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 /* 807 * Execute MD initializers required before we call the objects' 808 * init functions. 809 */ 810 pre_init(); 811 812 if (direct_exec) { 813 /* Set osrel for direct-execed binary */ 814 mib[0] = CTL_KERN; 815 mib[1] = KERN_PROC; 816 mib[2] = KERN_PROC_OSREL; 817 mib[3] = getpid(); 818 osrel = obj_main->osrel; 819 sz = sizeof(old_osrel); 820 dbg("setting osrel to %d", osrel); 821 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 822 } 823 824 wlock_acquire(rtld_bind_lock, &lockstate); 825 826 dbg("resolving ifuncs"); 827 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 828 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 829 rtld_die(); 830 831 rtld_exit_ptr = rtld_exit; 832 if (obj_main->crt_no_init) 833 preinit_main(); 834 objlist_call_init(&initlist, &lockstate); 835 _r_debug_postinit(&obj_main->linkmap); 836 objlist_clear(&initlist); 837 dbg("loading filtees"); 838 TAILQ_FOREACH(obj, &obj_list, next) { 839 if (obj->marker) 840 continue; 841 if (ld_loadfltr || obj->z_loadfltr) 842 load_filtees(obj, 0, &lockstate); 843 } 844 845 dbg("enforcing main obj relro"); 846 if (obj_enforce_relro(obj_main) == -1) 847 rtld_die(); 848 849 lock_release(rtld_bind_lock, &lockstate); 850 851 dbg("transferring control to program entry point = %p", obj_main->entry); 852 853 /* Return the exit procedure and the program entry point. */ 854 *exit_proc = rtld_exit_ptr; 855 *objp = obj_main; 856 return (func_ptr_type) obj_main->entry; 857 } 858 859 void * 860 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 861 { 862 void *ptr; 863 Elf_Addr target; 864 865 ptr = (void *)make_function_pointer(def, obj); 866 target = call_ifunc_resolver(ptr); 867 return ((void *)target); 868 } 869 870 /* 871 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 872 * Changes to this function should be applied there as well. 873 */ 874 Elf_Addr 875 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 876 { 877 const Elf_Rel *rel; 878 const Elf_Sym *def; 879 const Obj_Entry *defobj; 880 Elf_Addr *where; 881 Elf_Addr target; 882 RtldLockState lockstate; 883 884 rlock_acquire(rtld_bind_lock, &lockstate); 885 if (sigsetjmp(lockstate.env, 0) != 0) 886 lock_upgrade(rtld_bind_lock, &lockstate); 887 if (obj->pltrel) 888 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 889 else 890 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 891 892 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 893 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 894 NULL, &lockstate); 895 if (def == NULL) 896 rtld_die(); 897 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 898 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 899 else 900 target = (Elf_Addr)(defobj->relocbase + def->st_value); 901 902 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 903 defobj->strtab + def->st_name, basename(obj->path), 904 (void *)target, basename(defobj->path)); 905 906 /* 907 * Write the new contents for the jmpslot. Note that depending on 908 * architecture, the value which we need to return back to the 909 * lazy binding trampoline may or may not be the target 910 * address. The value returned from reloc_jmpslot() is the value 911 * that the trampoline needs. 912 */ 913 target = reloc_jmpslot(where, target, defobj, obj, rel); 914 lock_release(rtld_bind_lock, &lockstate); 915 return target; 916 } 917 918 /* 919 * Error reporting function. Use it like printf. If formats the message 920 * into a buffer, and sets things up so that the next call to dlerror() 921 * will return the message. 922 */ 923 void 924 _rtld_error(const char *fmt, ...) 925 { 926 static char buf[512]; 927 va_list ap; 928 929 va_start(ap, fmt); 930 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 931 error_message = buf; 932 va_end(ap); 933 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 934 } 935 936 /* 937 * Return a dynamically-allocated copy of the current error message, if any. 938 */ 939 static char * 940 errmsg_save(void) 941 { 942 return error_message == NULL ? NULL : xstrdup(error_message); 943 } 944 945 /* 946 * Restore the current error message from a copy which was previously saved 947 * by errmsg_save(). The copy is freed. 948 */ 949 static void 950 errmsg_restore(char *saved_msg) 951 { 952 if (saved_msg == NULL) 953 error_message = NULL; 954 else { 955 _rtld_error("%s", saved_msg); 956 free(saved_msg); 957 } 958 } 959 960 static const char * 961 basename(const char *name) 962 { 963 const char *p = strrchr(name, '/'); 964 return p != NULL ? p + 1 : name; 965 } 966 967 static struct utsname uts; 968 969 static char * 970 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 971 const char *subst, bool may_free) 972 { 973 char *p, *p1, *res, *resp; 974 int subst_len, kw_len, subst_count, old_len, new_len; 975 976 kw_len = strlen(kw); 977 978 /* 979 * First, count the number of the keyword occurrences, to 980 * preallocate the final string. 981 */ 982 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 983 p1 = strstr(p, kw); 984 if (p1 == NULL) 985 break; 986 } 987 988 /* 989 * If the keyword is not found, just return. 990 * 991 * Return non-substituted string if resolution failed. We 992 * cannot do anything more reasonable, the failure mode of the 993 * caller is unresolved library anyway. 994 */ 995 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 996 return (may_free ? real : xstrdup(real)); 997 if (obj != NULL) 998 subst = obj->origin_path; 999 1000 /* 1001 * There is indeed something to substitute. Calculate the 1002 * length of the resulting string, and allocate it. 1003 */ 1004 subst_len = strlen(subst); 1005 old_len = strlen(real); 1006 new_len = old_len + (subst_len - kw_len) * subst_count; 1007 res = xmalloc(new_len + 1); 1008 1009 /* 1010 * Now, execute the substitution loop. 1011 */ 1012 for (p = real, resp = res, *resp = '\0';;) { 1013 p1 = strstr(p, kw); 1014 if (p1 != NULL) { 1015 /* Copy the prefix before keyword. */ 1016 memcpy(resp, p, p1 - p); 1017 resp += p1 - p; 1018 /* Keyword replacement. */ 1019 memcpy(resp, subst, subst_len); 1020 resp += subst_len; 1021 *resp = '\0'; 1022 p = p1 + kw_len; 1023 } else 1024 break; 1025 } 1026 1027 /* Copy to the end of string and finish. */ 1028 strcat(resp, p); 1029 if (may_free) 1030 free(real); 1031 return (res); 1032 } 1033 1034 static char * 1035 origin_subst(Obj_Entry *obj, const char *real) 1036 { 1037 char *res1, *res2, *res3, *res4; 1038 1039 if (obj == NULL || !trust) 1040 return (xstrdup(real)); 1041 if (uts.sysname[0] == '\0') { 1042 if (uname(&uts) != 0) { 1043 _rtld_error("utsname failed: %d", errno); 1044 return (NULL); 1045 } 1046 } 1047 /* __DECONST is safe here since without may_free real is unchanged */ 1048 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1049 false); 1050 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1051 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1052 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1053 return (res4); 1054 } 1055 1056 void 1057 rtld_die(void) 1058 { 1059 const char *msg = dlerror(); 1060 1061 if (msg == NULL) 1062 msg = "Fatal error"; 1063 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1064 rtld_fdputstr(STDERR_FILENO, msg); 1065 rtld_fdputchar(STDERR_FILENO, '\n'); 1066 _exit(1); 1067 } 1068 1069 /* 1070 * Process a shared object's DYNAMIC section, and save the important 1071 * information in its Obj_Entry structure. 1072 */ 1073 static void 1074 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1075 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1076 { 1077 const Elf_Dyn *dynp; 1078 Needed_Entry **needed_tail = &obj->needed; 1079 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1080 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1081 const Elf_Hashelt *hashtab; 1082 const Elf32_Word *hashval; 1083 Elf32_Word bkt, nmaskwords; 1084 int bloom_size32; 1085 int plttype = DT_REL; 1086 1087 *dyn_rpath = NULL; 1088 *dyn_soname = NULL; 1089 *dyn_runpath = NULL; 1090 1091 obj->bind_now = false; 1092 dynp = obj->dynamic; 1093 if (dynp == NULL) 1094 return; 1095 for (; dynp->d_tag != DT_NULL; dynp++) { 1096 switch (dynp->d_tag) { 1097 1098 case DT_REL: 1099 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1100 break; 1101 1102 case DT_RELSZ: 1103 obj->relsize = dynp->d_un.d_val; 1104 break; 1105 1106 case DT_RELENT: 1107 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1108 break; 1109 1110 case DT_JMPREL: 1111 obj->pltrel = (const Elf_Rel *) 1112 (obj->relocbase + dynp->d_un.d_ptr); 1113 break; 1114 1115 case DT_PLTRELSZ: 1116 obj->pltrelsize = dynp->d_un.d_val; 1117 break; 1118 1119 case DT_RELA: 1120 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1121 break; 1122 1123 case DT_RELASZ: 1124 obj->relasize = dynp->d_un.d_val; 1125 break; 1126 1127 case DT_RELAENT: 1128 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1129 break; 1130 1131 case DT_PLTREL: 1132 plttype = dynp->d_un.d_val; 1133 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1134 break; 1135 1136 case DT_SYMTAB: 1137 obj->symtab = (const Elf_Sym *) 1138 (obj->relocbase + dynp->d_un.d_ptr); 1139 break; 1140 1141 case DT_SYMENT: 1142 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1143 break; 1144 1145 case DT_STRTAB: 1146 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1147 break; 1148 1149 case DT_STRSZ: 1150 obj->strsize = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_VERNEED: 1154 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1155 dynp->d_un.d_val); 1156 break; 1157 1158 case DT_VERNEEDNUM: 1159 obj->verneednum = dynp->d_un.d_val; 1160 break; 1161 1162 case DT_VERDEF: 1163 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1164 dynp->d_un.d_val); 1165 break; 1166 1167 case DT_VERDEFNUM: 1168 obj->verdefnum = dynp->d_un.d_val; 1169 break; 1170 1171 case DT_VERSYM: 1172 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1173 dynp->d_un.d_val); 1174 break; 1175 1176 case DT_HASH: 1177 { 1178 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1179 dynp->d_un.d_ptr); 1180 obj->nbuckets = hashtab[0]; 1181 obj->nchains = hashtab[1]; 1182 obj->buckets = hashtab + 2; 1183 obj->chains = obj->buckets + obj->nbuckets; 1184 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1185 obj->buckets != NULL; 1186 } 1187 break; 1188 1189 case DT_GNU_HASH: 1190 { 1191 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1192 dynp->d_un.d_ptr); 1193 obj->nbuckets_gnu = hashtab[0]; 1194 obj->symndx_gnu = hashtab[1]; 1195 nmaskwords = hashtab[2]; 1196 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1197 obj->maskwords_bm_gnu = nmaskwords - 1; 1198 obj->shift2_gnu = hashtab[3]; 1199 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1200 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1201 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1202 obj->symndx_gnu; 1203 /* Number of bitmask words is required to be power of 2 */ 1204 obj->valid_hash_gnu = powerof2(nmaskwords) && 1205 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1206 } 1207 break; 1208 1209 case DT_NEEDED: 1210 if (!obj->rtld) { 1211 Needed_Entry *nep = NEW(Needed_Entry); 1212 nep->name = dynp->d_un.d_val; 1213 nep->obj = NULL; 1214 nep->next = NULL; 1215 1216 *needed_tail = nep; 1217 needed_tail = &nep->next; 1218 } 1219 break; 1220 1221 case DT_FILTER: 1222 if (!obj->rtld) { 1223 Needed_Entry *nep = NEW(Needed_Entry); 1224 nep->name = dynp->d_un.d_val; 1225 nep->obj = NULL; 1226 nep->next = NULL; 1227 1228 *needed_filtees_tail = nep; 1229 needed_filtees_tail = &nep->next; 1230 1231 if (obj->linkmap.l_refname == NULL) 1232 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1233 } 1234 break; 1235 1236 case DT_AUXILIARY: 1237 if (!obj->rtld) { 1238 Needed_Entry *nep = NEW(Needed_Entry); 1239 nep->name = dynp->d_un.d_val; 1240 nep->obj = NULL; 1241 nep->next = NULL; 1242 1243 *needed_aux_filtees_tail = nep; 1244 needed_aux_filtees_tail = &nep->next; 1245 } 1246 break; 1247 1248 case DT_PLTGOT: 1249 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1250 break; 1251 1252 case DT_TEXTREL: 1253 obj->textrel = true; 1254 break; 1255 1256 case DT_SYMBOLIC: 1257 obj->symbolic = true; 1258 break; 1259 1260 case DT_RPATH: 1261 /* 1262 * We have to wait until later to process this, because we 1263 * might not have gotten the address of the string table yet. 1264 */ 1265 *dyn_rpath = dynp; 1266 break; 1267 1268 case DT_SONAME: 1269 *dyn_soname = dynp; 1270 break; 1271 1272 case DT_RUNPATH: 1273 *dyn_runpath = dynp; 1274 break; 1275 1276 case DT_INIT: 1277 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1278 break; 1279 1280 case DT_PREINIT_ARRAY: 1281 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_PREINIT_ARRAYSZ: 1285 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1286 break; 1287 1288 case DT_INIT_ARRAY: 1289 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1290 break; 1291 1292 case DT_INIT_ARRAYSZ: 1293 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1294 break; 1295 1296 case DT_FINI: 1297 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1298 break; 1299 1300 case DT_FINI_ARRAY: 1301 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1302 break; 1303 1304 case DT_FINI_ARRAYSZ: 1305 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1306 break; 1307 1308 /* 1309 * Don't process DT_DEBUG on MIPS as the dynamic section 1310 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1311 */ 1312 1313 #ifndef __mips__ 1314 case DT_DEBUG: 1315 if (!early) 1316 dbg("Filling in DT_DEBUG entry"); 1317 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1318 break; 1319 #endif 1320 1321 case DT_FLAGS: 1322 if (dynp->d_un.d_val & DF_ORIGIN) 1323 obj->z_origin = true; 1324 if (dynp->d_un.d_val & DF_SYMBOLIC) 1325 obj->symbolic = true; 1326 if (dynp->d_un.d_val & DF_TEXTREL) 1327 obj->textrel = true; 1328 if (dynp->d_un.d_val & DF_BIND_NOW) 1329 obj->bind_now = true; 1330 if (dynp->d_un.d_val & DF_STATIC_TLS) 1331 obj->static_tls = true; 1332 break; 1333 #ifdef __mips__ 1334 case DT_MIPS_LOCAL_GOTNO: 1335 obj->local_gotno = dynp->d_un.d_val; 1336 break; 1337 1338 case DT_MIPS_SYMTABNO: 1339 obj->symtabno = dynp->d_un.d_val; 1340 break; 1341 1342 case DT_MIPS_GOTSYM: 1343 obj->gotsym = dynp->d_un.d_val; 1344 break; 1345 1346 case DT_MIPS_RLD_MAP: 1347 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1348 break; 1349 1350 case DT_MIPS_RLD_MAP_REL: 1351 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1352 // section relative to the address of the tag itself. 1353 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1354 (Elf_Addr) &r_debug; 1355 break; 1356 1357 case DT_MIPS_PLTGOT: 1358 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1359 dynp->d_un.d_ptr); 1360 break; 1361 1362 #endif 1363 1364 #ifdef __powerpc__ 1365 #ifdef __powerpc64__ 1366 case DT_PPC64_GLINK: 1367 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1368 break; 1369 #else 1370 case DT_PPC_GOT: 1371 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1372 break; 1373 #endif 1374 #endif 1375 1376 case DT_FLAGS_1: 1377 if (dynp->d_un.d_val & DF_1_NOOPEN) 1378 obj->z_noopen = true; 1379 if (dynp->d_un.d_val & DF_1_ORIGIN) 1380 obj->z_origin = true; 1381 if (dynp->d_un.d_val & DF_1_GLOBAL) 1382 obj->z_global = true; 1383 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1384 obj->bind_now = true; 1385 if (dynp->d_un.d_val & DF_1_NODELETE) 1386 obj->z_nodelete = true; 1387 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1388 obj->z_loadfltr = true; 1389 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1390 obj->z_interpose = true; 1391 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1392 obj->z_nodeflib = true; 1393 if (dynp->d_un.d_val & DF_1_PIE) 1394 obj->z_pie = true; 1395 break; 1396 1397 default: 1398 if (!early) { 1399 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1400 (long)dynp->d_tag); 1401 } 1402 break; 1403 } 1404 } 1405 1406 obj->traced = false; 1407 1408 if (plttype == DT_RELA) { 1409 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1410 obj->pltrel = NULL; 1411 obj->pltrelasize = obj->pltrelsize; 1412 obj->pltrelsize = 0; 1413 } 1414 1415 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1416 if (obj->valid_hash_sysv) 1417 obj->dynsymcount = obj->nchains; 1418 else if (obj->valid_hash_gnu) { 1419 obj->dynsymcount = 0; 1420 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1421 if (obj->buckets_gnu[bkt] == 0) 1422 continue; 1423 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1424 do 1425 obj->dynsymcount++; 1426 while ((*hashval++ & 1u) == 0); 1427 } 1428 obj->dynsymcount += obj->symndx_gnu; 1429 } 1430 1431 if (obj->linkmap.l_refname != NULL) 1432 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1433 linkmap.l_refname; 1434 } 1435 1436 static bool 1437 obj_resolve_origin(Obj_Entry *obj) 1438 { 1439 1440 if (obj->origin_path != NULL) 1441 return (true); 1442 obj->origin_path = xmalloc(PATH_MAX); 1443 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1444 } 1445 1446 static bool 1447 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1448 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1449 { 1450 1451 if (obj->z_origin && !obj_resolve_origin(obj)) 1452 return (false); 1453 1454 if (dyn_runpath != NULL) { 1455 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1456 obj->runpath = origin_subst(obj, obj->runpath); 1457 } else if (dyn_rpath != NULL) { 1458 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1459 obj->rpath = origin_subst(obj, obj->rpath); 1460 } 1461 if (dyn_soname != NULL) 1462 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1463 return (true); 1464 } 1465 1466 static bool 1467 digest_dynamic(Obj_Entry *obj, int early) 1468 { 1469 const Elf_Dyn *dyn_rpath; 1470 const Elf_Dyn *dyn_soname; 1471 const Elf_Dyn *dyn_runpath; 1472 1473 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1474 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1475 } 1476 1477 /* 1478 * Process a shared object's program header. This is used only for the 1479 * main program, when the kernel has already loaded the main program 1480 * into memory before calling the dynamic linker. It creates and 1481 * returns an Obj_Entry structure. 