 4520 * this name exported by the shared object, it 4521 * will be returned as a match by the calling 4522 * function. If symbol is global (verndx < 2) 4523 * accept it unconditionally. 4524 */ 4525 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4526 verndx == VER_NDX_GIVEN) { 4527 result->sym_out = symp; 4528 return (true); 4529 } 4530 else if (verndx >= VER_NDX_GIVEN) { 4531 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4532 == 0) { 4533 if (result->vsymp == NULL) 4534 result->vsymp = symp; 4535 result->vcount++; 4536 } 4537 return (false); 4538 } 4539 } 4540 result->sym_out = symp; 4541 return (true); 4542 } 4543 if (obj->versyms == NULL) { 4544 if (object_match_name(obj, req->ventry->name)) { 4545 _rtld_error("%s: object %s should provide version %s " 4546 "for symbol %s", obj_rtld.path, obj->path, 4547 req->ventry->name, obj->strtab + symnum); 4548 return (false); 4549 } 4550 } else { 4551 verndx = VER_NDX(obj->versyms[symnum]); 4552 if (verndx > obj->vernum) { 4553 _rtld_error("%s: symbol %s references wrong version %d", 4554 obj->path, obj->strtab + symnum, verndx); 4555 return (false); 4556 } 4557 if (obj->vertab[verndx].hash != req->ventry->hash || 4558 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4559 /* 4560 * Version does not match. Look if this is a 4561 * global symbol and if it is not hidden. If 4562 * global symbol (verndx < 2) is available, 4563 * use it. Do not return symbol if we are 4564 * called by dlvsym, because dlvsym looks for 4565 * a specific version and default one is not 4566 * what dlvsym wants. 4567 */ 4568 if ((req->flags & SYMLOOK_DLSYM) || 4569 (verndx >= VER_NDX_GIVEN) || 4570 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4571 return (false); 4572 } 4573 } 4574 result->sym_out = symp; 4575 return (true); 4576 } 4577 4578 /* 4579 * Search for symbol using SysV hash function. 4580 * obj->buckets is known not to be NULL at this point; the test for this was 4581 * performed with the obj->valid_hash_sysv assignment. 4582 */ 4583 static int 4584 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4585 { 4586 unsigned long symnum; 4587 Sym_Match_Result matchres; 4588 4589 matchres.sym_out = NULL; 4590 matchres.vsymp = NULL; 4591 matchres.vcount = 0; 4592 4593 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4594 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4595 if (symnum >= obj->nchains) 4596 return (ESRCH); /* Bad object */ 4597 4598 if (matched_symbol(req, obj, &matchres, symnum)) { 4599 req->sym_out = matchres.sym_out; 4600 req->defobj_out = obj; 4601 return (0); 4602 } 4603 } 4604 if (matchres.vcount == 1) { 4605 req->sym_out = matchres.vsymp; 4606 req->defobj_out = obj; 4607 return (0); 4608 } 4609 return (ESRCH); 4610 } 4611 4612 /* Search for symbol using GNU hash function */ 4613 static int 4614 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4615 { 4616 Elf_Addr bloom_word; 4617 const Elf32_Word *hashval; 4618 Elf32_Word bucket; 4619 Sym_Match_Result matchres; 4620 unsigned int h1, h2; 4621 unsigned long symnum; 4622 4623 matchres.sym_out = NULL; 4624 matchres.vsymp = NULL; 4625 matchres.vcount = 0; 4626 4627 /* Pick right bitmask word from Bloom filter array */ 4628 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4629 obj->maskwords_bm_gnu]; 4630 4631 /* Calculate modulus word size of gnu hash and its derivative */ 4632 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4633 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4634 4635 /* Filter out the "definitely not in set" queries */ 4636 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4637 return (ESRCH); 4638 4639 /* Locate hash chain and corresponding value element*/ 4640 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4641 if (bucket == 0) 4642 return (ESRCH); 4643 hashval = &obj->chain_zero_gnu[bucket]; 4644 do { 4645 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4646 symnum = hashval - obj->chain_zero_gnu; 4647 if (matched_symbol(req, obj, &matchres, symnum)) { 4648 req->sym_out = matchres.sym_out; 4649 req->defobj_out = obj; 4650 return (0); 4651 } 4652 } 4653 } while ((*hashval++ & 1) == 0); 4654 if (matchres.vcount == 1) { 4655 req->sym_out = matchres.vsymp; 4656 req->defobj_out = obj; 4657 return (0); 4658 } 4659 return (ESRCH); 4660 } 4661 4662 static void 4663 trace_loaded_objects(Obj_Entry *obj) 4664 { 4665 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4666 int c; 4667 4668 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4669 main_local = ""; 4670 4671 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4672 fmt1 = "\t%o => %p (%x)\n"; 4673 4674 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4675 fmt2 = "\t%o (%x)\n"; 4676 4677 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4678 4679 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4680 Needed_Entry *needed; 4681 const char *name, *path; 4682 bool is_lib; 4683 4684 if (obj->marker) 4685 continue; 4686 if (list_containers && obj->needed != NULL) 4687 rtld_printf("%s:\n", obj->path); 4688 for (needed = obj->needed; needed; needed = needed->next) { 4689 if (needed->obj != NULL) { 4690 if (needed->obj->traced && !list_containers) 4691 continue; 4692 needed->obj->traced = true; 4693 path = needed->obj->path; 4694 } else 4695 path = "not found"; 4696 4697 name = obj->strtab + needed->name; 4698 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4699 4700 fmt = is_lib ? fmt1 : fmt2; 4701 while ((c = *fmt++) != '\0') { 4702 switch (c) { 4703 default: 4704 rtld_putchar(c); 4705 continue; 4706 case '\\': 4707 switch (c = *fmt) { 4708 case '\0': 4709 continue; 4710 case 'n': 4711 rtld_putchar('\n'); 4712 break; 4713 case 't': 4714 rtld_putchar('\t'); 4715 break; 4716 } 4717 break; 4718 case '%': 4719 switch (c = *fmt) { 4720 case '\0': 4721 continue; 4722 case '%': 4723 default: 4724 rtld_putchar(c); 4725 break; 4726 case 'A': 4727 rtld_putstr(main_local); 4728 break; 4729 case 'a': 4730 rtld_putstr(obj_main->path); 4731 break; 4732 case 'o': 4733 rtld_putstr(name); 4734 break; 4735 #if 0 4736 case 'm': 4737 rtld_printf("%d", sodp->sod_major); 4738 break; 4739 case 'n': 4740 rtld_printf("%d", sodp->sod_minor); 4741 break; 4742 #endif 4743 case 'p': 4744 rtld_putstr(path); 4745 break; 4746 case 'x': 4747 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4748 0); 4749 break; 4750 } 4751 break; 4752 } 4753 ++fmt; 4754 } 4755 } 4756 } 4757 } 4758 4759 /* 4760 * Unload a dlopened object and its dependencies from memory and from 4761 * our data structures. It is assumed that the DAG rooted in the 4762 * object has already been unreferenced, and that the object has a 4763 * reference count of 0. 4764 */ 4765 static void 4766 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4767 { 4768 Obj_Entry marker, *obj, *next; 4769 4770 assert(root->refcount == 0); 4771 4772 /* 4773 * Pass over the DAG removing unreferenced objects from 4774 * appropriate lists. 4775 */ 4776 unlink_object(root); 4777 4778 /* Unmap all objects that are no longer referenced. */ 4779 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4780 next = TAILQ_NEXT(obj, next); 4781 if (obj->marker || obj->refcount != 0) 4782 continue; 4783 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4784 obj->mapsize, 0, obj->path); 4785 dbg("unloading \"%s\"", obj->path); 4786 /* 4787 * Unlink the object now to prevent new references from 4788 * being acquired while the bind lock is dropped in 4789 * recursive dlclose() invocations. 4790 */ 4791 TAILQ_REMOVE(&obj_list, obj, next); 4792 obj_count--; 4793 4794 if (obj->filtees_loaded) { 4795 if (next != NULL) { 4796 init_marker(&marker); 4797 TAILQ_INSERT_BEFORE(next, &marker, next); 4798 unload_filtees(obj, lockstate); 4799 next = TAILQ_NEXT(&marker, next); 4800 TAILQ_REMOVE(&obj_list, &marker, next); 4801 } else 4802 unload_filtees(obj, lockstate); 4803 } 4804 release_object(obj); 4805 } 4806 } 4807 4808 static void 4809 unlink_object(Obj_Entry *root) 4810 { 4811 Objlist_Entry *elm; 4812 4813 if (root->refcount == 0) { 4814 /* Remove the object from the RTLD_GLOBAL list. */ 4815 objlist_remove(&list_global, root); 4816 4817 /* Remove the object from all objects' DAG lists. */ 4818 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4819 objlist_remove(&elm->obj->dldags, root); 4820 if (elm->obj != root) 4821 unlink_object(elm->obj); 4822 } 4823 } 4824 } 4825 4826 static void 4827 ref_dag(Obj_Entry *root) 4828 { 4829 Objlist_Entry *elm; 4830 4831 assert(root->dag_inited); 4832 STAILQ_FOREACH(elm, &root->dagmembers, link) 4833 elm->obj->refcount++; 4834 } 4835 4836 static void 4837 unref_dag(Obj_Entry *root) 4838 { 4839 Objlist_Entry *elm; 4840 4841 assert(root->dag_inited); 4842 STAILQ_FOREACH(elm, &root->dagmembers, link) 4843 elm->obj->refcount--; 4844 } 4845 4846 /* 4847 * Common code for MD __tls_get_addr(). 