1482 */ 1483 static Obj_Entry * 1484 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1485 { 1486 Obj_Entry *obj; 1487 const Elf_Phdr *phlimit = phdr + phnum; 1488 const Elf_Phdr *ph; 1489 Elf_Addr note_start, note_end; 1490 int nsegs = 0; 1491 1492 obj = obj_new(); 1493 for (ph = phdr; ph < phlimit; ph++) { 1494 if (ph->p_type != PT_PHDR) 1495 continue; 1496 1497 obj->phdr = phdr; 1498 obj->phsize = ph->p_memsz; 1499 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1500 break; 1501 } 1502 1503 obj->stack_flags = PF_X | PF_R | PF_W; 1504 1505 for (ph = phdr; ph < phlimit; ph++) { 1506 switch (ph->p_type) { 1507 1508 case PT_INTERP: 1509 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1510 break; 1511 1512 case PT_LOAD: 1513 if (nsegs == 0) { /* First load segment */ 1514 obj->vaddrbase = trunc_page(ph->p_vaddr); 1515 obj->mapbase = obj->vaddrbase + obj->relocbase; 1516 } else { /* Last load segment */ 1517 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1518 obj->vaddrbase; 1519 } 1520 nsegs++; 1521 break; 1522 1523 case PT_DYNAMIC: 1524 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1525 break; 1526 1527 case PT_TLS: 1528 obj->tlsindex = 1; 1529 obj->tlssize = ph->p_memsz; 1530 obj->tlsalign = ph->p_align; 1531 obj->tlsinitsize = ph->p_filesz; 1532 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1533 obj->tlspoffset = ph->p_offset; 1534 break; 1535 1536 case PT_GNU_STACK: 1537 obj->stack_flags = ph->p_flags; 1538 break; 1539 1540 case PT_GNU_RELRO: 1541 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1542 obj->relro_size = round_page(ph->p_memsz); 1543 break; 1544 1545 case PT_NOTE: 1546 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1547 note_end = note_start + ph->p_filesz; 1548 digest_notes(obj, note_start, note_end); 1549 break; 1550 } 1551 } 1552 if (nsegs < 1) { 1553 _rtld_error("%s: too few PT_LOAD segments", path); 1554 return NULL; 1555 } 1556 1557 obj->entry = entry; 1558 return obj; 1559 } 1560 1561 void 1562 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1563 { 1564 const Elf_Note *note; 1565 const char *note_name; 1566 uintptr_t p; 1567 1568 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1569 note = (const Elf_Note *)((const char *)(note + 1) + 1570 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1571 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1572 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1573 note->n_descsz != sizeof(int32_t)) 1574 continue; 1575 if (note->n_type != NT_FREEBSD_ABI_TAG && 1576 note->n_type != NT_FREEBSD_FEATURE_CTL && 1577 note->n_type != NT_FREEBSD_NOINIT_TAG) 1578 continue; 1579 note_name = (const char *)(note + 1); 1580 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1581 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1582 continue; 1583 switch (note->n_type) { 1584 case NT_FREEBSD_ABI_TAG: 1585 /* FreeBSD osrel note */ 1586 p = (uintptr_t)(note + 1); 1587 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1588 obj->osrel = *(const int32_t *)(p); 1589 dbg("note osrel %d", obj->osrel); 1590 break; 1591 case NT_FREEBSD_FEATURE_CTL: 1592 /* FreeBSD ABI feature control note */ 1593 p = (uintptr_t)(note + 1); 1594 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1595 obj->fctl0 = *(const uint32_t *)(p); 1596 dbg("note fctl0 %#x", obj->fctl0); 1597 break; 1598 case NT_FREEBSD_NOINIT_TAG: 1599 /* FreeBSD 'crt does not call init' note */ 1600 obj->crt_no_init = true; 1601 dbg("note crt_no_init"); 1602 break; 1603 } 1604 } 1605 } 1606 1607 static Obj_Entry * 1608 dlcheck(void *handle) 1609 { 1610 Obj_Entry *obj; 1611 1612 TAILQ_FOREACH(obj, &obj_list, next) { 1613 if (obj == (Obj_Entry *) handle) 1614 break; 1615 } 1616 1617 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1618 _rtld_error("Invalid shared object handle %p", handle); 1619 return NULL; 1620 } 1621 return obj; 1622 } 1623 1624 /* 1625 * If the given object is already in the donelist, return true. Otherwise 1626 * add the object to the list and return false. 1627 */ 1628 static bool 1629 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1630 { 1631 unsigned int i; 1632 1633 for (i = 0; i < dlp->num_used; i++) 1634 if (dlp->objs[i] == obj) 1635 return true; 1636 /* 1637 * Our donelist allocation should always be sufficient. But if 1638 * our threads locking isn't working properly, more shared objects 1639 * could have been loaded since we allocated the list. That should 1640 * never happen, but we'll handle it properly just in case it does. 1641 */ 1642 if (dlp->num_used < dlp->num_alloc) 1643 dlp->objs[dlp->num_used++] = obj; 1644 return false; 1645 } 1646 1647 /* 1648 * Hash function for symbol table lookup. Don't even think about changing 1649 * this. It is specified by the System V ABI. 1650 */ 1651 unsigned long 1652 elf_hash(const char *name) 1653 { 1654 const unsigned char *p = (const unsigned char *) name; 1655 unsigned long h = 0; 1656 unsigned long g; 1657 1658 while (*p != '\0') { 1659 h = (h << 4) + *p++; 1660 if ((g = h & 0xf0000000) != 0) 1661 h ^= g >> 24; 1662 h &= ~g; 1663 } 1664 return h; 1665 } 1666 1667 /* 1668 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1669 * unsigned in case it's implemented with a wider type. 1670 */ 1671 static uint32_t 1672 gnu_hash(const char *s) 1673 { 1674 uint32_t h; 1675 unsigned char c; 1676 1677 h = 5381; 1678 for (c = *s; c != '\0'; c = *++s) 1679 h = h * 33 + c; 1680 return (h & 0xffffffff); 1681 } 1682 1683 1684 /* 1685 * Find the library with the given name, and return its full pathname. 1686 * The returned string is dynamically allocated. Generates an error 1687 * message and returns NULL if the library cannot be found. 1688 * 1689 * If the second argument is non-NULL, then it refers to an already- 1690 * loaded shared object, whose library search path will be searched. 1691 * 1692 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1693 * descriptor (which is close-on-exec) will be passed out via the third 1694 * argument. 1695 * 1696 * The search order is: 1697 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1698 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1699 * LD_LIBRARY_PATH 1700 * DT_RUNPATH in the referencing file 1701 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1702 * from list) 1703 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1704 * 1705 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1706 */ 1707 static char * 1708 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1709 { 1710 char *pathname, *refobj_path; 1711 const char *name; 1712 bool nodeflib, objgiven; 1713 1714 objgiven = refobj != NULL; 1715 1716 if (libmap_disable || !objgiven || 1717 (name = lm_find(refobj->path, xname)) == NULL) 1718 name = xname; 1719 1720 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1721 if (name[0] != '/' && !trust) { 1722 _rtld_error("Absolute pathname required " 1723 "for shared object \"%s\"", name); 1724 return (NULL); 1725 } 1726 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1727 __DECONST(char *, name))); 1728 } 1729 1730 dbg(" Searching for \"%s\"", name); 1731 refobj_path = objgiven ? refobj->path : NULL; 1732 1733 /* 1734 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1735 * back to pre-conforming behaviour if user requested so with 1736 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1737 * nodeflib. 1738 */ 1739 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1740 pathname = search_library_path(name, ld_library_path, 1741 refobj_path, fdp); 1742 if (pathname != NULL) 1743 return (pathname); 1744 if (refobj != NULL) { 1745 pathname = search_library_path(name, refobj->rpath, 1746 refobj_path, fdp); 1747 if (pathname != NULL) 1748 return (pathname); 1749 } 1750 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1751 if (pathname != NULL) 1752 return (pathname); 1753 pathname = search_library_path(name, gethints(false), 1754 refobj_path, fdp); 1755 if (pathname != NULL) 1756 return (pathname); 1757 pathname = search_library_path(name, ld_standard_library_path, 1758 refobj_path, fdp); 1759 if (pathname != NULL) 1760 return (pathname); 1761 } else { 1762 nodeflib = objgiven ? refobj->z_nodeflib : false; 1763 if (objgiven) { 1764 pathname = search_library_path(name, refobj->rpath, 1765 refobj->path, fdp); 1766 if (pathname != NULL) 1767 return (pathname); 1768 } 1769 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1770 pathname = search_library_path(name, obj_main->rpath, 1771 refobj_path, fdp); 1772 if (pathname != NULL) 1773 return (pathname); 1774 } 1775 pathname = search_library_path(name, ld_library_path, 1776 refobj_path, fdp); 1777 if (pathname != NULL) 1778 return (pathname); 1779 if (objgiven) { 1780 pathname = search_library_path(name, refobj->runpath, 1781 refobj_path, fdp); 1782 if (pathname != NULL) 1783 return (pathname); 1784 } 1785 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1786 if (pathname != NULL) 1787 return (pathname); 1788 pathname = search_library_path(name, gethints(nodeflib), 1789 refobj_path, fdp); 1790 if (pathname != NULL) 1791 return (pathname); 1792 if (objgiven && !nodeflib) { 1793 pathname = search_library_path(name, 1794 ld_standard_library_path, refobj_path, fdp); 1795 if (pathname != NULL) 1796 return (pathname); 1797 } 1798 } 1799 1800 if (objgiven && refobj->path != NULL) { 1801 _rtld_error("Shared object \"%s\" not found, " 1802 "required by \"%s\"", name, basename(refobj->path)); 1803 } else { 1804 _rtld_error("Shared object \"%s\" not found", name); 1805 } 1806 return (NULL); 1807 } 1808 1809 /* 1810 * Given a symbol number in a referencing object, find the corresponding 1811 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1812 * no definition was found. Returns a pointer to the Obj_Entry of the 1813 * defining object via the reference parameter DEFOBJ_OUT. 1814 */ 1815 const Elf_Sym * 1816 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1817 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1818 RtldLockState *lockstate) 1819 { 1820 const Elf_Sym *ref; 1821 const Elf_Sym *def; 1822 const Obj_Entry *defobj; 1823 const Ver_Entry *ve; 1824 SymLook req; 1825 const char *name; 1826 int res; 1827 1828 /* 1829 * If we have already found this symbol, get the information from 1830 * the cache. 1831 */ 1832 if (symnum >= refobj->dynsymcount) 1833 return NULL; /* Bad object */ 1834 if (cache != NULL && cache[symnum].sym != NULL) { 1835 *defobj_out = cache[symnum].obj; 1836 return cache[symnum].sym; 1837 } 1838 1839 ref = refobj->symtab + symnum; 1840 name = refobj->strtab + ref->st_name; 1841 def = NULL; 1842 defobj = NULL; 1843 ve = NULL; 1844 1845 /* 1846 * We don't have to do a full scale lookup if the symbol is local. 1847 * We know it will bind to the instance in this load module; to 1848 * which we already have a pointer (ie ref). By not doing a lookup, 1849 * we not only improve performance, but it also avoids unresolvable 1850 * symbols when local symbols are not in the hash table. This has 1851 * been seen with the ia64 toolchain. 1852 */ 1853 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1854 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1855 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1856 symnum); 1857 } 1858 symlook_init(&req, name); 1859 req.flags = flags; 1860 ve = req.ventry = fetch_ventry(refobj, symnum); 1861 req.lockstate = lockstate; 1862 res = symlook_default(&req, refobj); 1863 if (res == 0) { 1864 def = req.sym_out; 1865 defobj = req.defobj_out; 1866 } 1867 } else { 1868 def = ref; 1869 defobj = refobj; 1870 } 1871 1872 /* 1873 * If we found no definition and the reference is weak, treat the 1874 * symbol as having the value zero. 1875 */ 1876 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1877 def = &sym_zero; 1878 defobj = obj_main; 1879 } 1880 1881 if (def != NULL) { 1882 *defobj_out = defobj; 1883 /* Record the information in the cache to avoid subsequent lookups. */ 1884 if (cache != NULL) { 1885 cache[symnum].sym = def; 1886 cache[symnum].obj = defobj; 1887 } 1888 } else { 1889 if (refobj != &obj_rtld) 1890 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1891 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1892 } 1893 return def; 1894 } 1895 1896 /* 1897 * Return the search path from the ldconfig hints file, reading it if 1898 * necessary. If nostdlib is true, then the default search paths are 1899 * not added to result. 1900 * 1901 * Returns NULL if there are problems with the hints file, 1902 * or if the search path there is empty. 1903 */ 1904 static const char * 1905 gethints(bool nostdlib) 1906 { 1907 static char *filtered_path; 1908 static const char *hints; 1909 static struct elfhints_hdr hdr; 1910 struct fill_search_info_args sargs, hargs; 1911 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1912 struct dl_serpath *SLPpath, *hintpath; 1913 char *p; 1914 struct stat hint_stat; 1915 unsigned int SLPndx, hintndx, fndx, fcount; 1916 int fd; 1917 size_t flen; 1918 uint32_t dl; 1919 bool skip; 1920 1921 /* First call, read the hints file */ 1922 if (hints == NULL) { 1923 /* Keep from trying again in case the hints file is bad. */ 1924 hints = ""; 1925 1926 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1927 return (NULL); 1928 1929 /* 1930 * Check of hdr.dirlistlen value against type limit 1931 * intends to pacify static analyzers. Further 1932 * paranoia leads to checks that dirlist is fully 1933 * contained in the file range. 1934 */ 1935 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1936 hdr.magic != ELFHINTS_MAGIC || 1937 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1938 fstat(fd, &hint_stat) == -1) { 1939 cleanup1: 1940 close(fd); 1941 hdr.dirlistlen = 0; 1942 return (NULL); 1943 } 1944 dl = hdr.strtab; 1945 if (dl + hdr.dirlist < dl) 1946 goto cleanup1; 1947 dl += hdr.dirlist; 1948 if (dl + hdr.dirlistlen < dl) 1949 goto cleanup1; 1950 dl += hdr.dirlistlen; 1951 if (dl > hint_stat.st_size) 1952 goto cleanup1; 1953 p = xmalloc(hdr.dirlistlen + 1); 1954 if (pread(fd, p, hdr.dirlistlen + 1, 1955 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1956 p[hdr.dirlistlen] != '\0') { 1957 free(p); 1958 goto cleanup1; 1959 } 1960 hints = p; 1961 close(fd); 1962 } 1963 1964 /* 1965 * If caller agreed to receive list which includes the default 1966 * paths, we are done. Otherwise, if we still did not 1967 * calculated filtered result, do it now. 1968 */ 1969 if (!nostdlib) 1970 return (hints[0] != '\0' ? hints : NULL); 1971 if (filtered_path != NULL) 1972 goto filt_ret; 1973 1974 /* 1975 * Obtain the list of all configured search paths, and the 1976 * list of the default paths. 1977 * 1978 * First estimate the size of the results. 1979 */ 1980 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1981 smeta.dls_cnt = 0; 1982 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1983 hmeta.dls_cnt = 0; 1984 1985 sargs.request = RTLD_DI_SERINFOSIZE; 1986 sargs.serinfo = &smeta; 1987 hargs.request = RTLD_DI_SERINFOSIZE; 1988 hargs.serinfo = &hmeta; 1989 1990 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1991 &sargs); 1992 path_enumerate(hints, fill_search_info, NULL, &hargs); 1993 1994 SLPinfo = xmalloc(smeta.dls_size); 1995 hintinfo = xmalloc(hmeta.dls_size); 1996 1997 /* 1998 * Next fetch both sets of paths. 1999 */ 2000 sargs.request = RTLD_DI_SERINFO; 2001 sargs.serinfo = SLPinfo; 2002 sargs.serpath = &SLPinfo->dls_serpath[0]; 2003 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2004 2005 hargs.request = RTLD_DI_SERINFO; 2006 hargs.serinfo = hintinfo; 2007 hargs.serpath = &hintinfo->dls_serpath[0]; 2008 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2009 2010 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2011 &sargs); 2012 path_enumerate(hints, fill_search_info, NULL, &hargs); 2013 2014 /* 2015 * Now calculate the difference between two sets, by excluding 2016 * standard paths from the full set. 2017 */ 2018 fndx = 0; 2019 fcount = 0; 2020 filtered_path = xmalloc(hdr.dirlistlen + 1); 2021 hintpath = &hintinfo->dls_serpath[0]; 2022 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2023 skip = false; 2024 SLPpath = &SLPinfo->dls_serpath[0]; 2025 /* 2026 * Check each standard path against current. 2027 */ 2028 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2029 /* matched, skip the path */ 2030 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2031 skip = true; 2032 break; 2033 } 2034 } 2035 if (skip) 2036 continue; 2037 /* 2038 * Not matched against any standard path, add the path 2039 * to result. Separate consequtive paths with ':'. 