4848 */ 4849 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4850 static void * 4851 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4852 { 4853 Elf_Addr *newdtv, *dtv; 4854 RtldLockState lockstate; 4855 int to_copy; 4856 4857 dtv = *dtvp; 4858 /* Check dtv generation in case new modules have arrived */ 4859 if (dtv[0] != tls_dtv_generation) { 4860 wlock_acquire(rtld_bind_lock, &lockstate); 4861 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4862 to_copy = dtv[1]; 4863 if (to_copy > tls_max_index) 4864 to_copy = tls_max_index; 4865 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4866 newdtv[0] = tls_dtv_generation; 4867 newdtv[1] = tls_max_index; 4868 free(dtv); 4869 lock_release(rtld_bind_lock, &lockstate); 4870 dtv = *dtvp = newdtv; 4871 } 4872 4873 /* Dynamically allocate module TLS if necessary */ 4874 if (dtv[index + 1] == 0) { 4875 /* Signal safe, wlock will block out signals. */ 4876 wlock_acquire(rtld_bind_lock, &lockstate); 4877 if (!dtv[index + 1]) 4878 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4879 lock_release(rtld_bind_lock, &lockstate); 4880 } 4881 return ((void *)(dtv[index + 1] + offset)); 4882 } 4883 4884 void * 4885 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4886 { 4887 Elf_Addr *dtv; 4888 4889 dtv = *dtvp; 4890 /* Check dtv generation in case new modules have arrived */ 4891 if (__predict_true(dtv[0] == tls_dtv_generation && 4892 dtv[index + 1] != 0)) 4893 return ((void *)(dtv[index + 1] + offset)); 4894 return (tls_get_addr_slow(dtvp, index, offset)); 4895 } 4896 4897 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4898 defined(__powerpc__) || defined(__riscv) 4899 4900 /* 4901 * Return pointer to allocated TLS block 4902 */ 4903 static void * 4904 get_tls_block_ptr(void *tcb, size_t tcbsize) 4905 { 4906 size_t extra_size, post_size, pre_size, tls_block_size; 4907 size_t tls_init_align; 4908 4909 tls_init_align = MAX(obj_main->tlsalign, 1); 4910 4911 /* Compute fragments sizes. */ 4912 extra_size = tcbsize - TLS_TCB_SIZE; 4913 post_size = calculate_tls_post_size(tls_init_align); 4914 tls_block_size = tcbsize + post_size; 4915 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4916 4917 return ((char *)tcb - pre_size - extra_size); 4918 } 4919 4920 /* 4921 * Allocate Static TLS using the Variant I method. 4922 * 4923 * For details on the layout, see lib/libc/gen/tls.c. 4924 * 4925 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4926 * it is based on tls_last_offset, and TLS offsets here are really TCB 4927 * offsets, whereas libc's tls_static_space is just the executable's static 4928 * TLS segment. 4929 */ 4930 void * 4931 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4932 { 4933 Obj_Entry *obj; 4934 char *tls_block; 4935 Elf_Addr *dtv, **tcb; 4936 Elf_Addr addr; 4937 Elf_Addr i; 4938 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4939 size_t tls_init_align, tls_init_offset; 4940 4941 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4942 return (oldtcb); 4943 4944 assert(tcbsize >= TLS_TCB_SIZE); 4945 maxalign = MAX(tcbalign, tls_static_max_align); 4946 tls_init_align = MAX(obj_main->tlsalign, 1); 4947 4948 /* Compute fragmets sizes. */ 4949 extra_size = tcbsize - TLS_TCB_SIZE; 4950 post_size = calculate_tls_post_size(tls_init_align); 4951 tls_block_size = tcbsize + post_size; 4952 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4953 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4954 4955 /* Allocate whole TLS block */ 4956 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4957 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4958 4959 if (oldtcb != NULL) { 4960 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4961 tls_static_space); 4962 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4963 4964 /* Adjust the DTV. */ 4965 dtv = tcb[0]; 4966 for (i = 0; i < dtv[1]; i++) { 4967 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4968 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4969 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4970 } 4971 } 4972 } else { 4973 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4974 tcb[0] = dtv; 4975 dtv[0] = tls_dtv_generation; 4976 dtv[1] = tls_max_index; 4977 4978 for (obj = globallist_curr(objs); obj != NULL; 4979 obj = globallist_next(obj)) { 4980 if (obj->tlsoffset == 0) 4981 continue; 4982 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4983 addr = (Elf_Addr)tcb + obj->tlsoffset; 4984 if (tls_init_offset > 0) 4985 memset((void *)addr, 0, tls_init_offset); 4986 if (obj->tlsinitsize > 0) { 4987 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4988 obj->tlsinitsize); 4989 } 4990 if (obj->tlssize > obj->tlsinitsize) { 4991 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4992 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4993 } 4994 dtv[obj->tlsindex + 1] = addr; 4995 } 4996 } 4997 4998 return (tcb); 4999 } 5000 5001 void 5002 