2040 */ 2041 if (fcount > 0) { 2042 filtered_path[fndx] = ':'; 2043 fndx++; 2044 } 2045 fcount++; 2046 flen = strlen(hintpath->dls_name); 2047 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2048 fndx += flen; 2049 } 2050 filtered_path[fndx] = '\0'; 2051 2052 free(SLPinfo); 2053 free(hintinfo); 2054 2055 filt_ret: 2056 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2057 } 2058 2059 static void 2060 init_dag(Obj_Entry *root) 2061 { 2062 const Needed_Entry *needed; 2063 const Objlist_Entry *elm; 2064 DoneList donelist; 2065 2066 if (root->dag_inited) 2067 return; 2068 donelist_init(&donelist); 2069 2070 /* Root object belongs to own DAG. */ 2071 objlist_push_tail(&root->dldags, root); 2072 objlist_push_tail(&root->dagmembers, root); 2073 donelist_check(&donelist, root); 2074 2075 /* 2076 * Add dependencies of root object to DAG in breadth order 2077 * by exploiting the fact that each new object get added 2078 * to the tail of the dagmembers list. 2079 */ 2080 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2081 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2082 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2083 continue; 2084 objlist_push_tail(&needed->obj->dldags, root); 2085 objlist_push_tail(&root->dagmembers, needed->obj); 2086 } 2087 } 2088 root->dag_inited = true; 2089 } 2090 2091 static void 2092 init_marker(Obj_Entry *marker) 2093 { 2094 2095 bzero(marker, sizeof(*marker)); 2096 marker->marker = true; 2097 } 2098 2099 Obj_Entry * 2100 globallist_curr(const Obj_Entry *obj) 2101 { 2102 2103 for (;;) { 2104 if (obj == NULL) 2105 return (NULL); 2106 if (!obj->marker) 2107 return (__DECONST(Obj_Entry *, obj)); 2108 obj = TAILQ_PREV(obj, obj_entry_q, next); 2109 } 2110 } 2111 2112 Obj_Entry * 2113 globallist_next(const Obj_Entry *obj) 2114 { 2115 2116 for (;;) { 2117 obj = TAILQ_NEXT(obj, next); 2118 if (obj == NULL) 2119 return (NULL); 2120 if (!obj->marker) 2121 return (__DECONST(Obj_Entry *, obj)); 2122 } 2123 } 2124 2125 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2126 static void 2127 hold_object(Obj_Entry *obj) 2128 { 2129 2130 obj->holdcount++; 2131 } 2132 2133 static void 2134 unhold_object(Obj_Entry *obj) 2135 { 2136 2137 assert(obj->holdcount > 0); 2138 if (--obj->holdcount == 0 && obj->unholdfree) 2139 release_object(obj); 2140 } 2141 2142 static void 2143 process_z(Obj_Entry *root) 2144 { 2145 const Objlist_Entry *elm; 2146 Obj_Entry *obj; 2147 2148 /* 2149 * Walk over object DAG and process every dependent object 2150 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2151 * to grow their own DAG. 2152 * 2153 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2154 * symlook_global() to work. 2155 * 2156 * For DF_1_NODELETE, the DAG should have its reference upped. 2157 */ 2158 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2159 obj = elm->obj; 2160 if (obj == NULL) 2161 continue; 2162 if (obj->z_nodelete && !obj->ref_nodel) { 2163 dbg("obj %s -z nodelete", obj->path); 2164 init_dag(obj); 2165 ref_dag(obj); 2166 obj->ref_nodel = true; 2167 } 2168 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2169 dbg("obj %s -z global", obj->path); 2170 objlist_push_tail(&list_global, obj); 2171 init_dag(obj); 2172 } 2173 } 2174 } 2175 2176 static void 2177 parse_rtld_phdr(Obj_Entry *obj) 2178 { 2179 const Elf_Phdr *ph; 2180 Elf_Addr note_start, note_end; 2181 2182 obj->stack_flags = PF_X | PF_R | PF_W; 2183 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2184 obj->phsize; ph++) { 2185 switch (ph->p_type) { 2186 case PT_GNU_STACK: 2187 obj->stack_flags = ph->p_flags; 2188 break; 2189 case PT_GNU_RELRO: 2190 obj->relro_page = obj->relocbase + 2191 trunc_page(ph->p_vaddr); 2192 obj->relro_size = round_page(ph->p_memsz); 2193 break; 2194 case PT_NOTE: 2195 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2196 note_end = note_start + ph->p_filesz; 2197 digest_notes(obj, note_start, note_end); 2198 break; 2199 } 2200 } 2201 } 2202 2203 /* 2204 * Initialize the dynamic linker. The argument is the address at which 2205 * the dynamic linker has been mapped into memory. The primary task of 2206 * this function is to relocate the dynamic linker. 2207 */ 2208 static void 2209 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2210 { 2211 Obj_Entry objtmp; /* Temporary rtld object */ 2212 const Elf_Ehdr *ehdr; 2213 const Elf_Dyn *dyn_rpath; 2214 const Elf_Dyn *dyn_soname; 2215 const Elf_Dyn *dyn_runpath; 2216 2217 #ifdef RTLD_INIT_PAGESIZES_EARLY 2218 /* The page size is required by the dynamic memory allocator. */ 2219 init_pagesizes(aux_info); 2220 #endif 2221 2222 /* 2223 * Conjure up an Obj_Entry structure for the dynamic linker. 2224 * 2225 * The "path" member can't be initialized yet because string constants 2226 * cannot yet be accessed. Below we will set it correctly. 2227 */ 2228 memset(&objtmp, 0, sizeof(objtmp)); 2229 objtmp.path = NULL; 2230 objtmp.rtld = true; 2231 objtmp.mapbase = mapbase; 2232 #ifdef PIC 2233 objtmp.relocbase = mapbase; 2234 #endif 2235 2236 objtmp.dynamic = rtld_dynamic(&objtmp); 2237 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2238 assert(objtmp.needed == NULL); 2239 #if !defined(__mips__) 2240 /* MIPS has a bogus DT_TEXTREL. */ 2241 assert(!objtmp.textrel); 2242 #endif 2243 /* 2244 * Temporarily put the dynamic linker entry into the object list, so 2245 * that symbols can be found. 2246 */ 2247 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2248 2249 ehdr = (Elf_Ehdr *)mapbase; 2250 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2251 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2252 2253 /* Initialize the object list. */ 2254 TAILQ_INIT(&obj_list); 2255 2256 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2257 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2258 2259 #ifndef RTLD_INIT_PAGESIZES_EARLY 2260 /* The page size is required by the dynamic memory allocator. */ 2261 init_pagesizes(aux_info); 2262 #endif 2263 2264 if (aux_info[AT_OSRELDATE] != NULL) 2265 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2266 2267 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2268 2269 /* Replace the path with a dynamically allocated copy. */ 2270 obj_rtld.path = xstrdup(ld_path_rtld); 2271 2272 parse_rtld_phdr(&obj_rtld); 2273 obj_enforce_relro(&obj_rtld); 2274 2275 r_debug.r_brk = r_debug_state; 2276 r_debug.r_state = RT_CONSISTENT; 2277 } 2278 2279 /* 2280 * Retrieve the array of supported page sizes. The kernel provides the page 2281 * sizes in increasing order. 2282 */ 2283 static void 2284 init_pagesizes(Elf_Auxinfo **aux_info) 2285 { 2286 static size_t psa[MAXPAGESIZES]; 2287 int mib[2]; 2288 size_t len, size; 2289 2290 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2291 NULL) { 2292 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2293 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2294 } else { 2295 len = 2; 2296 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2297 size = sizeof(psa); 2298 else { 2299 /* As a fallback, retrieve the base page size. */ 2300 size = sizeof(psa[0]); 2301 if (aux_info[AT_PAGESZ] != NULL) { 2302 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2303 goto psa_filled; 2304 } else { 2305 mib[0] = CTL_HW; 2306 mib[1] = HW_PAGESIZE; 2307 len = 2; 2308 } 2309 } 2310 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2311 _rtld_error("sysctl for hw.pagesize(s) failed"); 2312 rtld_die(); 2313 } 2314 psa_filled: 2315 pagesizes = psa; 2316 } 2317 npagesizes = size / sizeof(pagesizes[0]); 2318 /* Discard any invalid entries at the end of the array. */ 2319 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2320 npagesizes--; 2321 } 2322 2323 /* 2324 * Add the init functions from a needed object list (and its recursive 2325 * needed objects) to "list". This is not used directly; it is a helper 2326 * function for initlist_add_objects(). The write lock must be held 2327 * when this function is called. 2328 */ 2329 static void 2330 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2331 { 2332 /* Recursively process the successor needed objects. */ 2333 if (needed->next != NULL) 2334 initlist_add_neededs(needed->next, list); 2335 2336 /* Process the current needed object. */ 2337 if (needed->obj != NULL) 2338 initlist_add_objects(needed->obj, needed->obj, list); 2339 } 2340 2341 /* 2342 * Scan all of the DAGs rooted in the range of objects from "obj" to 2343 * "tail" and add their init functions to "list". This recurses over 2344 * the DAGs and ensure the proper init ordering such that each object's 2345 * needed libraries are initialized before the object itself. At the 2346 * same time, this function adds the objects to the global finalization 2347 * list "list_fini" in the opposite order. The write lock must be 2348 * held when this function is called. 2349 */ 2350 static void 2351 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2352 { 2353 Obj_Entry *nobj; 2354 2355 if (obj->init_scanned || obj->init_done) 2356 return; 2357 obj->init_scanned = true; 2358 2359 /* Recursively process the successor objects. */ 2360 nobj = globallist_next(obj); 2361 if (nobj != NULL && obj != tail) 2362 initlist_add_objects(nobj, tail, list); 2363 2364 /* Recursively process the needed objects. */ 2365 if (obj->needed != NULL) 2366 initlist_add_neededs(obj->needed, list); 2367 if (obj->needed_filtees != NULL) 2368 initlist_add_neededs(obj->needed_filtees, list); 2369 if (obj->needed_aux_filtees != NULL) 2370 initlist_add_neededs(obj->needed_aux_filtees, list); 2371 2372 /* Add the object to the init list. */ 2373 objlist_push_tail(list, obj); 2374 2375 /* Add the object to the global fini list in the reverse order. */ 2376 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2377 && !obj->on_fini_list) { 2378 objlist_push_head(&list_fini, obj); 2379 obj->on_fini_list = true; 2380 } 2381 } 2382 2383 #ifndef FPTR_TARGET 2384 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2385 #endif 2386 2387 static void 2388 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2389 { 2390 Needed_Entry *needed, *needed1; 2391 2392 for (needed = n; needed != NULL; needed = needed->next) { 2393 if (needed->obj != NULL) { 2394 dlclose_locked(needed->obj, lockstate); 2395 needed->obj = NULL; 2396 } 2397 } 2398 for (needed = n; needed != NULL; needed = needed1) { 2399 needed1 = needed->next; 2400 free(needed); 2401 } 2402 } 2403 2404 static void 2405 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2406 { 2407 2408 free_needed_filtees(obj->needed_filtees, lockstate); 2409 obj->needed_filtees = NULL; 2410 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2411 obj->needed_aux_filtees = NULL; 2412 obj->filtees_loaded = false; 2413 } 2414 2415 static void 2416 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2417 RtldLockState *lockstate) 2418 { 2419 2420 for (; needed != NULL; needed = needed->next) { 2421 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2422 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2423 RTLD_LOCAL, lockstate); 2424 } 2425 } 2426 2427 static void 2428 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2429 { 2430 2431 lock_restart_for_upgrade(lockstate); 2432 if (!obj->filtees_loaded) { 2433 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2434 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2435 obj->filtees_loaded = true; 2436 } 2437 } 2438 2439 static int 2440 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2441 { 2442 Obj_Entry *obj1; 2443 2444 for (; needed != NULL; needed = needed->next) { 2445 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2446 flags & ~RTLD_LO_NOLOAD); 2447 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2448 return (-1); 2449 } 2450 return (0); 2451 } 2452 2453 /* 2454 * Given a shared object, traverse its list of needed objects, and load 2455 * each of them. Returns 0 on success. Generates an error message and 2456 * returns -1 on failure. 2457 */ 2458 static int 2459 load_needed_objects(Obj_Entry *first, int flags) 2460 { 2461 Obj_Entry *obj; 2462 2463 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2464 if (obj->marker) 2465 continue; 2466 if (process_needed(obj, obj->needed, flags) == -1) 2467 return (-1); 2468 } 2469 return (0); 2470 } 2471 2472 static int 2473 load_preload_objects(void) 2474 { 2475 char *p = ld_preload; 2476 Obj_Entry *obj; 2477 static const char delim[] = " \t:;"; 2478 2479 if (p == NULL) 2480 return 0; 2481 2482 p += strspn(p, delim); 2483 while (*p != '\0') { 2484 size_t len = strcspn(p, delim); 2485 char savech; 2486 2487 savech = p[len]; 2488 p[len] = '\0'; 2489 obj = load_object(p, -1, NULL, 0); 2490 if (obj == NULL) 2491 return -1; /* XXX - cleanup */ 2492 obj->z_interpose = true; 2493 p[len] = savech; 2494 p += len; 2495 p += strspn(p, delim); 2496 } 2497 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2498 return 0; 2499 } 2500 2501 static const char * 2502 printable_path(const char *path) 2503 { 2504 2505 return (path == NULL ? "<unknown>" : path); 2506 } 2507 2508 /* 2509 * Load a shared object into memory, if it is not already loaded. The 2510 * object may be specified by name or by user-supplied file descriptor 2511 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2512 * duplicate is. 2513 * 2514 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2515 * on failure. 2516 */ 2517 static Obj_Entry * 2518 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2519 { 2520 Obj_Entry *obj; 2521 int fd; 2522 struct stat sb; 2523 char *path; 2524 2525 fd = -1; 2526 if (name != NULL) { 2527 TAILQ_FOREACH(obj, &obj_list, next) { 2528 if (obj->marker || obj->doomed) 2529 continue; 2530 if (object_match_name(obj, name)) 2531 return (obj); 2532 } 2533 2534 path = find_library(name, refobj, &fd); 2535 if (path == NULL) 2536 return (NULL); 2537 } else 2538 path = NULL; 2539 2540 if (fd >= 0) { 2541 /* 2542 * search_library_pathfds() opens a fresh file descriptor for the 2543 * library, so there is no need to dup(). 2544 */ 2545 } else if (fd_u == -1) { 2546 /* 2547 * If we didn't find a match by pathname, or the name is not 2548 * supplied, open the file and check again by device and inode. 2549 * This avoids false mismatches caused by multiple links or ".." 2550 * in pathnames. 2551 * 2552 * To avoid a race, we open the file and use fstat() rather than 2553 * using stat(). 2554 */ 2555 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2556 _rtld_error("Cannot open \"%s\"", path); 2557 free(path); 2558 return (NULL); 2559 } 2560 } else { 2561 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2562 if (fd == -1) { 2563 _rtld_error("Cannot dup fd"); 2564 free(path); 2565 return (NULL); 2566 } 2567 } 2568 if (fstat(fd, &sb) == -1) { 2569 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2570 close(fd); 2571 free(path); 2572 return NULL; 2573 } 2574 TAILQ_FOREACH(obj, &obj_list, next) { 2575 if (obj->marker || obj->doomed) 2576 continue; 2577 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2578 break; 2579 } 2580 if (obj != NULL && name != NULL) { 2581 object_add_name(obj, name); 2582 free(path); 2583 close(fd); 2584 return obj; 2585 } 2586 if (flags & RTLD_LO_NOLOAD) { 2587 free(path); 2588 close(fd); 2589 return (NULL); 2590 } 2591 2592 /* First use of this object, so we must map it in */ 2593 obj = do_load_object(fd, name, path, &sb, flags); 2594 if (obj == NULL) 2595 free(path); 2596 close(fd); 2597 2598 return obj; 2599 } 2600 2601 static Obj_Entry * 2602 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2603 int flags) 2604 { 2605 Obj_Entry *obj; 2606 struct statfs fs; 2607 2608 /* 2609 * but first, make sure that environment variables haven't been 2610 * used to circumvent the noexec flag on a filesystem. 2611 */ 2612 if (dangerous_ld_env) { 2613 if (fstatfs(fd, &fs) != 0) { 2614 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2615 return NULL; 2616 } 2617 if (fs.f_flags & MNT_NOEXEC) { 2618 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2619 return NULL; 2620 } 2621 } 2622 dbg("loading \"%s\"", printable_path(path)); 2623 obj = map_object(fd, printable_path(path), sbp); 2624 if (obj == NULL) 2625 return NULL; 2626 2627 /* 2628 * If DT_SONAME is present in the object, digest_dynamic2 already 2629 * added it to the object names. 2630 */ 2631 if (name != NULL) 2632 object_add_name(obj, name); 2633 obj->path = path; 2634 if (!digest_dynamic(obj, 0)) 2635 goto errp; 2636 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2637 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2638 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2639 dbg("refusing to load PIE executable \"%s\"", obj->path); 2640 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2641 goto errp; 2642 } 2643 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2644 RTLD_LO_DLOPEN) { 2645 dbg("refusing to load non-loadable \"%s\"", obj->path); 2646 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2647 goto errp; 2648 } 2649 2650 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2651 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2652 obj_count++; 2653 obj_loads++; 2654 linkmap_add(obj); /* for GDB & dlinfo() */ 2655 max_stack_flags |= obj->stack_flags; 2656 2657 dbg(" %p .. %p: %s", obj->mapbase, 2658 obj->mapbase + obj->mapsize - 1, obj->path); 2659 if (obj->textrel) 2660 dbg(" WARNING: %s has impure text", obj->path); 2661 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2662 obj->path); 2663 2664 return (obj); 2665 2666 errp: 2667 munmap(obj->mapbase, obj->mapsize); 2668 obj_free(obj); 2669 return (NULL); 2670 } 2671 2672 static Obj_Entry * 2673 obj_from_addr(const void *addr) 2674 { 2675 Obj_Entry *obj; 2676 2677 TAILQ_FOREACH(obj, &obj_list, next) { 2678 if (obj->marker) 2679 continue; 2680 if (addr < (void *) obj->mapbase) 2681 continue; 2682 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2683 return obj; 2684 } 2685 return NULL; 2686 } 2687 2688 static void 2689 preinit_main(void) 2690 { 2691 Elf_Addr *preinit_addr; 2692 int index; 2693 2694 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2695 if (preinit_addr == NULL) 2696 return; 2697 2698 for (index = 0; index < obj_main->preinit_array_num; index++) { 2699 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2700 dbg("calling preinit function for %s at %p", obj_main->path, 2701 (void *)preinit_addr[index]); 2702 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2703 0, 0, obj_main->path); 2704 call_init_pointer(obj_main, preinit_addr[index]); 2705 } 2706 } 2707 } 2708 2709 /* 2710 * Call the finalization functions for each of the objects in "list" 2711 * belonging to the DAG of "root" and referenced once. If NULL "root" 2712 * is specified, every finalization function will be called regardless 2713 * of the reference count and the list elements won't be freed. All of 2714 * the objects are expected to have non-NULL fini functions. 