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5003 { 5004 Elf_Addr *dtv; 5005 Elf_Addr tlsstart, tlsend; 5006 size_t post_size; 5007 size_t dtvsize, i, tls_init_align; 5008 5009 assert(tcbsize >= TLS_TCB_SIZE); 5010 tls_init_align = MAX(obj_main->tlsalign, 1); 5011 5012 /* Compute fragments sizes. */ 5013 post_size = calculate_tls_post_size(tls_init_align); 5014 5015 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5016 tlsend = (Elf_Addr)tcb + tls_static_space; 5017 5018 dtv = *(Elf_Addr **)tcb; 5019 dtvsize = dtv[1]; 5020 for (i = 0; i < dtvsize; i++) { 5021 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5022 free((void*)dtv[i+2]); 5023 } 5024 } 5025 free(dtv); 5026 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5027 } 5028 5029 #endif 5030 5031 #if defined(__i386__) || defined(__amd64__) 5032 5033 /* 5034 * Allocate Static TLS using the Variant II method. 5035 */ 5036 void * 5037 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5038 { 5039 Obj_Entry *obj; 5040 size_t size, ralign; 5041 char *tls; 5042 Elf_Addr *dtv, *olddtv; 5043 Elf_Addr segbase, oldsegbase, addr; 5044 size_t i; 5045 5046 ralign = tcbalign; 5047 if (tls_static_max_align > ralign) 5048 ralign = tls_static_max_align; 5049 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5050 5051 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5052 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5053 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5054 5055 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5056 ((Elf_Addr*)segbase)[0] = segbase; 5057 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5058 5059 dtv[0] = tls_dtv_generation; 5060 dtv[1] = tls_max_index; 5061 5062 if (oldtls) { 5063 /* 5064 * Copy the static TLS block over whole. 5065 */ 5066 oldsegbase = (Elf_Addr) oldtls; 5067 memcpy((void *)(segbase - tls_static_space), 5068 (const void *)(oldsegbase - tls_static_space), 5069 tls_static_space); 5070 5071 /* 5072 * If any dynamic TLS blocks have been created tls_get_addr(), 5073 * move them over. 5074 */ 5075 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5076 for (i = 0; i < olddtv[1]; i++) { 5077 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5078 dtv[i+2] = olddtv[i+2]; 5079 olddtv[i+2] = 0; 5080 } 5081 } 5082 5083 /* 5084 * We assume that this block was the one we created with 5085 * allocate_initial_tls(). 5086 */ 5087 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5088 } else { 5089 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5090 if (obj->marker || obj->tlsoffset == 0) 5091 continue; 5092 addr = segbase - obj->tlsoffset; 5093 memset((void*)(addr + obj->tlsinitsize), 5094 0, obj->tlssize - obj->tlsinitsize); 5095 if (obj->tlsinit) { 5096 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5097 obj->static_tls_copied = true; 5098 } 5099 dtv[obj->tlsindex + 1] = addr; 5100 } 5101 } 5102 5103 return (void*) segbase; 5104 } 5105 5106 void 5107 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5108 { 5109 Elf_Addr* dtv; 5110 size_t size, ralign; 5111 int dtvsize, i; 5112 Elf_Addr tlsstart, tlsend; 5113 5114 /* 5115 * Figure out the size of the initial TLS block so that we can 5116 * find stuff which ___tls_get_addr() allocated dynamically. 5117 */ 5118 ralign = tcbalign; 5119 if (tls_static_max_align > ralign) 5120 ralign = tls_static_max_align; 5121 size = roundup(tls_static_space, ralign); 5122 5123 dtv = ((Elf_Addr**)tls)[1]; 5124 dtvsize = dtv[1]; 5125 tlsend = (Elf_Addr) tls; 5126 tlsstart = tlsend - size; 5127 for (i = 0; i < dtvsize; i++) { 5128 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5129 free_aligned((void *)dtv[i + 2]); 5130 } 5131 } 5132 5133 free_aligned((void *)tlsstart); 5134 free((void*) dtv); 5135 } 5136 5137 #endif 5138 5139 /* 5140 * Allocate TLS block for module with given index. 5141 */ 5142 void * 5143 allocate_module_tls(int index) 5144 { 5145 Obj_Entry *obj; 5146 char *p; 5147 5148 TAILQ_FOREACH(obj, &obj_list, next) { 5149 if (obj->marker) 5150 continue; 5151 if (obj->tlsindex == index) 5152 break; 5153 } 5154 if (obj == NULL) { 5155 _rtld_error("Can't find module with TLS index %d", index); 5156 rtld_die(); 5157 } 5158 5159 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5160 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5161 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5162 return (p); 5163 } 5164 5165 bool 5166 allocate_tls_offset(Obj_Entry *obj) 5167 { 5168 size_t off; 5169 5170 if (obj->tls_done) 5171 return true; 5172 5173 if (obj->tlssize == 0) { 5174 obj->tls_done = true; 5175 return true; 5176 } 5177 5178 if (tls_last_offset == 0) 5179 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5180 obj->tlspoffset); 5181 else 5182 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5183 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5184 5185 /* 5186 * If we have already fixed the size of the static TLS block, we 5187 * must stay within that size. When allocating the static TLS, we 5188 * leave a small amount of space spare to be used for dynamically 5189 * loading modules which use static TLS. 5190 */ 5191 if (tls_static_space != 0) { 5192 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5193 return false; 5194 } else if (obj->tlsalign > tls_static_max_align) { 5195 tls_static_max_align = obj->tlsalign; 5196 } 5197 5198 tls_last_offset = obj->tlsoffset = off; 5199 tls_last_size = obj->tlssize; 5200 obj->tls_done = true; 5201 5202 return true; 5203 } 5204 5205 void 5206 free_tls_offset(Obj_Entry *obj) 5207 { 5208 5209 /* 5210 * If we were the last thing to allocate out of the static TLS 5211 * block, we give our space back to the 'allocator'. This is a 5212 * simplistic workaround to allow libGL.so.1 to be loaded and 5213 * unloaded multiple times. 5214 */ 5215 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5216 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5217 tls_last_offset -= obj->tlssize; 5218 tls_last_size = 0; 5219 } 5220 } 5221 5222 void * 5223 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5224 { 5225 void *ret; 5226 RtldLockState lockstate; 5227 5228 wlock_acquire(rtld_bind_lock, &lockstate); 5229 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5230 tcbsize, tcbalign); 5231 lock_release(rtld_bind_lock, &lockstate); 5232 return (ret); 5233 } 5234 5235 void 5236 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5237 { 5238 RtldLockState lockstate; 5239 5240 wlock_acquire(rtld_bind_lock, &lockstate); 5241 free_tls(tcb, tcbsize, tcbalign); 5242 lock_release(rtld_bind_lock, &lockstate); 5243 } 5244 5245 static void 5246 object_add_name(Obj_Entry *obj, const char *name) 5247 { 5248 Name_Entry *entry; 5249 size_t len; 5250 5251 len = strlen(name); 5252 entry = malloc(sizeof(Name_Entry) + len); 5253 5254 if (entry != NULL) { 5255 strcpy(entry->name, name); 5256 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5257 } 5258 } 5259 5260 static int 5261 object_match_name(const Obj_Entry *obj, const char *name) 5262 { 5263 Name_Entry *entry; 5264 5265 STAILQ_FOREACH(entry, &obj->names, link) { 5266 if (strcmp(name, entry->name) == 0) 5267 return (1); 5268 } 5269 return (0); 5270 } 5271 5272 static Obj_Entry * 5273 locate_dependency(const Obj_Entry *obj, const char *name) 5274 { 5275 const Objlist_Entry *entry; 5276 const Needed_Entry *needed; 5277 5278 STAILQ_FOREACH(entry, &list_main, link) { 5279 if (object_match_name(entry->obj, name)) 5280 return entry->obj; 5281 } 5282 5283 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5284 if (strcmp(obj->strtab + needed->name, name) == 0 || 5285 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5286 /* 5287 * If there is DT_NEEDED for the name we are looking for, 5288 * we are all set. Note that object might not be found if 5289 * dependency was not loaded yet, so the function can 5290 * return NULL here. This is expected and handled 5291 * properly by the caller. 5292 */ 5293 return (needed->obj); 5294 } 5295 } 5296 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5297 obj->path, name); 5298 rtld_die(); 5299 } 5300 5301 static int 5302 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5303 const Elf_Vernaux *vna) 5304 { 5305 const Elf_Verdef *vd; 5306 const char *vername; 5307 5308 vername = refobj->strtab + vna->vna_name; 5309 vd = depobj->verdef; 5310 if (vd == NULL) { 5311 _rtld_error("%s: version %s required by %s not defined", 5312 depobj->path, vername, refobj->path); 5313 return (-1); 5314 } 5315 for (;;) { 5316 if (vd->vd_version != VER_DEF_CURRENT) { 5317 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5318 depobj->path, vd->vd_version); 5319 return (-1); 5320 } 5321 if (vna->vna_hash == vd->vd_hash) { 5322 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5323 ((const char *)vd + vd->vd_aux); 5324 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5325 return (0); 5326 } 5327 if (vd->vd_next == 0) 5328 break; 5329 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5330 } 5331 if (vna->vna_flags & VER_FLG_WEAK) 5332 return (0); 5333 _rtld_error("%s: version %s required by %s not found", 5334 depobj->path, vername, refobj->path); 5335 return (-1); 5336 } 5337 5338 static int 5339 rtld_verify_object_versions(Obj_Entry *obj) 5340 { 5341 const Elf_Verneed *vn; 5342 const Elf_Verdef *vd; 5343 const Elf_Verdaux *vda; 5344 const Elf_Vernaux *vna; 5345 const Obj_Entry *depobj; 5346 int maxvernum, vernum; 5347 5348 if (obj->ver_checked) 5349 return (0); 5350 obj->ver_checked = true; 5351 5352 maxvernum = 0; 5353 /* 5354 * Walk over defined and required version records and figure out 5355 * max index used by any of them. Do very basic sanity checking 5356 * while there. 