2715 */ 2716 static void 2717 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2718 { 2719 Objlist_Entry *elm; 2720 char *saved_msg; 2721 Elf_Addr *fini_addr; 2722 int index; 2723 2724 assert(root == NULL || root->refcount == 1); 2725 2726 if (root != NULL) 2727 root->doomed = true; 2728 2729 /* 2730 * Preserve the current error message since a fini function might 2731 * call into the dynamic linker and overwrite it. 2732 */ 2733 saved_msg = errmsg_save(); 2734 do { 2735 STAILQ_FOREACH(elm, list, link) { 2736 if (root != NULL && (elm->obj->refcount != 1 || 2737 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2738 continue; 2739 /* Remove object from fini list to prevent recursive invocation. */ 2740 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2741 /* Ensure that new references cannot be acquired. */ 2742 elm->obj->doomed = true; 2743 2744 hold_object(elm->obj); 2745 lock_release(rtld_bind_lock, lockstate); 2746 /* 2747 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2748 * When this happens, DT_FINI_ARRAY is processed first. 2749 */ 2750 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2751 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2752 for (index = elm->obj->fini_array_num - 1; index >= 0; 2753 index--) { 2754 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2755 dbg("calling fini function for %s at %p", 2756 elm->obj->path, (void *)fini_addr[index]); 2757 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2758 (void *)fini_addr[index], 0, 0, elm->obj->path); 2759 call_initfini_pointer(elm->obj, fini_addr[index]); 2760 } 2761 } 2762 } 2763 if (elm->obj->fini != (Elf_Addr)NULL) { 2764 dbg("calling fini function for %s at %p", elm->obj->path, 2765 (void *)elm->obj->fini); 2766 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2767 0, 0, elm->obj->path); 2768 call_initfini_pointer(elm->obj, elm->obj->fini); 2769 } 2770 wlock_acquire(rtld_bind_lock, lockstate); 2771 unhold_object(elm->obj); 2772 /* No need to free anything if process is going down. */ 2773 if (root != NULL) 2774 free(elm); 2775 /* 2776 * We must restart the list traversal after every fini call 2777 * because a dlclose() call from the fini function or from 2778 * another thread might have modified the reference counts. 2779 */ 2780 break; 2781 } 2782 } while (elm != NULL); 2783 errmsg_restore(saved_msg); 2784 } 2785 2786 /* 2787 * Call the initialization functions for each of the objects in 2788 * "list". All of the objects are expected to have non-NULL init 2789 * functions. 2790 */ 2791 static void 2792 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2793 { 2794 Objlist_Entry *elm; 2795 Obj_Entry *obj; 2796 char *saved_msg; 2797 Elf_Addr *init_addr; 2798 void (*reg)(void (*)(void)); 2799 int index; 2800 2801 /* 2802 * Clean init_scanned flag so that objects can be rechecked and 2803 * possibly initialized earlier if any of vectors called below 2804 * cause the change by using dlopen. 2805 */ 2806 TAILQ_FOREACH(obj, &obj_list, next) { 2807 if (obj->marker) 2808 continue; 2809 obj->init_scanned = false; 2810 } 2811 2812 /* 2813 * Preserve the current error message since an init function might 2814 * call into the dynamic linker and overwrite it. 2815 */ 2816 saved_msg = errmsg_save(); 2817 STAILQ_FOREACH(elm, list, link) { 2818 if (elm->obj->init_done) /* Initialized early. */ 2819 continue; 2820 /* 2821 * Race: other thread might try to use this object before current 2822 * one completes the initialization. Not much can be done here 2823 * without better locking. 2824 */ 2825 elm->obj->init_done = true; 2826 hold_object(elm->obj); 2827 reg = NULL; 2828 if (elm->obj == obj_main && obj_main->crt_no_init) { 2829 reg = (void (*)(void (*)(void)))get_program_var_addr( 2830 "__libc_atexit", lockstate); 2831 } 2832 lock_release(rtld_bind_lock, lockstate); 2833 if (reg != NULL) { 2834 reg(rtld_exit); 2835 rtld_exit_ptr = rtld_nop_exit; 2836 } 2837 2838 /* 2839 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2840 * When this happens, DT_INIT is processed first. 2841 */ 2842 if (elm->obj->init != (Elf_Addr)NULL) { 2843 dbg("calling init function for %s at %p", elm->obj->path, 2844 (void *)elm->obj->init); 2845 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2846 0, 0, elm->obj->path); 2847 call_init_pointer(elm->obj, elm->obj->init); 2848 } 2849 init_addr = (Elf_Addr *)elm->obj->init_array; 2850 if (init_addr != NULL) { 2851 for (index = 0; index < elm->obj->init_array_num; index++) { 2852 if (init_addr[index] != 0 && init_addr[index] != 1) { 2853 dbg("calling init function for %s at %p", elm->obj->path, 2854 (void *)init_addr[index]); 2855 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2856 (void *)init_addr[index], 0, 0, elm->obj->path); 2857 call_init_pointer(elm->obj, init_addr[index]); 2858 } 2859 } 2860 } 2861 wlock_acquire(rtld_bind_lock, lockstate); 2862 unhold_object(elm->obj); 2863 } 2864 errmsg_restore(saved_msg); 2865 } 2866 2867 static void 2868 objlist_clear(Objlist *list) 2869 { 2870 Objlist_Entry *elm; 2871 2872 while (!STAILQ_EMPTY(list)) { 2873 elm = STAILQ_FIRST(list); 2874 STAILQ_REMOVE_HEAD(list, link); 2875 free(elm); 2876 } 2877 } 2878 2879 static Objlist_Entry * 2880 objlist_find(Objlist *list, const Obj_Entry *obj) 2881 { 2882 Objlist_Entry *elm; 2883 2884 STAILQ_FOREACH(elm, list, link) 2885 if (elm->obj == obj) 2886 return elm; 2887 return NULL; 2888 } 2889 2890 static void 2891 objlist_init(Objlist *list) 2892 { 2893 STAILQ_INIT(list); 2894 } 2895 2896 static void 2897 objlist_push_head(Objlist *list, Obj_Entry *obj) 2898 { 2899 Objlist_Entry *elm; 2900 2901 elm = NEW(Objlist_Entry); 2902 elm->obj = obj; 2903 STAILQ_INSERT_HEAD(list, elm, link); 2904 } 2905 2906 static void 2907 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2908 { 2909 Objlist_Entry *elm; 2910 2911 elm = NEW(Objlist_Entry); 2912 elm->obj = obj; 2913 STAILQ_INSERT_TAIL(list, elm, link); 2914 } 2915 2916 static void 2917 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2918 { 2919 Objlist_Entry *elm, *listelm; 2920 2921 STAILQ_FOREACH(listelm, list, link) { 2922 if (listelm->obj == listobj) 2923 break; 2924 } 2925 elm = NEW(Objlist_Entry); 2926 elm->obj = obj; 2927 if (listelm != NULL) 2928 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2929 else 2930 STAILQ_INSERT_TAIL(list, elm, link); 2931 } 2932 2933 static void 2934 objlist_remove(Objlist *list, Obj_Entry *obj) 2935 { 2936 Objlist_Entry *elm; 2937 2938 if ((elm = objlist_find(list, obj)) != NULL) { 2939 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2940 free(elm); 2941 } 2942 } 2943 2944 /* 2945 * Relocate dag rooted in the specified object. 2946 * Returns 0 on success, or -1 on failure. 2947 */ 2948 2949 static int 2950 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2951 int flags, RtldLockState *lockstate) 2952 { 2953 Objlist_Entry *elm; 2954 int error; 2955 2956 error = 0; 2957 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2958 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2959 lockstate); 2960 if (error == -1) 2961 break; 2962 } 2963 return (error); 2964 } 2965 2966 /* 2967 * Prepare for, or clean after, relocating an object marked with 2968 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2969 * segments are remapped read-write. After relocations are done, the 2970 * segment's permissions are returned back to the modes specified in 2971 * the phdrs. If any relocation happened, or always for wired 2972 * program, COW is triggered. 2973 */ 2974 static int 2975 reloc_textrel_prot(Obj_Entry *obj, bool before) 2976 { 2977 const Elf_Phdr *ph; 2978 void *base; 2979 size_t l, sz; 2980 int prot; 2981 2982 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2983 l--, ph++) { 2984 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2985 continue; 2986 base = obj->relocbase + trunc_page(ph->p_vaddr); 2987 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2988 trunc_page(ph->p_vaddr); 2989 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2990 if (mprotect(base, sz, prot) == -1) { 2991 _rtld_error("%s: Cannot write-%sable text segment: %s", 2992 obj->path, before ? "en" : "dis", 2993 rtld_strerror(errno)); 2994 return (-1); 2995 } 2996 } 2997 return (0); 2998 } 2999 3000 /* 3001 * Relocate single object. 3002 * Returns 0 on success, or -1 on failure. 3003 */ 3004 static int 3005 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3006 int flags, RtldLockState *lockstate) 3007 { 3008 3009 if (obj->relocated) 3010 return (0); 3011 obj->relocated = true; 3012 if (obj != rtldobj) 3013 dbg("relocating \"%s\"", obj->path); 3014 3015 if (obj->symtab == NULL || obj->strtab == NULL || 3016 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3017 dbg("object %s has no run-time symbol table", obj->path); 3018 3019 /* There are relocations to the write-protected text segment. */ 3020 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3021 return (-1); 3022 3023 /* Process the non-PLT non-IFUNC relocations. */ 3024 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3025 return (-1); 3026 3027 /* Re-protected the text segment. */ 3028 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3029 return (-1); 3030 3031 /* Set the special PLT or GOT entries. */ 3032 init_pltgot(obj); 3033 3034 /* Process the PLT relocations. */ 3035 if (reloc_plt(obj, flags, lockstate) == -1) 3036 return (-1); 3037 /* Relocate the jump slots if we are doing immediate binding. */ 3038 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3039 lockstate) == -1) 3040 return (-1); 3041 3042 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3043 return (-1); 3044 3045 /* 3046 * Set up the magic number and version in the Obj_Entry. These 3047 * were checked in the crt1.o from the original ElfKit, so we 3048 * set them for backward compatibility. 3049 */ 3050 obj->magic = RTLD_MAGIC; 3051 obj->version = RTLD_VERSION; 3052 3053 return (0); 3054 } 3055 3056 /* 3057 * Relocate newly-loaded shared objects. The argument is a pointer to 3058 * the Obj_Entry for the first such object. All objects from the first 3059 * to the end of the list of objects are relocated. Returns 0 on success, 3060 * or -1 on failure. 3061 */ 3062 static int 3063 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3064 int flags, RtldLockState *lockstate) 3065 { 3066 Obj_Entry *obj; 3067 int error; 3068 3069 for (error = 0, obj = first; obj != NULL; 3070 obj = TAILQ_NEXT(obj, next)) { 3071 if (obj->marker) 3072 continue; 3073 error = relocate_object(obj, bind_now, rtldobj, flags, 3074 lockstate); 3075 if (error == -1) 3076 break; 3077 } 3078 return (error); 3079 } 3080 3081 /* 3082 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3083 * referencing STT_GNU_IFUNC symbols is postponed till the other 3084 * relocations are done. The indirect functions specified as 3085 * ifunc are allowed to call other symbols, so we need to have 3086 * objects relocated before asking for resolution from indirects. 3087 * 3088 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3089 * instead of the usual lazy handling of PLT slots. It is 3090 * consistent with how GNU does it. 3091 */ 3092 static int 3093 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3094 RtldLockState *lockstate) 3095 { 3096 3097 if (obj->ifuncs_resolved) 3098 return (0); 3099 obj->ifuncs_resolved = true; 3100 if (!obj->irelative && !obj->irelative_nonplt && 3101 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3102 !obj->non_plt_gnu_ifunc) 3103 return (0); 3104 if (obj_disable_relro(obj) == -1 || 3105 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3106 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3107 lockstate) == -1) || 3108 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3109 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3110 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3111 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3112 obj_enforce_relro(obj) == -1) 3113 return (-1); 3114 return (0); 3115 } 3116 3117 static int 3118 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3119 RtldLockState *lockstate) 3120 { 3121 Objlist_Entry *elm; 3122 Obj_Entry *obj; 3123 3124 STAILQ_FOREACH(elm, list, link) { 3125 obj = elm->obj; 3126 if (obj->marker) 3127 continue; 3128 if (resolve_object_ifunc(obj, bind_now, flags, 3129 lockstate) == -1) 3130 return (-1); 3131 } 3132 return (0); 3133 } 3134 3135 /* 3136 * Cleanup procedure. It will be called (by the atexit mechanism) just 3137 * before the process exits. 3138 */ 3139 static void 3140 rtld_exit(void) 3141 { 3142 RtldLockState lockstate; 3143 3144 wlock_acquire(rtld_bind_lock, &lockstate); 3145 dbg("rtld_exit()"); 3146 objlist_call_fini(&list_fini, NULL, &lockstate); 3147 /* No need to remove the items from the list, since we are exiting. */ 3148 if (!libmap_disable) 3149 lm_fini(); 3150 lock_release(rtld_bind_lock, &lockstate); 3151 } 3152 3153 static void 3154 rtld_nop_exit(void) 3155 { 3156 } 3157 3158 /* 3159 * Iterate over a search path, translate each element, and invoke the 3160 * callback on the result. 3161 */ 3162 static void * 3163 path_enumerate(const char *path, path_enum_proc callback, 3164 const char *refobj_path, void *arg) 3165 { 3166 const char *trans; 3167 if (path == NULL) 3168 return (NULL); 3169 3170 path += strspn(path, ":;"); 3171 while (*path != '\0') { 3172 size_t len; 3173 char *res; 3174 3175 len = strcspn(path, ":;"); 3176 trans = lm_findn(refobj_path, path, len); 3177 if (trans) 3178 res = callback(trans, strlen(trans), arg); 3179 else 3180 res = callback(path, len, arg); 3181 3182 if (res != NULL) 3183 return (res); 3184 3185 path += len; 3186 path += strspn(path, ":;"); 3187 } 3188 3189 return (NULL); 3190 } 3191 3192 struct try_library_args { 3193 const char *name; 3194 size_t namelen; 3195 char *buffer; 3196 size_t buflen; 3197 int fd; 3198 }; 3199 3200 static void * 3201 try_library_path(const char *dir, size_t dirlen, void *param) 3202 { 3203 struct try_library_args *arg; 3204 int fd; 3205 3206 arg = param; 3207 if (*dir == '/' || trust) { 3208 char *pathname; 3209 3210 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3211 return (NULL); 3212 3213 pathname = arg->buffer; 3214 strncpy(pathname, dir, dirlen); 3215 pathname[dirlen] = '/'; 3216 strcpy(pathname + dirlen + 1, arg->name); 3217 3218 dbg(" Trying \"%s\"", pathname); 3219 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3220 if (fd >= 0) { 3221 dbg(" Opened \"%s\", fd %d", pathname, fd); 3222 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3223 strcpy(pathname, arg->buffer); 3224 arg->fd = fd; 3225 return (pathname); 3226 } else { 3227 dbg(" Failed to open \"%s\": %s", 3228 pathname, rtld_strerror(errno)); 3229 } 3230 } 3231 return (NULL); 3232 } 3233 3234 static char * 3235 search_library_path(const char *name, const char *path, 3236 const char *refobj_path, int *fdp) 3237 { 3238 char *p; 3239 struct try_library_args arg; 3240 3241 if (path == NULL) 3242 return NULL; 3243 3244 arg.name = name; 3245 arg.namelen = strlen(name); 3246 arg.buffer = xmalloc(PATH_MAX); 3247 arg.buflen = PATH_MAX; 3248 arg.fd = -1; 3249 3250 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3251 *fdp = arg.fd; 3252 3253 free(arg.buffer); 3254 3255 return (p); 3256 } 3257 3258 3259 /* 3260 * Finds the library with the given name using the directory descriptors 3261 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3262 * 3263 * Returns a freshly-opened close-on-exec file descriptor for the library, 3264 * or -1 if the library cannot be found. 3265 */ 3266 static char * 3267 search_library_pathfds(const char *name, const char *path, int *fdp) 3268 { 3269 char *envcopy, *fdstr, *found, *last_token; 3270 size_t len; 3271 int dirfd, fd; 3272 3273 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3274 3275 /* Don't load from user-specified libdirs into setuid binaries. */ 3276 if (!trust) 3277 return (NULL); 3278 3279 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3280 if (path == NULL) 3281 return (NULL); 3282 3283 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3284 if (name[0] == '/') { 3285 dbg("Absolute path (%s) passed to %s", name, __func__); 3286 return (NULL); 3287 } 3288 3289 /* 3290 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3291 * copy of the path, as strtok_r rewrites separator tokens 3292 * with '\0'. 3293 */ 3294 found = NULL; 3295 envcopy = xstrdup(path); 3296 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3297 fdstr = strtok_r(NULL, ":", &last_token)) { 3298 dirfd = parse_integer(fdstr); 3299 if (dirfd < 0) { 3300 _rtld_error("failed to parse directory FD: '%s'", 3301 fdstr); 3302 break; 3303 } 3304 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3305 if (fd >= 0) { 3306 *fdp = fd; 3307 len = strlen(fdstr) + strlen(name) + 3; 3308 found = xmalloc(len); 3309 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3310 _rtld_error("error generating '%d/%s'", 3311 dirfd, name); 3312 rtld_die(); 3313 } 3314 dbg("open('%s') => %d", found, fd); 3315 break; 3316 } 3317 } 3318 free(envcopy); 3319 3320 return (found); 3321 } 3322 3323 3324 int 3325 dlclose(void *handle) 3326 { 3327 RtldLockState lockstate; 3328 int error; 3329 3330 wlock_acquire(rtld_bind_lock, &lockstate); 3331 error = dlclose_locked(handle, &lockstate); 3332 lock_release(rtld_bind_lock, &lockstate); 3333 return (error); 3334 } 3335 3336 static int 3337 dlclose_locked(void *handle, RtldLockState *lockstate) 3338 { 3339 Obj_Entry *root; 3340 3341 root = dlcheck(handle); 3342 if (root == NULL) 3343 return -1; 3344 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3345 root->path); 3346 3347 /* Unreference the object and its dependencies. */ 3348 root->dl_refcount--; 3349 3350 if (root->refcount == 1) { 3351 /* 3352 * The object will be no longer referenced, so we must unload it. 3353 * First, call the fini functions. 