5357 */ 5358 vn = obj->verneed; 5359 while (vn != NULL) { 5360 if (vn->vn_version != VER_NEED_CURRENT) { 5361 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5362 obj->path, vn->vn_version); 5363 return (-1); 5364 } 5365 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5366 for (;;) { 5367 vernum = VER_NEED_IDX(vna->vna_other); 5368 if (vernum > maxvernum) 5369 maxvernum = vernum; 5370 if (vna->vna_next == 0) 5371 break; 5372 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5373 } 5374 if (vn->vn_next == 0) 5375 break; 5376 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5377 } 5378 5379 vd = obj->verdef; 5380 while (vd != NULL) { 5381 if (vd->vd_version != VER_DEF_CURRENT) { 5382 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5383 obj->path, vd->vd_version); 5384 return (-1); 5385 } 5386 vernum = VER_DEF_IDX(vd->vd_ndx); 5387 if (vernum > maxvernum) 5388 maxvernum = vernum; 5389 if (vd->vd_next == 0) 5390 break; 5391 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5392 } 5393 5394 if (maxvernum == 0) 5395 return (0); 5396 5397 /* 5398 * Store version information in array indexable by version index. 5399 * Verify that object version requirements are satisfied along the 5400 * way. 5401 */ 5402 obj->vernum = maxvernum + 1; 5403 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5404 5405 vd = obj->verdef; 5406 while (vd != NULL) { 5407 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5408 vernum = VER_DEF_IDX(vd->vd_ndx); 5409 assert(vernum <= maxvernum); 5410 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5411 obj->vertab[vernum].hash = vd->vd_hash; 5412 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5413 obj->vertab[vernum].file = NULL; 5414 obj->vertab[vernum].flags = 0; 5415 } 5416 if (vd->vd_next == 0) 5417 break; 5418 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5419 } 5420 5421 vn = obj->verneed; 5422 while (vn != NULL) { 5423 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5424 if (depobj == NULL) 5425 return (-1); 5426 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5427 for (;;) { 5428 if (check_object_provided_version(obj, depobj, vna)) 5429 return (-1); 5430 vernum = VER_NEED_IDX(vna->vna_other); 5431 assert(vernum <= maxvernum); 5432 obj->vertab[vernum].hash = vna->vna_hash; 5433 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5434 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5435 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5436 VER_INFO_HIDDEN : 0; 5437 if (vna->vna_next == 0) 5438 break; 5439 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5440 } 5441 if (vn->vn_next == 0) 5442 break; 5443 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5444 } 5445 return 0; 5446 } 5447 5448 static int 5449 rtld_verify_versions(const Objlist *objlist) 5450 { 5451 Objlist_Entry *entry; 5452 int rc; 5453 5454 rc = 0; 5455 STAILQ_FOREACH(entry, objlist, link) { 5456 /* 5457 * Skip dummy objects or objects that have their version requirements 5458 * already checked. 5459 */ 5460 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5461 continue; 5462 if (rtld_verify_object_versions(entry->obj) == -1) { 5463 rc = -1; 5464 if (ld_tracing == NULL) 5465 break; 5466 } 5467 } 5468 if (rc == 0 || ld_tracing != NULL) 5469 rc = rtld_verify_object_versions(&obj_rtld); 5470 return rc; 5471 } 5472 5473 const Ver_Entry * 5474 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5475 { 5476 Elf_Versym vernum; 5477 5478 if (obj->vertab) { 5479 vernum = VER_NDX(obj->versyms[symnum]); 5480 if (vernum >= obj->vernum) { 5481 _rtld_error("%s: symbol %s has wrong verneed value %d", 5482 obj->path, obj->strtab + symnum, vernum); 5483 } else if (obj->vertab[vernum].hash != 0) { 5484 return &obj->vertab[vernum]; 5485 } 5486 } 5487 return NULL; 5488 } 5489 5490 int 5491 _rtld_get_stack_prot(void) 5492 { 5493 5494 return (stack_prot); 5495 } 5496 5497 int 5498 _rtld_is_dlopened(void *arg) 5499 { 5500 Obj_Entry *obj; 5501 RtldLockState lockstate; 5502 int res; 5503 5504 rlock_acquire(rtld_bind_lock, &lockstate); 5505 obj = dlcheck(arg); 5506 if (obj == NULL) 5507 obj = obj_from_addr(arg); 5508 if (obj == NULL) { 5509 _rtld_error("No shared object contains address"); 5510 lock_release(rtld_bind_lock, &lockstate); 5511 return (-1); 5512 } 5513 res = obj->dlopened ? 