3354 */ 3355 objlist_call_fini(&list_fini, root, lockstate); 3356 3357 unref_dag(root); 3358 3359 /* Finish cleaning up the newly-unreferenced objects. */ 3360 GDB_STATE(RT_DELETE,&root->linkmap); 3361 unload_object(root, lockstate); 3362 GDB_STATE(RT_CONSISTENT,NULL); 3363 } else 3364 unref_dag(root); 3365 3366 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3367 return 0; 3368 } 3369 3370 char * 3371 dlerror(void) 3372 { 3373 char *msg = error_message; 3374 error_message = NULL; 3375 return msg; 3376 } 3377 3378 /* 3379 * This function is deprecated and has no effect. 3380 */ 3381 void 3382 dllockinit(void *context, 3383 void *(*_lock_create)(void *context) __unused, 3384 void (*_rlock_acquire)(void *lock) __unused, 3385 void (*_wlock_acquire)(void *lock) __unused, 3386 void (*_lock_release)(void *lock) __unused, 3387 void (*_lock_destroy)(void *lock) __unused, 3388 void (*context_destroy)(void *context)) 3389 { 3390 static void *cur_context; 3391 static void (*cur_context_destroy)(void *); 3392 3393 /* Just destroy the context from the previous call, if necessary. */ 3394 if (cur_context_destroy != NULL) 3395 cur_context_destroy(cur_context); 3396 cur_context = context; 3397 cur_context_destroy = context_destroy; 3398 } 3399 3400 void * 3401 dlopen(const char *name, int mode) 3402 { 3403 3404 return (rtld_dlopen(name, -1, mode)); 3405 } 3406 3407 void * 3408 fdlopen(int fd, int mode) 3409 { 3410 3411 return (rtld_dlopen(NULL, fd, mode)); 3412 } 3413 3414 static void * 3415 rtld_dlopen(const char *name, int fd, int mode) 3416 { 3417 RtldLockState lockstate; 3418 int lo_flags; 3419 3420 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3421 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3422 if (ld_tracing != NULL) { 3423 rlock_acquire(rtld_bind_lock, &lockstate); 3424 if (sigsetjmp(lockstate.env, 0) != 0) 3425 lock_upgrade(rtld_bind_lock, &lockstate); 3426 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3427 lock_release(rtld_bind_lock, &lockstate); 3428 } 3429 lo_flags = RTLD_LO_DLOPEN; 3430 if (mode & RTLD_NODELETE) 3431 lo_flags |= RTLD_LO_NODELETE; 3432 if (mode & RTLD_NOLOAD) 3433 lo_flags |= RTLD_LO_NOLOAD; 3434 if (mode & RTLD_DEEPBIND) 3435 lo_flags |= RTLD_LO_DEEPBIND; 3436 if (ld_tracing != NULL) 3437 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3438 3439 return (dlopen_object(name, fd, obj_main, lo_flags, 3440 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3441 } 3442 3443 static void 3444 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3445 { 3446 3447 obj->dl_refcount--; 3448 unref_dag(obj); 3449 if (obj->refcount == 0) 3450 unload_object(obj, lockstate); 3451 } 3452 3453 static Obj_Entry * 3454 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3455 int mode, RtldLockState *lockstate) 3456 { 3457 Obj_Entry *old_obj_tail; 3458 Obj_Entry *obj; 3459 Objlist initlist; 3460 RtldLockState mlockstate; 3461 int result; 3462 3463 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3464 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3465 refobj->path, lo_flags, mode); 3466 objlist_init(&initlist); 3467 3468 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3469 wlock_acquire(rtld_bind_lock, &mlockstate); 3470 lockstate = &mlockstate; 3471 } 3472 GDB_STATE(RT_ADD,NULL); 3473 3474 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3475 obj = NULL; 3476 if (name == NULL && fd == -1) { 3477 obj = obj_main; 3478 obj->refcount++; 3479 } else { 3480 obj = load_object(name, fd, refobj, lo_flags); 3481 } 3482 3483 if (obj) { 3484 obj->dl_refcount++; 3485 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3486 objlist_push_tail(&list_global, obj); 3487 if (globallist_next(old_obj_tail) != NULL) { 3488 /* We loaded something new. */ 3489 assert(globallist_next(old_obj_tail) == obj); 3490 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3491 obj->symbolic = true; 3492 result = 0; 3493 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3494 obj->static_tls && !allocate_tls_offset(obj)) { 3495 _rtld_error("%s: No space available " 3496 "for static Thread Local Storage", obj->path); 3497 result = -1; 3498 } 3499 if (result != -1) 3500 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3501 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3502 init_dag(obj); 3503 ref_dag(obj); 3504 if (result != -1) 3505 result = rtld_verify_versions(&obj->dagmembers); 3506 if (result != -1 && ld_tracing) 3507 goto trace; 3508 if (result == -1 || relocate_object_dag(obj, 3509 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3510 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3511 lockstate) == -1) { 3512 dlopen_cleanup(obj, lockstate); 3513 obj = NULL; 3514 } else if (lo_flags & RTLD_LO_EARLY) { 3515 /* 3516 * Do not call the init functions for early loaded 3517 * filtees. The image is still not initialized enough 3518 * for them to work. 3519 * 3520 * Our object is found by the global object list and 3521 * will be ordered among all init calls done right 3522 * before transferring control to main. 3523 */ 3524 } else { 3525 /* Make list of init functions to call. */ 3526 initlist_add_objects(obj, obj, &initlist); 3527 } 3528 /* 3529 * Process all no_delete or global objects here, given 3530 * them own DAGs to prevent their dependencies from being 3531 * unloaded. This has to be done after we have loaded all 3532 * of the dependencies, so that we do not miss any. 3533 */ 3534 if (obj != NULL) 3535 process_z(obj); 3536 } else { 3537 /* 3538 * Bump the reference counts for objects on this DAG. If 3539 * this is the first dlopen() call for the object that was 3540 * already loaded as a dependency, initialize the dag 3541 * starting at it. 3542 */ 3543 init_dag(obj); 3544 ref_dag(obj); 3545 3546 if ((lo_flags & RTLD_LO_TRACE) != 0) 3547 goto trace; 3548 } 3549 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3550 obj->z_nodelete) && !obj->ref_nodel) { 3551 dbg("obj %s nodelete", obj->path); 3552 ref_dag(obj); 3553 obj->z_nodelete = obj->ref_nodel = true; 3554 } 3555 } 3556 3557 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3558 name); 3559 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3560 3561 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3562 map_stacks_exec(lockstate); 3563 if (obj != NULL) 3564 distribute_static_tls(&initlist, lockstate); 3565 } 3566 3567 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3568 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3569 lockstate) == -1) { 3570 objlist_clear(&initlist); 3571 dlopen_cleanup(obj, lockstate); 3572 if (lockstate == &mlockstate) 3573 lock_release(rtld_bind_lock, lockstate); 3574 return (NULL); 3575 } 3576 3577 if (!(lo_flags & RTLD_LO_EARLY)) { 3578 /* Call the init functions. */ 3579 objlist_call_init(&initlist, lockstate); 3580 } 3581 objlist_clear(&initlist); 3582 if (lockstate == &mlockstate) 3583 lock_release(rtld_bind_lock, lockstate); 3584 return obj; 3585 trace: 3586 trace_loaded_objects(obj); 3587 if (lockstate == &mlockstate) 3588 lock_release(rtld_bind_lock, lockstate); 3589 exit(0); 3590 } 3591 3592 static void * 3593 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3594 int flags) 3595 { 3596 DoneList donelist; 3597 const Obj_Entry *obj, *defobj; 3598 const Elf_Sym *def; 3599 SymLook req; 3600 RtldLockState lockstate; 3601 tls_index ti; 3602 void *sym; 3603 int res; 3604 3605 def = NULL; 3606 defobj = NULL; 3607 symlook_init(&req, name); 3608 req.ventry = ve; 3609 req.flags = flags | SYMLOOK_IN_PLT; 3610 req.lockstate = &lockstate; 3611 3612 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3613 rlock_acquire(rtld_bind_lock, &lockstate); 3614 if (sigsetjmp(lockstate.env, 0) != 0) 3615 lock_upgrade(rtld_bind_lock, &lockstate); 3616 if (handle == NULL || handle == RTLD_NEXT || 3617 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3618 3619 if ((obj = obj_from_addr(retaddr)) == NULL) { 3620 _rtld_error("Cannot determine caller's shared object"); 3621 lock_release(rtld_bind_lock, &lockstate); 3622 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3623 return NULL; 3624 } 3625 if (handle == NULL) { /* Just the caller's shared object. */ 3626 res = symlook_obj(&req, obj); 3627 if (res == 0) { 3628 def = req.sym_out; 3629 defobj = req.defobj_out; 3630 } 3631 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3632 handle == RTLD_SELF) { /* ... caller included */ 3633 if (handle == RTLD_NEXT) 3634 obj = globallist_next(obj); 3635 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3636 if (obj->marker) 3637 continue; 3638 res = symlook_obj(&req, obj); 3639 if (res == 0) { 3640 if (def == NULL || 3641 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3642 def = req.sym_out; 3643 defobj = req.defobj_out; 3644 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3645 break; 3646 } 3647 } 3648 } 3649 /* 3650 * Search the dynamic linker itself, and possibly resolve the 3651 * symbol from there. This is how the application links to 3652 * dynamic linker services such as dlopen. 3653 */ 3654 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3655 res = symlook_obj(&req, &obj_rtld); 3656 if (res == 0) { 3657 def = req.sym_out; 3658 defobj = req.defobj_out; 3659 } 3660 } 3661 } else { 3662 assert(handle == RTLD_DEFAULT); 3663 res = symlook_default(&req, obj); 3664 if (res == 0) { 3665 defobj = req.defobj_out; 3666 def = req.sym_out; 3667 } 3668 } 3669 } else { 3670 if ((obj = dlcheck(handle)) == NULL) { 3671 lock_release(rtld_bind_lock, &lockstate); 3672 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3673 return NULL; 3674 } 3675 3676 donelist_init(&donelist); 3677 if (obj->mainprog) { 3678 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3679 res = symlook_global(&req, &donelist); 3680 if (res == 0) { 3681 def = req.sym_out; 3682 defobj = req.defobj_out; 3683 } 3684 /* 3685 * Search the dynamic linker itself, and possibly resolve the 3686 * symbol from there. This is how the application links to 3687 * dynamic linker services such as dlopen. 3688 */ 3689 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3690 res = symlook_obj(&req, &obj_rtld); 3691 if (res == 0) { 3692 def = req.sym_out; 3693 defobj = req.defobj_out; 3694 } 3695 } 3696 } 3697 else { 3698 /* Search the whole DAG rooted at the given object. */ 3699 res = symlook_list(&req, &obj->dagmembers, &donelist); 3700 if (res == 0) { 3701 def = req.sym_out; 3702 defobj = req.defobj_out; 3703 } 3704 } 3705 } 3706 3707 if (def != NULL) { 3708 lock_release(rtld_bind_lock, &lockstate); 3709 3710 /* 3711 * The value required by the caller is derived from the value 3712 * of the symbol. this is simply the relocated value of the 3713 * symbol. 3714 */ 3715 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3716 sym = make_function_pointer(def, defobj); 3717 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3718 sym = rtld_resolve_ifunc(defobj, def); 3719 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3720 ti.ti_module = defobj->tlsindex; 3721 ti.ti_offset = def->st_value; 3722 sym = __tls_get_addr(&ti); 3723 } else 3724 sym = defobj->relocbase + def->st_value; 3725 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3726 return (sym); 3727 } 3728 3729 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3730 ve != NULL ? ve->name : ""); 3731 lock_release(rtld_bind_lock, &lockstate); 3732 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3733 return NULL; 3734 } 3735 3736 void * 3737 dlsym(void *handle, const char *name) 3738 { 3739 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3740 SYMLOOK_DLSYM); 3741 } 3742 3743 dlfunc_t 3744 dlfunc(void *handle, const char *name) 3745 { 3746 union { 3747 void *d; 3748 dlfunc_t f; 3749 } rv; 3750 3751 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3752 SYMLOOK_DLSYM); 3753 return (rv.f); 3754 } 3755 3756 void * 3757 dlvsym(void *handle, const char *name, const char *version) 3758 { 3759 Ver_Entry ventry; 3760 3761 ventry.name = version; 3762 ventry.file = NULL; 3763 ventry.hash = elf_hash(version); 3764 ventry.flags= 0; 3765 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3766 SYMLOOK_DLSYM); 3767 } 3768 3769 int 3770 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3771 { 3772 const Obj_Entry *obj; 3773 RtldLockState lockstate; 3774 3775 rlock_acquire(rtld_bind_lock, &lockstate); 3776 obj = obj_from_addr(addr); 3777 if (obj == NULL) { 3778 _rtld_error("No shared object contains address"); 3779 lock_release(rtld_bind_lock, &lockstate); 3780 return (0); 3781 } 3782 rtld_fill_dl_phdr_info(obj, phdr_info); 3783 lock_release(rtld_bind_lock, &lockstate); 3784 return (1); 3785 } 3786 3787 int 3788 dladdr(const void *addr, Dl_info *info) 3789 { 3790 const Obj_Entry *obj; 3791 const Elf_Sym *def; 3792 void *symbol_addr; 3793 unsigned long symoffset; 3794 RtldLockState lockstate; 3795 3796 rlock_acquire(rtld_bind_lock, &lockstate); 3797 obj = obj_from_addr(addr); 3798 if (obj == NULL) { 3799 _rtld_error("No shared object contains address"); 3800 lock_release(rtld_bind_lock, &lockstate); 3801 return 0; 3802 } 3803 info->dli_fname = obj->path; 3804 info->dli_fbase = obj->mapbase; 3805 info->dli_saddr = (void *)0; 3806 info->dli_sname = NULL; 3807 3808 /* 3809 * Walk the symbol list looking for the symbol whose address is 3810 * closest to the address sent in. 3811 */ 3812 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3813 def = obj->symtab + symoffset; 3814 3815 /* 3816 * For skip the symbol if st_shndx is either SHN_UNDEF or 3817 * SHN_COMMON. 3818 */ 3819 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3820 continue; 3821 3822 /* 3823 * If the symbol is greater than the specified address, or if it 3824 * is further away from addr than the current nearest symbol, 3825 * then reject it. 3826 */ 3827 symbol_addr = obj->relocbase + def->st_value; 3828 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3829 continue; 3830 3831 /* Update our idea of the nearest symbol. */ 3832 info->dli_sname = obj->strtab + def->st_name; 3833 info->dli_saddr = symbol_addr; 3834 3835 /* Exact match? */ 3836 if (info->dli_saddr == addr) 3837 break; 3838 } 3839 lock_release(rtld_bind_lock, &lockstate); 3840 return 1; 3841 } 3842 3843 int 3844 dlinfo(void *handle, int request, void *p) 3845 { 3846 const Obj_Entry *obj; 3847 RtldLockState lockstate; 3848 int error; 3849 3850 rlock_acquire(rtld_bind_lock, &lockstate); 3851 3852 if (handle == NULL || handle == RTLD_SELF) { 3853 void *retaddr; 3854 3855 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3856 if ((obj = obj_from_addr(retaddr)) == NULL) 3857 _rtld_error("Cannot determine caller's shared object"); 3858 } else 3859 obj = dlcheck(handle); 3860 3861 if (obj == NULL) { 3862 lock_release(rtld_bind_lock, &lockstate); 3863 return (-1); 3864 } 3865 3866 error = 0; 3867 switch (request) { 3868 case RTLD_DI_LINKMAP: 3869 *((struct link_map const **)p) = &obj->linkmap; 3870 break; 3871 case RTLD_DI_ORIGIN: 3872 error = rtld_dirname(obj->path, p); 3873 break; 3874 3875 case RTLD_DI_SERINFOSIZE: 3876 case RTLD_DI_SERINFO: 3877 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3878 break; 3879 3880 default: 3881 _rtld_error("Invalid request %d passed to dlinfo()", request); 3882 error = -1; 3883 } 3884 3885 lock_release(rtld_bind_lock, &lockstate); 3886 3887 return (error); 3888 } 3889 3890 static void 3891 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3892 { 3893 3894 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3895 phdr_info->dlpi_name = obj->path; 3896 phdr_info->dlpi_phdr = obj->phdr; 3897 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3898 phdr_info->dlpi_tls_modid = obj->tlsindex; 3899 phdr_info->dlpi_tls_data = obj->tlsinit; 3900 phdr_info->dlpi_adds = obj_loads; 3901 phdr_info->dlpi_subs = obj_loads - obj_count; 3902 } 3903 3904 int 3905 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3906 { 3907 struct dl_phdr_info phdr_info; 3908 Obj_Entry *obj, marker; 3909 RtldLockState bind_lockstate, phdr_lockstate; 3910 int error; 3911 3912 init_marker(&marker); 3913 error = 0; 3914 3915 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3916 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3917 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3918 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3919 rtld_fill_dl_phdr_info(obj, &phdr_info); 3920 hold_object(obj); 3921 lock_release(rtld_bind_lock, &bind_lockstate); 3922 3923 error = callback(&phdr_info, sizeof phdr_info, param); 3924 3925 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3926 unhold_object(obj); 3927 obj = globallist_next(&marker); 3928 TAILQ_REMOVE(&obj_list, &marker, next); 3929 if (error != 0) { 3930 lock_release(rtld_bind_lock, &bind_lockstate); 3931 lock_release(rtld_phdr_lock, &phdr_lockstate); 3932 return (error); 3933 } 3934 } 3935 3936 if (error == 0) { 3937 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3938 lock_release(rtld_bind_lock, &bind_lockstate); 3939 error = callback(&phdr_info, sizeof(phdr_info), param); 3940 } 3941 lock_release(rtld_phdr_lock, &phdr_lockstate); 3942 return (error); 3943 } 3944 3945 static void * 3946 fill_search_info(const char *dir, size_t dirlen, void *param) 3947 { 3948 struct fill_search_info_args *arg; 3949 3950 arg = param; 3951 3952 if (arg->request == RTLD_DI_SERINFOSIZE) { 3953 arg->serinfo->dls_cnt ++; 3954 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3955 } else { 3956 struct dl_serpath *s_entry; 3957 3958 s_entry = arg->serpath; 3959 s_entry->dls_name = arg->strspace; 3960 s_entry->dls_flags = arg->flags; 3961 3962 strncpy(arg->strspace, dir, dirlen); 3963 arg->strspace[dirlen] = '\0'; 3964 3965 arg->strspace += dirlen + 1; 3966 arg->serpath++; 3967 } 3968 3969 return (NULL); 3970 } 3971 3972 static int 3973 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3974 { 3975 struct dl_serinfo _info; 3976 struct fill_search_info_args args; 3977 3978 args.request = RTLD_DI_SERINFOSIZE; 3979 args.serinfo = &_info; 3980 3981 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3982 _info.dls_cnt = 0; 3983 3984 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3985 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3986 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3987 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3988 if (!obj->z_nodeflib) 3989 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3990 3991 3992 if (request == RTLD_DI_SERINFOSIZE) { 3993 info->dls_size = _info.dls_size; 3994 info->dls_cnt = _info.dls_cnt; 3995 return (0); 3996 } 3997 3998 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3999 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4000 return (-1); 4001 } 4002 4003 args.request = RTLD_DI_SERINFO; 4004 args.serinfo = info; 4005 args.serpath = &info->dls_serpath[0]; 4006 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4007 4008 args.flags = LA_SER_RUNPATH; 4009 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4010 return (-1); 4011 4012 args.flags = LA_SER_LIBPATH; 4013 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4014 return (-1); 4015 4016 args.flags = LA_SER_RUNPATH; 4017 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4018 return (-1); 4019 4020 args.flags = LA_SER_CONFIG; 4021 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4022 != NULL) 4023 return (-1); 4024 4025 args.flags = LA_SER_DEFAULT; 4026 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4027 fill_search_info, NULL, &args) != NULL) 4028 return (-1); 4029 return (0); 4030 } 4031 4032 static int 4033 rtld_dirname(const char *path, char *bname) 4034 { 4035 const char *endp; 4036 4037 /* Empty or NULL string gets treated as "." */ 4038 if (path == NULL || *path == '\0') { 4039 bname[0] = '.'; 4040 bname[1] = '\0'; 4041 return (0); 4042 } 4043 4044 /* Strip trailing slashes */ 4045 endp = path + strlen(path) - 1; 4046 while (endp > path && *endp == '/') 4047 endp--; 4048 4049 /* Find the start of the dir */ 4050 while (endp > path && *endp != '/') 4051 endp--; 4052 4053 /* Either the dir is "/" or there are no slashes */ 4054 if (endp == path) { 4055 bname[0] = *endp == '/' ? '/' : '.'; 4056 bname[1] = '\0'; 4057 return (0); 4058 } else { 4059 do { 4060 endp--; 4061 } while (endp > path && *endp == '/'); 4062 } 4063 4064 if (endp - path + 2 > PATH_MAX) 4065 { 4066 _rtld_error("Filename is too long: %s", path); 4067 return(-1); 4068 } 4069 4070 strncpy(bname, path, endp - path + 1); 4071 bname[endp - path + 1] = '\0'; 4072 return (0); 4073 } 4074 4075 static int 4076 rtld_dirname_abs(const char *path, char *base) 4077 { 4078 char *last; 4079 4080 if (realpath(path, base) == NULL) { 4081 _rtld_error("realpath \"%s\" failed (%s)", path, 4082 rtld_strerror(errno)); 4083 return (-1); 4084 } 4085 dbg("%s -> %s", path, base); 4086 last = strrchr(base, '/'); 4087 if (last == NULL) { 4088 _rtld_error("non-abs result from realpath \"%s\"", path); 4089 return (-1); 4090 } 4091 if (last != base) 4092 *last = '\0'; 4093 return (0); 4094 } 4095 4096 static void 4097 linkmap_add(Obj_Entry *obj) 4098 { 4099 struct link_map *l, *prev; 4100 4101 l = &obj->linkmap; 4102 l->l_name = obj->path; 4103 l->l_base = obj->mapbase; 4104 l->l_ld = obj->dynamic; 4105 l->l_addr = obj->relocbase; 4106 4107 if (r_debug.r_map == NULL) { 4108 r_debug.r_map = l; 4109 return; 4110 } 4111 4112 /* 4113 * Scan to the end of the list, but not past the entry for the 4114 * dynamic linker, which we want to keep at the very end. 4115 */ 4116 for (prev = r_debug.r_map; 4117 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4118 prev = prev->l_next) 4119 ; 4120 4121 /* Link in the new entry. */ 4122 l->l_prev = prev; 4123 l->l_next = prev->l_next; 4124 if (l->l_next != NULL) 4125 l->l_next->l_prev = l; 4126 prev->l_next = l; 4127 } 4128 4129 static void 4130 linkmap_delete(Obj_Entry *obj) 4131 { 4132 struct link_map *l; 4133 4134 l = &obj->linkmap; 4135 if (l->l_prev == NULL) { 4136 if ((r_debug.r_map = l->l_next) != NULL) 4137 l->l_next->l_prev = NULL; 4138 return; 4139 } 4140 4141 if ((l->l_prev->l_next = l->l_next) != NULL) 4142 l->l_next->l_prev = l->l_prev; 4143 } 4144 4145 /* 4146 * Function for the debugger to set a breakpoint on to gain control. 4147 * 4148 * The two parameters allow the debugger to easily find and determine 4149 * what the runtime loader is doing and to whom it is doing it. 4150 * 4151 * When the loadhook trap is hit (r_debug_state, set at program 4152 * initialization), the arguments can be found on the stack: 4153 * 4154 * +8 struct link_map *m 4155 * +4 struct r_debug *rd 4156 * +0 RetAddr 4157 */ 4158 void 4159 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4160 { 4161 /* 4162 * The following is a hack to force the compiler to emit calls to 4163 * this function, even when optimizing. If the function is empty, 4164 * the compiler is not obliged to emit any code for calls to it, 4165 * even when marked __noinline. However, gdb depends on those 4166 * calls being made. 4167 */ 4168 __compiler_membar(); 4169 } 4170 4171 /* 4172 * A function called after init routines have completed. This can be used to 4173 * break before a program's entry routine is called, and can be used when 4174 * main is not available in the symbol table. 4175 */ 4176 void 4177 _r_debug_postinit(struct link_map *m __unused) 4178 { 4179 4180 /* See r_debug_state(). */ 4181 __compiler_membar(); 4182 } 4183 4184 static void 4185 release_object(Obj_Entry *obj) 4186 { 4187 4188 if (obj->holdcount > 0) { 4189 obj->unholdfree = true; 4190 return; 4191 } 4192 munmap(obj->mapbase, obj->mapsize); 4193 linkmap_delete(obj); 4194 obj_free(obj); 4195 } 4196 4197 /* 4198 * Get address of the pointer variable in the main program. 4199 * Prefer non-weak symbol over the weak one. 4200 */ 4201 static const void ** 4202 get_program_var_addr(const char *name, RtldLockState *lockstate) 4203 { 4204 SymLook req; 4205 DoneList donelist; 4206 4207 symlook_init(&req, name); 4208 req.lockstate = lockstate; 4209 donelist_init(&donelist); 4210 if (symlook_global(&req, &donelist) != 0) 4211 return (NULL); 4212 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4213 return ((const void **)make_function_pointer(req.sym_out, 4214 req.defobj_out)); 4215 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4216 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4217 else 4218 return ((const void **)(req.defobj_out->relocbase + 4219 req.sym_out->st_value)); 4220 } 4221 4222 /* 4223 * Set a pointer variable in the main program to the given value. This 4224 * is used to set key variables such as "environ" before any of the 4225 * init functions are called. 4226 */ 4227 static void 4228 set_program_var(const char *name, const void *value) 4229 { 4230 const void **addr; 4231 4232 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4233 dbg("\"%s\": *%p <-- %p", name, addr, value); 4234 *addr = value; 4235 } 4236 } 4237 4238 /* 4239 * Search the global objects, including dependencies and main object, 4240 * for the given symbol. 4241 */ 4242 static int 4243 symlook_global(SymLook *req, DoneList *donelist) 4244 { 4245 SymLook req1; 4246 const Objlist_Entry *elm; 4247 int res; 4248 4249 symlook_init_from_req(&req1, req); 4250 4251 /* Search all objects loaded at program start up. */ 4252 if (req->defobj_out == NULL || 4253 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4254 res = symlook_list(&req1, &list_main, donelist); 4255 if (res == 0 && (req->defobj_out == NULL || 4256 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4257 req->sym_out = req1.sym_out; 4258 req->defobj_out = req1.defobj_out; 4259 assert(req->defobj_out != NULL); 4260 } 4261 } 4262 4263 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4264 STAILQ_FOREACH(elm, &list_global, link) { 4265 if (req->defobj_out != NULL && 4266 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4267 break; 4268 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4269 if (res == 0 && (req->defobj_out == NULL || 4270 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4271 req->sym_out = req1.sym_out; 4272 req->defobj_out = req1.defobj_out; 4273 assert(req->defobj_out != NULL); 4274 } 4275 } 4276 4277 return (req->sym_out != NULL ? 0 : ESRCH); 4278 } 4279 4280 /* 4281 * Given a symbol name in a referencing object, find the corresponding 4282 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4283 * no definition was found. Returns a pointer to the Obj_Entry of the 4284 * defining object via the reference parameter DEFOBJ_OUT. 4285 */ 4286 static int 4287 symlook_default(SymLook *req, const Obj_Entry *refobj) 4288 { 4289 DoneList donelist; 4290 const Objlist_Entry *elm; 4291 SymLook req1; 4292 int res; 4293 4294 donelist_init(&donelist); 4295 symlook_init_from_req(&req1, req); 4296 4297 /* 4298 * Look first in the referencing object if linked symbolically, 4299 * and similarly handle protected symbols. 4300 */ 4301 res = symlook_obj(&req1, refobj); 4302 if (res == 0 && (refobj->symbolic || 4303 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4304 req->sym_out = req1.sym_out; 4305 req->defobj_out = req1.defobj_out; 4306 assert(req->defobj_out != NULL); 4307 } 4308 if (refobj->symbolic || req->defobj_out != NULL) 4309 donelist_check(&donelist, refobj); 4310 4311 symlook_global(req, &donelist); 4312 4313 /* Search all dlopened DAGs containing the referencing object. */ 4314 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4315 if (req->sym_out != NULL && 4316 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4317 break; 4318 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4319 if (res == 0 && (req->sym_out == NULL || 4320 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4321 req->sym_out = req1.sym_out; 4322 req->defobj_out = req1.defobj_out; 4323 assert(req->defobj_out != NULL); 4324 } 4325 } 4326 4327 /* 4328 * Search the dynamic linker itself, and possibly resolve the 4329 * symbol from there. This is how the application links to 4330 * dynamic linker services such as dlopen. 4331 */ 4332 if (req->sym_out == NULL || 4333 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4334 res = symlook_obj(&req1, &obj_rtld); 4335 if (res == 0) { 4336 req->sym_out = req1.sym_out; 4337 req->defobj_out = req1.defobj_out; 4338 assert(req->defobj_out != NULL); 4339 } 4340 } 4341 4342 return (req->sym_out != NULL ? 0 : ESRCH); 4343 } 4344 4345 static int 4346 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4347 { 4348 const Elf_Sym *def; 4349 const Obj_Entry *defobj; 4350 const Objlist_Entry *elm; 4351 SymLook req1; 4352 int res; 4353 4354 def = NULL; 4355 defobj = NULL; 4356 STAILQ_FOREACH(elm, objlist, link) { 4357 if (donelist_check(dlp, elm->obj)) 4358 continue; 4359 symlook_init_from_req(&req1, req); 4360 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4361 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4362 def = req1.sym_out; 4363 defobj = req1.defobj_out; 4364 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4365 break; 4366 } 4367 } 4368 } 4369 if (def != NULL) { 4370 req->sym_out = def; 4371 req->defobj_out = defobj; 4372 return (0); 4373 } 4374 return (ESRCH); 4375 } 4376 4377 /* 4378 * Search the chain of DAGS cointed to by the given Needed_Entry 4379 * for a symbol of the given name. Each DAG is scanned completely 4380 * before advancing to the next one. Returns a pointer to the symbol, 4381 * or NULL if no definition was found. 4382 */ 4383 static int 4384 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4385 { 4386 const Elf_Sym *def; 4387 const Needed_Entry *n; 4388 const Obj_Entry *defobj; 4389 SymLook req1; 4390 int res; 4391 4392 def = NULL; 4393 defobj = NULL; 4394 symlook_init_from_req(&req1, req); 4395 for (n = needed; n != NULL; n = n->next) { 4396 if (n->obj == NULL || 4397 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4398 continue; 4399 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4400 def = req1.sym_out; 4401 defobj = req1.defobj_out; 4402 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4403 break; 4404 } 4405 } 4406 if (def != NULL) { 4407 req->sym_out = def; 4408 req->defobj_out = defobj; 4409 return (0); 4410 } 4411 return (ESRCH); 4412 } 4413 4414 /* 4415 * Search the symbol table of a single shared object for a symbol of 4416 * the given name and version, if requested. Returns a pointer to the 4417 * symbol, or NULL if no definition was found. If the object is 4418 * filter, return filtered symbol from filtee. 4419 * 4420 * The symbol's hash value is passed in for efficiency reasons; that 4421 * eliminates many recomputations of the hash value. 4422 */ 4423 int 4424 symlook_obj(SymLook *req, const Obj_Entry *obj) 4425 { 4426 DoneList donelist; 4427 SymLook req1; 4428 int flags, res, mres; 4429 4430 /* 4431 * If there is at least one valid hash at this point, we prefer to 4432 * use the faster GNU version if available. 4433 */ 4434 if (obj->valid_hash_gnu) 4435 mres = symlook_obj1_gnu(req, obj); 4436 else if (obj->valid_hash_sysv) 4437 mres = symlook_obj1_sysv(req, obj); 4438 else 4439 return (EINVAL); 4440 4441 if (mres == 0) { 4442 if (obj->needed_filtees != NULL) { 4443 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4444 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4445 donelist_init(&donelist); 4446 symlook_init_from_req(&req1, req); 4447 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4448 if (res == 0) { 4449 req->sym_out = req1.sym_out; 4450 req->defobj_out = req1.defobj_out; 4451 } 4452 return (res); 4453 } 4454 if (obj->needed_aux_filtees != NULL) { 4455 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4456 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4457 donelist_init(&donelist); 4458 symlook_init_from_req(&req1, req); 4459 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4460 if (res == 0) { 4461 req->sym_out = req1.sym_out; 4462 req->defobj_out = req1.defobj_out; 4463 return (res); 4464 } 4465 } 4466 } 4467 return (mres); 4468 } 4469 4470 /* Symbol match routine common to both hash functions */ 4471 static bool 4472 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4473 const unsigned long symnum) 4474 { 4475 Elf_Versym verndx; 4476 const Elf_Sym *symp; 4477 const char *strp; 4478 4479 symp = obj->symtab + symnum; 4480 strp = obj->strtab + symp->st_name; 4481 4482 switch (ELF_ST_TYPE(symp->st_info)) { 4483 case STT_FUNC: 4484 case STT_NOTYPE: 4485 case STT_OBJECT: 4486 case STT_COMMON: 4487 case STT_GNU_IFUNC: 4488 if (symp->st_value == 0) 4489 return (false); 4490 /* fallthrough */ 4491 case STT_TLS: 4492 if (symp->st_shndx != SHN_UNDEF) 4493 break; 4494 #ifndef __mips__ 4495 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4496 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4497 break; 4498 #endif 4499 /* fallthrough */ 4500 default: 4501 return (false); 4502 } 4503 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4504 return (false); 4505 4506 if (req->ventry == NULL) { 4507 if (obj->versyms != NULL) { 4508 verndx = VER_NDX(obj->versyms[symnum]); 4509 if (verndx > obj->vernum) { 4510 _rtld_error( 4511 "%s: symbol %s references wrong version %d", 4512 obj->path, obj->strtab + symnum, verndx); 4513 return (false); 4514 } 4515 /* 4516 * If we are not called from dlsym (i.e. this 4517 * is a normal relocation from unversioned 4518 * binary), accept the symbol immediately if 4519 * it happens to have first version after this 4520 * shared object became versioned. Otherwise, 4521 * if symbol is versioned and not hidden, 4522 * remember it. If it is the only symbol with 4523 * this name exported by the shared object, it 4524 * will be returned as a match by the calling 4525 * function. If symbol is global (verndx < 2) 4526 * accept it unconditionally. 4527 */ 4528 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4529 verndx == VER_NDX_GIVEN) { 4530 result->sym_out = symp; 4531 return (true); 4532 } 4533 else if (verndx >= VER_NDX_GIVEN) { 4534 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4535 == 0) { 4536 if (result->vsymp == NULL) 4537 result->vsymp = symp; 4538 result->vcount++; 4539 } 4540 return (false); 4541 } 4542 } 4543 result->sym_out = symp; 4544 return (true); 4545 } 4546 if (obj->versyms == NULL) { 4547 if (object_match_name(obj, req->ventry->name)) { 4548 _rtld_error("%s: object %s should provide version %s " 4549 "for symbol %s", obj_rtld.path, obj->path, 4550 req->ventry->name, obj->strtab + symnum); 4551 return (false); 4552 } 4553 } else { 4554 verndx = VER_NDX(obj->versyms[symnum]); 4555 if (verndx > obj->vernum) { 4556 _rtld_error("%s: symbol %s references wrong version %d", 4557 obj->path, obj->strtab + symnum, verndx); 4558 return (false); 4559 } 4560 if (obj->vertab[verndx].hash != req->ventry->hash || 4561 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4562 /* 4563 * Version does not match. Look if this is a 4564 * global symbol and if it is not hidden. If 4565 * global symbol (verndx < 2) is available, 4566 * use it. Do not return symbol if we are 4567 * called by dlvsym, because dlvsym looks for 4568 * a specific version and default one is not 4569 * what dlvsym wants. 