1 : 0; 5514 lock_release(rtld_bind_lock, &lockstate); 5515 return (res); 5516 } 5517 5518 static int 5519 obj_remap_relro(Obj_Entry *obj, int prot) 5520 { 5521 5522 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5523 prot) == -1) { 5524 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5525 obj->path, prot, rtld_strerror(errno)); 5526 return (-1); 5527 } 5528 return (0); 5529 } 5530 5531 static int 5532 obj_disable_relro(Obj_Entry *obj) 5533 { 5534 5535 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5536 } 5537 5538 static int 5539 obj_enforce_relro(Obj_Entry *obj) 5540 { 5541 5542 return (obj_remap_relro(obj, PROT_READ)); 5543 } 5544 5545 static void 5546 map_stacks_exec(RtldLockState *lockstate) 5547 { 5548 void (*thr_map_stacks_exec)(void); 5549 5550 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5551 return; 5552 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5553 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5554 if (thr_map_stacks_exec != NULL) { 5555 stack_prot |= PROT_EXEC; 5556 thr_map_stacks_exec(); 5557 } 5558 } 5559 5560 static void 5561 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5562 { 5563 Objlist_Entry *elm; 5564 Obj_Entry *obj; 5565 void (*distrib)(size_t, void *, size_t, size_t); 5566 5567 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5568 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5569 if (distrib == NULL) 5570 return; 5571 STAILQ_FOREACH(elm, list, link) { 5572 obj = elm->obj; 5573 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5574 continue; 5575 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5576 obj->tlssize); 5577 obj->static_tls_copied = true; 5578 } 5579 } 5580 5581 void 5582 symlook_init(SymLook *dst, const char *name) 5583 { 5584 5585 bzero(dst, sizeof(*dst)); 5586 dst->name = name; 5587 dst->hash = elf_hash(name); 5588 dst->hash_gnu = gnu_hash(name); 5589 } 5590 5591 static void 5592 symlook_init_from_req(SymLook *dst, const SymLook *src) 5593 { 5594 5595 dst->name = src->name; 5596 dst->hash = src->hash; 5597 dst->hash_gnu = src->hash_gnu; 5598 dst->ventry = src->ventry; 5599 dst->flags = src->flags; 5600 dst->defobj_out = NULL; 5601 dst->sym_out = NULL; 5602 dst->lockstate = src->lockstate; 5603 } 5604 5605 static int 5606 open_binary_fd(const char *argv0, bool search_in_path, 5607 const char **binpath_res) 5608 { 5609 char *binpath, *pathenv, *pe, *res1; 5610 const char *res; 5611 int fd; 5612 5613 binpath = NULL; 5614 res = NULL; 5615 if (search_in_path && strchr(argv0, '/') == NULL) { 5616 binpath = xmalloc(PATH_MAX); 5617 pathenv = getenv("PATH"); 5618 if (pathenv == NULL) { 5619 _rtld_error("-p and no PATH environment variable"); 5620 rtld_die(); 5621 } 5622 pathenv = strdup(pathenv); 5623 if (pathenv == NULL) { 5624 _rtld_error("Cannot allocate memory"); 5625 rtld_die(); 5626 } 5627 fd = -1; 5628 errno = ENOENT; 5629 while ((pe = strsep(&pathenv, ":")) != NULL) { 5630 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5631 continue; 5632 if (binpath[0] != '\0' && 5633 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5634 continue; 5635 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5636 continue; 5637 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5638 if (fd != -1 || errno != ENOENT) { 5639 res = binpath; 5640 break; 5641 } 5642 } 5643 free(pathenv); 5644 } else { 5645 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5646 res = argv0; 5647 } 5648 5649 if (fd == -1) { 5650 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5651 rtld_die(); 5652 } 5653 if (res != NULL && res[0] != '/') { 5654 res1 = xmalloc(PATH_MAX); 5655 if (realpath(res, res1) != NULL) { 5656 if (res != argv0) 5657 free(__DECONST(char *, res)); 5658 res = res1; 5659 } else { 5660 free(res1); 5661 } 5662 } 5663 *binpath_res = res; 5664 return (fd); 5665 } 5666 5667 /* 5668 * Parse a set of command-line arguments. 5669 */ 5670 static int 5671 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5672 const char **argv0) 5673 { 5674 const char *arg; 5675 char machine[64]; 5676 size_t sz; 5677 int arglen, fd, i, j, mib[2]; 5678 char opt; 5679 bool seen_b, seen_f; 5680 5681 dbg("Parsing command-line arguments"); 5682 *use_pathp = false; 5683 *fdp = -1; 5684 seen_b = seen_f = false; 5685 5686 for (i = 1; i < argc; i++ ) { 5687 arg = argv[i]; 5688 dbg("argv[%d]: '%s'", i, arg); 5689 5690 /* 5691 * rtld arguments end with an explicit "--" or with the first 5692 * non-prefixed argument. 