4570 */ 4571 if ((req->flags & SYMLOOK_DLSYM) || 4572 (verndx >= VER_NDX_GIVEN) || 4573 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4574 return (false); 4575 } 4576 } 4577 result->sym_out = symp; 4578 return (true); 4579 } 4580 4581 /* 4582 * Search for symbol using SysV hash function. 4583 * obj->buckets is known not to be NULL at this point; the test for this was 4584 * performed with the obj->valid_hash_sysv assignment. 4585 */ 4586 static int 4587 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4588 { 4589 unsigned long symnum; 4590 Sym_Match_Result matchres; 4591 4592 matchres.sym_out = NULL; 4593 matchres.vsymp = NULL; 4594 matchres.vcount = 0; 4595 4596 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4597 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4598 if (symnum >= obj->nchains) 4599 return (ESRCH); /* Bad object */ 4600 4601 if (matched_symbol(req, obj, &matchres, symnum)) { 4602 req->sym_out = matchres.sym_out; 4603 req->defobj_out = obj; 4604 return (0); 4605 } 4606 } 4607 if (matchres.vcount == 1) { 4608 req->sym_out = matchres.vsymp; 4609 req->defobj_out = obj; 4610 return (0); 4611 } 4612 return (ESRCH); 4613 } 4614 4615 /* Search for symbol using GNU hash function */ 4616 static int 4617 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4618 { 4619 Elf_Addr bloom_word; 4620 const Elf32_Word *hashval; 4621 Elf32_Word bucket; 4622 Sym_Match_Result matchres; 4623 unsigned int h1, h2; 4624 unsigned long symnum; 4625 4626 matchres.sym_out = NULL; 4627 matchres.vsymp = NULL; 4628 matchres.vcount = 0; 4629 4630 /* Pick right bitmask word from Bloom filter array */ 4631 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4632 obj->maskwords_bm_gnu]; 4633 4634 /* Calculate modulus word size of gnu hash and its derivative */ 4635 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4636 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4637 4638 /* Filter out the "definitely not in set" queries */ 4639 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4640 return (ESRCH); 4641 4642 /* Locate hash chain and corresponding value element*/ 4643 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4644 if (bucket == 0) 4645 return (ESRCH); 4646 hashval = &obj->chain_zero_gnu[bucket]; 4647 do { 4648 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4649 symnum = hashval - obj->chain_zero_gnu; 4650 if (matched_symbol(req, obj, &matchres, symnum)) { 4651 req->sym_out = matchres.sym_out; 4652 req->defobj_out = obj; 4653 return (0); 4654 } 4655 } 4656 } while ((*hashval++ & 1) == 0); 4657 if (matchres.vcount == 1) { 4658 req->sym_out = matchres.vsymp; 4659 req->defobj_out = obj; 4660 return (0); 4661 } 4662 return (ESRCH); 4663 } 4664 4665 static void 4666 trace_loaded_objects(Obj_Entry *obj) 4667 { 4668 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4669 int c; 4670 4671 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4672 main_local = ""; 4673 4674 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4675 fmt1 = "\t%o => %p (%x)\n"; 4676 4677 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4678 fmt2 = "\t%o (%x)\n"; 4679 4680 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4681 4682 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4683 Needed_Entry *needed; 4684 const char *name, *path; 4685 bool is_lib; 4686 4687 if (obj->marker) 4688 continue; 4689 if (list_containers && obj->needed != NULL) 4690 rtld_printf("%s:\n", obj->path); 4691 for (needed = obj->needed; needed; needed = needed->next) { 4692 if (needed->obj != NULL) { 4693 if (needed->obj->traced && !list_containers) 4694 continue; 4695 needed->obj->traced = true; 4696 path = needed->obj->path; 4697 } else 4698 path = "not found"; 4699 4700 name = obj->strtab + needed->name; 4701 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4702 4703 fmt = is_lib ? fmt1 : fmt2; 4704 while ((c = *fmt++) != '\0') { 4705 switch (c) { 4706 default: 4707 rtld_putchar(c); 4708 continue; 4709 case '\\': 4710 switch (c = *fmt) { 4711 case '\0': 4712 continue; 4713 case 'n': 4714 rtld_putchar('\n'); 4715 break; 4716 case 't': 4717 rtld_putchar('\t'); 4718 break; 4719 } 4720 break; 4721 case '%': 4722 switch (c = *fmt) { 4723 case '\0': 4724 continue; 4725 case '%': 4726 default: 4727 rtld_putchar(c); 4728 break; 4729 case 'A': 4730 rtld_putstr(main_local); 4731 break; 4732 case 'a': 4733 rtld_putstr(obj_main->path); 4734 break; 4735 case 'o': 4736 rtld_putstr(name); 4737 break; 4738 #if 0 4739 case 'm': 4740 rtld_printf("%d", sodp->sod_major); 4741 break; 4742 case 'n': 4743 rtld_printf("%d", sodp->sod_minor); 4744 break; 4745 #endif 4746 case 'p': 4747 rtld_putstr(path); 4748 break; 4749 case 'x': 4750 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4751 0); 4752 break; 4753 } 4754 break; 4755 } 4756 ++fmt; 4757 } 4758 } 4759 } 4760 } 4761 4762 /* 4763 * Unload a dlopened object and its dependencies from memory and from 4764 * our data structures. It is assumed that the DAG rooted in the 4765 * object has already been unreferenced, and that the object has a 4766 * reference count of 0. 4767 */ 4768 static void 4769 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4770 { 4771 Obj_Entry marker, *obj, *next; 4772 4773 assert(root->refcount == 0); 4774 4775 /* 4776 * Pass over the DAG removing unreferenced objects from 4777 * appropriate lists. 4778 */ 4779 unlink_object(root); 4780 4781 /* Unmap all objects that are no longer referenced. */ 4782 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4783 next = TAILQ_NEXT(obj, next); 4784 if (obj->marker || obj->refcount != 0) 4785 continue; 4786 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4787 obj->mapsize, 0, obj->path); 4788 dbg("unloading \"%s\"", obj->path); 4789 /* 4790 * Unlink the object now to prevent new references from 4791 * being acquired while the bind lock is dropped in 4792 * recursive dlclose() invocations. 4793 */ 4794 TAILQ_REMOVE(&obj_list, obj, next); 4795 obj_count--; 4796 4797 if (obj->filtees_loaded) { 4798 if (next != NULL) { 4799 init_marker(&marker); 4800 TAILQ_INSERT_BEFORE(next, &marker, next); 4801 unload_filtees(obj, lockstate); 4802 next = TAILQ_NEXT(&marker, next); 4803 TAILQ_REMOVE(&obj_list, &marker, next); 4804 } else 4805 unload_filtees(obj, lockstate); 4806 } 4807 release_object(obj); 4808 } 4809 } 4810 4811 static void 4812 unlink_object(Obj_Entry *root) 4813 { 4814 Objlist_Entry *elm; 4815 4816 if (root->refcount == 0) { 4817 /* Remove the object from the RTLD_GLOBAL list. */ 4818 objlist_remove(&list_global, root); 4819 4820 /* Remove the object from all objects' DAG lists. */ 4821 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4822 objlist_remove(&elm->obj->dldags, root); 4823 if (elm->obj != root) 4824 unlink_object(elm->obj); 4825 } 4826 } 4827 } 4828 4829 static void 4830 ref_dag(Obj_Entry *root) 4831 { 4832 Objlist_Entry *elm; 4833 4834 assert(root->dag_inited); 4835 STAILQ_FOREACH(elm, &root->dagmembers, link) 4836 elm->obj->refcount++; 4837 } 4838 4839 static void 4840 unref_dag(Obj_Entry *root) 4841 { 4842 Objlist_Entry *elm; 4843 4844 assert(root->dag_inited); 4845 STAILQ_FOREACH(elm, &root->dagmembers, link) 4846 elm->obj->refcount--; 4847 } 4848 4849 /* 4850 * Common code for MD __tls_get_addr(). 4851 */ 4852 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4853 static void * 4854 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4855 { 4856 Elf_Addr *newdtv, *dtv; 4857 RtldLockState lockstate; 4858 int to_copy; 4859 4860 dtv = *dtvp; 4861 /* Check dtv generation in case new modules have arrived */ 4862 if (dtv[0] != tls_dtv_generation) { 4863 wlock_acquire(rtld_bind_lock, &lockstate); 4864 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4865 to_copy = dtv[1]; 4866 if (to_copy > tls_max_index) 4867 to_copy = tls_max_index; 4868 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4869 newdtv[0] = tls_dtv_generation; 4870 newdtv[1] = tls_max_index; 4871 free(dtv); 4872 lock_release(rtld_bind_lock, &lockstate); 4873 dtv = *dtvp = newdtv; 4874 } 4875 4876 /* Dynamically allocate module TLS if necessary */ 4877 if (dtv[index + 1] == 0) { 4878 /* Signal safe, wlock will block out signals. */ 4879 wlock_acquire(rtld_bind_lock, &lockstate); 4880 if (!dtv[index + 1]) 4881 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4882 lock_release(rtld_bind_lock, &lockstate); 4883 } 4884 return ((void *)(dtv[index + 1] + offset)); 4885 } 4886 4887 void * 4888 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4889 { 4890 Elf_Addr *dtv; 4891 4892 dtv = *dtvp; 4893 /* Check dtv generation in case new modules have arrived */ 4894 if (__predict_true(dtv[0] == tls_dtv_generation && 4895 dtv[index + 1] != 0)) 4896 return ((void *)(dtv[index + 1] + offset)); 4897 return (tls_get_addr_slow(dtvp, index, offset)); 4898 } 4899 4900 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4901 defined(__powerpc__) || defined(__riscv) 4902 4903 /* 4904 * Return pointer to allocated TLS block 4905 */ 4906 static void * 4907 get_tls_block_ptr(void *tcb, size_t tcbsize) 4908 { 4909 size_t extra_size, post_size, pre_size, tls_block_size; 4910 size_t tls_init_align; 4911 4912 tls_init_align = MAX(obj_main->tlsalign, 1); 4913 4914 /* Compute fragments sizes. */ 4915 extra_size = tcbsize - TLS_TCB_SIZE; 4916 post_size = calculate_tls_post_size(tls_init_align); 4917 tls_block_size = tcbsize + post_size; 4918 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4919 4920 return ((char *)tcb - pre_size - extra_size); 4921 } 4922 4923 /* 4924 * Allocate Static TLS using the Variant I method. 4925 * 4926 * For details on the layout, see lib/libc/gen/tls.c. 4927 * 4928 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4929 * it is based on tls_last_offset, and TLS offsets here are really TCB 4930 * offsets, whereas libc's tls_static_space is just the executable's static 4931 * TLS segment. 4932 */ 4933 void * 4934 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4935 { 4936 Obj_Entry *obj; 4937 char *tls_block; 4938 Elf_Addr *dtv, **tcb; 4939 Elf_Addr addr; 4940 Elf_Addr i; 4941 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4942 size_t tls_init_align, tls_init_offset; 4943 4944 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4945 return (oldtcb); 4946 4947 assert(tcbsize >= TLS_TCB_SIZE); 4948 maxalign = MAX(tcbalign, tls_static_max_align); 4949 tls_init_align = MAX(obj_main->tlsalign, 1); 4950 4951 /* Compute fragmets sizes. */ 4952 extra_size = tcbsize - TLS_TCB_SIZE; 4953 post_size = calculate_tls_post_size(tls_init_align); 4954 tls_block_size = tcbsize + post_size; 4955 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4956 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4957 4958 /* Allocate whole TLS block */ 4959 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4960 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4961 4962 if (oldtcb != NULL) { 4963 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4964 tls_static_space); 4965 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4966 4967 /* Adjust the DTV. */ 4968 dtv = tcb[0]; 4969 for (i = 0; i < dtv[1]; i++) { 4970 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4971 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4972 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4973 } 4974 } 4975 } else { 4976 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4977 tcb[0] = dtv; 4978 dtv[0] = tls_dtv_generation; 4979 dtv[1] = tls_max_index; 4980 4981 for (obj = globallist_curr(objs); obj != NULL; 4982 obj = globallist_next(obj)) { 4983 if (obj->tlsoffset == 0) 4984 continue; 4985 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4986 addr = (Elf_Addr)tcb + obj->tlsoffset; 4987 if (tls_init_offset > 0) 4988 memset((void *)addr, 0, tls_init_offset); 4989 if (obj->tlsinitsize > 0) { 4990 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4991 obj->tlsinitsize); 4992 } 4993 if (obj->tlssize > obj->tlsinitsize) { 4994 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4995 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4996 } 4997 dtv[obj->tlsindex + 1] = addr; 4998 } 4999 } 5000 5001 return (tcb); 5002 } 5003 5004 void 5005 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5006 { 5007 Elf_Addr *dtv; 5008 Elf_Addr tlsstart, tlsend; 5009 size_t post_size; 5010 size_t dtvsize, i, tls_init_align; 5011 5012 assert(tcbsize >= TLS_TCB_SIZE); 5013 tls_init_align = MAX(obj_main->tlsalign, 1); 5014 5015 /* Compute fragments sizes. */ 5016 post_size = calculate_tls_post_size(tls_init_align); 5017 5018 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5019 tlsend = (Elf_Addr)tcb + tls_static_space; 5020 5021 dtv = *(Elf_Addr **)tcb; 5022 dtvsize = dtv[1]; 5023 for (i = 0; i < dtvsize; i++) { 5024 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5025 free((void*)dtv[i+2]); 5026 } 5027 } 5028 free(dtv); 5029 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5030 } 5031 5032 #endif 5033 5034 #if defined(__i386__) || defined(__amd64__) 5035 5036 /* 5037 * Allocate Static TLS using the Variant II method. 5038 */ 5039 void * 5040 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5041 { 5042 Obj_Entry *obj; 5043 size_t size, ralign; 5044 char *tls; 5045 Elf_Addr *dtv, *olddtv; 5046 Elf_Addr segbase, oldsegbase, addr; 5047 size_t i; 5048 5049 ralign = tcbalign; 5050 if (tls_static_max_align > ralign) 5051 ralign = tls_static_max_align; 5052 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5053 5054 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5055 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5056 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5057 5058 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5059 ((Elf_Addr*)segbase)[0] = segbase; 5060 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5061 5062 dtv[0] = tls_dtv_generation; 5063 dtv[1] = tls_max_index; 5064 5065 if (oldtls) { 5066 /* 5067 * Copy the static TLS block over whole. 5068 */ 5069 oldsegbase = (Elf_Addr) oldtls; 5070 memcpy((void *)(segbase - tls_static_space), 5071 (const void *)(oldsegbase - tls_static_space), 5072 tls_static_space); 5073 5074 /* 5075 * If any dynamic TLS blocks have been created tls_get_addr(), 5076 * move them over. 5077 */ 5078 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5079 for (i = 0; i < olddtv[1]; i++) { 5080 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5081 dtv[i+2] = olddtv[i+2]; 5082 olddtv[i+2] = 0; 5083 } 5084 } 5085 5086 /* 5087 * We assume that this block was the one we created with 5088 * allocate_initial_tls(). 5089 */ 5090 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5091 } else { 5092 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5093 if (obj->marker || obj->tlsoffset == 0) 5094 continue; 5095 addr = segbase - obj->tlsoffset; 5096 memset((void*)(addr + obj->tlsinitsize), 5097 0, obj->tlssize - obj->tlsinitsize); 5098 if (obj->tlsinit) { 5099 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5100 obj->static_tls_copied = true; 5101 } 5102 dtv[obj->tlsindex + 1] = addr; 5103 } 5104 } 5105 5106 return (void*) segbase; 5107 } 5108 5109 void 5110 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5111 { 5112 Elf_Addr* dtv; 5113 size_t size, ralign; 5114 int dtvsize, i; 5115 Elf_Addr tlsstart, tlsend; 5116 5117 /* 5118 * Figure out the size of the initial TLS block so that we can 5119 * find stuff which ___tls_get_addr() allocated dynamically. 5120 */ 5121 ralign = tcbalign; 5122 if (tls_static_max_align > ralign) 5123 ralign = tls_static_max_align; 5124 size = roundup(tls_static_space, ralign); 5125 5126 dtv = ((Elf_Addr**)tls)[1]; 5127 dtvsize = dtv[1]; 5128 tlsend = (Elf_Addr) tls; 5129 tlsstart = tlsend - size; 5130 for (i = 0; i < dtvsize; i++) { 5131 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5132 free_aligned((void *)dtv[i + 2]); 5133 } 5134 } 5135 5136 free_aligned((void *)tlsstart); 5137 free((void*) dtv); 5138 } 5139 5140 #endif 5141 5142 /* 5143 * Allocate TLS block for module with given index. 5144 */ 5145 void * 5146 allocate_module_tls(int index) 5147 { 5148 Obj_Entry *obj; 5149 char *p; 5150 5151 TAILQ_FOREACH(obj, &obj_list, next) { 5152 if (obj->marker) 5153 continue; 5154 if (obj->tlsindex == index) 5155 break; 5156 } 5157 if (obj == NULL) { 5158 _rtld_error("Can't find module with TLS index %d", index); 5159 rtld_die(); 5160 } 5161 5162 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5163 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5164 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5165 return (p); 5166 } 5167 5168 bool 5169 allocate_tls_offset(Obj_Entry *obj) 5170 { 5171 size_t off; 5172 5173 if (obj->tls_done) 5174 return true; 5175 5176 if (obj->tlssize == 0) { 5177 obj->tls_done = true; 5178 return true; 5179 } 5180 5181 if (tls_last_offset == 0) 5182 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5183 obj->tlspoffset); 5184 else 5185 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5186 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5187 5188 /* 5189 * If we have already fixed the size of the static TLS block, we 5190 * must stay within that size. When allocating the static TLS, we 5191 * leave a small amount of space spare to be used for dynamically 5192 * loading modules which use static TLS. 5193 */ 5194 if (tls_static_space != 0) { 5195 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5196 return false; 5197 } else if (obj->tlsalign > tls_static_max_align) { 5198 tls_static_max_align = obj->tlsalign; 5199 } 5200 5201 tls_last_offset = obj->tlsoffset = off; 5202 tls_last_size = obj->tlssize; 5203 obj->tls_done = true; 5204 5205 return true; 5206 } 5207 5208 void 5209 free_tls_offset(Obj_Entry *obj) 5210 { 5211 5212 /* 5213 * If we were the last thing to allocate out of the static TLS 5214 * block, we give our space back to the 'allocator'. This is a 5215 * simplistic workaround to allow libGL.so.1 to be loaded and 5216 * unloaded multiple times. 