5693 */ 5694 if (strcmp(arg, "--") == 0) { 5695 i++; 5696 break; 5697 } 5698 if (arg[0] != '-') 5699 break; 5700 5701 /* 5702 * All other arguments are single-character options that can 5703 * be combined, so we need to search through `arg` for them. 5704 */ 5705 arglen = strlen(arg); 5706 for (j = 1; j < arglen; j++) { 5707 opt = arg[j]; 5708 if (opt == 'h') { 5709 print_usage(argv[0]); 5710 _exit(0); 5711 } else if (opt == 'b') { 5712 if (seen_f) { 5713 _rtld_error("Both -b and -f specified"); 5714 rtld_die(); 5715 } 5716 i++; 5717 *argv0 = argv[i]; 5718 seen_b = true; 5719 break; 5720 } else if (opt == 'f') { 5721 if (seen_b) { 5722 _rtld_error("Both -b and -f specified"); 5723 rtld_die(); 5724 } 5725 5726 /* 5727 * -f XX can be used to specify a 5728 * descriptor for the binary named at 5729 * the command line (i.e., the later 5730 * argument will specify the process 5731 * name but the descriptor is what 5732 * will actually be executed). 5733 * 5734 * -f must be the last option in, e.g., -abcf. 5735 */ 5736 if (j != arglen - 1) { 5737 _rtld_error("Invalid options: %s", arg); 5738 rtld_die(); 5739 } 5740 i++; 5741 fd = parse_integer(argv[i]); 5742 if (fd == -1) { 5743 _rtld_error( 5744 "Invalid file descriptor: '%s'", 5745 argv[i]); 5746 rtld_die(); 5747 } 5748 *fdp = fd; 5749 seen_f = true; 5750 break; 5751 } else if (opt == 'p') { 5752 *use_pathp = true; 5753 } else if (opt == 'v') { 5754 machine[0] = '\0'; 5755 mib[0] = CTL_HW; 5756 mib[1] = HW_MACHINE; 5757 sz = sizeof(machine); 5758 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5759 rtld_printf( 5760 "FreeBSD ld-elf.so.1 %s\n" 5761 "FreeBSD_version %d\n" 5762 "Default lib path %s\n" 5763 "Env prefix %s\n" 5764 "Hint file %s\n" 5765 "libmap file %s\n", 5766 machine, 5767 __FreeBSD_version, ld_standard_library_path, 5768 ld_env_prefix, ld_elf_hints_default, 5769 ld_path_libmap_conf); 5770 _exit(0); 5771 } else { 5772 _rtld_error("Invalid argument: '%s'", arg); 5773 print_usage(argv[0]); 5774 rtld_die(); 5775 } 5776 } 5777 } 5778 5779 if (!seen_b) 5780 *argv0 = argv[i]; 5781 return (i); 5782 } 5783 5784 /* 5785 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5786 */ 5787 static int 5788 parse_integer(const char *str) 5789 { 5790 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5791 const char *orig; 5792 int n; 5793 char c; 5794 5795 orig = str; 5796 n = 0; 5797 for (c = *str; c != '\0'; c = *++str) { 5798 if (c < '0' || c > '9') 5799 return (-1); 5800 5801 n *= RADIX; 5802 n += c - '0'; 5803 } 5804 5805 /* Make sure we actually parsed something. */ 5806 if (str == orig) 5807 return (-1); 5808 return (n); 5809 } 5810 5811 static void 5812 print_usage(const char *argv0) 5813 { 5814 5815 rtld_printf( 5816 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5817 "\n" 5818 "Options:\n" 5819 " -h Display this help message\n" 5820 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5821 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5822 " -p Search in PATH for named binary\n" 5823 " -v Display identification information\n" 5824 " -- End of RTLD options\n" 5825 " <binary> Name of process to execute\n" 5826 " <args> Arguments to the executed process\n", argv0); 5827 } 5828 5829 /* 5830 * Overrides for libc_pic-provided functions. 5831 */ 5832 5833 int 5834 __getosreldate(void) 5835 { 5836 size_t len; 5837 int oid[2]; 5838 int error, osrel; 5839 5840 if (osreldate != 0) 5841 return (osreldate); 5842 5843 oid[0] = CTL_KERN; 5844 oid[1] = KERN_OSRELDATE; 5845 osrel = 0; 5846 len = sizeof(osrel); 5847 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5848 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5849 osreldate = osrel; 5850 return (osreldate); 5851 } 5852 const char * 5853 rtld_strerror(int errnum) 5854 { 5855 5856 if (errnum < 0 || errnum >= sys_nerr) 5857 return ("Unknown error"); 5858 return (sys_errlist[errnum]); 5859 } 5860 5861 /* malloc */ 5862 void * 5863 malloc(size_t nbytes) 5864 { 5865 5866 return (__crt_malloc(nbytes)); 5867 } 5868 5869 void * 5870 calloc(size_t num, size_t size) 5871 { 5872 5873 return (__crt_calloc(num, size)); 5874 } 5875 5876 void 5877 free(void *cp) 5878 { 5879 5880 __crt_free(cp); 5881 } 5882 5883 void * 5884 realloc(void *cp, size_t nbytes) 5885 { 5886 5887 return (__crt_realloc(cp, nbytes)); 5888 } 5889 5890 extern int _rtld_version__FreeBSD_version __exported; 5891 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5892 5893 extern char _rtld_version_laddr_offset __exported; 5894 char _rtld_version_laddr_offset; 5895