5217 */ 5218 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5219 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5220 tls_last_offset -= obj->tlssize; 5221 tls_last_size = 0; 5222 } 5223 } 5224 5225 void * 5226 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5227 { 5228 void *ret; 5229 RtldLockState lockstate; 5230 5231 wlock_acquire(rtld_bind_lock, &lockstate); 5232 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5233 tcbsize, tcbalign); 5234 lock_release(rtld_bind_lock, &lockstate); 5235 return (ret); 5236 } 5237 5238 void 5239 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5240 { 5241 RtldLockState lockstate; 5242 5243 wlock_acquire(rtld_bind_lock, &lockstate); 5244 free_tls(tcb, tcbsize, tcbalign); 5245 lock_release(rtld_bind_lock, &lockstate); 5246 } 5247 5248 static void 5249 object_add_name(Obj_Entry *obj, const char *name) 5250 { 5251 Name_Entry *entry; 5252 size_t len; 5253 5254 len = strlen(name); 5255 entry = malloc(sizeof(Name_Entry) + len); 5256 5257 if (entry != NULL) { 5258 strcpy(entry->name, name); 5259 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5260 } 5261 } 5262 5263 static int 5264 object_match_name(const Obj_Entry *obj, const char *name) 5265 { 5266 Name_Entry *entry; 5267 5268 STAILQ_FOREACH(entry, &obj->names, link) { 5269 if (strcmp(name, entry->name) == 0) 5270 return (1); 5271 } 5272 return (0); 5273 } 5274 5275 static Obj_Entry * 5276 locate_dependency(const Obj_Entry *obj, const char *name) 5277 { 5278 const Objlist_Entry *entry; 5279 const Needed_Entry *needed; 5280 5281 STAILQ_FOREACH(entry, &list_main, link) { 5282 if (object_match_name(entry->obj, name)) 5283 return entry->obj; 5284 } 5285 5286 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5287 if (strcmp(obj->strtab + needed->name, name) == 0 || 5288 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5289 /* 5290 * If there is DT_NEEDED for the name we are looking for, 5291 * we are all set. Note that object might not be found if 5292 * dependency was not loaded yet, so the function can 5293 * return NULL here. This is expected and handled 5294 * properly by the caller. 5295 */ 5296 return (needed->obj); 5297 } 5298 } 5299 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5300 obj->path, name); 5301 rtld_die(); 5302 } 5303 5304 static int 5305 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5306 const Elf_Vernaux *vna) 5307 { 5308 const Elf_Verdef *vd; 5309 const char *vername; 5310 5311 vername = refobj->strtab + vna->vna_name; 5312 vd = depobj->verdef; 5313 if (vd == NULL) { 5314 _rtld_error("%s: version %s required by %s not defined", 5315 depobj->path, vername, refobj->path); 5316 return (-1); 5317 } 5318 for (;;) { 5319 if (vd->vd_version != VER_DEF_CURRENT) { 5320 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5321 depobj->path, vd->vd_version); 5322 return (-1); 5323 } 5324 if (vna->vna_hash == vd->vd_hash) { 5325 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5326 ((const char *)vd + vd->vd_aux); 5327 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5328 return (0); 5329 } 5330 if (vd->vd_next == 0) 5331 break; 5332 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5333 } 5334 if (vna->vna_flags & VER_FLG_WEAK) 5335 return (0); 5336 _rtld_error("%s: version %s required by %s not found", 5337 depobj->path, vername, refobj->path); 5338 return (-1); 5339 } 5340 5341 static int 5342 rtld_verify_object_versions(Obj_Entry *obj) 5343 { 5344 const Elf_Verneed *vn; 5345 const Elf_Verdef *vd; 5346 const Elf_Verdaux *vda; 5347 const Elf_Vernaux *vna; 5348 const Obj_Entry *depobj; 5349 int maxvernum, vernum; 5350 5351 if (obj->ver_checked) 5352 return (0); 5353 obj->ver_checked = true; 5354 5355 maxvernum = 0; 5356 /* 5357 * Walk over defined and required version records and figure out 5358 * max index used by any of them. Do very basic sanity checking 5359 * while there. 5360 */ 5361 vn = obj->verneed; 5362 while (vn != NULL) { 5363 if (vn->vn_version != VER_NEED_CURRENT) { 5364 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5365 obj->path, vn->vn_version); 5366 return (-1); 5367 } 5368 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5369 for (;;) { 5370 vernum = VER_NEED_IDX(vna->vna_other); 5371 if (vernum > maxvernum) 5372 maxvernum = vernum; 5373 if (vna->vna_next == 0) 5374 break; 5375 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5376 } 5377 if (vn->vn_next == 0) 5378 break; 5379 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5380 } 5381 5382 vd = obj->verdef; 5383 while (vd != NULL) { 5384 if (vd->vd_version != VER_DEF_CURRENT) { 5385 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5386 obj->path, vd->vd_version); 5387 return (-1); 5388 } 5389 vernum = VER_DEF_IDX(vd->vd_ndx); 5390 if (vernum > maxvernum) 5391 maxvernum = vernum; 5392 if (vd->vd_next == 0) 5393 break; 5394 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5395 } 5396 5397 if (maxvernum == 0) 5398 return (0); 5399 5400 /* 5401 * Store version information in array indexable by version index. 5402 * Verify that object version requirements are satisfied along the 5403 * way. 5404 */ 5405 obj->vernum = maxvernum + 1; 5406 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5407 5408 vd = obj->verdef; 5409 while (vd != NULL) { 5410 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5411 vernum = VER_DEF_IDX(vd->vd_ndx); 5412 assert(vernum <= maxvernum); 5413 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5414 obj->vertab[vernum].hash = vd->vd_hash; 5415 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5416 obj->vertab[vernum].file = NULL; 5417 obj->vertab[vernum].flags = 0; 5418 } 5419 if (vd->vd_next == 0) 5420 break; 5421 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5422 } 5423 5424 vn = obj->verneed; 5425 while (vn != NULL) { 5426 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5427 if (depobj == NULL) 5428 return (-1); 5429 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5430 for (;;) { 5431 if (check_object_provided_version(obj, depobj, vna)) 5432 return (-1); 5433 vernum = VER_NEED_IDX(vna->vna_other); 5434 assert(vernum <= maxvernum); 5435 obj->vertab[vernum].hash = vna->vna_hash; 5436 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5437 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5438 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5439 VER_INFO_HIDDEN : 0; 5440 if (vna->vna_next == 0) 5441 break; 5442 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5443 } 5444 if (vn->vn_next == 0) 5445 break; 5446 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5447 } 5448 return 0; 5449 } 5450 5451 static int 5452 rtld_verify_versions(const Objlist *objlist) 5453 { 5454 Objlist_Entry *entry; 5455 int rc; 5456 5457 rc = 0; 5458 STAILQ_FOREACH(entry, objlist, link) { 5459 /* 5460 * Skip dummy objects or objects that have their version requirements 5461 * already checked. 5462 */ 5463 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5464 continue; 5465 if (rtld_verify_object_versions(entry->obj) == -1) { 5466 rc = -1; 5467 if (ld_tracing == NULL) 5468 break; 5469 } 5470 } 5471 if (rc == 0 || ld_tracing != NULL) 5472 rc = rtld_verify_object_versions(&obj_rtld); 5473 return rc; 5474 } 5475 5476 const Ver_Entry * 5477 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5478 { 5479 Elf_Versym vernum; 5480 5481 if (obj->vertab) { 5482 vernum = VER_NDX(obj->versyms[symnum]); 5483 if (vernum >= obj->vernum) { 5484 _rtld_error("%s: symbol %s has wrong verneed value %d", 5485 obj->path, obj->strtab + symnum, vernum); 5486 } else if (obj->vertab[vernum].hash != 0) { 5487 return &obj->vertab[vernum]; 5488 } 5489 } 5490 return NULL; 5491 } 5492 5493 int 5494 _rtld_get_stack_prot(void) 5495 { 5496 5497 return (stack_prot); 5498 } 5499 5500 int 5501 _rtld_is_dlopened(void *arg) 5502 { 5503 Obj_Entry *obj; 5504 RtldLockState lockstate; 5505 int res; 5506 5507 rlock_acquire(rtld_bind_lock, &lockstate); 5508 obj = dlcheck(arg); 5509 if (obj == NULL) 5510 obj = obj_from_addr(arg); 5511 if (obj == NULL) { 5512 _rtld_error("No shared object contains address"); 5513 lock_release(rtld_bind_lock, &lockstate); 5514 return (-1); 5515 } 5516 res = obj->dlopened ? 1 : 0; 5517 lock_release(rtld_bind_lock, &lockstate); 5518 return (res); 5519 } 5520 5521 static int 5522 obj_remap_relro(Obj_Entry *obj, int prot) 5523 { 5524 5525 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5526 prot) == -1) { 5527 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5528 obj->path, prot, rtld_strerror(errno)); 5529 return (-1); 5530 } 5531 return (0); 5532 } 5533 5534 static int 5535 obj_disable_relro(Obj_Entry *obj) 5536 { 5537 5538 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5539 } 5540 5541 static int 5542 obj_enforce_relro(Obj_Entry *obj) 5543 { 5544 5545 return (obj_remap_relro(obj, PROT_READ)); 5546 } 5547 5548 static void 5549 map_stacks_exec(RtldLockState *lockstate) 5550 { 5551 void (*thr_map_stacks_exec)(void); 5552 5553 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5554 return; 5555 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5556 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5557 if (thr_map_stacks_exec != NULL) { 5558 stack_prot |= PROT_EXEC; 5559 thr_map_stacks_exec(); 5560 } 5561 } 5562 5563 static void 5564 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5565 { 5566 Objlist_Entry *elm; 5567 Obj_Entry *obj; 5568 void (*distrib)(size_t, void *, size_t, size_t); 5569 5570 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5571 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5572 if (distrib == NULL) 5573 return; 5574 STAILQ_FOREACH(elm, list, link) { 5575 obj = elm->obj; 5576 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5577 continue; 5578 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5579 obj->tlssize); 5580 obj->static_tls_copied = true; 5581 } 5582 } 5583 5584 void 5585 symlook_init(SymLook *dst, const char *name) 5586 { 5587 5588 bzero(dst, sizeof(*dst)); 5589 dst->name = name; 5590 dst->hash = elf_hash(name); 5591 dst->hash_gnu = gnu_hash(name); 5592 } 5593 5594 static void 5595 symlook_init_from_req(SymLook *dst, const SymLook *src) 5596 { 5597 5598 dst->name = src->name; 5599 dst->hash = src->hash; 5600 dst->hash_gnu = src->hash_gnu; 5601 dst->ventry = src->ventry; 5602 dst->flags = src->flags; 5603 dst->defobj_out = NULL; 5604 dst->sym_out = NULL; 5605 dst->lockstate = src->lockstate; 5606 } 5607 5608 static int 5609 open_binary_fd(const char *argv0, bool search_in_path, 5610 const char **binpath_res) 5611 { 5612 char *binpath, *pathenv, *pe, *res1; 5613 const char *res; 5614 int fd; 5615 5616 binpath = NULL; 5617 res = NULL; 5618 if (search_in_path && strchr(argv0, '/') == NULL) { 5619 binpath = xmalloc(PATH_MAX); 5620 pathenv = getenv("PATH"); 5621 if (pathenv == NULL) { 5622 _rtld_error("-p and no PATH environment variable"); 5623 rtld_die(); 5624 } 5625 pathenv = strdup(pathenv); 5626 if (pathenv == NULL) { 5627 _rtld_error("Cannot allocate memory"); 5628 rtld_die(); 5629 } 5630 fd = -1; 5631 errno = ENOENT; 5632 while ((pe = strsep(&pathenv, ":")) != NULL) { 5633 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5634 continue; 5635 if (binpath[0] != '\0' && 5636 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5637 continue; 5638 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5639 continue; 5640 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5641 if (fd != -1 || errno != ENOENT) { 5642 res = binpath; 5643 break; 5644 } 5645 } 5646 free(pathenv); 5647 } else { 5648 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5649 res = argv0; 5650 } 5651 5652 if (fd == -1) { 5653 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5654 rtld_die(); 5655 } 5656 if (res != NULL && res[0] != '/') { 5657 res1 = xmalloc(PATH_MAX); 5658 if (realpath(res, res1) != NULL) { 5659 if (res != argv0) 5660 free(__DECONST(char *, res)); 5661 res = res1; 5662 } else { 5663 free(res1); 5664 } 5665 } 5666 *binpath_res = res; 5667 return (fd); 5668 } 5669 5670 /* 5671 * Parse a set of command-line arguments. 5672 */ 5673 static int 5674 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5675 const char **argv0) 5676 { 5677 const char *arg; 5678 char machine[64]; 5679 size_t sz; 5680 int arglen, fd, i, j, mib[2]; 5681 char opt; 5682 bool seen_b, seen_f; 5683 5684 dbg("Parsing command-line arguments"); 5685 *use_pathp = false; 5686 *fdp = -1; 5687 seen_b = seen_f = false; 5688 5689 for (i = 1; i < argc; i++ ) { 5690 arg = argv[i]; 5691 dbg("argv[%d]: '%s'", i, arg); 5692 5693 /* 5694 * rtld arguments end with an explicit "--" or with the first 5695 * non-prefixed argument. 5696 */ 5697 if (strcmp(arg, "--") == 0) { 5698 i++; 5699 break; 5700 } 5701 if (arg[0] != '-') 5702 break; 5703 5704 /* 5705 * All other arguments are single-character options that can 5706 * be combined, so we need to search through `arg` for them. 5707 */ 5708 arglen = strlen(arg); 5709 for (j = 1; j < arglen; j++) { 5710 opt = arg[j]; 5711 if (opt == 'h') { 5712 print_usage(argv[0]); 5713 _exit(0); 5714 } else if (opt == 'b') { 5715 if (seen_f) { 5716 _rtld_error("Both -b and -f specified"); 5717 rtld_die(); 5718 } 5719 i++; 5720 *argv0 = argv[i]; 5721 seen_b = true; 5722 break; 5723 } else if (opt == 'f') { 5724 if (seen_b) { 5725 _rtld_error("Both -b and -f specified"); 5726 rtld_die(); 5727 } 5728 5729 /* 5730 * -f XX can be used to specify a 5731 * descriptor for the binary named at 5732 * the command line (i.e., the later 5733 * argument will specify the process 5734 * name but the descriptor is what 5735 * will actually be executed). 5736 * 5737 * -f must be the last option in, e.g., -abcf. 5738 */ 5739 if (j != arglen - 1) { 5740 _rtld_error("Invalid options: %s", arg); 5741 rtld_die(); 5742 } 5743 i++; 5744 fd = parse_integer(argv[i]); 5745 if (fd == -1) { 5746 _rtld_error( 5747 "Invalid file descriptor: '%s'", 5748 argv[i]); 5749 rtld_die(); 5750 } 5751 *fdp = fd; 5752 seen_f = true; 5753 break; 5754 } else if (opt == 'p') { 5755 *use_pathp = true; 5756 } else if (opt == 'v') { 5757 machine[0] = '\0'; 5758 mib[0] = CTL_HW; 5759 mib[1] = HW_MACHINE; 5760 sz = sizeof(machine); 5761 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5762 rtld_printf( 5763 "FreeBSD ld-elf.so.1 %s\n" 5764 "FreeBSD_version %d\n" 5765 "Default lib path %s\n" 5766 "Env prefix %s\n" 5767 "Hint file %s\n" 5768 "libmap file %s\n", 5769 machine, 5770 __FreeBSD_version, ld_standard_library_path, 5771 ld_env_prefix, ld_elf_hints_default, 5772 ld_path_libmap_conf); 5773 _exit(0); 5774 } else { 5775 _rtld_error("Invalid argument: '%s'", arg); 5776 print_usage(argv[0]); 5777 rtld_die(); 5778 } 5779 } 5780 } 5781 5782 if (!seen_b) 5783 *argv0 = argv[i]; 5784 return (i); 5785 } 5786 5787 /* 5788 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5789 */ 5790 static int 5791 parse_integer(const char *str) 5792 { 5793 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5794 const char *orig; 5795 int n; 5796 char c; 5797 5798 orig = str; 5799 n = 0; 5800 for (c = *str; c != '\0'; c = *++str) { 5801 if (c < '0' || c > '9') 5802 return (-1); 5803 5804 n *= RADIX; 5805 n += c - '0'; 5806 } 5807 5808 /* Make sure we actually parsed something. */ 5809 if (str == orig) 5810 return (-1); 5811 return (n); 5812 } 5813 5814 static void 5815 print_usage(const char *argv0) 5816 { 5817 5818 rtld_printf( 5819 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5820 "\n" 5821 "Options:\n" 5822 " -h Display this help message\n" 5823 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5824 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5825 " -p Search in PATH for named binary\n" 5826 " -v Display identification information\n" 5827 " -- End of RTLD options\n" 5828 " <binary> Name of process to execute\n" 5829 " <args> Arguments to the executed process\n", argv0); 5830 } 5831 5832 /* 5833 * Overrides for libc_pic-provided functions. 5834 */ 5835 5836 int 5837 __getosreldate(void) 5838 { 5839 size_t len; 5840 int oid[2]; 5841 int error, osrel; 5842 5843 if (osreldate != 0) 5844 return (osreldate); 5845 5846 oid[0] = CTL_KERN; 5847 oid[1] = KERN_OSRELDATE; 5848 osrel = 0; 5849 len = sizeof(osrel); 5850 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5851 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5852 osreldate = osrel; 5853 return (osreldate); 5854 } 5855 const char * 5856 rtld_strerror(int errnum) 5857 { 5858 5859 if (errnum < 0 || errnum >= sys_nerr) 5860 return ("Unknown error"); 5861 return (sys_errlist[errnum]); 5862 } 5863 5864 /* malloc */ 5865 void * 5866 malloc(size_t nbytes) 5867 { 5868 5869 return (__crt_malloc(nbytes)); 5870 } 5871 5872 void * 5873 calloc(size_t num, size_t size) 5874 { 5875 5876 return (__crt_calloc(num, size)); 5877 } 5878 5879 void 5880 free(void *cp) 5881 { 5882 5883 __crt_free(cp); 5884 } 5885 5886 void * 5887 realloc(void *cp, size_t nbytes) 5888 { 5889 5890 return (__crt_realloc(cp, nbytes)); 5891 } 5892 5893 extern int _rtld_version__FreeBSD_version __exported; 5894 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5895 5896 extern char _rtld_version_laddr_offset __exported; 5897 char _rtld_version_laddr_offset; 5898